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27th Annual Meetingof the AANS/CNS Section onDisorders of the Spine andPeripheral Nerves

March 9-12, 2011JW Marriott Desert Ridge

Phoenix, Arizona

Scientific Program

Evidence-Based Spine Surgery in the Real World

Save the Date!

2012 ANNUAL MEETING OF

THE AANS/CNS SECTION ONDISORDERS OF THE SPINE AND

PERIPHERAL NERVES

March 7-10, 2012The Walt Disney World

Swan and Dolphin ResortOrlando, Florida

27thAnnual M

eeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves SCIENTIFIC PROGRAM

11DSPN_SP_Cover_F021811:Cover 2/22/11 4:59 PM

PROGRAM AT-A-GLANCE

WEDNESDAYMARCH 9, 2011

8:00 AM – 6:00 PMRegistrationGrand Canyon Foyer

8:00 AM – 6:00 PMSpeaker Ready RoomPinnacle Peak 3

1:30 – 5:30 PMPediatric Craniocervical Society Desert Conference Suite III

Special Course I – Coding Update and ReviewGrand Canyon 9

Special Course II – Masters in Spinal Surgery: WhatHas Experience Taught Me?Grand Canyon 10

Special Course III – Spinal DeformityGrand Canyon 11

Special Course IV – Advanced MISTechniques/Managing MISComplicationsDesert Conference Suite IV

Special Course V – Management of PerioperativePainGrand Canyon 13

Special Course VI – Update on Spinal Surgery inTurkeyGrand Canyon 12

Special Course VII – Cervical MyelopathyDesert Conference Suite VIII

6:00 – 8:00 PMOpening ReceptionSage Court

THURSDAYMARCH 10, 2011



6:30 – 7:00 AMContinental BreakfastGrand Saguaro Foyer

6:30 – 6:55 AMCase Presentations Grand Saguaro North

7:00 – 9:30 AMScientific Session I – Evidence-Based Spine Surgery inthe Real WorldGrand Saguaro North

9:00 AM – 7:00 PMExhibit Hall Open and PosterViewingGrand Canyon Ballroom

9:30 – 10:15 AMBeverage Break and What’s NewSession IGrand Canyon Ballroom

10:15 AM – 12:30 PMOral Platform Presentations IGrand Saguaro North

12:30 – 1:25 PMLunch and What’s New Session IIGrand Canyon Ballroom

1:30 – 3:00 PMScientific Session II – Spinal Surgery ComplicationAvoidance and ManagementGrand Saguaro North

3:00 – 3:45 PMBeverage Break and What’s NewSession IIIGrand Canyon Ballroom

3:45 – 5:15 PMOral Poster Presentations IGrand Saguaro North

Oral Poster Presentations IIGrand Canyon 9

5:15 – 6:45 PMReception in the Exhibit HallGrand Canyon Ballroom

FRIDAYMARCH 11, 2011





7:00 – 9:00 AMScientific Session III – Evolution of Treatment forMetastatic DiseaseGrand Saguaro North

9:00 – 9:30 AMMayfield Awards andPresentationsGrand Saguaro North

9:00 AM – 12:00 NoonExhibit Hall Open and PosterViewingGrand Canyon Ballroom

9:30 – 10:15 AMBeverage Break and What’s NewSession IVGrand Canyon Ballroom

10:15 AM – 12:15 PMOral Platform Presentations IIGrand Saguaro North

12:20 – 12:30 PMAnnual Business MeetingGrand Saguaro North

12:30 – 2:30 PMLuncheon Symposium I – Revision Spine SurgeryGrand Canyon 9

Luncheon Symposium II –Neurosurgeon as CEO: BusinessAspects of Spinal SurgeryGrand Canyon 10

Luncheon Symposium III – Cranial-Cervical JunctionGrand Canyon 11

Luncheon Symposium IV – Geriatric SpineGrand Canyon 12

Luncheon Symposium V – Spinal ArthroplastyGrand Canyon 13

1:30 – 5:30 PMSpecial Course VIII – Peripheral Nerve Exposures andNerve Repair TechniquesDesert Conference Suite III

Special Course IX – Evaluation and Management ofthe Spine Trauma PatientDesert Conference Suite IV

SATURDAYMARCH 12, 2011





6:55 – 8:15 AMOral Posters Presentations III Grand Saguaro North

8:20 – 9:40 AMDavid Cahill MemorialControversies SessionGrand Saguaro North


9:40 – 10:25 AMBeverage BreakGrand Canyon Ballroom

10:25 – 11:05 AMFellowship Awards and UpdatesGrand Saguaro North

11:05 AM – 12:35 PMOral Posters Presentations IVGrand Saguaro North

Special Thanksto These Companies for Providing an Educational Grant in Support of the 2011 Annual Meeting!

NEUROSURGICAL EDUCATION AMBASSADOR:

NEUROSURGICAL LEADERSHIP AMBASSADOR:

FUTURE NEUROSURGERY AMBASSADOR:

RESIDENT EDUCATION PARTNER:

ANNUAL MEETING SUPPORTERS:

as of February 23, 2011

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March 9-12, 2011 JW Marriott Desert Ridge, Phoenix, Arizona

TABLE OF CONTENTS 1

PROGRAM AT–A–GLANCE Inside Cover

WELCOME

2011 ANNUAL MEETING COMMITTEES

CHAIRMAN’S BIOGRAPHY

AWARDS AND FELLOWSHIPS

CURRENT AND PAST OFFICERS

PAST PROGRAM COMMITTEES

CME CREDIT & GENERAL INFORMATION

DISCLOSURE LISTING

MEETING AGENDA

Wednesday, March 9

Thursday, March 10

Friday, March 11

Saturday, March 12

EXHIBITOR INFORMATION

ORAL PLATFORM ABSTRACTS

AWARDS PROGRAM ABSTRACTS

ORAL POSTER ABSTRACTS

DIGITAL POSTER ABSTRACTS

15

14

68

48

46

40

36

33

29

25

22

12

10

4

3

2

2

PURPOSE OF THE SPINE AND PERIPHERAL NERVES SECTION

To foster the use of spinal neurosurgical methods for the treatment of diseases of the spinal neural

elements, the spine and peripheral nerves. To advancespinal neurosurgery and related sciences, improve patientcare, support meaningful basic and clinical research,provide leadership in undergraduate and graduatecontinuing education, and promote administrativefacilities necessary to achieve these goals.

YOUR OPINION COUNTS!

A link to the online evaluations will be sent to the e-mail addressthat you used to register for the meeting. A link to the evaluationsystem will also be available at www.spinesection.org.

You will be able to login with either:

1. Your last name and the e-mail address where the link was sent.2. Your Annual Meeting badge number and your last name.

After logging in, simply follow the link to “Claim Credits”. Eachsession evaluation will be listed on this page. You will also be able tosubmit a request for CME credits at the same time, thoughsubmission of evaluations is not mandatory to receive CME credit.

Your feedback is critical in helping the AANS/CNS Section onDisorders of the Spine and Peripheral Nerves plan future educationand Annual Meetings.

PREVIOUS MEETINGS2010 Orlando, Florida2009 Phoenix, Arizona2008 Lake Buena Vista, Florida2007 Phoenix, Arizona2006 Lake Buena Vista, Florida2005 Phoenix, Arizona2004 San Diego, California2003 Wesley Chapel, Florida2002 Lake Buena Vista, Florida2001 Phoenix, Arizona2000 Rancho Mirage, California1999 Lake Buena Vista, Florida1998 Rancho Mirage, California

1997 Newport Beach, California1996 Lake Buena Vista, Florida1995 Phoenix, Arizona1994 Fort Lauderdale, Florida1993 Tucson, Arizona1992 Miami, Florida1991 Rancho Mirage, California1990 Captiva Island, Florida1989 Cancun, Mexico1988 Phoenix, Arizona1987 Boca Raton, Florida1986 San Diego, California1985 Greenleaf, Florida

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AANS/CNS Section on Disorders of the Spine and Peripheral Nerves

WELCOME2

Dear Colleague:

The AANS/CNS Section on Disorders of the Spine and Peripheral Nerveswelcomes you to the 2011 Annual Meeting here at the spectacular JW Marriott Desert Ridge. This year’s meeting will deliver maximumeducational value as we explore our timely theme, Evidence-Based SpineSurgery in the Real World.

Experts from the United States and across the globe will address severalcritical and controversial topics within spine and peripheral nerve surgeryand examine the impact of each on your practice. This year’s ScientificProgram Committee has created a truly outstanding program with nineSpecial Courses highlighting the latest techniques and strategies on manytopics including MIS techniques, current issues in spine coding, and spinaldeformity; five Luncheon Symposia covering critical business aspects ofspinal surgery to the management of the geriatric spine; and more than 240 Oral Platform, Oral Poster and Digital Poster abstracts. Our ScientificSessions will explore the evolution of treatment for metastatic disease,evidence-based medicine in the real world, and complication avoidance and management in spinal surgery.

Our Exhibit Hall will offer further opportunities for education with morethan 60 exhibitors displaying the latest advances and technology in the field!Visit with your corporate partners during daily breaks to learn more aboutthe products and services available to enhance and improve your practice.You won’t want to miss our daily What’s New sessions which will feature newand innovative products and/or technological services.

In addition to the outstanding education, you can also experience valuablenetworking events throughout the week allowing you to connect with bothyour colleagues and corporate contacts in a more relaxed atmosphere.Wednesday evening’s Opening Reception, and Thursday afternoon’s Lunchin the Exhibit Hall and Thursday evening’s Reception with the Exhibitors will provide sumptuous hors d’oeuvres and beverages while you networkwith colleagues from around the globe. Residents will also enjoy connectingwith other young neurosurgeons while viewing a special presentation by Dr. Robert F. Heary at the Young Neurosurgeons’ Dinner on Friday evening.

Thank you again for joining us in Phoenix for the 2011 Annual Meeting. Wehope you will take time to enjoy both the science and the scenery here at theJW Marriott Desert Ridge.

Sincerely,

2011 ANNUAL MEETING COMMITTEES

Annual Meeting ChairpersonPraveen V. Mummaneni

Scientific Program ChairpersonDaryl R. Fourney

Exhibit ChairpersonBrian R. Subach

2011 Scientific Abstract Review andScientific Advisory Committee Peter D. AngevineCarlos BagleyAli BydonJohn ChiDean ChouSanjay S. DhallDaryl R. FourneyOren N. GottfriedJames S. HarropRobert F. HearyLangston T. HollyPatrick C. HsiehAdam S. KanterDean KarahaliosYevgeniy A. KhavkinFrank La MarcaMatthew J. McGirtPraveen V. MummaneniIbrahim OmeisDaniel M. SciubbaJustin S. SmithRobert J. SpinnerMichael P. SteinmetzEve C. TsaiJamie S. UllmanMarjorie WangMichael Y. WangTimothy F. WithamJean-Paul WolinskyLynda Jun-SanYang

2011 Poster Awards and Grading CommitteeDaryl R. FourneyAdam S. KanterDaniel M. SciubbaMarjorie C. Wang

Ziya L. Gokaslan, MD, FACSChairman

Daryl R. Fourney, MDScientific Program Chairperson

Praveen V. Mummaneni, MDAnnual Meeting Chairperson



CHAIRMAN’S BIOGRAPHY 3

PRESIDENTIALADDRESS

Evolution of Surgical Treatment

THURSDAY, MARCH 10, 8:50 AMGRAND SAGUARO NORTH

Ziya L. Gokaslan, MD, FACSDonlin M. Long ProfessorProfessor of Neurosurgery, Oncology, and Orthopaedic SurgeryVice-Chairman – Department of NeurosurgeryDirector – Neurosurgical Spine ProgramJohns Hopkins University School of Medicine

ZIYA L. GOKASLAN, MD, FACS,was born on April 7, 1959 in Washington, DC (USA).He later returned to Turkey with his family where he completed his medical education atthe Medical Faculty of Istanbul University. In 1984, Dr. Gokaslan returned to the US andworked as the Clinical Director of Sleep Disorders Center of the Department of Psychiatry

for 1½ years. He then entered General Surgery Residency under Dr. Michael E. DeBakey in 1985.After one year of internship, he joined the Department of Neurosurgery at Baylor College ofMedicine as Clinical Neurotrauma Research Fellow. In 1988, he became a Neurosurgery Residentunder Dr. Robert G. Grossman and completed his training in 1993 at the Baylor College ofMedicine in Houston. He was then accepted into the Neurosurgery/Orthopaedic Spine Surgery

Fellowship Training under Drs. Paul Cooper and Thomas Errico at the New York University Medical Center in New York. After thecompletion of his Fellowship Training in Spinal Surgery, Dr. Gokaslan returned to Houston and joined the Department ofNeurosurgery faculty as Assistant Professor at the University of Texas, MD Anderson Cancer Center under Dr. Raymond Sawaya. Thisis where Dr. Gokaslan specialized in the surgical treatment of spinal neoplasms, published extensively on the topic and developednovel surgical approaches in managing these tumors.

In 2000, Dr. Gokaslan became the Director of Neurosurgical Spinal Oncology Section and, in 2002, was appointed Deputy Chairmanof the Department of Neurosurgery and promoted to Associate Professor. In 2002, Dr. Gokaslan was recruited to Johns HopkinsUniversity, Department of Neurosurgery and became the Director of the Spine Division, Vice-Chairman, and Professor ofNeurosurgery, Oncology, and Orthopaedic Surgery under Dr. Henry Brem. Later that year, he was awarded the Donlin M. LongProfessorship at Johns Hopkins.

Dr. Gokaslan’s clinical practice focuses on the radical surgical treatment of both primary and metastatic spinal tumors, sacralneoplasms and spinal cord tumors. He developed many novel approaches for resection of pancoast tumors, spinal neoplasms, as wellas sacral tumors, including total sacrectomy and complex spinal and pelvic reconstruction.

His basic research focuses on the development of new animal models to study the pathophysiology of neoplastic spinal cordcompression and to define the roles of proteolytic enzymes in tumor invasion and to devise novel therapeutic approaches to spinaltumors.

He has authored over 200 peer-reviewed papers and has presented over 150 national and international lectures since 1996. He wasvoted one of the Best Doctors in America in 2005 and garnered Baltimore Magazine’s Top Doctors recognition in 2007. He serves onthe editorial boards of top academic journals, including Journal of Spinal Disorders & Techniques, The Spine Journal, Journal ofNeurosurgery: Spine, The European Spine Journal, Nature Reviews in Neurology, Journal of Surgical Oncology, and World Neurosurgery.He is currently the Chairperson of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves.

He is a member of numerous prestigious societies, notably the Society of Neurological Surgeons since 2007, Cervical Spine ResearchSociety since 2003, American Society of Clinical Oncology since 2001, American Association of Neurological Surgeons since 1998,Congress of Neurological Surgeons since 1997, and the North American Spine Society since 1994.



MERITORIOUS SERVICE AWARD4

Meritorious Service Award Recipients1990 – 20102010 Regis W. Haid, Jr. 2009 Paul C. McCormick2008 Ronald I. Apfelbaum2007 David L. Kelly, Jr.2006 John A. Jane, Sr.2005 Ulrich Batzdorf2004 Russell W. Hardy, Jr.2003 Edward C. Benzel2002 No Award Presented2001 Stewart B. Dunsker2000 Arnold H. Menezes1999 Volker K. H. Sonntag1998 Russell L. Travis1997 David G. Kline1996 No Award Presented1995 No Award Presented1994 Sanford J. Larson1993 Joseph A. Epstein1992 Charles A. Fager1991 Frank H. Mayfield1990 Ralph B. Cloward

AwardsOn pages 5-9 general informationregarding section sponsored researchand fellowship awards is listed. Formore information, visit the AANS/CNSSection on Disorders of the Spine andPeripheral Nerves web site at:www.spinesection.org

Research FundingThe AANS/CNS Section on Disorders ofthe Spine and Peripheral Nerves hasestablished three Research Grants.Depending upon the quality of theaward submissions, there may be oneaward in each category annually.

Paul R. Cooper, MD2011 Meritorious Service Award Recipient

PAUL R. COOPER, MD, received his BAfrom Columbia in 1962, completed his MDdegree at the University of Virginia in 1966followed by an internship and a year of

residency in general surgery at the UniversityHospitals of Cleveland. He subsequently served asa Medical Officer in the United States Navy aboardthe USS Wright and at the Naval Air Station inNorfolk, Virginia. Following military service hecompleted a residency in neurosurgery at The NewYork University Medical Center in 1975.

He began his academic career as AssistantProfessor in the Division of Neurosurgery, University of Texas – Southwestern MedicalSchool and was subsequently appointed Associate Professor in the Department ofNeurosurgery, State University of New York – Downstate Medical Center. He returned toNew York University Medical Center in 1981 as Associate Professor of Neurosurgery andDirector of the Neurosurgery Spine Fellowship Program. He was subsequently namedthe Attilio & Olympia Ricciardi Professor of Neurosurgery at New York University Schoolof Medicine, and Professor of Orthopedic Surgery, positions he held through 2007. Asdirector of the spine fellowship program, the highlight of his academic career wastraining over fifteen superb spine surgeons, many of whom are attending this meeting.

Dr. Cooper was active in both international and local societies, including the Academyof Neurological Surgeons, Society of Neurological Surgeons, Congress of NeurologicalSurgeons, the American Association of Neurological Surgeons and the Société deNeurochirurgie de Langue Française. He served as President of the Cervical SpineResearch Society from 2002 to 2003. Dr. Cooper has held editorial positions forNEUROSURGERY® and Spine, and has served as an ad hoc reviewer for the NewEngland Journal of Medicine.

In addition to his academic and clinical responsibilities, Dr. Cooper has written over 140articles and book chapters. He has edited a number of books on head injury, themanagement of post-traumatic spinal instability, contemporary diagnosis andmanagement of pituitary adenomas, and degenerative disease of the cervical spine. In1996, he co-authored The Practice of Neurosurgerywith Drs. George Tindall and DanielBarrow.

Since retiring from active practice in 2007 he has been able to spend more time with hisfamily, including two daughters and two grandchildren. He took the intensive course incuisine for culinary professionals at the Cordon Bleu in Paris which sharpened hiscooking skills, and spends an hour a day practicing the piano. At his country home inrural Massachusetts he tends a large organic garden, and raises sheep and chickens. Hehas been able to exercise a long passion for squash and bicycling. Weather permitting,he hikes and skis on the trails adjacent to his home. When the sun goes down, he is notaverse to pulling the cork on a bottle from his extensive wine cellar.



AWARDS AND FELLOWSHIPS 5

The Apfelbaum Award, sponsored by Aesculap, is for either basic or clinical research related to thespine with funding up to $15,000. This research award is intended to establish funding for researchrelated to the spine, and to provide a means of peer review for clinical research projects to helpimprove the quality of the proposal and therefore, enhance competitiveness for National Institutes ofHealth (NIH) funding. The award is also meant to create an annual funding mechanism to establishthe AANS/CNS Section on Disorders of the Spine and Peripheral Nerves as a known source for qualityclinical research aimed at answering questions pertaining to the treatment of disorders of the spineand peripheral nerves.

ZACHARY ADAM SMITH, MD

Zachary A. Smith, MD, completed his undergraduate degree as a Presidential Scholar fromDartmouth College and received his medical degree from the UCLA School of Medicine. In 2010,

he completed neurosurgical training at UCLA. During his neurosurgical training, he developed aspecific interest in minimally invasive surgical techniques in the spine while working under thementorship of Dr. Larry T. Khoo. As a recipient of the Apfelbaum Award, he will work under theguidance of Dr. Richard G. Fessler at Northwestern during his one-year clinical fellowship. Hisresearch award will support a biomechanical study titled, “Biomechanical Comparison of MinimallyInvasive Spinal Decompression vs. Open Lumbar Laminectomy.”

The Kline Award, sponsored by Integra Foundation, is for either basic or clinical research related toperipheral nerves with funding up to $15,000. This research award is intended to establish funding forresearch related to the peripheral nerves, and to provide a means of peer review for clinical researchprojects to help improve the quality of the proposal and therefore, enhance competitiveness for NationalInstitutes of Health (NIH) funding. The award is also meant to create an annual funding mechanism toestablish the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves as a known source forquality clinical research aimed at answering questions pertaining to the treatment of disorders of thespine and peripheral nerves.

JACOB D. ALANT, MBCHB, MMED, FRCS(C)

Jacob D. Alant, MBChB, Mmed, FRCS(C), received his medical degree in 1997 and completed hisneurosurgical residency in 2006 at the University of Pretoria in South Africa. He completed a

Peripheral Nerve Surgery Fellowship with Dr. Rajiv Midha in Calgary, Canada from 2008-2009 andearned his FRCS(C) in 2009. From 2009-2010, he completed a Combined Spine Surgery Fellowship inCalgary.

Dr. Alant is currently working on his Masters of Science in Neurosciences at the University of Calgaryand is working to further characterize and validate their novel experimental traumatic neuroma-in-continuity injury model.

DAVID KLINERESEARCH AWARD

Past David Kline Research Award Recipient:

2010 – Gerald Tuite, MD

RONALD I. APFELBAUMRESEARCH AWARD

Past Ronald I. ApfelbaumResearch Award Recipient: 2010 – John H. Shin, MD



AWARDS AND FELLOWSHIPS6

The Larson Award, sponsored by DePuy Spine, is limited to clinical research with funding up to$30,000. This research award is intended to establish funding for clinically relevant research relatedto the spine and peripheral nerves, and to provide a means of peer review for clinical researchprojects to help improve the quality of the proposal and therefore, enhance competitiveness forNational Institutes of Health (NIH) funding. The award is also meant to create an annual fundingmechanism to establish the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves as aknown source for quality clinical research aimed at answering questions pertaining to the treatmentof disorders of the spine and peripheral nerves.

ERICA F. BISSON, MD

Erica F. Bisson, MD, completed her neurosurgical training at the University of Vermont and is agraduate of the Tufts University School of Medicine. Additionally, she completed a fellowship in

spine surgery at the University of Utah under the guidance of Dr. Ronald Apfelbaum. She joined theDepartment of Neurosurgery at the University of Utah in 2009, specializing in complex spine surgerywith a clinical and academic emphasis on occipitocervical disease.

Prior to returning to Utah, Dr. Bisson was Senior Staff in the Department of Neurosurgery at the LaheyClinic and Department of Surgery at Emerson Hospital. Currently, she is the principal investigator ona multicenter trial evaluating surgical approach in cervical spondylotic myelopathy.

The Cahill Fellowship, sponsored by Synthes, is awarded annually to one U.S. or Canadian trainedneurosurgical resident to provide supplemental funding for advanced education and research indisorders of the spine or peripheral nerves in the form of fellowship training away from their parentinstitution. The amount of the award is $30,000. Applicants should be residents in training or ABNSeligible fellows, must provide a letter of acceptance from the designated mentor and program, a letterof support from their training program director, a description of the proposed fellowship with theeducational or research goals, and a current CV.

TIMOTHY DAVID USCHOLD, MD

Timothy David Uschold, MD, is a PGY-5 senior resident at the Barrow Neurological Institute inPhoenix, Arizona. He graduated summa cum laude from Cornell University with an undergraduate

degree in biology (concentrating in neurobiology and behavior) in 2002. He obtained his MD fromDuke University School of Medicine in 2006. Dr. Uschold’s clinical and research interests includeoccipital-cervical junction injuries, spinal deformity, spinal trauma, minimally invasive techniques,and decision-making in spinal surgery. Under the auspices of the Cahill Fellowship, he will pursueadditional clinical training at Frenchay Hospital in Bristol, UK with Mr. Nitin Patel. He plans tointegrate his current work at the BNI with a larger multicenter evaluation of anterior vs. posteriorcervical approaches. He additionally aims to explore the socioeconomic factors affecting spine care intwo different health systems.

CAHILL FELLOWSHIP

Past Cahill Fellowship Recipient:

2010 – Chandan G. Reddy, MD

SANFORD LARSONRESEARCH AWARD

Past Sanford Larson ResearchAward Recipient:

2010 – Matthew J. McGirt, MD




The Cloward Fellowship, sponsored by Medtronic, is awarded annually to one U.S. or Canadian trainedneurosurgical resident to provide supplemental funding for advanced education and research indisorders of the spine or peripheral nerves in the form of fellowship training away from their parentinstitution. The amount of the award is $30,000. Applicants should be residents in training or ABNSeligible fellows, must provide a letter of acceptance from the designated mentor and program, a letter ofsupport from their training program director, a description of the proposed fellowship with theeducational or research goals, and a current CV.

MICHAEL J. DORSI, MD

Michael J. Dorsi, MD, completed his medical degree at Johns Hopkins School of Medicine inBaltimore and will graduate from its neurosurgery program in 2011. Over the past two years he

completed a research fellowship at UCLA sponsored by the California Institute for RegenerativeMedicine studying intraspinal stem cell transplantation following ventral root avulsion. He will joinDr. Langston Holly for a twelve-month spine surgery fellowship at UCLA. The Cloward Fellowship willsupport his research work on animal models of cervical myelopathy. Dr. Dorsi plans to establish afuture practice focused on complex peripheral nerve and minimally invasive spine surgery.

The Sonntag International Fellowship, sponsored by Medtronic, is awarded annually to aneurosurgical resident or neurosurgeon from outside of the U.S. or Canada to provide supplementalfunding for advanced education and research in disorders of the spine in the form of a fellowshipexperience in the United States or Canada. The amount of each award is $5,000. Applicants mustprovide a letter of acceptance from the designated mentor and program, a letter of support fromtheir training program director if applicable, a description of the proposed fellowship with theeducational or research goals, and a current CV.

GURPREET SINGH GANDHOKE, MD

Gurpreet Singh Gandhoke, MD, completed his medical school training at the Pune University inIndia and completed a three year residency training in general surgery from the Byramjee

Jeejeebhoy Medical College. He then went on to complete his neurosurgery residency training at theKing George’s Medical University in India where he won the gold medal for being the best outgoingstudent during both his residency training programs. While still in training, Dr. Gandhoke published11 scientific papers – one, published in the British Journal of Neurosurgery, describes a new techniqueto treat long segment spinal extradural arachnoid cysts in the pediatric population.

Dr. Gandhoke is currently a research fellow with Dr. Peter Nakaji at the Barrow Neurological Institutein Phoenix, Arizona, and is contributing to two neurosurgical atlases, book chapters and researchpapers. Dr. Gandhoke is now looking forward to expand his skills in treating spinal disorders bypursuing an observership with Dr. Praveen V. Mummaneni at the University of California, San Francisco.

During his free time, Dr. Gandhoke enjoys playing the guitar.

SONNTAG INTERNATIONAL

FELLOWSHIP

Past Sonntag InternationalFellowship Recipient:

2010 – Payman Vahedi, MD

CLOWARDFELLOWSHIP

Past Cloward FellowshipRecipient:

2010 – Helene T. Khuong, MD



AWARDS AND FELLOWSHIPS8

The Outcomes Committee Award is presented annually by the AANS/CNS Section on Disorders of theSpine and Peripheral Nerves to a neurosurgical resident or BC/BE neurosurgeon in North Americawho authors an outstanding abstract presenting the results of a clinical investigation in the area ofspine or peripheral nerve disorders, that demonstrates sound methodological design and includesevaluation of patient-oriented outcomes as the primary endpoint. The recipient of the award will beselected by the members of the AANS/CNS Section on Disorders of the Spine and Peripheral NervesOutcomes Committee. The award is gift from The David and Jean Wallace Fund. The recipient willreceive a $2,000 honorarium to help cover the expenses of attendance at the AANS/CNS Section onDisorders of the Spine and Peripheral Nerves Annual Meeting. Abstracts to be considered should beidentified on the Annual Meeting abstract submission form and submitted prior to the deadline.

CHEERAG D. UPADHYAYA, MD, MS

Cheerag D. Upadhyaya, MD, MS, graduated from the neurosurgery residency at University ofMichigan. Dr. Upadhyaya received his BS degree from Emory University and his MD from the

University of Florida College of Medicine. He completed a fellowship with Dr. Praveen V. Mummaneniat the University of California San Francisco.

Friday, March 11, 9:20 – 9:28 AMAnalysis of the Three United States FDA-IDE Cervical Arthroplasty TrialsCheerag Upadhyaya, Jau-Ching Wu, Regis W. Haid, Jr., Vincent C. Traynelis, Bobby Tay, Domagoj Coric,Gregory R. Trost, Scott A. Meyer, Praveen V. Mummaneni

The Mayfield Awards are presented annually by the AANS/CNS Section on Disorders of the Spine andPeripheral Nerves to neurosurgical residents or BC/BE fellows in North American training programswho author the outstanding manuscripts detailing a laboratory or clinical investigation in the area ofspinal or peripheral nerve disorders. This award is also applicable to individuals in DO trainingprograms. The manuscript for this award is presented by attaching related information to their abstractduring the abstract submission process. Two awards are available, one for clinical research and one forbasic science research. Each recipient will receive a $1,000 cash award and an honorarium up to $2,000to cover the expenses of attendance at the Annual Meeting of the AANS/CNS Section on Disorders of theSpine and Peripheral Nerves. Abstracts to be considered for the Mayfield Award should be identified assuch on the Annual Meeting abstract submission form and submitted prior to deadline.rographi.

MAYFIELD AWARDS

2011 OUTCOMESCOMMITTEE AWARD

Past Outcomes CommitteeAward Recipient:

2010 – Daniel C. Lu, MD

Mayfield Award Recipients 1984 - 2010

2010 Basic Science: Wilson Zachary RayClinical Science: Raqeeb Haque

2009 Basic Science: Daniel L. MasterClinical Science: Matthew B. Maserati

2008 Basic Science: Ann Margaret ParrClinical Science: Dennis E. Cramer, Matthew M. Kang

2007 Basic Science: Sharad RajpalClinical Science: Florian Roser

2006 Basic Science: Toshitaka SekiClinical Science: Benson Yang

2005 Basic Science: John Y. K. LeeClinical Science: Nicholas H. Post

2004 Basic Science: Bryan B. BarnesClinical Science: Michael Y. Wang

2003 No Awards Presented

2002 Basic Science: Edward R. SmithClinical Science: Ketan R. Bulsara

2001 Basic Science: Ketan R. BulsaraClinical Science: Gordon W. Tang

2000 Basic Science: Neill M. WrightClinical Science: Viswanathan Rajaraman

1999 Basic Science: Steven CashaClinical Science: Nicholas Theodore

1998 Tord D. Alden

1997 Michael A. Morone

1996 Basic Science: Paul C. FrancelClinical Science: Paul D. Sawin

1995 Simcha J. Weller

1994 Timothy C. Ryken

1993 Basic Science: Allan D. LeviClinical Science: Gerald F. Tuite

1992 Rajiv Midha

1991 Peter G. Gianaris

1990 R. John Hurlbert

1989 Richard K. Simpson, Jr.

1988 No Award Presented

1987 John A. Feldenzer

1986 No Award Presented

1985 Abhijit Guha

1984 Mark N. Hadley




MOHAMMED F. SHAMJI, MD

Mohammed F. Shamji, MD, is the chief resident of neurosurgery at The Ottawa Hospital in Ottawa,Canada. Dr. Shamji completed combined BS/MS degrees in chemistry at Yale University, his MD

training at Queen’s University, and is finishing his neurosurgical residency at The Ottawa Hospital.Mid-residency, he completed PhD training in Biomedical Engineering at Duke University withprojects focusing on animal models of inflammatory radiculopathy and sustained-release drugdelivery. He is husband to his devoted wife, father to two lovely daughters, and spends his spare timefeeding his endurance running habit. His academic interests include spine surgery andpathomechanisms of low back pain with career aspirations of evolving into a surgeon-scientist.

Friday, March 11, 9:00 – 9:08 AMEvidence of Descending Supraspinal Control of Nociception and Pain Behavior in Experimental Disc-Herniation RadiculopathyMohammed F. Shamji, Priscilla Hwang, Kyle D Allen, Mosfata Gabr, J. Chen, Liufang Jing, William J. Richardson, Lori A. Setton

TYLER J. KENNING, MD

Tyler J. Kenning, MD, is currently a sixth-year neurosurgery resident at Albany Medical Center. Aftercompleting his undergraduate degree in biology from Washington and Lee University, Dr. Kenning

attended Jefferson Medical College. During residency, he conducted stem cell research for spinal cordinjury in conjunction with Sally Temple, PhD, of the New York Neural Stem Cell Institute. In additionto the Mayfield Clinical Science Award, he was recently the recipient of the 2010 CNS/Karl StorzEndoscopy Fellowship. Upon completion of his residency, he will be conducting a fellowship inendoscopic skull base surgery with Dr. James Evans at Thomas Jefferson University Hospital.

Friday, March 11, 9:10 – 9:18 AMPerioperative Use of Dexamethasone in Multilevel Anterior Cervical Spine Surgery: Preliminary Resultsof a Prospective, Randomized, Double-Blinded TrialTyler J. Kenning, Karen Petronis, John W. German, Doniel Drazin, Darryl J. Dirisio

2011 MAYFIELD CLINICAL SCIENCE

AWARD

2011 MAYFIELD BASIC SCIENCE

AWARD



CURRENT AND PAST OFFICERS 1980–201110

Current Officers2010 – 2011ChairpersonZiya L. GokaslanChairperson ElectChristopher E. WolflaSecretaryMichael W. GroffTreasurerR. John HurlbertImmediate Past ChairpersonChristopher I. ShaffreyMembers–at–LargeCharles Kuntz, IVMark R. McLaughlinEric L. Zager

Past Officers2009 – 2010ChairpersonChristopher I. ShaffreyChairperson ElectZiya L. GokaslanSecretaryMichael W. GroffTreasurerR. John HurlbertImmediate Past ChairpersonDaniel K. ResnickMembers–at–LargeMark R. McLaughlinChristopher E. WolflaEric L. Zager

2008 – 2009ChairpersonDaniel K. ResnickChairperson ElectChristopher I. ShaffreySecretaryMichael W. GroffTreasurerChristopher E. WolflaImmediate Past ChairpersonJoseph T. AlexanderMembers–at–LargeGregory R. TrostMark R. McLaughlinEric L. Zager

2007 – 2008ChairpersonJoseph T. AlexanderChairperson ElectDaniel K. ResnickSecretaryDaniel K. ResnickTreasurerChristopher E. WolflaImmediate Past ChairpersonCharles L. Branch, Jr.Members–at–LargeKevin T. FoleyGregory R. TrostChristopher I. Shaffrey

2006 – 2007ChairpersonCharles L. Branch, Jr.Chairperson ElectJoseph T. AlexanderSecretaryDaniel K. ResnickTreasurerChristopher E. WolflaImmediate Past ChairpersonRobert F. HearyMembers–at–LargeKevin T. FoleyDaniel H. KimGregory R. Trost

2005 – 2006ChairpersonRobert F. HearyChairperson ElectCharles L. Branch, Jr.SecretaryDaniel K. ResnickTreasurerTimothy C. RykenImmediate Past ChairpersonGerald E. Rodts, Jr.Members–at–LargeJoseph T. AlexanderDaniel H. Kim

2004 – 2005ChairpersonGerald E. Rodts, Jr.Chairperson ElectRobert F. HearySecretaryCharles L. Branch, Jr.TreasurerTimothy C. RykenImmediate Past ChairpersonRegis W. Haid, Jr.Members–at–LargeJoseph T. AlexanderRonald I. ApfelbaumDaniel H. Kim

2003 – 2004ChairpersonRegis W. Haid, Jr.Chairperson ElectGerald E. Rodts, Jr.SecretaryCharles L. Branch, Jr.TreasurerTimothy C. RykenImmediate Past ChairpersonNevan G. BaldwinMembers–at–LargeJoseph T. AlexanderRonald I. ApfelbaumRobert F. Heary

2002 – 2003ChairpersonNevan G. BaldwinChairperson ElectRegis W. Haid, Jr.SecretaryCharles L. Branch, Jr.TreasurerGerald E. Rodts, Jr.Immediate Past ChairpersonPaul C. McCormickMembers–at–LargeRonald I. ApfelbaumH. Louis Harkey, IIIRobert F. Heary

2001 – 2002ChairpersonPaul C. McCormickChairperson ElectNevan G. BaldwinTreasurerGerald E. Rodts, Jr.Immediate Past ChairpersonCurtis A. DickmanMembers–at–LargeRonald I. ApfelbaumH. Louis Harkey, IIIRobert F. Heary

2000 – 2001ChairpersonCurtis A. DickmanChairperson ElectPaul C. McCormickSecretaryNevan G. BaldwinTreasurerGerald E. Rodts, Jr.Immediate Past ChairpersonVincent C. TraynelisMembers–at–LargeH. Louis Harkey, IIISrinath SamudralaLloyd Zucker

1999 – 2000ChairpersonVincent C. TraynelisChairperson ElectCurtis A. DickmanSecretaryNevan G. BaldwinTreasurerCurtis A. DickmanImmediate Past ChairpersonStephen M. PapadopoulosMembers–at–LargeCharles L. Branch, Jr.Srinath SamudralaLloyd Zucker

1998 – 1999ChairpersonStephen M. PapadopoulosChairperson ElectVincent C. TraynelisSecretaryVincent C. TraynelisTreasurerCurtis A. DickmanImmediate Past ChairpersonRichard G. FesslerMembers–at–LargeCharles L. Branch, Jr.Mark N. HadleyJohn E. McGillicuddy

1997 – 1998ChairpersonRichard G. FesslerChairperson ElectStephen M. PapadopoulosSecretaryVincent C. TraynelisTreasurerCurtis A. DickmanImmediate Past ChairpersonEdward C. BenzelMembers–at–LargeCharles L. Branch, Jr.Mark N. HadleyJohn E. McGillicuddy



CURRENT AND PAST OFFICERS 1980–2011 11

1996 – 1997ChairpersonEdward C. BenzelChairperson ElectRichard G. FesslerSecretaryStephen M. PapadopoulosTreasurerPeter M. KlaraImmediate Past ChairpersonArnold H. MenezesMembers–at–LargeGary L. ReaNancy EpsteinJohn E. McGillicuddyEx–Officio MembersKevin T. FoleyMark N. Hadley

1995 – 1996ChairpersonArnold H. MenezesChairperson ElectEdward C. BenzelSecretaryStephen M. PapadopoulosTreasurerPeter M. KlaraImmediate Past ChairpersonRussell L. TravisMembers–at–LargeNancy EpsteinJohn E. McGillicuddyGary L. ReaEx–Officio MembersKevin T. FoleyMark N. Hadley

1994 – 1995ChairpersonRussell L. TravisChairperson ElectArnold H. MenezesSecretaryStephen M. PapadopoulosTreasurerPeter M. KlaraImmediate Past ChairpersonEdward C. TarlovMembers–at–LargeEdward C. BenzelNancy EpsteinGary L. Rea

1993 – 1994ChairpersonEdward C. TarlovChairperson ElectRussell L. TravisSecretaryArnold H. MenezesTreasurerRussell L. TravisImmediate Past ChairpersonVolker K.H. SonntagMembers–at–LargeEdward C. BenzelGary L. Rea

1992 – 1993ChairpersonVolker K.H. SonntagChairperson ElectEdward C. TarlovSecretaryArnold H. MenezesTreasurerRussell L. TravisMembers–at–LargeDonald J. ProloMelville P. Roberts

1991 – 1992ChairpersonCarole A. MillerChairperson ElectVolker K. H. SonntagSecretaryArnold H. MenezesTreasurerRussell L. TravisMembers–at–LargeDonald J. ProloMelville P. Roberts

1990 – 1991ChairpersonEdward S. ConnollyChairperson ElectCarole A. MillerSecretaryVolker K.H. SonntagTreasurerRussell L. TravisMembers–at–LargeArnold H. MenezesDonald J. Prolo

