Editor

Marcos V. Goycoolea, M.D., M.S., Ph.D. M i n n e s o t a Ear, H e a d & N e c k Clinic

M i n n e a p o l i s , M i n n e s o t a

Co-Editors

Michael M. Paparella, M.D. M i n n e s o t a Ear , Mead & N e c k Cl in ic

M i n n e s o t a

Rick L. Nissen, M.D. M i n n e s o t a Ear , H e a d & N e c k Clinic

M i n n e a p o l i s , M i n n e s o t a

ATLAS OF

Otologic Surgery

1989 W.B. SAUNDERS COMPANY

Harcourt Brace Jovanovirh, Inc . Philadrlphia ' l^ondon / Toronto

Montreal ' Svdnev ' Tokyo

s a u n d e r S c o m p a n y . Brace Jovanovich. Inc.

| u . furt^ Center dependence Square Wesl hiuTdelphia. PA 19106

Library of Congress Cataloging-in-Publication Data

Govcoolea , M a r c o s V .

Alias of o tologic surgery .

Bibliography: p.

I E a r — S u r g e r y — A l i a s e s . I. Paparel la , Michae l M. 11 Nissen , Kick I.. I II . T i t l e . [ D N L M : 1. E a r -s u r g e r y - a l i a ses . W V 1 7 G 7 2 4 a |

RF295.G69 1989 6 I 7 . 8 T O 9

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nor: W, II. Saunders Stall

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^í'iJíiir. Melissa Walter

isfmlim GonnfiiM/or: Waller Verbilski

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l''wr¡ William Cole

a s °< Otologic Surgen' INIOJ (I-72H- -2J37-

1̂9H9 by W. B. Saunders Company. Copyright under the Uniform Copyright Conven Simultan.

'Vrighl No oiisly published in Canada. All rights reserved This hook is protected bv part ol it niay be reproduced, stored in a retrieval system, or transmitted in any

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" d ' K " *» print number: U K 7 li 5 4. .1 2 I

PURO CHILE ES TU CIELO AZULADO PURAS BRISAS TE CRUZAN TAMBIÉN

Y ESE CAMPO DE FLORES BORDADO ES LA COPIA FELIZ DEL EDEN . . .

A TI. DULCE PATRIA

(from the Chilean national anthem)

Contributors

Gwenn Afton, M.S. M e d i c a l I l l u s t r a t o r , M i n n e s o t a E a r , H e a d a n d N e c k C l i n i c a n d B e c k V i s u a l

C o m m u n i c a t i o n s , M i n n e a p o l i s , M i n n e s o t a .

Marcos V. Goycoolea, M.D. , M.S . , Ph.D. M i n n e s o t a E a r , H e a d a n d N e c k C l i n i c . O t o l o g y C o n s u l t a n t , C h i l e a n M i l i t a r y

H o s p i t a l a n d A u d i a C h i l e , S a n t i a g o , C h i l e .

Peter Hilger, M.D. , M.S. A s s i s t a n t P r o f e s s o r , D e p a r t m e n t o f O t o l a r y n g o l o g y , U n i v e r s i t y o f M i n n e s o t a .

S t a f f P h y s i c i a n , S t . P a u l R a m s e y M e d i c a l C e n t e r , S t . P a u l , M i n n e s o t a .

Timothy K. Jung, M.D. , Ph.D. A s s o c i a t e P r o f e s s o r , D i v i s i o n o f O t o l a r y n g o l o g y a n d H e a d a n d N e c k S u r g e r y ,

L o m a L i n d a U n i v e r s i t y , L o m a L i n d a , C a l i f o r n i a .

Sherry Lamey

H e a d t e c h n o l o g i s t , O t o p a t h o l o g y L a b o r a t o r y , D e p a r t m e n t o f O t o l a r y n g o l o g y ,

U n i v e r s i t y o f M i n n e s o t a .

Alan J . Nissen, M.D.

C a l i f o r n i a E a r I n s t i t u t e , P a l o A l t o , C a l i f o r n i a . C l i n i c a l I n s t r u c t o r , S t a n f o r d

U n i v e r s i t y , P a l o A l t o , C a l i f o r n i a .

Rick L. Nissen, M.D. M i n n e s o t a E a r , H e a d a n d N e c k C l i n i c .

Michael M. Paparella, M.D. M i n n e s o t a E a r , H e a d a n d N e c k C l i n i c . C h a i r m a n E m e r i t u s , C l i n i c a l P r o f e s s o r ,

a n d D i r e c t o r o f t h e O t o p a t h o l o g y L a b o r a t o r y , D e p a r t m e n t o f O t o l a r y n g o l o g y ,

U n i v e r s i t y o f M i n n e s o t a .

Donald Robertson, Ph.D. A s s o c i a t e P r o f e s s o r , D e p a r t m e n t o f O t o l a r y n g o l o g y a n d D e p a r t m e n t o f C e l l

B i o l o g y a n d N e u r o a n a t o m y , U n i v e r s i t y o f M i n n e s o t a .

Kurt Schellhas, M.D.

D i r e c t o r o f N e u r o - I m a g i n g , C e n t e r f o r D i a g n o s t i c I m a g i n g , S t . L o u i s P a r k ,

M i n n e s o t a .

V

vi C o n t r i b u t o r s

R o b e r t S m i t h , M . D .

C h i e f R e s i d e n t , D e p a r t m e n t o f O t o l a r y n g o l o g y , U n i v e r s i t y o f M i n n e s o t a .

E d w a r d W . S z a c h o w i c z , M . D . , P h . D .

A s s i s t a n t P r o f e s s o r , D e p a r t m e n t o f O t o l a r y n g o l o g y , U n i v e r s i t y o f M i n n e s o t a .

S t a f f P h y s i c i a n , S t . P a u l R a m s e y M e d i c a l C e n t e r , S t . P a u l , M i n n e s o t a .

Motto

Learn to learn from everything you do and everybody around you.

•

Key Words

A n a t o m y

F u n c t i o n

P a t h o g e n e s i s

R e s e a r c h

O p e n m i n d

C o m m o n s e n s e

D e d i c a t i o n

Preface This book is written primarily for physicians in training (residents). It is

my aim to make it a dialogue with you, the residents, beginning with the preface itself. The origin of this book goes back to my first year of residency in Otolaryngology. Although many good texts were available, 1 felt that I needed a book that went back to basics in clear and understandable language, and that would provide me with the essential concepts from which to start. It seemed to me that a complicated organ such as the ear could be made, at least at that stage, a little simpler (not simple). Over time 1 have been thinking of different aspects that 1 felt to be important and useful for this purpose, and 1 asked the different contributors to do the s a l * . Accordingly, we have tried to create a book that emphasizes the basics, rather than one that shows our methods.

In the same context, this atlas is only intended to complement other texts on the subject. Because this is primarily a conceptual atlas, we have made no attempt to provide detailed discussions of evaluations and indications; such discussions are provided by the works cited in the list of selected references. This list also includes publications that describe essential concepts of anatomy and function. Because of the extent of these subjects, the works available number in the thousands; we apologize to, those authors whose important publications are not cited owing to lack of space and request their understand­ing. We are aware that this first edition will need improvements. It is our hope that these will come from your criticisms and suggestions.

There are a number of thoughts and general philosophies that 1 believe are useful. 1 do not expect you to agree with them but to be exposed to them and think. Some of them will make sense, some will not. 1 hope that some of the latter will make sense to you in, time.

The techniques described in "this book are intended to show different approaches based on the knowledge of anatomy, function, and pathology. They are oriented more toward a way of thinking than toward a dogma of doing, in the expectation that the surgeon will think of each surgical procedure as a distinct and different act. It is my hope that this will allow the surgeon to vary an approach according to need> habit, or ability at a specific time. 1 believe that there is no single best technique for otologic surgery; in order to achieve a safe and efficient result, different surgeons might select different but equally valid approaches. It is easy to be rigid; it is even successful, on the whole. It is harder to tailor your approach case by case since this requires an overall concept. In the long run, however, it is much more rewarding. Research and knowledge of anatomy and pathogenesis permit proper changes and improve­ments. Ear surgery can be what you want it to be. If it is to be developed into an art, knowledge, creativity, dynamism, and an open mind, together with common sense, are essential. As in any discipline, there are basic principles; however, they should be regarded not as rigid rules but rather as underlying philosophies. An essential point to be remembered is that the aim of surgery is to solve problems. Patients come to you for you to solve their problem, not for the surgery itself. In the same context, solving a problem does not mean applying formulas or fitting patients into treatment classifications. Classifica-

xi

XU Preface

tions and formulas are nothing more than common sense put on paper—use them as a tool, do not be "ruled by them." This may seem like a subtle concept but it makes all the difference in the world. The difference between operating and solving a problem is like the difference between passing a cloth over a table and cleaning the table.

Another important concept implied here is what I call the concept of "intent." For all actions that are to be translated into an efficient result, there must be the intention of obtaining such a result. This involves the rational use of your senses. When you look through the operating microscope you must s e e , observe, analyze, and use the information obtained. This is quite different from "glancing." You must know what you are looking at (based on anatomy) and the most likely possibilities and alternatives that can be found (based on pathogenesis).

It is also essential to understand that surgery is in the mind and the heart and not primarily in the hand. Good hands are important, but they are not enough. A mechanical task can be performed brilliantly by a moron if it is done over and over again in the same fashion. The art of surgery lies as much in the choices as in the act itself, and also in the postoperative care. The medical act begins with the first clinical visit and ends when the problem is solved.

It is always tempting to simplify our lives with what is "usual" and "customary." If you are in pursuit of excellence, avoid this temptation. A common attitude of residents (we have all been residents and I have not forgotten the experience) is to proceed as the "books say" or the "journal says." Books and journals (including this one) do not say anything; they present what different authors believe. Although important and valuable, this information should be treated as a reference, not as dogma.

On patient evaluation: Despite the fact that the amount of information available and the precision of laboratory studies have had a great impact on today's medicine, the essential process of evaluation remains unchanged. Regardless of the facilities available, the patient's history and examination are as critical as ever. Provided that they are done properly, a diagnosis is reached most of the time based on history and examination alone. For children, the parents (usually the mother) are crucial in providing information. Regardless of a mother's background, she is the one who spent the night with the sick child and provided food, clothing, cleansing, and so on. The mother will not tell you what to diagnose and do, but she will provide important clues for the diagnosis, and at times for treatment. Again, our role is to listen respectfully and learn; then, using our knowledge, diagnose and if possible tench. Labora­tory studies confirm impressions, provide documented objective evidence, and rule out or detect problems or lesions not detectable otherwise. Much can be said about this; suffice it to mention that laboratory studies are ordered with specific questions in mind, and should not be ordered if the results are not oriented toward an action to be taken.

On the procedure of choice: Apart from strict physiopathology, there are other factors to consider in deciding what benefits an individual most. What is good for some may not be good for others. A procedure that requires frequent checkups might not benefit somebody who cannot be checked periodically. People and circumstances vary and so should your solutions. Although it is our duty to change attitudes for the better, it is common sense to accept that some things cannot be changed.

On the risks of surgery: it is important to reiterate that it is the patient who takes the risk, not the surgeon. How warranted a specific risk is will depend on the patient's situation and needs, and calls for common sense on the part of the surgeon. A surgeon should be conservative. Although "every­body has something that can be operated upon," the surgeon's role is to assess

1

Preface X I I I

if the operation is indicated and really helpful. Conservatism should be a product both of knowledge and of profound respect for an individual who has trusted you; it should not come from ignorance or inability to perform what is needed. As for doing what other surgeons do successfully, again, their experience should be seen as background and reference and not as dogma. It is fine to imitate others and this should be done by all means, provided that what is imitated is understood, agreed upon, and applicable to your patients. It is important to evaluate and rationalize what the leading surgeons do; behind each of the true leading surgeons are many hours of study and hard work. Question positively their methods and rationale. Ask yourself what is intended by a specific method and why. Is it reasonable? Is it the best way? "Trendy" procedures and "state of the art" instruments also require thorough knowledge and understanding. They usually have good reasons behind them; you must understand and agree with those reasons. If all you need to do is kill a fly, use a 50-cent fly swatter; do not buy a $50,000 electronic fly killer because it is "state of the art ." Trends come and trends go. Use common sense when investing.

Otologic surgery, like medicine itself, is a never-ending learning process. You are never too good to learn from everybody else. Seeking advice is a sign not of weakness but of maturity. Learn to use your senses; observe and listen to other surgeons and specialists, the operating team, your patients, and others. Learn positively from those who want to help you and from those who want to harm or use you. Learn to'Jearn from everything you do and everybody around you. Each surgical cas< is different. When placing pressure-equalizing tubes, study the ear canals and their contents, the tympanic membrane, the middle ear mucosa, characteristics of the effusion, and so on. Relate them to one another, to the laboratory studies, and to the clinical history. This simple process will enrich you and you will learn what you never thought you would. A difficult task is to learn how to accept reality and our lack of true knowledge. As hard as it is to deal with success, it is harder and demands more stamina to deal with failure. Complications and unwanted results do happen, even if you seemingly have done your job properly. Objective self-assessment and complete revision of the subject should follow every failure, even .if it "was bound to happen." You may easily forget 200 successful stapedectomies and never forget one case of hearing loss due to a reparative granuloma. You must also learn to accept that in many cases in otology, surgery does not turn back the disease process, and that different individuals have different responses to similar surgical procedures and different healing capabilities. From this stand­point alone, the results of tympanoplasty may vary from 60% to 100%. A 60% success in a population with .poor nutritional background can be better than 90% in one with optimal nutrition. Percentages are relative; your own and those of others should be analyzed in their full context. There are many other points and ideas that 1 would, have liked to discuss here. Some of them are discussed in the text. U

A few words on the contributors to this atlas: Gwenn Afton, the illustrator, has an MS in Medical Illustration from the

Medical College of Georgia. I had the privilege of writing the temporal bone dissection manual that she illustrated as her master's thesis. At the time she not only performed such dissections herself but requested direct supervision and explanations. In spite of her being by far the youngest member of this team, her professionalism, dedication, interest, and talents are what 1 would have expected from an experienced and famed medical illustrator. I worked directly with her on each and every drawing (in all chapters) in this atlas. However, it must be mentioned that the designs for Chapter 1 (Pertinent Anatomy) were selected by Donald Robertson; for the discussions of neuro-

xiv Preface 4 Preface XV

Donald Robertson has headed the anatomy course for medical and

graduate students in the Department of Cell Biology and Neuroanatomy

(formerly Department of Anatomy), and the yearly course in Head and Neck

Anatomy for otolaryngology residents for 17 years at the University of Minne­

sota. Having been his student both as a resident and as a graduate in anatomy,

1 have appreciated the value of his experience and his teaching. It has been a

privilege for me to have him contribute Chapter 1 (Pertinent Anatomy).

Kurt Schellhas has contributed Chapter 3 (Pertinent Concepts in High

Resolution Temporal Bone Imaging). Kurt went to medical school, did his

residency, and took his neuroradiology fellowship at the University of Minne­

sota. His experience with and clarification of concepts in diagnostic imaging in

otology have been instrumental in this short but conceptual chapter.

Chapter 20 (Plastic Surgery of the Pinna) was written by Ed Szachowicz,

Peter Hilger, and Robert Smith. Ed and Peter trained in Otolaryngology under

Michael Paparella. Ed had postdoctoral training in Plastic Surgery with Drs.

William Wright and Russell Kridel in Houston and Dr. Clyde Litton in

Washington, DC. Peter had his postdoctoral training in Plastic Surgery at

Harvard Medical School and Massachusetts Eye and Ear Infirmary under Dr.

Richard Webster. Robert is currently a Chief Resident at the Department of

Otolaryngology at the University of Minnesota.

Other contributors to this atlas are Dr. Hammed Sajjadi, formerly a Fellow

in our clinic (1986-1987) , who assisted with Chapter 6 (Operating Room

Principles and General Concepts) , and Drs. Michael Morris and Richard Fox,

currently otology Fellows, w h o served as reviewers and critics. Professor A.

Rosales from Santa Cruz, Bolivia, provided me with the diagrams and design

of his consistently successful piston wire prosthesis. David Muchow took the

scanning electron micrograph of the stapes used on the cover, and Jodi Nielsen,

the radiology and vestibular technologist and medical photographer at the

Minnesota Ear, Head and Neck C.inic, took the photographs in Chapter 6. The

"patients" in this chapter are my children Marcos and Hortensia, and the nurse

is Joanne Eplev, RN, head nurse at our institution. Kay Emery typed and

edited the manuscript and Joyce Hansen assisted in typing. Gail E. Mowen

assisted Alan Nissen with his chapter.

The contributions of grants N«. 5P-50-NS-14538 from the National Institute

of Neurological and Communica'ive Disorders and No. NS-19433-04 from the

Deafness Research Foundation, as well as a grant from the 3M Company of

Minnesota, arc acknowledged.

A final note: The opinions in this preface, as well as the selection of the

dedication, key words, and motto, are my own and do not necessarily represent

the opinions and choices of the contributors to this atlas.

M a r c o s V . G o y c o o l e a , M . D .

otology (in Chapters 5, 17, 18, and 19) by Rick Nissen; and for Chapter 14

(Lasers in Otologic Surgery) by Alan Nissen. We have been asked to lend many

of the illustrations (only those designed by Gwenn and me) to Michael Paparella

for the otology volume of his forthcoming text. 1 have no doubt that with the

appearance of this atlas we are also witnessing the emergence of an artist who

will be a significant contributor to medical illustration in the coming years.

Timothy Jung is my former fellow resident at Minnesota. Tim oriented

his research toward biochemistry of the ear and has remained working in this

area while practicing primarily clinical otolaryngology. He has contributed

directly to the discussions of the Thiersch graft (in Chapter 7) and mastoid

obliteration and surgery for complications of suppurative otitis media (in

Chapter 10), and is wholly responsible for Chapter 8 (External Ear Canal

Procedures). His clinical and surgical experience, coupled with his approach

toward ear disease based on anatomy and pathogenesis, made him a natural

contributor to this book.

Sherry Lamey has headed the Otopathology Laboratory at the University

of Minnesota for 20 years. She is, in my opinion, directly responsible for

transforming this laboratory into one of the best, if not the best, of its kind in

the world. Many generations of residents (including mine) and research fellows

have benefited from her knowledge and expertise. The histology and histopa-

thology slides in this atlas, as well as Chapter 4 (Temporal Bone Removal), are

all products of her work.

In order to include a solid discussion of the use of lasers in otologic

surgery (Chapter 14), we asked Alan Nissen to be a contributor. Alan trained

at the University of Nebraska and took a postdoctoral fellowship with Dr.

Michael Glasscock in Tennessee. He is currently a member of the California

Ear Institute in Palo Alto, where he has developed expertise in the use of

lasers.

Rick Nissen is a member of our team at the Minnesota Ear Head and

Neck Clinic, where he directs the Neuro-otology division. Rick did his residency

•it the University of Nebraska and hail his postdoctoral training in Neuro-

otology at the House Ear Institute in Los Angeles, lie started as a contributor

tn this atlas, but his interest, efficiencv, and understanding of the spirit of the

h o o k were such that he also became a co-editor of the chapters dealing wholly

or in part with ncuro-otologv (Chapters 5, 17, IK. and 19). This section is the

product of his work.

Michael PaparWI.i was Professor and Chairman of flu' Department ol

Olobryngologv at the L'nivcrsitv ot Minnesota for 17 ve.IRS. Under h i s leader­

ship, the department became one ol the primarv otologv centers in the world,

both clinically and in research. H i s contributions to our specialty in the last

two decades have been among the most significant by any single individual,

a n d his name has a well-deserved place of honor in the historv of otology. In

addition, he had the vision and openness to train specialists from all over the

world. The results of his teachings and philosophies are becoming more evident

every year as his former students gradually reach the highest academic positions

both in the United States and abroad. After his retirement as active chairman,

he developed the Minnesota Ear, Head and Neck Clinic. Clinically more active

'han ever, he has continued doing research as Clinical Professor and Director

of t h e Otopathology Laboratory at the University of Minnesota. 1 originally

trained with him in Minnesota and have rejoined him at the Minnesota Ear,

H e a d and Neck Clinic. When 1 came from Chile to train with him, he opened

' h e doors of the department and of his friendship to me. He has undoubtedly

had a direct influence on my training; at the same time, he has trained many

°f the contributors to this work. It was a privilege for me to have Michael as a c » editor of this atlas.

? Contents i

SECTION I Basic Anatomic Concepts 1

CHAPTER 1 Pertinent Anatomy '. 3

Donald Robertson, Ph.D.

CHAPTER 2 Pertinent Histology 23

Marcos V. Goycoohar M.D., M . S . , Ph.D.

CHAPTER 3 Pertinent Concepts in High Resolution Temporal

Bone Imaging 28

Kurt Sdwtlhas, M.D.

SECTION II Temporal Bone Dissection 37

CHAPTER 4 Temporal Bone Removal 39

Marcos V. Goycooiea, M.D., M.S., Ph.D. Sherry Lamcy

CHAPTER 5 Surgical Procedures 44 Marcos V. Goycoolea, M.D., MS.^Ph.D. Kick L. Nisscrt, M.D.

SECTION III General Principle<vand Approaches 99

CHAPTER 6 Operating Room Principles and General Concepts 101

Marcoa V. Goycootca, M.D.. M.S.? Ph.D

CHAPTER 7 Surgical Approaches to the External Ear Canal and Middle Ear j 121

Marcos V. Goycaalea, M.D., M.S., Ph.D. Timothy K. Jung, M.D., Ph.D.

SECTION IV Specific Surgical Approaches 147

CHAPTER 8 External Ear Canal Procedures 149

Timothy K. Jung, M.D., Ph.D.

CHAPTER 9 Congenital Atresia 159

Marcos V. Goycookar M.D., M . S . , Ph.D.

CHAPTER 10 Surgical Procedures in Different Forms of Otitis Media . . . 164

Marcos V. Goycoolea, M.D., M.'g., Ph.D. Timothy K. Jung, M.D., Ph.D.

x v i i

XVlii Contents

K U > 363

SECTION I

Basic Anatomic Concepts

CHAPTER 11 Exploratory Tympanotomy 210 Marcos V. Guycoofoi, M.D., M . S . , Ph.D.

CHAPTER 12 Tympanoplasty 218

Marcos V. Coycoolea, M.D., M.S., Ph.D.

CHAPTER 13 Surgery for Stapes Fixation 247 Marcos V. Coycoolea, M.D., M.S., Ph.D.

CHAPTER 14 Lasers in Otologic Surgery 272 Alan }. Nissen, M.D.

CHAPTER 15 Surgical Approach for Bone Conduction

Hearing Devices ... 281 Marcos V. Coycoolea, M.D., M.S., Ph.D.

CHAPTER 16 Surgical Approaches for Cochlear Implants 286 Marcos V. Cm/coolea, M.D., M.S., Ph.D.

CHAPTER 17 Surgery for Incapacitating Peripheral Vertigo 297 Marcus V. Coycoolea, M.D.. M.S., Ph.D. Rick l. Nisse«, M.D.

CHAPTER 18 Infratemporal Facial Nerve Surgery 315

Marius V. Govorita. M.D., M.S., Ph.D. Rnk L. Nissen, M.D.

CHAPTER 19 Tumors of the Middle and Inner Ear 325 Marius V. Coycoolea, M.D.. M.S., Ph.D. Rick L. Nissen. M.D.

CHAPTER 20 Plastic Surgery of the Pinna 3 3 9 Peter Hilter, M.D., M.S. M v r f Smith, M . D . l.tlward W. Szachowicz. M.D.. Ph.D.

SECTION V Selected References 3 5 9

CHAPTER 1

Pertinent Anatomy

F o r d e s c r i p t i v e p u r p o s e s t h e e a r i s d i v i d e d i n t o

t h r e e p a r t s : (1) t h e e x t e r n a l e a r , c o n s i s t i n g o f t h e

a u r i c l e , t h e e x t e r n a l a c o u s t i c m e a t u s , a n d t h e t y m ­

p a n i c m e m b r a n e ; ( 2 ) t h e m i d d l e e a r ( t y m p a n i c c a v i t y )

a n d t h e a s s o c i a t e d o s s i c l e s a n d m u s c l e s ; a n d ( 3 ) t h e

i n n e r e a r , c o n t a i n i n g t h e o r g a n s o f e q u i l i b r a t i o n a n d

h e a r i n g .

The External Ear

Bony Features and Relationships

T h e b o n y c o m p o n e n t s o f t h e e x t e r n a l e a r ( F i g . 1 ¬

1 ) a r e all p a r t o f t h e t e m p o r a l b o n e . T h e y i n c l u d e t h e

f o l l o w i n g :

1. T h e squamous portion, f o r m i n g a s m a l l , s u p e r i ­

o r l y l o c a t e d p a r t o f t h e b o n y e x t e r n a l a u d i t o r y m e a t u s

a n d t h e a n t e r o l a t e r a l p o r t i o n o f t h e m a s t o i d p r o c e s s .

E x t e n d i n g l a t e r a l l y a n d a n t e r i o r l y f r o m t h e i n f e r i o r

p a r t o f t h e s q u a m o u s p o r t i o n o f t h e t e m p o r a l b o n e

i s t h e zygomatic process, w h i c h h a s t h r e e r o o t s . T h e

anterior root e x t e n d s m e d i a l l y lo b e c o m e c o n f l u e n t

w i t h t h e a r t i c u l a r t u b e r c l e ; t h e medial root f o r m s t h e

p o s t e r i o r wa l l o f t h e m a n d i b u l a r fo s sa ; a n d t h e pos­

terior root c u r v e s s l i g h t l y d o w n w a r d o n t o t h e m a s t o i d

p r o c e s s . T h i s r o o t b e a r s t h e s m a l l suprameatal spine

( o f H e n l e ) o n i ts d o r s a l e x t r e m i t y . H e n c e , t h e u p p e r

p o r t i o n o f t h e e x t e r n a l a c o u s t i c m e a t u s i s l o c a t e d

b e t w e e n t h e m i d d l e a n d p o s t e r i o r r o o t s . T h e c r e s t o f

t h e p o s t e r i o r r o o t a n d t h e p o s t c r o s u p e r i o r p o r t i o n o f

t h e b o n y m e a t u s a r e j o i n e d b y a n i m a g i n a r y l ine t o

f o r m t h e suprameatal triangle, m a r k i n g t h e s i t e o f

a c c e s s t o t h e a n t r u m o f t h e m i d d l e e a r .

2 . T h e tympanic portion, f o r m i n g m o s t o f t h e b o n y

m e a t u s . T h e g r e a t e s t p a r t o f th i s c o m p o n e n t d e v e l o p s

a f t e r b i r t h , a n d t h e a l t e r a t i o n i n f o r m a s i t d e v e l o p s

b r i n g s a b o u t a shif t i n t h e d e p t h o f ( h e e x t e r n a l

m e a t u s a s wel l a s i n t h e o r i e n t a t i o n o f t h e t y m p a n i c

m e m b r a n e . In t h e n e w b o r n i t i s a s l i gh t b o n e r ing

t h a t i s i m p e r f e c t s u p e r i o r l y . W i t h s u b s e q u e n t

g r o w t h , s m a l l p r o j e c t i o n s o f b o n e a r i s i n g f r o m its

a n t e r i o r a n d p o s t e r i o r c r u r a e x t e n d i n t o t h e l u m e n

o f t h e r i n g , e v e n t u a l l y f u s i n g t o d i v i d e t h e a n n u l u s

i n t o t h e s u p e r i o r l y l o c a t e d a c o u s t i c m e a t u s p r o p e r

a n d a s m a l l , i n t e r i o r l y s i t u a t e d a p e r t u r e . A l t h o u g h

t h e l a t t e r u s u a l l y c l o s e s w i t h c o n t i n u e d d e v e l o p m e n t ,

i t m a y o n o c c a s i o n p e r s i s t t o f o r m w h a t i s d e s i g n a t e d

t h e foramen o f Huschke. T h e s u p e r i o r l y l o c a t e d d i s c o n ­

t i n u i t y i n t h e t y m p a n i c r i n g p e r s i s t s i n t o a d u l t life a s

t h e tympanic notch ( o f R i v i n u s ) .

P o s t e r i o r l y t h e t y m p a n i c r i n g f o r m s , i n c o n j u n c ­

t i o n w i t h b o t h t h e s q u a m o u s a n d p e t r o u s p o r t i o n s

o f t h e m a s t o i d p r o c e s s , t h e tympanomastoid a n d petro­

tympanic s u t u r e s ( f r e q u e n t l y d e s i g n a t e d c o l l e c t i v e l y

t h e t y m p a n o m a s t o i d s u t u r e ) . A n t e r i o r l y t h e r i n g p a r ­

t i c i p a t e s i n t h e f o r m a t i o n o f t h e squamotympanic a n d

petrotympanic s u t u r e s . I t i s in t h e l a t t e r s u t u r e t h a t

t h e f o r a m e n t r a n s m i t t i n g t h e c h o r d a t y m p a n i n e r v e

( t h e i t e r c h o r d a e a n t e r i u s ) i s f o u n d . I t s h o u l d b e

a p p r e c i a t e d t h a t t h e t y m p a n i c r i n g , w i t h i ts g r o w t h ,

f o r m s a p o r t i o n o f t h e p o s t e r i o r wa l l o f t h e m a n d i b ­

u l a r f o s s a .

3 . T h e petrous portion, f o r m i n g t h e t i p a n d p o s t e ­

r i o r p o r t i o n o f t h e m a s t o i d p r o c e s s .

The Auricle

T h e a u r i c u l a r c o m p o n e n t o f t h e e x t e r n a l e a r c o n ­

s i s t s o f a s i n g l e c a r t i l a g i n o u s p l a t e w i t h its c o v e r i n g

s k i n . T h i s c a r t i l a g e f r a m e w o r k i s r e s p o n s i b l e for t h e

s h a p e o f t h e a u r i c l e , a n d d e t e r m i n e s all o f t h e v a r i o u s

4 Pertinent Anatomy

FIGURE 1-1. Bum l ' o m p n n c n N i>l tin- cvlt-rn.il r.ir

Prominences and depressions seen on the ear, with

he exception of the lobule.

In addition to the features that are superficially

hscemible, the cartilage plate contains other features

hat become evident upon removal of overlying skin,

"riese include the following (Fig. 1-2/1):

1- The spine of the helix, projecting anteriorly from n e helix, near the c m s .

2 The tail of the helix (cauda helix), the terminal

W i o n of the helix, located at the posteroinferior n a r g i n of the auricle.

3 The isthmus, the point of continuity between 1 e auricular and meatal cartilages, located imme-l a'ely posterior to the entrance of the external mea-Js.

I t I

+. The lermmai incisure, between the isthmus and

the tragal lamina of the auricular cartilage. Its inferior

extremity is the opening of the external meatus.

Superiorly it is marked by the anterior incisure.

The auricle is attached to the side of the head by

the following features:

1. Its continuity with the cartilaginous portion of the

external acoustic meatus.

2. The skin covering the ear and continuing onto the

skull. The skin of the auricle is tightly bound to

the perichondrium of the lateral aspect of the ear

but is somewhat freer on the medial surface. There

is very little fat in the subcutaneous tissue of the

ear. Except in the tragal and antitragal regions,

the hair of the auricle is rudimentary. Sebaceous

Pertinent Anatomy

F 1 C U R E 1-2 .

A, Major relationships of the auricular cartilage.

External acoustic meatus.

Mastoid air cells

B

£ Pertinent Anatomy

g l a n d s are present on both surfaces and are par­t i cu la r ly numerous in the concha and triangular

fossa .

3 Three extrinsic ligaments. These include: A. The anterior ligament, extending from the zyg­

oma to the helix and the tragus. ¡ 3 . The superior ligament, extending from the su­

perior margin of the bony meatus to the spine of the helix.

C. The posterior ligament, extending from the mas­toid process to the concha of the auricle,

i. Muscles, consisting of the following: A An extrinsic group, formed of three small mus­

c le s (anterior, superior, and posterior) belong­ing to the facial group of muscles and supplied by the facial nerve.

B. An intrinsic group of six small muscles, which are extremely variable in their development and have no functional significance in humans.

The External Acoustic Meatus

or fissures of Santorini), which assist in imparting a limited mobility to the auricle.

The major relationships of the meatus are the following (Fig. 1-2B):

1. Anteriorly and laterally, the parotid gland. The more medial and anterior relationships include the mandibular fossa and the condyle of the mandible.

2. Inferiorly, the parotid gland.

3. Superiorly and medially, the epitympanic re­cess of the middle ear.

4. Posteriorly, the mastoid air cells.

The skin lining the external meatus is continuous with that of the auricle, and also forms the external layer of the tympanic membrane. It varies consider­ably in thickness, being much heavier in the cartilag­inous portion of the meatus where there is a popu­lation of large sebaceous glands and numerous fine hairs. The skin of the bony meatus, which is much thinner, is firmly bound to the periosteum of the underlying bone and contains a rather sparse popu­lation of glands and hair cells, located predominately on the superoposterior wall.

The external acoustic meatus is a bony-cartilagi-ous c ana l extending from the concha of the auricle 5 the tympanic membrane. In its adult configuration

d e s c r i b e s a slight S-shape, with the lateral cartilag-lous portion somewhat concave anteriorly and in-TOirly and the medial bony portion slightly concave o s t e r i o r l y and superiorly. Owing to the obliquity of le tympanic membrane, the posterosuperior wall of le m e a t u s is slightly shorter than the anteroinferior •all (approximately 25 mm and 31 mm, respectively), l ightly more than half of the external meatus is ntirely bony (medially), with the anterior wall, floor, nd lower posterior wall formed by the tympanic ortion of the temporal bone. Its roof and the upper art of t he posterior wall are formed by the squamous ortion.

The cartilaginous (lateral) portion of the external ea tus forms a trough-shaped structure that is open iper ior ly and posteriorly. This canal is completed

' he latter quadrants by the squamous portion of e temporal bone. In addition to being slightly >™ed, it is somewhat broader in its lateral aspect " e r e it makes up approximately two thirds of the rcumference of the meatus. Medially it makes up " g h l y one third of the meatal wall. At its lateral •tremity the cartilage of the meatus is continuous ' " i that of the auricle through the isthmus; medi-y. it articulates with the bony portion of the mea-5 T h e anterior wall is characterized by the presence

h v " fissures (incisures of the cartilaginous meatus

The Tympanic Membrane

The tympanic membrane (Fig. 1-3/1) is a thin, elliptically shaped membrane situated between the medial end of the external meatus and the middle ear cavity. Its vertical axis measures approximately 9 to 10 mm; its horizontal axis measures approximately 8 to 9 mm. In its final adult position the tympanic membrane slopes medially from superior to inferior and from posterior to anterior, so that its external (meatal) surface faces somewhat inferiorly and an-terolaterally. In the newborn the membrane is situ­ated much more horizontally, but gradually shifts to the adult position with development of the tympanic portion of the temporal bone.

The major features of the tympanic membrane, as viewed from the lateral aspect, include the following:

1. The umlw, which is the center of the slight lateral concavity. It marks the point of attachment of the tip of the manubrium of the malleus.

2. The malleal stria, extending superiorly and slightly anteriorly from the umbo. It is formed by the manubrium of the malleus. The stria and a perpen­dicular line extending through the umbo divide the membrane into quadrants (anterosuperior, anteroin­ferior, posterosuperior, and posteroinferior).

3. The mallear prominence, marking the attachment of the lateral process of the malleus to the membrane. Extending from the prominence in anteroinferior and

Pertinent Anatomy 7

M a l l e a r p r o m i n e n c e

Umbo A n t . m a l l e a r t o l d

Para flaccida

P o s t , m a l l e a r told

F I G U R E 1 - 3 .

A, Tympanic membrane. B, Vascular supply of the tympanic membrane.

posteroinferior directions are, respectively, the ante­rior and posterior mallear folds.

4. The purs fensa, that portion of the membrane lying below the mallear prominence and the mallear folds and making up the greatest part of the mem­brane.

5. The purs flaccida, that portion of the membrane lying above the mallear prominence and the mallear folds. It is named for its characteristic laxity.

Structurally, the membrane consists of three layers

approximately 0.1 mm thick (combined). These in­

clude: »,

1. An outer cutaneous layer of thin skin, which is continuous with the skin of the external meatus.

2. A middle layer of connective tissue consisting of

the following:

A. The radiate fibrous layer, made up of fibers radiating peripherally from the umbo and ma­nubrium of the malleus.

B. The circular fibrous layer, made up of concen-

g Pertinent Anatomy

Vascular Supply of the

External Ear

T h e arteries of the external ear originate from severa l sources. The auricle has an abundant blood supply, which is derived primarily from the posterior

auricular branch of the external carotid artery and the auricular rami arising from the superficial temporal artery. These are shared by the meatus, which also rece ives the deep auricular branch of the maxillary artery. Thi s artery passes through the parotid gland to enter ei ther the cartilaginous or bony part of the meatus.

T h e tympanic membrane is supplied on both its lateral and medial surfaces. Laterally, the deep auric­ular artery forms a small peripheral vascular ring from which small branches radiate onto the mem­brane . Superiorly, a large vessel, the external descend­ing artery, arises from the vascular ring to descend to the region of the umbo, with a course more or less parallel to the manubrium (Fig. 1-3B). Internally, a second peripheral vascular ring is formed primarily by the stylomastoid branch of the posterior auricular artery and t h e anterior tympanic branch of the maxillary artery. The largest of the vessels arising from this inner vascular ring is the internal descending artery, which descends on the inner surface of the membrane in a course parallel to that of its external counterpart.

T h e venous channels draining the structures of Ihe external ear roughly correspond to the arteries of supply. Those draining the auricle and the external meatus are the anterior auricular tributaries of the superficial temporal veins and the auricular tributaries o f the posterior auricular vein. Drainage of the tym-P a r " c membrane is both external (via vessels com-m"nicating with veins of the external meatus) and "iternal (via branches paralleling the arteries).

innervation of the External Ear

The external ear is a region of transition between l n originally overlying the branchial area and the

postbranchial region. For this reason, both the cranial; nerves supplying the branchial arches (V, VII, IX, I and X) and the cervical nerves may be represented; by sensory components. Although there is consid ! erable variation, the approximate sensory D I S T R I B U T ;

Hon is as follows (Fig. 1-4): . ̂

1. The cervical plexus of nerves ( C 2 - 3 ) , via the' great auricular nerve, supplies most of the lateral' surface of the auricle (except for the upper anterior '. portion). The lesser occipital nerve from the plexus supplies much of the medial surface of the auricle.

2. The mandibular division of the trigeminal nerve, via its auriculotemporal branch, supplies the upper anterior portion of the auricle, the upper and ' anterior walls of the external meatus, and the upper L anterior part of the lateral surface of the tympanic membrane. '

3. The auricular branch of the vagus supplies ap¬ proximately half of the external meatus and lateral 1

surface of the tympanic membrane. Although this nerve is typically described as being of vagal origin, t

it should be appreciated that branches of VII and IX.! may join it and contribute to the sensory innervation , of the external ear. It is impossible to differentiate ! between the distribution of the components; clinical I studies of herpes zoster indicate that all three may, participate. !

The distribution of nerves supplying the tympanic,! membrane is very much like that of the arteries— ' small, peripheral contributions supplying the mar-, gins of the membrane while the primary nerves^ descend from the superior aspect of the membrane and parallel the course of the external descending artery, tending to lie slightly posterior to the vessel. The pars tensa of the membrane is not particularly well supplied with sensory nerves; in contrast, t h e pars flaccida has an extremely rich innervation. >

I

The Middle Ear

Morphology \

i i

The middle ear, or tympanic cavity, is an irregu-l

larly shaped chamber lying within the temporal bone, i bounded laterally by the squamous and tympanic) portions and medially by the petrous portion. Its-greatest dimensions are in the anteroposterior and j

vertical planes, which measure approximately 15 mm . each, while the transverse diameter (between the I medial and lateral walls) varies with location and i ranges from 2 to 6 mm. It is not a confined space but communicates anteriorly with the nasopharynx i

; Pertinent Anatomy 9

i

FIGURE 1 - 4 . Innervation of the external ear.

through the auditory tube and posteriorly with the

mastoid antrum and air cells.

The middle ear can be divided into the tympanic

cavity proper, which is that portion situated medial to

the tympanic membrane, and the epitympanic recess, the upward extension of the tympanic cavity proper

above the level of the tympanic membrane.

The lateral wall (membranous wall) of the middle

ear is formed for the most part by the tympanic

membrane. Superiorly, within the epitympanic re­

cess this wall is formed by a plate of bone (the

scufwrn) derived from the squamous portion of the

temporal bone. The head of the malletfe and the

body and short process of the incus lie in the epitym­

panic recess.

The roof (tegmental wall) of the middle ear consists

of a thin plate of bone, the legmen tympani, which

separates the epitympanic recess from the cranial

cavity. It is traversed by the petrosquamous suture,

which persists into adult life in approximately 50%

of the population, and by small foramina that trans­

mit nerves and arteries.

The j'oor (jugular wall) is a very narrow, irregular

surface lying slightly below the level of the meatus,

trically arranged fibers that are most prominent peripherally, where they thicken to form a fibrocartilage ring or annulus, attaching the membrane to the tympanic sulcus of the tem­poral bone.

3 An inner layer of mucous membrane continuous with that of the middle ear cavity.

10 Pertinent Anatomy

subiculum and is the site of the cochlear window (round window), in which the secondary tympav.c membrane (round window membrane) resides, lie round window and associated membrane may or may not be visible, depending upon the size a."id configuration- of the promontory and subiculum.

3. The tympanic sinus, occupying the midc ie depression formed by the subiculum and ponticuf is at the junction of the posterior and medial walls. T> ie extent of the sinus is variable; it may extend fir enough into the petrous portion of the temporal bone to bring it into close relationship to the ampl 1-lary end of the posterior semicircular canal and tl e posterior end of the lateral canal.

4. The fossula fenestrae vestibuli (fossa of the oVil window or "stapes niche"), lying in the superk r depression above the ponticulus. It contains the vestibular (oval) window, which is closed by the footplate of the stapes and the associated a n n u k r ligament.

5. A slight bony ridge, the prominence of the latere I semicircular canal, which lies high on the posterior aspect of the medial wall in the region of the aditu;. and marks the anterior end of that component of the inner ear. ,

6. The prominence of the facial canal, lying above thr\ posterior edge of the promontory and the oval win-' dow, immediately below and parallel to the promi­nence of the lateral semicircular canal. It runs almost horizontally across the posterior half of the medial wall, then turns to enter the posterior wall. The facial nerve courses through this canal.

7. The cocWfnri/orm process, located anterosuper-iorly on the medial wall. It represents the curved end of the bony semicanal of the tensor tympani muscle.

The Ossicles

The ossicles form an articulated bony chain that I extends across the middle ear and connects the tympanic membrane with the vestibular window. This chain acts as a bent lever to convert the vibra­tions of the tympanic membrane into intensified thrusts of the stapes against the perilymph.

Developmentally, the ossicles arise from three different sources. The first branchial arch of the embryo (mandibular arch) gives rise to the head of the malleus and the long and short process of the incus; the second arch (facial arch), to the long process of the incus and the stapes. The anterior process of the malleus develops independent of the branchial arches as a membranous bone.

and is formed by a plate of bone separating the cavity f rom the bulb of the internal jugular vein. If the bulb of the vein is small, the floor may be as much as 8 to 10 mm thick and may contain hyporympanic air cells. In contrast, a large bulb may cause the floor to b u l g e upward into the middle ear. In such cases the floor may be imperfect, and the vessel and cavity are separated only by the mucosa of the middle ear.

The anterior wall (carotid wall) is a very thin, bony septum separating the middle ear from the carotid c a n a l . Perforations in the plate allow the transmission of nerves and vessels from the canal to the middle ear . Above this is the site of the opening of the semicanal for the tensor tympani muscle, and immedi­ately inferior to this is the tympanic ostium of the auditory tube, through which the middle ear com­municates with the nasopharynx.

The posterior wall (mastoid wall) (Fig. 1-5A) is somewhat triangular, with the narrowest portion s i t u a t e d inferiorly where it is related to a number of tympanic air cells. Superiorly, at the level of the epitympanic recess, the posterior wall is deficient and forms the aditus, through which the middle ear communicates with the mastoid antrum. Salient fea­tures of the posterior wall include the following:

1. The pyramidal eminence, located just below the aditus. At the apex of the eminence is a small a p e r t u r e that transmits the tendon of the stapedius muscle.

2. The iter chordae tympani posterior, a small fora­m e n immediately lateral to the pyramidal eminence. Through this foramen the chorda tympani nerve e n t e r s the middle ear.

3. The posterior sinus, a small fossa just above the p y r a m i d a l eminence.

4. The fossa of the incus, situated just above the p o s t e r i o r sinus. This marks the point of attachment of the posterior ligament of the incus.

T h e medial wall (labyrinthine wall), which sepa­rates t h e middle ear cavity from the inner ear, is the m o s t complex of the middle ear boundaries. Its major features are shown in Figure 1-5B:

1. The promontory, a slight elevation formed by ' h e basal turn of the cochlea of the inner ear. Ex­tending inferiorly and posteriorly from the promon­tory is a slight ridge, the subioiium. More superiorly, r u n n i n g from the posterior aspect of the promontory t oward the. pyramidal eminence, is a second ridge, ' h e ponticulus. The subiculum and, the ponticulus crea te three small depressions on the posterior part o f the medial wall.

2 T h e fossula fenestrae cochleae (cochlear fossa or round window niche), which is posteroinferior to the Promontory. The lowest of the three depressions of l h e medial wall, it is bounded superiorly by the

Pertinent Anatomy

The major features of the malleus include the

allowing (Fig. U6A):

I A relatively large and heavy head lying within the

epitympanic recess, which bears on its surface a

small facet for articulation with the incus.

> A short, somewhat constricted neck from which

three processes arise, including:

A. The long and prominent manubrium, the largest

of the mallear processes. It is attached to the

tympanic membrane and in turn is the site of

insertion of the tensor tympani muscle.

B. The lateral process, which creates the mallear

prominence of the tympanic membrane.

C. The anterior (long) process, a long and delicate bony projection in the fetal malleus. In the

adult it is a small bony stump that is the site

of attachment of the anterior ligament of the

malleus.

The malleus is suspended by three small ligaments

Fig 1-6B), which include the anterior mallear liga-nent, extending from the anterior process to the

vmpanosquamous fissure; the superior mallear liga-nent, extending from the top of the head to the roof

jf the epitympanic recess; and the lateral mallear igament, which runs from the lateral process to the

•nargin of the tympanic notch.

Also associated with the malleus is the tensor

ympani muscle. This muscle arises from the cartilag-

nous part of the auditory tube, the adjacent sphe-

loid bone, and the semicanal situated directly above

•he osseous portion of the auditory tube. Its tendon

)f insertion passes through the cochleariform proc-

!ss, turns sharply lateral, and inserts on the manu-

>rium of the malleus, close to the neck. The muscle

icts to draw the manubrium medially, tensing the

ympanic membrane, and thus serves a protective

Hinction. The tensor tympani is innervated by a

'ranch of the mandibular division of the trigeminal

l erve .

The mews (Fig. 1-6C) is characterized by the follow­

ing features:

'•• A relatively large body that is deeply indented

anteriorly to form an articular facet.

•• Two bone processes. These include:

A The sliort process, which extends posteriorly

from the body.

B. The slender long process, extending inferiorly

from the body and paralleling the manubrium

of the malleus. On the medial side of the very

distal extremity of the long process is the small

lenticular process, through which the incus ar­

ticulates with the stapes.

Like the malleus, the incus is suspended by small

5'irnents (Fig. I - 6 D ) . These are the posterior ligament,

"Kh acts to hold the short process in the fossa of

the incus, and the superior ligament, which extends '<

from the body to the roof of the epitympanic recess.';

The stapes (Fig. l - 6 £ ) consists of the following:

1. A small, cylindrical head, which articulates with

the lenticular process of the incusT *

2. Two crura (anterior and posterior), which ex­

tend from the head. The anterior c m s is somewhat

shorter and straighter than the posterior.

3. A thin base (footplate), a flattened plate of bone 1 .

attached on its end to the distal extremities of the-

crura. It fits into the vestibular window and, like thatt

structure, has a straight inferior border and a curved^

superior border.

The ligamentous support of the stapes is through;

the elastic annular ligament, which attaches to the)

margins of the footplate and the vestibular window

and allows movement of the stapes. Such movement

is greatest at the anterior end and upper border of

the footplate and very slight posteroinferiorly. It has

been stated that loud tones change the normal pat­

tern of movement to a rocking motion; this would

result in a net decrease in the displacement of peri­

lymph, thereby protecting the inner ear. This change

presumably is brought about by contraction of the

stapedius muscle (Fig. 1-6F) , which inserts onto the

posterior crus. As mentioned above, this muscle

serves a protective function by preventing excessive

excursion of the footplate; it does not move the

ossicle unless the ossicular chain is broken. It is

innervated by a branch of the seventh nerve.

The joints of the ossicular chain are true synovial

(diarthrodial) joints with characteristic articular cap­

sules. There are two such joints within the chain.

The first is the incudomalleal, between the head of the

malleus and the body of the incus. This is a relatively

lax joint that allows the movement of the incus to

lag behind that of the malleus; as a result, the

amplitude of the movement of the bony process of

the incus is less than that of the manubrium. The

second joint is the incudostapedial, between the lentic­

ular process of the incus and the head of the stapes.

The Auditory (Pharyngotympanic

or Eustachian) Tube

The auditory tube extends from its tympanic os­

tium within the anterior wall of the middle ear cavity

to its pharyngeal ostium within the nasopharynx.

The latter is situated just posterior to the dorsal end

of the inferior nasal concha. In the adult the tube is

between 30 and 40 mm in length, and has a slight

S-shaped configuration as it passes obliquely down-

14 Pertinent Anatomy

w a r d , medial, and anterior from the middle ear to t he pharynx. The tympanic ostium is roughly 25 mm higher than the pharyngeal ostium in the adult. There are some basic and significant morphologic differences between the auditory tube of the child a n d that of the adult; in the child the tube is shorter a n d relatively wider and more horizontally situated.

Structurally, the auditory tube consists of both cartilaginous and bony components . The bony por­tion makes up approximately two thirds of the tube; jt is widest at the tympanic orifice and gradually narrows throughout its length, with its anterior ex­tremity (the isthmus) the most constricted portion of t he entire tube. In its course the bony tube is lateral to the carotid canal, superior to the jugular fossa. The cartilaginous portion of the tube extends from t he isthumus to the nasopharynx. It is not totally cartilaginous, however; its lower lateral and inferior w a l l s consist of fibrous connective tissue overlying t h e tensor and levator veli palatini muscles.

The lumen of the auditory tube, in the resting state, is a closed, slitlike cavity. The pharyngeal end of the tube strongly resists passage of air from the pharynx to the middle ear. Passage from the tym­panic cavity to the pharynx is much easier.

The Mucosal Lining of the

Middle Ear

The tympanic cavity is lined throughout hv a thin, transparent, vascular membrane that is continuous wi th that of the auditory tube anteriorlv and the tympanic antrum and mastoid cells posteriorly. The membrane is tightly bound to the periosteum and a l s o invests the ossicles and their associated liga­ments. In reflecting Irom the walls ol the cavitv to the ossicles and their ligaments, the mucous lining forms various folds and pouches; the most important of these are the superior vouch (Prussak's pouch), situated medial to the pars flaccida of the tympanic membrane, and the anterior and posterior vouches (of Troltsch), which are related to the anterior and pos­terior mallear ligaments respectively.

Vascular Elements of the

Middle Ear

The middle ear receives blood via a number of small arteries (Fig. 1 -7 ,4 ,6 ) , which with one excep­

tion are derived from the external carotid c its branches. They include;

1. The anterior tympanic, a branch of the maxillary artery. It is distributed to the anterior part oi the cavity, including the medial surface of the tympanic membrane, and enters the middle ear by parsing through the petrotympanic fissure.

2. The stylomastoid branch of either the posterior auricular or occipital artery. This artery enters the facial canal and gives rise to the posterior lyn panic artery, which then enters the middle ear in corroany with the chorda tympani nerve.

3. The inferior tympanic artery, derived frorii the ascending pharyngeal branch of the external carotid. It accompanies the tympanic branch of nerv? IX through the tympanic canaliculus to gain the middle ear cavity.

4. The superficial petrosal and superior tympanic^ ar­teries, which are both branches of the middle mr nin-geal artery. The former runs through the facial canal for a short distance, then pierces the tegmen tym, >ani to enter the middle ear; the latter enters through the petrosquamous fissure.

5 . The atroficutympitmc arteries arise from the i t ter-nal carotid as it passes through the carotid canal; and enter the middle ear by passing through the thin bony lamina separating the carotid canal from the middle ear.

The veins of the middle ear parallel the arteries. TUey are tributary to the superior petrosal dural sinus m e t the pterygoid plexus of veins.

Nerves of the Middle Ear \\ ( R R . U

The major nerve of the middle ear is the lumpttmc

1'iathh vt the gU^>ophan,nytvl iicnr (Jarobson's nerve}. Arising (rom the inferior ganglion of the parent trunk, the tvnipanic nerve enters the tvmpanic catn-aliculus through a small foramen located on the crest of the thin plate of bone separating the juguhr foramen and the external orifice of the carotid cam I. Once in the middle ear, the nerve forms the tympanic

plexus within the mucosa overlying the promontor /. There are two modalities represented in the tympanic nerve/plexus. The greatest portion of the fibers a e sensory; these are distributed to the mucosa of t i e middle ear, the mastoid air cells, and the audito'y tube. The remaining fibers are parasympathetic and have no function in the middle ear. Instead, they emerge from the upper border of the plexus to pierce the tegmen tympani and run forward on the floor of

Pertinent Anatomy 15

FIGURE 1-7 A-B, Arteries of the middle ear.

Sup. tympanic Petrosal

\d Pertinent Anatomy

Greater petrosal Geniculate ganglion

FIGURE 1-8. Nerves of the middle ear.

Caroticotympanic

the middle cranial fossa as the lesser petrosal nerve; ultimately they leave the skull to run with the auric­ulotemporal branch of V3 and supplv the parotid gland .

1 he middle ear receives sympathetic fibers derived

from the internal carotid plexus. These fibers, which e n t e r the middle ear along with the caroticotympanic

ar te r ies , are primarily associated with the vessels of

we cavity and have a vasoconstrictive effect.

T h e chorda tympani branch of the facial nerve enters

he middle ear through the iter chordae posterius.

Passes forward and down between the manubrium

' *e malleus and the long process of the incus,

nen leaves the cavity by passing through the petro­

tympanic suture. The chorda tympani has no func-

°n in the middle ear. It contains both parasympa-

J l i c fibers supplying the submandibular and

' "lingual glands and taste fibers for the anterior 0 th .rds of the tongue. After leaving the middle

ear it joins the lingual branch of V3 to be distributed with that nerve.

Although they do not enter the middle ear, the nerves to the muscles associated with the ossicles must be mentioned since they are vital to normal function. The nerve to the stapedius muscle is a branch of the facial nerve, and arises from the parent trunk as it descends through the vertical portion of the osseous facial canal. The nerve to the tensor tympani is a branch of the mandibular division of the trigeminal nerve.

Pneumatization of the Temporal Bone

The temporal bone exhibits varying degrees of

pneumatization. Because of the intimate relationship

of the middle ear to these areas, a basic appreciation of the location and extent of pneumatized areas is desirable.

Since the mastoid process develops from both petrous and squamous portions of the temporal bone, there is a sutural line between the two com­ponents that normally is obliterated with growth. Occasionally, however, a heavy plate of bone persists between the two portions, forming what has been designated [Corner's septum or the "false bottom." The existence of this septum can cause confusion in surgical approaches through the mastoid process.

The mastoid process is rather consistently pneu­matized (80%), the process usually being completed by the third or fourth year. There is, however, considerable variation both in its extent and in the arrangement of the air cells. Because of this variation, several types are described, including the pneuma­tized, in which the entire process is occupied by air cells; the diploic, in which the process is occupied by bpne marrow instead of air cells; the mixed type, consisting of a combination of the pneumatized and diploic types; and the sclerotic or nonpneumatized/ nondiploic process. Owing to the considerable vari­ation in the extent and location of the mastoid cells, several terminologies have been used. The position of the sigmoid sinus in the posterior cranial fossa will influence markedly the position or occurrence of all types.

Mastoid air cells may invade adjacent areas of the temporal bone. Some of the more frequent extensions form the hy\iotympanic cells, which lie in the plate of bone separating the middle ear cavity from the jug­ular bulb, and the epitympanic cells, which are exten­sions into the roof of the middle ear. The latter group may be extensive enough to include cells that will invade the root of the zygomatic arch and the squa­mous portion of the temporal bone.

The petrous apex of the temporal bone (i.e., that part of the petrous portion anterior to the labyrinth) may also be pneumatized, particularly by outgrowths from the tympanic cavity. These cells, the petrous apex cells, are necessarily related to the auditory tube and the carotid canal.

The Facial Nerve in the

Temporal Bone

After traversing the internal acoustic meatus and

passing through the lateral end of that structure, the

facial nerve enters the bony facial canal (fallopian

canal). This canal continues laterally for a short

Pertinent Anatomy 17

The Inner Ear

The inner ear containing the essential cochlear and

vestibular mechanisms, lies within the petrous por­

tion of the temporal bone. The labyrinth of the inner

ear is surrounded by the bony otic capsule, which is

a unique structure for several reasons. It is formed

from 14 separate centers of ossification that fuse,

leaving no sutural lines. These centers, though

formed from cartilage, retain no areas of chondral

growth. In addition, the bone of the capsule retains

its fetal character, that is, typical haversian systems

I* distance and brings the facial nerve to just above the

base of the cochlea, where it makes a sharp turn (the

external genii) to run posteriorly. The genu is also the

site of the. geniculate ganglion of the nerve, which

contains the cell bodies of the nerve's sensory com­

ponents. The genu and the ganglion are anterolateral

to the superior semicircular canal and between the

vestibule of the inner ear and the cochlea, and can

be easily localized from the middle ear as a point

situated just medial to the tip of the cochleariform

process. Continuing posteriorly with a slight infero-

lateral inclination, the bony canal forms the promi­

nence of the facial canal on the medial wall of the

middle ear. This prominence may be large enough

to partially cover the oval window and the base of

the stapes. The lateral wall of the canal in this part

is extremely thin and may be dehiscent. Behind the

base of the pyramidal eminence the canal makes a

broad turn to descend vertically and somewhat lat­

erally through the mastoid process. In this descend­

ing or vertical portion the nerve may have a slight

anterior concavity. Relative to the exterior of the

skull, the canal normally lies deep to the sutural

groove between the tympanic and mastoid portions

of the temporal bone. It should be remembered that

there may be marked deviation from this "normal"

position, in which case the canal is usually situated

more posteriorly.

In its course from the brainstem through the facial

canal the facial nerve is supplied with blood by small

arteries derived from the anteroinferior cerebellar

branch of 4he basilar artery, the stylomastoid or

occipital branches of the external carotid, and the

petrosal arteries. There are apparently no anasto­

moses b e t i e e n the labyrinthine blood supply and

these arteries, which seem to anastomose freely with

one another. Insufficiency of the vascular supply to

the facial nerve, from whatever cause, is regarded

by some as one of the primary causes of Bell's palsy.

18 Pertinent Anatomy

never develop. Finally, the capsule's maximum di­mensions are attained by the fifth week of intrauter­ine life.

The labyrinth of the inner ear is divided into osseous and membranous components. The osseous

labyrinth, a system of bony canals within the otic capsule, consists of three parts: 1. The vestibule, which forms the central portion of

the labyrinth; it is a relatively large, ovoid space

approximately 4 mm in diameter. Its characteristic features include the following:

A. The elliptical recess, located on the floor of the vestibule. It receives the anterior end of the utricular portion of the membranous labyrinth.

B. The spherical recess, located anterior and slightly inferior to the elliptical recess. It is the site of the saccular portion of the membranous labyrinth.

C. The •vestibular whitlow, within the lateral w,.ll of the vestibule.

D. Small orifices for the passage of nerves to the vestibular portion of the inner ear. These a e found on the medial wall and adjacent flo-•, where the vestibule abuts on the lateral e r d of the internal acoustic meatus.

2. The semicircular canals, which are continuous with the vestibule. The anterior (superior) canal forms the arcuate eminence on the bonv floor of the middle cranial fossa. The posterior'canal has no externally located landmarks associated with if. Ihe lateral canal, as mentioned above, creates ,i

prominence in the region of the aditus of th.-middle ear. All of the semicircular canals com municate with the vestibule through both of thei-crura. There are only five openings into the ves tibule, however, since the posterior crus of th.

Pertinent Anatomy 19

anterior canal and the superior crus of the poste­rior canal unite to form a single crus.

The canals have very definite planes of orien­tation. The anterior is situated in the vertical plane at an angle of 45 degrees with respect to the sagittal plane of the skull, the posterior crura being more medial. The posterior canal is also in the vertical plane, at 45 degrees with respect to the sagittal plane of the skull (that is, at 90 degrees with respect to the plane of the anterior canal). The lateral canal forms an angle of approximately 30 degrees with the horizontal plane, its anterior end being highest, and is situated in the angle between the anterior and posterior canals.

3. The cochlea, a cone-shaped, hollow, bony spiral of about two and three quarters turns with a rela­tively broad base and a pointed apex or cupula. Its base lies against the anteromedial surface of the vestibule and the lateral end of the internal auditory meatus. Part of the basal turn of the cochlea forms the promontory of the middle ear.

• From its base the axis of the cochlea is directed anterolaterals/ and slightly upward.

The central bony core of the cochlea is the modiolus, through which nerves and vessels travel to attain the structures of the cochlea. From the outer surface of the modiolus the osseous spiral

lamina projects into the cavity of the cochlea, partially subdividing the duct. It terminates at the cupular end of the cochlea by projecting slightly beyond the apex of the modiolus. This projecting bony process of the lamina is the hamulus.

By convention, and for ease of reference and description, the cochlea is described as if it were sitting on its base with the apex pointing directly up. Viewed in this orientation, it can be seen that the spiral lamina is initiating the division of the cochlear duct into an upper chamber, the scala

vestibuli, and a lower chamber, the scala tympani.

Only the scala vestibuli communicates with the vestibule of the inner ear; it also communicates with the scala tympani at the apex of the duct. The scala tympani ends blindly at the round window (secondary tympanic membrane) of the middle ear.

The osseous labyrinth is not a closed chamber; there are several areas of communication with the exterior. These include the following:

1. The vestibular aqueduct, extending through the otic capsule from the vestibule to the posterior cranial fossa. Its cranial end lies lateral to the internal acous­tic meatus on the posterior surface of the petrous portion of the temporal bone, where it is usually overlaid by a scale of bone. This aqueduct trans­mits the endolymphatic duct and an accompanying vein.

2. The cochlear aqueduct, which begins in the scala tympani of the basal coil of the cochlea near the round window. This small canal terminates on the inferior surface of the petrous pyramid, between the jugular fossa and the external orifice of the carotid canal. In the human it is not patent, being filled with connective tissue.

3. The oval window, which is closed by the foot­plate of the stapes and the associated annular liga­ment.

4. The round window, closed by the secondary tympanic membrane.

5. The fissula ante fenestram and the fossula post

fenestram, small clefts related to the vestibular win­dow of the lateral wall. The fissula ante fenestram usually extends completely through the bony lateral wall of the vestibule, while the fossula does so in only about 25% of all individuals. Both normally are filled with connective tissue. The fissula is important because of its predilection for otosclerotic bone for­mation.

6. The orifices of the nerves and vessels attaining the inner ear.

Lining the entire osseous labyrinth is a layer of periosteum or endosteum, which is continuous with the periosteum of the cranium through the various apertures and lies in close apposition to the walls of the osseous labyrinth. The areas of modification that merit further description occur within the cochlea. At the free edge of the osseous spiral lamina the endosteum is thickened to form the limbus, which then divides into vestibular and tympanic lips sepa­rated by a groove, the internal spiral sulcus. The vestibular lip is confluent with the vestibular mem­brane. The tympanic lip extends from the edge of the osseous spiral lamina across the lumen of the cochlea to the opposing peripheral wall, forming the fibrous basilar membrane. It attaches peripherally to the crest of the spiral ligament, which in turn is an area of thickened, modified endosteum overlying the lateral wall of the cochlea. While the basilar mem­brane divides the lumen of the cochlea, it does not extend all the way to the cupula but terminates just before it, leaving a small area of communication termed the helicotrenm between the scala vestibuli and the scala tympani.

The membranous labyrinth is a system of delicate, epithelium-lined channels surrounded by connective tissue and lying within the osseous labyrinth (Fig. 1-9) . Like its osseous counterpart, the membranous labyrinth has vestibular, semicircular, and cochlear components that communicate with one another. The membranous labyrinth exhibits certain general fea­tures:

1. Its luminal capacity is much less than that of the osseous labyrinth.

pO Pertinent Anatomy

is the most highly modified. Situated within the bony cochlea, where it lies upon the upper surface of the basilar membrane, it is a triangular duct extending, the full length of the basilar membrane (but not to the apex of the cochlea). Basally it is continuous with the saccule through the ductus reuniens. The three basic structural components of the cochlear due include the following:

1. The vestibular membrane, which forms the roo, of the cochlear duct and separates the endolymphatic space of the duct from the perilymphatic space oi the scala vestibuli. It is an extremely thin membrane (approximately 0.003 mm).

2. The lateral wall, consisting of the sfrin vascularis,

a highly vascular region situated on the inner surface of the spiral ligament. As its name implies, it is characterized by its highly vascular nature and is generally believed to be the source of endolymph.

3. The floor, consisting of the organ of Corti, which is the sensory organ for hearing.

The Sensory Receptors of the Inner Ear

Within the vestibular portion of the inner ear the receptors consist of the following:

1. The cristae, located within the ampullae of thr membranous semicircular canals. They consist oi thickened epithelium containing neuroepithelial hai; cells. Overlying the epithelium and extending to the opposite wall of the ampulla is the gelatinous cupula.

The cilia of the hair cells project into the base of the cupula.

2. The maculae, which are located in the utricle and saccule and have similar structures. The hair cells of the neuroepithelium are stiff, nonmotile pro­jections embedded in an overlying gelatinous mem­brane, the statoconic or otolithic membrane. This mem­brane is unique in that it contains numerous crystals termed otoliths.

The sensory portion of the cochlear duct, the organ

of Corti or spiral organ, has the same basic structure

as the cristae and maculae. It lies upon the basilar

membrane and consists of supporting cells and hair

colls overlaid by a gelatinous tectorial membrane. The

supporting cells are of several different types; how­

ever, all contain fibrils within their cytoplasm, and

their free edges form a reticular membrane against

which the tectorial membrane rests. The most im­

portant of the supporting cells are the phalangeal cells,

arranged in a single inner row, and an outer group

consisting of three to five rows depending on the

Pertinent Anatomy 21

level of the cochlea under consideration, there being

more rows apically than basally. The inner row is

associated with a single row of hair cells, while the

outer group has phalangeal cells alternating with

rows of hair cells. Between the inner and outer group

of phalangeal cells is an intercellular space extending

the entire length of the spiral organ and termed the

tunnel, inner tunnel, or canal of Corti. It is bounded

by special supporting cells designated the inner and

outer pillars (Corti's rods). Together the pillars and

the canal form Corti's arch. Peripheral to the phalan­

geal cells are other supportive elements, the tall cells

of Hensen and the shorter, more peripherally located

cells of Claudius.

The hair cells of the spiral organ have numerous

"hairs" projecting from their reticular surface (40 to

100 per cell). The innermost of these cells are long

and are thought to be the least sensitive to sound.

In contrast, the outer hair cells are short, being

wedged between the apical portions of the phalan­

geal cells.

able variation in the pattern of branching of the

labyrinthine artery. Any one of the normal branches

may be missing or may arise via a common trunk

with another branch.

Descriptions of the venous drainage of the inner

ear conflict. In all probability most are accurate,

reflecting a considerable but normal variation. The

described patterns include the following:

1. A vein of the vestibular aqueduct, draining most

of the semicircular canals and emptying into either

the sigmoid or the inferior petrosal dural sinus.

2. A vein of the cochlear aqueduct, draining the entire

cochlea and vestibule. It runs in a long canal paral­

leling the cochlear aqueduct to enter the superior

bulb of the internal jugular vein or the inferior

petrosal dural sinus.

3. A labyrinthine vein, which seems to be inconsis­

tent. When present, it drains the apical and middle

coils of the cochlea and traverses the internal acoustic

meatus to become tributary to the inferior petrosal

dural sinus.

Vascular Supply of the Inner Ear

The primary source of blood to the inner ear is the Inbi/riiiHiine (internal auditory) artery. While this vessel is usually described as originating from the basilar artery, it probably arises more frequently from the anterior inferior cerebellar artery. In addition, it may be duplicated by terminal branches that arise independently to enter the internal acoustic meatus.

In its course the labyrinthine artery accompanies nerves VII and VIII through the internal acoustic meatus. Its main branches run in the endosteum of the labyrinth, and small branches traverse the tra­b e c u l e to gain the membranous labyrinth. Appar­ently there are no functional anastomoses between these two areas of distribution.

The most common first branch of the labyrinthine artery is that which is distributed to the utricle, part of the saccule, and the anterior ends of the anterior and lateral semicircular canals. This branch has been called both the anterior vestibular and vestibular artery.

When there is an apparent doubling of the labyrin­thine artery, it is this branch that most frequently arises independently. The other two common branches of the labyrinthine artery are the vestibulo­

cochlear (posterior vestibular) artery, which is distrib­uted to the saccule, the posterior semicircular canal and parts of the anterior and lateral canals, part of the utricle, and the entire basal coil of the cochlea; and the cochlear nrlcry, which is distributed to the remaining portion of the cochlea. There is consider-

Nerves of the Inner Ear

Before describing the innervation of the inner ear we will consider the fundus of the internal acoustic meatus. The fundus is divided into superior and inferior portions by a horizontal bony ridge termed the transverse crest. Located posteriorly within the smaller superior depression are a number of small foramina that transmit the nerves to the utricle and the ampullae of the anterior and lateral semicircular canals. This is the superior vestibular area. Anteriorly within the upper depression is a relatively large foramen that transmits the facial nerve. In the larger inferior depression, immediately under the posterior end of the transverse crest, is the inferior vestibular

area, which contains small foramina transmitting the nerves to the saccule. Below and slightly posterior to the inferior vestibular area is the foramen singulare,

through wiiich nerves pass to gain the ampulla of the posterior semicircular duct. Anteriorly the infe­rior depression is occupied by the foraminiferous spiral

tract, a series of minute foramina arranged in spiral fashion that appose the base of the cochlea and the modiolus. At the center of the spiral is the somewhat larger orifice of the modiolar canal.

The nerve of the inner ear is the vestibulocochlear

(statoacoustic, acoustic, or auditory) nerve. Function­ally, it consists of two divisions:

1. The vestibular division, containing fibers arising from the vestibular ganglion, a sensory ganglion situ­ated at the lateral end of the internal acoustic meatus.

''• 1. The membranous labyrinth tends to be placed peripherally within the osseous labyrinth; it is sur-jounded by the perilymphatic space (and perilymph). In most locations this space is traversed by numerous (Jelicate trabeculae extending from the endosteum to £e membranous labyrinth. The exception to this is in the cochlea, where the trabeculae are very much (educed or absent.

3. The membranous labyrinth contains the recep-jpts for hearing and equilibration.

4. It is a self-contained system with no patent communication with other areas.

5. The membranous labyrinth contains endo­lymph.

Individual Components of the Membranous Labyrinth

The vestibular portion of the membranous laby­rinth is characterized by two large dilatations, the Hfricfe and saccule. The utricle, located in the posterior portion of the osseous vestibule, receives the crura of the three membranous semicircular canals. From its anterior end arises the minute utricular duct

through which it communicates with both the en­dolymphatic duct and the saccule. Situated within the utricle on its floor and lower lateral wall is the macula, one of the receptor sites of the vestibular system. The saccule is located anteromedial to the utricle within the osseous vestibule. From its poste­rior aspect arises the small saccular duct that is contin­uous with the utricular duct (hence, utriculosaccular)

and the endolymphatic duct. Anteriorly the saccule is continuous with the cochlear duct through the extremely small ductus reuniens. The saccule has a macula located on its lateral wall.

The endolymphatic duct arises from the union of the utricular and saccular ducts and passes through the vestibular aqueduct to terminate in a blind dilatation, the endolymphatic sac, within a dural cleft on the medial surface of the petrous portion of the temporal bone. Within the sac are extensive folds of epithelium with cores of vascular connective tissue, which would seem to indicate that this particular site is the region "'greatest physiologic activitv.

The membranous semicircular canals conform closely to the configuration of their osseous counterparts. At the anterior ends of the anterior and lateral canals a nd at the posterior (inferior) end of the posterior canal are prominent dilatations or ampullae, which house the receptor sites (cristae).

The cochlear portion of the membranous labyrinth

22 Pertinent Anatomy

These sensory fibers form the superior and inferior

vestibular n e w s . The superior vestibular nerve sup­

plies the ampullae of the anterior and lateral semicir­

cular canals plus the maculae of the utricle and

saccule. Hence, it is this nerve that enters the inner

ear through the superior vestibular area of the fundus

of the meatus. The inferior vestibular nerve supplies

the ampulla of the posterior semicircular canal and

the macula of the saccule. It is associated with the

inferior vestibular area and the foramen singulare of

the meatal fundus.

2. The cochlear division, consisting of fibers arising

from the spiral ganglion, which is situated in the coils

of the modiolus at the base of the osseous spiral

lamina. These fibers pass through the lamina to gain the organ of Corti. Within the internal meatus these fibers are associated with the foraminiferous spiral tract and orifice of the modiolar canal.

Associated with the nerves of the inner ear is the bundle of Oort, a small number of efferent fibers arising from the superior olive of the brainstem. These fibers run from the brainstem to the inner ear within the inferior vestibular nerve, then pass ovet to join the cochlear nerve. Although it is assumed that these fibers are distributed primarily to the cochlea, where they may play a part in some sort of feedback mechanism, their exact function has yet t•;• be determined.

CHAPTER 2 Pertinent Histology

This short chapter presents four photomicro­graphs of horizontal temporal bone sections at dif­ferent levels. The sole purpose is to provide a general orientation in terms of temporal bone anatomy; these sections are useful in achieving the three-dimensional visualization necessary for temporal bone surgery. A detailed description of horizontal temporal bone sec­tions is beyond the purpose of this atlas. The hori­zontal sections are also to be used as references for

the pertinent! histopathologic slides described in this

book, which* for practical reasons are included in

their specific chapters rather than grouped together

here.

When describing horizontal sections of temporal

bones, "superior" means cephalad; "inferior" is cau-

dad; "anterior" is ventral; "posterior" is dorsal; "lat­

eral" is toward the external ear canal; and "medial"

is away from' the external ear canal.

24 Pertinent 1 listology

FIGURE 2 - 1

This section is in the area of the epitvmpamim It

is important to remember that the middle car cavitv

extends superiorly above the tympanic membrane It

is at this level that the malleus can be laterally fixed

(not shown in this section). The wide communication

between the middle earand mastoid can be observed

as can the close proximity of the incus and horizontal

(lateral) semicircular canal to the aditus and antrum

At this high level the tensor tympani occupies the

anterior wall and is in close proximity to the facial

nerve (FN), which is surrounded by a thin plate of

bone that is sometimes dehiscent. It is also important

to recognize the thinness of the bone plate separating the vestibule from the internal auditory canal (pnrall'c'

«r,vw>). I his must be kept in mind when doing .-/abyrinthcctomy, since it is very easy to accidentally create a fistula with subsequent cerebrospinal fluir leak during this procedure. Note in these section-the air space that exists in the normal mastoid cavity compared with that in temporal bones with otitr media (see Chapter 1 0 ) .

At this higher level, the nerves of the internal

auditory canal are the facial nerve anteriorly and the

superior division of the vestibular nerve posteriorly.

Pertinent Histology 25

FIGURE 2 - 2

This section is at the level of the stapes footplate,

which is bound to the oval window by the annular

ligament. The short distance from the footplate to

the contents of the vestibule (utricle and saccule)

should be noted. There is very little room ( 1 . 5 to 2 . 0

mm) to work with a Hough hoe (or similar instru­

ment) when removing the footplate without touching

vestibular structures. At this level the FN is located

posterior to the oval window; dehiscence (sometimes

bulging) is not uncommon at this site. This should

be remembered when working in this area.

This section also provides guidance for placing

tubes in the superior quadrants of the tympanic

membrane. The risk of damaging the incus or leaving

it directly exposed to the exterior by placing a tube

in the posterior superior quadrant is obvious in this

section; the safe placement in the anterosuperior

quadrant is more evident in Figure 2 - 3 .

The tendon of the tensor tympani can be observed

inserting^laterally over the anteromedial surface of

the manubrium of the malleus. It is here that the

tendon of the tensor tympani is sectioned (when this

procedure is needed). The body of the incus is

reduced in diameter at this level to form the body of

the descending long crus (long process of the incus).

The posterior incudal ligament can be observed as it

attaches at the fossa of the incus (fossa incudis). At

this level the nerves of the internal auditory canal

are the cochlear nerve anteriorly and the inferior

division jf the vestibular nerve posteriorly.

26 P e r t i n e n t H i s t o l o g y

F I G U R E 2 - 3

I n th i s s e c t i o n t h e e x t e r n a l e a r c a n a l a n d t y m p a n i c s h i p b e t w e e n t h e p o s t e r i o r s e m i c i r c u h r c a n a l ™ H

t h e th in p l a t e of b o n e t h a t s e p a r a t e s b o J s t r u c t u r e s m i c o ^ r X"̂ Xet ° *

A n i m p o r t a n t f e a t u r e i n th i s s e c t i o n i s t h e r e l a t i o n -

P e r t i n e n t H i s t o l o g y 27

F I G U R E 2 - 4

A t th i s l o w e r l eve l i n t h e m e s o t y m p a n u m t h e

p r o m o n t o r y i s c l e a r l y a p p a r e n t , a s i s t h e t y m p a n i c

m e m b r a n e i n its full h o r i z o n t a l e x t e n t . T h i s s e c t i o n

p r o v i d e s a c l e a r i m a g e o f t h e m i d d l e e a r s p a c e

a n t e r i o r l y a n d p o s t e r i o r l y for p l a c e m e n t o f t u b e s i n

t h e i n f e r i o r q u a d r a n t s . T h e s i n u s t y m p a n i c a n b e

o b s e r v e d a n d t h e d i f f i cu l ty o f c l e a n s i n g i t a d e q u a t e l y

i f i t i s i n v o l v e d w i t h c h r o n i c d i s e a s e c a n be s e e n . In

t h e s e f o u r f i g u r e s t h e t h i n n e s s o f t h e m u c o p e r i o s -

t e u m s h o u W b e n o t e d a s a r e f e r e n c e for c o m p a r i s o n

w i t h t h e p a t h o l o g i c s l i d e s s h o w n i n spec i f i c c h a p t e r s .

CHAPTER 3 Pertinent Concepts in High Resolution Temporal Bone Imaging Computed Tomography and Magnetic Resonance Imaging

H i g h r e s o l u t i o n c o m p u t e d t o m o g r a p h y ( C T ) a n d

m a g n e t i c r e s o n a n c e ( M R ) i m a g i n g h a v e d r a m a t i c a l l y

e n h a n c e d t h e f ie ld o f t e m p o r a l b o n e i m a g i n g . T h i n

s e c t i o n a x i a l a n d c o r o n a l C T p r o v i d e s d e t a i l e d v i e w s

o f t h e o s s i c l e s , b o n y l a b y r i n t h , c o c h l e a , a n d m a s t o i d

a i r c e l l s ( F i g s . 3 - 1 t o 3 - 5 A ) . M R p r o v i d e s s u p e r i o r

so f t t i s s u e c o n t r a s t r e s o l u t i o n o v e r C T a n d o f t e n

e l i m i n a t e s t h e n e e d f o r i n v a s i v e p r o c e d u r e s s u c h a s

a r t e r i o g r a p h y a n d p n e u m o c i s t e r n o g r a p h y ( F i g s . 3 -

5 B t o 3 - 9 ) . T h e m u l t i p l a n a r c h a r a c t e r i s t i c s o f M R

p e r m i t d e m o n s t r a t i o n o f s o f t t i s s u e a n a t o m y i n any-

d e s i r e d p l a n e o f p r o j e c t i o n , a n d i m a g i n g p a r a m e t e r s

m a y b e a d j u s t e d t o fit e a c h p a r t i c u l a r c a s e . Thin

s e c t i o n C T i s r e c o m m e n d e d w h e n e v e r b o n y s t r u c ­

t u r e s n e e d t o b e v i e w e d i n d e t a i l . T e m p o r a l b o n e

i n j u r i e s , d e v e l o p m e n t a l a n o m a l i e s , o t o s c l e r o s i s , a n d

i n f l a m m a t o r y m i d d l e e a r o r m a s t o i d l e s i o n s a r e b e s t

s t u d i e d w i t h C T , b u t M R i s t h e p r o c e d u r e o f c h o i c e

fo r e v a l u a t i o n o f i n t e r n a l a u d i t o r y c a n a l m a s s l e s i o n s .

Vascular Ultrasound for Atherosclerosis Screening

H i g h r e s o l u t i o n r e a l - t i m e d u p l e x u l t r a s o u n d witrf.

D o p p l e r a n d s p e c t r a l a n a l y s i s i s a u s e f u l a n d c o s t -

e f f e c t i v e s c r e e n i n g p r o c e d u r e fo r c e r v i c a l c a r o t i d a t h ­

e r o s c l e r o s i s . R e a l - t i m e u l t r a s o u n d p r o v i d e s d i r e c t

v i s u a l i z a t i o n o f t h e c e r v i c a l c a r o t i d a r t e r i e s ( F i g s . 3 ¬

10 , 3 -11 ) . D o p p l e r a n d s p e c t r a l a n a l y s i s d e f i n e f l o w

p a t t e r n s a n d v e l o c i t y . T h e s e n o n i n v a s i v e s c r e e n i n g

p r o c e d u r e s a r e e a s i l y p e r f o r m e d u p o n p a t i e n t s w i t h

c o m m o n c o m p l a i n t s s u c h a s " d i z z i n e s s " o r " l i g h t ­

h e a d e d n e s s , " p r e c l u d i n g t h e n e e d f o r a r t e r i o g r a p h y

i n m o s t c i r c u m s t a n c e s . M R s h o w s i m m e n s e p r o m i s e

fo r n o n i n v a s i v e s t u d y o f t h e i n t r a c r a n i a l v e s s e l s ( s e e

F i g . 3 - 7 8 , C ) .

P e r t i n e n t C o n c e p t s i n H i g h R e s o l u t i o n T e m p o r a l B o n e I m a g i n g 2 9

FIGURE 3 - 1 . , a u M o c a n a l ( i a £ ) . v e s i i b u | e ( o p e n a m w ) . The geniculate Normal temporal bone (1.5 mm thick axial LI images, w ?°oo; • „ „ r n , , | m a l l P „ , head (lane curved arrow) and incus body

handle of malleus (curved arme); normal mastoid air cells Mule arrows).

FIGURE 3-2. , , „ Mondini deformity in a child with congenital deafness. The deformed cochlea (arrow) is globular in configuration and is con­tinuous with the deformed vestibule fourni rtrnite). Note an operative defect (ic/iilc imam) from previous exploratory surgery.

J P e r t i n e n t C o n c e p t s i n H i g h R e s o l u t i o n T e m p o r a ] B o n e J m o g i n g P e r t i n e n t C o n c e p t s i n H i g h R e s o l u t i o n T e m p o r a l B o n e i m a g i n g 3 1

FIGURE 3-5 . Intraconalicular acoustic schwan­noma shown with coronal CT (A) and MRt (R) A, There is marked expansion of the ny;ht internal au­ditory canal (arrow). 8, Expansile mass Cornue) is isointense with brain <TR = WX), TI! = 20).

FIGURH y-b.

Paraganglioma ol the temporal hone demonstrated with carotid arteriography Oronlal pru)eclion). An intense tumor blush (forge arrow*) is mh-ii within the temporal bone on this common carotid injection \'o<c cn}jrHc\l cxfcrn.il carotid artery brandies (<-iti;;\t arrow*) Wading into the tumor. Internal carol id artery also js show n

y-lCURl: 3-7

Non-chrum.iMin paraganglioma (chemodecloma, of jugular Nir-amen cj using tinnitus, hearing low ,ind paresis <,il cranial ne » e > l(! to 12 -\. Axial '-mm thiik nn.i^i 1 shows si^n-il-intense i. -is> tltu^c iiHivci hi uiti-roiuedial tmiptM.il 'rone ( IK 2>lHl, 1. 10}. iff,C-i-shows normal cmhlear .u|iieduet. n\ C. Cor nal

im.i^cs show hvpoinlense n i , t-s i .iMiybf \chitr inrow*) i itli ociluded internal jugular vein <N,uk mverrO (IR HtKl, Th -11) IV tit-notes normal opposite internai jugular vein Cu réti iiitt'.r in !! shows fluid in the middle ear caused hv a tu "»or ill'slritv i m g the cms,.uhi.in tube

P e r t i n e n t C o n c e p t s i n H i g h R e s o l u t i o n T e m p o r a l B o n e I m a g i n g 3 3

FICIUKL Cholesterol granuloma ol the medial petrous ,ipe\ (surgically inf irmi ' I). A, /!. Axial 3 mm thick images (IR - 21100, TH = 2(1 [A\ and KO [8]) demonstrate a complex, signal-intense mass (arrow) \sCi(hin the medial petrous apex. Noie considerable hy-pointenv." material within the flmcKonlainmg mass in R. C, Coronair-mm image demonstrates the signal-intense mass < forge arrow) d lorming the left internal auditorv ^anal «umU arww) from below (TR - 800, TH = 20).

P e r t i n e n t C o n c e p t s i n H i g h R é s o l u t i o n T e m p o r a l B o n e I m a g i n g P e r t i n e n t C o n c e p t s i n H i g h R e s o l u t i o n T e m p o r a l B o n e I m a g i n g 3 5

FIGURE .1-10. A longitudinal ultrasound imam' ol' the carotid bifurcation (10 MHz transducer). An irregular, calcific plaque (open arrow) at the origin of the internal carotid artery (ICA) causes moderate narrow­ing of the proxim.il vessel lumen. Normal external carotid artery (ECA). Note the acoustic shadow (arrow) caused by calcium within the plaque.

I IGL'Kl. ^ I I Advanced carotid atherosclerosis with internal carotid artery (ICA) stenosis. A lan;e, circumferential calcific plaque (lumws) causes stenosis o( the »proximal internal carotid artery. Normal external carotid artery (ECA). Note the acou.stic shadow (lur^c ¡\rrow) from heavilv calcified plaque.

SECTION II

Temporal Bone Dissection

CHAPTER 4 Temporal Bone Removal

Knowledge of the human temporal bone is essen­tial for the study of anatomy, histology, and pathol­ogy, and for the practice of microscopic surgical dissection. This knowledge helps provide a solid basis for medical and surgical treatment, and allows rational innovations and progress. It is useful for the surgeon to learn how to remove a temporal bone adequately. The specimen removed should contain the external auditory canal, middle ear, mastoid, inner ear structures, and surrounding petrous pyra­mid.

Technique

T he cal\ ariuni is opened and (ho brain K exposed. I he brain is then removed, care being taken to section cranial nerves Vll and VIII sharplv at the surface of the internal auditorv meatus (I ig. 4 - M ) . Thus the nerve trunks remain with the temporal bom- specimen. 1 he two most common methods of removal arc (1) the block method and (2) the bone plug method

Block Method (Fig. 4 - 1 B )

A motor-driven saw or, preferably, a Strvker saw* (rocker-type oscillating saw) is used. Four saw cuts are made. The first (1) is made at a right angle, as close to the apex of the petrous bone as the regional anatomy will allow. If the cut is made further anterior the eustachian tube can be removed. The second cut (2) is made parallel to the first, through the mastoid

"Available frnm Ihr Orthopedic Fnime Comp.inv, K.il.im.i/uo. MI.

process and as close to the lateral wall as possible. The third cut (3) is made approximately 2.5 cm anterior and parallel to the petrous ridge in the floor of the middle cranial fossa. It includes the bony external ear canal. The fourth cut (4) is made in the horizontal plane, close to the floor of the posterior cranial fossa. This undermining cut severs the bone from its inferior attachments. The temporal bone is still not loose, and great care must be taken to avoid fracturing it.

A "lion-jawed" forceps is used to grasp the spec­imen, and the remaining bony connections are loos­ened by a gentle rocking motion that will free the specimen for further dissection. A sharp chisel, knife, or scissors is used to cut the remaining ligamentous, fibrous, and bony attachments.

Whether the temporal bone is removed by the block method or the bone plug method, the carotid artcrv should be ligated and a suture placed in the external auditorv canal to prevent anv leakage of fluid

Bone Plug Method (Schuknecht's)

This technique requires the use of a specially designed oscillating bone plug saw attached to the conventional Stryker apparatus. The procedure is simple and provides an adequate specimen. For the adult skuli, a 1.5-in diameter saw adjusted to a depth of 1.5 in is used; a 1-in diameter saw adjusted to a depth of 1 in is used for smaller skulls.

The saw should be centered over the arcuate eminence (superior semicircular canal prominence or the superior surface) (Fig. 4-2/1) and directed to the floor of the middle cranial fossa. The skull is held by an assistant, and a stream of water is directed at the

4 0 T e m p o r a l B o n e R e m o v a l T e m p o r a l B o n e R e m o v a l 4 1

42 Temporal Bone Removal Temporal Bone Removal 43

blade for lubrication (Fig. 4 - 2 S ) . Cutting is completed when a loss of resistance is felt, indicating penetra­tion through the base of the skull. An improved cutting action is obtained by slight rotation of the saw. The plug is then grasped with the "lion-jawed" forceps (Fig. 4—2C), and the bone is rotated, permit­ting visualization of the internal carotid artery on its inferior surface. The artery is ligated. Additional attachments are sectioned with a knife, scissors, or osteotome.

Fresh temporal bones can be wrapped in water-sealed cotton or placed in Teflon bags; the air is expelled and the bones are frozen. This helps to preserve the soft tissues for later use.

General Setup and Equipment

A temporal bone dissection station (Fig. 4 - 3 ) should be arranged to simulate actual operating room conditions as closely as possible. Essential items of equipment include a proper table, a comfortable chair, an operating microscope, a motor-driven drill or other otologic drill, suction apparatus, an assort­ment of otologic instruments, and a temporal bone holder. A list of suggested instruments appears be­low.

In general, two types of temporal bone holders

are most commonly used: one that embeds and fixes the temporal bone in a medium such as plaster of Paris, and another that secures the temporal bone specimen with specially designed screw holders, allowing study of all surfaces and relationships of the bone during dissection.

List of instruments and Materials

Operating microscope Drill with a set of

cutting burs Bulb syringe Suction Suction tips No. 1 and

No. 5 Stapes curets Straight canal knife Sickle knife Joint knife Straight pick Stapes bending die Hough hoe

Residents with imaginati these instruments and ma instruments and selecting than those suggested

Whirlybird Small alligator forceps Fenestrometer Scalpel

4-0 silk (mounted on curved needle)

0.05-mm stainless steel

wire Silastic sheeting Gel foam

TORP, PORP, PE tube Scissors (small plastic) Ossicle holder Measuring rod

on can obviate many of terials by adapting broken similar, cheaper materials

CHAPTER 5 Surgical Procedures

T h e g u i d e l i n e s i n t h i s c h a p t e r h a v e b e e n d e s i g n e d

for t h e p r a c t i c a l p u r p o s e o f b e i n g r e a d a n d f o l l o w e d

a s t h e d i s s e c t i o n p r o c e e d s . T h e y a r e i n t e n d e d t o

s e r v e a s a d i a l o g u e b e t w e e n t h e i n s t r u c t o r a n d t h e

s u r g e o n d i s s e c t i n g t h e t e m p o r a l b o n e . A i m s , h i g h ­

l i g h t s , p i t f a l l s , p e r t i n e n t a n a t o m y , a n d s u r g i c a l s t e p s

a r e d i s c u s s e d d u r i n g t h e d i s s e c t i o n i n a n a t t e m p t t o

s i m u l a t e a r a t i o n a l p r o c e d u r e .

T h e a u t h o r s e n c o u r a g e d i s s e c t i o n o f t e m p o r a l

b o n e s a s a n e s s e n t i a l p r e r e q u i s i t e for o t o l o g i c t r a i n i n g

i n r e s i d e n c y p r o g r a m s o r for o t o l a r y n g o l o g i s t s w h o

w i s h t o p r a c t i c e s p e c i f i c t e c h n i q u e s . T h i s p r a c t i c e ,

p l u s a k n o w l e d g e o f a n a t o m y a n d h i s t o p a t h o l o g y , i s

e s s e n t i a l for d e v e l o p i n g r a t i o n a l a n d n o t m e r e l y

i m i t a t i v e m e a n s o f s u r g i c a l t r e a t m e n t .

T h e s u c c e s s i o n o f p r o c e d u r e s h a s b e e n o r g a n i z e d

for t h e fu l l e s t u t i l i z a t i o n o f t h e b o n e s . F o u r " w e t "

t e m p o r a l b o n e s a r e n e e d e d for full c o m p l e t i o n o f

t h e s e g u i d e l i n e s .

W h e n d e s c r i b i n g o r d i s c u s s i n g a t e m p o r a l b o n e

d i s s e c t i o n p r o c e d u r e , " s u p e r i o r " m e a n s t o w a r d t h e

t e m p o r a l l i n e ( c e p h a l a d ) ; " i n f e r i o r " i s t o w a r d t h e

m a s t o i d t i p ( c a u d a d ) , " a n t e r i o r " i s t o w a r d t h e e x t e r ­

n a l a u d i t o r y c a n a l ( v e n t r a l ) ; " p o s t e r i o r " i s a w a v f r o m

t h e e x t e r n a l a u d i t o r y c a n a l ( d o r s a l ) ; " l a t e r a l " i s t o ­

w a r d t h e m a s t o i d c o r t e x ( s u p e r f i c i a l ) ; a n d " m e d i a l "

i s a w a y f r o m t h e m a s t o i d c o r t e x ( d e e p ) .

Simple Mastoidectomy

Aim

E x e n t e r a t i o n ( r e m o v a l ) o f a l l m a s t o i d a i r c e l l s w h i l e

m a i n t a i n i n g t h e i n t e g r i t y o f t h e p o s t e r i o r c a n a l .

Highlights

1 . U s e t h e m i c r o s c o p e a t all t i m e s . r

2 . Dr i l l u n d e r d i r e c t v i s i o n , a v o i d i n g " h o l e s " ( c r i l i

e v e n l y ) .

3 . W h e n i n d o u b t , i d e n t i f y l a n d m a r k s a n d u s • i ,

m a s t o i d c u r e t .

4 . D e v e l o p a g r a d u a l , s t e p - b y - s t e p p r o c e d u r e .

5 . T h i n k a n a t o m i c a l l y a n d t h r e e - d i m e n s i o n a iv .

L o o k for s t r u c t u r e s ; d o n o t " f i n d t h e m . "

6 . K e e p a n a t o m i c a b e r r a t i o n s i n m i n d ( h i g h s .g-

m o i d s i n u s , a n t e r i o r s i g m o i d s i n u s , K o r n e r ' s s e p t u m ,

e t c . ) .

Pitfalls

1 . F a i l i n g t o i d e n t i f y t h e a n t r u m .

A . K o r n e r ' s s e p t u m .

B . I n s u f f i c i e n t t h i n n i n g o f t h e t e g m e n a n d / o r p s -

t e r i o r o s s e o u s c a n a l .

2 . I n j u r i n g a h i g h s i g m o i d s i n u s .

3 . I n j u r i n g t h e fac ia l n e r v e b y g o i n g

A . D e e p t o t h e h o r i z o n t a l s e m i c i r c u l a r c a n a l .

13. T o o far a n t e r i o r i n t h e d i g a s t r i c r i d g e .

4 . D i s l o c a t i n g t h e i n c u s by d r i l l i n g b l i n d l y i n t o t " , e

a n t r u m a r e a .

Surgical Steps

Assess External Aliatomi/ ( F i g . 5 - 1 ) . P l a c e t h e t e m ­

p o r a l b o n e i n s u r g i c a l p o s i t i o n ( s i m u l a t i n g i t s n o r m i l

a n a t o m i c l o c a t i o n for s u r g e r v ) . V i s u a l i z e a n d s t u n '

S u r g i c a l P r o c e d u r e s 4 5

Spine of Henle

Mastoid tip

t h e l a t e r a l s u r f a c e ( c o r t e x ) i n i ts e n t i r e t y f r o m t h e

t e m p o r a l l i n e ( l i n e a t e m p o r a l i s ) s u p e r i o r l y t o t h e

m a s t o i d t ip i n f e r i o r l y . I d e n t i f y t h e p o s t e r i o r a s p e c t

o f t h e o s s e o u s c a n a l a n t e r i o r l y . N o t e t h e p r e s e n c e o f

t h e s u p r a m e a t a l s p i n e ( s p i n e o f H e n l e ) i m m e d i a t e l y

p o s t e r i o r t o t h e o s s e o u s c a n a l . R e v i e w t h e i m a g i n a r y

l i n e s t h a t o v e r l i e t h e m a s t o i d a n t r u m , t h a t i s , b e ­

t w e e n t h e t e m p o r a l l i n e a n d s p i n e o f H e n l e ( f o s s a

m a s t o i d e a o r M a c e w e n ' s t r i a n g l e ) . I m a g i n e t h e i n n e r

s t r u c t u r e s o f t h e m a s t o i d c a v i t y i n a t h r e e - d i m e n ­

s i o n a l f a s h i o n a n d t r a c e y o u r s u r g i c a l p l a n .

Initiate Drilling ( U s e Large Burs, Sauccrize). E m p l o y ­

i n g t h e m i c r o s c o p e , u s e a l a r g e b u r a n d s t a r t s a u c e r -

i z i n g i n a n e v e n f a s h i o n , b e g i n n i n g a t t h e f o s s a

m a s t o i d e a u n t i l a i r c e l l s a p p e a r ( F i g . 5 - 2 A ) . M a k e a

w i d e c o r t i c a l r e m o v a l , i n c l u d i n g t h i n n i n g o f t h e p o s ­

t e r i o r c a n a l . A s y o u g o d e e p e r , k e e p t h i n k i n g o f y o u r

f u t u r e l a n d m a r k s t o o r i e n t y o u r s e l f t o w a r d t h e a n ­

t r u m . Y o u r s u p e r i o r l i m i t i s t h e t e g m e n m a s t o i d e u m

( l e v e l o f t e m p o r a l l i n e ) , s u p e r i o r t o w h i c h l i e s t h e

d u r a o f t h e m i d d l e c r a n i a l f o s s a . T h i n t h e t e g m e n

d o w n , b e i n g c a r e f u l t o k e e p i t i n t a c t ; t h i s i s i m p o r t a n t

i f a d e q u a t e a c c e s s t o t h e a n t r u m i s i n t e n d e d . T h e

p o s t e r i o r c a n a l w a l l s h o u l d b e t h i n n e d d o w n a s w e l l

for t h e s a m e p u r p o s e . A g a i n , d r i l l i n g s h o u l d r e m a i n

e v e n a t a l l t i m e s , n o t s t r a i g h t b u t o r i e n t e d a n t e r i o r l y

t o w a r d t h e n o s e o f o u r i m a g i n a r y p a t i e n t . O u r a n -

t e r o s u p e r i o r l i m i t i s t h e r o o t o f t h e z y g o m a t i c p r o c ­

e s s . T h i s s h o u l d b e o p e n e d w i t h o u t o p e n i n g t h e

e p i t y m p a n u m .

Identify the Lateral Sinus (Sigmoid Sinus). In d r i l l i n g

p o s t e r i o r l y y o u w i l l e n c o u n t e r t h e s i g m o i d s i n u s

( l a t e r a l s i n u s ) ( F i g . 5 - 2 B ) . I t i s i d e n t i f i e d i n s u r g e r y

b y i ts b l u i s h c o l o r a n d s m o o t h b o n y p l a t e . ( In t h i s

4 6 S u r g i c a l P r o c e d u r e s

l-'IGURK 5-2.

S u r g i c a l P r o c e d u r e s 4 7

d i s s e c t i o n w e a r e l o o k i n g for t h e s m o o t h b o n y p l a t e . )

T h e s e c h a r a c t e r i s t i c s a r e t h e b e s t g u i d e s t o t h e s ig­

m o i d s i n u s . A c h a n g e i n t h e s o u n d o f t h e b u r s i s a

h e l p f u l h i n t b u t d o e s n o t suf f ice a s a g u i d e ; v i s u a l i ­

z a t i o n far o u t w e i g h s s e n s a t i o n i n t e m p o r a l b o n e

s u r g e r y . I t m u s t b e r e m e m b e r e d t h a t t h e s i g m o i d

s i n u s d o e s n o t h a v e a u n i f o r m a n a t o m y ; i t c a n b e

h i g h ( l a t e r a l ) o r l o w ( m e d i a l ' d e e p ) . T h e s u r g e o n

s h o u l d b e c a u t i o u s w i t h t h e u s e o f t h e dril l . I n t e r i ­

o r l y , t o w a r d t h e m a s t o i d t ip , t h e a i r ce l l s a r e t o b e

d r i l l e d e v e n l y w i t h t h e leve l o f dr i l l ing s u p e r i o r l y .

L i t t l e by l i tt le , a t y p i c a l k i d n e y - s h a p e d m a s t o i d c a v i t y

b e c o m e s e v i d e n t .

Identify Korncr's Septum mid Antrum. In p r o c e e d i n g

m e d i a l l y ( d e e p e r d o w n ) , o c c a s i o n a l l y o n e m a y e n ­

c o u n t e r a t h i c k p l a t e o f b o n e t h a t m a y g i v e t h e

i m p r e s s i o n o f h a v i n g r e a c h e d t h e a n t r u m . T h i s i s

K ó r n e r ' s s e p t u m , a so l id p l a t e t h a t r e p r e s e n t s t h e

f u s i o n o f t h e s q u a m o u s a n d p e t r o u s p o r t i o n s o f t h e

t e m p o r a l b o n e . W h e n i n d o u b t , g o b a c k t o y o u r

p r e v i o u s l y ident i f i ed l a n d m a r k s a n d s t r u c t u r e s , v e r ­

ify y o u r l o c a t i o n , a n d i m a g i n e t h e b o n e t h r e e - d i m e n -

s i o n a l l y a l o n g w i t h t h e s u s p e c t e d a r e a o f t h e a n t r u m .

U s i n g m a s t o i d c u r e t , c u r e t s u p e r i o r l y a n d p o s t e r i o r l y

unt i l i d e n t i f y i n g t h e " t r u e a n t r u m . " T h e a n t r u m i s

p o s t e r o s u p e r i o r t o t h e o s s e o u s c a n a l . A c o m m o n

e r r o r i s t o g o t o o far b e l o w t h e t e m p o r a l l ine o w i n g

t o l a c k o f t h i n n i n g o f t h e p l a t e . A n i m p o r t a n t g u i d e ­

l ine i s t h a t t h e a n t r u m s h o u l d b e r e a c h e d o r e n t e r e d

f r o m a b o v e i f d a m a g e i s t o b e a v o i d e d . O n c e t h e

a n t r u m i s i d e n t i f i e d , a v o i d u n c o v e r i n g t h e i n c u s ;

i d e n t i l v t h e h o r i z o n t a l s e m i c i r c u l a r c a n a l , w h i c h i s

o n e o f t h e m o s t i m p o r t a n t l a n d m a r k s . A t that p o i n t ,

v i m k n o w t h a t v o u a r c d e f i n i t e l y i n t h e a n t r u m a n d

t h a t v o u a r c s u p e r i o r t o t h e lac ia l n e r v e . K y o u a r e

u n a b l e t o s e c t h e i n c u s , w o r k . i n t e r i o r l y just i n f e r i o r

t o t h e d u r a o l t h e t c g m c i i , t ins i s t h e w i d e s t d i s t a n c e

b e t w e e n t h e o s s i c l e s an i l c p i l v m p a n u n i .

Identify ami f V / m r the Snmluntl Angle, Hard Angle,

and racial , \ V i w ( F i g . 3 - 3 ) . Drill p o s t e r i o r l y , t h i n n i n g

t h e s i g m o i d s i n u s , a n d b e t w e e n t h e s i n u s a n d t h e

t e g m e n p l a t e unt i l t h e y m e e t i n a s h a r p a n g l e ( s i n o -

d u r a l a n g l e o r Ci te l l i ' s a n g l e ) . C o n t i n u e dr i l l ing in­

t e r i o r l y t o w a r d t h e m a s t o i d t ip , e x e n t e r a t i n g ce l l s

f r o m t h e d i g a s t r i c r i d g e a r e a . K e e p i n m i n d t h a t t h e

facial n e r v e a n d its p o i n t o f e x i t f r o m t h e s t y l o m a s t o i d

f o r a m e n a r e i m m e d i a t e l y a n t e r i o r t o t h e d i g a s t r i c

r i d g e . A t th i s p o i n t , w e a r e left w i t h a n i n t a c t a r e a

i n t h e s o - c a l l e d " h a r d a n g l e " ( a n a r e a c o n t a i n i n g t h e

p o s t e r i o r s e m i c i r c u l a r c a n a l i n t h e p l a t e t h a t o v e r l i e s

t h e p o s t e r i o r c r a n i a l f o s s a , a n d a n u n i d e n t i f i e d fac ia l

n e r v e ) . I t i s i m p o r t a n t t o r e m a i n a b o v e t h e a r e a o f

t h e h o r i z o n t a l s e m i c i r c u l a r c a n a l . T h e l o c a t i o n o f t h e

h o r i z o n t a l c a n a l a l l o w s e x p o s u r e o f t h e fossa i n c u d i s

( a n d s h o r t p r o c e s s o f t h e i n c u s ) i n f e r o l a t e r a l l y t o t h e

a n t r u m a n d t h e h o r i z o n t a l c a n a l , t h e e p i t y m p a n u m ,

a n d a l s o t h e e x t e r n a l g e n u o f t h e facial n e r v e , w h i c h

i s m e d i a l t o t h e h o r i z o n t a l s e m i c i r c u l a r c a n a l .

U s i n g a f e n e s t r o m e t e r , m e a s u r e a n i m a g i n a r y t r i ­

a n g l e 1 0 m m f r o m t h e t ip o f t h e s h o r t p r o c e s s o f t h e

i n c u s o r f o s s a i n c u d i s , a l o n g t h e a x i s o f t h e h o r i z o n t a l

s e m i c i r c u l a r c a n a l ( 3 0 d e g r e e s f r o m t h e t e g m e n ) , a n d

1 2 m m f r o m t h e f o s s a i n c u d i s a t a n a n g l e o f 4 5

d e g r e e s f r o m t h e t e g m e n . T h i s a r e a iden t i f i e s a n d

i s o l a t e s t h e h a r d a n g l e ( c o n t a i n i n g t h e p o s t e r i o r s e m i ­

c i r c u l a r c a n a l ) (F ig . 5 - 3 C ) . I m m e d i a t e l y i n f e r i o r t o i t

a n d a n t e r i o r t o t h e s i g m o i d ( l a t e r a l s i n u s ) i s t h e p l a t e

o f b o n e t h a t o v e r l i e s t h e d u r a o f t h e p o s t e r i o r c r a n i a l

f o s s a , w h e r e t h e e n d o l y m p h a t i c s a c i s f o u n d . N o w

i d e n t i f y T r a u t m a n n ' s t r i a n g l e ( F i g . 5 - 3 D ) , b o r d e r e d

b y t h e l a t e r a l s i n u s ( s i g m o i d s i n u s ) , t e g m e n , a n d

s e m i c i r c u l a r c a n a l s . T h i s t r i a n g l e i d e n t i f i e s t h e l o c a ­

t i o n o f t h e p o s t e r i o r c r a n i a l f o s s a .

T h e facial n e r v e i s i d e n t i f i e d b u t n o t u n r o o f e d .

W e will c o m e b a c k t o i t f u r t h e r i n t h e d i s s e c t i o n . T h e

s i m p l e m a s t o i d e c t o m y i s n o w c o m p l e t e d , t h a t is, all

a i r ce l l s h a v e b e e n r e m o v e d ( e x c e p t t h o s e i n t h e

p e t r o u s a p e x ) . R e i d e n t i f y all a n a t o m i c s t r u c t u r e s ,

l a n d m a r k s , t r i a n g l e s , a n d a n g l e s .

Endolymphatic Sac Surgery

Aim

T o i d e n t i l v a n d e x p o s e t h e e n d o l y m p h a t i c s a c

o v e r l v i n g t h e d u r a m a t e r o f t h e p o s t e r i o r c r a n i a l

f o s s a .

Highlights and Surgical Steps

1 . C o m p l e t e s i m p l e m a s t o i d e c t o m y ( a l r e a d y p e r ­

f o r m e d ) .

2 . Dri l ' t o , b u t n o t b e l o w , t h e d o m e o f t h e h o r i ­

z o n t a l s e m i c i r c u l a r c a n a l .

3 . I d e n t i f y , p r e s e r v e , a n d m e a s u r e t h e h a r d a n g l e

c o n t a i n i n g t h e p o s t e r i o r s e m i c i r c u l a r c a n a l .

4 . I d e n t i f y t h e p o s i t i o n o f t h e s i g m o i d s i n u s a n d

its r e l a t i o n s h i p t o T r a u t m a n n ' s t r i a n g l e .

5 . D e c o m p r e s s t h e l a t e r a l s i n u s a n d d i s s e c t t h e

i n f r a l a b y r i n t h i n e cell t r a c t .

6 . I n c i s e t h e e n d o l y m p h a t i c s a c , p r o b e its l u m e n ,

a n d p l a c e S i l a s t i c s h e e t i n g .

4 6 Surgical l'rocedures

H C ; U K L 5 - 1 .

Surgical Procedures 49

Pitfalls

1. Skeletonizing or damaging the posterior semi­

circular canal.

2. Insufficient unroofing of the dural plate.

3. Failing to identify the endolymphatic sac and

its lumen.

4. Damaging the incus.

5. Depositing debris in the middle ear.

6. Lateral sinus bleeding.

Procedure

In endolymphatic sac surgery, the authors advo­cate a thorough simple mastoidectomy (which has already been done). In our dissection, we have al­ready identified the bone plate overlying the poste­rior cranial fossa dura. Redefine Trautmann's trian­gle, identify the hard bone containing the posterior semicircular canal, and measure the distances again (Fig. 5-4B): 10 mm from the tip of the short process of the incus or fossa incudis, along the axis of the horizontal semicircular canal (30 degrees from the tegmen); 12 mm from the fossa incudis at an angle of 45 degrees from the tegmen. Drill into the infra-labyrinthine cell tract to help expose the sac location. Pav special attention to the position of the sigmoid sinus. On occasion it partially overlies the dural plate, reducing the size of Trautmann's triangle. The plate is thinned down to eggshell thickness, then gently elevated and separated from the underlying dura with a duckbill elevator. The sac is identifiable as a thickened white area of the dura over the thin sur­rounding dura (Fig. 5 -5 ) . The posterior semicircular canal shoud not be thinned or skeletonized. Drilling is done immediately inferior to this area. The sac comes toward the dura from the direction of the posterior semicircular canal. If the lateral sinus is in such a position that it tends to partially cover the dura or make access to it difficult, first recheck the position of the bone; the "head" might be bent too far forward. If the sinus is still prominent after repositioning of the "head," it should be decom­pressed by removing part of its bony covering facing the dura. Infralabyrinthine cells might have to be drilled (leading toward the jugular bulb). The sac is incised gently with a sickle knife and the lumen probed with a Whirlybird.

Facial Recess Approach, Posterior Tympanotomy

Aim

Removal of air cells immediately lateral to the facial nerve at the external genu (facial recess collec­tion of air cells).

Highlights

1. Define the landmarks clearly.

2. Thin the posterior canal wall.

3. Drill parallel to facial nerve fibers.

4. If fhe approach is troublesome, combine trans-

mastoid and transcanal visualization.

PitfaVs

1. Damaging the facial nerve.

2. Perforating the bony external ear canal.

3. Perforating the tympanic membrane. 4. Those of a simple mastoidectomy.

Procedure

Define your landmarks (Fig. 5-6/4) . The external genu of the facial nerve is medial; the fossa incudis is superior. Thin the posterior canal wall. Identify the facial nerve by its pearly white color underneath the thin layer of bone. The bone is still too thick; thin it down very carefully by drilling parallel to the direction of the facial nerve fibers (Fig. 5 - 6 8 ) . Small cutting burs should be used since the recess is quite small. Inferiorly, identify the chorda tympani (which is to be preserved) as it leaves the facial nerve in an anterosuperior direction; it then takes a lateral direc­tion toward the annulus (Fig. 5-7A). On occasion, the facial recess is quite small and the procedure difficult. Rather than insisting on taking unnecessary risks, use a combined transcanal-transmastoid ap­proach.

Text continued on nage 54

5U Surgical Procedures

Horizontal canal

H G U K I . n 4

Surgical Procedures 51

i I G U R I :

S u r g i c a l P r o c e d u r e s

FIGURI; 5 li

S u r g i c a l P r o c e d u r e s 5 3

Horizontal facial nerve

FIGURE 5-:

5 4 S u r g i c a l P r o c e d u r e s

O n c e t h e r e c e s s i s o p e n e d , t h e l a n d m a r k s a r e

r e i d e n t i f i e d : t h e e x t e r n a l g e n u o f t h e f ac i a l n e r v e i s

m e d i a l ; t h e f o s s a i n c u d i s i s s u p e r i o r ; t h e c h o r d a

t y m p a n i i s i n f e r o l a t e r a l a n d p o s t e r i o r ; a n d t h e t y m ­

p a n i c m e m b r a n e i s a n t e r o l a t e r a l .