1989 – 1990ChairpersonEdward S. ConnollyChairperson ElectCarole A. MillerSecretaryVolker K.H. SonntagTreasurerRussell L. TravisMembers–at–LargeArnold H. MenezesDonald J. Prolo

1988 – 1989ChairpersonStewart B. DunskerSecretaryCarole A. MillerTreasurerEdward C. TarlovMembers–at–LargePhanor L. Perot, Jr.Volker K.H. Sonntag

1987 – 1988ChairpersonStewart B. DunskerSecretaryCarole A. MillerTreasurerEdward C. TarlovMembers–at–LargePhanor L. Perot, Jr.Volker K.H. Sonntag

1986 – 1987ChairpersonGeorge W. SypertSecretaryHenry H. SchmidekTreasurerEdward S. ConnollyMember–at–LargeCarole A. Miller

1985 – 1986ChairpersonRussell W. HardySecretaryHenry H. SchmidekTreasurerEdward S. ConnollyMember–at–LargeGeorge W. Sypert

1984 – 1985ChairpersonRussell W. Hardy, Jr.SecretaryStewart B. DunskerTreasurerEdward S. ConnollyMember–at–LargeHenry H. Schmidek

1983 – 1984ChairpersonSanford J. LarsonSecretaryStewart B. DunskerTreasurerEdward S. ConnollyMember–at–LargeHenry H. Schmidek



1980 – 1981ChairpersonSanford J. LarsonSecretaryStewart B. DunskerTreasurerEdward S. ConnollyMember–at–LargePhilip R. Weinstein



PAST PROGRAM COMMITTEES 1984–201012

2009 – 2010Peter D. AngevineDean ChouDomagoj CoricSanjay S. DhallW. Jeffrey EliasDaryl R. FourneyJames S. HarropLangston T. HollyAdam S. KanterFrank LaMarcaPraveen V. MummaneniDavid O. OkonkwoShaun T. O’LearyCharles A. SansurDaniel M. SciubbaNirav K. ShahJustin S. SmithMichael P. SteinmetzEve C. TsaiMichael Y. WangLynda J-S. Yang

2008 – 2009James P. BurkeJoseph S. ChengIra M. GoldsteinRobert F. Heary Langston T. HollyR. John Hurlbert Ryan Philip JewellCharles Kuntz, IVPaul G. MatzEhud Mendel Eric A. Potts Richard P. Schlenk Daniel M. SciubbaAllen H. ManikerMarjorie C. Wang Michael Y. WangEric L. Zager

2007 – 2008Joseph S. ChengTanvir ChoudriPeter C. GersztenMichael W. GroffZoher GhogawalaRegis W. Haid, Jr.Robert F. HearyR. John HurlbertRobert E. IsaacsMichael G. KaiserLarry T. KhooDaniel H. KimJohn J. KnightlyCharles Kuntz, IVP. Colby MaherAllen H. ManikerPaul G. MatzMark R. McLaughlinEhud MendelRajiv MidhaChad J. MorganPraveen V. MummaneniStephen L. OndraDaniel K. ResnickTimothy C. RykenChristopher I. ShaffreyMichael P. SteinmetzBrian R. SubachGregory R. TrostMichael Y. WangChristopher E. WolfaEric L. Zager

2006 – 2007Sean D. ChristieMichael W. GroffJames S. HarropR. John HurlbertRobert E. IsaacsJohn J. KnightlyCharles Kuntz, IVAllan D. LeviMark R. McLaughlinEhud MendelDaniel K. ResnickLali H.S. SekhonChristopher I. ShaffreyMichael Y. WangChristopher E. WolflaEric L. Zager

2005 – 2006Joseph T. AlexanderJuan C. BartolomeiJay Y. ChunPeter C. GersztenIra M. GoldsteinMichael W. GroffRegis W. Haid, Jr.James S. HarropRobert F. HearyR. John HurlbertMichael G. KaiserJohn J. KnightlyMark R. McLaughlinEhud MendelPraveen V. MummaneniFred NobanDaniel K. ResnickTimothy C. RykenChristopher I. ShaffreyNirav K. ShahBrian R. SubachSagun K. TuliPaul H. YoungEric L. Zager

2004 – 2005Joseph T. AlexanderJuan C. BartolomeiSteven CashaJoseph S. ChengAndrew T. DaileyAnthony K. Frempong–BoaduMichael W. GroffJames D. GuestBernard H. GuiotRegis W. Haid, Jr.James S. HarropRobert F. HearyR. John HurlbertRobert E. IsaacsMichael G. KaiserCharles Kuntz, IVMark R. McLaughlinEhud MendelRajiv MidhaJunichi MizunoPraveen V. MummaneniNaresh P. PatelEric A. PottsDaniel K. ResnickGerald E. Rodts, Jr.Gregory R. TrostChristopher I. ShaffreyRobert J. SpinnerEric L. Zager

2003 – 2004Joseph T. AlexanderPaul M. ArnoldAndrew T. DaileyMichael W. GroffRegis W. Haid, Jr.Robert F. HearyMichael G. KaiserCharles Kuntz, IVRajiv MidhaDaniel K. ResnickChristopher I. ShaffreyGregory R. TrostGregory C. Wiggins

2002 – 2003Joseph T. AlexanderEdward C. BenzelEugene A. BonarotiAndrew T. DaileyMichael G. FehlingsMichael W. GroffRegis W. Haid, Jr.Robert F. HearyJamie M. HendersonMichael G. KaiserDaniel H. KimRajiv MidhaPraveen V. MummaneniChristopher G. ParamoreGregory J. PrzybylskiDaniel K. ResnickChristopher I. Shaffrey

2001 – 2002Joseph T. AlexanderMichael W. GroffMichael W. GropperRegis W. Haid, Jr.Robert F. HearyMichael G. KaiserCharles Kuntz, IVRajiv MidhaChristopher G. ParamoreGregory J. PrzybylskiDaniel K. ResnickGerald E. Rodts, Jr.Timothy C. RykenBrian R. Subach



PAST PROGRAM COMMITTEES 1984–2010 13

2000 – 2001Joseph T. AlexanderBarry D. BirchMichael G. FehlingsRichard G. FesslerRegis W. Haid, JrH. Louis Harkey, IIIRobert F. HearyR. John HurlbertRajiv MidhaStephen L. OndraChristopher G. ParamoreDaniel K. ResnickGerald E. Rodts, Jr.Timothy C. RykenKenneth S. Yonemura

1999 – 2000Joseph T. AlexanderPaul M. ArnoldNevan G. BaldwinPerry A. BallChristopher H. ComeyBrian G. CuddyMichael G. FehlingsAllan H. FriedmanMitchell R. GropperRegis W. Haid, Jr.Andrea L. HallidayH. Louis Harkey, IIIRobert F. HearyR. John HurlbertJohn J. KnightlyCarl LauryssenAllan D. LeviChristopher G. ParamoreGerald E. Rodts, Jr.William S. RosenbergTimothy C. RykenRobert L. TielVincent C. TraynelisChristopher E. WolflaEric J. WoodardSeth M. Zeidman

1998 – 1999Joseph T. AlexanderNevan G. BaldwinAllan J. BelzbergCharles L. Branch, Jr.Brian G. CuddyRichard G. FesslerMichael G. FehlingsKevin T. FoleyRegis W. Haid, Jr.Andrea L. HallidayH. Louis Harkey, IIINoel I. PerinStephen M. PapadopoulosGerald E. Rodts, Jr.Robert L. Tiel

1997 – 1998Nevan G. BaldwinCharles L. Branch, Jr.Brian G. CuddyRichard G. FesslerH. Louis Harkey, IIIGerald E. Rodts, Jr.

1996 – 1997Ronald I. ApfelbaumPaul M. ArnoldNevan G. BaldwinPerry A. BallAllan J. BelzbergBrian G. CuddyCurtis A. DickmanKevin T. FoleyH. Louis Harkey, IIIJames P. HollowellDavid G. KlinePaul C. McCormickChristopher G. ParamoreNoel I. PerinCharles B. Stillerman

1995 – 1996Nevan G. BaldwinBrian G. CuddyKevin T. FoleyAllan H. FriedmanRegis W. Haid, Jr.H. Louis Harkey, IIIPatrick W. HitchonJames P. HollowellRichard K. OsenbachAllan H. FriedmanNoel I. PerinRobert B. SnowRichard H. TippetsDennis G. Vollmer

1994 – 1995Charles L. Branch, Jr.David W. CahillPaul R. CooperCurtis A. DickmanMichael G. FehlingsRegis W. Haid, Jr.H. Louis Harkey, IIIJames P. HollowellPeter M. KlaraJohn J. KnightlyJohn E. McGillicuddyEugene Rossitch, Jr.Charles B. StillermanVincent C. Traynelis

1993 – 1994David W. CahillCurtis A. DickmanRichard G. FesslerPeter G. GianarisH. Louis Harkey, IIIPaul C. McCormickRuss P. NockelsMoris SenegorVincent C. Traynelis

1992 – 1993Charles L. Branch, Jr.David W. CahillCurtis A. DickmanRichard G. FesslerRegis W. Haid, Jr.Robert J. MartinJohn E. McGillicuddyStephen M. PapadopoulosNoel I. PerinGary L. ReaMoris Senegor

1991 – 1992Bennett BlumenkopfCharles L. Branch, Jr.David W. CahillRichard G. FesslerStephen M. PapadopoulosGary L. Rea

1990 – 1991Joy AprinBenjamin G. BennerLawrence F. BorgesNancy EpsteinEmily D. Friedman

1989 – 1990Bennett BlumenkopfPaul D. DernbachNancy EpsteinEdward C. Tarlov

1988 – 1989John C. GodershyPatrick W. HitchonArnold H. MenezesCarole E. MillerRussell L. Travis

1987 – 1988Melville P. RobertsRichard SaundersVolker K.H. SonntagRussell L. TravisHarold A. Wilkinson

1986 – 1987Joel N. AbromovitzTimothy HarringtonRobert S. HoodVolker K.H. Sonntag

1985 – 1986Stanley J. GoodmanBarth A. GreenJohn F. HoweHector E. JamesRandall W. SmithVolker K.H. SonntagPhilip R. Weinstein

1984 – 1985Barth A. GreenGeorge W. Sypert



CME CREDIT & GENERAL INFORMATION14

CME CREDITThis activity has been planned andimplemented in accordance with theEssentials and Standards of theAccreditation Council for ContinuingMedical Education through the jointsponsorship of the Congress ofNeurological Surgeons and theAANS/CNS Section on Disorders of theSpine and Peripheral Nerves. TheAccreditation Council for ContinuingMedical Education (ACCME) accreditsthe CNS to sponsor continuing medicaleducation for physicians.

US Physicians: The CNS designates thislive activity for a maximum of 27 AMAPRA Category 1 Credits™. Physiciansshould only claim credit commensuratewith the extent of their participation inthe activity.

The same number of category 1 creditsawarded will be applied toward theContinuing Education Award inNeurosurgery.

*A maximum of 19 AMA PRA Category 1Credits™ may be earned for ScientificSessions only.

Physician Assistant/PhysicianExtender/and Other Allied HealthProfessionals: Attendees will receivecredits for attendance at the generalscientific program and for any optionalevents attended. Each physicianassistant/physician extender/alliedhealth professional should contact his orher individual membership associationand certification board to determine therequirements for accepting credits. Allattendees will receive a certificate ofattendance.

Additional CME Credits can be earned byattending the following:

Special CoursesAttendees will receive a maximum offour (4) AMA PRA Category 1 Credits™for each eligible half-day SpecialCourse. Physicians should only claimcredit commensurate with the extentof their participation in the activity.

Luncheon SymposiaAttendees will receive a maximum of two(2) AMA PRA Category 1 Credits™ foreach eligible Luncheon Symposium.Physicians should only claim creditcommensurate with the extent of theirparticipation in the activity.

PostersPhysicians may claim AMA PRA Category1 Credit™ directly from the AMA forpreparing a poster presentation, whichalso includes the published abstracts.Physicians may claim them on their AMAPRA certificate application or applydirectly to the AMA for an AMA PRACategory 1 Credit™ certificate. Physiciansmay claim AMA PRA Category 2 Credit™for viewing scientific posters. Physiciansshould self-claim credit on their AMAPRA certificate application form.

Speaker Ready RoomThe Speaker Ready Room, located inPinnacle Peak 3, will be available:

Wednesday, March 9 8:00 AM - 6:00 PMThursday, March 10 6:00 AM - 6:00 PMFriday, March 11 6:00 AM - 5:00 PMSaturday, March 12 6:00 AM - 12:30 PM

All speakers and abstract presentersshould visit the Speaker Ready Roomprior to their presentation. All ScientificSession Faculty are required to check in atthe Speaker Ready Room 24 hours aheadof your presentation.

Exhibit Hall Hours: The Exhibit Hall is located in the GrandCanyon Ballroom.Thursday: 9:00 AM - 7:00 PMFriday: 9:00 AM - 12:00 PMSaturday: 9:00 AM - 12:00 PM

Registration Hours: Registration is located in the GrandCanyon Foyer.Wednesday: 8:00 AM - 6:00 PM Thursday: 6:00 AM - 6:00 PMFriday: 6:00 AM - 5:00 PMSaturday: 6:00 AM - 12:30 PM

No Smoking PolicySmoking is not permitted at any officialAANS/CNS Section on Disorders of theSpine and Peripheral Nerves AnnualMeeting event. The JW Marriott DesertRidge is a non-smoking hotel.

DisclaimerThe material presented at the 2011Annual Meeting has been made availableby the AANS/CNS Section on Disorders ofthe Spine and Peripheral Nerves and theCNS for educational purposes only. Thesematerials are not intended to representthe only, nor necessarily the best methodor procedure appropriate for the medicalsituations discussed, but rather are

intended to present an approach, view,statement or opinion of the faculty, whichmay be helpful to others who face similarsituations.

All drugs and medical devices used in theUnited States are administered inaccordance with the Food and DrugAdministration (FDA) regulations. Theseregulations vary depending on the risksassociated with the drug or medicaldevices compared to products already onthe market, and the scope of the clinicaldata available.

Some drugs and medical devicesdemonstrated or described within theprint publications of the AANS/CNSSection of Disorders of the Spine andPeripheral Nerves jointly sponsored bythe CNS have FDA clearance for use forspecific purposes or for use only inrestricted research settings. The FDA hasstated that it is the responsibility of thephysician to determine the FDA status ofeach drug or device he or she wants touse in compliance with applicable laws.

Neither the content (written or oral) ofany course, seminar or other presentationin the program, nor the use of a specificproduct in conjunction therewith, nor theexhibition of any materials by any partiescoincident with the program, should beconstrued as indicating endorsement orapproval of the views presented, theproducts used or the materials exhibitedby the AANS/CNS Section on Disorders ofthe Spine and Peripheral Nerves jointlysponsored by the CNS, or by itscommittees, commissions or affiliates.

The following companies haveprovided an educational grantin support of the 2011 Annual

Meeting Special Courses.

Medtronic

Biomet Spine

NuVasive



DISCLOSURES 15

Khalid M. AbbedConsulting Agreement:Medtronic

Chris AirriessSalary:California Stem Cell

Joseph T. AlexanderConsulting Agreement: Stryker Spine

Christopher P. AmesHonoraria:DePuy; Medtronic; Stryker

Paul A. AndersonConsulting Agreement:MedtronicOwnership Interest: Spinemedica;Expanding Orthopedics; Pioneer; TitanSurgicalRoyalty: Stryker

Paul M. ArnoldConsulting Agreement:K2M; Integra:Medtronic; Stryker Spine

Henry E. AryanConsulting Agreement: Stryker

Wilson T. AsforaOwnership Interest:Medical Designs, LLC

Hyun BaeRoyalty:NuVasive, Inc.

Jonathan B. BellotteConsulting Agreement: Alphatec Spine;MedtronicOwnership Interest: Applied SpineTechnologies

Christopher BonoConsulting Agreement:Harvard ClinicalResearch InstituteRoyalty:Wolters Kluwer; Informa HealthCare

Duccio BoscheriniConsulting Agreement:Medtronic

Charles L. BranchConsulting Agreement:MedtronicOther Financial or Material Support:NASSRoyalty:Medtronic

Ali BydonOther Financial or Material Support:DePuy Spine

Jens ChapmanOther Financial or Material Support: HJWyss Foundation; Stryker; AlseresPharmaceuticals; AOSNA; Medtronic

Boyle C. ChengConsulting Agreement: Alphatec Spine;MedtronicOwnership Interest: Applied Science

Joseph S. ChengHonoraria: Synthes

Randall Matthew ChesnutConsulting Agreement: Synthes; IntegraLife Sciences

John ChiConsulting Agreement: Stryker Spine

Dean ChouHonoraria: Stryker Spine

Domagoj CoricConsulting Agreement: Pioneer Surgical;DePuy Spine; Spine Wave; Spinal Motion

Mark B. DekutoskiConsulting Agreement:Mayo MedicalVentures/MedtronicHonoraria: AO FoundationOther Financial or Material Support:Medtronic; DePuy; Stryker; Synthes;Broadwater Associates CME Group

Sebastian DendorferSalary: AnyBody Technology

Harel DeutschConsulting Agreement: StrykerHonoraria:DePuy

Curtis A. DickmanRoyalty:Theime Medical Publishing

Randall DryerOwnership Interest: Facet SolutionsRoyalty:Medtronic; NuVasive

Neil DuggalConsulting Agreement: Synergy DiscReplacement, Inc.Honoraria:Medtronic BiologicsOther Financial or Material Support:Synthes Spine

E. Hunter DyerOwnership Interest: Pioneer Surgical

Michael G. FehlingsConsulting Agreement:DePuy SpineRoyalty:DePuy Spine

Richard G. FesslerConsulting Agreement:MedtronicRoyalty:DePuy; Medtronic; Stryker

Kevin T. FoleyConsulting Agreement: ArthroCare;Medtronic; NuVasiveIntellectual Fees: ArthroCareOwnership Interest:TrueVisionRoyalty:Medtronic

Anthony Frempong-BoaduHonoraria:Medtronic

Fred H. GeislerConsulting Agreement: Zimmer;Medtronic; NuVasive; Spinal Motion;Vertiflex; AesculapStockholder: Impliant; Disc Motion

Edward J. GerberOwnership Interest:NuVasive

Ziya L. GokaslanOther Financial or Material Support:NREF; Integra; DePuy; Medtronic; AONorth AmericaOwnership Interest: Spinal Kinetics; U.S.Spine

J. Allan GoodrichConsulting Agreement:NuVasive

Arnold Graham-SmithConsulting Agreement: SI-Bone, Inc.

Michael W. GroffConsulting Agreement: EBI Spine BiometRoyalty:DePuy Spine

The AANS/CNS Section on Disorders of the Spine and Peripheral Nerves and the CNS control the content and production of thisCME activity and attempt to assure the presentation of balanced, objective information. In accordance with the Standards forCommercial Support established by the Accreditation Council for Continuing Medical Education, anyone in the position tocontrol the content of the educational activity is asked to disclose any relationship they have with commercial companies.Individuals who have disclosed a relationship* with commercial companies whose products may have a relevance to theirparticipation in the Annual Meeting are listed here.

*Relationship refers to receipt of royalties, consultantship, funding by research grant, receiving honoraria for educational serviceselsewhere, or any other relationship to a commercial company that provides sufficient reason for disclosure.



DISCLOSURES16

Richard D. GuyerConsulting Agreement: Spinal Motion

Regis W. HaidConsulting Agreement:Globus Medical;Piedmont Health CareOther Financial or Material Support:Globus Medical; Medtronic; NuVasiveOwnership Interest: Spine UniverseRoyalty:Medtronic

John Jay HalkiConsulting Agreement: SI-Bone, Inc.

Arik HanannelSalary: InSightec

J. Frederick HarringtonConsulting Agreement: Zimmer Spine

James S. HarropConsulting Agreement:DePuy Spine;Ethicon; Neural StemOther Financial or Material Support:Geron; Ascubio; Axiomed

David J. HartConsulting Agreement: Aesculap Spine;Integra; Depuy Spine; TranS1

Charles A. HartjenConsulting Agreement: Facet Solutions;MedtronicIntellectual Fees: Facet SolutionsOwnership Interest:K2M

Roger HartlOther Financial or Material Support:Apatech; Spine Wave; Brainlab; Synthes

Robert F. HearyOther Financial or Material Support:DePuy Spine; Biomet SpineRoyalty:Depuy Spine; Thieme MedicalPublishers; Zimmer Spine

John G. HellerConsulting Agreement:Medtronic

Jason M. HighsmithConsulting Agreement: Boston Scientific

Patrick W. HitchonOther Financial or Material Support:DePuy Spine

Langston T. HollyConsulting Agreement:Medtronic

John K. HoutenHonoraria:MedtronicOther Financial or Material Support:Stryker Spine

Patrick C. HsiehConsulting Agreement:Medtronic; DePuySpine

Jonathan HydeConsulting Agreement:NuVasive

Cary IdlerConsulting Agreement:NuVasive

Robert E. IsaacsConsulting Agreement:NuVasive

R. Patrick JacobConsulting Agreement: Synthes Spine

George I. JalloConsulting Agreement:Codman;Medtronic

Michael JanssenOther Financial or Material Support:AOSNA

J. Patrick JohnsonConsulting Agreement: Alphatec; PioneerMedical; SpineWave; Johnson & Johnson;Biomet; DePuy; FlexUspineStockholder: Alphatec; Pioneer Medical;FlexUspine; SpineWave

Terrence D. JulienConsulting Agreement:Orthovita; GlobusMedical; Trinity Orthopedics; StrykerSpineHonoraria:MedtronicStockholder:Orthovita

Iain H. KalfasRoyalty:Mako

Adam S. KanterConsulting Agreement: Lanx, NuVasive

Dean KarahaliosConsulting Agreement: Anulax, Lanx,MedtronicOwnership Interest: LanxRoyalty:Medtronic; Anulax; Lanx

Hans S. KeirsteadOwnership Interest:California Stem Cell

Larry T. KhooConsulting Agreement:DePuy Spine;Globus Medical; TranS1; Zimmer Spine

Kee Duk KimConsulting Agreement:Covidien

Branko KopjarConsulting Agreement:Vertiflex;SpineMark; Scient’X; Lanx, Inc.; Johnson& Johnson; Cerepedics, Inc.

Tyler R. KoskiConsulting Agreement:MedtronicHonoraria:DePuy; Stryker

Ryan M. KretzerConsulting Agreement:Chestnut Medical;eV3

Charles Kuntz, IVConsulting Agreement: SynthesGrants: Synthes; Stryker; AOSpineOwnership Interest:Mayfield Clinic;Precision Radiotherapy; Priority Consult;CKIV Alignment; The Christ HospitalSpine Surgery CenterOther Financial or Material Support:AOSpine; Synthes; Stryker

Frank La MarcaConsulting Agreement: Biomet; Globus;DePuy; Medtronic

Lawrence LenkeOther Financial or Material Support:DePuy SpineRoyalty:Quality Medical Publishing;Medtronic

Kyle MaloneSalary:NuVasive

Mark R. McLaughlinConsulting Agreement: Spine Wave; Ownership Interest: Spine Wave

Ehud MendelHonoraria: Stryker Spine; Baxter; Synthes

Rajiv MidhaOther Financial or Material Support:CIHR

Charles Joseph MillerConsulting Agreement:Medical Designs,LLC

Praveen V. MummaneniConsulting Agreement:DePuy Spine;MedtronicOwnership Interest: 2N LLC

Rania NasisSalary:California Stem Cell

Ewell Lee NelsonConsulting Agreement:Medtronic

Pierce D. NunleyConsulting Agreement: Spinal Motion

David O. OkonkwoConsulting Agreement: Lanx; SynthesHonoraria:Medtronic



DISCLOSURES 17

Brian A. O’ShaughnessyConsulting Agreement:DePuy

Paul ParkConsulting Agreement:DePuy SpineGrants:Orthofix

Naresh P. PatelConsulting Agreement:Orthofix;Medtronic; Stryker Spine

Mick J. Perez-CruetConsulting Agreement: Aesculap; Stryker;Zimmer SpineOwnership Interest:Thompson MIS; MI4Spine

Kenneth PettineRoyalty:Medtronic

Frank M. PhillipsConsulting Agreement:NuVasive, Inc.Royalty:NuVasive, Inc.

Eric A. PottsConsulting Agreement: Lanx; MedtronicOwnership Interest: LanxRoyalty:Medtronic

Srinivas K. PrasadHonoraria: Stryker Spine

Christopher D. PritchardBoard Trustee or Officer Position: InVivoTherapeutics

Alfredo Quinones-HinojosaOther Financial or Material Support:Leica; Stryker; Porex; Eisai; Vycor

Kevin A. RahnConsulting Agreement:NuVasiveOwnership Interest:Titan Spine

John RasmussenSalary: AnyBody Technology

W. Carlton RecklingConsulting Agreement: SI-Bone, Inc.

John J. ReganConsulting Agreement: Facet SolutionsIntellectual Fees: Integra Life SciencesOwnership Interest: Pioneer Surgical

Mark ReileyOwnership Interest: SI-Bone, Inc.Stockholder: SI-Bone, Inc.

Francis M. ReynoldsOwnership Interest: InVivo Therapeutics

Laurence D. RhinesHonoraria:Medtronic; Biomet

Lee H. RileyOther Financial or Material Support:Lifenet Health; CSRS

Bruce RobieOwnership Interest: ARO Medical, LLC

Jody A. RodgersOwnership Interest:NuVasive

W.B. RodgersConsulting Agreement:TranS1; NuVasive;ExactechOwnership Interest:NuVasiveRoyalty:NuVasive

Gerald E. Rodts, Jr.Consulting Agreement:Globus Medical,Inc.; Orthofix, Inc.Other Financial or Material Support:SpineUniverse.comRoyalty:Globus Medical, Inc.

Leonard M. RudolfOwnership Interest: SI-Bone, Inc.

Timothy C. RykenConsulting Agreement:Medtronic Inc;Merck Inc / Schering-Plough Inc; Eisai

Amer F. SamdaniConsulting Agreement:DePuy Spine;SpineVision; Synthes Spine

Rick SassoOther Financial or Material Support:CerapedicsRoyalty:Medtronic

Christopher I. ShaffreyConsulting Agreement: Biomet Spine;DePuy; MedtronicGrants: AO; Department of Defense;National Institutes of Health; NACTNOther Financial or Material Support:Medtronic

Mark Edwin ShaffreyOther Financial or Material Support:DePuy Spine

A. Nick ShamieConsulting Agreement: SI-Bone, Inc.

Ashwini Dayal SharanConsulting Agreement:NLT; St. Jude;MedtronicHonoraria: IntegraOwnership Interest: ICVRX; IntellectRoyalty: Zimmer

Lilach ShaySalary: Shira Nehemia Bio-MedicalEngineering

Jonathan D. ShermanConsulting Agreement:DePuy; Medtronic

Jonathan R. SlotkinConsulting Agreement: Stryker Spine;InVivo Therapeutics, Inc.Honoraria: Synthes Spine

Justin S. SmithConsulting Agreement: Axial Biotech;Biomet; MedtronicHonoraria: Biomet; DePuyOther Financial or Material Support:DePuy; Medtronic

Solas Degenerative Study GroupConsulting Agreement: NuVasiveOther Financial or Material Support:NuVasive

Matthew SongerOwnership Interest: Pioneer Surgical

Volker K. H. SonntagRoyalty:Medtronic

Leo R. SpectorIntellectual Fees: Synthes

John G. StarkConsulting Agreement: Signus MedicalOwnership Interest: Ilion Medical

Michael P. SteinmetzConsulting Agreement: Biomet Spine

William R. TaylorIntellectual Fees:NuVasive

John M. TewConsulting Agreement:KLS Martin;Cosman Medical

Antoine TohmehConsulting Agreement:NuVasive

Soren TorholmSalary: AnyBody Technology

Jeffrey M. TothConsulting Agreement:MedtronicOther Financial or Material Support:Lanx, Inc.; Osteotech, Inc.; Medtronic

Vincent C. TraynelisConsulting Agreement:UnitedHealthCare; MedtronicRoyalty:Medtronic

Gregory R. TrostHonoraria:Medtronic



DISCLOSURES18

Eve C. TsaiOther Financial or Material Support:Brainlab; Stryker Spine; Synthes

Joseph TurnerConsulting Agreement:Medtronic

Jamie Sue UllmanConsulting Agreement:OxygenBiotherapeuticsHonoraria: Brain Trauma Foundation

Juan S. UribeConsulting Agreement:NuVasive;Medtronic; Orthofix

Antonio ValdevitConsulting Agreement:Medtronic

Brent VanconiaSalary: St. Mary’s Health Center

Melvin WahlConsulting Agreement:NuVasive

Jeffrey WangRoyalty: Zimmer; Seaspine; Biomet;Stryker; Osprey; Aesculap; Amedica;Medtronic; Alphatech

Marjorie C. WangSalary: Robert Wood Johnson PhysicianFaculty Scholars Program

Michael Y. WangConsulting Agreement: Aesculap Spine;Biomet; DePuy SpineOwnership Interest:NeuroConsulting,LLC; NeuroConsulting Specialists, LLC

William Charles WelchBoard Trustee or Officer Position:Pittsburgh Standard SpineConsulting Agreement: Zimmer SpineGrants: Synthes SpineOther Financial or Material Support:Lanx, Inc.

Bryan J. WellmanConsulting Agreement:Medical Designs,LLC

Donald M. WhitingConsulting Agreement:Medtronic;Alphatec SpineOwnership Interest: Applied ScienceTechnologies

Beth A. WinkelsteinOther Financial or Material Support:Synthes

Eric J. WoodardOwnership Interest: InVivo TherapeuticsCorporationRoyalty: Stryker SpineHonoraria:DePuy Spine

Lynda Jun-San YangOther Financial or Material Support:Sparton Corp.

Sangwook YoonOther Financial or Material Support:Biomet; Phygen; OMEGA; AOSNA; OREFRoyalty: Stryker; Nexgen

Jim A. YoussefConsulting Agreement: Aesculap/B.Braun; DePuy; NuVasive; SeaSpineOther Financial or Material Support:DePuy; Stryker; NuVasive; StrykerBiotech; BioSurface EngineeringTechnologies; Facet Solutions; AdvancedTechnologies in Regenerative Medicine;Axial BiotechOwnership Interest: AmedicaRoyalty:Osprey; Aesculap/B. Braun;DePuy; NuVasive; Seaspine

As of February 11, 2011

Oran AaronsonTuychiboy AbdullaevAmir AbtahiFrank L. AcostaOwoicho AdogwaBasheal M. AgrawalAntonio AguileraHenry AhnGeorge Al ShamyDunbar S. AlcindorRonald AlkalayFahad A. AlkherayfKyle D. AllenAnubhav AminNeel AnandVijay K. AnandAditya AnchaBill AndersonDaniel G. AndersonKaren K. AndersonRichard C. E. AndersonPeter D. AngevineRein AntonColette Ap Rhys

Kristen Archer-SwygertVincent ArletIñaki ArroteguiDimitrios ArvanitakisBasar AtalayOla AwadYunus AydinAli A. BaajJason BabuskaBradley T. BaganCarlos A. BagleyMirza N. BaigRobert J. BancoMarco BarberoMichal BarnaDaniel L. BarrowJack BarrowBenjamin BaskinTracey BastromUlrich BatzdorfJoel A. BaumanNrupen BaxiYasar BayriRobert Bazzano

Andrew BeckerDeniz BelenThomas W. BelknapAllan J. BelzbergRandal BetzKarin S. BierbrauerBarry D. BirchAllen T. BishopErica BissonBennett BlumenkopfMargaret BoltesStefano BorianiOrland K. BoucherHakan BozkusThomas B. BriggsDouglas L. BrockmeyerDarrel S. BrodkeNathaniel P. BrooksJustin M. BrownKelli BuntonJames BurgessClinton Judson BurkettSigita BurneikieneMohamad Bydon

Sedat CagliPatrick CahillBlair CalancieEliezer CaloPhilippe CampeauxHakan H. CanerArturo Cardenas-BlancoCameron CarmodyFrances A. CarrIsrael CaspiHalit ÇavusogluSuleyman CayliWade CeolaKaisorn L. ChaichanaChen-Kuei ChangChristopher ChaputBudong ChenJ. ChenChun-Yu ChengHenrich ChengDaniel R. ChernavvskyBrandon G. ChewWen-Ta ChiuKyoung Suok Cho

NOTHING TO DISCLOSEIndividuals who have reported they do not have any relationship with commercial companies are listed here.



DISCLOSURES 19

Haroon F. ChoudhriTanvir ChoudhriDon ChowFinn ChristensenSusan ChristopherChu-Hsiang ChuMegan ClarkMichelle J. ClarkeBrenton R. CogerAnthony G. ConteDaniel CookDavid M. CookDavid CooleyPaul R. CooperChase CornGarth Rees CosgroveJean-Valery CoumansDaniel Edward CoutureCatharine CravenColin CrosbyBryan W. CunninghamJill CurranBradford CurtDavid Del CurtoErgun DagliogluElias DakwarAli DalgicColin DaltonMargot DamaserDavid J. DanielsMaureen A. DarwalHormuzdiyar H. DasenbrockAileen DavisBrandon J. DavisRaphael P. DavisAntonella De CarloEnrico De MicheliKevin J. DeLuzioStacie DeMentGulden DemirciClint DevinClinton J. DevinSundeep DhaliwalSanjay S. DhallRoberto Jose DiazMarine DididzeThomas DimmigDarryl J. DirisioDenizhan DivanliogluMichael J. DorsiEric J. DozoisDoniel DrazinBrian DrewJack H. DunnBrett C. EbelingPaul K. EdwardsKelly EganKurt M. EichholzGregg ElbertEnayatkhater Omar Elkelany

Eric H. ElowitzLuella EngelhartJack EngsbergSang Soo EunJesse EvenJ. E. EvinAnthony P. FabriziAsdrubal FalavignaIgor FaquiniChad W. FarleyDaniel Robert FassettNathan FaulknerLi-Yu FayJohn F. FergusonJoel FinkelsteinMichael A. FinnCharles FisherPhyllis FlomenbergMatthew FooteMichael FordDaryl R. FourneyJohn FranceColin FranzJuliano FrateziAllan H. FriedmanKai-Ming G. FuErin FulchieroMosfata GabrRobert M. GallerLaura GanauMario GanauSarah T. GarberMark P. GarrettAngelina N. GarvinChristian GeannetteHarry H. GebhardZachariah Maliakal GeorgeJohn W. GermanMassimo GerosaZoher GhogawalaSamer GhostineCaterina GianniniFederico GirardiDave GladowskiWayne GlufShankar Prakash GopinathCharley GordonTessa GordonOded GorenCristian GragnianielloR. Scott GrahamRichard GrayMark GreenbergJoey Kevin GrochmalMarshall L. GrodeJonathan A. GrossbergBenjamin B. GuarinoBarton L. GuthrieSergio GutiérrezRobert J. Hacker

Mark N. HadleyRyan J. HalpinD. Kojo HamiltonShannon HannCarolyn HardinRan HarelSagi HarnofKyle M. HealyMarie-Noelle Hebert-BlouinSamantha HemingwayTheresa HernandezShawn Hervey-JumperGirish K. HiremathRobert A. HirschlJoseph Kyle HobbsChristoph HofstetterDaniel J. HohJeffrey R. HoltzBrian James HoodWesley HsuNianbin HuWen-Cheng HuangPil Woo HuhCraig S. HumphreysR. John HurlbertPriscilla HwangRoy HwangSteven Wei-Hung HwangAllison HyngstromChristopher A. IannottiChris IdemmiliYael InbarLine JacquesWilliam E. JanesNicolas V. JaumardMohammed Ali JazayeriMithulan JegapragasanArthur L. JenkinsDiana JhoHai-Hong JiangIsmael Jimenez-EstradaLiufang JingMichael JirgisMichael JirjisGarth JohnsonLakesha JohnsonClinton JungOkan KahyaogluMichael G. KaiserUdaya K. KakarlaFrank KandzioraTakahisa KanekoTuncay KanerErkan KaptanogluChris S. KarasIsaac KarikariAlina KarpovaManish K. KasliwalBettina KellerElizabeth Kenney

Tyler J. KenningSafdar KhanYevgeniy Anatoliy KhavkinCumhur KilincerInsoo KimJin-Sung KimTerrence T. KimZdenek KlezlJohn J. KnightlyKemal KocRicardo Jorge KomotarDeniz KonyaAndreas KorgeMurat KorkmazThomas KosztowskiKadir KotilIzabela KowalczykIzumi KoyanagiWilliam E. KraussAjit A. KrishnaneyJan KrylAbhaya Vivek KulkarniDavid KungShekar N. KurpadSun KwonJohn J. LabiakFred Chiu-lai LamRobert LangerSophia Lang-PerezDarryl LauIlya LauferBruno C.R. LazaroTien V. LeRichard L. LebowDarko LedicBrendan LeeHo-Yeon LeeJY LeeMing-Hsueh LeeSang Bok LeeSang-Ho LeeTae Gyu LeeMichael LemoleDaniel LeonardJason LernerJim LeskoAllan D. LeviKhai LhamChien-Min LinChun-Hsien LinMao-Tsun LinMartin LinDavid LoebBaron LonnerDavid C. LoPrestiDaniel C. LuJohn LucioNeal LutherMark K. LyonsSamuel J. Mackenzie



DISCLOSURES20

Marcella MaderaRaffaella MainaMitchell Gil MaltenfortJacinto ManonFrances MaoPetra MargeticMichelle MarksRobert A. MarshJonathan MartinJoseph J. MarzluffAlexander MasonEric M. MassicottePaul C. McAfeeEdward McCarthyJamal McClendonPaul C. McCormickKirk McCulloughMatthew McGirtAnkit Indravadan MehtaGregory A. MencioArnold H. MenezesScott A. MeyerJames MillsAgrawal Basheal MohanAhmed MohyeldinBahram MokriCamilo A. MolinaChad J. MorganThomas MrozRyan D. MuchowDebraj MukherjeeTomohiro MurakamiDaniel B. MurreyAhmet Murat MüslümanS. Terence MylesOsman NacarSait NaderiRobert Partlow NaftelRani NasserPetr NesnidalBenjamin NewmanPeter NewtonShahid Mehdi NimjeeKo-Chi NiuEric W. NottmeierMiriam NunoDonna D. OhnmeissOnder OkayTunc OktenogluShaun T. O’LearyStephen L. OndraJoseph O’NeilKevin O’NeillTimothy M. O’SheaLauren Rose OstlingAdetokunbo A. OyeleseCagatay OzdolMemet OzekAli Fahir OzerFahir Ozer

Selcuk Omer PalaogluHung-Chuan PanGuergana PanayotovaChun Kun ParkJon ParkScott L. ParkerScott ParkerRobert S. PashmanAlexandra PaulRamiro Perez de la TorreKaren PetronisDavid B. PettigrewMark A. PichelmannMaurizio PintucciErsin PolatGlen PollockDavid W. PollyRyan PontonRandall W. PorterJoshua E. PreissRoss PufferSharad RajpalEdwin RamosShilpa RaoDaniel M. S. RaperDavis ReamesPablo F. RecinosViolette Renard RecinosRajesh ReddyAlexa Lynne ReevesAdam S. ReigDaniel K. ResnickWilliam J. RichardsonOrlando RighessoEva RitzlDennis Allen RobertsJack P. RockDarren RoffeyPeter RoseMichael K. RosnerAndrew L. RossEnis SabanAbraham E. SaberskyArjun SahgalTatianna Olivia SalehSrinath SamudralaCharles A. SansurRachel Sarabia-EstradaMehdi SasaniDwight SaulleLuigi SchiabelloMichael SchiraldiChristian SchlichtMeic H. SchmidtBrian SchmitWerner SchmolzJoseph SchreiberAlbert Jesse SchuetteJames M. SchusterTheodore H. Schwartz

Daniel M. SciubbaCara SedneyNeda I. Sedora-RomanHoward B. Seim, IIILori A. SettonSagar R. ShahMohammed F. ShamjiAdrija SharmaBrian ShenderPatrick ShihAlexander Y. ShinBenjamin ShinJohn H. ShinRobert ShugartDaniel J. SiegwartIbet Marie SihPedro Guaresi SilvaNathan E. SimmonsOliver P. SimmonsAnoushka SinghBhagat SinghHarshpal SinghTerra SlatonJohn M. SmallIgor SmirnovJason S. SmithTimothy R. SmithWilliam D. SmithWilliam Douglas SmithZachary Adam SmithHeather SpaderRobert J. SpinnerMarin F. StancicRobert M. StarkeJeffrey A. SteinbergBrian D. StemperEdwin Andrew StevensDavid StiddAndrea L. StrayerJan StulikBrian R. SubachPatrick Alexander SugrueIan SukKarin R. SwartzThomas A. SweaseyNikolaos SyrmosPo-An TaiAdesh TandonBobby TayAlisson TelesAmy TheilerNicholas TheodoreJohn A. ThomasJorge TorresP. Justin TortolaniApostolos TsiourisLuis M. TumialanCengiz TuncerOsman Nuri TürkmenogluA. Simon Turner

Michael Scott TurnerOzhan UckunJohn L. UlmerHidemasa UmekojiCheerag UpadhyayaAlexander R. VaccaroFernando L. ValeNico van RooijenShoshanna S. VaynmanMilorad VilendecicAlan T. VillavicencioEugene WaiBeverly C. WaltersAnthony C. WangJeffrey C. WangMei WangBrittany WeeksPhilip R. WeinsteinChristine L. WeisshaarRobert Gray WhitmoreJack E. WilbergerBrian Jeremy WilliamsSeth WilliamsJefferson WilsonTimothy F. WithamChristopher E. WolflaJean-Paul WolinskyCyrus Chi-Ho WongKamal Ronald WoodsJodie B. WoznicaNeill Marshall WrightZachary G. WrightJau-Ching WuQing Gui XuRisheng XuJen-Tsung YangWei-Hsun YangReza YassariDonald Y. YeUlas YenerGayane YenokyanRaymond YerlyAli YildirimNarayan YoganandanDo Sung YooDaryl YoungAlexander Kwong-Tak YuKemal YucesoyKasim Zafer YukselEric L. ZagerMehmet ZileliRichard S. ZimmermanDoug Zochodne




DISCLOSURES 21

Scientific Session I: EvidenceBased Spine Surgery in theReal World Daryl R. Fourney

Scientific Session II: SpinalSurgery ComplicationAvoidance and Management James S. HarropPatrick C. HsiehSrinivas K. Prasad

Scientific Session III:Evolution of Treatment forMetastatic DiseaseDaryl R. Fourney

David Cahill MemorialControversies: Spine andPeripheral Nerves Burst Fracture IntactJames S. HarropCharles Kuntz, IV

Pediatric CraniocervicalSocietyRichard C.E. Anderson

Special Course II: Masters inSpinal Surgery: What HasExperience Taught Me?Regis W. Haid

Special Course III: SpinalDeformityPeter D. AngevineJames S. HarropCharles Kuntz, IVPraveen V. MummaneniJuan S. Uribe

Special Course IV: AdvancedMIS Techniques/ManagingMIS ComplicationsMick J. Perez-Cruet

Special Course V: Managementof Perioperative PainSanjay S. Dhall

Special Course VI: Update onSpinal Surgery in TurkeyBasar AtalaySedat CagliSuleyman CayliKadir KotilFahir Ozer

Special Course VII: CervicalMyelopathy (co-sponsored byCSRS)Lee H. RileyRick Sasso

Special Course IX: Evaluationand Management of the SpineTrauma PatientSanjay S. DhallEve C. Tsai

Luncheon Symposium IV:Geriatric SpineJames S. Harrop

Luncheon Symposium V:Spinal ArthroplastyRegis W. Haid

Case PresentationsDavid J. HartPatrick C. Hsieh

Oral Platform Presentations IIPaul M. ArnoldCharles Kuntz, IV

What’s New Session IIJohn Chi

What’s New Session IIISanjay S. Dhall

Mayfield and OutcomesAwards119: Darryl J. Dirisio

Oral Platform Presentations IAli Bydon104: Roberto Jose DiazOral Platform Presentations II113: Domagoj Coric

Oral Poster Presentations I203: D. Kojo Hamilton204: Domagoj Coric

Oral Poster Presentations IIJohn Chi228: Dwight Saulle229: Jamal McClendon241: Jan Stulik

Digital Posters306: Christoph Hofstetter307: Kenneth Pettine320: Sanjay S. Dhall321: Hung-Chuan Pan349: Fred Chiu-lai Lam354: Ali Bydon355: Ryan M. Kretzer370: Kasim Zafer Yuksel384: Ali Dalgic392: Samer Ghostine393: John G. Stark395: Sharad Rajpal401: Kasim Zafer Yuksel404: Brian James Hood417: Kenneth Pettine427: Bruce Robie438: Iñaki Arrotegui439: Iñaki Arrotegui450: Luis M. Tumialan458: Li-Yu Fay461: Kenneth Pettine


NON-FDA APPROVED LISTINGFaculty Presentations Including Non-FDA Approved Investigational Drugs or Devices



MEETING AGENDA22

WEDNESDAYMARCH 91:30 – 5:30 PM

Desert Conference Suite III

PEDIATRIC CRANIOCERVICAL SOCIETY $200 includes lunchCourse Director: Douglas L. BrockmeyerFaculty: Richard C.E. Anderson, Daniel Edward Couture, Jonathan MartinCourse Description: This course willserve as a symposium for those with aninterest in pediatric craniocervicalabnormalities and disease. It seeks toexamine issues related to management ofpediatric craniocervical disease includingsurgical and non-surgical treatment,complication management, and diseasepathophysiology.Learning Objectives: Upon completion ofthis course, participants should be able to:w Apply appropriate management of

complex pediatric craniospinal disorders.

w Utilize appropriate research strategies to further the care of patients with craniospinal disorders.

w Apply the mechanism involved in the pathophysiology and progression of pediatric craniocervical disease.

1:30 – 3:30 PMRoundtable Discussion and Presentations

3:30 – 3:45 PMBreak

3:45 – 5:30 PMRoundtable Discussion and Presentations

1:30 – 5:30 PMGrand Canyon 9

SPECIAL COURSE ICoding Update and Review$200 includes lunchCourse Directors: Joseph S. Cheng, John J. KnightlyFaculty: Peter D. Angevine, Domagoj Coric, R. Patrick Jacob, Karin R. SwartzCourse Description: This course willprovide up-to-date information oncurrent issues in spine coding. Codingscenarios will be reviewed for the correctcoding of routine as well as complexspinal procedures.

Learning Objectives: Upon completion ofthis course, participants should be able to:w Integrate the newest changes in CPT

coding for spine.w Apply the methodology for correct

spine coding.w Identify specific difficult coding

scenarios and bring clarity to the coding process.

1:30 – 1:45 PMIntroduction and Future Issues for Coding(ICD-10)Joseph S. Cheng, John J. Knightly

1:45 – 2:15 PMUpdates and Issues in the CPT/RUCProcessR. Patrick Jacob

2:15 – 2:45 PMSurgical Modifiers – With 2011 UpdatesDomagoj Coric

2:45 – 3:30 PM22000 Series – With 2011 UpdatesJohn J. Knightly

3:30 – 4:15 PM63000 Series – With 2011 UpdatesPeter D. Angevine

4:15 – 4:45 PMPeripheral Nerve CodingKarin R. Swartz

4:45 – 5:30 PMDiscussion


SPECIAL COURSE IIMasters in Spinal Surgery: What HasExperience Taught Me?$200 includes lunchCourse Director: Regis W. HaidFaculty: Richard G. Fessler, Ziya L. Gokaslan, Robert F. Heary, Paul C. McCormick, Christopher I. Shaffrey,Vincent C. TraynelisCourse Description: This course willdiscuss the evolution in diagnosis andtreatment of spinal disorders and surgeryfrom the perspective of those that haveextensively contributed to that evolution.Attendees will serve to gain wisdomthrough historical knowledge andexperiential narration.

Learning Objectives: Upon completion ofthis course, participants should be able to: w Synthesize the evolution of spinal

surgery principles and techniques.w Differentiate and apply the treatment

algorithms learned via durable experience and outcomes analysis.

1:30 – 1:50 PMPoint: Grade I Spondylolisthesis withStenosis: Open or Mini-open Is the “Way to Go”Robert F. Heary

1:50 – 2:10 PMCounterpoint: Grade I Spondylolisthesiswith Stenosis: MIS Is the “Way to Go”Richard G. Fessler

2:10 – 2:25 PMDebate and Discussion

2:25 – 2:50 PMHow Do I Decide on Total Tumor Removal vs. Debulking?Ziya L. Gokaslan

2:50 – 3:10 PMIntradural Extramedullary DumbbellTumors: Techniques of Resection (Bone,Intra and Extraforaminal, Dural Closure,etc.)Paul C. McCormick

3:10 – 3:30 PMCervical Deformity: How Do I DecideAmong Anterior, Posterior, Anterior PostCombo (i.e., What Can I Now Do from theFront that I Used to Do Front – Back)Vincent C. Traynelis

3:30 – 3:45 PMBreak

3:45 – 4:15 PM“How High To Go and Where To Stop” inDegenerative Lumbar Scoliosis withStenosisChristopher I. Shaffrey




MEETING AGENDA 23


SPECIAL COURSE III Spinal Deformity$200 includes lunchCourse Directors: Praveen V. Mummaneni,Christopher I. ShaffreyFaculty: Peter D. Angevine, James S. Harrop, Robert F. Heary, Tyler R. Koski, Charles Kuntz, IV, Frank La Marca, David O. Okonkwo,Michael K. Rosner, Amer F. Samdani, Justin S. Smith, Juan UribeCourse Description: This course willdiscuss adult spinal deformity with afocus on the evaluation, classification,and treatment options available to thispatient population. Non-surgicalmanagement options will be noted butemphasis will be placed on surgicalcorrection principles and techniques.Complication management andoperative outcomes will be emphasized.Learning Objectives: Upon completion ofthis course, participants should be able to: w Synthesize and apply the evaluation and classification of adult spinal deformity.

w Identify the various treatment indications and options for adult spinaldeformity.

w Utilize the unique complication avoidance strategies employed during spinal deformity surgery.

1:30 – 1:45 PMCorrection of Cervical KyphosisFrank La Marca

1:45 – 2:00 PMLumbo-Sacro-Pelvic Parameters andFixationPraveen V. Mummaneni

2:00 – 2:15 PMPedicle Subtraction Osteotomy and SmithPetersen Osteotomy: When and HowRobert F. Heary

2:15 – 2:30 PMDirect Lateral Approaches for LumbarSpine Deformity (Lessons Learned)Juan Uribe

2:30 – 2:45 PMWhen To Do Major ReconstructionSurgery vs. Limited Surgery for SpinalDeformityChristopher I. Shaffrey

2:45 – 3:00 PMParkinson’s Disease and Spinal DeformityPeter D. Angevine

3:00 – 3:15 PMMy Worst Spinal Deformity Complicationsand Complication AvoidanceCharles Kuntz, IV

3:15 – 3:30 PMPost-Traumatic Spinal Deformity:Prevention and TreatmentJames S. Harrop

3:30 – 3:45 PMBreak

3:45 – 5:30 PMCases with Complications Praveen V. MummaneniDiscussants: Tyler R. Koski, David O. Okonkwo, Michael K. Rosner,Amer F. Samdani, Justin S. Smith

1:30 – 5:30 PMDesert Conference Suite IV

SPECIAL COURSE IV Advanced MIS Techniques/ManagingMIS Complications$200 includes lunchCourse Directors: Langston T. Holly,Michael Y. WangFaculty: Asdrubal Falavigna, Kevin T. Foley, Anthony Frempong-Boadu, Adam S. Kanter, Paul Park, Mick J. Perez-Cruet, Daniel M. Sciubba,Justin S. SmithCourse Description: This course willdiscuss contemporary data andexperience through MIS case-based,interactive, didactic presentations.Faculty will discuss their evaluations and treatment algorithms regardingminimally invasive vs. open surgicaloptions to maximize complicationavoidance. Focus will be given to casesinitially treated minimally invasively withimmediate or subsequent necessity foropen conversion.Learning Objectives: Followingcompletion of this special course,participants should be able to: w Relate and implement the indications for minimally invasive spinal surgery.

w Distinguish and apply the techniques available for minimally invasive surgery.

w Develop strategies for complication avoidance.

IntroductionLangston Holly

1:30 – 1:50 PM Open vs. Tubular Microdiscectomy: Whatthe Data ShowsAsdrubal Falavigna

1:50 – 2:10 PM Nuances of MIS Cervical Decompression

2:10 – 2:30 PM MIS TLIF: New Technologies for SafeSurgeryMick J. Perez-Cruet

2:30 – 2:50 PM MIS Cervical Fusion and InstrumentationAnthony Frempong-Boadu

2:50 – 3:10 PM XLIF/MIS Lateral Approaches and ItsComplicationsAdam S. Kanter


3:30 – 3:45 PM Break

3:45 – 4:15 PM MIS: What the Past Has Taught Us andWhat the Future HoldsKevin T. Foley

4:15 – 4:30 PM Case Presentation #1Justin S. Smith

4:30 – 4:45 PM Case Presentation #2Paul Park

4:45 – 5:00 PM Case Presentation #3Daniel M. Sciubba

5:00 – 5:30 PM Questions and AnswersMichael Y. Wang



MEETING AGENDA24


SPECIAL COURSE VManagement of Perioperative PainSpecial Course for Nurses, NursePractitioners and Physician Extenders.$110 includes lunchCourse Directors: Michael P. Steinmetz,Andrea L. Strayer, MSN, CNRN, ACNPFaculty: Sanjay S. Dhall, Daniel J. Hoh,Ajit A. Krishnaney, Gregory R. Trost, Luis M. TumialanCourse Description: This course willdiscuss perioperative pain issues withemphasis on up-to-date practical bedsideand outpatient management strategies,with a target audience of nurses, nursepractitioners and physician extenders.Expert practice nurses, physicianassistants, and neurosurgeon faculty willexplore the challenges of caring for ourincreasingly complex patient population.Learning Objectives: Upon completion ofthis course, participants will be able to:w Appraise general postoperative pain

issues following spinal surgery.w Analyze the indications for

postoperative diagnostic studies in patients with extraordinary pain issues following spinal surgery.

w Review and apply care considerations for postoperative pain remote from the surgical site (e.g., voiding difficulties, constipation, etc.).

Physician attendees will not be awarded CMEcredit for this course. Nursing contact hoursmay be provided through AANN. The AmericanAssociation of Neuroscience Nurses is accreditedas a provider of continuing nursing educationby the American Nurses Credentialing Center’sCommission on Accreditation.

Physician assistants/physician extenders willneed to contact their individual membershipassociation and certification board todetermine the requirements for acceptingcredits. All attendees will receive a confirmationof attendance.

1:30 – 2:00 PMPain Pathophysiology, Postoperative Pain,Spine PainSanjay S. Dhall

2:00 – 2:20 PMMechanisms of Action for VariousAnalgesics Including Voiding Issues,Constipation PreventionDaniel J. Hoh

2:20 – 2:40 PMNSAIDS, Review, Contraindictions,OptionsAjit A. Krishnaney

2:40 – 3:05 PMIV vs. Epidular PCALuis M. Tumialan

3:05 – 3:30 PMDo Minimal Access Surgical PatientsHave Less Pain?Michael P. Steinmetz

3:30 – 3:45 PMBreak

3:45 – 4:30 PMRed Flags What Studies, WhenGregory R. Trost

4:30 – 5:00 PMMultimodal TherapyAndrea Strayer, MSN, CNRN, ACNP

5:00 – 5:30 PMPractice Gap Discussion


SPECIAL COURSE VIUpdate on Spinal Surgery in Turkey$200 includes lunchCourse Directors: Selcuk Omer Palaoglu,Mehmet ZileliFaculty: Basar Atalay, Hakan Bozkus,Sedat Cagli, Hakan Caner, Süleyman Çayli, Patrick C. Hsieh, Erkan Kaptanoglu, Cumhur Kilincer,Kemal Koc, Kadir Kotil, Sait Naderi, Fahir Ozer, Timothy F.WithamCourse Description: This course willdiscuss the diagnosis and management ofspinal disorders and surgical solutions inTurkey from the perspective of leadingTurkish spine surgeons. The topics rangefrom surgical approaches andstabilization techniques to motionpreservation surgery and complicationmanagement. Learning Objectives: Followingcompletion of this course, participantsshould be able to:w Analyze the evolution of spinal surgery

principles and techniques in Turkey.w Distinguish some technical nuances of

spinal surgery practiced in Turkey for a variety of spinal conditions

1:30 – 1:40 PMComplication Avoidance and Managementwith Sacral Insufficiency FracturesFollowing Lumbosacral FusionCase Presentation: Timothy F. Witham,Mehmet Zileli

1:40 – 1:50 PMComplication Avoidance and Managementof C5 PalsyCase Presentation: Patrick C. Hsieh,Selcuk Palaoglu

1:50 – 2:10 PMSpine Surgery in Turkey: From Past toPresent Sait Naderi

2:10 – 2:30 PMOblique Corpectomy for CervicalSpondylotic Myelopathy Kemal Koc

2:30 – 2:50 PMPedicle Based Dynamic Fixation Fahir Ozer

2:50 – 3:10 PM Cervical Anterior Foraminotomy Cumhur Kilincer

3:10 – 3:30 PMSurgical Techniques for Upper CervicalSpine InjuriesSedat Cagli

3:30 – 3:45 PMBreak

3:45 – 4:03 PM Anterolateral Retroperitoneal Transiliac(ART) Screw Placement to the FifthLumbar Vertebra: Anatomical Study and aNovel Surgical Approach Erkan Kaptanoglu

4:03 – 4:20 PMUnilateral Pedicle Screw Fixation forMinimally Invasive Transforaminal LumbarInterbody FusionHakan Caner

4:20 – 4:38 PMSurgical Techniques for PosteriorCraniovertebral Junction PathologiesBasar Atalay

4:38 – 4:55 PMTranspedicular Screw Fixation in CervicalFractures Kadir Kotil

4:55 – 5:12 PMLumbar Facet Arthroplasty: Techniques,Biomechanics and Clinical ExperiencesHakan Bozkus

5:12 – 5:30 PMManagement of Congenital Scoliosis Süleyman Çayli



MEETING AGENDA 25

1:30 – 5:30 PMDesert Conference Suite VIII

SPECIAL COURSE VIICervical Myelopathy (co-sponsored by CSRS)$200 includes lunchCourse Directors: James S. Harrop, Robert F. HearyFaculty: Michael G. Fehlings,John G. Heller, Lee H. Riley, Rick Sasso,Vincent C. Traynelis, Jeffrey C. Wang,Timothy F. WithamCourse Description: This course willdiscuss contemporary data andexperience through case-based,interactive, didactic presentations.Faculty will discuss the evaluation andtreatment algorithms regarding cervicalmyelopathy and specifically discusssurgical approaches. Etiology,pathogenesis and diagnosis throughcontemporary imaging modalities willbe explored.Learning Objectives: Followingcompletion of this special course,participants should be able to: w Synthesize appropriate anatomy and biomechanics of the cervical spine.

w Differentiate the methods for diagnosisof neck disorders.

w Apply operative and non-operative treatment options for cervical spine disorders.

w Recognize and respond to complications of surgical treatment.

w Synthesize and apply information on cervical spine research, diagnosis and treatment.

1:30 – 1:31 PMIntroduction and WelcomeJames S. Harrop, Robert F. Heary

1:31 – 1:40 PMPathophysiology of Myelopathy James S. Harrop

1:40 – 1:50 PMMyelopathy at the CVJRick C. Sasso

1:50 – 2:00 PMSubaxial Myelopathy: Anterior TreatmentStrategiesMichael G. Fehlings

2:00 – 2:10 PMSubaxial Myelopathy: Posterior TreatmentStrategiesJohn G. Heller

2:10 – 2:20 PMMyelopathy and CT JunctionTimothy F. Witham

2:20 – 2:30 PMWhy OPLL is SpecialVincent C. Traynelis

2:30 – 2:40 PMImaging and MyelopathyLee H. Riley

2:40 – 2:50 PMWhen Is a Second Procedure Indicated?Jeffrey C. Wang

2:50 – 3:30 PMCase Presentations and Discussion

3:30 – 3:45 PMBreak


T H U R S DAYMARCH 10

6:30 – 6:55 AMGrand Saguaro NorthCase PresentationsModerators: Patrick C. Hsieh, Eve C. Tsai

6:55 – 7:00 AMGrand Saguaro NorthIntroductory Remarks/MeetingAnnouncementsDaryl R. Fourney

7:00 – 9:30 AMGrand Saguaro North

SCIENTIFIC SESSION IEvidence-Based Spine Surgery in theReal WorldModerators: Peter D. Angevine, Michael Y. WangSession Description: This session willexplore how spine surgery has beenaffected by the application of evidence-based medicine, with particular focus oncost-utility analysis and comparativeeffectiveness. Speakers will discuss howthis data can be applied to practice.Additionally, the session will explore howpractice is affected by conflicting orlimited outcomes data.Learning Objectives: Upon completion ofthis session participants should be able to:w Appraise what evidence-based medicine is and how the concept has evolved.

w Relate what cost-utility and comparative effectiveness analyses are and list some examples in spine surgery.

w Analyze how conflicting or limited evidence may be evaluated in a systematic fashion to determine best practice.

7:00 – 7:14 AMCost-Utility AnalysisMatthew J. McGirt

7:14 – 7:27 AMComparative EffectivenessZoher Ghogawala

7:27 – 7:40 AMApplying Base Evidence to PracticeDaniel K. Resnick

OPENING RECEPTION6:00 – 8:00 PM Sage Court

Take in spectacular views of themountains and watch the sunsetwhile enjoying a lavish array of foodand beverages as you network withold friends and new colleagues at theOpening Reception. Please note thisevent is held outdoors. Resort casualattire is recommended.



MEETING AGENDA26

7:40 – 7:53 AMHow To Resolve Clinical Problems with Lack of DataMichael G. Kaiser

7:53 – 8:06 AMHow To Resolve Conflicting Data (e.g., Vertebroplasty)Daryl R. Fourney

8:06 – 8:19 AMEvidence-Based Recommendations forSpine Surgery: How Has the ProcessChanged?Paul C. McCormick

8:19 – 8:32 AMHow To Resolve Cost Conflicts with “Best Evidence”R. Patrick Jacob

8:32 – 8:45 AMHow To Resolve Reimbursement Conflictswith “Best Evidence”Joseph S. Cheng

8:45 – 8:50 AMIntroduction of Section ChairpersonDaryl R. Fourney

9:05 – 9:10 AMIntroduction of Meritorious Service AwardRecipientMichael G. Fehlings

9:30 – 10:15 AMGrand Canyon BallroomBEVERAGE BREAK WITH EXHIBITORS

What’s New Session IModerators: Dean Karahalios, Daniel M. Sciubba

10:15 AM – 12:30 PMGrand Saguaro North

ORAL PLATFORM PRESENTATIONS IModerators: Ali Bydon, Praveen V. MummaneniDiscussants: Joseph T. Alexander, Michael W. Groff, R. John Hurlbert, Iain H. Kalfas, Mark R. McLaughlin, Daniel K. Resnick, Gregory R. Trost,Christopher E. Wolfla, Eric L. Zager

10:15 – 10:24 AM100. In Situ Placement of High-doserhBMP-2 within Spine Tumors SlowsTumor Growth and Decreases Onset toParalysis in a Rat Model of MetastaticBreast CancerCamilo A. Molina, Rachel Sarabia-Estrada,Guergana Panayotova, Antonio Aguilera,Ziya L. Gokaslan, Jean-Paul Wolinksy, Ali Bydon, Daniel M. Sciubba

10:24 – 10:27 AMDiscussant: Eric L. Zager

10:27 – 10:36 AM101. The Effect of Surgery on HealthRelated Quality of Life and FunctionalOutcome in Patients with MetastaticEpidural Spinal Cord Compression InitialResults of the AOSpine North AmericaProspective Multicenter StudyMichael G. Fehlings, Branko Kopjar,Alexander R. Vaccaro, Paul M. Arnold,Charles Fisher, Ziya L. Gokaslan, James M. Schuster, Mark B. Dekutoski, Joel Finkelstein, Laurence D. Rhines

10:36 – 10:39 AMDiscussant: Iain H. Kalfas

10:39 – 10:48 AM102. Survival of Patients with MalignantPrimary Osseous Spinal Neoplasms fromthe Surveillance, Epidemiology, and EndResults (SEER) Database from 1973-2005Kaisorn L. Chaichana, Scott Parker,Owoicho Adogwa, Debraj Mukherjee,Oran Aaronson, Joseph S. Cheng, Ziya L. Gokaslan, Matthew J. McGirt

10:48 – 10:51 AMDiscussant: Christopher E. Wolfla

10:51 – 11:00 AM103. Electrical Stimulation Enhances Axonand Nerve RegenerationRajiv Midha, Bhagat Singh, Qing Gui Xu,Colin Franz, Colin Dalton, Tessa Gordon,Doug Zochodne

11:00 – 11:03 AMDiscussant: Michael W. Groff

11:03 – 11:16 AMDiscussion

11:16 – 11:25 AM104. Efficacy and Active Ingredients in anEpidural Analgesic Paste after LumbarDecompression: A ProspectiveRandomized Double-Blind Controlled Trial.Roberto Jose Diaz, S. Terence Myles, R. John Hurlbert

11:25 – 11:28 AMDiscussant: Mark R. McLaughlin

11:28 – 11:37 AM105. Radiographic Same-level RecurrentDisc Herniation After Lumbar Discectomy:Prospective Longitudinal Study with Two-year Follow-upScott Parker, Richard L. Lebow, Owoicho Adogwa, Adrija Sharma, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirt

11:37 – 11:40 AMDiscussant: Joseph T. Alexander

11:40 – 11:49 AM106. Cost Effectiveness of MultilevelHemilaminectomy for Lumbar StenosisAssociated RadiculopathyErin Fulchiero, Brandon J. Davis, Owoicho Adogwa, Oran Aaronson, Joseph S. Cheng, Clint Devin, Matthew J. McGirt

11:49 – 11:52 AMDiscussant: Daniel K. Resnick

11:52 AM – 12:01 PM107. Provocative Discography ScreeningImproves Surgical OutcomePetra Margetic, Marin F. Stancic

12:01 – 12:04 PMDiscussant: R. John Hurlbert

12:04 – 12:13 PM108. The Impact of Surgeon ProfessionalFees to the National Cost of HealthcareCamilo A. Molina, Ziya L. Gokaslan,Timothy F. Witham, Ali Bydon, Jean-Paul Wolinsky, Daniel M. Sciubba

9:10 – 9:30 AM

MERITORIOUSSERVICE AWARDPRESENTATION

QuestionAuthority or a CriticalLook at Things We Take for Granted

Paul R. Cooper

8:50 – 9:05 AM

PRESIDENTIALADDRESS

Evolution of Surgical Treatment

Ziya L. Gokaslan



MEETING AGENDA 27

12:13 – 12:16 PMDiscussant: Gregory R. Trost


12:30 – 1:25 PMGrand Canyon BallroomLUNCH WITH EXHIBITORS

What’s New Session IIModerators: Michael P. Steinmetz, John Chi

1:25 – 1:30 PMGrand Saguaro NorthMeeting AnnouncementsPraveen V. Mummaneni

1:30 – 3:00 PMGrand Saguaro North

SCIENTIFIC SESSION IISpinal Surgery ComplicationAvoidance and ManagementModerators: R. John Hurlbert, Eve C. TsaiCourse Description: This course willaddress the complications encounteredin a case-based format with attention tomanagement techniques and learnedavoidance strategies. Cases willspecifically address complicationsencountered during minimally invasiveprocedures, vertebral artery injury,intradural tumors, lumbar fusion,transpsoas approaches and anteriorcervical approaches.Learning Objectives: Upon completion ofthis course, participants should be able to:w Identify risk factors associated with spinal surgery complications.

w Create surgery planning strategies to avoid complications.

w Develop intraoperative strategies to avoid complications.

w Incorporate postoperative strategies to avoid complications.

1:30 – 1:33 PMMIS Complication Case – IntroductionDaniel M. Sciubba

1:33 – 1:43 PMMIS Complication Case – DiscussionMichael Y. Wang

1:43 – 1:46 PMComplication Avoidance and Managementwith Vertebral Artery Injury – IntroductionDean Karahalios

1:46 – 1:56 PMComplication Avoidance and Managementwith Vertebral Artery Injury – DiscussionVolker K.H. Sonntag

1:56 – 1:59 PMComplication Avoidance and Managementwith BMP Interbody in the Lumbar Spine –IntroductionSrinivas K. Prasad

1:59 – 2:09 PMComplication Avoidance and Managementwith BMP Interbody in the Lumbar Spine –DiscussionJames S. Harrop

2:09 – 2:12 PMComplication Avoidance and Managementwith Intraoperative Monitoring Changeswith Intradural Tumors – IntroductionGeorge I. Jallo

2:12 – 2:22 PMComplication Avoidance and Managementwith Intraoperative Monitoring Changeswith Intradural Tumors – DiscussionR. John Hurlbert

2:22 – 2:25 PMComplication Avoidance and Managementwith Sacral Insufficiency FracturesFollowing LS Fusion – IntroductionTimothy F. Witham

2:25 – 2:35 PMComplication Avoidance and Managementwith Sacral Insufficiency FracturesFollowing LS Fusion – DiscussionMehmet Zileli

2:35 – 2:38 PMComplication Avoidance and Managementwith Transpoas Approaches (Nerve Injury) –IntroductionAdam S. Kanter

2:38 – 2:48 PMComplication Avoidance and Managementwith Transpoas Approaches (Nerve Injury) –DiscussionAllan J. Belzberg

2:48 – 2:51 PMComplication Avoidance and Managementwith C5 Palsy – IntroductionPatrick C. Hsieh

2:51 – 3:00 PMComplication Avoidance and Managementwith C5 Palsy – DiscussionSelcuk Omer Palaoglu

3:00 – 3:45 PMGrand Canyon BallroomBEVERAGE BREAK WITH EXHIBITORS

What’s New Session IIIModerators: Sanjay S. Dhall, Matthew J. McGirt

3:45 – 5:15 PMGrand Saguaro North

ORAL POSTER PRESENTATIONS I (Concurrent Sessions)Moderators: Dean Chou, Justin S. Smith

3:45 – 3:50 PM200. Pulsed Electromagnetic Field BoneGrowth Stimulation for High Risk FusionPatients: An Analysis of 452 ConsecutiveCasesNaresh P. Patel, Barry D. Birch, Mark K. Lyons, Richard S. Zimmerman,Stacie DeMent, Gregg Elbert, Orland K. Boucher, Amy Theiler

3:50 – 3:55 PM201. Preservation of Segmental Motionwith Anterior Contralateral CervicalMicrodiskektomy and Interbody Fat Graft:Prospective StudyYunus Aydin, Halit Çavusoglu, Cengiz Tuncer, Osman Nuri Türkmenoglu,Ahmet Murat Müslüman

3:55 – 4:00 PM202. Radiographic Outcomes in Two-levelACDFs: Comparison of PEEK and AllograftInterbody Devices at 1 and 2 Year Follow-upJody A. Rodgers, W.B. Rodgers, Edward J. Gerber

4:00 – 4:05 PM203. Safety, Efficacy, and Dosing ofRecombinant Human Bone MorphogeneticProtein-2 (rhBMP-2) for PosteriorCervical and Cervico-thoracicInstrumented Fusion with a MinimumTwo-year Follow-upD. Kojo Hamilton, Justin S. Smith, Davis Reames, Brian Jeremy Williams,Daniel R. Chernavvsky, Christopher I. Shaffrey

4:05 – 4:10 PM204. Prospective Results from the US IDEFeasibility Study of a Novel Peek-On-Peek Nucleus Replacement Device withMinimum Two-Year Follow-upDomagoj Coric, Matthew Songer, John J. Regan



MEETING AGENDA28


4:15 – 4:20 PM205. Preoperative Grading Scale toPredict Survival in Patients UndergoingResection of Malignant Primary OsseousSpinal NeoplasmsScott Parker, Kaisorn L. Chaichana, Oran Aaronson, Joseph S. Cheng, Ziya L. Gokaslan, Matthew J. McGirt

4:20 – 4:25 PM206. Clinical Outcomes Following En BlocSacrectomies via Posterior ApproachMichelle J. Clarke, Daniel M. Sciubba,Matthew J. McGirt, Timothy F. Witham, Ali Bydon, Patrick C. Hsieh, Ziya L. Gokaslan, Jean-Paul Wolinsky

4:25 – 4:30 PM207. Generation of Chordoma Cell Line,JHC7, and the Identification of Brachyuryas a Novel Molecular TargetWesley Hsu, Ahmed Mohyeldin, Sagar R. Shah, Lakesha Johson, Neda I. Sedora-Roman, Thomas Kosztowski, Colette Ap Rhys, Ola Awad, Edward McCarthy, David Loeb,Jean-Paul Wolinsky, Ziya L. Gokaslan,Alfredo Quinones-Hinojosa

4:30 – 4:35 PM208. Reconstruction of Extensive Defectsfrom Posterior En Bloc Resection ofSacral Tumors Using Human AcellularDermal Matrix and Gluteus MaximusMyocutaneous FlapsHormuzdiyar H. Dasenbrock, Michelle J. Clarke, Ali Bydon, Timothy F. Witham, Daniel M. Sciubba,Oliver P. Simmons, Ziya L. Gokaslan, Jean-Paul Wolinsky

4:35 – 4:40 PM243. Clinical Outcome and Risk ofReoperation for Recurrent TCS in 99Consecutive Children Operated for Tightor Fatty FilumLauren Rose Ostling, Karin S. Bierbrauer,Charles Kuntz, IV


4:45 – 4:50 PM210. Identification of Cancer Stem Cells inHuman ChordomaWesley Hsu, Ahmed Mohyeldin, Sagar R. Shah, Thomas Kosztowski,Lakesha Johnson, Ola Awad, Neda I. Sedora-Roman, David Loeb,Edward McCarthy, Jean-Paul Wolinsky,Ziya L. Gokaslan, Alfredo Quinones-Hinojosa

4:50 – 4:55 PM211. Sacral Laminoplasty for theTreatment of Symptomatic SacralPerineural (Tarlov) Cysts, ClinicalOutcomes and Surgical ObservationsZachary Adam Smith, Larry T. Khoo

4:55 – 5:00 PM212. Hydrostatic Strength Dural PatchRepair MaterialsMichael A. Finn, Paul Anderson, Nathan Faulkner

5:00 – 5:05 PM213. Hydrostatic Comparison of TitaniumClip and Suture Repair of DurotomyMichael A. Finn, Paul Anderson, Nathan Faulkner

5:05 – 5:10 PM214. Prospective Randomized ControlledTrial in Spine Patients to Compare LowSwell Formulation of a PolyethyleneGlycol Hydrogel Spinal Sealant with OtherMethods of Dural SealingKee Duk Kim, Joseph S. Cheng, Randall Matthew Chesnut, Dean Chou,Haroon F. Choudhri, Garth Rees Cosgrove,Shankar Prakash Gopinath, R. Scott Graham, Richard Gray, Ajit A. Krishnaney, Paul C. McCormick,Ehud Mendel, Jon Park, Mark Edwin Shaffrey,Nathan E. Simmons,John M. Tew, Jr., Jack E. Wilberger, Jr., Neill Marshall Wright



ORAL POSTER PRESENTATIONS II (Concurrent Sessions)Moderators: John Chi, Marjorie C. Wang

3:45 – 3:50 PM215. Assessment of Thoracic LaminarDimensions in a Pediatric Population: A CT-Based Feasibility Study for PediatricThoracic Translaminar Screw PlacementCamilo A. Molina, Christopher Chaput,Daniel M. Sciubba, P. Justin Tortolani,George I. Jallo, Ryan M. Kretzer

3:50 – 3:55 PM216. CT Hounsfield Units for AssessingBone Mineral Density: A Tool ForOsteoporosis ManagementPaul A. Anderson, Joseph Schreiber

3:55 – 4:00 PM217. Effects of Epidural Steroid Injectionson Blood Glucose Levels in Patients withDiabetes MellitusOwoicho Adogwa, Jesse Even, Kirk McCullough, Clint Devin, Matthew J. McGirt

4:00 – 4:05 PM218. The Prognostic Value of a CervicalSelective Nerve Root Block: A Correlationwith Surgical OutcomesLuis M. Tumialan, David C. LoPresti,Angelina N. Garvin, Wayne Gluf

4:05 – 4:10 PM219. The Prognostic Value of a LumbarSelective Nerve Root Block: A Correlationwith Surgical OutcomesLuis M. Tumialan, David C. LoPresti,Angelina N. Garvin, Wayne Gluf


4:15 – 4:20 PM220. Proximal Junctional Kyphosis inAdult Thoracolumbar InstrumentedFusion: Time to Development, Clinical andRadiographic Characteristics, andManagement Approach in 32 ConsecutiveCasesDavis Reames, Justin S. Smith, D. Kojo Hamilton, Vincent Arlet,Christopher I. Shaffrey

4:20 – 4:25 PM221. Direct Vertebral Body Derotation: AComparison of Different TechniquesAmer F. Samdani, Steven Wei-Hung Hwang,Michelle Marks, Tracey Bastrom, Randal Betz, Patrick Cahill



MEETING AGENDA 29

4:25 – 4:30 PM222. Direct Vertebral Body Derotation,Thoracoplasty or Both: Which is Betterwith Respect to Inclinometer and SRS-22Scores?Amer F. Samdani, Steven Wei-Hung Hwang,Peter Newton, Baron Lonner, Michelle Marks, Tracey Bastrom, Patrick Cahill, Randal Betz

4:30 – 4:35 PM223. Differences in Treatment andInpatient Outcomes for HospitalizedScoliosis Patients in the United Statesfrom 1998 to 2007Doniel Drazin, Miriam Nuno, Frank L. Acosta, Jr.