N o w o b s e r v e t h e f o l l o w i n g s t r u c t u r e s ( F i g . 5 - 7 B ) ;

t h e h o r i z o n t a l p o r t i o n o f t h e f ac i a l n e r v e , t h e l e n t i c ­

u l a r p r o c e s s o f t h e i n c u s , t h e i n c u d o s t a p e d i a l j o i n t ,

t h e c a p i t u l u m o f t h e s t a p e s , a n d t h e s t a p e d i a l t e n ­

d o n . N e x t i d e n t i f y t h e p r o m o n t o r y , a n d i n f e r o m e -

d i a l l y t h e r o u n d w i n d o w n i c h e .

Cochlear Implant (Facial Recess Approach)

Aim

T o p l a c e a n e l e c t r o d e i n t o t h e c o c h l e a b y s l i d i n g i t

t h r o u g h t h e r o u n d w i n d o w . ( W e wi l l d e a l o n l y w i t h

i n t r a c o c h l e a r e l e c t r o d e p l a c e m e n t a n d w i t h e l e c ­

t r o d e s t h a t a r e p l a c e d far i n t o t h e i n t e r i o r o f t h e

c o c h l e a . )

Highlights

1 . F . n s u r e g o o d v i s u a l i z a t i o n e i a a n a d e q u a t e l . u i a l

r e c e s s a p p r o a c h .

2 . C l e a r l v i d e n t i l v t h e r o u n d w i n d o w n i c h e a n d

r o u n d w i n d o w m e m b r a n e .

Pitfalls

1 . [ h o s e o f t h e fac ia l r e c e s s a p p r o a c h i t s e l f .

2 . I n a d e q u a t e v i s u a l i z a t i o n o f t h e r o u n d w i n d o w ,

w i t h t h e e l e c t r o d e u n a b l e t o b e p a s s e d b e y o n d t h e

h o o k .

Surgical Steps

1 . T h o s e o f a s i m p l e m a s t o i d e c t o m y a n d facia l

r e c e s s a p p r o a c h .

2 . P r e p a r e a s e a t for t h e i n t e r n a l r e c e i v e r .

3 . I n s e r t t h e i n t r a c o c h l e a r e l e c t r o d e .

Procedure

A t t h i s p o i n t i n t h e d i s s e c t i o n , t h e m a i n d r i l l i n g

for t h e p r o c e d u r e h a s b e e n d o n e . Y o u a r e l=ft w i t h

i n s e r t i n g t h e e l e c t r o d e t h r o u g h t h e r o u n d v i n d o w

a n d d r i l l i n g a s e a t f o r t h e i n t e r n a l r e c e i v e r p o s t e r o ­

s u p e r i o r t o t h e m a s t o i d c a v i t y . L o c a t e a p o s ; i o n for

t h e i n t e r n a l r e c e i v e r ; i t s h o u l d b e i m m e d i a t e l y p o s ­

t e r i o r t o t h e p o s t e r i o r l i m i t o f t h e d r i l l e d M a s t o i d

c a v i t y , w i t h i t s a n t e r i o r ( t o w a r d t h e e a r c a n a l ) b o r d e r

n o f u r t h e r t h a n w h e r e t h e b o r d e r o f t h e i m : g i n a r y

p i n n a ( a u r i c l e ) w o u l d b e i f i t w e r e p u s h e d p c s t e r i o r

( t h a t i s , i m m e d i a t e l y p o s t e r i o r t o t h e p o s t e r i o r o o r d e r

o f t h e p i n n a ) . S u p e r i o r l y , t h e b o r d e r s h o u l d n o t b e

a b o v e t h e s u p e r i o r b o r d e r o f t h e p i n n a . D r i l l a s e n t ,

u s i n g a s a g u i d e l i n e t h e c i r c u m f e r e n c e o f t h e i n t e r n a l

r e c e i v e r o f y o u r p r a c t i c e e l e c t r o d e ( F i g . 5 - 8 ) . I f a

p r a c t i c e e l e c t r o d e i s n o t a v a i l a b l e , d r i l l a s e a t i n t o

w h i c h a n i c k e l - s i z e d c o i n w o u l d fit. D r i l l i n g c a n b e

d o n e c a r e f u l l y w i t h a r e g u l a r b u r , o r i t c a n b e d o n e

w i t h e i t h e r a b u t t e r f l y b u r o r a b u r s p e c i a l l y d e s g n e d

b y o n e o f t h e c o c h l e a r i m p l a n t m a n u f a c t u r e r s [ f a

s c r e w t y p e o f i n t e r n a l r e c e i v e r i s t o b e u s e d , dr i l l

f o u r h o l e s i n t h e c o r r e s p o n d i n g o p e n i n g s o f the b a s e

o f t h e p e d e s t a l t o a m a x i m u m d e p t h o f 2 m m .

R e g a r d l e s s o f t h e t y p e o f i n t e r n a l r e c e i v e r , w i t h a

s m a l l b u r d r i l l t w o s m a l l h o l e s i m m e d i a t e l y s u p e r i o r

a n d i n f e r i o r t o t h e l o c a t i o n o l y o u r a l r e a d v d i l l e d

s c a t , t h a t i s , t w o h o l e s s u p e r i o r l v a n d t w o h o l e s

i n f e r i o r l y ( F i g . 5 - 9 / 1 ) . B r i n g t h e s m a l l h o l e s t o g e t h e r

v c r v c a r e f u l l y , t h e n p a s s 2 -0 s i lk t h r o u g h t h e s -

o p e n i n g s ( I ig. 5 l ' / i ) ; t h i s u ill he u s e d to crus*. o v e r

t h e i n t e r n a ! r e c e i \ o i a m i s e a t i t i n p l a c e . D o m i l p l a t e

\ o u r i n t e r n a l r e c e i v e r v o l .

O u r a t t e n t i o n i s n o w t u r n e d h a c k t o t h e a . l i v e

e l e c t r o d e A g a i n , \ i s u , i h / c t h e r o u n d w i n d o w I-P h e .

II v i s u a l i z a t i o n is no t , u l e . | u , i to a t r . m s c a n a I a p p - - >a. h

t a n h e n u d e \ c i i l v t h e o p e n i n g o t t h e r o u n d w i n ­

d o w i m h e O n o c c a s i o n , i t i s n c c e s s . i r v o r u s e . ; I t o

g e n t l v dr i l l t h e . i n t e r i o r b o r d e r o l t h e n i c h e ( I i ; . 5 -

y ( ' ) . I h i s w i l l p r o v i d e a s l i g h t l y l a r g e r o p e n i n g " . t h

b e t e r v i s u a l i z a t i o n , a n d a t t h e s a m e t i m e wi l l p r . i c n t

a " s t r a i g h t s h o t " a t t h e c o c h l e a , s k i p p i n g t h e ' o o k

p o r t i o n t h a t s o m e t i m e s i s d i f f i c u l t t o b y p a s s . P o s ( ion

t h e e l e c t r o d e i n t h e o p e n i n g o f t h e w i n d o w a n d h e n

g e n t l y p u s h i t i n , u s i n g a b l u n t p i c k o r w i r e g u i c e o r

o n e o f t h e s p e c i a l e l e c t r o d e g u i d e s p r o v i d e d b y t h e

i m p l a n t m a n u f a c t u r e r s ( F i g . 5 - 1 0 ) . I f t h e r e i s s u n e

r e s i s t a n c e , i t i s l i k e l v t h a t t h e e l e c t r o d e i s c a u g h u p

i n t h e h o o k . R e t r a c t t h e e l e c t r o d e g e n t l y a n d t r t o

r o t a t e it , w h i l e i m a g i n i n g t h e d i r e c t i o n o f t h e c o c h - e a .

O n t h e lef t , fo r e x a m p l e , t u r n g e n t l y t o w a r d t h e r ' ? h t

( c l o c k w i s e ) ; o n t h e r i g h t , t u r n g e n t l y t o w a r d t h e ' e f t

7V.v( tvntiiiiicd on paee 59

S u r g i c a l P r o c e d u r e s 5 5

FIGURE 5-8

Surgical I'rocedures

15mm

Facial nerve

Surgical Procedures 57

~Iectrode

In scala tympani

B

Scala tympani

A

'. <'-' /'SIrf,'/'h.e'\~11,1

Round window niche ' .

A

('":'

"

B

o

56

FIGURE 0- J(J

HCLÌRK 5 - 1 1

Surgical Procedures 59

(counterclockwise). Place the electrode and then se­cure the internal receiver with either screws or su­tures (Fig. 5 -11 ) .

Transmastoid Facial Nerve Decompression

Highlights and pitfalls are discussed in the text.

Surgical Steps

1. Those of a simple mastoidectomy. 2. Identify the different segments of the facial

nerve, and skeletonize the fallopian canal.

3. Fracture and remove any bony covering.

4. Open the sheath of the facial canal.

Procedure

In the course of the complete simple mastoidec­tomy, the vertical portion and external genu of the facial nerve were fairly well delineated. For practical surgical purposes the facial nerve can be divided into three segments: (1) that within the internal auditory canal; (2) the tympanic segment (horizontal/middle ear); and (3) the vertical segment (mastoid). We will deal now with the vertical and horizontal segments, in that order.

From the external genu, the nerve proceeds ver­tically to the stylomastoid foramen at the level of the anterior edge of the digastric ridge (Fig. 5 -12) . It is important to visualize its anatomy and, if possible, compare it with cither bones, since there is consid­erable variation. The nerve is lateral to the horizontal canal; however, it may have a posterior projection at the genu, lending itself to potential damage. It is useful to visualize the nerve anterior to the digastric ridge and to appreciate how lateral it becomes as it reaches the mastoid tip. Its tympanic or middle ear segment appears in the region of the cochleariform process at the geniculate ganglion, then runs poste­riorly towards the oval window (stapes) to a point just inferior and usually medial (deep) to the hori­zontal semicircular canal.

The vertical segment can be dissected from the

level of the fossa incudis or from the digastric ridge.

From the ridge it can be followed superiorly to the

external genu; however, this is not a reliable land­

mark. Although this approach is perfectly acceptable,

the authors tend to follow nerves peripherally rather

than centrally, which seems both safer and simpler.

After visualization of the genu, the canal is skele­

tonized all the way down to the stylomastoid fora­

men. Drilling is done in strokes parallel to the direc­

tion of the nerve (superior to inferior or vice versa).

Exposure of the tympanic segment is helped by

enlarging the aditus ad antrum. This dissection, plus

enlargement of the facial recess approach, allows

visualization anteriorly toward the cochleariform

process. Visualize the segment at the level of the

oval window and the pyramidal eminence. This is a

very useful image to keep in mind. If necessary,

adequate 'isualization can be obtained by a combined

approach. Visualize the tympanic segment through

the canal. It is also possible to obtain adequate

visualization by removing the incus (Fig. 5 -13A) .

Before disarticulating the incus, try to drill under it

without damaging or dislocating it, using the smallest

possible burs. Now try to remove and replace the

incus. If drilling toward the geniculate ganglion was

incomplete, drill now without the incus in place.

(The incus should be left in place for use in the next

procedure; however, practice placing and replacing

the incus to become familiar with its normal anatomic

position.) Once the entire facial canal has been

thinned to eggshell consistency, fracture it with a

pick and lift the bone fragments gently with a Whirly-

bird without using the facial nerve as a fulcrum (Fig. 5 -

138) . The sheath is then opened with a sharp sickle

knife (Fig. 5-13C) .

Canalplasty (Fig. 5 -14)

Aim I

Enlargement of the bony canal and visualization

of the enhre fibrous and bony annulus.

Pitfalls

Excessive drilling of the anterior wall and entrance

into the temporomandibular joint space.

6 0 S u r g i c a l P r o c e d u r e s

['IGL'Ri: 5- 12

62 Surgical Procedures

Ant. canal wall

Tympanic membrane

A Post, canal wall

I Anterosuperior quadrant

B

FIGURI: s-14

Procedure

Surgical Procedures 63

Using a large bur, drill the canal wall evenly until visualization of the entire fibrous annulus is achieved (Fig. 5-14A) . Do not drill in one spot, but "sweep" the bur gently with even pressure and go one step at a time. (Skin procedures will not be dealt with, since the skin is thick, tight, and difficult to elevate adequately for these purposes in harvested temporal bones.)

Underlay Graft of the Tympanic Membrane

Aim

Placement of a graft under the tympanic mem­brane, covering all edges of the perforation.

Procedure

V i s u a l i z e t h e t v m p a n i c m e m b r a n e . I m a g i n e i t i n

f o u r q u a d r a n t s ( F i g . 5 - 1 4 R ) . U s i n g a s t r a i g h t p ick

a n d a s i ck le kni fe , m a k e a c e n t r a l p e r f o r a t i o n ( F i g .

3 - 1 5 / 1 ) . Fill t h e m i d d l e e a r s p a c e w i t h Cie l foam ( F i g .

5 - 1 5 / t ) . O b t a i n a p i e c e o f fasc ia ( o r p a p e r ) t h a t

e x c e e d s t h e s i z e o l t h e p e r l o r a t i o n b v a t l eas t 1 0 ' . ; .

S c a r i f v t h e u n d c r s u r f a c c o f t h e t v m p a n i c m e m b r a n e

a r o u n d t h e p e r l o r a t i o n , u s i n g a H o u g h h o e . N o w

p l a c e t h e graft o v e r t h e p e r f o r a t i o n a n d p o s i t i o n i t

m e d i a l l y b v u s i n g t h e H o u g h h o e ( F i g . 5 - 1 5 C D).

Ossiculoplasty (Incus Procedures)

Aim

Restoration of ossicular chain continuity (in this case, where incus problems are the cause of the loss).

Remove the "graft," the entire tympanic mem­brane, and the Gelfoam filling the cavity. Now vis­ualize the cavity and what is found beneath the different quadrants (see Fig. 5 -14B) . Familiarize yourself with the anatomy. Mobilize the temporal bone and learn what areas can be seen best at different angles. Palpate the ossicles with a blunt pick, and observe the round window niche area, the opening of the eustachian tube, the stapedial tendon, and other features. Compare the views of the middle ear cavity with the transcanal and posterior tympan­otomy approaches. The incus is already loose.

Clip the distalmost portion of the long process of the incus ("necrosis of the lenticular process") (Fig. 5-16A) . Since the mastoidectomy has been done already, remove a piece of "cortical bone" posterior to the mastoid cavity opening. Using a small bur, delineate a square of bone and remove it. Shape this piece of bone in order to restore continuity. Drill a small acetabulum for the head of the stapes and a groove for the remaining long process of the incus (Fig 5 - 1 6 B - E ) .

Remove the entire incus. Restoration of ossicular continuity in this case can be achieved in a number of ways (Fig. 5 -17 ) . We will use a sculptured incus, a sculptured cortical bone and, if available, a partial ossicular replacement prosthesis (PORP). Clip the short process of the incus and drill an acetabulum in the remaining long process, for fitting over the head of the stapes. Then drill a groove over the remaining body for fitting under the malleus. Now try to sculpture a piece of cortical bone in this same shape. Avoid contact of the incus graft with the promontory. Try a PORP as well, if available.

Intact Bridge Mastoidectomy (IBM), Modified Radical Mastoidectomy, and Radical Mastoidectomy

Aims

Exteriorization of the disease process within the epitympanum, antrum, and mastoid to the meatus.

Procedure

6 4 S u r g i c a l P r o c e d u r e s S u r g i c a l P r o c e d u r e s 6 5

IMC.URI-: 5 1?.

Surgical Procedures 67

The IBM is a version of modified radical mastoidec­tomy with bridge preservation, allowing tympano­plasty repairs.

Highlights

1. Enlarging the anterior canal wall without open­ing the temporomandibular joint, and visualizing the entire fibrous and bony annulus.

2. Large meatoplasty is crucial for the success of the procedure.

Pitfalls

1. Incomplete removal of the posterior meatal

wall.. 2. Poor meatoplasty.

Surgical Steps

1. Meatoplasty. 2. Canalplasty. 3. Saucerize the mastoid circumferentially. 4. Enlarge the aditus and sculpture the bridge to

widen the mesotympanum. 5. Remove all disease. 6. Preserve when possible the anterior tympanic

membrane and manubrium. 7. Use a ventilation tube. 8. Ossiculoplasty, tympanoplasty. 9. Obliterate the aditus with periosteum or car­

tilage. 10. Obliterate the mastoid (usually not necessary). 11. Thiersch graft (at the primary procedure or 3-

4 weeks postoperatively).

Procedure

These procedures involve removal of the posterior meatal wall. The original Bondy modified radical mastoidectomy implies this step; however, in the Bondy procedure the middle ear cavity is not entered. Both the IBM and the modified radical mastoidec­tomy imply entering the middle ear.

Intact Bridge Masto idectomy

The "bridge" is the most medial portion of the posterosuperior meatal wall; it is literally the bridge that crosses the attic toward the tegmental area. It has both anterior and posterior buttresses. The an­terior buttress is the superior portion where the posterior bony canal meets the tegmen. The posterior buttress is the inferior portion where the posterior bony canal meets the floor of the external auditory canal, lateral to the facial nerve. Drill the anterior canal wall, enlarging it until clearly visualizing the entire fibrous and bony annulus but without entering the temporomandibular joint space (Fig. 5-18/1). Lower the posterior canal wall, leaving the bridge intact (Fig. 5 -18B) . Normally the facial recess is not drilled open, but in our bone this has already been done. Visualize and section the tensor tympanic tendon (this maneuver lateralizes the manubrium) (Fig. 5 -18C) . At this point in a clinical case, you would place a tube in the tympanic membrane rem­nant and perform an ossiculoplasty, place a graft, and obliterate the aditus with either periosteum or cartilage.

Modified Radical Masto idectomy

For practical purposes, a modified radical mastoid­ectomy has already been performed, except that the bridge is still intact. Removing the bridge will com­plete the modified radical mastoidectomy.

There a r e two approaches for the modified radical mastoidectomy: the "inside-out" or atticotomy ap­proach, a n t the "outside-in" or atticoantrotomy ap­proach. We have already performed, step by step, an outside-in approach in this bone. In our next bone, which will be used for middle ear dissection, the inside-out modified radical mastoidectomy ap­proach will be used.

Drilling is started in the epitympanum and fol­lowed posteriorly into the antrum. In doing this, the bridge is removed. The antrum is identified, as well as the dome of the horizontal canal (Fig. 5-19A) . With this landmark under direct vision, mastoidec­tomy is performed and the posterior bony wall is lowered to the level of the facial ridge (Fig. 5 -19B) . This method is easier and safer than the outside-in approach in a sclerotic mastoid.

Radical Masto idectomy (Fig. 5 -20)

The purpose of this procedure is to create an exteriorized cavity that includes the mastoid, antrum,

6 8 S u r g i c a l P r o c e d u r e s S u r g i c a l P r o c e d u r e s

FIGURE 5-19.

S u r g i c a l P r o c e d u r e s 71

e p i t y m p a n u m , a n d m e s o t y m p a n u m , l e a v i n g a d r y

e p i t h e l i a l i z e d c a v i t y c o n t i n u o u s w i t h t h e e x t e r n a l

m e a t u s . T h e p r o c e d u r e i n v o l v e s r e m o v i n g t h e m a l ­

l e u s a n d i n c u s w h i l e l e a v i n g t h e s t a p e s i n t a c t . T h e

m u c o s a o f t h e m i d d l e e a r i s r e m o v e d a s w e l l .

Petrous Drainage

Aim

E x e n t e r a t i o n ( r e m o v a l ) o f p e t r o u s a p e x a i r ce l l s

w h i l e m a i n t a i n i n g t h e i n t e g r i t y o f t h e i n n e r e a r

s t r u c t u r e s .

T h e p e t r o u s a p e x ( p e t r o u s p y r a m i d ) h a s t w o m a j o r

g r o u p s o f a ir ce l l s , t h e a n t e r i o r a n d t h e p o s t e r i o r .

T h e p o s t e r i o r g r o u p ( F i g . 5 - 2 1 4 ) i n c l u d e s cell t r a c t s

s u p e r i o r , p o s t e r i o r , a n d i n f e r i o r t o t h e s e m i c i r c u l a r

c a n a l s ; t h e a n t e r i o r g r o u p (Fig . 5 - 2 1 6 ) i n c l u d e s cel l

t r a c t s i n t h e s u p e r o m e d i a l a s p e c t o f t h e e u s t a c h i a n

t u b e ' o r i f i c e , w h e r e t h e c a r o t i d a r t e r y i s l o c a t e d . I n

o r d e r t o r e a c h t h e s e a n t e r i o r cel l t r a c t s , a r a d i c a l

m a s t o i d e c t o m y ( d e s c r i b e d a b o v e ) m u s t b e d o n e . H y -

p o t y m p a n i c a i r ce l l s a l s o a r e p r e s e n t a d j a c e n t t o t h e

r o u n d w i n d o w n i c h e .

Posterior Cell Tract

F o r th i s d i s s e c t i o n , s k e l e t o n i z a t i o n o f t h e s i g m o i d

s i n u s , t h e p o s t e r i o r f o s s a d u r a , a n d t h e facial n e r v e

i s r e q u i r e d . This h a s a l r e a d y b e e n d o n e . O u r n e x t

s t e p i s t o e a r c f u l l v s k e l e t o n i z e t h e s e m i c i r c u l a r c a n a l s

(F ig . 5 - 2 I C ) . U s e s m a l l b u r s (."1-0 o r 4 - 0 s i z e ) . F o u r

a r e a s o r t r a c t s , w h i c h m a v o r m a v n o t b e p r e s e n t ,

s h o u l d b e l o o k e d l o r . T h e first t r a c t i s t h r o u g h t h e

a r c h o l t h e s u p e r i o r s e m i c i r c u l a r c a n a l I h e s e c o n d

t rac t i s a n t e r o s u p e r i o r to t h e s e m i c i r e u l a r c . tnal , l e a d ­

i n g i n t o t h e s t i p r a c o c h l e a r a ir c e l l s \ isvialize th i s t r a c t

a n d its r e l a t i o n s h i p t o t h e facial n e r v e . T h e t h i r d t r a c t

i s p o s t e r i o r t o t h e s u p e r i o r c a n a l a n d r u n s b e t w e e n

t h e t e g m e n m a s t o i d e u m a n d c o m m o n c r u s o f t h e

m e m b r a n o u s l a b y r i n t h t o w a r d t h e i n t e r n a l a u d i t o r y

c a n a l . D o n o t e x p o s e t h e c o m m o n c r u s — t h i s i s t o b e

d o n e l a t e r . T h e i n t e n t i o n h e r e i s t o o b t a i n a b e t t e r

v i s u a l i z a t i o n o f t h i s a n a t o m i c r e l a t i o n s h i p . T h e f o u r t h

o r r e t r o l a b y r i n t h i n e cel l t r a c t i s i n f e r i o r t o t h e p o s t e ­

r i o r s e m i c i r c u l a r c a n a l , m e d i a l t o t h e v e r t i c a l s e g m e n t

o f t h e facial n e r v e , a n d s u p e r i o r t o t h e j u g u l a r b u l b .

Anterior Cell Tract

A r a d i c a l m a s t o i d e c t o m y h a s a l r e a d y b e e n d o n e .

T h e t e g m e n s h o u l d b e s k e l e t o n i z e d a n d t h e a n t e r i o r

w a l l t h i n n e d ; b o t h o f t h e s e p r o c e d u r e s h a v e a l r e a d y

b e e n p e r f o r m e d . T h e ce l l s o f t h e a n t e r i o r t r a c t a r e

f o u n d i n t h e " p e r i t u b a l " a n d c a r o t i d a r e a s i n t h e

b o n y w a l l ju s t m e d i a l t o t h e e u s t a c h i a n t u b e or i f i ce

a n t e r i o r t o t h e p r o m o n t o r y . T h e s e ce l l s a r e c l o s e l y

a s s o c i a t e d w i t h t h e t e g m e n m a s t o i d e u m ; t h e r e f o r e ,

d i s s e c t i o n m u s t b e d o n e v e r y c a r e f u l l y . T h e a u t h o r s

p r e f e r t o u s e s m a l l c u r e t s a t th i s leve l .

Labyrinthectomy (Transmastoid Labyrinthine Dissection)

Aim

C o m p l e t e r e m o v a l o f t h e s e m i c i r c u l a r c a n a l s a n d

soft t i s s u e o f t h e v e s t i b u l e

Highlights

X . T h e s i n o d u r a l a n g l e m u s t b e c o m p l e t e l y

t h i n n e d for a d e q u a t e e x p o s u r e o f t h e v e s t i b u l e .

2 . T h e t e g m e n m u s t b e t h i n n e d for a d e q u a t e v i s ­

u a l i z a t i o n o f t h e s u p e r i o r a s p e c t o f t h e s e m i c i r c u l a r

c a n a l s .

Procedure

T h e t h r e e s e m i c i r c u l a r c a n a l s a r e s k e l e t o n i z e d unt i l

t h e m e m b r a n o u s l a b v r i n t h i s v is ible t h r o u g h t h e b o n e

a s a t h i n b l u e l ine ( F i g . 5 - 2 2 , 4 ) . N o t e t h e r e l a t i o n s h i p

o f t h e facial n e r v e t o t h e h o r i z o n t a l s e m i c i r c u l a r c a n a l

(F ig . 5 - 2 2 / i ) . F e n e s t r a t e t h e h o r i z o n t a l c a n a l . U n r o o f

t h e p o s t e r i o r a n d a n t e r i o r p o r t i o n s o f t h e s u p e r i o r

s e m i c i r c u l a r c a n a l . F o l l o w t h e s u p e r i o r s e m i c i r c u l a r

c a n a l unt i l . t r e a c h e s its c o m m o n c r u s w i t h t h e

p o s t e r i o r s e m i c i r c u l a r c a n a l . T h e a r c u a t e a r t e r y p e n ­

e t r a t e s t h e h a r d l a b y r i n t h i n t h e c e n t e r o f t h e a r c h o f

t h e s u p e r i o r s e m i c i r c u l a r c a n a l . G o b a c k t o t h e s u ­

p e r i o r s e m i c i r c u l a r c a n a l , i d e n t i f y t h e s u p e r i o r v e s ­

t i b u l a r n e r v e , a n d fo l low i t i n t o t h e i n t e r n a l a u d i t o r y

m e a t u s ( F i g . 5 - 2 2 C ) . V i s u a l i z e t h e c o m m o n c r u s .

N o w i d e n t i f y t h e e n d o l y m p h a t i c d u c t a s i t e n t e r s t h e

p o s t e r o s u p e r i o r e n d o f t h e v e s t i b u l e . Ver i fy its p r e s ­

e n c e a n d its d i r e c t i o n t o w a r d t h e e n d o l y m p h a t i c s a c ;

t h i s i s a u s e f u l a n a t o m i c r e l a t i o n s h i p to k e e p in m i n d ,

s i n c e th i s a r e a i s n o t v i s u a l i z e d i n e n d o l y m p h a t i c s a c

e n h a n c e m e n t p r o c e d u r e s . B o n e i s n o w r e m o v e d f r o m

72 S u r g i c a l P r o c e d u r e s

FIGURE 5 21 FIGURE 5-22.

7 4 S u r g i c a l P r o c e d u r e s

t h e f l oo r o f t h e v e s t i b u l e w h e r e t h e i n f e r i o r v e s t i b u l a r

n e r v e i s e n c o u n t e r e d .

F o l l o w t h e c o m m o n c r u s a n t e r i o r l y i n t o t h e v e s t i ­

b u l e . O p e n i t w i d e l y a n d t r y t o i d e n t i f y t h e m e m ­

b r a n e o f t h e u t r i c l e a n d s a c c u l e . N o t i c e t h e r e l a t i o n ­

s h i p s a n d d i s t a n c e s b e t w e e n t h e f o o t p l a t e , s a c c u l e

a n d u t r i c l e . N o w s k e l e t o n i z e t h e r o u n d w i n d o w '

s i n c e t w o a d d i t i o n a l o b s e r v a t i o n s c a n b e m a l e i n

t h i s a r e a . F i r s t , dr i l l c a r e f u l l y a t t h e i n f e r i o r n . , r g i n

o f t h e r o u n d w i n d o w a n d i d e n t i f y t h e s i n g u l a r n e r v e

( F i g . 5 - 2 3 / 1 ) . S e c o n d , dr i l l t h i s a r e a a n d i d e n t i f y t h e

h o o k o f t h e b a s a l t u r n o f t h e c o c h l e a ( F i g 5 - / 3 B )

C o c h l e a r e l e c t r o d e s m a y b e o b s t r u c t e d i n t h i s a r e a

w h e n b e i n g i n s e r t e d i n t o t h e c o c h l e a . V i s u a l i z e i t s

Singular nerve

R o u n d w i n d o w

C o c h l e a ( b a s a l turn)

S u r g i c a l P r o c e d u r e s 7 5

a n a t o m y i n o r d e r t o s e e t h e d i r e c t i o n i n w h i c h t h e

e l e c t r o d e s h o u l d b e p o i n t e d a n d t h e a m o u n t o f b o n e

t h a t s h o u l d b e d r i l l e d t o b y p a s s t h e h o o k .

Middle Ear Dissection

Procedure

T h i s p r o c e d u r e i s s t a r t e d w i t h a n e w w e t b o n e .

S k i n p r o c e d u r e s w i l l n o t b e d e a l t w i t h s i n c e t h e s k i n

i s t h i c k , t i g h t , a n d d i f f i c u l t t o e l e v a t e a d e q u a t e l y for

t h e s e p u r p o s e s . I d e n t i f y t h e w a l l s o f t h e e a r c a n a l .

V i s u a l i z e t h e t y m p a n i c m e m b r a n e ; i m a g i n e i t i n f o u r

q u a d r a n t s ( F i g . 5 - 2 4 / \ ) . M a k e o p e n i n g s i n t h e a n t e r o -

s u p e r i o r , a n t e r o i n f e r i o r , p o s t e r o i n f e r i o r , a n d p o s t e r ­

o s u p e r i o r q u a d r a n t s . N o w g e n t l y e l e v a t e t h e t y m ­

p a n i c m e m b r a n e a n d i d e n t i f y t h e a r e a s a n d

s t r u c t u r e s b e n e a t h t h e f o u r o p e n i n g s . V i s u a l i z e w h a t

i s f o u n d b e n e a t h t h e p o s t e r o s u p e r i o r q u a d r a n t o p e n ­

i n g . N o w b e n d t h e t v m p a n i c m e m b r a n e f o r w a r d ; i f

i t i s t o o b r i t t l e , r e m o v e i t . V i s u a l i z e t h e m i d d l e e a r

( F i g . 5 - 2 4 B ) . P a l p a t e t h e o s s i c l e s , J a c o b s o n ' s n e r v e ,

t h e r o u n d w i n d o w n i c h e a r e a , a n d t h e o p e n i n g o f

t h e e u s t a c h i a n t u b e , a n d i d e n t i f y t h e t e n s o r t y m p a n i .

R e m o v e t h e s k i n , l e a v i n g t h e a n n u l u s i n t a c t . I d e n ­

tify t h e t y m p a n o s q u a m o u s s u t u r e s u p e r i o r l y a n d t h e

t y m p a n o m a s t o i d s u t u r e p o s t e r i o r l y . B e t w e e n t h e s u ­

t u r e s i s t h e v a s c u l a r s t r i p . I d e n t i f y t h e a n t e r i o r w a l l

a n d c a r e f u l l v d r i l l t h e a n t e r i o r b o n v o v e r h a n g w i t h ­

o u t e n t e r i n g t h e t e m p o r o m a n d i b u l a r j o i n t s p a c e .

E n l a r g e t h e c a n a l u n t i l t h e e n t i r e t v m p a n i c m e m b r a n e

a n n u l u s i s c l e a r l v v i s u a l i z e d ( F i g . 5 - 2 4 C ) .

U s i n g a l a r g e s t a p e s c u r e t , c u r e t t h e s c u t u m f r o m

s u p e r i o r t o i n f e r i o r , t h u s a v o i d i n g i n j u r v t o t h e

o s s i c l e s ( F i g . 5 - 2 5 ) . V i s u a l i z e t h e s t a p e d i a l t e n d o n .

M a k e s u r e i t i s c l e a r l v i n s i g h t . A t t h i s p o i n t y o u a r e

r e a d y for a s t a p e d e c t o m y . I n s t e a d o f s e c t i o n i n g t h e

s t a p e d i a l t e n d o n ( w h i c h c a n b e d o n e , a s w e l l ) , t r y t o

lift i t a l o n g w i t h i t s p e r i o s t e u m w i t h t h e i n c u d o s t a -

p e d i a l j o i n t k n i f e , l e a v i n g i t a t t a c h e d t o t h e p e r i o s ­

t e u m o f t h e l o n g p r o c e s s o f t h e i n c u s ( F i g . 5 - 2 6 / 4 ) .

T h i s i s n o t a s i m p l e p r o c e d u r e . U s i n g t h e i n c u d o -

s t a p e d i a l j o i n t k n i f e , s e p a r a t e t h e j o i n t v e r y g e n t l y .

F r a c t u r e t h e f o o t p l a t e i n t h e m i d d l e w i t h a s t r a i g h t

p i c k ( F i g . 5 - 2 6 B ) . M o b i l i z e t h e s t a p e s , u s i n g s u p e r i o r -

t o - i n f e r i o r a n d i n f e r i o r - t o - s u p e r i o r m o v e m e n t s , a n d

r e m o v e it , h o o k i n g t h e j o i n t k n i f e t o t h e a r e a i m m e ­

d i a t e l y i n f e r i o r t o t h e c a p i t u l u m ( F i g . 5 - 2 6 C ) . T h e

r e m a i n i n g f o o t p l a t e p o r t i o n s a r e l i f ted g e n t l y w i t h a

H o u g h h o e ( F i g . 5 - 2 6 D ) . U s i n g t h e w i r e b e n d i n g d i e

0 . 0 0 5 s t a i n l e s s s t e e l a n d G e l f o a m , m a k e t h e p r o s ­

t h e s i s a s d e s c r i b e d i n F i g u r e 5 - 2 7 . P l a c e i t o v e r t h e

l o n g p r o c e s s o f t h e i n c u s a n d g e n t l y c r i m p — n o t t o o

t i g h t l y , n o t t o o l o o s e l y — a l l o w i n g i t s o m e m o b i l i t y

s i n c e e x c e s s i v e t i g h t n e s s m i g h t r e s u l t i n n e c r o s i s o f

t h e l o n g p r o c e s s o f t h e i n c u s . M a k e a T e f l o n p i s t o n

( R o s a l e s t e c h n i q u e ) a s d e s c r i b e d i n F i g u r e 5 - 2 8 . P l a c e

t h i s p i s t o n p r o s t h e s i s o v e r t h e l o n g p r o c e s s o f t h e

i n c u s a n d g e n t l y c r i m p it .

N o w r e m o v e t h e i n c u s . T r y t o m a k e a l o n g e r

p r o s t h e s i s o f s t a i n l e s s s t e e l w i r e a n d G e l f o a m t o

e x t e n d f r o m t h e m a l l e u s t o t h e o v a l w i n d o w ( F i g . 5 -

2 9 ) . U s e t h e i n c u s t o m a k e a s t r u t for u s e b e t w e e n

t h e m a l l e u s a n d t h e s t a p e s . S e c t i o n t h e s h o r t p r o c e s s

o f t h e i n c u s a n d dr i l l a n a c e t a b u l u m o v e r t h e b o d y

s o t h a t i t w i l l fit u n d e r t h e m a l l e u s . U s e a s m a l l g r a f t

t o c o v e r t h e o v a l w i n d o w .

A t t h i s p o i n t , w i t h t h e u s e o f a c u r e t o r v e r y s m a l l

b u r , c u r e t o r dr i l l t h e a t t i c i n o r d e r t o p e r f o r m a n

a t t i c o t o m y . U s e a W h i r l y b i r d t o p r o b e t h e a n t r u m .

Cochlear Implant (Mastoidotomy-Tympanotomy Approach)

Aim

T o p l a c e a n e l e c t r o d e i n t o t h e c o c h l e a b y s l i d i n g i t

t h r o u g h t h e r o u n d w i n d o w .

Highlights and Surgical Steps

1 . A c h i e v e g o o d v i s u a l i z a t i o n o f t h e m i d d l e e a r

a n d r o u n d w i n d o w n i c h e via a n e n d a u r a l a p p r o a c h

( L e m p e r t 1 i n c i s i o n ) .

2 . P e r f o r m a n a t t i c o t o m y .

3 . R e m o v e t h e i n c u s .

4 . E x p o s e t h e m a s t o i d c o r t e x a n d dr i l l a m a s t o i d -

o t o m y ( L e m p e r t I I i n c i s i o n ) .

5 . P e r f o r m a s m a l l p o s t a u r i c u l a r i n c i s i o n a n d dr i l l

a s e a t f o r t h e i n t e r n a l r e c e i v e r .

6 . T u n n e l t h e e l e c t r o d e f r o m t h e p o s t a u r i c u l a r

i n c i s i o n . o t h e m a s t o i d o t o m y i n t o t h e a n t r u m , m i d d l e

e a r , a n d r o u n d w i n d o w n i c h e .

7 . S e c u r e t h e i n t e r n a l r e c e i v e r i n p l a c e .

Text continued on ptigc 82

FIGURE 5-24

S u r g i c a l P r o c e d u r e s 7 7

Tympanosquamous suture

B

FIGURE 5-25

Ib Surhica! l'rocl'durl'SSuq~ical Procedures 79

B

Malleus to oval windowD

t--- 4 mm ---l

A

0.005 stajnJess steel wire

Gelfoam

-ff-......--.--,

FoolplateB

A

c

FIGURE o-B

8 0 S u r g i c a l P r o c e d u r e s

FIC'.URl-' 5-28.

S u r g i c a l P r o c e d u r e s

FIGURE 5-24

82 S u r g i c a l P r o c e d u r e s

Procedure

T h i s p r o c e d u r e i m p l i e s a n e n d a u r a l a p p r o a c h ,

e x p o s i n g b o t h t h e m i d d l e e a r a n d m a s t o i d c o r t e x .

O n c e t h e r o u n d w i n d o w n i c h e i s c l e a r l y e x p o s e d a n d

d e f i n e d , a n a t t i c o t o m y ( F i g . 5 - 3 0 A ) i s d o n e a n d t h e

i n c u s i s r e m o v e d . A s m a l l m a s t o i d o t o m y i s p e r ­

f o r m e d ( F i g . 5 - 3 0 C ) . T h i s o p e n i n g wi l l a l l o w p a s s a g e

o f t h e e l e c t r o d e i n t o t h e m i d d l e e a r t h r o u g h t h e

a n t r u m ( F i g . 5 - 3 0 E ) . T h e r e c e i v e r i s p l a c e d a s i n t h e

p o s t e r i o r t y m p a n o t o m y a p p r o a c h ; h o w e v e r , o n l y a

s m a l l p o s t a u r i c u l a r i n c i s i o n i s n e e d e d , a n d t h e e l e c ­

t r o d e i s t u n n e l e d a n t e r i o r l y t o w a r d t h e m a s t o i d o t ­

o m y .

S i n c e t h i s i s a t e m p o r a l b o n e d i s s e c t i o n , a n a t t e m p t

c a n b e m a d e t o p l a c e t h e r e c e i v e r , p e r f o r m i n g a

m a s t o i d o t o m y a n d p a s s i n g t h e e l e c t r o d e t h r o u g h t h e

a n t r u m a n d i n t o t h e r o u n d w i n d o w ( F i g . 5 - 3 1 ) . T h e

i n c u s m u s t b e r e m o v e d ( w h i c h h a s a l r e a d y b e e n

d o n e ) . A m a s t o i d o t o m y i s t h e c r e a t i o n o f a n o p e n i n g

i n t h e f o s s a m a s t o i d e a w i t h o u t p e r f o r m i n g a c o m ­

p l e t e c o r t i c a l m a s t o i d e c t o m y . T h e b o n e i s d r i l l e d i n

t h e d i r e c t i o n o f t h e a n t r u m b y v i s u a l i z i n g t h e a t t i c

a r e a d i r e c t l y t h r o u g h t h e m i d d l e e a r . I n o r d e r t o

a s c e r t a i n t h e l o c a t i o n o f t h e a n t r u m , a W h i r l y b i r d

c a n b e u s e d for d i r e c t p r o b i n g . E v e n i f a m a s t o i d o t -

o m v i s n o t p r e c i s e l y a c o r t i c a l m a s t o i d e c t o m y , t h e

o p e n i n g s h o u l d b e l a r g e e n o u g h ; a b l i n d , s m a l l

o p e n i n g i s d a n g e r o u s . T h e m a s t o i d o t o m y i t s e l f i s a

u s e f u l e x p l o r a t o r y too l f o r t h e a n t r u m w h e n b l o c k a g e

i s s u s p e c t e d o r i m p r o v e d a e r a t i o n o f t h e m i d d l e e a r

i s d e s i r e d . I n s e r t i o n o f t h e e l e c t r o d e t h r o u g h t h e

r o u n d w i n d o w i s t h e s a m e a s i n t h e p o s t e r i o r t y m ­

p a n o t o m y a p p r o a c h ; t h e e l e c t r o d e i s p a s s e d t h r o u g h

t h e o p e n i n g i n t o t h e c o c h l e a .

Transcanal Lahyrinthectomy

Procedure

V i s u a l i z e t h e m i d d l e e a r c a v i t y ( F i g . 5 - 3 2 ) . I d e n t i f y

t h e o v a l a n d r o u n d w i n d o w s a n d p r o m o n t o r y , a s

w e l l a s t h e f ac i a l n e r v e . H i e p u r p o s e o f t h i s p r o c e ­

d u r e i s t o d e s t r o y t h e l a b y r i n t h . T h e s t a p e s f o o t p l a t e

h a s b e e n r e m o v e d , a n d t h e v e s t i b u l e c o n t a i n i n g t h e

s a c c u l e a n d u t r i c l e i s e x p o s e d . B v t h e u s e o f a h o o k

o r H o u g h h o e , t h e s a c c u l e c a n b e d e s t r o y e d (F ig . 5 -

3 3 A ) . U s i n g t h i s s a m e r o u t e , t h e a m p u l e o f t h e

s u p e r i o r s e m i c i r c u l a r c a n a l c a n b e r e a c h e d a b o v e a n d

i n f ron t o f t h e fac ia l n e r v e , t h a t o f t h e p o s t e r i o r c a n a l

b e l o w a n d b e h i n d t h e n e r v e , a n d t h e a m p u ; e o f t h e

h o r i z o n t a l c a n a l i n f e r i o r l y b e n e a t h t h e n e r v t ( F i g . 5 -

3 3 / 1 , B ) . I n t h i s p r o c e s s , t h e u t r i c l e i s d e s t o y e d a s

w e l l . I t i s i m p o r t a n t t o s t a y w i t h i n t h e b o n y . o n l ' i n e s

a n d t o d e s t r o y o n l y t h e " m e m b r a n o u s l a b / r i n t h . "

I m m e d i a t e l y i n f e r i o r t o t h e v e s t i b u l e i s t h e i n t e r n a l

a u d i t o r y c a n a l , w h e r e t h e b o n y p l a t e i s q u i t e t h i n .

T h e f ac i a l n e r v e a l s o c a n b e i n j u r e d . T o c o m p e t e ' h e

p r o c e d u r e , d r i l l t h e p r o m o n t o r y a n d j o i n K i e o v a l

a n d r o t i n d w i n d o w s , e x p o s i n g t h e b e g i n n i n g o f t h e

b a s a l t u r n o f t h e c o c h l e a ( F i g . 5 - 3 3 C ) . A d d i t i o n a l

d r i l l i n g c a n b e d o n e a t t h i s p o i n t for p u r p o s e s o f

o r i e n t a t i o n t o t h e c o c h l e a r a n a t o m y . P l a c i n g a a e l e c ­

t r o d e v ia t h e b a s a l t u r n c a n g i v e t h e s u r g e o n a : l e a r e r

g r a s p o f t h i s p r o c e d u r e a n d i ts a n a t o m i c l o c a l o n .

A t t h i s p o i n t , a n i n s i d e - o u t m o d i f i e d rad ica ' . m a s ­

t o i d e c t o m y ( a t t i c o t o m y ) c a n b e p e r f o r m e d , , s d e ­

s c r i b e d e a r l i e r i n t h i s c h a p t e r .

A f t e r t h i s p r o c e d u r e , i t w i l l b e p o s s i b l e t o r e p e a t

s o m e o f t h e o p e r a t i v e p r o c e d u r e s d o n e w i t h t h e f irst

w e t b o n e . F o r t h e n e x t p r o c e d u r e s t w o w e t b o n e s

a r e r e c o m m e n d e d : o n e fo r t h e m i d d l e f o s s a a p p r o a c h

a n d o n e for t h e r e m a i n i n g a p p r o a c h e s .

Retrolabyrinthine Approach to the Cerebellopontine Angle

Aim

T o o b t a i n s u r g i c a l a c c e s s t o t h e c e r e b e l l o p o n t i n e

a n g l e a n d p r e s e r v e i n t e g r i t y o f t h e l a b y r i n t h .

Highlights

1 . C o m p l e t e r e m o v a l o f b o n e u p t o t h e p o s t e r i o r

s e m i c i r c u l a r c a n a l .

2 . S k e l e t o n i z a t i o n a n d m o b i l i z a t i o n o f t h e s i g r o i d

s i n u s t o a l l o w p o s t e r i o r r e t r a c t i o n .

3 . C o m p l e t e r e m o v a l o f b o n e f r o m t h e p o s t c t c i

f o s s a d u r a , s i n o d u r a l a n g l e , a n d p o s t e r i o r port io•> t f

t h e t e g m e n .

4 . R e m o v a l o f b o n e o v e r t h e p o s t e r i o r f o s s a d ira

p o s t e r i o r t o t h e s i g m o i d s i n u s .

B e f o r e b e g i n n i n g t h i s a p p r o a c h , a s m a l l s e g m n t

o t I V t u b i n g o r r e d r u b b e r c a t h e t e r s h o u l d b e p l a t e d

i n t h e i n t e r n a l a u d i t o r y c a n a l t o s i m u l a t e c r a r i.il

n e r v e s VII a n d V I I I . B o n e w a x o r g l u e wi l l h o l d i t i n

p o s i t i o n .

Surgical Procedures

FIGURE 5-W

s u r g i c a l P r o c e d u r e s

S u r g i c a l P r o c e d u r e s 8 5

Horizontal canal ampule

Common crus

Procedure

T h e i n i t i a l s t e p i n t h e r e t r o l a b y r i n t h i n e a p p r o a c h

i s a t h o r o u g h s i m p l e m a s t o i d e c t o m y a s d e s c r i b e d

e a r l i e r i n t h i s c h a p t e r . C l e a r i d e n t i f i c a t i o n o f t h e

p o s t e r i o r s e m i c i r c u l a r c a n a l i s e s s e n t i a l , a s t h i s i s t h e

a n t e r i o r l i m i t o f t h e d i s s e c t i o n a n d e x p o s u r e . H e n c e ,

i t i s i m p o r t a n t t o r e m o v e b o n e u p t o t h e c a n a l .

E x p o s u r e a l s o i s e n h a n c e d b y a d e q u a t e r e m o v a l o f

b o n e i n t h e i n f r a l a b y r i n t h i n e ce l l t r a c t . T h e s i g m o i d

s i n u s i s s k e l e t o n i z e d a n d m o b i l i z e d , i f t h i s h a s n o t

a l r e a d y b e e n c o m p l e t e d . T h e a u t h o r s p r e f e r t o l e a v e

a n i s l a n d o f b o n e o n t h e s i n u s ( B i l l ' s i s l a n d ) t o p r o t e c t

i t f r o m a c c i d e n t a l r u p t u r e w i t h a s h a f t o f t h e b u r o r

d u r i n g r e t r a c t i o n ; b o n e c a n b e c o m p l e t e l y r e m o v e d

f r o m t h e s i n u s i f s o d e s i r e d . B o n e c a n b e e i t h e r

c o m p l e t e l y r e m o v e d w i t h t h e d i a m o n d dr i l l o r

t h i n n e d t o e g g s h e l l t h i c k n e s s a n d r e m o v e d w i t h a

b l u n t i n s t r u m e n t .

F o l l o w i n g m o b i l i z a t i o n o f t h e s i g m o i d s i n u s , t h e

b o n e e v e r t h e p o s t e r i o r f o s s a d u r a a n d s i n o d u r a l

a n g l e ir- r e m o v e d i n t h e s a m e w a y . D u r a i s v e r y

f r a g i l e i n p r e p a r e d b o n e , a n d c a r e m u s t b e t a k e n n o t

t o t e a r i t . I t i s i m p o r t a n t t o r e m e m b e r t h a t t h e

s u p e r i o r p e t r o s a l s i n u s r u n s i n t h e s i n o d u r a l a n g l e ;

b l e e d i n g i n t h i s a r e a m u s t b e p r e v e n t e d . R e m o v a l o f

b o n e i s c o n t i n u e d u p t o t h e p o s t e r i o r s e m i c i r c u l a r

c a n a l . E x p o s u r e i s e n h a n c e d w i t h b o n e r e m o v a l c o n ­

t i n u e d a s h o r t d i s t a n c e i n t o t h e t e g m e n .

I t s h o u l d b e r e m e m b e r e d t h a t t h e p o s t e r i o r f o s s a

d u r a m u s t a l s o b e e x p o s e d p o s t e r i o r t o t h e s i g m o i d

86 Surgical Procedures Surgical Procedures 87

sinus to allow for better retraction. This is usually not possible in temporal bone specimens, as this bone is needed to hold bone in position.

Following decompression of the dura and sinus, the dura is opened with a sickle knife and Malis scissors. The incision lines are depicted in Figure 5-34/1. The lateral incision parallels the sigmoid sinus, running from superior to inferior, and runs just lateral to the endolymphatic sac in its inferior aspect. The second incision runs from lateral to medial and parallels the superior petrosal sinus. The dura is hinged at the posterior semicircular canal; the dura flap is draped over the canal. With retraction of the cerebellum (not present in specimen) and angling of the microscope anteriorly, good visualization of the cerebellopontine angle and cranial nerves V, VII, VIII, IX, X, and XI is afforded (Fig. 5 -34B) . For this demonstration, identification of the internal auditory canal marker should be accomplished.

Translabyrinthine Approach to the Internal Auditory Canal

Aim

To expose and open the internal auditory canal and identify the four cranial nerves contained within.

Higliliglits

1. Complete mastoidectomy and labyrinthectomy. 2. Identifying and outlining the internal auditorv

canal. 3. Opening into the internal auditorv canal; iden­

tifying Bill's bar and the transverse crest. 4. Identifying the superior and inferior vestibular

nerves, the cochlear nerve, and the facial nerve.

Procedure

The initial step in the translabyrinthine approach is the complete mastoidectomy and labyrinthectomy (described earlier). To help in later identification of the superior vestibular nerve, the medial wall of the ampulla of the semicircular canal is often preserved.

It is helpful to visualize the internal auditory canal as it traverses the temporal bone.

Several points should be remembered. The inter­nal auditory canal, as it runs anterior to posterior, starts away from the dissection; hence, at the poste­rior fossa dura it will be deeper or more medial than at the vestibule. There is a common wall between the vestibule and internal auditory canal. In other words, the medial wall of the vestibule represents the lateral wall of the internal auditory canal. A reference for the direction in which the canal runs is from the external genu to the sinodural angle.

Bone removal is continued medially following the labyrinthectomy. Again, it is important to remember that the canal becomes more medial (or deeper) as it approaches the posterior fossa dura. As the canal is approached a dark blue color will be seen, as in the blue lining of any hollow structure. Diamond burs are used at this point to decrease the risk of damage to important structures. It is important to skeletonize the internal auditory canal 180 degrees to allow adequate exposure and prevent bony overhangs.

Superiorly, the middle fossa dura is identified and followed medially. A thin layer of bone is left over the internal auditory canal. The "trench" that is developed extends from the facial nerve anteriorly to the posterior fossa dura posteriorly. It is important to remember that the superior petrosal sinus runs posterior superiorly in the sinodural angle; careful bone removal is required here. The inferior border of the internal auditory canal is now delineated. It is extremely important to be aware of and alert for the jugular bulb as soon as the posterior semicircular canal is removed in the labyrinthectomy. While usu­ally positioned low in the mastoid tip, the bulb may present as high as the posterior semicircular canal (Fig. 5-35/1) . Again, the internal auditory canal has a blue lining, and a trench is developed inferior to the canal. The inferior margin of this canal will be the jugular bulb. It is safest to begin at the posterior fossa junction and proceed medially and anteriorly. As the incision continues anteriorly, a small white discoloration in the bone will appear. This represents the cochlear aqueduct, which is an important land­mark. Extreme diligence is needed to identify this structure. Cerebrospinal fluid often is released when the aqueduct is entered. Anterior to this lie cranial nerves IX, X, .and XI. Again, bone should be removed for 180 degrees around the internal auditory canal. The bone overlying the canal is thinned to eggshell thickness; it can then be carefully cracked with a blunt instrument and removed in one piece. The dura is best opened inferiorly to protect the facial nerve.

S u r g i c a l P r o c e d u r e s

FIGURE 5-35.

9 0 S u r g i c a l P r o c e d u r e s

T o l o c a t e t h e v a r i o u s n e r v e s i n t h e i n t e r n a l a u d i ­

t o r y c a n a l , t h e f ac i a l n e r v e m u s t f irst b e i d e n t i f i e d a s

i t r u n s t h r o u g h i t s l a b y r i n t h i n e c o u r s e ( F i g . 5 - 3 5 B ) .

W i t h t h e u s e o f s m a l l d i a m o n d b u r s , t h e fac ia l n e r v e

c a n b e s k e l e t o n i z e d ( b l u e - l i n e d ) f r o m t h e a r e a o f t h e

s u p e r i o r s e m i c i r c u l a r c a n a l a m p u l l a t o t h e f irst g e n u .

A g a i n , a t r e n c h c a n b e d e v e l o p e d b e t w e e n t h e n e r v e

a n d t e g m e n . T h e s u p e r i o r s e m i c i r c u l a r c a n a l a m p u l l a

h e l p s t o i d e n t i f y t h e s u p e r i o r v e s t i b u l a r n e r v e ; i t s

m e d i a l w a l l r e p r e s e n t s t h e l a s t r e m a i n i n g b o n e o v e r

t h e s u p e r i o r v e s t i b u l a r n e r v e a t i t s t e r m i n a t i o n i n t h e

a m p u l l a . U p o n r e m o v a l o f t h i s b o n e , t h e s u p e r i o r

v e s t i b u l a r n e r v e i s i d e n t i f i e d . A 1 - m m h o o k c a n b e

u s e d t o p e r f o r a t e B i l l ' s b a r , w h i c h i s t h e r i d g e o f

b o n e s e p a r a t i n g t h e f ac i a l a n d s u p e r i o r v e s t i b u l a r

n e r v e s . T o p r e v e n t d a m a g e t o t h e f ac i a l n e r v e , t h e

h o o k s h o u l d n e v e r b e i n s e r t e d i n t o t h e f a l l o p i a n

c a n a l . T h e s u p e r i o r v e s t i b u l a r n e r v e i s t h e n a v u l s e d

( F i g . 5 - 3 6 A ) . A f t e r p r o p e r i d e n t i f i c a t i o n o f B i l l ' s b a r ,

i t i s s a f e t o r e m o v e e v e r y t h i n g l a t e r a l t o t h i s r i d g e o f

b o n e .

N e x t , t h e t r a n s v e r s e c r e s t s h o u l d b e i d e n t i f i e d . A

b o n y p r o m i n e n c e t h a t l i e s i n f e r i o r t o t h e s u p e r i o r

v e s t i b u l a r a n d fac ia l n e r v e s , i t d i v i d e s t h e i n t e r n a l

a u d i t o r v c a n a l i n t o s u p e r i o r a n d i n f e r i o r p o r t i o n s .

I m m e d i a t e l y i n f e r i o r t o t h e t r a n s v e r s e c r e s t i s t h e

i n f e r i o r v e s t i b u l a r n e r v e . M e d i a l t o t h i s l i e s t h e c o c h ­

l e a r n e r v e ( F i g . 5 - 3 6 6 ) . T h i s c o m p l e t e s t h e e x p o s u r e

a n d i d e n t i f i c a t i o n o f t h e i n t e r n a l a u d i t o r v c a n a l .

Transcochlear Approach to the Skull Bone

Aim

T o g a i n a c c e s s t o t h e c e r e b e l l o p o n t i n e a n g l e m e d i a l

t o t h e p o r u s a c u s t i c u s a n d / o r a n t e r i o r t o t h e b r a i n ­

s t e m . A c c e s s t o t h i s a r e a i s l i m i t e d w i t h a c o n v e n ­

t i o n a l s u b o c c i p i t a l a p p r o a c h b y t h e c e r e b e l l u m a n d

b r a i n s t e m ; i n t h e t r a n s l a b y r i n t h i n e a p p r o a c h i t i s

l i m i t e d b y t h e f ac i a l n e r v e i n t h e t y m p a n u m a n d

m a s t o i d .

Highlights

1 . C o m p l e t e m a s t o i d e c t o m y a n d l a b v r i n t h e c t o m v .

2 . M o b i l i z a t i o n o f t h e f ac i a l n e r v e w i t h i n t h e e n t i r e

f a l l o p i a n c a n a l .

3 . T r a n s p o s i t i o n o f t h e f ac i a l n e r v e p o s t e r i o r 1 " , .

4 . R e m o v a l o f t h e f a l l o p i a n c a n a l a t a l l t u r n s o f

t h e c o c h l e a .

5 . A n t e r i o r l i m i t b e c o m e s t h e i n t e r n a l c a r o t i c . a r ­

t e r y .

Procedure

T h e t r a n s c o c h l e a r a p p r o a c h i s a n a n t e r i o r e ; l e - i -

s i o n o f t h e t r a n s l a b y r i n t h i n e a p p r o a c h t o t h e e t e -

b e l l o p o n t i n e a n g l e . A g a i n , t h e in i t i a l s t e p s a e a

c o m p l e t e m a s t o i d e c t o m y a n d l a b y r i n t h e c t o m y a s

d e s c r i b e d e a r l i e r . T h e i n t e r n a l a u d i t o r y c a n a l i s t h e n

o u t l i n e d , a n d t h e f a c i a l n e r v e i s i d e n t i f i e d a s i t e n t e r s

t h e l a b y r i n t h i n e s e g m e n t o f t h e f a l l o p i a n c a n a l . Th i s

i s f o u n d b y u s i n g t h e a m p u l l a o f t h e s u p e r i o r s e m i ­

c i r c u l a r c a n a l a s a l a n d m a r k f o r t h e s u p e r i o r ve< f ib­

u l a r n e r v e . W i t h a s m a l l d i a m o n d b u r , t h e t e g m e a i s

f o l l o w e d m e d i a l l y i n t h i s a r e a t o d e v e l o p t h e s u p e i o r

a s p e c t o f t h e i n t e r n a l a u d i t o r y c a n a l . T h e f ac i a l n e r v e

w i l l b e b l u e - l i n e d a s i t l e a v e s t h e i n t e r n a l a u d i t >ry

c a n a l a n d b e g i n s i t s c o u r s e i n t h e l a b v r i n t h i n e ' I ' g -

m e n t o f t h e f a l l o p i a n c a n a l ( F i g . 5 - 3 7 / 1 ) .

T h e n e x t s t e p i s t o c o m p l e t e l y s k e l e t o n i z e h e

f ac i a l n e r v e f r o m t h e s t y l o m a s t o i d f o r a m e n t o h e

i n t e r n a l a u d i t o r y c a n a l . A n e x t e n d e d fac ia l r e c e s s

o p e n i n g i s m a d e ( F i g . 5 - 3 7 B ) . A f t e r a d e q u a t e t h n -

n i n g o f t h e p o s t e r i o r e x t e r n a l a u d i t o r y c a n a l , a c u t t ; i g

o r d i a m o n d b u r i s u s e d t o e n l a r g e a n a r e a i m m e d i ­

a t e l y i n f e r o r t o t h e f o s s a i n c u d i s a n d l a t e r a l t o 1 \ e

t a c i a l n e r v e a t t h e b e g i n n i n g o f i t s m a s t o i d s e g m e t t .

I t i s i m p o r t a n t to u s e as l a r g e a dr i l l as p o s s i b l e o

p r e v e n t t u n n e l i n g a n d p o o r v i s u a l i z a t i o n . I n a t r e

f ac i a l r e c e s s , c a r e m u s t b e t a k e n n o t t o d i s r u p t t E e

c h o r d a t y m p a n i ( l a t e r a l l i m i t ) a n d t h e t v m p a n i c m e m ­

b r a n e . T h e s e s t r u c t u r e s wi l l b e r e m o v e d i n t h i s

a p p r o a c h s o t h a t d i s s e c t i o n m a v b e a c c o m p l i s h e d

m o r e s w i f t l v . A f t e r t h e o p e n i n g i s m a d e i n t o t h e

m i d d l e e a r , t h e i n c u d o s t a p e d i a l j o i n t i s v i s u a l i z e d

a n d s e p a r a t e d . T h e i n c u s i s r e m o v e d t h r o u g h th•!

a t t i c . T h e fac ia l r e c e s s i s t h e n e n l a r g e d s u p e r i o r ! r

t h r o u g h t o t h e f o s s a i n c u d u s a n d i n f e r i o r l y t o t h '

l e v e l o f t h e f l o o r o f t h e t y m p a n u m .

T h e e x t e r n a l a u d i t o r y c a n a l i s t h e n r e m o v e d w i l l '

a r o n g e u r t o i m p r o v e v i s u a l i z a t i o n o f t h e f ac i a l n e r v e

T h e a n t e r i o r b u t t r e s s i s d r i l l e d t o t h e l e v e l o f th'.

m i d d l e f o s s a t e g m e n a n d i n f e r i o r l y a s a s m o o t l

t r a n s i t i o n t o t h e f l o o r o f t h e t y m p a n u m i s a c c o m ­

p l i s h e d . W i t h t h e d i a m o n d d r i l l , t h e fac ia l n e r v e

t h e n s k e l e t o n i z e d c o m p l e t e l y w i t h i n t h e t e m p o r e

b o n e . T h e c h o r d a t y m p a n i h a s a l r e a d y b e e n s a c r i ­

f i c e d . W h e n t h e b o n e h a s b e e n c o m p l e t e l y r e m o v e d ,

S u r g i c a l P r o c e d u r e s

FIGURE 5-36

92 Surgical Procedures

the greater superficial petrosal nerve is cut at its origin from the geniculate ganglion (Fig. 5-37C) . This frees the facial nerve from all attachments in the temporal bone. It is then carefully reflected poste­riorly out of its bony bed.

Any remaining tympanic membrane is now re­moved, as well as any skin remaining on the anterior part of the external auditory canal. The anterior external auditory canal and any bony overhang are drilled to the level of the temporomandibular joint. The stapes is also removed at this point. Starting with the basal coil, the cochlea is completely drilled out, as well as the remnant of the fallopian canal (Fig. 5 -38B) . (It is good practice to follow the coch­lea's coils to gain a better understanding of its anat­omy.) Bone removal is carried forward to the septum that lies between the internal carotid artery and anterior wall of the basal coil. The internal carotid artery can be blue-lined with the diamond drill, much as the jugular bulb is blue-lined in the translabyrin­thine approach. Interiorly, bone removal extends to the inferior petrosal sinus and jugular bulb. Superi­orly, the superior petrosal sinus and tegmen are followed medially to Meckel's cave (Fig. 5 -38C) . Medially, removal of bone continues to the lateral clivus. When bone removal has been completed, a large window covered by dura (bounded superiorly by the superior petrosal sinus and interiorly by the jugular bulb and inferior petrosal sinus, with its apex just below Meckel's cave and the internal carotid artery located anteriorly) is created into the skull bone. If the dura is still intact, this window can be opened posterior to the internal auditory canal and extended as far forward as needed for exposure. Cuts may run medially, anteriorly, and parallel to the superior petrosal sinus and jugular bulb.

In an actual procedure, the dural defect is packed with abdominal fat and the external ear canal is sewn shut to prevent postoperative leakage of cerebrospi­nal fluid.

Middle Fossa Approach to the Internal Auditory Canal

Aim

To expose the floor of the middle cranial fossa and identify the structures contained within, including the cochlea, arcuate eminence, and contents of the internal auditory canal.

Surgical Procedures 93

Procedure

When practicing this approach in the laboratory,

placement of the bone within the bone cup is impor­

tant. Imagine a patient lying supine with the head

turned to one side; the surgeon sits at the head of

the patient and looks down on the middle cranial

fossa floor through the craniotomy opening (de­

scribed earlier). Hence, the bone needs to be placed

in the bone cup so that the surgeon looks directly

down upon the floor of the middle fossa (Fig. 5-

39 /1) . If the dura is still intact, it should be stripped

from the exposed floor. As the dura is being elevated,

the middle meningeal artery will be found anteriorly

as it exits from the foramen spinosum. This repre­

sents the anterior limit of an adequate exposure.

After all the dura has been removed, the floor should

be studied. Laterally, where the floor rises to the

pars squamosa, the tegmen overlies the aerated mas­

toid and; the epitympanum. The eustachian tube

(covered by thin bone) is located anterior to the

epitympinum. Posteriorly, the floor of the middle

fossa drops into the posterior fossa. Along this ridge

runs the superior petrosal sinus within the reflected

dura. Approximately" 1 cm medial to the middle

meningeal artery lies the greater superficial petrosal

nerve, which runs in a posterior to anterior direction

as it leaves the geniculate ganglion. This nerve is an

important landmark; it can be followed back to find

the geniculate ganglion and the facial nerve. In

approximately 5% of cases the geniculate ganglion

will not be covered by bone. Another important

landmark is the arcuate eminence of the superior

semicircular canal; usually an obvious feature, it may

occasionally be indistinct. It is medial to the aerated

bone of the mastoid and epitympanum, and appears

as a rounded prominence. It must be remembered

that every temporal bone will have its own unique

middle fossa topography; no consistent landmark

Highlights

1. To decompress the labyrinthine segment of the

facial nerve or remove facial nerve lesions.

2. To remove small intracanalicular acoustic tu­

mors in art attempt to preserve residual hearing.

3. To rupair large defects of the tegmen and dura

that have Resulted in cerebrospinal fluid leaks.

4. To section the superior and inferior vestibular

nerves and retain hearing.

Surgical Procedures

FIGURE 5-38.

Surgical Procedures

FIGURE 5-39.

96 Surgical Procedures

Incus

| Facial nerve

In' vestibular nerve

FIGURE 5-10.

Surgical Procedures 97

can be relied upon. Familiarity with the middle fossa is accomplished only with repeated inspection and dissection. The major landmarks of the middle fossa have now been identified, including the middle me­ningeal artery, the greater superficial petrosal nerve with its facial hiatus, and the arcuate eminence.

Dissection begins with positive identification of the facial nerve. The greater superficial petrosal nerve is followed back to the facial hiatus, where it enters and joins the geniculate ganglion. With a large dia­mond bur and suction irrigation to avoid heat gen­eration and bone dust accumulation, the thin bone overlying the geniculate ganglion is removed (Fig. 5 -39B) . Here the facial nerve turns slightly posterior and inferior as it runs into its tympanic course. The epitympanum may be opened to expose the head of the malleus, tensor tympani, and cochleariform proc­ess. The cochleariform process is the limit to which the facial nerve can be adequately decompressed by this, approach. Following this, the labyrinthine seg­ment of the facial nerve is exposed; this is a very short segment running from the geniculate ganglion to the lateral end of the internal auditory canal. Care must be taken not to enter the ampulla of the semicircular canal, which lies only a few millimeters posterior, or the cochlea, only a few millimeters anterior. This segment of the facial nerve courses almost parallel to the plane of the semicircular canal. A diamond bur is needed to work in this limited space. Bone is removed medially following the course of the facial nerve, which runs in a posterior and inferior (deeper) direction. When the posterior fossa

is reached (medially), the exposure can be widened because the semicircular canal courses posteriorly and the dissection at this point is medial to the cochlea. As the edge of the posterior fossa is reached, remember that the superior petrosal sinus lies in this dural reflection. At this point obtain wide exposure of the internal auditory canal. By carefully removing the final eggshell thinness of bone, the contents of the canal may be identified. The facial nerve occupies the anterosuperior compartment, with the superior vestibular nerve immediately behind in the postero-superior aspect (Fig. 5 -39C) . At the lateral end of the canal is Bill's bar, the ridge of bone separating these two nerves. Here the superior vestibular nerve runs to the ampulla of the semicircular canal. Immediately below the facial nerve lies the cochlear nerve, and the inferior vestibular nerve lies beneath the superior vestibular nerve. These represent the anteroinferior and posteroinferior compartments respectively.

For the sake of completeness, the following struc­tures should be found and followed in their courses. This will help to further the understanding of tem­poral bone anatomy in a three-dimensional view (Fig. 5 - 4 0 ) . Slightly lateral to the greater superior petrosal, the eustachian tube runs medially from the middle ear cavity to the nasopharynx. Upon dissection of the eustachian tube, the carotid artery may be found on the inferomedial floor of the tube; it courses horizontally from the middle ear to the cavernous sinus. The semicircular canal and cochlea should be entered and followed to gain a clear understanding of their positions within the temporal bone.

SECTION III i

General Principles and Approaches

CHAPTER 6 Operating Room Principles and General Concepts Evaluation

All patients should have a complete history ob­tained and be given a physical examination. Al­though proper surgical indications and adequate lab­oratory studies are essential, their discussion is beyond the scope of this chapter. A complete assess­ment of the patient's general conditions, as well as of the otologic problem itself, is to be made. It should be remembered that the ear is not an isolated organ; it interrelates anatomically and functionally with other organs and systems—for example, the naso­pharynx and nasal cavity—that must be evaluated in detail. The local conditions of the ear, including the skin of the pinna, the ear canal, middle ear mucosa, and so forth, must be improved as much as possible before surgery.

An otologic evaluation includes a number of basic tests in addition to the history and physical exami­nation. A recent complete audiogram that includes pure tones and speech discrimination is essential. Equally important is confirmation of the results by the surgeon, utilizing tuning forks.

Radiologic studies include conventional mastoid x-rays supported by tomograms, computed tomo­graphic scans, magnetic resonance, and other imag­ing modalities, depending on specific needs such as in cases of retrocochlear lesions, complications of otitis media, and congenital atresia. Specific indica­tions of such studies will not be discussed here except to mention that conventional x-rays remain valuable

and essential in many cases, providing information on mastoid aeration, the position of the sigmoid sinus, anc other details. X-rays must be available in the operafng room. A number of additional tests are used, su< "i as BAER (brainstem auditory evoked responses;, electrocochleography, promontory stim­ulation, and others, the indications for which are outside the scope of this atlas. The essential concept in this section is that the patient must be evaluated from a general as well as a local standpoint, and that tests serve the purpose of screening, ruling out, or confirming specific questions in the mind of the surgeon. They are not a "routine blanket ordered according to trends," nor are they intended to replace common sense and clinical acuity.

Patient Consent

As important as informed consent is from a legal standpoint, it is much more important in that it provides the patient with information. It is essential that the patient (or his or her parents) be aware of the rationale for and purpose of the surgical proce­dure. Is tlje aim reconstruction of the ossicular chain? Is it eradication of disease? What are the chances of success and the risks involved?

A well-informed patient is the best guarantee of success. I.iformation on the postoperative course and care is also essential and should be provided by the surgeon. Commercially printed instructions are very

102 Operating Room Principles and General Concepts

helpful; however, they do not approach the useful­

ness of instructions printed by the surgeon.

Anesthesia

Most otologic procedures can be performed under local anesthesia, with or without sedation. The de­cision will depend on the specific case and the surgeon's judgment and common sense. It should be remembered that a general anesthetic usually carries a small risk, at times comparable with that of local procedures under sedation. If a local anesthetic is to be used, it is important to know the innervation of the area to be anesthetized. (See the chapters on anatomy and general surgical approaches.) Different agents are utilized; the authors usually use lidocaine (Xylocaine) 1% with 1:100,000 epinephrine in both local and general anesthesia cases, since epinephrine exerts a vasoconstrictive effect essential for micro­scopic surgery. The maximum safe dose of lidocaine is 3 mg/kg without epinephrine and 7 mg/kg with epinephrine. In cases of myringotomies and tubes, iontophoretic anesthesia is a useful method in the office. It is based on a battery-operated unit (ionto­phoretic applicator) that generates a constant direct current, allowing ion transfer of a local anesthetic (placed in the ear canal) into the ear canal and tympanic membranes. Because it does not require an injection it is verv well accepted by some patients.

Antibiotics

The use of antibiotics is a controversial a b j e c t that will not be dwelled upon here. The author; use them prophylactically when there is a risk that n f e i -tion will extend into the inner ear or intracrajiially, compromise the survival of a graft or reconstructive procedure, or spread locally—for example, 6 ths auricular cartilage. When antibiotics are used; it is immediately before, during, and after the operation. In chronically draining ears the authors tend to star' antibiotic therapy several days prior to the procedure Use of antibiotics does not mean that strict aseptic techniques are disregarded; they are used only when there are additional risks in spite of a flawless .ech-nique that includes asepsis, meticulous hemoslasis, and gentleness with tissues.

Equipment and Procedures

The operating table must be comfortable but dard enough to allow for resuscitation procedure; if needed. It should be easily adjustable so that it can be raised or lowered or the patient placed in a Trendelenburg or reverse Trendelenburg position (Figs, 6 -1 , 6 -2 ) . The headpiece should be separable in order to change the position of the patient's head independently from the rest of the table (Fig. f -3) .

Operating Room Principles and General Concepts

FIGURE 6-2.

At times a simple "donut" will suffice; in general,

however, a Juers head holder is more useful, allow­

ing adjustments in angulation of the head as needed

(Figs. 6 - 4 , 6 -5 ) . The patient's head should be taped

to the head holder (which in turn is taped to the

head of the table) and moved with the holder as a

unit (Fig. 6 - 6 ) . The patient lies supine with the head

turned and lowered in order to bring the external

auditorv canal, which has a bonv orientation that is

downward and forward, into a nearly vertical posi­

tion.

Preparation of the Skin

The skin is prepared after shaving the hair. Shav­

ing of the hair is done with a dry razor blade at the

time of surgery, avoiding any lacerations of the skin.

Enough ,:air is shaved to provide a clean operative

field For i postauricular approach the authors shave

an area of approximately 2.5 cm. If a large flap is to

be raisec. (for example, for a postauricular cochlear

implant)'more hair is shaved. For an endaural ap-

F1GURE 6-3.

A headpiece that can be separated

from the table is useful.

104 O p e r a t i n g R o o m P r i n c i p l e s a n d G e n e r a l C o n c e p t s

FIGURES 6-4, 6-5. A Jucrs head holder allows neuverahilitv.

p r o a c h 0 . 5 c m o f h a i r s u p e r i o r l y a l o n g t h e s u p e r i o r

he l ix will suf f ice . A g e r m i c i d a l s o a p a n d s o l u t i o n

s u c h a s p o v i d o n e - i o d i n e ( B e t a d i n e ) o r h e x a c h l o r o -

p h e n e ( p H i s o H e x ) i s u s e d . W h i c h e v e r a g e n t i s s e ­

l e c t e d , t h e s c r u b s h o u l d b e for t en m i n u t e s a n d t h e

s o l u t i o n w i p e d d r y b e f o r e s t e r i l e d r a p e s a r e a p p l i e d .

T h e e a r c a n a l i s c l e a n s e d w i t h a s o l u t i o n s u c h a s

h y d r o g e n p e r o x i d e o r i r r i g a t e d w i t h s a l i n e , o r b o t h .

T h e o p e r a t i v e field i s i s o l a t e d w i t h s t e r i l e d r a p e s ,

a v o i d i n g e x c e s s i v e b u l k t h a t w o u l d c o m p r o m i s e m o ­

bi l i ty . T h e " h a n g i n g d r a p e s " a r e c l a m p e d t o g e t h ;

i n o r d e r t o a l l o w t h e s u r g e o n ' s l egs t o fit c o m f o r t a h : )

u n d e r t h e h e a d o f t h e tab le w i t h o u t i n t e r f e r e n c e .

Foreign Body Reaction

P a r t i c l e s c o n t a i n e d in g l o v e s ( p o w d e r ) , a pro: ;

t h e s i s , o r s u r g i c a l i n s t r u m e n t s c a n c a u s e i n f l a m m a

O p e r a t i n g R o o m P r i n c i p l e s a n d G e n e r a l C o n c e p t s 105

FIGURE 6-6.

The patient's head is taped to the head holder.

t o r y r e a c t i o n s t h a t a r e p o t e n t i a l l y h a r m f u l . I t i s a

g o o d h a b i t t o k e e p a s t e r i l e s o l u t i o n a n d a m o i s t

t o w e l t o r i n s e a n d c l e a n t h e s u r g i c a l g l o v e s b e f o r e

i n i t i a t i n g s u r g e r y . T h e s c r u b n u r s e s h o u l d h a v e o n

his o r h e r tab le a c o n t a i n e r w i t h s a l i n e i n o r d e r t o

c l e a n t h e i n s t r u m e n t s a n d p r o s t h e s i s p r i o r t o u s e .

I n s t r u m e n t s s h o u l d b e r i n s e d m e t i c u l o u s l y a f t e r t h e

u s e o f s t e r i l i z i n g c h e m i c a l s , s i n c e t h e s e c a n b e v e r y

d a m a g i n g t o t i s s u e s .

Positioning of the Surgical Team

T h e surgeon m u s t be in a c o m f o r t a b l e a n d s t a b l e

p o s i t i o n , w i t h b o t h feet o n t h e f loor , a n d w i t h t h e

b a c k s u p p o r t e d b y a c h a i r t h a t c a n b e m o v e d e a s i l y

( b y t h e s u r g e o n ) w h i l e r e t a i n i n g its p o s i t i o n . T h e

p a t i e n t m u s t b e p l a c e d s o t h a t t h e s u r g e o n i s n o t

b e n t o r f o r c e d i n t o u n c o m f o r t a b l e p o s i t i o n s . T h i s i s

u s u a l l y a c h i e v e d b y p o s i t i o n i n g t h e h e a d o f t h e

o p e r a t i n g t a b l e v i r t u a l l y o v e r t h e s u r g e o n ' s l a p , w i t h

t h e s u r g e o n c a p a b l e o f " c o m f o r t a b l y w r i t i n g o n a

d e s k " w h i l e l o o k i n g t h r o u g h t h e m i c r o s c o p e .

T h e surgical team i s of t h e u t m o s t i m p o r t a n c e . A

s u c c e s s f u l s u r g i c a l p r o c e d u r e r e p r e s e n t s t h e c o m ­

b i n e d e f f o r t s o f a t e a m o f s u r g e o n s , a n e s t h e s i o l o g i s t s ,

a n d s c r u b a n d c i r c u l a t i n g n u r s e s . N o m a t t e r h o w

ski l led t h e s u r g e o n , h i s o r h e r w o r k i s n o t p o s s i b l e

w i t h o u t a sa fe ly a n d a d e q u a t e l y a n e s t h e t i z e d o r

s e d a t e d p a t i e n t ; n o m a t t e r h o w ski l led t h e a n e s t h e ­

s i o l o g i s t , a d e q u a t e a n e s t h e s i a will n o t b e p o s s i b l e i f

t h e s u r g e o n d o e s n o t i n f o r m h i m o r h e r o f t h e

m o m e n t o f i n j e c t i o n o f e p i n e p h r i n e , m o b i l i z a t i o n o f

t h e h e a d o f t h e p a t i e n t , e l e v a t i o n o f t h e o p e r a t i v e

t a b l e , o r o t h e r p r o c e d u r e s . T h e s a m e r u l e s a p p l y i n

p r i n c i p l e for t h e c i r c u l a t i n g a n d s c r u b n u r s e s . T h e

p r e c e p t o f t h i s c h a p t e r i s t h a t i n s u r g e r y , t e a m w o r k

y i e l d s b e t t e r r e s u l t s t h a n " w o n d e r m a n " o r " w o n d e r

w o m a n " a l o n e .

T h e a u t h o r s ' p o s i t i o n i n g o f t h e t e a m a n d i n s t r u ­

m e n t s i n t i e o p e r a t i n g r o o m i s s h o w n i n F i g u r e 6 -

7 . T h e s c r u b n u r s e i s a t t h e r igh t o f t h e s u r g e o n a n d

t h e a s s i s t a n t i s a t t h e left. O t h e r s u r g e o n s p r e f e r

d i f f e r e n t s e t u p s . T h e b e s t p o s i t i o n i s o n e t h a t p r o ­

v i d e s t h e i i o s t c o m f o r t a n d e f f i c i ency t o a p a r t i c u l a r

t e a m .

Instruments

T h e operating microscope o b v i o u s l y m u s t be b i n o c ­

u l a r w i t h a foca l l e n g t h o f a t l e a s t 2 0 c m . T h e a u t h o r s

p r e f e r t o u s e t h e 2 5 - c m l e n g t h ; i t p r o v i d e s a r a n g e o f

m a g n i f i c a t i o n f r o m 6 X to 40 X , w i t h 6 x , 10 x , a n d

1 6 X t h e m o s t c o m m o n l y u s e d . A l o n g w i t h g o o d

l ight ( e i t h e r b u l b o r f i b e r o p t i c ) , i t r e q u i r e s g o o d

h a n d l i n g ab i l i ty . B o t h t h e s u r g e o n a n d t h e s c r u b

n u r s e m u s t b e f a m i l i a r w i t h t h e d i f f e r e n t k n o b s t h a t

p r o v i d e m a n e u v e r a b i l i t y . T h e a u t h o r s p r e f e r t o u s e

a n a n g l e d e y e p i e c e t h a t p r o v i d e s a n a n g l e o f 4 5

d e g r e e s a n d a l l o w s a m o r e c o m f o r t a b l e h e a d p o s i t i o n

for t h e s u r g e o n (F ig . 6 - 8 ) .

Operating Room Principles and General Concepts 107

urnmiit

I I

FIGURE 6-8 . The eyepiece angles (IF A microscope.

In spite of the many theoretical advantages of fully

automated microscopes (except for their price), the

classic Zeiss OPM1-1 or one of its equivalents (for

example, Vasconcellos) allows better maneuverability

and is less cumbersome to operate in ear surgery.

Again, this is a matter of preference; the point is

made because it is not unusual for the "starting

surgeon in practice" to be talked into buying a fully

automated, "state of the art" piece of equipment.

The position of the microscope is essential. The

arms should be at a 90-degree angle, which permits

a full range of motion (Figs. 6-9, 6-10) . In the case

of the OPM1-1 the "longer leg" of the pedestal should

point toward the patient's shoulder on the operated

side. The side viewer (teaching lens) is placed at the

left side; if possible a video camera is attached. This

allows the operating team to be aware of the proce­

dure, anticipate the use of instruments, and even

maintain a permanent record of the operation. A

suitable sterile drape of either cloth or disposable

plastic must be used (Fig. 6 -11) . For insertion of PE

tubes, rubber handles for focusing and magnification

are useful. If they are not available, a sterile towel

will suffice.

A variety of drills are commercially available. A

high-speed drill should suffice, provided that it is a

durable instrument capable of withstanding contin­

uous use. At least two drills should be available in

the operating room. The drill handles should be light

and easy to manipulate; the instrument should have

several speeds, including reverse and forward. Con­

trol by a foot pedal is preferable since handle-con­

trolled drills tend to have more vibration. The reverse

speed is useful for saucerizing small bleeding points

in the mastoid and bony ear canal. It is also important

that both the surgeon and scrub nurse should be

able to assemble and operate the drill. Different metal

burs, usually made out of tungsten or steel, are

available. Rounded burs work best for otology; they

can be of six or eight teeth. In general, burs with

more teeth accumulate more debris and are less

effective; however, a bur full of debris is useful in

areas requiring gentle work, and is similar in this

regard to a diamond bur (a metal bur coated with

diamond powder) . Burs must be sharp; dulling leads

to overheating. The authors favor burs with regular

shafts over those with special hooks, which in prac­

tice limit ;(he surgeon to particular brands; the more

universal the drill, the better. Sizes of burs vary

according'to need (discussed in specific chapters).

The "suction irrigation" feature is commonly used

today. Drills with continuous irrigation (variable

flow) are available, and are useful in avoiding drilling

over "dry bone," which promotes overheating and

necrosis. The authors prefer to use intermittent irri­

gation with a bulb syringe to provide moisture as

needed, thus avoiding the visual distortion that oc­

curs with "underwater drilling." Again, the purpose

is to avoid heating and necrosis of bone; that is best

achieved in a manner that is efficient for the surgeon.

Good suction is essential. The tubing should be

flexible, soft but not collapsible, and not too rigid,

so that it is easy to handle. A No. 5 suction tip is

used for cleansing the ear canal, a No. 20 for raising

flaps and for middle ear work, and a No. 24 for work

in the oval window. The authors prefer fenestrated

O p e r a t i n g R o o m P r i n c i p l e s a n d G e n e r a l C o n c e p t s 109

FIGURE 6-11. A disposable sterile plastic drape has been used with this microscope, which has a video camera attached.

h a n d l e s , w h i c h a l l o w c o n t r o l o f t h e d e g r e e o f s u c t i o n ;

s o m e s u r g e o n s p r e f e r t o c o n t r o l t h e d e g r e e o f s u c t i o n

w i t h a foo t c o n t r o l . F o r d r i l l i n g , l a r g e r s u c t i o n t i p s

a re u s e d ( N o . 7 to N o . 9 F r e n c h ) . A s y r i n g e for f o r c e d

i r r i g a t i o n , a s w e l l a s a w i r e t o c l e a n t h e s u c t i o n t i p ,

s h o u l d b e a v a i l a b l e . S m a l l s p o n g e s o r c o t t o n b a l l s

s h o u l d b e u s e d a t t h e s u c t i o n t ip w h e n w o r k i n g o v e r

g ra f t s o r p r o s t h e s e s t h a t c a n b e l o o s e n e d o r d i s l o d g e d

b y t h e s u c t i o n . ( C o t t o n m u s t n o t b e left i n t h e e a r

s i n c e i t i s a g u a r a n t e e o f i n f e c t i o n . ) T h e a u t h o r s '

u s u a l i n s t r u m e n t s e t u p i s s h o w n i n F i g u r e s 6 - 1 2 a n d

6 - 1 3 .

S t a n d a r d c a u t e r y u n i t s w i l l n o t b e d e s c r i b e d ; su f ­

f i c e i t t o m e n t i o n t h a t t h e a u t h o r s r o u t i n e l y u s e a

m o n o p o l a r u n i t , b u t for c a s e s o f a c o u s t i c n e u r o m a

o r i n w h i c h w o r k i s t o b e d o n e n e a r t h e f ac i a l n e r v e

a b i p o l a r u n i t s h o u l d b e a v a i l a b l e , b o t h t h e s u c t i o n

a n d c a u t e r y u n i t s s h o u l d b e a d e q u a t e l y p o s i t i o n e d

a n d c l i p p e d t o t h e d r a p e s , w i t h s u f f i c i e n t l e n g t h t o

a l l o w e a s y h a n d l i n g b u t s h o r t e n o u g h t o p r e v e n t

c o n t a m i n a t i o n i f t h e u n i t s a r e d r o p p e d ( F i g . 6 - 1 4 ) .

A v a r i e t y o f i n s t r u m e n t s e t s a r e c o m m e r c i a l l y

a v a i l a b l e . S i n c e t h e p u r p o s e o f t h i s a t l a s i s d e s c r i p t i v e

a n d n o t p r o m o t i o n a l , t h e a u t h o r s ' s p e c i f i c p r e f e r ­

e n c e s a r e n o t l i s t e d ; t h e y wi l l b e s e n t u p o n r e q u e s t .

I t i s i m p o r t a n t t o a c q u i r e q u a l i t y i n s t r u m e n t s , p a r t i c ­

u la r ly for w o r k i n s i d e t h e e a r . A p p a r e n t s a v i n g s f r o m

b u y i n g c h e a p e r b u t p o o r l y m a d e i n s t r u m e n t s c a n b e

i l l u s o r y . I n s t r u m e n t s a r c d e s i g n e d fo r s p e c i f i c p u r ­

p o s e s a n d s h o u l d b e p u r c h a s e d w i t h t h e m i n m i n d .

I n s t r u m e n t s b e a r i n g t h e e n d o r s e m e n t o f a p a r t i c u l a r

s u r g e o n p r o v i d e a s e n s e o f s e c u r i t y a n d s h o u l d b e

c o n s i d e r e d fo r a c q u i s i t i o n ; h o w e v e r , t h e y r e p r e s e n t

t h e p r e f e r e n c e o f t h a t s u r g e o n a n d m a y n o t n e c e s ­

s a r i l y m e e t y o u r n e e d s .

Operating room cards d e s c r i b i n g t h e i n s t r u m e n t s a n d m a t e r i a l s r e q u i r e d fo r d i f f e r e n t s u r g i c a l p r o c e ­

d u r e s s h o u l d b e a v a i l a b l e . T h e y m a k e t h e n u r s e s '

j o b s e a s i e r a n d m o r e e f f e c t i v e . E a r i n s t r u m e n t s p r e f ­

e r a b l y a r e p l a c e d i n a r a c k a n d n u m b e r e d i n t h e

o r d e r i n w h i c h t h e y a r e u s e d — f o r e x a m p l e , N o . 1

s t r a i g h t c a n a l k n i f e . N o . 2 c u r v e d c a n a l k n i f e , N o . 3

d u c k b i l l e l e v a t o r , a n d s o o n . I f t h e s c r u b a n d c i r c u ­

l a t i n g n u r s e s r o t a t e o r t h e o p e r a t i n g r o o m " c o m m i t ­

t e e " b e l i e v e s t h a t n u r s e s c a n b e " j a c k s o f all t r a d e s , "

i t i s u s e f u l t o p r i n t t h e n a m e s o f t h e i n s t r u m e n t s

( b e s i d e the i r n u m b e r s ) a n d t o p l a c e o n t h e t a b l e a

p l a s t i c i z e d , ' s t e r i l i z a b l e " c a r d l i s t i n g t h e n a m e s a n d

p o s i t i o n s o f i n s t r u m e n t s a n d m a t e r i a l s . I n a d d i t i o n ,

c a r d s d e s c r i b i n g t h e p o s i t i o n o f t h e t e a m i n t h e

o p e r a t i n g r o o m s h o u l d b e t a p e d t o t h e w a l l i n a

c l e a r l y v i s i b ' e p l a c e .

Record of Operation

A s i m p o r t a n t a s d e s c r i b i n g w h a t w a s d o n e i s

d e s c r i b i n g w h a t w a s f o u n d , p r e f e r a b l v w i t h a d r a w -

Operating Room'Principles and General Concepts 111

ing. Problem areas should be noted; such records are useful in evaluating prospective causes and factors in both failures and successful results. A stamped or printed drawing or diagram in the operative descrip­tion is useful. Packing techniques are described in specific sections and will not be discussed here. Illustrations of how to apply an oval eye pad (Figs. 6 -15 to 6-17) and a mastoid dressing (Figs. 6-18 to 6-30) are included, as well as two photographs show­ing the application of ointment with a rubber-tipped syringe (Figs. 6 -31 , 6-32) .

FIGURE 6-14. Suction tip and cautery "hanging" in the operating field. They are not left in this position during surgery; this figure simply shows that if clipped correctly, the suction tip and cautery will not become contaminated if they fall.

i

Surgical Time $

It is i m p o r t a n t to develop surgical techniques and habits that fellow a systematic and efficient use of time, but c o m p l e t e n e s s and thoroughness are equally essential. In^ measuring success, results have more weight than speed. Would you prefer to be operated on by a s # g e o n who is rushing to "finish the schedule" of by one who is more concerned about finishing o n l y when his or her purposes of helping you have be;?n surgically achieved?

I

FIGURES 6-15 to 6-17. Placement of an ova] eye pad

Operating Room Principles and General Concepts Operating Room Principles and General Concepts 113

114 Operating Room Principles and General ConceptsOperating Room Principles and General Concepts 115

FIGURE 6-20.FIGURE 6-22.

FIGURE 6-21.FIGURE 6-23.

-------.-----~--

Operating Room Principles and General Concepts 117

118 Operating Room Principles and Genera! Concepts Operating Roojn Principles and General Concepts 119 i

Operating Room Principles and General Concepts

F I G U R E 6 - 3 2 .

CHAPTER 7 Surgical Approaches to the External Ear Canal and Middle Ear

This chapter describes basic general principles underlying the possible alternative approaches to the external ear canal and middle ear. It is obvious that the approach selected will depend upon the type of procedure planned, the needs of exposure, and the surgeon's preference or ability. Specific approaches are described in the chapters in Section IV; however, since these basic principles apply partly or totally in those approaches, they are described separately here in order to avoid repetition.

Three alternative approaches are available to gain access to the external ear canal and middle ear: the transcanal, the endaural, and the postauricular (Fig. 7 - 1 ) . In all three approaches, all surgical steps are equally important and should be done methodically and carefully, from preparing the patient, draping, and positioning, to applying the last piece of tape to the dressing. Meticulous care should be observed. The procedure is not finished when the flaps are repositioned; it is finished when the ear is healed. All steps, including postoperative care, are essential for proper healing.

Transcanal Approach

Highlights

1. Adequate visualization.

2. Completion of incisions (all the way through).

3. Elevation of an intact flap. 4. Entrance into the middle ear beneath the an-

nulus.

5. Meticulous anatomic repositioning of the flap. 6. Careful packing.

Pitfalls

1. Operating in a small space without visualiza­tion.

2. Tearing the flap or tympanic membrane. 3. Suctioning the flap. 4. Making superficial incisions. 5. Entering the middle ear above the annulus. 6. Selecting an inadequate approach.

Inspection and Cleansing

Once the patient has been adequately positioned and the ear has been sterilely prepared and draped, the canal and tympanic membrane are inspected with an ear speculum. An oval, anteriorly beveled, non-reflecting speculum of the largest possible size is used. Too small a speculum provides inadequate vision and is too loose; too large a speculum causes folds in the ear canal that obstruct vision and macer­ate the skin. The correct size allows satisfactory vision and sufficient tightness to allow bimanual explora­tion.

Surgical Approaches to the External Ear Canal and Middle Ear Surgical Approaches to the External Ear Canal and Middle Ear 123

The narrowest portion of the external ear canal is medial to the junction of the bony and cartilaginous canal; it is at this point that placement of the spec­ulum is critical. The canal is carefully cleansed with ring curets, suction (No. 5), or both. The skin and tympanic membrane are carefully visualized, and the size of the canal is appreciated. This visualization is very important, since the surgeon should first think in terms of anatomy. Whatever needs to be done in the middle ear is done best with adequate exposure. Again, positioning of the patient and the surgeon plus adequate angulation of the arm of the micro­scope are essential. It is a good idea to gently irrigate the canal (with either saline or alcohol).

Injection of Local Anesthetic

Injection of the anesthetic is a skill to be mastered by all means. It is a crucial step that decides if the procedure will be done in a clean, dry field or in a field obstructed by blood and offering inadequate vision. A local anesthetic with vasoconstrictor is used, usually lidocaine 2% with 1:100,000 epineph­rine. Alternative anesthetic agents (owing to aller­gies, desire for a longer-lasting effect, or other rea­sons) or different concentrations of epinephrine are acceptable, but maximum doses must be kept in mind in order to avoid toxicity or cardiovascular effects, or both. A syringe affording ease of injection (for example, Carpule) is preferred. A 27- or 30-gauge needle is used. A nasal speculum is used for initial injections into the four quadrants of the carti­laginous canal (Fig. 7-2A) . The bevel of the needle is placed parallel to the surface of the underlying cartilage (or bone), and injection is done very slowly in order to avoid blebs. (If a small bleb is formed, it can be punctured with a needle.) With slow injection under direct vision infiltration and blanching of the skin can be clearly noted; thus the necessary amount of anesthetic can be easily decided. With the aid of an ear speculum, additional injections are done, if needed, into the bony canal under direct vision until blanching of the skin is observed. The skin of the osseous canal is thinner than that of the cartilaginous portion; it is usually simpler and safer to inject into the cartilaginous portion, allowing the injected so­lution to "dissect its way toward the annulus." On occasion, under local anesthesia a facial paralysis becomes evident at this point. This denotes a dehis­cent facial nerve, which should completely recover.

Incisions

With the speculum tightly in the canal and the surgeon working with two hands, the incisions are made. A Paparella No. 1 straight canal knife or sickle knife is used for the first incision at 12 o'clock in a direction straight toward the surgeon (Fig. 7-2B) . A second incision is made at 6 o'clock, curving toward the vertical incision; this curved incision can be made with a curved canal knife. The length of the flap (distally from the annulus to the horizontal incision) may vary, as well as the location of the vertical incision. In a routine stapedectomy a 6-mm flap should suffice, whereas in a more extensive explo­ration with a small atticotomy, or if extensive bony canal is to be removed, an 8-mm flap might be necessary. If the canal is wide, a large flap extending even to the cartilaginous canal can be used, since folding it anteriorly will not obscure vision or result in a tight space with no room to work. The length of the flap is then determined by means of exposure and size of the canal.

If attic disease or fixation of the head of the malleus is suspected, a wider flap is elevated, and the vertical incision is made at the 1 or 3 o'clock position in order to provide a flap of sufficient size to cover the defect easily. If more extensive surgery is anticipated, an endaural incision is used. When making the incision, the underlying bone should be "felt" with an instru­ment, even to the point of producing a sound, to make certain that the skin is completely sectioned. The junction of the skin with the annulus, at 12 or 3 o'clock, is usually thicker and richer in connective tissue. Complete sectioning of this area is very im­portant; a Bellucci scissors is very helpful for this purpose. No attempt to lift flaps or gain entrance into the middle ear should be made until the incisions are completed and the skin flaps are free.

Elevation of Flaps

With the skin edges free, the surgeon takes his or her finger off the hole of the suction tube and holds the speculum and suction in the left hand (for a right-handed surgeon) (Fig. 7 -2C) . This helpful tech­nique is not difficult to master, and with an ade­quately shed speculum obviates the need for a spec­ulum holder. The latter is a useful instrument, the most widely used design being the classic Shea

FIGURE 7-2.

Surgical Approaches to the External Ear Canal and Middle Ear 125

speculum holder; other designs are modifications incorporating surgeons' various preferences.

With the use of a flat elevator, preferably a duckbill or large curved canal knife, the skin is gently sepa­rated from the underlying bone (Fig. 7-2D). Special care must be observed when a prominent tympano­mastoid suture is present; simply lifting the skin will cause tears in the flap. A smaller sharp instrument (for example, a No. 1 straight knife or sickle knife) is helpful in releasing connective tissue attachments. Separation must be slow and careful in order to preserve the flap intact. The suction tip (finger off the hole) is used behind (posterior to) the elevator. The skin is elevated evenly, avoiding tunneling, and the flap is elevated until it reaches the annulus. At this point, greater magnification may be used (for example, 16 x) in the microscope. All bleeding must be controlled, and entrance to the middle ear should be "dry." A No. 20 suction tip is preferred for the middle ear. Small sources of bleeding can be stopped using "Adrenalin tape." Occasionally cautery is needed; however, it is preferable to avoid any edema or necrosis, such as that caused by cauterization, in these thin flaps.

The middle ear is entered beneath the annulus with a duckbill or curved canal knife (Fig. 7 -2E) . If there is adequate visualization, the site of entrance is not crucial; in general, however, it is preferable to enter interiorly toward the round window rather than toward the ossicles. Once the annulus is separated, a drumhead elevator is introduced and the annulus is gently lifted by a sweeping motion from 6 to 12 o'clock through the whole extent of the exposed annulus. The chorda tympani should be gently and carefully moved out of the field of vision; if this would stretch it, the best course is simply to cut it with a Bellucci scissors (Fig. 7-3A, B). In cases in which adhesions or thickened mucoperiosteum ob­scure visualization of the middle ear structure, it is imperative to enter the middle ear cautiously and systematically. Avoiding damage, particularly to os­sicles (or their remnants) or an exposed facial nerve, is crucial. The cavity is entered inferiorly, where the round window niche area is found; from there the surgeon works toward the ossicles. If they are still obscured, or if the anatomy is (or seems) distorted, a small atticotomy is done. The head of the malleus and body of the incus (which usually are present even if extensive ossicular erosion has occurred) are identified, and the dissection is started from this point. (Beware of the tensor tympani area, where the facia] nerve might be dehiscent.) The chorda tympani can also serve as a guide to follow. Whatever the choice, thickened tissue should not be removed blindly.

Exposure of the Middle Ear

The middle ear is visualized and the mucosa as well as the different anatomic structures are identi­fied before any planned procedure is begun (Fig. 7-3C). Methodical evaluation of the cavity is good practice. This includes evaluation of ossicular mobil­ity, which is done by mobilizing the long process of the malleus with a drumhead elevator or joint knife (Fig. 7 -3D) , followed by palpation of the incus and stapes (Fig. 7 -3E) . Testing the mobility of the stapes includes the footplate, not the head alone. If more complete exposure of the oval window is needed, the posterior canal wall should be curetted. The tip of the curet should always be in view. A sharp curet that is as large as possible should be utilized. An angled curet is used to remove the bone of the posterior canal, including the area of the scutum. In general, it is better to curet from 12 to 6 o'clock in order to avoid accidental dislocation of ossicles. The curet should not be used in a perpendicular fashion. Special time should be dedicated to completely re­moving bone fragments, which if left in the middle ear stimulate localized tissue reaction and make the cavity prone to infection. Again, for good visualiza­tion it is important to position the patient appropri­ately, with the surgeon and microscope in the correct position as well.

Closure

Upon completion of middle ear work (procedures are described in specific chapters), the flaps are repositioned. At the same time, they are carefully cleansed, fraed of debris with thin suction tips, a joint knife, or both, and examined for tears. The tympanic membrane also is examined for small punc­tures or lacerations; if any are present, their edges are closely approximated, and small pieces of Gel-foam are used to cover them. The paramount consid­eration, requiring great care, is anatomic position. The fact that flaps shrink initially must be taken into account.

Revisions

Ideally, previous reports should be available. Re­visions shoi'ld be approached as a "box of surprises" from beginning to end. The main points to keep in

Surgical Approaches to the External Ear Canal and Middle Ear

FIGURE 7-3.

Surgical Approaches to the External Ear Canal and Middle Ear 127

mind are that flaps are quite thin and tear easily, and that bony defects of the ear canal are to be expected. Careful incisions and elevation are used. Adhesions are common and should be sectioned carefully and sharply in order to avoid tears. Repo­sitioning of the flaps should be carefully done and anatomically adequate; adequate packing is of the utmost importance as well.

Packing

Alternatives to packing exist, depending upon the particular case and the surgeon's preference. They are all satisfactory and will work if done correctly. Different materials can be utilized; if used properly, most of them suffice. Excessive pressure must be avoided. Antibiotic or steroid ointments or solutions, or both, are useful in preventing localized inflam­mation and infection. Only the most common pack­ing techniques will be mentioned.

1. A basket is fashioned from surgical rayon or Owen's silk strips moistened with antibiotic or ste­roid ointment. Cotton soaked in antibiotic solution fills the space, and the silk is used as a rosebud packing. A 1/2-in gauze pack with antibiotic ointment is placed in the lateral third of the canal (Fig. 7 - 4 A -C). This type of packing provides adequate pressure to keep the flaps flat, but not enough to damage them. It should be removed at intervals of one week for the gauze and two weeks for the rosebud; if left for a longer period granulation tissue invades the silk, making it difficult if not impossible to remove it by simply pulling.

2. The canal is filled with Gelfoam soaked in antibiotic solution. It is placed initially in layers, with Gelfoam strips covering all areas of incision. The lateral aspect of the canal can be filled with ointment, or a piece of sterile cotton can be placed (Fig. 7-4D) . The disadvantage of this method is that it takes a long time for the Gelfoam to come out spontaneously; thus removal must be done very carefully in order to avoid flap disruption. Gelfoam promotes granu­lation. This type of packing may require the use of otic drops or ointments.

3. The canal is filled with an antibiotic ointment as the sole packing, and a piece of cotton is placed in the meatus (Fig. 7 -4E) . This method of packing requires perfect approximation of intact flaps.

4. The incisions are completely covered with com­pressed, dry Gelfoam in strips, and a flat, round piece of Gelfoam is placed over the tympanic mem­brane. Ointment is then inserted into the canal through a syringe with an 18-gauge needle (Fig. 7-

4F) . Gelfoam provides some stimulation for granu­lation, favors healing, and discourages maceration of the skin flaps.

Canalplasty in Exploratory Tympanotomy

If the canal is small or "tight" owing to thick skin or anterior "bony overhang that prevents satisfactory visualization despite adequate approach and posi­tioning, a canalplasty becomes a very useful proce­dure (Fig. 7 - 5 ) .

Highlights

1. Before performing a canalplasty: A. Ensure that the approach is the best one. B. Ensure that the positioning of the patient and

surgeon is adequate. 2. Use curets as needed.

3. Protect the anterior window shade flap. 4. Drill the anterior wall carefully. 5. Carefully remove all debris.

Pitfalls

1. Drilling the skin flaps. 2. Exposing the temporomandibular joint capsule

anteriorly. 3. Inadequately removing bone dust and debris,

which leads to inflammation and infection.

Procedure

An anesthetic and vasoconstrictors are injected into the anterior wall. The purpose is to expose the bony canal and safely remove as much bone as needed for adequate exposure. This can be accom­plished with an "anterior window shade" with a horizontal component and two vertical limbs; the vertical limbs preferably should not involve the vas­cular strip. The horizontal incision can be made medially or laterally—that is, immediately above the annulus or at the bony cartilaginous junction. In the medial horizontal incision, the skin is gently elevated laterally as a flap with a duckbill elevator or curved

Surgical Approaches to the External Ear Canal and Middle Ear

FIGURE 7-4.

Surgical Approaches to the External Ear Canal and Middle Ear

F I G U R E 7-5.

130 Surgical Approaches to the External Ear Canal and Middle Ear

canal knife, and gently rolled anteriorly (Fig. 7 - 5 A ,

B,). This skin is very thin and tears easily; thus lifting must be done carefully. In the lateral horizontal incision, a flap is developed inferiorly until it reaches the annulus (Fig. 7 - 5 C , D). Before drilling, the sur­geon must ensure that the flaps are safely flattened in order to avoid drilling them. It is a good idea to cover them with a strip of Owen's silk for added protection; if the flaps are touched by the drill bit, the silk will be trapped. A drill bit large enough to be safe but small enough to leave room for drilling should be used; it can be supplemented with curets as needed. Proper use of curets should be learned; they are safe and very effective.

Enough bone should be removed to permit visu­alization of the anterior annulus. Care must be taken to avoid entering the temporomandibular joint an­teriorly. If the temporomandibular joint is entered despite these precautions, a small defect may be created that is extracapsular; if this is the case, no particular coverage is needed except for the flap. In obtaining satisfactory visualization of the entire an­nulus, it should be remembered that adequate posi­tioning of the patient's head, and of the surgeon, will avoid unnecessary drilling. Exposure of posterior mastoid cells is not a major problem; they should be adequately covered with the skin flap. Once the entire bone work has been done, time should be allotted for complete removal of bone fragments in order to prevent local tissue reaction and possible infection. The flaps are completely elevated poste­riorly; the anterior flap ("window shade") is anatom­ically repositioned and all bleeding vessels are con­trolled (Fig. 7 - 5 E ) . Then, and only then, can the middle ear be entered.

Endaural Approach

Highlights

1. Same as with the transcanal approach.

2. Control bleeding before entering the middle ear.

3. Position the two-prong retractors properly and carefully.

Pitfalls

1. Same as with the transcanal approach. 2. Exposing or damaging the helix with a Lempert

11 incision.

3. Inadequately packing and positioning the flap i,

resulting in adhesions or stenosis.

The endaural approach can be used for an explor­atory tympanotomy, a tympanoplasty, and a masto­idectomy, and is particularly useful and safe (or revision surgery. It is useful, as well, for "tigr^" canals and canals with thick skin. This approaca utilizes different sizes of incisions according to neec , varying from a minimal to a large Lempert II incision (described below). It is insufficient for large mastoid cavities and does not provide a good view of the anterior annulus unless a canalplasty is done.

Position, inspection, and cleansing are done as i i transcanal procedures. Injection of local anesthefcc with vasoconstrictors is similar as well, except thct additional injections are made between the tragus and helix (at the incisura) and immediately antericr to the helix (Fig. 7 - 6 A ) . The endaural approac l avoids the use of an ear speculum and provides a direct view of the middle ear.

Incisions

For purposes of exposure, it is best to use a curved nasal speculum. Incisions are made with a scalp-'l. The first incision (Lempert I) is made semicircumfer-entially between 6 and 12 o'clock on the poster or wall at the bony cartilaginous junction (Fig. 7 - 6 >')•

This incision must extend down to the bone. T >.e

second incision (Lempert 11) runs between the trag JS and helix and incisura; care must be taken not 'O expose or cut the helix. The extension of this incisi >n depends upon the degree of exposure needed, vary­ing from a few millimeters (for an exploratory tym­panotomy) to a full 3 . 4 cm (for a mastoidectom 1 ). This incision is made in the ear. Caution must ie exercised not to deepen it immediately after going through the subcutaneous tissue, since branches' :>f the superficial temporal artery and vein are prese it in this area; too deep a cut also may section t ' i e

temporal fascia, which might be needed for grafting purposes. It is important to completely section the connective tissue and to expose the bony canal at t! ie

level of the incisura, allowing more space. Snv 11 bleeding vessels are cauterized. The remaining pos­terior canal skin (cartilaginous portion) is preserved and gently elevated with a small periosteal e l e v a t e , leaving the whole posterior bony canal clearly e ;-

posed (Fig. 7 - 6 C ) . On occasion, a small free sk'n graft can be taken safely from this area. Two tw..-prong retractors are used for exposure. It is useful o position them at right angles to each other, one

Surgical Approaches to the External Ear Canal and Middle Ear 131

FIGURE 7 - 6 .

130 Surgical Approaches to the External Ear Canal and Middle Ear

canal knife, and gently rolled anteriorly (Fig. 7 - 5 / 4 ,

B,). This skin is very thin and tears easily; thus lifting must be done carefully. In the lateral horizontal incision, a flap is developed inferiorly until it reaches the annulus (Fig. 7 - 5 C , D). Before drilling, the sur­geon must ensure that the flaps are safely flattened in order to avoid drilling them. It is a good idea to cover them with a strip of Owen's silk for added protection; if the flaps are touched by the drill bit, the silk will be trapped. A drill bit large enough to be safe but small enough to leave room for drilling should be used; it can be supplemented with curets as needed. Proper use of curets should be learned; they are safe and very effective.

Enough bone should be removed to permit visu­alization of the anterior annulus. Care must be taken to avoid entering the temporomandibular joint an­teriorly. If the temporomandibular joint is entered despite these precautions, a small defect may be created that is extracapsular; if this is the case, no particular coverage is needed except for the flap. In obtaining satisfactory visualization of the entire an­nulus, it should be remembered that adequate posi­tioning of the patient's head, and of the surgeon, will avoid unnecessary drilling. Exposure of posterior mastoid cells is not a major problem; they should be adequately covered with the skin flap. Once the entire bone work has been done, time should be allotted for complete removal of bone fragments in order to prevent local tissue reaction and possible infection. The flaps are completely elevated poste­riorly; the anterior flap ("window shade") is anatom­ically repositioned and all bleeding vessels are con­trolled (Fig. 7 - 5 E ) . Then, and only then, can the middle ear be entered.

Endaural Approach

Highlights

1. Same as with the transcanal approach.

2. Control bleeding before entering the middle ear.

3. Position the two-prong retractors properly and carefully.

Pitfalls

1. Same as with the transcanal approach.

2. Exposing or damaging the helix with a Lempert II incision.

3. Inadequately packing and positioning the flap i, resulting in adhesions or stenosis.

The endaural approach can be used for an explor­atory tympanotomy, a tympanoplasty, and a masto­idectomy, and is particularly useful and safe tor revision surgery. It is useful, as well, for "tigHj?" canals and canals with thick skin. This approaca utilizes different sizes of incisions according to neec , varying from a minimal to a large Lempert II incision (described below). It is insufficient for large mastoid cavities and does not provide a good view of the anterior annulus unless a canalplasty is done.

Position, inspection, and cleansing are done as :i transcanal procedures. Injection of local anesthetic with vasoconstrictors is similar as well, except thct additional injections are made between the tragus and helix (at the incisura) and immediately antericr to the helix (Fig. . 7 - 6 / 4 ) . The endaural approac 1 avoids the use of an ear speculum and provides a direct view of the middle ear.

Incisions

For purposes of exposure, it is best to use a curved nasal speculum. Incisions are made with a scalp.'l. The first incision (Lempert 1) is made semicircumfor-entially between 6 and 12 o'clock on the poster or wall at the bony cartilaginous junction (Fig. 7 - 6 i). This incision must extend down to the bone. T le second incision (Lempert 11) runs between the trag js and helix and incisura; care must be taken not ro expose or cut the helix. The extension of this incisi >n depends upon the degree of exposure needed, vary­ing from a few millimeters (for an exploratory tym­panotomy) to a full 3 / 4 cm (for a mastoidectonv ). This incision is made in the ear. Caution must te exercised not to deepen it immediately after going through the subcutaneous tissue, since branches'of the superficial temporal artery and vein are presc it in this area; too deep a cut also may section t'ie temporal fascia, which might be needed for grafting purposes. It is important to completely section the connective tissue and to expose the bony canal at tlie level of the incisura, allowing more space. Srmll bleeding vessels are cauterized. The remaining pos­terior canal skin (cartilaginous portion) is preserved and gently elevated with a small periosteal e l e v a t e , leaving the whole posterior bony canal clearly e:-posed (Fig. 7 - 6 C ) . On occasion, a small free skm graft can be taken safely from this area. Two twu-prong retractors are used for exposure. It is useful o position them at right angles to each other, one

Surgical Approaches to the External Ear Canal and Middle Ear

FIGURE 7 - 6 .