4:35 – 4:40 PM224. The Safety and Efficacy ofTransforaminal Lumbar Interbody Fusionfor Deformity Correction in DegenerativeScoliosis with Spinal StenosisAlan T. Villavicencio, Ewell Lee Nelson,Alexander Mason, Sharad Rajpal, Frances A. Carr, Sigita Burneikiene


4:45 – 4:50 PM225. Biomechanical Analysis of IliacScrews vs. S2 Alar-Iliac ScrewsCyrus Chi-Ho Wong, Chase Corn, Colin Crosby, Jesse Even, Gregory A. Mencio,Clinton J. Devin, Matthew J. McGirt

4:50 – 4:55 PM226. Reduced Surgical Site Infections inPatients Undergoing Posterior SpinalStabilization of Traumatic Injuries UsingVancomycin PowderOwoicho Adogwa, Kevin O’Neill, Jason S. Smith, Amir Abtahi, Kristen Archer-Swygert, Clint Devin,Matthew J. McGirt

4:55 – 5:00 PM227. Intraoperative Glucose Levels and itsAssociation with Developing PostoperativeSurgical Site Infections Following SpineSurgeriesFrances Mao, Ajit A. Krishnaney

5:00 – 5:05 PM228. Multiple-day Drainage when UsingBMP for Long Segment Thoraco-lumbarInstrumented Fusions Results in LowReoperation Rates for Infection andSeromaDwight Saulle, Kai-Ming G. Fu, Justin S. Smith, Christopher I. Shaffrey

5:05 – 5:10 PM229. Efficacy of Prophylactic PreoperativeInferior Vena Cava Filters for Major SpinalSurgery in Adults: A Review of 219Patients at a Single InstitutionJamal McClendon, Jr., Brian A. O’Shaughnessy, Timothy R. Smith,Patrick Alexander Sugrue, Ryan J. Halpin,Tyler R. Koski, Stephen L. Ondra


F R I D A YMARCH 11

6:30 – 7:00 AMGrand Saguaro NorthCase PresentationsModerator: David J. Hart, Daniel C. Lu


SCIENTIFIC SESSION IIIEvolution of Treatment for MetastaticDiseaseModerators: Daryl R. Fourney, Laurence D. RhinesSession Description: This session willreview the natural history andmanagement of metastatic spinal tumors.Clinical and radiographic assessment aswell as current treatments including MISand radiosurgery will be discussed. Thecosts of care for this complex patientpopulation will also be discussed.Learning Objectives:Upon completion of this session, participants should beable to:w Assimilate the significance of tumor biology, neurology, patient fitness and mechanical stability in considering management options.

w Analyze the indications and techniquesfor metastatic spine tumors.

w Relate costs of care and how treatment impacts the quality of life.

7:00 – 7:15 AMMIS/Vertebroplasty/Hybrid TechniquesEhud Mendel

7:15 – 7:30 AMRadiosurgeryJack P. Rock

7:30 – 7:45 AMQuestions for the Panel

7:45 – 8:00 AMRole of En Bloc vs. Piecemeal forMetastatic Tumors of the SpineStefano Boriani

8:00 – 8:15 AMEvolution of Surgery for MetastaticDiseaseZiya L. Gokaslan

8:15 – 8:30 AMCost Utility Analysis and the Role ofSurgery for Metastatic Spine Disease inthe ElderlyDean Chou

8:30 – 8:45 AMThe Future: AnimalModels/Technology/Biologic StrategiesDaniel M. Sciubba

8:45 – 9:00 AMQuestions for the Panel

9:00 – 9:30 AMGrand Saguaro NorthMAYFIELD AWARDS AND PRESENTATIONSModerators: Adam S. Kanter, Marjorie C. WangDiscussants: Adam S. Kanter, Daniel M. Sciubba, Marjorie C. Wang

9:00 – 9:08 AMMAYFIELD BASIC SCIENCE AWARDEvidence of Descending SupraspinalControl of Nociception and Pain Behaviorin Experimental Disc-HerniationRadiculopathyMohammed F. Shamji, Priscilla Hwang,Kyle D. Allen, Mosfata Gabr, J. Chen,Liufang Jing, William J. Richardson, Lori A. Setton

9:08 – 9:10 AMDiscussant: Daniel M. Sciubba

RECEPT ION WITHTHE EXH I B I TOR S

5:15 – 6:45 PMGrand Canyon Ballroom

Join us for this special event in theexhibit hall! Interact with colleaguesand corporate contacts while enjoyingpre-dinner cocktails and hors d’oeuvres.Business casual attire is recommended.



MEETING AGENDA30

9:10 – 9:18 AMMAYFIELD CLINICAL SCIENCE AWARDPerioperative Use of Dexamethasone inMultilevel Anterior Cervical SpineSurgery: Preliminary Results of aProspective, Randomized, Double-BlindedTrialTyler J. Kenning, Karen Petronis, John W. German, Doniel Drazin, Darryl J. Dirisio

9:18 – 9:20 AMDiscussant: Adam S. Kanter

9:20 – 9:28 AMOUTCOMES COMMITTEE AWARDAnalysis of the Three United States FDA-IDE Cervical Arthroplasty TrialsCheerag Upadhyaya, Jau-Ching Wu, Regis W. Haid, Jr., Vincent C. Traynelis,Bobby Tay, Domagoj Coric, Gregory R. Trost, Scott A. Meyer, Praveen V. Mummaneni

9:28 – 9:30 AMDiscussant: Marjorie C. Wang


What’s New Session IVModerators: Dean Chou, Justin S. Smith


ORAL PLATFORM PRESENTATIONS IIModerators: Langston T. Holly, Frank La MarcaDiscussants: Paul M. Arnold, Charles L. Branch, Mark N. Hadley,Charles Kuntz, IV, David O. Okonkwo,Gerald E. Rodts, Jr., Michael K. Rosner,Brian R. Subach, Eric J. Woodard

10:15 – 10:24 AM109. Effect of Patient Pain Expectationsand Preoperative SF-36 MentalComponent Summary Scores on ClinicalOutcomes Following Anterior CervicalDiscectomy and FusionFrances A. Carr, Theresa Hernandez, Kyle M. Healy, Ewell Lee Nelson, Alexander Mason, Sigita Burneikiene, Alan T. Villavicencio

10:24 – 10:27 AMDiscussant: Charles L. Branch

10:27 – 10:36 AM110. Factors Associated with theOccurrence of Perioperative Complicationsin the Treatment of Cervical SpondyloticMyelopathy Based on 302 Patients fromthe AOSpine North America CervicalSpondylotic Myelopathy StudyJustin S. Smith, Christopher I. Shaffrey,Branko Kopjar, Paul M. Arnold, Sangwook Yoon, Alexander R. Vaccaro,Darrel S. Brodke, Michael Janssen, Jens Chapman, Rick Sasso, Eric J. Woodard, Robert J. Banco, Eric M. Massicotte, Mark Dekutowski, Ziya L. Gokaslan, Christopher Bono,Michael G. Fehlings

10:36 – 10:39 AMDiscussant: Mark N. Hadley

10:39 – 10:48 AM111. Comparative Economic Analysis ofVentral vs. Dorsal Surgery for CervicalSpondylotic MyelopathyAndrew Becker, Robert Gray Whitmore,Susan Christopher, Jill Curran, Benjamin Baskin, Zoher Ghogawala

10:48 – 10:51 AMDiscussant: Gerald E. Rodts, Jr.

10:51 – 11:00 AM112. Functional and Quality of LifeOutcomes in Geriatric Patients with TypeII Odontoid Fracture: One-Year Resultsfrom the AOSpine North America Multi-Center GOF Prospective StudyMichael G. Fehlings, Alexander R. Vaccaro,Branko Kopjar, Jens Chapman,Christopher I. Shaffrey, Paul M. Arnold,Ziya L. Gokaslan, Roger Hartl, Darrel S. Brodke, John France, Sangwook Yoon, Mark B. Dekutoski, Rick Sasso, Christopher Bono

11:00 – 11:03 AMDiscussant: Eric J. Woodard


11:09 – 11:18 AM113. Prospective, Randomized, MulticenterStudy of Cervical Arthroplasty: 269Patients from the Kineflex/C Metal-on-Metal Artificial Disc IDE Study withMinimum Two-Year Follow-upDomagoj Coric, Richard D. Guyer, Pierce D. Nunley, Charley Gordon, Thomas Dimmig, Cameron Carmody,Donna D. Ohnmeiss, Margaret Boltes

11:18 – 11:21 AMDiscussant: Paul M. Arnold

11:21 – 11:30 AM114. Cervical Disc Replacement: InterimFive-year Follow-up Results from theUnited States Prospective RandomizedBryan Clinical TrialRichard G. Fessler, Rick Sasso, Paul Anderson, John Heller

11:30 – 11:33 AMDiscussant: Brian R. Subach

11:33 – 11:42 AM115. Are Closed Suction Drains inPosterior Spinal Surgery “The Devil’sHighway” for Infection?James S. Harrop, Srinivas K. Prasad, John Kevin Ratliff, Mitchell Gil Maltenfort,Phyllis Flomenberg, Ashwini Dayal Sharan,Alex Vaccaro, Shilpa Rao

11:42 – 11:45 AMDiscussant: Michael K. Rosner

11:45 – 11:54 AM116. Clinical and Radiographic FactorsDriving the Transition from Nonoperative toOperative Treatment in Elderly Adults withDegenerative ScoliosisKai-Ming G. Fu, Justin S. Smith,Christopher I. Shaffrey

11:54 – 11:57 AMDiscussant: Charles Kuntz, IV

11:57 AM – 12:06 PM117. Incidence of Vascular EncroachmentResulting from Free Hand Placement ofPedicle Screws in the Thoracic andLumbar Spine: Analysis of 6,816Consecutive ScrewsScott L. Parker, Anubhav Amin, Ali Bydon,Daniel M. Sciubba, Jean-Paul Wolinsky,Ziya L. Gokaslan, Timothy F. Witham

12:06 – 12:09 PMDiscussant: David O. Okonkwo


12:15 – 12:20 PMMeeting AnnouncementsDaryl R. Fourney, Praveen V. Mummaneni

12:20 – 12:30 PMGrand Saguaro NorthANNUAL BUSINESS MEETINGPresiding Officer: Ziya L. GokaslanModerator: Michael W. Groff



MEETING AGENDA 31


LUNCHEON SYMPOSIUM IRevision Spine Surgery$200 includes lunchCourse Directors: Michael W. Groff, Iain H. KalfasFaculty: David O. Okonkwo, Timothy C. RykenCourse Description: This course willprovide state-of-the-art information oncomplication avoidance during revisionspine surgery. Faculty will review theirclinical experience and lessons learnedvia interactive case discussions.Learning Objectives: Upon completion ofthis course, participants should be able to:w Explain the management issues uniqueto revision surgery.

w Appraise the common reasons for spinal instrumentation failure.

w Evaluate the management of recurrent spinal conditions such as restonosis and reherniation and apply to practice.

w Integrate strategies for the managementof postoperative deformity and adjacent segment failure.

12:30 – 12:50 PMBiomechanics of Spinal InstrumentationTimothy C. Ryken

12:50 – 1:10 PMManagement of Recurrent LumbarStenosis and/or Disc HerniationDavid O. Okonkwo

1:10 – 1:30 PMManagement of Adjacent Segment FailureMichael W. Groff

1:30 – 1:45 PMBreak

1:45 – 2:05 PMManagement of Iatrogenic CervicalDeformityIain H. Kalfas



LUNCHEON SYMPOSIUM IINeurosurgeon as CEO: BusinessAspects of Spinal Surgery$200 includes lunchCourse Directors: Domagoj Coric, John J. KnightlyFaculty: E. Hunter Dyer, Mark R. McLaughlinCourse Description: This course willexamine neurosurgery from thephilosophy of the small businessoperation. It will review the basics ofrevenue generation, transactions withthird-party payors, marketing, andoperations including management ofexpenses and personnel. Learning Objectives: Upon completion ofthis course, participants should be able to:w Differentiate the mechanisms of revenue generation as well as critically examine future scenarios to change in revenue generation.

w Critically examine operations includingcosts, personnel and efficiency.

w Distinguish and apply different management paradigms for small business.

12:30 – 12:50 PMRevenue Generation: Ancillary Income-Surgicenter/Imaging CenterDomagoj Coric


1:00 – 1:20 PMMarketing Your PracticeMark R. McLaughlin


1:30 – 1:45 PMBreak

1:45 – 2:05 PMEfficiency in Operations:Personnel/ExpensesE. Hunter Dyer

2:05 – 2:25 PMThird Party Payors - NegotiationsJohn J. Knightly



LUNCHEON SYMPOSIUM IIICranial-Cervical Junction$200 includes lunchCourse Directors: Curtis A. Dickman,Jean-Paul WolinskyFaculty: Christopher P. Ames, Dean Chou,Arnold H. Menezes, Volker K.H. SonntagCourse Description: This course willdiscuss contemporary data andexperience in treating pathology of thecranial-cervical junction. This course willbe in a case-based interactive format withdidactic presentations. Faculty willdiscuss their evaluation and treatmentalgorithms surrounding pathology of theCCJ. The focus will be on understandingthe pathophysiology of variousconditions and how treatment strategieshave evolved with better understandingof this region.Learning Objectives:Upon completion ofthis course, participants should be able to:w Relate how certain pathologic processes effect the cranial-cervical junction.

w Distinguish why certain treatment strategies are implemented and understand the basic surgical techniques for specific pathologic processes.

w Develop and design complex reconstructions of the cranial-cervical junction.

12:30 – 12:45 PMPathology of the Craniocervical Junctionand Closed and Open ReductionTechniquesDean Chou

12:45 – 1:00 PMTransoral and Extended TransoralProceduresArnold H. Menezes

1:00 – 1:15 PMTransnasal ApproachChristopher P. Ames

1:15 – 1:30 PMTranscervical ApproachJean-Paul Wolinsky

1:30 – 1:45 PMBreak

1:45 – 2:00 PMTraumatic Dislocations of theCraniocervical JunctionVolker K.H. Sonntag



MEETING AGENDA32

2:00 – 2:15 PMOccipital Cervical InstrumentationCurtis A. Dickman



LUNCHEON SYMPOSIUM IVGeriatric Spine$200 includes lunchCourse Directors: James S. Harrop,Gregory R. TrostFaculty: Daniel Robert Fassett, Shaun T. O’Leary, Srinivas K. Prasad,Daniel M. Sciubba, Michael P. SteinmetzCourse Description: This course willreview degenerative disease from theperspective of the aging spine. It willexamine basic spinal pathology anddetermine what effects these processeswill have in regards to surgical and non-surgical management in the elderly, aswell as their societal and economicimpact.Learning Objectives: Upon completion ofthis course, participants should be able to: w Appraise the complexities when dealing with geriatric patients with spinal disorders, specifically focusing on osteoporosis, odontoid fractures, and traumatic central cord injuries.

w Determine how diseases of the aging shift treatment protocols and the modification that may be employed forthe surgical and non-surgical management of the aging spine.

12:30 – 12:35 PMIntroduction Gregory R. Trost

12:35 – 12:45 PMOsteoporosis and Surgery James S. Harrop

12:45 – 12:55 PMDegenerative Srinivas K. Prasad

12:55 – 1:10 PMDegenerative Deformity Daniel Robert Fassett

1:10 – 1:20 PMTrauma - Odontoid Fractures Type II vs. Type III Daniel M. Sciubba

1:20 – 1:30 PMTrauma - Central Cord Injuries Shaun T. O’Leary

1:30 – 1:40 PMTrauma – VCF Michael P. Steinmetz

1:40 – 2:30 PMCase Presentations


LUNCHEON SYMPOSIUM VSpinal Arthroplasty$200 includes lunchCourse Directors: Regis W. Haid, Praveen V. MummaneniFaculty: Domagoj Coric, Robert J. Hacker,Brian R. SubachCourse Description: Participants in thiscourse will review outcome data ofcervical and lumbar arthroplasty. Pearlsand pitfalls of experienced surgeons willbe discussed. Complications and theiravoidance will be outlined. A comparisonbetween arthroplasty and arthrodesis willbe elucidated.Learning Objectives: Upon completion ofthis course, participants should be able to: w Appraise the indications and contraindications for arthroplasty.

w Assimilate the associated complications and management strategies for them.

12:30 – 12:50 PMCurrent Status and Outcomes of LumbarArthroplastyBrian R. Subach

12:50 – 1:10 PMCurrent Status and Outcomes of CervicalArthroplastyDomagoj Coric

1:10 – 1:30 PMLessons Learned in Cervical ArthroplastyRobert J. Hacker

1:30 – 1:45 PMBreak

1:45 – 2:00 PMUpdate on Cervical Arthoplasty StudiesPraveen V. Mummaneni

2:00 – 2:30 PMCase Discussion

1:30 – 5:30 PMDesert Conference Suite III

SPECIAL COURSE VIIIPeripheral Nerve Exposures and NerveRepair TechniquesComplimentary for Resident Members$200 includes lunchCourse Directors: Robert J. Spinner, Lynda Jun-San YangFaculty: Allan J. Belzberg, Marie-Noëlle Hébert-Blouin, Line Jacques,Rajiv Midha, Shaun T. O’Leary, Eric L. ZagerCourse Description: This course willdemonstrate the common exposures toperipheral nerves in the upper extremityand common techniques used forperipheral nerve reconstruction. It istargeted to practicing surgeons, seniorresidents and fellows.Learning Objectives: Upon completion ofthis course, participants should be able to:w Synthesize the pertinent and practical surgical anatomy of the brachial plexusand peripheral nerves in the upper limb as related to common nerve injuries, nerve entrapments, and other nerve disorders.

w Distinguish common techniques utilized in the reconstruction of peripheral nerves (direct repair, grafting, nerve transfers, and nerve conduits).

This course will prepare residents for writtenboard examinations and young neurosurgeonsfor oral board examinations.

1:30 – 1:45 PMExposure to the Supraclavicular BrachialPlexusRobert J. Spinner


1:50 – 2:05 PMExposure to the Infraclavicular BrachialPlexusLynda Jun-San Yang


2:10 – 2:40 PMRadial and Ulnar Nerve ExposuresEric L. Zager


2:45 – 3:00 PMMedian Nerve ExposuresLine Jacques



MEETING AGENDA 33

3:00 – 3:20 PMApproaches to the Axillary andSuprascapular NervesMarie-Noëlle Hébert-Blouin


3:30 – 3:45 PMBreak

3:45 – 4:10 PMLower Extremity ExposuresShaun T. O’Leary


4:15 – 4:40 PMTechniques for NerveRepair/ReconstructionRajiv Midha

4:40 – 5:10 PMTechniques for Common Nerve TransfersAllan J. Belzberg

5:10 – 5:30 PMCases

1:30 – 5:30 PMDesert Conference Suite IV

SPECIAL COURSE IXEvaluation and Management of theSpine Trauma PatientSpecial Course for Nurses, NursePractitioners and Physician Extenders. $110 includes lunchCourse Directors: Mark Edwin Shaffrey,Andrea L. Strayer, MSN, CNRN, ACNPFaculty: Sanjay S. Dhall, Jeffrey R. Holtz, PA,Adam S. Kanter, David O. Okonkwo,Charles A. Sansur, Justin S. Smith, Eve C. TsaiCourse Description: This course willprovide practical, current didacticinformation on spine trauma withparticular emphasis on an update onmedical therapies and intensive care aftera complete injury; radiographicinterpretation and classification schemesof cervical as well as thoracolumbarfractures. Interactive case presentationswill illustrate treatment and careconsiderations. Expert faculty will explorethe challenges of caring for this complexpatient population. Learning Objectives: Upon completion ofthis course, participants will be able to:w Analyze current evidence regarding steroid therapy and hypothermia after SCI.

w Evaluate radiographic evaluation following spinal trauma and classification of fracture types.

w Distinguish radiographic evidence as well as care considerations for facet fractures, ligamentous injury, and upper cervical spine including odontoid fractures.

w Develop and apply ICU care considerations following a complete SCI.

Physician attendees will not be awarded CMEcredit for this course. Nursing contact hours willbe provided through AANN. The AmericanAssociation of Neuroscience Nurses is accreditedas a provider of continuing nursing educationby the American Nurses Credentialing Center’sCommission on Accreditation.

Physician Assistants/Physician Extenders willreceive credit for attendance. Each physicianassistant/physician extenders will need tocontact his or her individual membershipassociation and certification board todetermine the requirements for acceptingcredits. All attendees will receive a confirmationof attendance.

1:30 – 2:00 PMSteroid Therapy and HypothermiaDavid O. Okonkwo

2:00 – 2:35 PMO – C2: Radiographs, Classification,Nonoperative vs. OperativeCharles A. Sansur

2:35 – 3:05 PMSubaxial: Radiographs, Classification,Nonoperative vs. OperativeJustin S. Smith

3:05 – 3:30 PMComplete SCI – ICU Evidence and PearlsSanjay S. Dhall

3:30 – 3:45 PMBreak

3:45 – 4:30 PMT/L Trauma ManagementAdam S. Kanter

4:30 – 4:50 PMCare Consideration of the T/L Junction;Including Neuro/B/B/PostoperativeJeffrey R. Holtz, PA

4:50 – 5:30 PMSCI – What Does the Future Hold? Eve C. Tsai

S ATU R D AYMARCH 12

6:30 – 6:55 AMGrand Saguaro NorthCase PresentationsModerators: Meic H. Schmidt, Jau-Ching Wu


ORAL POSTER SESSION IIIModerators: Yevgeniy Khavkin, Justin S. Smith

6:55 – 7:00 AM230. Defining the Role of Early SurgicalDecompression After Traumatic SpinalCord Injury: Results of a CanadianMulticenter StudyMichael G. Fehlings, Jefferson Wilson,Anoushka Singh, Catharine Craven, Henry Ahn, Brian Drew, Michael Ford

7:00 – 7:05 AM231. Age-Related Changes inNeurologically Intact Human Spinal CordsAssessed Using Diffusion Tensor MRImagingShekar N. Kurpad, Marjorie C. Wang,Michael Jirgis, Brian Schmit, John L. Ulmer,Brian Shender, Brian D. Stemper, Narayan Yoganandan, Allison Hyngstrom

YOUNGNEUROSURGEONS’

D I NNER6:30 PM

Wildflower A/B

Special Presentation by Dr. Robert F. Heary

All residents, fellows and youngneurosurgeons are welcome. PleaseRSVP to DePuy Spine, a Johnson &Johnson Company, Booth #505.



MEETING AGENDA34

7:05 – 7:10 AM232. A Combined NeuroprotectiveImmuno-modulatory Therapy MitigatesEarly Bladder Dysfunction AfterExperimental Spinal Cord InjuryDaniel J. Hoh, John H. Shin, Megan Clark,Christopher A. Iannotti, Ran Harel, Nico van Rooijen, Hai-Hong Jiang, Margot Damaser, Michael P. Steinmetz

7:10 – 7:15 AM233. The Role of Nitric Oxide in SecondarySpinal Cord Injury: Insights from a NewTransgenic ModelGeorge Al Shamy, Bettina Keller, Philippe Campeaux, Brendan Lee

7:15 – 7:20 AM234. The Impact of Weekend HospitalAdmission on the Timing of Interventionand Outcomes After Surgery for AcuteSpinal Cord Injury in the United States,2005-2008Hormuzdiyar H. Dasenbrock, Timothy F. Witham, Daniel M. Sciubba,Ziya L. Gokaslan, Ali Bydon


7:23 – 7:28 AM235. Long-term Outcomes of Patientswith Multilevel Ossification of thePosterior Longitudinal Ligament AfterLaminectomy, Laminoplasty andLaminectomy & Fusion: A Meta-Analysisof Observational StudiesHormuzdiyar H. Dasenbrock, Mohamad Bydon, Gayane Yenokyan,Timothy F. Witham, Ziya L. Gokaslan, Ali Bydon

7:28 – 7:33 AM236. Assessment of Potential Predictorsof Long Term Outcomes of Surgery forCervical Spondylotic Myelopathy: Clinical,Demographics and MR Imaging FactorsMichael G. Fehlings, Alina Karpova,Abhaya Vivek Kulkarni, Aileen Davis, Eric M. Massicotte

7:33 – 7:38 AM237. The AOSpine North America CervicalSpondylotic Myelopathy Study:Perioperative Complication RatesAssociated with Surgical Treatment Basedon a Prospective Multicenter Study of302 PatientsJustin S. Smith, Christopher I. Shaffrey,Branko Kopjar, Paul M. Arnold, Sangwook Yoon, Alexander R. Vaccaro,Darrel S. Brodke, Michael Janssen, Jens Chapman, Rick Sasso, Eric J. Woodard, Robert J. Banco, Eric M. Massicotte, Mark B. Dekutoski,Ziya L. Gokaslan, Christopher Bono,Michael G. Fehlings

7:38 – 7:43 AM238. Spinal Injuries in Children andAdolescentsJan Stulik, Jan Kryl, Michal Barna, Petr Nesnidal

7:43 – 7:48 AM239. Diffusion Tensor MR Imaging in Ratswith Varying Spinal Contusion SeverityShekar N. Kurpad, Brian Schmit, Michael Jirjis, Mohammed Ali Jazayeri,John L. Ulmer


7:52 – 7:57 AM240. CTA Screening for Vertebral ArteryInjury in Transverse Foramen Fractures in320 PatientsSanjay S. Dhall, Albert Jesse Schuette, Jack Barrow, Gerald E. Rodts, Jr., Daniel L. Barrow

7:57 – 8:02 AM241. Dens Fractures in Patients over 65Years of Age: Anterior Screw Fixation ofthe Dens Versus Posterior Fixation of C1-C2Jan Stulik, Jan Kryl, Petr Nesnidal

8:02 – 8:07 AM242. A Pilot Evaluation of the Role ofBracing in Stable Thoracolumbar BurstFracturesMohammed F. Shamji, Darren Roffey, Don Chow, Joseph O’Neil, Garth Johnson,Daryl Young, Eugene Wai

8:07 – 8:12 AM209. En Bloc Resection of CervicalChordomas: Series of 12 Patients andClinical OutcomesDaniel M. Sciubba, Camilo A. Molina,Ziya L. Gokaslan, Dean Chou,Jean-Paul Wolinsky, Timothy F. Witham,Ali Bydon, Christopher P. Ames


8:15 – 8:20 AMMeeting AnnouncementsModerators: Daryl R. Fourney, Praveen V. Mummaneni


David Cahill Memorial Controversies – Spine and Peripheral NervesModerators: Charles Kuntz, IV, Praveen V. MummaneniSession Description: This ScientificSession will involve a debatepresentation format. Controversialclinical management decisions will bepresented. Experts will argue theirperspectives with regard to themanagement scenarios for difficultspine and peripheral nerve cases. Learning Objectives: Uponcompletion of this course,participants should be able to:w Analyze the treatment options for synovial cysts.

w Distinguish risks and benefits of surgery vs. nonsurgical care for thoracolumbar burst fractures.

w Evaluate the role of fusion after lumbar discectomy.

w Identify the indications for surgery in degenerative scoliosis.

8:20 – 8:40 AMSynovial Cyst - Decompression vs.FusionFaculty: Robert F. Heary vs. Philip R. Weinstein

8:40 – 9:00 AMBurst Fracture IntactFaculty: Eric J. Woodard vs. James S. Harrop

9:00 – 9:20 AMRecurrent Lumbar Disc – Fuse or NotFaculty: Gerald E. Rodts, Jr. vs. R. John Hurlbert

9:20 – 9:40 AMDegenerative Scoliosis Presentingwith Radiculopathy - SimpleDecompression vs. Multilevel FusionFaculty: Iain H. Kalfas vs. Christopher I. Shaffrey



MEETING AGENDA 35



FELLOWSHIP AWARDS AND UPDATESAdam S. Kanter, Daniel M. Sciubba,Marjorie C. Wang

10:25 – 10:30 AMAward Presentations

SPINE CLINICAL TRIALS FELLOWSHIPPRESENTATIONS

10:30 – 10:42 AMMiminally Invasive vs. Open TLIF forSpondylolisthesisKhalid M. Abbed

10:42 – 10:54 AMCSM – Can Outcome Be Predicted byDiffusion Tensor Imaging?Marjorie C. Wang

10:54 – 11:05 AMA Web-based Registry for ComparativeEffectiveness Research for Back Pain inthe Wisconsin PopulationBasheal M. Agrawal


ORAL POSTER PRESENTATIONS IVModerators: Tanvir Choudhri, Paul Park

11:05 – 11:10 AM244. Determination of the MinimumImprovement in Pain, Disability, andHealth State Associated with Cost-Effectiveness: Introduction of the Conceptof Minimum Cost Effective Difference(MCED)Scott Parker, Owoicho Adogwa, Brandon J. Davis, Clint Devin, Matthew J. McGirt

11:10 – 11:15 AM245. Comparative Effectiveness ofMinimally Invasive vs. Open TransforaminalLumbar Interbody Fusion: Two-yearAssessment of Narcotic Use, Return toWork, Disability, and Quality of LifeOwoicho Adogwa, Scott Parker, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirt

11:15 – 11:20 AM246. Comparative Analysis of Surgical SiteInfection After Minimally Invasive vs.Open Posterior/Transforaminal LumbarInterbody Fusion: Analysis of HospitalBilling and Discharge Data from 5,328PatientsMatthew J. McGirt, Scott Parker, Jason Lerner, Luella Engelhart, Michael Y. Wang

11:20 – 11:25 AM247. Endoscopic Image-GuidedTranscervical Odontoidecomy: Long-TermOutcomes of 15 Patients with BasilarInvaginationHormuzdiyar H. Dasenbrock, Michelle J. Clarke, Ali Bydon, Daniel M. Sciubba, Timothy F. Witham,Ziya L. Gokaslan, Jean-Paul Wolinsky

11:25 – 11:30 AM248. Minimally Invasive Treatment ofAdjacent Segment Degeneration via XLIFJody A. Rodgers, W.B. Rodgers, Edward J. Gerber


11:35 – 11:40 AM249. Comparative Clinical OutcomesFollowing Minimally Invasive L5-S1Interbody Fusion, Comparison of TLIF,ALIF, and AxiaLif for Single-levelArthrodesisZachary Adam Smith, Larry T. Khoo

11:40 – 11:45 AM250. Cost-utility Analysis of MinimallyInvasive vs. Open MultilevelDecompression for Lumbar StenosisOwoicho Adogwa, Brandon J. Davis, Erin Fulchiero, Oran Aaronson, Joseph S. Cheng, Clint Devin, Matthew J. McGirt

11:45 – 11:50 AM251. Minimally Invasive Lateral AccessSurgery for Symptomatic Thoracic DiscHerniation: Initial Clinical Experience withClinical and Radiographic OutcomesGlen Pollock, Elias Dakwar, Mark Greenberg, Fernando L. Vale,William D. Smith, Juan S. Uribe

11:50 – 11:55 AM252. Early Radiographic Outcomes of XLIFin the Minimally Invasive Treatment ofAdult Scoliosis: Results from aProspective Multicenter Non-randomizedStudy of 107 PatientsFrank M. Phillips, Safdar Khan, Solas Degenerative Study Group

11:55 AM – 12:00 PM253. Economic Impact of MinimallyInvasive Spine Surgery Open vs. MISSpinal Fusion Costs in the PerioperativePeriod (First 45 Days)Jody A. Rodgers, W.B. Rodgers, John Lucio,Brent Vanconia, Kevin J. DeLuzio


12:05 – 12:10 PM254. Perioperative Outcomes andComplications Following XLIF for theTreatment of Adult Scoliosis: Results of aProspective, Non-randomized, MulticenterEvaluationRobert E. Isaacs, Jonathan Hyde, J. Allan Goodrich, W.B. Rodgers, Frank M. Phillips, Solas Degenerative Study Group

12:10 – 12:15 PM255. Correlation of PreoperativeDepression and Somatic PerceptionScales with Postoperative Disability andQuality of Life After Lumbar DiscectomyScott Parker, Kaisorn L. Chaichana,Owoicho Adogwa, Joseph S. Cheng,Matthew J. McGirt

12:15 – 12:20 PM256. Microdiscectomy Improves Pain-associated Depression, Somatic Anxiety,and Mental Well-being in Patients withHerniated Lumbar DiscScott Parker, Richard L. Lebow, Owoicho Adogwa, Adam S. Reig, Joseph S. Cheng, Matthew J. McGirt

12:20 – 12:25 PM257. Management of Degenerative LumbarStenosis Related to Meyerding Grade ISpondylolisthesis: The Reappraisal ofUnilateral LaminotomyMario Ganau, Enrico De Micheli, Massimo Gerosa

12:25 – 12:30 PM258. Determination of Minimum ClinicallyImportant Difference (MCID) in Pain,Disability, and Health State Utility AfterTransforaminal Lumbar Interbody Fusion(TLIF) for Degenerative LumbarSpondylolithesisScott Parker, Owoicho Adogwa, Alexandra Paul, Bill Anderson, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirt




EXHIBITOR INFORMATION36

EXHIBIT HALL – GRAND CANYON BALLROOM The Exhibit Hall, located in the Grand Canyon Ballroom, will feature:More than 60 exhibiting companiesdisplaying state–of–the–art equipment,products and services.

Lunch in the Exhibit Hall*:Plan to spend yourThursday lunch break mingling with exhibitors betweenWhat’s New presentations.

Reception with the Exhibitors: Join us Thursdayevening for another great networking opportunity! Takethe time to browse the aisles of the Exhibit Hall and visitwith your corporate colleagues while enjoying cocktailsand hors d’oeuvres.

E–mail Café: Stay in touch with home and the officethrough this complimentary attendee service.

Digital Posters:Browse over 240 abstracts enhanced byphotos and video. The digital format also makes it easyto search for abstracts by author or topic.

What’s New Sessions: Join the crowd during dailybreaks and Thursday lunch as speakers share the latestin cutting-edge research and technology. *Lunch in the Exhibit Hall is complimentary to all medical

attendees and guests ages 18 and older.

Exhibit Hall HoursThursday, March 109:00 AM – 7:00 PM

Friday, March 119:00 AM – 12:00 Noon

Saturday, March 129:00 AM – 12:00 Noon

Beverage Break andWhat’s New Sessions Thursday, March 109:30 – 10:15 AM12:30 – 1:25 PM*3:00 – 3:45 PM

Friday, March 119:30 – 10:15 AM

Saturday, March 129:40 – 10:25 AM

Advanced Biologics 713 555 Corporate Parkway, Suite 260 Ladera Ranch, CA 92694 800-272-0267 www.advancedbiologicscorp.com

Aesculap Implant Systems 501 3773 Corporate Parkway Center Valley, PA 18034 610-797-9300 www.aesculapusa.com

Alphatec Spine 213 5818 El Camino Real Carlsbad, CA 92008 760-994-3793 www.alphatecspine.com

Amedica/US Spine 208 1885 West 2100 South Salt Lake City, UT 84119 801-839-3500 www.amedicacorp.com

Anulex Technologies, Inc. 417 5600 Rowland Road, Suite 280 Minnetonka, MN 55343 952-224-4000 www.anulex.com

Aspen Medical Products, Inc. 702 6481 Oak Canyon Irvine, CA 92618-5202 949-681-0200 www.aspenmp.com

ASSI-Accurate Surgical 104 300 Shames Drive Westbury, NY 11590 800-645-3569 www.accuratesurgical.com

Bacterin International, Inc. 204600 Cruiser LaneBelgrade, MT 59714406-388-0480www.bacterin.com

Baxano, Inc. 718655 River Oaks ParkwaySan Jose, CA 95134408-514-2200www.BAXANO.com

Baxter 618 One Baxter Parkway Deerfield, IL 60015 800-423-2090 www.advancingbiosurgery.com

*Biomet Spine 301 100 Interpace Parkway Parsippany , NJ 07054 973-299-9300 www.biometspine.com

Buxton BioMedical, Inc. 109 15A Melanie Lane East Hanover, NJ 07936 973-560-4848 www.buxtonbio.com



EXHIBITOR INFORMATION 37

Captiva Spine 516 967 Alternate A1A, Suite #1 Jupiter, FL 33477 877-772-5571 www.captivaspine.com

Carl Zeiss Meditec, Inc. 113 5160 Hacienda Drive Dublin, CA 94568-7562 925-557-4100 www.meditec.zeiss.com

Centinel Spine, Inc. 212 505 Park Avenue, 14th Floor New York, NY 10022 212-674-3337 www.centinelspine.com

ChoiceSpine 105 314 Erin Drive, Suite 102 Knoxville, TN 37919 865-246-3333 www.choicespine.net

Congress of Neurological Surgeons 704 10 N. Martingale Road, Suite 190 Schaumburg, IL 60173-2294 847-240-2500 www.cns.org

Covidien 706 555 Long Wharf Drive New Haven, CT 06511 203-821-4500 www.covidien.com

Custom Spine, Inc. 201 1140 Parsippany Boulevard Parsippany, NJ 07054 973-808-0019 www.customspine.com

*DePuy Spine, a Johnson & Johnson Company 505 325 Paramount Drive Raynham, MA 02767 508-880-8100 www.depuyspine.com

Elliquence, LLC 413 2455 Grand Avenue Baldwin, NY 11510 516-277-9000 www.elliquence.com

Elsevier/Saunders/Mosby 700 1600 JFK Boulevard, Suite 1800 Philadelphia, PA 19103 215-239-3490 www.elsevierhealth.com

Gauthier Biomedical, Inc. 209 1235 North Dakota Drive, Suite G Grafton, WI 53024 262-546-0010 www.gauthierbiomedical.com

Globus Medical 513 2560 General Armistead Avenue Audubon, PA 19403 610-930-1800 www.globusmedical.com

Holmed Corporation 111 40 Norfolk Avenue South Easton, MA 02375 508-238-3351 www.holmed.net

Integra Spine 512 311 Enterprise Drive Plainsboro, NJ 08536 609-275-0500 www.integra-ls.com

*K2M, Inc. 601 751 Miller Drive, SE Leesburg, VA 20175 703-777-3155 www.k2m.com

Karl Storz Endoscopy-America, Inc. 203 2151 East Grand Avenue El Segundo, CA 90245 800-421-0837 www.karlstorz.com

LANX Inc. 619390 Interlocken Crescent, Suite 890Broomfield, CO 80021303-443-7500www.lanx.com

LDR 715 4030 W. Braker Lane, Suite 360 Austin, TX 78759 512-344-3300 www.ldrspine.com

Life Instrument Corporation 219 91 French Avenue Braintree, MA 02184 800-925-2995 www.lifeinstruments.com

Lippincott Williams and Wilkins - WKH 714Two Commerce Square, 2001 Market Street Philadelphia, PA 19103 215-521-8300 www.wolterskluwer.com

*Medtronic 305 2600 Sofamor Danek Drive Memphis, TN 38132-1719 800-876-3133 www.medtronic.com

New World Rarities 304 670 Old Willets Path Hauppauge, NY 11788 800-431-1018 www.newworldrarities.com

NovaBone Products, LLC 416 1551 Atlantic Boulevard #105 Jacksonville, FL 32207 386-462-7660 www.novabone.com

Nutech Medical, Inc. 112 2641 Rocky Ridge Lane Birmingham, AL 35216 205-290-2158 www.nutechmedical.com

*NuVasive 613 7475 Lusk Boulevard San Diego, CA 92121 800-475-9131 www.nuvasive.com

Orthofix, Inc. 200 3451 Plano Parkway Lewisville, TX 75056 800-527-0404 www.orthofix.com

Orthovita, Inc. 102 77 Great Valley Parkway Malvern, PA 19355 800-676-8482 www.orthovita.com



EXHIBITOR INFORMATION38

Paradigm Spine 709 505 Park Avenue, 14th Floor New York, NY 10022 212-583-9700 www.paradigm-spine.de

Pioneer Surgical 318 9600 Great Hills Trail, Suite 160E Austin, TX 78759 512-372-4312 www.pioneersurgical.com

PMT® Corporation 712 1500 Park Road Chanhassen, MN 55317-8200 800-626-5463 www.pmtcorp.com

Richard Wolf Medical Instrument Corporation 605 353 Corporate Woods Parkway Vernon Hills, IL 60061-3110 847-913-1113 x 607 www.richardwolfusa.com

Rose Micro Solutions LLC 110 4105 Seneca Street West Seneca, NY 14224 716-608-0009 www.rosemicrosolutions.com

RosmanSearch, Inc. 103 30799 Pinetree Road #250 Pepper Pike, OH 44124 216-287-2302 www.rosmansearch.com

Signus Medical, LLC 317 18888 Lake Drive East Chanhassen, MN 55317 952-294-8700 www.signusmedical.com

Spinal Elements, Inc. 100 2744 Loker Avenue West, Suite 100 Carlsbad, CA 92010 760-607-0121 www.spinalelements.com

Spine Wave 306 Three Enterprise Drive, Suite 210 Shelton, CT 06484 203-944-9494 www.spinewave.com

SpineGuard 108 301 Howard Street, Suite 970 San Francisco, CA 94105 415-512-2500 www.spineguard.com

Spineology, Inc. 313 7800 3rd Street North, Suite 600 St. Paul, MN 55128 651-256-8500 www.spineology.com

SpineSearch LLC 415 PO BOX 184 Carle Place, NY 11514 800.733.1109 www.spine-search.com

SpineSelect, LLC 205 408 Council Circle Tupelo, MS 38801 877-774-6395 www.spineselect.com

SpineView, Inc. 701 48810 Kato Road, Suite 100E Fremont, CA 94538 510-623-1931 www.spineview.com

*Stryker 300 2 Pearl Court Allendale, NJ 07401 866-987-7463 www.stryker.com

*Synthes Spine 101 1302 Wrights Lane East West Chester, PA 19380 610-719-5000 www.synthes.com

TeDan Surgical Innovations 412 11333 Chimney Rock Road, Suite 180 Houston, TX 77035 713-726-0886 www.tedansurgical.com

Thompson Surgical Instruments 707 10170 East Cherry Bend Road Traverse City, MI 49684-6843 231-922-5178 www.thompsonsurgical.com

TranS1, Inc. 607 301 Government Center Drive Wilmington, NC 28403 910-332-1700 www.trans1.com

Vertebral Technologies, Inc. 207 5909 Baker Road, Suite 550 Minnetonka, MN 55345 952-912-5400 www.vti-spine.com

X-Spine Systems, Inc. 519452 Alexandersville RoadMiamisburg, OH 45342937-847-8400www.xspine.com

Zimmer Spine 401 7375 Bush Lake Road Edina, MN 55439-2027 952-832-5600 www.zimmerspine.com

*Indicates a 2011 Corporate Supporter



EXHIBITOR INFORMATION 39

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100In Situ Placement of High-dose rhBMP-2within Spine Tumors Slows Tumor Growthand Decreases Onset to Paralysis in a RatModel of Metastatic Breast CancerCamilo A. Molina, Rachel Sarabia-Estrada,Guergana Panayotova, Antonio Aguilera,Ziya L. Gokaslan, Jean-Paul Wolinksy, Ali Bydon, Daniel M. Sciubba Introduction: Recombinant human bonemorphogenic proteins (rhBMPs) areFDA-approved for specific spinal fusionprocedures, but use is contraindicated inspine tumor resection beds due tounclear interaction between tumor tissueand such growth factors. Interestingly, anumber of studies suggest that BMPsmay slow growth of adenocarcinomas invitro, and adenocarcinomas represent themajority of histopathologies found inbony spine tumors. In this study, wehypothesized that high concentrationrhBMP-2 placed in an intraosseous spinetumor rat model could show tumorsuppression and prolong onset toparalysis in such animals.Methods: 21 female nude athymic ratswere randomized into three groups.Group 1 (n=7) underwent transperitonealexposure and implantation of breastadenocarcinoma (CRL-1666) into the L6lumbar spine segment, followed byimplantation of 15 micrograms ofrhBMP-2. Group 2 (n=7) underwentexposure and tumor implantation on thelumbar spine, but no local treatment withrhBMP-2. Group 3 (n=7) solelyunderwent exposure of the lumbar spine.The Basso-Beattie-Bresnahan (BBB) scalewas used to monitor daily motor functionregression and time to paresis(BBBscore< 7).Results:No animals in Group 1 wereparetic by day 15 (median BBB score of20, p=<0.0027). All animals in Group 2were paretic by day 15 (median BBB scoreof 0, p=0.0024) with a mean time toparesis (±SD) of 13.5±1.4 days. Time toparesis was significantly differentbetween Group 1 and Group 2 (p<0.001).