132 Surgical Approaches to the External Ear Canal and Middle Ear

pointing cephalad (superiorly) and the other caudad (posteriorly); this provides better exposure and sta­bility and is less inconvenient for the surgeon. Tem­poral fascia is harvested at this point (discussed in Chapter 12) and all bleeding vessels are controlled. With the scalpel, incisions can be made at 6 and 1 or 2 o'clock (Fig. 7 -6D) . These incisions allow for easier development of the flap; however, the flap can be elevated without the incisions. The flap is elevated in the same manner as in a transcanal incision. The same principles and technique also apply for a can­alplasty.

Closure

The flap is repositioned anatomically; particular attention is paid to repositioning the skin, which must cover the cartilaginous canal. Subcutaneous tissues are approximated with interrupted absorbable sutures (for example, 3 - 0 chromic catgut). Approxi­mation does not need to be very tight at the incisura. Skin is approximated with absorbable 4 - 0 silk or nylon sutures. The first skin suture should be at the incisura; as in other ear incisions, there is remarkably good healing in this area. Packing is done as in transcanal procedures for the bony canal; however, it is best to use 1/2-in gauze impregnated with anti­biotic or steroid ointment in the lateral third (carti­laginous canal), followed by a mastoid dressing. The gauze and the skin sutures are removed one week after the procedure. At this time the authors usually fill the space with antibiotic ointment for one addi­tional week.

Postauricular Approach

Highlights

1. Same as for transcanal and endaural ap­proaches.

2. The postauricular incision should be made plane by plane.

3. The canal should be reached in the "avascular" plane.

4. Cleansing of all debris should be done carefully.

Pitfalls

1. Tearing of the canal with the three-prong re­tractors.

2. Inadequately cleansing debris, learing to wound infection.

The postauricular approach can be used for an exploratory tympanotomy, a tympanoplasty, and a mastoidectomy. It provides a good view of he an­terior rim of the annulus, unless there is a prr^ ninent bony overhang or a "tight" canal; h o w e v ^ iti is useful for dealing with these two problems as we I.

Position, inspection, and cleansing are done in transcanal and endaural procedures; however, pa­tient preparation and shaving of hair is different (see Chapter 6) . Injection of a local anesthetic is similar to the transcanal procedure, as far as the a n a l is concerned; however, a postauricular injection s nec­essary in the whole area where the incision i< to be made, as well as in the posterior aspect of the canal from behind. It is useful to lift the auricle, 7ull it forward, and inject posteriorly, while feeling the tip of the needle and the flow of anesthetic and vaso­constrictors with the index finger placed in th* mea­tus of the canal; this maneuver ensures arVquate injection.

Incisions

The classic incision is made 3/4 cm behind the posterior sulcus, with the inferior end dev ating posteriorly. In children, the incision is higr and posterior with the inferior limb far posterioi since the facial nerve can be very superficial in its exit at the stylomastoid foramen (because of lack of devel­opment of the mastoid tip). For cosmetic pu poses the incision can be made in the crease itself, I ut the cosmetic advantage is relative; this location lends itself to minor healing problems, small epic ermal cysts, and so on. An additional incision that an be made is the posterosuperior (Portmann), whu h is a compromise between the posterior incision at d the anterosuperior (Hermann) incision. (In spite of its good exposure, the latter is not used because -i may lead to necrosis of the helix.) The posterosu ?erior incision provides excellent exposure.

Procedure

The Incision is made with a scalpel and deepened perpendicularly through subcutaneous tissues with­out advancing too far. The purpose is to read i the musculo-aponeurotic or "avascular" plane. C a i t e r " can be used for bleeding vessels. If the planet ar<'

Surgical Approaches to the External Ear Canal and Middle Ear 133

developed carefully, large branches of the posterior auricular artery usually will not be sectioned; if this does occur, it is best to tie them with a nonabsorbable suture. Many surgeons use cutting cautery in the skin, which is effective in terms of surgical time and dryness of the field. However, this must be weighed against the disadvantage of skin healing secondary to a cutting cautery burn.

If the right plane is reached, the auricle is pulled anteriorly (forward) and the cartilaginous canal is identified, as well as the spine of Henle. (At this point the temporal fascia can be harvested; this is discussed in Chapter 12.) Once this is done, the connective tissue plane behind the cartilaginous canal can be developed sharply and safely. All bleeding vessels, if there are any, should be controlled. Ele­vating the plane toward the zygomatic root gains room to mobilize the auricle forward (anteriorly) easily (Fig. 7 -7A) . A circumferential incision is made at the bony cartilaginous junction posteriorly, as in

' the endaural procedure. (We are discussing explor­atory approaches alone; other types of flaps for other purposes—for example, Korner's—will be dealt with later.) A piece of twill tape passed gently through the incision ensures that the skin of the meatus posteriorly is not torn when using a retractor, and at the same time serves to keep this flap out of the field of vision (Fig. 7 - 7 B ) . With the use of a three-prong Wullstein retractor, the auricle (pinna) is gently pulled anteriorly with the posterior cartilaginous canal, protected by the twill tape (Fig. 7 -7C) . Care must be taken not to tear this skin and cartilage. If a Wullstein retractor is not large enough, a modified Schuknecht three-prong retractor is used. (This is usually necessary in a mastoidectomy but uncommon in exploratory procedures.)

From this point on, the same procedure is followed as in endaural or transcanal incisions. Closure is preceded by careful removal of debris. The packing of the bony canal is similar to that in other ap­proaches; the lateral aspect of the canal (cartilagi­nous) is packed as in the endaural approach. Post­auricular closure is done with interrupted absorbable sutures for subcutaneous tissues (for example, 3-0 chromic catgut). This layer should be approximated carefully; otherwise, the pinna may lack adequate subcutaneous support and show a tendency to proj­ect anteriorly. Skin is approximated with interrupted, nonabsorbable silk or nylon. Some surgeons close the skin with 4-0 catgut sutures; although this method may be adequate, the authors do not use it. A mastoid dressing is applied. Removal of sutures and packing is done as in the endaural approach.

Simple Mastoidectomy as a Surgical Approach

A simple mastoidectomy is described here as a general surgical approach for different procedures; it is discussed as a specific procedure in Chapter 5. Mastoid procedures for chronic otitis are described separately in Chapter 10.

Aim

Exenteration (removal) of all mastoid air cells while

maintaining the integrity of the posterior canal.

Highlights

1. Skin incision is performed with the scalpel perpendicular to the skin.

2. Incision should be deepened in layers. 3. Careful elevation of intact periosteum should

be done. 4. Retractors must be adequately positioned. 5. Complete exposure of landmarks is important. 6. Carefully close in layers.

Pitfalls

1. Tearing of the skin of the posterior ear canal.

2. Inadequate exposure. 3. Injuring a high sigmoid sinus. 4. Injuring the facial nerve by going:

A. Deep to the horizontal semicircular canal. B. Too far anterior in the digastric ridge.

5. Dislocating the incus by drilling blindly into the antrum area.

6. Exposing the dura mater. 7. Drilling the semicircular canals.

Positioning, patient preparation and draping, and injection have already been discussed. As described in previous chapters, a classic postauricular incision will be used, starting at the level of the linea tem­poralis and following the contour of the external meatus to turn posteroinferiorly at the level of the mastoid tip.

FIGURE 7-7.

Surgical Approaches to the External Ear Canal and Middle Ear 135

Incision and Exposure

Before initiating postauricular work, it is a good

idea to place a piece of sterile cotton in the canal in

order to avoid accumulation of debris and bone dust.

The incision is made in layers with a scalpel held

perpendicularly to the skin. Subcutaneous vessels

are cauterized. A plane between the musculo-apo-

neurotic layer and connective tissue is reached by

sharp dissection, and developed. It is possible in this

plane to avoid damaging branches of the posterior

auricular artery; if damage does occur, it is better to

ligate than to cauterize them.

The periosteum is identified and sectioned, follow­

ing the contour of the external ear canal. Vertical

incisions at 45-degree angles are made at 6 and 12

o'clock (toward the linea temporalis and toward the

mastoid tip) (Fig. 7-SA). The intact periosteum is

elevated carefully, using periosteal elevators. This is

important for closure, since re-establishing the peri­

osteum in position will avoid a marked postauricular

depression. As soon as the periosteum is elevated,

the landmarks become apparent. It is useful to expose

the root of the zygoma; this provides better mobility

when positioning the retractors. Two three-prong

retractors are positioned at right angles to one an­

other (Fig. 7 -8C) .

Specific surgical steps are described in Chapter 5

(pages 45 -47) . The discussion here will focus on

closure and treatment of intraoperative complica­

tions.

Closure

Careful washing and thorough removal of all de­

bris and bone dust are of the utmost importance in

order to prevent postoperative inflammation and

infection. The retractors are removed, and the peri­

osteal flap is repositioned and secured to the poste­

rior canal by nonabsorbable sutures, (f the flap is

intact and the approximation is adequate, marked

postauricular depression will be avoided. Subcuta­

neous tissues are approximated with layers of inter­

rupted absorbable sutures (for example, 3-0 or 2-0

chromic catgut), and skin with interrupted nonab­

sorbable sutures (for example, 4-0 silk or nylon),

making sure that the skin and subcutaneous sutures

do not overlap. A mastoid dressing is then applied.

Intraoperative Complications

or Problems

1. Facial nerve trauma.

2. Exposure of the dura mater.

3. Drilling of the semicircular canals.

4. Damage to the sigmoid sinus.

5. Dislocation of the incus.

Facial Nerve Trauma. Inadvertent exposure of the facial nerve sheath does not necessarily imply injury

to the nerve and requires no treatment. However, if

the nerve itself is injured in its course through the

fallopian canal, it should be opened for several mil­

limeters to ensure continuity. The nerve sheath should not be opened unless discontinuity of nerve fibers is

suspected. Opening of the sheath might allow in­

growth of fibrous tissue, which can compromise

nerve regeneration, if discontinuity of fibers exists,

they should be apposed cleanly to each other. If the

injury is severe and includes maceration, the nerve

should be sharply and cleanly incised and an end-

to-end anastomosis performed (see Chapter 18). If

the traumatized segment is too broad, nerve grafting

should be done. Exposed nerve fibers should be

covered in order to avoid ingrowth of fibrous tissue.

They should not be covered with fascia, since fascia provides such ingrowth; materials that discourage

fibrous tissbe ingrowth (for example, thin sheets of

gold foil) should be used.

Facial paralysis that is evident immediately post­

operatively may be caused by intraoperative injury,

the effect of local anesthesia, or pressure from pack­

ing on a dehiscent nerve. Paralysis from such sources

necessitates immediate re-exploration unless the sur­

geon is certain there is no facial nerve damage, in

which case packing and pressure should be released.

Steroids can be argued against, but in this case the

authors believe their use may be beneficial. Delayed

facial paralysis (developing after the patient has re­

covered without paralysis) requires loosening of the

packing and should be treated as Bell's palsy.

Exposure of the Dura Mater. Exposure of the dura

mater during mastoidectomy can happen at the teg­

men (middle cranial fossa dura) and at the posterior

cranial fossa dura. Without penetration or rupture of

the dura itself, it is of no significance except as a

reflection of poor technique. If the dura is torn a

cerebrospinal fluid leak will result, with subsequent

potential for infection. Small leaks in the middle

cranial fossa often cease spontaneously because of

the abundant arachnoid that is present. A small piece

FIGURE 7-8.

Surgical Approaches to the External Ear Canal and Middle Ear 137

of fascia can be used for coverage, after it is ascer­

tained that the surrounding dura is intact. (Remove

a few millimeters in each direction.) The fascia can

be tucked in place. Larger defects can be closed by

using cartilage or bone lateral to the fascia, or both.

Intraoperative and postoperative antibiotics are used

as in all other complications involving areas or struc­

tures beyond the confines of the mastoid or middle

ear cavity. Antibiotics that cross the blood-brain

barrier should be used; this is an important but

frequently overlooked point.

Posterior cranial fossa dura has less arachnoid,

and leaks there are occasionally quite profuse. As

soon as the leak occurs, a large piece of Gelfoam or

twill tape is placed over the defect and finger pres­

sure is applied. This is followed by tissue grafting

with temporal muscle medially and fascia laterally.

The cavity is then covered with large pieces of

Gelfoam, and, if necessary, filled under pressure. If

the flow continues, an indwelling lumbar catheter

rhay. be placed in order to diminish the cerebrospinal

fluid pressure for several days.

Drilling of the Semicircular Canals. Damage occurs

most commonly at the dome of the lateral (horizontal)

semicircular canal and occasionally at the posterior

semicircular canal when exposing Trautmann's tri­

angle. If the damage is recognized before injury to

the membranous labyrinth occurs, sealing the fistula

with Gelfoam or tissue graft may prevent serious

sequelae. Damage to the membranous labyrinth re­

sults in an irreversible disturbance in hearing and

balance, except on rare occasions in which previous

involvement of the labyrinth has allowed its com-

partmentalization.

Damage to the Sigmoul Sinus. The best way to deal

with this problem, as with all other complications, is

to avoid it. This can be achieved bv having a good

set of preoperative mastoid films that provide infor­

mation on the location of the sigmoid sinus (for

example, "high-lateral," "low-medial," "anterior,"

etc.) , and by developing the mastoidectomy step by

step. Ear surgery is not for "racing surgeons."

Laceration of the sigmoid sinus results in profuse

hemorrhage. A similar problem can occur with a

dehiscent jugular bulb in the hypotympanum. Bleed­

ing can often be stopped by immediate, firm, appli­

cation of large pieces of Gelfoam and twill tape and

by finger pressure, followed by application of oxi­

dized cellulose (oxycel). This in turn is covered by

pieces of Gelfoam and fascia if needed. At the end

of the procedure, extradural hematoma should be

ruled out.

Dislocation of the Incus. This complication entails

exploratory tympanotomy and repositioning of the

incus in its normal anatomic position (see Chapter

11).

Posterior Tympanotomy (Facial Recess) as a Surgical Approach

The posterior tympanotomy (facial recess) proce­

dure is included here as a general surgical approach

for different purposes; aim, highlights, pitfalls, and

procedure are described in Chapter 5. Specific indi­

cations are discussed in pertinent preceding chapters.

Closure is exactly the same as in a simple masto­

idectomy. Management of complications also is iden­

tical except for those inherent in this specific ap­

proach.

Intraoperative Complications or Problems Inherent in This Approach

1. Damage to the tympanic membrane.

2. Perforation of the bony external ear canal.

Damage» to the tympanic membrane implies a

transcanal exploration. The borders of a small tear

are cleansed and approximated anatomically and

covered with Gelfoam. A larger defect necessitates a

graft (to be discussed in Chapter 12).

Small perforations of the posterior wall of the

bony external ear canal are not significant and need

no repair except for adequate coverage with skin

flap. Major defects may require posterior wall recon­

struction.

Mastoidotomy as a Surgical Approach

Aim

Visualizing the antrum and establishing (or re­

establishing) communication between the mastoid

and middle ear cavities.

The highlights, pitfalls, technique, and complica­

tions of a mastoidotomy are essentially those of a

cortical mastoidectomy (see Chapter 5), but the

amount of bone removed is much less. This proce-

138 Surgical Approaches to the External Ear Canal and Middle Ear

dure is performed using a postauricular or endaural approach. Drilling is done in the fossa mastoidea toward the antrum. Whether the purpose is to re­move tissue blockage, improve aeration to the middle ear, or introduce an electrode into the middle ear, the opening should be large enough to allow visu­alization of the antrum.

Meatoplasty

Meatoplasty is discussed in this chapter as a gen­eral concept owing to its practical and often crucial importance in otologic procedures. The meatus con­sists of skin, subcutaneous tissue, cartilage, and underlying bone. It is essential to consider all of these structures in a meatoplasty; adequate treatment of the soft tissues combined with insufficient atten­tion to the underlying cartilage or bony meatus, or both, might result in an inadequate meatoplasty. Meatoplasty is essential for obtaining a good surgical result in tympanomastoid surgery and in tympano­plasty (when indicated and usually associated with canalplasty).

Large canals do not need a meatoplasty. The procedure is used for small canal entrances (open­ings), whether congenital or acquired (by disease or by surgery). A normal-sized meatus allows for proper aeration and self-cleansing of the canal, and adequate sound conduction. The procedures described here (exemplified for practical purposes in open- and closed-cavity tympano-mastoidectomy) apply in principle to other surgical cases as well.

With the understanding that a postauricular and an endaural approach can be used interchangeably, a postauricular approach is described in the meato­plasty for an open-cavity tympano-mastoidectomy, and an endaural approach for a closed-cavity tym­pano-mastoidectomy. The development of a Korner's flap will be described in the former, as well.

Aim

To provide a well-epithelialized meatus that is wide enough to aerate the ear canal and allow proper sound conduction and self-cleansing.

Highlights

1. Maintain continuity and integrity of the skin

flap.

2. Effect meticulous hemostasis. 3. Thin the skin flap. 4. Excise conchal cartilage (the cornerstone of

meatoplasty). 5. Drill underlying bone (if necessary). 6. Use sutures to keep the meatus open. > 7. Cover all open areas. 1

8. Postoperative care must be adequate and s e ­quent.

Pitfalls and Complications

t. Leaving skin flap with a thin base. 2. Tearing of skin flap.

3. Excessive bleeding. 4. Leaving open areas with granulation t issie

formation. 5. Displacing a flap.

6. Perichondritis. 7. Meatal stenosis.

Meatoplas ty in Open-cavi ty

Tympano-mas to idec tomy

Since a meatoplasty can cause some bleeding, i can be deferred until the middle ear and mastoic work is completed, grafts are placed, and the dista third of the canal is packed. Meticulous hemostasi: should be exercised. In an open-cavity mastoide': tomv, a Korner's flap is quite useful in providing skin coverage for the newlv created mastoid cavity. The flap is developed by making vertical incisions in the skin of the external auditorv canal at 6 and l'1. o'clock with a straight canal knife. They are con­nected by a horizontal incision made with a curved canal knife at 5 mm from the tympanic annulus (Fig". 7 - 9 A ) . 1 he vertical incisions are then extended to the conchal bowl (Fig. 7 - 9 8 ) . It is important to keep the base of the flap wide at the conchal bowl level. Th«( subcutaneous tissue of the flap is generally quite thick. It can be thinned carefully with a sharp scissors or scalpel, avoiding damage to the overlying skir (Fig. 7 - 9 C ) .

An opening is considered adequate when (hi surgeon's index finger can be introduced easily into the meatus. For practical purposes, a meatus canno< be made "too wide"; there is always a tendency toward reduction in size (narrowing). In order to keep the meatus open and provide better apposition of tissues for healing, two permanent sutures can be placed, bringing together the subcutaneous layer with the posterior margin of the postauricular inci­sion (Fig. 7 - 9 D ) . It is important to prevent postop-

Surgical Approaches to the External Ear Canal and Middle

FIGURE 7 - 9 .

140 Surgical Approaches to the External Ear Canal and Middle Ear

erative stenosis by controlling formation of granula­

tion tissue. Clean edges of the flap and good skin

coverage of the mastoid bowl are of paramount

importance. A Thiersch graft can be performed dur­

ing the primary procedure for these purposes, or

after three weeks if open areas with granulation

tissue are present; this should be necessary only

occasionally. (See the discussion of the Thiersch graft

in this chapter.) A steroid-saturated, firm pack is

applied and left in place for two weeks; upon its

removal, all granulations (if any) are curetted and/or

cauterized, and a steroid-antibiotic ointment is ap­

plied. Frequent and meticulous postoperative care is

bask to successful healing in meatoplasty and in

mastoid cavities in general.

An additional point: If a Korner's flap is not used

in a postauricular approach, a horizontal incision can

be made in the bony cartilaginous junction with two

vertical incisions at 6 and 12 o'clock, creating a

rectangular flap (Fig. 7 - 9 E ) . With this flap, the basic

principles described above apply equally. Other

types of flaps can be used according to need, such

as a vertical incision, an inverted T, or an inverted Y

(Fig. 7 - 9 F ) . Regardless of the flap used, the important

point is to provide adequate skin coverage for the

newly created surface area, ft is crucial to remember

that the meatus also comprises cartilage and bone;

that the flap is an important part, but only a part, of

the meatoplasty. Despite a flap that is beautifullv

designed "on paper," an inadequate meatoplasty

may result because of lack of attention to the under­

lying subcutaneous tissues, cartilage, or bonv mea­

tus.

Meatoplasty in Closed-cavity

Tympano-mas to idec tomv

An endaural Lempert I incision is made at a level

approximately 7 mm below the mastoid cortex level.

A Lempert II incision is made that is large enough

to admit the surgeon's forefinger freely. The bonv

canal, especially the posterior bony canal, is enlarged;

conchal cartilage is then removed by carefully evert­

ing the conchal skin and using a sharp scissors or

scalpel (Fig. 7 - 1 0 ) . Packing, suturing, and postoper­

ative care are identical to those for an open-cavity

mastoidectomy.

Management of Pitfalls and Complications

A torn skin flap or a flap with poor vascularity

due to a thin base may not survive; however, a thin

flap may, behaving for all practical purposes as i

skin graft. Lack of flap survival necessitates surgicrl

debridement and a Thiersch graft. Excessive bleedin ;

may lead to infection or appearance of granulation

tissue, or both; if bleeding occurs underneath th'-'

flap, the flap may become medially displaced. An

"organized clot" often leads to fibrosis, calling fo •

careful elevation of the flap, meticulous hemostasia. .

debridement, and tight packing. Fibrosis also can

occur when using a tight packing, but there will be

no secondary problems, provided that the packing is

removed at the proper time (no longer than twe

weeks afterward). Management of open areas witl

granulation tissue has already been described. On

occasion, especially when an infected mastoid h. 'j

been dealt with, a perichondritis might occur, cha'-

acterized by edema, induration, and pain over tr ^

entire pinna. In early stages, the possibility of allergy

to the antibiotic ointment or solution must be consic -

ered. These signs (misnamed "cellulitis") requir •

change of antibiotic solution, systemic antibiotic?,

daily (at least twice) soaks with Burow's solution c-

any astringent solution, and application of packing

saturated with antibiotic steroid solution. If t ly

symptoms progress (which they rarelv do), debride

ment, drainage, and placement of drains may be

needed. Cultures should be obtained, if possible.

If general principles, including adequate follow .'•

up, are not observed, meatal stenosis requiring i

revision may occur. The meatal skin is carefulh

elevated, the underlying bone (which usually dis

plays new bone formation, bony spicules, ridges

and so on) widelv drilled or curetted, and a largf

meatus developed. Remember that for practical pur

poses a meatus cannot be made too large, only too

small.

Thiersch Graft

Granulation tissue may develop in the mastoid

cavity after canal-wall-down mastoidectomy. Drain­

age may persist from granulation tissue until the

entire mastoid cavity is epithelialized. A Thiersch

graft is a thin skin graft that helps to epithelialize

and eliminate drainage from the mastoid cavity.

Aim

Placing a thin skin graft in the mastoid cavity in order to achieve complete epithelialization.

Surgical Approaches to the External Ear Canal and Middle Ear 141

Cartilage

RGURE 7-10.

Highlights Operative Procedure

1. Remove infected granulation tissue.

2. Harvest thin skin from the upper medial arm.

3. Cut the skin into proper sizes on Owen's silk.

4. Cover the entire non-epithelialized mastoid cav­

ity surface with the skin graft.

The procedure usually is carried out under local

anesthesia. Local injection of 1% lidocaine with

1 : 1 0 0 , 0 0 0 epinephrine, combined with topical appli­

cation of 4% cocaine solution soaked in 1/2-in gauze

strip, provides adequate anesthesia.

Pitfalls

1. Inadequately removing infected granulation tis­

t e .

2. Harvesting too-thick skin.

Debr idement of Granulat ion Tissue from Masto id Cavity

The mastoid cavity is irrigated with warm saline

to remove any debris or mucopus. Using cupped

forceps, ring c tre t s , and suction tips, all infected

granulation tissue and necrotic tissue is removed;

Surgical Approaches to the External Ea

FIGURE 7-11

Surgical Approaches to the External Ear Canal and Middle Ear 143

any thin, clean, raw tissue over the bone is left intact

(Fig. 7 - 1 1 / 4 ) . Hemostasis is obtained with 1:1000

topical epinephrine (Adrenalin) soaked in 1/2-in

gauze strip.

Harvest ing Thin Skin

After the mastoid cavity is cleaned out and while

hemostasis is being attained, thin skin is harvested

from the medial upper arm. Local anesthesia is

obtained with 1% lidocaine with 1:100,000 epineph­

rine injection. The authors use a razor blade held in

a clamp to harvest very thin strips of skin (Fig. 7-

11B). In order to obtain a thin skin graft, the razor

blade is pressed down only by the weight of the

instrument and a slicing motion is used. The area of

the upper arm where the skin is harvested is made

tight by pulling the lateral part of the arm with the

surgeon's free hand. A thin coat of mineral oil over

• the skin helps to harvest thin pieces of skin. The

area of the mastoid cavity requiring a skin graft

determines the amount of skin to be harvested; the

donor site is then dressed with scarlet red or Xero-

form gauze dressing. The thin pieces of harvested

skin are laid on a piece of Owen's silk impregnated

with gentamicin sulfate (Garamycin) ointment, and

placed on an upside-down Petri dish (Fig. 7 -11C) .

Extreme care should be taken to lay the skin on the

Owen's silk with the shiny dermis side up. The skin

and Owen's silk are then cut into the proper size

(usually about 0.5 cm) with a sharp scissors.

Skin Graft of Masto id Cavity

The gauze strips soaked in topical epinephrine

solution a^e removed from the mastoid cavity. The

pieces of skin and Owen's silk are placed over the

raw tissue|in the mastoid cavity with the dermis side

down (toward the bone) and the Owen's silk up (Fig.

7 -11D) . The entire nonepithelialized surface of the

mastoid cavity is covered carefully; slight overlap of

coverage is acceptable. An eye patch dressing is then

applied over the ear.

Postoperat ive Care

The pieces of Owen's silk are removed in two

weeks. If the skin has taken well, drainage is ended

and only routine care of the mastoid cavity is re­

quired.

FIGURE 7-12.

144 Surgical Approaches to the External Ear Canal and Middle Ear

FIGURE 7 - 1 2

This section at the level of the footplate shows a

dehiscent and bulging facial nerve over the stapes

crura (the most common area of dehiscence). This

photomicrograph serves as a reminder of the impor­

tance of thorough visualization before any drastic

procedures are performed. The facial nerve can be

dehiscent in other areas as well, such as adjacent to

the tensor tympani, in the facial recess, and in the

medial wall of the anterior epitympanic r< cess. A

dehiscent nerve can result in facial paresis or paral­

ysis in cases of acute otitis media, and represents a

potential complication in otologic surgical proce­

dures.

FIGURE 7-13

This section shows a focus of otosclerosis, but in working vigorously and blindly in the eusiachian

more importantly a dehiscent carotid artery (parallel tube area since complications could be disastrous.

arrows). Although this is uncommon, there is a risk

Surgical Approaches to the External Ear Canal and Middle Ear 145

FIGURE 7 - 1 4

This section shows the presence of a persistent

stapedial artery immediately medial to the footplate

in a middle ear with thickened mucosa and a dehis­

cent facial nerve. This persistence (representing per­

sistence of the embryonal hyoid artery) ts rare and

should not be confused with a normal small arterial

branch that crosses the footplate. Adequate v.suali-

zation and careful dissection are crucial when ex­

ploring an ear with chronic disease.

Pertinent Histopathology

SECTION IV

Specific Surgical Approaches

CHAPTER 8 External Ear Canal Procedures Canalplasty

A canalplasty is a procedure that normalizes the external auditory canal by removing abnormal bony growth such as exostosis, removing and replacing intractably infected skin of the canal, or enlarging and straightening a severely stenotic and tortuous canal. Meatoplasty may be done at the same time.

Aim

To restore the normal width and contour of the external auditory canal and, sometimes, to replace diseased with healthy skin.

Surgical Steps

1. Endaural or postauricular incision. 2. Elevation of canal skin flap. 3. Widening of the bony canal. 4. Placing back the canal skin flaps or skin graft. 5. Packing and closure.

Pitfalls

1. Exposing the temporomandibular joint capsule

anteriorly.

2. Opening into the mastoid air cells. 3. Damaging the tympanic membrane, ossicles, or

skin flaps.

Operative Procedure

The procedure usually is carried out under general anesthesia but can also be done under local anes­thesia. In either case, local injection of 1% lidocaine with 1:100,000 epinephrine is made into the four quadrants of the external auditory canal. Either an endaural or postauricular approach can be used.

Exostosis

Large exostoses can cause retention of cerumen, recurrent inflammation of the canal skin, and even conductive hearing loss. An endaural approach usu­ally is adequate. A posterior skin flap is developed from the bony cartilaginous junction to the annulus of the tympanic membrane (Fig. 8-1A) . The skin over the exostosis is elevated and preserved. When the exostoses are too large to permit a canal incision, a separate incision is made on the top of the exostoses paralleling the annulus of the tympanic membrane. Two skin flaps are developed over each exostosis, one laterally and the other medially based.

When the posterior bony canal with exostosis is exposed, the exostosis is drilled out with a cutting bur and diamond bur under continuous irrigation (Fig. 8 -1B) . As the base of the exostosis is removed, the entire tympanic membrane can be visualized and

150 External Ear Canal Procedui

FIGURE 8-1

External Ear Canal Procedures 151

the canal skin flap becomes better defined. The annulus of the tympanic membrane is left intact, and the middle ear is not entered. The remaining bony canal wall is smoothed down until the canal has a normal, even contour.

Any other exostoses in the canal are removed in a similar manner. This is usually easier because the canal is less crowded and the tympanic membrane is readily visible. For an exostosis in the anterior canal, a laterally based anterior "window-shade" flap can be developed starting from an area just lateral to the anterior half of the tympanic ring. When drilling the anterior wall of the canal, care must be exercised not to enter the temporomandibular joint.

After all the exostoses are removed and the rest of the canal wall is smoothed down, the skin flaps are laid back (Fig. 8 -1C) . The external auditory canal is packed with Gelfoam saturated in antibiotic solu­tion and "wrung out"; Owen's silk strips and pieces of cotton packing (rosebud packing) also can be used. The lateral part of the canal and the meatus are packed with 1/2-in gauze strips saturated with anti­biotic ointment.

The incision is closed in layers and a mastoidec­tomy type of pressure dressing is applied.

Intractable External Otitis

This procedure is indicated when chronic external otitis is persistent despite aggressive medical treat­ment. Usually the canal is obliterated with swollen, thick canal skin. The operation is usually performed under general anesthesia. Local injection of 17c li-docaine with epinephrine helps hemostasis.

A postauricular incision is made for wide expo­sure. The cartilaginous canal is sectioned at the level of the mastoid cortex through the postauricular in­cision (Fig. 8-2/1) . An infected stenotic plug of canal skin is removed using an elevator and curets (Fig. 8-28 ) . The thin epithelial layer over the tympanic membrane is also carefully peeled off; this can be done concurrently with canal skin removal or sepa­rately. The utmost care must be taken to avoid perforating the tympanic membrane. If a small tear occurs the edges are approximated; for larger defects a fascia graft might be needed (see Chapter 12). The best treatment is prevention.

The bony canal is enlarged with a cutting bur. The canal is drilled as much as possible until the entire tympanic membrane is visible; care must be exercised not to enter the temporomandibular joint anteriorly and the mastoid air cells posteriorly.

A meatoplasty is performed by removing the in­fected narrow meatus and conchal cartilage (Fig. 8-2C). The anterior cartilaginous canal skin up to the

tragus also can be removed if infected. The meatus should be large enough to admit a forefinger.

After the infected canal skin and the meatus are removed and the bony canal wall is smoothed down, a split-thickness patch of skin of 0.01-in thickness is harvested from the upper medial surface of the arm with a Daf'ilva dermatome. It is better to err on the side of thinness when harvesting since thinner skin takes better than thicker skin. The harvested skin is laid on a wooden tongue blade and cut into two unequal pieces. The larger piece is laid out on the drumhead and covers from the anterior annulus to the entire posterior half of the canal; the smaller piece covers the rest of the anterior half of the canal (Fig. 8 -2D) .

A double packing method is used. The first pack­ing places strips of Owen's silk and antibiotic-satu­rated cottons through the postauricular exposure. Gelfoam saturated in antibiotic solution and "wrung out" can be used instead of rosebud packing. After this packing is placed, the excess skin is folded over the pack and the postauricular incision is closed (Fig. 8 - 2 E ) . Under the operating microscope, the folded grafted skin is laid over anteriorly toward the tragus and posteriorly toward the concha. Any excess skin can be trimmed off. The second pack is placed endaurally (Fig. 8 - 2 F ) . All raw bone is covered with skin graft, and a pressure dressing is applied over the ear. The packs are removed after two weeks. Crusting may occur for several weeks and requires meticulous removal and cleansing until definite heal­ing is achieved.

Stenot ic Canal

The external auditory canal may narrow owing to the presence of scar tissue without infection. This stenosis can cause conductive hearing loss and sec­ondary ear canal cholesteatoma.

The operative procedure is similar to that for exostosis. The posterior canal skin flap is developed from the bony cartilaginous junction to the annulus, from the 12 to the 6 o'clock position. The bony canal is smoothed off with a drill and the skin flap is laid back. Anteriorly a window-shade flap may be nec­essary. Packing, dressings, and postoperative care are the same as for exostosis.

Tumors of the External Auditory Canal

The external auditory canal may be involved with benign or malignant tumors. The surgical treatment

152 External Ear Canal Procedures

FIGURE 8 - 2 .

External Ear Canal Procedi),

of these tumors depends on the type and their location in the canal.

Aim

To achieve complete removal of the tumor and restore a normal external auditory canal whenever possible.

Surgical Steps

1. Biopsy of the tumor. 2. Complete removal of tumor with or without

parotidectomy, mastoidectomy, or temporal bone resection.

3. Split-thickness skin graft. 4. Packing and closure.

Pitfalls

1. Inadequately excising a malignant tumor.

2. Delaying the diagnosis. 3. Causing unnecessary damage to the tympanic

membrane, ossicles, or temporomandibular joint. 4. Leaking of cerebrospinal fluid after temporal

bone resection.

Operative Procedure

Biopsy

The location, size, and extent of a tumor in the external auditory canal should be thoroughly evalu­ated. If otalgia or bleeding is associated with the tumor, malignancy should be suspected. New im­aging techniques such as computed tomography (CT) or magnetic resonance (MR) are helpful in defining the extent of the tumor. Biopsy should follow after a thorough examination under an operating micro­scope, and can be done under local anesthesia using a cup-biting forceps (Fig. 8-3/4). If the lesion is small and has not penetrated to the underlying bone, an excisional biopsy that includes removal of surround­ing canal skin should be adequate (Fig. 8 -3B) .

Anter ior Canal Tumors

If benign, the tumor with surround!^ canal wall skin is removed. The e x c ' s i o n ^ ^b"" extended up to the tragus and over th, e

n 6

membrane by denuding the epithelial k " " m c

drumhead (Fig. 8 -3C) . The bony canal i ^ " id e r i d with a drill, arid a split-thickness skin gr^f ( Q j q „ j in thickness from the upper medial arm • ;

is used to cover the exposed bone and the drumht, , 3D). , d ( F l S - * -

If the tumor is malignant, lymph^j. through Santorini's fissures into the " ,

u feauriculsr nodes can be assumed. Adequate exc i s i r j | i

elude a superficial parotidectomy and r e r t \ 0 v ! j 0 j 'u~ anterior canal wall. If a CT scan shows ^ e

has extended anteriorly and medially, t^ , m o r

should include the cartilaginous and bo^ ant'e^'o11

canal wall, the anterior drumhead, the lobe of the parotid gland, and the conq . " l c ' a

mandible (Fig. 8 -3E) . The facial nerve \ h

y e ° e

f™j whenever possible; if involved with h j . ^ . . included in the excision and repaired vv-^ _J graft. The canal defect is covered with a _

, . split-thick-ness skin graft. r

Posterior Canal Tumors

Benign tumors involving the c a r t i l a g i t \ Q u s

rior canal can £e excised with a margin ( p . U S

If the defect is large, a split-thickness skit\ , b e used. When a tumor i s i n the posterior l " m a y closer to the tympanic membrane, wid^ aj-eas f posterior canal.skin with the epithelial l f y e r Q j ^ drumhead can'be removed and a sp l i t - thu;^ n e s s

graft is applied! The posterior canal can b e 'j with a drill before the skin graft is applieq

When a malignant tumor is small a r ^ extended to tfce drumhead, a complete j j . . radical mastoidectomy is done. If the t u r t | 0 r . ' . i e

to the drumhead a radical mastoidectomy ; . o s e

t c i * L L . . . j • l s done. If a malignant tumor is extensive and l r lv 0 lves he

middle ear or mastoid, a subtotal or total bone resection may be necessary. "

Subtotal Resection of Temporal Bone

The external auditory canal with s u r r o u r , ^ ^ and bone is removed, leaving the facial r » ^ r v e m j a c (

The incision is made anterior and pos ter ,^ ( q ' auricle, with the inferior extension along tk,e a n t e r o

border of the sternocleidomastoid muscl e p. 4A). The auricle is elevated superiorly, leav;

External Ear Canal Procedures

FIGURE 8-3.

External Ear Canal Procedures 155

FIGURE 8-4.

156 External Ear Canal Procedures

of tissue from the canal and meatus. A wide area of mastoid cortex is exposed, along with the parotid gland and the facial nerve as it exits from the stylo­mastoid foramen. Using the operating microscope and drill, the entire mastoid portion of the facial nerve is exposed. The bony canal is isolated and separated from surrounding structures. Anterosu-periorly, the bony buttress of the zygomatic process of the temporal bone is drilled down. Anteriorly, the capsule of the temporomandibular joint is separated from the canal wall. The malleus is removed along with the tympanic membrane; the incus may be left intact or removed, depending on the extent of the tumor. Drilling is continued just anterior to the facial nerve, as in the extended facial recess approach. Interiorly, the dissection is limited by the jugular bulb. The specimen is separated as drilling continues just above the bony annulus (Fig. 8 -4B) . After the specimen is removed, the middle ear space and exposed dura are covered by a large temporal fascial graft (Fig. 8 -4C) . The fascia is held in place by a rosebud or Gelfoam pack and the wound is closed.

Total Temporal Bone Resection

After the incision is made, the auricle is elevated with the superiorly based flap. Wide areas of the zygomatic arch, the squamous portion of the tem­poral bone, and the mastoid are exposed by elevating the temporal muscle (Fig. 8-5 ,4) . The lower limb of the incision is made and the parotid gland is exposed. The internal jugular vein is exposed by detaching the sternocleidomastoid muscle from the mastoid tip. The arch of the zygoma is removed and the middle fossa dura is exposed by drilling on the squamous portion of the temporal bone; this opening is en­

larged with a rongeur. Elevation of the dura roni the temporal bone allows the tumor to be evali ated for possible intracranial extension (Fig. 8 -5B) . The head of the mandible is removed. If the turno. has invaded the anterior canal, a total parotidectoriy is done; the facial nerve is resected and the post*rior belly of the digastric muscle is severed (Fig. 8- 5C). The internal carotid artery is exposed with a Irill; during this procedure the bony eustachian tut e is transected (Fig. 8 -5D) . The bone over the internal carotid artery is removed with the points of the artery's entrance into the foramen lacerum defining the anterior and superior limits of the resection i Fig. 8-6/1) . A mastoidectomy is performed, exposing the sigmoid sinus with a drill (Fig. 8 -6B) . The speciraen is removed by fracturing the temporal bone thro igh the otic capsule with a chisel placed just p o s t e r i c to the internal carotid artery. Hemorrhage is contro led with packing. The boundaries of the resection are the internal carotid artery anteriorly, the middle fossa dura superiorly, the posterior fossa dura and sigmoid sinus posteriorly, and the petrous apex medially (f ig. 8 -6C) . The line of resection as seen from abo 'e, passes through the petrous portion of the tempo'al bone just lateral to the internal auditory canal. If the tumor extends to the dura, the involved portion may have to be resected; if there is evidence of metastasis to the neck, a radical neck dissection may be neces­sary. The wound is closed after the defect is filled with temporal muscle and a large meatoplasty is done (Fig. 8-6D) . A split-thickness skin graft ov^r the temporal muscle will shorten the healing time. If the tumor extends to the auricle, the entire auricle and its surrounding skin are excised (Fig. 8 - 6 E ) . The defect is best covered with a myocutaneous flap fro n the greater pectoral muscle.

External Ear Canal Procedures

FIGURE 8-5 .

FIGURE R-6.

CHAPTER 9 Congenital Atresia

Congenital aural atresia remains one of the most challenging (and rewarding) of all otologic problems. With the eventual incorporation of fully developed bone conduction aids, the indications for surgery may vary; it is essential, however, to have a clear understanding of the main surgical points and con­cepts. A full discussion of the subject would require a detailed review of embryology types and forms of atresia and their surgical indications and timing. This is outside the scope of this atlas.

The basic requirements for undergoing surgery include:

1. Pneumatization of the mastoid. 2. Adequate cochlear function. 3. A cooperative patient with a supportive family.

Surgical Technique

Aims

1. To achieve a large meatus. 2. To achieve a self-cleansing mastoid cavity that

can be easily visualized through the meatus.

3. To avoid post-operative stenosis. A large mea­toplasty, skin grafting of the cavity, and close follow-up are important favorable factors.

Highlights

1. The middle ear cavity is approached from the mastoid and not by drilling directly over the atretic canal.

2. In many patients the temporomandibular joint

is posterior to the auricular remnant. This requires surgical incisions that allow final positioning of the ear canal anteriorly to the remnant, and of the remnant posteriorly to the temporomandibular joint.

Procedure

The Z-plasty technique shown in Figure 9-2A allows repositioning of the auricle posteriorly and of the ear canal anteriorly to the auricular remnant. When the Z-plasty is completed, self-retaining re­tractors are applied and the mastoid cortex is iden­tified. This is a crucial point. It is essential to have a clear anatomic picture before initiating any drilling. The linea temporalis usually is identifiable; drilling is begun anterior to it. The absence of adequate landmarks can lead the surgeon to explore, and become lost in, the temporomandibular joint space without finding the middle ear cavity. This poten­tially can result in transection of the facial nerve.

Another important precept is that the atretic canal must not be drilled directly. Pneumatization of the mastoid is required because the essential procedure to be done is an open-cavity mastoidectomy, which allows safe drilling and identification of the facial nerve, lateral semicircular canal, and middle ear "from behind" (Fig. 9 - 1 ) . Drilling directly into the atretic plate carries a significant risk of damaging these structures. The atretic plate is removed care­fully while the mastoid drilling is being done (Fig. 9 - 2 ) . A tympanic remnant may or may not be pres­ent, and the middle ear cavity may be quite small. Extreme care must be taken not to injure the ossicles, which may be wholly or partially present, fused, or absent. Once the ossicles have been identified, their mobility is assessed and reconstruction of the os-

Congenital Atresia

FIGURE 9 - 1

Congenital Atresia

FIGURE 9 - 2 .

162 Congenital Atresia

FIGURE 9 -3 .

Congenital Atresia 163

FIGURE 9 - 4 .

sicular chain is planned accordingly (see Chapter 5 ) .

The facial nerve not uncommonly is found to have an abnormal angulation in the second genu, making a turn of 60 degrees rather than 120 degrees (Fig. 9-3/1). This occurs because the nerve has a smaller middle ear cleft to encircle; therefore it makes a sharper angle (60 degrees) and exits inferiorly near the glenoid fossa, in a more lateral position.

Once the mastoidectomy has been performed, the lateral semicircular canal and facial nerve identified, the middle ear cavity enlarged, and an ossiculoplasty done, grafting of the tympanic membrane is per­formed. Temporal fascia is placed over the recon­structed ossicles; the fascia must not be excessive, in order to avoid adhesions and lack of ossicular mo­bility (Fig. 9-3D) . The mastoid cavity itself either is left "raw" for an eventual Thiersch graft or is grafted primarily at the same time. The cavity is packed as described in previous chapters, and the incisions are closed with appropriate sutures (Fig. 9 - 3 E , F ) .

Once again it should be mentioned that a large meatus is very important; for practical purposes a meatus can almost never be made too large.

Pertinent Histopathology

FIGURE 9-4

A horizontal section of the temporal bone of an individual with congenital atresia and malformation of the auricle. Mondini's dysplasia also is present. The magnitude of compromise is severe. Absence of the incus, stapes, and oval window can be noted. The facial nerve also is absent; this can be seen only in the internal ear canal (not shown here), since the facial nerve does not course through the temporal bone.

CHAPTER 10 Surgical Procedures in Different Forms of Otitis Media

Clinical experience and laboratory studies indicate that middle ear effusions, far from being innocuous, are slightly delayed reflections of severe underlying histopathologic changes in the mucoperiosteum. They are part of a continuum in which some forms of otitis lead to others, resulting in complications or sequelae. The immediate purpose of the surgical procedures described in this chapter primarily is to halt this process, and to help in the regression of middle ear histopathologic changes. The ultimate goal is to arrest the continuum medically, thus re­serving surgery for the restoration of function rather than the mere eradication of active disease.

This chapter begins with a description of a myr­ingotomy and insertion of ventilation tubes. Because this seems on the surface to be the simplest of surgical procedures, it can be, and usually is, treated lightly by surgeons. The procedure is detailed pur­posely in excess in order to develop a "conscience" in surgeons about the significance and extreme im­portance of this "little operation," which has changed the course of otologic practice and helped to reduce significantly the number of major otologic procedures for complications or sequelae of otitis media. The chapter concludes with a scries of horizontal sections of temporal bones, highlighting the underlying changes in the mucoperiosteum that take place be­hind an apparently benign "middle ear fluid."

Myringotomy and Tubes

Myringotomy is an incision of the tympanic meri-brane.

Aim

To substitute fo r the function of the eustachian tube—that is, to provide ventilation and drainage fi r the middle ear. By providing aeration to the middl ? ear space, the intent is to reverse the patholog' : changes of the middle ear mucosa and prevent sub­sequent complications or sequelae. A myringotomy also provides symptomatic improvement, confirms i diagnosis, and allows aspiration of middle ear fluid (which can also be diagnostic) and insertion of ven­tilation tubes.

Indications

1. Persistent effusion that has failed to respond tc adequate nonsurgical therapy.

2. A poorly ventilated middle ear even when fluH \

Surgical Procedures in Different Forms of Otitis Media 165

is absent, but the patient is symptomatic or the

tympanic membrane is retracted, or both. A good

and not uncommon example is that of airline pilots

or attendants with eustachian tube dysfunction

(or individuals subjected repeatedly to pressure

changes), who are otherwise asymptomatic.

3. Recurrent otitis media, even when normal con­

ditions exist between episodes.

4. Acute suppurative otitis media with a bulging

or insufficiently perforated tympanic membrane; the

patient is markedly symptomatic. (A myringotomy

alone is performed.)

5. For diagnostic purposes in infants with fever of

unknown origin.

6. To correct conductive hearing losses due to

effusions.

7. A retracted tympanic membrane before the

stage of atelectasis.

8. With a tympanoplasty in patients with tubal

dysfunction.

•9. Otitis media with facial paresis or paralysis or

other impending complications.

Instruments

1. Set of aural specula.

2. Suction tubes (5- , 20- , and 7-gauge).

3. Myringotomy knife.

4. Baby alligator forceps.

5. Blunt pick (straight or angled).

6. Small ring curet.

Procedure

First, inspect and visualize (this means to pur­posefully look and screen and not to glance casually) the ear canal. Cleanse the cerumen and epithelial debris very carefully; dry, crusty cerumen can be washed and loosened with saline or hydrogen per­oxide. Abrupt cleansing can cause bleeding or small hematomas in the ear canal. Insert the proper ear speculum (see Chapter 6) and carefully scrutinize the four quadrants of the tympanic membrane (Fig. 1 0 -1/1). Look for perforations, retraction, and retraction pockets, and for characteristics of the drum itself, such as myringosclerosis, monomeric areas, atrophic changes, evidence or suggestion of a dehiscent jug­ular bulb, evidence of a reddish mass in the anterior or anteroinferior areas (dehiscent carotid artery), or myringostapediopexy. Once it becomes a habit, this

inspection does not take time and can avoid a number

of problems. Look first; do the preparatory work;

then—and only then—proceed with the operation.

Initially, a magnification of 6x will suffice. In

general, the authors tend to use higher power, which

provides a better view of sections of the membrane

(once the area has been inspected and the site of

incision selected).

Incisions

The incision should not be made in the postero-

superior quadrant because of the underlying incu-

dostapedial joint and stapes, nor should it be made

too close to the annulus because this favors early

extrusion of the tube (unless that is the purpose). An

incision should not be made in the presence of acute

infection, again because of the risk of early extrusion

(unless only drainage is intended).

Epithelial migration can be considered for practical

surgical purposes as radiating from the umbo. Mi­

gration is slowest in the anterosuperior quadrant,

followed by the anteroinferior and posteroinferior.

For this reason, the incidence of persistent perfora­

tion is higher in the anterosuperior quadrant. Since

migration is not the only factor in extrusion of the

tubes, the benefits of using this quadrant should be

judged on a case-by-case basis. In addition, surgical

repair of perforations in this quadrant is not so simple

as in other quadrants. The surgeon must decide

whether, in a particular case, a larger flange tube (for

example, a Paparella No. 2) in the anteroinferior or

posteroinferior quadrant would be more beneficial

than a No. 1 tube in the anterosuperior quadrant.

In the middle ear space, incisions should not be

made in the umbo because of its close proximity to

the promontory. The widest space available is the

hypotympanum (Fig. 10-1B); this must be considered

when there is retraction of the tympanic membrane.

In such a case, incisions in this area allow better

drainage and more space, and carry less risk of

middle ear structural damage.

The length of the incision depends partly on the

type of tube to be used; in general, it should be the

same as the diameter of the inner flange of the tube.

Too short an incision can precipitate tears when the

tube is placed, especially in a weakened or atrophic

membrane (Fig. 10-2/1) . Too long an incision might

preclude a tight fit around the tube, allowing it to

extrude or even fall into the middle ear cavity (Fig.

10-2B). Paparella-type tubes that have a small inden­

tation in the inner flange can be placed through a

small incision and rotated with baby alligator forceps

or a blunt pick ("screwing motion").

FIGURE 10-1

Surgical Procedures in Different Forms of Otitis Media 167

FIGURE 10-2.

168 Surgical Procedures in Different Forms of Otitis Media

A sharp myringotomy knife should be used. Inci­sions can be made radially or circumferentially (Fig. 1U-1C). Circumferential incisions tend to accumulate more epithelial debris, leading to earlier extrusion of the tube. In cases of acute purulent otitis a wide circumferential (smile) incision is preferred, since drainage alone is the purpose and prompt closure is desired. In all other circumstances, a radial incision is preferred, since it sections fewer fibers, runs par­allel to most of the blood vessels irrigating the mem­brane, and causes less scarring.

The tip of the knife should be inserted just far enough to section the membrane; deeper incisions might damage the middle ear mucosa (Fig. 10-1D, £ ) . If there is localized bleeding (thicker membranes sometimes bleed) and blood obscures the incision,

'hydrogen peroxide or cotton saturated with epineph­rine, or both, will control it.

Tubes

Tubes should be placed in a normal area of the membrane. Special care should be taken to avoid atrophic or monomeric areas. Myringosclerotic areas tear easily and tubes do not hold well. In contrast, tubes in normal areas that are surrounded by sclerotic plaques tend to stay in place for long periods.

Before inserting the tube, as much middle ear fluid as possible should be removed. Markedly retracted tympanic membranes tend to have small amounts of this serous fluid. A No. 5 suction tip can be used, placed barely through the incision while trying to avoid enlarging the incision or causing localized bleeding (Fig. 10-2C). If the middle ear cavity is to be entered with a suction tip, the smaller No. 20 is preferable. Excessive suctioning can also cause mu­cosal bleeding. With thick mucoid effusions, a No. 5

suction tip may be insufficient. In some cases a baby alligator forceps, or a No. 7 suction tip placed im­mediately above (not through) the incision, can be useful (Fig. 10-2D). Occasionally a counterincision that allows air to enter the middle ear cavity while the fluid is suctioned is helpful. When fluid is not completely removed by one incision, a small incision in a different quadrant may be more effective in removing loculated fluid than "fishing" in the middle ear cavity with a suction tip. Some authors consider counterincisions undesirable, but in the authors' ex­perience a small incision consistently heals well. It is important to make a clean incision and to approxi­mate the edges carefully. A small piece of Gelfoam saturated with a drop or two of blood can be used to cover the incision. In thick, cloudy mucoid effu­sions, a No. 2 tube is placed; this tube is also used

in infected effusions with facial palsy. Cultures also should be obtained in these cases. It is a good habit to visualize the middle ear mucosa through the incision.

The canal, the tympanic membrane, and eveo. the middle ear cavity can be irrigated with salin»j anti­biotic-steroid solutions, or hydrogen peroxide as needed. When used in the middle ear cavity, anti­biotic solutions should be neutral (not acid); < ther-wise there may be considerable postoperative pain (or intraoperative pain if local anesthesia is used). Ophthalmic drops are useful. Ototoxic antib.otics should be avoided.

Types of Tubes

There are many kinds of tubes of different she pes, sizes, and materials, ranging from "homemade" polyethylene to Silastic, Teflon, or metal; some ex­amples are shown in Figure 1 0 - 2 E - G . The type of tube is less important than the rationale for using it. In terms of size and shape, three types can be considered: short- , medium- , and long-term. L-.mgth of stay depends partially on the type of tube (except for permanent tubes, which are described elsevhore in this chapter). Additional important factors - O c f e d considered include the quadrant of insertion, c.mcfP tions of the membrane, and individual tympanic membrane migration, among others. The au hois have seen many so-called long-term tubes leid to eventual perforations requiring tympanoplasty.! has also been observed that shorter tubes with wide lumens tend to plug less and collect less epithelial debris than long-term tubes protruding from the tympanic membrane. In general, however, i lost well-designed tubes work well if they are pror erly used.

Cost of the tubes is also a factor. Variation * in price sometimes seem illogical. The authors I ave designed and used 18-karat gold tubes handmad? in Chile that are 200% cheaper than the least expen .ive plastic tube.

Placement of the Tube

With a baby alligator forceps, the tube is grasi •ed gently from its outer border or from a special ip. The incision should be clean and free of blood. The inner flange is laid sideways on the incision (proximal end) (Fig. 10-3A) . Sometimes it can be "popped" or "screwed" in with a gentle motion (Fig. 1 0 - 3 8 ) . Usually it can be laid over the proximal lip of the incision and then pushed in with a blunt pick, either by pressing it from its superior surface or by gently

FIGURE 10-3.

170 Surgical Procedures in Different Forms of Otitis Media

twisting it around (Fig. 10 -3C, D ) . Once the tube has been inserted, it is a good idea to rotate it to ensure that it is in position.

Once it has been verified that the tube is in place, it is a good idea to place a No. 20 (or smaller if needed) suction tip through the opening of the tube (Fig. I 0 - 3 E ) . Any middle ear fluid or blood should be suctioned and a few drops of hydrogen peroxide left in place. Postoperatively, the authors tend to recommend neutral pH drops for two or three days to ensure that patency is maintained. If there is any pain or discomfort with the drops, they are discon­tinued. If the fluid is cloudy or shows any signs of infection, do not hesitate to keep the patient on antibiotics (and culture the effusion). These appar­ently small details in technique can make a big difference in ventilation tube insertion.

Complications

Potential

As in most surgical procedures, the best treatment for complications is to prevent them. Excessive desire for speed is a potential surgical enemy, particularly harmful in tube insertion. Many unnecessary prob­lems arise in training programs because this "simple procedure" is left to the most junior and inexperi­enced surgeons. It takes time to learn how to use an operating microscope propcrlv and to see all thai must be seen. Mutual coordination ami understand ing with the anesthesiologist are essential. I he resi­dent should ask for help if his or her orientation and timing are inadequate; the anesthesiologist should understand that the purpose of the procedure is to protect the patient's ears, not the ancslhesiologist's hand.

Intraoperative

1. A small ear canal can make it difficult to visu­alize the whole tympanic membrane. Extreme care should be taken to avoid damaging the skin of the ear canal; bleeding will further obscure vision. A small ear speculum can be gently "screwed" in, and the speculum size gradually increased.

2. For lacerations, bleeding, or hematoma of the ear canal, carefully irrigate with hydrogen peroxide or apply small cotton balls saturated with epineph­rine, or both.

3. Facial paralysis due to injection of local anes­thetics is a temporary phenomenon of no conse­

quence, but the surgeon must be aware of ' lis annoying possibility.

4. For bleeding from the incision, use hydrogen peroxide or cotton balls saturated with epinephrine, or both.

5. If an incision is too long, approximate the borders carefully; if necessary, place small pieces of Gelfoam saturated with a few drops of blood and select a different site for the incision. Large tears and tears in myringosclerotic areas may require a tym­panoplasty.

6. For a too-deep incision causing mucosal bleed­ing, aspirate fluid and irrigate the middle ear w i h hydrogen peroxide or a few drops of epinephrine solution, or both. Use postoperative antibiotic-stero d drops.

7. If a tube has fallen into the middle ear cavit / , carefully recover it through the available incision or make a new incision if necessary. However, if it is lost in the cavity, if is better to leave it in or (rare! ' ) perform an exploratory tympanotomy than to fich blindly for it.

8. If bleeding occurs because of damage to a jugular bulb occupying the hypotympanum (either in a high location or medial to the tympanic mem­brane), immediate packing should be done, initially with Gelfoam and then with tight gauze packing. The Gelfoam layer helps to avoid further bleeding when removing the gauze pack. Do not panic, j. st pack.

4, Damage to the ossicular chain and damage ;o the facial nerve are uncommonly seen complicatio IS that reqtiire exploration; they are dealt with in e1 1-ferenl chapters.

Postoperative

I Short-term:

A. Inlccted ear drainage (purulent otorrhea) ir •.-mediately after surgery usually means that , n infected middle ear effusion or silent otil S media was present. Antibiotics (orally and top­ically) should be used. The same treatme'T should suffice for late purulent otorrhea.

B. Forcing the footplate into the vestibule in CAST 5 of previous myringostapediopexy (either spor -taneous or postsurgical) has been described The best treatment here, as for all other com­plications, is prevention; once it has occurred exploration is indicated.

C. Otalgia usually occurs with acid otic drops Neutral drops or ophthalmologic drops usualli suffice. The value of drops should be assessed on a case-by-case basis. On occasion, the dis-

Surgical Procedures in Different Forms of Otitis Media 171

comfort is caused by the drops dripping into the nasopharynx.

2. Long-term: A. Epithelial debris or cerumen blocking the tube

can be removed with a small hook under the microscope. It is a good idea to use otic drops and sometimes hydrogen peroxide to soften this debris before removal. Occasionally it dis­solves by itself and can be gently suctioned.

B. Treatment of a permanent perforation of the tympanic membrane varies. If the patient is a child with eustachian tube dysfunction and the perforation is clean and small, it may serve the purpose of a tube and should be observed carefully. If the perforation is larger or if the exposure of the mucosa requires further action, a tympanoplasty should be done, and possibly a tube should be placed at another site in the tympanic membrane.

C. Skin migrating into the middle ear cavity via the tube opening is a rare event that requires middle ear exploration, removal of tympanic membrane edges around the tube, and tym­panoplasty. On occasion, a congenital choles­teatoma appears as an apparent complication of tubes. Adequate preoperative radiologic evaluation and thorough middle ear explora­tion are crucial in such cases.

D. Extrusion of the tubes may be followed by recurrence of the original problems. In some cases tubes must be reinserted In other cases, tubes are poorly tolerated or are extruded shortly alter insertion; these might require so-called "Iransmeatal permanent aeration tubes." The indications are relative and should be assessed on a case-bv-ease basis. Some surgeons utilize "permanent" tubes through the tympanic membrane; these have a high incidence ol persistent perforation requiring an eventual tympanoplasty. Transmeatal tubes are preferred, but the indication for their use also is relative. The authors do not use per­manent tubes, preferring instead to reinsert a No. 2 tube in such cases. Because of their common use, however, insertion of permanent tubes is described below.

Transmeatal Permanent Aeration Tubes

Instrumentation is similar to that for stapedec­

tomy.

Aim

To place a tube beneath the annulus in the pos­

teroinferior quadrant.

Technique (Portmann)

With a curved canal knife, a horizontal incision is made parallel to the annulus, approximately 10 mm lateral to it in the posteroinferior quadrant (Fig. 1 0 -4A). A small flap is elevated and the middle ear cavity is entered beneath the annulus (Fig. 10-4B) . A small bur is used to drill a canal in the posterior bony wall. The tube is placed with the inner flange medial to the annulus (in the middle ear) (Fig. 1 0 -4C). The flap is repositioned and held in place with Gelfoam and antibiotic-saturated gauze (Fig. 10-4D). After one week the gauze is removed.

Complications

1. Those of pressure-equalizing (PE) tubes. 2. Edema of the skin that obscures the tube.

Treatment with topical antibiotics and steroids usu­ally solves the problem, allowing the tube to become visible again.

3. Blockage with debris or cerumen, or both. This complication is more common with permanent tubes than with regular tubes. Measures for removal of the blockage are similar to those lor regular tubes; how­ever, removal with hooks, requiring a local or general anesthetic, is more common. (This is equivalent to reinserting a No. 2 tube.)

In addition, a number of patients over time de­velop complications or sequelae involving the tym­panic membrane or middle ear, or both. These in­clude an atrophic or atelectatic tympanic membrane, myringosclerosis, chronic otitis media, cholesterol granuloma, disruption or fixation of the ossicular chain or tensor tympani tendon, and so on. Such complications highlight the need for periodic check­ups and close observation in the treatment of otitis media. In unresponsive cases or in those in which underlying middle ear pathology is suspected, there should be no hesitation in proceeding with explora­tory tympa lotomy; the surgeon should not sit and wait for a localized disaster to occur. Exploratory tympanotomy, tympanoplasty, and ossiculoplasty are described in different chapters in this book. Persistent dysfunction of the eustachian tube may lead to tympanic membrane retraction, thinning, and

Surgical Procedures in Different Forms of Otitis Media Surgical Procedures in Different Forms of Otitis Media 173

formation of adhesions of the membrane to the

promontory. A tympanoplasty for an atrophic or

atelectatic tympanic membrane (described below)

may be required. On occasion, persistent effusions

and underlying histopathologic changes may lead to

hypocellularity of the mastoid and lack of aeration of

the middle ear cavity. Once these are clinically and

radiologically documented, surgical procedures to

increase aeration—either a mastoidotomy or a cortical

("intact wall") mastoidectomy (described below)—

are recommended. Surgery for major complications

of otitis media is described elsewhere in this chapter.

Surgery for an atrophic or atelectatic tympanic

membrane can be performed using a transcanal,

endaural, or postauricular approach. Different meth­

ods can be used; two of the most common, cartilage

tympanoplasty and tympanoplasty for atelectatic

tympanic membrane, will be described. The basic

objectives are (1) to reinforce an exceedingly weak

tympanic membrane, which is usually collapsed and

not uncommonly attached to the medial wall of the

middle ear; (2) to inspect the middle ear cavity, repair

ossicles, and lyse adhesions (re-establishing func­

tion); and (3) to re-establish the middle ear space and

prevent further disease.

These measures, in turn, can be combined with

aeration procedures such as a cortical mastoidectomy

or mastoidotomy. The procedure and approach to

follow depend on the judgment, expertise, and pref­

erence of the surgeon.

A cartilage tympanoplasty will be described as a

transcanal procedure and a tympanoplasty for atelec­

tatic tympanic membrane (adhesive otitis) as an end­

aural approach, with the understanding that they

can be done either way or even by a postauricular

approach. Similarly, a cortical mastoidectomy or a

mastoidotomy can be done by an endaural or post­

auricular approach. It is important for the surgeon

to realize that different approaches can be used

interchangeably or combined as necessary; there are

so many forms of presentation in otitis media that a

"single surgical approach" can be, at times, a very

limiting concept. The two methods described only

suggest alternatives. The surgeon should decide

what is best for the patient and modify these ap­

proaches according to need.

Cartilage Tympanoplasty for Atrophic Tympanic Membrane

Surgical Steps

1. Transcanal incisions.

2. Tympanomeatal flap.

3. Widening of the bony canal.

4 . Harvest ing tragus (cart i lage-perichondrium

graft).

5. Elevation of the tympanic membrane.

6. Inspection of the middle ear cavity.

7. Inspection of the antrum and atticotomy-mas-

toidotomy, if necessary.

8. Placement of Silastic, Gelfilm, graft, and PE

tube (optional).

9. Packing and closure.

Highlights

1. Create a large tympanomeatal flap.

2. Carefully harvest and prepare a cartilage-peri­chondrium graft.

3. Perform a canalplasty.

4. Carefully elevate the thin tympanic membrane.

5. Adequately position the cartilage-perichon­drium graft.

Procedure

A large tympanomeatal flap is elevated with ver­tical incisions at 6 and 1 or 2 o'clock (Fig. 10-5/4) . A large flap is useful since an underlay cartilage-peri­chondrium graft extending into the posterior canal is to be used. The posterior canal may need to be widened. If necessary, the approach can be turned into a postauricular or endaural approach. If the posterior canal is not wide enough, the canal wall can be widened carefully with a bur (after elevating the flap). If an anterior bony overhang is present, a window shade is developed and the overhang re­moved (see Chapter 8). A wide and open canal favors visualization, postoperative healing, and even hear­ing (to a small degree).

A cartilage-perichondrium graft is harvested. This can come from different sources, the most common being the tragus. An incision is made in the dorsal (posterior meatal) side of the tragus, and by gentle, sharp dissection the tragus is isolated and a piece harvested (Fig. 10-5B) . The tragus has perichon­drium on both sides. An incision is made with a scalpel in one of the borders and the perichondrium on one side is elevated (under the microscope) with a duckbill, leaving the perichondrium as a single continuous strip with one side attached to the carti­lage (Fig. 1C-5C). The cartilage can be left as is or carefully thinned with a scalpel. It can also be com­pressed briefly and gently; if compressed firmly or for

Surgical Procedures in Different Forms of Otitis Media

FIGURE 10-5.

Surgical Procedures in Different Forms of Otitis Media 175

too long, the cartilage will separate from the peri­chondrium. The graft is preserved in saline. The tragal incision is closed with appropriate sutures after meticulous hemostasis with cautery (or ligation); oth­erwise, a localized hematoma may develop postop­eratively.

The tympanic membrane is very carefully elevated while trying to maintain its integrity. If the mem­brane has sclerotic plaques, they can be gently and meticulously removed with a joint knife or its equiv­alent. It is not imperative to remove all plaques; excessive removal can cause tears in the membrane. (To make matters worse, the membrane is poorly vascularized, so the surgeon must be careful here.)

Any adhesions are carefully sectioned. A No. 20 or 24 suction tip with the finger "off the hole" is used. The ossicular chain is inspected and, if neces­sary, reconstructed (see Chapter 12).

If the tympanic membrane is retracted or the tensor tympani is fixed, or both, the tendon is sec­tioned. (Fig. 10-5D). The main aim of this procedure is to mobilize the malleus and widen the mesotym-panic space. (This does not produce increased aera­tion.)

At this point, the attic and antrum are inspected (Fig. 10—5E). Palpation with a Whirlybird can give a good idea of the adequacy of communication be­tween the middle ear and the mastoid antrum. If there is any question, further inspection is made. It is not uncommon to find a so-called "aditus block" that obstructs communication and significantly im­pairs aeration despite the presence of an adequately sized mastoid cell system. An atticotomy is done, the extent of which depends on the degree of visu­alization needed. The attic is gently curetted down with stapes curets in a superior to inferior direction (away from the ossicles), which helps to avoid ossi­cular disruption. The attic is then inspected, adhe­sions are sectioned and removed, and the ossicles are freed of excessive adhesions and connective tis­sue. If there is any question of insufficient passage, the mastoid should be inspected. Some authors cre­ate "observation windows" by drilling openings in the posterior superior bony canal (over the antrum) (Fig. 1 0 - 5 f ) - Others advocate the use of mirrors. While these methods are acceptable and work well, the authors prefer a complete inspection that at the same time provides a solution. This is achieved by a mastoidotomy (see Chapter 7 ) , which provides direct visualization, ease of cleansing, and removal of any blocks; increases aeration; and permits irrigation of the mastoid and middle ear (Fig. 1 0 - 6 4 ) . An anti­biotic-steroid solution should flow freelv between

these two cavities. On occasion, a small strip of thin Silastic can be placed between the antrum and middle ear to ensure patency. If a wider communication is needed, a mastoidectomy and a facial recess opening could be helpful, but usually this is not the case in the types of problems discussed here. If the mastoid is found to be involved with disease, a mastoidec­tomy is done.

Once the ossicles are reconstructed, communica­tion of the middle ear and mastoid is ensured, and aeration is felt to be adequate, a thin Silastic sheeting is placed that extends from the eustachian tube to the tympanic sinus and round window niche (Fig. 10-6B). The cartilage-perichondrium graft is laid over a piece of Gelfilm, which is placed over the long process of the incus under the tympanic membrane (Fig. 10-6C) . The perichondrium that is not attached to cartilage is placed over the posterior canal wall (Fig. 10-6D) . This type of graft also is very useful in covering atticotomy defects, and in areas where re­traction pockets tend to occur or recur. It is an easy and very effective resource for ear surgery.

A slightly thicker anterior tympanic membrane remnant usuplly is present, through which a No. 1 ventilation tube can be inserted (Fig. 10—6E). The authors prefer to do this since it helps to ensure postoperative aeration and healing of the middle ear. The flap is then repositioned covering the graft, and the ear canal ss packed. If endaural or postauricular incisions were used, they are closed in layers and a dressing is applied.

Tympanoplasty for Atelectatic Tympanic Membrane (Adhesive Otitis)

Surgical Steps

1. Endaural incisions (Lempert 1 and 11). 2. Harvesting of temporal fascia. 3. Tympanomeatal flap. 4. Widening of the bony canal. 5. Elevation of the tympanic membrane. 6. Repair of ossicles.

7. Inspection of the antrum. 8. Placement of Silastic, Gelfilm, underlay fascia,

and pharyngoesophageal tube. 9. Packing and closure.

Surgical Procedures in Different Forms of Otitis Media 177

Highlights

1. Create a large tympanomeatal flap. 2. Perform a canalplasty. 3. Carefully elevate the thin tympanic membrane. 4. Section the tensor tympani tendon.

Procedure

Endaural incisions (Lempert I and II) are made. Using two-prong self-retaining retractors, temporal fascia is harvested via the Lempert II incision, placed in Ringer's solution, and pressed for two to three minutes before being used (Fig. 10-7 .4) . A tympan­omeatal flap is elevated with vertical incisions at 6 and 1 o'clock; a large flap is best since a large underlay fascia will be placed extending into the posterior canal. The posterior canal wall is widened carefully with a bur (Fig. 10-7B) . If an anterior bony overhang is present, a window shade is developed and the overhang is removed (see Chapter 8). The canal should be wide and open. This is true for all middle ear reconstructive procedures except for some cases of stapedectomy.

The thin tympanic membrane is very carefully elevated; an attempt should be made to maintain its integrity. Meticulous sectioning of adhesions is the key to this elevation. A No. 24 suction tip with the finger "off the hole" is used. The field should be as dry as possible; any bleeding is treated with cotton saturated in epinephrine solution.

The ossicular chain is inspected. Necrosis of the lenticular process often is found; if so, the area is reconstructed. If tympanosclerosis is fixating the os­sicles, this also is corrected (see Chapter 12).

Fixation of the tensor tympani tendon, including the cochleariform process, is a common finding and requires a tympanoplasty. The tendon is severed, which mobilizes the malleus and widens the meso-tympanic space (Fig. 10 -7C) . If the malleus adheres to the promontory, the adhesions are freed. If nec­essary, the distal tip of the long process of the malleus is severed after being carefully separated from the overlying tympanic membrane (Fig. 10-7D) . At this point the attic and antrum should be in­spected (as discussed in the previous procedure for an atrophic tympanic membrane).

Once the ossicles have been reconstructed and the tympanic membrane has been elevated, a piece of thin Silastic sheeting is placed extending from the eustachian tube to the tympanic sinus and round window niche (Fig. 1 0 - 7 E ) . Gelfilm that was kept in

Ringer's solution for softening is placed above the ossicles between the eustachian tube and the facial recess (Fig. 10-8/1) , and the fascia is placed beneath the thin tympanic membrane (Fig. 10-8C) . Usually a slightly thicker anterior tympanic membrane remnant is present through which a No. 1 ventilation tube can be inserted (Fig. 10-8D) . (Some surgeons thread a small piece of synthetic nonabsorbable suture through the tube and into the canal in order to avoid plugging of the tube with packing and debris. The authors have not observed plugging to be a problem in these cases.) The ventilation tube helps ensure postoperative aeration and healing of the middle ear. The ear canal is packed, the Lempert II incision is closed in two layers, and a mastoid dressing is applied.

Figure 1 0 - 9 depicts three alternative methods for improving aeration of the middle ear.

Mastoid and Tympanomastoid Procedures in Otitis Media

If intractable disease develops in the mastoid and middle ear cavity, more extensive surgical procedures are necessary. These may range from a cortical mas­toidectomy to a tympanomastoidectomy and even a radical mastoidectomy. The comments below are intended to contribute to the overall concepts of specific procedures; a complete discussion of specific indications for;these surgical alternatives is beyond the scope of this atlas.

The basic aims of mastoid surgery for chronic, medically intractable otitis media cannot be empha­sized enough. The first is the eradication of disease; the second is functional reconstruction.

Both endaural and postauricular incisions and their corresponding approaches have already been described. It should be mentioned that if a mastoid obliteration procedure is planned, a postauricular incision is made far behind (posterior to) the sulcus preparatory to the use of a muscle flap (described below). Although the authors tend to prefer post­auricular approaches for tympanomastoid surgery, the endaural approach provides easy access to the middle ear and mastoid, and is very useful in revision surgery as well. It can be limited in exposure poste­riorly in cases of large, well-pneumatized mastoid cavities.

It is useful to describe the alternative approaches in mastoid surgery. The simple mastoidectomy (which derives its name from its original use for simple drainage and not from the simplicity of the procedure) was described in Chapter 7; it involves

FIGURE 10-7.

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

FIGURE 10-8.

1

5 u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a 1 8 1

o p e n i n g t h e m a s t o i d a n d e x e n t e r a t i n g all a i r c e l l s .

T h i s a p p r o a c h c a n b e u s e d fo r p u r p o s e s o f a e r a t i o n

o r r e m o v a l o f d i s e a s e , s u c h a s i n a c u t e c o a l e s c e n t

m a s t o i d i t i s . I t d o e s n o t i n v o l v e e n t e r i n g t h e m i d d l e

e a r , e x c e p t w h e n c o m b i n e d w i t h a f ac i a l r e c e s s a p ­

p r o a c h ( p o s t e r i o r t y m p a n o t o m y ) . T h e f ac i a l r e c e s s

a p p r o a c h a l l o w s e x p l o r a t i o n o f t h e m i d d l e e a r a n d

r e m o v a l o f d i s e a s e d t i s s u e ; h o w e v e r , i t m u s t b e k e p t

i n m i n d t h a t i n c a s e s o f c h r o n i c e a r d i s e a s e t h i s

a c c e s s o f t e n i s l i m i t e d a n d r e m o v a l o f d i s e a s e d m u ­

c o s a m a y b e - i n c o m p l e t e . N e v e r t h e l e s s , t h i s c a n b e a

v e r y u s e f u l a p p r o a c h , d e p e n d i n g o n w h a t t h e s u r ­

g e o n w a n t s t o a c h i e v e i n a s p e c i f i c c a s e .

S i n c e c h r o n i c o t i t i s i n v o l v e s b o t h t h e m i d d l e e a r

a n d m a s t o i d , i t i s o f t e n n e c e s s a r y t o d i r e c t l y a p p r o a c h

b o t h c a v i t i e s ; h e n c e t h e t e r m t y m p a n o m a s t o i d e c -

t o m y . I f t h e p o s t e r i o r c a n a l w a l l i s lef t i n t a c t a n d

b o t h c a v i t i e s a r e e n t e r e d i n d e p e n d e n t l y , t h e p r o c e ­

d u r e i s t e r m e d " c a n a l w a l l u p , " " i n t a c t c a n a l w a l l

m a s t o i d e c t o m y , " o r " c l o s e d - c a v i t y t y m p a n o m a s t o i d -

e c t o m y . " I n t a c t c a n a l w a l l p r o c e d u r e s a r e p r e f e r a b l e

s i n c e t h e y p r e v e n t a n o p e n m a s t o i d c a v i t y . T h e y

s h o u l d b e p e r f o r m e d i f t h e r e i s a g o o d p o s s i b i l i t y o f

e r a d i c a t i o n o f d i s e a s e ( t h e f i r s t a i m o f m a s t o i d e c ­

t o m y ) a n d i f t h e m a s t o i d i s s u f f i c i e n t l y p n e u m a t i z e d

to a l l o w a s a f e p r o c e d u r e . A s c l e r o t i c m a s t o i d p r e ­

s e n t s a s e r i o u s r i sk o f c o m p l i c a t i o n s . I n t h e s e c a s e s ,

a t y m p a n o m a s t o i d p r o c e d u r e i s n o t r e c o m m e n d e d

u n l e s s t h e o t o l o g i s t i s e x t r e m e l y f a m i l i a r w i t h t h e

a p p r o a c h , i t s r i s k s , a n d i ts l i m i t a t i o n s . U s e o f a " c a n a l

wa l l u p " o r " c a n a l w a l l d o w n " a p p r o a c h wi l l d e p e n d

u p o n e a c h i n d i v i d u a l c a s e . T h e p r i m a r y a i m o f t h e

p r o c e d u r e i s t o e r a d i c a t e d i s e a s e , n o t t o m a i n t a i n a n

i n t a c t p o s t e r i o r c a n a l w a l l . I n o t h e r w o r d s , w h a t

s h o u l d b e d o n e i s w h a t t h e p a t i e n t n e e d s a n d n o t

w h a t t h e s u r g e o n w o u l d l ike t o d o . F o r p r a c t i c a l

p u r p o s e s , t h i s p r o c e d u r e wi l l b e d e s c r i b e d a s a n

e n d a u r a l a p p r o a c h .

P r o c e d u r e s t h a t i n v o l v e r e m o v a l o f t h e p o s t e r i o r

c a n a l w a l l a r e k n o w n a s " c a n a l w a l l d o w n " o r " o p e n -

c a v i t y " m a s t o i d e c t o m i e s . T h e y i n c l u d e t h e B o n d y

p r o c e d u r e , t h e i n t a c t - b r i d g e t y m p a n o m a s t o i d e c -

t o m y , t h e m o d i f i e d r a d i c a l m a s t o i d e c t o m y , a n d t h e

r a d i c a l m a s t o i d e c t o m y . T h e p r o c e d u r e o r i g i n a l l y d e ­

s c r i b e d b y B o n d y i s i n d i c a t e d o n l y for a n u n u s u a l

c a s e o f p r i m a r y c h o l e s t e a t o m a , a n d i n v o l v e s " e x t e r ­

i o r i z i n g " t h e c h o l e s t e a t o m a w h i l e p r e s e r v i n g t h e

i n n e r m a t r i x o r c a p s u l e . T h e p o s t e r i o r b o n y c a n a l

w a l l i s r e m o v e d , b u t t h e m i d d l e e a r c a v i t y i s n o t

e n t e r e d . T h e m o d i f i e d r a d i c a l m a s t o i d e c t o m y in­

v o l v e s e n t r a n c e i n t o t h e m i d d l e e a r c a v i t y , a l l o w i n g

t y m p a n o p l a s t y p r o c e d u r e s . T h e i n t a c t - b r i d g e t y m -

p a n o m a s t o i d e c t o m y i s a c o n t e m p o r a r y v e r s i o n o f t h e

m o d i f i e d r a d i c a l p r o c e d u r e i n w h i c h a b r i d g e o f b o n e

i s left w h e n t h e p o s t e r i o r c a n a l w a l l i s r e m o v e d ; t h i s

a l l o w s m o r e e f f e c t i v e t y m p a n o p l a s t y ( r e c o n s t r u c t i o n ;

p r o c e d u r e s . F i n a l l y , t h e r a d i c a l m a s t o i d e c t o m y i s t h e

s a m e a s a m o d i f i e d r a d i c a l m a s t o i d e c t o m y , w i t h t h e

a d d i t i o n o f r e m o v a l o f m i d d l e e a r m u c o s a a n d o s s i ­

c l e s ( e x c e p t i n g t h e s t a p e s ) , a n d c l o s u r e ( p l u g g i n g ) o f

t h e e u s t a c h i a n t u b e . T h e m a s t o i d a n d m i d d l e e a r

b e c o m e a n o p e n ( e x t e r i o r i z e d ) c a v i t y w i t h , o b v i o u s l y ,

a l o s s o f h e a r i n g

Cortical Mastoidectomy

A c o r t i c a l m a s t o i d e c t o m y w i t h o r w i t h o u t a fac ia l

r e c e s s a p p r o a c h ( p o s t e r i o r t y m p a n o t o m y ) h a s b e e n

d e s c r i b e d i n d e t a i l a n d wi l l n o t b e r e p e a t e d h e r e .

S u f f i c e i t t o m e n t i o n t h a t d r i l l i n g s h o u l d b e d o n e

c a r e f u l l y i n t h e p r e s e n c e o f d i s e a s e d t i s s u e , s i n c e

c o m p l i c a t i o n s a r e e a s i l y c a u s e d . T h e u s e o f c u r e t s t o

u n r o o f m a s t o i d c e l l s t h a t a r e full o f g r a n u l a t i o n t i s s u e

i s a g o o d a n d s a f e h a b i t , e s p e c i a l l y w h e n t h e r e a r e

d o u b t s a s t o t h e u n d e r l y i n g s t r u c t u r e s . I f i n d o u b t ,

p a l p a t e t h e a i r c e l l w i t h a W h i r l y b i r d a n d t h e n c u r e t .

S p e c i a l c o n s i d e r a t i o n s i n m a s t o i d p r o c e d u r e s a r e

d e s c r i b e d e l s e w h e r e i n t h i s c h a p t e r . F o r a n o v e r a l l

v i e w o f t h e s e c a s e s , i t i s r e c o m m e n d e d t h a t t h e e n t i r e

c h a p t e r b e r e a d , n o t j u s t i n d i v i d u a l a p p r o a c h e s .

Closed-cavity Tympanomastoidectomy

I n c i s i o n s a r e m a d e w i t h a s c a l p e l , a n d e x p o s u r e i s

i m p r o v e d b y u s i n g a c u r v e d n a s a l s p e c u l u m . T h e

first i n c i s i o n L e m p e r t 1 ) i s m a d e s e m i c i r c u m f e r e n -

t ia l ly b e t w e e n 6 a n d 1 2 o ' c l o c k o n t h e p o s t e r i o r w a l l

a t t h e b o n y c a r t i l a g i n o u s j u n c t i o n . T h e s e c o n d i n c i ­

s i o n ( L e m p e r t I I ) r u n s b e t w e e n t h e t r a g u s a n d h e l i x

a n d i n c i s u r a ; t h e e x t e n t o f t h i s i n c i s i o n d e p e n d s u p o n

t h e d e g r e e o f - ' x p o s u r e o f t h e m a s t o i d n e e d e d , b u t a

l e n g t h o f 0 . 7 5 c m i s n o t u n c o m m o n . T e m p o r a l f a sc i a

i s h a r v e s t e d t h r o u g h t h i s i n c i s i o n fo r g r a f t i n g pu r ­

p o s e s . T h e r e m a i n i n g p o s t e r i o r c a n a l s k i n ( c a r t i l a g i ­

n o u s p o r t i o n ) i s p r e s e r v e d a n d g e n t l y e l e v a t e d w i t h

a s m a l l p e r i o s t e a l e l e v a t o r , l e a v i n g t h e w h o l e p o s t e ­

r io r b o n y c a n a l c l e a r l y e x p o s e d , ( O n o c c a s i o n , a s m a l l

f ree s k i n g r a f t c a n b e r e m o v e d s a f e l y f r o m t h i s a r e a . )

T h e s p i n e o f H e n l e i s i d e n t i f i e d a n d t h e p e r i o s t e u m

e l e v a t e d o f f t h e m a s t o i d , e x p o s i n g i ts l a t e r a l s u r f a c e

( c o r t e x ) i n i t s e n t i r e t y f r o m t h e t e m p o r a l l i n e ( l i n e a

t e m p o r a l i s ) s u p e r i o r l y t o t h e m a s t o i d t ip i n t e r i o r l y

T h r e e - p r o n g s e l f - r e t a i n i n g r e t r a c t o r s a r e u s e d . I t

i s h e l p f u l t o p o s i t i o n t h e m a t r i gh t a n g l e s t o o n e

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a 183

a n o t h e r , w i t h o n e p o i n t i n g c e p h a l a d ( s u p e r i o r l y ) a n d

o n e c a u d a d ( p o s t e r i o r l y ) ( F i g . 1 0 - 1 0 / 1 ) . S c h u k n e c h t

r e t r a c t o r s a l l o w w i d e r e x p o s u r e t h a n W u l l s t e i n re ­

t r a c t o r s i n t h e s e c a s e s . A t t h i s p o i n t , t h e m a s t o i d

a n d e a r c a n a l a r e w e l l e x p o s e d .

I f n e e d e d fo r e x p o s u r e , a c a n a l p l a s t y ( p r e v i o u s l y

d e s c r i b e d ) i s d o n e , a n d t h e e n t i r e f i b r o u s a n d b o n y

a n n u l u s i s e x p o s e d w i t h o u t e n t e r i n g t h e t e m p o r o ­

m a n d i b u l a r j o i n t s p a c e .

W i t h t h e s c a l p e l , i n c i s i o n s c a n b e m a d e a t 6 a n d 1

o r 2 o ' c l o c k . T h e s e i n c i s i o n s a l l o w for e a s i e r d e v e l ­

o p m e n t o f t h e f l a p ; h o w e v e r , t h e f l a p c a n b e e l e v a t e d

w i t h o u t t h e s e i n c i s i o n s . A f t e r t h e m i d d l e e a r c a v i t y

i s e n t e r e d ( b e n e a t h t h e a n n u l u s ) , t h e a d i t u s i s e n ­

l a r g e d s o t h a t t h e i n c u s i s r e a d i l y s e e n , a l l o w i n g

i n s p e c t i o n o f t h e e p i t y m p a n u m t h r o u g h t h e a d i t u s

a d a n t r u m ( F i g . 1 0 - 1 0 B ) . T h e t e c h n i q u e o f a m a s t o i d ­

e c t o m y h a s b e e n d e s c r i b e d . C o r t i c a l w h i t e b o n e

s h o u l d b e o b t a i n e d i n all d i r e c t i o n s , b u t s a u c e r i z a t i o n

o f t h e o u t e r c o r t e x i s n o t s o i m p o r t a n t a s i n a

c o m p l e t e m a s t o i d e c t o m y s i n c e t h e r e i s n o r e s i d u a l

o p e n c a v i t y . T h e s a m e p r i n c i p l e s d e s c r i b e d fo r m a s ­

t o i d e c t o m y a s a n a p p r o a c h a p p l y h e r e . H o w e v e r ,

s o m e i m p o r t a n t p o i n t s r e l a t i v e t o c h r o n i c o t i t i s

s h o u l d b e m e n t i o n e d .

1 . I n c a s e s i n w h i c h t h e m a s t o i d i s full o f i n f l a m ­

m a t o r y t i s s u e , t h e s u r g e o n c a n e a s i l y l o s e m o m e n ­

t a r i l y t h e s e n s e o f d e p t h a n d l o c a t i o n o f t h e a n t r u m .

S i n c e t h e m i d d l e e a r i s c l e a r l y e x p o s e d , a W h i r l y b i r d

c a n b e i n t r o d u c e d i n t o t h e a n t r u m v ia t h e m i d d l e e a r

s i d e a n d v i s u a l i z e d o r p a l p a t e d t o h e l p r e g a i n s u r g i c a l

o r i e n t a t i o n .

2 . I n f l a m e d t i s s u e m u s t b e r e m o v e d c a r e f u l l y , i n

a s t e p - b y - s t e p f a s h i o n ( F i g . 1 0 - 1 0 C ) . D o n o t " p u l l "

l a r g e p i e c e s o f t i s s u e o r dr i l l i n t o " h o l e s . "

3 . S p e c i a l a t t e n t i o n s h o u l d b e g i v e n t o i d e n t i f y i n g

t h e l o c a t i o n o f t h e fac ia l n e r v e a t all l e v e l s . I t s b o n y

c a n a l m a y b e e r o d e d ( e x p o s i n g t h e n e r v e ) o r t h e

n e r v e m a y b e o u t o f i t s u s u a l a n a t o m i c p o s i t i o n , o r

b o t h .

4 . C l e a n s i n g o f all d i s e a s e d t i s s u e i n t h e a r e a o f

t h e fac ia l r e c e s s ( s u p r a p y r a m i d a l r e c e s s ) a n d t h e

t y m p a n i c s i n u s ( i n f r a p y r a m i d a l r e c e s s ) s h o u l d b e

t h o r o u g h ( F i g . 1 0 - 1 0 D ) . T h e s u r g e o n m u s t b e e s p e ­

c i a l l y c a r e f u l i n c l e a n s i n g t h i s a r e a ; t h i s i s a c o m m o n

s i t e f o r i a t r o g e n i c i n j u r y t o t h e f a c i a ! n e r v e . W i t h t h i s

s u r g i c a l a p p r o a c h , r e m o v a l o f d i s e a s e d m u c o s a i n

t h i s a r e a s o m e t i m e s i s d i f f i c u l t .

5 . O s s i c l e s s h o u l d b e c a r e f u l l y c l e a n s e d o f d i s e a s e d

m u c o s a ( F i g . 1 0 — 1 0 £ ) . I t i s c r u c i a l t o a v o i d b o t h

d i s l o c a t i o n o f t h e o s s i c u l a r c h a i n ( o r i t s r e m n a n t s )

a n d r e m o v a l o r d i s l o c a t i o n o f t h e s t a p e s , w h i c h

w o u l d h a v e o b v i o u s l y c a t a s t r o p h i c c o n s e q u e n c e s for

h e a r i n g . I f t h e s t a p e s i s a c c i d e n t a l l y r e m o v e d , t h e

o v a l w i n d o w i s s e a l e d w i t h c o l l a g e n t i s s u e a n d c o v ­

e r e d w i t h G e l f o a m s a t u r a t e d i n a n t i b i o t i c s o l u t i o n .

6 . I n s u r g e r y ( o r c h r o n i c e a r d i s e a s e , t h e s u r g e o n

s h o u l d g i v e s p e c i a l a t t e n t i o n a n d c a r e t o t h r e e a r e a s

o r s t r u c t u r e s : t h e fac ia l n e r v e , t h e h o r i z o n t a l s e m i c i r ­

c u l a r c a n a l , a n d t h e s t a p e s ( F i g . 1 0 - 1 1 ) . T h e s e a r e a s

r e q u i r e e a r l y a n d c l e a r i d e n t i f i c a t i o n d u r i n g t h e p r o ­

c e d u r e a n d v e r y c a r e f u l m a n a g e m e n t w h e n i n v o l v e d

w i t h d i s e a s e .

7 . I t i s u n w i s e t o r e m o v e t o o m u c h o f t h e a t t i c

w a l l f o r p u r p o s e s o f e x p o s u r e ; t h i s m a y r e s u l t i n a

p o t e n t i a l r e t r a c t i o n p o c k e t a r e a . I f t h i s o c c u r s , a

c a r t i l a g e - p e r i c h o n d r i u m g ra f t ( d e s c r i b e d e a r l i e r i n

t h i s c h a p t e r ) c a n b e p l a c e d t o c o v e r t h e d e f e c t .

8 . C h o l e s t e a t o m a s a n d g r a n u l a t i o n t i s s u e h a v e t h e

c a p a c i t y t o e r o d e b o n e a n d r e s u l t i n f i s tu la f o r m a t i o n .

T h e r e i s n o a g r e e m e n t a s t o t h e m a n a g e m e n t o f t h e s e

f i s t u l a e . I n g e n e r a l , w h e n a c h o l e s t e a t o m a e r o d e s t h e

p r o m o n t o r y t h e m a t r i x ( c a p s u l e ) s h o u l d b e lef t i n

p l a c e , o w i n g t o t h e h i g h f r e q u e n c y o f t o t a l h e a r i n g

l o s s a s s o c i a t e d w i t h i t s r e m o v a l . I f a f i s t u l a o f t h e

( s m a l l ) h o r i z o n t a l s e m i c i r c u l a r c a n a l e x i s t s w i t h n o

a p p a r e n t i n v o l v e m e n t o f t h e u n d e r l y i n g m e m b r a ­

n o u s l a b y r i n t h , t h e m a t r i x c a n b e r e m o v e d . V e r y

m a n y f i s t u l a e a r e i d e n t i f i e d i n s u r g e r y fo r w h i c h

t h e r e w e r e n o p r e o p e r a t i v e s y m p t o m s o r d i a g n o s t i c

s u s p i c i o n s b a s e d o n l a b o r a t o r y s t u d i e s .

9 . O n c e a g a i n , t h e p r i m a r y a i m o f t h e s e p r o c e ­

d u r e s i s t o e r a d i c a t e d i s e a s e . R e c o n s t r u c t i o n i s t h e

s e c o n d a i m a n d wi l l b e d e s c r i b e d i n C h a p t e r 1 2 .

M a i n t a i n i n g t h e p o s t e r i o r c a n a l w a l l i n t a c t i s n o t a n

a i m ; i t i s a p r e f e r e n c e i f c o n d i t i o n s a l l o w i t to be

d o n e s a f e l y a n d p r o p e r l y .

C l o s u r e a n d t h e t e c h n i q u e o f m e a t o p l a s t y h a v e

a l r e a d y b e e n d e s c r i b e d .

Intact-bridge Tympanonnstoidectomy (IBM)

T h i s p r o c e d u r e i s d e s c r i b e d h e r e a s a p o s t a u r i c u l a r

a p p r o a c h . I t s a i m s wi l l b e l i s t e d a n d t h e b a s i c s t e p s

o n l y t o u c h e d u p o n s i n c e t h e y h a v e b e e n d e s c r i b e d

e a r l i e r ( s e e C h a p * e r 5 ) . T h e s a m e p r i n c i p l e s a s f o r a

c l o s e d - c a v i t y t y m p a n o m a s t o i d e c t o m y for c h r o n i c o t i ­

t is m e d i a a p p l y t e r e . A s d i s c u s s e d p r e v i o u s l y , d i f ­

f e r e n t s k i n f l a p s c a n b e u s e d — a K o r n e r ' s f l ap o r a

f l ap m a d e b y a n i n c i s i o n i n t h e p o s t e r i o r c a n a l w a l l

s k i n a t t h e b o n y c a r t i l a g i n o u s j u n c t i o n . T h i s i n c i s i o n

c a n b e m a d e w h e n t h e p o s t a u r i c u l a r f lap i s l i f t e d , o r

t h r o u g h t h e c a n a l b e f o r e l i f t ing t h e f l a p .

184 S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

FIGURE 10-11

r

S u r g i c a l I r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a 185

Aim

T o e x t e r i o r i z e t h e d i s e a s e p r o c e s s w i t h i n t h e e p i ­

t y m p a n u m , a n t r u m , a n d m a s t o i d t o t h e m e a t u s . T h e

I B M i s a c o n t e m p o r a r y v e r s i o n o f t h e m o d i f i e d r a d i c a l

m a s t o i d e c t o m y w i t h b r i d g e p r e s e r v a t i o n , a l l o w i n g a

b e t t e r t y m p a n o p l a s t y r e p a i r .

Highlights

1 . E n l a r g e t h e a n t e r i o r c a n a l w a l l w i t h o u t o p e n i n g

t h e t e m p o r o m a n d i b u l a r j o i n t , a n d v i s u a l i z e t h e e n t i r e

f i b r o u s a n d b o n y a n n u l u s .

2 . P e r f o r m a l a r g e m e a t o p l a s t y ; t h i s i s c r u c i a l for

t h e s u c c e s s o f t h e p r o c e d u r e .

Pitfalls

1 . I n c o m p l e t e l y r e m o v i n g t h e p o s t e r i o r m e a t a l

w a l l . -

2 . P e r f o r m i n g a p o o r m e a t o p l a s t y .

Surgical Steps

1. M e a t o p l a s t y .

2 . C a n a l p l a s t y .

3 . C i r c u m f e r e n t i a l s a u c e r i z a t i o n o f t h e m a s t o i d .

4 . E n l a r g e m e n t o f t h e a d i t u s a n d s c u l p t u r i n g o f

t h e b r i d g e t o w i d e n t h e m e s o t y m p a n u m .

5 . R e m o v a l o f all d i s e a s e .

6 . P r e s e r v a t i o n , w h e n p o s s i b l e , o f t h e a n t e r i o r

t y m p a n i c m e m b r a n e a n d m a n u b r i u m .

7 . U s e o f a v e n t i l a t i o n t u b e .

8 . O s s i c u l o p l a s t y , t y m p a n o p l a s t y

9 . O b l i t e r a t i o n o f t h e a d i t u s w i t h p e r i o s t e u m o r

c a r t i l a g e .

1 0 . M a s t o i d o b l i t e r a t i o n ( u s u a l l y n o t n e c e s s a r y ) .

1 1 . T h i e r s c h g r a f t ( t h r e e t o f o u r w e e k s p o s t o p e r ­

a t i v e l y ) .

Procedure

T h i s p r o c e d u r e i n v o l v e s r e m o v a l o f t h e p o s t e r i o r

m e a t a l w a l l w i t h p r e s e r v a t i o n o f t h e " b r i d g e . "

E x p o s u r e o f t h e m a s t o i d c o r t e x w i t h a p o s t a u r i c ­

u l a r a p p r o a c h h a s a l r e a d y b e e n d e s c r i b e d . T h e t y p e

o f f l ap t o b e u s e d i s s e l e c t e d a n d a p p r o p r i a t e i n c i s i o n s

a r e m a d e ( F i g . 1 0 - 1 2 , 4 ) . T h i s i s f o l l o w e d b y a m e a ­

t o p l a s t y ( s e e C h a p t e r 7 ) a n d a c a n a l p l a s t y , u n t i l t h e

e n t i r e f i b r o u s a n d b o n y a n n u l u s i s fu l ly v i s u a l i z e d

w i t h o u t e n t e r i n g t h e t e m p o r o m a n d i b u l a r j o i n t s p a c e

( F i g . 1 0 - 1 2 B - E ) . T h i s i s t h e t i m e t o t r i m a n d

" f r e s h e n " t h e e d g e s ( i f n e c e s s a r y a n d i f p o s s i b l e ) o f

a p e r f o r a t e d t y m p a n i c m e m b r a n e .

T h e m a s t o i d w o r k i s n o w b e g u n ; F i g u r e 1 0 - 1 3 / 4

s h o w s t h e s i t e o f t h e o p e n i n g t o b e m a d e . I n t h e s e

c a s e s , t h e s u r g e o n u s u a l l y i s d e a l i n g w i t h s c l e r o t i c

s m a l l m a s t o i d s ( l a r g e , w e l l - p n e u m a t i z e d m a s t o i d s

l e n d t h e m s e l v e s b e t t e r t o i n t a c t c a n a l w a l l p r o c e ­

d u r e s ) . F i g u r e 1 0 - 1 3 B , C s h o w s t h e r e m o v a l o f d i s ­

e a s e d t i s s u e f r o m t h e m a s t o i d a n d a n t r u m . I t i s

i m p o r t a n t t o s a u c e r i z e t h e e d g e s ( F i g . 1 0 - 1 3 D ) , s i n c e

t h i s l e a d s t o a s m a l l e r c a v i t y a n d f r e q u e n t l y m a k e s i t

u n n e c e s s a r y t o o b l i t e r a t e t h e c a v i t y w i t h m u s c l e

( m a s t o i d o b l i t e r a t i o n p r o c e d u r e s a r e d e s c r i b e d b e ­

l o w ) . T h i s m a s t o i d e c t o m y i m p l i e s l e a v i n g t h e

" b r i d g e " i n t a c t ( F i g . 1 0 - 1 3 E ) . T h e b r i d g e i s t h e m o s t

m e d i a l p o r t i o n o f t h e p o s t e r o s u p e r i o r m e a t a l w a l l ,

a n d c r o s s e s t h e a t t i c t o w a r d t h e t e g m e n . I t h a s b o t h

a n t e r i o r a n d p o s t e r i o r b u t t r e s s e s . T h e a n t e r i o r b u t ­

t r e s s i s t h e s u p e r i o r p o r t i o n w h e r e t h e p o s t e r i o r b o n y

c a n a l m e e t s t h e t e g m e n ; t h e p o s t e r i o r b u t t r e s s i s t h e

i n f e r i o r p o r t i o n w h e r e t h e p o s t e r i o r b o n y c a n a l m e e t s

t h e f l o o r o f t h e e x t e r n a l a u d i t o r y c a n a l , l a t e r a l t o t h e

fac ia l n e r v e ( F i g . \0-\4A-C).

O n c e d i s e a s e d t i s s u e h a s b e e n r e m o v e d , a n o s s i c ­

u l o p l a s t y i s d o n e ; F i g u r e 1 0 - 1 4 D , E a n d F i g u r e 1 0 -

1 5 s h o w p r e p a r a t i o n fo r a n d p l a c e m e n t o f a p a r t i a l

o s s i c u l a r r e p l a c e m e n t p r o s t h e s i s ( P O R P ) . A t u b e i s

t h e n p l a c e d r i t h e t y m p a n i c m e m b r a n e , f o l l o w e d b y

a g r a f t a n d t h e o b l i t e r a t i o n o f t h e a d i t u s ( w i t h e i t h e r

p e r i o s t e u m o r c a r t i l a g e ) ( F i g . 1 0 - 1 6 ) . T h e c a v i t y ( b y

n o w t h e " o p e n " o r " e x t e r i o r i z e d " m a s t o i d c a v i t y ) i s

c o v e r e d b y t h e f l ap . A T h i e r s c h g ra f t c a n b e p l a c e d

p r i m a r i l y b u t i s u s u a l l y d o n e a f t e r s ix t o e i g h t w e e k s ,

w h e n h e a l t h y g r a n u l a t i o n t i s s u e i s c o v e r i n g t h e m a s ­

t o i d c a v i t y ( " b o w l " ) . O n o c c a s i o n , c o v e r a g e w i t h t h e

f lap a l o n e a l l o w s a d e q u a t e e p i t h e l i a l i z a t i o n o f t h e

c a v i t y , a n d s k i n g r a f t i n g ( T h i e r s c h g r a f t ) i s n o t n e c ­

e s s a r y . T h e a i m i s t o o b t a i n a w e l l - e p i t h e l i a l i z e d ,

s a f e , " e x t e r i o r i z e d " m a s t o i d c a v i t y .

Modified Radical Mastoidectomy

T h e s a m e p r i n c i p l e s o b s e r v e d i n a n i n t a c t b r i d g e

m a s t o i d e c t o m y a p p l y h e r e . I n t h i s p r o c e d u r e , h o w ­

e v e r , t h e b r i d g e i s r e m o v e d . T w o a p p r o a c h e s a r e

p o s s i b l e f o r h e m a s t o i d e c t o m y i n t h e m o d i f i e d r a d ­

ica l a p p r o a c h : ( 1 ) t h e " i n s i d e - o u t " o r a t t i c o t o m y -

a n t r o t o m y , a n d ( 2 ) t h e " o u t s i d e - i n " o r a n t r o t o m y -

a t t i c o t o m y ( s t a r t i n g f r o m t h e m a s t o i d s i d e ) . T h e l a t t e r

i s t h e a p p r o a c h t h a t h a s b e e n d e s c r i b e d p r e v i o u s l y

for m a s t o i d e t o m y — t h a t i s , d r i l l i n g i s i n i t i a t e d f r o m

t h e m a s t o i d s i d e t o w a r d t h e a n t r u m

Text continued on page 191

FIGURE 10-12 FIGURE 10-13

189

Cartilage

POAP

Surgical Procedures in Different Forms of Otitis Media

Graft

A

c

FIGURE Io-IS.

Tensortympani

Aditus

Pathology

Laleralize malleus

c

Surgical Procedures in Different Forms of Otitis Media

FIGURE 10-14.

188

KICURFC 10-16.

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a 191

I n s c l e r o t i c m a s t o i d s w i t h s c a r c e a i r c e l l s o r c e l l s

f i l l ed w i t h d i s e a s e d t i s s u e , a s a f e o u t s i d e - i n p r o c e ­

d u r e c a n b e e x t r e m e l y d i f f i cu l t . I n s u c h c a s e s , t h e

i n s i d e - o u t a p p r o a c h i s u t i l i z e d . I n t e r m s o f o r i e n t a ­

t i o n , i t i s e a s i e r t o s t a r t d r i l l i n g a t t h e e p i t y m p a n u m ,

m o v i n g i n t h e d i r e c t i o n o f t h e a n t r u m . T h i s a l l o w s

i m m e d i a t e i d e n t i f i c a t i o n o f t h e a n t r u m , t h e d o m e o f

t h e s e m i c i r c u l a r c a n a l , a n d t h e p o s i t i o n o f t h e fac ia l

n e r v e . W i t h t h e s e l a n d m a r k s u n d e r d i r e c t v i s i o n , t h e

m a s t o i d e c t o m y i s m o r e e a s i l y p e r f o r m e d , a n d t h e

p o s t e r i o r w a l l i s l o w e r e d t o t h e l e v e l o f t h e fac ia l

r i d g e . A s m e n t i o n e d e a r l i e r , t h i s a p p r o a c h i n v o l v e s

r e m o v a l o f t h e b r i d g e . I n a n i n t a c t - b r i d g e m a s t o i d e c ­

t o m y , h o w e v e r , i t m a y b e p o s s i b l e t o p a l p a t e t h e

a n t r u m w i t h a W h i r l y b i r d , i d e n t i f y t h e a n t r a l s p a c e ,

a n d dr i l l a n o p e n i n g i m m e d i a t e l y s u p e r i o r t o t h e

b r i d g e ( a s i n t h e s o - c a l l e d " o b s e r v a t i o n w i n d o w s " ) .

T h i s o p e n i n g i s c a r e f u l l y e n l a r g e d a n d a n i n s i d e - o u t

p r o c e d u r e i n i t i a t e d , t h u s l e a v i n g t h e b r i d g e i n t a c t .

T y m p a n o p l a s t y p r o c e d u r e s c a n b e p e r f o r m e d i n a

m o d i f i e d r a d i c a l m a s t o i d e c t o m y .

Radical Mastoidectomy

T h i s p r o c e d u r e i s s e l d o m p e r f o r m e d a t p r e s e n t .

E r a d i c a t i o n o f d i s e a s e c a n b e a c h i e v e d b y t h e p r o c e ­

d u r e s d e s c r i b e d a b o v e ; t h e s e i n t u r n a l l o w r e c o n ­

s t r u c t i o n , t h u s a v o i d i n g t h e h e a r i n g l o s s i n h e r e n t i n

a r a d i c a l m a s t o i d e c t o m y .

T h e a i m o f t h i s p r o c e d u r e i s t o c r e a t e a n e x t e r i o r ­

i z e d c a v i t y t h a t i n c l u d e s t h e m a s t o i d , a n t r u m , e p i ­

t y m p a n u m , a n d m e s o t y m p a n u m , l e a v i n g a d r y , e p -

i t h e l i a l i z e d c a v i t y c o n t i n u o u s w i t h t h e e x t e r n a l

m e a t u s . T h i s a p p r o a c h i s s i m i l a r t o t h e m o d i f i e d

r a d i c a l p r o c e d u r e , b u t a l s o i n v o l v e s r e m o v a l o f t h e

m u c o s a , t h e m a l l e u s , a n d t h e i n c u s w h i l e l e a v i n g t h e

s t a p e s i n t a c t . T h e e u s t a c h i a n t u b e o p e n i n g i s o b l i t e r ­

a t e d w i t h a b o n e p l u g .

The "Exteriorized" Mastoid Cavity

P o s t o p e r a t i v e c a r e o f a n o p e n ( e x t e r i o r i z e d o r

" c a n a l w a l l d o w n " ) c a v i t y i s o f t h e u t m o s t i m p o r ­

t a n c e . N o t i n f r e q u e n t l y , a s a t i s f a c t o r y p r o c e d u r e fai ls

o w i n g t o l a c k o f a d e q u a t e p o s t o p e r a t i v e l o c a l c a r e .

T h e i m p o r t a n c e o f a m e a t o p l a s t y h a s a l r e a d y b e e n

s t r e s s e d . C a r e o f t h e m a s t o i d c a v i t y i s i n i t i a t e d d u r i n g

t h e p r o c e d u r e i t s e l f b y o b t a i n i n g a n e v e n , s m o o t h

m a s t o i d b o w l ( c a v i t y ) s u r f a c e , a d e q u a t e f lap c o v e r ­

a g e , a n d p a c k i n g t h a t f a v o r s e p i t h e l i a l i z a t i o n . T h e

p r i m a r y o b j e c t i v e i s a w e l l - e p i t h e l i a l i z e d , d r y m a s t ­

o id c a v i t y . E p i t h e l i a l i z a t i o n i s a c h i e v e d b y a g e n e r ­

o u s f l ap ( w i t h f u r t h e r e p i t h e l i a l i z a t i o n ) o r b y s k i n

( T h i e r s c h ) g r a f t s d o n e d u r i n g t h e p r i m a r y p r o c e d u r e

o r s ix t o e i g h t w e e k s a f t e r s u r g e r y . O n c e e p i t h e l i a l i ­

z a t i o n i s a c h i e v e d , o p e n c a v i t i e s t e n d t o a c c u m u l a t e

e p i t h e l i a l d e b r i s a n d c e r u m e n a n d r e q u i r e c l e a n s i n g

e v e r y s i x m o n t h s t o o n e y e a r . B e c a u s e a s m a l l c a v i t y

i s d e s i r e d , a d e q u a t e s a u c e r i z a t i o n i s i m p o r t a n t . I f a

l a r g e c a v i t y i s t o b e o b t a i n e d , m a s t o i d o b l i t e r a t i o n

( d e s c r i b e d b l o w ) p r e f e r a b l y s h o u l d b e d o n e .

P a c k i n g o*' t h e c a v i t y v a r i e s a c c o r d i n g t o t h e s u r ­

g e o n ' s p r e f e r e n c e a n d e x p e r t i s e . G e l f o a m w i t h a n t i ­

b i o t i c o i n t m e n t o r s o l u t i o n c a n b e u s e d ; o t h e r su r ­

g e o n s p r e f e i a r o s e b u d p a c k f a s h i o n e d f r o m O w e n ' s

s i lk a n d c o t t o n s a t u r a t e d w i t h a n a n t i b i o t i c - s t e r o i d

s o l u t i o n . ( F r e e c o t t o n e n c o u r a g e s i n f e c t i o n a n d for ­

m a t i o n o f g r a n u l a t i o n t i s s u e . ) T h i s p a c k i n g i s a d v a n ­

t a g e o u s w h e n a t y m p a n o p l a s t y i s d o n e a n d a c e r t a i n

d e g r e e o f p r e s s u r e i s d e s i r a b l e ; t h i s i s a l s o t r u e for

a p p o s i t i o n o f t h e s k i n f l ap t o t h e w a l l o f t h e n e w l y

f o r m e d c a v i t y . T h e o u t e r o n e - t h i r d ( m e a t a l a r e a )

u s u a l l y i s p a c k e d w i t h g a u z e s a t u r a t e d w i t h a n

a n t i b i o t i c o i n t m e n t . O w e n ' s s i l k m u s t b e r e m o v e d a

m a x i m u m o f t w o w e e k s a f t e r s u r g e r y ; o t h e r w i s e i t

a d h e r e s t o t h e w a l l s o f t h e c a v i t y a n d n e c e s s i t a t e s a

n e w p r o c e d u r e t o r e m o v e i t ( s u c h a s c u r e t t i n g o r

c l e a n s i n g ) . T h e p a c k i n g u s e d i s n o t s o c r u c i a l a s t h e

r a t i o n a l e f o r s e l e c t i n g it.

T o p i c a l a n t i b i o t i c s , s t e r o i d s , a n d p r o p h y l a c t i c a n ­

t i b i o t i c s a r e u s e d r o u t i n e l y , s i n c e t h e s e p r o c e d u r e s

a r e p e r f o r m e d i n s e v e r e l y i n f e c t e d t i s s u e s . E x t e r n a l

d r e s s i n g s a r e r e m o v e d s e v e n d a y s a f t e r s u r g e r y a n d

i n n e r d r e s s i n g s a t 1 0 t o 1 4 d a y s . T h o r o u g h c l e a n s i n g

o f t h e c a v i t y i s e s s e n t i a l . R e m o v a l o r c a u t e r i z a t i o n

( o r b o t h ) o f a n y s m a l l a r e a s o f g r a n u l a t i o n t i s s u e i s

c r u c i a l . I f n e c e s s a r y , l o c a l a c i d i f i c a t i o n w i t h s o l u t i o n s

o f b o r i c a c i d p o w d e r s h o u l d b e d o n e ; a t t i m e s , d a i l y

c l e a n s i n g i s n e e d e d . T h i s m e t i c u l o u s c a r e i s e s s e n t i a l

un t i l e p i t h e l i a l i z a t i o n o c c u r s . I f s k i n g r a f t i n g i s

n e e d e d ( s e e t h e d i s c u s s i o n o f T h i e r s c h g r a f t i n g i n

C h a p t e r 7 ) , i t i s d o n e s i x t o e i g h t w e e k s a f t e r s u r g e r y .

S k i n c o v e r a g e p r e v e n t s i n f e c t i o n o f e x p o s e d a r e a s .

Mastoid Obliteration Procedure

W h e n t h e m a s t o i d c a v i t y i s s m a l l , a n o b l i t e r a t i o n

p r o c e d u r e i s n o t n e e d e d . I f a m a s t o i d o b l i t e r a t i o n

p r o c e d u r e i s n e c e s s a r y , i t u s u a l l y i s d o n e i n t h e

c o u r s e o f a t y m p a n o m a s t o i d e c t o m y . D u r i n g t h e m a s ­

t o i d e c t o m y e v e r y e f f o r t s h o u l d b e m a d e t o m a k e t h e

9 2 S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

t e s t o i d c a v i t y s m a l l . W i d e d r i l l i n g a r o u n d t h e m a s -

j i d c a v i t y h e l p s t o r e d u c e i ts s i z e .

Aim

T o m a k e t h e m a s t o i d c a v i t y s m a l l e r o r t o m i n i m i z e

c r o b l e m s a r i s i n g f r o m a l a r g e m a s t o i d c a v i t y .

I ™ L 1 . P o s t a u r i c u l a r a p p r o a c h .

L 2 . E l e v a t i o n a n d i n s e r t i o n o f a m u s c u l o f a s c i a l f lap ,

J 3 . S p l i t - t h i c k n e s s s k i n g r a f t .

I , 4 . C l o s u r e a n d p a c k i n g

i Pitfalls

I 1 . I n c o m p l e t e r e m o v a l o f u n d e r l y i n g d i s e a s e

I 2- i n f e c t i o n of t h e f l a p .

3 . R e s o r p t i o n a n d r e t r a c t i o n o f t h e g ra f t .

F 4 . S w e l l i n g o f t h e f l a p , c a u s i n g d i s r u p t i o n o f o s -

i i c l e s .

Procedure

M J e f o r e a p o s t a u r i c u l a r i n c i s i o n i s m a d e , t h e t y p e

m u s c u l a r f lap t h a t w i l l b e u s e d t o o b l i t e r a t e t h e

n a s t o i d c a v i t y s h o u l d b e d e c i d e d u p o n . T h e f l a p c a n

DE b a s e d e i t h e r s u p e r i o r l y o r i n t e r i o r l y , b u t i n g e n e r a l

i n i n f e r i o r l y p e d i c l e d f lap i s m o r e u s e f u l ( F i g . 1 0 -

1 7 / 1 ) . T h e f lap i n c l u d e s m u s c l e , f a s c i a , a n d p e r i o s ­

t e u m . B e f o r e t h e f lap i s t u r n e d i n t o t h e m a s t o i d

: a v i t y , all d i s e a s e , e s p e c i a l l y a c h o l e s t e a t o m a in t h e

: a v i t y , s h o u l d b e r e m o v e d . T h e p e d i c l e d f l ap i s

e l e v a t e d f r o m t h e b o n e , r o t a t e d , a n d i n s e r t e d i n t o

t he m a s t o i d c a v i t y ; i t c a n t h e n b e c o v e r e d w i t h

e p i t h e l i u m p r e v i o u s l y e l e v a t e d f r o m t h e m a s t o i d

c a v i t y o r t h e p o s t e r i o r c a n a l

A P a l v a ' s f l ap i s b r o a d l y b a s e d on t h e c o n c h a . A

w i d e a r e a o f t h e p o s t a u r i c u l a r m u s c u l o p e r i o s t e u m i s

i n c l u d e d i n t h i s f l a p ( F i g . 1 0 - 1 7 6 ) .

A l a r g e m e a t o p l a s t y s h o u l d b e d o n e a s pa r t o f a n

o b l i t e r a t i o n p r o c e d u r e . A l a r g e p i e c e o f c o n c h a ] ca r ­

t i l a g e i s r e m o v e d w i t h o u t t e a r i n g o r p e n e t r a t i n g t he

^Bthal s k i n ( F i g . 1 0 - 1 7 C ) . A K o r n e r ' s f lap is d e v e l -

Bffd b y m a k i n g l o n g i t u d i n a l i n c i s i o n s at 12 a n d 6

o ' c l o c k i n t h e c a n a l e x t e n d i n g o u t t o t h e a u r i c l e ( F i g .

1 0 - 1 7 D ) . T h e m e a t u s s h o u l d b e l a r g e e n o u g h t o

a d m i t t h e s u r g e o n ' s f o r e f i n g e r . T h e K o r n e r ' s f l ap i s

p l a c e d b e t w e e n t h e m u s c u l o p e r i o s t e a l f l ap a n d t h t

p a c k i n g ( F i g . 1 0 - 1 7 E ) . T h e p o s t a u r i c u l a r i n c i s i o n i *

c l o s e d a n d t h e l a t e r a l c a n a l i s p a c k e d w i t h '/2-ir*

g a u z e s t r i p s s a t u r a t e d w i t h a n t i b i o t i c o i n t m e n t . T h e

o u t e r p a c k i n g i s r e m o v e d i n o n e w e e k a n d t h e i n n e r

p a c k i n g i n t w o w e e k s

Surgery for Complications of Suppurative Otitis Media

C o m p l i c a t i o n s o f s u p p u r a t i v e o t i t i s m e d i a a r e c l a s ­

s i f i e d i n t o t w o m a j o r c a t e g o r i e s , i n f r a t e m p o r a l a n d

e x t r a t e m p o r a l . I n t r a t e m p o r a l b o n y c o m p l i c a t i o n s in­

c l u d e c o a l e s c e n t m a s t o i d i t i s , f ac ia l n e r v e p a r a l y s i s ,

p e t r o s i t i s , a n d l a b y r i n t h i t i s . E x t r a t e m p o r a l b o n y

c o m p l i c a t i o n s a r e d i v i d e d i n t o i n t r a c r a n i a l a n d e x t r a ­

c r a n i a l . I n t r a c r a n i a l c o m p l i c a t i o n s i n c l u d e e x t r a d u r a l ,

s u b d u r a l a n d c e r e b e l l a r a b s c e s s e s , m e n i n g i t i s ,

s i g m o i d s i n u s t h r o m b o p h l e b i t i s , a n d o t i t i c h y d r o ­

c e p h a l u s ; e x t r a c r a n i a l c o m p l i c a t i o n s i n c l u d e s u b p e r

i o s t e a l , p o s t a u r i c u l a r , B e z o l d ' s , a n d z y g o m a t i c ab­

s c e s s e s . O w i n g t o t h e u s e o f a n t i b i o t i c s , t h e s e

c o m p l i c a t i o n s a r e r e l a t i v e l y r a r e b u t s t i l l o c c u r . N e w

i m a g i n g t e c h n i q u e s ( C T s c a n a n d M R 1 ) h a v e r e v o l u ­

t i o n i z e d t h e t r e a t m e n t o f t h e s e c o m p l i c a t i o n s , e s p e ­

c i a l l y i n t r a c r a n i a l c o m p l i c a t i o n s . S u r g i c a l t r e a t m e n t s

p e r t i n e n t t o o t o l o g i c s u r g e o n s a r e d e s c r i b e d b e l o w .

Coalescent Mastoiditis

P a t i e n t s w i t h c o a l e s c e n t m a s t o i d i t i s a r e t r e a t e d

w i t h a c o m p l e t e m a s t o i d e c t o m y ( s e e C h a p t e r s 5 a n d

7 ) . C o m m u n i c a t i o n s h o u l d b e e s t a b l i s h e d b e t w e e n

t h e m a s t o i d a n d t h e m i d d l e e a r c a v i t y . T h e f ac i a l

r e c e s s m a y h a v e t o b e o p e n e d . A l a r g e m y r i n g o t o m y *

a n d i n s e r t i o n o f a t y m p a n o s t o m y t u b e h e l p d r a i n a g e ,

a f t e r s u r g e r y .

Facial Nerve Paralysis

F a c i a l n e r v e p a r a l y s i s m a y d e v e l o p i n a s s o c i a t i o n

w i t h a n a c u t e s u p p u r a t i v e o t i t i s m e d i a , e s p e c i a l l y i n

y o u n g e r ( p e d i a t r i c ) p a t i e n t s . A w i d e m y r i n g o t o m y i s

d o n e a n d p u s i s d r a i n e d . A l a r g e - b o r e t y m p a n o s t o m y

t u b e m a y b e i n s e r t e d a t t h e s a m e t i m e t o h e l p f u r t h e r

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

FIGURE 10-17.

194 S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

d r a i n a g e . I n t e n s i v e p a r e n t e r a l a n t i b i o t i c s a r e g i v e n ;

a f t e r s e v e r a l d o s e s , c o r t i c o s t e r o i d s a r e a d d e d . T h e

p a t i e n t i s f o l l o w e d w i t h e l e c t r o d i a g n o s t i c t e s t s . D e ­

c o m p r e s s i o n o f t h e f ac i a l n e r v e r a r e l y i s n e c e s s a r y .

O n t h e o t h e r h a n d , fac ia l p a r a l y s i s o c c u r r i n g w i t h

c h r o n i c o t i t i s m e d i a r e q u i r e s p r o m p t e x p l o r a t i o n a n d

d e c o m p r e s s i o n o f t h e n e r v e .

Petrositis

s t e p s i n c l u d e a p o s t a u r i c u l a r i n c i s i o n , a c o m p l e t e

m a s t o i d e c t o m y , e x p o s u r e o f d u r a , a n d d r a i n a g e o f

t h e a b s c e s s . T h e b o n y p l a t e o v e r t h e d u r a i s c a r e f u l l y

r e m o v e d w i t h a d i a m o n d b u r a n d c u r e t ( F i g . 1 0 -

1 9 B ) . G r a n u l a t i o n t i s s u e o v e r t h e d u r a c a n b e c a r e ­

ful ly p e e l e d o f f o r left a l o n e .

A s u b d u r a l o r b r a i n a b s c e s s i s m a n a g e d i n c o o p ­

e r a t i o n w i t h n e u r o s u r g i c a l c o l l e a g u e s . I t c a n b e

d r a i n e d t o t h e m a s t o i d c a v i t y .

P e t r o s i t i s m a n i f e s t s i t s e l f c l i n i c a l l y w i t h d e e p p a i n ,

p a l s y o f c r a n i a l n e r v e V I , a n d o t o r r h e a ( G r a d e n i g o ' s

s y n d r o m e ) . P a i n m a y b e t h e o n l y c o m p l a i n t . O n c e

t h e d i a g n o s i s i s m a d e , t h e p a t i e n t w i t h p e t r o s i t i s i s

t r e a t e d w i t h i n t e n s i v e a n t i m i c r o b i a l t h e r a p y a n d s u r ­

g e r y . A c o m p l e t e e x t e n d e d m a s t o i d e c t o m y i s d o n e ,

w i t h s p e c i a l e m p h a s i s o n l o c a t i o n a n d e x e n t e r a t i o n

o f t h e ce l l t r a c k s a r o u n d t h e s e m i c i r c u l a r c a n a l s ; i f

t h i s i s u n s u c c e s s f u l , a n a p i c e c t o m y m i g h t b e n e c e s ­

s a r y . S u r g i c a l a p p r o a c h e s t o t h e p e t r o u s a p e x m a y

b e m a d e t h r o u g h t h e s u b a r c u a t e a i r c e l l t r a c t ; t h e

[ s i n o d u r a l a n g l e ; t h e t r a c t b e n e a t h t h e p o s t e r i o r c a n a l

a n d v e r t i c a l p o r t i o n o f t h e fac ia l n e r v e ; t h e h y p o t y m -

s p a n i c c e l l s ; t h e p e r i t u b a l c e l l s t o t h e p e t r o u s a p e x

[ b e t w e e n t h e c o c h l e a a n d t h e c a r o t i d a r t e r y ; a n d t h e

m i d d l e f o s s a ( F i g . 1 0 - 1 8 ) .

Labyrinthitis

; P a t i e n t s w i t h l a b y r i n t h i t i s p r e s e n t w i t h s e n s o r i ­

n e u r a l h e a r i n g l o s s , t i n n i t u s , a n d v e r t i g o . Ini t ia l

t r e a t m e n t i n c l u d e s h o s p i t a l i z a t i o n , h y d r a t i o n , an t i ­

m i c r o b i a l t h e r a p y , a n t i v e r t i g i n o u s m e d i c a t i o n s , a n d

a m y r i n g o t o m y ; i f t h e r e i s n o i m p r o v e m e n t , s u r g i c a l

i n t e r v e n t i o n s h o u l d b e c o n s i d e r e d . A c o m p l e t e m a s ­

t o i d e c t o m y i s d o n e . T h e l a b y r i n t h c a n b e d r a i n e d

w i t h a l a b y r i n t h e c t o m v a p p r o a c h . I n t h i s p r o c e d u r e ,

t h e p o s t e r i o r a n d h o r i z o n t a l s e m i c i r c u l a r c a n a l s a r c

o p e n e d . T h e b o n y w a l l b e t w e e n t h e o v a l a n d r o u n d

w i n d o w s i s r e m o v e d , a l o n g w i t h t h e l a t e r a l e n d o f

t h e i n t e r n a l a u d i t o r y c a n a l . I n a d d i t i o n , t h e s i g m o i d

s i n u s a n d d u r a o f t h e m i d d l e a n d p o s t e r i o r c r a n i a ]

f o s s a a r e e x p o s e d t o i d e n t i f y a n d d r a i n a n y p u s i n

t h e s e a r e a s .

Intracranial Abscess

I n t r a c r a n i a l a b s c e s s e s m a y o c c u r a t a n e x t r a d u r a l

o r a s u b d u r a l s i t e , o r i n t h e b r a i n i t s e l f ( F i g . 1 0 - 1 9 / 1 ) .

IA n e x t r a d u r a l l o c a t i o n i s t h e m o s t c o m m o n .

T h e e x t r a d u r a l ( e p i d u r a l o r s u b p e r i o s t e a l ) a b s c e s s

m a y b e a t t h e m i d d l e o r p o s t e r i o r f o s s a . S u r g i c a l

Meningitis

M e n i n g i t i s i s t h e m o s t c o m m o n i n t r a c r a n i a l c o m ­

p l i c a t i o n . T h e p r i m a r y m o d e o f t r e a t m e n t i s i n t e n s i v e

a n t i m i c r o b i a l t h e r a p y ; w h e n s u r g i c a l i n t e r v e n t i o n i s

i n d i c a t e d , t h e p r o c e d u r e i s e s s e n t i a l l y t h e s a m e ar;

t h a t for a n e x t r a d u r a l a b s c e s s

Sigmoid Sinus Thrombophlebitis

S u p p u r a t i v e o t i t i s m e d i a c a n c a u s e i n f l a m m a t i o n

a r o u n d t h e s i g m o i d s i n u s , r e s u l t i n g i n a l o c a l i z e d

p h l e b i t i s . P h l e b i t i s p r o m o t e s f o r m a t i o n o f a m u r a l

t h r o m b u s , w h i c h m a y e n l a r g e , o c c l u d e t h e l u m e n ,

a n d b e c o m e i n f e c t e d . S y m p t o m s o f s i g m o i d s i n u :

t h r o m b o p h l e b i t i s i n c l u d e s p i k i n g f e v e r , c h i l l s , h e a d

a c h e , i n c r e a s e d i n t r a c r a n i a l p r e s s u r e , a n d p o s t

a u r i c u l a r e d e m a ( G r i e s i n g e r ' s s i g n )

T h e t r e a t m e n t i s a p p r o p r i a t e a n t i m i c r o b i a l t h c r a p \

a n d s u r g e r y S u r g i c a l s t e p s i n c l u d e a c o m p l e t e m a s

t o i d e c t o m v , e x p o s u r e o f t h e s i g m o i d s i n u s , n c c d U

a s p i r a t i o n o f t h e s i n u s , e v a c u a t i o n o f t h e t h r o m b u s ,

l i g a t i o n o f t h e i n t e r n a l j u g u l a r v e i n , a n d p a c k i n g a n d

c l o s u r e

A t tor a c o m p l e t e m a s t o i d s l o m v i s d o n e , t h e b o m

p l a t e o v c r l v i n g t h e s i g m o i d s i n u s i s t h i n n e d w i l l ,

d i a m o n d b u r s a n d r e m o v e d p r o x i m a l l v a n d d i s t a l l v

w i t h a c u r e t o r e l e v a t o r un t i l n o r m a ] s i n u s a p p e a r s .

A f t e r t h e s i g m o i d s i n u s i s e x p o s e d , a n e e d l e ( w i t h

s y r i n g e ) i s i n s e r t e d i n t o t h e s i n u s d i s t a l l y . I f b l o o d i s

a s p i r a t e d f r e e l y , n o f u r t h e r p r o c e d u r e i s n e c e s s a r y

a n d t h e w o u n d i s c l o s e d . I f t h e r e i s e v i d e n c e o f a

c l o t , t h e s i n u s i s o p e n e d a n d t h e t h r o m b u s i s re ­

m o v e d u n t i l b l o o d f l o w s f r e e l y ( F i g . 1 0 - 1 9 C , D ) .

P a c k i n g i m p r e g n a t e d w i t h a n t i b i o t i c s i s i n s e r t e d b e ­

t w e e n t h e w a l l o f t h e s i n u s a n d t h e o v e r l y i n g b o n y

p l a t e .

I f t h e r e i s n o r e t r o g r a d e b l e e d i n g a n d t h r o m b u s i s

s u s p e c t e d a t t h e b u l b o r i n f e r i o r l o c a t i o n , t h e i n t e r n a l

j u g u l a r v e i n i s l i g a t e d i n t h e n e c k ; t h e i n c i s i o n i s

m a d e a l o n g t h e a n t e r i o r b o r d e r o f t h e s t e r n o c l e i d o ­

m a s t o i d m u s c l e ( F i g . 1 0 - 2 0 / 1 ) . T h e m u s c l e i s r e t r a c t e d

S u r g i c a l P r o c e d u r e s i n " H f f e r e n t F o r m s o f O t i t i s M e d i a 195

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i ,

Dura

FIGURE 10-19

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i

FIGURE 10-20

1 9 8 S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

p o s t e r i o r l y , a n d t h e i n t e r n a l j u g u l a r v e i n i s i d e n t i f i e d

a n d d o u b l y l i g a t e d ( F i g . 1 0 - 2 0 8 ) . T h e v a g u s n e r v e

s h o u l d b e p o s i t i v e l y i d e n t i f i e d b e f o r e t h e v e i n i s

l i g a t e d .

T h e w o u n d i s p a r t i a l l y c l o s e d . P a c k i n g s o n t h e

s i n u s a r e r e m o v e d i n 7 t o 1 0 d a y s ; t h i s s h o u l d b e

d o n e i n t h e o p e r a t i n g r o o m o w i n g t o t h e p o s s i b i l i t y

o f b l e e d i n g .

Periauricular Abscesses

l i o n o f a t y m p a n o s t o m y t u b e w i t h o r w i t h o u a

s i m p l e m a s t o i d e c t o m y

F r e q u e n t l y t h e m a s t o i d r e t u r n s t o n o r m a l b y h e

t i m e t h e a b s c e s s i s d r a i n e d . H o w e v e r , a m a s t o i d !C-

t o m y i s h e l p f u l i n r e m o v i n g a n y r e m a i n i n g f o c u s o f

i n f e c t i o n o r u n d e r l y i n g p a t h o l o g y . A n y b l o c k a g e a t

t h e a d i t u s a d a n t r u m i s r e m o v e d . A m y r i n g o t o n y

a n d i n s e r t i o n o f a t y m p a n o s t o m y t u b e h e l p fu r t l e r

d r a i n a g e . A P e n r o s e d r a i n m a y b e i n s e r t e d i n t o t i e

a b s c e s s c a v i t y d u r i n g s u r g e r y ; i t i s a d v a n c e d g r a c 1 i -

a l ly a n d r e m o v e d i n t w o t o t h r e e d a y s .

I n f e c t i o n o f t h e m i d d l e e a r a n d m a s t o i d c a n c a u s e

a b s c e s s f o r m a t i o n a r o u n d t h e a u r i c l e . A n a b s c e s s

m a y d e v e l o p p o s t e r i o r l y ( p o s t a u r i c u l a r ) , a n t e r i o r l y

( z y g o m a t i c ) , o r i n t e r i o r l y ( B e z o l d ' s ) ( F i g . 1 0 - 2 0 C )

T h e p o s t a u r i c u l a r a b s c e s s i s t h e m o s t c o m m o n .

T r e a t m e n t i n c l u d e s a n t i m i c r o b i a l t h e r a p y a n d s u r ­

g e r y . S u r g i c a l t r e a t m e n t c o n s i s t s o f i n c i s i o n a n d

d r a i n a g e o f t h e a b s c e s s , a m y r i n g o t o m y , a n d i n s e r -

Pertinent Histopathology

F I G U R E 1 0 - 2 1

T h i s s e c t i o n s h o w s a n e p i s o d e o f a c u t e o t i t i s m e d a

w i t h p e r f o r a t i o n o f t h e t y m p a n i c m e m b r a n e . N o . e

t h a t t h e m u c o p e r i o s t e u m o v e r l y i n g t h e p r o m o n t o y

i s t h i c k e n e d .

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a 199

F I G U R E 1 0 - 2 2

T h i s s e c t i o n s h o w s a m i d d l e e a r e f f u s i o n o c c u - i s t h i c k e n e d . T h i s i s a t y p i c a l i m a g e o f m u c o i d o t i -

p y i n g t h e m i d d l e e a r c a v i t y . T h e m u c o p e r i o s t e u m t is .

202 S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

F I G U R E 1 0 - 2 5

T h i s s e c t i o n s h o w s a m a r k e d l y r e t r a c t e d , a t r o p h i c o b v i o u s l y a d i f f i c u l t t a s k t o p e r f o r m p r o p e r l y T h e

. t y m p a n i c m e m b r a n e w i t h a s o - c a l l e d " r e t r a c t i o n t h i n n e s s o f t h e m e m b r a n e j u s t i f i e s r e i n f o r c e m e n t

p o c k e t . N o t e t h e s m a l l m i d d l e e a r s p a c e a v a i l a b l e , w i t h f a s c i a d u r i n g s u r g i c a l r e p a i r ( e v e n i f t h e m e t i -

E l e v a t i o n o f t h i s m e m b r a n e w i t h o u t a n y t e a r s i s b r a n e i s e l e v a t e d i n t a c t ) .

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a 203

F I G U R E 1 0 - 2 6

T h i s s e c t i o n s h o w s a n a t e l e c t a t i c t y m p a n i c m e m ­

b r a n e a g a i n s t t h e p r o m o n t o r y . A t e l e c t a t i c o r r e t r a c t e d

m e m b r a n e s t e n d t o h a v e s m a l l a m o u n t s o f m i d d l e

e a r e f f u s i o n s . T h e " a d h e s i v e n e s s " o f t h e t y m p a n i c

m e m b r a n e a n d t h e c o m m o n f o r m a t i o n o f a d h e s i o n s

i n o t i t i s m e d i a p r o c e s s e s j u s t i f y t h e u s e o f t h i n S i l a s t i c

s h e e t s , w h i c h t e n d t o p r e c l u d e t h e s e f o r m a t i o n s ,

t h u s m a i n t a i n i n g a m i d d l e e a r s p a c e a n d t h e f r e e

m o b i l i t y o f t h e t y m p a n i c m e m b r a n e a n d o s s i c l e s .

S e c t i o n i n g o f t h e t e n s o r t y m p a n i ( w h e n t h e r e i s

f i b r o u s i n v o l v e m e n t ) a l s o a l l o w s a l a r g e r m i d d l e e a r

s p a c e a n d b e t t e r t y m p a n i c m e m b r a n e m o b i l i t y ( n o t

s h o w n i n t h i s f i g u r e ) .

!04 S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

F I G U R E 1 0 - 2 7

B e n e a t h t h e s m a l l " r e t r a c t i o n p o c k e t " l i e s a midd le -

e a r c a v i t y f i l led w i t h c o n n e c t i v e t i s s u e a n d a d i s e a s e d

m a s t o i d c o n t a i n i n g a c h o l e s t e r o l g r a n u l o m a ( C O ) a n d

o t h e r c h a n g e s . This r e q u i r e s e r a d i c a t i o n o f d i s e a s e

f r o m b o t h i h e m i d d l e c a r a n d m a s t o i d . T h e g r a d u a l

s y s t e m a t i c a p p r o a c h d e s c r i b e d i n t h i s c h a p t e r a l l o w s

t h e s u r g e o n t o d e a l w i t h t h i s c a s e p r o p c r l v . S i m p l e

i n s e r t i o n o l a t u b e o r e x p l o r a t i o n o l t h e m i d d l e c a r

no t o n l y w o u l d n o ! s u f f i c e bu t w o u l d l e a v e d i s e a s e d

m u c o p e r i o s t e u m w i t h all o f i ts p o t e n t i a l c o m p l i c a -

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a 205

F I G U R E 1 0 - 2 8

T h i s s e c t i o n s h o w s a n o t h e r c a s e o f o t i t i s m e d i a

c h r o n i c m i d d l e e a r i n v o l v e m e n t t h a t r e q u i r e s re ­

m o v a l . N e w b o n e f o r m a t i o n i n t h e c a v i t y m a k e s t h e

s u r g i c a l t a s k d i f f i c u l t , r e q u i r i n g t h e u t m o s t c a r e .

I n c o m p l e t e r e m o v a l o f d i s e a s e d t i s s u e wi l l l e a v e

d i s e a s e b e h i n d ; t o o a g g r e s s i v e a n a p p r o a c h c a n e x ­

p o s e a n d c o m p r o m i s e t h e fac ia l n e r v e , w h i c h h a s a

v e r y t h i n , b o n y c o v e r i n g l a t e r a l l y a n d i s d e h i s c e n t

t o w a r d t h e o v a l w i n d o w . T h e s t a p e s f o o t p l a t e i s

f i xed b y f i b r o u s t i s s u e . R e m o v i n g t h i s s t a p e s a n d

r e p l a c i n g i t w i t h a p r o s t h e s i s w o u l d t u r n t h i s c a s e

i n t o a s u r g i c a l t r a g e d y b e c a u s e o f t h e m i d d l e e a r

p r o c e s s i n v o l v i n g t h e v e s t i b u l e . I n c h r o n i c o t i t i s , t h e

s t a p e s f o o t p l a t e a n d t h e m a l l e u s t e n d t o b e c o m e

f ixed b y f i b r o u s t i s s u e . T h e l o n g p r o c e s s o f t h e i n c u s

a n d s t a p e s h e a d a n d c r u r a u n d e r g o r e s o r p t i o n , r e ­

s u l t i n g i n o s s i c u l a r d i s c o n t i n u i t y .

206 S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

F I G U R E 1 0 - 2 9

T h i s s e c t i o n s h o w s a m i d d l e e a r c a v i t y c o n t a i n i n g d i s s e c t i o n o f t h e c h o l e s t e a t o m a i s i m p o r t a n t s i n c e

n o t o n l y t h i c k e n e d m u c o p e r i o s t e u m b u t a l s o a c h o - fac ia l p a r a l y s i s i s a l i k e l y c o m p l i c a t i o n o f s u c h a

l e s t e a t o m a e r o d i n g i n t o t h e fac ia l n e r v e . T h i s l e s i o n , p r o c e d u r e ,

i f u n t r e a t e d , wi l l l e a d t o fac ia l p a r a l y s i s . C a r e f u l

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a 207

F I G U R E 1 0 - 3 0

T h i s s e c t i o n s h o w s a t h i c k e n e d , r e t r a c t e d t y m - m a s t o i d a n d a n t r u m a r e n o t e x p l o r e d , d i s e a s e wil l

p a n i c m e m b r a n e w i t h a d h e s i o n s ( A ) ( s p o n t a n e o u s b e i n a d v e r t e n t l y left b e h i n d a n d t h e p r o c e d u r e wil l

t y p e 111 t y m p a n o p l a s t y ) , a t h i c k m i d d l e e a r m u c o - b e i n a d e q u a t e . T h i s c a s e s h o u l d b e a p p r o a c h e d s y s -

p e r i o s t e u m (parallel arrows), a n d i n v o l v e m e n t o f t h e t e m a t i c a l l y a s d e s c r i b e d i n t h e t ex t ,

m a s t o i d w i t h a c h r o n i c i n f l a m m a t o r y p r o c e s s . I f t h e

208 S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

FIGURE 10-31

I F I G U R E S 1 0 - 3 1 , 1 0 - 3 2

I T h e s e t w o s e c t i o n s a r e f r o m a n i n d i v i d u a l w h o t e ro l g r a n u l o m a a n d g r a n u l a t i o n t i s s u e e r o d e d t h e

h a d c h r o n i c o t i t i s m e d i a b e h i n d a n i n t a c t t y m p a n i c b o n e , a n d t h e m a s s s h o w n i n F i g u r e 1 0 - 3 2 w a s f o u n d

m e m b r a n e , w i t h a l a r g e c h o l e s t e r o l g r a n u l o m a a n d i n t h e m i d d l e c r a n i a l f o s s a . T h i s w a s n o t t h e caus<:

f c f l ammatory t i s s u e (parallel arrows) o c c u p y i n g t h e o f d e a t h ,

m a s t o i d a n d a n t r u m . M E = m i d d l e e a r . T h e c h o l e s -

S u r g i c a l P r o c e d u r e s i n D i f f e r e n t F o r m s o f O t i t i s M e d i a

FIGURE 10-32.

CHAPTER 11

Exploratory Tympanotomy

T h e e x p l o r a t o r y t y m p a n o t o m y ( e x p l o r a t i o n o f t h e

m i d d l e e a r c a v i t y ) i s h i g h l i g h t e d i n t h i s c h a p t e r a s

a n e x t r e m e l y h e l p f u l a n d i n n o c u o u s d i a g n o s t i c a n d ,

o f t e n , t h e r a p e u t i c p r o c e d u r e . A s a n i n t e g r a l p a r t o f

a t y m p a n o p l a s t y , i t i s t h e r a p e u t i c ; u s e d in t h e p r e s ­

e n c e o f a n i n t a c t t y m p a n i c m e m b r a n e w h e n a d i a g ­

n o s i s o f e a r d i s e a s e i s i n d o u b t , i t i s d i a g n o s t i c . T h i s

e x p l o r a t i o n c a n b e p e r f o r m e d a s a t r a n s c a n a l p r o c e ­

d u r e ( w h e n s u s p e c t e d d i s e a s e i s l i m i t e d t o t h e m i d d l e

e a r ) o r a s a n e n d a u r a l p r o c e d u r e ( w h e n s u s p e c t e d

H i s e a s e i n v o l v e s t h e a t t i c o r m a s t o i d , o r b o t h ) . T h e

y m p a n o t o m y c a n b e d o n e u n d e r l o c a l o r g e n e r a l

ia n e s t h e s i a ( d e p e n d i n g o n t h e c a s e ) , a n d c a n b e u s e d

u n d e r m a n y d i f f e r e n t c l i n i c a l c i r c u m s t a n c e s , s u c h a s

i n c a s e s o f u n e x p l a i n e d c o n d u c t i v e h e a r i n g l o s s a n d

o c c a s i o n a l s e n s o r i n e u r a l h e a r i n g l o s s e s ( fo r e x a m p l e ,

i f t h e r e i s s u s p i c i o n o f p e r i l y m p h a t i c f i s t u l a e ) , o r

w h e n t h e p r e s e n c e o f a d h e s i o n s o r a l o c u l a t e d m i d d l e

e a r e f f u s i o n i s s u s p e c t e d . T h i s c h a p t e r d i s c u s s e s t h e

f c s e o f t h e e x p l o r a t o r y t y m p a n o t o m y for p o s s i b l e

p e r i l y m p h a t i c f i s t u l a e a n d for t y m p a n i c n e u r e c t o m y ,

H h e s e t o p i c s d o n o t fit i n t o o t h e r c h a p t e r s . T h e

e s s e n t i a l c o n c e p t i s t h a t e x p l o r a t o r y t y m p a n o t o m y ,

w h i c h c a n b e u s e d r o u t i n e l y a s a s a f e a n d s i m p l e

d i a g n o s t i c p r o c e d u r e for a v a r i e t y o f m i d d l e e a r

c o n d i t i o n s , i s a l s o p o t e n t i a l l y t h e r a p e u t i c

n i t u s , a n d a p o s i t i v e f i s t u l a t e s t , m o r e o f t e n t h a n n o t

t h e s y m p t o m s a r e i s o l a t e d a n d r e q u i r e a h i g h d e g r e e

o f s u s p i c i o n o n t h e p a r t o f t h e s u r g e o n .

F i s t u l a e c a n i n v o l v e t h e r o u n d w i n d o w o r o v a l

w i n d o w , o r b o t h , a n d a t t i m e s e v e n t h e l a t e r a l

s e m i c i r c u l a r c a n a l . T h e y c a n b e c a u s e d b y i m p l o s i v e

o r e x p l o s i v e f o r c e s ; t h u s t h e y a r e n o t e n t i t i e s b y

t h e m s e l v e s b u t m a n i f e s t a t i o n s o f a n u n d e r l y i n g o r

c a u s a t i v e p r o b l e m . F i s t u l a e c a u s e d b y g r a n u l a t i o n

t i s s u e , c h o l e s t e a t o m a , a n d o t h e r f a c t o r s c o n s t i t u t e

d i f f e r e n t c l i n i c a l e n t i t i e s f r o m t h o s e d i s c u s s e d h e r e ;

t h e y a r e d e s c r i b e d i n d i f f e r e n t c h a p t e r s a n d c a n

i n v o l v e s t r u c t u r e s o t h e r t h a n t h e o v a l a n d r o u n d

w i n d o w s .

R o u n d w i n d o w f i s t u l a e d o n o t n e c e s s a r i l y i m p l y

a f l o w o f p e r i l y m p h a s a n e s s e n t i a l e l e m e n t for t h e

d i a g n o s i s . S i n c e t h e a p p r o x i m a t e a v e r a g e v o l u m e s o f

p e r i l y m p h a n d e n d o l y m p h a r e 7 8 . 3 a n d 2 . 7 6 c u m m

r e s p e c t i v e l y , " a f ree f l o w o f p e r i l y m p h f r o m t h e

r o u n d w i n d o w " o r " a f r e e f l o w o f e n d o l y m p h a f t e r

o p e n i n g t h e e n d o l y m p h a t i c s a c " c a n o n l y b e a c ­

c o u n t e d for b y o t h e r e x p l a n a t i o n s . F r e e " f l u i d " g u s h ­

ing f r o m t h e r o u n d w i n d o w i s n o t p e r i l y m p h b u t

c e r e b r o s p i n a l f luid a n d r e q u i r e s a p a t e n t c o c h l e a r

a q u e d u c t a n d m o d i o l u s . A t t h e s a m e t i m e , w h e n t h i s

a n a t o m i c p a t h w a y i s n o t p r e s e n t t h e r e i s n o " f r e e

f l o w , " a l t h o u g h a f i s t u l a s t i l l e x i s t s

Exploratory Tympanotomy for Perilymphatic Fistula

P e r i l y m p h a t i c f i s t u l a e h a v e n o c o n s i s t e n t p a t h o g ­

n o m o n i c s i g n s . A l t h o u g h s o m e p a t i e n t s m a y h a v e

d e a r l y s u g g e s t i v e s y m p t o m s , s u c h a s h e a r i n g f luc­

t u a t i o n s a s s o c i a t e d w i t h v e s t i b u l a r d i s t u r b a n c e s , t in-

Procedure

L o c a l o r g e n e r a l a n e s t h e s i a c a n b e u s e d . E x p l o r a ­

to ry t y m p a n o t o m y f l a p s a n d e n t r a n c e i n t o t h e m i d d l e

e a r b e n e a t h t h e a n n u l u s h a v e b e e n d e s c r i b e d i n

p r e v i o u s c h a p t e r s . T h e p o s t e r i o r c a n a l i s l o w e r e d

1

w i t h c u r e t t e s i n o r d e r t o c l e a r l y v i s u a l i z e t h e r o u n d

a n d o v a l w i n d o w s . ( I f i n v o l v e m e n t o f t h e l a t e ra l

s e m i c i r c u l a r c a n a l i s s u s p e c t e d , a n e n d a u r a l a p p r o a c h

i s p r e f e r r e d . )

T h e m i d d l e e a r c a v i t y , i n c l u d i n g b o t h w i n d o w s ,

i s c o m p l e t e l y i n s p e c t e d . I t s h o u l d b e n o t e d w h e t h e r

t h e r o u n d w i n d o w m e m b r a n e i s v i s i b l e o r i n a

c o v e r e d p o s i t i o n i n t h e n i c h e . I t i s a l s o i m p o r t a n t t o

d i s t i n g u i s h t h e m e m b r a n e i t s e l f f r o m m u c o s a l f o l d s

i n t h e n i c h e ( t h e s o - c a l l e d " f a l s e m e m b r a n e " ) .

A f i s t u l a m a y b e o b v i o u s a t t h i s p o i n t ( F i g . 1 1 -

\A). I f n o t , t h e o s s i c u l a r c h a i n i s m o b i l i z e d a n d g e n t l y

E x p l o r a t o r y T y m p a n o t o m y 2 1 1

FIGURE 11-1

p a l p a t e d a n d t h e w i n d o w s a r e o b s e r v e d for l e a k s .

T h e p r e s e n c e o r a b s e n c e o f a r o u n d w i n d o w r e f l e x

( w h e n m o b i l i z i n g t h e o s s i c u l a r c h a i n ) i s t o b e n o t e d ;

i f t h e w i n d o w i s n o t v i s i b l e , a f e w d r o p s o f s a l i n e

s o l u t i o n c a n b e p l a c e d i n t h e n i c h e i n o r d e r t o o b s e r v e

s u c h a r e f l e x .

I n t h e p r e s e n c e o f o b v i o u s l e a k s o r i f t h e r e f l e x i s

a b s e n t , a p a t c h o f c o n n e c t i v e t i s s u e ( c o l l a g e n ) i s

p l a c e d o v e r t h e w i n d o w a n d r e i n f o r c e d w i t h G e l f o a m

( F i g . 1 1 - 1 B ) . ( T h e r o u n d w i n d o w m e m b r a n e i s t h r e e -

l a y e r e d , w i t h a c e n t r a l l a y e r o f c o n n e c t i v e t i s s u e . ) I n

u n c l e a r c a s e s , s m a l l p i e c e s o f G e l f o a m a r e u s e d t o

F I G U R I ; I I - 2 .

E x p l o r a t o r y T y m p a n o t o m y 213

c o v e r s u c h a r e a s s i n c e s m a l l f i s t u l a e m a y n o t b e

v i s u a l l y e v i d e n t . ( I f t h e p r o c e d u r e i s b e i n g d o n e

u n d e r l o c a l a n e s t h e s i a t h e p a t i e n t c a n b e a s k e d t o

p e r f o r m V a l s a l v a ' s m a n e u v e r . )

T h e f l a p s a r e r e p o s i t i o n e d , t h e e a r c a n a l i s p a c k e d ,

a n d a d r e s s i n g i s a p p l i e d .

Tympanic Neurectomy

A t y m p a n i c n e u r e c t o m y i m p l i e s t r a n s e c t i o n o f t h e

t y m p a n i c p l e x u s w i t h o r w i t h o u t d i v i s i o n o f t h e

c h o r d a t y m p a n i . I t i s u s e d m a i n l y f o r c a s e s o f d r o o l ­

i n g a n d c h r o n i c p a r o t i t i s . S o m e s u r g e o n s h a v e u s e d

t h i s p r o c e d u r e t o t r e a t c e r t a i n f o r m s o f a u r a l p a i n

a n d e v e n t i n n i t u s . T h e r a t i o n a l e for i t s p r i m a r y u s e s

i s f o u n d e d o n t h e p a r a s y m p a t h e t i c i n n e r v a t i o n o f

t h e s u b l i n g u a l a n d s u b m a n d i b u l a r g l a n d s ( v i a t h e

c h o r d a t y m p a n i ) a n d o f t h e p a r o t i d g l a n d ( v i a t h e

t y m p a n i c p l e x u s ) . O t h e r i n d i c a t i o n s a r e b a s e d o n t h e

m u l t i p l e s i t e s o f i n t e r c o n n e c t i o n o f t h e s e n e r v e e n d ­

i n g s w i t h o t h e r n e r v e s i n t h i s s m a l l a n a t o m i c a r e a

( w h i c h i s n o t c l e a r l y d e f i n e d ) ( F i g . 1 1 - 2 ) .

Procedure

E x p l o r a t o r y t y m p a n o t o m y f l a p s a n d e n t r a n c e o f

t h e m i d d l e e a r b e n e a t h t h e a n n u l u s h a v e a l r e a d y

b e e n d e s c r i b e d . I n i t i a l l y , t h e c h o r d a t y m p a n i i s i s o ­

l a t e d a n d a p i e c e s h a r p l y r e m o v e d . T h i s i s f o l l o w e d

b y a c a r e f u l s e a r c h o f t h e b r a n c h e s o f t h e t y m p a n i c

p l e x u s t r a v e r s i n g i n t e r i o r l y t o s u p e r i o r l y f r o m t h e

h y p o t y m p a n u m v ia t h e p r o m o n t o r y p r o m i n e n c e

( F i g . 1 1 - 3 A ) . F o r e a s i e r v i s u a l i z a t i o n , G e l f o a m p l e d g ­

e t s s a t u r a t e d w i t h e p i n e p h r i n e s o l u t i o n c a n b e a p ­

p l i e d t o t h e h y p o t y m p a n u m a n d p r o m o n t o r y ( b l o o d

v e s s e l s m a y o b s c u r e v i s u a l i z a t i o n o f t h e s e t h i n fi­

b e r s ) . Pieces o f t h e n e r v e s (a t l e a s t 3 m m i n l e n g t h )

s h o u l d b e r e m o v e d ( F i g . 1 1 - 3 B ) . I t i s i m p o r t a n t t o

r e m e m b e r t h a t s o m e n e r v e s t r a v e r s e t h e p r o m o n t o r y

t h r o u g h b o n y g r o o v e s a n d n e e d t o b e c u r e t t e d c a r e ­

ful ly . D r i l l i n g s h o u l d b e a v o i d e d . O n o c c a s i o n , a c ­

c o m p a n y i n g v e s s e l s c a n b e r e l a t i v e l y l a r g e ( fo r t h e

a r e a ) ; m i n o r l o c a l i z e d b l e e d i n g m i g h t r e q u i r e a p p l i ­

c a t i o n o f G e l f o a m s a t u r a t e d i n e p i n e p h r i n e s o l u t i o n .

I t i s a l s o i m p o r t a n t t o v i s u a l i z e t h e h y p o t y m p a n u m ;

i n a b o u t 5 0 % o f c a s e s a l a r g e r h y p o t y m p a n i c b r a n c h

i s p r e s e n t ( F i g . 1 1 - 3 C ) . T h i s b r a n c h , w h i c h s o m e ­

t i m e s h a s a n a n t e r i o r d i r e c t i o n , s h o u l d b e l o c a t e d .

T h e a r e a i s p a c k e d w i t h s m a l l p i e c e s o f c o m ­

p r e s s e d G e l f o a m , t h e f l ap i s r e p o s i t i o n e d , a n d t h e

e a r i s p a c k e d .

R e s u l t s a r e c o n s i s t e n t l y s a t i s f a c t o r y i n t h e s h o r t

t e r m , b u t a f t e r a y e a r r e i n n e r v a t i o n s e e m s t o o c c u r

i n a t least 3 0 % o f c a s e s ( u s u a l l y m o r e ) . T h e e x p l a n a ­

t i o n for t h i s , a s w e l l a s f o r t h e r e c o v e r y o f t a s t e a f t e r

s e c t i o n i n g o f t h e c h o r d a t y m p a n i , i s u n c l e a r . A

d i s c u s s i o n o f t h i s p h e n o m e n o n i s o u t s i d e t h e s c o p e

o f t h i s b o o k .

Pertinent Histopathology

F I G U R E S 1 1 - 4 T O 1 1 - 6

T h e s e t h r e e p h o t o m i c r o g r a p h s o f h o r i z o n t a l s e c ­

t i o n s o f t e m p o r a l b o n e s s h o w t h e n e r v e s o f t h e

t y m p a n i c p l e x u s ( T P ) , a c c o m p a n i e d b y t h e i r c o r r e ­

s p o n d i n g b k o d v e s s e l s ( B V ) i n b o n y c a n a l s w i t h i n

t h e p r o m o n t o r y . T h e s e a r e i m p o r t a n t a n a t o m i c f ac ­

t o r s t o b e c o n s i d e r e d for a p r o p e r n e u r e c t o m y . A d ­

d i t i o n a l l y , F i g u r e s 1 1 - 5 a n d 1 1 - 6 s h o w a t h i c k e n e d

m u c o p e r i o s t e u m o v e r l y i n g t h e p r o m o n t o r y , m a k i n g

i d e n t i f i c a t i o n o f t h e s e g r o o v e s v e r y d i f f i c u l t . T h e

s u r g e o n m u s t " p e e l " t h i s m u c o p e r i o s t e u m .

FIGURE 11-3

E x p l o r a t o r y T y m p a n o t o m y 217

FIGURE 11-6.

CHAPTER 12

Tympanoplasty

Overview

T h e a i m o f a t y m p a n o p l a s t y i s s u r g i c a l r e c o n s t r u c ­

t i o n o f t h e d a m a g e d t y m p a n o - o s s i c u l a r c h a i n . T h e

b a s i c p r i n c i p l e s i n v o l v e d a r e e r a d i c a t i o n o f d i s e a s e ,

r e c o n s t r u c t i o n o f t h e t y m p a n i c m e m b r a n e a n d t h e

s o u n d t r a n s f o r m e r m e c h a n i s m , a n d r e - e s t a b l i s h m e n l

o f a n a e r a t e d c a v i t y . I d e a l l y , t h e o p e r a t i o n s d i s c u s s e d

i n t h i s c h a p t e r a r e p e r f o r m e d s o l e l y t o r e s t o r e f u n c ­

t i o n , w i t h t h e o r i g i n a t i n g o r u n d e r l y i n g d i s e a s e w e l l

u n d e r c o n t r o l . T h e y a r e a l s o p e r f o r m e d w h e n t h e r e

a r e s e v e r a l i n d i c a t i o n s ( f o r e x a m p l e , a t y m p a n o m a s -

t o i d e c t o m y ) .

T h e s e p r o c e d u r e s i n v o l v e t h e f o l l o w i n g s t e p s :

1 . T h o r o u g h e v a l u a t i o n o f t h e s t a t u s o f t h e p a t i e n t

a n d t h e a f f e c t e d e a r a s a w h o l e .

2 . A s u r g i c a l a p p r o a c h b a s e d o n t h e p a t i e n t ' s

n e e d s .

3 . C o m p l e t e v i s u a l i z a t i o n a n d e x p l o r a t i o n o f t he

e a r .

4 . A s s e s s m e n t

5 . R e c o n s t r u c t i o n ( o n l y a f t e r s t e p s 1 t h r o u g h 4 a r e

d o n e ) .

6 . C l o s u r e a n d m e t h o d i c a l p o s t o p e r a t i v e f o l l o w -

u p .

I n o r d e r t o s u c c e e d , t y m p a n o p l a s t y m u s t b e a p ­

p r o a c h e d a s a r a t i o n a l m e t h o d o f r e c o n s t r u c t i o n a n d

n o t a s a m e r e s u r g i c a l t e c h n i q u e . T h o r o u g h k n o w l ­

e d g e o f all i n t e r d e p e n d e n t f a c t o r s a n d a v a i l a b l e a l ­

t e r n a t i v e s i s e s s e n t i a l .

E v a l u a t i o n e n t a i l s k n o w l e d g e o f t h e o r i g i n a t i n g

d i s e a s e , i t s p a t h o g e n e s i s , a n d i ts c u r r e n t s t a t u s a t

t h e t i m e o f s u r g e r y . T h e d i s e a s e c a n b e i n f l a m m a t o r y ,

t r a u m a t i c , c o n g e n i t a l , o r n e o p l a s t i c , a n d its s t a t u s

c a n b e a c t i v e , p r o g r e s s i v e , r e g r e s s i v e , l a t e n t , o r re ­

s o l v e d . I n l a r g e p a r t , t h e r e s u l t s wi l l d e p e n d u p o n

t h i s e v a l u a t i o n a n d c o n s e q u e n t d e c i s i o n s . A d e q u a t e

p l a n n i n g c a n l e a d t o a g o o d " r e c i p i e n t " e a r c o r

r e c o n s t r u c t i o n a n d a s o - c a l l e d " d r y e a r " f o r s u r g e r y .

T h i s c a n m a k e t h e p r a c t i c a l d i f f e r e n c e b e t w e e n p e r ­

f o r m i n g a t y m p a n o p l a s t y o r a t y m p a n o m a s t o i d a c -

t o m y .

I n a d d i t i o n t o t h e s t a t u s o f t h e m i d d l e e a r m u c o s a

a n d t h e u n d e r l y i n g d i s e a s e , c e r t a i n i m p o r t a n t <'ria-

t o m i c e l e m e n t s m u s t b e c o n s i d e r e d .

1 . A w i d e e a r c a n a l . (A w i d e , w e l l - a e r a t e d c . n.il

p r o v i d e s s o u n d t r a n s m i s s i o n , p r o m o t e s h e a l : i j , ,

a n d f a c i l i t a t e s c l e a n s i n g a n d i n s p e c t i o n . )

2 . A v i b r a t i n g , i n t a c t t y m p a n i c m e m b r a n e .

3 . P r o p e r l y f u n c t i o n i n g o v a l a n d r o u n d w i n d o w • .

4 . A w e l l - a e r a t e d m i d d l e e a r c a v i t y :

A . E u s t a c h i a n t u b e .

B . M a s t o i d a i r c e l l s .

C . P r o p e r m a s t o i d - m i d d l e e a r c o m m u n i c a t i o n ,

Classifications of Tympanoplasty

T h e r e a r e m a n v s y s t e m s o f c l a s s i f i c a t i o n s t h a t i n

o n e s e n s e o r a n o t h e r , c o n t r i b u t e t o a n o v e r a l l u n r e r -

s t a n d i n g o f t h e s e p r o c e d u r e s . F o r p u r p o s e s o f iri-

e n t a t i o n t w o u s e f u l o n e s a r e d e s c r i b e d h e r e , w i t h

t h e e x p e c t a t i o n t h a t t h e r e a d e r wi l l r a t i o n a l i z e t h • m

b a s e d o n h i s o r h e r o w n u n d e r s t a n d i n g o f t h e p i ib-

l e m . T h i s n e c e s s a r i l y wi l l l e a d t o a g r e e m e n t o r c h a l ­

l e n g e , a n d n o t t o a " h a v e t o l e a r n i t " a t t i t u d e .

Z o l l n e r a n d W u l l s t e i n c l a s s i f i e d t y m p a n o p l a s ' . e s

i n t o t h e f o l l o w i n g f ive t y p e s :

Type / . T h e t y m p a n i c m e m b r a n e i s p e r f o r a t e d ; I he

o s s i c u l a r c h a i n i s i n t a c t a n d m o b i l e . T h e g ra f t i s

p l a c e d a g a i n s t t h e m a l l e u s

Type 11. T h e o s s i c u l a r c h a i n i s p a r t i a l l y d e s t r o y e d ,

b u t i t s c o n t i n u i t y i s p r e s e r v e d . E i t h e r t h e m a l l e u s i s

d a m a g e d ( a n a t o m i c t y p e I I ) o r a n a t t i c o a n t r o t c r a y

T y m p a n o p l a s t y 219

h a s b e e n d o n e , a n d t h e g ra f t i s p l a c e d a g a i n s t t h e

i n c u s o r m a l l e u s , o r b o t h ( p h y s i o l o g i c t y p e I I ) .

Type 111. T h e m a l l e u s a n d i n c u s a r e m i s s i n g , a n d

t h e r e i s a n i n t a c t a n d m o b i l e s t a p e s . T h e g ra f t i s

p l a c e d a g a i n s t t h e s t a p e s .

Type IV. T h e m a l l e u s , i n c u s , h e a d , a n d c r u r a o f

t h e s t a p e s a r e m i s s i n g . T h e r e i s a m o b i l e f o o t p l a t e .

T h e g r a f t i s p l a c e d a g a i n s t t h e f o o t p l a t e .

Type V. T h i s i s s i m i l a r to t y p e I V , b u t t h e r e i s a

f i x e d f o o t p l a t e . T h e h o r i z o n t a l s e m i c i r c u l a r c a n a l i s

f e n e s t r a t e d , a n d t h e g ra f t i s p l a c e d a g a i n s t i t a n d t h e

f i x e d f o o t p l a t e . P a p a r e l l a d i f f e r e n t i a t e s b e t w e e n

t y p e s V o , w h i c h r e f e r s t o t h e c l a s s i c t y p e d e s c r i b e d ,

a n d V ( j , w h i c h r e f e r s t o a p u r p o s e f u l , c o m p l e t e

s t a p e d e c t o m y i n s e l e c t e d c a s e s , w i t h t h e g r a f t i n v a -

g i n a t e d i n t o t h e o p e n w i n d o w .

F a r r i o r c l a s s i f i e d t y m p a n o p l a s t y a c c o r d i n g t o t h e

b a s i c p a t h o l o g i c a n a t o m y a t t h e c o m p l e t i o n o f t h e

s u r g e r y . H e i d e n t i f i e d t h e f o l l o w i n g t y p e s :

. Type I . T y m p a n i c m e m b r a n e r e c o n s t r u c t i o n w i t h

a n i n t a c t o s s i c u l a r c h a i n .

Type II. R e c o n s t r u c t i o n o f a n e w t y m p a n i c m e m ­

b r a n e i n i ts n a t u r a l p o s i t i o n .

Type III. R e c o n s t r u c t i o n o f a n e w t y m p a n i c m e m ­

b r a n e o n t o p o f a m o b i l e s t a p e s . T h i s i s d i v i d e d i n t o

t h e f o l l o w i n g s u b c a t e g o r i e s :

I I I — C l a s s i c .

I l l I G — I n c u s g r a f t .

I l l 1 G M — I n c u s g r a f t t o m a l l e u s .

I l l M G — M a l l e u s h e a d g ra f t .

III B G — B o n e g r a f t .

H I P O R P — P a r t i a l o s s i c u l a r r e p l a c e m e n t p r o s ­

t h e s i s .

Type IV. R e c o n s t r u c t i o n o f a n e w t y m p a n i c m e m ­

b r a n e a n d c o l u m e l l a o r f o o t p l a t e o f s t a p e s . T h i s i s

d i v i d e d i n t o t h e f o l l o w i n g s u b c a t e g o r i e s :

I V — C l a s s i c .

I V I G — I n c u s g ra f t

I V M G — M a l l e u s g ra f t .

I V B G — B o n e g r a f t .

I V C G — C a r t i l a g e g r a f t .

I V T O R P — T o t a l o s s i c u l a r r e p l a c e m e n t p r o s ­

t h e s i s .

Type V . R e c o n s t r u c t i o n o f t h e t y m p a n i c m e m ­

b r a n e , e i t h e r o v e r a f i s t u l a i n t h e h o r i z o n t a l s e m i c i r ­

c u l a r c a n a l o r w i t h s e c o n d a r y f e n e s t r a t i o n o f t h e

h o r i z o n t a l s e m i c i r c u l a r c a n a l .

P r o c e d u r e s t o b e p e r f o r m e d , e i t h e r a l o n e o r i n

c o m b i n a t i o n , i n c l u d e t h e f o l l o w i n g :

1 . T y m p a n i c m e m b r a n e s — m y r i n g o p l a s t y / t y m p a ­

n o p l a s t y .

2 . O s s i c u l a r c h a i n — t y m p a n o p l a s t y / o s s i c u l o p l a s t y .

3 . L a b y r i n t h i n e w i n d o w s — t y m p a n o p l a s t y w i t h

s t a p e d e c t o m y

4 . A e r a t i o n f a c t o r s — e u s t a c h i a n t u b e ( P E t u b e ) ,

m a s t o i d a i r c e l l s , m a s t o i d m i d d l e e a r c o m m u n i c a t i o n

( m a s t o i d o t o m y / m a s t o i d e c t o m y ) .

5 . T y m p a n o m a s t o i d c a v i t y — t y m p a n o m a s t o i d e c -

t o m y .

A n u m b e r o f g r a f t s a n d m a t e r i a l s c a n b e u s e d i n

a t y m p a n o p l a s t y . F o r t h e p u r p o s e s o f a n o v e r a l l

c o n c e p t , s o m e b a s i c a s p e c t s a r e d e s c r i b e d h e r e .

K n o w l e d g e o f t h e s e e l e m e n t s i s e s s e n t i a l a n d f u r t h e r

s t u d y i s r e c o m m e n d e d , e s p e c i a l l y i n t h e s e d a y s w h e n

t h e s u r g e o n m u s t " s w i m i n a s e a o f g a d g e t s . " I t i s

o f p a r a m o u n t i m p o r t a n c e t o r e m e m b e r a t all t i m e s

t h a t t h e s u r g e o n i s r e s p o n s i b l e t o t h e p a t i e n t . M a n ­

u f a c t u r e r s ( n o m a t t e r h o w d e d i c a t e d a n d e t h i c a l ) a r e

r e s p o n s i b l e t o a b o a r d o f d i r e c t o r s a n d u l t i m a t e l y t o

t h e s t o c k h o l d e r s . A l t h o u g h i t i s e s s e n t i a l t o w o r k

s i d e b y s i d e w i t h i n d u s t r y f o r t h e g o o d o f t h e p a t i e n t ,

t h e d e c i s i o n o f w h a t t o u s e a n d h o w t o u s e i t b e l o n g s

t o t h e s u r g e o n .

Grafts

G r a f t s a r e c l a s s i f i e d b y t h e r e l a t i o n s h i p b e t w e e n

t h e d o n o r a n d t h e r e c i p i e n t i n t o t h e f o l l o w i n g c a t e ­

g o r i e s :

1 . A u t o g r a f t ( a d j e c t i v e , a u t o l o g o u s ) . D o n o r a n d

r e c i p i e n t a r e o f t h e s a m e o r g a n i s m .

2 . l s o g r a f t ( i s o g e n e i c ) . D o n o r a n d r e c i p i e n t a r e

t w i n s ( w i t h t h e s a m e g e n o t y p e ) .

3 . A l l o g r a f t o r h o m o g r a f t ( a l l o g e n e i c , h o m o l o ­

g o u s ) . D o n o r a n d r e c i p i e n t h a v e d i f f e r e n t g e n o t y p e s .

4 . X e n o g r a f t o r h e t e r o g r a f t ( x e n o g e n e i c , h e t e r o l ­

o g o u s ) . D o n o r a n d r e c i p i e n t a r e d i f f e r e n t s p e c i e s .

I n a d d i t i o n t o t i s s u e s , o t h e r s o u r c e s a n d m a t e r i a l s

a r e a v a i l a b l e . T h e y i n c l u d e p l a s t i c , m e t a l s , a n d c e ­

r a m i c s ( a l l o p l a s t i c m a t e r i a l s ) ; a n d d e n a t u r e d a n i m a l

s k i n g e l a t i n , f i lm ( G e l f i l m ) , a n d s p o n g e ( G e l f o a m ) .

I n o r d e r t o a c h i e v e a s a f e , l o n g - t e r m g r a f t , a d d i t i o n a l

c r i t e r i a m u s t b e c o n s i d e r e d .

1 . B i o c o m p a t i b i l i t y — t h e r e a c t i o n o f t h e i m p l a n t i n

t h e b o d y ( s u c h a s p r e s e n c e o r a b s e n c e o f c y t o t o x i c ­

i t y ) , a n d i n f l u e n c e o f t h e b o d y o n t h e i m p l a n t ( fo r

e x a m p l e , d e g r a d a t i o n ) .

2 . B i o f u n c t i o n a l i t y — s y m b i o s i s o f t h e i m p l a n t w i t h

t h e i m p l a n t s i t e .

I n t e r m s o f i t s i n t e r a c t i o n w i t h t h e b o d y , a m a t e r i a l

c a n b e :

1 . B i o i n e r t — n o r e a c t i o n o f t h e s u r f a c e t o t h e b o d y

(a t m o s t a s m a l l , f i b r o u s c a p s u l e i s s e e n ) .

2 . B i o t o l e r a n t — g o o d c a p s u l e a r o u n d i t w i t h o u t

s i g n s o f m a r k e d c e l l u l a r a c t i v i t y ( s u c h a s g i a n t c e l l s )

3 . B i o a c t i v e — b o n d i n g o f t h e m a t e r i a l w i t h t h e

s u r r o u n d i n g t i s s u e .

220 T y m p a n o p l a s t y

Grafting of the Tympanic Membrane

T h e t y m p a n i c m e m b r a n e h a s t h r e e l a y e r s : ( 1 ) a n

o u t e r ( l a t e r a l ) s t r a t i f i e d s q u a m o u s e p i t h e l i u m ( c o n t i n ­

u o u s w i t h t h a t o f t h e e a r c a n a l ) ; ( 2 ) a m i d d l e c o n n e c ­

t ive t i s s u e c o r e c o n t a i n i n g c o l l a g e n a n d e l a s t i c f i be r s

( p l u s t h e v a s c u l a r e l e m e n t s ) ; a n d ( 3 ) a n i n n e r l a y e r

( c o n t i n u o u s w i t h t h a t o f t h e m i d d l e e a r m u c o p e r i o s ­

t e u m ) .

P e r f o r a t i o n s t h a t h e a l s p o n t a n e o u s l y t e n d t o e x ­

c l u d e t h e c o n n e c t i v e t i s s u e l a y e r ( m o n o m e r i c m e m ­

b r a n e ) . T h o s e m e m b r a n e s t h a t d o n o t h e a l t e n d t o

h a v e i n g r o w t h o f t h e o u t e r s q u a m o u s e p i t h e l i u m

c o v e r i n g t h e e d g e s o f t h e p e r f o r a t i o n . T h e a i m o f

g r a f t i n g i s a t r u l y a n a t o m i c r e c o n s t r u c t i o n . T h e c o l ­

l a g e n l a y e r p l a c e d a s a g r a f t r e i n s t a t e s t h e m i d d l e

l a y e r , a l l o w s e p i t h e l i a l c e l l s t o m i g r a t e , r e - e s t a b l i s h e s

c o n t i n u i t y , a n d p e r m i t s t h e m e m b r a n e t o r e c o v e r i ts

v i b r a t o r y c h a r a c t e r i s t i c s . T h i s s u p p o r t s t h e c o n c e p t s

o f r e i n f o r c i n g m o n o m e r i c m e m b r a n e s a n d p e e l i n g

t h e e d g e s o f a p e r f o r a t i o n b e f o r e g r a f t i n g .

Tissues and Materials

Skin. S k i n i s v e r y u s e f u l for c o v e r i n g r a w a r e a s i n

m a s t o i d b o w l s a n d m e a t o p l a s t y . I t a l s o p r o v i d e s

c o v e r a g e a n d , a t t i m e s , v a s c u l a r i t y (in p e d i c l e d

g r a f t s ) o v e r c o l l a g e n g r a f t s ; t h i s g i v e s a d d i t i o n a l

t h i c k n e s s a n d , m o r e i m p o r t a n t l y , p r o t e c t s t h e graf t

f r o m i n f e c t i o n a n d g r a n u l a t i o n t i s s u e . I t m u s t b e

r e m e m b e r e d t h a t a f ree c o l l a g e n gra f t ( fo r e x a m p l e ,

f a s c i a ) h a s n o b l o o d s u p p l y o f i t s o w n ( w h e n o r ig i ­

n a l l y p l a c e d ) , a n d i s an e a s y p r e y for i n l c c t i o n .inc.1

g r a n u l a t i o n t i s s u e . A s u s e f u l a s s k i n m a v b e , h o u -

e v e r , i t d o e s n o t r e p l a c e c o l l a g e n g r a f t s . P l a c e d b v

i t s e l f a s s o l e c o v e r a g e o f a p e r f o r a t i o n , i t i s d o o m e d

t o f a i l u r e . S k i n c a n b e o b t a i n e d a s a s p l i t - t h i c k n e s s

g ra f t ( 0 . 0 0 3 t o 0 . 0 0 4 c m ) f r o m a n o n - h a i r - b e a r i n g

a r e a f r o m t h e u p p e r a r m , f o r e a r m , t h i g h , o r a b d o ­

m e n , b y u s i n g a d e r m a t o m e ( D a S i l v a - D o v a l - S i l v e r )

o r a p l a i n r a z o r b l a d e o n a s t r a i g h t c l a m p ( F i g . 1 2 -

M ) . I t c a n a l s o b e a f u l l - t h i c k n e s s g ra f t f r o m the

p o s t a u r i c u l a r r e g i o n ( F i g . 1 2 - 1 8 ) o r t h e p o s t e r i o r

c a n a l s k i n ( fo r e x a m p l e , v i a a L e m p e r t 11 i n c i s i o n

[ F i g . 1 2 - 1 C ] ) , o r f r o m t h e m e d i a l c a n a l s k i n a s a f ree

o r p e d i c l e d g ra f t . P e d i c l e d s k i n g r a f t s h a v e t h e d i s ­

a d v a n t a g e o f b e i n g t h i c k a n d c u m b e r s o m e t o w o r k

w i t h , b u t t h e y h a v e t h e i r o w n b l o o d s u p p l y

Collagen. S o u r c e s o f c o l l a g e n a r e m a i n l y t h e f a sc i a ,

t h e p e r i c h o n d r i u m , a n d t h e v e i n s . T h e m o s t c c t n -

m o n l y u s e d f a s c i a i s t h e t e m p o r a l , w h i c h i s a v a i l a b l e

v i a t h e s a m e a p p r o a c h i n c i s i o n o r a s m a l l s e p a r a t e

i n c i s i o n , b u t i n t h e s a m e o p e r a t i v e f ie ld ( F i g . 1 2 - 1 D ,

E ) . I t i s i m p o r t a n t t o o b t a i n f a s c i a p r o p e r a n d n o t t h e

l a y e r o f a e r o l a r c o n n e c t i v e t i s s u e o v e r l y i n g it , t h e s o -

c a l l e d " f o o l ' s f a s c i a " ( t h e l a t t e r a l s o h a s c o l l a g e n a n d

c a n b e u s e d fo r g r a f t i n g ) . P e r i c h o n d r i u m c a n a l s o b e

o b t a i n e d e a s i l y f r o m t h e t r a g u s a s s u c h , o r a s a

c a r t i l a g e - p e r i c h o n d r i u m g ra f t ( s e e C h a p t e r 1 0 ) . I t ct .n

a l s o c o m e f r o m c o n c h a l c a r t i l a g e .

A v e i n f r o m t h e d o r s u m o f t h e h a n d a l s o i s e a s i l y

o b t a i n a b l e ( s e e C h a p t e r 1 3 ) . I n a d d i t i o n , a l l o g e n e i c

( h o m o l o g o u s ) p e r i c h o n d r i u m f r o m t h e t i b i a , s e p t u m ,

c o s t o c h o n d r a l c a r t i l a g e , a n d s o o n c a n b e u s e d , a s

w e l l a s a l l o g e n e i c d u r a m a t e r , a m n i o t i c m e m b r a n ; ,

a n d c o r n e a . T h e a u t h o r s h a v e n o e x p e r i e n c e w i t h

t h e l a s t t h r e e ; r e p o r t s o n t h e i r u s e , a s w e l l a s c n

o t h e r t i s s u e s ( s u c h a s h e a r t v a l v e s ) , a r e n o t d e f i n i t i v e .

A l l o g e n e i c t y m p a n i c m e m b r a n e g r a f t s a r e v e r y

s u c c e s s f u l ( u n d e r t h e p r o p e r c i r c u m s t a n c e s ) , a n d

r e p r e s e n t a g o o d a n a t o m i c a n d f u n c t i o n a l a l t e r n a t i v e .

A l o n g - t e r m d r a w b a c k i s t h a t o f v i r u s e s l i v i n g i n

d o n o r t i s s u e ; t h i s m i g h t c o m p r o m i s e t h e u s e c f

a l l o g e n e i c g r a f t s i n t h e f u t u r e .

T h e i d e a l g r a f t m a t e r i a l w o u l d b e p u r e c o l l a g e i

a n d e l a s t i c f i b e r s c a p a b l e o f p r o v i d i n g t h e m i d d l e

l a y e r , b e c o m i n g i n c o r p o r a t e d t o t h e m e m b r a n e , a d

a l l o w i n g a n d f a v o r i n g e p i t h e l i a l m i g r a t i o n .

X e n o g e n e i c ( h e t e r o l o g o u s ) m a t e r i a l s , s u c h a s b i -

v i n e d u r a m a t e r , a r e c u r r e n t l y b e i n g e v a l u a t e d S y

s o m e g r o u p s a n d , i f s u c c e s s f u l , c o u l d e v e n t u a l v

b e c o m e a v a i l a b l e .

Grafting of the Ossicular Chain

I h o s e t h r e e i n l c r l o c k c d o s s i c l e s ( u n d e r t h e p r o t e \ -

l i v e i n f l u e n c e o l I w o m i d d l e e a r m u s c l e s ) , w h i c i

t r a n s m i t s o u n d w a v e s a s a u n i t f r o m t h e t v m p a m :

m e m b r a n e t o t h e o v a l w i n d o w , c a n b e p a r t l y t :

t o t a l l y f i x a t e d , d i s l o c a t e d , o r d e s t r o y e d . T h e p u r p o s 1

o f g r a f t i n g i s t o r e - e s t a b l i s h f u n c t i o n a l c o n t i n u i t / -

f r o m t h e t y m p a n i c m e m b r a n e t o t h e o v a l w i n d o v

I d e a l l y , g r a f t s a n d m a t e r i a l s s h o u l d b e e a s i l y p o s

t i o n e d a n d s h a p e d ; b e r e a d i l y a v a i l a b l e ; c a u s e m i n i

ma l t i s s u e r e a c t i o n ; r e m a i n s t a b l e w i t h i n f e c t i o n ; a n c

r e m a i n i n p o s i t i o n , n o t e x t r u d i n g o r d a m a g i n g t h -

t y m p a n i c m e m b r a n e . C o m m o n c o m p l i c a t i o n s in­

c l u d e r e s o r p t i o n , r e j e c t i o n , f i x a t i o n , d i s p l a c e m e n t ,

a n d e x t r u s i o n . A b r i e f o v e r a l l a s s e s s m e n t f o l l o w s ; a

c o m p r e h e n s i v e d e s c r i p t i o n i s o u t s i d e t h e s c o p e o '

t h i s b o o k .

FIGURE 12-1

222 T y m p a n o p l a s t y

Tissues and Materials

Ossicles and Cortical Bone. O s s i c u l a r a n d c o r t i c a l

b o n e ( a u t o l o g o u s o r a l l o g e n e i c ) g r a f t s a r e a v a i l a b l e ,

a r e e a s i l y s c u l p t u r e d , a r e t h e b e s t t o l e r a t e d , a n d a r e

l e a s t l i k e l y t o e x t r u d e . T h e i r d r a w b a c k s i n c l u d e d i s ­

p l a c e m e n t , r e f i x a t i o n , a n d a t e n d e n c y t o a d h e r e t o

t h e m a r g i n s o f t h e o v a l w i n d o w , t o e x t r u d e o r

d i s p l a c e i f t h e r e i s n o m a l l e u s ( t h e l a t t e r i s c o m m o n

t o all p r o s t h e s e s ) , a n d t o a t r o p h y .

Cartilage. C a r t i l a g e ( a u t o l o g o u s o r a l l o g e n e i c )

g r a f t s a r e a v a i l a b l e , a r e e a s i l y s h a p e d a n d w e l l tol­

e r a t e d , a n d s h o w v e r y l i t t l e e x t r u s i o n . H o w e v e r ,

c a r t i l a g e l a c k s s t i f f n e s s , w o r k i n g w e l l a t t h e o n s e t

b u t t e n d i n g t o l o s e r i g i d i t y a n d " f a l l a p a r t " a f t e r a

f e w y e a r s ( t h i s i s s u p p o r t e d b y s o m e r e p o r t s b u t

d e n i e d b y o t h e r s ) . I n a d d i t i o n , c a r t i l a g e t o l e r a t e s

i n f e c t i o n p o o r l y .

Plastics. T e f l o n is u s e d p r i m a r i l y as a p i s t o n for a

s t a p e d e c t o m y . A l t h o u g h t h i s s o l i d p l a s t i c h a s s m o o t h

s u r f a c e s , i t h a s n o l o n g - t e r m i n f l a m m a t o r y r e a c t i o n

A n e x c e l l e n t m a t e r i a l w h e n p r o p e r l y u s e d , i t i s n o t

e f f i c i e n t a s a T O R P ( t o t a l o s s i c u l a r r e p l a c e m e n t p r o s ­

t h e s i s ) . T e f l o n i s a g o o d m a t e r i a l for P E t u b e s .

P l a s t i p o r e ( h i g h - d e n s i t y p o l y e t h y l e n e ) , w h i c h h a s

b e e n u s e d i n T O R P s a n d P O R P s , i s s t i l l a s u b j e c t o f

c o n t r o v e r s y . I t s i n i t i a l l y i m p r e s s i v e s u c c e s s w a s fol­

l o w e d b y a n e q u a l l y u n i m p r e s s i v e a n d d i s a p p o i n t i n g

f a i l u r e i n t e r m s o f e x t r u s i o n r a t e . P l a s t i p o r e i s e a s i l v

a v a i l a b l e ; i s n o t s o r ig id a s o s s i c l e s o r c e r a m i c s ; c a n

b e e a s i l y s h a p e d a c c o r d i n g t o n e e d ; i s h i o m e c h a n i -

c a l l y s o u n d ; i s r e l a t i v e l y e a s y t o p o s i t i o n a n d s t e r i l i z e

( t h i s r e q u i r e s sk i l l t o d o p r o p e r l y ) ; d o e s n o t a d h e r e

t o t h e m a r g i n s o f t h e o v a l w i n d o w - ; a n d i s a n e f f i c i e n t

s o u n d c o n d u c t o r . I t s d r a w b a c k s a r e t h a t i t c a u s e s a

f o r e i g n b o d y r e a c t i o n i n t h e m i d d l e e a r , a n d c a n

e x t r u d e a n d s l i p . T h e h i g h e x t r u s i o n r a t e i s s ign i f i ­

c a n t l y d i m i n i s h e d b y p l a c i n g c a r t i l a g e o v e r t h e p r o s ­

t h e s i s ( b e n e a t h t h e t y m p a n i c m e m b r a n e o r t y m p a n i c

m e m b r a n e g r a f t , i d e a l l y u n d e r t h e m a l l e u s ) . S l i p p a g e

a t t h e o v a l w i n d o w ( w h e n p l a c e d o v e r i n t a c t , m o b i l e

f o o t p l a t e s ) c a n b e r e d u c e d b y c r e a t i n g a s m a l l o p e n ­

i n g i n t h e f o o t p l a t e , t h r o u g h w h i c h a T O R P w i t h a

p e g i n i ts d i s t a l e n d i s i n s e r t e d ( d e s c r i b e d b e l o w ) .

P O R P s c a n b e s t a b i l i z e d b y m a k i n g a s l i t t h a t a l l o w s

a m o r e s t a b l e c o n t a c t w i t h t h e s t a p e s h e a d . I n s p i t e

o f t h e s e d r a w b a c k s , T O R P s a n d P O R P s m a d e o f

P l a s t i p o r e w o r k v e r y w e l l i n p r o p e r l y s e l e c t e d c a s e s

a n d r e m a i n a f irst c h o i c e u n d e r t h e p r o p e r c o n d i ­

t i o n s .

Ceramics. C e r a m i c s , i n o r g a n i c c r y s t a l m a t e r i a l s

p r o d u c e d a t h i g h t e m p e r a t u r e s , a r e t h e " i n " m a t e ­

r ia l s i n o s s i c u l o p l a s t y a n d r e c o n s t r u c t i v e e a r s u r g e r y

T h e y h a v e b e e n u s e d s u c c e s s f u l l y i n o r t h o p e d i c s a n d

d e n t i s t r y . G l a s s - c e r a m i c s a r e p r o d u c e d b y t h e r m illy

t r e a t i n g g l a s s , o b t a i n i n g a p o l y c r y s t a l l i n e m i c r o s t j u c -

t u r e . T h e a d v a n t a g e s o f t h e s e d e n s e m a t e r i a l s are

t h a t t h e y a r e b i o c o m p a t i b l e , b i o f u n c t i o n a l , e a s y t o

p l a c e a n d m a n i p u l a t e , a n d , r e p o r t e d l y , e a s y t o

s h a p e . T h e a u t h o r s h a v e f o u n d , h o w e v e r , t h a t t l e y

a r e h a r d t o r e s h a p e a n d s o m e t i m e s b r e a k , e v e n w l e n

s h a p e d w i t h a d i a m o n d dr i l l u n d e r c o n s t a n t i r r iga ­

t i o n . A l t h o u g h p r o m i s i n g , t h e s e m a t e r i a l s h a v e still

t o w i t h s t a n d t h e t e s t o f t i m e i n o t o l o g y . E v i d e n c e

s u g g e s t s t h a t t h e y p r o b a b l y w i l l ; t i m e a n d e x p e r i e n c e

s h o u l d tel l u s ( n o t t h e m a n u f a c t u r e r s ) . I n p r o s t h e t i c s ,

t h e m o s t c o m m o n l y u s e d c e r a m i c i s t h e b i o a c t i v e ,

p o r o u s , c r y s t a l l i n e f o r m o f c a l c i u m p h o s p h a t e . B i o -

g l a s s i s a n e x a m p l e o f g l a s s a n d c e r a v i t a l , a f o r m o f

c a l c i u m p h o s p h a t e w i t h t h e s a m e c a l c i u m - t o - p h c s -

p h a t e r a t i o a s t h e n a t u r a l b o n e m i n e r a l h y d r o x y -

a p a t i t e , w h i c h i s p e r h a p s t h e m o s t b i o c o m p a t i b l e

m a t e r i a l a v a i l a b l e . T h e e s s e n t i a l a i m i n p r o s t h e t i c s i s

t o o b t a i n m a t e r i a l s t h a t a r e a s c l o s e t o n a t u r a l i s

p o s s i b l e , fu l f i l l i ng t h e c o n c e p t o f " r e p l a c i n g w j h

s a m e . "

Plastics. S i l a s t i c i s c o m m o n l y u s e d i n m i d d l e e i r

s u r g e r y a s t h i n s h e e t s a n d a s P E t u b e s . I t i s b i o i n e r i

( t h a t i s , i t e l i c i t s n o l o n g - t e r m i n f l a m m a t o r y r e a c t i o n ) ;

i ts u s e s a r e ( 1 ) t o p r e v e n t a d h e s i o n s w h e n p l a c e d

o v e r r o u g h , l a c e r a t e d s u r f a c e s o r s u r r o u n d i n g

p r o s t h e s e s o r g r a f t s , t h u s a l l o w i n g a n a e r a t e d o p e n

s p a c e ; a n d ( 2 ) t o a v o i d a d h e s i o n s b e t w e e n d i f f e r e n t

m i d d l e e a r s t r u c t u r e s t h a t c o u l d c o m p r o m i s e t h e r

f u n c t i o n . I f n o t p o s i t i o n e d p r o p e r l y o r t r i m m e d

s m o o t h l y a t t h e e d g e s , i t c a n e x t r u d e . S p e c i f i c u s e s

a r e d e s c r i b e d i n v a r i o u s c h a p t e r s o f t h i s b o o k

Celfonm. G e l f o a m ( d e n a t u r e d a n i m a l s k i n g e l a t r.)

i s u s e d u n i v e r s a l l y i n o t o l o g i c s u r g e r y . T h i s a b s o r b ­

a b l e g e l a t i n i s a v a i l a b l e as a s!> r i le p o w d e r , s p o n ; e ,

o r f i lm ( 0 . 0 7 5 m m t h i c k ) . O n l v t h e last t w o f o r m s ; r e

u s e d . T h e s t e r i l e s p o n g e f o r m , w h i c h i s c a p a b l e > (

a b s o r b i n g a n d h o l d i n g w i t h i n i t s m e s h e s m a n y tirr, ' s

i ts w e i g h t i n w h o l e b l o o d , i s a b s o r b e d c o m p l e t e l y n

four to s ix w e e k s . I t i s u s e d as a h e m o s t a t i c a g e r t ,

t o p a c k t h e m i d d l e e a r c a v i t y , t o a p p l y p r e s s u - e

b e t w e e n t h e g r a f t a n d t h e t y m p a n i c m e m b r a n e , o

p r o m o t e a m i l d i n f l a m m a t o r y r e a c t i o n n e e d e d :>.

c e r t a i n p o i n t s , a n d a s a v e h i c l e for a n t i b i o t i c - s t e r o 1 i

s o l u t i o n s . G e l f i l m i s a n a p p a r e n t l y b r i t t l e f i lm t h t

b e c o m e s sof t a n d r u b b e r y w h e n m o i s t e n e d i n s a l i n .

I t i s u s e d t o d i s c o u r a g e a d h e s i o n s , s u c h a s i n s e p : •

r a t i o n o f t h e i n c u d o s t a p e d i a l j o i n t f r o m t h e t y m p a n . c

m e m b r a n e . I n i ts d r y f o r m , G e l f o a m s h o u l d b e d t •

c o m p r e s s e d ; w h e n s a t u r a t e d , i t s h o u l d b e s q u e e z e i

i n o r d e r t o r e m o v e a i r b u b b l e s . G e l f i l m i s n o t u se f t , !

a s a g ra f t for t y m p a n i c m e m b r a n e p e r f o r a t i o n s .

G e l f o a m s w e l l s a s i t a b s o r b s f l u i d . A s i t e x p a n d ?

i t i m p i n g e s o n n e i g h b o r i n g s t r u c t u r e s ( w h i c h i s w h i

T y m p a n o p l a s t y 223

i t w o r k s w e l l i n f i l l i n g t h e m i d d l e e a r c a v i t y w h e n

a n u n d e r l a y gra f t i s p l a c e d ) . G e l f o a m p o t e n t i a l l y m a y

b e c o m e a f o c u s o f i n f e c t i o n .

T i ssue Adhes ions ( " G l u e s " ) . G l u e s h a v e b e e n t h e

d r e a m o f m a n y o t o l o g i s t s for y e a r s . H i s t o a c r y l ( c y -

a n o b u t y l a c r y l a t e ) a n d F i b r i n , t h e t w o t y p e s t h a t a r e

a v a i l a b l e , w o r k fa i r ly a c c e p t a b l y b u t a r e far f r o m

i d e a l . E i t h e r t h e y m u s t a w a i t t h e t e s t o f t i m e o r w e

m u s t a w a i t a b e t t e r a d h e s i v e . T h e d e s c r i p t i o n o f

t h e m i s b e y o n d t h e s c o p e o f t h i s b o o k .

l o o k e d for ( F i g . 1 2 - 2 D , E ) . T h e t y m p a n i c m e m b r a n e

i t s e l f m a y b e n o r m a l , a t r o p h i c , s c l e r o t i c , t h i c k , re­

t r a c t e d , o r a d h e s i v e .

T h e s e c o n o i t i o n s g i v e a n i n d e x o f s u c h f a c t o r s a s

t h e u n d e r l y i n g c a u s e , e u s t a c h i a n t u b e f u n c t i o n , a e r ­

a t i o n , v a s c u l a r i t y o f t h e m e m b r a n e , a n d s o o n . All

o f t h e s e w i l l a f f e c t t h e g r a f t t a k e a n d i n f l u e n c e t h e

s e l e c t i o n o f t h e t y p e o f r e p a i r .

Approach

Myringoplasty-Type I Tympanoplasty T h e r e a r e n o f i x e d r u l e s f o r a c h i e v i n g t h e f ina l

p u r p o s e , w h i c h i s a d e q u a t e v i s u a l i z a t i o n t h r o u g h a n

o p e n c a n a l , a l l o w i n g a g o o d a s s e s s m e n t a n d r e p a i r .

A m y r i n g o p l a s t y a n d a t y p e I t y m p a n o p l a s t y in - T h e a p p r o a c h s h o u l d p r o v i d e a c l e a r v i s u a l i z a t i o n

v o l v e r e p a i r o f t h e t y m p a n i c m e m b r a n e a l o n e . " M y - a r o u n d t h e b o r d e r s o f t h e p e r f o r a t i o n a n d , i d e a l l y ,

r i n g o p l a s t y " i s t h e t e r m u s e d w h e n t h e o p e r a t i o n c l e a r v i s u a l i z a t i o n o f t h e e n t i r e a n n u l u s . O t o l o g i s t s

d o e s n o t i n c l u d e r a i s i n g f l aps t o e n t e r t h e m i d d l e e a r s h o u l d b e c a p a b l e o f a d a p t i n g t h e a p p r o a c h t o t h e

c a v i t y , . w h e r e a s a t v p e I t y m p a n o p l a s t y i m p l i e s t h e n e e d s o f t h e c a s e a n d n o t v i c e v e r s a . T h e r e a r e a

o p p o s i t e . D i f f e r e n t ' t y p e s ' o f t y m p a n o p l a s t i e s a n d n u m b e r o f s i t u a t i o n s i n w h i c h o n e a p p r o a c h h a s

o s s i c u l o p l a s t i e s i n v o l v e p r o c e d u r e s i n t h e d i f f e r e n t c e r t a i n a d v a n t a g e s o v e r o t h e r s . T h e y wi l l b e h i g h -

s t r u c t u r e s o f t h e m i d d l e e a r a t o r b e y o n d ( m e d i a l t o ) l i g h t e d w i t h t h e u n d e r s t a n d i n g t h a t all g u i d e l i n e s

t h e t y m p a n i c m e m b r a n e . T h e b r o a d t e r m " t y m p a - a r e r e l a t i v e .

n o p l a s t y " i s u s e d fo r a n y p r o c e d u r e w h o s e p u r p o s e T h e a l t e r n a t i v e a p p r o a c h e s a r e t h e t r a n s c a n a l , t h e

i s t o e r a d i c a t e d i s e a s e a n d r e c o n s t r u c t t h e h e a r i n g e n d a u r a l , a n d t h e p o s t a u r i c u l a r . A t r a n s c a n a l a p -

m e c h a n i s m w i t h o r w i t h o u t t y m p a n i c m e m b r a n e p r o a c h i s u s e d i n g e n e r a l f o r s m a l l p e r f o r a t i o n s , o r

g r a f t i n g . P r o v i d e d t h a t all t h e i n t e r d e p e n d e n t f a c t o r s for m e d i u m p o s t e r i o r p e r f o r a t i o n s i n a w i d e c a n a l

p r e v i o u s l y d e s c r i b e d a r e u n d e r c o n t r o l , a n o v e r a l l t h a t a l l o w s a c l e a r v i s u a l i z a t i o n o f t h e a n t e r i o r b o r d e r

a n a l y s i s o f t h e r e q u i r e d p r o c e d u r e i n v o l v e s s e v e r a l o f t h e p e r f o r a t i o n . I t i s i n a d e q u a t e for p e r f o r a t i o n s

a s p e c t s . ' h a t a r e l a r g e o r t h a t i n v o l v e t h e a n n u l u s , o r for

T h e a n a t o m y o f t h e t y m p a n i c m e m b r a n e m u s t b e c a s e s t h a t m i g h t n e e d a n a s s o c i a t e d m a s t o i d p r o c e -

c o n s i d e r e d . T h i s i n c l u d e s n o t o n l y t h e s i t e a n d e x t e n t d u r e . A n e n d a u r a l a p p r o a c h p r o v i d e s g o o d v i s i b i l i t y ,

o f t h e p e r f o r a t i o n b u t a l s o t h e s t a t u s o f t h e m e m b r a n e e s p e c i a l l y o f t h e p o s t e r i o r q u a d r a n t s . F o r a n t e r i o r

( a t r o p h i c , a t e l e c t a t i c , w i t h t y m p a n o s c l e r o t i c p l a q u e s , p e r f o r a t i o n s , a n a s s o c i a t e d c a n a l p l a s t y i s n e c e s s a r y ,

a n d s o o n ) . B a s e d o n t h i s i n f o r m a t i o n , a n a p p r o a c h T h i s a p p r o a c h a l l o w s a m e a t o p l a s t y i n c a s e s o f a

i s s e l e c t e d , t y p e s o f s k i n f l aps ( i f a n y ) a n d g r a f t i n g s m a l l , t h i c k m e a t u s . A p o s t a u r i c u l a r a p p r o a c h a l s o

m a t e r i a l t o b e u s e d a r e c h o s e n , a n d p o s i t i o n i n g o f p r o v i d e s g o o d v i s i b i l i t y , e s p e c i a l l y o f t h e a n t e r i o r

t h e g r a f t i s d e c i d e d ( u n d e r l a y u n d e r t h e m e m b r a n e m a r g i n o f t h e t y m p a n i c m e m b r a n e : i t a l l o w s t h i s

o r o v e r l a y o v e r t h e m e m b r a n e ) . v i e w w i t h o u t a c a n a l p l a s t y . I t i s u s e f u l f o r m e d i u m

A t y m p a n i c m e m b r a n e p e r f o r a t i o n m a y b e r e - t o l a r g e p e r f o r a t i o n s a s w e l l a s a n t e r o i n f e r i o r p e r f o -

s t r i c t e d t o o n e q u a d r a n t a l o n e — t h e p o s t e r o s u p e r i o r , r a t i o n s , w i t h o r w i t h o u t a l t e r a t i o n o f t h e a n n u l u s .

p o s t e r o i n f e r i o r , a n t e r o s u p e r i o r , o r a n t e r o i n f e r i o r . A R e g a r d l e s s o f t h e a p p r o a c h , p r e s e r v a t i o n o f t h e a n -

p e r f o r a t i o n o f S h r a p n e l l ' s m e m b r a n e c o n s t i t u t e s a n n u l u s m a i n t a i n s t h e m i d d l e e a r s p a c e , p r o v i d e s s u p -

e x c e p t i o n t o t h i s ; e x p l o r a t i o n i s a d v i s e d i n all c a s e s . p o r t , a n d r e d u c e s t h e r i s k o f r e t r a c t i o n .

B e c a u s e o f t h e a n a t o m i c p o s i t i o n o f S h r a p n e l l ' s m e m - R e v i s i o n s u r g e r y i n g e n e r a l i s d o n e via a n a l t e r n a t e

b r a n e , e p i t h e l i a l i n g r o w t h i s a l w a y s a p o s s i b i l i t y , i n c i s i o n t h a t a l l o w s a g ra f t t o b e o b t a i n e d . T h e m a i n

e v e n w i t h a n o r m a l a u d i o g r a m ( fo r e x a m p l e , a " c o n - q u e s t i o n s i n r e v i s i o n s a r e ( 1 ) W h y d i d t h e p r o c e d u r e

d u c t i v e " c h o l e s t e a t o m a ) . A p e r f o r a t i o n a l s o c a n in - fail i n i t i a l l y ? ( 2 ) W a s f a i l u r e c a u s e d b y e x p o s u r e ,

v o l v e m o r e t h a n o n e q u a d r a n t ( F i g . 1 2 - 2 A , B ) , o r i t c l i n i c a l e r r o r , o r u n d e r l y i n g d i s e a s e ?

m a y i n v o l v e t h e a n n u l u s . I t c a n b e t o t a l ( F i g . 1 2 - 2 C ) , W h i c h e v e r a p p r o a c h i s c h o s e n , t h e c a n a l s h o u l d

c e n t r a l , o r m a r g i n a l . I f t h e r e a r e s e v e r a l p e r f o r a t i o n s , b e s m o o t h a n d t h e r e s h o u l d b e n o b o n y o v e r h a n g s ,

u n d e r l y i n g d i s e a s e ( s u c h a s t u b e r c u l o s i s ) s h o u l d b e I f t h e a n n u l u s i s m i s s i n g , a s u l c u s (if n e c e s s a r y )

224 T y m p a n o p l a s t y

E

FIGURI; 12-2

T y m p a n o p l a s t y 225

s h o u l d b e c r e a t e d ( t o p r e v e n t b l u n t i n g ) . I f a n a t t i c o ­

t o m y i s p e r f o r m e d , t h e a t t i c m u s t b e r e i n f o r c e d . I f

t h e e u s t a c h i a n t u b e i s d y s f u n c t i o n a l a P E t u b e s h o u l d

b e c o n s i d e r e d .

O n c e t h e a p p r o a c h h a s b e e n s e l e c t e d a n d p e r ­

f o r m e d a n d t h e t y m p a n i c m e m b r a n e i s v i s u a l i z e d ,

t h e n e x t d e c i s i o n i s t h e c a n a l i n c i s i o n s t o u s e . ( B e f o r e

e l e v a t i n g t h e f l a p s , a n y t y m p a n i c m e m b r a n e w o r k

[ s u c h a s t r i m m i n g t h e e d g e s ] s h o u l d b e p e r f o r m e d ,

s i n c e i t i s s i m p l e r a t t h i s t i m e a n d t h e m e m b r a n e i s

i n i ts n a t u r a l p o s i t i o n . ) T h e b a s i c p r i n c i p l e i s t o e n t e r

t h e m i d d l e e a r c a v i t y ( t y p e 1 t y m p a n o p l a s t y ) i n a

w a y t h a t a l l o w s a d e q u a t e i n s p e c t i o n o f t h e c a v i t y

a n d e f f i c i e n t p l a c e m e n t o f a g r a f t . T h e a l t e r n a t i v e s

a r e m a n y a n d v a r y a c c o r d i n g t o n e e d a n d p r e f e r e n c e ,

a s w e l l a s t h e i m a g i n a t i o n o f t h e s u r g e o n , A c l a s s i c

p o s t e r i o r c a n a l f l ap ( 1 a n d 6 o ' c l o c k v e r t i c a l i n c i s i o n s )

o f f e r s a d e q u a t e e x p o s u r e i n m o s t ( i f n o t a l l ) c a s e s

a n d i s a g o o d a l t e r n a t i v e . A n a n t e r i o r o r a n i n f e r i o r

f lap m i g h t s u f f i c e ( F i g . 1 2 - 3 A - C ) , o r a " s w i n g i n g

d o o r " t e c h n i q u e c a n b e u s e d ( F i g . 1 2 - 3 D , E ) . I f s k i n

r e i n f o r c e m e n t i s n e e d e d , a p e d i c l e d f l ap c a n b e

u t i l i z e d . S o m e o f t h e m o s t c o m m o n l y u s e d f l a p s wi l l

b e d e s c r i b e d i n t h e d i s c u s s i o n o f s p e c i f i c p r o c e d u r e s .

T h e y a r e s i m p l y a l t e r n a t i v e s a n d a r e n o t n e c e s s a r i l y

t h e o n l y c h o i c e s .

Small Central Perforation

T h e e d g e s o f t h e p e r f o r a t i o n a r e t o u c h e d w i t h a

b l u n t p i c k m o i s t e n e d i n t r i c h l o r o a c e t i c a c i d ( F i g . 1 2 -

4 / 1 ) . U p o n c o n t a c t w i t h t h e a c i d , t h e e d g e s a c q u i r e a

w h i t e a p p e a r a n c e . A p a p e r p a t c h ( c i g a r e t t e p a p e r ) i s

a p p l i e d o v e r l y i n g t h e p e r f o r a t i o n ( F i g . 1 2 - 4 6 ) . I t i s

i m p o r t a n t t o p r e v e n t a n y a c i d f r o m fa l l i ng i n t o t h e

m i d d l e e a r c a v i t y s i n c e t h i s i s e x t r e m e l y p a i n f u l ; t h e

i n s t r u m e n t s h o u l d b e b a r e l y m o i s t e n e d . I f t h i s c o m ­

p l i c a t i o n o c c u r s , n e u t r a l p H o t i c d r o p s s h o u l d b e

u s e d i n c o n j u n c t i o n w i t h a n a n t i - i n f l a m m a t o r y m e d ­

i c a t i o n . T h i s d o e s n o t w o r k a l l t h e t i m e a n d c a n o n l y

be u s e d for a s m a l l p e r f o r a t i o n i n a h e a l t h y m e m ­

b r a n e .

F o r t i n y c e n t r a l p e r f o r a t i o n s , t h e e d g e s c a n b e

t r i m m e d ( F i g . 1 2 - 4 C , D ) ; a s m a l l t r i a n g l e w e d g e w i t h

its b a s e i n t h e a n n u l u s i s t h e n c r e a t e d ( F i g . 1 2 - 4 E ) .

T h e a n n u l u s i s e l e v a t e d ( a n t e r o p o s t e r i o r e d g e ) a n d

s l id t o w a r d t h e p r o x i m a l ( n o n e l e v a t e d ) e d g e , a l l o w ­

i n g t h e e d g e s o f t h e t y m p a n i c m e m b r a n e t o c o m e

t o g e t h e r ( F i g . 1 2 - 4 F ) . S m a l l p i e c e s o f G e l f o a m a r e

a p p l i e d o v e r t h e a p p r o x i m a t e d e d g e s

F o r a v e r y s m a l l c e n t r a l p e r f o r a t i o n t h a t r e q u i r e s

g r a f t i n g , t h e e d g e s a r e t r i m m e d a n d t h e u n d e r s u r f a c e

o f t h e m e m b r a n e i s g e n t l y s c r a p e d . I n s t e a d o f r a i s i n g

a f l ap , a n i n c i s i o n i s m a d e i n t h e m i d d l e o f t h e

p e r f o r a t i o n a n d t o w a r d t h e a n n u l u s ( F i g . 1 2 - 5 / 1 , B )

T h e t y m p a n i c m e m b r a n e i s c a r e f u l l y r e f l e c t e d , a l l o w ­

i n g e n o u g h s p a c e t o a p p l y G e l f o a m i n t h e m i d d l e

e a r a n d a m e d i a l ( u n d e r l a y ) g ra f t ( F i g . 1 2 - 5 C ) . T h e

t y m p a n i c m e m b r a n e i s r e p o s i t i o n e d a n d G e l f o a m i s

a p p l i e d o v e r i t ( F i g . 1 2 - 5 D ) .

F o r a s m a l l c e n t r a l p e r f o r a t i o n , a n u n d e r l a y g ra f t

i s p l a c e d t h r o u g h t h e p e r f o r a t i o n ( F i g . 1 2 - 5 E ) , T h e

e d g e s o f t h e p e r f o r a t i o n a r e t r i m m e d m e t i c u l o u s l y ,

a n d t h e u n d e r s u r f a c e o f t h e m e m b r a n e i s g e n t l y

s c r a p e d ( f r e s h e n e d ) ; t h i s i n c l u d e s c l e a n s i n g (if

n e e d e d ) o f t h e m a n u b r i u m . T h e m i d d l e e a r c a v i t y i s

f i l l e d w i t h c o m p r e s s e d G e l f o a m ( F i g . 1 2 - 5 F ) a n d a

f a s c i a g r a f t i s p l a c e d t h r o u g h t h e p e r f o r a t i o n , m a k i n g

s u r e t h a t t h e e d g e s o f t h e p e r f o r a t i o n a r e o v e r l a p p e d

b y t h e g r a f t b y m o r e t h a n 3 0 % . I f n e e d e d , a p i e c e o f

f a s c i a i s p l a c e d b e t w e e n t h e t y m p a n i c m e m b r a n e a n d

t h e l o n g p r o c e s s o f t h e m a l l e u s . T h e m a l l e u s h a n d l e

c a n b e d e - e p i t h e l i a l i z e d a n d a p i e c e o f f a s c i a p l a c e d

l a t e r a l l y .

T h e s e p r o c e d u r e s r e q u i r e a h e a l t h y , w e l l - v a s c u l a r -

i z ed t y m p a n i c m e m b r a n e .

Overlay Technique in Central Perforation

Critical Points

1 . C o m p ' e t e d e - e p i t h e l i a l i z a t i o n .

2 . A w e l l - d e f i n e d , w e l l - p l a c e d a n t e r i o r t y m p a n o -

m e a t a l a n g l e j u n c t i o n .

3 . A t t a c h m e n t o f g ra f t t o h a n d l e o f m a l l e u s .

Procedure

A p o s t a u r i c u l a r a p p r o a c h h a s b e e n s e l e c t e d a n d a

t e m p o r a l f a s c i a l g r a f t o b t a i n e d . T h e i n c i s i o n o f t h e

p o s t e r i o r c a n a l i s m a d e a t t h e j u n c t i o n o f t h e l a t e r a l

a n d m i d d l e t h i r d s o f t h e c a n a l . T h i s p r o c e d u r e in­

v o l v e s r e m o v a l o f t h e c a n a l s k i n f r o m t h i s j u n c t i o n

d o w n t o 2 m m l a t e r a l t o t h e a n n u l u s ( e x c e p t i n g t h e

a r e a o f s k i n c o n t a i n i n g t h e v a s c u l a r s t r i p ) . V e r t i c a l

i n c i s i o n s a r e m a d e a t 1 0 a n d 1 o ' c l o c k ( F i g . 1 2 - 6 / 1 ) .

T w o c i r c u m f e r e n t i a l i n c i s i o n s a r e m a d e , t h e f irst 2

m m l a t e r a l t o t h e a n n u l u s ( e x c e p t i n g t h e a r e a b e ­

t w e e n 1 0 a n d 1 o ' c l o c k ) a n d t h e s e c o n d a t t h e j u n c t i o n

o f t h e l a t e r a l a n d m i d d l e t h i r d s o f t h e c a n a l . ( T h i s i s

a n e x t e n s i o n o f t h e c a n a l i n c i s i o n a l o n g t h e w h o l e

c i r c u m f e r e n c e . ) T h e s k i n i s c a r e f u l l y e l e v a t e d i n o n e

p i e c e a n d p r e s e r v e d . A c a n a l p l a s t y i s d o n e i f n e e d e d .

T h e t y m p a n i c m e m b r a n e i s m e t i c u l o u s l y d e - e p i t h e -

Text continued on page 2 3 0

Tympanoplasty 227

E

fiCURE 12-4

.....----------------.,....""(~

\1

rieUR!' 12-3

226 Tympanoplasty

228 T y m p a n o p l a s t y T y m p a n o p l a s t y 229

230 T y m p a n o p l a s t y

l i a l i z e d w i t h a j o i n t o r N o . 2 c a n a l k n i f e o r s m a l l

c u r e t s ( F i g . 1 2 - 6 8 ) . T h e m i d d l e e a r i s f i l l ed w i t h

c o m p r e s s e d G e l f o a m , a n d t h e g ra f t i s n o t c h e d t o fit

a r o u n d t h e m a n u b r i u m ( F i g . 1 2 - 6 C ) . ( T h e m a n u ­

b r i u m i s d e - e p i t h e l i a l i z e d a n d c l e a n s e d . ) T h e g ra f t i s

p l a c e d e m b r a c i n g t h e m a n u b r i u m ; i f n e e d e d , a p i e c e

o f f a s c i a i s p l a c e d o v e r t h e m a l l e u s h a n d l e ( F i g . 1 2 -

6 D ) . T h e s k i n g r a f t i s t h e n r e t u r n e d , o v e r l a p p i n g t h e

f a sc i a f o r a f e w m i l l i m e t e r s . S p e c i a l c a r e m u s t b e

o b s e r v e d a n t e r i o r l y i n o r d e r t o a v o i d b l u n t m g o f t h e

g r a f t i n t h e a n t e r i o r t y m p a n o m e a t a l a n g l e . T h e c a n a l

i s p a c k e d , u s u a l l y w i t h G e l f o a m i n t h e m e d i a l t w o

t h i r d s ( F i g . 1 2 - 6 F ) . I n c a s e s w h e r e t h e r e i s n o f i b r o u s

a n n u l u s , t h e s u l c u s s h o u l d b e c h e c k e d ; i f s h a l l o w , i t

c a n b e d r i l l e d w i t h a s m a l l b u r . I n c i s i o n s a r e c l o s e d

w i t h a p p r o p r i a t e s u t u r e s a n d a d r e s s i n g i s a p p l i e d .

Problems and Complicat ions

B l u n t i n g o f t h e a n t e r i o r t y m p a n o m e a t a l a n g l e i s

t h e m o s t f e a r e d c o m p l i c a t i o n , a n d u s u a l l y o c c u r s

w h e n t h e r e i s n o a n n u l u s a n d n o s u l c u s . D r i l l i n g o f

t h e s u l c u s i s h e l p f u l . T i g h t p a c k i n g a t t h i s a n g l e i s

i m p o r t a n t ( r o s e b u d p a c k i n g w i t h O w e n ' s s i lk w o r k s

q u i t e w e l l for t h i s p u r p o s e ) . L a t e r a l i z a t i o n o f t h e

g ra f t ( l a t e r a l d i s p l a c e m e n t ) h a p p e n s l e s s f r e q u e n t l y

i f t h e t i p o f t h e m a l l e u s h a n d l e i s p l a c e d o v e r t h e

f a s c i a . R e s i d u a l c h o l e s t e a t o m a o c c u r s w h e n d c - e p i -

t h e l i a l i z a t i o n o f t h e t y m p a n i c m e m b r a n e i s i n c o m ­

p l e t e . R e p e r f o r a t i o n a n t e r i o r l y i s e s p e c i a l l y c o m m o n

i f t h e r e i s n o a n n u l u s . T h i s i s i n v o l v e d w i t h s u p p o r t

o f t h e g ra f t ( b y t h e a n n u l u s ) a n d v a s c u l a r i z a t i o n i n

t h e a r e a

Underlay Graft for Posterior Perforation in Atrophic Membrane

U s i n g a n e n d a u r a l a p p r o a c h , a t e m p o r a l f a sc i a

g r a f t ( b y L e m p e r t I i n c i s i o n ) a n d a s m a l l s k i n g ra f t

( b y a L e m p e r t I I i n c i s i o n ) h a v e b e e n o b t a i n e d . T h e

t y m p a n i c m e m b r a n e i s v i s u a l i z e d ; i f n e c e s s a r y , a

c a n a l p l a s t y i s d o n e . T h e e d g e s o f t h e p e r f o r a t i o n a r e

t r i m m e d , t h e u n d e r s u r f a c e o f t h e m e m b r a n e i s g e n t l y

s c r a p e d , a n d t h e m e m b r a n e i s d e - e p i t h e l i a l i z e d .

C o m p l e t e d e - e p i t h e l i a l i z a t i o n m u s t b e d o n e i f a s k i n

g r a f t i s t o b e u s e d . I f t h e m e m b r a n e i s a t r o p h i c ,

• h o w e v e r , c o m p l e t e d e - e p i t h e l i a l i z a t i o n m i g h t b e

m o r e h a r m f u l t h a n u s e f u l ( a n u n d e r l a y gra f t i s b e i n g

u s e d ) b e c a u s e o f t h e p o t e n t i a l for t e a r s .

I f a P E t u b e i s b e i n g c o n s i d e r e d , t h i s i s t h e t i m e

t o s e l e c t a n a r e a a n d p l a c e it.

I n t h i s e x a m p l e , a c l a s s i c p o s t e r i o r c a n a l f lap w i t h

v e r t i c a l i n c i s i o n s a t 1 a n d 6 o ' c l o c k i s u s e d ( F i g . 1 >-

7 A); t h i s i s a g o o d c h o i c e b u t n o t t h e o n l y o n e . T u e

f l a p i s r a i s e d , a n d t h e m i d d l e e a r c a v i t y i s e n t e r , d

b e n e a t h t h e a n n u l u s R e m e m b e r t h a t t h e a n n u l , s

p r o v i d e s s u p p o r t a n d a l l o w s for m a i n t e n a n c e o f t i e

m i d d l e e a r s p a c e . T h e m i d d l e e a r s p a c e i s i n s p e c t e i .

( F o r i n s p e c t i o n a n d e v a l u a t i o n , s e e T y m p a n o p l a s y

for A t e l e c t a t i c T y m p a n i c M e m b r a n e i n C h a p t e r I f . )

F o r t h i s p r o c e d u r e ( r e p a i r o f a p e r f o r a t i o n a n d r e i n ­

f o r c e m e n t o f t h e m e m b r a n e ) i t i s a s s u m e d t o t e

n o r m a l .

A p i e c e o f t h i n S i l a s t i c s h e e t i n g i s p l a c e d f r o m tl"2

s i n u s t y m p a n i c a r e a t o t h e e u s t a c h i a n t u b e . T h s

m i d d l e e a r c a v i t y i s f i l led w i t h c o m p r e s s e d G e l f o a n ,

a n d a p i e c e o f G e l f i l m i s p l a c e d o v e r t h e i n c u d o s t i -

p e d i a l j o i n t ( n o t u n d e r t h e a n n u l u s ) , b e t w e e n t h t

j o i n t a n d t h e m e m b r a n e , i n o r d e r t o a v o i d a d h e s i o n s

f r o m t h e gra f t t o t h e j o i n t ( F i g . 1 2 - 7 8 ) .

T h e f a sc i a g r a f t i s p o s i t i o n e d o v e r a n a r e a 3 0 ?

g r e a t e r t h a n t h e e x t e n t o f t h e p e r f o r a t i o n , s i n c e i :

w i l l r e t r a c t b y a b o u t 3 0 % ( F i g . 1 2 - 7 C ) . O n e c o n c e r t :

w i t h g r a f t s i s t h e p o s s i b i l i t y o f l ack o f a d e q u a t i

c o n t a c t w i t h t h e o v e r l y i n g t y m p a n i c m e m b r a n e . B )

t h i s " f a l l i n g i n t o t h e m i d d l e e a r c a v i t y " t h e b r i d g i n g

f u n c t i o n m i g h t b e l o s t . A l t h o u g h c o m p r e s s e d G e l ­

f o a m p r o v i d e s a d e q u a t e c o n t a c t ( i f p l a c e d c o r r e c t l y ) ,

a s o u n d a l t e r n a t i v e ( w i t h p r o v e n g o o d r e s u l t s ) i s t h e

u s e o f m i c r o c l i p s t o s e c u r e t h e g r a f t a g a i n s t t h e

o v e r l y i n g m e m b r a n e . I f t h e t y m p a n i c m e m b r a n e i s

w e l l d e - e p i t h e l i a l i z e d t h e c l i p s wi l l n o t c a u s e a p r o b ­

l e m ; e v e n t u a l l y t h e v wi l l b e e x t r u d e d . ( T h i s t e c h ­

n i q u e i s n o t d e s c r i b e d i n t h i s a t l a s . ) I t i s u s e f u l t o

l e a v e a tail ( o f t h e f a s c i a ) t o w a r d t h e p o s t e r i o r b o n •

c a n a l t o b e r e m o v e d . T h i s s h o u l d b e d o n e v e r v

c o n s e r v a t i v e l y ( i f a t all p o s s i b l e ) i n o r d e r t o a v o i d

h a v i n g t h e g ra f t r e s t o v e r t h e i n c u d o s t a p e d i a l j o i n t

( w h i c h b y n o w i s c o v e r e d w i t h G e l f i l m ) . T h e gra f t i s

p l a c e d e m b r a c i n g t h e h a n d l e o f t h e m a l l e u s . A s m a l l

p i e c e o f f a sc i a c a n t h e n b e p l a c e d o v e r t h e h a n d l e .

T h e p i e c e o f s k i n h a r v e s t e d v ia t h e L e m p e r t I I i n c i ­

s i o n i s p l a c e d o v e r t h e f a s c i a ( c o v e r i n g t h e p e r f o r a ­

t i o n ) ( F i g . 1 2 - 7 D ) . T h e e a r i s p a c k e d ( F i g . 1 2 - 7 E ) .

E n d a u r a l i n c i s i o n s a r e c l o s e d w i t h t h e a p p r o p r i a t e

s u t u r e s , a n d a d r e s s i n g i s a p p l i e d .

Underlay Graft for Large Anterior Perforation

A t e m p o r a l f a s c i a g ra f t h a s b e e n o b t a i n e d v i a th<

p o s t a u r i c u l a r a p p r o a c h . A p o s t e r i o r c a n a l i n c i s i o n v

m a d e a t t h e b o n y c a r t i l a g i n o u s j u n c t i o n . T h e t y m

p a n i c m e m b r a n e i s v i s u a l i z e d , t h e e d g e s o f t h e per­

f o r a t i o n a r e t r i m m e d , t h e u n d e r s u r f a c e i s s c r a p e d ,

T y m p a n o p l a s t y 2 3 1

FIGURE 1 2 - 7 .

rïCURE 12

T y m p a n o p l a s t y 233

a n d t h e m e m b r a n e i s d e - e p i t h e l i a l i z e d . ( I t i s a s s u m e d

t h a t a c a n a l p l a s t y i s n o t n e e d e d . )

I n c i s i o n s a r e m a d e for t h e f lap ( a c l a s s i c p o s t e r i o r

c a n a l t y m p a n o p l a s t y i n c i s i o n , a l t h o u g h o t h e r s c o u l d

h a v e b e e n m a d e a s w e l l ) ( F i g . 1 2 - 8 4 ) . T h e " s w i n g i n g

d o o r s " i m p l y t h e e l e v a t i o n o f s u p e r i o r l y a n d i n f e r i -

o r l y b a s e d s k i n f l a p s . T h e h o r i z o n t a l i n c i s i o n i s m a d e

5 t o 7 m m l a t e r a l t o t h e a n n u l u s . T h e f l ap i s d i v i d e d

w i t h a v e r t i c a l i n c i s i o n a t 9 o ' c l o c k (it c o u l d a l s o be

a t 1 1 o ' c l o c k ) ; t h i s i n c i s i o n i n v o l v e s b o t h t h e t y m p a n i c

m e m b r a n e a n d t h e a n n u l u s . T h i s r e s u l t s i n t w o f l a p s

( o n e s u p e r i o r l y a n d o n e i n f e r i o r l y b a s e d ) , w h i c h a r e

e l e v a t e d a n t e r i o r l y u p t o ( a n d b e y o n d i f n e c e s s a r y )

t h e m a l l e u s s u p e r i o r l y , a n d t o 6 o ' c l o c k ( o r f u r t h e r )

i n f e r i o r l y .