Group 3 (control) exhibited noneurological motor deficit. Gross andmicroscopic tumor volume was alsosignificantly (p<0.048) different betweenGroups 1 and 2.Conclusion:This study shows that high-dose administration of local rhBMP-2 in arat spine tumor model of breast cancernot only fails to stimulate local tumorgrowth, but also decreases local tumorgrowth and onset of paresis in animals.This is the first preclinical experimentshowing that local placement of rhBMP-2in a spine tumor bed may slow tumorprogression and delay associatedneurological decline.

101The Effect of Surgery on Health RelatedQuality of Life and Functional Outcome inPatients with Metastatic Epidural SpinalCord Compression: Initial Results of theAOSpine North America ProspectiveMulticenter StudyMichael G. Fehlings, Branko Kopjar,Alexander R. Vaccaro, Paul M. Arnold,Charles Fisher, Ziya L. Gokaslan, James M. Schuster, Mark B. Dekutoski, Joel Finkelstein, Laurence D. Rhines Introduction:Metastatic epidural spinalcord compression (MESCC) is commonand recent studies have providedevidence that in selected patientscombined surgery and radiotherapyprovides the optimal neurologicalrecovery. However, patients with MESCChave relatively short life-expectancy andface numerous challenges. Hence, theimpact of surgery on improving quality oflife outcomes in the setting of MESCC isless clear.Methods: 72 surgical patients wereenrolled in a prospective multicenter,cohort study involving 8 sites in NorthAmerica. Outcomes were assessed usingthe pain assessments, ASIA scale, SF-36v2, and EQ-5D.Results: Average age was 58 years (SD 11),65% were males. Common primary siteswere lungs (32%), prostate (15%), breast(11%), and kidney (11%). The baselineEQ5D was .38; SF36PCS 32; SF36MCS 39,VAS Pain 6.1; ASIA Impairment grade atbaseline was 35% (E), 45% (D), 14% (C),3% (B) and 3% (A). Median survival was157 days; 93% survived one month; 62%survived 3 months, 41% survived 9months, 32% survived 12 months. Amongthe surviving patients, the averageimprovement at 3 months was for .23 forEQ5D (P< .001), 26 for ODI (P < .001) , 2.6for VAS Pain (P < .05). Also, there was asignificant improvement in ASIAImpairment grade (P < .05). There was no

significant change in SF36 PCS and MCS.The gains in EQ5D, ODI and VAS Painwere maintained in patients whosurvived 6 months.Conclusion: Surgically treated patientswith MESCC have poor survival. Amongthe surviving patients, the surgicaltreatment is associated withimprovement in symptoms andfunctional outcomes. However, this doesnot translate into significant gains inoverall health related quality of life.Individuals with less than three monthlife expectancy may be less than idealcandidates for surgical intervention.Further follow-up and a larger samplesize in this ongoing study will help toidentify subgroups of patients who maybenefit from the surgical intervention.

102Survival of Patients with MalignantPrimary Osseous Spinal Neoplasms fromthe Surveillance, Epidemiology, and EndResults (SEER) Database from 1973-2005Kaisorn L. Chaichana, Scott Parker,Owoicho Adogwa, Debraj Mukherjee,Oran Aaronson, Joseph S. Cheng, Ziya L. Gokaslan, Matthew J. McGirt Introduction:Malignant primary osseousspinal neoplasms are aggressive tumorswhich remain associated with pooroutcomes. To date, prognosis is basedupon small single center series. In orderto assess national trends in histology-specific survival, we reviewed survivaldata spanning 30 years from thesurveillance, epidemiology, and endresults (SEER) registry.Methods:The SEER registry (1973-2003)was queried to identify primary spinalchordoma, chondrosarcoma,osteosarcoma, or Ewing’s sarcoma viaICD-O-2 coding. Survival was assessedvia Cox proportional-hazards regressionanalysis.Results: 1,892 patients were identifiedwith primary osseous spinal neoplasms(414 chordoma, 579 chondrosarcoma,430 osteosarcoma, 469 Ewing’s sarcoma).Chordomas presented in older (59±17,p<0.01) and Ewing’s Sarcoma in younger(19±11, p<0.01) patients vs. other tumors.The incidence of each tumor typeremained similar per decade. African-Americans comprised a significantlygreater proportion of osteosarcoma thanother tumors (9.6 vs. 3.5%, p<0.01).Mobile spine vs. sacrum was more oftenlocation for chordomas than othertumors (47% vs. 23%, p<0.05).Osteosarcoma and Ewing’s Sarcoma were3-fold more likely to present withmetastasis (31% vs. 8%). Surgical

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ORAL PLATFORM ABSTRACTS 41

resection was performed more frequentlyfor chordoma (88%) andchondrosarcoma (88%) thanosteosarcoma (61%) and Ewing’s (53%).Median survival was histology specific(Osteosarcoma: 11mo, Ewing’s: 26mo,chondrosarcoma: 37mo; chordoma:50mo) Survival was worse in patients withmetastasis at presentation, Figure 1, butunaffected by site (mobile spine vs.sacrum/pelvis) Figure 2. More recent yearof diagnosis was associated with greaterutilization of surgery (OR1.23, p<0.001)and improved survival for isolated spinalEwing’s sarcoma (HR, 0.95, p=0.001),chondrosarcoma (HR, 0.98, p=0.009), andchordoma (HR, 0.98, p=0.10) but was notassociated with increased utlization ofsurgery (OR, 1.01, p=0.43) or survival forosteosarcoma, Figure 3.Conclusion: In our analysis of a 30-yearU.S. population based cancer registry(SEER), we provide nationallyrepresentative prognosis and survivaldata for malignant primary spinalosseous neoplasm. Use of surgery andoverall survival has improved for isolatedspine tumors with advancements in careover the past four decades. These resultsmay be helpful in providing historicalcontrols for understanding the efficacy ofnew treatment paradigms patienteducation and guiding level ofaggressiveness in treatment strategies.

103Electrical Stimulation Enhances Axon andNerve RegenerationRajiv Midha, Bhagat Singh, Qing Gui Xu,Colin Franz, Colin Dalton, Tessa Gordon,Doug ZochodneIntroduction: Axon regeneration afterperipheral nerve injury is delayed andincomplete. Brief low frequency electricalstimulation (ES) applied immediatelyafter injury is known to improve axonalregeneration. With these findings, weaimed to explore several new features ofthis interesting property.Methods:We examined early axon andSchwann cell (SC) outgrowth beyondtransection sciatic nerve injuries in micecomparing sham ES to brief ES (3V, 20Hz,and pulse width 0.1 ms for 1 hr) deliveredonly at the time of injury. In a secondapproach to examine early axonoutgrowth, an identical protocol wasexamined using harvested adult ratsensory neurons in vitro stimulated overa novel microelectrode array construct.Results:We identified acceleratedoutgrowth beyond the repair site of bothaxons and SCs following ES. These earlybenefits translated into an ongoing

impact of ES on regeneration. There wasenhanced myelinated axon repopulationby 21 days across transection sites, withhigher numbers of retrogradely labelledmotor neurons regenerating their axons.In thy-1 GFP mice with fluorescentperipheral axons, we confirmed the earlyimpact on outgrowth and identifiedearlier arrival of GFP cutaneous axons inperipheral sensory targets. This wasstrongly correlated with more rapidrecovery of mechanical and thermalsensation in the foot and of compoundmuscle action potentials beyond theinjury site. The in vitro paradigmidentified robust immediate rises inneurite initiation of the stimulatedneurons and improved outgrowth ascompared to control conditions.Conclusion: These data support therobust role of brief ES followingperipheral nerve trunk injuries inpromoting axon initiation and outgrowthafter transection, in axon maturation andin repopulation of targets. This is a widerrepertoire of impact than previouslyknown and its replication in vitrosupports the hypothesis that a neuronspecific reprogrammed injury response isrecruited by the ES protocol.

104Efficacy and Active Ingredients in anEpidural Analgesic Paste after LumbarDecompression: A ProspectiveRandomized Double-Blind Controlled TrialRoberto Jose Diaz, S. Terence Myles, R. John Hurlbert Introduction: The purpose of this studywas to evaluate the efficacy and activecomponents of a previously describedepidural analgesic paste in controllingpostoperative pain and facilitating earlydischarge from hospital after lumbardecompressive surgery.Methods: A prospective randomizeddouble-blind controlled trial wasconducted. Two-hundred and onepatients were randomized to one of fouranalgesic epidural pastes at the time oflumbar spinal surgery: combo paste(morphine + methylprednisolone),steroid paste (methylprednisolone alone),morphine paste (morphine alone), andplacebo. The primary outcome measuresused were narcotic and non-narcotic useand McGill Pain Questionnaire (MPQ).Secondary outcome measures were:modified ASIA score, SF-36, time toambulation and discharge from hospital.Results: Administration of combo andsteroid paste, but not morphine pasteresulted in a statistically significantreduction in mean PRI and PPI

components of the MPQ in the first 3days after surgery. Narcotic analgesicconsumption was reduced onpostoperative day 1 in the combo pasteand steroid paste groups. No difference intime to ambulation or discharge, generalhealth perception, ABPI scores, orneurological recovery was observed.Conclusion:We have demonstrated theefficacy of epidural analgesic pastecontaining methylprednisolone acetateto produce a robust postoperativeanalgesic effect. This paste should beconsidered for use in patients undergoingroutine lumbar decompressive surgery.

105Radiographic Same-level Recurrent DiscHerniation After Lumbar Discectomy:Prospective Longitudinal Study with Two-year Follow-upScott Parker, Richard L. Lebow, Owoicho Adogwa, Scott Parker, Adrija Sharma, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirt Introduction: To date, the incidence ofradiographic same-level recurrent discherniation has not been studiedprospectively with sequential imaging.Furthermore, the clinical relevance ofradiographic recurrent disc herniation onMRI after discectomy remains unknown,particularly in patients withoutsymptoms or with poorly localized painafter surgery. We previously reportedfactors associated with symptomaticsame-level recurrent disc herniation fromthis cohort. In a post-hoc analysis, we setout to determine the incidence ofasymptomatic same-level recurrent discherniation and assess their effect on two-year outcome.Methods: One hundred and eightpatients undergoing lumbar discectomyfor a single-level herniated disc at fiveinstitutions were prospectively followedfor two years. CT and MRI of the lumbarspine were obtained every three monthsto assess re-herniation and disc heightloss. Leg and back pain visual analoguescale (VAS), Oswestry Disability Index(ODI), and quality of life (SF-36 physicalcomponent) were assessed 3, 6, 12, and24 months after surgery.Results: No patients demonstratedresidual disc on postoperative MRI. Bytwo years after discectomy, 25 (23.1%)patients had demonstrated radiographicevidence of recurrent disc herniation atthe level of prior discectomy (mean 11.8 ±8.3 months after surgery), the majority ofwhich were asymptomatic [14 (13%)]patients. The occurrence ofasymptomatic re-herniation was not




associated with disc height loss or anyoutcome measure (VAS, ODI, SF-36) bytwo years.Conclusion: In a prospective cohort studywith serial imaging, nearly one-fourth ofpatients undergoing lumbar discectomydemonstrated radiographic abnormalitysuggestive of recurrent disc herniation atthe level of prior surgery, the majority ofwhich were asymptomatic.Asymptomatic disc herniation was notassociated with clinical consequences bytwo years. Clinically silent recurrent discherniation is not uncommon afterlumbar discectomy. When obtaining MRIevaluation within the first two years ofdiscectomy, providers should expect thatradiographic evidence of re-herniationmay be encountered and that treatmentshould only be considered whencorrelating radicular symptoms exist.

106Cost Effectiveness of MultilevelHemilaminectomy for Lumbar StenosisAssociated RadiculopathyErin Fulchiero, Brandon J. Davis, Owoicho Adogwa, Oran Aaronson, Joseph S. Cheng, Clint Devin, Matthew J. McGirt Introduction: Laminectomy for lumbarstenosis associated radiculopathy isassociated with improvement in pain,disability, and quality of life. However,given rising healthcare costs, attentionhas been turned to question the cost-effectiveness of lumbar decompressiveprocedures. The cost-effectiveness ofmultilevel hemi-laminectomy forradiculopathy remains unclear. We setout to assess the comprehensive medicaland societal costs of multi-levellaminectomy at our institution anddetermine its cost-effectiveness in thetreatment of degenerative lumbarstenosis.Methods: Fifty-four consecutive patientsundergoing multilevel hemi-laminectomy for lumbar stenosisassociated radiculopathy after 6 monthsof conservative therapy were included.Over a two-year period, total back-relatedmedical resource utilization, missedwork, and improvement in pain (VAS-LP),disability (Oswestry Disability Index(ODI)), quality of life (SF-12), and health-state values [quality adjusted life years(QALYs), calculated from EQ-5D with U.S.valuation] were assessed. Two-yearresource use was multiplied by unit costsbased on Medicare national allowablepayment amounts (direct cost) andpatient and care-giver work-day losseswere multiplied by the self-reported

gross-of-tax wage rate (indirect cost).Mean total two-year cost per QALYgained after TLIF was assessed.Results: Compared to preoperative healthstates reported after at least 6 months ofmedical management, a significantimprovement in VAS-BP, ODI, and SF-12(physical and mental components) wasobserved two years after laminectomy,with a mean two-year gain of 0.72 QALYs ,Figure 1. Mean ±SD total two-year cost ofmultilevel hemilaminectomy was $23,477±9,912 (Surgery cost: $10,220 ±100;Outpatient resource utilization cost:$2,805 ±1,958; Indirect cost: $10,452±9,364). Multilevel hemilaminectomy wasassociated with a mean two-year cost perQALY gained of $32,606.Conclusion: Multilevel hemilaminectomyimproved pain, disability, and quality oflife in patients with lumbar stenosis-associated radiculoapthy. Total cost perQALY gained with multi-levellaminectomy was $32,606 whenevaluated two years after surgery withMedicare fees, suggesting that multilevelhemilaminectomy is a cost effectivetreatment of lumbar radiculopathy.

107Provocative Discography ScreeningImproves Surgical OutcomePetra Margetic, Marin F. Stancic Introduction: The objective of the studywas comparison of surgical outcomes ofpatients operated on withoutdiscography and patients that underwentdiscography.Methods: Study was designed as arandomized controlled trial. According topower analysis study comprised 310patients divided in the experimental(No=207) and the control (No=103)group. Inclusion criteria were low backpain resistant to the nonsurgicaltreatment for more than 6 months andconventional radiological findingsshowing degenerative changes withoutclear generator of the pain. Exclusioncriteria were red flags. Before discographypatients filled in Oswestry DisabilityIndex (ODI), SFPF36, Zung and MSPGQQuestioners. At 1-year follow-upexamination patients filled in ODI,SFPF36, Likert scale which analyzingsatisfaction with procedure and answerto the question would he/she repeatdiscography if it would be necessary.Results:With independent t-test groupwithout discography preoperative hadODI P 0.002 between patients with DDDand other generator of the pain while thepostoperative had P 0.433. PreoperativeSFPF had P 0.001 but postoperative P

were 0.360. VAS preoperative had P 0.953and postoperative 0.003. In a group withdiscography ODI and SFPF preoperativeand postoperative had P<0.001. VASpreoperative had P 0.306 andpostoperative <0.001. With dependent t-test in both groups with/withoutdiscography ODI, SFPF and VASpreoperative and postoperative had P<0.001.Conclusion: DDD treated surgicallywithout discography didn’t reachclinically significant improvement of 15ODI points as recommended by FDA forthe patients treated with fusion.Provocative discography screening withpsychological testing in the trial groupmade improvement following fusionclinically significant. For otherdegenerative generators of the paindiscography didn’t prove usefuldiagnostic tool. As there were no postdiscography spondilodiscitis and patientsare willing to repeat procedure if it wouldbe necessary, our results suggestdiscography use in preoperative workoutof patients with DDD.

108The Impact of Surgeon Professional Feesto the National Cost of HealthcareCamilo A. Molina, Ziya L. Gokaslan,Timothy F.Witham, Ali Bydon, Jean-Paul Wolinsky, Daniel M. Sciubba Introduction:With the increasedattention given to the large amount ofnational funds supporting health care inthe United States, there have beensignificant changes in the reimbursementsystem for surgical procedures by thefederal government. In efforts to decreaseoverall spending, individual surgeonshave seen yearly reimbursement cuts. Inthis study, we reviewed the charges andreimbursements at a major academicinstitution for lumbar laminectomy andcompared the amounts reimbursed to thehospital and to the surgeon.Methods: The reimbursement scheduleof an academic spine surgeon wascollected over twelve months for lumbarlaminectomy procedures. Bills andcollections by the hospital andprofessional fees of the surgeon wereobtained for comparative analysis.Results: During a twelve-month period,patients underwent a lumbarlaminectomy involving on average 3levels and stayed in the hospital onaverage 2.3 days. Complications wereuncommon (13%). Average professional-fee billing for the surgeon was $8,200.00and collection was $1,647.79 (24% forprivate and 18% for Medicare/Medicaid




insurance). Average hospital billing forthe inpatient hospital stay minusprofessional fees from the surgeon was$19,348 and average collection on suchbills was $17,758 (92% for Private and89% for Medicare/Medicaid insurance).Percentage of total costs for suchprocedures that was allocated to surgeonreimbursement was 12% for private and7% for Medicare/Medicaid insurance.Conclusion:Current strategies forcontaining rising health care costsinclude decreasing physicianreimbursement; unfortunately, overallhealth care costs continue to rise. Basedon this analysis, the proportion of overallcosts allocated to professional fees forsurgical procedures is small, while thoseallocated to hospital costs, whichincludes hospital stay, drugs, implants,imaging, and rehabilitation, etc., are fargreater. Findings suggest that the currentfocus on decreasing physicianreimbursement as the principal costsaving strategy will lead to minimalreimbursement for surgeons withoutsubstantial drop in the overall cost ofnational healthcare.

109Effect of Patient Pain Expectations andPreoperative SF-36 Mental ComponentSummary Scores on Clinical OutcomesFollowing Anterior Cervical Discectomyand FusionFrances A. Carr, Theresa Hernandez, Kyle M. Healy, Ewell Lee Nelson, Alexander Mason, Sigita Burneikiene, Alan T. Villavicencio Introduction:The primary purpose ofthis study was to analyze if preoperativepatient expectations and SF-36 MCSscores have any effect on clinicaloutcomes.Methods: A prospective clinical study wasperformed. This study included 79 (38males, 41 females) patients whounderwent one- to three-level ACDFsurgery. Preoperatively, patients wereasked to rate their expected pain aftersurgery and complete VAS neck/arm (0-10), NDI and SF-36 PCS/MCS scales.Patients were divided into two groups forthe expectation analyses: completeresolution of pain (n=44) and some painexpected (n=35) postoperatively. Theabove clinical parameters and patientsatisfaction with results scores weremeasured postoperatively. The meanfollow up was 38.8 months (range, 7-59).Results:Overall, all postoperativemeasures depicted significantimprovement (Table 1). Patientdemographics and clinical parameters

were comparable preoperatively betweenthe expectation groups (Table 2, 3).Controlling for respective preoperativescores, patients who expected no painreported lower postoperative neck/armpain (p<0.02), higher SF-36 MCS (p=0.04)and higher satisfaction with results(p=0.007) scores, although no significantdifferences were detected in postoperativeNDI or SF-36 PCS scores compared withpatients that expected some pain.Furthermore, controlling for respectivepreoperative scores, higher preoperativeSF-36 MCS scores significantly predictedlower postoperative neck pain (p=0.003)and NDI (p=0.004) scores, and higherpostoperative SF-36 PCS (p=0.002), SF-36MCS (p=0.001) and satisfaction (p=0.03)scores.Conclusion: Patients who expected nopain postoperatively reported betterpostoperative scores on the moresubjective outcome measures (VAS armand neck, satisfaction with results), aswell as the SF-36 mental componentscore. Patients with higher preoperativemental component scores had betterclinical outcomes (VAS neck, NDI, SF-36PCS/MCS, satisfaction with results). Theresults suggest that optimism in patients’expectations as well as other potentialpsychological factors predict improvedclinical outcomes and patientsatisfaction.

110Factors Associated with the Occurrenceof Perioperative Complications in theTreatment of Cervical SpondyloticMyelopathy Based on 302 Patients fromthe AOSpine North America CervicalSpondylotic Myelopathy StudyJustin S. Smith, Christopher I. Shaffrey,Branko Kopjar, Paul M. Arnold, Sangwook Yoon, Alexander R. Vaccaro,Darrel S. Brodke, Michael Janssen, Jens Chapman, Rick Sasso, Eric J. Woodard,Robert J. Banco, Eric M. Massicotte, Mark Dekutowski, Ziya L. Gokaslan,Christopher Bono, Michael G. Fehlings Introduction: Surgery is often warrantedfor cervical spondylotic myelopathy(CSM). Our objective was to assess forclinical and surgical factors associatedwith the occurrence of complications inthe surgical treatment of CSM based on aprospective multicenter study.Methods:The AOSpine North AmericaCSM study is a recently completedprospective multicenter study of patientssurgically treated for CSM. Rates ofperioperative complications (within 30days of surgery) were assessed andstratified based on clinical and surgical

factors.Results: 302 patients were enrolled (meanage: 57 years, range: 29-86). Of 332reported adverse events, 73 wereadjudicated to be complications,including 25 major (8%) and 48 minor(16%). Of patients treated with anterior-only (n=176), posterior-only (n=107), andcombined anterior-posterior procedures(n=19), 11%, 19%, and 37%, respectively,had one or more complications(p=0.008). Procedures including aposterior approach had a significantlyhigher rate of infection (6.3% vs 0.6%,p=0.005). Dysphagia was significantlymore common with anterior-only (2.3%)or combined anterior-posterior (21.1%)procedures, compared with posterior-only procedures (0.9%, p<0.001). C5radiculopathy/palsy was not significantlyassociated with surgical approach(p=0.8). Occurrence of complications wassignificantly associated with increasedoperative time (p<0.001), increased bloodloss (p<0.001), and inclusion of a fusion(p=0.01), but not with age (p=0.9), body-mass index (BMI, p=0.7), smoking(p=0.3), prior surgery (p=0.09), or numberof operated vertebrae (p=0.9).Conclusion: For the surgical treatment ofCSM, operative factors, including surgicalapproach, operative time and blood loss,have stronger associations with theoccurrence of perioperativecomplications than do patient factors,such as age, BMI, and smoking.

111Comparative Economic Analysis of Ventralvs. Dorsal Surgery for CervicalSpondylotic MyelopathyAndrew Becker, Robert Gray Whitmore,Susan Christopher, Jill Curran, Benjamin Baskin, Zoher Ghogawala Introduction:The objective of this studywas to determine the optimal surgicalapproach (ventral vs. dorsal) for patientswith 3-4 levels of stenosis resulting incervical spondylotic myelopathy (CSM).Methods: A prospective, non-randomized, 8-center trial wasconducted. Patients aged 40-79 yearswith 3-4 levels of degenerative cervicalspondylosis resulting in CSM wereenrolled. Four outcome assessments (SF-36, Oswestry Neck Disability Index (NDI),mJOA, EuroQol-5D) were obtainedpreoperatively and postoperatively at 6months and 1 year. A hospital-basedeconomic analysis used costs derivedfrom total hospital charges and year-specific cost-to-charge ratios.Results:This study enrolled fifty-sixpatients (mean age – 62 years; gender –




57% male). Ventral decompression andfusion (VF) was performed on twenty-fivepatients, dorsal laminectomy with fusion(DF) on twenty-four, and dorsallaminectomy without fusion (L) on nine.One-year follow-up data was available on73% of the cohort. Baseline demographicsand outcome assessments werecomparable at baseline. DF patients hadsignificantly longer lengths of stay thanVF (4.4 days vs. 3.1 days, P=0.03). VFpatients showed significant 1-yearimprovements for each of the fouroutcome measures and DF patientsshowed significant improvement in themJOA. VF patients showed larger 1-yearimprovements than DF in 3 of the 4assessments (Figure 1). Thirteen VF,seventeen DF, and five L patients wereincluded in the cost analysis (Figure 2). VFwas clearly cost-effective when comparedto DF.Conclusion: Of the three surgicalstrategies, ventral decompression withfusion resulted in the most significant 1-year functional improvement whentreating 3-4 levels of spondylosis. Inaddition, ventral decompression withfusion is a cost-effective treatment optionfor CSM when compared to dorsallaminectomy both with and withoutfusion.

112Functional and Quality of Life Outcomesin Geriatric Patients with Type II OdontoidFracture: One-Year Results from theAOSpine North America Multicenter GOFProspective StudyMichael G. Fehlings, Alexander R. Vaccaro,Branko Kopjar, Jens Chapman,Christopher I. Shaffrey, Paul M. Arnold,Ziya L. Gokaslan, Roger Hartl, Darrel S. Brodke, John France, Sangwook Yoon, Mark B. Dekutoski, Rick Sasso, Christopher Bono Introduction: Odontoid fracturescommonly occur in the elderly andrepresent a management challenge. It isunclear whether surgery or conservativemanagement is the best treatmentoption. Moreover, there is a paucity ofinformation regarding treatmentoutcomes.Methods:We conducted a prospectivemulticenter cohort study of subjects > 65years old with a Type II odontoid fractureat 13 sites in North America. Patientsreceived nonoperative or surgicaltreatment at the discretion of the surgicalteam and were followed for 12 months.Outcomes assessments included theSF36, Neck Disability Index (NDI) andrates of mortality and complications.

Results: A total of 166 subjects wererecruited (average age: 80.7 (SD 7.6));59.6% females of whom 65.6% weretreated operatively (15.2% anteriorodontoid screw; 76.2% posterior C1- C2screw fixation; 6.7% posteriortransarticular screw fixation and 1.9%other). A total of 26 (15.7%) subjectsexpired and 5 subjects withdrew from thestudy. Follow-up was available for 100(74%) of 135 eligible, surviving subjects.The baseline NDI was 21.9 (SD 17.0) andSF36v2 PCS was 41.0 (SD 10.5). At 12months, the NDI worsened by 7.5 (SD18.1) points (P < .001) and SF36v2 PCSdeclined by 2.3 (SD 10.4) points (P = .03).There was a significant difference in NDIoutcomes between the surgically and theconservatively treated group. The declinein NDI among the surgical cases was 4.7points compared to 13.0 points in theconservatively treated group (P = .017).There were no differences in the SF36v2PCS outcomes between the treatmentgroups.Conclusion: In spite of treatment, elderlypatients with Type II odontoid fractureexperience significant mortality anddecline in functional outcomes at oneyear follow-up. Our results do suggestthat NDI outcomes may be better in thesurgical group, though the possibility ofselection bias needs to be carefullyconsidered.

113Prospective, Randomized, MulticenterStudy of Cervical Arthroplasty: 269Patients from the Kineflex/C Metal-on-Metal Artificial Disc IDE Study withMinimum Two-Year Follow-upDomagoj Coric, Richard D. Guyer, Pierce D. Nunley, Charley Gordon, Thomas Dimmig, Cameron Carmody,Donna D. Ohnmeiss, Margaret BoltesIntroduction: This prospective,randomized, multicenter study evaluatesthe safety and efficacy of a new metal-on-metal cTDR implant (the arthroplasty) bycomparing it to ACDF.Methods: The study was a prospective,randomized FDA IDE pivotal trialconducted at 21 centers across the US.The primary clinical outcome measuresincluded the Neck Disability Index (NDI),visual analog scales (VAS), and acomposite measure of clinical success.Patients were evaluated clinically andradiographically preoperatively and at1.5, 3, 6, 12, and 24 months after surgery.Results: A total of 269 patients wereenrolled and randomly assigned to eithercTDR (n=136) or to ACDF (n=133). Theoverall success rate was significantly

greater in the cTDR group (74%)compared to the ACDF group (62%)(p=0.05). In both the cTDR and ACDFgroups, the mean NDI and VAS scoresimproved significantly by 6 weeks aftersurgery and remained significantlyimproved throughout the 24-monthfollow-up (p<0.001). The range of motion(ROM) in the cTDR group wassignificantly greater than the pre-op at12- and 24-month follow-up. Adjacentlevel degeneration was also evaluated inboth groups from pre-op to 2 year follow-up and classified as: none, mild,moderate or severe. Pre-op, there were nosignificant differences between groupswhen evaluating the different levels ofadjacent level degeneration. However, at2 year follow-up, there were significantlymore patients in the ACDF group withsevere adjacent level radiographicchanges (p<0.01).Conclusion: The arthroplasty wasassociated with a significantly greateroverall success rate compared to fusionwhile maintaining motion at the indexlevel. Furthermore, there were asignificantly fewer arthroplasty patientsshowing severe adjacent level radiographicchanges at two year follow-up. Theseresults from a prospective, randomizedstudy support that arthroplasty cTDR is aviable alternative to ACDF in selectpatients with cervical radiculopathy.

114Cervical Disc Replacement: Interim Five-year Follow-up Results from the UnitedStates Prospective Randomized BryanClinical TrialRichard G. Fessler, Rick Sasso, Paul Anderson, John Heller Introduction: The purpose of this study isto evaluate the currently available data athalf of a decade to determine theirconsistency over time and to assesscomplications and revision surgeries.Methods: 463 patients were enrolled andreceived the study surgical treatments ina prospective, randomized, controlled,multicenter study with a 1:1randomization scheme. No statisticaldifferences were seen between the groupsfor demographics and preoperativemeasures. As of May 28, 2010, 5-yearfollow-up data were available for 193/242(79.8%) of the arthroplasty patients and159/221 (71.9%) of the control patients.The study’s primary outcome measure,overall success, as well as secondaryfunctional outcome measures (NDI, SF-36, arm and neck pain scores), werecollected at pre-defined time points outto 60 months postoperatively.




Results: At 60 months: Overall successrate: 160/193 (82.9%) for the arthroplastygroup, 119/159 (74.8%) for the controlgroup, p=0.043; NDI score: 15.9arthroplasty, 19.1 control, p=0.020(Change from preop: -35.6 arthroplasty, -30.2 control, p=0.020); Neck pain score:23.8 arthroplasty, 28.8 control, p=0.031(Change from preop: -51.3 arthroplasty, -45.2 control, p=0.031); and SF-36 PCS:47.3 arthroplasty, 44.0 control, p=0.006(Change from preop: 14.4 arthroplasty,11.8 control, p=0.006); Cumulatively up to60 months: Second surgery at index level:11 (4.5%) arthroplasty, 11 (5.0%) control;Possibly device-related AEs: 9 (3.7%)arthroplasty, 14 (6.3%) control; Possiblydevice-related and serious (grade 3 or 4)AEs: 4 (1.7%) arthroplasty, 9 (4.1%)control.Conclusion: Excellent results continueout to 5 years in both the arthroplasty andACDF groups. Statistically significantdifferences are present for overall successthat favor the arthroplasty cohort. TheNDI, SF-36 PCS and neck pain scores alsoshowed improvement in the arthroplastygroup that was statistically significant at60 months compared to the controlgroup. Second surgery and adverseevents were very low in both groups withno statistically significant differencesbetween groups at half a decadepostoperatively.

115Are Closed Suction Drains in PosteriorSpinal Surgery “The Devil’s Highway” forInfection?James S. Harrop, Srinivas K. Prasad, John Kevin Ratliff, Mitchell Gil Maltenfort,Phyllis Flomenberg, Ashwini Dayal Sharan,Alex Vaccaro, Shilpa RaoIntroduction: Surgeons advocateplacement of extra-axial subfascial drainsafter posterior spine surgery to reducepostoperative collections (i.e.: hematomas). This may potentiallydecrease neurologic complications andpossibly decrease infectious rates.However, the potential adverseconsequences of increased infection ratedue to foreign body placement have notbeen determined.Methods: A retrospective analysis of aninfection control prospective database ofa single tertiary care surgery populationwas performed over a one-year period.Posterior instrumented spinal fusionprocedures were assessed for surgical siteinfections (SSIs) and analyzed againstcase-controls (1:3 ratio). Specifically, theplacement of subfascial drains and theirduration of placement and how this

correlated was exploredResults: 1587 fusion procedures wereperformed during this one-year period ofwhich 42 posterior instrumented fusionsdeveloped wound site infections (2.6%).Infections were diagnosed a mean of 14.6±9 days post-procedure and skin flora(Staphylococcus aureus) was the mostcommon pathogen (65%). Infectedinstrumented posterior spinal fusionprocedures had a longer duration ofsubfascial drains than controls (median 5days vs. 3 days, respectively [p<0.0001;log-rank test]). At a breakpoint of drainduration > 5 days, the OR of infection was14.2 (95% CI = 5.6-35.9; p < 0.0001)Multivariate logistic regression indicatedthat likelihood of infection increased withdrain duration (Odds Ratio, 1.5 per daydrain present [95% CI, 1.2 - 2.0; p <0.0001]) and was higher for males (OR 2.8;95% CI 1.2-6.6; p = 0.01). Proportionalhazards test determined that theprobability of drains being removed onany given day was lower (i.e., longer drainduration) for infected cases (Risk Ratio0.4, 95% CI=0.3-0.6, p < 0.0001) andpossibly for longer surgeries (RR per hour0.9, 95% CI = 0.8-1.01, p=0.08).Conclusion:The increased duration oftime after the placement of posteriorsubfascial closed suction drains afterinstrumented spinal fusions appears tocorrelate with an increased incidence ofsurgical site infection. Therefore, shorterdurations of time (specifically lesss thanfour days) or elimination of thesedrainage catheters may decrease theoverall infection rates in thissubpopulation of spine surgery patients.

116Clinical and Radiographic Factors Drivingthe Transition from Nonoperative toOperative Treatment in Elderly Adults withDegenerative ScoliosisKai-Ming G. Fu, Justin S. Smith,Christopher I. Shaffrey Introduction: Few studies report thelong-term outcomes of elderly adultdegenerative scoliosis patients treatednonoperatively. In addition, the rate ofcrossover of nonoperatively managedpatients and the factors influencing thiscrossover has not been demonstrated. Inorder to address these questions, weprospectively followed a cohort of suchpatients presenting to a surgical clinic forevaluation.Methods: 92 consecutive adultdegenerative scoliosis patients (age >60,mean 69) were followed prospectivelyupon presentation to the surgical clinic.All were initially managed

nonoperatively. Quantitative measures ofhealth status (SF-12 and ODI), VAS painscores, and radiographic parameters wererecorded. Patient follow-up was recordedat specified biennial time points or whena patient was treated operatively.Statistical analysis was performed via T-Test with a P<0.5 considered significant.Results: 73 patients (79%) were followedfor a minimum of 2 years (mean 2.64years) or became operative patients. Ofthese 18 (25%) went on to have surgery inthe follow-up period with a mean time tosurgery of 1.6 years. There were nodifferences at presentation in age, healthstatus (SF-12, ODI), leg pain, back pain,or sagital balance between those thatcrossed over and those that were“successfully” treated conservatively. Atlast follow-up or pre-surgical follow-up,crossover patients had lower SF-12 scores(P=.033), higher disability scores (p=0.04),and worse back (6.8 vs. 4.8 (p=0.002)) andleg (5.4 vs. 3.0 (p=0.002)) pain. There wereno differences in radiographicparameters. Of note there was nosignificant overall progression of sagittalbalance or maximum coronal curve.Patients continuing conservative therapydid not demonstrate significant changesin SF -12 and ODI scores.Conclusion:There is a significant rate ofcrossover in nonoperatively managedelderly scoliosis patients. Those crossingover reported higher disability and worsepain and health. Patients continuingnonoperative therapy report stable, butnot improved, outcome measures.

117Incidence of Vascular EncroachmentResulting from Free Hand Placement ofPedicle Screws in the Thoracic andLumbar Spine: Analysis of 6,816Consecutive ScrewsScott L. Parker, Anubhav Amin, Ali Bydon,Daniel M. Sciubba, Jean-Paul Wolinsky,Ziya L. Gokaslan, Timothy F. Witham Introduction: Iatrogenic major vascularinjuries during anterior instrumentationprocedures have been reported by severalauthors, but there is a paucity of dataregarding major vascular injuries duringposterior instrumentation procedures.The purpose of this study is to evaluatethe incidence and clinical significance ofvascular encroachment resulting fromfree-hand placement of pedicle screws inthe thoracic and lumbar spine.Methods:We retrospectively reviewedrecords of all patients undergoing free-hand pedicle screw placement withoutimage guidance in the thoracic or lumbarspine between June 2002-June 2009.



AWARDS PROGRAM ABSTRACTS46

Incidence and extent of vascularencroachment by a pedicle screw wasdetermined by review of routinepostoperative CT scans obtained within24 hours of all surgeries. Vascularencroachment was defined as a screwtouching or deforming the wall of a majorvessel.Results:Nine-hundred sixty-four patientsreceived 6816 free-hand pedicle screws inthe thoracic or lumbar spine. Fifteen(0.22%) screws were identified toencroach upon a major vascularstructure. Ten (67%) thoracic screwsencroached on the aorta, 4 (27%) lumbarscrews on the common iliac vein, and 1(6%) S1 screw on the internal iliacvein,Figure 1. The spinal level ofinvolvement is depicted in Figure 2.Consultation with vascular surgery wasutilized to determine if revision surgerywas recommended and thetechnique/approach for the revisionprocedure. Two (11.7%) patients requiredrevision surgery to remove theencroaching pedicle screw (T5 and T8)due to concern for vascular injury. Bothpatients requiring revision wereasymptomatic and recovered withoutfurther complications after revisionsurgery.Conclusion:Vascular encroachment ofmajor vessels occurs rarely in the settingof free-hand pedicle screw placement inthe thoracic and lumbar spine. Althoughrare, delayed vascular injury from errantpedicle screw placement has beenreported in the literature. Aorta is thevessel at highest risk of injury. Routineintraoperative and postoperative CTscanning allows for early identification ofscrews encroaching on vascularstructures thereby facilitating earlyrevision surgery.

118 MAYFIELD BASIC SCIENCE AWARD Evidence of Descending SupraspinalControl of Nociception and Pain Behaviorin Experimental Disc-HerniationRadiculopathyMohammed F. Shamji, Priscilla Hwang,Kyle D. Allen, Mosfata Gabr, J. Chen,Liufang Jing, William J. Richardson, Lori A. Setton Introduction:Disc-herniation inducedradiculopathy involves both mechanicalcompression and biochemicalinflammation of apposed neuralelements.(1-3) Recent evidence suggestsheterotopic disc placement induces earlyand persistent allodynia alongsidetransient pathological gait asymmetry.(1)This suggests divergent molecular effectsat spinal and supraspinal levels. Thisstudy evaluated the inflammatory andanalgesic molecular profile observed atthe dorsal root ganglion (DRG) andmidbrain periaqueductal grey and rednucleus in an animal disc-herniationdisease model.Methods: Sprague-Dawley ratsunderwent surgical procedure includingharvesting autologous nucleus pulposus(NP) from a tail intervertebral disc andexposure of the L5 dorsal root ganglion(DRG). Control animals (n=12)underwent exposure only andexperimental animals received NPplacement onto the DRG (n=12). Animalswere evaluated for mechanical allodyniaand for stance and gait symmetry.Following sacrifice (1 or 4 weeks), theDRG and midbrain were evaluated byimmunohistochemistry for inflammatoryactivation and neurotransmitterreceptors respectively.Results: Persistent mechanical allodyniaoccurred in rats subjected to NPstimulation at 1 and 4 weeks, althoughthis heightened sensitivity had thefunctional consequence of early gaitasymmetry (1 week) with latenormalization (4 weeks) (Figure 1).Injured animals revealed early andpersistent inflammatory glial cell

activation at the DRG, paralleling theallodynia phenotype. Conversely,midbrain studies reveal persistently highglutamate receptor expression, highserotonin receptor expression at 1 weekwith late normalization, and early normalopioid receptor expression with lateescalation at 4 weeks (Figure 2).Conclusion: Persistent mechanicalallodynia with only transient gaitabnormality in this model of non-compressive disc herniation suggestsdeficits to be mediated by both spinal andsupraspinal mechanisms. InflammatoryDRG activation may generate persistentallodynia and promote gait asymmetry.Early midbrain serotonin and glutamatereceptor expression may aggravate thisdeficit while late opioid receptorexpression may permit adaptive responseto normalize behavior.

119 MAYFIELD CLINICAL SCIENCE AWARDPerioperative Use of Dexamethasone inMultilevel Anterior Cervical SpineSurgery: Preliminary Results of aProspective, Randomized, Double-BlindedTrialTyler J. Kenning, Karen Petronis, John W. German, Doniel Drazin, Darryl J. DirisioIntroduction: Anterior approaches to thecervical spine involve some retractionaffecting the midline structures of theanterior neck. Steroids givenintraoperatively may reduce theincidence of adverse outcomes, such asdysphagia and airway compromise. Theiruse has historically been controversialduring spinal arthrodesis procedures dueto concern that anti-inflammatory agentscould reduce bony fusion rates.Methods: A prospective, randomized,double-blinded study in patientsundergoing multilevel anterior cervicalspine surgery is being conducted atAlbany Medical Center. Our hypothesis isthat perioperative steroids decreasepostoperative swallowing and airwaycomplications and don’t impact long-term fusion rates. The target enrollmentis 200 subjects with 2-year follow-up. Thispreliminary data reflects an interimanalysis of the first 53 patients. Westudied patients undergoing multilevel(>2 motion segments) anterior cervicalspine procedures. Patients wererandomized to receive intraoperativedoses of either intravenousdexamethasone (0.2 mg/kg IV; n=28) oran equivalent volume infusion of saline(n=25). Four postoperative doses of0.06mg/kg of steroid or placebo were

AWARDS PROGRAMABSTRACTS

Friday, March 119:00 AM

Grand Saguaro North

An eight-minute presentation bythe primary author is followed by

a short discussion period.



AWARDS PROGRAM ABSTRACTS 47

administered every 6 hours for the first 24hours. Preoperative parameters,includingbaseline demographics, smoking history,pain and functional status(mJOA,NDI,SF-12,VAS), swallowingfunction (functional outcome swallowingscale, FOSS) and diagnosis werereviewed. Postoperative data includedlength of inpatient stay, FOSS, mJOA, VAS,SF-12, and fusion status, assessed by CT,at 6 months. Any postoperativecomplications were noted.Results:There were no statisticaldifferences in preoperative parameters ofage, gender, diagnosis, smoking history,number of operative levels, mJOA, FOSS,NDI, SF-12, or VAS between the 2 groups.FOSS, when assessed in the immediatepostoperative period, was significantlylower in the steroid(S) group whencompared to the placebo(P) group(S:0.59±0.80, P:1.23±0.92, p=0.01). Thissignificance was lost at the 1, 3, and 6-month follow-up. There were nosignificant differences in any of the otherpostoperative measures,including 6month fusion status. One patient in theplacebo group required postoperative re-intubation, and one patient in the steroidgroup required PEG tube placementsecondary to prolonged dysphagia.Conclusion:Our preliminary datasuggests that perioperative steroidsdecrease postoperative swallowing

complications without negativelyimpacting long-term fusion rates.

120 OUTCOMES COMMITTEE AWARDAnalysis of the Three United States FDA-IDE Cervical Arthroplasty TrialsCheerag Upadhyaya, Jau-Ching Wu, Regis W. Haid, Vincent C. Traynelis, Bobby Tay, Domagoj Coric, Gregory R. Trost, Scott A. Meyer, Praveen V. Mummaneni Introduction:There are threerandomized, multicenter, United StatesFDA IDE, industry sponsored studiescomparing arthroplasty with anteriorcervical discectomy and fusion (ACDF)for single level cervical disease withcomplete 2-years of follow-up. Thestudies evaluated the PRESTIGE ST,BRYAN, and ProDisc-C artificial discs. Weanalyzed the combined results of thesethree trials.Methods: A total of 1,213 patients withsymptomatic, single-level cervical discdisease were randomized into twotreatment arms in the 3 randomizedtrials. 621 patients received an artificialcervical disc and 592 patients weretreated with ACDF. 94% of thearthroplasty group and 87% of the ACDFgroup have completed two years offollow-up. We analyzed the 2-year datafrom these three trials including

previously unpublished source data.Statistical analysis was performed withboth fixed and random effects models.Results: Analysis demonstrated preservedsegmental sagittal motion witharthroplasty (preoperatively 7.26 degreesand postoperatively 8.14 degrees) at thetwo-year timepoint. The fusion rate forACDF at two years was 95%. The NDI, SF-36 MCS, SF-36 PCS, VAS neck pain, andVAS arm pain scores were not statisticallydifferent between groups at 24-monthsfollow-up. The arthroplasty groupdemonstrated superior results at 24-months in neurological success (RR0.595, I²=0%, p=0.006). The arthroplastygroup had a lower rate of secondarysurgeries (RR 0.508, I²=0%, p=0.018). Thereoperation rate for adjacent level diseasewas lower for the arthroplasty groupwhen we analyzed the combined data setusing a fixed effects model (RR 2.23,I²=2.9%, p=0.026).Conclusion: Both ACDF and arthroplastydemonstrate excellent two year surgicalresults for the treatment of one levelcervical disc disease with radiculopathy.Arthroplasty is associated with a lowerrate of secondary surgery and a higherrate of neurological success at 2 years.Arthroplasty may be associated with alower rate of adjacent level disease at 2years.

The AANS/CNS Section on Disorders of the Spine and Peripheral Nerves gratefully acknowledges

for providing an educational grant in support ofthe 2011 Annual Meeting

NEUROSURGICAL EDUCATION AMBASSADOR



ORAL POSTER ABSTRACTS48

200Pulsed Electromagnetic Field BoneGrowth Stimulation for High Risk FusionPatients: An Analysis of 452 ConsecutiveCasesNaresh P. Patel, Barry D. Birch, Mark K. Lyons, Richard S. Zimmerman,Stacie DeMent, Gregg Elbert, Orland K. Boucher, Amy Theiler Introduction: Pseudarthrosis occurs inup 10-15% of instrumented spinal fusioncases, often requiring revision surgery (1).High risk patients including diabetics,smokers, and those undergoing multi-level fusion or revision surgery havedemonstrated higher pseudarthrosisrates(1,2). Patients with multiple riskfactors pose an even greater treatmentchallenge(3,4). Bone MorphogeneticProtein (BMP) has been used increasinglyto help promote fusion in high riskpatients, but due to side effects, risks andcost may not be suitable for allpatients(5). The authors describe theirexperience with a consecutive series ofpatients undergoing adjunctive treatmentwith an external bone growth stimulatorto achieve successful fusion.Methods: Between 2001-2009, 452 highrisk patients underwent instrumentedfusion surgery at the Mayo Clinic Arizona.95 cervical and 357 lumbar cases wereidentified. Fusion was performed withiliac crest autograft and allograft in thelumbar spine and allograft alone in thecervical spine. No BMP was used. Eachpatient was fitted with an external pulsedelectromagnetic field bone growthstimulator within two weeks of surgerywhich was worn for at least 2 hours/dayfor a minimum of 6 months. Follow-upwas obtained at two week, three monthand one year postoperatively withradiographs and CT scans.Results: In the cervical fusion group therewere 88 solid fusions and 7 pseudarthroses(92.6% fusion rate). In the lumbar groupthere were 339 solid fusions and 18

pseudarthroses (94.9% fusion rate). Therewere no complications or side effectsassociated with the use of the stimulator.Conclusion: Bone growth stimulationfollowing standard fusion techniques inthis large series of high risk patients led tofusion rates greater that 90% in both thecervical and lumbar spine. Based onefficacy and safety, external bone growthstimulation appears to be a reasonableadjunctive treatment to promote fusionin high risk patients.

201Preservation of Segmental Motion withAnterior Contralateral CervicalMicrodiskectomy and Interbody Fat Graft:Prospective StudyYunus Aydin, Halit Çavusoglu, Cengiz Tuncer, Osman Nuri Türkmenoglu, Ahmet Murat MüslümanIntroduction:The aim of our study is toevaluate the results and effectiveness ofthis minimal invasive technique with orwithout interbody fat graft replacementin patients with cervical paramedian discherniations.Methods:This prospective observationalstudy was undertaken for the analysis of330 patients with cervical paramediandisc herniation who underwent one -oradjacent two-level anterior contralateralmicrodiskectomy without fusion between1992 and 2009. Interbody fat graftraplacement were performed on 91 of 340patients (Group 2). The mean follow uptime was 10 years (range 1 - 16 years).Preoperative and postoperative lateraldynamic cervical radiographs wereobtained and, the presence of a reductionin the height of interspace andspontaneous osseous union at thediskectomy level were investigated.Surgeries were done by the senior author(YA). Clinical outcomes were assessedusing the Neck Disability Index and ShortForm 36.Results:Despite fusion procedures werenot performed, spontaneous radiologicalfusion signs were obtained in 12% ofgroup 1 patients. Follow-up radiologicalstudies revealed healing without fusion ingroup 2 patients. There was no significantchange in the mean overall cervicalcurvature (C2 - 7) angles postoperativelyin late follow-up findings (p = 0.77). Itrepresented a statistically significantmean loss of 2.24 degree of segmentallordosis (p < 0.001). The NDI scoresdecreased significantly in both early andlate follow-up evaluations and the SF-36scores demonstrated significantimprovement in late follow-up results intwo groups. Analysis of clinical outcome

showed no statistical differences betweentwo groups (p = 0.77).Conclusion: Anterior contralateralmicrodiscectomy without fusion achievesbetter exposure for resection of theoffending foraminal or far lateral lesions,ventral osteophytes, or a disc fragmentunder direct microscopic visualization.Collapse, loss of motion and, instability ofthe involved disc level can also beavoided via this less invasive techniqueand interbody fat graft.

202Radiographic Outcomes in Two-levelACDFs: Comparison of PEEK and AllograftInterbody Devices at 1 and 2-Year Follow-upJody A. Rodgers,W.B. Rodgers, Edward J. GerberIntroduction: In our single-siteprospective series of 184 two-level ACDFpatients, 100 had the PEEK interbodydevice, and 84 had the Allograft device. Todate, 60 patients have presented for 24-month follow-up.Methods: 184 patients underwentinstrumented 2-level ACDFs. Patientswere assigned to one of two treatmentsarms that included a composite of DBMplus autogenous endplate reamings,incorporated into allograft bone dowelsor PEEK spacers and stabilized withdynamic anterior plating. Fusion wasdefined as uninterrupted bridging of wellmineralized bone across the interbodyspace and no significant motion onflexion-extension radiographs. Bothoperative levels were assessed for fusionusing a modified Lenke score. Anypseudarthrosis at either level wasconsidered a failure.Results:Of 184 patients, 84 were treatedwith allograft interbody dowels (27M,57F; age 60.8 yrs; 33 smokers) and 100were treated with PEEK spacers (23M,42F; age 52.4yrs; 15 smokers). Average 12-month Lenke score across all subsets was1.07 (allograft 1.15; PEEK 1.01). At 24months, average Lenke scores across allsubsets was 1.03 (allograft 1.10, PEEK1.00). There were no infections,neurologic complications or platebreakages. Only one patient (allograft)developed a clear pseudarthrosis.Conclusion:The combination of ademineralized bone matrix-local bonecomposite contained within allograftdowels or PEEK spacers resulted insimilar fusion rates (> 97%) at 12 monthspostoperatively. Based on Lenke scores,allograft dowels appear to fuse moreslowly than PEEK spacers but this may beperceptional.

ORAL POSTER ABSTRACTSThursday and Saturday,

March 10 at 3:45 PMGrand Saguaro North

Grand Canyon 9March 12 at 6:55 AM & 11:05 AM

Grand Saguaro North

Five-minute presentations by theprimary authors are followed bya short discussion period during

these concurrent sessions.



ORAL POSTER ABSTRACTS 49

203Safety, Efficacy, and Dosing ofRecombinant Human Bone MorphogeneticProtein-2 (rhBMP-2) for PosteriorCervical and Cervico-thoracicInstrumented Fusion with a MinimumTwo-year Follow-upD. Kojo Hamilton, Justin S. Smith, Davis Reames, Brian Jeremy Williams,Daniel R. Chernavvsky, Christopher I. Shaffrey Introduction:Considerable attention hasfocused on concerns of increasedcomplications with rhBMP-2 use foranterior cervical fusion, but few reportshave assessed its use for posterior cervicalfusions. This study evaluates the safety,efficacy, and dosing of recombinanthuman bone morphogenetic protein(rhBMP-2) as an adjunct forinstrumented posterior cervicalarthrodesis using a retrospectiveconsecutive case series.Methods: All patients were treated by thesenior author with posterior cervical orcervico-thoracic instrumented fusionaugmentated with rhBMP-2 and hadminimum follow-up of two-years.Diagnosis, levels fused, rhBMP-2 dose,complications, and fusion (Lenke gradeapplied by two neuroradiologists) wereassessed.Results: 53 patients (22 men/31 women)met inclusion criteria, with a mean age of55.7 years and an average follow-up of 40months. Surgical indications includedbasilar invagination (n=6), fracture (n=6),atlanto-axial instability (n=16),kyphosis/kyphoscoliosis (n=22),osteomyelitis (n=1), spondylolisthesis(n=1), cyst (n=1). 15 patients hadconfirmed rheumatoid disease. Theaverage rhBMP-2 dose was 1.79mg/levelwith a total of 282 levels treated. Among53 patients, only 2 complications (3.8%)were identified, a superficial woundinfection and an adjacent leveldegeneration. At last follow-up, allpatients had achieved fusion.Conclusion: Augmentation of posteriorcervical fusion with rhBMP-2 appears tobe safe and has a very low complicationrate. Despite complex pathology and/orrheumatoid arthritis, a 100% fusion ratewas achieved, which is considerablyhigher than comparable historicalcomparisons without rhBMP-2 (62-94%).Collectively, these data suggest that use ofrhBMP-2 as an adjunct for posteriorcervical fusion is safe and effective at anaverage dose of 1.8mg per level.

204Prospective Results from the US IDEFeasibility Study of a Novel Peek-On-PeekNucleus Replacement Device withMinimum Two-Year Follow-upDomagoj Coric, Matthew Songer, John J. Regan Introduction:Nucleus replacement(partial disc replacement) offers a lessinvasive alternative to traditional fusionor total disc replacement techniques inthe treatment of symptomatic lumbardegenerative disc disease (DDD).NUBACTM is the first PEEK-on-PEEKarticulated intradiscal arthroplastydevice. The authors report the results of20 consecutive patients treated withNUBAC nucleus replacement in theprospective, multicenter US FDA IDEfeasibility clinical study. On the strengthof the results of this pilot feasibility study,NUBAC became the first nucleusreplacement device to enter US IDEpivotal study.Methods: Patients with symptomaticDDD at L4-5 were enrolled at threeinvestigational sites in the IDE feasibilitystudy. All devices were placed via a lateraltranspsoas approach. Effectiveness isevaluated by prospectively recording pre-op and post-op (at 1.5, 3, 6, 12 and 24months) Oswestry Disability Index (ODI)and Visual Analog Scale (VAS) scores.Results: A total of 20 NUBAC devices wereimplanted in 20 patients. Average ORtime was 124 minutes; EBL was 47 cc.Average time to discharge home was 1.4days. There were no major intra- orpostoperative neurological or vascularcomplications. Average age=41 years.Clinical results showed statisticallysignificant improvement in pain reliefand function compared to preop at alltime intervals. The mean preoperativeVAS (7.1) and ODI (53.9) scores improvedsignificantly at six weeks (3.4 and 30.7,respectively) and were maintainedthrough 2 years (1.8 and 6.3, respectively).There were no device expulsions orreoperations.Conclusion:This early, prospectiveclinical experience with NUBAC PEEK-on-PEEK nucleus replacement ispromising. NUBAC is currently inprospective, randomized, multicenterFDA IDE pivotal study and those resultswill continue to define the role of nucleusreplacement in the treatment ofsymptomatic DDD.

205Preoperative Grading Scale To PredictSurvival in Patients Undergoing Resectionof Malignant Primary Osseous SpinalNeoplasmsScott Parker, Kaisorn L. Chaichana, Oran Aaronson, Joseph S. Cheng, Ziya L. Gokaslan, Matthew J. McGirt Introduction: Large population-basedstudies of malignant primary osseousspinal neoplasms are lacking and arenecessary for sufficient power todetermine prognostic factors. Using a 30-year U.S. national cancer registry (SEER),we introduce a preoperative grading scalethat is associated with survival in patientsundergoing surgical resection formalignant primary osseous spinalneoplasms.Methods:The SEER registry (1973-2003)was queried to identify adult patientsundergoing surgical resection ofhistologically confirmed primary spinalchordoma, chondrosarcoma, orosteosarcoma via ICD-O-2 coding.Variables independently associated withsurvival were determined via Coxproportional-hazards regression analysisfor all tumor types. A grading scalecomprised of these independent survivalpredictors was then developed andapplied to each histology-specific tumorcohort.Results: 342 patients were identified thatunderwent surgical resection of amalignant primary osseous spinalneoplasms (114 chordoma, 156chondrosarcoma, 72 osteosarcoma).Overall median survival after surgicalresection was histology specific(osteosarcoma: 22 months; chordoma:100 months; chondrosarcoma: 160months). Increasing age (years) andincreasing tumor extension (1. confinedto periosteum; 2. invasion throughperiosteum into adjacent tissues; 3. distalsite metastasis) were the only variablesindependently associated with decreasedsurvival (p<0.05) for all tumor types. Forspinal chordoma, sacrum/pelvic location(p<0.05) and earlier year of surgery(p<0.005) were also independentlyassociated with decreased survival.Utilizing variables of patient age, extent oflocal tumor invasion, and metastasisstatus in a five-point grading scale,increasing score (1-5) closely correlated(p<0.001) with decreased survival forchordoma, chondrosarcoma, andosteosarcoma, Figure 1.Conclusion: In our analysis of a U.S.population based cancer registry (SEER),a grading scale consisting of age,




metastasis status, and extent of localtumor invasion was associated withoverall survival after surgical resection ofchordoma, chondrosarcoma, andosteosarcoma of the spine. This gradingscale may offer valuable prognostic databased on variables available to thesurgeon and patient prior to surgery andmay help guide level of aggressiveness insubsequent treatment strategies.

206Clinical Outcomes Following En BlocSacrectomies via Posterior ApproachMichelle J. Clarke, Daniel M. Sciubba,Matthew J. McGirt, Timothy F. Witham, Ali Bydon, Patrick C. Hsieh, Ziya L. Gokaslan, Jean-Paul Wolinsky Introduction: En bloc resection ofprimary sacral tumors has ademonstrated survival benefit. Total andhigh sacral amputations traditionallyinvolved both an anterior and posteriorapproach. However, we have found thaten bloc resection and biomechanicalreconstruction is possible from aposterior-only approach in many cases.Methods: Sixty-nine consecutive patientsunderwent sacral resections for tumor atour institution between 2004 and 2009.Medical records of all patients werereviewed, and patients were excluded ifthey had an intentional intralesionalresection, hemipelvectomy or werepreviously operated. The records of theresulting 37 consecutive patients whounderwent primary posterior-only enbloc sacral resections and all 4 patientswho underwent a traditional anterior-posterior en bloc sacrectomy wereretrospectively reviewed.Results: All posterior-only patientsunderwent midline posterior approachesfor en bloc sacral resection. Surgical levelwas defined by the anatomic level of therostral osteotomy site: total withlumbopelvic reconstruction (L5S1; n=5),high (S1S2; n=9), middle (S2S3; n=17),and low (below S3; n=6). Chordoma wasthe most common tumor (n=30) andwide surgical margins were attained in 35cases. The level of sacral amputationcorrelated with estimated blood loss(p<0.005), and length of stay (p<0.001).There were 14 complications including 9wound infections/revisions. In theanterior-posterior cohort (n=4), rectalcarcimoma was the most commondiagnosis. Patients required anterior-posterior procedures because of rectalinvasion (n=3) or tumor extending abovethe L5S1 disc space (n=1). All 4 patientssuffered wound complications, and therewas 1 life-threatening hemorrhage.

Operative time, blood loss, and length ofstay was higher than similar posterior-only procedures. In both cohorts, extentof root sacrificed correlated withfunctional outcome.Conclusion: It may be possible toperform a posterior-only approach to enbloc sacral resections/reconstructions inpatients with tumors that do not extendbeyond the lumbosacral junction orinvade the bowel.

207Generation of Chordoma Cell Line, JHC7,and the Identification of Brachyury as aNovel Molecular TargetWesley Hsu, Ahmed Mohyeldin, Sagar R. Shah, Lakesha Johson, Neda I. Sedora-Roman, Thomas Kosztowski, Colette Ap Rhys, Ola Awad, Edward McCarthy, David Loeb,Jean-Paul Wolinsky, Ziya L. Gokaslan,Alfredo Quinones-Hinojosa Introduction: Recent genomicinterrogation of chordomas has identifiedBrachyury gene duplication as a majorsusceptibility mutation in familialchordomas. Current understanding of therole of this transcription factor inchordoma is limited due to the lack of afully characterized chordoma cell lineexpressing Brachyury. We report theestablishment of the first fullycharacterized primary chordoma cell line(JHC7) expressing Brachyury anddemonstrate that silencing of Brachyuryusing shRNA leads to complete growtharrest in vitro.Methods: Establishment of ChordomaCell Line Intraoperatively obtainedchordoma specimen was dissociated intosingle cells using techniques publishedpreviously. Confluent cells were passagedto adherent cell culture flasks forexpansion. Chordoma cells (JHC7) weremaintained in DMEM/F12 (10% FBS)with antibiotic/antimycotic. LentiviralTransduction A pKLO.1-based lentiviralvector containing shRNA targetingBrachyury was obtained from the TRC-Hs1.0 library from Open Biosystems.Brachyury shRNA and empty plasmidswere packaged into lentivirus bytransfecting 10µg of packaging plasmidsin packaging cells. Forty-eight hours aftertransfection, lentiviral supernatant wasused to infect JHC7 chordoma cells.Growth curve studies were performedusing the MTT assay 10 days aftertransduction.Results: A novel chordoma cell line wascreated (JHC7). Cultured cells weremorphologically identical to classicalchordoma, including the characteristic

physaliferous phenotype (Figure 1A). Thepresence of Brachyury was confirmed byWestern Blot and immunohistochemistry(Figure 1B, C). Loss of Brachyuryexpression after shRNA transduction wasconfirmed by Western Blot (Figure 2A).Loss of Brachyury expression abolishedthe classical phenotype of chordoma cellsand led to a more differentiated,epithelial-like state (Figure 2B) with anear complete loss of proliferationcapacity (Figure 2C).Conclusion: The JHC7 chordoma cell linerepresents the first in vitro system withchordoma cells characterized forBrachyury expression. We propose thatshRNA-mediated suppression ofBrachyury is a novel and attractivetherapeutic target in the treatment ofchordoma.

208Reconstruction of Extensive Defects fromPosterior En Bloc Resection of SacralTumors Using Human Acellular DermalMatrix and Gluteus MaximusMyocutaneous FlapsHormuzdiyar H. Dasenbrock, Michelle J. Clarke, Ali Bydon, Timothy F. Witham, Daniel M. Sciubba,Oliver P. Simmons, Ziya L. Gokaslan, Jean-Paul Wolinsky Introduction: Performing a sacrectomysolely from a posterior approach allowsfor the en bloc resection of tumorswithout the additional morbidity of alaparotomy. However, the reconstructionof the resultant extensive soft-tissuedefects is challenging, particularly as avertical rectus abdominis myocutaneousflap is not harvested. We report the largestseries (with the longest follow-up) ofsacral reconstructions using acombination of human acellular dermalmatrix (HADM) and gluteus maximusmyocutaneous flaps.Methods: 34 patients with sacral tumorswho had a follow-up of at least one yearwere reviewed retrospectively.Intraoperatively, after the tumor wasexcised, HADM (AlloDerm) was securedto create a pelvic diaphragm.Subsequently, the gluteus maximusmuscles were freed from their origins,elevated, rotated or advanced in themidline to cover the HADM, and suturedtogether.Results: The mean age of the patients was50 years and the histopathology revealeda chordoma in 82.4%. 8 patients (23.5%)developed a postoperative wounddehiscence, of whom 6 (17.6%) requiredoperative debridement. An estimatedblood loss of >2500 mL and an operative




time of >9 hours during sacrectomy, aswell as postoperative bowel or bladderincontinence, were all associated with asignificantly higher rate of subsequentdebridement procedures (p=0.018). Theaverage length of hospital stay was 12.2(range 3-66) days; the development of asurgical site infection and theperformance of a debridement procedurewere both associated with a longer lengthof hospital stay (p=0.037). With a meanfollow-up of 45.7 months, only 1 patientdeveloped an asymptomatic para-sacralhernia, which was adjacent to a localtumor recurrence.Conclusion: Reconstruction of posteriorsacrectomy defects with HADM andgluteus maximus myocutaneous flapsmay be a valid technique. This approachmay have rates of wound dehiscencecomparable to other techniques and lowrates of para-sacral herniation.

209En Bloc Resection of Cervical Chordomas:Series of 12 Patients and ClinicalOutcomesDaniel M. Sciubba, Camilo A. Molina, Ziya L. Gokaslan, Dean Chou, Jean-PaulWolinsky, Timothy F.Witham, Ali Bydon,Christopher P. Ames Introduction: Chordomas of the mobilespine often undergo en-bloc resectionwith reconstruction to optimize localcontrol and possibly offer cure. In thecervical spine, local anatomy ischallenging and obtaining clean marginsmay be limited. Complications may alsobe higher due to juxtaposition of the skullbase, vasculature, aerodigestive systemand upper spinal cord. In this review, wepresent a series of 12 cases of cervicalchordomas removed en-bloc. Particularattention was paid to clinical outcome,complications, and recurrence. Inaddition, outcomes were assessedaccording to position of tumor in C1/C2vs. the subaxial spine.Methods: The patients undergoing en-bloc resection of cervical chordoma werereviewed from two large spine centers.Patients were included if the lesionepicenter was involving C1 to C7vertebral bodies. Demographics, detailsof surgery, follow-up course, andcomplications were obtained. Outcomewas correlated with presence of tumor inC1/2 vs. subaxial spine(C3-C7) via astudent’s t-test.Results: 12 patients were identified with amean age at presentation of 60. 7/12(58%) and 5/12 (42%) of cases involvedthe C1/C2 and subaxial spine,respectively. En-bloc resection was

attempted via an anterior approach in33% of cases (29%-C1/C2; 40%-subaxial),a posterior approach in 25% of cases(43%-C1/C2; 0%-subaxial), and acombined approach in 42% of cases(29%-C1/C2; 60%-subaxial). Tumormargins were found to be wide in 2/12(17%-overall; 14%-C1/C2; 20%-subaxial),marginal in 6/12 (50%-overall; 29%-C1/C2; 80%-subaxial), or contaminatedin 3/12 (25%-overall; 43%-C1/C2; 0%-subaxial) of cases. No operativecomplications were encountered.Postoperative complications occurred in5/12 (42%-overall; 57%-C1/C2; 20%-subaxial; p<0.05) patients and included:hoarseness, dysphagia,prolonged/permanent use of a feedingtube, and pneumonia. Average follow-upwas 42 months (range 30-60 months).Recurrence occurred in 5/12 (42%-overall; 57%-C1/C2; 20%-subaxial;p<0.05) cases. Of note, in comparingC1/C2 tumor resections with subaxiallesions, we found a greater incidence ofpostoperative complications and rates ofrecurrence.Conclusion: En-bloc resection of cervicalchordomas involving the upper cervicalspine(C1-2) are associated with pooreroutcomes such as higher rates ofcomplications, and recurrence.

210Identification of Cancer Stem Cells inHuman ChordomaWesley Hsu, Ahmed Mohyeldin, Sagar R. Shah, Thomas Kosztowski,Lakesha Johnson, Ola Awad, Neda I. Sedora-Roman, David Loeb,Edward McCarthy, Jean-Paul Wolinsky,Ziya L. Gokaslan, Alfredo Quinones-Hinojosa Introduction: Chordomas are the mostcommon malignant primary tumor of theosseous spine. The mechanismsunderlying the resistance of chordoma tochemotherapy and radiation therapy isunknown. The role of cancer stem cells(CSCs) in chordoma pathophysiology hasnot been defined. We have performed aseries of experiments that provideevidence for the presence of CSCs withinhuman chordoma.Methods: Establishment of ChordomaSarcospheres: Chordoma tumor sampleswere dissociated into single cells, platedin adherent conditions, and expanded toconfluence. Cells were then transferredinto serum-free, non-adherent conditionsto form sarcospheres. DifferentiationStudies: For adipogenic differentiation,chordoma sarcospheres were plated at100% confluency and differentiated using

a commercial human adipogenicdifferentiation kit. Differentiation wasevaluated using oil red staining usingnormal human mesenchymal stem cellsas a positive control. For neuronal andastrocyte differentiation, chordomasarcospheres were maintained in serumfree media and plated in 10% FBS for 10days. Xenograft Studies: BALB/c malenude mice were injected subcutaneouslywith either chordoma sarcospheres(500,000, 1 million, or 2 million cells) ornon-sphere chordoma cells in 50 ulPBS:Matrigel (1:1).Results:We have established a stablechordoma cell line that ismorphologically identical to classicchordoma with expression of brachyury,S100 and keratin. Using this cell line, wehave isolated and characterizedchordoma sarcospheres that are self-perpetuating and exhibit higherexpression of the functional stem cellmarker ALDH1 compared to typicalchordoma cells. Furthermore,sarcospheres can be successfullydifferentiated into neuroepithelial andmesodermal cell types. Subcutaneousinjection of chordoma sarcospheres intoan athymic mouse host induced theformation of tumors that successfullyrecapitulated the phenotypiccharacteristics of the parent chordoma.Conclusion:We present the first evidencefor the existence of chordoma CSCs andhave developed the first animal model forthis disease.

211Sacral Laminoplasty for the Treatment ofSymptomatic Sacral Perineural (Tarlov)Cysts, Clinical Outcomes and SurgicalObservationsZachary Adam Smith, Larry T. Khoo Introduction: The surgical treatment ofsymptomatic sacral perineural cysts orTarlov cysts remains controversial.Traditional approaches have beendescribed using sacral laminectomy. Ouraim was to evaluate the efficacy andpotential complications of treatment ofthese cysts with microsurgicalfenestration, local muscle/fat grafting,and laminoplasty of the sacral lamina.Methods: This is a retrospective study of17 prospectively followed patients with 19large sacral perineural cysts (averag-2.40cm, range 1.1-8.0 cm) of the sacrumtreated by the senior author between May2004 and June 2010. All patientspresented with symptoms non-responsive to medical treatment.Presenting symptoms includedcoccydynia (n=17), radiculopathy (n=14),




back pain (n=11), perineal parasthesias(n=8), incontinence (n=8), and weakness(n=6). We performed a sacrallaminoplasty with fenestration of the cystwith intraoperative electromyography inall patients. All patients had closuresreinforced with either fat or muscle graftwith fibrin glue with subsequent fixationof the sacrum with titanium mini-plates.Outcomes were evaluated by telephonequestionnaire or clinic follow-up ataverage 12.5 months (range 4-44 mo).Results: After surgery, coccydynia (13/17pts, 76.5%), radicular pain (11/14 pts,78.6%), and perineal parasethesias (6/8,75.0%) improved most consistentlyfollowing operation. One patient withoutpre-existing sensory symptomsdeveloped new perineal parasethesias.Bladder control returned in 5 of 8 patients(62.5%) and a single patient developednew bowel and bladder incontinence.There was a single cerebrospinal fluidleak that required return to OR. MRI wascompleted in all 14 patients with >6-month follow-up and no imagingdemonstrate evidence of recurrence.Conclusion:Microsurgical fenestrationwith laminoplasty is a safe and effectivetreatment for carefully selected patientswith large, symptomatic Tarlov cysts. Theauthors describe their results for thissubset of patients who may benefit fromsurgery.

212Hydrostatic Strength Dural Patch RepairMaterialsMichael A. Finn, Paul Anderson, Nathan Faulkner Introduction:We hypothesize thatdifferent dural patch materials will vary intheir initial hydrostatic strength and thatthe use of a biologic glue will increase thehydrostatic strength of dural patchrepairs.Methods:Twenty-four calf thoracicspines were prepared with laminectomiesand spinal cord evacuation, leaving thedura intact. Foley catheters were inflatedon either side of a planned dural defectand baseline hydrostasis was measuredusing a fluid column at 30, 60 and 90 cmof water. A standard dural defect (1x2cm)was created and 8 patches of eachmaterial (human fascia lata, Duragen,and Preclude) was sutured in place usinga 5-0 Prolene HS running suture.Hydrostasis was again tested at the samepressures. Finally, Duraseal was placedover the defect and hydrostasis was againtested. Results were analyzed withANOVA.Results: Leakage rate increased

significantly at each pressure tested for allconditions. All patch materials allowedsignificantly greater leakage than theintact condition. There was no differencein leakage between the three patchmaterials. The use of duraseal reducedleakage significantly at all pressures whenused with Duragen, and at 90 cm of waterwhen used with Preclude. There was atrend towards reduced leakage withduraseal under the remaining conditions.There was no significant differencebetween the Duraseal group and theintact dura.Conclusion:The use of all three duralpatch materials were of similarhydrostatic strength and allowed greaterleakage than intact. The use of Durasealreduced leakage rates to levels similar toinact.

213Hydrostatic Comparison of Titanium Clipand Suture Repair of DurotomyMichael A. Finn, Paul Anderson, Nathan Faulkner Introduction:We hypothesize that thehydrostatic strength of durotomy repairswill vary with the type of suture used andbetween suture and non-penetratingtitanium dural clips.Methods:Twenty-four calf thoracicspines were prepared with laminectomiesand spinal cord evacuation, leaving thedura intact. Foley catheters were inflatedon either side of a planned dural defectand baseline hydrostasis was measuredusing a fluid column at 30, 60 and 90 cmof water. A standard 1 cm durotomy wascreated and was repaired in 8 specimenseach using 5-0 Surgilon, 5-0 Prolene HS,or non-penetrating dural clips.Hydrostasis was again tested at the samepressures. The time required for eachrepair was measured. Results wereanalyzed with ANOVA.Results: Leakage rate increasedsignificantly at each pressure tested for allconditions. There was no differencebetween the intact condition and thetitanium clip repair at any pressure. Therewas significantly greater leakage thanintact in both suture repair groupsdetected at all pressures. There was nodifference between the suture types. Cliprepairs took approximately half as long assuture repairs, a significant difference.Conclusion:The use of non-penetratingtitanium dural clips provided betterimmediate hydrostasis and took less timethan tradition suture repair.