T h e m i d d l e e a r c a v i t y i s e n t e r e d a n d e x a m i n e d

(It i s a s s u m e d t h a t all t h a t i s n e e d e d i s p l a c e m e n t o f

a g r a f t . )

I f o n l y t h e a n n u l u s i s left a n t e r i o r l y , t h e p r o b l e m

o f . g r a f t s u p p o r t b e c o m e s a n i s s u e . A b u n d a n t G e l -

f o a m p a c k i n g s h o u l d b e p l a n n e d . A g o o d c h o i c e i s

t o d e - e p i t h e l i a l i z e t h e a n n u l u s a n t e r i o r l y a n d t o m a k e

s m a l l i n c i s i o n s 3 to 4 mm in l e n g t h ( o r l o n g e r i f

n e e d e d ) a n d r a i s e a s m a l l a n t e r i o r f l a p . T h e a n n u l u s

i s g e n t l y e l e v a t e d a n t e r i o r l y for t h e s a m e e x t e n t a s

t h e i n c i s i o n ( m a d e i n t h e s k i n o f t h e c a n a l ) , a n d t h e

f a sc i a g r a f t i s p u l l e d b e n e a t h t h e a n n u l u s o n t o t h e

a n t e r i o r c a n a l a n d c o v e r e d w i t h t h e s m a l l a n t e r i o r

f l ap ( F i g . 1 2 - 8 B , C ) . T h i s a v o i d s r e t r a c t i o n o f t h e

g ra f t i n s u c h a c r i t i c a l a r e a . ( T h e r e s t o f t h e g ra f t

p o s i t i o n i n g i s s i m i l a r t o t h a t i n t h e e n d a u r a l a p p r o a c h

d e s c r i b e d a b o v e . ) A p i e c e o f t h in S i l a s t i c s h e e t i n g i s

p l a c e d f r o m t h e s i n u s t y m p a n i t o t h e e u s t a c h i a n

t u b e . T h e c a v i t y i s f i l led w i t h c o m p r e s s e d G e l f o a m ;

a p i e c e o f G e l f i l m i s p l a c e d o v e r t h e i n c u d o s t a p e d i a l

j o i n t . T h e g ra f t i s p l a c e d p o s t e r i o r l y a s w e l l , a n d t h e

f l aps a r e r e p o s i t i o n e d ( F i g . 1 2 - 8 D ) . ( N o t e t h e d i s t i n c t

a d v a n t a g e o f l e a v i n g t h e v a s c u l a r s t r i p u n t o u c h e d . )

P a c k i n g i s d o n e . I n c i s i o n s a r e c l o s e d w i t h a p p r o p r i a t e

s u t u r e s , a n d a d r e s s i n g i s a p p l i e d .

Allograft for Total Perforation

T h e u s e o f a n a l l o g e n e i c t y m p a n i c m e m b r a n e

a l l o g r a f t c o n s t i t u t e s o n e m o r e e f f e c t i v e m e a n s o f

r e s t o r i n g c o n t i n u i t y o f t h e m e m b r a n e . I t s i n d i c a t i o n s

a r e s i m i l a r t o o t h e r s , b u t t h i s g ra f t i s e s p e c i a l l y u s e d

for f a i l u r e s o f s t a n d a r d t y m p a n o p l a s t y ( s u c h a s re­

c u r r e n t p e r f o r a t i o n s o r l a t e r a l i z a t i o n o f g r a f t s ) , a n d

i n c a s e s i n w h i c h t h e r e i s a h i g h r i sk o f f a i l u r e w i t h

s t a n d a r d t y m p a n o p l a s t y . A n a l l o g r a f t i s n o t a p a n a ­

c e a a n d i s n o t e a s y t o p o s i t i o n a d e q u a t e l y ; h o w e v e r ,

i t a l l o w s t h e u s e o f t h e t y m p a n i c m e m b r a n e o r

o s s i c l e s , o r a t y m p a n i c m e m b r a n e w i t h o s s i c l e s . A

d o n o r m e m b r a n e m u s t b e s e l e c t e d o f t h e p r o p e r s i z e

a n d s i d e t o fit w e l l i n t h e r e c i p i e n t .

A s s u m i n g e i t h e r a n e n d a u r a l o r a p o s t a u r i c u l a r

a p p r o a c h , e n o u g h b o n e i s r e m o v e d ( b y c a n a l p l a s t y )

t o c o m p l e t e l y v i s u a l i z e t h e a n n u l u s ( o r t h e s u l c u s , i f

t h e a n n u l u s i s n o t p r e s e n t ) . T h e m a l l e u s h a n d l e i s

m e t i c u l o u s l y c l e a n s e d , a n d t h e t y m p a n i c m e m b r a n e

r e m n a n t s a r e d e - e p i t h e l i a l i z e d . I f t h e a n n u l u s i s

a b s e n t , t h e s u l c u s i s c a r e f u l l y d r i l l e d i n o r d e r t o s e a l

t h e a l l o g r a f t i n g o o d p o s i t i o n .

I n c i s i o n s a r e m a d e a t 1 1 , 2 , a n d 7 o ' c l o c k a n d

i n c l u d e t h e a n n u l u s , u n l e s s t h e a n n u l u s i s c o m p l e t e

( F i g . 1 2 - 9 4 ) . T h e f l aps e x p o s e t h e m i d d l e e a r c a v i t y .

S o m e G e l f o a m i s p l a c e d , a n d a l l o g r a f t i s p o s i t i o n e d

first o v e r t h e m a l l e u s ( F i g . 1 2 - 9 B ) . T h e f l a p s a r e t h e n

r e p o s i t i o n e d . P a c k i n g i s d o n e , t h e i n c i s i o n s a r e

c l o s e d ( F i g . 1 2 - 9 C ) , a n d a d r e s s i n g i s a p p l i e d

A n a l l o g e n e i c t y m p a n i c m e m b r a n e g ra f t h a s c e r ­

ta in d r a w b a c k s . D i f f e r e n t s i d e s ( r i g h t o r lef t ) a n d

s i z e s m u s t b e a v a i l a b l e i n t h e o p e r a t i n g r o o m . I t i s

n o t e a s y t o p o s i t i o n t h e g ra f t p r o p e r l y . A l l o g r a f t s

t e n d t o f o r m a d h e s i o n s a n d a r e a s s o c i a t e d w i t h

g r a n u l a t i o n t i s s u e i n t h e m i d d l e e a r c a v i t y . ( S i l a s t i c

s h o u l d b e u s e d , a s w e l l a s G e l f o a m [ c o n s e r v a t i v e l y ] ) .

I m m u n o l o g i c r e j e c t i o n s o m e t i m e s o c c u r s . ( T h i s i s

fa i r ly w e l l c o n t r o l l e d , h o w e v e r . ) I n a d d i t i o n , t h e r e i s

a p o t e n t i a l for t r a n s m i t t i n g v i ra l p a r t i c l e s f r o m t h e

d o n o r t o t h e r e c i p i e n t , s i n c e s o m e v i r u s e s a r e n o t

e a s i l y e l i m i n a t e d b y s t e r i l i z a t i o n p r o c e s s e s . T h e

s o u r c e o f t h e a l l o g r a f t o b v i o u s l y i s c r i t i c a l

Tympanoplasty-Ossiculoplasty

T h e t i t l e o f t h i s s e c t i o n i s c h o s e n for d i d a c t i c

p u r p o s e s . H o w e v e r , t h e r e a d e r s h o u l d b e a w a r e t h a t

a n o s s i c u l o p l a s t y i s p a r t o f a t y m p a n o p l a s t y . T h e s e

p r o c e d u r e s i n v o l v e r e s t o r i n g t h e s o u n d c o n d u c t i o n

c a p a b i l i t i e s o f t h e o s s i c u l a r c h a i n w i t h o r w i t h o u t a

t y m p a n i c m e m b r a n e g ra f t . T h e e n d r e s u l t s h o u l d b e

c o n t i n u i t y i n v i b r a t i o n o f t h e n e w c h a i n , w i t h a s o l i d

c o n t a c t w i t h l h e t y m p a n i c m e m b r a n e a n d a m o b i l e

o v a l w i n d o w m e m b r a n e o r p l a t e .

T h e o s s i c u l a r c h a i n o r i t s c o m p o n e n t s c a n b e

a f f e c t e d b y f i x a t i o n , d i s l o c a t i o n , f r a c t u r e , o r d i s s o l u ­

t i on ( r e s o r p t i j n ) . T h e s e c o n d i t i o n s m a y b e c o n g e n i ­

tal , o r t h e y c a n b e c a u s e d b y t r a u m a , n e o p l a s m , o r

i n f e c t i o n . Th-.> c h o i c e o f p r o c e d u r e wi l l d e p e n d u p o n

t h e t y p e o f o s s i c u l a r p r o b l e m , t h e a n a t o m i c e n v i r o n ­

m e n t , t h e s p a c e a v a i l a b l e ( i n t a c t p o s t w a l l , c a n a l w a l l

d o w n , a n d s o o n ) , a n d t h e s t a t u s o f t h e m u c o s a

( w h i c h i n t u r n d e p e n d s u p o n t h e s t a t u s o f t h e

234 T y m p a n o p l a s t y

FIGURE 12-9.

• T y m p a n o p l a s t y 235

u n d e r l y i n g d i s e a s e ) . F o r p r a c t i c a l p u r p o s e s , i t i s

a s s u m e d t h a t t h e u n d e r l y i n g d i s e a s e i s u n d e r c o n t r o l

a n d t h a t t h e m i d d l e e a r s p a c e i s a d e q u a t e . Al l p o s ­

s i b l e o s s i c u l a r c h a n g e s a n d e x a m p l e s o f s u r g i c a l

r e p a i r i n s e l e c t e d s i t u a t i o n s wi l l b e d i s c u s s e d , w i t h

t h e u n d e r s t a n d i n g t h a t t h e r e a r e o t h e r c h o i c e s a v a i l ­

a b l e .

Isolated Ossicular Lesions

Malleus ( F i g . 1 2 - 1 0 4 )

T h i s i s a n e s s e n t i a l b o n e i n o s s i c u l o p l a s t y r e p a i r .

T h e p r e s e n c e o r a b s e n c e o f t h e h a n d l e o f t h e m a l l e u s ,

t o g e t h e r w i t h t h e p r e s e n c e o r a b s e n c e o f a n i n t a c t

a n d m o b i l e s t a p e s , w i l l d e t e r m i n e i n g r e a t p a r t t h e

t y p e o f p r o c e d u r e t o b e p e r f o r m e d .

T h e m a l l e u s i s r a r e l y a f f e c t e d a l o n e ; i f i t i s , t h e

p r o b l e m u s u a l l y i s a n a n t e r i o r f i x a t i o n o f t h e h e a d .

(It m a y a l s o be a t r a u m a t i c d i s l o c a t i o n . ) I f i t i s

a s s o c i a t e d w i t h a m o b i l e s t a p e s , a n a t t i c o t o m y i s

d o n e w i t h e x p o s u r e o f t h e i n c u d o m a l l e a l j o i n t ( F i g

1 2 - 1 0 B , C ) ( s e e C h a p t e r 1 3 ) . T h e f i x a t i o n i s v e r i f i e d ,

a n d t h e j o i n t i s s e p a r a t e d w i t h a j o i n t k n i f e .

P o i n t s t o r e m e m b e r : D i s a r t i c u l a t e t h e i n c u d o s t a -

p e d i a l j o i n t b e f o r e d r i l l i n g i n t h e a t t i c . T h i s w i l l h e l p

t o a v o i d i n n e r e a r d a m a g e . R e i n f o r c i n g t h e p o s t e r o -

s u p e r i o r c a n a l q u a d r a n t ( a t t i c o t o m y s i t e ) b e f o r e c l o ­

s u r e w i l l d i s c o u r a g e r e t r a c t i o n p o c k e t s a n d o t h e r

c o m p l i c a t i o n s .

T h e h e a d o f t h e m a l l e u s i s a m p u t a t e d w i t h a

m a l l e u s n i p p e r ( F i g . 1 2 - 1 0 D ) . T h e i n c u s a l s o i s re ­

m o v e d , s i n c e i t h a s l o s t i t s a r t i c u l a t i o n t o t h e h e a d

o f t h e m a l l e u s . R e c o n s t r u c t i o n wi l l b e b a s e d t o w a r d

t h e h e a d o f t h e s t a p e s . T h e r e a r e t w o a l t e r n a t i v e s :

l a y i n g t h e t y m p a n i c m e m b r a n e ( i n t a c t o r g r a f t e d )

o v e r t h e h e a d o f t h e s t a p e s ( c l a s s i c t y p e III t y m p a ­

n o p l a s t y ) ( F i g . 1 2 - 1 0 E ) , a n d p l a c i n g a g r a f t o r p r o s ­

t h e s i s b e t w e e n t h e m o b i l e h a n d l e o f t h e m a l l e u s ( t h e

f i x e d h e a d h a s b e e n a m p u t a t e d ) a n d t h e h e a d o f t h e

s t a p e s . T h e l a t t e r c o u r s e i s b e t t e r i n t e r m s o f re ­

e s t a b l i s h i n g c o n t i n u i t y i n a n a d e q u a t e m i d d l e e a r

s p a c e . T h i s c a n b e d o n e i n a n u m b e r o f w a y s :

1 . U s i n g t h e h e a d o f t h e m a l l e u s . H o l d i n g t h e

h e a d o f t h e m a l l e u s w i t h a n o s s i c l e h o l d e r , s h a p e i t

t o fit b e t w e e n t h e h e a d o f t h e s t a p e s a n d h a n d l e o f

t h e m a l l e u s . Dr i l l a h o l e i n i t t o r e c e i v e t h e h e a d o f

t h e s t a p e s . T h e n f l a t t e n i t ( n o t c h i t a l i t t l e , m a k i n g a

g r o o v e ) t o fit u n d e r t h e h a n d l e ( F i g . 1 2 - 1 0 F ) .

2 . U s i n g t h e i n c u s . T h e s h o r t p r o c e s s o f t h e i n c u s

i s c l i p p e d . A n a c e t a b u l u m i s d r i l l e d i n t h e l o n g

p r o c e s s for f i t t i ng o v e r t h e h e a d o f t h e s t a p e s . T h i s

i s f o l l o w e d b y d r i l l i n g a g r o o v e o v e r t h e r e m a i n i n g

b o d y f o r f i t t i n g u n d e r t h e m a l l e u s h a n d l e ( F i g . 1 2 -

1 1 4 , B ) .

3 . U s i n g c o r t i c a l b o n e . A gra f t t h a t i s s h a p e d

s i m i l a r t o a s c u l p t u r e d i n c u s o r m a l l e u s h e a d c a n b e

d r i l l e d , c r e a t i n g a c o n c a v e h o l e t o fit o v e r t h e h e a d

o f t h e s t a p e s a n d a n o t c h o r a g r o o v e t o f i t u n d e r

t h e m a l l e u s h a n d l e ( F i g . 1 2 - 1 1 C , D ) . ( I f d e s i r e d , a T -

s h a p e d c o r t i c a l b o n e c a n b e u s e d . )

4 . U s i n g a p a r t i a l o s s i c u l a r r e p l a c e m e n t p r o s t h e s i s

( P O R P ) . T h e l a r g e r s u r f a c e a r e a o f a P O R P p r o v i d e s

m o r e s t a b i l i t y ; h o w e v e r , i t m u s t b e c o v e r e d w i t h a

t h i n p i e c e o f c a r t i l a g e ( s u c h a s t r a g a l c a r t i l a g e ) t h a t

e x c e e d s t h e e d g e s o f t h e P O R P . W h e n p l a c e d , i t

m u s t p r o v i d e a s l i g h t t e n s i o n o v e r t h e t y m p a n i c

m e m b r a n e ( F i g . 1 2 - 1 2 4 ) . T h e c a r t i l a g e i s b e t w e e n

t h e P O R P a n d t h e m a l l e u s h a n d l e . I f t h e r e i s n o

m a l l e u s h a n d l e , t h e c a r t i l a g e i s p l a c e d d i r e c t l y u n d e r

t h e t y m p a n i c m e m b r a n e o r t y m p a n i c m e m b r a n e

graf t ; i n t h e s e c a s e s , a l a r g e p i e c e o f c a r t i l a g e i s

p r e f e r r e d . S o m e s u r g e o n s e v e n s u t u r e t h e c a r t i l a g e

t o t h e h e a d o f t h e P O R P . I n t h e d i s t a l p o r t i o n o f t h e

P O R P , a n o p e n i n g o r n o t c h i s m a d e f o r b e t t e r c o n t a c t

w i t h t h e h e a d o f t h e s t a p e s a n d s t a p e d i a l t e n d o n . I n

s o m e c a s e s a P O R P c a n b e c a r v e d f r o m c a r t i l a g e , a n d

t h i s t y p e o f g r a f t f i ts q u i t e w e l l ( F i g . 1 2 - 1 2 B ) . I t a l s o

a l l o w s t r i m m i n g o f t h e h e a d o f t h e c a r t i l a g e P O R P

t o fit t h e a n g l e d p o s i t i o n o f t h e m e m b r a n e ( F i g . 1 2 -

1 2 C ) . I n p o s i t i o n i n g P O R P s ( a n d T O R P s ) , a b u n d a n t

G e l f o a m i s p l a c e d i n t h e m i d d l e e a r c a v i t y i n o r d e r

t o p r o v i d e s u p p o r t a n d m a i n t a i n p o s i t i o n a f t e r r e ­

p o s i t i o n i n g t h e f l a p s a n d t y m p a n i c m e m b r a n e . C e ­

r a m i c P O R P s a r e a l s o a v a i l a b l e ( F i g . 1 2 - 1 2 D ) .

Incus ( F i g . 1 2 - 1 3 4 )

T h e i n c u s p r o b l e m s a n d r e p a i r s d i s c u s s e d h e r e

a s s u m e a n i n t a c t m a l l e u s h a n d l e a n d s t a p e s . T h e

i n c u s i s t h e o s s i c l e m o s t c o m m o n l y a f f e c t e d b y e a r

i n f e c t i o n s ( e r o s i o n o f t h e l e n t i c u l a r p r o c e s s ) a n d

t r a u m a ( f r a c t u r e - d i s l o c a t i o n ) . I t m a y a l s o b e a b s e n t

( o w i n g t o t r a u m a o r p r e v i o u s s u r g e r y ) o r f i xed ( u s u ­

a l ly i n a s s o c i a t i o n w i t h t h e m a l l e u s h e a d ) .

I f e r o s i o n i n v o l v e s a s m a l l p o r t i o n o f t h e d i s t a l

e n d o f t h e l e n t i c u l a r p r o c e s s , c o n t i n u i t y c a n b e re ­

e s t a b l i s h e d b y a n y o f t h e f o l l o w i n g m e t h o d s :

1 . U s i n g a c o r t i c a l b o n e c h i p . A s q u a r e o f b o n e i s

d e l i n e a t e d i n t h e c o r t e x , r e m o v e d , a n d s h a p e d . A

s m a l l a c e t a b u l u m i s d r i l l e d for t h e h e a d o f t h e s t a p e s ,

a n d a g r o o v e for t h e r e m a i n i n g l o n g p r o c e s s o f t h e

i n c u s ( F i g . 1 2 - 1 3 B - E ) .

2 . U s i n g a c a r t i l a g e c h i p . A p i e c e o f c a r t i l a g e

s h a p e d s i m i l a r l y t o t h e c o r t i c a l b o n e c h i p c a n b e

u s e d .

3 . U s i n ^ a p r o s t h e s i s t h a t e m b r a c e s b o t h t h e re ­

m a i n i n g l e i t i c u l a r p r o c e s s a n d t h e h e a d o f t h e s t a p e s .

Text continued on page 2 4 1

237Tympanoplasty

II

lncudoma/lealJOint

B

D

c

A

E Type III

Graft

Tympanoplasty236

FIGURE 12-10.FIGURE 12-11

T y m p a n o p l a s t y

FIGURE 12-13.

T y m p a n o p l a s t y 2 4 1

[ f t h e r e i s d i s l o c a t i o n , t h e i d e a l p r o c e d u r e i s r e a p -

p r o x i m a t i o n a n d r e p o s i t i o n i n g u s i n g G e l f o a m o r

" g l u e " ( F i b r i n o r H i s t o a c r y l ) , o r b o t h . H o w e v e r , t h i s

i s s e l d o m p o s s i b l e . I n t r a u m a t i c d i s l o c a t i o n s , a d h e ­

s i o n s a n d f i x a t i o n s a r e v e r y c o m m o n .

I f r e a p p r o x i m a t i o n i s n o t p o s s i b l e , o r i n t e r p o s i n g

b o n e o r c a r t i l a g e i n l e n t i c u l a r e r o s i o n d o e s n o t suf ­

f i ce , t h e r e a r e a l t e r n a t i v e s :

1 . I n c u s t r a n s p o s i t i o n . A s m a l l a t t i c o t o m y i s d o n e ,

a n d t h e i n c u s i s c a r e f u l l y s e p a r a t e d f r o m t h e m a l l e u s .

I t i s s h a p e d b y r e m o v i n g t h e l o n g p r o c e s s , a n d a

n o t c h for t h e s t a p e s h e a d i s m a d e a t t h e e n d o f t h e

s h o r t p r o c e s s . T h e a r t i c u l a t i n g s u r f a c e i s e n l a r g e d t o

a c c e p t t h e m a l l e u s h a n d l e ( F i g . 1 2 - 1 4 / 1 ) .

2 . U s e o f t h e m a l l e u s h e a d . O n c e t h e h e a d i s

r e m o v e d , t h e s i t u a t i o n i s a s d e s c r i b e d for f i x a t i o n o f

t h e h e a d o f t h e m a l l e u s . T h e s a m e p r o c e d u r e s a p p l y ,

e x c e p t t h a t i f t h e m a l l e u s i s m o b i l e a n d t h e h e a d

i t s e l f i s n o t u s e d ( a n d a n y o f t h e o t h e r a l t e r n a t i v e s

a r e n o t p r e f e r r e d ) , t h e m a l l e u s h e a d i s lef t i n p l a c e

a n d o n l y t h e i n c u s i s r e m o v e d .

I n t h e c a s e o f a m i s s i n g i n c u s , t h e s e c o n d a l t e r ­

n a t i v e r e m a i n s v a l i d . I n all o f t h e s e p r o c e d u r e s ,

a l l o g e n e i c ( a l l o g r a f t ) o s s i c l e s a n d c a r t i l a g e a r e a l s o a

g o o d a l t e r n a t i v e

A n o t h e r m e t h o d i s t o u s e a n i n t e r p o s i t i o n p r o s ­

t h e s i s m a d e o f h y d r o x y a p a t i t e . A p o c k e t i s c r e a t e d

b e t w e e n t h e m a l l e u s a n d t h e o v e r l y i n g m e m b r a n e .

T h e l a r g e e n d o f t h e p r o s t h e s i s i s p l a c e d o v e r t h e

h e a d o f t h e s t a p e s a n d t h e d i s t a l ( t h i n ) e n d i n t h i s

n e w l y c r e a t e d p o c k e t ( F i g . 1 2 - 1 4 B ) . T h e a d v a n t a g e

i s t h a t s t a b i l i t y i s p r o v i d e d b y u t i l i z i n g b o t h t h e

t y m p a n i c m e m b r a n e a n d m a l l e u s h a n d l e , w i t h n o

c o n n e c t i o n t o t h e b o n y a n n u l u s o r fac ia l r i d g e . T h i s

i s a c l e v e r p r o s t h e s i s ( w h i c h st i l l m u s t s t a n d t h e t e s t

o f t i m e , h o w e v e r ) . I t m u s t b e m e n t i o n e d , h o w e v e r ,

t h a t d r i l l i n g i n i t i s n o t s o s i m p l e a s s u g g e s t e d

P a t i e n c e , c a r e f u l n e s s , a n d c o p i o u s i r r i g a t i o n a r e r e c ­

o m m e n d e d . A n a d d i t i o n a l p r o s t h e s i s o f t h i s s a m e

m a t e r i a l ( t h e W e h r s i n c u s p r o s t h e s i s ) fulf i l ls v e r y

n i c e l y t h e f u n c t i o n o f a s c u l p t u r e d i n c u s b e t w e e n t h e

m a l l e u s a n d s t a p e s h e a d w i t h o u t t h e d r i l l i n g a n d

s c u l p t u r i n g o f t h e i n c u s . T h i s t o o m u s t b e e v a l u a t e d

o v e r t i m e .

Stapes

F i x a t i o n o f t h e s t a p e s b y o t o s c l e r o s i s i s d e a l t w i t h

i n C h a p t e r 1 3 . F i x a t i o n r e l a t e d t o i n f l a m m a t i o n (fi­

b r o s i s ) o r t y m p a n o s c l e r o s i s i s r a r e i n a n i s o l a t e d f o r m

( t h a t i s , n o t a f f e c t i n g o t h e r o s s i c l e s a t t h e s a m e t i m e ) .

I n t h e s e e x c e p t i o n a l c a s e s , a s t a p e d e c t o m y wi l l suf ­

fice a n d t h e r e s u l t s s h o u l d b e a s g o o d a s i n o t o s c l e ­

r o s i s . H o w e v e r , i t i s e s s e n t i a l t o d o t h i s s t a p e d e c t o m y

in a " d r y e a r " a n d a s a s i n g l e p r o c e d u r e . I t s h o u l d

n o t b e p e r f o r m e d i n c o n j u n c t i o n w i t h a t y m p a n o ­

p l a s t y b e c a u s e o f a h i g h r i s k o f s e n s o r y h e a r i n g l o s s .

I f a t y m p a n o p l a s t y i s p e r f o r m e d , t h e s t a p e d e c t o m y

i s d e l a y e d . C a r e f u l s t a g i n g i s c r u c i a l .

F r a c t u r e s o f t h e c r u r a a r e t r e a t e d w i t h a p i s t o n

p r o s t h e s i s f r o m t h e i n c u s t o t h e o v a l w i n d o w , u n l e s s

t h e f r a c t u r e i s t h e r a r e o n e t h a t a l l o w s a c r u r o t o m y .

A g a i n , t h e s e p r o c e d u r e s a r e d o n e i n a " d r y e a r . " I n

c a s e s o f f r a c t u r e d c r u r a a n d f o o t p l a t e , i t i s s a f e r t o

r e m o v e t h e f o o t p l a t e a n d u s e c o n n e c t i v e t i s s u e t o

s e a l t h e w i n d o w . ( A w i r e c o n n e c t i v e t i s s u e p r o s t h e s i s

i s p r e f e r r e d b u t i t i s n o t e s s e n t i a l . ) A n a l t e r n a t i v e i n

f r a c t u r e d c r u r a a n d i n t a c t m o b i l e f o o t p l a t e i s t h e u s e

o f a n i n v e r t e d a l l o g r a f t s t a p e s ( F i g . 1 2 - 1 4 C ) .

Combined Ossicular Problems

R e p a i r s b e c o m e m o r e t r o u b l e s o m e i f t h e m a l l e u s

h a n d l e o r s t a p e s ( o r b o t h ) a r e a b s e n t . T h i s m e a n s

t h a t t h e p r o s t h e s i s m u s t b e s u p p o r t e d b y t h e g r a f t e d

t y m p a n i c m e m b r a n e , w h i c h c a r r i e s a h i g h e r r i s k o f

f a i l u r e , o r a l o n g e r p r o s t h e s i s m u s t b e u s e d f r o m t h e

t y m p a n i c m e m b r a n e t o t h e o v a l w i n d o w .

F i x a t i o n o f t h e h e a d o f t h e m a l l e u s a s s o c i a t e d w i t h

a f i x e d s t a p e s f o o t p l a t e h a s b e e n s h o w n t o b e re ­

p a i r e d w i t h a m a l l e u s - t o - o v a l - w i n d o w w i r e c o n n e c ­

t ive t i s s u e p r o s t h e s i s . W h i l e t h i s i s a g o o d a l t e r n a t i v e ,

i t h a s t h e d r a w b a c k s o f l a t e r a l i z a t i o n a n d l o s s o f

a d e q u a t e c o n d u c t i v i t y . I t m u s t b e r e m e m b e r e d t h a t

w h e n e v e r t h e s t a p e s f o o t p l a t e i s r e m o v e d , a f i s tu l a

o f t h e o v a l w i n d o w i s a p o t e n t i a l c o m p l i c a t i o n . R e ­

g a r d l e s s o f t h e g ra f t o r p r o s t h e s i s , a n a d e q u a t e s ea l

i s e s s e n t i a l . A l t e r n a t i v e s i n c l u d e t h e u s e o f a T O R P ,

a T O R P - s h a p e d c o r t i c a l b o n e o s s i c l e , c a r t i l a g e , o r

c e r a m i c p r o s t h e s i s , o r a s c u l p t u r e d o s s i c l e ( a u t o l o ­

g o u s o r a l l o g e n e i c ) .

I n c a s e s o f f i x a t i o n o f t h e o s s i c u l a r c h a i n b y t y m ­

p a n o s c l e r o s i s , t h e f irst s t a g e i m p l i e s m o b i l i z a t i o n ,

c o m p l e t i o n o f t h e m a l l e u s , d i s a r t i c u l a t i o n o f t h e

i n c u s , a n d S J o n . T h i s p r e p a r e s for a s e c o n d p r o c e ­

d u r e i n w h i c h t h e s t a p e d e c t o m y i s d o n e . S u r g i c a l

r e p a i r i n v o l v e s t h e a l t e r n a t i v e s d e s c r i b e d b e l o w .

W h e n b o t h t h e m a l l e u s a n d i n c u s a r e a b s e n t

( u s u a l l y s e e n i n c h r o n i c o t i t i s m e d i a c a s e s , a n d n o t

u n c o m m o n l y i n t y m p a n o m a s t o i d e c t o m y p r o c e ­

d u r e s ) , o r w h e n b o t h o s s i c l e s a r e a s i n g l e , c o n g e n i t a l ,

n o n f u n c t i o n a l " m a s s , " t h e a l t e r n a t i v e s a r e a c l a s s i c

t y p e III t y m p a n o p l a s t y o r u s e o f a s h o r t p r o s t h e s i s

o r g ra f t ( d e s c r i b e d a b o v e ) , i f t h e s t a p e s i s i n t a c t a n d

m o b i l e . I f t h e s t a p e s i s f i xed o r d a m a g e d , a l o n g

p r o s t h e s i s ( t y m p a n i c m e m b r a n e t o f o o t p l a t e o r o v a l

w i n d o w g r a f t ) i s n e c e s s a r y

T y m p a n o p l a s t y 243

I f t h e m a l l e u s i s a b s e n t a n d t h e r e i s a n i n t a c t a n d

m o b i l e s t a p e s , a s h o r t p r o s t h e s i s i s u s e d . H o w e v e r ,

a l o n g p r o s t h e s i s i s i n d i c a t e d i f t h e s t a p e s i s d a m a g e d

( F i g . 1 2 - 1 4 E ) .

I n c a s e s o f t y m p a n o m a s t o i d e c t o m y , t h e c o n c e p t

o f s p a c e b e c o m e s r e l e v a n t i n t e r m s o f r e c o n s t r u c t i o n

A t t h i s p o i n t a n d w i t h t h i s t y p e o f d i s e a s e , a n i n t a c t -

b r i d g e t y m p a n o m a s t o i d e c t o m y m a k e s g o o d s e n s e ( i f

n e e d e d , o f c o u r s e ; i f p o s s i b l e , a n i n t a c t - w a l l p r o c e ­

d u r e i s p r e f e r r e d ) .

A s m e n t i o n e d e a r l i e r , a c r i t i ca l f a c t o r i s t h e p r e s ­

e n c e o r a b s e n c e o f t h e m a l l e u s h a n d l e . A n e q u a l l y

i m p o r t a n t f a c t o r ( s o m e t i m e s o v e r l o o k e d ) i s t h e p r e s ­

e n c e o r a b s e n c e o f a m o b i l e f o o t p l a t e . F o r p r a c t i c a l

p u r p o s e s , t h e u s e o f a T O R P wi l l b e d e s c r i b e d ,

f o l l o w e d b y o t h e r a l t e r n a t i v e s .

Placement of a TORP

T w o p o i n t s o f c o n t a c t a r e c r u c i a l . T h e u s u a l t e n -

d e h c y . i s . t o t h i n k i n t e r m s o f e x t r u s i o n a n d f o r g e t t h e

d i s t a l e n d o f t h e T O R P ( o v e r t h e f o o t p l a t e o r o v a l

w i n d o w g r a f t ) .

T h e T O R P i s c u t t o t h e n e c e s s a r y l e n g t h . T h i s m a y

b e 3 . 5 m m for a n o p e n c a v i t y , 4 m m i f t h e m a l l e u s

h a n d l e i s p r e s e n t , o r 5 m m i f i t i s a b s e n t .

A t h i n b u t l a r g e p i e c e o f c a r t i l a g e i s p l a c e d o v e r

t h e T O R P ( b e n e a t h t h e m a l l e u s o r t y m p a n i c m e m ­

b r a n e g r a f t ) t o p r o v i d e p r o t e c t i o n f r o m e x t r u s i o n

( s o m e s u r g e o n s s u t u r e i t t o t h e T O R P ) . I f t h e r e i s a

f o o t p l a t e o r m e m b r a n e , t h e T O R P i s p l a c e d o v e r i t

a n d i s s u p p o r t e d w i t h a b u n d a n t G e l f o a m t o s e c u r e

i t i n p o s i t i o n . A T O R P w i t h a p e g c a n b e u s e d t o

p r o v i d e m o r e s t a b i l i t y a t t h e f o o t p l a t e a n d p r e v e n t

s l i p p i n g ( F i g . 1 2 - 1 5 A ) . O n c e t h e T O R P i s p l a c e d , i t

s h o u l d i m p a r t s o m e t e n s i o n t o t h e t y m p a n i c m e m ­

b r a n e . A T O R P - s h a p e d p i e c e o f c a r t i l a g e o r c o r t i c a l

b o n e c a n b e u s e d , a s w e l l . A s m a l l p i e c e o f S i l a s t i c

c a n b e p l a c e d , s u r r o u n d i n g t h e p r o s t h e s i s a t t h e o v a l

w i n d o w a r e a , i n o r d e r t o p r e v e n t a d h e s i o n s ( F i g . 1 2 -

1 5 C ) . A c e r a m i c T O R P c a n a l s o b e u s e d ( F i g . 1 2 -

1 5 D ) , a s w e l l a s a s c u l p t u r e d i n c u s . T h e l a t t e r s h o u l d

b e f l a t t e n e d t o w a r d t h e t y m p a n i c m e m b r a n e i n o r d e r

t o p r o v i d e a s m o o t h a n d w i d e c o n t a c t . I f t h e m a l l e u s

h a n d l e i s p r e s e n t , d r i l l i n g a g r o o v e i n t h e T O R P

p r o v i d e s b e t t e r s t a b i l i t y . W h e n e v e r a l o n g p r o s t h e s i s

( T O R P t y p e ) i s p l a c e d o v e r a n o v a l w i n d o w w i t h o u t

a f o o t p l a t e , t h e r e i s a p o s s i b i l i t y o f a f i s t u l a a n d g o o d

s e a l i s n e e d e d . I f t h e r e i s a p o t e n t i a l f o r r e t r a c t i o n

( for e x a m p l e , e u s t a c h i a n t u b e d y s f u n c t i o n ) , t h e s e

p r o s t h e s e s m a y l e a d t o f i s t u l i z a t i o n b y s l i d i n g i n t o

t h e o v a l w i n d o w .

Pertinent Histopathology

F I G U R E S 1 2 - 1 6 T O 1 2 - 1 8

C h r o n i c o t i t i s m e d i a w i t h p e r f o r a t i o n o f t h e t y m ­

p a n i c m e m b r a n e . T h e l o w e r m a g n i f i c a t i o n ( F i g . 1 2 -

1 6 ) s h o w s t h e t h r e e l a y e r s o f t h e t y m p a n i c m e m ­

b r a n e ; ( 1 ) t h e o u t e r e p i t h e l i u m ( s t r a t i f i e d s q u a m o u s

e p i t h e l i u m ) , c o n t i n u o u s w i t h t h a t o f t h e e x t e r n a l e a r

c a n a l ; ( 2 ) t h e m i d d l e e a r c o n n e c t i v e t i s s u e l a y e r ,

c o n t i n u o u s w i t h b o t h t h e c o n n e c t i v e t i s s u e l a y e r o f

t h e e x t e r n a l e a r c a n a l a n d m i d d l e e a r ; a n d ( 3 ) t h e

i n n e r m u c o s a l l a y e r , c o n t i n u o u s w i t h t h a t o f t h e

m i d d l e e a r . T h e h i g h e r m a g n i f i c a t i o n s ( F i g s , 1 2 - 1 7 ,

1 2 - 1 8 ) c l e a r l y s h o w t h e i n g r o w t h o f o u t e r s t r a t i f i e d

s q u a m o u s e p i t h e l i u m (arrows). T h i s e p i t h e l i u m i s

r e m o v e d b e f o r e p l a c e m e n t o f a c o n n e c t i v e t i s s u e

g ra f t ; o t h e r w i s e t h e r e wi l l b e n o m i g r a t i o n o f e p i t h e ­

lial c e l l s o v e r t h e g ra f t . T h e p u r p o s e o f t h e g ra f t i s

t o " r e p l a c e " t h e l o s t c o n n e c t i v e t i s s u e a n d t o s e r v e

a s a b r i d g e for m i g r a t i o n o f e p i t h e l i a l c e l l s t o c l o s e

t h e g a p ( p e r f o r a t i o n ) . T h e s e p h o t o m i c r o g r a p h s i l l u s ­

t r a t e t h e c o n c e p t s o f p e r f o r a t i o n a n d g r a f t i n g ; t h e y

a r e n o t m e a n t t o i m p l y o r t o s u g g e s t g r a f t i n g a

p e r f o r a t i o n d u r i n g a n a c u t e e p i s o d e o f o t i t i s m e d i a ,

e v e n i f s u p e r i m p o s e d o v e r a c h r o n i c p r o c e s s .

245Tympanoplasty

,"""

External ear canal

FIGURE 12-17.

.~

.) EXlerna! ear canal

244 Tympnnoplasty

246 T y m p a n o p l a s t y

FIGURE 12-1K

CHAPTER 13

Surgery for Stapes Fixation

S t a p e s p r o c e d u r e s a i m t o r e - e s t a b l i s h s o u n d t r a n s ­

m i s s i o n t h r o u g h a s t i f f e n e d o s s i c u l a r c h a i n , s e c o n ­

d a r y to' f i x a t i o n o f t h e s t a p e s . T h e s e p r o c e d u r e s

i n v o l v e p a r t i a l o r t o t a l r e m o v a l o f t h i s o s s i c l e a n d

r e p l a c e m e n t w i t h m o b i l e p o r t i o n s o f i t o r w i t h a

p r o s t h e s i s .

T w o s u r g i c a l p r o c e d u r e s t h a t h a v e b e e n u s e d

s u c c e s s f u l l y f o r s t a p e s f i x a t i o n wi l l n o t b e d i s c u s s e d

a t l e n g t h h e r e . A l t h o u g h a d e t a i l e d d e s c r i p t i o n i s

b e y o n d t h e s c o p e o f t h i s a t l a s , t h e r e a d e r s h o u l d b e

a w a r e o f t h e m . T h e y a r e ( 1 ) f e n e s t r a t i o n o f t h e l a t e r a l

s e m i c i r c u l a r c a n a l , a n d ( 2 ) s o n o i n v e r s i o n . F e n e s t r a ­

t ion o f t h e l a t e r a l s e m i c i r c u l a r c a n a l a l l o w s v i b r a t i o n s

t o r e a c h t h e h a i r c e l l s t h r o u g h t h e s c a l a v c s t i b u l i ,

b y p a s s i n g t h e o s s i c u l a r c h a i n , w i t h a r e s u l t a n t m i l d

a i r - b o n e g a p o f 2 5 t o 3 0 dF3. A l t h o u g h t h i s p r o c e d u r e

h a s b e e n r e p l a c e d b y s t a p e d e c t o m y , i t s h o u l d b e

k e p t i n m i n d . I t c a n b e o f u s e i n s o m e u n u s u a l c a s e s

o f o t o s c l e r o s i s , a s a n i n t e r v a l o p e r a t i o n i n s o m e f o r m s

o f t y m p a n o p l a s t y , a n d c o u l d e v e n t u a l l y r e - e m e r g e

a s a s u r g i c a l t e c h n i q u e for d e l i v e r y o f d r u g s t o t h e

i n n e r e a r . S o n o i n v e r s i o n ( t e c h n i q u e o f G a r c i a - I b a n e z )

d e l i v e r s v i b r a t o r y s t i m u l a t i o n t h r o u g h t h e r o u n d

w i n d o w m e m b r a n e b y u t i l i z i n g a p r o s t h e s i s f r o m t h e

i n c u s o r m a l l e u s t o t h e r o u n d w i n d o w . T h e n o r m a l

m e c h a n i s m o f s o u n d t r a n s m i s s i o n v i a t h e o s s i c u l a r

c h a i n t o t h e o v a l w i n d o w i s s u c c e s s f u l l y " i n v e r t e d . "

T h e b a s i c h e a d p o s i t i o n w i t h s l i g h t h y p e r t e n s i o n

a n d t h e t r a n s c a n a l a p p r o a c h h a v e a l r e a d y b e e n d e ­

s c r i b e d ; t h e d i s c u s s i o n wi l l f o c u s o n p r o c e d u r e s a f t e r

t h e a n n u l u s h a s b e e n e l e v a t e d .

S t a p e s p r o c e d u r e s g e n e r a l l y a r e d o n e u n d e r l oca l

a n e s t h e s i a w i t h s e d a t i o n . G e n e r a l a n e s t h e s i a a l s o

c a n b e u s e d ; h o w e v e r , i t h a s t h e d i s a d v a n t a g e o f

p r e v e n t i n g t h e s u r g e o n f r o m m o n i t o r i n g v e s t i b u l a r

s y m p t o m s o r h e a r i n g g a i n s i n t h e o p e r a t i n g r o o m .

S o m e s u r g e o n s p r e f e r a s m a l l e n d a u r a l a p p r o a c h ,

s i n c e i t p r o v i d e s g o o d e x p o s u r e a n d a l l o w s b i m a n u a l

s u r g e r y w i t h o u t t h e n e e d fo r s p e c u l u m h o l d e r s ;

h o w e v e r , s p e c u l u m h o l d e r s a r e u s e d b y a m a j o r i t y

o f s u r g e o n s . Tjhe a u t h o r s p r e f e r a t r a n s c a n a l a p ­

p r o a c h , u s i n g a n e a r s p e c u l u m w i t h o u t a h o l d e r . A

w e l l - f i t t e d e a r s p e c u l u m h o l d s i n p l a c e q u i t e w e l l . I t

i s n o t h a r d t o s t a b i l i z e t h e s p e c u l u m w i t h t h e left

h a n d ( fo r a r i g h t - h a n d e d s u r g e o n ) , w h i l e u s i n g a n

i n s r u m e n t ( s u c h a s a s u c t i o n t i p ) a t t h e s a m e t i m e .

T h e p r o c e d u r e c a n b e s t a r t e d w i t h a s m a l l e r s p e c ­

u l u m ; o n c e t h e i n c i s i o n s h a v e b e e n m a d e , a t i g h t l y

f i t t ing o n e i s u s e d .

S m a l l e x o s t o s e s o f t h e c a n a l ( i f a n y ) a r e r e m o v e d .

(If t h e y a r e l a r g e o r i f a c a n a l p l a s t y i s n e c e s s a r y , t h i s

s h o u l d b e d o n e a s a s e p a r a t e p r o c e d u r e a n d t h e

s t a p e d e c t o m y d e l a y e d u n t i l c o m p l e t e h e a l i n g h a s

b e e n a c h i e v e d , w h i c h c o u l d b e a m a t t e r o f m o n t h s . )

I t s h o u l d b e r e m e m b e r e d t h a t e n t r a n c e t o t h e m i d d l e

e a r m u s t b e m a d e i n a d r y f i e ld a n d b e n e a t h t h e

a n n u l u s . F r o m t h i s p o i n t o n , t h e m i c r o s c o p e i s u s e d

a t a m a g n i f i c a t i o n o f a t l e a s t 1 0 x . I n g e n e r a l t e r m s

t h e r e a r e t h r e e b a s i c t y p e s o f s t a p e d e c t o m y — p a r t i a l ,

t o t a l , a n d p i s t o n . T h e p r o c e d u r e h e r e wi l l b e a

g e n e r a l a p p r o a c h , a n d t h e d i f f e r e n t t y p e s wi l l b e

d e s c r i b e d o n t h e b a s i s o f t h e f i n d i n g s a n d t h e i r

i n d i c a t i o n s

O n c e t h e a n n u l u s i s e l e v a t e d , t h e f irst o b j e c t i v e i s

t o o b t a i n a d e q u a t e e x p o s u r e a n d t h e n t o e x p l o r e t h e

e a r . W o r k o n t h e s t a p e s i s t h e f i n a l s t e p , a n d i s o n l y

b e g u n a f t e r a l l o t h e r w o r k i s c o m p l e t e d . A u s e f u l

r u l e o f t h u m b for e x p o s u r e o f t h e o v a l w i n d o w i s t o

a c h i e v e c l e a r v i s u a l i z a t i o n o f t h e p y r a m i d a l e m i n e n c e

a n d t h e s u p e r i o r a s p e c t o f t h e fac ia l n e r v e . M o s t o f

t h e t i m e , t h i s r e q u i r e s r e m o v a l o f b o n e f r o m t h e

p o s t e r i o r c a n a l ; i n d o i n g s o , t h e c h o r d a t y m p a n i

S u r g e r y for S t a p e s F i x a t i o n 249

m u s t b e f r e e d . U s u a l l y a f i n e n e e d l e c a n b e u s e d t o

m o b i l i z e t h e c h o r d a a n t e r i o r l y t o w a r d t h e i n c u s ( F i g .

1 3 - 1 / 1 ' ) . I f t h e c h o r d a wi l l b e s t r e t c h e d b y t h i s

m a n e u v e r , i t i s b e t t e r t o s e c t i o n i t s h a r p l y w i t h a

k n i f e o r a B e l l u c c i s c i s s o r s ( F i g . 1 3 - 1 / 1 ) .

B o n e o f t h e p o s t e r i o r c a n a l c a n b e d r i l l e d o r

c u r e t t e d . T h e a u t h o r s p r e f e r t o c u r e t i t w i t h l a r g e

s t a p e s c u r e t s i n s t r o k e s a w a y f r o m t h e o s s i c l e s

( a v o i d i n g l u x a t i o n o f t h e o s s i c l e s ) . M e t i c u l o u s re ­

m o v a l o f b o n e c h i p s s h o u l d b e d o n e ( F i g . 1 3 - 1 B ) .

O n c e v i s u a l i z a t i o n h a s b e e n a c h i e v e d , all a n a t o m i c

l a n d m a r k s a r e i n s p e c t e d ( F i g . 1 3 - 1 Q .

T h e p r e s e n c e o f a n o p e n r o u n d w i n d o w i s i m p o r ­

t a n t . T o t a l o b l i t e r a t i o n wi l l l e a d t o a p o o r e r r e s u l t .

D r i l l i n g a r o u n d w i n d o w a l s o l e a d s t o p o o r r e s u l t s

a n d c o m p l i c a t i o n s a n d i s n o t r e c o m m e n d e d . A v e r y

s m a l l o p e n i n g (»70/ s u r g i c a l l y i n d u c e d ) i n t h e w i n d o w

s h o u l d s u f f i c e for a s a t i s f a c t o r y o u t c o m e ; t h i s s h o u l d

b e k e p t i n m i n d . H o w e v e r , i n s o m e p a t i e n t s w i t h

o b l i t e r a t e d r o u n d w i n d o w s s o m e g a i n i n h e a r i n g c a n

b e o b t a i n e d ; s i n c e s u c h a n i m p r o v e m e n t m i g h t m a k e

a s i g n i f i c a n t d i f f e r e n c e in t h e i r l i v e s , a s t a p e d e c t o m y

s h o u l d b e a t t e m p t e d .

T h e o s s i c u l a r c h a i n i s t h e n p a l p a t e d ( u s i n g a n

a n g l e d h o o k o r H o u g h h o e ) i n o r d e r t o l o c a t e p o i n t s

o f o s s i c u l a r f i x a t i o n ( F i g . 1 3 - 1 D , E ) . S p e c i a l a t t e n t i o n

i s p a i d t o c a s e s o f u n i l a t e r a l h e a r i n g l o s s , i n w h i c h

n o n o t o s c l e r o t i c f i x a t i o n s a r e m o r e f r e q u e n t . F i x a t i o n

o f t h e m a l l e u s m o s t o f t e n i s c o n g e n i t a l , a n d t h e

f i x a t i o n i s a t t h e h e a d . T h i s f i n d i n g r e q u i r e s a n

a t t i c o t o m y ( p r e v i o u s l y d e s c r i b e d ) a n d e x p o s u r e o f

t h e h e a d o f t h e m a l l e u s ( F i g . 1 3 - 2 / 1 ) . T h e a u t h o r s

p r e f e r t o u s e c u r e t s , b u t i f a d r i l l i s u s e d , t h e i n c u s

s h o u l d b e s e p a r a t e d f r o m t h e h e a d o f t h e s t a p e s w i t h

a j o i n t k n i f e i n o r d e r t o a v o i d a c o u s t i c t r a u m a .

A t t a c h m e n t s c a n s o m e t i m e s b e r e l e a s e d , a n d s m a l l

p i e c e s o f S i l a s t i c c a n b e p l a c e d t o a v o i d f i x a t i o n ( F i g .

1 3 - 2 6 ) ; h o w e v e r , u n l e s s t h e a t t a c h m e n t s a r e m i n i ­

m a l , t h i s i s u s u a l l y f o l l o w e d b y r e f i x a t i o n . A s o l i d

f i x a t i o n r e q u i r e s r e m o v a l o f t h e h e a d o f t h e m a l l e u s

w i t h m a l l e u s n i p p e r s ( F i g . 1 3 - 2 C ) a n d p l a c e m e n t o f

a m a l l e u s t o o v a l w i n d o w p r o s t h e s i s , a b o n e s t r u t ,

o r a t o t a l o s s i c u l a r r e p l a c e m e n t p r o s t h e s i s ( T O R P )

( F i g . 1 3 - 2 D - F ) . ( S e e a l s o C h a p t e r 1 4 for a l t e r n a t i v e

p r o c e d u r e s u t i l i z i n g a l a s e r . )

U n d e r 10 X o r 16 x m a g n i f i c a t i o n , t h e o v a l

w i n d o w a n d s t a p e s a r e i n s p e c t e d ( F i g . 1 3 - 3 ) . I s t h e r e

a n o r m a l - s i z e d o v a l w i n d o w , a p r o m o n t o r y o v e r ­

h a n g , o r a d e h i s c e n t f ac i a l n e r v e ? I s t h e f ac i a l n e r v e

o v e r t h e f o o t p l a t e ? I s t h e r e a p e r s i s t e n t s t a p e d i a l

a r t e r y ? I s t h e s t a p e s f i x e d a n t e r i o r l y o r p o s t e r i o r l y ?

I s t h e f o o t p l a t e o f n o r m a l s i z e ( o n a v e r a g e , 1 .4 m m

w i d e a n d 3 . 0 m m l o n g ) ? I s p a r t , h a l f , o r a l l o f t h e

f o o t p l a t e i n v o l v e d ? I s t h e r e o b l i t e r a t i o n o f t h e foo t ­

p l a t e a n d w i n d o w b y o t o s c l e r o t i c f o c i ?

O n t h e b a s i s o f t h e s e o b s e r v a t i o n s a n d t h e p re f ­

e r e n c e a n d e x p e r i e n c e o f t h e s u r g e o n , t h e s p e c i f i c

s u r g i c a l p r o c e d u r e i s s e l e c t e d . R e g a r d l e s s o f t h e

p r o c e d u r e , t h e u n d e r l y i n g i d e a i s t h a t all o r p a r t o f

t h e f o o t p l a t e i s t o b e r e m o v e d , a n d a m e m b r a n e

( p r e f e r a b l y c o l l a g e n o u s ) u s e d i n i ts p l a c e for a s e a l .

I f a p r o s t h e s i s wi l l be e m p l o y e d , a f i rm a n d l a s t i n g

c o n t a c t m u s t b e e s t a b l i s h e d w i t h t h e l o n g p r o c e s s o f

t h e i n c u s ( o r t h e m a l l e u s h a n d l e ) .

Total Stapedectomy with Prosthesis

T h e c l a s s i c t o t a l s t a p e d e c t o m y i s u s e d h e r e a s t h e

p r i m a r y p r o c e d u r e t o d e s c r i b e g e n e r a l p r i n c i p l e s a n d

p r o b l e m s e n c o u n t e r e d d u r i n g s u r g e r y . T h e d e s c r i p ­

t ion a s s u m e s t h a t t h e r e i s n o n o b l i t e r a t i v e f i x a t i o n o f

t h e s t a p e s , t h e r e s t o f t h e o s s i c l e s a r e m o b i l e , t h e

r o u n d w i n d o w i s p a t e n t , a n d t h e o v a l w i n d o w i s o f

n o r m a ! s i z e . T h e d i s t a n c e b e t w e e n t h e i n c u s a n d t h e

f o o t p l a t e i s m e a s u r e d . T h e a v e r a g e m e a s u r e m e n t

f r o m t h e h e a d o f t h e s t a p e s t o t h e f o o t p l a t e i s 3 . 2 9

m m ± 0 . 1 5 m m , t o w h i c h i s a d d e d 1 m m o f t h e

l e n t i c u l a r p r o c e s s . T h e a v e r a g e l e n g t h o f a p r o s t h e s i s

i s 4 . 0 m m i n w o m e n a n d 4 . 2 5 t o 4 . 5 0 m m i n m e n . I f

a w i r e c o n n e c t i v e t i s s u e p r o s t h e s i s i s t o b e u s e d , i t

s h o u l d b e m a d e a t t h i s t i m e . C o n n e c t i v e t i s s u e

s h o u l d b e h a r v e s t e d a t t h i s p o i n t a s w e l l .

Harvesting a Graft

O n c e t h e s t a p e s h a s b e e n r e m o v e d , t h e v e s t i b u l e

i s e x p o s e d a n d a n e w m e m b r a n e i s n e e d e d t o s e a l

t h e o p e n i n g . C o n n e c t i v e t i s s u e , s p e c i f i c a l l y c o l l a g e n ,

a l l o w s t h e f o r m a t i o n o f a s t a b l e s e a l t h a t b e c o m e s

p a r t o f t h e w i n d o w . W h i l e G e l f o a m s t i m u l a t e s t i s s u e

g r o w t h a n d i s u s e d s a t i s f a c t o r i l y b y m a n y s u r g e o n s ,

t h e s e m e m b . a n e s t e n d t o b e t h i n a n d c a r r y a h i g h e r

r i s k o f f i s t u l a f o r m a t i o n a n d p e r i l y m p h l e a k a g e . Dif­

f e r e n t s o u r c e s a r e u s e d , s u c h a s fat a n d c o n n e c t i v e

t i s s u e f r o m t h e e a r l o b e o r p o s t a u r i c u l a r a r e a , t r a g a l

p e r i c h o n d r i u m , o r a v e i n . T i s s u e f r o m t h e e a r l o b e

a n d p o s t a u r i c u l a r a r e a i s u s e d for w i r e c o n n e c t i v e

t i s s u e p r o s t h e s e s , a n d f r o m p e r i c h o n d r i u m o r v e i n

a s s e a l i n g m e m b r a n e s w i t h s i m p l e w i r e s o r p i s t o n s .

T y p e o f p r o s t h e s i s , e a s e o f h a n d l i n g , a n d i n d i v i d u a l

p r e f e r e n c e s wi l l d e t e r m i n e s u c h c h o i c e s

A s m a l l i n c i s i o n s u f f i c e s for h a r v e s t i n g t i s s u e f r o m

t h e e a r l o b e o r p o s t a u r i c u l a r a r e a ( F i g . 13-4A, 6 ) . T h e

i n c i s i o n i s c l o s e d w i t h o n e o r t w o a p p r o p r i a t e s u t u r e s

250 S u r g e r y for S t a p e s F i x a t i o n

FIGURE 13-2.

S u r g e r y for S t a p e s F i x a t i o n 2 5 1

FIGURE 13-3.

S u r g e r y for S t a p e s F i x a t i o n 253

a n d t h e t i s s u e i s left i n s a l i n e s o l u t i o n . T r a g a l p e r i ­

c h o n d r i u m i s o b t a i n e d v ia a s m a l l i n c i s i o n in t h e

u n d e r s u r f a c e o f t h e t r a g u s , e x p o s i n g t h e p e r i c h o n ­

d r i u m , w h i c h c a n b e p e e l e d off t h e u n d e r l y i n g c a r ­

t i l age ( F i g . 1 3 - 4 C ) . M e t i c u l o u s h e m o s t a s i s i s d o n e ,

t h e i n c i s i o n i s c l o s e d w i t h t w o o r t h r e e a p p r o p r i a t e

s u t u r e s , a n d t h e p e r i c h o n d r i u m i s g e n t l y p r e s s e d

a n d r i n s e d i n s a l i n e . All i n s t r u m e n t s a n d m a t e r i a l s

u s e d i n th i s a r e a s h o u l d b e r i n s e d i n o r d e r t o r e m o v e

a n y p a r t i c l e s f r o m t h e i r s u r f a c e s .

V e i n c a n b e h a r v e s t e d f r o m t h e d o r s u m o f t h e

h a n d b y a s m a l l i n c i s i o n . B o t h e n d s a r e c a r e f u l l y

t i ed; t h e m i d s e c t i o n o f t h e v e i n ( s i z e a s n e e d e d ) i s

r e m o v e d a n d spl i t o p e n , t h e e n d o t h e l i a l l a y e r i s

r e m o v e d , a n d t h e v e i n i s p r e s s e d a n d r i n s e d i n s a l i n e

(F ig . 1 3 - 4 D ) . I n g e n e r a l , t h e a d v e n t i t i a l l a y e r i s

p l a c e d f a c i n g t h e v e s t i b u l e . W i t h p e r i c h o n d r i u m , t h e

s i d e i n d i r e c t c o n t a c t w i t h t h e c a r t i l a g e i s p l a c e d

f a c i n g t h e m i d d l e e a r ; o t h e r w i s e s m a l l c a r t i l a g e r e m ­

n a n t s m a y fall i n t o t h e v e s t i b u l e , p o t e n t i a l l y c a u s i n g

c o m p l i c a t i o n s .

Making the Prosthesis

M a n y s a t i s f a c t o r y p r o s t h e s e s a r e c o m m e r c i a l l y

a v a i l a b l e . E x c e p t for p o l y e t h y l e n e s t r u t s a n d w i r e

C e l f o a m p r o s t h e s e s ( w h i c h t e n d t o h a v e a h i g h e r

i n c i d e n c e o f f i s t u l a e ) a n d P l a s t i p o r e p i s t o n s ( w h i c h

t e n d t o c a u s e loca l r e a c t i o n s ) , t h e v a s t m a j o r i t y o f

p r o s t h e s e s a r e s a t i s f a c t o r y i f p r o p e r l y u s e d . T h e i r

u s e will d e p e n d o n s u r g i c a l f i n d i n g s a n d t h e s u r ­

g e o n ' s p r e f e r e n c e a n d e x p e r i e n c e . B o t h w i r e a n d

c o n n e c t i v e t i s s u e a n d w i r e T e f l o n p i s t o n s c a n b e

m a d e a t s u r g e r y . T h e s e a r e t h e c l a s s i c p r o s t h e s e s

t h a t h a v e s t o o d t h e t e s t o f t i m e . T h e w i r e a n d

c o n n e c t i v e t i s s u e p r o s t h e s i s c a n b e t a i l o r e d t o t h e

n e e d e d l e n g t h o r b e n t o r c u r v e d i n n a r r o w w i n d o w s

o r p r o m i n e n t facial n e r v e s ; i t a l s o p r o v i d e s a n e x c e l ­

l ent s e a l .

T h e t e c h n i q u e for m a k i n g a n i n c u s - t o - o v a l w i n ­

d o w p r o s t h e s i s i s d e p i c t e d i n F i g u r e 1 3 - 5 . A p i e c e

of c o n n e c t i v e t i s s u e is c u t to a s i z e of 2 x 3 m m .

T h i s i s p l a c e d o n t h e e d g e o f t h e d i e a n d i s t i ed a t

its m i d p o r t i o n w i t h a 0 . 0 0 5 - m m s t a i n l e s s s t e e l w i r e

( F i g . 1 3 - 5 / 1 ) . A d r o p o f s a l i n e h e l p s h a n d l i n g a n d

p l a c i n g o f t h e t i s s u e i n t h e d e s i r e d p o s i t i o n . W i t h a n

a l l i g a t o r f o r c e p s h o l d i n g b o t h e n d s , t h e k n o t i s t ight ­

e n e d unt i l i t d i s a p p e a r s i n t o t h e c o n n e c t i v e t i s s u e

T h e w i r e i s l o o p e d a r o u n d t h e l a r g e r p o s t o f t h e d i e

w i t h t h e b o t t o m o f t h e c o n n e c t i v e t i s s u e a t 4 m m

(F ig . 1 3 - 5 8 ) . T h e c o n n e c t i v e t i s s u e e n d i s r o t a t e d

a r o u n d t h e s m a l l e r p o s t (F ig . 1 3 - 5 C ) . W i r e - c u t t i n g

s c i s s o r s a r e u s e d t o c u t t h e l o o p ( t o h o o k i n t o t h e

i n c u s ) l a r g e • o r s h o r t e r , a c c o r d i n g t o t h e s i z e o f t h e

l o n g p r o c e s s o f t h e i n c u s . T h e w i r e - c u t t i n g s c i s s o r s

a r e s l id u p t o t h e k n o t i n t h e m i d d l e o f t h e g r a f t a n d

t h e w i r e i s s e c t i o n e d . N o s h a r p e n d s s h o u l d b e left

u n l e s s t h e p a t i e n t h a s o t o s c l e r o s i s a s s o c i a t e d w i t h

e n d o l y m p h a t i c h y d r o p s ; i n th i s c a s e , a n e n d p u r ­

p o s e l y left s h a r p m i g h t w o r k a s a " c o n s e r v a t i v e

t a c k . " T h e p r o s t h e s i s i s left in s a l i n e unt i l u s e . A

5 - m m m a l l e u s - t o - o v a l w i n d o w p r o s t h e s i s i s s h o w n

i n F i g u r e 1 3 - 5 D .

T h e m a k i n g o f a w i r e p i s t o n i s s h o w n i n F i g u r e

1 3 - 6 ; t h e t e c h n i q u e ( a f t e r R o s a l e s ) i s s e l f - e x p l a n a t o r y

Procedure

T h e f o o t p l a t e i s f r a c t u r e d a t t h e m i d l i n e w i t h a

n e e d l e ( F i g . 1 3 - 7 4 ) . C r e a t i n g a h o l e i n t h e f o o t p l a t e

i s f r e q u e n t l y d e s c r i b e d , b u t for a to ta l s t a p e d e c t o m y

a n a c t u a l f r a c t u r e i s b e t t e r a n d p r e v e n t s a f loat ing

f o o t p l a t e . T h e m u c o s a i s n o t e l e v a t e d a t t h e f o o t p l a t e ;

t h i s a v o i d s b l e e d i n g a n d h e l p s t o p r e v e n t s m a l l , l o o s e

f r a g m e n t s f r o m fall ing i n t o t h e v e s t i b u l e . I f t h e r e i s

b l e e d i n g , s m a l l p i e c e s o f G e l f o a m s a t u r a t e d w i t h a

s o l u t i o n o f MOOO e p i n e p h r i n e a r e a p p l i e d t o p i c a l l y .

A N o . 2 4 s u c t i o n t ip w i t h t h e f i n g e r off t h e h o l e i s

u s e d . I t c a n n o t b e e m p h a s i z e d e n o u g h t h a t t h e

s u c t i o n t ip m u s t s t a y a w a y f r o m t h e o v a l w i n d o w a t

all t i m e s . S u c t i o n i n g p e r i l y m p h i n t h e o v a l w i n d o w

c a n c a u s e a " d e a d e a r . "

T h e i n c u d o s t a p e d i a l jo in t i s g e n t l y s e p a r a t e d w i t h

a jo in t kn i fe (F ig . 1 3 - 7 8 ) ; t h e knife i s sl id b e t w e e n

t h e i n c u s a n d t h e h e a d o f t h e s t a p e s t o e n s u r e t h a t

s e p a r a t i o n i s t o ta l . T h e s t a p e d i a l t e n d o n i s s e c t i o n e d

w i t h t h e j o i n t kn i fe o r a B e l l u c c i s c i s s o r s (F ig . 1 3 - 7 C ,

D ) . S o m e t i m e s i t i s p o s s i b l e to g e n t l y p e e l i t a l o n g

w i t h t h e m u c o p e r i o s t e u m a n d l e a v e i t a t t a c h e d t o

t h e l o n g p r o c e s s o f t h e i n c u s ( F i g . 1 3 - 7 E , F ) . T h i s

a l l o w s p e r h a p s s o m e p r o t e c t i o n f r o m s o u n d a n d

p e r m i t s b e t t e r v a s c u l a r i t y t o t h e l o n g p r o c e s s o f t h e

i n c u s . I n t h e u n u s u a l e v e n t o f a p r o m i n e n t p y r a m i d a l

e m i n e n c e , t h e t e n d o n i s s e c t i o n e d a n d t h e e m i n e n c e

c u r e t t e d . T h e h e a d a n d c r u r a o f t h e s t a p e s ( s t a p e d i a l

a r c h ) a r e m o b i l i z e d w i t h a n a n g l e d h o o k t o w a r d t h e

p r o m o n t o r y a n d not i n a n a n t e r o p o s t e r i o r d i r e c t i o n

( w h i c h c a n c a u s e p a r t o f t h e f o o t p l a t e t o d r o p i n t o

t h e o v a l w i n d o w ) . U s u a l l y t h e a r c h f r a c t u r e s a t t h e

j u n c t i o n s o f t h e c r u r a w i t h t h e f o o t p l a t e , a n d i s

r e m o v e d w i t h t h e a n g l e d h o o k o r a b a b y a l l i g a t o r

f o r c e p s ( F i g . 1 3 - 7 G ) . M e a s u r e m e n t s a r e n o w m a d e

(Fig . 1 3 - 7 H ) .

A t t h i s p o i . i t , t h e p a t i e n t i s i n s t r u c t e d n o t t o m o v e

o r ta lk . S i m i l a r r e c o m m e n d a t i o n s a p p l y t o t h o s e i n

t h e o p e r a t i n g r o o m . T h e f o o t p l a t e i s r e m o v e d w i t h a

H o u g h h o e o r a r i g h t - a n g l e d h o o k ( F i g . 1 3 - 8 4 ) . I t i s

255

'"

Surgery lor Stapes Fixation

o Malleus to oval window

1---4mm--j

B

A

0.005 starnless steel wire

Gelloam

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Surgery for Stapes Fixation254

FICURE 1:\-5 FlCURE 13-<>.

256 S u r g e r y fo r S t a p e s F i x a t i o n

FIGURE 13-7

S u r g e r y for S t a p e s F i x a t i o n 257

i m p o r t a n t t o p l a c e t h e i n s t r u m e n t j u s t b a r e l y b e n e a t h

t h e f r a g m e n t s t o b e r e m o v e d i n o r d e r t o a v o i d

d a m a g i n g t h e u n d e r l y i n g v e s t i b u l a r s t r u c t u r e s . B o n e

f r a g m e n t s a r e e i t h e r t o t a l l y o r p a r t i a l l y r e m o v e d

( u s u a l l y b y r e m o v i n g t h e p o s t e r i o r t w o t h i r d s o f t h e

f o o t p l a t e ) , d e p e n d i n g u p o n t h e p r o c e d u r e t o b e d o n e

( F i g . 1 3 - 8 A ) .

W i t h a n a l l i g a t o r f o r c e p s o r a h o r i z o n t a l o p e n i n g

f o r c e p s ( w h i c h a l l o w s b e t t e r v i s u a l i z a t i o n ) h o l d i n g

t h e b a r e e d g e o f t h e w i r e , t h e p r o s t h e s i s i s p l a c e d

( F i g . 1 3 - 8 B ) . I f i t c a n n o t b e p l a c e d e a s i l y i n p o s i t i o n ,

i t i s r e l e a s e d a n d m o b i l i z e d b i m a n u a l l y ( f o r e x a m p l e ,

w i t h t h e s u c t i o n t i p a n d a H o u g h h o e ) . I f t h e w i r e i s

b e n t d u r i n g p o s i t i o n i n g , i t i s b e t t e r t o u s e a n e w

p r o s t h e s i s t h a n t o fix it. T h e o v a l w i n d o w s h o u l d b e

lef t o p e n for t h e s h o r t e s t t i m e p o s s i b l e ; e x c e s s i v e

t i m e o f e x p o s u r e i s d i r e c t l y r e l a t e d t o e f f e c t s o n

h e a r i n g . O n c e t h e w i r e c o n n e c t i v e t i s s u e i s w e l l

c e n t e r e d , a d d i t i o n a l c o n n e c t i v e t i s s u e c a n b e u s e d t o

s e a l t h e w i n d o w . I f a p r o s t h e s i s w i t h o u t c o n n e c t i v e

t i s s u e i s u s e d , t h e o v a l w i n d o w g ra f t i s p l a c e d b e f o r e

t h e p r o s t h e s i s ( F i g . 1 3 - 8 C ) . S u c h a g r a f t i d e a l l y

s h o u l d fit p r e c i s e l y ; i t c a n n o t b e t o o s m a l l o r t o o

l a r g e . I f a p i s t o n i s u s e d , c o n n e c t i v e t i s s u e i s w r a p p e d

a r o u n d i t . S m a l l p i e c e s o f G e l f o a m c a n t h e n b e p l a c e d

o v e r t h e c o n n e c b v e t i s s u e a n d a r o u n d t h e p r o s t h e s i s .

P i s t o n w i d t h i n a s t a p e d e c t o m y i s f r o m 0 . 6 t o 0 . 8

m m , w h e r e a s i n a s t a p e d o t o m y ( d e s c r i b e d b e l o w ) , i t

i s 0 . 4 m m .

T h e p r o s t h e s i s i s c r i m p e d w i t h a M c G e e c r i m p e r

o r a n a l l i g a t o r f o r c e p s . T h e c r i m p e r h a s t h e a d v a n t a g e

o f n o t c l o s i n g c o m p l e t e l y ; t h u s t h e r e i s l e s s c h a n c e

o f f r a c t u r i n g t h e l o n g p r o c e s s o f t h e i n c u s ( F i g . 1 3 -

8 D ) . I t i s a l s o l i g h t a n d t h i n a n d d o e s n o t o b s t r u c t

v i s i o n . C r i m p i n g i s d o n e i n a n a n t e r o p o s t e r i o r d i r e c ­

t i o n a n d i n v o l v e s o n l y t h e r i n g a r o u n d t h e i n c u s ;

o t h e r w i s e , t h e p r o s t h e s i s w i l l b e b e n t a n d wi l l h a v e

t o b e c h a n g e d . T e f l o n w i r e p i s t o n s b e n d v e r y e a s i l y

i f n o t c r i m p e d p r o p e r l y . T h e r o u n d w i n d o w r e f l e x ,

t h e m o b i l i t y o f t h e o s s i c u l a r c h a i n , a n d t h e a d e q u a c y

o f t h e p r o s t h e s i s p o s i t i o n a r e c h e c k e d a t t h i s p o i n t ,

a f t e r w h i c h t h e f l ap I s r e p o s i t i o n e d . T h e p a t i e n t i s

t h e n a s k e d i f t h e r e i s a n y i m p r o v e m e n t i n h e a r i n g .

F i n a l l y , t h e e a r c a n a l i s p a c k e d ( d e s c r i b e d b e l o w ) .

Problems and Variations During Surgery

Bleeding. S m a l l v e s s e l s r e s p o n d v e r y w e l l t o t o p i c a l

a p p l i c a t i o n o f c o t t o n b a l l s o r G e l f o a m s a t u r a t e d w i t h

e p i n e p h r i n e . I n t h e f o o t p l a t e i t i s p r e f e r a b l e t o u s e

G e l f o a m i n o r d e r t o a v o i d c o t t o n s t r a n d s . L i d o c a i n e

( X y l o c a i n e ) w i t h e p i n e p h r i n e s h o u l d >iof b e u s e d i n

t h e o p e n v e s t i b u l e s i n c e i t c a n c a u s e m a r k e d v e s t i b ­

u l a r d i s t u r b a n c e s . T h e p r e s e n c e o f a n a b n o r m a l j u g ­

u l a r b u l b h a s b e e n d e s c r i b e d i n a n o t h e r c h a p t e r ; i f

i t s l o c a t i o n a l l o w s a s a f e e x p l o r a t i o n a n d s t a p e s

p r o c e d u r e , i t s h o u l d n o t be a c o n t r a i n d i c a t i o n . A

p e r s i s t e n t s t a p e d i a l a r t e r y ( r u n n i n g o v e r t h e f o o t ­

p l a t e ) i s a v e r y u n u s u a l f i n d i n g . T h i s a r t e r y i s fa i r ly

l a r g e a n d s h o j l d n o t b e c o n f u s e d w i t h s m a l l b u t

p r o m i n e n t m u c o p e r i o s t e a l v e s s e l s i n t h e f o o t p l a t e . I f

a s m a l l o p e n i n g o n t h e f o o t p l a t e c a n b e m a d e a n d a

s m a l l p i s t o n p l a c e d , t h e p r o c e d u r e c a n b e d o n e ;

o t h e r w i s e , t h e o p e r a t i o n s h o u l d n o t t a k e p l a c e .

O b l i t e r a t i o n o f t h e r o u n d w i n d o w a n d f i x a t i o n o f

t h e m a l l e u s h a v e b e e n d e s c r i b e d .

Accidental Dislocation of the Incus. T h e i n c u s s h o u l d

b e p a l p a t e d . I f t h e d i s l o c a t i o n i s p a r t i a l a n d t h e i n c u s

m o v e s w i t h t h e m a l l e u s , t h e p r o s t h e s i s i s p l a c e d a s

u s u a l . I f i t i s t o t a l l y l u x a t e d , a m a l l e u s - t o - o v a l w i n ­

d o w p r o s t h e s i s ( o r a n e q u i v a l e n t p r o s t h e s i s , a s d e ­

s c r i b e d i n C h a p t e r 1 2 ) i s s u b s t i t u t e d .

F r a c t u r e o f t h e l o n g p r o c e s s o f t h e i n c u s w h i l e

c r i m p i n g t h e p r o s t h e s i s i s r a r e ; i f i t h a p p e n s , t h e

p r o s t h e s i s c a n b e c r i m p e d o n t h e r e m a i n i n g s t r u t

( F i g . 1 3 - 9 4 ) . I f t h i s i s i m p o s s i b l e , a m a l l e u s - t o - o v a l

w i n d o w p r o s t h e s i s ( o r i t s e q u i v a l e n t ) c a n b e u s e d

i n s t e a d .

Pain. A n o c c a s i o n a l p a t i e n t m i g h t c o m p l a i n o f p a i n

w h e n t h e m i d d l e e a r m u c o s a i s t o u c h e d . T o p i c a l

a p p l i c a t i o n o f ' : . % l i d o c a i n e i n c o t t o n o r G e l f o a m

p l e d g e t s s u f f i c e s .

Prominent Promontory. T h i s c a n be d r i l l e d c a r e f u l l y

i n o r d e r t o pro* i d e a d e q u a t e v i s u a l i z a t i o n ( F i g . 1 3 -

9 C ) . D e p e n d i n g u p o n t h e v i s u a l i z a t i o n o b t a i n e d , a

s m a l l p i s t o n o r A w i r e c o n n e c t i v e t i s s u e p r o s t h e s i s i s

p l a c e d . A n a b n o r m a l ( o p e n o r r e d u n d a n t ) s e v e n t h

n e r v e i n i t s e l f i s n o t a c o n t r a i n d i c a t i o n . I t m a y b e

p o s s i b l e t o m o b i l i z e i t g e n t l y w i t h a b l u n t h o o k ,

a l l o w i n g a n o p e n i n g t o b e m a d e i n t h e f o o t p l a t e for

p l a c e m e n t o f a p r o s t h e s i s . S o m e t i m e s , d e p e n d i n g

u p o n t h e a n a t o m i c c o n d i t i o n s , a w i r e c o n n e c t i v e

t i s s u e p r o s t h e s i s c a n b e b e n t t o fit. O n o c c a s i o n , a n

o f f s e t R o b i n s o n p r o s t h e s i s f i ts p r e c i s e l y . F l e x i b i l i t y

a n d u s e o f a p r o s t h e s i s t o fit t h e n e e d a r e p a r a m o u n t ;

t h e c o u r s e o f a c t i o n s h o u l d r e f l e c t t h e a n a t o m i c a n d

f u n c t i o n a l n e e d s o f t h e p a t i e n t a n d t h e r a t i o n a l a n d

s a f e a p p r o a c h o f t h e s u r g e o n .

Narrow Oval Window. A n a r r o w w i n d o w c a n be

s e c o n d a r y t o a p r o m i n e n t o v e r l y i n g p r o m o n t o r y ; i t

c a n a l s o r e p r e s e n t a c o n g e n i t a l d e f e c t , w h i c h n o t

u n c o m m o n l y l e a d s t o a p e r i l y m p h " g u s h e r . " I t i s

a l s o v e r y i m p o r t a n t t o a s s e s s t h e fac ia l n e r v e a n d i ts

r e l a t i o n s h i p t o t h e f o o t p l a t e ( F i g . 1 3 - 9 D ) . I f t h e

w i n d o w i t s e l f i s q u i t e n a r r o w a n d a c o n g e n i t a l d e f e c t

i s s u s p e c t e d , a s m a l l o p e n i n g c a n b e m a d e w i t h a

258 Surgery for Stapes FixationSurgery for Stapes Fixation 259

c

A

A

HGURE 1:1-8FIGURE 13-9.

S u r g e r v f o r S t a p e s F i x a t i o n 261

s m a l l , s h a r p n e e d l e ; i f a g u s h e r i s f o u n d , i t i s c o v e r e d

wi th c o n n e c t i v e t i s s u e a n d G e l f o a m . T h e h e a d o f t h e

p a t i e n t i s r a i s e d a n d t h e p r o c e d u r e i s t e r m i n a t e d . I f

t h e r e i s n o g u s h e r , t h e s m a l l o p e n i n g c a n b e e n l a r g e d

to p l a c e a 0 . 4 - m m p i s t o n o r a t h i n p r o s t h e s i s .

Cerebrospinal Fluid Leak. A " g u s h e r " is u n c o m m o n ,

a n d i s g e n e r a l l y ( b u t n o t e x c l u s i v e l y ) s e e n i n c a s e s

o f a c o n g e n i t a l l y f i xed s t a p e s ( a n d a p a t e n t c o c h l e a r

a q u e d u c t ) . T h e p a t i e n t ' s h e a d i s e l e v a t e d a n d a l a r g e

c o n n e c t i v e t i s s u e w i r e p r o s t h e s i s u s e d for a s e a l ,

wi th a d d i t i o n a l c o n n e c t i v e t i s s u e .

Dry Vestibule. I f t h e p e r i l y m p h i s a c c i d e n t a l l y s u c ­

t i o n e d o u t o f t h e o v a l w i n d o w ( t h e s u c t i o n t ip s h o u l d

nettcr b e p u t i n t o t h e o v a l w i n d o w [ F i g . 1 3 - 1 0 E , F ] ) ,

the w i n d o w wi l l r e f i l l . I f i t d o e s n o t , a f e w d r o p s o f

sa l ine a r e u s e d t o fill it. B l o o d m i g h t s t i m u l a t e a n

i n f l a m m a t o r y r e a c t i o n i n t h e v e s t i b u l e .

Floating Footplate. T h i s r e f e r s to a f o o t p l a t e t h a t

b e c o m e s m o b i l e b e f o r e a n o p e n i n g i s m a d e i n i t a n d

after r e m o v a l o f t h e a r c h ( t h e s u p e r s t r u c t u r e c o n s i s t ­

ing o f t h e h e a d a n d c r u r a ) . T h i s i s a d i f f i cu l t c h a l ­

l e n g e . O n e w a y t o a v o i d i t i s t o f r a c t u r e t h e f o o t p l a t e

be fo r e r e m o v i n g t h e a r c h . A f l o a t i n g f o o t p l a t e t e n d s

t o o c c u r i n a s t a p e s t h a t h a s b e e n p r e v i o u s l y m o b i ­

l ized o r i n o n e w i t h p o o r f i x a t i o n .

S o m e t i m e s t h e f o o t p l a t e c a n b e c a r e f u l l y r e m o v e d

wi th a n a n g l e d h o o k . I f t h i s i s i m p o s s i b l e , a n o p e n i n g

can b e m a d e w i t h a d i a m o n d b u r o r s m a l l b u r i n t h e

a n t e r o i n f e r i o r m a r g i n , a n d t h e f o o t p l a t e r e m o v e d

wi th a h o o k ( F i g . 1 3 - 1 0 4 , 8 ) . I f t h i s t o o i s i m p o s s i b l e

a n d t h e f o o t p l a t e i s n o t d e p r e s s e d , f a s c i a c a n b e

p l a c e d o v e r i t a n d a s h o r t e r p i s t o n p l a c e d . I f

r e f ixa t ion o c c u r s ( w h i c h i s l i k e l y ) , t h e f o o t p l a t e

can b e r e v i s e d w i t h b e t t e r c h a n c e s o f s u c c e s s ( F i g

1 3 - 1 0 C ) .

Depressed Fragments. D e p r e s s e d f r a g m e n t s c a n be

r e m o v e d c a r e f u l l y w i t h a h o o k , b u t " f i s h i n g " i n t h e

v e s t i b u l e s h o u l d b e a v o i d e d ; i t i s b e t t e r t o l e a v e t h e

f r a g m e n t s i n t h e v e s t i b u l e a n d u s e a m p l e a m o u n t s

o f s t e r o i d s , t o p i c a l l y a n d p a r e n t e r a l l y . S o m e a u t h o r s

r e c o m m e n d p l a c i n g a f e w d r o p s o f b l o o d i n t h e

v e s t i b u l e a n d a l l o w i n g t h e m t o c l o t ; w h e n t h e c l o t i s

r e m o v e d t h e f r a g m e n t s m a y c o m e o u t w i t h i t ( F i g .

1 3 - 1 0 D ) .

Obliterative Otosclerosis

I f a n o b l i t e r a t i v e f o c u s i s f o u n d — f o r e x a m p l e , i f

the o v a l w i n d o w h a s n o d i s c e r n i b l e f o o t p l a t e o w i n g

t o o t o s c l e r o t i c c h a n g e ( F i g . 1 3 - 1 1 4 ) — t h e p r o c e d u r e

i s d i f f e r e n t . I f t h e p a t i e n t i s a c h i l d w i t h an a c t i v e

f o c u s , i t i s b e t t e r t o d e l a y t h i s p r o c e d u r e . ( T h e

q u e s t i o n o f o p e r a t i n g o n c h i l d r e n w i t h o t o s c l e r o s i s

i s n o t a n e a s y o n e ; i n g e n e r a l , i t s e e m s b e t t e r t o

d e l a y s u c h p r o c e d u r e s b u t s o m e s u r g e o n s d o p e r f o r m

t h e m , r e p o r t e d l y w i t h g o o d r e s u l t s . )

A t h i c k f o o t p l a t e m u s t b e t h i n n e d w i t h a 0 . 6 - t o

1 - m m c u t t i n g o r d i a m o n d b u r w i t h s l o w r o t a t i o n

( F i g . 1 3 - 1 1 8 ) . T h i s i s d o n e a n t e r o p o s t e r i o r l y , s a u c e r -

i z i n g e v e n l y a n d a p p l y i n g j u s t e n o u g h p r e s s u r e o v e r

t h e f o o t p l a t e t o b e e f f e c t i v e . B o n e d u s t i s m e t i c u ­

l o u s l y r e m o v e d . I f t h e f o o t p l a t e i s t h i n n e d e v e n l y ( t o

a t h i n b l u i s h p l a t e ) , a s m a l l ( 0 . 5 - m m ) o p e n i n g i s

m a d e a n d a p i s t o n s u r r o u n d e d b y c o n n e c t i v e t i s s u e

i s p l a c e d ( F i g . 1 3 - 1 1 C - E ) . L e s s c o m m o n l y , t h e foo t ­

p l a t e i s f r a c t u r e d a n d r e m o v e d , a n d a g r a f t i s p l a c e d .

Stapedotomy

T h i s p r o c e d u r e h a s g a i n e d m a n y a d v o c a t e s i n

r e c e n t y e a r s b e c a u s e i t h a s b e e n s u g g e s t e d t h a t i t

i n v o l v e s l e s s r i s k o f i n n e r e a r d a m a g e , l e s s c h a n c e o f

a d h e s i o n s b e t w e e n t h e g r a f t a n d v e s t i b u l a r c o n t e n t s ,

a n d l e s s m o b i l i t y o f t h e o v a l w i n d o w a s a w h o l e . A s

w i t h all s u r g i c a l i n n o v a t i o n s , t i m e a n d e x p e r i e n c e

wi l l t e l l . T h e p r o c e d u r e a l s o c a n b e d o n e w i t h a l a s e r

( s e e C h a p t e r 1 4 ) . T h e o p e r a t i o n i s s i m i l a r t o a c l a s s i c

s t a p e d e c t o m y , u p t o t h e p o i n t o f o p e n i n g t h e foo t ­

p l a t e . T h e n t h e f o o t p l a t e i s p e r f o r a t e d w i t h a s h a r p

n e e d l e ( o r s p e c i a l m i c r o d r i l l ) i n t h r e e d i f f e r e n t s p o t s .

E n l a r g e m e n t o f t h e s e o p e n i n g s i s d o n e v e r y c a r e f u l l y

w i t h a n g l e d h o o k s , t r y i n g t o l e a v e a s i n g l e c e n t r a l

o p e n i n g t h a t i s s l i g h t l y l a r g e r t h a n 0 . 4 m m . T h e s i z e

c a n b e m e a s u r e d w i t h a 0 . 4 - m m m e a s u r i n g r o d . T h i s

s t e p c a n b e d o n e w i t h o u t r e m o v i n g t h e s t a p e s a r c h ,

a v o i d i n g m o b i l i z a t i o n o f t h e s t a p e s . O n c e t h i s i s

d o n e , t h e i n c u d o s t a p e d i a l j o i n t i s s e p a r a t e d a n d t h e

c r u r a a r e sectioned w i t h c r u r o t o m y s c i s s o r s ; t h e p r o s ­

t h e s i s i s t h e n p l a c e d o v e r t h e i n c u s a n d i n t o t h e

f o o t p l a t e o p e n i n g a n d s u r r o u n d e d w i t h c o n n e c t i v e

t i s s u e .

Stapes Interposition

I n t h e p r e s e n c e o f a w i d e n i c h e , a n a n t e r i o r f i x a ­

t i o n , a n d a h e a l t h y p o s t e r i o r c r u s , a n i n t e r p o s i t i o n

p r o c e d u r e i s a r a t i o n a l a l t e r n a t i v e . I t r e p r e s e n t s a

s a f e a n d l o g i c a l a p p r o a c h b u t i s d i f f i cu l t t o p e r f o r m

p r o p e r l y , r e q u i r i n g a b i l i t y a n d e x p e r i e n c e . T h e p r o ­

c e d u r e i n v o l v e s r e m o v i n g a p o r t i o n o f t h e f o o t p l a t e

( f i x e d ) a n d m o b i l i z i n g t h e p o s t e r i o r c r u s ( a s a " p r o s ­

t h e s i s " ) o v e r a n u n d e r l y i n g g r a f t , t h u s r e - e s t a b l i s h i n g

t h e c o n t i n u i t y a n d m o b i l i t y o f t h e o s s i c u l a r c h a i n .

!

S u r g e r y fo r S t a p e s F i x a t i o n 263

I n i t i a l l y t h e a n t e r i o r c r u s i s s e c t i o n e d w i t h a n g l e d

c r u r o t o m y s c i s s o r s ( F i g . 1 3 - 1 2 / 1 ) . P o r t m a n n ( a n a d ­

v o c a t e o f t h i s p r o c e d u r e ) r e c o m m e n d s s e c t i o n i n g i n

t h e m a i n a x i s o f t h e s t a p e s , i n t r o d u c i n g t h e s c i s s o r s

b e t w e e n t h e m a l l e u s a n d t h e i n c u s , s i n c e t h e s i m p l e r

a p p r o a c h t h r o u g h t h e p r o m o n t o r y c a r r i e s t h e r i s k o f

f r a c t u r i n g t h e s t a p e s a t a n o t h e r s i t e . T h i s i s f o l l o w e d

b y s e c t i o n i n g o f t h e s t a p e d i a l t e n d o n . T h e p o s t e r i o r

c r u s i s t h e n c a r e f u l l y f r a c t u r e d w i t h a m i c r o h o o k a t

i t s j u n c t i o n w i t h t h e f o o t p l a t e . W h e n t h e p o s t e r i o r

c r u s i s f r e e ( f r o m m u c o s a l a d h e s i o n s a s w e l l ) , i t i s

m o b i l i z e d a n t e r i o r l y w h i l e t h e i n c u s i s l i f t ed w i t h a

H o u g h h o e ( t h u s a v o i d i n g f r a c t u r e s i n t h e p o s t e r i o r

c r u s ) ( F i g . 1 3 - 1 2 B ) . T h e f o o t p l a t e i s f r a c t u r e d a n d t h e

p o s t e r i o r t w o t h i r d s a r e r e m o v e d ( F i g . 1 3 - 1 2 C a n d

F i g . 1 3 - 1 3 A ) . A g ra f t i s p l a c e d a n d t h e p o s t e r i o r c r u s

i s r e p o s i t i o n e d o v e r t h e g ra f t ( w h i l e t h e i n c u s i s

l i f t e d ) , r e - e s t a b l i s h i n g o s s i c u l a r c o n t i n u i t y a n d m o ­

b i l i t y ( F i g . 1 3 - 1 3 B - D ) .

S o m e s u r g e o n s p e r f o r m t h i s p r o c e d u r e b y r e m o v ­

i n g p a r t o f t h e a n t e r i o r c r u s a n d t h e a n t e r i o r h a l f o f

t h e f o o t p l a t e ( a n a n t e r i o r c r u r o t o m y ) . T h e r e m a i n i n g

m o b i l e p o s t e r i o r c r u s a n d u n d e r l y i n g m o b i l e f o o t ­

p l a t e a r e m o b i l i z e d t o w a r d t h e c e n t e r o f t h e o v a l

w i n d o w ( o v e r t h e g r a f t ) . T h e s t a p e d i a l t e n d o n m i g h t

o r m i g h t n o t b e s e c t i o n e d , a c c o r d i n g t o n e e d . A

p o s t e r i o r c r u r o t o m y a l s o c a n b e d o n e i n r e v e r s e

f a s h i o n , b u t u s u a l l y t h e p o i n t o f f o o t p l a t e f i x a t i o n i s

a n t e r i o r .

Malleus-to-Oval Window Prosthesis

T h e a i m o f t h i s p r o c e d u r e i s t o p l a c e a w i r e

p r o s t h e s i s f r o m t h e h a n d l e o f t h e m a l l e u s t o t h e o v a l

w i n d o w . I t i s i m p o r t a n t t o p l a c e t h e w i r e u n d e r a

s u b p e r i o s t e a l p o c k e t i n t h e h a n d l e o f t h e m a l l e u s , a s

c l o s e t o t h e s h o r t p r o c e s s a s p o s s i b l e .

S u c h p r o s t h e s e s a r e c o m m e r c i a l l y a v a i l a b l e , b u t a

w i r e c o n n e c t i v e t i s s u e c a n b e m a d e . S t a p e s p r o s t h e s i s

w i r e a n d a b e n d i n g d i e a r e u s e d t o m a n u f a c t u r e a

p r o s t h e s i s ; o n l y t h e l a r g e p o s t o f t h e d i e i s u s e d t o

s h a p e t h e " c r o o k " o r " h a n d l e " ( s e e F i g . 1 3 - 5 ) .

W i t h a j o i n t k n i f e , a n i n c i s i o n i s m a d e t h r o u g h

t h e m u c o p e r i o s t e u m o n t h e u n d e r s u r f a c e o f t h e h a n ­

d l e o f t h e m a l l e u s , c r e a t i n g a s u b p e r i o s t e a l p o c k e t

( F i g . 1 3 - 1 4 / 1 ) . O n o c c a s i o n i t i s n e c e s s a r y ( b e c a u s e

o f c o n t a c t w i t h t h e o v e r l y i n g t y m p a n i c m e m b r a n e )

t o p l a c e t h e p r o s t h e s i s a t t h e n e c k o f t h e m a l l e u s .

T h e s t a p e s a r c h i s r e m o v e d f i rs t , a n d t h e p r o s t h e s i s

i s p l a c e d t o e n s u r e c o r r e c t l e n g t h . I n i t i a l l y t h e p r o s ­

t h e s i s i s h e l d i n a m a n n e r s i m i l a r t o a s t a p e s p r o s ­

t h e s i s , b u t i t i s p l a c e d a t a r i g h t a n g l e t o t h e m a l l e u s

h a n d l e ( F i g . 1 3 - 1 4 6 ) . O n c e i t i s o v e r t h e m a l l e u s

h a n d l e ( u n d e r t h e p e r i o s t e a l p o c k e t ) , i t i s t u r n e d

d o w n s o t h a t i t i s p e r p e n d i c u l a r t o t h e h a n d l e ; t h i s

m a n e u v e r m a k e s p o s i t i o n i n g e a s i e r . I f t h e l e n g t h i s

s a t i s f a c t o r y , t h e p r o s t h e s i s i s d i s p l a c e d a n t e r i o r l y ,

t h e f o o t p l a t e i s r e m o v e d , a n d a c o n n e c t i v e t i s s u e

g ra f t i s p l a c e d o v e r t h e o v a l w i n d o w . T h e p r o s t h e s i s

i s p o s i t i o n e d a n d t h e n t i g h t e n e d b i m a n u a l l y ( w i t h

a n a n g l e d h o o k a n d s u c t i o n t ip o r b l u n t i n s t r u m e n t )

a l o n g t h e u n d e r s u r f a c e o f t h e m a l l e u s ( F i g . 1 3 - 1 4 C ) .

I t s h o u l d b e r e m e m b e r e d t h a t , r e g a r d l e s s o f h o w

w e l l t h e p r o s t h e s i s m i g h t f i t , i t i s a n a t o m i c a l l y a n d

f u n c t i o n a l l y l e s s e f f i c i e n t t h a n a s t a p e d e c t o m y p r o s ­

t h e s i s ; a t t h e s a m e t i m e , t h e o v a l w i n d o w i s s u b j e c t e d

t o m o r e t r a u m a ( t h e m o b i l i t y o f t h e m a l l e u s i s g r e a t e r

t h a n t h a t o f t h e i n c u s a n d h a s l e s s d a m p e n i n g e f f e c t ) .

Closure and Packing

T h e f l ap i s c a r e f u l l y r e p o s i t i o n e d . I f a s m a l l t e a r i s

p r e s e n t , t h e e d g e s a r e c a r e f u l l y a p p r o x i m a t e d . I f

n e c e s s a r y , s m a l l p i e c e s o f G e l f o a m o r c o n n e c t i v e

t i s s u e c a n b e u s e d , a n d t h e f l ap left s o m e w h a t l o o s e .

F o r l a r g e r p e r f o r a t i o n s , a g r a f t i s p l a c e d a n d a m p l e

a m o u n t s o f a n t i b i o t i c s a n d a n t i - i n f l a m m a t o r y m e d i ­

c a t i o n s a r e u s e d . P a c k i n g t e c h n i q u e s h a v e b e e n d e ­

s c r i b e d . T h e p a t i e n t m u s t l i e w i t h t h e o p e r a t e d e a r

u p a n d i s c l o s e l y f o l l o w e d p o s t o p e r a t i v e l y ; t h e n e e d

t o a v o i d s t r a i n i n g , l i f t i n g , o r u n d u e e f f o r t c a n n o t b e

e m p h a s i z e d e n o u g h . C o m p l i c a t i o n s c o n t i n u e t o b e

v e r y p o s s i b l e u n t i l c o m p l e t e h e a l i n g h a s o c c u r r e d (a t

f o u r t o s ix w e e k s ) a n d m a y st i l l o c c u r t h e r e a f t e r .

S o m e f a i l u r e s c a n b e t r a c e d t o o v e r c o n f i d e n c e i n t h e

o p e r a t i v e p r o c e d u r e . I t h a s b e e n a r g u e d t h a t p r o p h y ­

l a c t i c a n t i b i o t i c s a r e u n n e c e s s a r y ; h o w e v e r , t h e a u ­

t h o r s s t r o n g i y r e c o m m e n d t h e u s e o f i n t r a o p e r a t i v e

a n d p o s t o p e r a t i v e a n t i b i o t i c s . J Complications

A s i n a n y s u r g i c a l p r o c e d u r e , a w a r e n e s s a n d p r e ­

v e n t i o n o f p o s s i b l e c o m p l i c a t i o n s a r e t h e k e y s . A d ­

e q u a t e p r e o p e r a t i v e e v a l u a t i o n , a w e l l - d e f i n e d d i a g ­

n o s i s , a n d r a t i o n a l s u r g i c a l p l a n s a r e o f p a r a m o u n t

i m p o r t a n c e . T h e p a t i e n t o n t h e o p e r a t i n g t a b l e i s

a s s u m e d t o h a v e h a d a t h o r o u g h o v e r a l l c h e c k ( in ­

c l u d i n g c a r d i o v a s c u l a r s t a t u s , a l l e r g i e s , e n d o c r i n o -

l o g i c p r o b l e m s , a n d s o o n ) .

!

264 Surgery for Stapes Fixation

B

FIGURE 13-12.

c

Surgery for Stapes Fixation 265

FIGURE 13-13.

D y s g e u s i a f o l l o w i n g i n j u r y t o t h e c h o r d a t y m p a n i

i s c h a r a c t e r i z e d b y t i n g l i n g o r a m e t a l l i c t a s t e o n t h e

t o n g u e o n t h e o p e r a t e d s i d e , o r b o t h . T h i s a l w a y s

i m p r o v e s , b u t t h e r e a s o n for t h e i m p r o v e m e n t i s

u n c l e a r .

I n f e c t i o n i s r a r e , e s p e c i a l l y i f a d e q u a t e p r o p h y l a x i s

( i n c l u d i n g m e t i c u l o u s c l e a n s i n g o f t h e e a r c a n a l ) h a s

b e e n u n d e r t a k e n . I f i t o c c u r s , t h e p a c k i n g s h o u l d b e

r e m o v e d , c u l t u r e s o b t a i n e d ( i f p o s s i b l e ) , a n d a n t i ­

b i o t i c s g i v e n ( o r c h a n g e d ) t o p i c a l l y a n d p a r e n t e r a l l y .

I n f e c t i o n m a y l e a d t o l a b y r i n t h i t i s a n d s h o u l d b e

t r e a t e d a g g r e s s i v e l y .

F a c i a l p a l s y m a y f o l l o w i n j e c t i o n o f l oca l a n e s ­

t h e t i c s , b u t s h o u l d b e o n l y t e m p o r a r y . P a l s y i m m e ­

d i a t e l y f o l l o w i n g s t a p e d e c t o m y p r o b a b l y s i g n a l s

d a m a g e t o a n e x p o s e d n e r v e i n t h e o v a l w i n d o w

d u r i n g t h e p r o c e d u r e . S u r g i c a l r e - e x p l o r a t i o n i s in­

d i c a t e d . I t s h o u l d b e k e p t i n m i n d t h a t d a m a g e

p r o b a b l y i s r e s t r i c t e d t o loca l e d e m a o r p u n c t u r i n g

o f t h e n e r v e ; s e c t i o n i n g o f t h e n e r v e i s e x t r e m e l y

rare* D e l a y e d p a r a l y s i s m u s t b e e v a l u a t e d , a n d i s

t r e a t e d i n t h e s a m e m a n n e r a s B e l l ' s p a l s y .

V e r t i g o i s f a i r ly c o m m o n d u r i n g t h e f irst f e w

p o s t o p e r a t i v e d a y s ; h o w e v e r , s y m p t o m s s h o u l d b e

m i l d , s h o r t l i v e d , a n d r e s p o n s i v e t o r e s t a n d v e s t i b ­

u l a r s e d a t i v e s . V e r t i g i n o u s s y m p t o m s s h o u l d n o t b e

t a k e n l i g h t l y ; t h e y c o u l d b e a w a r n i n g s i g n , w h i c h

lef t u n a t t e n d e d m i g h t l e a d t o i r r e v e r s i b l e s e n s o r y

d e a f n e s s . P e r s i s t e n c e o f v e r t i g o o r s e v e r e v e r t i g o

m i g h t b e i n d i c a t i v e o f a p e r i l y m p h f i s t u l a , a t h i n o r

l e a k y g r a f t , p e r i p r o s t h e s i s l e a k a r o u n d a T e f l o n p i s ­

t o n ( a s s o c i a t e d w i t h f l u c t u a t i n g h e a r i n g l o s s ) , a p r o s ­

t h e s i s t h a t i s t o o l o n g , l a b y r i n t h i t i s , o r r e p a r a t i v e

g r a n u l o m a . O p e r a t i v e c a u s e s i n c l u d e t r a u m a d u r i n g

t h e o p e r a t i o n o r l o o s e b o n e f r a g m e n t s i n t h e v e s t i ­

b u l e . E a r l y t r a u m a o r b a r o t r a u m a m n v d i s p l a c e a

p r o s t h e s i s , l e a d i n g to a f i s t u l a .

I f t h e s e s y m p t o m s p e r s i s t i n s p i t e o f t h e r a p e u t i c

m e a s u r e s a n d c l i n i c a l j u d g m e n t s u g g e s t s a c o m p l i ­

c a t i o n , o r i f t h e r e i s a s e n s o r y h e a r i n g i n v o l v e m e n t ,

e x p l o r a t i o n i s i n d i c a t e d . W h e n r e v i s i n g a s t a p e d e c ­

t o m y ( o r a n y e a r p r o c e d u r e ) , s p e c i a l c a r e m u s t b e

t a k e n i n l i f t ing a t h i n s k i n f l a p . O v e r l o o k i n g t h i s

i m p o r t a n t p o i n t m i g h t l e a d t o s e r i o u s a n d u n n e c e s ­

s a r y t e a r s i n t h e f l ap o r t y m p a n i c m e m b r a n e . I n

g e n e r a l , n o t m u c h g ra f t i s r e m o v e d w h e n r e v i s i n g ,

a n d c o n n e c t i v e t i s s u e i s p l a c e d a r o u n d t h e o v a l

w i n d o w g r a f t . T h e r o u n d w i n d o w i s e v a l u a t e d for

t e a r s ; i f i t i s q u e s t i o n a b l e , a s m a l l p i e c e o f G e l f o a m

c a n b e u s e d t o o b l i t e r a t e t h e n i c h e . I f t h e p r o s t h e s i s

i s f o u n d t o b e t o o l o n g , t h e w i r e c a n b e g e n t l y b e n t

t •

I

b i m a n u a l l y a n d t h e p r o s t h e s i s s h o r t e n e d . I f t h i s i s

i m p o s s i b l e "or i n a d e q u a t e , t h e p r o s t h e s i s s h o u l d b e

r e p l a c e d . r t e p l a c e m e n t c a r r i e s t h e r i sk o f p u l l i n g

v e s t i b u l a r a d h e s i o n s . V e r t i g o l e a d i n g t o s e n s o r y

d e a f n e s s i s r a r e a f t e r o n e m o n t h , b u t c a n o c c u r u p

t o t h r e e t o » ix y e a r s l a t e r . O n o c c a s i o n , v e r t i g o m i g h t

p e r s i s t for y e a r s , e v e n w i t h g o o d h e a r i n g ; i t m a y

e v e n t u a l l y r e q u i r e s u r g i c a l c o r r e c t i o n .

P a t i e n t s u s u a l l y h a v e a m i l d s e n s a t i o n o f e c h o i n g

a l o n g w i t h t i n n i t u s o f n o s i g n i f i c a n c e , b u t t i n n i t u s

a n d a f e e l i n g o f r e s o n a n c e m a y i n d i c a t e f i s t u l a e o r

l a b y r i n t h i t i s , e s p e c i a l l y i f a c c o m p a n i e d b y v e r t i g o .

R e p a r a t i v e g r a n u l o m a i s o n e o f t h e f e w e m e r g e n ­

c i e s f o l l o w i n g s t a p e d e c t o m y . I t o c c u r s o n e t o t w o

w e e k s a f t e r s u r g e r y a n d i s c h a r a c t e r i z e d b y d i m i n ­

i s h e d h e a r i n g f o l l o w i n g a n i n i t i a l g a i n . A d d i t i o n a l

s y m p t o m s i n c l u d e a u r a l f u l l n e s s , l o s s o f d i s c r i m i n a ­

t ion , a n d d i s e q u i l i b r i u m . T h e t y m p a n i c m e m b r a n e

m a y b e d u l l , r e d , a n d t h i c k e n e d , w i t h a h y p e r v a s -

c u l a r f l a p a n d i n f l a m m a t i o n i n t h e p o s t e r o s u p e r i o r

q u a d r a n t . R e m o v a l o f t h e g r a n u l o m a i s d o n e i n a

p i e c e m e a l f a s h i o n , a n d f a s c i a i s p l a c e d o v e r t h e g r a f t .

T h e p r o s t h e s i s c a n b e r e p l a c e d b y a n e w c o n n e c t i v e

t i s s u e w i r e p r o s t h e s i s . G r a n u l o m a s h a v e n o t b e e n

s h o w n t o r e c u r .

C o n d u c t i v e h e a r i n g l o s s e s o c c u r r i n g a f t e r i n i t i a l

g a i n s a r e i n d i c a t i o n s fo r r e v i s i o n . A p r u d e n t w a i t i n g

p e r i o d i s s u g g e s t e d . A p e r f o r a t e d t y m p a n i c m e m ­

b r a n e wi l l r e q u i r e a m y r i n g o p l a s t y . A d e l a y e d c o n ­

d u c t i v e h e a r i n g l o s s w i t h a n i n t a c t t y m p a n i c m e m ­

b r a n e s u g g i s t s p r o b l e m s w i t h t h e p r o s t h e s i s . I f t h e r e

a r e a d h e s i o n s a r o u n d t h e p r o s t h e s i s , t h e y s h o u l d b e

s h a r p l y e x c i s e d a n d G e l f i l m o r S i l a s t i c p l a c e d . I f

n e c e s s a r y , t h e p r o s t h e s i s i s r e p l a c e d . P r o s t h e s e s t h a t

a r e d i s p l a c e d c a n b e e i t h e r r e p o s i t i o n e d o r r e p l a c e d ;

i f t h e l a t t e r , t h e y a r e g e n t l y l o o s e n e d f r o m t h e l o n g

p r o c e s s o f t h e i n c u s w i t h a n g l e d h o o k s b i m a n u a l l y .

I f t h i s i s i m p o s s i b l e , t h e y c a n b e s e c t i o n e d w i t h s m a l l

s c i s s o r s a n d r e p l a c e d . I f n e c r o s i s o f t h e l o n g p r o c e s s

o f t h e i n c u s i s p r e s e n t , t h e p r o s t h e s i s i s p l a c e d i n

t h e r e m n a n t . I f t h i s i s i m p o s s i b l e , a m a l l e u s - t o - o v a l

w i n d o w p r o s t h e s i s ( o r p l a c e m e n t o f a b o n e gra f t o r

T O R P ) i s i n d i c a t e d .

A p i s t o n i s u s e d i f t h e r e i s r e c u r r e n t b o n e d e p o ­

s i t i o n w i t h c l o s u r e o f t h e o v a l w i n d o w . I f t h e f o c u s

i s a c t i v e a n d r i s k i s i n v o l v e d , t h i n g s s h o u l d b e left

a s t h e y a r e for t h e t i m e b e i n g . I t s h o u l d b e k e p t i n

m i n d t h a t ' .he r e s u l t s o f r e v i s i o n s t a p e d e c t o m y a r e

n o t s o g o o d a s i n p r i m a r y p r o c e d u r e s ; a t t h e s a m e

t i m e , v e s t i b u l a r i n v o l v e m e n t w i t h s e c o n d a r y s e n s o r y

h e a r i n g l o s s i s m o r e l i k e l y .

S u r g e r y fo r S t a p e s F i x a t i o n 267

268 S u r g e r y for S t a p e s F i x a t i o n

Pertinent Histopathology

F I G U R E 1 3 - 1 5

T h i s h o r i z o n t a l s e c t i o n s h o w s a l a r g e o t o s c l e r o t i c

f o c u s f i x ing t h e s t a p e s a n t e r i o r l y a n d p o s t e r i o r l y . T h e

s t a p e s f o o t p l a t e i s t h i c k e n e d . N o t e t h a t t h e b r a n c h e s

o f ( a c o b s o n ' s n e r v e o n t h e p r o m o n t o r y (parallel it-

rows) a r e a l m o s t e n t i r e l y s u r r o u n d e d b y o t o s c l e r c ' . i c

b o n e .

S u r g e r y for S t a p e s F i x a t i o n 269

F I G U R E 1 3 - 1 6

T h i s s e c t i o n a t t h e l e v e l o f t h e o v a l w i n d o w a r e a f o o t p l a t e h a s b e e n e x c i s e d ; t h e s i t e i s e v i d e n t . T h e

i s f r o m t h e t e m p o r a l b o n e o f a n i n d i v i d u a l w h o h a d v e s t i b u l e i s i n t a c t . N o t e t h e c l o s e p r o x i m i t y o f t h e

a s u c c e s s f u l s t a p e d e c t o m y . P a r t o f t h e o t o s c l e r o t i c v e s t i b u l a r c o n t e n t s .

1

270 S u r g e r y for S t a p e s F i x a t i o n

Cochlea

F I G U R E 1 3 - 1 7

T h i s s e c t i o n i s f r o m t h e t e m p o r a l b o n e o f a n

i n d i v i d u a l w h o u n d e r w e n t a s t a p e d e c t o m y w i t h a

p i s t o n p r o s t h e s i s . T h e s i t e o f p l a c e m e n t i s e v i d e n t ; p l a c e d s u b s e q u e n t l y

i t c a n b e s e e n t h a t t h e p i s t o n w a s t o o d e e p a n d

i m p i n g e d o n t h e v e s t i b u l a r s t r u c t u r e s . T h e s u r g i c i j

r e s u l t w a s n o t i d e a l , a n d t h e p a t i e n t h a d t w o p i s t o n ;

S u r g e r y fo r S t a p e s F i x a t i o n 2 7 1

F I G U R E 1 3 - 1 8

T h i s h o r i z o n t a l s e c t i o n s h o w s a s t a p e s f i xed b y c o n d i t i o n s , t h e m i d d l e e a r p r o c e s s w o u l d i m m e d i -

o t o s c l e r o s i s a n d a m i d d l e e a r c a v i t y w i t h c h a n g e s a t e l y p e n e t r a t e t h e v e s t i b u l e , w i t h d i s a s t r o u s p o t e n -

c a u s e d b y o t i t i s m e d i a . T h e s e c t i o n s h o w s v e r y t ia l c o m p l i c a t i o n s . ( S o m e i n f l a m m a t i o n o f t h e v e s t i -

c l e a r l y t h a t i f t h e f o o t p l a t e w e r e r e m o v e d u n d e r t h e s e b u l e i s e v i d e n t . )

Fi CHAPTER 14

Lasers in Otologic Surgery

T h e w o r d l a s e r i s a n a c r o n y m for l i g h t a m p l i f i c a ­

t i o n b y s t i m u l a t e d e m i s s i o n o f r a d i a t i o n . I n t h e e a r l y

2 0 t h c e n t u r y A l b e r t E i n s t e i n p r e d i c t e d t h a t t h i s f o r m

o f e n e r g y e x i s t e d . I t w a s n o t u n t i l 1 9 6 0 t h a t T h e o d o r e

M a i m o n d e v e l o p e d t h e f i rs t w o r k i n g l a s e r , m a d e o f

a r u b y c r y s t a l . N e x t , t h e g a s l a s e r w a s d e v e l o p e d b y

A l e c J a v o n i n 1 9 6 1 . F r o m t h e s e e a r l y l a s e r s h a v e

c o m e t h e m a n y a d v a n c e d m o d e l s i n m e d i c a l u s e

t o d a y .

A n u m b e r o f l a s e r s y s t e m s a r e c u r r e n t l y a v a i l a b l e

f o r u s e i n t h e h e a d a n d n e c k a r e a . T h e a u t h o r s fee l

t h a t t h e v i s i b l e - w a v e l e n g t h l a s e r s — t h e a r g o n a n d t h e

K T P - 5 3 2 — a r e b e s t s u i t e d for o t o l o g i c w o r k .

T h e s e v i s i b l e - w a v e l e n g t h l a s e r s a r e m o s t u s e f u l

f o r a n u m b e r o f r e a s o n s :

1 . T h e y a l l o w for e n e r g y t r a n s m i s s i o n t h r o u g h

f i b e r o p t i c c a b l e s . T h e r e f o r e , n o a r t i c u l a t i n g , b u l k y

a r m s a r e n e e d e d a n d d e l i v e r y o f t h e b e a m t o t h e

i n t r i c a t e s p a c e s o f t h e m i d d l e e a r i s m o r e e a s i l y

a c c o m p l i s h e d .

2 . T h e v i s i b l e - s p e c t r u m l a s e r s d o n o t n e e d a c a r ­

r i e r b e a m t o b e s e e n b y t h e n a k e d e y e . W i t h t h e C O ,

b e a m , w h i c h u s e s a n i n v i s i b l e w a v e l e n g t h , a c a r r i e r

b e a m i s n e e d e d i n o r d e r t o f o c u s t h e b e a m o n t h e

s u r g i c a l s i t e ; i f t h e s e b e a m s a r e n o t exact ly c o a x i a l , o r

i f t h e m i r r o r s o f t h e a r t i c u l a t i n g a r m a r e i m p e r f e c t l y

a l i g n e d , t h e s u r g i c a l b e a m m a y n o t b e d e l i v e r e d

p r e c i s e l y w h e r e i t i s n e e d e d .

3 . T h e v i s i b l e - w a v e l e n g t h b e a m s a r e r e a d i l y a b ­

s o r b e d b y p i g m e n t a n d n o t b y c l e a r f l u i d s , s o h e m o -

s t a s i s c a n b e a c c o m p l i s h e d .

4 . A l o n g w i t h f i b e r o p t i c c a p a b i l i t y a n u m b e r o f

h a n d p i e c e s h a v e b e e n d e v e l o p e d , a l l o w i n g t h e b e a m

t o b e d e l i v e r e d b y a n a l t e r n a t e m e t h o d . T h e h a n d

p i e c e i s h e l d l i k e a s c a l p e l , a n d t h e b e a m i s f o c u s e d

b y m o v i n g i t u p a n d d o w n .

T h e d e v e l o p m e n t o f t h e l a s e r i n o t o l o g i c s u r g e r y

h a s b e e n a r e m a r k a b l e a d v a n c e ; l i ke a n y s u r g i c i !

t o o l , h o w e v e r , i t m u s t b e u s e d c o r r e c t l y . U n d e r s t a n d

i n g t h e l a s e r i s a b s o l u t e l y e s s e n t i a l , a n d p r o p e -

t r a i n i n g t h r o u g h a " h a n d s - o n " c o u r s e i s n e c e s s a r

b e f o r e o n e c a n e f f i c i e n t l y a n d s a f e l y u s e t h i s n e v

t o o l .

I n d i s c u s s i n g t h e s u r g i c a l a p p l i c a t i o n s o f t h e l a s e r

t h r e e t e r m s m u s t b e d e f i n e d : power , spot size, a n c

pulse duration. T h e p o w e r o f t h e b e a m i s i t s e n e r g y

o u t p u t a n d i s m e a s u r e d i n w a t t s . S p o t s i z e r e f e r s t'/

t h e d i a m e t e r o f t h e b e a m , a n d c a n v a r y f r o m m i c r o n s

t o m i l l i m e t e r s . P u l s e d u r a t i o n i s t h e a m o u n t o f t i m i

i n w h i c h t h e b e a m a c t i v e l y p e r f o r m s i t s s u r g i c c

f u n c t i o n ; i t m a y b e m e a s u r e d i n m i l l i s e c o n d s o r i

m a y b e c o n t i n u o u s . Al l o f t h e s e f u n c t i o n s c a n b >

v a r i e d a t a n y t i m e fo r d i f f e r e n t s u r g i c a l n e e d s .

P o w e r d e n s i t y i s a n o t h e r c o n c e p t t h a t m u s t b -

u n d e r s t o o d . I t i s d e f i n e d a s t h e p o w e r p e r u n :

v o l u m e ( F i g . 1 4 - 1 / 1 ) . T h e p o w e r o f t h e l a s e r b e a m i

c o n s t a n t , b u t b y v a r y i n g t h e s p o t s i z e o f t h e b e a m a

t h e foca l p o i n t , t h e p o w e r d e n s i t y c a n b e s i g n i f i c a n t ! "

a l t e r e d . F o c u s i n g t h e b e a m t o a v e r y s m a l l s p o t s i z r :

g r e a t l y i n c r e a s e s t h e p o w e r d e n s i t y ; w i t h a l a r g e s p o *

s i z e t h e p o w e r d e n s i t y i s d e c r e a s e d . T h i s i s a c r u c i a '

c o n c e p t i n l a s e r s u r g e r y a n d i s v i t a l i n u n d e r s t a n d s ; ,

t h e s u r g i c a l r a m i f i c a t i o n s o f t h e l a s e r .

T h e s u r g i c a l e f f e c t s o f t h e l a s e r b e a m a r e t i s s u e

c u t t i n g , t i s s u e c o a g u l a t i o n , a n d t i s s u e v a p o r i z a t i o n

( F i g . 14— I S ) . T h e y c a n b e a c h i e v e d b y m a n i p u l a t i n g

t h e s p o t s i z e o f t h e b e a m a n d v a r y i n g t h e p o w e r .

C u t t i n g o f t i s s u e r e q u i r e s t h e h i g h e s t p o w e r d e n s i t y ,

s o a v e r y s m a l l s p o t s i z e a n d l a r g e a m o u n t s o f p o w e r

a r e u s e d . F o r v a p o r i z a t i o n o f t i s s u e , full p o w e r i ;

u s e d w i t h a l a r g e r s p o t s i z e ; t h e d e p t h o f v a p o r i z a t i o n

c a n b e c o n t r o l l e d . C o a g u l a t i o n r e q u i r e s a l a r g e s p o t

L a s e r s i n O t o l o g i c S u r g e r y 273

. Power Power density =

Spot size

CUTTING VAPORIZATION COAGULATION

Small spol Large spol Large spol HiQh power High power Low power

FIGURE 14-1.

s i z e a n d a l o w p o w e r s e t t i n g . C o a g u l a t i o n o f v e s s e l s

c a n o n l y b e a c c o m p l i s h e d w i t h v i s i b l e - w a v e l e n g t h

l a s e r s ( a r g o n a n d K T P - 5 3 2 ) a n d n o t w i t h t h e C 0 2

l a s e r .

A c t u a l m a n i p u l a t i o n o f t h e b e a m i s d o n e b y t h e

s u r g e o n . T h e s p o t s i z e c a n b e a l t e r e d i n t w o w a y s .

W i t h t h e b e a m d e l i v e r y d e v i c e a t t a c h e d d i r e c t l y t o

t h e m i c r o s c o p e , t h e s p o t s i z e i s c h a n g e d b y a r h e o ­

s t a t - t y p e d e v i c e o n t h e m i c r o s c o p e ; w h i l e d i r e c t l y

v i s u a l i z i n g t h e b e a m , t h e s u r g e o n c a n v a r y t h e d i ­

a m e t e r o f t h e b e a m a s n e e d e d . T h e h a n d - h e l d d e l i v ­

e r y s y s t e m f o c u s e s a s t h e h a n d p i e c e i s m o v e d u p

a n d d o w n w h i l e t h e b e a m i s w a t c h e d a t t h e s u r g i c a l

s i t e . P u l s e d u r a t i o n a n d p o w e r a r e s e t o n t h e m a c h i n e

i t s e l f o r b y a r e m o t e c o n t r o l a t t h e o p e r a t i n g t a b l e .

T h e b e a m i s a c t i v a t e d b y a f o o t p e d a l .

Laser Stapedotomy

T h i s s e c t i o n d e s c r i b e s a p p l i c a t i o n s o f t h e l a s e r i n

t h e m i d d l e e a r , b u t t h e p r i n c i p l e s a n d t e c h n i q u e s

a l s o a p p l y t o m a s t o i d w o r k . S p e c i f i c a p p r o a c h e s t o

t h e s u r g i c a l s i t e ( i n c i s i o n s , f l a p s , a n d s o o n ) h a v e

b e e n d e s c r i b e d e l s e w h e r e . T h e d i s c u s s i o n wi l l f o c u s

2 7 4 L a s e r s i n O t o l o g i c S u r g e r y

o n l y o n l a s e r a p p l i c a t i o n s t o t i s s u e s ; a n y s p e c i f i c

a p p r o a c h e s t h a t a r e c a l l e d for a r e e x p l a i n e d .

Highlights

1 . G o o d l o c a l a n e s t h e s i a

2 . C o o d h e m o s t a s i s .

3 . R e m o v a l o f t h e s c u t u m .

4 . K n o w l e d g e a b l e n u r s i n g a s s i s t a n t s

5 . S u p e r i o r i n s t r u m e n t a t i o n

6 . U s e o f a s t a p e s h o l d e r .

7 . P r e s e r v a t i o n o f t h e c h o r d a t y m p a n i .

8 . V i s u a l i z a t i o n o f t h e p y r a m i d a l p r o c e s s a n d t h e

f ac i a l n e r v e .

9 . U n d e r s t a n d i n g o f l a s e r t e c h n i q u e s a n d u s e .

1 0 . C o m p l e t e v i s u a l i z a t i o n o f t h e o s s i c l e s .

Pitfalls

1 . F o r m i n g b l e b s i n t h e e x t e r n a l a u d i t o r y c a n a l

w h i l e i n j e c t i n g

2 . T e a r i n g t h e t y m p a n i c m e m b r a n e d u r i n g e l e v a ­

t i o n .

3 . I n a d e q u a t e e x p o s u r e .

4 . T e a r i n g t h e c h o r d a t y m p a n i .

5 . I n e x p e r i e n c e d s c r u b n u r s e .

6 . I n j u r i n g t h e facial n e r v e .

7 . P l a c i n g t h e p r o s t h e s i s t o o d e e p i n t h e o v a l

w i n d o w .

Procedure

T h e l a s e r s t a p e d o t o m v i s a v e r v s u c c e s s f u l a n d

e f f i c i e n t p r o c e d u r e . I n i t i a l l y t h e e a r i s p r e p a r e d a n d

d r a p e d i n t h e u s u a l f a s h i o n . A l l s t a p e d o t o m i e s a r e

d o n e u n d e r l o c a l a n e s t h e s i a ; t h e a u t h o r s u s e 2 %

l i d o c a i n e w i t h 1 : 2 0 , 0 0 0 e p i n e p h r i n e . A s t a n d a r d f o u r -

q u a d r a n t i n j e c t i o n i s m a d e w i t h a 2 7 - g a u g e n e e d l e .

T h e e a r i s t h e n i r r i g a t e d w i t h p o v i d o n e - i o d i n e ( B e -

t a d i n e ) t h r o u g h a b u l b s y r i n g e .

A s t a n d a r d s t a p e s f l ap i s e l e v a t e d w i t h a r o u n d

k n i f e . A s e m i c i r c u l a r i n c i s i o n i s m a d e s t a r t i n g a t t h e

6 o ' c l o c k p o s i t i o n , t r a v e l i n g u p t h e p o s t e r i o r c a n a l

w a l l , a n d e n d i n g a t t h e 1 2 o ' c l o c k p o s i t i o n j u s t a b o v e

t h e s h o r t p r o c e s s o f t h e m a l l e u s . T h e f lap i s e l e v a t e d

t o t h e a n n u l u s a n d t h e m i d d l e e a r i s e n t e r e d i n t he

u s u a l f a s h i o n . T h e c h o r d a t y m p a n i n e r v e i s i d e n t i f i e d

a n d p r e s e r v e d

T h e s t a p e s f lap i s r o t a t e d a n t e r i o r l y u n t i l t h j

p o s t e r i o r b o r d e r o f t h e m a l l e u s i s d i r e c t l y v i s u a l i z e d

T h e b o n y s c u t u m i s t h e n r e m o v e d un t i l t h e fac ia l

n e r v e i s v i s u a l i z e d a b o v e t h e s t a p e s a n d t h e p y r a m ­

ida l p r o c e s s o f t h e s t a p e d i a l t e n d o n i s i d e n t i f i e d

p o s t e r i o r l y . I t i s v e r y i m p o r t a n t t o v i s u a l i z e t h e i r

t w o s t r u c t u r e s t o e n s u r e a d e q u a t e w o r k i n g r o o m .

M a n i p u l a t i o n o f t h e m a l l e u s a n d i n c u s i s t h e i .

d o n e t o r u l e o u t f i x a t i o n o f e i t h e r s t r u c t u r e a s t h •

c a u s e o f t h e c o n d u c t i v e h e a r i n g l o s s . A t t e n t i o n I •

n o w f o c u s e d o n t h e s t a p e s ; a g a i n , m a n i p u l a t i o n wiMi

a s m a l l r i g h t - a n g l e d h o o k i s d o n e t o c o n f i r m f i x a t i o n

T h e i n c u s - s t a p e s j o i n t i s s e p a r a t e d . T h e s t a p e s h o l d , ?

i s t h e n b r o u g h t i n t o t h e f i e ld .

W i t h a d j u s t m e n t o f t h e l a s e r s p o t s i z e a n d b e a -

p a r a m e t e r s d o n e p r e o p e r a t i v e l y , t h e a c t u a l l a s e i

w o r k b e g i n s . T h e s t a p e d i a l t e n d o n i s f o c u s e d o n a n c

v a p o r i z e d , u s i n g t h e l a s e r a t 2 . 0 w a t t s o f p o w e r a r o

a p u l s e d b e a m o f 0.;1 s e c o n d . T h e b e a m i s s h a r p ' ;

f o c u s e d o n t h e t e n d o n b y a " j o y s t i c k " m o u n t e d c r

t h e m i c r o s c o p e , a n d i s f i r ed b y a f o o t c o n t r o l w h e n

t h e o p e r a t o r i s r e a d y . T h e s m o k e p l u m e i s d r a w r

a w a y b y a N o . 2 2 s u c t i o n t ip h e l d i n t h e o p e r a t o r ?

le f t h a n d ( F i g . 1 4 - 2 A ) .

O n c e t h e t e n d o n h a s b e e n v a p o r i z e d , a m e a s u r e

m e n t i s t a k e n f r o m t h e l a t e r a l s u r f a c e o f t h e i n c u s ::•

t h e f o o t p l a t e o f t h e s t a p e s . A d d i n g 0 . 5 m m t o t h s

m e a s u r e m e n t g i v e s t h e p r o p e r l e n g t h for t h e p r o : -

t h e s i s . T h i s l e n g t h wi l l v a r y w i t h t h e t y p e o f p r e -

t h e s i s , p o i n t o f m e a s u r e m e n t , a n d o t h e r f a c t o r s . T h - '

l a s e r b e a m i s t h e n f o c u s e d on t h e p o s t e r i o r c r u s t i

t h e s t a p e s A g a i n , w i t h a p u l s e d b e a m a n d ( h e s a m •

p o w e r s e t t i n g s , t h e c r u s i s l a s e d a w a y ( F i g . 1 4 - 2 8 ) .

T w o s u g g e s t i o n s m a y b e h e l p f u l a t t h i s s t a g e :

1 . I f t h e h e m e i s v e r y w h i t e , v a p o r i z a t i o n m a y r>.»

s l o w b e c a u s e t h e b e a m i s a b s o r b e d b v p i g m e n t . / .

d r o p o f b l o o d , b o n e c h a r , o r e v e n g e n t i a n v i o l e t w i l l

h e l p g r e . i t l v . O n c e t h e in i t i a l d a r k h o n v c h a r d e v e l

o p s . v a p o r i z a t i o n p r o c e e d s v e r v q u i c k l v .

2 . W h e n e x c e s s c h a r b u i l d s u p a r o u n d t h e b o n e

v a p o r i z a t i o n m a y a g a i n b e s l o w . T h e c h a r s h o u l d b i

g e n t l y c h i p p e d a w a y w i t h a s m a l l r i g h t - a n g l e d p i c k

O n c e t h e p o s t e r i o r c r u s h a s b e e n v a p o r i z e d , th*

a n t e r i o r c r u s i s a d d r e s s e d . O f t e n i t c a n b e s e e i

d i r e c t l y a n d r e m o v e d i n t h e s a m e w a y a s t h e p o s t e

r io r c r u s . W h e n t h e a n t e r i o r c r u s c a n n o t b e d i r e c t l y

v i s u a l i z e d b e c a u s e o f t h e b o d y o f t h e I n c u s , a s p e

c i a l l y d e s i g n e d m i r r o r i s n e e d e d t o r e f l ec t t h e b e a m

o n t o i t . T h e b e a m i s f irst f o c u s e d o n t h e p r o m o n t o r v

j u s t a n t e r i o r t o t h e a n t e r i o r c r u s . T h e m i r r o r i s

i n t r o d u c e d u n t i l t h e a n t e r i o r c r u s i s r e f l e c t e d . T h e

b e a m i s t h e n b o u n c e d o f f t h e m i r r o r o n t o t h e a n t e r i o ' "

c r u s u n t i l i t i s v a p o r i z e d ( F i g . 1 4 - 2 C ) .

A t t e n t i o n i s t h e n t u r n e d t o t h e f o o t p l a t e o f t h e

s t a p e s . T h e a u t h o r s u s e e i t h e r a 0 . 8 - m m o r a 0 . 6 - m m

L a s e r s i n O t o l o g i c S u r g e r y 275

FIGURE 14-2.

276 L a s e r s i n O t o l o g i c S u r g e r y

Laser Applications in the Middle Ear

I n i t i a l l y r e s t r i c t e d t o s t a p e d o t o m y p r o c e d u r e s , u s e

o f t h e l a s e r h a s b e e n e x p a n d e d t o i n c l u d e e v e r y c a s e

i n t h e a u t h o r s ' o t o l o g i c p r a c t i c e . I t h a s p r o v e d t o b e

e x t r e m e l y u s e f u l i n r e c o n s t r u c t i o n a n d c h o l e s t e a t o m a

w o r k i n t h e m i d d l e e a r a n d m a s t o i d .

Ossicles

T h e l a s e r h a s b e e n v e r y b e n e f i c i a l i n w o r k a r o u n d

t h e o s s i c l e s . S i n c e m a n i p u l a t i o n o f t h e o s s i c l e s a n d

c o r r e s p o n d i n g t r a u m a p o t e n t i a l l y m a y c a u s e s e n s o ­

r i n e u r a l h e a r i n g l o s s a n d o s s i c u l a r d i s a r t i c u l a t i o n , i *

i s d e s i r a b l e t o m i n i m i z e t h i s m a n i p u l a t i o n . T h e

h i g h l y f o c u s e d b e a m o f t h e l a s e r c a n v i r t u a l l y e l i m i ­

n a t e m a n u a l t r a u m a i n v o l v i n g t h e o s s i c l e s .

T h e l a s e r i s e s p e c i a l l y u s e f u l i n t h e p r e s e n c e o f

c h o l e s t e a t o m a o r a d h e s i o n s a r o u n d t h e s t a p e s o r i r

t h e o v a l w i n d o w n i c h e . W i t h v e r y a d h e r e n t d i s e a s e

d i s a r t i c u l a t i o n w i t h r e s u l t a n t p e r i l y m p h l e a k i s a t

w a y s a h a z a r d . U s i n g a f i n e l y f o c u s e d b e a m o f s h o r t

p u l s e d u r a t i o n ( 0 . 1 t o 0 . 3 s e c o n d s ) a n d l o w p o w e r ( i

t o 3 w a t t s ) , d i s e a s e c a n b e v a p o r i z e d w i t h o u t t r a u m a

t o t h e n e a r b y o s s i c l e s .

A n o t h e r u s e fo r t h e l a s e r i s i n t h e e a r f i l l ed w i t h

a d h e s i o n s a n d p o l y p o i d m a t e r i a l . S e t t i n g t h e b e a m

for c o a g u l a t i o n p a r a m e t e r s , s u r f a c e c o a g u l a t i o n o f

t h e s e s m a l l v e s s e l s c a n b e a c c o m p l i s h e d . E l i m i n a t i n g

o r r e d u c i n g t h i s n u i s a n c e b l e e d i n g p e r m i t s a s a f e r

a n d f a s t e r p r o c e d u r e . I n a d d i t i o n , v a p o r i z a t i o n o f

t h e a d h e s i o n s c a n b e a c c o m p l i s h e d w i t h a d j u s t m e n t

o f t h e b e a m p a r a m e t e r s . A g a i n , t h i s e l i m i n a t e s m u c h

o f t h e v i b r a t o r y t r a u m a , r e d u c e s b l e e d i n g , a n d a l l o w s

t h e s u r g e o n t o r e m o v e t h e a d h e s i o n s l a y e r b y l a y e r

( F i g . 1 4 — 3 8 ) . T h i s p r e c i s i o n , e s p e c i a l l y i n t h e d e p t h s

o f t h e o v a l w i n d o w w i t h d i s e a s e a r o u n d t h e s t a p e s

g r e a t l y e n h a n c e s t h e a b i l i t y t o r e m o v e t i s s u e w i t h o u

t r a u m a t o t h e s u r r o u n d i n g n o r m a l a n a t o m i c s t r u c

t u r e s .

A n o t h e r i d e a l s i t u a t i o n for L i - . l t w o r k i s e r o s i o r

o f t h e l e n t i c u l a r p r o c e s s o f t h e i n c u s . A l t h o u g h

e r o d e d a n d l a c k i n g a b o n y c o n n e c t i o n w i t h the

s t a p e s , t h e l e n t i c u l a r p r o c e s s o f t e n h a s e n o u g h b o n t

left t o m a k e r e c o n s t r u c t i o n d i f f i c u l t . U s i n g t h e l a s e r

t h e s u r g e o n c a n v a p o r i z e t h e b o n e q u i c k l y , s h a r p l y ,

a n d a t r a u m a t i c a l l y t o a l l o w m o r e r o o m ( o r t h e r e c o n ­

s t r u c t i v e p r o c e d u r e ( F i g . 1 4 - 3 / 1 ) .

T h e l a s e r a l s o i s q u i t e u s e f u l i n t y m p a n i c m e m ­

b r a n e w o r k . F r e s h e n i n g t h e e d g e s o f a p e r f o r a t i o n i r

p r e p a r a t i o n for a g r a f t c a n b e d o n e e a s i l y a n d q u i c k l y .

A p u l s e d o r c o n t i n u o u s b e a m f o c u s e d o n t h e p e r i p l v

e r y o f t h e p e r f o r a t i o n c a n b e u s e d t o r e m o v e t h f

r o l l e d e d g e s o f t h e p e r f o r a t i o n ( F i g . 1 4 - 3 C ) .

W h e n e l e v a t i o n o f t h e p e r i o s t e u m o f t h e m a l l e u c

i s r e q u i r e d i n g r a f t i n g t e c h n i q u e s , t h e a r e a a r o u n d

t h e u m b o i s a l w a y s v e r y a d h e r e n t . T u g g i n g a n d

p u l l i n g o f t h i s t i s s u e c a u s e s c o n s i d e r a b l e v i b r a t o r y

t r a u m a t h r o u g h o u t t h e o s s i c u l a r c h a i n . O n c e

a g a i n , t i s s u e c a n b e l a s e d a w a y w i t h o u t t r a u m a ( F i g

1 4 - 3 D ) .

L a s e r s i n O t o l o g i c S u r g e r y 2 7 7

FIGURE 14-3.

o p e n i n g i n t o t h e i n n e r e a r ; t h e f o r m e r i s p r e f e r r e d

u n l e s s t h e r e i s n o t e n o u g h r o o m . A t e m p l a t e i s p l a c e d

o n t h e f o o t p l a t e , m a k i n g a v i s u a l i m a g e o f t h e 0 . 8 -

m m s i t e ( F i g . 1 4 - 2 D ) . T h e l a s e r i s t u r n e d t o 1 .8 w a t t s

a n d a 0 . 1 - s e c o n d p u l s e d b e a m . A r o s e t t e p a t t e r n i s

m a d e o n t h e f o o t p l a t e , c o r r e s p o n d i n g t o t h e 0 . 8 - m m

s t a p e d o t o m y o p e n i n g . U s u a l l y o n e p u l s e w i l l o p e n

t h e f o o t p l a t e . I t i s i m p o r t a n t t o o v e r l a p t h e s e l a s e r

" h i t s , " b e c a u s e t h e c h a r f r o m e a c h p r e v i o u s hi t wi l l

a b s o r b t h e h e a t a n d a l l o w for b e t t e r v a p o r i z a t i o n

T h e t e m p l a t e i s r e i n t r o d u c e d t o e n s u r e t h a t t h e

o p e n i n g i s t h e p r o p e r s i z e .

T h e p r o s t h e s i s i s t h e n p o s i t i o n e d o v e r t h e i n c u s

a n d i n t o t h e s t a p e d o t o m y o p e n i n g a n d c r i m p e d i n t o

p o s i t i o n ( F i g . 1 4 — 2 £ ) . T h e p a r t o f t h e p r o s t h e s i s t h a t

f i t s i n t o t h e v e s t i b u l e i s e x a c t l y 1 m m i n l e n g t h ; w h e n

p r o p e r l y p o s i t i o n e d , h a l f o f it , o r 0 . 5 m m , s i t s i n t h e

v e s t i b u l e . S i n c e t h i s s e c t i o n o f t h e p r o s t h e s i s i s o n l y

1 m m l o n g , i t i s e a s y t o j u d g e t h e c o r r e c t d e p t h .

T w o a d d i t i o n a l s u g g e s t i o n s a r e r e l e v a n t h e r e ;

1 . I f s o m e o f t h e l a s e r h i t s d o n o t c a u s e p e r i l y m p h

t o f l o w a n d d o n o t e x t e n d all t h e w a y t h r o u g h t h e

f o o t p l a t e b o n e , t h i s i s n o t c a u s e for a l a r m . I f m o s t o f

t h e h i t s g o t h r o u g h t h e b o n e , t h e p r o s t h e s i s wi l l

e a s i l y b r e a k t h r o u g h t h e r e m a i n i n g o n e s

2 . S o m e t i m e s a s m a l l a m o u n t o f r e s i d u a l c h a r

f r o m t h e v a p o r i z a t i o n i s lef t o n t h e f o o t p l a t e . I t i s

n o t n e c e s s a r y t o r e m o v e t h i s .

O n c e t h e p r o s t h e s i s i s c o r r e c t l y p o s i t i o n e d a n d

c r i m p e d , t h e t y m p a n i c m e m b r a n e i s r e p o s i t i o n e d .

A l l s o u n d i n t h e o p e r a t i n g s u i t e ( m o n i t o r s , f a n s ,

l a s e r s , a n d s o o n ) i s r e d u c e d , a n d t h e p a t i e n t i s a s k e d

t o c o u n t n u m b e r s t o o b t a i n a s u b j e c t i v e h e a r i n g l e v e l .

W h e n t h e s u r g e o n i s s a t i s f i e d w i t h t h e h e a r i n g l e v e l ,

t h e f o o t p l a t e i s r e v i s u a l i z e d . I f t h e p r o s t h e s i s i s f i r m l y

f i x e d i n p o s i t i o n , o n e o r t w o s m a l l d r o p s o f a u t o g e ­

n o u s b l o o d a r e i n s t i l l e d i n t h e o v a l w i n d o w t o a c t a s

a s e a l . T h e f l ap i s t h e n r e p o s i t i o n e d a n d p a c k e d w i t h

G e l f o a m , a m a s t o i d d r e s s i n g i s p l a c e d , a n d t h e p a ­

t i e n t i s t a k e n t o t h e r e c o v e r y r o o m .

278 L a s e r s i n O t o l o g i c S u r g e r y

A s m e n t i o n e d p r e v i o u s l y , t h e a r g o n a n d K T P - 5 3 2

l a s e r s a r e r e a d i l y a b s o r b e d b y p i g m e n t a n d h e m o g l o ­

b i n . B e c a u s e o f t h i s a f f i n i t y , h e m o s t a s i s o f s m a l l

m i d d l e e a r c l e f t b l e e d i n g c a n o f t e n b e a c c o m p l i s h e d .

W i t h a l a r g e s p o t s i z e , p u l s e d b e a m , a n d l o w p o w e r ,

n u i s a n c e b l e e d i n g f r o m m u c o s a l a r e a s c a n b e c o n ­

t r o l l e d . A g a i n , t h e s p e e d a n d p r e c i s i o n o f t h e l a s e r

i n h e m o s t a s i s l e n d s i t s e l f g r e a t l y t o t h e e n h a n c e m e n t

o f r e c o n s t r u c t i v e w o r k .

T h e l a s e r i s i d e a l l y s u i t e d for r e p a i r o f a f i xed

m a l l e u s . T h e d i f f i cu l t y i n d r i l l i n g a r o u n d t h e o s s i c l e s

I n t h e a t t i c i s g r e a t l y r e d u c e d . A l s o , d i s a r t i c u l a t i o n

o f t h e i n c u s - s t a p e s j o i n t i s n o t n e e d e d b e c a u s e o f t h e

a t r a u m a t i c b o n e v a p o r i z a t i o n . A s t a n d a r d p o s t a u r i c -

u l a r i n c i s i o n i s m a d e a n d a n a t t i c o t o m y i s p e r f o r m e d

( d e s c r i b e d e l s e w h e r e i n t h i s b o o k ) . D r i l l i n g i s d o n e

u n t i l t h e f i x e d o s s i c l e s a r e i d e n t i f i e d . I n t h e a u t h o r s '

e x p e r i e n c e , t h e d i f f i c u l t y l i e s i n f r e e i n g t h e f i x a t i o n ,

w h i c h i s u s u a l l y a n t e r i o r a n d m e d i a l t o t h e m a l l e u s

a n d i n c u s . I t i s e x t r e m e l y d i f f i c u l t t o dr i l l t h i s b o n e

a w a y ; c u r e t t i n g a l s o i s c r u d e a n d d i f f i c u l t . O n c e t h e

f i x a t i o n i s v i s u a l i z e d , t h e l a s e r p r o v i d e s a n i dea l w a y

t o r e m o v e t h e b o n e w i t h o u t t r a u m a t o t h e o s s i c l e s .

A p u l s e d o r c o n t i n u o u s b e a m s h a r p l y f o c u s e d o n t h e

b o n y f i x a t i o n v a p o r i z e s t h e b o n e , a l l o w i n g f ree m o ­

b i l i t y o f t h e c h a i n ( F i g . 1 4 - 3 E ) . A s m a l l p i e c e o f

S i l a s t i c i s t h e n i n s e r t e d b e t w e e n t h e o s s i c l e s a n d t h e

a r e a o f f i x a t i o n t o h e l p p r e v e n t b o n e r e g r o w t h .

Summary

T h e l a s e r h a s m a r k e d l y r e d u c e d t h e d e g r e e o f

v i b r a t o r y t r a u m a t o t h e o s s i c l e s a n d t h u s t o t h e i n n e r

e a r f l u i d s . B y m i n i m i z i n g t r a u m a , t h e s u r g e o n re ­

d u c e s t h e c h a n c e s o f i a t r o g e n i c s e n s o r i n e u r a l h e a r i n g

l o s s . T h e p r e c i s i o n o f t h e b e a m a l l o w s t h e s u r g e o n

t o r e a c h a r e a s o f t h e m i d d l e e a r c l e f t s a f e l y , q u i c k l y ,

a n d w i t h l e s s p o t e n t i a l for i n j u r y t o t h e p a t i e n t . A

s e c o n d m a j o r a d v a n t a g e l i e s i n t h e h e m o s t a t i c p r o p ­

e r t i e s o f t h e v i s i b l e - s p e c t r u m l a s e r . T h e c o n f i n e s o f

t h e m i d d l e e a r h a v e a l w a y s b e e n d i f f i c u l t t o r e a c h

for c o n v e n t i o n a l c o a g u l a t i o n . T h e p i g m e n t - a b s o r p ­

t i v e p r o p e r t i e s o f t h e v i s i b l e - s p e c t r u m b e a m s h a v e

g r e a t l y e n h a n c e d t h i s p r o c e d u r e . T h e s e t w o f e a t u r e s

o f t h e l a s e r h a v e a d d e d a n e w d i m e n s i o n t o o t o l o g i c

s u r g e r y .

Neurotology and the Laser

|: T h e l a s e r a l s o i s u s e d e x t e n s i v e l y i n n e u r o t o ! o j ; i c

p r a c t i c e , a n d h a s b e e n a n i n v a l u a b l e a d d i t i o n , t o

a c o u s t i c n e u r o m a w o r k . I t i s u s e d for t h r e e f u n c t i o ; s :

( 1 ) h e m o s t a s i s , ( 2 ) v a p o r i z a t i o n o f t h e t u m o r , a n d i 3 )

t u m o r c u t t i n g for r e m o v a l .

Procedure

T u m o r e x p o s u r e i s a c c o m p l i s h e d b y t h e s t a n d a r d

a p p r o a c h e s t o t h e p o s t e r i o r a n d m i d d l e f o s s a , w h i c h

h a v e b e e n d e s c r i b e d e l s e w h e r e . I n t h e t r a n s l a b y r i n ­

t h i n e a p p r o a c h , t h e i n t e r n a l a u d i t o r y c a n a l b o m i s

t h i n n e d o n i t s s u p e r i o r , p o s t e r i o r , a n d i n f e r i o r b o r ­

d e r s . O n c e t h e e g g s h e l l - t h i n b o n e i s le f t , t h e l a s e r j s

u s e d i n i t i a l l y for s u r f a c e c o a g u l a t i o n ( F i g . 1 4 - 4 . " ) .

T h e a r e a o v e r t h e fac ia l n e r v e i n t h e a n t e r o s u p e r i > r

q u a d r a n t i s c o v e r e d w i t h C o t t o n o i d for p r o t e c t i o n .

T h e l a s e r i s u s e d a t a p p r o x i m a t e l y 4 to 6 w a t t s i f

p o w e r w i t h a p u l s e d b e a m a n d a l a r g e s p o t s i z r .

B e c a u s e o f t h e b e a m ' s a f f i n i t y for p i g m e n t , i t i s

a b s o r b e d b y t h e h e m o g l o b i n . C o a g u l a t i o n i s a c c o m ­

p l i s h e d o v e r t h e s u r f a c e o f t h e t u m o r a n d t h r o u g h

t h e e g g s h e l l - t h i n b o n e . S u r f a c e c o a g u l a t i o n o f t h e

s m a l l c a p i l l a r i e s b e f o r e o p e n i n g t h e d u r a o f t he

i n t e r n a l a u d i t o r y c a n a l r e d u c e s a n d s o m e t i m e s c o m ­

p l e t e l y p r e v e n t s n u i s a n c e b l e e d i n g f r o m s m a l l d u r i l

t u m o r v e s s e l s . O n c e s u r f a c e c o a g u l a t i o n i s a c c o m ­

p l i s h e d , t h e fac ia l n e r v e i s i d e n t i f i e d i n t h e i n t e r n i l

a u d i t o r y c a n a l . D i s s e c t i o n i s j c c o m p l i s h e d i n t h e

c a n a l in t h e s t a n d a r d f a s h i o n . A f t e r t h e f ac i a l ne ' e

i s i d e n t i f i e d a n d C o t t o n o i d i s p a c k e d a r o u n d i t -dr

p r o t e c t i o n , t h e t u m o r b u l k i n t h e c a n a l i s v a p o r L e c

a w a y ( F i g . 1 4 - 4 B ) . B y m a n i p u l a t i n g t h e p o w e r i e t

t i n g s a n d b e a m s p o t s i z e , t u m o r c a n b e v a p o r b e c

s a f e l y a n d q u i c k l y , o f t e n w i t h m i n i m a l b l e e d i n g . '

S t a n d a r d p o s t e r i o r f o s s a p r o c e d u r e s — p r o t e c t ' j n

o f o t h e r c r a n i a l n e r v e s , t h e c e r e b e l l u m , a n d h e

b r a i n s t e m w i t h C o t t o n o i d — a r e f o l l o w e d o n c e t u n o r

r e m o v a l i n t h e a n g l e i s b e g u n . T h e f ac i a l n e r v e i s

a l w a y s k e p t i n v i e w b u t i s p r o t e c t e d w i t h C o t t o n o . d

T u m o r r e m o v a l b y v a p o r i z a t i o n i s d o n e a l m o s t e x c tt-

s i v e l y w i t h t h e l a s e r i n t h e c e r e b e l l o p o n t i n e a n g l e .

T h e a u t h o r s u s e full p o w e r ( 8 t o 1 0 w a t t s ) w i t t a

L a s e r s i n O t o l o g i c S u r g e r y 279

FIGURE 14-4.

280 L a s e r s i n O t o l o g i c S u r g e r y

c o n t i n u o u s b e a m a n d a m e d i u m s p o t s i z e . T u m o r

r e m o v a l i s d o n e f r o m t h e i n t e r i o r o f t h e t u m o r ,

i n i t i a l l y k e e p i n g t h e c a p s u l e i n t a c t . S u c t i o n i s u s e d

t o d r a w a w a y t h e s m o k e p l u m e f r o m t h e v a p o r i z a t i o n

p r o c e s s . A s i t s i n t e r i o r i s v a p o r i z e d , t h e t u m o r c a p ­

s u l e c o l l a p s e s a n d f u r t h e r d i s s e c t i o n o f t h e c a p s u l e

f r o m s u r r o u n d i n g s t r u c t u r e s c a n b e a c c o m p l i s h e d .

W i t h v e r y l a r g e t u m o r s , t h e t u m o r i t s e l f c a n b e c u t

a w a y w i t h t h e l a s e r . T h e b e a m p a r a m e t e r s a r e

c h a n g e d t o a v e r y s h a r p f o c u s w i t h full p o w e r a n d

c o n t i n u o u s d u r a t i o n . U s i n g t h i s b e a m , t u m o r b u l k i s

c u t a w a y e a s i l y w i t h m i n i m a l b l e e d i n g ( F i g . 1 4 - 4 C ) .

T h e t e c h n i q u e s a n d u s e s o f t h e l a s e r i n t h e s u b ­

o c c i p i t a l a p p r o a c h a r e s i m i l a r . A n a d d i t i o n a l s t e p i s

t h a t t h e d u r a o v e r t h e p o s t e r i o r l ip o f t h e i n t e r n a l

a u d i t o r y c a n a l i s l a s e d a w a y ; a g a i n , i t c a n b e r e m o v e d

q u i c k l y a n d w i t h o u t b l e e d i n g , a n d l e s s t i m e i s n e e d e d

for b i p o l a r c a u t e r y o r d r i l l i n g .

S e c t i o n i n g o f t h e v e s t i b u l a r n e r v e c a n a l s o b e d o n e

w i t h t h e l a s e r . T h e n e r v e i s i s o l a t e d b y s t a n d a r d

t e c h n i q u e s , a n d t h e c o c h l e a r a n d fac ia l n e r v e s a r e

p r o t e c t e d w i t h C o t t o n o i d ; t h e v e s t i b u l a r n e r v e i s t h e t

v a p o r i z e d a w a y . I n t h i s c a s e , h o w e v e r , t h e a u t h o r a

feel t h a t c o n v e n t i o n a l s e c t i o n i n g w i t h s c i s s o r s i s j u t

a s e f f e c t i v e .

V a s c u l a r l e s i o n s , e s p e c i a l l y s m a l l g l o m u s t y m p a r -

i c u m t u m o r s , a l s o c a n b e d e b u l k e d w i t h t h e l a s e : .

S m a l l f e e d e r v e s s e l s a r e e a s i l y c o a g u l a t e d w i t h th";

v i s i b l e - s p e c t r u m b e a m . T h e c a p s u l e o f t h e t u m o r ;

c a u t e r i z e d w i t h l o w p o w e r s e t t i n g s a n d a d i f f u s e d

b e a m . T h i s u s e o f t h e l a s e r " t o u g h e n s " t h e c a p s u l e

a l l o w i n g for e a s i e r a n d s a f e r m a n i p u l a t i o n o f th ' i

t u m o r . L a r g e v e s s e l s c a n n o t b e c o a g u l a t e d w i t h t h r

b e a m , b u t b y r e d u c i n g t h e f e e d e r v e s s e l s , t u m o •

r e m o v a l i s f a c i l i t a t e d .

I n s u m m a r y , t h e l a s e r h a s p r o v e d t o b e a n i n v a !

u a b l e t o o l i n o t o l o g i c a n d n e u r o t o l o g i c w o r k . S t a m

d a r d t e c h n i q u e s a r e g r e a t l y f a c i l i t a t e d b y t h e l a s e r ; i f

i s p r e c i s e , f a s t , s a f e , a n d v e r y e f f i c i e n t , a n d w B

p r o b a b l y b e c o m e s t a n d a r d i n t h e n e a r f u t u r e . T h t

n e x t h u r d l e i n o t o l o g y i s t h e i n n e r e a r , a n d t h e l a s »

m a y b e o f b e n e f i t i n t h e n o t t o o d i s t a n t f u t u r e .

CHAPTER 15

Surgical Approach for Bone Conduction Hearing Devices

B o n e c o n d u c t i o n h e a r i n g d e v i c e s a r e i n a n e a r l y

p h a s e o f d e v e l o p m e n t , b u t a f i rs t g e n e r a t i o n i s n o w

a v a i l a b l e f o r c l i n i c a l u s e . T h i s a r e a o f o t o l o g y s h o u l d

w i t n e s s s i g n i f i c a n t p o s i t i v e c h a n g e s i n f u t u r e y e a r s .

C o n d u c t o r s a r e a v a i l a b l e i n t w o t y p e s , p e r c u t a ­

n e o u s a n d t r a n s c u t a n e o u s . T h i s c h a p t e r d e s c r i b e s

t h e s u r g i c a l t e c h n i q u e ( H o u g h ' s t e c h n i q u e ) for i m ­

p l a n t a t i o n o f t h e X o m e d a u d i a n t b o n e c o n d u c t o r .

T h i s b o n e c o n d u c t o r i s a t r a n s c u t a n e o u s d e v i c e

c o n s i s t i n g o f a n e x t e r n a l a n d a n i n t e r n a l c o m p o n e n t .

E x t e r n a l l y ( o u t s i d e t h e p a t i e n t ) , a m i c r o p h o n e re ­

c e i v e s s o u n d a n d c h a n n e l s i t t o a s o u n d p r o c e s s o r ;

t h i s d i r e c t s a n a m p l i f i e d s i g n a l a c r o s s t h e s k i n t o t h e

i m p l a n t ( t h e i n t e r n a l c o m p o n e n t ) , w h i c h i s s c r e w e d

i n t o t h e s k u l l . T h e a m p l i f i e d s i g n a l i s t r a n s m i t t e d b y

s k u l t v i b r a t i o n i n t o t h e i n n e r e a r a n d s o u n d i s p e r ­

c e i v e d . T h e e x t e r n a l a n d i n t e r n a l p a r t s o f t h e d e v i c e

a r e h e l d t o g e t h e r e l e c t r o m a g n e t i c a l l y . T h e s y s t e m i s

b a t t e r y o p e r a t e d .

T h i s d e v i c e c u r r e n t l y i s u s e d i n p a t i e n t s w i t h

e x t e r n a l o r m i d d l e e a r i m p a i r m e n t s w i t h g o o d b o n e

c o n d u c t i o n a n d s p e e c h d i s c r i m i n a t i o n w h o c a n n o t

b e n e f i t f r o m c o n v e n t i o n a l h e a r i n g a i d s ( o w i n g t o

c o n g e n i t a l m a l f o r m a t i o n s , c h r o n i c e x t e r n a l o t i t i s o r

o t h e r f a c t o r s ) . I n d i c a t i o n s for t h e d e v i c e w i l l b e

e x p a n d e d . S o m e b a s i c i n s t r u m e n t s ( X o m e d k i t ) a r e

r e q u i r e d i n o r d e r t o p o s i t i o n t h e i n t e r n a l r e c e i v e r i n

t h e s k u l l ; t h e y a r e s h o w n i n F i g u r e 1 5 - 1 .

Aim

T o e x p o s e i a s i t e i n t h e a r e a o f t h e l i n e a t e m p o r a l i s

for s a f e p l a c e m e n t o f t h e r e c e i v e r , w h i l e a l l o w i n g

a d e q u a t e s k i n c o v e r a g e a n d a p o s i t i o n for t h e e x t e r n a l

d e v i c e t h a t i s c o m f o r t a b l e a n d h a r m l e s s .

Procedure

A f t e r p r e p a r a t i o n a n d s h a v i n g o f t h e p o s t a u r i c u l a r

a r e a , t h e e a r i s s t e r i l e l y d r a p e d . A p o s t a u r i c u l a r l i n e

i s t r a c e d h o r i z o n t a l l y a t a l e v e l i m m e d i a t e l y s u p e r i o r

t o t h e t r a g u s . T h e r e c e i v e r ( i m p l a n t ) i s t o b e p l a c e d

b e h i n d t h e p o s t e r i o r e d g e o f t h e p i n n a . A p p r o x i ­

m a t e l y 1 5 t o 1 8 m m f r o m t h i s p o s t e r i o r e d g e a n d

i m m e d i a t e l y a b o v e t h e h o r i z o n t a l l i n e , t h e b u r h o l e

t e m p l a t e i s p o s i t i o n e d a n d t h e s i t e o f t h e r e c e i v e r

d e l i n e a t e d ( F i g , 1 5 - 2 4 ) .

A n i n c i s i o n s i t e i s t r a c e d a t l e a s t 1 c m p o s t e r i o r t o

t h e e d g e o f t h e r e c e i v e r a n d i n j e c t e d w i t h 2 % l i d o -

c a i n e ( X y l o c a i n e ) w i t h 1 : 1 0 0 , 0 0 0 e p i n e p h r i n e . T h e

i n c i s i o n i s d e e p e n e d d o w n t o t h e p e r i o s t e u m , a f lap

i s e l e v a t e d , a n d t h e l i n e a t e m p o r a l i s i s i d e n t i f i e d . I f

t h e s u b c u t a n e o u s t i s s u e s a r e t h i c k , t h e a r e a t h a t wil l

283Surgical Approach for Bone Conduction Hearing Devices

TIghtening tool

Deplh SlOp burs

Implant

Spanner attachmentFull tap

Guide cylinder

Template

Universal wrenell handle

Surgical Approach for Bone Conduction Hearing Devices282

fiGURE 15-1 FIGURE 15-2.

FIGURE 15-3.

S u r g i c a l A p p r o a c h for B o n e C o n d u c t i o n H e a r i n g D e v i c e s 285

c o v e r t h e r e c e i v e r i s t h i n n e d i n o r d e r t o p e r m i t

a d e q u a t e t r a n s c u t a n e o u s t r a n s m i s s i o n a n d m a g n e t i c

c o u p l i n g b e t w e e n t h e e x t e r n a l a n d i n t e r n a l d e v i c e s .

T h e a r e a w h e r e t h e r e c e i v e r w i l l b e p l a c e d i s

r e i d e n t i f i e d , m a r k e d , a n d e v e n e d w i t h a b u r ki t

w i t h o u t d r i l l i n g d e e p i n t o t h e b o n e ( F i g . 1 5 - 2 B ) .

( T h i s a r e a n e e d s d e p t h t o r e c e i v e t h e s c r e w o f t h e

i m p l a n t . )

U s i n g t h e l a r g e r b u r i n t h e ki t ( t h e b u r s h a v e a

d e p t h s t o p ) , t h e c e n t e r h o l e i s d r i l l e d ( F i g . 1 5 - 2 C ) . I f

a c e r e b r o s p i n a l f lu id l e a k o c c u r s , t h e s i t e i s s e a l e d

w i t h b o n e w a x a n d a n a d j a c e n t s i t e i s u s e d .

U s i n g t h e s m a l l b u r i n t h e s e t a n d t h e b u r h o l e

t e m p l a t e a s a g u i d e , t h r e e s m a l l c o n t r o l h o l e s a r e

d r i l l e d ( F i g . 1 5 - 2 D ) . T h e l a r g e r c e n t r a l h o l e i s d e s ­

t i n e d fo r t h e c e n t r a l s c r e w o f t h e i m p l a n t . T h e t h r e e

a d j a c e n t c o n t r o l h o l e s w i l l r e c e i v e t h e t h r e e p e g s o f

t h e g u i d e c y l i n d e r a n d i m p a r t s t a b i l i t y t o it.

T h e n e x t s t e p i s t o d e v e l o p a t h r e a d i n t h e c e n t e r

h o l e f o r t h e s c r e w o f t h e i m p l a n t . T h i s i s d o n e i n

t w o s t a g e s , u s i n g t h e " h a l f t a p " a n d " f u l l t a p "

i n s t r u m e n t s .

T h e g u i d e c y l i n d e r i s p l a c e d u p r i g h t . T h e t h r e e

p e g s a r e i n s e r t e d i n t h e c o r r e s p o n d i n g t h r e e h o l e s t o

k e e p t h e c y l i n d e r p e r p e n d i c u l a r t o t h e b o n e s u r f a c e .

T h e f i rs t t a p t o b e u s e d i s t h e h a l f t a p ; t h i s i s

t i g h t e n e d t o t h e u n i v e r s a l w r e n c h h a n d l e w i t h t h e

t i g h t e n i n g t o o l . T h e u n i v e r s a l w r e n c h ( w i t h t h e h a l f

t ap t i g h t e n e d t o i t) i s t h e n s l id t h r o u g h t h e g u i d e

c y l i n d e r a n d r o t a t e d c l o c k w i s e , f i r m l y p r e s s i n g

a g a i n s t t h e s k u l l . R o t a t i o n c o n t i n u e s for % o f a t u r n ,

u n t i l t h e g a p b e t w e e n t h e w r e n c h h a n d l e a n d g u i d e

c y l i n d e r i s c l o s e d .

T h e h a l f t a p i s r e m o v e d f r o m t h e s k u l l , t h e n

l o o s e n e d a n d r e m o v e d f r o m t h e u n i v e r s a l w r e n c h .

T h e full t a p i s n o w t i g h t e n e d t o t h e u n i v e r s a l w r e n c h ,

s l id t h r o u g h t h e g u i d e c y l i n d e r , a n d p l a c e d o v e r t h e

c e n t e r o f t h e s c r e w h o l e . F i r s t , i t i s g e n t l y t u r n e d '/2-

t u r n c o u n t e r c l o c k w i s e ( in o r d e r n o t t o a l t e r t h e t h r e a d

p r e v i o u s l y m a d e b y t h e h a l f t a p ) * « n d t h e n c l o c k w i s e

u n t i l t h e g a p b e t w e e n t h e w r e n c h h a n d l e a n d g u i d e

c y l i n d e r i s c l o s e d . T h e full t a p i s t h e n r e m o v e d f r o m

t h e s c r e w h o l e . T h e t h r e a d i n t h e c e n t e r h o l e i s n o w

r e a d y fo r t h e s c r e w o f t h e i m p l a n t .

T h e full t a p i s r e m o v e d f r o m t h e u n i v e r s a l w r e n c h

h a n d l e a n d r e p l a c e d w i t h t h e s p a n n e r a t t a c h m e n t ,

w h i c h i s d e s i g n e d t o h o l d t h e i m p l a n t b o t h m e c h a n ­

i ca l ly a n d e l e c t r o m a g n e t i c a l l y . T h e i m p l a n t i s p l a c e d

i n t h e s p a n n e r a n d i n s e r t e d t h r o u g h t h e g u i d e c y l ­

i n d e r u n t i l i t f a c e s t h e c e n t e r h o l e ( F i g . 1 5 ^ 3 4 ) . T h e

i m p l a n t ( w i t h t h e s c r e w f a c i n g t h e h o l e ) i s g e n t l y

t u r n e d ' / i - t u r n c o u n t e r c l o c k w i s e ( a g a i n , i n o r d e r n o t

t o a l t e r t h e t h r e a d i n t h e h o l e ) , a n d t h e n c l o c k w i s e

un t i l t h e g a p b e t w e e n t h e w r e n c h h a n d l e a n d g u i d e

c y l i n d e r i s c l o s e d a n d t h e r e i s a f e e l i n g o f r e s i s t a n c e

( F i g . 1 5 - 3 B ) . T h e w r e n c h a n d t h e g u i d e c y l i n d e r a r e

r e m o v e d . T h e i m p l a n t i s g e n t l y c h e c k e d fo r t i g h t n e s s

( F i g . 1 5 - 3 C ) . T h e f l ap i s r e p o s i t i o n e d , t h e i n c i s i o n i s

c l o s e d i n l a y e r s w i t h a p p r o p r i a t e s u t u r e s , a n d a

m a s t o i d d r e s s i n g i s a p p l i e d .

T e s t i n g a n d u s e o f t h e e x t e r n a l d e v i c e b e g i n s a t 8

t o 1 2 w e e k s , d e p e n d i n g u p o n t h e h e a l i n g p r o c e s s .

Complications

T h i s i s a s i m p l e p r o c e d u r e i n t e r m s o f s u r g i c a l

t r a u m a ; i t c a n b e d o n e u n d e r l o c a l a n e s t h e s i a a n d

h a s f e w c o m p l i c a t i o n s . O t h e r t h a n t h o s e i n h e r e n t i n

r a i s i n g a p o s t a u r i c u l a r f l ap ( d i s c u s s e d e l s e w h e r e ) ,

t h e m a i n p o t e n t i a l p r o b l e m i s t h a t o f c e r e b r o s p i n a l

f lu id l e a k . B u r s w i t h a " s t o p " ( s u c h a s t h o s e i n t h e

ki t ) d o n o t a l l o w a d e e p p e n e t r a t i o n ; i f a l e a k d o e s

o c c u r , s e a l i n g ; t h e o p e n i n g w i t h b o n e w a x s h o u l d

s u f f i c e . P r o p h y l a c t i c a n t i b i o t i c s c o u l d b e u s e f u l i n

t h e s e c a s e s . A n in i t i a l h i g h d o s e o f i n t r a o p e r a t i v e

i n t r a v e n o u s a n t i b i o t i c s i s r e c o m m e n d e d . O t h e r c o m ­

p l i c a t i o n s a r e c a u s e d b y f a i l u r e t o f o l l o w c a r e f u l

s u r g i c a l t e c h n i q u e s .

CHAPTER 16

Surgical Approaches for Cochlear Implants i:

A l t h o u g h t h e r e a r e m a r k e d d i f f e r e n c e s a m o n g t h e

d i f f e r e n t t y p e s o f c o c h l e a r i m p l a n t s , t h e b a s i c p r i n ­

c i p l e s o f a n d s u r g i c a l a p p r o a c h e s for t h e s e d e v i c e s

a r e s i m i l a r . T h i s c h a p t e r w i l l d e s c r i b e o n l y t h e b a s i c

s u r g i c a l a p p r o a c h e s t h a t a p p l y t o i m p l a n t s i n w i d e ­

s p r e a d u s e .

C o c h l e a r i m p l a n t s c o n s i s t o f a n e x t e r n a l a n d a n

i n t e r n a l c o m p o n e n t . E x t e r n a l l y , a m i c r o p h o n e p i c k s

u p t h e s o u n d s t i m u l a t i o n a n d s e n d s i t t o t h e s o u n d

p r o c e s s o r , t r a n s f o r m i n g i t i n t o a c o d e d e l e c t r i c a l

s t i m u l u s t h a t i s c a r r i e d t o t h e i n t e r n a l c o m p o n e n t .

A n i n t e r n a l r e c e i v e r c h a n n e l s t h i s s t i m u l u s t h r o u g h

o n e o r m o r e a c t i v e e l e c t r o d e s t o t h e c o c h l e a , for t h e

p u r p o s e o f s t i m u l a t i n g t h e a u d i t o r y n e r v e . A n " i n ­

d i f f e r e n t " o r g r o u n d e l e c t r o d e i s p l a c e d c l o s e t o o r

a w a y f r o m t h e a c t i v e e l e c t r o d e ; i f t h e l a t t e r , i t i s

u s u a l l y p l a c e d i n t h e t e m p o r a l m u s c l e . D i f f e r e n t

t y p e s o f i m p l a n t d e v i c e s r e q u i r e d i f f e r e n t t y p e s o f

g r o u n d e l e c t r o d e s .

T h e i n t e r n a l r e c e i v e r c a n b e p l a c e d e i t h e r u n d e r

t h e s k i n ( t r a n s c u t a n e o u s s t i m u l a t i o n ) o r w i t h a p l u g

p r o t r u d i n g f r o m t h e s k i n ( p e r c u t a n e o u s s t i m u l a t i o n ) .

I n m o s t c a s e s , t h e a c t i v e e l e c t r o d e i s p l a c e d o n o r

t h r o u g h t h e r o u n d w i n d o w o f t h e c o c h l e a . T w o

s u r g i c a l a p p r o a c h e s fo r p l a c e m e n t o f t h e e l e c t r o d e

wi l l b e d e s c r i b e d .

T h r e e b a s i c a p p r o a c h e s c a n b e u s e d : ( 1 ) t h e p o s ­

t e r i o r t y m p a n o t o m y ( fac ia l r e c e s s ) ; ( 2 ) t h e m a s t o i -

d o t o m y / t y m p a n o t o m y ; a n d ( 3 ) t h e e x t e r n a l a u d i t o r y

' c a n a l g r o o v e . T h e a p p r o a c h v i a t h e e x t e r n a l a u d i t o r y

i c a n a l g r o o v e h a s b e e n u s e d for s o m e o f t h e S t o r z -

I S a n F r a n c i s c o d e v i c e s ; i t wi l l n o t b e d e s c r i b e d i n

d e t a i l . A s i n t h e f ac i a l r e c e s s a p p r o a c h , a l a r f e

p o s t a u r i c u l a r f l ap i s e l e v a t e d i n c o n t i n u i t y w i t h t L e

s k i n o f t h e p o s t e r i o r c a n a l a n d t y m p a n i c membrar?I d i r e c t l y e x p o s i n g t h e m i d d l e e a r c a v i t y . A g r o o v e , s

c r e a t e d i n t h e p o s t e r i o r c a n a l , e x t e n d i n g f r o m tte

r e g i o n o f t h e r o u n d w i n d o w t o t h e a n t e r i o r m a r g i i

o f t h e m a s t o i d c o r t e x . T h e g r o o v e i s c o v e r e d w i t h

c o r t i c a l b o n e a n d t e m p o r a l f a s c i a o r w i t h a c r y l i c b o n e

c e m e n t , i n o r d e r t o p r e v e n t s k i n f r o m d i p p i n g i n t o

t h e g r o o v e a n d c o n t a c t i n g t h e e l e c t r o d e l e a d . S u r g i c ? 1

p r e p a r a t i o n a n d p o s i t i o n i n g i s s i m i l a r t o t h a t f l r

m a s t o i d e c t o m y , e x c e p t t h a t t h e a r e a t o b e s h a v í l

a n d p r e p a r e d i s m o r e e x t e n s i v e t h a n i n a r e g u ' r

m a s t o i d e c t o m y . A n i m p o r t a n t p o i n t c o n c e r n s t h e e » *

o f c a u t e r y . W h e n t h e e l e c t r o d e s a r e i n t h e s u r g i ' i i l

f i e l d , t h e u s e o f c a u t e r y m i g h t l e a d t o t h e t r a n s m i ­

s i ó n o f e l e c t r i c a l c u r r e n t s i n t o t h e c o c h l e a , w i l t

p o t e n t i a l l y d e v a s t a t i n g e f f e c t s . J u d i c i o u s u s e o f r i -

p o l a r c a u t e r y , o r n o c a u t e r y a t a l l , i s i n d i c a t e d o n i ;

t h e e l e c t r o d e s a r e i n t h e s u r g i c a l f i e ld .

Posterior Tympanotomy (Facial Recess)

Surgical Steps

1 . P o s i t i o n i n g o f t h e i n t e r n a l r e c e i v e r s i t e .

2 . P o s t a u r i c u l a r i n c i s i o n .

3 . E l e v a t i o n o f a p o s t a u r i c u l a r f l a p .

S u r g i c a l A p p r o a c h e s fo r C o c h l e a r I m p l a n t s 2 8 7

4 . R e m o v a l o f t e m p o r a l m u s c l e .

5 . D r i l l i n g o f a s e a t for t h e i n t e r n a l r e c e i v e r .

6 . S i m p l e m a s t o i d e c t o m y .

7 . O p e n i n g o f t h e fac ia l r e c e s s .

8 . E x p o s u r e o f t h e r o u n d w i n d o w .

9 . P l a c e m e n t o f t h e i n t e r n a l r e c e i v e r .

1 0 . I n s e r t i o n o f t h e e l e c t r o d e v i a t h e r o u n d w i n ­

d o w o p e n i n g .

1 1 . S e c u r i n g o f t h e i n t e r n a l r e c e i v e r .

1 2 . C l o s u r e , p a c k i n g , a n d a m a s t o i d d r e s s i n g .

Procedure

A d u m m y e l e c t r o d e i s u s e d t o d e t e r m i n e t h e

p o s t a u r i c u l a r p o s i t i o n o f t h e i n t e r n a l r e c e i v e r . I t

s h o u l d b e a t o r a b o v e t h e l i n e a t e m p o r a l i s , a l l o w i n g

e n o u g h s p a c e w i t h o u t i n t e r f e r i n g w i t h t h e u s e o f

e y e g l a s s e s . S o m e s u r g e o n s p r e f e r t o p l a c e t h e r e ­

c e i v e r m o r e i n f e r i o r l y . T h e r e c e i v e r s i t e c a n b e t r a c e d

w i t h a m a r k i n g p e n o r a c i r c u l a r i m p r e s s i o n c a n b e

left b y p r e s s i n g a d u m m y r e c e i v e r a g a i n s t t h e s k i n .

I n f i l t r a t i o n o f t h e p o s t a u r i c u l a r i n c i s i o n s i t e i s t h e

s a m e a s i n a m a s t o i d e c t o m y ; h o w e v e r , i t i s m o r e

e x t e n s i v e b e c a u s e o f t h e p o s t e r i o r e x t e n t o f t h e i n c i ­

s i o n . T h e i n c i s i o n i s m a d e 1 c m b e h i n d t h e o u t e r

e d g e o f t h e i n t e r n a l r e c e i v e r a n d e x t e n d s d o w n t o

t h e l e v e l o f t h e m a s t o i d p r o c e s s w i t h o u t b e n d i n g

t o w a r d it , i n o r d e r t o a v o i d c o m p r o m i s e o f t h e

o c c i p i t a l a r t e r y . T h e f l ap i s d e v e l o p e d a n t e r i o r l y

b e t w e e n t h e s c a l p a n d t h e t e m p o r a l m u s c l e u n t i l t h e

s p i n e o f H e n l e i s e x p o s e d .

A p i e c e o f t e m p o r a l m u s c l e o v e r t h e s q u a m o u s

p o r t i o n o f t h e t e m p o r a l b o n e i s r e m o v e d , a s w e l l a s

t e m p o r a l f a s c i a . T h i s a l l o w s for a n a d e q u a t e s e a t for

t h e r e c e i v e r , a n d for a t h i n n e r s c a l p i f a t r a n s c u t a ­

n e o u s d e v i c e i s t o b e u s e d . A s e a t for*1 t h e i n t e r n a l

r e c e i v e r i s d r i l l e d ( F i g . 1 6 — I B ) . I t i s i m p o r t a n t t o d o

t h i s i n a p l a n e p a r a l l e l t o t h e s c a l p s u r f a c e . W i t h a

t r a n s c u t a n e o u s d e v i c e , i t i s u s e f u l t o s e c u r e t h e

r e c e i v e r w i t h p e r m a n e n t s u t u r e s ( F i g . 1 6 - 2 A , 8 ) .

W i t h a 2 - m m p i l o t d r i l l , t w o h o l e s 2 m m a p a r t a r e

d r i l l e d o n b o t h s i d e s o f t h e s e a t , a t a d i s t a n c e o f 0 . 5

t o 0 . 7 5 c m f r o m t h e o u t e r e d g e ; a p a s s a g e b e t w e e n

t h e h o l e s i s m a d e w i t h a 0 . 5 - m m c u t t i n g b u r a t a 3 0 -

d e g r e e a n g l e . F o r a p e r c u t a n e o u s d e v i c e , a d d i t i o n a l

h o l e s c a n b e d r i l l e d fo r p l a c e m e n t o f s c r e w s ( F i g . 1 6 -

2 / V ) .

A s i m p l e m a s t o i d e c t o m y a n d o p e n i n g o f t h e fac ia l

r e c e s s i s d o n e ( F i g . 1 6 - 1 A ) ( s e e C h a p t e r 7 ) ; t h e o n l y

d i f f e r e n c e i s t h a t t h e e d g e s o f t h e c a v i t y a r e n o t

s a u c e r i z e d i n o r d e r t o a l l o w for a g r o o v e fo r t h e

e l e c t r o d e . T w o a d d i t i o n a l h o l e s c a n b e d r i l l e d i n t h e

b o r d e r o f t h e m a s t o i d c a v i t y for t h e p u r p o s e o f

s e c u r i n g t h e e l e c t r o d e a t t h i s l e v e l w i t h p e r m a n e n t

s u t u r e s .

T h e r o u n d w i n d o w n i c h e i s v i s u a l i z e d t h r o u g h

t h e fac ia l r e c e s s ( F i g . 1 6 - 2 D ) . U s i n g a s m a l l b u r , t h e

a n t e r o s u p e r i o r l ip o f t h e n i c h e i s r e m o v e d a n d t h e

r o u n d w i n d o w m e m b r a n e i s b r o u g h t d i r e c t l y i n t o

v i e w . I f t h e w i n d o w c a n n o t b e v i s u a l i z e d , d r i l l i n g

t o w a r d t h e p r o m o n t o r y w i l l h e l p t o p r o v i d e a s t r a i g h t

v i e w o f t h e b a s a l t u r n , b y p a s s i n g t h e " h o o k . " T h i s

s h o u l d b e d o n e c a u t i o u s l y , i n a s t e p - b y - s t e p f a s h i o n .

I f b o n e g r o w t h i s p r e s e n t i n t h i s a r e a , a " s t r a i g h t

p o s i t i o n " i s r e a c h e d a n d d r i l l i n g i s d o n e a n t e r i o r l y

( f o r w a r d ) i n t o t h e s c a l a t y m p a n i . T h i s w i l l l e a d t o a n

o p e n s c a l a o r p r o v i d e a s p a c e for p l a c i n g t h e e l e c ­

t r o d e .

T h e e l e c t r o d e i s t h e n i n t r o d u c e d a n d t h e r o u n d

w i n d o w n i c h e i s s e a l e d w i t h f a s c i a ( F i g . 1 6 - 3 ) . A

n o n s e r r a t e d o r s p e c i a l l y c o a t e d a l l i g a t o r f o r c e p s

s h o u l d b e u s e d fo r e l e c t r o d e i n s e r t i o n , h e l p e d b y

b l u n t w i r e g u i d e s o r h o e s . E x t r e m e c a r e m u s t b e

u s e d w h e n h a n d l i n g t h e e l e c t r o d e i n o r d e r t o a v o i d

d a m a g i n g it. W i t h t h e 3 M H o u s e t y p e , o n l y t h e

n o n i n s u l a t e d p o r t i o n i s i n t r o d u c e d .

O n c e t h e e l e c t r o d e h a s b e e n p l a c e d , t h e i n t e r n a l

r e c e i v e r i s s e c u r e d . F o r a t r a n s c u t a n e o u s d e v i c e , 4 - 0

s i lk s u t u r e s a r e p a s s e d t h r o u g h t h e 2 - m m h o l e s

d r i l l e d a r o u n d t h e s e a t ( F i g . 1 6 - 4 / 1 ) . F o r a p e r c u t a ­

n e o u s p l u g , a n o p e n i n g i s c r e a t e d j u s t a b o v e t h e

p l u g , a v o i d i n g s k i n t e n s i o n a t all c o s t s . T h e o p e n i n g

i s m a d e w i t h a s k i n p u n c h o f t h e s a m e s i z e a s t h e

p l u g p r o v i d e d i n t h e m a n u f a c t u r e r ' s s u r g i c a l k i t .

T h e p o s t a u r i c u l a r i n c i s i o n i s c l o s e d w i t h 3 - 0 a b ­

s o r b a b l e s u t u r e s for t h e s u b c u t a n e o u s t i s s u e s a n d 4 -

0 s i lk f o r t h e s k i n . A P e n r o s e d r a i n c a n b e u s e d . T h i s

i s f o l l o w e d b y a p p l i c a t i o n o f a m a s t o i d d r e s s i n g .

Mastoidotomy/Tympanotomy Approach

i

Advantages

1 . T e c h n i c a l s i m p l i c i t y .

2 . I n v o l v e s l e s s b o n e d r i l l i n g a n d t i s s u e r e m o v a l .

3 . C a r r i e s a l m o s t n o r i s k t o t h e fac ia l n e r v e .

4 . A l l o w ; fo r d i r e c t v i e w o f a n d w o r k i n t h e r o u n d

w i n d o w n i c h e s .

5 . A c t i v e e l e c t r o d e i s c o v e r e d b y a t h i c k l a y e r o f

t i s s u e a l o n g i t s e n t i r e c o u r s e ( n o t j u s t s u b c u t a n e -

o u s l y ) .

6 . P r o v i d e s a b e t t e r a n g l e i n t h e b a s a l t u r n o f t h e

c o c h l e a for s l i d i n g t h e e l e c t r o d e , m a k i n g full i n s e r t i o n

e a s i e r .

289Surgical Approaches for Cochlear Implants

Round window niche

FIGURE 16-2

Internal receiver seat

B

Surgical Approaches for Cochlear Implants

FIGURE 16-1.

288

S u r g i c a l A p p r o a c h e s fo r C o c h l e a r I m p l a n t s

FIGURE 1 6 - 3

S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s 2 9 1

Internal receiver

1

FIGURE l(M

292 S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s

7 . S m a l l p o s t a u r i c u l a r f l ap c a r r i e s l e s s r i s k o f h e ­

m a t o m a o r i n f e c t i o n ; r e q u i r e s n o d r a i n s ; m a k e s h e a l ­

i n g e a s i e r ; a n d a l l o w s n o t e n s i o n o f t h e s k i n w i t h

p e r c u t a n e o u s p l u g s .

8 . A l l o w s f a s t e r r e c o v e r y a n d s h o r t e r h o s p i t a l i z a ­

t i o n

Surgical Steps

1 . E n d a u r a l i n c i s i o n s ( L e m p e r t 1 a n d I I ) .

2 . C a n a l i n c i s i o n s a t 6 a n d 2 o ' c l o c k .

3 . E x p o s u r e o f t h e m i d d l e e a r .

4 . . D r i l l i n g o f t h e r o u n d w i n d o w n i c h e a n d v i s -

a l i z a t i o n o f t h e r o u n d w i n d o w m e m b r a n e .

5 . S m a l l a t t i c o t o m y .

6 . M a s t o i d o t o m y .

7 . P o s t a u r i c u l a r i n c i s i o n .

8 . R e m o v a l o f t e m p o r a l m u s c l e a n d p e r i o s t e u m

9 . D r i l l i n g o f a s e a t for t h e i n t e r n a l r e c e i v e r .

1 0 . T u n n e l i n g o f t h e e l e c t r o d e f r o m t h e p o s t a u r i c ­

u l a r i n c i s i o n i n t o t h e m a s t o i d o t o m y o p e n i n g

1 1 . I n t r o d u c t i o n o f t h e e l e c t r o d e i n t o t h e a n t r u m

a n d m i d d l e e a r

1 2 . I n s e r t i o n o f t h e e l e c t r o d e i n t o t h e c o c h l e a .

1 3 . S e c u r i n g o f t h e i n t e r n a l r e c e i v e r .

1 4 . C r e a t i o n o f a s k i n o p e n i n g ( fo r p e r c u t a n e o u s

r e c e i v e r s ) .

1 5 . C l o s u r e , p a c k i n g , a n d a m a s t o i d d r e s s i n g .

Procedure

T h e first i n c i s i o n ( L e m p e r t I ) i s m a d e s e m i c i r c u m -

f e r e n t i a l l y b e t w e e n 6 a n d 1 2 o ' c l o c k o n t h e p o s t e r i o r

w a l l a t t h e b o n y c a r t i l a g i n o u s j u n c t i o n . T h e s e c o n d

i n c i s i o n ( L e m p e r t I I ) r u n s b e t w e e n t h e t r a g u s a n d

h e l i x (a t t h e i n c i s u r a ) . T h e e x t e n s i o n o f t h i s i n c i s i o n

i s a p p r o x i m a t e l y 0 . 7 5 c m . T h e p o s t e r i o r c a n a l s k i n

( c a r t i l a g i n o u s p o r t i o n ) i s p r e s e r v e d a n d g e n t l y e l e ­

v a t e d w i t h a s m a l l p e r i o s t e a l e l e v a t o r , c l e a r l y e x p o s ­

i n g t h e e n t i r e p o s t e r i o r b o n y c a n a l ( F i g . 1 6 - 5 / 1 ) . T w o -

p r o n g r e t r a c t o r s a r e u s e d for e x p o s u r e ; o c c a s i o n a l l y

t h r e e - p r o n g r e t r a c t o r s a r e n e e d e d .

W i t h a s c a l p e l , v e r t i c a l i n c i s i o n s a r e m a d e a t 6 a n d

2 o ' c l o c k . In a c o m p l e t e l y d r y f i e ld , a f lap is e l e v a t e d

a n d t h e m i d d l e e a r c a v i t y i s e n t e r e d b e n e a t h t h e

a n n u l u s . Al l a n a t o m i c s t r u c t u r e s a n d l a n d m a r k s a r e

v i s u a l i z e d . U s i n g s t a p e s c u r e t s , t h e p o s t e r i o r c a n a l

w a l l i s e n l a r g e d a n d a s m a l l a t t i c o t o m y i s d o n e ( F i g .

1 6 - 5 8 ) . S p e c i a l a t t e n t i o n i s p a i d t o t h e r o u n d w i n d o w

n i c h e . T h e a n t e r o s u p e r i o r p o r t i o n i s r e m o v e d w i t h a

s m a l l b u r a n d t h e r o u n d w i n d o w m e m b r a n e i s

b r o u g h t d i r e c t l y i n t o v i e w ( F i g . 1 6 - 5 C ) . A n y a d d i ­

t i o n a l d r i l l i n g n e e d e d for e x p o s u r e i s d e l a y e d un t i l

t h e e l e c t r o d e i s i n s e r t e d ( s e e P o s t e r i o r T y m p a n o t o m y

[ F a c i a l R e c e s s ] A p p r o a c h ) .

A p i e c e o f G e l f o a m i s u s e d t o c o v e r t h e r o u n d

w i n d o w a n d a l a r g e p i e c e o f c o t t o n i s p l a c e d o v e r

t h e e a r c a n a l . T h i s a v o i d s c o n t a m i n a t i o n b y b o n e

d u s t a n d d e b r i s f r o m t h e m a s t o i d o t o m y d r i l l i n g .

A m a s t o i d o t o m y i s d o n e b y d r i l l i n g i n t h e fossa

m a s t o i d e a t o w a r d t h e a n t r u m ( F i g . 1 6 - 5 D ) . T h e

o p e n i n g s h o u l d b e l a r g e e n o u g h t o v i s u a l i z e t h e

a n t r u m . T h e p o s t e r i o r e d g e i s b e v e l e d a n d all s h a r p

b o n y e d g e s a r e s m o o t h e d . T h e i n c u s i s d i s a r t i c u l a t e d

f rom i ts s t a p e s a n d m a l l e u s a t t a c h m e n t s w i t h a j o i n t

k n i f e a n d t o t a l l y r e m o v e d . I f d e s i r e d , a d u m m y

e l e c t r o d e c a n b e i n s e r t e d t h r o u g h t h e m a s t o i d o t o m y

o p e n i n g a n d i n t o t h e n i c h e t o v e r i f y t h e a d e q u a c y o f

t h e e x p o s u r e . T h e m i d d l e e a r a n d m a s t o i d a r e t h e n

f i l led w i t h a n a n t i b i o t i c s o l u t i o n .

A p o s t a u r i c u l a r i n c i s i o n i s n e e d e d for t h e s o l e

p u r p o s e o f p l a c i n g t h e i n t e r n a l r e c e i v e r ; i t s h o u l d b e

m a d e a t o r a b o v e t h e l i n e a t e m p o r a l i s , a l l o w i n g

e n o u g h s p a c e w i t h o u t i n t e r f e r i n g w i t h t h e u s e o f

e y e g l a s s e s . L i d o c a i n e ( X y l o c a i n e ) 2 % w i t h 1 : 1 0 0 , 0 0 0

e p i n e p h r i n e i s i n j e c t e d . T h e c i r c u m f e r e n t i a l i n c i s i o n

m e a s u r e s 3 t o 3 . 5 c m a n d i s d e e p e n e d t h r o u g h the

s u b c u t a n e o u s t i s s u e s u n t i l t h e t e m p o r a l m u s c l e i s

r e a c h e d ( F i g . 1 6 - 5 E , F). T h e s e a t s i z e for t h e i n t e r n a l

r e c e i v e r i s m e a s u r e d , a n d t h e c o r r e s p o n d i n g u n d e r ­

l y i n g t e m p o r a l m u s c l e a n d p e r i o s t e u m a r e r e m o v e d .

T h e p e r i o s t e u m i s s a v e d for g r a f t i n g t h e r o u n d w i n ­

d o w n i c h e . T h e b o n e s e a t i s d r i l l e d d o w n t o a c c o m ­

m o d a t e t h e r e c e i v e r ( F i g . 1 6 - 6 / 1 ) a n d , d e p e n d i n g

u p o n t h e t y p e o f r e c e i v e r , a d d i t i o n a l I w 4 e s a r e d r i l l e d

e i t h e r for s u t u r e s o r for s c r e w p l a c e m e n t ( s e e P o s t e ­

r io r T y m p a n o t o m y [ F a c i a l R e c e s s ] A p p r o a c h ) .

A n e l e c t r o d e g u i d e i s p a s s e d f r o m t h e e n d a u r a l t o

t h e p o s t a u r i c u l a r i n c i s i o n b v t u n n e l i n g i t b e n e a t h t h e

t e m p o r a l m u s c l e . A n e l e c t r o d e g u i d e , w h i c h i s s i m ­

i lar t o a n a n t r u m t r o c a r , i s s p e c i a l l y c u r v e d a n d h a s

a b l u n t d i s t a l o p e n i n g t o a v o i d d a m a g i n g t h e e l e c ­

t r o d e ( F i g . 1 6 - 6 8 ) . T h e o b t u r a t o r i s r e m o v e d a n d the

e l e c t r o d e i n t r o d u c e d i n t o t h e g u i d e ( F i g . 1 6 - 6 C ) ; t he

g u i d e i s t h e n w i t h d r a w n a n d , w i t h it , t h e e l e c t r o d e

i s c a r r i e d i n t o t h e m a s t o i d o t o m y o p e n i n g . I t i s t h e n

p a s s e d t o t h e a n t r u m a n d i n t o t h e m i d d l e e a r . T h e

e x p o s e d r o u n d w i n d o w m e m b r a n e i s d e t a c h e d w i t h

a n a n g l e d p i c k , a n d t h e e l e c t r o d e i s i n t r o d u c e d w i t h

a n o n s e r r a t e d b a b y a l l i g a t o r f o r c e p s i n a n a n g l e

p o i n t i n g t o w a r d t h e b a s a l t u r n o f t h e c o c h l e a , i m ­

m e d i a t e l y p a s t t h e h o o k ( F i g . 1 6 - 6 D ) . T h e o p e n i n g

o f t h e r o u n d w i n d o w i s s e a l e d w i t h p e r i o s t e u m

w r a p p e d a r o u n d t h e e l e c t r o d e ( F i g . 1 6 - 7 A ) . S m a l l

p i e c e s o f C e l f o a m a r e t h e n p l a c e d l a t e r a l t o t h e

S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s 293

FIGURE 16-5

Ground electrode

Surglcal Approaches for Cochlear Implants 295

A

FIGURE 1&--7

Surgical Approaches for Cochlear Implants294

2 9 6 S u r g i c a l A p p r o a c h e s for C o c h l e a r I m p l a n t s

p e r i o s t e u m g r a f t . W i t h a S y m b i o n i m p l a n t , t h e p r o ­

m o n t o r y e l e c t r o d e i s p o s i t i o n e d o v e r t h e p r o m o n t o r y

a n d s e c u r e d w i t h a c o v e r i n g o f p e r i o s t e u m g ra f t a s

w e l l .

T h e i n t e r n a l r e c e i v e r i s t h e n s e c u r e d i n p l a c e w i t h

s u t u r e s o r s c r e w s ( F i g . 1 6 - 7 B ) , t h e g r o u n d e l e c t r o d e

( i f s e p a r a t e ) i s p l a c e d i n t h e t e m p o r a l m u s c l e f i be r s ,

a n d t h e r e s t o f t h e p e r i o s t e u m i s u s e d t o seal , t h e

a n t r u m . I f a p e r c u t a n e o u s p l u g i s b e i n g u s e d , im­

p e d a n c e i s c h e c k e d a t t h i s p o i n t . A n o p e n i n g for t h e

p l u g i s m a d e a n t e r i o r t o t h e p e r i a u r i c u l a r i n c i s i o n

w i t h a s k i n p u n c h o f t h e s a m e s i z e a s t h e p l u g (F ig .

1 6 - 7 C ) . S k i n t e n s i o n s h o u l d b e a v o i d e d .

T h e c a n a l f lap i s r e p o s i t i o n e d . G e l f o a m a n d a n

a n t i b i o t i c o i n t m e n t a r e u s e d i n t h e d i s t a l t w o t h i r d s

o f t h e c a n a l , a n d g a u z e i s e m b e d d e d i n a n t i b i o t i c

o i n t m e n t i n t h e d i s t a l o n e t h i r d . I n c i s i o n s a r e c l o s e d

w i t h s u b c u t a n e o u s 3 - 0 c h r o m i c c a t g u t a n d s k i n s u ­

t u r e s o f 4 - 0 s i l k ( F i g . 1 6 - 7 D ) , a n d a m a s t o i d d r e s s i n g

i s a p p l i e d .

CHAPTER 17

Surgery for ; Incapacitating Peripheral Vertigo

T h e t i t l e o f t h i s c h a p t e r h a s b e e n p u r p o s e l y s e ­

l ec ted t o i n d i c a t e t h a t t h e s u r g i c a l p r o c e d u r e s d e ­

s c r i b e d h e r e a r e d e s i g n e d for t r e a t m e n t o f v e r t i g o o f

l a b y r i n t h i n e o r i g i n . A t t h e s a m e t i m e , t h e t e r m " i n ­

c a p a c i t a t i n g " i m p l i e s t h a t s y m p t o m s a r e s t i l l p r e s e n t

after a d e q u a t e m e d i c a l e v a l u a t i o n a n d t r e a t m e n t . I t

i s u n d e r s t o o d , t h e r e f o r e , t h a t t h e s e p r o c e d u r e s a r e

p e r f o r m e d i n a s m a l l p e r c e n t a g e o f p a t i e n t s , s i n c e i n

t he m a j o r i t y o f c a s e s m e d i c a l t r e a t m e n t a l o n e wi l l

su f f i ce . ( E v a l u a t i o n a n d m e d i c a l t r e a t m e n t a r e o u t ­

s ide t h e s c o p e o f t h i s b o o k . ) I n a d d i t i o n , i t s h o u l d

be k e p t i n m i n d t h a t v e r t i g o i s a m a n i f e s t a t i o n o f an

u n d e r l y i n g p r o b l e m t h a t m u s t b e a s s e s s e d a n d ( i f

p o s s i b l e ) d e f i n e d ; d e p e n d i n g o n t h e c a u s e , d i f f e r e n t

su rg ica l a l t e r n a t i v e s wi l l b e s e l e c t e d . T h i s i s o n e o f

the a r e a s i n o t o l o g y w h e r e o u r l a c k o f t r u e k n o w l e d g e

i s m o s t e v i d e n t ; t h e r e f o r e , c a r e f u l a n d n o n d e s t r u c t i v e

c h o i c e s a r e r e c o m m e n d e d i f a t all p o s s i b l e .

S u r g i c a l p r o c e d u r e s c a n b e d e s t r u c t i v e o r c o n s e r ­

va t ive i n n a t u r e . T h e y m a y b e a i m e d a t d r a i n i n g a n

a s s u m e d e n d o l y m p h a t i c h y d r o p s , w h e t h e r a t t h e

e n d o l y m p h a t i c s a c l e v e l o r a t t h e s a c c u l e , t h e y m a y

i n v o l v e d e s t r u c t i o n o f t h e l a b y r i n t h ( l a b y r i n t h e c -

t o m y ) a n d / o r s e c t i o n i n g o f t h e v e s t i b u l a r n e r v e o r

o t h e r n e r v e s , s u c h a s t h e s i n g u l a r n e r v e o f t h e

p o s t e r i o r s e m i c i r c u l a r c a n a l . N o n e o f t h e m a n y s u r ­

gical p r o c e d u r e s a v a i l a b l e a r e u n i v e r s a l l y a c c e p t e d o r

p r o v i d e 1009c r e l i e f . T h e s e a r e f a c t o r s t o k e e p i n

m i n d w h e n s e l e c t i n g a s p e c i f i c a p p r o a c h . T h i s c h a p ­

ter wil l d e s c r i b e t h o s e t h a t a r e u s e d o r d i s c u s s e d

m o s t c o m m o n l y , w i t h o u t i m p l y i n g t h a t t h o s e n o t

d e s c r i b e d a r e u s e l e s s o r u n i m p o r t a n t .

Endolymphatic Sac Procedures

T h e s e p r o c e d u r e s c o n s t i t u t e a c o n s e r v a t i v e , u s u ­

a l l y e f f i c i e n t a p p r o a c h for v e r t i g o , a n d a r e t h e in i t ia l

c h o i c e ( n o t u n c o m m o n l y t h e o n l y c h o i c e n e c e s s a r y )

o f m a n y s u r g e o n s . D e s p i t e t h e l o c a t i o n o f t h e s a c i n

t h e p o s t e r i o r f o s s a d u r a , k n o w l e d g e o f i t s a n a t o m y

a n d a d e q u a t e s u r g i c a l t e c h n i q u e u s u a l l y p e r m i t a

s a f e o p e r a t i o n . I n t h e e v e n t o f f a i l u r e , a n y o t h e r

p r o c e d u r e c a n b e d o n e w i t h o u t a d d e d d i f f i c u l t y

Aim

T o i d e n t i f y a n d e x p o s e t h e e n d o l y m p h a t i c s a c

o v e r l y i n g t h e d u r a m a t e r o f t h e p o s t e r i o r c r a n i a l

f o s s a .

Highlights and Surgical Steps

1 . P e r f o r m a c o m p l e t e s i m p l e m a s t o i d e c t o m y .

2 . Dr i l l t o , b u t n o t b e l o w , t h e d o m e o f t h e h o r i ­

z o n t a l s e m i c i r c u l a r c a n a l .

3 . I d e n t i f y , p r e s e r v e , a n d m e a s u r e t h e h a r d a n g l e

c o n t a i n i n g t h e p o s t e r i o r s e m i c i r c u l a r c a n a l .

4 . I d e n t i f y t h e p o s i t i o n o f t h e s i g m o i d s i n u s a n d

its r e l a t i o n s h i p t o T r a u t m a n n ' s t r i a n g l e .

298 S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

I . D e c o m p r e s s t h e l a t e r a l s i n u s a n d d i s s e c t t h e

i n f r a l a b y r i n l h i n e ce l l t r ac t .

6 . I n c i s e t h e e n d o l y m p h a t i c s a c .

Pitfalls

1 . S k e l e t o n i z i n g o r d a m a g i n g t h e p o s t e r i o r s e m i ­

c i r c u l a r c a n a l .

2 . I n s u f f i c i e n t l y u n r o o f i n g t h e d u r a l p l a t e .

3 . F a i l i n g t o i d e n t i f y t h e e n d o l y m p h a t i c s a c a n d

i t s l u m e n .

4 . D a m a g i n g t h e i n c u s .

5 . D e b r i s i n t h e m i d d l e e a r .

6 . B l e e d i n g i n t h e l a t e r a l s i n u s ,

Procedure

I n e n d o l y m p h a t i c s a c s u r g e r y , a t h o r o u g h s i m p l e

m a s t o i d e c t o m y ( s e e C h a p t e r 7 ) i s a d v o c a t e d . D u r i n g

t h i s s t e p t h e b o n y p l a t e o v e r l y i n g t h e p o s t e r i o r c r a ­

nia l f o s s a d u r a i s i d e n t i f i e d . T r a u t m a n n ' s t r i a n g l e i s

d e f i n e d a n d t h e h a r d b o n e c o n t a i n i n g t h e p o s l e r i o r

s e m i c i r c u l a r c a n a ! i s i d e n t i f i e d ( F i g . \7-\A. H). T h e

s a c c o m e s t o w a r d t h e d u r a f r o m t h e d i r e c t i o n o f ( h e

p o s t e r i o r s e m i c i r c u l a r c a n a l a n d c a n b e i d e n t i f i e d a s

i t e x i t s ( h e h a r d a n g l e i n t a c t . A g o o d m e t h o d o f

p r e v e n t i n g d a m a g e t o t h e p o s t e r i o r s e m i c i r c u l a r c a n a l

i s t o m e a s u r e t h e a r e a c o n t a i n i n g t h i s s t r u c t u r e ,uul

l e a v e i t u n t o u c h e d ( u n d r i l l e d ) . W i t h a l e n e s t r o n i e t e r ,

m e a s u r e H I m m f r o m t h e t ip o f t h e s h o r t p r o c e s s o t

t h e i n c u s o r f o s s a i n c u d i s , a l o n g [ h e a \ i s o l [ h e

h o r i z o n t a l s e m i c i r c u l a r c a n a l ( 3 0 d e g r e e s f rom t h e

l e g m e n ) ; t h e n m e a s u r e 1 2 m m f rom I h e loss . i i m u d i s

a t a n a n g l e o t I S d e g r e e s k o n i t h e l e g m e n l l i g . 1 7

\H). T h i s are . i i s lett u n t o u c h e d w h i l e ( h e i n l r a l . i l n -

r i n t h i n e ce l l t r ac t i s d r i l l e d I n e x p o s e t h e s a c l o c a t i o n

( F i g . \7-\H. C ) . S p e c i a l a t t e n t i o n i s p a i d to t h e

p o s i t i o n o f ( l i e s i g m o i d s i n u s ( F i g . 1 7 - 2 / 1 ) ; o n o c c a ­

s i o n , i t p a r t i a l l y o v e r l i e s ( h e d u r a l p l a t e , r e d u c i n g

t h e s i z e o f T r a u t m a n n ' s t r i a n g l e ( i n t e r e s t i n g l y , t h i s

i s fa i r ly c o m m o n i n p a t i e n t s w i t h M e n i e r e ' s d i s e a s e ) .

T h e p l a t e i s t h i n n e d d o w n t o e g g s h e l l t h i c k n e s s ,

t h e n g e n t l y e l e v a t e d a n d s e p a r a t e d f r o m t h e u n d e r ­

l y i n g d u r a w i t h a d u c k b i l l e l e v a t o r . T h e s a c i s i d e n ­

t i f i a b l e a s a t h i c k e n e d w h i t e a r e a o f t h e d u r a ewer

t h e t h in s u r r o u n d i n g d u r a ( F i g . I 7 - 2 R ) . T h e p o s t e r i o r

s e m i c i r c u l a r c a n a l s h o u l d n o t b e t h i n n e d o r s k e l e t o n ­

i z e d . D r i l l i n g i s d o n e i m m e d i a t e l y i n f e r i o r t o th is

a r e a . I f t h e l a t e ra l s i n u s is in s u c h a p o s i t i o n tha t i t

t e n d s t o p a r t i a l l y c o v e r t h e d u r a o r m a k e a c c e s s t o i t

d i f f i cu l t , t h e p a t i e n t ' s p o s i t i o n s h o u l d b e c h e c k e d

first ; t h e h e a d m i g h t b e b e n t t o o far f o r w a r d . I f a f t e r

r e p o s i t i o n i n g t h e h e a d o f t h e p a t i e n t t h e s i n u s i s s t i l l

p r o m i n e n t , i t s h o u l d b e d e c o m p r e s s e d b y r e m o v i n g

p a r t o f i t s b o n y c o v e r i n g l a c i n g t h e d u r a , i n f r a l a b y ­

r i n t h i n e c e l l s m a y h a v e t o b e d r i l l e d ( l e a d i n g t o w a r d ,

t h e j u g u l a r b u l b ) . T h e s a c i s i d e n t i f i e d .

A t t h i s p o i n t , t h e r e a r e s e v e r a l a l t e r n a t i v e s :

1 . D e c o m p r e s s i o n o f t h e s a c ( r e m o v a l o f t h e b o n y

c o v e r i n g ) i s all t h a t i s d o n e .

2 . T h e s a c i s i n c i s e d in its l a t e r a l s u r f a c e w i t h a

s h a r p k n i f e ( f o r e x a m p l e , a s i c k l e k n i f e ) . T h i s i s t h e

o r i g i n a l ( a n d c u r r e n t ) P o r t m a n n p r o c e d u r e ( F i g . 17-

2 C ) .

3 . A v a l v e i s p l a c e d in t h e l u m e n (in t h e e x p e c t a ­

t i o n t h a t m i c r o l i t e r s o f e x c e s s i v e e n d o l y m p h w i F

d r a i n ) .

4 . A s m a l l i n c i s i o n i s m a d e o n t h e m e d i a l s u r f a c e

o f t h e s a c i n o r d e r t o o p e n u p t h e s u b a r a c h n o i d

s p a c e . I n t o t h i s o p e n i n g a f l a n g e d T e f l o n t u b e i s

i n s e r t e d . The o u t e r s u r f a c e i s t i g h t l y p a c k e d ( a p i e c e

o f f a sc i a c a n b e u s e d ) .

5 . A t h in p i e c e o f S i l a s t i c s h e e t i n g ( 0 . 0 1 c m ) i s c u t

i n a T - s h a p e d f a s h i o n a n d p l a c e d i n t h e l u m e n . S m a l l

p i e c e s o f S i l a s t i c s h e e t i n g ( s p a c e r s ) a r e u s e d t o s e p ­

a r a t e t h e d u r a f r o m t h e f l o o r o f t h e p o s t e r i o r c a n a l .

A S i l a s t i c " a p r o n " i s a p p l i e d a n d h e l d i n p l a c e w i t h

C - e l f o a m ( F i g . 1 7 - 3 / 1 - D ) .

1 l ie m a s t o i d c a v i t y i s p a c k e d w i t h G e l t o a m o v e i

t h e d e c o m p r e s s e d a r e a , and t h e inc is ion i s c l o s e d i n

lavers w i t h a p p r o p r i a t e Mitures. A t t h e end o f t h e

p r o c e d u r e , a v e n t i l a t i o n tube m a \ ho p l a c e d in t h e

t v m p a n i c m e m b r a n e ( F i g . I 7 - - 3 / V 1 1 i s i m p o r t a n t t o

t h o r o u g h l y c leanse the m a s t o i d c a \ 1 ' he I ore c l o s u r e .

I h e e f f e c t i v e n e s s o f t h i s p r o c e d u r e m a v h e d u e t o

d e c o m p r e s s i o n o l o v e i l v i n g h o n e , d r a i n a g e o f e n

d o l v m p h b v o p e n i n g o l I h e sac, i n c r e a s e d v a s c u l a r ­

i ty , or o t h e r lac lors , , i d i s i uss ion i s o u t s i d e the s c o p e

n l t h i s b o o k . I h e l a d r e m a i n s t h a t a n v p r o c e d u r e '

tha t i n v o h e s o p e n i n g t h e s a c h a s c o m p a r a b l e r e s u l t s .

C o m p l i c a t i o n s a r e t h o s e o f m a s t o i d e c t o m y ( s e e

C h a p t e r 7 ) , o p e n i n g o f t h e p o s t e r i o r s e m i c i r c u l a r

c a n a l , a n d c e r e b r o s p i n a l f luid f i s t u l a e . T h e b e s t t r e a t - '

m e r i t i s p r e v e n t i o n . T h e t e c h n i q u e o f i s o l a t i n g t h e

h a r d a n g l e i s p r a c t i c a l . I f t h e p o s t e r i o r s e m i c i r c u l a r

c a n a l i s a c c i d e n t a l l y o p e n e d , t h e f i s tu la s h o u l d b e

g r a f t e d i m m e d i a t e l y ; h o w e v e r , a " d e a d e a r " i s a l m o s t

c e r t a i n . F i s t u l a e t h a t l e a k c e r e b r o s p i n a l f lu id a r e

u n c o m m o n a n d s e l f - l i m i t i n g ; h i g h - d o s e a n t i b i o t i c s

s h o u l d b e u s e d i n o r d e r t o a v o i d m e n i n g i t i s . I t i s

u n c o m m o n t o h a v e t o r e - e x p l o r e a n d p l a c e a l a r g e

p i e c e o f f a sc i a a n d m u s c l e ( a l o n g w i t h t i g h t p a c k i n g

o f t h e m a s t o i d e a v i t v w i t h C e l f o a m ) .

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

FIGURE 17-1

300 Surgery for Inc~pacitaling Peripheral Ver";;nSurgery for Incapacitating Peripheral Vertigo 301

T-strut IOserted

0.01 ern Silastic

Apron

E

IICUgl: 17-2.

HCUgE 17-}

3 0 2 S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

Saccule Procedures

T h e s e a r e m e n t i o n e d for t h e s a k e o f c o m p l e t e n e s s

a n d a n o v e r a l l c o n c e p t . T h e m o s t c o m m o n ( s u c h a s

t h e F i c k a n d t a c k p r o c e d u r e s ) a r e a s s o c i a t e d w i t h

s e v e r e , i r r e v e r s i b l e s e n s o r i n e u r a l h e a r i n g l o s s a n d

a r e r a r e l y u s e d . ( A n i n t e r m e d i a t e , s a f e r a l t e r n a t i v e

u s e d o c c a s i o n a l l y i n c a s e s o f o t o s c l e r o s i s a s s o c i a t e d

f l f c i t h h y d r o p s i s a w i r e c o n n e c t i v e t i s s u e p r o s t h e s i s

w i t h a s m a l l p e g [ f r o m t h e w i r e a r o u n d t h e c o n n e c ­

t i v e t i s s u e ] [ F i g . 1 7 - 4 4 ) ; t h i s i s d e s c r i b e d i n C h a p t e r

1 3 . ) B o t h p r o c e d u r e s a r e i n t e n d e d t o d e c o m p r e s s a

d i l a t e d s a c c u l e u n d e r t h e a n t e r i o r p o r t i o n o f t h e o v a l

w i n d o w , w h i c h i s c l e a r l y e x p o s e d . T h e v a r e d o n e

t h r o u g h a t r a n s c a n a l a p p r o a c h . T h e F i c k o p e r a t i o n

i n v o l v e s o p e n i n g t h e f o o t p l a t e a n d t h e n t h e s a c c u l e

( F i g . 1 7 - 4 C ) , w h e r e a s t h e t a c k p r o c e d u r e i n v o l v e s

t h e p l a c e m e n t o f a s h a r p t a c k t h r o u g h t h e f o o t p l a t e

( a n t e r i o r a s p e c t ) ( F i g . 1 7 - 4 8 ) . I t i s i m p o r t a n t t o sea l

t h e f o o t p l a t e w i t h c o n n e c t i v e t i s s u e . T h e t a c k " d e -

I c o m p r e s s e s " t h e s a c c u l e w h e n i t b e c o m e s d i l a t e d .

C l o s u r e i s s i m i l a r t o t h a t for a s t a p e d e c t o m y .

Singular Neurectomy

1 h i s s e l e c t i v e l y d e s t r u c t i v e p r o c e d u r e e n t a i l s s e c ­

t i o n i n g t h e n e r v e o f t h e p o s t e r i o r s e m i c i r c u l a r c a n a l

( . s ingu la r n e r v e ) for t h e t r e a t m e n t o f b e n i g n p e r i p h -

e r a l p o s i t i o n a l v e r t i g o ( c a u s e d b y a n a l t e r a t i o n i n t he

f f l p s t e r i o r s e m i c i r c u l a r c a n a l , s u c h a s c u p u l o l i t h i a s i s ) .

T h e n e r v e r u n s p a r a l l e l t o t h e a n t e r o s u p e r i o r p o r t i o n

o f t h e r o u n d w i n d o w m e m b r a n e ( F i g . 1 7 - 5 / 1 ) .

f t T h e r o u n d w i n d o w n i c h e i s e x p o s e d via a t r a n s -

c a n a l a p p r o a c h . I f n e c e s s a r y , ( h e p o s t e r o i n f e r i o r

c a n a l w a l l i s c u r e t t e d for b e t t e r e x p o s u r e . T h e b o n v

r o u n d w i n d o w n i c h e i s d r i l l e d c a r e f u l l y w i t h a s m a l l

b u r a n d t h e a n t e r o s u p e r i o r p o r t i o n o f t h e r o u n d

w i n d o w m e m b r a n e i s e x p o s e d ( F i g . 1 7 - 5 H ) . T h e b o n e

H t m c d i a t e l y a n t e r i o r t o t h e m e m b r a n e i s t h i n n e d

d o w n ( w i t h o u t i n v o l v i n g t h e m e m b r a n e a n d l e a v i n g

a p i e c e o f b o n e i n t a c t b e t w e e n t h e m e m b r a n e a n d

t h e t h i n n e d a r e a ) . T h e n e r v e i s 1.5 t o 2 m m d e e p

( s l i g h t l y d e e p e r i s t h e b a s a l t u r n o f t h e c o c h l e a ) ; i t i s

• r e n t i f i e d a n d s e c t i o n e d w i t h a n a n g l e d h o o k (F ig .

p — 5 C ) , a n d t h e a r e a i s c o v e r e d w i t h G e l f o a m .

I T h i s p r o c e d u r e i s m o r e e a s i l y d e s c r i b e d t h a n per ­

f o r m e d . I t i s q u i t e d i f f i cu l t t o f ind t h e n e r v e { e v e n i n

a t e m p o r a l b o n e i n t h e l a b o r a t o r y ) . F o r a n y b o d y

a t t e m p t i n g t h i s p r o c e d u r e , a r e a s o n a b l e n u m b e r o f

t e m p o r a l b o n e d i s s e c t i o n s a r e r e c o m m e n d e d .

D e s t r u c t i o n o f t h e p o s t e r i o r l a b y r i n t h b y u l t r a ­

s o u n d ( A r s l a n ' s p r o c e d u r e ) i s n o t d e s c r i b e d i n t h i s

b o o k . I t s i n d i c a t i o n s a r e f e w a n d c a n b e c o v e r e d b y

the o t h e r p r o c e d u r e s ; f u r t h e r m o r e , t h e a u t h o r h a s

n o e x p e r i e n c e w i t h it. T h e r e a d e r i s r e f e r r e d t o t h e

l i t e r a t u r e .

Labyrinthectomy

L a b y r i n t h e c t o m y , a p r o c e d u r e t h a t i s fa i r ly c o m ­

m o n l y e m p l o y e d , e n t a i l s to ta l d e s t r u c t i o n o f t h e

l a b y r i n t h . I t s h o u l d b e r e s e r v e d for p a t i e n t s w i t h n o

u s a b l e h e a r i n g ; e v e n t h e n , t h e s i g n i f i c a n c e o f t h e

p r o c e d u r e m u s t b e c o n s i d e r e d . I s t h e c a u s a t i v e d i s ­

e a s e b i l a t e r a l ? C o u l d i t e v e n t u a l l y b e c o m e b i l a t e r a l ?

I s t h e r e a n y c h a n c e t h a t t h e p a t i e n t n e e d s a c o c h l e a r

i m p l a n t ?

A l a b y r i n t h e c t o m y c a n b e d o n e t h r o u g h a t r a n s -

c a n a l o r a t r a n s m a s t o i d a p p r o a c h .

Transcanal Approach

H i g h l i g h t s

1 . C l e a r i d e n t i f i c a t i o n o f t h e fac ia l n e r v e i s e s s e n ­

tial t o a v o i d a n y p o t e n t i a l l e s i o n s h i l e d r i l l i n g i n

t he o v a l w i n d o w .

2 . R e m o v a l o f t h e o v a l w i n d o w c o n t e n t s m u s t b e

d o n e w i t h o u t d e e p e n i n g t h e w i n d o w o r p u s h i n g t h e

i n s t r u m e n t h a r d i n t o t h e w a l l s . O n l y a t h in p l a t e

s e p a r a t e s t h i s a r e a f rom t h e i n t e r n a l a u d i t o r y c a n a l ,

a n d a c e r e b r o s p i n a l f lu id l eak is a p o t e n t i a l c o m p l i ­

c a t i o n .

E x p o s u r e i s o b t a i n e d via a n e x p l o r a t o r y t y m p a n ­

o t o m y a p p r o a c h ( s e e C h a p t e r 5 ) . B o t h t h e o v a l a n d

the r o u n d w i n d o w s a r e e x p o s e d . I t i s i m p o r t a n t t o

v i s u a l i z e a n d i d e n t i f y t h e p o s i t i o n a n d s t a t u s o f t h e

facial n e r v e i n r e l a t i o n s h i p t o t h e o v a l w i n d o w ( F i g .

1 7 - 6 ) . T h e s t a p e s i s r e m o v e d a n d t h e c o n t e n t s o f t h e

ova l w i n d o w a r e s u c t i o n e d . W i t h a h o o k , t h e r e s t o f

t h e c o n t e n t s a r e r e m o v e d ( F i g . 1 7 - 7 / 1 , B). T h e p r o ­

m o n t o r y i s d r i l l e d a n d b o t h w i n d o w s a r e c o n n e c t e d

( F i g . 1 7 - 7 C ) . T h e l a b y r i n t h i s f i l l ed w i t h G e l f o a m

s a t u r a t e d w i t h s t r e p t o m y c i n s u l f a t e .

Text continued on page 3 0 7

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o 303

Incus

FIGURE V-4

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

FIGURE 17-6.

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o 307

Transmastoid Approach (Transmastoid Labyrinthine Dissection)

Aim

C o m p l e t e r e m o v a l o f t h e s e m i c i r c u l a r c a n a l s a n d

the sof t t i s s u e o f t h e v e s t i b u l e

Highlights

1 . T h e s i n o d u r a l a n g l e m u s t b e c o m p l e t e l y

t h i n n e d fo r a d e q u a t e e x p o s u r e o f t h e v e s t i b u l e .

2 . T h e t e g m e n m u s t b e t h i n n e d for a d e q u a t e v i s ­

u a l i z a t i o n o f t h e s u p e r i o r a s p e c t o f t h e s e m i c i r c u l a r

c a n a l s .

A s i m p l e m a s t o i d e c t o m y i s d o n e . T h e t h r e e s e m i ­

c i r cu l a r c a n a l s a r e s k e l e t o n i z e d u n t i l t h e m e m b r a n o u s

l a b y r i n t h i s v i s i b l e t h r o u g h t h e b o n e a s a t h i n b l u e

l ine ( F i g . 1 7 - 8 / 1 ) . T h e r e l a t i o n s h i p o f t h e fac ia l n e r v e

t o t he h o r i z o n t a l s e m i c i r c u l a r c a n a l i s d e f i n e d ( F i g .

1 7 - 8 8 ) . T h e t h r e e c a n a l s a r e d r i l l e d ( o n e b y o n e ) a n d

the i r c o n t e n t s c a r e f u l l y r e m o v e d b y s u c t i o n a n d t h e

use o f h o o k s ( F i g . 1 7 - 8 C ) . T h e s p a c e i s f i l led w i t h

G e l f o a m s a t u r a t e d w i t h s t r e p t o m y c i n s u l f a t e .

Retrolabyrinthine Approach to the Cerebellopontine Angle and Sectioning of the Vestibular Nerve

Aim

E x p o s u r e o f t h e c e r e b e l l o p o n t i n e a n g l e a n d t h e

e i g h t h c r a n i a l n e r v e w i t h p r e s e r v a t i o n o f t h e l a b y ­

r in th .

Highlights

1 . M a n n i t o l m a y b e g i v e n t o a i d s h r i n k a g e o f t h e

c e r e b e l l u m .

2 . T h e a n t e r i o r l imi t o f t h e d i s s e c t i o n i s t h e p o s ­

te r io r s e m i c i r c u l a r c a n a l .

3 . T h e s i g m o i d s i n u s m u s t b e a d e q u a t e l y d e c o m ­

p r e s s e d a n d m o b i l i z e d .

4 . B o n e m u s t b e c o m p l e t e l y r e m o v e d f r o m t h e

s i n o d u r a l a n g l e a n d p o s t e r i o r f o s s a .

5 . A d u r a l f l ap i s h i n g e d a n t e r i o r l y a n d d r a p e d

o v e r t h e p o s t e r i o r s e m i c i r c u l a r c a n a l .

6 . T h e s u p e r i o r h a l f o f t h e e i g h t h n e r v e i s s e c ­

t i o n e d .

Pitfalls

1 . F a i l i n g t o r e m o v e b o n e a d e q u a t e l y u p t o t h e

p o s t e r i o r s e m i c i r c u l a r c a n a l .

2 . I n a d v e r t e n t l y e n t e r i n g t h e l a b y r i n t h .

3 . F a i l i n g t o d e c o m p r e s s t h e s i g m o i d s i n u s a d e ­

q u a t e l y , l e a d i n g t 3 p o o r v i s u a l i z a t i o n .

4 . I n c o m p l e t e l y s e c t i o n i n g t h e v e s t i b u l a r n e r v e .

5 . I n a d v e r t e n t l y s e c t i o n i n g t h e c o c h l e a r n e r v e f i ­

b e r s .

Procedure

F o r t h i s a p p r o a c h , t h e p a t i e n t l i e s s u p i n e . T h e

p r e p a r a t i o n a n d d r a p i n g o f t h e p a t i e n t a r e t h e s a m e

a s for a s t a n d a r d e a r p r o c e d u r e , w i t h t h e e x c e p t i o n

t h a t a l a r g e r a r e a o f t h e h e a d i s s h a v e d . T h e p a t i e n t ' s

h e a d i s p o s i t i o n e d a t t h e foo t o f t h e t a b l e t o a l l o w

t h e s u r g e o n ' s l e g s a m p l e r o o m b e n e a t h t h e t a b l e .

T h e p a t i e n t m u s t b e s e c u r e l y s t r a p p e d t o t h e t a b l e ,

s i n c e f r e q u e n t s i d e - t o - s i d e r o t a t i o n i s n e e d e d . T h e

p a t i e n t ' s left low;er a b d o m e n i s a l s o p r e p a r e d a n d

d r a p e d for h a r v e s t i n g o f a n a b d o m i n a l fat g r a f t .

T h e p o s t a u r i c t i l a r i n c i s i o n i s m a d e a s u s u a l b u t i s

l o c a t e d f u r t h e r p o s t e r i o r l y — 2 to 3 cm (at i t s m o s t

p o s t e r i o r p o s i t i o n ) — t o a l l o w d r i l l i n g p o s t e r i o r t o t he

s i g m o i d s i n u s , t h i s i s e s s e n t i a l for c o m p l e t e d e ­

c o m p r e s s i o n o f t h e s i g m o i d s i n u s , w h i c h p e r m i t s

p r o p e r a n g u l a t i o n a n d v i s u a l i z a t i o n i n t o t h e c e r e b e l ­

l o p o n t i n e a n g l e . T h e i n c i s i o n r u n s i n a s e m i l u n a r

f a s h i o n a n d i s c a r r i e d t h r o u g h t h e p e r i o s t e u m o f t h e

m a s t o i d c o r t e x , a v o i d i n g t h e t e m p o r a l m u s c l e s u p e ­

r i o r l y . T h e p e r i o s t e u m i s t h e n e l e v a t e d a n d t h e e a r

h e l d f o r w a r d w i t h c e r e b e l l a r r e t r a c t o r s . R e t r a c t o r s

p l a c e d in a s u p e r i o r - t o - i n f e r i o r d i r e c t i o n wi l l h o l d t h e

t e m p o r a l m u s c l e o u t o f t h e s u r g i c a l f i e ld .

U s i n g t h e l a r g e s t c u t t i n g b u r a n d s u c t i o n i r r i g a ­

t i o n , d r i l l i n g i s b e g u n . T h e m a s t o i d c o r t e x i s r e m o v e d

a s i n a r o u t i n e m a s t o i d e c t o m y . C a r e i s t a k e n t o

s a u c e r i z e t h e e d g e s a n d t o k e e p t h e l a t e r a l m o s t

o p e n i n g a s w i d e a s p o s s i b l e . R e m o v a l o f b o n e i s

e x t e n d e d b e h i n d t h e s i g m o i d s i n u s for a d i s t a n c e o f

u p t o 1 c m ; t h e b o n e i s t h i n n e d t o e g g s h e l l t h i c k n e s s ,

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

FIGURI-'

S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o 309

a n d f ina l r e m o v a l f r o m t h e s i g m o i d a n d d u r a i s

a c c o m p l i s h e d l a t e r w i t h t h e d i a m o n d b u r . B e a l e r t

for e m i s s a r y v e i n s t h a t r u n f r o m t h e s i g m o i d s i n u s

t o t h e m a s t o i d c o r t e x .

A t t h i s p o i n t t h e o p e r a t i n g m i c r o s c o p e i s b r o u g h t

i n t o t h e f i e l d . T h e m a s t o i d e c t o m y i s c o m p l e t e d a s

d e s c r i b e d i n C h a p t e r s 5 a n d 7 , a n d t h e b a s i c l a n d ­

m a r k s ( t h e h o r i z o n t a l s e m i c i r c u l a r c a n a l , t h e i n c u s ,

a n d t h e c o u r s e o f t h e fac ia l n e r v e ) a r e v i s u a l i z e d .

W i t h t h e s e l a n d m a r k s , a c c u r a t e i d e n t i f i c a t i o n o f t h e

p o s t e r i o r s e m i c i r c u l a r c a n a l c a n b e m a d e . T h i s r e p ­

r e s e n t s t h e a n t e r i o r l i m i t for r e m o v a l o f b o n e a n d

e x p o s u r e i n t o t h e c e r e b e l l o p o n t i n e a n g l e ; i f b o n e

r e m o v a l i s n o t c o m p l e t e u p t o t h e p o s t e r i o r s e m i c i r ­

c u l a r c a n a l , a t r o u b l e s o m e r i d g e o f b o n e wi l l h i n d e r

a d e q u a t e e x p o s u r e t o t h e a n g l e . I n t e r i o r l y t h e d i s s e c ­

t i o n i s c o n t i n u e d i n t o t h e i n f r a l a b y r i n t h i n e a n d r e t r o -

facia l c e l l t r a c t s . B o n e r e m o v a l i s a l s o n e c e s s a r y h e r e

for a d e q u a t e e x p o s u r e o f t h e c e r e b e l l o p o n t i n e a n g l e

a n d t h e e i g h t h c r a n i a l n e r v e . T h e p o s t e r i o r f o s s a

d u r a i s . f o l l o w e d m e d i a l l y a n d t h e j u g u l a r b u l b , i f

s u p e r i o r l y l o c a t e d , i s e x p o s e d . T h e s u p e r i o r l imi t

w i t h i n t h e i n f r a l a b y r i n t h i n e ce l l t r a c t w i l l b e t h e h a r d

b o n e o f t h e l a b y r i n t h . A l t h o u g h i t i s n o t n e c e s s a r y

t o " b l u e - l i n e " it, c o n s t a n t a w a r e n e s s o f t h e l o c a t i o n

o f t h e d e s c e n d i n g p o r t i o n o f t h e fac ia l n e r v e i s

n e e d e d t o a v o i d i n j u r y t o it. T h e e n d o l y m p h a t i c s a c

i s l o c a t e d w i t h i n t h e d u r a a t t h i s l e v e l .