214Prospective Randomized Controlled Trialin Spine Patients to Compare Low SwellFormulation of a Polyethylene GlycolHydrogel Spinal Sealant with OtherMethods of Dural SealingKee Duk Kim, Joseph S. Cheng, Randall Matthew Chesnut, Dean Chou,Haroon F. Choudhri, Rees Cosgrove,Shankar Prakash Gopinath, R. Scott Graham, Richard Gray, Ajit A. Krishnaney, Paul C. McCormick,Ehud Mendel, Jon Park, Mark Edwin Shaffrey, Nathan E. Simmons,John M. Tew, Jack E. Wilberger, Neill Marshall Wright Introduction: As an adjunctive measureto sutured dural repair, spine surgeonsutilize a variety of methods to ensure thatno active leak is present before closingthe wound. In 2009, the FDA approvedthe DuraSeal™ spinal sealant specificallyas an adjunct to sutured repair duringspine surgery. This IDE study comparedthe safety and efficacy of low swell (10%and 39% of its original volume) PEGhydrogel formulation to other methods ofdural sealing.Methods: Prospective, multicenter,randomized controlled study wasconducted to compare a low swellformulation of a PEG hydrogel with othercommon dural sealing methods as anadjunct to sutured dural repair. Toevaluate those patients operated only inspine, Chiari malformation surgery wasexcluded. The primary endpoint was theefficacy of intraoperative watertight duralclosure confirmed by Valsalva maneuverat 20-25 cm H2O. Safety was measured bythe assessment of postoperative CSF leakand surgical site infection.Results: 51 patients were randomized tolow swell PEG hydrogel spinal sealant(treatment) and 16 patients to othermethods of dural sealing such asadditional sutures and/or adhesive glue(control). Efficacy measured byintraoperative watertight closure washigher in the treatment group comparedto the control (98% vs. 75%, p=0.010). Alsotreatment group had lower rate ofpostoperative CSF leak compared to thecontrol (2% vs. 12.5%, p=0.143) and lowerrate of surgical site infection (6% vs.18.8%, p=0.148).Conclusion:Common methods forachieving a watertight dural closureduring spine surgery include the use ofadditional sutures and adhesive glue.With this method, however, about 3 out of4 patients fail to achieve a watertightdural closure. Low swell PEG hydrogel




spinal sealant is much more effective inachieving intraoperative watertight duralclosure without compromising the safetyof the patients.

215Assessment of Thoracic LaminarDimensions in a Pediatric Population: ACT-Based Feasibility Study for PediatricThoracic Translaminar Screw PlacementCamilo A. Molina, Christopher Chaput,Daniel M. Sciubba, P. Justin Tortolani,George I. Jallo, Ryan M. Kretzer Introduction:Translaminar screws (TLSs)were originally described by Wright as asafer alternative to pedicle screw fixationat C2.1 More recently, TLSs have alsobeen used as bail-out procedurefollowing failed pedicle screw placementin the treatment of adolescent idiopathicscoliosis.2,3 To date, there are no studiesthat report the anatomical features of thethoracic lamina in the pediatricpopulation.Methods: 52 patients (26 male, 26female), average age 9.5 4.8 years, wereselected by retrospective review of atrauma registry database after IRBapproval. Study inclusion criteria wereages 2 to 16, standardized axial bone-windowed CT images of the thoracicspine, and an absence of spinal trauma.For each thoracic lamina the followinganatomical features were measured usingeFilm Lite software: width (outer corticaland cancellous), maximal screw length,optimal screw trajectory, and laminarheight. Subjects were stratified by age asfollows: <8 yrs. of age(yo) vs. >8 yrs. ofage(yo) based on presumed spinalmaturity.Results:Collected data (Table 1)demonstrate the following trends: 1)decreasing maximal screw length, 2)stable lamina width (Figure 1), 3)increasing laminar height, and 4)increasing ideal screw trajectory angle asone descends the thoracic spine from T1-T12. When stratified by age, subjects >8yohad significantly larger lamina in bothwidth and height, and allowedsignificantly longer screw placement at allthoracic levels than the <8yo subgroup(p<0.05). Importantly, all thoracic spinallevels had an average bicortical diametergreater than 3.5 mm, indicating that a 3.5mm screw could be placed in themajority of cases.Conclusion:The data collected providepreliminary information regardingoptimal TLS length, diameter, andtrajectory for each spinal level in thepediatric thoracic spine. Furthermore,based on CT evaluation, bicortical width

provides no anatomical limitation to theplacement of translaminar screws in thepediatric population.

216CT Hounsfield Units for Assessing BoneMineral Density: A Tool For OsteoporosisManagementPaul A. Anderson, Joseph Schreiber Introduction:Osteoporosis is a commondisease with enormous implications foraffected individuals and society as awhole. Measurements obtained fromcomputed tomography (CT)examinations obtained for other reasons,may yield information regradingdecreased bone mineral density, withoutadded expense to the patient. Thepurpose of this study was to determine ifHounsfield Units, the standardizedcomputed tomography attenuationcoefficient, correlate with bone mineraldensity (BMD) as measured by DEXA.Methods:Twenty-five patients mean age71.3 years undergoing both lumbar spineDual-Energy X-Ray Absorptiometry(DEXA) scans and CT were evaluated. In aregion of interest, the Hounsfield Unitswas measured and correlated with DEXABMD and DEXA T-scores. Normative datawas generated from CT performed on 80trauma patients.Results:HU decreased relatively linearlyby decade ranging from a mean of 255.1in the second decade to 78.7 in the ninthdecade. Mean HU for the 25 subjects was107.1(36.8). Mean T-score was -1.42(1.51)and BMD 1.104(0.186)g/cm². Strongcorrelations were found betweenHounsfield Units and bone mineraldensity, age, T-scores (p < 0.0001), Figure 1 and 2. The mean HU and 95%confidence intervals for normal,osteopenic, and osteoporotic subjectswere 133.0(CI 118.4 - 147.5), 100.8(CI 93.1- 108.8), and 78.5(CI 61.9 - 95.1).Conclusion:CT Hounsfield Unitscorrelate strongly with DEXA scores, andcan potentially provide an alternativemethod in determining regional bonemineral density at no additional cost tothe patient. The information couldconceivably be applied toward fracturerisk assessment, diagnosis ofosteoporosis, and early initiation ofneeded treatment. While we are notrecommending CT as a substitute forDEXA, when a CT has been obtained forother reasons, regional HU can bemeasured to aid surgical decision makingand as a guide for further testing.

217Effects of Epidural Steroid Injections onBlood Glucose Levels in Patients withDiabetes MellitusOwoicho Adogwa, Jesse Even, Kirk McCullough, Clint Devin, Matthew J. McGirt Introduction: Epidural steroid injections(ESI) are commonly used in the treatmentof multiple spinal disorders.Corticosteroid injections have beenevaluated in the total joints and handliterature showing systemic effects todiabetics. There has not been a clinicalstudy to evaluate if ESI cause systemiceffects in diabetics.Methods:Diabetic patients who werescheduled for an ESI were given anopportunity to enroll in our IRB approvedstudy. We collected the patient’s mostrecent hemoglobin A1c (hA1c) and thenasked them to track their blood glucosenumbers at least twice per day for twoweeks prior to and after their ESI.Results:We noted a statisticallysignificant increase in blood glucoselevels in diabetic patients (N=30) afterepidural steroid injection. The meanblood glucose level prior to ESI injectionwas 157.97 ± 45.71 and after ESI it was304.00 ± 112.63. This represents anaverage 146.03 ± 88.5 increase in bloodglucose levels after injection, which wassignificantly higher than 0 (p=0.0001,Wilcoxon singed-rank test). Using anonlinear mixed effect model theestimated half life of this increase was1.54 days (95% CI 0.86, 7.37), meaningthat the patients were back within theirnormal standard deviation mean glucoselevels within two days of injection. TheSpearman correlation when evaluatingthe association between pre injectionhA1c levels and maximum blood glucosechange was 0.174 (p=0.502) indicatingthere is no correlation between preinjection hA1c levels and systemicresponse to ESI.Conclusion: Epidural steroid injectionswere noted to cause a significant increasein the blood glucose levels in diabetics.There was no correlation between preinjection diabetic control, represented byhA1c levels, and post injection response.Diabetics who are candidates for ESIshould be counseled that a blood glucoseincrease may be apparent postintervention but effects should not lastlonger than approximately two days.




218The Prognostic Value of a CervicalSelective Nerve Root Block: A Correlationwith Surgical OutcomesLuis M. Tumialan, David C. LoPresti,Angelina N. Garvin, Wayne Gluf Introduction:To compare the results of aselective nerve root block in the cervicalspine with surgical outcomes fromposterior cervical foraminotomy oranterior cervical discectomy formanagement of a single level cervicalradiculopathy.Methods:The authors prospectivelyfollowed patients with a unilateral singlelevel cervical radiculopathy. All patientsin this study had radicular symptomswhich correlated with clinical history,neurological examination and MRimaging findings and had failednonoperative management for a minimalperiod of 3 months. All patients wereinitially managed with a CT guidedselective nerve root block. Pre-injection,post-injection and postoperative visualanalogue scores (VAS) were obtained at 0,30 and 90 days. Duration of relief was alsodocumented.Results: A total of 42 patients underwenta transforaminal cervical selective nerveroot block for initial management of theirunilateral single level cervicalradiculopathy. Fifteen of these patientsexperienced recurrence or onlytemporary relief of their symptoms andopted for operative management. At 6months, the remaining 37 patientsrequired no further intervention. Themean preinjection/preoperative VAS was57.1 mm (21-97). The mean post-injection VAS was 15.2 mm (0-45). Themean duration of relief was 20.3 days (1-75). The mean postoperative VAS at 30 days was 18.4 mm (0-60). A regressionanalysis demonstrated that reduction inpain from the baseline VAS to thepostinjection VAS was highly predictive ofoutcomes 30 days after surgery (p = 0.034).The coefficient of determination was 32%.Conclusion:The pain reduction at 30days after a posterior cervicalforaminotomy or anterior cervicaldiscectomy is well predicted by the initialreduction from the selective nerve rootblock. There is prognostic value in thecervical selective nerve root block forprospective surgical patients.

219The Prognostic Value of a LumbarSelective Nerve Root Block: A Correlationwith Surgical OutcomesLuis M. Tumialan, David C. LoPresti,Angelina N. Garvin, Wayne Gluf

Introduction:To compare the results of aselective nerve root block in the lumbarspine with surgical outcomes from amicrodiscectomy for management of asingle-level lumbar radiculopathy.Methods:The authors prospectivelyfollowed patients with a unilateral single-level lumbar radiculopathy. All patients inthis study had radicular symptoms whichcorrelated with clinical history,neurological examination and MRimaging findings and had failednonoperative management for a minimalperiod of 3 months. All patients wereinitially managed with a CT guidedselective nerve root block. Pre-injection,post-injection and postoperative visualanalogue scores (VAS) were obtained at 0,30 and 90 days (when applicable) alongwith preinjection/preoperative andpostoperative Owestry Disability Indices(ODI).Results: A total of 51 patients underwenta transforaminal selective nerve rootblock for initial management of theirunilateral single level radiculopathy.Fifteen of these patients experiencedrecurrence or only temporary relief oftheir symptoms and opted for operativemanagement. At 6 months, the remaining36 patients required no furtherintervention. The mean preinjection/preoperative VAS and ODI was 56.8 mm(17-98) and 23.5 (11-35) respectively. Themean post-injection VAS was 17.25 mm(0-38). The mean duration of relief was18.3 days (0-70). The mean postoperativeVAS and ODI at 30 days were 21.4 mm (0-57) and 13.4 (1-33) respectively. Aregression analysis demonstrated thatreduction in pain from the baseline VASto the postinjection VAS was highlypredictive of outcomes 30 days aftersurgery (p < 0.001). The coefficient ofdetermination was 81%.Conclusion:The pain reduction at 30days after a microdiscectomy is wellpredicted by the initial reduction fromthe selective nerve root block. There isprognostic value in the selective nerveroot block for surgical patients.

220Proximal Junctional Kyphosis in AdultThoracolumbar Instrumented Fusion: Timeto Development, Clinical and RadiographicCharacteristics, and ManagementApproach in 32 Consecutive CasesDavis Reames, Justin S. Smith, D. Kojo Hamilton, Vincent Arlet,Christopher I. ShaffreyIntroduction: Proximal junctionalkyphosis (PJK) is a common mode of

failure following instrumentedthoracolumbar deformity surgery andoften necessitates revision. Our objectivewas to assess the clinical andradiographic factors in a consecutiveseries of adults who developed PJK.Methods:Consecutive cases of adultstreated for thoracolumbar deformity thatdeveloped PJK from the contributingauthors from 2004-2009 were identified.PJK was defined based on previouslypublished criteria. Clinical records werereviewed and standard radiographicmeasurements were performed.Results: 32 cases of PJK were identified(mean age 66 years, range: 46-80; 24women/8 men). 17 (53%) had surgeryprior to the index procedure. The mostcommon comorbidities includedosteopenia/osteoporosis (31%),hypothyroidism (31%), osteoarthritis(22%), and movement disorder (13%).The most common diagnosis for theindex procedure was degenerativescoliosis (n=26, 81%). The upper-mostinstrumented vertebrae were T4 (n=1),T10 or T11 (n=30), or L1 (n=1), and thelower-most instrumented levels were: L4(n=1), L5 (n=1), S1 (n=5), or ilium (n=25).Mean follow-up was 34 months. 16 (50%)required revision (mean of 1.7 revisions,range: 1-3) at a mean of 9.6 months(range: 0.7-40), and 16 (50%) did notrequire revision at last follow-up.Respective comparison of pre- and post-index surgery radiographic parametersshowed no significant change in sagittalbalance (9.6 vs. 8.0 cm, p=0.76), but therewas a significant increase of lumbarlordosis (24 vs. 42 degrees, p<0.001) andT5-T12 kyphosis (30 vs. 53 degrees,p<0.001) and reduction of pelvic tilt (29vs. 23 degrees, p=0.011).Conclusion:Collectively, these datasuggest that susceptibility to PJK mayrelate to development of an exaggeratedpostoperative compensatory thoracickyphosis to offset a significant, intendedsurgical correction of lumbar lordosis.The resulting inadequate maintenance ofsagittal balance, combined with theincreased kyphosis, may predispose todevelopment of PJK.

221Direct Vertebral Body Derotation: AComparison of Different TechniquesAmer F. Samdani, StevenWei-HungHwang,Michelle Marks, Tracey Bastrom, Randal Betz, Patrick CahillIntroduction: Pedicle screw fixation haspermitted the application of rotationalforces to assist in correcting the 3-Ddeformity of the scoliotic spine. Surgeons




may routinely apply a combination ofderotation techniques when correctingdeformity, but little is known of theimpact from each maneuver.Theoretically, unnecessary derotationmaneuvers may weaken the screw-boneinterface. We sought to compareoutcomes of various direct vertebral bodyderotation (DVBD) techniques as definedby inclinometer measures.Methods: A large, multicenter,prospective database was retrospectivelyqueried for patients with the diagnosis ofAIS who have undergone posterior spinalfusion with application of DVBDtechniques. All patients had at least 2years of follow-up, and those havingundergone thoracoplasty were excluded.Segmental derotation was defined ascorrective rotational forces applied to onevertebral level, whereas en-blocderotation referred to maneuversinvolving more than one level.Results: A total of 195 patients wereidentified. 104 patients underwentsegmental derotation, 20 had en-blocderotation performed, and 71 patientshad both. No significant radiographic orclinical differences existed between thegroups preoperatively or postoperatively.When subdivided into categories basedon the magnitude of preoperativeinclinometer measures (0-9 degrees, 10-15 degrees, and 16+ degrees), nosignificant difference in postoperativeinclinometer measures were identified(p=0.43 to 0.95) (Table 1).Conclusion:The use of varyingderotation techniques in the correction ofAIS deformity did not correlate with anydifference in outcomes based oninclinometer measures. The additionaluse of en-bloc derotation to segmentalmaneuvers does not provide any more ribprominence correction.

222Direct Vertebral Body Derotation,Thoracoplasty or Both: Which is Betterwith Respect to Inclinometer and SRS-22Scores?Amer F. Samdani, StevenWei-HungHwang,Peter Newton, Baron Lonner, Michelle Marks, Tracey Bastrom, Patrick Cahill, Randal Betz Introduction:Direct vertebral bodyderotation (DVBD) and thoracoplasty(Th) are powerful tools for correction ofrib deformities in patients with AIS. Weevaluated Th, DVBD, and both(Th/DVBD) with respect to postoperativeinclinometer readings and SRS scores todetermine which provides the bestcorrection of rib deformity and better

patient satisfaction.Methods: A prospective longitudinaldatabase was queried to identify AISpatients who underwent a posteriorspinal fusion with pedicle screws and 2years’ follow-up. 203 patients wereidentified grouped as follows: 1) Th alone(N=30), 2) DVBD alone (N=122), and 3)both Th/DVBD (N=51). Patients weresubdivided based on their preoperativeinclinometer reading: 1) = 9 degrees(mild), 2) 10-15 degrees (moderate), and3)=16 degrees (severe). Pre- andpostoperative inclinometer readings andSRS scores were compared using ANOVA.Results:Overall, the groups were similarpreoperatively except for the DVBD grouphaving higher percent thoracic flexibility.The preoperative rib deformity valueswere Th=13.2, DVBD=14.0, andTh/DVBD=12.9 (p=0.27). Takencollectively, the post-op 2 yearinclinometer readings were similar for allthree groups (Th=5.2, DVBD=7.0,Th/DVBD=5.6, P=0.66). However, theSRS-22 self-image scores weresignificantly better for patients havingboth Th/DVBD (Th=3.4, DVBD=3.4,Th/DVBD=3.8, P<0.01). When patientswere stratified by severity of pre-op ribdeformities, all with mild prominencesachieved similar corrections, althoughSRS self-image scores were highest in theTh/DVBD group. In patients withmoderate and severe preoperative ribprominences, the addition of Th wasnecessary for optimal rib deformitycorrection, but there was no difference inSRS-22 domains (Table 1).Conclusion:Our results suggest that Thalone, DVBD alone, or both provideequivalent inclinometer results inpatients with mild preoperative ribdeformities, but higher SRS-22 self-imagescores are achieved using both Th/DVBD.For more severe rib prominences (> 10degrees), better inclinometer readings areachieved with thoracoplasty, althoughSRS-22 self-image scores are comparable.

223Differences in Treatment and InpatientOutcomes for Hospitalized ScoliosisPatients in the United States from 1998to 2007Doniel Drazin, Miriam Nuno, Frank L. Acosta Introduction:Differences in access totreatment and outcomes have beendocumented in a variety of conditions inrecent years. This study evaluatespotential disparities in treatmentselection and outcomes for hospitalized

scoliosis patients. Patient- and hospital-specific factors were analyzed asindependent variables for predictingsurgical vs. non-surgical management ofthese patients, as well as for in-hospitalpatient outcomes.Methods:Using Nationwide InpatientSample (NIS) administrative 1998-2007data, we captured cases having a primarydiagnosis of scoliosis. Univariate andmultivariate analyses evaluated race,gender, socioeconomic factors, andhospital characteristics as predictors oftreatment (surgical vs. non-surgcial) andin-hospital outcomes (discharge,mortality, and complications).Results:The study analyzed 9522(surgical) and 2617 (non-surgical) cases.Univariate analysis showed both patient-and hospital-level variables as stronglyassociated with treatment selection andoutcomes. Concerning treatmentselection, multivariate analysis revealedAfrican-Americans and Hispanics as lesslikely to be treated surgically, whileCaucasians and private insurancepatients were more likely to undergosurgery (p<0.05). These differences intreatment selection for minoritiespersisted even when controlling forcomorbidities. Additionally, Caucasiansshowed a reduced risk of mortality,complications and adverse dischargecompared to African-Americans andHispanics (p=0.01). Large hospitals hadhigher surgical treatment rates than smallor medium-sized facilities as well as alower risk of mortality. Higherproportions of Caucasian patients wereadmitted to large teaching hospitals thanAfrican-American or Hispanic patients.Conclusion: Significant disparities werefound in the selection of operative vs.non-operative treatments, as well as inin-hospital morbidity and mortality forhospitalized scoliosis patients based onracial and socioeconomic variables. Thismay in part be due to differences inaccess to the resources of large teachinghospitals for different racial andsocioeconomic groups. Additionalreasons for these disparities, and theirimpact on quality-of-life measures andfuture health resource utilization forscoliosis patients requires additionalresearch.




224The Safety and Efficacy of TransforaminalLumbar Interbody Fusion for DeformityCorrection in Degenerative Scoliosis withSpinal StenosisAlan T. Villavicencio, Ewell Lee Nelson,Alexander Mason, Sharad, Frances A. Carr,Sigita Burneikiene Introduction:The utilization of a TLIF(Transforaminal Lumbar InterbodyFusion) approach for scoliosis offerspatients deformity correction without themorbidity associated with more invasivereconstructive surgeries. The purpose ofthis study was to analyze intra- andpostoperative complications associatedwith the TLIF surgical approach inpatients undergoing surgery for spinalstenosis and degenerative scoliosiscorrection.Methods:This study included a total of 29patients that underwent TLIF fordegenerative scoliosis with neurogenicclaudication and painful lumbardegenerative disc disease. TLIF surgerywas performed using a posterolateralpedicle screw construct. The averagefollow-up time was 27.4 months (range, 6 - 47).Results:The average age of patients was65.9 years (range, 49 83). TLIF procedureswere performed at 2.2 levels on average(range, 1 - 4) in addition to 7.0 (range, 3 - 11) levels of posterolateralfusion. The mean preoperative coronalCobb angle was 32.3 degrees (range, 15 - 55) compared to the mean of15.4 degrees (range, 1 - 49) postoperatively.The mean operative time was 8.8 hours (range, 4.6 - 15.1), EBL - 1091.7 mL (range,150-2500) and hospitalization time was8.0 days (range 3 - 28). Clinical outcomewas excellent/good in 17 (77%) ofpatients. The overall patient satisfactionrate was 77% (range, 42 - 100). Mean VASdecreased from 7.6 (range, 4 - 10)preoperatively to 3.6 (range, 0 -8)postoperatively. There was a total of 14(48.3%) hardware and/or surgicaltechnique related complications, 8(27.6%) of which required additionalsurgeries. The systematic complications(31%) included death (1),cardiopulmonary arrest withresuscitation (1), myocardial infarction(1), pneumonia (5) and pulmonaryembolism (1). A total of 5 patients (17.2%)had pseudoarthrosis.Conclusion:This study suggests that theTLIF approach is a feasible and effectiveapproach to treat degenerative adultscoliosis, but is still associated with a highrate of intra- and postoperativecomplications and a long recovery process.

225Biomechanical Analysis of Iliac Screwsvs. S2 Alar-Iliac ScrewsCyrus Wong, Chase Corn, Colin Crosby,Jesse Even, Gregory A. Mencio, Clinton J. Devin, Matthew J. McGirt Introduction:Current techniques ofpelvic fixation have been associated withhigh rates of lumbo-sacral pseudarthrosis,failure of fixation and hardwarecomplication. Hence, newer techniqueswere devised that allow for placement ofscrews into the ilium across thelumbosacral pivot point to improvebiomechanical stability. However, someof these techniques require additionalincisions and extensive soft-tissuedissection. This study describes andcompares the biomechanical strength oftwo techniques that provide low-profile,in-line fixation without the necessity ofadditional incisions or soft-tissuedissection.Methods: Embalmed cadavericspecimens (n=8, 4-male, 4-female) wereutilized. Anatomically-referenced iliacscrews and S2 alar-iliac screws measuring7.5mm by 80mm were placed in-situ onopposite sides of each specimen,alternating between right and left foreach type of fixation. Appropriateplacement of screws was confirmed withfluoroscopy and direct examination afterdissection of each pelvis. The pelvi werethen harvested, hemi-sectioned andpotted for biomechanical testing.Utilizing an MTS Bionix 858 Machine,screws were coaxially loaded at a rate of 5 mm/minute and pull out strength wasmeasured in Newtons.Results:Mean pull-out strength foranatomically-referenced iliac screws andS2 alar-iliac screws were 576 N (SD- 185)and 933 N (SD- 440), respectively. Astatistically significant higher pull-outstrength was noted in the S2 alar-iliacscrews as compared to standard iliacscrew (p<0.05).Conclusion: Iliac fixation is oftenperformed in a revision setting tosuccessfully achieve arthrodesis acrossthe lumbosacral junction. In this study,we demonstrate that utilizing an S2 alar-iliac fixation technique provides superiorpullout strength potentially avoidingthese complications and helping achievearthrodesis.

226Reduced Surgical Site Infections inPatients Undergoing Posterior SpinalStabilization of Traumatic Injuries UsingVancomycin PowderOwoicho Adogwa, Kevin O’Neill, Jason S. Smith, Amir Abtahi, Kristen Archer-Swygert, Clint Devin,Matthew J. McGirt Introduction:Despite improvementsthrough the use of prophylactic systemicantibiotics, surgical site infections remaina significant problem in the treatment oftraumatic spine injuries. Infection ratesas high as 10% have been reported in thispopulation. The impact on patients andcost of treating such infections isprofound. Local delivery of antibioticshas been found to be efficacious inanimal and human studies as an adjunctto systemic antibiotics in surgical siteinfection prophylaxis. We set out toevaluate the efficacy of using vancomycinpowder in surgical sites to preventinfections.Methods: Fifty-eight consecutive patientswith traumatic spine injuries treated withinstrumented posterior spine fusions at asingle academic center receivedintraoperative vancomycin powderapplied to their surgical site andprospectively followed for infection. Thispropsective cohort was compared to 60consecutive patients undergoingposterior fusion for trauma immediatelyprior to the prospective cohort. History ofprevious spine surgeries, substance use,diabetes, and body mass index werecompared. Incidence of infection was theprimary outcome evaluated.Results:The control (N=60) andtreatment groups (N=58) were statisticallysimilar, Table 1. There were no adversereactions to the vancomycin powder. Astatistically significant difference ininfection rate was found between thetreatment group (0%) and control group(12%, p=0.02), Table 2. No adverse effectswere noted from use of the vancomycinpowder.Conclusion:The use of vancomycinpowder in surgical wounds maysignificantly reduce the incidence ofinfection in patients with closedtraumatic spine injuries treated withinstrumented posterior spine fusion.Applying vancomycin powder to surgicalwounds is a promising means ofpreventing costly and harmfulpostoperative wound infections.




227Intraoperative Glucose Levels and itsAssociation with Developing PostoperativeSurgical Site Infections Following SpineSurgeriesFrances Mao, Ajit A. Krishnaney Introduction: Postoperative woundinfections following major surgicalprocedures continue to be a significantsource of morbidity and mortality in theUnited States. Current recommendationsfrom ICU and cardiac surgerymanagement indicate that aggressivemanagement of intraoperative glucoselevels result in lower rates of surgical siteinfections. This study is a retrospectivecohort analysis to determine theincidence of surgical site infectionsfollowing elevated intraoperative glucoselevels during spine surgeries.Methods: Peri-operative glucose levelsand infection control surveillance datawere analyzed for 2208 patients whounderwent cervical, thoracic, or lumbarspine surgical procedures at theCleveland Clinic Center for Spine Healthbetween March 2005 and March 2010.Results:Out of 2208 patients, 112 (5.1%)developed a surgical site infection duringthe 30-day postoperative period. Non-infected patients had a meanintraoperative glucose level of 132.11mg/dl (95% CI 130.72 - 133.5) comparedto infected patients with a meanintraoperative glucose level of 130.95mg/dl (95% CI 126.03 - 135.87 mg/dl. Anindependent two sample t-test found nosignificant difference in meanintraoperative glucose level betweenthese two groups (p = 0.6523). Univariatelogistic regression revealed a risk ratio perunit glucose of 1.00116 (95% CI 0.9953 -1.0075, p = 0.7081). Chi-square analysisfound no association between highglucose level (>110 mg/dl) and surgicalsite infection (chi-square value = 0.232, p= 0.6304). Follow-up analyses will berepeated to account for diabetes status.Conclusion:We did not find a significantassociation between elevatedintraoperative glucose levels and a higherincidence of postoperative surgical siteinfection. Our results add to previouscase-control studies exploring the sameassociation in neurosurgery. Because thecauses of surgical site infection are multi-factorial, the role of other peri-operativevariables in decreasing SSI incidenceshould be explored.

228Multiple-day Drainage when Using BMPfor Long Segment Thoraco-lumbarinstrumented Fusions Results in LowReoperation Rates for Infection andSeromaDwight Saulle, Kai-Ming G. Fu, Justin S. Smith, Christopher I. Shaffrey Introduction:Concerns over increasedinfection and seroma rates have beenraised when BMP is employed as an aidto fusion in spinal surgery. Few studieshave explicitly documented thesecomplications. In this study we evaluated87 consecutive patients undergoing longsegment thoracolumbar spinal fusionswith BMP to assess drain output and therates of reoperation for infection orseroma.Methods: Inclusion criteria included:patients undergoing 4 or more levels ofposterior instrumented thoracolumbarfusion, use of BMP for posterolateralarthodesis, age >18 years, and aperioperative followup of 60 days. 87consecutive cases from a singleinstitution were assessed. Typically, 21/8th inch hemovac drains were placed atsurgery and discontinued when twoconsecutive shifts (8 hrs) demonstratedless than 30cc of output. Drain output,length of time of drainage, and need forreoperation for wound seroma orinfection were retrospectively reviewed.Results:Mean age was 58.5 (SD 16.2,range 20- 81). Primary operativeindications were deformity, with 43patients undergoing revision surgery. Theaverage number of levels instrumentedand arthrodesed with BMP was 9.2 (SD3.7, range 4-18). The average dose of BMPwas 31.2 mg or 2.6 large sponges (SD9.6mg, range 12-48). Patients requireddrainage for a mean of 4.9 days (SD 1.3days, range 3-9 days). The average totaloutput was 1856cc (SD 787, range 530-4310cc). There were no significantdifferences between dose of BMP usedand amount or days of drainage (p=0.3and p=0.3, respectively). The woundinfection rate was 2.3% (2 cases, deepwound infection, required reoperation),and 2 (2.3%) sterile seroma occurred thatrequired reoperation for drainage. Noother wound complications were noted.Conclusion:Use of BMP for long-segment posterior thoracolumbar fusionsmay be associated with significant drainoutput, requiring multiple days ofdrainage. However, when drainedadequately, reoperations for infectionsand seromas occur infrequently

229Efficacy of Prophylactic PreoperativeInferior Vena Cava Filters for Major SpinalSurgery in Adults: A Review of 219Patients at a Single InstitutionJamal McClendon, Brian A. O’Shaughnessy,Timothy R. Smith, Patrick Alexander Sugrue, Ryan J. Halpin,Tyler R. Koski, Stephen L. Ondra Introduction:Venous thromboembolism(VTE) is a serious complication followingmajor spinal reconstructive surgery inadults. Specifically, pulmonary embolism(PE) can result in significant morbidityand mortality, and has been reported inup to 13% of patients. Placement ofprophylactic inferior vena cava filter(IVCf) was initiated as standard protocolfor all high-risk spine patients after a pilotstudy demonstrated decreased VTE-related morbidity and mortality.Methods: After IRB approval, medicalrecords of all patients receiving an IVCf ata single institution were reviewed. Age,sex, surgical approach, postoperativedeep vein thrombosis (DVT),postoperative superficial thrombus,presence of PE or paradoxical embolus,mortality, and IVCf complications werereviewed. Placement indicationsincluded history of DVT or PE,malignancy, hypercoagulability,prolonged immobilization, stagedprocedures > 5 levels, combinedanterior/posterior approaches, iliocavalmanipulation during exposure, andanesthesia > 8 hours. Descriptivestatistics were used for the analysis ofpatient characteristics. Non-parametric,frequency statistics (odds ratios, chi-square) were used for analysis of mainoutcomes.Results: 219 patients (150F, 69M) wereanalyzed with mean age of 58.8 years(range 17-86 years). There were twocomplications from IVCf placement (66Greenfield and 157 retrievable). Incidenceof lower extremity DVT was 18.7% in 36patients. PE incidence was 3.7% (8/219),and the paradoxical embolus rate was0.5% (1 patient). Prophylactic IVCf usereduced the odds of developing PE(OR=3.7, p<0.05) compared to populationcontrols. Mean follow-up was >2 years.Patients receiving Greenfield filters hadsignificantly higher VTE incidencecompared to those receiving retrievablefilters (OR=2.8, p=0.008). Anesthesiaduration longer than 8 hours significantlyincreases VTE incidence (p=0.029). Therewere 14 deaths, none related to PE orparadoxical embolus.Conclusion:VTE-related morbidity and




mortality have heightened the awarenesswithin the spine community to the peri-operative management of patientsreceiving major spinal reconstruction.Prophylactic IVCf placement significantlylowers PE rate.

230Defining the Role of Early SurgicalDecompression after Traumatic SpinalCord Injury: Results of a CanadianMulticenter StudyMichael G. Fehlings, Jefferson Wilson,Anoushka Singh, Catharine Craven, Henry Ahn, Brian Drew, Michael Ford Introduction: Although there existscompelling experimental evidencesupporting early spinal corddecompression after spinal cord injury(SCI), in practice, the role of surgeryremains controversial in the absence ofwell-designed clinical studies. We presentthe results of a multicenter Canadianeffort evaluating the impact of early vs.late surgical decompression post SCI onneurologic outcome, length of hospitalstay and development of complications.Methods: A prospective cohort study ofpatients within the Ontario Spinal CordInjury Rehabilitation (OSCIR) programwas performed. Eighty-six ASIA A-D SCIpatients, from six Ontario trauma centerswere enrolled between 2007 and 2009.Patient information was collectedpreoperatively, postoperatively, at acutecare discharge and at discharge fromrehabilitation. A grouped analysis wasperformed comparing the cohort ofpatients who received early surgery (<24hours after SCI) to those receiving latesurgery (=24 hours after SCI). Fisher’sexact test was used to examine fordifferences in baseline characteristics andoutcomes between early vs. delayedsurgery patients.Results: Of the 86 patients treatedsurgically there were 69 males and 17females, with a mean age of 46.3 years.There was a trend towards older age andincreased number of co-morbiditieswithin the late surgery group. Morepatients had a 2 grade or moreimprovement in their ASIA ImpairmentScore (AIS) from admission torehabilitation discharge in the earlysurgery group (p<0.05). Thisimprovement was most marked amongstthe early surgery ASIA A subgroup ascompared to injury matched patientswho underwent late surgery. Earlysurgery patients also experiencedsignificantly greater improvements inASIA sensory score over follow-up. Theonly significant predictor of acute care

and overall length of stay was theadmission AIS.Conclusion:The results of this studysupport the growing body of literaturewhich supports the principle of earlyintervention in the setting of spinaltrauma and SCI.

231Age Related Changes in NeurologicallyIntact Human Spinal Cords AssessedUsing Diffusion Tensor MR ImagingShekar N. Kurpad, Marjorie C. Wang,Michael Jirgis, Brian Schmit, John L. Ulmer,Brian Shender, Brian D. Stemper, Narayan Yoganandan, Allison HyngstromIntroduction: Diffusion Tensor MRImaging (DTI) is an important imagingmodality that can be useful formonitoring changes in tissue structure inthe brain and spinal cord. We present thelargest dataset of DTI derived indices inthe cervical spinal cord of a cohort ofnon-myelopathic individuals. The aim ofthis study was to characterize diffusioncharacteristics in the human cervicalspinal cord at various ages.Methods:With appropriate IRB approval,twenty-eight neurologically intact ageand sex matched subjects, 22 -85 yearsold, were enrolled in this study. A single-shot, twice-refocused, spin-echo,echoplanar pulse sequence was used toobtain axial images throughout thecervical segments of the spinal cord (C1 -C8) on a 1.5 Tesla Clinical MR imagingScanner in 45 minutes.Results: Diffusion images indicated asignificant decrease (p<0.05) in fractionalanisotropy (FA) and an increase in meandiffusivity (MD) after 65 years of age inboth male and female subjects. Cervicalmean diffusivity averaged 0.98+/- 0.03 x10(-3) mm(2)/s, fractional anisotropyaveraged 0.63+/- 0.02 mm(2)/s.Conclusion:To date, this is the largeststudy of DTI indices in a non-myelopathic population. This studyprovides evidence of changes in diffusioncharacteristics in the cervical spinal cordafter the age of 65 years. Changes inspinal cord diffusion with increasing agelikely reflect changes in spinal cord tissuestructure. We believe that the definition ofthe normative values of DTI indices inthese individuals will assist in evaluatingDTI index differences in patients withspinal cord disease in the future. Thesesignificant changes in diffusioncharacteristics should be accounted forwhen using DTI to diagnoseabnormalities in older patients.

232A Combined Neuroprotective Immuno-modulatory Therapy Mitigates EarlyBladder Dysfunction After ExperimentalSpinal Cord InjuryDaniel J. Hoh, John H. Shin, Megan Clark,Christopher A. Iannotti, Ran Harel, Nico van Rooijen, Hai-Hong Jiang, Margot Damaser, Michael P. Steinmetz Introduction:Traumatic spinal cordinjury (SCI) can result in devastatingmotor and sensory deficits. Of these,impaired bladder function is particularlysignificant as urinary tract complicationsrank among leading causes of morbidityand mortality in acute and chronic SCI.Experimental SCI in a rat contusionmodel demonstrates characteristicbladder dysfunction that parallels clinicalSCI including abnormal micturition,urinary retention, and pathologicchanges in functional bladder wallcompliance. Previously, our groupdemonstrated that a combined immuno-modulatory strategy of cAMP elevationand peripheral macrophage depletionimproves not only late but early hindlimbmotor function after SCI. In the presentstudy, we investigated the samecombined immuno-modulatory therapyto determine if it confers similarneuroprotective benefit in mitigatingearly bladder dysfunction after SCI.Methods: 12 rats were subjected to T8weight-drop contusion injury. Post-SCI,animals either were treated withcombined cAMP elevation + peripheralmacrophage depletion (treated=6) orwere untreated (control=6). Early bladderdysfunction was assessed using 2techniques. First, severity of urinaryretention was evaluated by measuringresidual urine volumes (RUV) after dailytimed manual bladder expression.Second, on post-SCI day 7, functionalbladder wall compliance was assessed bymeasuring bladder capacity atmicturition during transurethral singlecycle filling cystometry (0.125ml/min).Results: Animals had equivalent initialthoracic SCI (hindlimb BBB score<1,post-SCI day 1) with resulting abnormalmicturition. Control animals, however,demonstrated progressively increasingdaily RUV signifying worsening urinaryretention, whereas treated animals didnot (p<0.05)(Figure1). On post-SCI day 7,bladder capacity with filling cystometrywas significantly increased (p<0.01) incontrol (4.9±0.7ml) compared to treated(3.5±0.6ml) animals, signifying increaseddisturbance in functional bladder wallcompliance among control animals.




Conclusion: Experimental SCI results inearly bladder dysfunction characterizedby urinary retention and abnormalfunctional bladder wall compliance. Acombined immuno-modulatory strategyreduces these pathophysiologic findingsin acute experimental SCI. Clinicaltranslation of this therapy may decreaserisk of urinary complications in SCIpatients.

233The Role of Nitric Oxide in SecondarySpinal Cord Injury: Insights from a NewTransgenic ModelGeorge Al Shamy, Bettina Keller, Philippe Campeaux, Brendan Lee Introduction: Acute spinal cord injury(SCI) occurs worldwide with an annualincidence of 15-40 cases per million peryear. Recent advances have led to betterunderstanding of the pathophysiology ofSCI. Alterations in nitric oxide (NO), aneurotransmitter produced by Nitricoxide synthase from L-arginine have beenimplicated with different isoformsshowing distinct temporal patterns.Arginase negatively regulates NOproduction through competition withNOS for the substrate L-arginie. Our aimis to develop a transgenic mouse modelthat over-expresses arginase in distinctcell populations to understand their rolein NO production after SCI.Methods:We used standard techniques todevelop transgenic mouse models over-expressing the enzyme Arginaseexclusively in neurons as well as inastrocytes. Plasmids containing the genefor arginase were cloned under theneuronal specific thy1 promotor as wellas the Glial specific GFAP promotor.Transgenic founders were generated bypronuclear injections of the plasmids.Transgenic mice were identified at birthby eye pigmentation and confirmed byPCR using primers specific for Arginase.Western blot analysis, RNA extraction,enzyme essays as well as histology wereestablished in the transgenic models andcompared to control animals.Results:Our transgenic animals show anup to 30 fold over-expression of Arginasewith comparable enzyme activity.Arginine and citrulline levels are reducedin plasma of transgenic animals whencompared to wild type controls. Despitethese physiological discrepancies, ouranimals sustain normal growth. Undernonstressful conditions, these animalssurvive comparably to wild type litters,are fertile with offsprings born inmendelian ratio and have no histologicalabnormalities.