B o n e r e m o v a l f r o m t h e p o s t e r i o r f o s s a d u r a i s n o w

c o m p l e t e d w i t h t h e l a r g e d i a m o n d b u r a n d s u c t i o n

i r r i g a t i o n . T h e d i a m o n d b u r a l l o w s for s a f e r b o n e

r e m o v a l a n d a v o i d s t e a r i n g o f t h e d u r a o r s i n u s .

B i l l ' s i s l a n d o f b o n e i s o f t e n left o v e r t h e s i g m o i d

s i n u s t o p r o t e c t i t d u r i n g r e t r a c t i o n o r f u r t h e r d r i l l i n g

m e d i a l l y

T h e d u r a l o p e n i n g i s m a d e w i t h a N o . 5 9 S B e a v e r

k n i f e o r s i m i l a r s h a r p i n s t r u m e n t . T h e first i n c i s i o n

p a r a l l e l s t h e s i g m o i d s i n u s a n d r u n s b e t w e e n t h e

s i n u s a n d t h e e n d o l y m p h a t i c s a c i n t e r i o r l y ( F i g . 1 7 -

9 / 1 ) . T h e s u p e r i o r i n c i s i o n p a r a l l e l s t h e s u p e r i o r p e ­

t r o s a l s i n u s a n d r u n s i n t h e s i n o d u r a l a n g l e . ( C a r e

m u s t b e t a k e n t o a v o i d i n j u r y t o t h e v e s s e l s a n d t h e

c e r e b e l l u m i m m e d i a t e l y u n d e r t h e d u r a . ) T h e d u r a l

f lap c r e a t e d i s h i n g e d a n t e r o m e d i a l l y a t t h e l e v e l o f

t h e p o s t e r i o r s e m i c i r c u l a r c a n a l ( F i g . 1 7 - 9 8 ) ; i t i s

d r a p e d o v e r t h e c a n a l a n d a s t a y s u t u r e i s p l a c e d i f

n e e d e d . L o n g C o t t o n o i d s a r e p l a c e d o v e r t h e e x ­

p o s e d c e r e b e l l u m ( for p r o t e c t i o n ) a n d g e n t l e r e t r a c ­

t ion i s a p p l i e d . T h e c i s t e r n a l a t e r a l i s i n f e r i o r l y i s

b l u n t l y p r o b e d t o p r o v i d e a p r o f u s e c e r e b r o s p i n a l

f lu id l e a k i f o n e h a s n o t o c c u r r e d ; t h i s a l l o w s t h e

c e r e b e l l u m t o r e l a x . G o o d v i s u a l i z a t i o n o f t h e c e r e ­

b e l l o p o n t i n e a n g l e a n d i t s s t r u c t u r e s i s t h e n o b t a i n e d .

T h e e i g h t h n e r v e l i e s n e a r t h e l e v e l o f t h e a m p u l -

l a t e d e n d o f t h e p o s t e r i o r s e m i c i r c u l a r c a n a l a n d r u n s

in a p l a n e in l i n e w i t h t h e h o r i z o n t a l s e m i c i r c u l a r

c a n a l . W i t h a d e q u a t e e x p o s u r e , t h e fifth n e r v e m a y

b e s e e n a n t e r o s u p e r i o r l y , I n f e r i o r l y t h e n i n t h , t e n t h ,

a n d e l e v e n t h n e r v e s c a n b e s e e n . T h e s e v e n t h n e r v e

l i e s m e d i a l t o t h e e i g h t h a n d c a n b e v i s u a l i z e d w i t h

g e n t l e r e t r a c t i o n o f t he l a t t e r . O f t e n t h e l a t e ra l b r a n c h

o f t h e a n t e r o i n f e r i o r c e r e b e l l a r a r t e r y i s s e e n b e t w e e n

t h e s e v e n t h a n d e i g h t h c r a n i a l n e r v e r o o t l e t s ( F i g .

1 7 - 1 0 / 1 ) . A r a c h n o i d a d h e s i o n s m a y o b s c u r e t h e c e r ­

e b e l l o p o n t i n e a n g l e a n d i ts s t r u c t u r e s . C a r e f u l d i s ­

s e c t i o n w i t h a s h a r p h o o k m a y b e n e e d e d t o l y s e

t h e s e a d h e s i o n s .

A t t h i s l e v e l , t h e e i g h t h n e r v e c o n s i s t s o f o n e

t r u n k . T h e v e s t i b u l a r s e g m e n t o f t h e n e r v e l i e s s u ­

p e r i o r t o t h e c o c h l e a r s e g m e n t . U s u a l l y , c a r e f u l h i g h -

p o w e r i n s p e c t i o n o f t h e n e r v e t r u n k wi l l r e v e a l t h e

c l e a v a g e p l a n e s e p a r a t i n g t h e t w o s e g m e n t s ; i t i s

o f t e n h i g h l i g h t e d b y a s m a l l v e s s e l o n t h e s u r f a c e o f

t h e n e r v e ( F i g . 1 7 - 1 0 8 ) . ( In a p p r o x i m a t e l y 2 0 % o f

p a t i e n t s , t h i s p l a n e i s d i f f i c u l t t o d i s c e r n . ) U s i n g a

s m a l l h o o k , t h e c l e a v a g e p l a n e i s d e v e l o p e d . S e c t i o n ­

i n g o f t h e v e s t i b u l a r d i v i s i o n i s d o n e w i t h a s h a r p

h o o k o r m i c r o s c i s s o r s , c a r e f u l l y a v o i d i n g i n j u r y t o

t h e fac ia l o r c o c h l e a r n e r v e s ( F i g . 1 7 - 1 0 C ) . A s t h e

v e s t i b u l a r d i v i s i o n i s s e c t i o n e d t h e e n d s wi l l r e t r a c t ,

l e a v i n g a 3 - t o 4 - m m g a p .

A f t e r s e c t i o n i n g o f t h e n e r v e , t h e c e r e b e l l o p o n t i n e

a n g l e i s i n s p e c t e d fo r g o o d h e m o s t a s i s . T h e p r e v i ­

o u s l y h a r v e s t e d a b d o m i n a l fat i s cu t i n t o l o n g s t r i p s ,

w h i c h a r e p l a c e d j u s t i n t o t h e d u r a l o p e n i n g w i t h

t h e ta i l s b r o u g h t o u t t o t h e m a s t o i d c a v i t y . C a r e f u l

a n d t i g h t p l a c e m e n t o f t h e s e s t r i p s h a s b e e n f o u n d

t o p r o v i d e a g o o d s ea l a g a i n s t p o s t o p e r a t i v e c e r e b r o ­

s p i n a l f lu id l e a k a g e . The l o n g t a i l s a r e t h e n f o l d e d

i n t o t h e m a s t o i d a n d a n t r u m , a n d t h e p o s t a u r i c u l a r

i n c i s i o n i s c l o s e d . A m a s t o i d p r e s s u r e d r e s s i n g i s

a p p l i e d a n d left i n p l a c e for t w o d a y s .

Intraoperative Complications or Problems

W i t h g o o d t r a i n i n g a n d e x p e r t i s e , t h i s p r o c e d u r e

i s r e m a r k a b l y f ree o f i n t r a o p e r a t i v e c o m p l i c a t i o n s .

T h e m o s t c o m m o n p r o b l e m s a r e c a u s e d b y b l e e d i n g

f r o m i n j u r y t o t h e s i n u s e s ; t h e y a r e t r e a t e d a s d i s ­

c u s s e d i n C h a p t e r 5 ( T r a n s l a b y r i n t h i n e A p p r o a c h t o

t h e I n t e r n a l A u d i t o r y C a n a l ) . W i t h c a r e f u l p r e p a r a ­

t i o n a n d m e t i c u l o u s e x p o s u r e , o t h e r p r o b l e m s l i s t ed

t h e r e s h o u l d b e a v o i d e d . A d d i t i o n a l p o t e n t i a l p r o b ­

l e m s a r e t h o s e a c c o m p a n y i n g a m a s t o i d e c t o m y .

S u r g e r y fo r I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

F1CUKE 17-9

FIGURE 17-10.

3 1 2 S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

Pertinent Histopathology

F I G U R E 1 7 - 1 1

T h i s t e m p o r a l b o n e w a s f r o m a n i n d i v i d u a l w h o

u n d e r w e n t f e n e s t r a t i o n o f t h e h o r i z o n t a l s e m i c i r c u l a r

c a n a l f o r a v e r t i g i n o u s s y n d r o m e . T h e v e r t i g o s u b - |

s i d e d t e m p o r a r i l y . T h i s s e c t i o n s h o w s t h a t w h a t I

a p p e a r t o b e s i m p l e c o n s e r v a t i v e " f e n e s t r a t i o n s "

r e s u l t i n l o c a l i z e d r e a c t i o n s w i t h n e w b o n e f o r m a t i o n . ,

S u r g e r y fo r I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o 313

F I G U R E 1 7 - 1 2

T h i s p a t i e n t u n d e r w e n t a n u n s u c c e s s f u l " r o u n d s h o w s t h e m a r k e d l o c a l i z e d i n f l a m m a t o r y r e a c t i o n i n

w i n d o w l a b y r i n t h o t o m y " for v e r t i g o . A s e v e r e s e n - t h e r o u n d w i n d o w n i c h e t h a t i s a s s o c i a t e d w i t h

s o r i n e u r a l h e a r i n g l o s s t h a t w a s p r e s e n t p r e o p e r a - s e e m i n g l y m i n o r s u r g i c a l t r a u m a ,

l i v e l y d i d n o t c h a n g e p o s t o p e r a t i v e l y . T h i s s e c t i o n

3 1 4 S u r g e r y for I n c a p a c i t a t i n g P e r i p h e r a l V e r t i g o

Middle c a r caviry

I - T C U K F 17-1 .1

"1'liis p a t i e n t u n d e r w e n t .in i i i i s v m r - s l n l l . u k p ro - n o t a c h i e v e i N p u i p o s e , b i l l s u c h l a i l u r c i s i n f r e -

t c c l u r e for .1 v e r t i g i n o u s s v m l r o m c . I he o p e n i n g in q u c n l . I h i - s e i l i o n i s p r e s e n t e d in o r d e r to R i v e a j

t h e f o o t p l a t e c o r r e s p o n d s t o t h e s i t e o f t h e l a c k . 1 h e v i s u a l o r i e n t a t i o n t o e n d o l y m p h a t i c h y d r o p s a n d thej l

s e c t i o n s h o w s t h a t i n s p i t e o f t h e l a c k t h e h y d r o p s r a t i o n a l e for a t a c k p r o c e d u r e ,

p e r s i s t e d (nn-rnes). I n t h i s p a r t i c u l a r c a s e t h e t a c k d i d

CHAPTER 18

Intratemporal Facial Nerve Surgery

T h e a i m o f t h e p r o c e d u r e s d i s c u s s e d i n t h i s c h a p ­

t e r i s t o r e - e s t a b l i s h s a f e c o n t i n u i t y o f t h e a x o n s o f

t h e fac ia l n e r v e t h a t h a v e b e e n c o m p r o m i s e d b y

t r a u m a o r d i s e a s e . T h i s r e m a i n s c o n s t a n t w h e t h e r

t h e p r o c e d u r e i n v o l v e s f r e e i n g , d e c o m p r e s s i n g , o r

r c a n a s t o m o s i n g . A c o m p l e t e d i s c u s s i o n o f t h e i nd i ­

c a t i o n s for s u r g i c a l e x p l o r a t i o n o f t h e fac ia l n e r v e o r

a n y o f i t s s e g m e n t s i s o u t s i d e t h e s c o p e o f t h i s a t l a s ;

t he c o m m e n t s h e r e a t e i n t e n d e d o n l v t o c o n t r i b u t e

t o a t h o r o u g h u n d e r s t a n d i n g o f s p e c i f i c p r o c e d u r e s

I n f r a t e m p o r a l fac ia l n e r v e p a r a l v s i s c a n b e c a u s e d b v

d i f t e r e n t l a c t o r s a n d c a n i n c u r i n d i f f e r e n t s e g m e n t s

b a s e d o n a d e q u a t e p r e o p e r a t i v e a s s e s s m e n t , t h e re ­

q u i r e d p r o c e d u r e m i g h t i n v o l v e a w i d e m v r i n g o t -

o m y , a t r a n s c a n a l o r t r a n s m a s t o i d a p p r o a c h , a n e x ­

p l o r a t i o n o f t h e first n e r v e s e g m e n t a t t h e i n t e r n a l

a u d i t o r y c a n a l , o r a t o t a l fac ia l n e r v e e x p l o r a t i o n .

Myringotomy

F a c i a l p a r a l y s i s m a y o c c u r d u r i n g a n a c u t e e p i s o d e

o f o t i t i s m e d i a . P e r f o r m i n g a w i d e m y r i n g o t o m y for

d r a i n a g e o f p u r u l e n t e f f u s i o n , o b t a i n i n g a s a m p l e for

c u l t u r e , a n d p l a c i n g a l a r g e - b o r e t u b e ( a l o n g w i t h

a d e q u a t e m e d i c a l t r e a t m e n t ) wi l l s u f f i c e i n t h e m a ­

j o r i t y o f c a s e s . I t i s i m p o r t a n t t o u s e a l a r g e t u b e

S m a l l t y p e I t u b e s t e n d t o b e c o m e p l u g g e d , r e q u i r i n g

a s e c o n d d r a i n a g e p r o c e d u r e .

Transmastoid Approach

Surgical Steps

1

2

3

ne rv

<]

T h o s e o f a s i m p l e m a s t o i d e c t o m y

T h o s e o f a fac ia l r e c e s s a p p r o a c h (if n e e d e d )

I d e n t i f y i n g t h e d i f f e r e n t s e g m e n t s o f t h e facial

: a n d s k e l e t o n i z i n g t h e fac ia l c a n a l

R e m o v i n g t h e b o n y c o v e r i n g

O p e n i n g t h e s h e a t h o f t h e n e r v e ( i f i n d i c a t e d ) .

Procedure

F o r p r a c t i c a l s u r g i c a l p u r p o s e s , t h e fac ia l n e r v e

c a n b e d i v i d e d i n t o t h r e e s e g m e n t s : ( 1 ) w i t h i n t h e

i n t e r n a l a u d i t o r y c a n a l a n d l a b y r i n t h ; ( 2 ) t h e m a s t o i d

( v e r t i c a l ) ; a n d ( 3 ) t h e t y m p a n i c ( h o r i z o n t a l m i d d l e

e a r ) .

T h e t r a n s m a s t o i d a p p r o a c h p r o v i d e s a c c e s s t o t he

t y m p a n i c a n d n a s t o i d s e g m e n t s o f t h e n e r v e . S i m p l e

m a s t o i d e c t o m y a n d fac ia l r e c e s s a p p r o a c h e s h a v e

b e e n d e s c r i b e d u p t o t h e p o i n t o f c l e a r l y i d e n t i f y i n g

t h e fac ia l ( f a l l o p i a n ) c a n a l . T h e a n a t o m y o f t h e c a n a l

s h o u l d n o w b e r e a s s e s s e d ( F i g . 1 8 - 1 / 1 ) .

Mastoid Segment. F r o m t h e e v t o — ' p r o c e e d s

3 1 6 I n f r a t e m p o r a l F a c i a l N e r v e S u r g e r y

Cochleariform Eustachian tube process

External genu

FIGURI- 18-1

t h e l e v e l o f t h e a n t e r i o r e d g e o f t h e d i g a s t r i c r i d g e

( F i g . 1 8 - 1 A 8 ) . T h e n e r v e u s u a l l y i s m e d i a l t o t h e

h o r i z o n t a l c a n a l ( a g o o d l a n d m a r k ) , h u t a t t i m e s i t

m a y b e l a t e r a l t o i t ( c o n g e n i t a l l y o r b y i n f l a m m a t o r y

d i s e a s e ) o r i t m a y h a v e a p o s t e r i o r p r o j e c t i o n a t t h e

g e n u , l e n d i n g i t s e l f t o p o t e n t i a l d a m a g e . I t i s u s e f u l

t o v i s u a l i z e t h e n e r v e a n t e r i o r t o t h e d i g a s t r i c r i d g e ,

n o t i n g h o w l a t e r a l i t b e c o m e s a s i t r e a c h e s t h e m a s ­

t o i d t i p .

Tympanic Segment. T h e n e r v e a p p e a r s i n t h e r e g i o n

o f t h e c o c h l e a r i f o r m p r o c e s s a t t h e g e n i c u l a t e g a n ­

g l i o n , t h e n r u n s p o s t e r i o r l y t o w a r d t h e o v a l w i n d o w

( n o t u n c o m m o n l y , i t i s d e h i s c e n t a t t h i s p o i n t ) to a

p o i n t j u s t i n f e r i o r a n d g e n e r a l l y m e d i a l ( d e e p e r ) t o

t h e h o r i z o n t a l s e m i c i r c u l a r c a n a l . E x p o s u r e o f t h e

t y m p a n i c s e g m e n t i s h e l p e d b y e n l a r g i n g t h e a d i t u s

a d a n t r u m . T h i s d i s s e c t i o n , c o m b i n e d w i t h e n l a r g e ­

m e n t o f t h e fac ia l r e c e s s a p p r o a c h , a l l o w s v i s u a l i z a ­

t ion a n t e r i o r l y t o w a r d t h e c o c h l e a r i f o r m p r o c e s s .

D r i l l i n g w i t h a s m a l l b u r i s d o n e u n d e r t h e i n c u s

w i t h o u t d a m a g i n g o r d i s l o c a t i n g it; i f t h i s i s n o t

p o s s i b l e ( w h i c h u s u a l l y i s t h e c a s e ) , t h e i n c u s c a n b e

r e m o v e d w i t h a j o i n t k n i f e ( F i g . 1 8 - 2 / 1 ) . I f n e c e s s a r y ,

t h e t e n d o n o f t h e t e n s o r t y m p a n i c a n b e s e c t i o n e d ,

p e r m i t t i n g e l e v a t i o n o f t h e m a l l e u s ; t h i s wil l a l l o w

c o m p l e t e d r i l l i n g t o w a r d t h e g e n i c u l a t e g a n g l i o n . I f

r e q u i r e d fo r b e t t e r e x p o s u r e , a n e x p l o r a t o r y t y m p a n ­

o t o m y f l ap ( p r e v i o u s l y d e s c r i b e d ) c a n b e e l e v a t e d

a n d a d d i t i o n a l t r a n s c a n a l e x p o s u r e c a n b e o b t a i n e d .

T h e m a s t o i d s e g m e n t c a n b e d i s s e c t e d f r o m t h e l eve l

o f t h e f o s s a i n c u d i s o r f r o m t h e d i g a s t r i c r i d g e . F r o m

t h e r i d g e , i t c a n b e f o l l o w e d s u p e r i o r l y t o t h e e x t e r n a l

g e n u ; a l t h o u g h t h i s a p p r o a c h i s p e r f e c t l y a c c e p t a b l e ,

t h e a u t h o r s t e n d t o f o l l o w n e r v e s p e r i p h e r a l l y r a t h e r

t h a n c e n t r a l l y a n d t o s t a r t a t t h e l e v e l o f t h e f o s s a

i n c u d i s . D r i l l i n g i s d o n e w i t h p a r a l l e l s t r o k e s i n t h e

d i r e c t i o n o f t h e n e r v e ( s u p e r i o r t o i n f e r i o r o r v i c e

v e r s a ) .

T h e e n t i r e fac ia l c a n a l s h o u l d b e t h i n n e d t o e g g ­

s h e l l c o n s i s t e n c y w i t h a d i a m o n d o r p o l i s h i n g b u r .

H o w e v e r , t h e fac ia l n e r v e s h e a t h s h o u l d n o t b e

e x p o s e d w i t h t h e b u r . T h e t h i n n e d b o n e i s f r a c t u r e d

w i t h a p i c k a n d t h e b o n e f r a g m e n t s a r e l i f ted g e n t l y

w i t h a W h i r l y b i r d , w i t h o u t u s i n g t h e fac ia l n e r v e a s

a f u l c r u m ( F i g . 1 8 - 2 8 ) . T h e s h e a t h i s s p l i t o p e n w i t h

a s h a r p s i c k l e k n i f e o r a B e a v e r k n i f e ( F i g . 1 8 - 2 C ) .

S p e c i a l s i t u a t i o n s a n d h a n d l i n g o f t h e n e r v e i t s e l f a r e

d e s c r i b e d b e l o w . W h e n c l o s i n g , t h e i n c u s i s r e p o s i ­

t i o n e d a n d h e l d i n p l a c e b y s e v e r a l s m a l l p i e c e s o f

G e l f o a m . B o t h a r t i c u l a t i o n s ( w i t h t h e s t a p e s a n d t h e

m a l l e u s ) a r e c a r e f u l l y r e p o s i t i o n e d . C l o s u r e a n d

p a c k i n g a r e d o n e a s i n a m a s t o i d p r o c e d u r e . T h e

e x p o s e d n e r v e i s t h e n c o v e r e d w i t h g o l d foil ( o r a

s i m i l a r m a t e r i a l ) i n o r d e r t o a v o i d f i b r o s i s a n d t i s s u e

I n t r a t e m p o r a ) F a c i a l N e r v e S u r g e r y 317

i n g r o w t h . F a s c i a s h o u l d n o t b e u s e d d i r e c t l y o v e r

t h e n e r v e f i b e r s .

Transcanal Approach

T h i s a p p r o a c h a l l o w s a c c e s s t o t h e t y m p a n i c s e g ­

m e n t o f t h e f ac i a l n e r v e a n d , i f e x t e n d e d i n t e r i o r l y ,

m a k e s i t p o s s i b l e t o e x p o s e t h e m a s t o i d s e g m e n t

d o w n t o t h e s t y l o m a s t o i d f o r a m e n . T h i s c a n b e u s e d

a d e q u a t e l y in a s c l e r o t i c m a s t o i d , b u t in a w e l l -

p n e u m a t i z e d m a s t o i d i t m i g h t r e s u l t i n a l a r g e c a v i t y

w i t h a n u n d e r l y i n g e x p o s e d n e r v e . R i s k s o f i n f e c t i o n

i n t h e s e c a s e s m u s t b e c o n s i d e r e d . T h i s e x p o s u r e c a n

a l s o b e o b t a i n e d b y a n e n d a u r a l a p p r o a c h .

Procedure

A l a r g e t y m p a n o m e a t a l f lap i s c r e a t e d w i t h v e r t i c a l

i n c i s i o n s a t 2 a n d 6 o ' c l o c k , a n d t h e m i d d l e e a r c a v i t y

i s e n t e r e d b e n e a t h t h e a n n u l u s ( s e e C h a p t e r 7 ) . T h e

p o s t e r i o r a n d s u p e r i o r w a l l s a r e e n l a r g e d w i t h b u r s

a n d c u r e t s t o f a c i l i t a t e e x p o s u r e . T h e i n c u s i s s e p a ­

r a t e d f r o m t h e s t a p e s w i t h a j o i n t k n i f e . I f n e c e s s a r y ,

t h e t e n d o n o f t h e t e n s o r t y m p a n i i s s e c t i o n e d t o

a l l o w e l e v a t i o n o f t h e m a l l e u s . T h e f a l l o p i a n c a n a l i s

t h i n n e d , t h e s h e a t h i s e x p o s e d , a n d t h e p r o c e d u r e i s

c o n t i n u e d a s i n t h e t r a n s m a s t o i d a p p r o a c h ( i n c l u d i n g

r e p o s i t i o n i n g o f t h e i n c u s ) . T h e f lap i s r e p o s i t i o n e d

a n d t h e c a n a l i s p a c k e d ( F i g . 1 8 - 3 ) .

Special Situations and Manage.nent of the Nerve

T h e t e c h n i q u e s d e s c r i b e d a s s u m e t h e n e e d for

t o t a l d e c o m p r e s s i o n , w h i c h i s n o t n e c e s s a r i l y t h e

c a s e a t all t i m e s . I n c a s e s o f a c u t e m a s t o i d i t i s ( w i t h

a n e x p o s e d n e r v e a n d facia l p a r a l y s i s ) w i t h n o p e n ­

e t r a t i o n o f t h e fac ia l n e r v e s h e a t h b y g r a n u l a t i o n

t i s s u e o r c h o l e s t e a t o m a , i t m i g h t b e b e t t e r n o t t o

o p e n t h e s h e a t h . T h e r e i s a r i s k t h a t t h e n e r v e c a n

b e i n v o l v e d b y t h e u n d e r l y i n g i n f l a m m a t o r y p r o c e s s .

A t h o r o u g h m a s t o i d e c t o m y w i t h a f ac i a l r e c e s s a p ­

p r o a c h , a l l o w i n g c l e a n s i n g a n d a e r a t i o n o f t h e c a v i t y

a n d m i d d l e e a r , m i g h t s u f f i c e . I t i s a l s o p o s s i b l e tha t

o p e n i n g o f t h e s h e a t h , f o l l o w e d b y b u l g i n g o f t h e

n e r v e u n t i l n o r m a l n e r v e a r e a s a r e e x p o s e d a t b o t h

e n d s o f t h e b u l g e , m a y b e s u f f i c i e n t .

318 !nlratemporal Facial Nerve Surgery Intralemporal Facial Nerve Surgery 319

Incus

Gold toil

Exposed nerve

FIGURE 1B-3

\Exposed nerve

Whirlybird

B

Cochleariform process

A

c

3 2 0 i n t r a t e m p o r a l F a c i a l N e r v e S u r g e r y

I n c a s e s o f h e r p e s z o s t e r , i t i s a p p r o p r i a t e t o

d e c o m p r e s s u p t o t h e g e n i c u l a t e g a n g l i o n .

F r a c t u r e s o f t h e t e m p o r a l b o n e i n v o l v i n g t h e facial

n e r v e m a y b e l o n g i t u d i n a l o r t r a n s v e r s e . T r a n s v e r s e

f r a c t u r e s t e n d t o o c c u r a l o n g t h e a x i s o f t h e i n t e r n a l

a u d i t o r y c a n a l a n d r e q u i r e a m i d d l e c r a n i a l f o s s a

a p p r o a c h ( d e s c r i b e d b e l o w ) . L o n g i t u d i n a l f r a c t u r e s

i n v o l v e t h e o s s i c l e s a n d t y m p a n i c s e g m e n t o f t h e

f a c i a l n e r v e . F r a c t u r e s t h r o u g h t h e m a s t o i d b o n e wil l

a f f e c t t h e m a s t o i d s e g m e n t . A l o n g w i t h o s s i c u l o ­

p l a s t y , b o n e f r a g m e n t s i m p i n g i n g o n t h e n e r v e

s h o u l d b e m e t i c u l o u s l y r e m o v e d .

T r a u m a t o t h e n e r v e m a y a l s o b e t h e r e s u l t o f

a c c i d e n t a l i n j u r y b y a b u r o r o t h e r i n s t r u m e n t , a n d

c a n o c c u r a t a n y l e v e l . This h a p p e n s m o r e c o m m o n l y

i n t h e t y m p a n i c s e g m e n t o n t h e f l oo r o f t h e fac ia l

r e c e s s w h i l e t i s s u e i s b e i n g r e m o v e d . S p e c i a l c a r e

s h o u l d b e o b s e r v e d i n c a s e s o f p r e v i o u s s u r g i c a l

t r a u m a , w h i c h m a y b e t h e r e s u l t o f a n i n a d e q u a t e

a p p r o a c h o r a n u n c o m p l e t e d o p e r a t i o n t h a t left re­

s i d u a l d i s e a s e . I n t h e s e c a s e s , i t i s n e c e s s a r y t o

c o m p l e t e t h e o r i g i n a l o p e r a t i o n , r e a s s e s s a n a t o m i c

l a n d m a r k s , a n d t h e n r e p a i r t h e n e r v e d a m a g e .

M a n a g e m e n t o f t h e a f f e c t e d n e r v e i t s e l f i s a i m e d

a t r e - e s t a b l i s h i n g s a f e c o n t i n u i t y o f t h e n e r v e a x o n s ,

e i t h e r t h r o u g h d e c o m p r e s s i o n o r b y r e s t o r i n g c o n t i ­

n u i t y o f d i s r u p t e d n e r v e f i b e r s . I f t h e a r e a o f d i s r u p ­

t i o n i s s m a l l , t h e e d g e s o f t h e f i b e r s s h o u l d b e

s e c t i o n e d s h a r p l y a n d r e p o s i t i o n e d i n a n a t o m i c c o n ­

t i n u i t y . ( H o w e v e r , m a c e r a t e d e d g e s d o n o t r e g e n e r ­

a t e a d e q u a t e l y . ) I f t h e n e r v e h a s b e e n c o m p l e t e l y

t r a n s e c t e d , t h e e d g e s s h o u l d b e s e c t i o n e d s h a r p l y

a n d b o t h e x t r e m e s b r o u g h t t o g e t h e r a n a t o m i c a l l y

S u t u r i n g i s e x t r e m e l y d i f f i c u l t i n t h e s e c a s e s a n d i s

s e l d o m a d e q u a t e ; a d h e s i v e g l u e s e r v e s t h e p u r p o s e

m o r e e f f e c t i v e l y .

I f t h e n e r v e e d g e s c a n n o t b e b r o u g h t t o g e t h e r o r

i f p a r t o f t h e n e r v e m u s t b e r e m o v e d ( a s i n e x c i s i o n

o f a n e u r o m a ) , a n e r v e gra f t i s c a l l e d for . T h i s g ra f t

w i l l s e r v e a s a m a t r i x o r p a t h w a y fo r t h e a x o n s t h a t

a r e g r o w i n g f r o m t h e p r o x i m a l p o r t i o n i n t o t h e d i s t a l

e n d . A l t h o u g h t h e r e a r e m a n y s o u r c e s o f n e r v e

g r a f t s , b r a n c h e s o f t h e s u p e r f i c i a l c e r v i c a l p l e x u s

( e s p e c i a l l y t h e g r e a t e r a u r i c u l a r n e r v e ) a r e p r e f e r r e d

b e c a u s e t h e y a r e f o u n d i n t h e v i c i n i t y o f t h e o p e r a t i v e

f i e l d , t h e y a r e o f a d e q u a t e s i z e , a n d t h e y a r e e a s i l y

o b t a i n e d . T h e g r e a t e r a u r i c u l a r n e r v e t r a v e r s e s la t­

e r a l l y t o t h e s t e r n o c l e i d o m a s t o i d m u s c l e a f t e r e m e r g ­

i n g a r o u n d i t s p o s t e r i o r e d g e a s a s i n g l e n e r v e t r u n k .

A n i n f r a - a u r i c u l a r i n c i s i o n i s d e e p e n e d t h r o u g h

s u b c u t a n e o u s t i s s u e s . A n t e r i o r a n d p o s t e r i o r s k i n

f l a p s a r e d e v e l o p e d , t h e s t e r n o c l e i d o m a s t o i d muscle-

i s e x p o s e d , a n d t h e g r e a t e r a u r i c u l a r n e r v e i s i d e n ­

t i f i ed . T h e n e r v e i s s e c t i o n e d s h a r p l y ( s e l e c t i n g t h e

d e s i r e d l e n g t h ) , a n d t h e w o u n d i s c l o s e d i n l a y e r s

w i t h a p p r o p r i a t e s u t u r e s . T h e s h e a t h s o f t h e t w o

n e r v e s a r e a p p r o x i m a t e d ( p r o x i m a l s t u m p t o p r o x i ­

m a l e n d o f g r e a t e r a u r i c u l a r n e r v e , d i s t a l t o d i s t a l a

w i t h 9 - 0 o r 1 0 - 0 n y l o n s u t u r e s . A d h e s i v e g l u e a l s d 1

c a n b e u s e d .

Middle Cranial Fossa Approach

Aim

T o fu l ly e x p o s e t h e l a b y r i n t h i n e s e g m e n t o f t h e

f ac i a l n e r v e f r o m t h e g e n i c u l a t e g a n g l i o n t o t h e

i n t e r n a l a u d i t o r y c a n a l , a n d t o p r e s e r v e h e a r i n g .

( A l t h o u g h d e s c r i b e d h e r e for fac ia l n e r v e e x p l o r a t i o n ,

t h i s p r o c e d u r e a l s o i s u s e d for r e m o v a l o f s m a l l

i n t r a c a n a l i c u l a r a c o u s t i c n e u r o m a s w h i l e p r e s e r v i n g

g o o d r e s i d u a l h e a r i n g , a n d o c c a s i o n a l l y for s e c t i o n ­

i n g o f t h e v e s t i b u l a r n e r v e . )

Highlights

1 I t a p r i o r fac ia l n e r v e e x p l o r a t i o n t h r o u g h t h e

m a s t o i d a n d t y m p a n i c s e g m e n t s h a s b e e n a c c o m ­

p l i s h e d , a t e g m e n t a l d e f e c t i s m a d e w i t h a d i a m o n d

b u r a t t h e l e v e l o f t h e c o c h l e a r i f o r m p r o c e s s . T h i s

w i l l a i d a c c u r a t e o r i e n t a t i o n w h e n t h e m i d d l e f o s s a

f l o o r i s e x p o s e d .

2 . T h e s u r g e o n i s s e a t e d a t t h e h e a d o f t h e t a b l e

w i t h t h e p a t i e n t s u p i n e .

3 . T h e h o r i z o n t a l l i m b o f t h e c r a n i o t o m y i s t w o -

t h i r d s a n t e r i o r a n d o n e - t h i r d p o s t e r i o r t o t h e e x t e r n a l

a u d i t o r y c a n a l .

4 . T h e a n t e r i o r l i m i t o f d u r a l e l e v a t i o n i s t h e

m i d d l e m e n i n g e a l a r t e r y , w i t h t h e d u r a e l e v a t e d i n

a p o s t c r i o r - t o - a n t e r i o r d i r e c t i o n .

5 . T h e m o s t c o n s i s t e n t l a n d m a r k i s t h e g r e a t e r

s u p e r f i c i a l p e t r o s a l n e r v e ; t h e a r c u a t e e m i n e n c e i s

h e l p f u l b u t i s o f t e n i n d i s t i n c t

6 . M e d i a l t o t h e g e n i c u l a t e , t h e l a b y r i n t h i n e p o r ­

t ion o f t h e f a l l o p i a n c a n a l i s v e r y n a r r o w ; o n l y

m i l l i m e t e r s s e p a r a t e t h e a m p u l l a o f t h e s u p e r i o r

s e m i c i r c u l a r c a n a l p o s t e r i o r l y f r o m t h e c o c h l e a a n t e ­

r i o r ly .

7 . F a m i l i a r i t y w i t h t h e H o u s e - U r b a n r e t r a c t o r i s

r e c o m m e n d e d b e f o r e i ts u s e . I t s m e c h a n i s m a l l o w s

for t h r e e a d j u s t m e n t s d u r i n g r e t r a c t i o n .

I n f r a t e m p o r a l F a c i a l N e r v e S u r g e r y 3 2 1

Pitfalls

1 . T e a r i n g o f t h e d u r a w i t h h e r n i a t i o n a n d d a m a g e

t o t h e t e m p o r a l l o b e .

2 . A v u l s i o n o f t h e g r e a t e r s u p e r f i c i a l p e t r o s a l

n e r v e a n d i n j u r y t o t h e fac ia l n e r v e .

3 . E x c e s s i v e b l e e d i n g f r o m t h e m i d d l e m e n i n g e a l

a r t e r y .

4 . I n j u r y t o t h e c o c h l e a o r s u p e r i o r s e m i c i r c u l a r

c a n a l .

Procedure

F o r t h i s a p p r o a c h t h e p a t i e n t l i e s s u p i n e , a n d t h e

s u r g e o n s i t s a t t h e h e a d o f t h e o p e r a t i n g t a b l e . T h e

i n c i s i o n e x t e n d s s u p e r i o r l y t o t h e a u r i c l e ; t h u s t h e

h e a d s h a v e e x t e n d s n e a r l y t o t h e t o p o f t h e s k u l l

a n t e r i o r l y a n d p o s t e r i o r l y u n t i l v i r t u a l l y t h e e n t i r e

s i d e o f t h e h e a d i s p r e p a r e d for s u r g e r y .

T h e i n c i s i o n i s m a d e a p p r o x i m a t e l y 0 . 5 c m a n t e r i o r

t o t h e t r a g u s a n d e x t e n d s p o s t e r o s u p e r i o r l y for a p ­

p r o x i m a t e l y 6 t o 8 c m ; i t i s c a r r i e d t o t h e l e v e l o f t h e

t e m p o r a l f a s c i a . O f t e n t h e s u p e r f i c i a l t e m p o r a l a r t e r y

i s e n c o u n t e r e d i n f e r i o r l y ; i t i s b e s t to t i e i t w i t h a

s u t u r e . T h i s p l a n e o f d i s s e c t i o n i s d e v e l o p e d b l u n t l y

a n d W e i t l a n e r r e t r a c t o r s a r e p l a c e d . T h e t e m p o r a l

m u s c l e i s i n c i s e d in a T f a s h i o n w i t h t h e h o r i z o n t a l

l i m b e x t e n d i n g a l o n g t h e z y g o m a t i c a r c h for 3 t o 4

c m ; t h e m u s c l e i s t h e n e l e v a t e d f r o m t h e s q u a m o u s

p o r t i o n o f t h e t e m p o r a l b o n e a n d t h e r e t r a c t o r s a r e

r e i n s e r t e d .

A c r a n i o t o m y i s t h e n m a d e by o u t l i n i n g a f lap

a p p r o x i m a t e l y 2 . 5 c m s q u a r e w i t h a l a r g e c u t t i n g b u r

( F i g . 1 8 - 4 / 4 ) . T h e h o r i z o n t a l l i m b s h o u l d b e l o c a t e d

s o t h a t t w o - t h i r d s o f i t l i e s a n t e r i o r t o t h e e x t e r n a l

a u d i t o r y c a n a l , a n d o n e - t h i r d l i e s p o s t e r i o r . T o a v o i d

i n j u r y t o t h e d u r a , t h e c r a n i o t o m y c u t s a r e d r i l l e d t o

p a p e r - t h i n t h i c k n e s s . T h e " b o n e f l a p " i s f r a c t u r e d

w i t h a j o k e r o r s i m i l a r b l u n t i n s t r u m e n t ; i t i s t h e n

c a r e f u l l y e l e v a t e d , a v o i d i n g a n y t e a r i n g o f t h e d u r a ,

w h i c h w o u l d l e a d t o t e m p o r a l l o b e h e r n i a t i o n a n d

p o s s i b l e i n j u r y . F o r o p t i m u m v i s u a l i z a t i o n , t h e f lap

m u s t b e a s c l o s e t o t h e f l o o r o f t h e m i d d l e c r a n i a l

f o s s a a s p o s s i b l e ; t h u s t h e i n f e r i o r c u t i s m a d e a t t h e

l e v e l o f t h e z y g o m a t i c r o o t . I f a l e d g e o f b o n e r e m a i n s

a f t e r t h e f l ap h a s b e e n e l e v a t e d , i t m a y b e r e m o v e d

s h a r p l y w i t h t h e r o n g e u r t o p l a c e t h e o p e n i n g a t t h e

l e v e l o f t h e m i d d l e f o s s a f l oo r . B l e e d i n g m a y o c c u r

f r o m b o n e a n d f rom v e s s e l s o n t h e d u r a l s u r f a c e o f

t h e t e m p o r a l l o b e ; t h e f o r m e r a r e s t o p p e d w i t h b o n e

w a x a n d t h e l a t t e r w i t h l i g h t c a u t e r y . A g a i n , s p e c i a l

c a r e m u s t b e t a k e n t o a v o i d i n j u r i n g t h e d u r a

T h e H o u s e - U r b a n r e t r a c t o r i s t h e n p l a c e d o n t h e

p a r a l l e l v e r t i c a l e d g e s o f t h e c r a n i o t o m y d e f e c t ( F i g .

1 8 - 4 6 ) . T o p r e v e n t t h e d u r a f r o m b e i n g c a u g h t i n

t h e b l a d e s o f t h e r e t r a c t o r , i t i s r e f l e c t e d w i t h a b l u n t

i n s t r u m e n t f r o m t h e e d g e s o f t h e c r a n i o t o m y . T h e

d u r a i s t h e n g e n t l y e l e v a t e d f r o m t h e m i d d l e f o s s a

f l o o r i n a p o s t e r i o r - t o - a n t e r i o r d i r e c t i o n . A s t h e d u r a

a n d t e m p o r a l l o b e a r e e l e v a t e d m e d i a l l y , t h e r e t r a c t o r

b l a d e i s s l o w l y a d v a n c e d t o p r o v i d e t h e n e e d e d

r e t r a c t i o n . T h e f i rs t l a n d m a r k t o b e i d e n t i f i e d i s t h e

m i d d l e m e n i n g e a l a r t e r y a s i t e x i t s f r o m t h e f o r a m e n

s p i n o s u m ( F i g . 1 8 - 4 C ) ; t h i s m a r k s t h e a n t e r i o r l imi t

o f d u r a l e l e v a t i o n . B r i s k b l e e d i n g o f t e n wil l b e e n ­

c o u n t e r e d i n th i s a r e a , n e c e s s i t a t i n g p a c k i n g w i t h

S u r g i c e l . T h e d i s s e c t i o n i s t h e n c o n t i n u e d m e d i a l l y ,

a g a i n i n a p o s t e r i o r - t o - a n t e r i o r d i r e c t i o n . T h e g r e a t e r

s u p e r f i c i a l p e t r o s a l n e r v e i s i d e n t i f i e d ; i t r u n s a n t e ­

r i o r l y o n t h e s u r f a c e o f t h e m i d d l e f o s s a a f t e r e x i t i n g

t h e fac ia l h i a t u s . C a r e f u l p o s t e r i o r - t o - a n t e r i o r d u r a l

e l e v a t i o n wi l l a v o i d i n a d v e r t e n t e l e v a t i o n o f t h i s

n e r v e , w h i c h a u ld p l a c e t r a c t i o n u p o n t h e g e n i c u l a t e

g a n g l i o n a n d M u s e i n j u r y t o it , a s w e l l a s t o t h e

fac ia l n e r v e . I n a s m a l l p e r c e n t a g e o f c a s e s t h e

g e n i c u l a t e g a n g l i o n i t s e l f m a y b e d e h i s c e n t . I f a

d e f e c t h a s b e e n c r e a t e d i n t h e t e g m e n d u r i n g a

p r e v i o u s m a s t o i d e c t o m y , i t i s n o w e n c o u n t e r e d . T h e

s u r g e o n w i l l k n o w t h a t t h e g e n i c u l a t e g a n g l i o n i s

j u s t m e d i a l t o i t .

T h e n e x t l a n d m a r k t o b e i d e n t i f i e d i s t he a r c u a t e

e m i n e n c e , w h i c h m a r k s t h e d o m e o f t h e s u p e r i o r

s e m i c i r c u l a r c a n a l . T h i s i s n o t a c o n s i s t e n t l a n d m a r k

a n d i s f r e q u e n t l y i n d i s t i n c t . I t l i e s s l i g h t l y p o s t e r o ­

m e d i a l t o t h e g e n i c u l a t e g a n g l i o n . A g a i n t h e r e t r a c t o r

b l a d e i s c o n t i n u a l l y a d v a n c e d t o p r o v i d e n e e d e d

r e t r a c t i o n a s t h e d u r a l e l e v a t i o n c o n t i n u e s m e d i a l l y .

I m p o r t a n t s u r f a c e l a n d m a r k s t h a t a i d o r i e n t a t i o n

h a v e n o w b e e n i d e n t i f i e d .

R e m o v a l o f b o n e a n d e x p o s u r e o f t h e fac ia l n e r v e

i s n o w b e g u n . A l a r g e d i a m o n d b u r w i t h s u c t i o n

i r r i g a t i o n ( t o p r e v e n t h e a t t r a n s f e r t o t h e u n d e r l y i n g

fac ia l n e r v e a n d s t r u c t u r e s ) i s u s e d i n i t i a l l y . B o n e

r e m o v a l i s b e g u n a t t h e f ac i a ) h i a t u s a n d c o n t i n u e d

a s h o r t d i s t a n c e p o s t e r i o r l y , f o l l o w i n g t h e g r e a t e r

s u p e r f i c i a l p e t r o s a l n e r v e t o t h e g e n i c u l a t e g a n g l i o n

( F i g . 1 8 - 5 / 1 ) . H e r e t h e fac ia l n e r v e r u n s m e d i a l l y

t o w a r d t h e i n t e r n a l a u d i t o r y m e a t u s . I m m e d i a t e l y

m e d i a l t o t h e g e n i c u l a t e g a n g l i o n , a s m a l l d i a m o n d

b u r i s u s e d , s i n c e o n l y a f e w m i l l i m e t e r s s e p a r a t e t h e

a m p u l l a o f t h e s u p e r i o r s e m i c i r c u l a r c a n a l ( p o s t e r i o r )

f r o m t h e c o c h l e a ( a n t e r i o r ) . T h e fac ia l n e r v e r u n s

t h r o u g h t h i s s m a l l s p a c e . B o n e r e m o v a l i s c o n t i n u e d

m e d i a l l y t o fu l ly e x p o s e t h e l a b y r i n t h i n e s e g m e n t o f

t h e fac ia l n e r v e ; t h i s a f f o r d s m o r e r o o m , s i n c e t h e

p l a n e o f t h e s u p e r i o r s e m i c i r c u l a r c a n a l r u n s i n a 4 5 -

t o 6 0 - d e g r e e a n g l e p o s t e r i o r l y f r o m t h e a m p u l l a .

324 I n f r a t e m p o r a l F a c i a l N e r v e S u r g e r y

B o n e i s t h i n n e d a r o u n d a p p r o x i m a t e l y 5 0 % o f t he

fac ia l n e r v e . T h e e g g s h e l l - t h i n b o n e m a y t h e n b e

r e m o v e d w i t h a h o o k o r b l u n t i n s t r u m e n t . I t i s n o t

n e c e s s a r y t o e x p o s e t h e fac ia l n e r v e a l o n g t h e e n t i r e

l e n g t h o f t h e i n t e r n a l a u d i t o r y c a n a l . M e d i a l d i s s e c ­

t ion t o t h e n a r r o w e s t p o i n t o f t h e c a n a l u s u a l l y

c o n s t i t u t e s a d e q u a t e d e c o m p r e s s i o n . H e r e c e r e b r o ­

s p i n a l f lu id f l o w wil l b e e n c o u n t e r e d u p o n e n t e r i n g

t h e i n t e r n a l a u d i t o r y c a n a l .

T h e fac ia ] n e r v e i s t h e n fn i lv e x p o s e d f rom t h e

g e n i c u l a t e g a n g l i o n d i s t a l l y t o t h e t y m p a n i c s e g m e n t

u p t o t h e c o c h l e a r i f o r m p r o c e s s ( F i g . 1 8 - 5 B ) . ( T h i s i s

e a s i l y p e r f o r m e d t h r o u g h t h e t e g m e n t a l d e f e c t c r e ­

a t e d p r e v i o u s l y . ) C a r e m u s t b e t a k e n n o t t o i n j u r e

t h e m a l l e u s h e a d o r o t h e r o s s i c l e s i n o r d e r t o p r e v e n t

s e n s o r i n e u r a l h e a r i n g l o s s . O p e n i n g t h e fac ia l n e r v e

s h e a t h ( i f d e s i r e d ) m a y b e a c c o m p l i s h e d b y e x t e n d i n g

t h e o p e n i n g f r o m t h e t y m p a n i c s e g m e n t t o t h e

l a b y r i n t h i n e s e g m e n t ( F i g . I 8 - 5 C ) .

T h e d e f e c t i n t h e i n t e r n a l a u d i t o r y c a n a l i s c l o s e s

w i t h a t e m p o r a l m u s c l e p l u g a n d t h e t e m p o r a l l o b £

i s a l l o w e d t o r e - e x p a n d . T h e b o n e f l ap i s t h e n repoV

s i t i o n e d a n d t h e w o u n d i s c l o s e d i n l a y e r s — t e m p o r ; 1

m u s c l e , s u b c u t a n e o u s t i s s u e , a n d s k i n . U s u a l l y n.*

e x t e r n a l d r a i n a g e i s u s e d . A s t e r i l e d r e s s i n g i s ap

p l i e d .

Pertinent Histopathology

F 1 C U K E 1 8 - 6

T h i s p a t i e n t d e v e l o p e d a fac ia l p a r a l y s i s d i a g n o s e s

i n i t i a l l y a s B e l l ' s p a l s y . A n u n s u c c e s s f u l s u r g i c t

d e c o m p r e s s i o n w a s p e r f o r m e d . T h e s e c t i o n show%

t u m o r i n v o l v e m e n t o f t h e fac ia l n e r v e ( m e t a s t a t i c

c a r c i n o m a o f t h e p r o s t a t e ) .

FIGURE 18-6.

CHAPTER 19

Tumors of the Middle and Inner Ear

T u m o r s o f t h e m i d d l e a n d i n n e r e a r i n c l u d e g l o ­

m u s t u m o r s a n d a c o u s t i c n e u r o m a s . G l o m u s t u m o r s ,

o r p r i m a r y v a s c u l a r t u m o r s o f t h e m i d d l e e a r , a r e

c l a s s i f i e d a c c o r d i n g t o t h e i r l o c a t i o n a n d s i z e . G l o m u s

t y m p a n i c u m t u m o r s a r e l i m i t e d t o t h e m i d d l e e a r

a n d m a s t o i d ; g l o m u s j u g u l a r e t u m o r s i n v o l v e t h e

j u g u l a r b u l b , m i d d l e e a r , a n d b a s e o f t h e s k u l l . T h i s

c h a p t e r d e s c r i b e s t h r e e s u r g i c a l a p p r o a c h e s t o g l o ­

m u s t u m o r s b a s e d o n t h e i r s i z e . S m a l l a n d l a r g e

g l o m u s t y m p a n i c u m t u m o r s a r e d i s c u s s e d , a s w e l l

a s g l o m u s j u g u l a r e t u m o r s . T h e c h a p t e r a l s o d e ­

s c r i b e s a t r a n s l a b y r i n t h i n e a p p r o a c h for a c o u s t i c n e u ­

r o m a s

Glomus Tympanicum Tumors

Highlights

1 . A c c u r a t e p r e o p e r a t i v e a s s e s s m e n t o f t h e t u m o r

i s e s s e n t i a l t o e n s u r e t h a t t h e t u m o r i s l i m i t e d t o t h e

m i d d l e e a r o r m a s t o i d .

2 . I f a g l o m u s t u m o r i s l i m i t e d t o t h e p r o m o n t o r y

a n d all o f i t s b o r d e r s c a n b e s e e n b y a t r a n s c a n a l

a p p r o a c h , a n e x p l o r a t o r y t y m p a n o t o m y o r e n d a u r a l

a p p r o a c h m a y b e u s e d .

3 . W h e n t h e e n t i r e c i r c u m f e r e n c e o f t u m o r c a n n o t

b e v i s u a l i z e d b y a t r a n s c a n a l a p p r o a c h a n d p r e o p ­

e r a t i v e a s s e s s m e n t s h o w s n o i n v o l v e m e n t o f t h e

j u g u l a r b u l b , a n e x t e n d e d fac ia l r e c e s s a p p r o a c h i s

u s e d .

Small Glomus Tympan icum Tumors

A n e x p l o r a t o r y t y m p a n o t o m y a p p r o a c h i s u s e d t o

e x p o s e th i s t u m o r , i f all o f i t s b o r d e r s c a n b e v i s u a l ­

i z e d t h r o u g h a t r a n s c a n a l a p p r o a c h ( F i g . 1 9 - 1 / 1 ) . I f

n e e d e d , e n d u r a l i n c i s i o n s a l s o m a y b e u s e d t o a i d i n

e x p o s u r e ( s e e C h a p t e r 7 ) . O f t e n i t i s u s e f u l t o e l e v a t e

t h e t y m p a n i c m e m b r a n e o f f t h e m a l l e u s ( u s i n g a

s h a r p k n i f e o r p i c k ) t o i n c r e a s e e x p o s u r e .

W h e n a d e q u a t e e x p o s u r e i s o b t a i n e d , r e m o v a l o f

t h e t u m o r i s b e g u n . I t i s i m p o r t a n t t o r e a l i z e t h a t

b l e e d i n g m a y b e p r o f u s e a n d n e c e s s i t a t e s w o r k i n g

q u i c k l y a n d e f f e c t i v e l y . T o p i c a l A d r e n a l i n e a n d S u r -

g i ce l o r a s i m i l a r p a c k i n g m a y a l s o b e u s e d d u r i n g

t h e p r o c e d u r e a s n e e d e d . A n i n c i s i o n i s m a d e i n t h e

m u c o u s m e m b r a n e a t t h e p e r i p h e r y o f t h e t u m o r .

T h e t u m o r i s t h e n e l e v a t e d f r o m t h e p r o m o n t o r y ,

m o b i l i z i n g all b o r d e r s ( F i g . 1 9 - 1 8 ) . O c c a s i o n a l l y , a

m a j o r f e e d i n g a r t e r y i s s e e n ; i t m a y b e f u l g u r a t e d

( c a r e m u s t b e t a k e n n o t t o t o u c h t h e p r o m o n t o r y

w i t h t h e c u r r e n t ) . T h e t u m o r i s t h e n r e m o v e d i n t a c t

( F i g . 1 9 - 1 C ) . A g a i n , i f b l e e d i n g i s b r i s k t h e s u r g e o n

m u s t w o r k q u i c k l y ( w i t h l a r g e s u c t i o n a n d p a c k i n g

a s n e e d e d ) t o r e m o v e t h e t u m o r t o t a l l y ; t h e b l e e d i n g

wil l b e e a s y t o c o n t r o l o n c e t h e t u m o r h a s b e e n

r e m o v e d . C l o s u r e a n d p a c k i n g a r e t h e s a m e a s for

t h e s t a n d a r d a p p r o a c h e s

Larger Glomus Tympanicum Tumors

I f t h e e n t i r e b o r d e r o f t h e t u m o r c a n n o t b e v i s u ­

a l i z e d a n d r a d i o l o g i c s t u d i e s s h o w t h a t i t i s l i m i t e d

t o t h e m i d d l e e a r , a p o s t e r i o r a p p r o a c h i s u s e d . T h i s

FIGURI-: I ' M

T u m o r s o f t h e M i d d l e a n d I n n e r E a r 327

a l l o w s v i s u a l i z a t i o n o f t h e s u p e r i o r , p o s t e r i o r , a n d —

m o s t i m p o r t a n t l y , t o e n s u r e t h a t t h e r e i s n o j u g u l a r

b u l b i n v o l v e m e n t — i n f e r i o r b o r d e r s . A t r a n s c a n a l

t y m p a n o t o m y for a n t e r i o r b o r d e r e x p o s u r e m a y b e

u s e d i f t h e r e i s a n y q u e s t i o n o f c a r o t i d a r t e r y i n v o l v e ­

m e n t .

T h e p o s t e r i o r a p p r o a c h i n c l u d e s a p o s t a u r i c u l a r

i n c i s i o n , c o m p l e t e m a s t o i d e c t o m y , a n d o p e n i n g o f

t h e f a c i a l r e c e s s . T h e fac ia l r e c e s s i s t h e n e x t e n d e d

i n t e r i o r l y t o e x p o s e t h e h y p o t y m p a n u m ; t h i s r e q u i r e s

s a c r i f i c i n g t h e c h o r d a t y m p a n i . T h e b o r d e r s o f t h e

e x t e n d e d f ac i a l r e c e s s a r e t h e f i b r o u s a n n u l u s la t ­

e r a l l y a n d t h e f a l l o p i a n c a n a l m e d i a l l y . T h e r e c e s s i s

c a r r i e d i n f e r i o r l y u n t i l i t i s f l u s h w i t h t h e f l o o r o f t h e

m i d d l e e a r . A t t h i s p o i n t , t h e i n f e r i o r b o r d e r o f t h e

t u m o r i s s e e n i n t h e h y p o t y m p a n u m . W i t h a b l u n t

p r o b e , t h e b o n y w a l l o f t h e h y p o t y m p a n u m m a y b e

p a l p a t e d t o e n s u r e b o n e i n t e g r i t y a n d n o n i n v o l v e -

m e n t o f t h e j u g u l a r b u l b . T h e r e t r o f a c i a l a i r c e l l s

s h o u l d a l s o b e o p e n e d s i n c e l a r g e r t u m o r s o f t e n

e x t e n d i n t o t h i s s p a c e ( t h i s a p p r o a c h a l l o w s g o o d

a c c e s s t o t h i s a r e a ) ( F i g . 1 9 - I D ) . S u p e r i o r l y , i f t h e

t u m o r i n v o l v e s t h e o s s i c l e s , t h e i n c u d o s t a p e d i a l j o i n t

m a y n e e d t o b e d i s c o n n e c t e d a n d t h e i n c u s r e m o v e d

t o a l l o w s a f e r e m o v a l o f t h e t u m o r . A n e x p l o r a t o r y

t y m p a n o t o m y m a y b e p e r f o r m e d c o n c u r r e n t l y t o

h e l p e x p o s e a s u p e r i o r l y l o c a t e d t u m o r . A g a i n , e l e ­

v a t i n g t h e t y m p a n i c m e m b r a n e o f f t h e m a l l e u s wi l l

e n h a n c e e x p o s u r e ( a n d a l s o a l l o w d e l i n e a t i o n o f t h e

t u m o r ' s a n t e r i o r b o r d e r ) .

A t t h i s p o i n t , t u m o r r e m o v a l m a y c o m m e n c e .

A g a i n , b r i s k b l e e d i n g n e c e s s i t a t e s r a p i d a n d e f f i c i e n t

w o r k . I f p o s s i b l e , t h e t u m o r i s f r e e d i n i ts e n t i r e t y

a n d r e m o v e d ( F i g . 1 9 — 1 E ) . U s u a l l y t h e t u m o r i s t o o

l a r g e t o p e r m i t t h i s , a n d i t i s r e m o v e d i n p i e c e s a f t e r

f r e e i n g o f i t s p e r i p h e r y . W h e n b r i s k b l e e d i n g i s

e n c o u n t e r e d , t h i s a r e a m a y b e p a c k e d a n d a t t e n t i o n

d i r e c t e d e l s e w h e r e . C a r e m u s t b e t a k e n t o l o o k for

d e h i s c e n c e o r i n v o l v e m e n t o f t h e j u g u l a r b u l b i n f e ­

r i o r l y a n d o f t h e c a r o t i d a r t e r y a n t e r i o r l y .

W h e n c o m p l e t e r e m o v a l i s a c c o m p l i s h e d , o s s i c u l a r

r e c o n s t r u c t i o n i s p e r f o r m e d ( i f n e e d e d ) . T h e i n c i s i o n s

a re c l o s e d i n t h e u s u a l m a n n e r .

Infralabyrinthine, Infratemporal Approach for Glomus Jugulare Tumors

Highlights

1. A c o m p l e t e m a s t o i d e c t o m y ( m a s t o i d t ip re ­

m o v e d ) i s p e r f o r m e d w i t h a n e x t e n d e d f ac i a l r e c e s s

2 . T h e b o n y e x t e r n a l a u d i t o r y c a n a l , t y m p a n i c

m e m b r a n e , i n c u s , a n d m a l l e u s a r e r e m o v e d

3 . T h e fac ia l n e r v e i s m o b i l i z e d a n d t r a n s p o s e d

a n t e r i o r l y .

4 . T h e j u g u l a r v e i n i s i d e n t i f i e d i n t h e n e c k a n d

c o n t r o l l e d i n f e r i o r t o t u m o r .

5 . T h e s i g m o i d s i n u s i s c o n t r o l l e d d i s t a l t o t u m o r .

6 . T h e t u m o r i s r e m o v e d i n a n a n t e r o i n f e r i o r - t o -

s u p e r i o r d i r e c t i o n , w i t h c o n s t a n t a t t e n t i o n g i v e n t o

t h e i n t e r n a l c a r o t i d a r t e r y a n t e r i o r l y .

7 . A s m a l l e r i n t r a c r a n i a l e x t e n s i o n m a y b e h a n ­

d l e d w i t h t h i s a p p r o a c h .

8 . T h e e x t e r n a l a u d i t o r y c a n a l i s s u t u r e d c l o s e d

( c r e a t i n g a b l i n d p o u c h ) ; w i t h a d u r a l d e f e c t , t h e

c a v i t y i s p a c k e d w i t h fat o r m u s c l e .

Pitfalls

1 . I n j u r i n g t h e i n t e r n a l c a r o t i d a r t e r y ( m o s t

c o m m o n l y i n f r a t e m p o r a l l y a t t h e c a r o t i c o t y m p a n i c

b r a n c h ) .

2 . C a u s i n g d e f i c i t s o r i n j u r i e s t o t h e n i n t h , t e n t h ,

e l e v e n t h , a n d t w e l f t h c r a n i a l n e r v e s , w i t h a s s o c i a t e d

p o s t o p e r a t i v e p r o b l e m s .

3 . F a i l i n g t o r e c o g n i z e a s s o c i a t e d l e s i o n s ( s u c h a s

p h e o c h r o m o c y t o m a s , c a r o t i d b o d y t u m o r s , a n d s o

o n ) .

4 . C e r e b r o s p i n a l f lu id l e a k s .

Procedure

A f t e r p r e o p e r a t i v e e v a l u a t i o n h a s e s t a b l i s h e d j u g ­

u l a r b u l b i n v o l v e m e n t , a m o r e e x t e n s i v e a p p r o a c h t o

t h e s k u l l b a s e i s i n d i c a t e d fo r t o t a l t u m o r r e m o v a l

w i t h t h e s m a l l e s t r i sk o f m o r b i d i t y o r m o r t a l i t y .

T h e p a t i e n t i s p l a c e d i n t h e s u p i n e p o s i t i o n . T h e

i n v o l v e d s i d e i s s h a v e d , p r e p a r e d , a n d d r a p e d i n t h e

u s u a l s t e r i l e m a n n e r ; t h e s u r g i c a l f i e l d i n c l u d e s t h e

i p s i l a t e r a l n e c k . A p o s t a u r i c u l a r i n c i s i o n i s m a d e i n

a c u r v i l i n e a r f a s h i o n f o l l o w i n g t h e p o s t a u r i c u l a r

c r e a s e ( s l i g h t l y m o r e p o s t e r i o r t h a n for a s t a n d a r d

m a s t o i d e c t o m y ) ( F i g . 1 9 - 2 / 1 ) . T h e i n f e r i o r l i m b o f t h e

i n c i s i o n i s c a r r i e d i n t o t h e n e c k , e x t e n d i n g a l o n g t h e

a n t e r i o r b o r d e r o f t h e s t e r n o c l e i d o m a s t o i d m u s c l e .

A c o m p l e t e m a s t o i d e c t o m y i s p e r f o r m e d , d e l i n e ­

a t i n g t h e t e g m e n , s i g m o i d s i n u s ( e x p o s u r e i s e x ­

t e n d e d p o s t e r i o r l y t o t h e s i n u s ) , a n t r u m , a n d b o n y

l a b y r i n t h . T h e m a s t o i d t ip i s c o m p l e t e l y o p e n e d a n d

r e m o v e d . T h e e x t e r n a l a u d i t o r y c a n a l i s t r a n s e c t e d

w i t h a s c a l p e l a t t h e l e v e l o f t h e c a r t i l a g i n o u s - b o n y

j u n c t i o n a n d t h e n b r o u g h t f o r w a r d w i t h r e t r a c t o r s .

Temporomandibular

T u m o r s o f t h e M i d d l e a n d I n n e r E a r 329

T h e c a n a l i s t h i n n e d a n d a n e x t e n d e d facia l r e c e s s i s

o p e n e d t o t h e f l o o r o f t h e h y p o t y m p a n u m

T h e i n c u d o s t a p e d i a l j o i n t i s d i s l o c a t e d w i t h a j o i n t

k n i f e a n d t h e i n c u s i s r e m o v e d . T h e t h i n n e d p o s t e r i o r

e x t e r n a l a u d i t o r y c a n a l i s t h e n r e m o v e d , a s w e l l a s

t h e t y m p a n i c m e m b r a n e , m a l l e u s , a n d s k i n o f t h e

b o n y e x t e r n a l a u d i t o r y c a n a l . T h e b o n y a n t e r i o r a n d

i n f e r i o r c a n a l i s a l s o r e m o v e d w i t h a d i a m o n d b u r

w h i l e p r e s e r v i n g t h e p e r i o s t e u m ( t h i s a i d s a n t e r i o r

e x p o s u r e a n d r e t r a c t i o n ) . T h e s t a p e s i s left i n t a c t .

W i t h a d i a m o n d b u r , t h e b o n y f a l l o p i a n c a n a l i s

r e m o v e d f r o m t h e g e n i c u l a t e g a n g l i o n t o t h e s t y l o ­

m a s t o i d f o r a m e n . T h e fac ia l n e r v e i s m o b i l i z e d a n d

t r a n s p o s e d a n t e r i o r l y . A sof t t i s s u e s l i n g m a y b e

c r e a t e d t o h e l p h o l d t h e n e r v e o u t o f t h e f i e ld . W i t h

t h e f a c i a l n e r v e n o w l o c a t e d a n t e r i o r l y , a n o b s t r u c t e d

v i e w o f t h e j u g u l a r b u l b a n d t u m o r i s p o s s i b l e ( F i g .

1 9 - 2 8 , C ) . W i t h l a r g e c e r e b e l l a r r e t r a c t o r s , t h e m a n ­

d i b l e c o n d y l e m a y b e d i s l o c a t e d a n d r e t r a c t e d a n t e ­

r i o r ly for a n a d d i t i o n a l 1 - t o 2 - c m e x p o s u r e t o t h e

i n f r a t e f r t po ra ! r e g i o n . C a r e m u s t b e t a k e n n o t t o

i n j u r e t h e t r a n s p o s e d fac ia l n e r v e w i t h t h e r e t r a c t o r s .

I f n e c e s s a r y , t h e m a n d i b l e r a m u s m a y b e t r a n s e c t e d .

D e c o m p r e s s i o n o f t h e s i g m o i d s i n u s m u s t b e c o m ­

p l e t e d t o a l l o w for d i s t a l c o n t r o l o f v e n o u s b l e e d i n g .

B o n e d e c o m p r e s s i o n i s p e r f o r m e d f r o m j u s t b e l o w

t h e s i n o d u r a l a n g l e a n d c a r r i e d i n t e r i o r l y t o t h e

j u g u l a r b u l b ( o r t u m o r ) . I n t e r i o r l y , t h e b o n e o v e r t h e

p o s t e r i o r f o s s a a l s o i s r e m o v e d . T h e t u m o r c a n n o w

b e c l e a r l y v i s u a l i z e d f r o m t h e j u g u l a r b u l b , w i t h i ts

e x t e n s i o n i n t o t h e m i d d l e e a r o r m a s t o i d

T h e n e c k i s n o w e n t e r e d t o o b t a i n p r o x i m a l e x ­

p o s u r e a n d c o n t r o l o f t h e j u g u l a r v e i n a n d c a r o t i d

a r t e r y . I f n o t a l r e a d y a c c o m p l i s h e d , t h e m a s t o i d

p r o c e s s a t t a c h m e n t s o f t h e s t e r n o c l e i d o m a s t o i d a n d

d i g a s t r i c m u s c l e s a r e s h a r p l v d i s s e c t e d a n d r e f l e c t e d

a n t e r i o r l v . T h e l a t e r a l p r o c e s s o f t h e first c e r v i c a l

v e r t e b r a i s p a l p a t e d . J u s t i n f e r i o r t o t h i s p r o c e s s i s

t he e l e v e n t h n e r v e . B y f o l l o w i n g t h i s n e r v e f o r w a r d ,

t he j u g u l a r v e i n i s f o u n d . T h e r e l a t i o n s h i p o f t h e

e l e v e n t h n e r v e t o t h e v e i n v a r i e s ; m o s t c o m m o n l y i t

r u n s l a t e r a l l y t o t h e j u g u l a r v e i n , b u t o c c a s i o n a l l y i t

r u n s m e d i a l l y . T h e v e i n i s i s o l a t e d , t i e s a r e p l a c e d ,

a n d t h e v e i n i s l i g a t e d m e d i a l t o t h e t u m o r for

p r o x i m a l c o n t r o l . D i s t a l c o n t r o l i s a c c o m p l i s h e d a t

t h e d e c o m p r e s s e d s i g m o i d s i n u s . U s u a l l y p a c k i n g i s

u s e d e i t h e r e x t r a l u m i n a l l y o r i n t r a l u m i n a l l y a f t e r a n

o p e n i n g i s m a d e i n t h e l u m e n ( F i g . 1 9 - 3 / 1 ) . T h e

c a r o t i d a r t e r y i s i d e n t i f i e d a n d i s o l a t e d i n c a s e i n j u r y

o c c u r s , r e q u i r i n g c o n t r o l o f b l e e d i n g .

W i t h t o t a l e x p o s u r e n o w a c c o m p l i s h e d , t u m o r

r e m o v a l i s b e g u n . T h e s u p e r i o r b o r d e r i s m o b i l i z e d

f rom a g a i n s t t h e b o n y l a b y r i n t h . A n t e r i o r l y t h e t u m o r

i s m o b i l i z e d u n l e s s t h e r e i s i n v o l v e m e n t w i t h a n d

a d h e r e n c e t o t h e c a r o t i d a r t e r y . R e m o v a l b e g i n s

i n f e r i o r l y w h e r e t h e j u g u l a r v e i n w a s t r a n s e c t e d .

D i s s e c t i o n b e g i n s h e r e a n d c o n t i n u e s s u p e r i o r l y ,

d e v e l o p i n g a n d f o l l o w i n g a p l a n e b e t w e e n t h e t u m o r

a n d c a r o t i d . A n t e r i o r l y t h e c a r o t i d a r t e r y o f t e n i s

i n v o l v e d w i t h l a r g e r t u m o r s a n d p r e s e n t s a f o r m i ­

d a b l e t a s k t o s a f e l y m o b i l i z e a n d s e p a r a t e t h e t u m o r .

I n f r a t e m p o r a l l y , w h e r e t h e c a r o t i d t u r n s t o i t s h o r i ­

z o n t a l c o u r s e , a s m a l l b r a n c h ( c a r o t i c o t y m p a n i c

b r a n c h ) o f t e n s u p p l i e s t h e t u m o r a n d p r e s e n t s a

p a r t i c u l a r l y t r o u b l e s o m e p r o b l e m . I d e a l l y i t i s d i s ­

s e c t e d a s h o r t d i s t a n c e f r o m t h e c a r o t i d l e s i o n t o

a f f o r d a n o p p o r t u n i t y t o s a f e l y c o n t r o l it; h o w e v e r ,

i t m a y b e a v u l s e d , i n j u r i n g t h e c a r o t i d l u m e n a t a

p o i n t w h e r e d i s t a l c o n t r o l o f b l e e d i n g i s d i f f i c u l t . I f

c a r o t i d i n j u r y o c c u r s , r e p a i r o f t h e l u m e n w i t h a f i n e

a r t e r i a l s u t u r e (if p r o x i m a l a n d d i s t a l c o n t r o l c a n b e

o b t a i n e d ) s h o u l d b e a t t e m p t e d . I f t h i s c a n n o t b e

a c c o m p l i s h e d , p a c k i n g o f t h e a r e a wi l l c o n t r o l t h e

b l e e d i n g ( w i t h i ts a c c o m p a n y i n g r i s k o f s e v e r e m o r ­

b i d i t y o r m o r t a l i t y ) .

A s t h e t u m o r d i s s e c t i o n c o n t i n u e s s u p e r i o r l y , t h e

n i n t h , t e n t h , e l e v e n t h , a n d t w e l f t h c r a n i a l n e r v e s

wi l l b e e n c o u n t e r e d . A n a t t e m p t s h o u l d b e m a d e t o

i d e n t i f y t h e s e n e r v e s a n d p r e s e r v e t h e m i f p o s s i b l e .

O f t e n t h e y a r e i n t i m a t e l y i n v o l v e d w i t h t h e t u m o r

m a s s ( o r a r e d i f f i c u l t t o i d e n t i f y ) , a n d a r e s a c r i f i c e d

o r i n j u r e d .

A t t h e l e v e l o f t h e j u g u l a r b u l b a n d s i g m o i d s i n u s ,

t he m e d i a l w a l l o f t h e s i n u s i s d i s s e c t e d f r o m t h e

t u m o r m a s s , l e a v i n g t h e d u r a i n t a c t ( F i g . 1 9 - 3 8 ) .

P r o f u s e b l e e d i n g i s e n c o u n t e r e d i n t h e a r e a o f t h e

b u l b f r o m t h e i n f e r i o r p e t r o s a l s i n u s , w h i c h e m p t i e s

i n t o t h e b u l b o n i t s m e d i a l s i d e . P a c k i n g i s n e e d e d

t o c o n t r o l t h i s b l e e d i n g , s i n c e t h e r e i s n o w a y t o

o b t a i n c o n t r o l o f t h i s s i n u s .

F o l l o w i n g d i s s e c t i o n a n t e r i o r l y a n d p o s t e r i o r l y ,

t h e t u m o r m a s s i s h i n g e d i n t h e h y p o t y m p a n i c ,

i n f r a l a b y r i n t h i n e a r e a a n d i s r e m o v e d c a r e f u l l y . I f

i n t r a c r a n i a l e x t e n s i o n i s p r e s e n t , a c e r e b r o s p i n a l f luid

l e a k wi l l b e e n c o u n t e r e d u p o n t u m o r m a n i p u l a t i o n .

T u m o r b u l k m a y b e r e m o v e d t o i m p r o v e v i s u a l i z a ­

t i o n , a n d t h e d u r a m a y b e o p e n e d w i d e r t o e n h a n c e

p o s t e r i o r f o s s a e x p o s u r e . A s m a l l i n t r a c r a n i a l e x t e n ­

s i o n m a y t h e n b e c a r e f u l l y r e m o v e d , p r o t e c t i n g a n d

p r e s e r v i n g i n t r a c r a n i a l s t r u c t u r e s ( a n t e r o i n f e r i o r a n d

p o s t e r o i n f e r i o r c e r e b e l l a r a r t e r i e s , b r a i n s t e m , c r a n i a l

n e r v e s , a n d s o o n ) .

A f t e r t h e t u m o r h a s b e e n c o m p l e t e l y r e m o v e d ,

t h e d u r a l d e f e c t i s c l o s e d w i t h e i t h e r f ree a b d o m i n a l

fat o r a m u s c l e p l u g . T h e t r a n s p o s e d fac ia l n e r v e i s

r e l e a s e d a n d p l a c e d i n a t e n s i o n - f r e e p o s i t i o n . T h e

t r a n s e c t e d e x t e r n a l a u d i t o r y c a n a l i s e v e r t e d a n d

c l o s e d w i t h a p e r m a n e n t s u t u r e ( r e s u l t i n g i n a b l i n d

p o u c h ) . T h e p o s t a u r i c u l a r i n c i s i o n i s c l o s e d i n l a y e r s

a n d d r e s s i n g s a r e a p p l i e d . O c c a s i o n a l l y for l a r g e

330 T u m o r s o f t h e M i d d l e a n d I n n e r t a r

Jugular vein

Sigmoid sinus packed

Sigmoid sinus (medial wall)

FIGURE ] 9 - 3

T u m o r s o f t h e M i d d l e a n d I n n e r E a r 3 3 1

d u r a l d e f e c t s , l u m b a r d r a i n s a r e p l a c e d a t t h e e n d o f

t h e p r o c e d u r e t o h e l p p r e v e n t c e r e b r o s p i n a l f lu id

l e a k a g e .

Translabyrinthine Approach for Acoustic Neuromas

Aim

W i d e e x p o s u r e o f t h e t u m o r w i t h e a r l y i d e n t i f i c a ­

t i on o f t h e fac ia l n e r v e , a l l o w i n g for t o t a l e x c i s i o n o f

t h e t u m o r w i t h p r e s e r v a t i o n o f t h e n e r v e .

Highlights

1 . T h e i n c i s i o n i s m o r e p o s t e r i o r t h a n t h e u s u a l

p o s t a u r i c u l a r i n c i s i o n .

2 . D r i l l i n g i s d o n e p o s t e r i o r t o t h e s i g m o i d s i n u s

i n o r d e r t o a l l o w p o s t e r i o r d e c o m p r e s s i o n ( r e t r a c t i o n )

o f it.

3 . T h e i n t e r n a l a u d i t o r y c a n a l i s i d e n t i f i e d a n d t h e

p o s t e r i o r h a l f o f t h e b o n e i s r e m o v e d .

4 T h e fac ia l n e r v e i s i d e n t i f i e d a t B i l l ' s b a r a s i t

b e g i n s i ts l a b y r i n t h i n e c o u r s e .

5 . T h e s u p e r i o r a n d i n f e r i o r v e s t i b u l a r n e r v e s a n d

t h e c o c h l e a r n e r v e a r e a v u l s e d .

6 . T h e t u m o r i s r e m o v e d a w a y f r o m t h e facial

n e r v e .

Pitfalls

1 . F a i l i n g t o a d e q u a t e l y d e c o m p r e s s t h e s i g m o i d

s i n u s a n d t o r e m o v e b o n e f r o m t h e p o s t e r i o r f o s s a

d u r a .

2 . F a i l i n g t o o p e n t h e i n t e r n a l a u d i t o r y c a n a l

w i d e l y for full e x p o s u r e o f t h e t u m o r .

3 . F a i l i n g t o p o s i t i v e l y i d e n t i f y t h e fac ia l n e r v e

b e f o r e a v u l s i n g n e r v e s .

4 . S t r e t c h i n g (o r c o m p l e t e l y t r a n s e c t i n g ) t h e fac ia l

n e r v e d u r i n g t u m o r r e m o v a l .

5 . I n c o m p l e t e l y r e m o v i n g t h e t u m o r .

Procedure

F o r t h i s a p p r o a c h t h e p a t i e n t l i es s u p i n e . P r e p a ­

ra t ion a n d d r a p i n g a r e t h e s a m e a s for a s t a n d a r d

e a r p r o c e d u r e w i t h t h e e x c e p t i o n o f a l a r g e r h e a d

s h a v e . B y p l a c i n g t h e p a t i e n t ' s h e a d a t t h e foo t o f

t he t a b l e , t h e s u r g e o n wil l h a v e r o o m for h i s o r h e r

l e g s u n d e r t h e t a b l e a n d b e m o r e c o m f o r t a b l e . T h e

p a t i e n t m u s t b e s e c u r e l y s t r a p p e d t o t h e t a b l e , s i n c e

f r e q u e n t s i d e - t o - s i d e r o t a t i o n i s n e e d e d .

T h e p o s t a u r i c u l a r i n c i s i o n i s d e s i g n e d a s u s u a l b u t

l o c a t e d f a r t h e r p o s t e r i o r l y , t o a l l o w d r i l l i n g p o s t e r i o r

t o t h e s i g m o i d s i n u s ( F i g . 1 9 - 4 / 1 ) . T h i s i s e s s e n t i a l

for c o m p l e t e d e c o m p r e s s i o n o f t h e s i g m o i d s i n u s a n d

o p t i m a l l a t e r v i s u a l i z a t i o n i n t o t h e c e r e b e l l o p o n t i n e

a n g l e ; i f a n e r r o r i s m a d e , i t s h o u l d b e m a d e i n

m a k i n g t h e i n c i s i o n t o o far p o s t e r i o r . T h e i n c i s i o n

l i e s 1 t o l ' /2 i n ( i t i t s m o s t p o s t e r i o r p o s i t i o n ) b e h i n d

t h e a u r i c l e a n d r u n s i n a n e x t e n d e d C s h a p e . I t i s

c a r r i e d t h r o u g h t h e p e r i o s t e u m o f t h e m a s t o i d c o r t e x ,

a v o i d i n g t h e t e m p o r a l m u s c l e s u p e r i o r l y , T h e p e r i ­

o s t e u m i s t h e n e l e v a t e d a n d t h e e a r h e l d f o r w a r d

w i t h c e r e b e l l a r r e t r a c t o r s . R e t r a c t o r s p l a c e d i n t h e

s u p e r i o r - t o - i n f e r i o r d i r e c t i o n wi l l h o l d t h e t e m p o r a l

m u s c l e o u t o f t h e s u r g i c a l f i e l d .

U s i n g t h e l a r g e s t c u t t i n g b u r a n d s u c t i o n i r r iga ­

t i o n , d r i l l i n g i s b e g u n . T h e m a s t o i d c o r t e x i s r e m o v e d

as in a r o u t i n e m a s t o i d e c t o m y . C a r e i s t a k e n to

s a u c e r i z e t h e e d g e s a n d k e e p t h e l a t e r a l m o s t o p e n i n g

a s w i d e a s p o s s i b l e . I n t h i s p r o c e d u r e , i t i s i m p o r t a n t

t o e x t e n d t h e d r i l l i n g p o s t e r i o r t o t h e s i g m o i d s i n u s .

T h i s b o n e r e m o v a l i s c o m p l e t e d d o w n t o t h e p o s t e ­

r io r f o s s a d u r a . F o r l a r g e t u m o r s , t h e p o s t e r i o r d i s ­

s e c t i o n m a y e x t e n d 1 t o I 1 / ; i n b e h i n d t h e s i g m o i d

s i n u s . F i n a l b o n e r e m o v a l i s a c c o m p l i s h e d l a t e r w i t h

t h e d i a m o n d b u r t o a v o i d t e a r i n g o f t h e d u r a a n d

s u b s e q u e n t c e r e b e l l a r h e r n i a t i o n . I n t h i s a r e a e m i s ­

s a r y v e i n s a r e f o u n d r u n n i n g f r o m t h e s i g m o i d s i n u s

t o t h e c o r t e x ; o c c a s i o n a l l y q u i t e l a r g e , t h e y m a y b e a

s o u r c e o f t r o u b l e s o m e b l e e d i n g a n d m u s t b e a p ­

p r o a c h e d c a u t i o u s l v .

A t t h i s p o i n t t h e o p e r a t i n g m i c r o s c o p e i s b r o u g h t

i n t o t h e f i e ld . T h e m a s t o i d e c t o m y i s c o m p l e t e d a s

d e s c r i b e d i n p r e v i o u s c h a p t e r s , a f t e r w h i c h s t e p t h e

s u r g e o n s h o u l d b e a b l e t o i d e n t i f y d e f i n i t e l y t h e

h o r i z o n t a l a n d p o s t e r i o r s e m i c i r c u l a r c a n a l s . W i t h

t h i s b a s i c l a n d m a r k , t h e p o s i t i o n s o f t h e i n c u s , fac ia l

n e r v e , a n d p o s t e r i o r s e m i c i r c u l a r c a n a l a r e k n o w n

e v e n i f t h e y a r e n o t y e t fu l ly s e e n . B o n e o v e r t h e

t e g m e n , s i g m o i d s i n u s , p o s t e r i o r f o s s a , s i n o d u r a l

a n g l e , a n d e x t e r n a l a u d i t o r y c a n a l i s t h i n n e d t o a l l o w

full e x p o s u r e a n d d e e p e r d i s s e c t i o n . I f t h e s i g m o i d

s i n u s i s d i s p l a c e d a n t e r i o r l y , i t m a y b e d e c o m p r e s s e d

a t t h i s s t a g e ; i f i t i s p o s s i b l e t o p e r f o r m t h e l a b y r i n -

t h e c t o m y n o w , i t m a y b e b e t t e r t o d e l a y t h e a c t u a l

d e c o m p r e s s i o n . T h i s p r e v e n t s t h e p r o b l e m o f c e r e ­

b e l l a r h e r n i a t i o n i f t h e d u r a i s i n a d v e r t e n t l y o p e n e d

o r o f v i s i o n b e i n g o b s t r u c t e d b y p a c k i n g i f t h e s i n u s

i s i n j u r e d .

T u m o r s o f t h e M i d d l e a n d I n n e r E a r 333

A full l a b y r i n t h e c t o m y h a s b e e n d i s c u s s e d in p r e ­

v i o u s c h a p t e r s . D i s s e c t i o n i s s t a r t e d i n t h e a r e a o f

t h e c o m m o n c r u s ( j u s t a n t e r i o r t o t h e s i n o d u r a l

a n g l e ) ; t h i s i s t h e s a f e s t p l a c e t o b e g i n , s i n c e t h e

facial n e r v e i s far a n t e r i o r . D i s s e c t i o n i s c o n t i n u e d

m e d i a l l y a n d i n t e r i o r l y u n t i l e a c h c a n a l i s f o u n d a n d

c o m p l e t e l y " d r i l l e d o u t . " R e m e m b e r t o k e e p t h e

s i n o d u r a l a n g l e c l e a n a n d w i d e l y o p e n t o a l l o w for

m a x i m u m e x p o s u r e l a t e r . T h e b o n e h e r e i s t h i n n e d ,

a n d t h e s u p e r i o r p e t r o s a l s i n u s i s s e e n a s i t r u n s

f r o m t h e s i g m o i d t o t h e p e t r o u s a p e x ( F i g . 1 9 - 4 B ) .

T h e p o s t e r i o r c a n a l i s e n c o u n t e r e d f i r s t a n d f o l l o w e d

a s i t c o u r s e s a n t e r o i n f e r i o r l y . I n a p p r o a c h i n g t h e

a m p u l l a , b e a w a r e t h a t t h e facial n e r v e i s j u s t l a t e r a l

i n o r d e r t o a v o i d i n j u r y t o i t . T h e j u g u l a r b u l b l ies

i n f e r i o r t o t h e p o s t e r i o r c a n a l a n d r a r e l y m a y b e s o

h i g h a s t o t o u c h t h e p o s t e r i o r c a n a l . B y f o l l o w i n g t h e

c o m m o n c r u s m e d i a l l y , t h e s u p e r i o r s e m i c i r c u l a r

c a n a l c a n b e e n t e r e d a n d t h e n f o l l o w e d i n i ts a n t e r o -

s u p e r i o r c o u r s e . R e m e m b e r t h a t t h i s c a n a l l i e s i n a

m u c h ' d e e p e r ( m e d i a l ) p l a n e t h a n t h e o t h e r t w o

c a n a l s . A s t h e - a m p u l l a o f t h e s u p e r i o r c a n a l i s e n ­

t e r e d , i t i s left p a r t i a l l y i n t a c t to p r o v i d e a l a t e r

l a n d m a r k t o t h e s u p e r i o r v e s t i b u l a r n e r v e a n d l a t e r a l -

m o s t e n d o f t h e i n t e r n a l a u d i t o r y c a n a l . A s t h e

d i s s e c t i o n c o n t i n u e s a n t e r i o r l y ( f o r w a r d ) , t h e l a te ra l

c a n a l i s o p e n e d c o m p l e t e l y ; t h e s i d e o f t h e c u t t i n g

b u r ( n o t t h e t ip ) i s u s e d , a l l o w i n g for a s a f e r a p p r o a c h

w i t h b e t t e r v i s u a l i z a t i o n o f t h e fac ia l n e r v e . U s i n g

t h e d i a m o n d b u r , t h e fac ia l n e r v e i s p o s i t i v e l y i d e n ­

t i f i ed . T h i s m a r k s t h e a n t e r i o r l imi t o f t h e d i s s e c t i o n .

C a r e f u l l y s k e l e t o n i z i n g t h e fac ia l n e r v e a f f o r d s a s

m u c h r o o m a s p o s s i b l e for full v i s u a l i z a t i o n o f t h e

v e s t i b u l e a n d , l a t e r , t h e l a t e ra l e n d o f t h e i n t e r n a l

a u d i t o r y c a n a l .

T h e f ina l s t e p s a r e t o ful ly o p e n t h e v e s t i b u l e a n d

t o c o m p l e t e l y t h in t h e m i d d l e fo s sa t c g m e n , s i n o ­

d u r a l a n g l e , a n d p o s t e r i o r fo s sa d u r a t o t h e l e v e l t h a t

t h e d i s s e c t i o n h a s r e a c h e d . T h e d i s s e c t i o n i s c a r r i e d

i n t e r i o r l y t o i d e n t i f y t h e j u g u l a r b u l b ; s e e n a s a b l u i s h

d i s c o l o r a t i o n t h r o u g h t h e b o n e , i t r e p r e s e n t s t h e

i n f e r i o r l i m i t o f d i s s e c t i o n . A s t h e d i s s e c t i o n i s c a l l e d

i n t e r i o r l y , t h e r e t r o f a c i a l a i r c e l l s o f t e n a r e o p e n e d t o

e n h a n c e e x p o s u r e . A l s o f o u n d i n t h i s a r e a i s t h e

v e s t i b u l a r a q u e d u c t a s i t r u n s m e d i a l l y t o t h e p o s t e ­

r io r c a n a l f r o m t h e e n d o l y m p h a t i c s a c . T h e l a b y r i n ­

t h e c t o m y h a s n o w b e e n c o m p l e t e d .

I m m e d i a t e l y m e d i a l t o t h e v e s t i b u l e l ies t h e i n t e r ­

nal a u d i t o r y c a n a l ( r e m e m b e r t h a t t h e m e d i a l w a l l o f

t he s u p e r i o r c a n a l a m p u l l a i s t h e l a t e ra l w a l l o f t h i s

c a n a l ) . A t t h i s p o i n t , t h e s i g m o i d s i n u s s h o u l d b e

d e c o m p r e s s e d s o t h a t i t c a n b e r e t r a c t e d p o s t e r i o r l y ,

t h i s p r o v i d e s m o r e w o r k i n g a r e a , e s p e c i a l l y p o s t e ­

r i o r l y a t t h e b r a i n s t e m - t u m o r j u n c t i o n . A l a r g e d i a ­

m o n d b u r a n d c o n s t a n t i r r i g a t i o n i s u s e d t o t h in t h e

b o n e o v e r t h e e n t i r e s i n u s . F i n a l b o n e r e m o v a l i s

a c c o m p l i s h e d w i t h t h e d i a m o n d b u r o r a b l u n t p i c k .

A t h i n i s l a n d o f b o n e ( B i l l ' s i s l a n d ) i s left o v e r t h e

e x p o s e d s i n u s t o p r e v e n t i n j u r y f r o m t h e s h a n k o f

t h e b u r w h e n d e e p e r d i s s e c t i o n i s r e s u m e d . B o n e

m a y b e r e m o v e d p o s t e r i o r t o t h e s i n u s e x p o s i n g t h e

d u r a a n d a l l o w i n g m o r e r e t r a c t i o n w i t h i n c r e a s e d

v i s u a l i z a t i o n i n t o t h e i n t e r n a l a u d i t o r y c a n a l a n d

c e r e b e l l o p o n t i n e a n g l e . T h e t h i n n e d b o n e i s t h e n

r e m o v e d f r o m t h e p o s t e r i o r f o s s a m e d i a l t o t h e

s i g m o i d s i n u s t o t h e l e v e l t h a t t h e d i s s e c t i o n h a s

r e a c h e d ; t h i s i s d o n e w i t h t h e d i a m o n d b u r , s u c t i o n ,

a n d b l u n t i n s t r u m e n t s . C a r e m u s t b e t a k e n n o t t o

t e a r t h e d u r a ( t o p r e v e n t c e r e b e l l a r h e r n i a t i o n a n d

a v o i d v e s s e l s ' t h a t m a y l ie i m m e d i a t e l y u n d e r n e a t h )

o r t o r u p t u r e t h e s u p e r i o r p e t r o s a l s i n u s b e h i n d t h e

s i n o d u r a l a n g l e . W i t h l a r g e t u m o r s , t h e w o r k i n g a r e a

i s i m p r o v e d r e m o v i n g b o n e f r o m t h e p o s t e r i o r

e n d o f t h e t e g m e n , a l l o w i n g a b e t t e r a n g l e for i n s t r u ­

m e n t a t i o n .

W i t h t h e s u p e r i o r , i n f e r i o r , a n d a n t e r i o r l i m i t s

n o w w e l l d e f i n e d , full a t t e n t i o n i s g i v e n t o t h e

i n t e r n a l a u d i t o r y c a n a l . T h e o b j e c t i v e i s t o o b t a i n

1 8 0 - d e g r e e b o n e r e m o v a l o f t h e p o s t e r i o r h a l f o f t h e

c a n a l . T h i s i s n e c e s s a r y f o r full e x p o s u r e a n d t o

p r e v e n t b o n y o v e r h a n g s t h a t h i n d e r w o r k w i t h i n t h e

c a n a l . T w o i m p o r t a n t p o i n t s m u s t b e r e m e m b e r e d .

( I ) T h e c a n a l r u n s a n t e r i o r t o p o s t e r i o r a s i t b e c o m e s

m o r e m e d i a l ; t h u s m o r e b o n e wil l b e r e m o v e d n e a r

t h e p o s t e r i o r f o s s a d u r a , a n d o n l y m i n i m a l b o n e

r e m o v a l wi l l b e n e e d e d a t t h e s u p e r i o r c a n a l a m p u l l a

l a n d m a r k ( w h i c h w a s left b e h i n d ) . T h e c o u r s e i t w i l l

r u n a p p r o x i m a t e s a l i ne f r o m t h e s e c o n d g e n u o f t h e

fac ia l n e r v e t o t h e s i n o d u r a l a n g l e . (2 ) T h e c a n a l will

b e v e r y e x p a n d e d o w i n g t o t h e p r e s e n c e o f t h e t u m o r

( F i g . 1 9 - 4 C ) .

B o n y t r o u g h s a r e c r e a t e d a r o u n d t h e s u p e r i o r a n d

i n f e r i o r b o r d e r s o f t h e i n t e r n a l a u d i t o r y c a n a l ; t h e y

a r e d e e p e n e d b e t w e e n t h e t e g m e n a n d t h e c a n a l a n d

b e t w e e n t h e j u g u l a r b u l b a n d t h e c a n a l , r e s p e c t i v e l y ,

un t i l t h e p o s t e r i o r h a l f o f t h e c a n a l h a s b e e n e x p o s e d

a n d t h e b o n e h a s b e e n t h i n n e d t o e g g s h e l l t h i c k n e s s .

S u p e r i o r l y , c a u t i o n i s n e e d e d s i n c e o c c a s i o n a l l y t h e

fac ia l n e r v e c r o s s e s t h e s u p e r i o r a s p e c t o f t h e t u m o r

a n d m a y b e i n j u r e d w i t h t h e d i a m o n d b u r . T h e b u r

bi t s h o u l d a l w a y s r o t a t e t o w a r d t h e t e g m e n , t o p r e ­

v e n t " j u m p i n g " i n t o t h e c a n a l i f i t c a t c h e s o n a b o n y

l e d g e ; t h i s i n v o l v e s c l o c k w i s e r o t a t i o n in a left e a r

a n d c o u n t e r c l o c k w i s e r o t a t i o n i n a r i gh t e a r . I n d e ­

v e l o p i n g t h e " t r o u g h " i n t e r i o r l y , t h e c o c h l e a r a q u e ­

d u c t i s f o u n d b e t w e e n t h e j u g u l a r b u l b a n d t h e c a n a l .

I t u s u a l l y a p p e a r s as a w h i t e s p o t , a n d i n s e r t i n g a

p i c k i n t o i t o f t e n p r o d u c e s a c e r e b r o s p i n a l f lu id l e a k .

T h i s i s a n i m p o r t a n t l a n d m a r k , s i n c e t h e n i n t h n e r v e

i s j u s t a n t e r o i n f e r i o r a n d m e d i a l to i t a s i t e x i t s t h e

334 T u m o r s o f t h e M i d d l e a n d I n n e r E a r

sku l l t o p r o c e e d a c r o s s t h e m e d i a l s u p e r i o r a s p e c t o f

t h e j u g u l a r b u l b . I n o r d e r t o p r o t e c t t h i s n e r v e ,

d i s s e c t i o n s h o u l d n o t p r o c e e d a n t e r i o r l y t o t h e c o c h ­

l e a r a q u e d u c t . F o c u s i n g o n t h e s u p e r i o r c a n a l a m ­

p u l l a , t h e s u p e r i o r v e s t i b u l a r n e r v e c a n b e i d e n t i f i e d

t h r o u g h t h e b o n e b y c a r e f u l d i s s e c t i o n w i t h a d i a ­

m o n d b u r . W i t h c o n t i n u o u s o n p i o u s i r r i g a t i o n t o

p r e v e n t h e a t t r a n s f e r f r o m t h e b u r , t h e fac ia l n e r v e

c a n b e b l u e - l i n e d a n d i d e n t i f i e d a s i t e n t e r s t he

l a b y r i n t h i n e p o r t i o n o f t h e f a l l o p i a n c a n a l , m e d i a l

a n d s l i g h t l y s u p e r i o r t o w h e r e t h e s u p e r i o r v e s t i b u l a r

n e r v e e n d s . (It m a y b e f o l l o w e d for a s h o r t d i s t a n c e

i n its l a b y r i n t h i n e c o u r s e for p o s i t i v e i d e n t i f i c a t i o n . )

I n f e r i o r t o t h e s u p e r i o r v e s t i b u l a r n e r v e i s t he t r a n s ­

v e r s e c r e s t , w h i c h d i v i d e s t h e l a t e r a l m o s t e n d o f t h e

i n t e r n a l a u d i t o r y c a n a l i n t o s u p e r i o r a n d in fe r io r

c o m p a r t m e n t s ( F i g . 1 9 - 5 / 4 ) . I f t h e b o n e r e m a i n i n g

o v e r t h e c a n a l h a s b e e n t h i n n e d p r o p e r l y , u s u a l l y i t

can b e c r a c k e d w i t h p r e s s u r e f r o m a b l u n t i n s t r u m e n t

a n d r e m o v e d i n o n e p i e c e , o r d r i l l e d c a r e f u l l y w i t h

a d i a m o n d b u r . I t i s i m p o r t a n t t o c o m p l e t e l y r e m o v e

t h e b o n e f r o m t h e p o s t e r i o r h a l f o f t h e c a n a l . T h e

t u m o r i t s e l f i s n o w e x p o s e d a n d b o n e o v e r l y i n g t h e

p o s t e r i o r f o s s a d u r a h a s b e e n r e m o v e d c o m p l e t e l y ,

f rom t h e s i g m o i d s i n u s t o t h e p o m s a c u s t i c u s ( l a te ra l

t o m e d i a l ) a n d f rom t h e t e g m e n t o t h e j u g u l a r b u l b

( s u p e r i o r t o i n f e r i o r ) .

A d u r a l f l ap i n c i s i o n i s b e g u n p o s t e r o s u p e r i o r l y

t o t h e j u g u l a r b u l b , a n d c a r r i e d a c r o s s t h e p o r u s

a c u s t i c u s a n d t h e n l a t e r a l l y u p t h e p o s t e r i o r fossa

d u r a p a r a l l e l t o t he s u p e r i o r p e t r o s a l s i n u s . I ts infe­

rior l i m b n i a v b e c a r r i e d l a t c r a l l v a l o n g ( h e s i g m o i d

s i n u s . I he Hap i s p u l l e d b a c k w a r d a n d t h e p o s t e r i o r

s u r f a c e o f t h e t u m o r i s \ i s u a l i / e d ( F i g . IS* ^ / * ) . I he

i n c i s i o n s m u s t h e m a d e c a u t i o u s l v s o tha t a n v un­

d e r l y i n g v e s s e l s a n d n e r v e s a r e no t i n j u r e d . K a r e l v .

t he tac ia l n e r v e t r a v e r s e s t h e s u p v r i o r a s p e c t o l t he

t u m o r ( U M U I I V i t i s o n t h e . i n t e r i o r s u r l i i i e ) ; t h e

p e t r o s a l v e i n i s l o u n d a l o n g l l i r p o s t e r i o r a s p e c t ,

d r a i n i n g i n t o t h e s u p e r i o r p e t r o s a l v e i n . A t t h e tu­

m o r ' s i n f e r i o r a s p e c t , t h e c i s t e m a m a g n a u s u a l l v c a n

b e v i s u a l i z e d a n d g e n t l y p r o b e d t o o b t a i n a p r o f u s e

c e r e b r o s p i n a l f lu id l e a k . Th i s wi l l r e l e a s e p r e s s u r e

a n d a l l o w t h e c e r e b e l l u m t o r e l a x . The p l a n e b e t w e e n

the p o s t e r i o r a s p e c t o f t h e t u m o r a n d t h e a r a c h n o i d

i s d e v e l o p e d , a n d t h e d u r a l f lap i s la id i n t h e p l a n e

t o p r o t e c t t h e c e r e b e l l u m (if p o s s i b l e , i n c l u d e t h e

p e t r o s a l v e i n u n d e r t h e f l a p ) . L o n g C o t t o n o i d s t r i p s

m a y a l s o b e la id t o p r o t e c t t h e c e r e b e l l u m a n d h e l p

i n d e v e l o p i n g t h e p l a n e . D e v e l o p i n g t h e p r o p e r p l a n e

wil l p r o d u c e l e s s b l e e d i n g .

A t th i s p o i n t t he l a t e ra l e n d o f t he t u m o r i s

m o b i l i z e d f rom t h e facial n e r v e . B y r o t a t i n g t he t ab le

a w a y t h e a r e a i s b r o u g h t i n t o v i e w . T h e s u p e r i o r

v e s t i b u l a r a n d facia l n e r v e s a r e i d e n t i f i e d . U s i n g a

b l u n t r i g h t - a n g l e d h o o k , t h e r i d g e o f b o n e ( B i l l ' s b : r )

t h a t s e p a r a t e s t h e s u p e r i o r v e s t i b u l a r a n d fac a l

n e r v e s i s i d e n t i f i e d a n d p a l p a t e d by f i n d i n g t h e e* d

o f t h e s u p e r i o r v e s t i b u l a r n e r v e a n d f o l l o w i n g Hie

b o n e b a c k w a r d u n t i l i t e n d s ( w h i c h i s w h e r e t h e

facial c a n a l b e g i n s ) . T h i s i s c r u c i a l to p r e s e r v i n g H e

facial n e r v e , s i n c e e v e r y t h i n g l a t e r a l t o t h i s r i d g e i s

v e s t i b u l a r n e r v e a n d m a y b e a v u l s e d s a f e l y ( F i g . 1 9 -

5 C ) . A s t h e a v u l s e d n e r v e i s p u l l e d b a c k , t h e facial

n e r v e i s b r o u g h t i n t o full v i e w b e h i n d . I t i s b e s t n o t

t o p r o b e i n t o t h e fac ia l c a n a l i n o r d e r t o p r e v e n t

t r a u m a t o a n d s w e l l i n g o f t h e fac ia l n e r v e . T h e first

f e w m i l l i m e t e r s o f t h e fac ia l n e r v e a r e c l e a n e d o

i d e n t i f y i t p o s i t i v e l y . A r a c h n o i d t h a t e n v e l o p s \h?.

n e r v e o n i ts s u p e r i o r a n d i n f e r i o r e d g e s i s s e p a r a t e d

w i t h t h e h o o k ( F i g . 1 9 - 5 D ) . O f t e n t h i s i s diff ice. j ,

s i n c e t h e n e r v e m a y t h i n c o n s i d e r a b l y a n d m a k e t h e

n e r v e e d g e s h a r d t o d i s t i n g u i s h . I n f e r i o r t o t h e s i -

p e r i o r v e s t i b u l a r n e r v e i s t h e t r a n s v e r s e c r e s t ; s

m e n t i o n e d p r e v i o u s l y , i t s e p a r a t e s t h e s u p e r i o r a - i

i n f e r i o r c o m p a r t m e n t s o f t h e i n t e r n a l a u d i t o r y c a n r .

T h e i n f e r i o r c o m p a r t m e n t i s c l e a n e d o f t u m o r w i l l

t h e h o o k . A t o n g u e o f t u m o r o f t e n e x t e n d s u/>

b e t w e e n t h e t r a n s v e r s e c r e s t a n d i n f e r i o r c o m p a r -

m e n t a n d m u s t b e s w e p t c l e a n ( F i g . 1 9 - 6 / A ) . T h £

i n f e r i o r v e s t i b u l a r n e r v e i s a v u l s e d , a n d u s u a l l y t he

c o c h l e a r n e r v e a s w e l l . T h e a n t e r o i n f e r i o r c e r e b e l l a r

a r t e r y u s u a l l y l i e s a l o n g t h e i n f e r i o r b o r d e r o f t h e

t u m o r , a n t e r i o r t o t h e c o c h l e a r n e r v e . T h i s i m p o r t e d *

v e s s e l m u s t a l w a y s b e w a t c h e d for a n d p r o t e c t ? - !

f rom i n j u r v . T h e t u m o r i s p u l l e d t o w a r d t h e s u r g e o n

d u r i n g th i s l a t e r a l m o b i l i z a t i o n .

I h e p r o c e d u r e t r o m t h i s p o i n t d e p e n d s o n t i e

s i / e o t t h e t u m o r . D i s s e c t i o n m a v p r o c e e d a s obo" i ;

h o w e v e r , for a l a r g e r t u m o r d e b u l k i n g wil l be •

q u i r e d , t o p r e v e n t t r a c t i o n f rom b e i n g p l a c e d on t . e

facial n e r v e a s [ l ie t u m o r i s r o l l ed a w a v I r o m it. i n

d e b u l k i n g , t h e t u m o r i s o p e n e d o v e r i ts p o s t e n * r

s u r f a c e a n d t h e c o n l v n t s , u e r e m o v e d " i n t r a c a p s a -

l a r l v , " a l l o w i n g i t t o c o l l a p s e i n w a r d . T h i s c a n v

a c c o m p l i s h e d w i t h an U r b a n d i s s e c t o r , l a s e r ( F i g . 1 f

b/*) , C a v i t r o n , o r c u p f o r c e p s . C a r e i s t a k e n t o r e m a i n

i n s i d e t h e c a p s u l e i n o r d e r t o p r e v e n t i n j u r y t o n e r v ' 5

o r v e s s e l s tha t m a y t r a v e r s e t h e t u m o r s u r f a c e . W : h

a d e q u a t e d e b u l k i n g t h e t u m o r wi l l c o l l a p s e i n w a r I ,

a l l o w i n g f u r t h e r m o b i l i z a t i o n f r o m t h e fac ia l n e r e

a n t e r i o r l y ( F i g . 1 9 - 6 C ) a n d t h e b r a i n s t e m p o s t e r i o r y

( F i g . 1 9 - 6 D ) . B i p o l a r c a u t e r y m a y be u s e d to c o n t ; >1

b l e e d i n g w i t h i n t h e t u m o r , w h i c h o c c a s i o n a l l y : s

a b u n d a n t . W i t h l a r g e t u m o r s , t h e n i n t h n e r v e m - v

t r a v e r s e t h e c a p s u l e i n t e r i o r l y . U s u a l l v t h e a n t e r o i . -

( e r i o r c e r e b e l l a r a r t e r y h a s b e e n p u s h e d i n f e r i o r l y '~y

t u m o r g r o w t h . S u p e r i o r l y t h e fifth n e r v e m a y ere? s

t he c a p s u l e i n l a r g e t u m o r s ; o c c a s i o n a l l y , t h e s e v e n ; i

n e r v e m a y t r a v e r s e t h e s u p e r i o r e d g e o f t h e t u m o : .

T u m o r s o f t h e M i d d l e a n d I n n e r E a r

FIGURE 19-5.

336 T u m o r s o f t h e M i d d l e a n d I n n e r E a r

FIGURE 19-6.

T u m o r s o f t h e M i d d l e a n d I n n e r E a r 337

D u r i n g m o b i l i z a t i o n a n d t u m o r r e m o v a l , t h e s e s t r u c ­

t u r e s m u s t b e w a t c h e d for a n d p r o t e c t e d .

A f t e r a d e q u a t e d e b u l k j n g , t h e p l a n e for t h e facial

n e r v e i s f u r t h e r d e v e l o p e d a n d t h e t u m o r c o n t i n u e s

t o b e r o l l e d t o w a r d t h e s u r g e o n . I t i s i m p o r t a n t

( a l t h o u g h d i f f i cu l t ) t o a v o i d p u s h i n g t h e t u m o r m a s s

i n w a r d , w h i c h m a y s t r e t c h t h e t h i n n e d n e r v e . I t i s

b e s t t o f o l l o w t h e fac ia l n e r v e t o t h e b r a i n s t e m ,

s e p a r a t i n g a n d r e m o v i n g t h e t u m o r a s t h e p l a n e

c o n t i n u e s t o b e d e v e l o p e d . A t t h e p o r u s a c u s t i c u s

t h e fac ia l n e r v e u s u a l l y t h i n s c o n s i d e r a b l y , m a k i n g

t h e d i s s e c t i o n d i f f i c u l t . O f t e n i t i s n e c e s s a r y t o r e t u r n

t o t h e p o s t e r i o r , i n f e r i o r , a n d s u p e r i o r b o r d e r s o f t h e

t u m o r t o d e v e l o p t h i s p l a n e ( i f n e e d e d for m a n e u ­

v e r i n g ) . A l w a y s t ry t o a v o i d p u s h i n g t h e t u m o r

a n t e r i o r l y . O n c e t h e fac ia l n e r v e h a s b e e n f r e e d f r o m

the t u m o r , t h e b u l k o f t h e t u m o r i s r e m o v e d t o

e n h a n c e v i s u a l i z a t i o n ( F i g . 1 9 - 6 / : ) . T h e p l a n e b e ­

t w e e n t h e r e m a i n i n g t u m o r a n d t h e b r a i n s t e m i s

d e v e l o p e d a n d c a r e i s e x e r c i s e d s u p e r i o r l y for t h e

fifth n e r v e a n d i n f e r i o r l v for t h e a n t e r o i n f e r i o r c e r e ­

b e l l a r a r t e r y ( F i g . 1 9 - 6 £ ) . V e s s e l s t h a t t r a v e r s e t h e

t u m o r s u r f a c e a r e d i s s e c t e d a w a y , i f p o s s i b l e ; i f n o t ,

t h e y a r e c a r e f u l l y c l i p p e d o r c a u t e r i z e d . W i t h c a r e f u l

d i s s e c t i o n , to ta l r e m o v a l o f t h e t u m o r c a n b e a c c o m ­

p l i s h e d i n a l m o s t all c a s e s .

B e f o r e c l o s u r e , s u f f i c i e n t t i m e m u s t b e t a k e n t o

e n s u r e t h a t a d e q u a t e h e m o s t a s i s i s o b t a i n e d w i t h i n

t h e c e r e b e l l o p o n t i n e a n g l e . Fa t i s t a k e n f rom t h e

a b d o m e n a n d p l a c e d i n l o n g s t r i p s j u s t i n s i d e t h e

d u r a l o p e n i n g ; t h i s h a s b e e n f o u n d t o p r o v i d e a g o o d

s ea l a g a i n s t p o s t o p e r a t i v e c e r e b r o s p i n a l f luid l eak­

a g e . T h e l o n g ta i l s o f t h e s t r i p s a r e t h e n f o l d e d i n t o

t he m a s t o i d c a v i t v a n d a n t r u m , a n d t h e p o s t a u r i c u l a r

i n c i s i o n i s c l o s e d .

Intraoperative Complications or Problems

1 . S i g m o i d a n d s u p e r i o r p e t r o s a l s i n u s b l e e d i n g .

2 . J u g u l a r b u l b b l e e d i n g .

3 . F a c i a l n e r v e a v u l s i o n .

4 . V i t a l s i g n c h a n g e s .

Sinus Bleeding. B l e e d i n g a r i s i n g f r o m i n j u r y to t h e

s i n u s d u r i n g b o n e r e m o v a l m a y b e p r o f u s e a t t i m e s .

A l t h o u g h a l a r m i n g , w i t h p r o p e r m a n a g e m e n t i t m a y

b e c o n t r o l l e d w i t h o u t s e r i o u s c o n s e q u e n c e s . S i g m o i d

b l e e d i n g a r i s i n g f r o m e m i s s a r y v e i n s u s u a l l y c a n b e

c o n t r o l l e d b y full e x p o s u r e o f t h e v e i n a n d b i p o l a r

c a u t e r y ; p a c k i n g w i t h b o n e w a x o r S u r g i c e l i s a n o t h e r

o p t i o n . F o r t e a r s w i t h i n t h e s i n u s i t s e l f , p a c k i n g w i t h

S u r g i c e l wi l l c o n t r o l t h e i m m e d i a t e p r o b l e m o f b l o o d

l o s s ; h o w e v e r , i f b o n e r e m o v a l h a s b e e n c o m p l e t e d

t h e r e a r e n o b o n y l e d g e s a g a i n s t w h i c h t o w e d g e t h e

p a c k i n g . L a r g e p a c k s h i n d e r d i s s e c t i o n m o r e m e d i ­

a l ly ; i n a d d i t i o n , t h e p a c k s m a y b e c a u g h t i n t h e

dr i l l , c r e a t i n g a w h i p p i n g a c t i o n w i t h t h e S u r g i c e l .

O n e s o l u t i o n t o th i s i s t o c o v e r t h e p a c k i n g w i t h

b o n e w a x d r a p e d o v e r B i l l ' s i s l a n d ; a l o n g s t r i p o f

C o t t o n o i d i s t h e n d r a p e d o v e r t h e a r e a a n d t h e e n t i r e

c o m p l e x i s r e t r a c t e d w i t h t h e s u c t i o n i r r i g a t o r o r w i t h

a m a l l e a b l e r e t r a c t o r h o o k e d t o t h e c e r e b e l l a r r e t r a c ­

t o r s . A g a i n , b l e e d i n g u s u a l l y c a n b e c o n t r o l l e d ; t h e

o b j e c t i v e i s t o c o n t i n u e d i s s e c t i o n f a r t h e r m e d i a l l y

w i t h o u t h i n d r a n c e .

Jugular Bulb Bleeding. I n a d v e r t e n t i n j u r y to t h e

j u g u l a r b u l b i s s i g n a l e d b y p r o f u s e b l e e d i n g . P a c k i n g

i m m e d i a t e l y wi l l c o n t r o l t h e b l e e d i n g . C a u t i o n m u s t

b e e x e r c i s e d s i n c e t h e n i n t h , t e n t h , a n d e l e v e n t h

n e r v e s a r e i n t h i s a r e a a n d m a y b e i n j u r e d b y i n j u ­

d i c i o u s p a c k i n g . F o r s m a l l t e a r s i n t h e j u g u l a r b u l b ,

p a c k i n g m a y c o n t r o l t h e b l e e d i n g a n d a l l o w t h e

p r o c e d u r e t o c o n t i n u e . O n l y l a r g e p i e c e s o f p a c k i n g

m a t e r i a l a r e t o b e u s e d h e r e , i n o r d e r t o p r e v e n t

d i s p l a c e m e n t o f m a t e r i a l i n t o t h e l u m e n o f t h e v e i n

a n d a r e s u l t i n g p u l m o n a r y e m b o l u s ( t h i s i s a l s o a

c o n c e r n w i t h t e a r s i n t h e s i g m o i d ) . F o r l a r g e t e a r s , i t

i s o f t e n n e c e s s a r y a n d s a f e r t o tie t h e v e i n o f f i n t h e

n e c k b y e x t e n d i n g t h e p o s t a u r i c u l a r i n c i s i o n i n t e r i ­

o r ly ( fo r all n e u r o l o g i c p r o c e d u r e s t h e u p p e r n e c k i s

i n c l u d e d i n t h e d r a p i n g ) . T h e j u g u l a r b u l b i s t h e n

p a c k e d i n t r a l u m i n a l l y t o p r e v e n t b a c k - b l e e d i n g ,

Facial Nerw Avulsion. If t h e fac ia l n e r v e is l o s t or

a v u l s e d d u r i n g t u m o r r e m o v a l , a d e c i s i o n m u s t b e

m a d e w h e t h e r t o a t t e m p t i m m e d i a t e o r d e l a y e d re­

h a b i l i t a t i o n . B e c a u s e t h e b e s t a n d m o s t c o n s i s t e n t

r e s u l t s a r e o b t a i n e d f r o m i m m e d i a t e r e h a b i l i t a t i o n , i t

s h o u l d b e a t t e m p t e d i f p o s s i b l e . I f t h e b r a i n s t e m s i d e

o f t h e a v u l s e d n e r v e i s f o u n d a n d i s l o n g e n o u g h ,

t h e i n f r a t e m p o r a l p o r t i o n o f t h e fac ia l n e r v e m a y b e

m o b i l i z e d i n i ts e n t i r e t y f r o m i t s c a n a l . W i t h t h i s

m a n e u v e r , a n a d d i t i o n a l 1-cm l e n g t h o f n e r v e i s

o b t a i n e d ( b y p a s s i n g t h e l a b y r i n t h i n e a n d t e m p o r a l

c o u r s e o f t h e n e r v e ) a n d a n e n d - t o - e n d a n a s t o m o s i s

m a y be a t t e m p t e d . I f p o s s i b l e , a s u t u r e i s p l a c e d to

h o l d t h e a v u l s e d e n d s t o g e t h e r ( c o l l a g e n [ A v i t e n e j

h a s b e e n p l a c e d a r o u n d t h e t w o e n d s t o h o l d t h e m

in a p p o s i t i o n ) . I f t h i s i s n o t f e a s i b l e , a h y p o g l o s s a l -

facial n e r v e a n a s t o m o s i s i s p e r f o r m e d l a t e r .

Vital Sign Changes. V i t a l s i g n s a r e c o n s t a n t l y m o n ­

i t o r e d t h r o u g h o u t t u m o r r e m o v a l s u r g e r y . C o n t i n u ­

o u s c a r d i a c m o n i t o r i n g i s d o n e , a s w e l l a s m o n i t o r i n g

o f b l o o d p r e s s u r e w i t h a r t e r i a l l i n e s . W i t h a n y r ise

o r c h a n g e i n b l o o d p r e s s u r e o r p u l s e r e g u l a r i t y , t h e

s u r g e o n i s n o t i f i e d , t r a c t i o n i s s t o p p e d , a n d l a r g e

C o t t o n o i d p a c k i n g i s r e m o v e d i n o r d e r t o e l i m i n a t e

p r e s s u r e o n v e s s e l s . U s u a l l y r e s p o n s e s r e t u r n t o

n o r m a l i n a f e w m i n u t e s a n d s u r g e r y c o n t i n u e s , i t

t h e y r e c u r , a d e c i s i o n i s m a d e w h e t h e r t o c o n t i n u e

s u r g e r y b u t o n l y p e r f o r m a s u b t o t a l r e m o v a l ; i f t u m o r

i s left b e h i n d , i t m a y be r e m o v e d e l e c t i v e l y i n a b o u t

s ix m o n t h s . B y tha t t i m e t h e b r a i n s t e m c i r c u l a t i o n

h a s u s u a l l y i m p r o v e d f rom t u m o r d e b u l k i n g a n d

r e l e a s e o f p r e s s u r e , a n d t o t a l t u m o r r e m o v a l c a n b e

p e r f o r m e d s a f e l y . C o n s t a n t m o n i t o r i n g a n d r e p l a c e ­

m e n t o f b l o o d l o s s i s i m p o r t a n t t o p r e v e n t e a r l v s i g n s

o f s h o c k ( i n c r e a s e d p u l s e , d e c r e a s e d B P ) f r o m o f f s e t ­

t i n g t h e e f f e c t o f v e s s e l t r a c t i o n o r s p a s m ( d e c r e a s e d p u l s e , i n c r e a s e d B P ) .

Pertinent Histopathology

F I G U R E 1 9 - 7

T h i s h o r i z o n t a l s e c t i o n o f a t e m p o r a l b o n e s h o w ?

t h e p r e s e n c e o f a n a c o u s t i c n e u r o m a .

CHAPTER 20

Plastic Surgery of the Pinna

T h e p i n n a , o r a u r i c l e , i s t h e p r o j e c t i n g p a r t o f t h e

e a r t h a t l i e s o u t s i d e t h e h e a d ; i t s b a s i c a n a t o m y i s

s h o w n i n F i g u r e 2 0 - 1 . I t c o n s i s t s o f t w o t y p e s o f

t i s s u e : e l a s t i c ( y e l l o w ) c a r t i l a g e a n d , i n t h e e a r l o b e ,

f i b r o a r e o l a r t i s s u e . I t i s c o n n e c t e d t o t h e h e a d a n d

s c a l p b y t h e s u p e r i o r , a n t e r i o r , a n d p o s t e r i o r au r i ­

c u l a r m u s c l e s . B l o o d i s s u p p l i e d t o t h e p i n n a b y

b r a n c h e s o f t h e s u p e r f i c i a l t e m p o r a l a n d p o s t e r i o r

a u r i c u l a r a r t e r i e s , a n d i t i s i n n e r v a t e d b y b r a n c h e s o f

t h e g r e a t e r a u r i c u l a r a n d a u r i c u l o t e m p o r a l n e r v e s ,

t h e m a s t o i d b r a n c h o f t h e l e s s e r o c c i p i t a l n e r v e , a n d

a s m a l l b r a n c h o f t h e v a g u s n e r v e i n t h e c o n c h a

b o w l . T h i s c h a p t e r d e s c r i b e s s e v e r a l s u r g i c a l p r o c e ­

d u r e s for r e p a i r a n d r e c o n s t r u c t i o n o f t h e p i n n a .

Treatment of the Cleft Ear Lobe

P a t i e n t s a r e o f t e n s e e n i n t h e c l i n i c w i t h c le f t e a r

l o b e s s e c o n d a r y t o t r a u m a f r o m p i e r c i n g t h e e a r for

e a r r i n g s . T h e y m o s t o f t e n p r e s e n t w i t h a h e a l e d c le f t ,

bu t o c c a s i o n a l l y w i t h a " f r e s h " o r i n c o m p l e t e c le f t ;

v e r y r a r e l y a c o n g e n i t a l c lef t i s s e e n . R e g a r d l e s s o f

the p r e s e n t a t i o n , t h e t r e a t m e n t i s t h e s a m e

Aim

To c o r r e c t a c lef t e a r l o b e d e f e c t

Highlights

1 . M a k e a Z - p l a s t y o r V - p l a s t y a t t h e f ree m a r g i n

t o p r e v e n t p o s t o p e r a t i v e n o t c h i n g .

2 . D o n o t u s e a p o s t - t y p e e a r r i n g t o m a i n t a i n t he

e a r r i n g h o l e a f t e r t h e r e p a i r ; e v e n a l i g h t w e i g h t

e a r r i n g wi l l e n l a r g e t h e h o l e p o s t o p e r a t i v e l y .

Pitfalls

1. F a i l i n g to p e r f o r m a Z - p l a s t y o f t e n r e s u l t s in a

n o t c h a t t h e f r e e m a r g i n o f t h e l o b e a n d a d e p r e s s e d

s c a r .

2 . I f t h e p a t i e n t w e a r s a n e a r r i n g t o o s o o n a f te r

t he r e p a i r , a n e n l a r g e d e a r r i n g h o l e wil l r e s u l t

Instruments

N o . 1 1 a n d N o . 1 5 s c a l p e l b l a d e s a n d h a n d l e s .

T w o s k i n h o o k s , e i t h e r s i n g l e o r d o u b l e h o o k t y p e .

0 . 5 - m m o p h t h a l m i c f o r c e p s .

F i n e S t o r z " s t i t c h " s c i s s o r s .

S u t u r e s : 5 - 0 V i c r y l o n a c u t t i n g n e e d l e , 6 - 0 c h r o m i c

o r 6 - 0 n y l o n on a s m a l l c u t t i n g n e e d l e , 0 p r o l e n e

o r n y l o n

340 P l a s t i c S u r g e r y o f t h e P i n n a

Ant. auricular muscle

P l a s t i c S u r g e r y o f t h e P i n n a 3 4 1

Procedure

L i d o c a i n e 1 t o 2 % w i t h 1 : 1 0 0 , 0 0 0 e p i n e p h r i n e i s

u s e d . F i r s t t h e e d g e s o f t h e c lef t a r e e x c i s e d - I f t h e

c lef t i s n o t q u i t e c o m p l e t e , t h e s m a l l b r i d g e o f s k i n

a l s o i s e x c i s e d . A Z - p l a s t y i s f a s h i o n e d a n t e r i o r l y

( F i g . 20-2-A-C). O n e c a n a l s o b e m a d e p o s t e r i o r l y ,

b u t t h i s i s n o t n e c e s s a r y . A Z - p l a s t y s h o u l d a l s o b e

m a d e a t t h e f ree m a r g i n o f t h e l o b e t o p r e v e n t a

s m a l l n o t c h f r o m f o r m i n g d u r i n g t h e h e a l i n g p r o c e s s

A l t e r n a t i v e l y , t h e f ree m a r g i n c a n b e c l o s e d i n a " V "

t o n g u e - a n d - g r o o v e f a s h i o n . I f t h e p a t i e n t sti l l w i s h e s

to h a v e a p i e r c e d e a r , a l e n g t h of 0 p r o l e n e s u t u r e i s

f o r m e d i n t o a 1-in l o o p p a s s i n g t h r o u g h t h e f o r m e r

e a r r i n g s i t e . S o m e p a t i e n t s , n o t w i s h i n g t o h a v e t h e

l o o p o f s u t u r e i n t h e i r l o b e for s e v e r a l w e e k s , m a y

d e c i d e s i m p l y t o h a v e t h e e a r r e p i e r c e d a f te r t h e

r e p a i r h a s h e a l e d . T h e f i b r o a r e o l a r t i s s u e i s c l o s e d

w i t h i n t e r r u p t e d 5 - 0 V i c r y l a n d t h e s k i n i s c l o s e d

w i t h i n t e r r u p t e d 6 - 0 n y l o n o r 6 - 0 c h r o m i c s u t u r e s .

B a c i t r a c i n o i n t m e n t i s a p p l i e d t o t h e i n c i s i o n for a

f e w d a y s . 6 - 0 n y l o n s u t u r e s a r e r e m o v e d a t f o u r t o

f ive d a y s . I f 6 - 0 c h r o m i c s u t u r e s a r e u s e d , t h e p a t i e n t

c a n b e s e e n a t s e v e n t o 1 0 d a y s , a t w h i c h t i m e t h e

r e m a i n i n g w i s p s o f s u t u r e c a n b e g e n t l y w i p e d off .

A n e a r r i n g m a y b e w o r n a f te r f o u r w e e k s .

Treatment of Keloids

K e l o i d s a r e a c o m m o n p r o b l e m o f t h e e a r l o b e ,

e s p e c i a l l y i n b l a c k s . T h e y u s u a l l y i n v o l v e t h e m e d i a l

a s p e c t o f t h e l o b e , a n d m o s t o f t e n a r e t h e r e s u l t o f

d e e p d e r m a l i n j u r y t o t h e l o b e o f t h e e a r w h e n t h e

e a r s a r e p i e r c e d for e a r r i n g s . L a r g e l e s i o n s c a n b e

p a i n f u l w h e n h o l d i n g a t e l e p h o n e r e c e i v e r a g a i n s t

t h e e a r o r w h e n s l e e p i n g . A n y k e l o i d l a r g e e n o u g h

t o c a u s e a c o s m e t i c o r f u n c t i o n a l d e f e c t s h o u l d b e

e x c i s e d .

Aim

T o e x c i s e a n d p r e v e n t t h e r e c u r r e n c e o f t h e e a r

l o b e k e l o i d .

Highlights

1 . T h e k e y t o t r e a t m e n t i s t o p r e v e n t r e c u r r e n c e

a f te r e x c i s i o n . T h i s i s a c c o m p l i s h e d w i t h i n t r a l e s i o n a l

s t e r o i d i n j e c t i o n s a n d t h e u s e o f p r e s s u r e e a r r i n g s .

2 . S t a y a s c l o s e a s p o s s i b l e t o t h e s t a l k o f t h e

k e l o i d d u r i n g e x c i s i o n , i n o r d e r t o p r e s e r v e a s m u c h

n o r m a l s k i n o f t h e e a r l o b e a s p o s s i b l e .

Pitfalls

1 . R e p i e r c i n g o f t h e l o b e a f t e r s u c c e s s f u l t r e a t m e n t

o f a k e l o i d i s n o t r e c o m m e n d e d .

2 . F a i l i n g t o p r e v e n t a r e c u r r e n c e i s t h e m o s t

c o m m o n p r o b l e m a f t e r e x c i s i o n o f a k e l o i d . C l o s e

f o l l o w - u p a n d t h e u s e o f i n t r a l e s i o n a l s t e r o i d s a r e

t h e b e s t m e t h o d s o f p r e v e n t i n g a r e c u r r e n c e .

3 . T h e p a t i e n t w i t h l a r g e k e l o i d s m u s t b e a d v i s e d

t h a t t h e e a r l o b e m a y b e l e s s f l e s h y a f t e r e x c i s i o n o f

t h e k e l o i d ; t h a t o w i n g t o t h e m a s s o f t h e k e l o i d , l i t t l e

f i b r o f a t t y t i s s u e i s a v a i l a b l e for a d v a n c e m e n t i n t o t h e

w o u n d for c l o s u r e ; t h a t t h e l o b e m a y b e s m a l l e r a f t e r

e x c i s i o n o f t h e k e l o i d , o w i n g t o t h e e x c i s i o n o f s k i n

o n b o t h s u r f a c e s o f t h e l o b e ; a n d t h a t t h e l o b e m a y

b e r o t a t e d s l i g h t l y a n t e r i o r l y a f t e r t h e e x c i s i o n o f a

l a t e r a l k e l o i d a n d s l i g h t l y p o s t e r i o r l y a f t e r t h e e x c i ­

s i o n o f a m e d i a l k e l o i d .

Instruments

N o . 1 a n d N o . 1 5 s c a l p e l b l a d e s a n d h a n d l e s .

0 . 5 - m m o p h t h a l m i c f o r c e p s .

A f ine n e e d l e h o l d e r .

S t o r z " s t i t c h " s c i s s o r s .

S k i n h o o k s , e i t h e r s i n g l e o r d o u b l e .

S u t u r e s : 5 - 0 c h r o m i c o r V i c r y l , a n d 6 - 0 c h r o m i c o r 6 -

0 n y l o n on a s m a l l c u t t i n g n e e d l e .

Procedure

T h e t r e a t m e n t o f k e l o i d s i n v o l v e s t h r e e t r e a t m e n t

m o d a l i t i e s , s t e r o i d t h e r a p y , p r e s s u r e t h e r a p y , a n d

e x c i s i o n . T h e s e m o d a l i t i e s a r e o f t e n u s e d a t d i f f e r e n t

t i m e s i n t h e t r e a t m e n t o f t h e s a m e k e l o i d .

S m a l l k e l o i d s c a n b e t r e a t e d w i t h i n j e c t i o n s o f 4 0

m g p e r m l o f t r i a m c i n o l o n e a c e t o n i d e e v e r y f o u r t o

s ix w e e k s . T h e s t e r o i d c a n e i t h e r b e d e l i v e r e d w i t h a

D e r m a j e t a p p a r a t u s o r i n j e c t e d i n t o t h e d e r m i s w i t h

a 2 5 - o r 2 7 - g a u g e n e e d l e . A D e r m a j e t n e e d l e l e s s

i n j e c t o r d i s p e n s e s 0 .1 m l o f t h e s t e r o i d s o l u t i o n i n a

f ine d r o p l e t f o r m u n i f o r m l y i n t o t h e t i s s u e s ; t h i s

a v o i d s t h e b o l u s i n j e c t i o n o f s t e r o i d s t h a t c a n r e s u l t

f rom d i r e c t n e e d l e i n j e c t i o n i n t o d e n s e s c a r t i s s u e .

P l a s t i c S u r g e r y o f t h e P i n n a 3 4 3

O v e r z e a l o u s i n j e c t i o n c a n c a u s e s k i n a t r o p h y , t e l a n ­

g i e c t a s i s , a n d h y p o p i g m e n t a t i o n . I t m a y t a k e s ix t o

1 2 m o n t h s t o r e s o l v e t h e k e l o i d .

I t i s a l s o p o s s i b l e t o t r e a t s m a l l k e l o i d s w i t h p r e s ­

s u r e t h e r a p y . A p r e s s u r e - t y p e c l a s p e a r r i n g ( P a d g e t t

C o , K a n s a s C i t y , M O ) m a y s u p p l y e n o u g h p r e s s u r e

t o b l a n c h t h e c a p i l l a r i e s s u p p l y i n g t h e f i b r o u s t i s s u e

a n d c a u s e a r e g r e s s i o n o f t h e l e s i o n . I t m u s t b e w o r n

c o n t i n u o u s l y for s e v e r a l m o n t h s . W h e n t h e e a r r i n g

i s t a k e n o f f t h e k e l o i d c a n r e c u r ; t h e r e f o r e , i t i s

p r o b a b l y b e s t t o c o m b i n e u s e o f t h e p r e s s u r e e a r r i n g

w i t h m o n t h l y s t e r o i d i n j e c t i o n s .

F o r k e l o i d s t h a t a r e t o o l a r g e for p r e s s u r e t h e r a p y

o r t h a t d o n o t r e s p o n d t o s t e r o i d s , e x c i s i o n i s i n d i ­

c a t e d . T h e e n t i r e k e l o i d s h o u l d b e e x c i s e d . D e l i c a t e

h a n d l i n g i s n e c e s s a r y t o p r e v e n t t r a u m a t o t h e s u r ­

r o u n d i n g t i s s u e s . I f t h e k e l o i d i s e s p e c i a l l y l a r g e , i t

i s i m p o r t a n t t o f r e e u p s u r r o u n d i n g f i b r o f a t t y t i s s u e

t o fill i n t h e so f t t i s s u e d e f e c t . A W - p l a s t y o r Z - p l a s t y

i s u s e d t o c a m o u f l a g e t h e r e p a i r . S o m e t i m e s a s m a l l

r o t a t i o n a l f l a p m u s t b e u s e d for c l o s u r e . S t e r o i d s c a n

b e i n j e c t e d d i r e c t l y i n t o t h e s u r g i c a l s i t e a t t h e e n d

o f t h e p r o c e d u r e . 5 - 0 c h r o m i c o r V i c r y l i s u s e d for

d e e p s u t u r e s a n d 6 - 0 c h r o m i c o r n y l o n i s u s e d o n

the s k i n .

B a c i t r a c i n i s a p p l i e d for a f e w d a y s . N y l o n s u t u r e s

c a n b e r e m o v e d a f t e r f o u r t o f ive d a y s . W h e n e x c i s i o n

a l o n e i s u s e d t h e r e c u r r e n c e r a t e i s o v e r 5 0 v l ; t h e r e ­

fo re , t h e s u r g i c a l s i t e s h o u l d b e i n j e c t e d w i t h s t e r o i d s

e v e r y m o n t h for a p p r o x i m a t e l y s ix m o n t h s o r un t i l

t he s c a r i s m a t u r e . T o s t a b i l i z e t h e e a r k i b e w h e n

u s i n g t h e D e r m a j e t , i t i s h e l p f u l to p l a c e a t o n g u e

b l a d e a g a i n s t t h e l a t e r a l s u r f a c e o f t h e l o b e . A t t h e

first s i g n o f r e c u r r e n c e , a p r e s s u r e e a r r i n g s h o u l d b e

a d d e d t o t h e t r e a t m e n t r e g i m e n

Traumatic Injuries of the Pinna

I n j u r i e s o f t h e p i n n a a r e c l a s s i f i e d a s f o l l o w s :

1 . T r a u m a t i c h e m a t o m a w i t h o r w i t h o u t c e l l u l i t i s

o r p e r i c h o n d r i t i s

2 . L a c e r a t i o n w i t h o u t t i s s u e l o s s

3 . L a c e r a t i o n w i t h s k i n o r c a r t i l a g e l o s s , o r b o t h .

4 . T o t a l a m p u t a t i o n o f t h e p i n n a .

Hematoma of the Pinna

A h e m a t o m a o f t h e p i n n a i s c a u s e d b y b l u n t

t r a u m a a n d m o s t o f t e n a f f e c t s t h e l a t e ra l s u r f a c e ( F i g .

2 0 - 2 D ) . I t s h o u l d b e d r a i n e d a s s o o n a s p o s s i b l e

b e f o r e t h e c l o t o r g a n i z e s . A n o r g a n i z e d h e m a t o m a

r e q u i r e s m o r e e x t e n s i v e s u r g e r y .

Aim

T o d r a i n t h e h e m a t o m a , p r e v e n t r e a c c u m u l a t i o n ,

a v o i d s e c o n d a r y c e l l u l i t i s o r p e r i c h o n d r i t i s , a n d p r e ­

v e n t t h e d e f o r m i t y c a u s e d b y o r g a n i z a t i o n o f t h e

h e m a t o m a ( c a u l i f l o w e r e a r ) .

Highlights

1 . T h e m o s t i m p o r t a n t s t e p i s t h e p l a c e m e n t o f a

w e l l - m o l d e d d r e s s i n g t o p r e v e n t a r e c u r r e n c e

2 . T h e i n c i s i o n s h o u l d b e h i d d e n o r s h o u l d r u n

f a v o r a b l y w i t h t h e a n a t o m y o f t h e p i n n a .

3 . A d r a i n m a y b e n e c e s s a r y w h e n t r e a t i n g a l a r g e

h e m a t o m a .

Pitfalls

1 . R e c u r r e n c e o f t h e h e m a t o m a o w i n g t o a n in­

a d e q u a t e d r e s s i n g .

Instruments and Supplies

N o . 1 1 o r N o . 1 5 s c a l p e l a n d h a n d l e .

C u r v e d h e m o s t a t ( m o s q u i t o )

0 . 2 5 - i n P e n r o s e d r a i n ( o p t i o n a l )

C o t t o n b a l l s .

P o v i d o n e - i o d i n e ( B e t a d i n e ) o i n t m e n t

5 0 - 5 0 m i x t u r e o f m i n e r a l oil a n d B e t a d i n e s o l u t i o n

( o p t i o n a l ) .

4 x 4 " F l u f f s . "

2- in r o l l e d b a n d a g e s

2 - 0 n y l o n o r p r o l e n e o n a l a r g e c u t t i n g n e e d l e

H i b i c l e n s o r B e t a d i n e s c r u b .

N o r m a l s a l i n e i r r i g a t i n g s o l u t i o n .

Procedure

L i d o c a i n e 1 % w i t h 1 : 1 0 0 , 0 0 0 e p i n e p h r i n e c a n b e

u s e d a s a f ie ld b l o c k o r i n j e c t e d l o c a l l y . T h e e a r i s

p r e p a r e d w i t h H i b i c l e n s o r B e t a d i n e s c r u b . A v e r t i c a l

c u r v i l i n e a r i n c i s i o n i s m a d e o v e r o r a l o n g t h e s i d e o f

t h e h e m a t o m a ( u s u a l l y u n d e r e i t h e r t h e h e l i c a l o r

a n t h e l i c a l fo ld t o c a m o u f l a g e i t ) . I t i s b e t t e r t o m a k e

a n i n c i s i o n l a r g e e n o u g h for g o o d d r a i n a g e a n d d e a l

w i t h t h e r e s u l t a n t s c a r l a t e r t h a n t o b e f a c e d w i t h a

p e r s i s t e n t o r r e c u r r e n t h e m a t o m a a n d s e c o n d a r y

p e r i c h o n d r i t i s . A c u r v e d m o s q u i t o h e m o s t a t m a y b e

u s e d t o o p e n u p a n y l o c u l a t i o n s . A c u l t u r e o f t h e

h e m a t o m a s h o u l d b e t a k e n i f c e l l u l i t i s i s p r e s e n t .

344 P i a s i i c S u r g e r y o f t h e P i n n a

T h e h e m a t o m a c a n t h e n b e i r r i g a t e d g e n t l y w i t h

s t e r i l e n o r m a l s a l i n e . A >/i-in P e n r o s e d r a i n o r r u b b e r

b a n d d r a i n s h o u l d b e u s e d for e x t e n s i v e h e m a t o m a s .

S k i n s u t u r e s s h o u l d t h e n a p p r o x i m a t e t h e s k i n o f

l a r g e i n c i s i o n s b u t s t i l l a l l o w a d e q u a t e d r a i n a g e . N e x t

c o t t o n b a l l s s a t u r a t e d w i t h B e t a d i n e o i n t m e n t ( o r a

5 0 - 5 0 m i x t u r e o f B e t a d i n e s o l u t i o n a n d m i n e r a l o i l )

a r e f o r m e d i n t o s h a p e s t h a t p r e c i s e l y c o r r e s p o n d t o

t h e f o l d s o f t h e p i n n a o v e r l y i n g t h e h e m a t o m a . A n

a d d i t i o n a l p i e c e o f c o t t o n s h o u l d b e m o l d e d t o fit

i n t o t h e p o s t a u r i c u l a r c r e a s e ( F i g . 2 0 - 2 E ) . A n e x a c t

fit i s n e c e s s a r y t o p r e v e n t r e a c c u m u l a t i o n o f t h e

h e m a t o m a s . T h e p i e c e s o f c o t t o n a r e h e l d i n p l a c e

w i t h t h r o u g h - a n d - t h r o u g h 2 - 0 n y l o n o r p r o l e n e m a t ­

t r e s s s u t u r e s ; u s u a l l y t w o w i l l s u f f i c e . A m a s t o i d

d r e s s i n g o f " F l u f f s " a n d a 2 - in r o l l e d b a n d a g e a r e

t h e n a p p l i e d .

Postoperat ive Care

T h e p a t i e n t s h o u l d b e p l a c e d o n a n o ra l a n t i b i o t i c

t h a t c o v e r s for s k i n f l o r a , p r e d o m i n a n t l y Slnp/n/locot'-

cus . T h e m a s t o i d d r e s s i n g a n d c o t t o n b a l l s c a n b e

r e m o v e d a f t e r t w o d a y s a n d t h e p i n n a i n s p e c t e d . I f

t h e r e h a s b e e n n o r e a c c u m u l a t i o n , n o f u r t h e r m a s t o i d

d r e s s i n g i s n e e d e d a n d t h e c o t t o n b o l s t e r s a r e re­

m o v e d i n t w o t o t h r e e d a y s . I f r e a c c u m u l a t i o n h a s

o c c u r r e d , t h e h e m a t o m a m u s t b e d r a i n e d a g a i n , a n d

t h e s a m e t y p e o f p r e c i s e c o t t o n p a c k i n g w i t h n

m a s t o i d d r e s s i n g i s r e a p p l i e d . I f t h e r e i s e v i d e n c e o f

p e r i c h o n d r i t i s , c u l t u r e s s h o u l d b e t a k e n a n d p a r e n ­

t e ra l a n t i b i o t i c s s t a r t e d . A P e n r o s e d r a i n o r a

t h r o u g h - a n d - t h r o u g h s u c t i o n i r r i g a t i o n s y s t e m m a v

b e n e c e s s a r v . I f t h e r e i s e v i d e n c e o f c a r t i l a g e n e c r o s i s ,

w i d e d e b r i d e m e n t o f n e c r o t i c sof t t i s s u e a n d c a r t i l a g e

i s n e e d e d . T h e r e c o n s t r u c t i o n o f a n y d e f e c t s r e s u l t i n g

f r o m p e r i c h o n d r i t i s i s s i m i l a r t o t h a t p e r f o r m e d a f t e r

n e o p l a s m r e s e c t i o n ( d e s c r i b e d b e l o w ) .

Laceration without Tissue Loss

T h e e a r ' s p r o m i n e n t a n d e x p o s e d l o c a t i o n o n t h e

h e a d r e n d e r s i t v u l n e r a b l e t o l a c e r a t i o n s . C o m p l e x

l a c e r a t i o n s s h o u l d b e c a r e f u l l y e x a m i n e d fo r f o r e i g n

b o d i e s a n d a n y e v i d e n c e o f so f t t i s s u e l o s s . T h e s k i n

i s d e n s e l y a d h e r e n t t o t h e u n d e r l y i n g c a r t i l a g e , a n d

a n y f u l l - t h i c k n e s s i n j u r y o f t h e d e r m i s wil l e x p o s e

t h e c a r t i l a g e t o t h e r i s k o f i n f e c t i o n . Al l f u l l - t h i c k n e s s

l a c e r a t i o n s s h o u l d b e r e p a i r e d .

Aim

T o r e p a i r a l a c e r a t i o n o f t h e p i n n a .

Highlights

1 . I n t r a c a r t i l a g i n o u s s u t u r e s a r e o f t e n n e c e s s a r y .

2 . A p p a r e n t l y n o n v i t a l t i s s u e s h o u l d b e s a v e d

w h e n e v e r p o s s i b l e . If a c u t a n e o u s l i n k o f s k i n per­

s i s t s , t h e s k i n o f t h e p i n n a h a s a r e m a r k a b l e a b t l i t . 1

t o w i t h s t a n d v a s c u l a r c o m p r o m i s e . T h e n o n v i t a l t i s ­

s u e wi l l d e m a r c a t e s e v e r a l d a y s l a t e r a n d c a n b e

d e b r i d e d t h e n .

3 . U s e o f a s t e n t w i t h e x t e r n a l a u d i t o r y c a n a l

l a c e r a t i o n s t o p r e v e n t s t e n o s i s .

Pitfalls

1 . P o s t - t r a u m a t i c t a t t o o i n g d u e t o i n c o m p l e t e d e ­

b r i d e m e n t .

2 . I m p r e c i s e c l o s u r e r e s u l t i n g i n p r o m i n e n t s c a r ­

r i n g o r i r r e g u l a r i t i e s i n t h e c a r t i l a g e f o r m a t i o n .

3 . F a i l i n g t o r e c o g n i z e a n e x t e r n a l a u d i t o r y c a n a l

l a c e r a t i o n .

Instruments

A b a s i c p l a s t i c s p a c k .

Procedure

U s u a l l y 17, l i d o c a i n e w i t h 1 : 1 0 0 , 0 0 0 e p i n e p h r i n e

c a n b e u s e d . I f t h e r e a r e f l a p s o r r e g i o n s w i t h a

c o m p r o m i s e d b l o o d s u p p l y , 1V< l i d o c a i n e w i t h o u t

e p i n e p h r i n e s h o u l d b e u s e d . S i m p l e l a c e r a t i o n s o l

t h e s k i n o f t h e p i n n a s h o u l d b e m e t i c u l o u s l y c l e a n e d .

I t i s i m p o r t a n t t o r e m o v e all d e b r i s t o p r e v e n t p o s t ­

t r a u m a t i c t a t t o o i n g . T h e l a c e r a t i o n s h o u l d b e c l o s e d

w i t h 6 - 0 c h r o m i c o r 6 - 0 n y l o n s u t u r e . I f n e c e s s a r y ,

s u b c u t a n e o u s s u t u r e s a l s o a r e u s e d t o r e d u c e t e n s i o n

a n d e v e r t t h e s k i n e d g e s ; 5 - 0 V i c r v l o r c h r o m i c

. su tu r e s w o r k b e s t for t h i s ( F i g . 2 0 - 21, C). S u t u r e s o l

6 - 0 c h r o m i c a r e p l a c e d t h r o u g h t h e s k i n d i f f e r e n t l y

f r o m 6 - 0 n y l o n s u t u r e s . C h r o m i c s u t u r e s u s u a l l y a r e

n o t r e m o v e d a n d o n l y s e r v e t o a p p r o x i m a t e t h e s k i n

e d g e s , r a t h e r t h a n d r a w i n g t h r o u g h t h e s u b c u t a ­

n e o u s t i s s u e ; t h e y a r e i n d i c a t e d w h e n t h e r e i s n o

t e n s i o n o n t h e w o u n d e d g e s . E i t h e r r u n n i n g l o c k e d

s u t u r e s o r s i m p l e i n t e r r u p t e d s u t u r e s c a n b e u s e d .

L a c e r a t i o n s i n v o l v i n g c a r t i l a g e c a n b e c l o s e d b y

d i r e c t l y s u t u r i n g t h e c a r t i l a g e t o g e t h e r w i t h 5 - 0 Vi ­

c r y l . U n l e s s t h e c a r t i l a g e i s g r o s s l y c o n t a m i n a t e d i t

d o e s n o t n e e d d e b r i d i n g . H o r i z o n t a l m a t t r e s s s u t u r e s

i n t h e p l a n e o f t h e c a r t i l a g e p r o v i d e a c c u r a t e r e a p -

p r o x i m a t i o n .

L a c e r a t i o n s t h r o u g h t h e e x t e r n a l a u d i t o r y c a n a l

a r e t r e a t e d i n i t i a l l y w i t h a b a c i t r a c i n g a u z e p a c k . T h e

p a c k c a n b e r e m o v e d i n f ive t o s e v e n d a y s , a t w h i c h

P l a s t i c S u r g e r y o f t h e P i n n a 345

t i m e a s t e n t m u c h l i ke t h a t for a h e a r i n g a id c a n be

p l a c e d t o p r e v e n t p o s t - t r a u m a t i c s t e n o s i s o f t h e c a n a l

(F ig 2 0 - 2 H ) . A c e n t r a l h o l e s h o u l d b e d r i l l e d t o a l l o w

h e a r i n g . T h e s t e n t s h o u l d b e w o r n fo r t h r e e t o s ix

w e e k s , d e p e n d i n g o n t h e s e v e r i t y o f t h e i n j u r y

B a c i t r a c i n i s a p p l i e d t o t h e l a c e r a t i o n t o p r e v e n t

c r u s t i n g . I f t h e l a c e r a t i o n i s e x t e n s i v e , a m a s t o i d

d r e s s i n g w i t h c o t t o n m o l d i n g ( l i k e t h a t u s e d for

p i n n a h e m a t o m a s b u t w i t h o u t t h e m a t t r e s s s t a y

s u t u r e s ) s h o u l d b e a p p l i e d a n d w o r n for t w o t o t h r e e

d a y s .

Laceration with Skin or Cartilage Loss

R e c o n s t r u c t i o n o f t h e p i n n a a f te r l a c e r a t i o n s w i t h

t i s s u e l o s s i s s i m i l a r t o t h a t a f t e r t h e r e s e c t i o n o f a

n e o p l a s m ( d e s c r i b e d b e l o w ) .

Total Amputation of the Pinna

F o r t u n a t e l y , t o t a l o r s u b t o t a l a m p u t a t i o n o f t h e

p i n n a i s a r a r e o c c u r r e n c e . C a s e s i n w h i c h t h e a m ­

p u t a t e d p i e c e i s m i s s i n g o r g r o s s l y c o n t a m i n a t e d

o b v i a t e t h e n e e d for i m m e d i a t e r e c o n s t r u c t i o n . D e ­

l a y e d t o t a l a u r i c u l a r r e c o n s t r u c t i o n o r p r o s t h e t i c r e ­

h a b i l i t a t i o n a r e o u t s i d e t h e s c o p e o f t h i s t e x t . W h e n

l e s s t h a n 5 0 % o f t h e t i s s u e o f t h e p i n n a h a s b e e n

l o s t , a n d t h e a m p u t a t e d p a r t h a s b e e n s a v e d , r e c o n ­

s t r u c t i o n o f t h e r e m n a n t i s s i m i l a r t o t h a t p e r f o r m e d

a f t e r n e o p l a s m r e s e c t i o n .

Aim

T o r e a t t a c h t h e a m p u t a t e d p o r t i o n o f t h e p i n n a

H i g h l i g h t s

1 . I f t h e a m p u t a t e d p i e c e i s a v a i l a b l e , r e i m p l a n ­

t a t i o n s h o u l d b e a t t e m p t e d u n l e s s t h e p a t i e n t ' s m e d ­

ica l c o n d i t i o n c o n t r a i n d i c a t e s a l e n g t h y g e n e r a l a n ­

e s t h e t i c .

2 . C l o s e p o s t o p e r a t i v e f o l l o w - u p i s n e e d e d t o

w a t c h for i n f e c t i o n , v e n o u s c o n g e s t i o n , a n d n e c r o s i s .

Pitfalls

1 . T h e l a r g e r t h e a m p u t a t e d p a r t , t h e g r e a t e r i s

t h e l i k e l i h o o d o f p a r t i a l o r to ta l l o s s .

2 . V e n o u s c o n g e s t i o n m a y n o t b e p r e v e n t a b l e

e v e n w i t h p i e - c r u s t i n c i s i o n s o r l e e c h e s .

3 . T h e c a r t i l a g e s k e l e t o n wi l l n o t b e a s s h a r p o r

w e l l - d e f i n e d w h e n r e - e p i t h e l i a l i z e d w i t h t h e t h i c k e r

p o s t a u r i c u l a r s k i n .

Ins t ruments

A b a s i c p l a s t i c p a c k p l u s a d e r m a b r a d e r .

M i c r o v a s c u l a r i n s t r u m e n t s .

Procedure

G e n e r a l a n e s t h e s i a u s u a l l y i s i n d i c a t e d o w i n g t o

t h e l e n g t h o f t h e r e p a i r . W h e n t h e a m p u t a t e d p a r t i s

a v a i l a b l e i t s h o u l d b e r i n s e d i n c o l d s a l i n e , w r a p p e d

i n a m o i s t c o t * o n g a u z e , p l a c e d i n a s e a l a b l e p l a s t i c

b a g , a n d t h e n p a c k e d i n i c e . W h e n d e a l i n g w i t h a n

a m p u t a t e d p i n n a , i t i s i m p o r t a n t t o let t h e p a t i e n t

a n d f a m i l y k n o w t h e p o o r p r o g n o s i s e v e n i n t h e b e s t

o f c i r c u m s t a n c e s .

I n c l e a n a m p u t a t i o n s w i t h o u t m u c h c r u s h i n g o r

a v u l s i o n o f t i s s u e , m i c r o v a s c u l a r r e a t t a c h m e n t o f a n

a m p u t a t e d p i n n a m a y b e i n d i c a t e d . I f t h i s s e r v i c e i s

a v a i l a b l e i t i s p r o b a b l y a w o r t h w h i l e e f f o r t .

I f o n l y a s m a l l p i e c e (1 t o 2 cm o f t i s s u e o r t h e

h e l i c a l r i m ) h a s b e e n a m p u t a t e d i t c a n s i m p l y b e

r e a t t a c h e d , b u t r e a t t a c h m e n t o f a t o t a l l y a m p u t a t e d

p i n n a w i t h o u t r e - e s t a b l i s h m e n t o f t h e c i r c u l a t i o n b y

m i c r o v a s c u l a r s u r g e r y o f t e n r e s u l t s i n a t o t a l l o s s o f

t h e p i n n a s e c o n d a r y t o v a s c u l a r c o n g e s t i o n . H o w ­

e v e r , i f t h e r e i s a s m a l l c u t a n e o u s b r i d g e l i n k i n g t h e

p i n n a t o t h e h e a d , s i m p l e r e a t t a c h m e n t i s a d v a n t a ­

g e o u s . M e d i c i n a l l e e c h e s h a v e b e e n u s e d t o r e d u c e

t h e v e n o u s c o n g e s t i o n .

I n s o m e c a s e s , w h e n t h e p i n n a h a s b e e n t o t a l l y

a m p u t a t e d a n d m i c r o v a s c u l a r r e p a i r i s n o t a v a i l a b l e

o r i n d i c a t e d , t h e c a r t i l a g i n o u s f r a m e w o r k m a y b e

s a l v a g e d b y d e r m a b r a d i n g a l l o f t h e e p i d e r m i s f r o m

t h e c a r t i l a g i n o u s s k e l e t o n a n d b u r y i n g t h e p i n n a i n

a p o s t a u r i c u l a r p o c k e t for t h r e e t o f o u r w e e k s . T h e

c a r t i l a g i n o u s s k e l e t o n c a n t h e n b e " r e l e a s e d " f r o m

t h i s p o c k e t a n d a l l o w e d t o s l o w l y r e - e p i t h e l i a l i z e .

I f o n l y a p o r t i o n o f t h e p i n n a h a s b e e n a m p u t a t e d ,

all o f t h e so f t t i s s u e o v e r l y i n g b o t h s u r f a c e s o f t h e

a m p u t a t e d s e g m e n t i s r e m o v e d , s p a r i n g t h e p e r i ­

c h o n d r i u m ; t h e c a r t i l a g e s e g m e n t i s t h e n r e a t t a c h e d

t o t h e r e m a i n i n g p i n n a w i t h m a t t r e s s s u t u r e s t o

r e a p p r o x i m a t e t h e c a r t i l a g e . T h e d e n u d e d c a r t i l a g e

s e g m e n t i s t h e n b u r i e d i n a p o s t a u r i c u l a r p o c k e t ,

w h i c h h a s b e e n c r e a t e d b y i n c i s i n g t h e p o s t a u r i c u l a r

s k i n , f o l l o w e d b y w i d e u n d e r m i n i n g ( F i g . 2 0 - 3 )

A n o t h e r m e t h o d o f s a l v a g i n g t h e c a r t i l a g i n o u s

s k e l e t o n o f t h e a m p u t a t e d e a r i s t o r e m o v e t h e s k i n

P l a s t i c S u r g e r y o f t h e P i n n a 347

f r o m t h e m e d i a l s u r f a c e o f t h e p i n n a a n d p e r f o r a t e

t i l e c a r t i l a g e . The p o s t a u r i c u l a r s k i n i s t h e n r e m o v e d

a n d t h e e a r i s r e a t t a c h e d b y s u t u r i n g t h e h e l i c a l r im

t o t h e f r e e m a r g i n o f r e m a i n i n g p o s t a u r i c u l a r s k i n

( F i g 2 0 - 4 ) . " P i e - c r u s t " i n c i s i o n s o r m e d i c i n a l l e e c h e s

m a y b e n e c e s s a r y i f v e n o u s c o n g e s t i o n i s a p r o b l e m .

T h e l a s t t w o m e t h o d s r e q u i r e t h a t t h e h e l i c a l r im

b e l i f ted a f t e r t h r e e t o f o u r w e e k s b y i n c i s i n g t h e

p o s t a u r i c u l a r s k i n . T h e d e f e c t left i n t h e p o s t a u r i c u l a r

a r e a c a n s o m e t i m e s b e c l o s e d b y p r i m a r y c l o s u r e . A

s p l i t - t h i c k n e s s o r f u l l - t h i c k n e s s s k i n gra f t f r o m t h e

o p p o s i t e p o s t a u r i c u l a r r e g i o n o r f r o m t h e s u p r a c l a ­

v i c u l a r a r e a a l s o c a n b e u s e d . A n o t h e r m e t h o d i s t o

p l a c e a f o s s a t i s s u e e x p a n d e r b e h i n d t h e ea r , a n d t o

u s e t h i s e x p a n d e d s k i n t o r e s t i r f a c e t h e p o s t a u r i c u l a r

a r e a .

I f t h e p o s t a u r i c u l a r a r e a i s b a d l y i n j u r e d a n d n o t

s u i t a b l e for o n e o f t h e a b o v e m e t h o d s o f r e c o n s t r u c ­

t i o n , t h e p i n n a c a n b e " b a n k e d " u n d e r c e r v i c a l s k i n

T h i s i s d o n e b y r e m o v i n g t h e so f t t i s s u e f r o m t h e

c a r t i l a g e ; m a k i n g a p o c k e t u n d e r a c e r v i c a l s k i n f l ap ,

a n d l e a v i n g i t t h e r e u n t i l t h e p o s t a u r i c u l a r s k i n h a s

h e a l e d . A c r e s c e n t - s h a p e d t i s s u e e x p a n d e r c a n t h e n

b e p l a c e d i n t h e p o s t a u r i c u l a r / m a s t o i d r e g i o n a n d

s l o w l y e x p a n d e d o v e r f o u r t o s ix w e e k s un t i l t w i c e

a s m u c h s u r f a c e a r e a i s e x p a n d e d ( s e c F ig . 2 0 - 4 / 3 ) .

T h e " b a n k e d " c a r t i l a g e s k e l e t o n i s r e m o v e d f r o m

b e n e a t h t h e c e r v i c a l f l a p a n d p l a c e d i n t o t h e e x ­

p a n d e d p o c k e t . H i g h - v a c u u m s u c t i o n i s n e c e s s a r y t o

o b t a i n g o o d a p p o s i t i o n o f t h e s k i n t o t h e i n t e r s t i c e s

o f t h e c a r t i l a g e .

Postoperative Care

S t e r o i d s , h e p a r i n , a n t i b i o t i c s , p i e - c r u s t i n c i s i o n s

a n d , l a t e l y , m e d i c i n a l l e e c h e s h a v e all b e e n a d v o ­

c a t e d i n t h e c a r e o f t h e r e i m p l a n t e d p i n n a . M e t i c u ­

l o u s w o u n d c a r e w i t h b a c i t r a c i n a n d A d a p t i c g a u z e

i s n e c e s s a r y . O f t e n t h e r e i s d e - e p i t h e l i a l i z a t i o n o f t h e

a m p u t a t e d p a r t , b u t w i t h g e n t l e d e b r i d e m e n t t h e

p i n n a u s u a l l v c a n r e - e p i t h e l i a l i z e . I f t h e r e i m p l a n t a ­

t i o n i s s u c c e s s f u l , t h e p a t i e n t m u s t b e c a u t i o n e d t h a t

t h e n e w c i r c u l a t i o n m a y n o t b e r e s i l i e n t e n o u g h t o

b e i m m e d i a t e l y e x p o s e d t o e x t r e m e s o f t e m p e r a t u r e

o r i n j u d i c i o u s l y e x p o s e d t o t h e s u n .

Neoplasms of the Pinna

T h e p i n n a i s a f r e q u e n t s i t e o f b a s a l ce l l a n d

s q u a m o u s ce l l c a r c i n o m a s a n d , l e s s f r e q u e n t l y , m a ­

l i g n a n t m e l a n o m a s . Al l b u t s h a v e d , p u n c h e d , o r

c u r e t t e d b i o p s i e s s h o u l d b e r e p a i r e d . T h e t e c h n i q u e s

u s e d t o r e c o n s t r u c t d e f e c t s o f t h e p i n n a a f t e r r e s e c ­

t i on o f a n e o p l a s m c a n a l s o b e u s e d t o r e c o n s t r u c t

t h e p i n n a a f t e r a l a c e r a t i o n w i t h t i s s u e l o s s

Aim

T o r e c o n s t r u c t t h e p i n n a a f t e r r e s e c t i o n o f a n e o ­

p l a s m .

Highlights

1 . G e n t l e h a n d l i n g o f t h e t i s s u e s i s n e c e s s a r y t o

r e d u c e o p e r a t i v e t r a u m a .

2 . S m a l l d e f e c t s a r e r e p a i r e d b y p r i m a r y c l o s u r e

o r c o m p o s i t e g ra f t .

3 . L a r g e r d e f e c t s m o s t o f t e n a r e r e p a i r e d w i t h a

p o s t a u r i c u l a r p e d i c l e d g r a f t .

4 . T h e l e s s c o m p l e x t h e r e p a i r , t h e g r e a t e r i s t h e

l i k e l i h o o d o f g o o d r e s u l t s .

5 . Al l m a r g i n s o f r e s e c t i o n s h o u l d b e h i s t o l o g i c a l l y

e x a m i n e d .

Pitfalls

1 . I m p r e c i s e c l o s u r e m a v l e a d to a c o s m e t i c d e f o r ­

m i t y .

2 . A c o m p o s i t e g ra f t m a y be los t i f i t i s t o o l a r g e

( > 1.5 c m ) .

3 . A p i n n a m a y " c u p " a f t e r a w e d g e r e s e c t i o n i f

w e d g e s o f s k i n a n d c a r t i l a g e a r e n o t r e m o v e d a l o n g

t h e a n t h e l i c a l f o ld .

Instruments

T h e i n s t r u m e n t s l i s t e d b e l o w f o r m t h e b a s i c s o f a

p l a s t i c s t r a y u s e d for m o s t so f t t i s s u e s u r g e r y o f t h e

h e a d a n d n e c k . T h e s e i n s t r u m e n t s wil l b e u s e d for

t h e p r o c e d u r e s d e s c r i b e d i n t h e res t o f t h i s c h a p t e r .

N o . 1 1 a n d N o 1 5 s c a l p e l b l a d e s a n d h a n d l e s

M e d i u m a n d f i n e n e e d l e h o l d e r s .

0 . 5 - m m o p h t n a l m i c f o r c e p s

B r o w n - A d s o n f o r c e p s .

N o . 3 s i n g l e o r d o u b l e s k i n h o o k s .

N o . 2 S e n n r e t r a c t o r s .

S t o r z " s t i t c h " s c i s s o r s .

H C U R K 2 < M

P l a s t i c S u r g e r y o f t h e P i n n a 349

C u r v e d a n d s t r a i g h t ir is s c i s s o r s .

S m a l l M e t z e n b a u m s c i s s o r s

T e n o t o m y s c i s s o r s

S u t u r e s : 4 - 0 a n d 5 - 0 V i c r y l , 4 - 0 a n d 6 - 0 n y l o n , 6 - 0

c h r o m i c .

M a r k i n g p e n .

C o t t o n - t i p p e d a p p l i c a t o r s .

D r e s s i n g : T i n c t u r e o f b e n z o i n , S t e r i - S t r i p s , 4 x 4

" F l u f f s , " 2 - i n r o l l e d b a n d a g e , c o t t o n b a l l s , a n d

B e t a d i n e o i n t m e n t .

Procedure

D e p e n d i n g o n t h e e x t e n t o f t h e r e c o n s t r u c t i o n ,

e i t h e r l o c a l a n e t h e s i a w i t h 1 % l i d o c a i n e a n d 1 : 1 0 0 , 0 0 0

e p i n e p h r i n e o r g e n e r a l a n e s t h e s i a c a n b e u s e d

A f t e r t h e r e s e c t i o n o f a n e o p l a s m , t h e p i n n a c a n

b e r e c o n s t r u c t e d b y m a n y m e t h o d s , l i m i t e d o n l y b y

t h e s u r g e o n ' s i m a g i n a t i o n a n d i n g e n u i t y . T h e f o l l o w ­

i n g d i s c u s s i o n , w h i c h i s n o t i n t e n d e d t o b e e n c y ­

c l o p e d i c , o u t l i n e s m e t h o d s t h a t h a v e w o r k e d we l l

o v e r t h e y e a r s a n d t h a t a r e b a s e d o n g e n e r a l p r i n c i ­

p l e s o f f l ap d e s i g n .

A f t e r r e m o v i n g t h e n e o p l a s m , all m a r g i n s m u s t

b e e x a m i n e d h i s t o l o g i c a l l y .

T h e p i n n a c a n b e r e c o n s t r u c t e d i n t h r e e w a v s : (1 )

p r i m a r y c l o s u r e , ( 2 ) a c o m p o s i t e g ra f t f r o m t h e o t h e r

e a r , a n d ( 3 ) a p e d i c l e d s k i n / c a r t i l a g e f l a p .

Prunaru Closure. W h e n l e s s t h a n 307r o f t h e p i n n a

h a s b e e n e x c i s e d , t h e d e f e c t o f t e n c a n b e c l o s e d

p r i m a r i l y , e s p e c i a l l y i t i t i n v o l v e s t h e u p p e r a n d

m i d d l e p o r t i o n s o f t h e p i n n a ( F i g . 2 0 - 5 / 1 . B). W h e n

c l o s i n g a d e f e c t p r i m a r i l y , i t i s u s u a l l y n e c e s s a r y to

u s e a n v o f a v a r i e t y o f r e l e a s i n g i n c i s i o n s a l o n g t h e

a n t h e l i c a t fo ld a n d c o n c h a l b o w l t o a l l o w for t h e

a d v a n c e m e n t o f a d j a c e n t t i s s u e . T h e r ig id c a r t i l a g i ­

n o u s f r a m e w o r k o f t h e p i n n a , t h e d e n s e l y a d h e r e n t

s k i n , a n d t h e l a c k o f s u b c u t a n e o u s t i s s u e h i n d e r t h e

c l o s u r e o f e v e n s m a l l d e f e c t s . W i t h o u t t h e s e i n c i ­

s i o n s , c l o s u r e o f t h e d e f e c t m a y c a u s e c u p p i n g o f t h e

p i n n a . O f t e n , s m a l l w e d g e s o f c o n c h a l b o w l c a r t i l a g e

m u s t b e r e m o v e d s o t h a t p r o p e r c l o s u r e c a n b e

o b t a i n e d . C l o s u r e i s a c c o m p l i s h e d w i t h i n t e r r u p t e d

5-0 V i c r y l s u t u r e i n t h e c a r t i l a g e a n d a c u t a n e o u s

l a y e r o f r u n n i n g l o c k e d 6 - 0 c h r o m i c o r i n t e r r u p t e d 6 -

0 n y l o n s u t u r e .

Composite Graft. A n o t h e r s a t i s f a c t o r y m e t h o d o f

r e p a i r i n g s m a l l d e f e c t s o f t h e p i n n a ( n o g r e a t e r t h a n

3 c m ) i s t o u s e a c o m p o s i t e g ra f t f r o m t h e o p p o s i t e

e a r . A t h r o u g h - a n d - t h r o u g h gra f t up t o 1.5 cm in

s i z e c a n b e h a r v e s t e d f r o m t h e d o n o r e a r . T h e s i z e

o f t h e g ra f t i s u s u a l l y h a l f t h e s i z e o f t h e d e f e c t —

t h a t i s , f o r a 2 - c m d e f e c t a 1-cm c o m p o s i t e g ra f t i s

h a r v e s t e d . T h e d o n o r s i t e i s c l o s e d p r i m a r i l y a s

d e s c r i b e d a b o v e . T h e c o m p o s i t e g ra f t i s t h e n s u t u r e d

i n p l a c e w i t h a m i n i m a l n u m b e r o f s u t u r e s , s e c u r i n g

t h e c a r t i l a g e w i t h 5 - 0 V i c r y l a n d c l o s i n g t h e s k i n w i t h

6 - 0 c h r o m i c o r n y l o n s u t u r e . T o o m a n y s u t u r e s c a n

c o m p r o m i s e t h e v i a b i l i t y o f t h e g r a f t . C o m p o s i t e

g ra f t s o f t e n u n d e r g o e p i d e r m o l y s i s w i t h d i s c o l o r a ­

t i o n a n d b l i s t e r f o r m a t i o n , b u t u s u a l l y r e - e p i t h e l i a l i z e

i f i n f e c t i o n i s a v o i d e d .

Pedicled Skin Flap. F o r l a r g e r d e f e c t s , a s k i n f l ap

b a s e d e i t h e r a n t e r i o r l y o r p o s t e r i o r l y o n t h e p o s t a u -

r i c u l a r s k i n i s e l e v a t e d a n d s u t u r e d i n t o t h e d e f e c t

( F i g . 2 0 - 5 C , D). I f t h e d e f e c t h a s b e e n c r e a t e d b y

r e s e c t i o n o f a n e o p l a s m o r a t r a u m a t i c t i s s u e l o s s , a n

a n t e r i o r l y b a s e d f lap i s n o t f e a s i b l e . T h e b l o o d s u p p l y

i s b e t t e r w h e n t h e f lap i s b a s e d p o s t e r i o r l y , b u t

a n t e r i o r l y b a s e d f l a p s u s u a l l y d o n o t r e q u i r e a s e c ­

o n d a r y t a k e d o w n p r o c e d u r e . T h e l e n g t h - t o - w i d t h

r a t i o i s u s u a l l y l o w (1:1 t o 2 : 1 ) b e c a u s e o f t h e c l o s e

p r o x i m i t y o f t h e d o n o r s i t e . A p i e c e o f c o n t r a l a t e r a l

c o n c h a l b o w l c a r t i l a g e o r c o s t a l c a r t i l a g e c a n b e

p l a c e d u n d e r t h e f l a p p r i m a r i l y , o r s e c o n d a r i l y w h e n

t h e f lap i s t a k e n d o w n ( F i g . 2 0 - 5 E ) . F o r s m a l l d e f e c t s

t h e u s e o f c a r t i l a g e i s n o t n e c e s s a r y . T h e p o s t a u r i c -

u la r s u l c u s o f t e n c a n b e p r e s e r v e d b y l e a v i n g a s t r i p

o f p o s t a u r i c u l a r s k i n i n t a c t w h e n d e v e l o p i n g t h e f l ap .

T h e f r e e m a r g i n o f s k i n o n t h e m e d i a ) s u r f a c e o f t h e

p i n n a i s s u t u r e d t o t h e f r e e m a r g i n o f t h e p o s t a u r i c ­

u l a r s k i n . T h e l e a d i n g e d g e o f t h e e l e v a t e d f lap i s

s u t u r e d t o t h e f ree m a r g i n o f t h e l a t e r a l s k i n o f t h e

p i n n a . A f t e r t h r e e o r f o u r w e e k s t h e p e d i c l e d f lap

c a n b e s e p a r a t e d f r o m t h e p o s t a u r i c u l a r s k i n a n d

r o l l e d a r o u n d t o m a k e a n e w h e l i c a l r im ( F i g . 2 0 - 5 F ,

C ) . I f t h e h e l i c a l fo ld i s n o t w e l l d e f i n e d , s m a l l c o t t o n

b o l s t e r s c a n b e p l a c e d o n t h e l a t e ra l s u r f a c e o f t h e

p i n n a a n d s u t u r e d i n p l a c e w i t h 4 - 0 n y l o n t o h e l p

r e c r e a t e t h i s p o r t i o n . S u b c u t a n e o u s a n d c a r t i l a g i n o u s

s u t u r e s a r e 5 - 0 V i c r v l , w i t h 6 - 0 c h r o m i c o r n y l o n

u s e d for t h e c u t a n e o u s l a y e r . T h e d o n o r s i t e u s u a l l y

c a n b e c l o s e d p r i m a r i l y w i t h e x t e n s i v e u n d e r m i n i n g ,

b u t a s k i n g ra f t m a y b e n e c e s s a r y .

D e f e c t s o f t h e c o n c h a l b o w l c a n b e c l o s e d p r i m a r i l y

i f t h e y a r e s m a l l . F o r a l a r g e r d e f e c t , a f u l l - t h i c k n e s s

p o s t a u r i c u l a r s k i n g ra f t w o r k s w e l l . L a r g e d e f e c t s

a l s o m a y b e r e p a i r e d w i t h a p o s t a u r i c u l a r p e d i c l e d

s k i n f l ap , w h i c h i s e l e v a t e d a n d la id t h r o u g h a slit

m a d e t h r o u g h t h e c o n c h a l c a r t i l a g e ( F i g . 2 0 - 6 / 1 ) . T h e

f l ap i s s u t u r e d a n t e r i o r l y , s u p e r i o r l y , a n d i n t e r i o r l y ,

l e a v i n g t h e p o s t e r i o r t h r o u g h - a n d - t h r o u g h s l i t ( F i g .

2 0 - 6 8 ) . A f t e r t h r e e o r f o u r w e e k s t h e f l ap i s r e l e a s e d

a l o n g t h e p o s t e r i o r sl i t a n d t h e d e f e c t i s c l o s e d

p r i m a r i l y ( F i g . 2 0 - 6 C ) .

L o s s o f t h e e a r l o b e c a n b e r e p a i r e d b y d e s i g n i n g

a b i l o b e d f l ap b a s e d a n t e r i o r l y , w h i c h i s l i f t ed a n d

f o l d e d u p o n i t s e l f ( F i g . 2 0 - 7 / 1 , B ) . T h e d o n o r s i t e i s

350 P l a s t i c S u r g e r y o f t h e P i n n a

FIGURE 2(1-5

FIGURE 20-6

P l a s t i c S u r g e r y o f t h e P i n n a 353

c l o s e d p r i m a r i l y o r w i t h a s k i n g r a f t . A l t e r n a t i v e l y ,

a n i n t e r i o r l y b a s e d f l a p i s e l e v a t e d a n d s u t u r e d t o

t h e i n f e r i o r e d g e o f t h e r e m a i n i n g p i n n a . A f t e r t h r e e

t o f o u r w e e k s t h e f lap i s s e p a r a t e d i n t e r i o r l y a n d

f o l d e d u p o n i t s e l f ( F i g . 2 0 - 7 C - E ) .

Postoperative Care

B a c i t r a c i n o i n t m e n t i s a p p l i e d t o t h e i n c i s i o n s . A

l i g h t m a s t o i d d r e s s i n g i s a p p l i e d t o p r e v e n t t h e

p a t i e n t f r o m d i s t u r b i n g t h e r e p a i r . T o o t i g h t a d r e s s ­

i n g m i g h t c o m p r o m i s e t h e b l o o d s u p p l y . T h e d r e s s ­

i n g c a n b e r e m o v e d i n a f e w d a y s , a n d t h e b a c i t r a c i n

i s c o n t i n u e d for a n o t h e r d a y o r t w o . I f a t a k e d o w n

i s n e c e s s a r y , i t i s p e r f o r m e d a f t e r t h r e e t o t o u r w e e k s .

A f t e r t h e s e c o n d s t a g e o f a p e d i c l e d f lap t h e r e i s

u s u a l l y e d e m a o f t h e f lap s i d e o f t h e f l a p / n o r m a l s k i n

i n t e r f a c e ; t h i s m a k e s t h e r e p a i r m o r e n o t i c e a b l e a n d

m a y t a k e s e v e r a l m o n t h s t o r e s o l v e . If, a f t e r s ix t o

n i n e m o n t h s , a d e p r e s s e d s c a r h a s f o r m e d ( t h i s c a n

b e e s p e c i a l l y n o t i c e a b l e o n t h e h e l i c a l r i m ) , a s m a l l

Z - p I a s t y c a n b e p e r f o r m e d u n d e r l o c a l a n e s t h e s i a .

Otoplasty

E x c l u d i n g m i c r o t i a , t h e t w o g e n e r a l t y p e s o f c o n ­

g e n i t a l m a l f o r m a t i o n s o f t h e p i n n a a r e l o p e a r s a n d

p r o m i n e n t e a r s . A l o p e a r o c c u r s w h e n t h e s u p e r i o r

p o r t i o n o f t h e h e l i c a l r im i s f o l d e d d o w n l i ke a h o o d

o v e r t h e r e s t o f t h e p i n n a . T h e c a r t i l a g e i s f o l d e d o n

i t s e l f a t a n a c u t e a n g l e . A p r o m i n e n t e a r c a n b e d u e

t o e i t h e r t h e l a c k o f t h e a n t h e l i c a l fo ld o r a n o v e r p r o -

j e c l i n g c o n c h a l b o w l . T h e n o r m a l a n g l e o f t h e e a r s

t o t h e s k u l l i s 3 0 d e g r e e s , a n d a n o r m a l p r o j e c t i o n

f rom t h e p o s t a u r i c u l a r a r e a t o t h e m i d d l e o n e - t h i r d

o f t h e h e l i x i s 1 7 t o 2 0 m m . S u r g i c a l c o r r e c t i o n i s

p e r f o r m e d w h e n a p a t i e n t o r p a r e n t , i f t h e p a t i e n t i s

a c h i l d , r e q u e s t s i t a n d t h e r e a r e n o m e d i c a l c o n t r a i n ­

d i c a t i o n s . C h i l d r e n a r e u s u a l l y o p e r a t e d o n b e f o r e

s t a r t i n g s c h o o l t o a v o i d a n y r i d i c u l e t h e i r d e f o r m i t y

m i g h t c a u s e

Aim

T o c o r r e c t t h e d e f o r m i t y p r e s e n t i n e i t h e r a l o p o r

a p r o m i n e n t e a r .

Highlights

1. A d u m b b e l l - s h a p e d p o s t a u r i c u l a r i n c i s i o n i s

u s e d .

2 . E x c e s s c a u d a h e l i x i s r e s e c t e d .

3 . E x c e s s c o n c h a l b o w l c a r t i l a g e i s r e s e c t e d a t t h e

e x t e r n a l a u d i t o r y m e a t u s .

Pitfalls

1 . C o l l a p s e o f t h e e x t e r n a l a u d i t o r y c a n a l m a y

o c c u r i f a n i n s u f f i c i e n t a m o u n t o f c o n c h a l b o w l c a r ­

t i l a g e i s r e m o v e d w h e n t h e c o n c h a l - m a s t o i d s u t u r e s

a r e p l a c e d .

2 . F a i l i n g ' t o r e s e c t e x c e s s c a u d a h e l i x .

3 . A s h a r p - e d g e d a n t h e l i c a l f o ld m a y r e s u l t f r o m

t o o d e e p c r o s s h a t c h i n g f r o m t h e m e d i a l s u r f a c e o f

t h e e a r .

4 . I m p r e c i s e m e a s u r i n g m a y r e s u l t i n a s y m m e t r y

b e t w e e n t h e t w o e a r s .

Instruments

A b a s i c p l a s t i c s p a c k .

M e t h y l e n e b l u e d y e .

A 2 2 - g a u g e n e e d l e .

Procedure

G e n e r a l a n e s t h e s i a c o m m o n l y i s u s e d s i n c e t h e

o p e r a t i o n i s m o s t o f t e n p e r f o r m e d o n c h i l d r e n ; h o w ­

e v e r , l o c a l a n e s t h e s i a c a n b e u s e d i n a d u l t s . G e n e r ­

a l ly , a p a t i e n t w i t h l o p o r p r o m i n e n t e a r s p r e s e n t s

a s a y o u n g c h i l d for c o r r e c t i v e s u r g e r y . O c c a s i o n a l l y ,

a n e w b o r n i n f a n t i s s e e n w i t h i n t h e f irst d a y o r t w o

o f l i fe w i t h a p r o m i n e n t o r l o p e a r , a n d i t i s p o s s i b l e

t o c o r r e c t t h e d e f e c t n o n s u r g i c a l l y . I m m e d i a t e l y a f t e r

b i r t h m a t e r n a l e s t r o g e n s a r e st i l l p r e s e n t i n t h e i n f a n t ,

w h i c h m a k e s t h e c a r t i l a g e sof t a n d m a l l e a b l e ; s t e n t -

i n g o f t h e s e d e f o r m i t i e s i n t h e n e o n a t a l p e r i o d i s

s u c c e s s f u l u n t i l t h e d r o p i n m a t e r n a l e s t r o g e n s c a u s e s

t h e c a r t i l a g e t o b e c o m e f i rm a n d r e s i s t a n t t o s t r u c t u r a l

c h a n g e . U s i n g S t e r i - S t r i p s a n d c o t t o n , t h e i n f a n t ' s

e a r i s f o r m e d a n d t a p e d i n t o p r o p e r p o s i t i o n . T h e

e a r m u s t b e t a p e d i n t h i s m a n n e r f o r . t w o t o t h r e e

m o n t h s ( F i g . 2 0 - 8 / 1 , B).

Text continued on page 358

354 P l a s t i c S u r g e r y o f t h e P i n n a

PICURE 20-8,

P l a s t i c S u r g e r y o f t h e P i n n a 355

FIGURE 20-9.

FIGURE 20-1(1

P l a s t i c S u r g e r y o f t h e P i n n a 357

FIGURE 20-11

. I IU..LK J U J g C I } - III I M f J 'J l l l lc l

T o c o r r e c t a l o p e a r s u r g i c a l l y , a n i n c i s i o n i s m a d e

a l o n g t h e m e d i a l e d g e o f t h e h e l i c a l r i m ( F i g . 2 0 - 8 C ) .

T h e sof t t i s s u e s o n b o t h s i d e s o f t h e " h o o d e d " p i n n a

a re e l e v a t e d , t h u s e x p o s i n g t h e d e f o r m e d c a r t i l a g e .

V e r t i c a l i n c i s i o n s a r e m a d e d o w n t h r o u g h t h e h e l i x

all t h e w a y t o t h e c o n c h a l b o w l , a l l o w i n g t h e f o l d e d

c a r t i l a g e t o u n f o l d a n d f l a re o u t . A s t r u t o f c o n c h a l

b o w l c a r t i l a g e i s s u t u r e d t o t h e m e d i a l s u r f a c e o f t h e

n e w h e l i c a l r i m t o g i v e m o r e s u p p o r t ( F i g . 2 0 - 8 D , ) . I f

e n o u g h s k i n i s p r e s e n t , p r i m a r y c l o s u r e i s o b t a i n e d

w i t h 5 - 0 V i c r y l a n d e i t h e r 6 - 0 c h r o m i c o r n y l o n

s u t u r e s ; o t h e r w i s e a p o s t a u r i c u l a r f l ap l i k e t h a t u s e d

for r e p a i r o f p i n n a d e f e c t s i s e l e v a t e d a n d s u t u r e d

i n t o p l a c e . S m a l l b o l s t e r s o f c o t t o n s e c u r e d w i t h 4 - 0

n y l o n s u t u r e h e l p g i v e d e f i n i t i o n t o t h e h e l i c a l r im

( F i g . 2 0 - 8 E ) .

T h e c o r r e c t i o n o f p r o m i n e n t e a r s d e p e n d s o n

w h e t h e r t h e d e f o r m i t y i s o v e r p r o j e c t i o n o f t h e c o n ­

c h a , l a c k o f a n a n t h e l i c a l f o l d , o r a c o m b i n a t i o n o f

t h e t w o . M o s t p r o m i n e n t e a r s h a v e a n e l e m e n t o f

b o t h d e f o r m i t i e s .

A w o o d e n t o n g u e b l a d e i s u s e d t o m e a s u r e t h e

r i g h t a n d lef t e a r s a t t h e s t a r t o f t h e p r o c e d u r e s o

t h a t s y m m e t r y c a n b e o b t a i n e d ( F i g . 2 0 - 9 A ) . A f t e r

t h e f irst e a r i s f i n i s h e d , i t s p r o j e c t i o n i s m a r k e d o n

t h e t o n g u e b l a d e a n d u s e d a s a g u i d e for t h e s e c o n d

e a r .

A d u m b b e l l - s h a p e d i n c i s i o n i s m a d e o n t h e m e d i a l

s u r f a c e o f t h e p i n n a a n d t h e e l l i p s e o f s k i n a n d sof t

t i s s u e s i s r e m o v e d ( F i g . 2 0 - 9 8 ) . I f t h e r e i s o n l y s l i g h t

o v e r p r o j e c t i o n o f t h e c o n c h a , c o n c h a l - m a s t o i d s u ­

t u r e s o f 4 - 0 w h i t e E t h i b o n d a r e p l a c e d i n a m a t t r e s s

p a t t e r n f r o m t h e m a s t o i d p e r i o s t e u m t o t h e c o n c h a l

b o w l p e r i c h o n d r i u m ( F i g . 2 0 - 9 C ) . E x t r a c o r r e c t i o n

c a n b e o b t a i n e d b y r e m o v i n g s m a l l d i s k s o f c o n c h a l

b o w l c a r t i l a g e a t t h e c o n c h a l - m a s t o i d j u n c t i o n ( F i g .

2 0 - 9 D ) . A s h a r p No. 1 5 b l a d e i s u s e d t o s h a v e t h e

d i s k s f r o m t h e m e d i a l s u r f a c e o f t h e c o n c h a l b o w l ,

c a r e i s t a k e n t o l e a v e a l a v e r o f c a r t i l a g e a n d pe r i ­

c h o n d r i u m i n t a c t o n t h e l a t e r a l s u r f a c e C a u t i o n

s h o u l d b e e x e r c i s e d w h e n t h e c o n c h a l b o w l i s

b r o u g h t b a c k i n t o p r o p e r p o s i t i o n b e c a u s e t h e a n t e ­

r io r c o n c h a l b o w l c a r t i l a g e c a n p r o j e c t i n t o t h e e x t e r ­

n a l a u d i t o r y c a n a l a n d n a r r o w i t . I f t h e c a n a l i s m a d e

t o o n a r r o w , t h i s e x c e s s c a r t i l a g e s h o u l d b e e x c i s e d .

T h e a n t h e l i c a l f o l d i s c o r r e c t e d t h r o u g h t h e s a m e

i n c i s i o n . T h e p r o p o s e d a n t h e l i c a l f o ld i s o u t l i n e d o n

t h e l a t e r a l s u r f a c e o f t h e p i n n a w i t h a m a r k i n g p e n

( F i g . 2 0 - 1 0 / 4 ) . T h e s u r g e o n o f t e n c a n g e t a c l e a r i d a

o f w h e r e t h e a n t h e l i c a l fo ld s h o u l d e x i s t b y g e r l y

p r e s s i n g t h e h e l i c a l r i m t o w a r d t h e h e a d ; t h e u n -

p r o n o u n c e d a n t h e l i c a l f o l d w i l l a p p e a r o v e r t h e for ­

m e r l y flat s u r f a c e o f t h e s c a p h o i d r e g i o n . A 2 2 - g a t g e

n e e d l e i s p a s s e d t h r o u g h t h e l a t e r a l s k i n a n d c a r t i l c j ; e

a n d i n t o t h e p o s t a u r i c u l a r i n c i s i o n . M e t h y l e n e b l i e

d y e i s t h e n a p p l i e d t o t h e n e e d l e t ip a n d t h e nee< ! a

i s w i t h d r a w n ( F i g . 2 0 - 1 0 6 ) . T h i s m a r k s t h e m e d a l

s u r f a c e o f t h e c a r t i l a g e a n d s e r v e s a s a g u i d e t t r

s u t u r e p l a c e m e n t . T h e c a r t i l a g e a l o n g t h e m e d l l

s u r f a c e o f t h e p r o p o s e d a n t h e l i c a l fo ld i s s c o r e d w i h

a N o . 1 5 b l a d e t h r o u g h t h e c a r t i l a g e , b u t n o t t h r o u ^ h

t h e p e r i c h o n d r i u m o n t h e l a t e r a l s u r f a c e ( F i g . 2 1 -

1 0 C ) . I f t h e i n c i s i o n s a r e t h r o u g h - a n d - t h r o u g h , e . i

u n a t t r a c t i v e a n t h e l i c a l fo ld r e s u l t s . N e x t , t e m p o r a r /

4 - 0 s i l k h o r i z o n t a l m a t t r e s s s u t u r e s a r e p l a c e i

t h r o u g h t h e l a t e r a l s u r f a c e o f t h e p i n n a , t h r o u g h t h ' .

c a r t i l a g e , a n d b a c k o u t t h e l a t e r a l s u r f a c e , u s i n g t h •

m a r k s m a d e a s a g u i d e T e m p o r a r y s t a y s u t u r e s a l l o v

t h e s u r g e o n t o " a d j u s t " t h e a n t h e l i c a l f o ld t o o b t a i r

s y m m e t r y w i t h t h e o p p o s i t e e a r ( F i g . 2 0 - 1 0 D ) . W h i t '

4 - 0 E t h i b o n d h o r i z o n t a l m a t t r e s s s u t u r e s a r e t h e

p l a c e d o n t h e m e d i a l s u r f a c e o f t h e c a r t i l a g e t h r o u g h

t h e p o s t a u r i c u l a r i n c i s i o n ( F i g . 2 0 - 1 0 E ) . C a r e m u s t

b e t a k e n n o t t o e x i t t h r o u g h t h e l a t e r a l s u r f a c e s k i n

W h e n t h r e e t o f o u r s u t u r e s a r e i n p l a c e t h e t e m p o r a r y

s i l k s u t u r e s a r e r e m o v e d . A n a n t h e l i x h a s n o w b e e n

f o r m e d ( F i g . 2 0 - 1 0 F ) .

W i t h t h e e a r n o w i n p r o p e r p o s i t i o n , t h e a p p e a r ­

a n c e o f t h e c a u d a h e l i x m u s t b e a s s e s s e d ( F i g . 2 0 -

1 1 / 1 , B). E x c e s s p r o j e c t i o n s h o u l d b e r e m o v e d ( b v

c u t t i n g t h e C a u d a h e l i x ) o r m o r s c l i / e d ( b v s c o r i n g ) s o

t h a t i t l i e s f l a t t e r ( F i g . 2 0 - 1 1 C , I ) ) . The s k i n o n t h e

l a t e r a l s u r f a c e o f t h e p i n n a i n t h e r e g i o n o f t h e c a u d a

h e l i x s h o u l d a l s o b e u n d e r m i n e d , s o t h a t a f t e r r e s e c ­

t ion o f t h e C a u d a h e l i x t h e s k i n r e d r a p e s p r o p e r l y .

1 h e p o s t a u r i c u l a r i n c i s i o n i s c l o s e d w i t h 4 - 0 V i c r y l

a n d 6 - 0 c h r o m i c o r n v l o n s u t u r e s , a n d a b i l a t e r a l

m a s t o i d d r e s s i n g i s a p p l i e d . T h e d r e s s i n g c a n b e lefl

o n ( o r o n e w e e k l o p r e v e n t t r a u m a t o t h e e a r s . I f

n y l o n s u t u r e s h a v e b e e n u s e d , t h e y c a n b e r e m o v e d

w h e n t h e d r e s s i n g i s r e m o v e d . T h e p a t i e n t m u s t b e

c a u t i o n e d a g a i n s t e n g a g i n g i n c o n t a c t s p o r t s u n t i l s ix

w e e k s a f t e r t h e s u r g e r y .

SECTION V

Selected References

A n s o n F3J a n d D o n a l d s o n J A : Surgical Anatomy of the Temporal Bone, 3 r d e d .

P h i l a d e l p h i a , W B S a u n d e r s C o , 1 9 8 1 .

B a i l e y B J : C o c h l e a r p r o s t h e s i s i m p l a n t a t i o n : R e v i e w o f t h e i s s u e s ( e d i t o r i a l ) .

J A M A 2 5 1 : 3 2 8 2 , 1 9 8 4 .

B r a c k m a n D E : Neurological Surgery of Ear and Skull Base. N e w Y o r k , R a v e n P r e s s ,

1 9 8 2 .

B r a n t - Z a w a d z k i M a n d N o r m a n D: Magnetic Resonance Imaging of the Central

Nervous System. N e w Y o r k , R a v e n P r e s s , 1 9 8 5 .

C h a k e r e s E W a n d L a M a s t e r s D L : P a r a g a n g l i o m a s o f t h e t e m p o r a l b o n e : H i g h

r e s o l u t i o n C T s t u d i e s . R a d i o l o g y 2 5 0 : 7 4 9 - 7 5 3 , 1 9 8 4 .

D a n i e l s D L , M i l l e n S J , M e y e r G A , e t a l : M R d e t e c t i o n o f t u m o r i n t h e i n t e r n a l

a u d i t o r y c a n a l . A J N R 8 : 2 4 9 - 2 5 2 , 1 9 8 7 .

D o y l e P J : I n d i c a t i o n s for a n d t e c h n i q u e o f e n d a u r a l a n d p o s t a u r i c u l a r i n c i s i o n s .

O t o l a r y n g o l 6 : 2 6 2 - 2 6 6 , 1 9 7 7 .

F a r r i o r J B : I n c i s i o n s i n t y m p a n o p l a s t y : A n a t o m i c c o n s i d e r a t i o n s a n d i n d i c a t i o n s .

L a r y n g o s c o p e 9 3 : 7 5 - 8 6 , 1 9 8 3 .

F i s c h U: Tympanoplasty and Stapedectomy. N e w Y o r k , T h i e m e - S t r a t t o n , 1 9 8 0 .

F r i e d m a n n 1: Pathology of the Ear. O x f o r d , B l a c k w e l l S c i e n t i f i c P u b l i c a t i o n s , 1 9 7 4 ,

G a c e k R R : T r a n s e c t i o n o f t h e p o s t e r i o r a m p u l l a r y n e r v e for t h e r e l i e f o f b e n i g n

p a r o x y s m a l p o s i t i o n a l v e r t i g o . A n n O t o l R h i n o l L a r y n g o l 8 3 : 5 9 6 - 6 0 5 , 1 9 7 4 .

G a l l a g h e r J C : Histology of the Human Temporal Bone. A m e r i c a n R e g i s t r y of

P a t h o l o g y . W a s h i n g t o n D C , A r m e d F o r c e s I n s t i t u t e o f P a t h o l o g y , 1 9 6 7 .

G o o d h i l l V : S u d d e n d e a f n e s s a n d r o u n d w i n d o w r u p t u r e . L a r y n g o s c o p e

8 1 : 1 4 6 2 - 1 4 7 4 , 1 9 7 1 .

G r i f f i n C , D e L a P a z R , a n d E n z m a n n D : M R a n d C T c o r r e l a t i o n o f c h o l e s t e r o l

c y s t s o f p e t r o u s b o n e . A J N R 8 : 8 2 5 - 8 2 9 , 1 9 8 7 .

H o u s e W F : S u r g i c a l c o n s i d e r a t i o n s i n c o c h l e a r i m p l a n t a t i o n . A n n O t o l R h i n o l

L a r y n g o l 9 1 ( S u p p l ) : 1 5 - 2 0 , 1 9 8 2 .

H o u s e W F a n d L u e t j e C M : Acoustic Tumors, V o l s I a n d I I . B a l t i m o r e , U n i v e r s i t y

P a r k P r e s s , 1 9 7 9 .

| a n s e n C : P o s t e r i o r t y m p a n o t o m y : E x p e r i e n c e a n d s u r g i c a l d e t a i l s . O t o l a r y n g o l

C l i n N o r t h A m 5 : 7 9 - 9 6 , 1 9 7 2 .

L a t a c k J T , K a r t u s h J M , K e m i n k J L , e t a l : E p i d e r m o i d o m a s o f t h e c e r e b e l l o ­

p o n t i n e a n g l e a n d t e m p o r a l b o n e : C T a n d M R a s p e c t s . R a d i o l o g y 1 5 7 : 3 6 1 -

3 6 6 , 1 9 8 5 .

L i m D J : H u m a n t y m p a n i c m e m b r a n e . A c t a O t o l a r y n g o l 7 0 : 1 7 6 - 1 8 6 , 1 9 7 0 .

L i m D J : F u n c t i o n a l m o r p h o l o g y o f t h e l i n i n g m e m b r a n e o f t h e m i d d l e e a r a n d

e u s t a c h i a n t u b e . A n o v e r v i e w . A n n O t o l R h i n o l L a r y n g o l 8 3 ( S u p p l ) : 5 - 2 6 ,

1 9 7 4 .

M a r q u e t J F E ( e d ) : Surgery and Pathology of the Middle Ear. B o s t o n , M a r t i n u s

N i j h o f f , 1 9 8 5 .

N a g e r G T a n d N a g e r M : A r t e r i e s o f t h e h u m a n m i d d l e e a r , w i t h p a r t i c u l a r

r e g a r d t o t h e b l o o d s u p p l i e s o f t h e a u d i t o r y o s s i c l e s . A n n O t o l R h i n o l

L a r y n g o l 6 2 : 9 2 3 - 9 4 9 , 1 9 5 3 .

N a u m a n n HH: Head and Neck Surgery. Vol 3: Ear. P h i l a d e l p h i a , WB S a u n d e r s

C o , 1 9 8 2 .

N a u n t o n R F : T y m p a n o s t o m y t u b e s : T h e c o n s e r v a t i v e a p p r o a c h . A n n O t o l

R h i n o l L a r y n g o l 9 0 : 5 2 9 - 5 3 2 , 1 9 8 1 .

P a p a r e l l a M M a n d S h u m r i c k D A : Otolaryngology ( V o l s . 1 a n d 3 ) . P h i l a d e l p h i a ,

W B S a u n d e r s C o , 1 9 8 8 .

P o r t m a n n M: The Ear and Temporal Bone. N e w Y o r k , M a s s o n , 1 9 7 9 .

362 S e l e c t e d R e f e r e n c e s

P r o c e e d i n g s o f t h e s e c o n d i n t e r n a t i o n a l s y m p o s i u m a n d w o r k s h o p s o n s u r g e r y

o l ( h e i n n e r e a r ( S n n w m a s s , A s p e n , C o l o r a d o ) : T a r t 2 . A m J O t o l 8 : 2 7 1 -

3 6 8 , 1 9 8 7 .

I ' r o c t o r B : T h e d e v e l o p m e n t o f t h e m i d d l e e a r s p a c e s a n d t h e i r s u r g i c a l

s i g n i f i c a n c e . J L a r y n g o l O t o l 7 8 : 6 3 1 - 6 4 8 , 1 9 6 4 .

P r o c t o r B a n d N a g e r C T : T h e fac ia l c a n a l : N o r m a l a n a t o m y , v a r i a t i o n s a n d

a n o m a l i e s . T r a n s A m O t o l S o c 7 0 : 4 9 , 1 9 8 2 .

S c h u k n e c h t H P : Stapedectomy. B o s t o n , L i t t l e , B r o w n & C o , 1 9 7 1 .

S c h t t k n e c h t H F : Pathology o f the Ear. C a m b r i d g e , H a r v a r d U n i v e r s i t y P r e s s ,

1 9 7 4 .

S c h u k n e c h t 14F a n d G u l y a J A : Anatomy of the Temporal Bone with Surgical

Implications. P h i l a d e l p h i a , L e a a n d F e b i g e r , 1 9 8 6 .

S h a m b a u g h C f i J r a n d G l a s s c o c k ME III: Surgery o f the Ear, 3 r d e d . P h i l a d e l p h i a ,

W B S a u n d e r s C o , 1 9 8 0 .

S h e a ' D , C h o l e R , a n d P a p a r e l l a M M : T h e e n d o l y m p h a t i c s a c : A n a t o m i c a l

c o n s i d e r a t i o n s . L a r y n g o s c o p e 8 9 : 8 8 - 9 4 , 1 9 7 9 .

S u r g i c a l i m p l a n t a t i o n t e c h n i q u e for X o m e d A u d i a n t B o n e C o n d u c t o r ( b a s e d o n

t h e t e c h n i q u e o f J . H o u g h ) ( p u b . n o . 5 0 - 1 5 0 0 ) . J a c k s o n v i l l e , X o m e d I n c , 1 9 8 6 .

S w a r t z J D : Imaging of the Temporal Bone: A Text-Atlas. N e w Y o r k , T h i e m e , 1 9 8 6 .

W o l f f D, B e l l u c c i R J , a n d E g g s t o n A A : Surgical and Microscopic Anatomy of the

Temporal Bone. N e w Y o r k , H a f n e r P u b l i s h i n g C o , 1 9 7 1 .

Index

Page numbers in italic* indicate illustrations

A

Abscess(es), intracranial, complicating suppurative otitis media, 194, 196

periauricular, complicating suppurative otitis media, 797, 198

Acoustic meatus, external, 5, 6 Acoustic nerve, 21 Acoustic neuromas, translabyrinthine approach

for, 331-338. Sec a/so Translabyrinthine approach, for acoustic neuromas

Acoustic schwannoma, intracanalicular CT and MR imaging of, 31

Adhesions/tissue, for ossicular chain grafting, 223

Adhesive otitis, tympanoplasty for, 175, 177, 178-180

Aeration lubes, transmeatal permanent, for otitis media, 171-173

Allograft, for total perforation, 233, 234 Ampullae, 20 Amputation of pinna, total, plastic surgery for,

345-347, 348 Anatomy, pertinent, 3-22 Anesthesia, for otologic procedures, 102 Annular ligament, 12 Antibiotics, prophylactic, for otologic

procedures, 102 Artery(ies), of external ear, 7, 8

of inner ear, 21 of middle ear, 14, 75

Atelectatic tympanic membrane, histopathologv of, 203

tympanoplasty for, 175, 177, 178-179 Atherosclerosis screening, vascular ultrasounc

for, 28, 35 Atresia, congenital. Sec Congenital atresia. Auditory canal, internal, middle fossa

approach to, 93, 95-96, 97 translabyrinthine approach to, 87, 89, 90, 91

Auditory nerve, 21 Auditory tube, 12, 14 Auricle, anatomy of, 3 -6

plastic surgery of, 339-358. See also Plastic surgery of pinna.

Auricular artery, posterior, 14 stylomastoid branch of, 8

Auricular branch, of vagus nerve, 8 Auricular nerve, great, 8 Auricular rami, 8 Auriculotemporal branch, of trigeminal nerve,

8

B

Basilar membrane, of osseous labyrinth, 19 Biopsv, of externa] auditory canal tumors, 153,

154 Bleeding, complicating total stapedectomy with

prosthesis, 257

Bleeding (Continued) jugular bulb, complicating translabyrinthine

approach for acoustic neuromas, 337 sinus, complicating translabyrinthine

approach for acoustic neuromas, 337 Block method, for temporal bone removal, 39,

40 Blood vessels, of external ear, 7, 8 Bone, cortical, for ossicular chain grafting, 222

skull transcochlear approach to, 90, 92, 93, 94

temporal. See Temporal bone. Bone conduction hearing devices, surgical

approach for, 281-285. See also Hearing devices, bone conduction, surgical approach for.

Bone plug method, for temporal bone removal, 40-41, 43

Bundle of Oort, 22

C

Canalplasty, 59, 62, 63, 149-151, 152 in exploratory tympanotomy, 127, 129, 130

Caroticotympanic artery, 14 Carotid artery, cervical, atherosclerosis of,

vascular ultrasound screening for, 28, 35 external, posterior auricular branch of, 8

Carotid wall, of middle ear, 10 Cartilage, for ossicular chain grafting, 222 Cartilage tympanoplasty, for atrophic tympanic

membrane, 173-175, 176 Ceramics, for ossicular chain grafting, 222 Cerebellopontine angle, retrolabyrinthine

approach to, 82, 85, 87, 88 with vestibular nerve sectioning, for

incapacitating peripheral vertigo, 307, 309, 370-317

Cerebrospinal fluid leak, complicating total stapedectomy with prosthesis, 261

Chemodectoma, of jugular foramen, MR imaging of, 32

Cholesteatoma, CT imaging of, 30 Cholesterol granuloma, of medial petrous

apex, MR imaging of, 33 Chorda tympanic branch, of facial nerve, 16 Cleft ear lobe, plastic surgery for, 339-341, 342 Closed-cavity tympanomastoidectomy, for

otitis media, 181-183, 184 meatoplasty in, 140, 747

Coalescent mastoiditis, complicating suppurative otitis media, 192

Cochlea, 19 Cochlear aqueduct, 19 Cochlear artery, 21 Cochlear division, of vestibulocochlear nerve,

22 Cochlear duct, 20 Cochlear fossa, of middle ear, 10 Cochlear implant(s), 75, 82, 83-84

components of, 286 facial recess approach to, 54, 55-58, 59 surgical approaches for, 286-296

3 6 3

3 6 4 I n d e x

Cochlear implant(s) (Continued) surgical approaches for, mastuidotomy/

tympanotomy as 2S7

Gochlcariform prna^s, in middle e« 1U

22o"'2fi r ° f ' f ° r t y m p a n i c m ^ b r a n c .

Computed tomography (CT) imaging, of temporal bone, 28, 29-31 , 34

Congenital atresia, 159-163 histopathology of, 163 surgical technique for, 159-163

Congenital malformations, of pinna, plastic surgery for, 353-358

Consent, patient, preoperative, 101-102 Cortical bone, for ossicular chain grafting, 222 Cortical mastoidectomy, for otitis media, 181 Cristae, 20 Cupula, 20

Descending artery, H Drainage, petrous, 71, 72 Drills, in operating room, 107 Ductus reuniens, 20 Dura mater exposure, complicating simple

mastoidectomy, 135, 137

Earlobe, cleft, plastic surgery for, 339-341, 342 Elliptical recess, of osseous labyrinth, 18 Endaural approach, to external ear canal and

middle car, 130-132 Endolymphatic duct, 20 Endolymphatic sac, 20

procedures on, for incapacitating peripheral vertigo, 297-298, 299-301

surgery on, 47, 49, 50-51 Endosteum, of osseous labyrinth, 19 Epitympanic cells, 17 Epitympanic recess, of tympanic cavity, 9 Epitympanum, 24 Equipment, and procedures in operating room,

102-111 for temporal bone removal, 42, 43

Eustachian tube, 12, 14 Exostosis, canalplasty for, 149, 750, 151 "Exteriorized" mastoid cavity, for otitis media

191 External acoustic meatus, 5, 6 External ear, anatomy of, 3-8

auricle of, 3 - 6 bony features and relationships of, 3 canal of, approach to, endaural, 130-132

mastoidotomv as, 137-138 meatoplasty as, 138-140, 141 postauricular, 132-133, 134 posterior tympanotomy as, 137 simple mastoidectomy as, 133, 135-137 Thiersch graft in, 140-143 transcanal, 121-127, 128. Sir ahn

Transcanal approach, to external ear canal and middle ear.

histopathology of, 144-145 procedure on, 149-158 stenotic, canalplasty for, 151 tumors of, 151, 153, 754-155, 156, 157-15$

innervation of, 8, 9

External ear (Continued) vascular supply of, 7, 8

External otitis, intractable, canalplasty for, 151, 112

Facial canal, 17 facial nerve, avulsion of, complicating

translabyrinthine approach for acoustic -neuromas, 337

chorda tympanic branch of, 16 decompression of, transmastoid, 58, 60-67 histopathology of, 324 in temporal bone, 17 paralysis of, complicating suppurative otitis

media, 192, 194 surgery on, infratemporal, 315-324

myringotomy as, 315 middle cranial fossa approach to, 320-324 iranscanal approach to, 317, 379, 320 transmastoid approach to, 315-317, 318

trauma to, complicating simple mastoidectomy, 135

Facial recess approach, to cochlear implant, 54, 55-57. 58, 59

to posterior tympanotomy, 49, 52-53 , 54 Fallopian canal, 17 Fissula ante fenestram, 19 Fistula, perilymphatic, exploratory

tympanotomy for, 210-213 Footplate, floating, complicating total

stapedectomy with prosthesis, 260, 261 Foramen of Huschke, 3 Foramen singulare, 21 Foraminifcrous spiral tract, 2] Foreign body reaction, in operating room

104-105 Fossa of incus, 10 Fossub fenestrae cochleae, 10 Fossula fenestrae vestibuli, 10 Fossula post fenestram, 19 Fragments, depressed, complicating total

stapedectomy with prosthesis, 260. 261

Gelfoani, for ossicular chain grafting, 222-227 Geniculate ganglion, 19 Glomus jugulare tumors, infralahyrinthine,

infratemporal approach to, 327-331 Glomus tympanicum tumors, 325-327 Glossopharyngeal nerve, tympanic branch of,

14 Clues, for ossicular chain grafting, 223 Graft(s), harvesting of, for total stapedectomy

with prosthesis, 249, 252. 253 Thiersch, 140-141 tympanoplasty, classification of, 219 underlay, of tympanic membrane, 62, 63, 64

Grafting, of ossicular chain, 220, 222-223 of tympanic membrane, 220, 221

Granulation tissue, debridement of, from mastoid cavity, for Thiersch graft, 141-143

Granuloma, cholesterol, of medial petrous apex, MR imaging of, 3.3

Hair l i o n

cells, of spiral organ, 21 ulus. 19

I n d e x 365

Hearing devices, bone conduction, surgical approach for, 281-285

aims of, 281 complications of, 285 procedure for, 281, 283-284. 285

Helicotrema, of osseous labyrinth, 19 Helix, spine and tail of, 4 Hematoma of pinna, plastic surgery for, 342,

343-344 Histology, 23-27 Hypotympanic cells, 17

Implant, cochlear, 75, 82, 83-84 facial recess approach to, 54 , 55-5S, 59

IncudomaUeal joint, 12 Incus, anatomy of, 12, 13

dislocation of, complicating simple mastoidectomy, 137

complicating total stapedectomy with prosthesis, 257, 259

lesions of, tympanoplasty-ossiculoplasty for, 235, 239. 241

Incustapedial joint, 12 Informed consent, preoperative, 101-102 Infralabyrinthine, infratemporal approach to

glomus jugulare tumors of, 327-331 Inner ear, anatomy of, 17-22

nerves of, 21-22 sensorj' receptors of, 20-2] tumors of, 331-338 vascular supply of, 21

Innervation, of external ear, 8, 9 Instruments, for operating room, 105, 107, 109,

770-777

for temporal bone removal, 42, 43 Intact bridge mastoidectomy, 63, 67, 68 Intact-bridge tvmpanomastoidectomy (IBM),

for otitis media, 183, 185, 786-190 Intracranial abscess, complicating suppurative

otitis media, 194, 796 Intratemporal facial nerve surgery, 315-324

myringotomy as, 315 lontophoretic anesthesia, 102 Isthmus, 4 Iter chordae tympani posterior, 10

i

Jacobson's nerve, 14 Jugular bulb bleeding, complicating

translabyrinthine approach to acoustic neuromas, 337

Jugular foramen, chemodectoma of, MR imaging of, 32

Jugular wall, of middle ear, 9-10

K

Keloids, plastic surgery for, 341, 343

L

Labyrinth, of inner ear, 18 membranous, 19-20 osseous. 18-19

Labyrinthectomy, 71, 73, 74 -75 for incapacitating peripheral vertigo, 302,

305-306, 307, 308 transcanal, 82, 85. 86

Labyrinthine artery, 21 Labyrinthine vein, 21 Labyrinthine wall, of middle ear, 10 Labyrinthitis, complicating suppurative otitis

media, 194 Laceration of pinna. with tissue loss, plastic

surgery for, 345 without tissue loss, plastic surgery for, 344-

345 Laserfs), applications of, in middle ear,

276-278 for neurotology, 278-280 for ossicular problems, 276-278 for otologic surgery, 272 for stapedotomy, 273-276

Lidocaine, for anesthesia, 102 Ligament(s), annular, 12

auricle, 6 mallear, 12

Limbus, 19 Lop ears, plastic surgery for, 353, 354, 358

M

Maculae, 20 Magnetic resonance (MR) imaging, of temporal

bone, 28, 31-34 Malleal stria, of tympanic membrane, 6 Mallear ligaments, 12 Mallear prominence, of tympanic membrane,

6-7 Malleus, anatomy of, 12, 73

lesions of, tympanoplasty-ossiculoplasty for, 235, 236-238

Malleus-to-ova window prosthesis, for stapes fixation, 263, 266, 267

Mastoid air cells, 17 Mastoid cavitv, exteriorized, for otitis media,

191 granulation tissue from, debridement of, for

Thiersch grafts, 141-143 obliteration procedures for, for otitis media,

191-192, 193 skin graft of, 142, 143

Mastoid procedures, for otitis media, 177, 181, 185, 191

Mastoid wall, of middle ear, 10 Mastoidectomy, cortical, for otitis media, 181

intact bridge, 63, 67, 68 radical, 63, 67, 70, 71

modified, 63, 67, 69 for otitis media, 185, 191

simple, 44 -47, 48 as surgical approach, 133. 135-137

Mastoidectomy-tympanotomy approach, to cochlear Implant, 75, 82, 83-84

Mastoiditis, coalescent, complicating suppurative otitis media, 192

Mastoidotomy, 137-138 Mastoidotomy/tympanotomy, for cochlear

implants, 287, 292-296 Maxillary artery, branches of, 8 Meatoplasty, 138

in closed-cavity tympano-mastoldectomy, 140, 141

in open-cavity tympano-mastoidectomy, 138-140

Membranous labyrinth, 19-20 individual components of, 20

Membranous semicircular canals, 20

366 I n d e x

Membranous wall, of middle ear, 9 Meningitis, complicating suppurative otitis

media, 194 Meso tympanum, 27 Microscope, operating, 105, 107, 70S, 109 Middle cranial fossa approach, to

infratemporal facial nerve surgerv, 320-324 Middle ear, anatomy of, 8-17

approach to, endaural, 130-132 mastoidotomy as, 137-138 meatoplasty as, 138

closed-cavity tympano-mastoidcctornv as, 140, 141

open-cavitv tympano-mastoidcctornv as, 138-140'

postauricular, 132-133, 134 posterior tympanotomy as, 137 simple mastoidectomy in, 133, 135-137 Thiersch graft in, 140-143 transcanal, 121-127, 128. Sir also

Transcanal approach, to external ear canal and middle car.

auditory tube of, 12-14 dissection of, 75, 76-81 histopathology of, 144-145 laser applications in, 276-278 morphology of, 8 -10 , 11 mucosal lining of, 14 nerves of, 14-16 ossicles of, 10, 12, 13 tumors of, 325-331

glomus jugulare, 327-331 glomus tympanicum as, 325-327

vascular elements of, 14, 15 Middle fossa approach, to internal auditory

canal, 93, 95-96, 97 Modiolus, 19 Mondini's deformity, CI" imaging of, 29 Mucosal lining, of middle ear, 14 Muscle(s), of auricle, 6

Stapedius, 12 tensor tympani. 12

Myringoplasty, tvpe I l\ mp.iriopl.iMv and, 223-213

allograft in, lor total perloration. 233, 234 approach to, 223, 225. 226 for small central perforation, 225. 227-22$ overlay technique of, for central

perforation. 22^. 22lK 230 underlay graft in. Un large .interim

perforation, 230, 232. 231

for posterior perforation in atrophic membrane. 231). 231

Myringotomy and tubes, for otitis- media, 164-171

aim of, 164 complications of, 170-171 incisions for, 165, 166-167, 168 indications for, 164-165 instruments for, 165 tubes in, 168-170

for intratempora! facial nerve surgery, 315

N

Neoplasms of pinna, plastic surgery for, 347 349-353

Nerve(s), facial, decompression of, transmastoid, 58, 60-61

of externa] ear, 8, 9 Of inner ear, 21-22 of middle early, 14, 16

Neurectomy, singular, for incapacitating peripheral vertigo, 302, 304

lympanic, exploratory tympanotomy for, 211, 213, 214

Neuromas, acoustic, translabyrinthine approach lor, 331 -338. See also Translabyrinthine approach for acoustic neuromas.

Neurotology, lasers for, 278-280

O

Occipital artery, 14 Open-cavity tympano-mastoidectomy,

meatoplasty in, 138-140 Operating microscope. 105, 107, 108. 109 Operating room, 101-111. Sec a I fin Surgery,

equipment and procedures in, 102-111 foreign body reaction in, 104-105 instruments in, 105, 107, U0-1U positioning of surgical team in, 105, /06 record of operation in, 109, 111, 111-120 skin preparation in, 103-104 surgical time in, \ \ \

Operating room cards, for instruments and materials, 109

Organ of Corti, 20 Osseous labyrinth, 18-19 Osseous spiral lamina. 19 Ossicles, anatomy of, 10, 12, 13

for ossicular chain grafting, 222 laser applications in, 276-278 problems of, combined, tympanoplasty-

ossiculoplasty for, 240, 241, 243

Ossiculoplasty, 62, 63, 65-66 in tympanoplasty, 233, 235-243. S,v also

Tympanoplasty-ossiculoplasty. Otitis, external, intractable, canalplasty for,

m , 152 Otitis media. IM -2(N

cartilage Ivmpanopla-l\ loi atropine IVIUCMOIC membrane lor. 173 175, J7c

exleriuri/ed mastoid civilv lor, I9| lnsiop.uhology oh JW-20«î mastoid oblitération procedure lor 191-142

inaMoid procedure- in. 177. 1st. IS".. I'll m.iMoidei limn (>>i

u.rtie.il |K1 radical. I'M

modilied. 1X5, I'M mucoid, histopathology of. 199 myringotomy and tubes for. 164-171. Sec al<o

Myringotomy and tubes, for otitis media suppurative. Sec Suppurative otitis media. Iransmeatal permanent aeration tubes for,

171-173 tympanomastoid procedures in, 177

181-185; 186-190 tympanomastoidectomy for, closed-cavity,

181-183, 184 intact-bridge, 183, 185, 1S6-790

tympanoplasty for atelectatic tympanic membrane for, 175, 177, 17S-180

Otolithic membrane, 20 Otoliths, 20 Otologic evaluation, preoperative, 101 Otoplasty, 353-358 Oval window, 19

narrow, complicating total stapedectomy with prosthesis, 257, 259, 261

I n d e x 367

P

Pain, complicating total stapedectomy with prosthesis, 257

Paraganglioma, MR imaging of, 32 Paralysis, inlratemporal facial nerve, surgery

for, 315-324 myringotomy as, 315

Pars fiaccida, 7 Pars tensa, 7

Patient consent, preoperative, 101-102 Periauricular abscess, complicating suppurative

otitis media, 197, 198 Perilymphatic fistula, exploratory

tympanotomy for, 210-213 Periosteum, of osseous labyrinth, 19 Peripheral vertigo, incapacitating, surgery for,

297-314 Petrosal artery, superficial, 14 Petrosal nerve, lesser, 16 Petrositis, complicating suppurative otitis

media, 194, 195 Petrotympanic sutures, 3 Petrous apex, cells of, 17

medial, cholesterol granuloma, MR imaging of, 33

Petrous drainage, 71, 72 Petrous portion, of external ear, 3 Phalangeal cells, 20 Pharyngotympanic tube, 12, 14 Plastic surgery of pinna, 339-358

for amputation of pinna, total, 345-347, 348 for cleft car lobe, 339-341, 342 for congenital malformations, 353-358 for hematoma, 342, 343-344 for keloids, 341, 343 for laceration

with tissue loss, 345 without tissue loss, 344-345

for neoplasms, 347, 349-353 Plastics, for ossicular chain grafting. 222 Plastipore. for ossicular chain grafting. 222 Pneumati/ation, of temporal bone, lh-17 Portmann technique, for Iransmeatal

permanent aeration lube insertion, 171, 172

I'osljuncular approach, to external ear canal and middle ear, 132-133, 134

Preoperative otologic evaluation, 101 Prominence, of facial canal, Ul

ut lateral semicircular canal, 10 Prominent ears, plastic surgery for, 353,

355-357. 358 Promontory of middle ear, 8

prominent, complicating total stapedectomy with prosthesis, 257, 259

Prosthesis, malleus-to-oval window, for stapes fixation, 263, 266, 267

partial ossicular replacement, for malleus

lesion, 235 total ossicular replacement, for combined

ossicular problems, 240, 241-243 total stapedectomy with, 249-261. Sec also

Stapedectomy, total, with prosthesis. Pyramidal eminence, of middle ear, 10

R

Radical mastoidectomy, modified, 63, 67, 69 Record of operation, 109, 111, 711-120

Rctrolabyrinthine approach, to cerebellopontine angle, 82, 85, 87, 88

and vestibular nerve sectioning, for incapacitating peripheral vertigo, 307, 309, 310-311

Round window, 19 Round window niche, of middle ear, 10

Saccular duct, 20 Saccule, 20

procedures on, for incapacitating peripheral vertigo, 302, 303

Scala tympani, 19 Scala vestibuli, 19 Schuknecht's method, of temporal bone

removal, 39, 40-41, 43 Schwannoma, acoustic, intracanalicular CT and

MR imaging of, 37 seventh nerve, MR imaging of, 34

Scutum, 9 Semicanal, for tensor tympani muscle, 10 Semicircular canals, drilling of, complicating

simple mastoidectomy, 137 membranous, 20 of osseous labyrinth, 18-19

Sensory receptors, of inner ear, 20-21 Sigmoid sinus, damage to, complicating simple

mastoidectomy, 137 thrombophlebitis of, complicating

suppurative otitis media, 194, 196-197, 198 Silastic for ossicular chain grafting, 222 Sinus, bleeding in, complicating

translabyrinthine approach for acoustic neuromas, 337

posterior, of middle ear, 10 Skin grafts, for tympanic membrane, 220, 221

preparation of, in operating room, 103-104 thin, harvesting, for Thiersch grafts, 142, 143

Skull bone, transcochlear approach to, 90, 92, 93. 94

Spherical recess, of osseous labyrinth, 18 Spine of helix, 4 Spiral ganglion, 22 Spiral ligament, of osseous labyrinth, 19 Spiral organ, 20 Spiral sulcus, internal, of osseous labyrinth, 19 Squamolympanic sutures, 3 Squamous portion, of external ear, 3 Stapedectomy, harvesting, grafts in, 249, 252,

253 making prosthesis in, 253, 254-255 problems and variations during, 257,

259-260, 261 procedure in, 253, 256, 257, 258 total, with prosthesis, 249-261

Stapedius muscle, 12 Stapedotomy, 261

laser. 273-276 Stapes, anatomy of, 12, 73

fixation of, in obliterative otosclerosis, 261, 262

interposition procedure for, 261, 263, 264 malleus-to-oval window prosthesis for,

263, 266, 267 stapedotomy for, 261 surgery for, 247-271 total stapedectomy with prosthesis for,

249-261. Sec also Stapedectomy, total, with prosthesis,

histopathology of, 268-271 lesions of, tympanoplasty-ossiculoplasty for,

240, 241

368 I n d e x

Stapes footplate, 25 Stapes interposition, 261, 263, 264 Statoacoustic nerve, 21 Statoconic membrane, 20 Stenotic canal, canalplasty for, 15] Stria vascularis, 20

Stylomastoid branch, of posterior auricular artery, 8, 14

Subiculum, of middle ear, 10 Suction, in operating room, 107, 109 Suppurative otitis media, complications of

coalescent mastoiditis as, 192 facial nerve paralysis as, 192, 194 intracranial abscess as, 194, 196 labyrinthitis as, 194 meningitis as, 194 periauricular abscess as, 197, 198 petrositis as, 194, 195 sigmoid sinus thrombophlebitis as, 194,

•796-197, 198 surgery for, 192, 194-198

Suprameatal spine, 3 Suprameatal triangle, 3 Surgery, anesthesia for, 102

antibiotics for, 102 evaluation for, 101 patient consent for, 101-102 record of, 109, 111, 717-720

Surgical team, positioning of, in operating room, 105, 106

Surgical time, in operating room, 11]

T

Tail of helix, 4 Tectorial membrane, 20 Teflon, for ossicular chain grafting, 222 Tegmen tympani, 9 Tegmental wall, of middle ear, 9 Temporal bone, dissection of, 37-97

procedures for, 44-97 canalplasty as, 59, 62, 63 cochlear implants as, 54, 55-55 , 59, 75.

82, 83-S4

endolymphatic sac surgery as, 47, 49, 50-57

facial recess approach to posterior tympanotomy as. 49, 52-53, >-l

intact bridge mastoidectomy as, 63, 67, 68

labyrinthectomy as, 71, 73 . 74 -75 middle ear dissection as. 75, 76-81 middle fossa approach to internal

auditor,' canal as, 93, 95-96, 97 ossiculoplasty as, 62, 63, 65-66 petrous drainage as, 71, 72 radical mastoidectomy as, 63, 67, 70, 71

modified, 63, 67, 69 retrolabyrinthine approach to

cerebellopontine angle as, 82, 85, 87, 88

Simple mastoidectomy as, 44-47, 48 transcanal'labyrinthectomy as, 82, 85, 86 transcochlear approach to skull bone as,

90, 92, 93, 94 translabyrinthine approach to internal

auditory canal as. 87, 89, 90, 91 transmastoid facial nerve decompression

as, 59, 60-67 underlay graft of tympanic membrane

as, 62, 63, 64 facial nerve in, 17

Temporal bone (Continual) histology of, 2 3 r 2 7 imaging of

by computed tomography, 28, 29-31, 34 by magnetic resonance, 28, 37-34 high resolution, 28-35

paraganglioma of, MR imaging of, 32 pneumatizaHon of, 16-17 removal of, 39-43 resection of, subtotal, 153, 755, 156

total, 136, 157-75S Tensor tympanic muscle, 12 Terminal incisure, 4 Thiersch graft, 140-143

debridement of granulation tissue from mastoid cavity for, 141-143

harvesting thin skin for, 742, 143 of mastoid cavity, 142, 143

Thrombophlebitis, sigmoid sinus, complicating suppurative otitis media, 194, 196-197, 198

Tissue adhesions, for ossicular chain grafting, 223

Transcanal approach, to external ear canal and middle car, 121-127, 128

closure in, 125 I evaluation of flaps in, 123, 124, 125 exposure of middle ear in, 125, 726 highlights of, 121 incisions in. 123, 124 injection of local anesthetic in, 123, 724 inspection and cleansing in, 121, 123 packing in, 127, 728 pitfalls in, 121 revisions in, 125, 127

to intra temporal facial nerve surgery, 317, 379, 320

to labyrinthectomy, for incapacitating peripheral vertigo, 302, 306

Transcanal labyrinthectomy, 82, 85. 86 Transcochlear approach, to skull bone, 90, 92,

93, 94 Translabyrinthine approach, to acoustic

neuromas, 331-338 aim of, 331 highlights of, 331 intraoperative complications or problems

with, 337-338 pitfalls of, 331 procedure for, 331-337

to internal auditory canal, 87, 89, 90, 9? Transmastoid approach, to infratemporal facial

nerve surgery, 315-317, 378 to labyrinthectomy, for incapacitating

peripheral vertigo, 307, 308 Transmastoid labyrinthine dissection, 71, 73,

74-75

Transmeatal permanent aeration tubes, for otitis media, 171-173

Transmoid facial nerve decompression, 59, 60-61

Transverse crest of fundus, 21 Trigeminal nerve, auriculotemporal branch of,

8 Tumor(s), external auditory canal, 151, 153,

754-155, 156. 757-758' inner ear, 331-338 middle ear, 325-331

glomus tympanicum, 325-327 glomus jugulare, 327-331

of pinna, total, plastic surgerv for, 347, 349-353

Tympanic artery. 14