Conclusion:We were able to generateviable and fertile mice overexpressingArginase specifically in neurons and glialcells. These mice will be a valuable tool tounderstand the role different cells play inthe pathophysiology of acute spinal cordinjury.

234The Impact of Weekend HospitalAdmission on the Timing of Interventionand Outcomes After Surgery for AcuteSpinal Cord Injury in the United States,2005-2008Hormuzdiyar H. Dasenbrock, Timothy F. Witham, Daniel M. Sciubba,Ziya L. Gokaslan, Ali Bydon Introduction:Many studies havessuggested that patients who are admittedon the weekend have inferior outcomescompared to those admitted on aweekday. However, the impact ofweekend admission on the timing ofintervention and outcomes after surgeryfor acute spinal cord injury has not beenpreviously evaluated.Methods:Data from the nationalinpatient sample (2005-2008) wereretrospectively extracted. Patients wereincluded if they had a diagnosis of acutespinal cord injury, underwent spinaldecompression with or without fusionand were admitted emergently orurgently. Multivariable logistic regressionanalyses were conducted to calculate theodds of death, the development of apostoperative complication and theperformance of surgery on the day of orday after admission depending on if thehospital admission day was a weekend ora weekday. Logarithmic multivariateregression was used to evaluate theassociation of admission on a weekendwith length of stay and hospital charges.All analyses were adjusted for differencesin patient age, gender, co-morbidities,race, primary insurance, admission typeand hospital characteristics.Results: A total of 4,991 admissions wereevaluated, of which 35% were on theweekend. Weekend admission was notsignificantly associated with a higheradjusted odds of in-hospital mortality(OR: 1.00. 95% CI: 0.70. 1.44). Patientsadmitted on the weekend did not havesignificantly different adjusted odds ofperformance of surgery on the day of orday after surgery (OR: 0.91, 95% CI: 0.77,1.07). Postoperative complications,length of stay and total hospital chargeswere not significantly different betweenpatients admitted on the weekend or aweekday.Conclusion:Unlike other surgical

diseases, the outcomes of patientsadmitted in the United States for acutespinal cord injury during the weekend donot differ from those admitted during theweek. Nationwide, surgery is not delayedfor patients with acute spinal cord injurywho present on the weekend.

235Long-term Outcomes of Patients withMultilevel Ossification of the PosteriorLongitudinal Ligament after Laminectomy,Laminoplasty and Laminectomy andFusion: A Meta-Analysis of ObservationalStudiesHormuzdiyar H. Dasenbrock, Mohamad Bydon, Gayane Yenokyan,Timothy F. Witham, Ziya L. Gokaslan, Ali Bydon Introduction: Although posteriordecompression is preferred for multilevelcervical ossification of the posteriorlongitudinal ligament (OPLL), few studieshave evaluated the long-term outcomesof patients undergoing different posteriortechniques. We report a meta-analysis ofobservational studies comparing theimprovement in myelopathy and long-term complications including thedevelopment of postoperative kyphosis,the prevalence of axial pain and theprogression of OPLL in patients withmultilevel disease undergoinglaminectomy, laminoplasty andlaminectomy and fusion.Methods: A literature search wasperformed using MEDLINE of studiesindexed between January 1980 and June2010. Pre-determined study inclusioncriteria included reporting outcomes forpatients with OPLL separately from otheretiologies of myelopathy; studies wereexcluded if they reported a total of ten orfewer patients. Data on the severity ofmyelopathy (measured by the JapaneseOrthopedic Association (JOA) scale) andlong-term complications were extractedand pooled assuming random effects.Results: 40 studies with a total of 1,549patients were included of which 8reported laminectomy, 34 reportedlaminoplasty and 2 reportedlaminectomy and fusion. Among studieswith a long-term mean follow-up (of atleast four years), patients undergoinglaminectomy and fusion had a non-significantly higher recovery rate of JOAscore 62.5%, compared to 57.2% afterlaminoplasty and 53.4% afterlaminectomy. With an intermediate meanfollow-up (of at least two years), kyphosisdeveloped in 28.4% after laminectomy,7.5% after laminoplasty and 0% afterlaminectomy and fusion. Axial pain was




present in 35% of patients whounderwent laminoplasty; progression ofOPLL was noted in 70% afterlaminectomy and 66% after laminoplasty.Conclusion: Substantial long-termimprovement in myelopathy was seenregardless of the posterior techniqueutilized. However, long-termcomplications – particularly thedevelopment of kyphosis or neck painand progression of OPLL – were commonafter laminectomy or laminoplasty.Additional research is needed on thelong-term outcomes of patients withOPLL after laminctomy and fusion.

236Assessment of Potential Predictors ofLong-Term Outcomes of Surgery forCervical Spondylotic Myelopathy: Clinical,Demographics and MR imaging FactorsMichael G. Fehlings, Alina Karpova,Abhaya Vivek Kulkarni, Aileen Davis, Eric M. Massicotte Introduction:Cervical spondyloticmyelopathy (CSM) is the commonestcause of spinal cord dysfunctionworldwide, leading to severe neurologicalimpairments and major socio-economical costs. Nevertheless,prospective data on factors which predictsurgical outcomes are lacking.Methods: 65 consecutive patients withCSM were treated at a university-basedcenter. After excluding 4 patients whowere lost to follow-up, 61 (follow-up:94%) were analyzed for prediction ofsurgical outcomes. There were 42 malesand 19 females with mean age of 57 years(range: 32 to 86 years). The mean mJOAscore improved from 12.8 ± 2.7 pointspreoperatively to 15.8 ± 2.3 points at 12months postoperatively (p<0.0001). Themodified Japanese OrthopaedicAssociation Scale (mJOA) was used as theprimary outcome measure to quantifyfunctional disability at admission and at12-months follow-up. Potentialpredictors of functional outcomesincluded age, gender, duration ofsymptoms, severity of myelopathy,number of compressed segments, antero-posterior diameter [AP] and transversearea [TA] of the spinal cord at the site ofmaximal compression, three patterns ofMRI spinal cord signal intensity changes.Data were analyzed using Spearman’srank correlation test, ANOVA and Mann-Whitney test, and stepwise multivariableregression.Results:Higher baseline mJOA scoreswere associated with younger age(p=0.0002), shorter duration of symptoms(p=0.03), fewer compressed segments

(p=0.04) and less severe cordcompression (p=0.02). Moreover, betterpostoperative mJOA scores wereassociated with younger age (p<0.0001)and shorter duration of symptoms(p=0.07). Using multivariate analysis,baseline and follow-up mJOA scores werebest predicted by age.Conclusion:The data suggest thatfunctional outcomes can be predicted byage and baseline mJOA scores. Moreover,age negatively affects functionaloutcomes following surgical treatment.

237The AOSpine North America CervicalSpondylotic Myelopathy Study:Perioperative Complication RatesAssociated with Surgical Treatment Basedon a Prospective Multicenter Study of302 PatientsJustin S. Smith, Christopher I. Shaffrey,Branko Kopjar, Paul M. Arnold, Sangwook Yoon, Alexander R. Vaccaro,Darrel S. Brodke, Michael Janssen, Jens Chapman, Rick Sasso, Eric J. Woodard, Robert J. Banco, Eric M. Massicotte, Mark B. Dekutoski,Ziya L. Gokaslan, Christopher Bono,Michael G. Fehlings Introduction:Cervical spondyloticmyelopathy (CSM) often warrantssurgical treatment. Our objective was toassess complication rates associated withthe surgical treatment of CSM based on aprospective multicenter study.Methods:The AOSpine North AmericaCSM study is a recently completedprospective multicenter study of patientssurgically treated for CSM. Standardizedforms were used to collect clinical andsurgical data. Perioperative complicationrates (within 30 days of surgery) wereassessed.Results: A total of 302 patients (178men/124 women) were enrolled, with amean age of 57 years (range: 29-86).Surgical approaches included anterior-only (n=176, 58%), posterior-only (n=107,35%), and combined anterior-posterior(n=19, 6%). Fusion, laminoplasty, andcorpectomy were performed in 27%, 13%,and 18% of cases, respectively. Of 332reported adverse events, 73 wereadjudicated to be complications,including 25 major (8%) and 48 minor(16%). The most common complicationsincluded: cardiopulmonary events(3.3%), infection (7 superficial/2 deep,overall 3.0%), dysphagia (3.0%), C5radiculopathy/palsy (1.7%), worsenedmyelopathy (1.3%), new radiculopathyother than C5 (1.0%), epidural/woundhematoma (1.0%), instrumentation

malposition/migration (1.0%), durotomy(1.0%), other neurological deficit (0.7%),renal complications (0.7%), and alteredmental status (0.7%). Single cases ofdeath, stroke, re-operation (not otherwisespecified), thromboembolism, wounddehiscence, worsened neck pain, andpneumonia were reported. Tenmiscellaneous complications weredocumented.Conclusion:These data providebenchmark rates for perioperativecomplications associated with thetreatment of CSM and demonstrate aremarkably low rate of neurologicalcomplications, with the vast majoritycomplications being treatable andwithout long-term impact.

238Spinal Injuries in Children andAdolescentsJan Stulik, Jan Kryl, Michal Barna, Petr Nesnidal Introduction: In this retrospective study,the effectiveness of conservative andsurgical treatment of injured spines inchildren is evaluated in a 10-year period.Methods: All patients from birth to thecompleted 18th year of age treated in ourdepartments between 1996 and 2005were included in this study. The patients,evaluated in three age categories (0-9, 10-14, 15-18), were allocated to two groupsaccording to the treatment used.Results:During 1996 through 2005, wetreated a total of 15 646 patients withinjury to the skeleton, aged 0 to 18 years.The spine was affected in 571 cases,which is 3.6%. We used conservativetreatment in 528 (92.5%) and surgery in43 (7.5%) children. The group of patientstreated conservatively consisted of 292boys (55.3%) and 236 girls (44.7%); 219(41.5%) were in the 0-9 year category, 251(47.5%) were between 10 and 14 years oldand 58 (11 %) were 15 to 18 years old. Inall age categories, injury to the thoracicspine was most frequent (340; 64.4%).Multi-segment injury in 124 patients(23.5%). The thoracolumbar spine wasaffected in 22 patients (4.2%), and lumbarvertebrae in 28 patients (5.3%), uppercervical spine in 4 (0.8%) and lowercervical spine in 10 (1.9 %) patients. Noneof the patients showed neurologicaldeficit. The surgically treated groupincluded 29 (67.4%) boys and 14 (32.6%)girls; two (4.7%) children were between 0and 9 years, nine (20.9%) between 10 and14 years, and 32 (74.7%) between 15 and18 years. The upper cervical spine wasoperated on in 5 (11.6%), lower cervicalspine in 8 (18.6%), thoracic spine in 13




(30.2%), thoracolumbar spine in 5(11.6%) and lumbar vertebrae in 12(27.9%) patients. Neurological deficit wasrecorded in 9 (20.9%) patients.Conclusion:Childhood spinal injuriesaccount for only 2 to 5% of all spinalinjuries and for 3.6% of all skeletalinjuries in children. Conservativetreatment is preferred; surgery before 12years of age is strictly individual, whileafter 12 years therapy is similar to thatused in adults.

239Diffusion Tensor MR Imaging in Rats withVarying Spinal Contusion SeverityShekar N. Kurpad, Brian Schmit, Michael Jirjis, Mohammed Ali Jazayeri,John L. Ulmer Introduction:Diffusion Tensor Imaging(DTI) is a promising novel MRI basedtechnique for spinal cord tractography.We have previously shown that DTIderived indices, including meandiffusivity (MD), fractional anisotropy(FA), lateral and transverse apparentdiffusion coefficients (lADC and tADC)correlate with structural and functionalchanges after SCI in the zone of injury. Wepresent the preliminary results of ourrecent investigations in the validation ofDTI FA as a biomarker for distal changesin the cervical spinal cord afterexperimental thoracic injuries of varyingseverity.Methods: Four groups of rats were usedfor the experiments. These includedanimals with sham surgery, mild,moderate and severe thoracic injuriesderived from a standard NYU impactor.Animals were imaged in vivo using a 9.4Tmagnet, and axial diffusion weightedimages were collected at a b-value of 500seconds/mm(2). Average FA values werecalculated in axial sections of the cervicalspinal cord with five slices representingC2-3/C3-4/C4-5/C5-6 and C6-7respectively.Results: In all three injury groups, averageFA values showed a progressivedecreasing trend in a caudal cephaladdirection ranging from 0.69 to 0.59mm(2)/s in FA. Severely injured ratsshowed the greatest reduction in FAvalues (average of 0.9 decrease in FA) withmoderate and mild injured animalsshowing slightly lesser reduction (averageof 0.6 and 0.4 mm(2)/s decrease in FArespectively). FA values in the severeinjury group were significantly different(analysis of variance [ANOVA], p > 0.05)than the other two groups. No significantdifference was observed between themild and moderate groups.

Conclusion:We have demonstrated thatFA can be a reliable biomarker forestimating spinal cord structural changesin the cervical spinal cord after thoracicinjury. In addition, our studies show thatFA changes in the cervical cord can reflectinjury severity in the thoracic cord. Theseobservation carry important implicationsin further refining DTI indices to assessSCI severity.

240CTA Screening for Vertebral Artery Injuryin Transverse Foramen Fractures in 320PatientsSanjay S. Dhall, Albert Jesse Schuette, Jack Barrow, Gerald E. Rodts, Jr., Daniel L. BarrowIntroduction:Transverse foramenfractures are a common finding aftercervical spine trauma. Computedtomography angiography (CTA) is a rapidmethod to screen for vertebral arteryinjury in patients who sustain thesefractures.Methods:We reviewed the prospectivetrauma database of 2084 consecutivecervical spine fractures from 2000 to2009. We identified 320 patients withtransverse foramen fractures andcomputed tomography angiography. Theprimary goal is to identify the incidenceof vertebral artery injury in this blunttrauma population.Results:CTA results were obtained on all320 patients with cervical transverseforamen fractures. In this population,19% of patients were found to havesustained vertebral artery injury on CTA.Conclusion:Transverse foramen fracturesof the cervical spine should undergoscreening with CTA to evaluate forvertebral artery injury. Fracture patternsassociated with vascular injury will bediscussed. Outcomes of varioustreatment methods employed will bediscussed.

241Dens Fractures in Patients over 65 Yearsof Age: Anterior Screw Fixation of theDens vs. Posterior Fixation of C1-C2Jan Stulik, Jan Kryl, Petr Nesnidal Introduction:This study is a retrospectiveevaluation of dens fractures in patientsover 65 years of age treated with anteriorscrew fixation of the dens (ASF) orposterior atlantoaxial fixation and fusion(PF).Methods:We treated surgically 28patients older then 65 years with densfractures, with a mean age of 77.4 years(65-90 years). According to the type oftreatment the whole cohort was divided

into 2 groups that were subdivided intotwo age groups of patients 65-74 years old(N=8, mean age 68.5) and older then 75years (N=20, mean age 81). Neurologicaldeficits were found in three patients,Frankel D type. All patients underwentradiograph examination in twoprojections, CT scans and in most casesalso MRI examination. Based on theseexaminations, the type of injury wasdetermined and method of treatmentindicated. Follow-up was 12 to 78 monthsafter the surgery (mean 31.3 months)with consideration on aetiology and typeof injury, neurological finding, method oftreatment, union of the fracture lines orC1-C2 fusion, stability of the spine andthe final outcome.Results:There was statistically significantdifference in the mortality (p<0.05), with0% in the younger group and 40% in theolder group. Mortality within 6 weeksafter the injury was 28.6%. Mortality afterASF was 21.4% and mortality after PF was35.7% (p>0.05). Of the 20 survivingpatients, 11 were treated with ASF and 9with PF. We found only one case ofnonunion of the dens (9.1%) and onefibrous callus in the region of C1-C2fusion and the fracture line in the dens(11.1%) (p>0.05).Conclusion: Active surgical treatmentconduces the improvement of the qualityof life of elderly patients after densfractures. Mortality is influenced by theage rather than by the surgical techniqueused. Elderly patients with a neurologicaldeficit mostly die of associated diseases.

242A Pilot Evaluation of the Role of Bracingin Stable Thoracolumbar Burst FracturesMohammed F. Shamji, Darren Roffey, Don Chow, Joseph O’Neil, Garth Johnson,Daryl Young, Eugene WaiIntroduction:The management ofthoracolumbar burst fractures maydepend on clinical presentation ofneurological deficit as well asradiographic features of fracture severitysuggestive of instability.[1] When patientsare neurologically intact and have milddeformity on computed tomography(CT), conservative therapy may beapplied, conventionally involving bracingover months to permit fracturestabilization.[2,3] We investigated theutility of bracing vs. no bracing amongstable thoracolumbar burst fractures.Methods: Patients with stablethoracolumbar burst fractures, singlelevel between T12 and L2, withoutneurological deficit or lower extremityinjury were entered into this study.




Randomization was computer-generatedin sealed envelopes. Investigatedendpoints were at time of presentationand at 6-months follow-up and includedradiographic outcomes of kyphoticprogression and loss of vertebral heightand clinical outcomes of self-reportedpain and disability. Continuous variableswere analyzed by two-factor ANOVA(time and treatment as factors), at the0.05 level of significance.Results:There were no differencesbetween patients treated with or withoutbracing regarding the level of injury(p=0.18) and initial spine geometryincluding extent of fragment retropulsion(p=0.97), anterior loss of height (p=0.56),or Cobb angle (p=0.26). Progressive lossof height occurred to by additional 17±4%in both groups (p=0.96) and degree ofkyphotic progression was also nodifferent by treatment (brace 6±2, nobrace 8±2, p=0.59). Improvements in self-reported pain and disability wereobserved in both treatment groups, tosimilar extent regardless of managementarm (Figure 1, p=0.40).Conclusion: Patients with stablethoracolumbar burst fractures treatedwith or without bracing had similaroutcomes at 6 months. Radiographicoutcomes of fracture geometry andclinical outcomes of pain and disabilityscores were no different by treatmenttype. These patients may benefit fromconservative therapy simply involvingsequential imaging without braceimmobilization, although larger series ofpatients may be required.

243Clinical Outcome and Risk of Reoperationfor Recurrent TCS in 99 ConsecutiveChildren Operated for Tight or Fatty FilumLauren Rose Ostling, Karin S. Bierbrauer,Charles Kuntz Introduction: For operative division of atight or fatty filum in pediatric patients,the clinical outcome is often assumed tobe favorable, while complications andrisk of reoperation for recurrent tetheredcord syndrome (TCS) are frequentlyconsidered negligible.Methods: In this retrospective study, theauthors reviewed the medical records of99 consecutive children who underwentinitial division of the filum terminale atCincinnati Children’s Hospital MedicalCenter (November 1995 - May 2006) for atight or fatty filum. Presentingsymptoms/signs, MRI findings,complications, postoperativesymptoms/signs, and need forreoperation were recorded. Mean follow-

up for all patients was 32 months; 79 werefollowed for greater than or equal to 6months and 67 were followed for greaterthan or equal to 12 months.Results:The most common presentingsymptoms were bladder and/or boweldysfunction, followed by gaitabnormality, back pain, and spasticity. Atlast follow-up, 86 patients were improvedor stable, while 11 patients had at leastone symptom/sign which had worsened.There were a total of 12 complications in9 patients including 5 wound infections, 4CSF leaks, 1 pseudomeningocele, 1 stitchabscess and 1 transient headache. Fivechildren underwent a reoperation forrecurrent TCS with further detethering ofthe spinal cord. Worsening back pain wasthe most common symptom in thosepatients requiring reoperation. Meantime to reoperation was 58 months (range22 - 73 months). Arachnoid adhesionswere found to have accounted for theretethering at the time of reoperation infour of the five patients.Conclusion:Division of a tight or fattyfilum, in this consecutive series ofpediatric patients, resulted in improvedor stable symptoms in 89% of patients.However, the complication rate and 5.1%rate of reoperation for recurrent TCS arenot insignificant.

244Determination of the MinimumImprovement in Pain, Disability, andHealth State Associated with Cost-effectiveness: Introduction of the Conceptof Minimum Cost Effective Difference(MCED)Scott Parker, Owoicho Adogwa, Brandon J. Davis, Clint Devin, Matthew J. McGirt Introduction: Spinal surgical outcomestudies rely on patient-reported-outcomes (PRO) to assess effect. Ashortcoming of these outcome-metrics isthat extent of change in numerical scoreslack a direct meaning or clinicalsignificance. Hence, the concept ofminimum clinical important difference(MCID) was adopted as smallestimprovement in PRO needed to achievetreatment-effectiveness. While total costof <$50,000 per QALY-gained isconsidered cost-effective for a particulartreatment, a measure for smallestimprovement in PRO that is associatedwith cost effectiveness has yet to beintroduced. Here we utilize a commonMCID-calculation method with a cost-utility threshold-anchor to introduce theconcept of minimum cost effectivedifference (MCED).

Methods: Forty-five patients undergoingtrans-foraminal lumbar interbody fusion(TLIF) for degenerative spondylolithesiswere included. BP-VAS, LP-VAS, ODI, EQ-5D were administered before and 2-yearspostoperatively. Cost was calculated fromResource use x Medicare nationalallowable payment amounts (direct cost)and Missed work x self-reported gross-of-tax wage rate (indirect cost). Total cost perQALY gained was assessed for eachpatient. The MCED for each PRO wasdetermined using receiver operatingcharacteristic (ROC) curve analysis with<$50,000/QALY as cost-effective anchorand MCID determined with the healthtransition index (HTI) of the Short Form-36 as anchor.Results: A significant improvement in alloutcome measures was observed twoyears after TLIF(Figure 1), with a meantwo-year gain of 0.86 QALYs per patient.Cost was <$50,000/QALY gained for 27(60%) patients. MCED was greater thanMCID for each PRO: 3.1 vs. 2.1 for VAS-LP,3.1 vs. 2.1 for VAS-BP, 19 vs. 14 for ODI,and 0.32 vs. 0.15 for EQ-5D,Table 1. ForMCED, area under the ROC curve rangedfrom 0.78-0.98, suggesting the four PROchange scores were accurate predictors ofcost-effectiveness. Mean cost per QALY-gained was lower for patients achievingvs. not-achieving MCED in VAS-LP($43,560 vs. $112,087), VAS-BP ($41,280vs. $129,440), ODI ($30,954 vs. $121,750),and EQ-5D ($35,800 vs. $189,412).Conclusion:Minimum cost effectivedifference serves as the smallestimprovement in outcome metric thatrepresents a cost-effective response tosurgery. The extent of improvementassociated with cost-effectiveness wasconsistently greater than that associatedwith patient-reported clinicaleffectiveness (MCID). MCED followingTLIF is 3.1 points for BP-VAS, 3.1 pointsfor LP-VAS, 19 points for ODI, and 0.32QALYs for EQ-5D.

245Comparative Effectiveness of MinimallyInvasive vs. Open Transforaminal LumbarInterbody Fusion: Two-year Assessment ofNarcotic Use, Return to Work, Disability,and Quality of LifeOwoicho Adogwa, Scott Parker, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirt Introduction:Minimally invasivetransforaminal lumbar inter-body fusion(MIS-TLIF) for lumbar spondylolithesistheoretically allows for surgical treatmentof back and leg pain while minimizingblood loss and tissue injury. While prior




studies have demonstrated shorterhospital stay and equivocal six andtwenty-four month outcomes with MIS-vs. open-TLIF, the effect of MIStechniques on postoperative narcotic useand return to work are poorlyunderstood.Methods: Forty patients undergoing MIS-TLIF (n=20) or open-TLIF (n=20) forgrade I degenerative spondylolithesis-associated back and leg pain wereenrolled. Two-year outcomes wereprospectively assessed via phoneinterview and included pain [visualanalogue scale (VAS)], low-back disability[Oswestry disability index (ODI)], qualityof life [EuroQol (EQ-5D)], occupationaldisability, and narcotic use.Results:MIS vs. open-TLIF cohorts weresimilar at baseline. Median [IQR] lengthof hospitalization following surgery wassignificantly less for MIS- vs. open-TLIF(3 [3-3] vs. 5.5 [4-6] days), p=0.001. MIS-vs. open-TLIF patients demonstratedsimilar two-year improvement in VAS-BP,VAS-LP, ODI, and EQ-5D scores, Figure3.Overall, median [IQR] length ofpostoperative narcotic use was 3.0 [1.4-4.6] weeks and significantly shorter forMIS- vs. open-TLIF patients (2.0 [1.0-3.0]vs. 4.0 [1.4-4.6] weeks, p=0.008),Figure 1.Overall, median [IQR] time to return towork was 13.9 [2.2-25.5] weeks andsignificantly shorter for MIS- vs. open-TLIF patients (8.5[4.4-21.4] vs. 17.1[1.8-35.9] weeks, p=0.02), Figure 2.Conclusion: Both minimally invasive andopen-TLIF provide long-termimprovement in pain, disability, andquality of life in patients with back andleg pain from grade I degenerativespondylolithesis. However, MIS-TLIF mayallow for shortened hospital stays,reduced postoperative narcotic use, andaccelerated return to work, influencingfactors associated with direct medicalcosts and indirect costs of lost workproductivity.

246Comparative Analysis of Surgical SiteInfection after Minimally Invasive vs.Open Posterior/Transforaminal LumbarInterbody Fusion: Analysis of HospitalBilling and Discharge Data from 5,328PatientsMatthew J. McGirt, Scott Parker, Jason Lerner, Luella Engelhart, Michael Y. Wang Introduction: Surgical site infection (SSI)following posterior or transforaminalinterbody fusion (P/TLIF) of the lumbarspine is associated with significantmorbidity and medical resource

utilization. To date, there have been nostudies conducted with sufficient powerto compare the incidence of SSI followingminimally invasive (MIS) vs. open P/TLIFprocedures. We assess the incidence anddirect costs of SSI in patients undergoingMIS vs. open P/TLIF from a hospital-system database representing more than600 hospitals and 5 million discharges peryear.Methods: In a retrospective longitudinalanalysis of hospital discharge and billingrecords from the Premier Perspective™database, all patients undergoing P/TLIFwere identified via InternationalClassification, 9th Revision, ClinicalModification (ICD-9-CM) procedurecodes. MIS procedures were identified byinstrumentation trade name. SSI wasdefined as a subsequent diagnosis ofpostoperative infection or administrationof intravenous antibiotics 1-8 weekspostoperatively. Medicarereimbursement rates and commercialpayer charge data were used to estimatethe direct medical costs of SSI.Results: 3,793 patients underwent openP/TLIF (1,625 one-level, 2,168 two-level)and 1,535 patients MIS-P/TLIF (882 one-level, 653 two-level). Overall, MIS- vsopen-P/TLIF was associated with areduction in SSI [71 (4.6%) vs 228 (6%),p=0.047], Table 1. Stratified by levelsfused, SSI was similar for one-levelP/TLIF [41 (4.6%) vs 77 (4.7%), p=0.919],but significantly reduced for two-levelMIS-P/TLIF [30 (4.6%) vs. 151 (7.0%),p=0.030], Table 2. The estimated cost ofsurgically managed SSI was $23,380 andmedically managed SSI $12,419. For two-level fusion, estimated SSI-associatedcost per 100 P/TLIFs performed was$115,959 for open- and $72,306 for MIS-P/TLIF (cost savings: $43,653 per 100two-level P/TLIFs performed).Conclusion:This population-based studyof data from over 600 hospitals in the USindicates that MIS- vs. open-P/TLIF wasassociated with a decreased incidence ofpostoperative infections after two-levellumbar fusion. Considering the morbidityand costs associated with SSIs, MIS-lumbar fusion may be a valuable tool inreducing hospital infection rates andcosts associated with spine care.

247Endoscopic Image-Guided TranscervicalOdontoidecomy: Long-Term Outcomes of15 Patients with Basilar InvaginationHormuzdiyar H. Dasenbrock, Michelle J. Clarke, Ali Bydon, Daniel M. Sciubba, Timothy F. Witham,Ziya L. Gokaslan, Jean-Paul Wolinsky

Introduction:Ventral decompressionwith posterior stabilization is thepreferred treatment for symptomaticirreducible basilar invagination (BI).However, the standard (and expansile)transoral approaches to the dens can beassociated with substantial morbidity.Endoscopic image-guided transcervicalodontoidectomy (ETO) may allow fordecompression to be performed with lessmorbidity. We report the largest serieswith the longest follow-up of patientsundergoing odontoidectomy for BI via anendoscopic transcervical approach.Methods: 15 patients who had a follow-up of at least 9 months wereretrospectively reviewed. Intraoperatively,the vertebral body of C2 was removedand the odontoid was resected in a “top-down” manner using endoscopicvisualization and frameless stereotacticnavigation. Posterior instrumentedstabilization was subsequentlyperformed.Results:The average (± standarddeviation) age of the patients was42.6±24.5 (range 11-72) years; the meanpreoperative degree of basilarinvagination (measured above theMcGregor line) was 12.0±9.9 (range 0-35)mm. Postoperative complicationsoccurred in 6 patients, including aurinary tract infection (n=2), upperairway swelling (n=2), dysphagia (n=2),gastrostomy tube placement (n=1) andan asymptomatic pseudomeningocele(n=1). The average length of hospital staywas 9.1±4.9 (range 2-23) days. With amean follow-up of 34.9±14.4 months,myelopathy improved in all patients andthe mean modified Japanese OrthopedicAssociation (mJOA) score increased from11.1±4.0 to 16.0±1.4 (p=0.0001). Patientswith a diagnosis other than rheumatoidarthritis (p=0.003) or who a higherpreoperative mJOA score (p=0.026) weresignificantly more likely to have acomplete neurological recovery;improvement in neurological functionwas not significantly associated withpreoperative severity of basilarinvagination. At the final follow-up, allpatients had evidence of solid arthrodesisand resolution of their pre- orpostoperative dysphagia. No patientsexperienced late neurologicdeterioration.Conclusion: ETO may be a validtreatment for patients with symptomaticirreducible basilar invagination thatavoids some of the morbidity of transoralsurgery and leads to long-termimprovement in myelopathy.




248Minimally Invasive Treatment of AdjacentSegment Degeneration via XLIFJody A. Rodgers, W.B. Rodgers, Edward J. GerberIntroduction:The XLIF approachprovides a minimally disruptivealternative to anterior column access thatallows for large graft placement, diskheight restoration, and indirectdecompression, while avoiding posteriorscar tissue from the previous procedure.Results of ASD treated with XLIF arepresented.Methods:Of our single-site consecutiveseries of 932 XLIF patients, 276 weretreated for ASD. Clinical and radiographicmeasures were prospectively collectedand evaluated.Results: Age ranged from 29-91 years(average 61.6 years). 90.6% had one ormore comorbidity. 144 patients (52%)were obese or morbidly obese. All but onecase included supplemental fixation: 47%unilateral pedicle screws, 4% bilateralpedicle screws, 12% lateral embroideredplate, and 43% laterally tabbed interbodyimplant. In 15 cases with prior posteriorinstrumentation, the pre-existing rodswere removed unilaterally and revised onthat side; in all other cases with priorinstrumentation, adjunctive lateralfixation was used. Hospital stay averaged1.3 days, with 2 blood transfusions andone wound infection. Complicationsincluded intraoperative hardware failure(4, revised during same procedure withno incident), ileus (5), gallstonepancreatitis (1), urinary retention (3),kidney stone (1), peritoneal catheterocclusion (1), pulmonary embolism (1),subcutaneous hematoma (1), delirium(1), atrial fibrillation (3), MI at 6 weekspost-op (1), compression fracture at anadjacent level (5), sacral fracture (1), andpostoperative quadriceps weakness (1,resolved within 4 weeks of surgery).Average VAS scores improved by 4.6points from pre-op to 12 months. Averagedisk height improved from 6.4 to 10.6 atpost-op, settling to 8.7mm at 24 months;slip from 3.5 to 0.6mm. Definitive signs offusion (Lenke 1-2) were present in 74% at3 months, 91% at 6 months, 96% at 12months and 95% at 24 months.Conclusion:Our experience using XLIF inthe ASD population has shown thatclinical and radiographic indicatorsimprove commensurately and the overalloutcome is encouraging.

249Comparative Clinical Outcomes FollowingMinimally Invasive L5-S1 InterbodyFusion, Comparison of TLIF, ALIF, andAxiaLif for Single-level ArthrodesisZachary Adam Smith, Larry T. Khoo Introduction:The development of newminimally invasive spine (MIS)techniques for lumbosacral fusion hasprovided the spine surgeon multiplemethods for fusion at the L5-S1 interbodyspace. The authors compare clinical andradiographic outcomes from a cohort ofprospectively followed patients treatedwith three modern techniques, MIS-TLIF,ALIF, and AxiaLIF.Methods: Between June 2003 and January2009, 58 patients were treated for isolateddegenerative disk disease of the L5-S1segment. All patients presented with backpain with or without radiculopathy andhad failed conservative management. Theaverage patient age was 43.34 years.Twenty patients were treated with TLIF, 19with ALIF, and 19 with AxiaLIF. Allpatients were prospectively followed withpre- and postoperative visual analogscore (VAS) and Oswestry-DisabilityIndex (ODI) scores as well as routineradiographic follow-up.Results:Clinical outcome with ODIdemonstrated a decrease in ODI of -25with TLIF, -22 with ALIF, and -24 withAxiaLIF. VAS leg scores decrease 92% inpatients treated with TLIF, 76% with ALIFand 71% with AxiaLIF. The time of accessto the interbody space was most rapidwith AxiaLIF (65m) and slightly longerwith ALIF (85m) and TLIF (105m).Radiographic outcomes showed that ALIFproduced the best distraction of theinterbody space (8.6mm); TLIF (6.3mm),AxiaLIF (5.9mm). Fusion with TLIF andALIF was 95% and AxiaLIF 90%.Subsidence was greatest with AxiaLIF16% followed by TLIF (12%) and ALIF(9%). Complications included 2 patientswith radiculitis following TLIF. There wasa single CSF leak (TLIF) and a singlelumbar plexus injury (ALIF). There was asingle vascular injury (ALIF) and a singlevisceral injury (AxiaLIF).Conclusion:MIS-TLIF, ALIF, and AxiaLIFare all modern, MIS-type approaches tothe L5-S1 interbody space. Patientoutcomes suggest each has uniqueclinical strengths and specificdisadvantages. Complications with eachapproach is unique and primarily relatedto anatomy of the access route.

250Cost-utility Analysis of Minimally Invasivevs. Open Multilevel Decompression forLumbar StenosisOwoicho Adogwa, Brandon J. Davis, Erin Fulchiero, Oran Aaronson, Joseph S. Cheng, Clint Devin, Matthew J. McGirt Introduction:Minimally invasive (MIS)multi-level hemilaminectomy fordegenerative lumbar spinal stenosisallows for effective treatment of back andleg pain while theoretically minimizingblood loss, tissue injury, andpostoperative recovery. No studies to datehave evaluated the comprehensivehealthcare costs associated withmultilevel laminectomy procedures, norassessed the cost-effectiveness of MIS vs.openmultilevel laminectomy.Methods: Fifty-four patients undergoingMIS paramedian tubular (n=27) or openmultilevel hemilaminectomy (n=27) forlumbar stenosis associated radiculopathywere prospectively studied. Total back-related medical resource utilization,missed work, and health-state values(quality adjusted life years (QALYs),calculated from EQ-5D with U.S.valuation) were assessed after two-yearfollow-up. Two-year resource use wasmultiplied by unit costs based onMedicare national allowable paymentamounts (direct cost) and work-daylosses were multiplied by the self-reported gross-of-tax wage rate (indirectcost). Difference in mean total cost perQALY gained for MIS- vs. open-laminectomy was assessed asincremental cost-effectiveness ratio(ICER: COSTmis - COSTopen/QALYmis -QALYopen).Results:MIS vs. open cohorts weresimilar at baseline, Table 1. Both MIS andopen laminectomy were associated with atwo-year gain of 0.72 QALYs, Figure 1.Mean direct medical costs ($13,334 vs.$14,291), indirect societal costs ($9,775 vs.$11,130), and total two-year cost ($23,109vs. $25,420, p=0.21) were similar betweenMIS- and open-hemilaminectomy, Table2. MIS was associated with similar totalcosts and utility, making it a costequivalent technology compared to thetraditional open approach.Conclusion:MIS- vs. open- multilevelhemilaminectomy was associated withsimilar cost over two years whileproviding equivalent improvement inquality adjusted life years. In ourexperience, MIS- vs. open- multilevelhemilaminectomy is a cost equivalenttechnology for patients with lumbarstenosis associated radicular pain.




251Minimally Invasive Lateral Access Surgeryfor Symptomatic Thoracic Disc Herniation:Initial Clinical Experience with Clinicaland Radiographic OutcomesGlen Pollock, Elias Dakwar, Mark Greenberg, Fernando L. Vale,William D. Smith, Juan S. Uribe Introduction: Symptomatic herniatedthoracic discs remain a surgical challengeand historically have been associatedwith high levels of complications. Whilethe neurologic outcomes have improvedwith the abandonment of thedecompressive laminectomy; surgicalcomplications, morbidity and the needfor fusion have continued. The purpose ofthis study is to demonstrate the safetyand reproducibility of the minimallyinvasive lateral thoracic approach forsymptomatic thoracic herniatedintervertebral discs with clinical andradiological outcomes.Methods:We retrospectively studied 24patients to assess the clinical andradiographic results using minimallyinvasive surgery for the treatment ofthoracic herniated discs. All patientsunderwent a lateral transthoracicapproach utilizing an expandable tuberetractor. Follow up times were anaverage of 21 months. The patients werefollowed with neurologic examination,visual analog score (VAS) and Oswestrydisability index (ODI). Postoperativecomputed tomography was performed toassess the extent of bony resection.Results:The mean blood loss was 415 ml.The mean visual analog scale scoreimprovement for thoracic pain was 4.1.The Oswestry disability index improvedan average of 36%. All discs weresuccessfully removed except in onepatient. One case was complicated bydurotomy and one case was complicatedby worsened myelopathy Asia D to ASIAC. There was no incidence of wrong-levelsurgery.Conclusion:Our early experiencesuggests that the minimally invasivelateral transthoracic approach is safe,reproducible and effective for achievingadequate decompression in thoracic discherniations in a less invasive mannerthan traditional surgical treatmentoptions. This surgical technique allowsthe surgeon to directly visualize andprotect the dura prior to visualizing thelesion without the need to collapse thelung. As this technique is advanced, theapplicability of minimally invasivesurgery will likely be expanded and willafford the opportunity for reducedcomplications.

252Early Radiographic Outcomes of XLIF inthe Minimally Invasive Treatment of AdultScoliosis: Results from a ProspectiveMulticenter Non-randomized Study of 107PatientsFrank M. Phillips, Safdar Khan, Solas Degenerative Study GroupIntroduction: Surgical intervention inadult scoliosis patients has traditionallybeen performed using large openanterior and/or posterior procedures.This report summarizes the earlyradiographic outcomes of a minimally-invasive approach (XLIF) for thetreatment of adult scoliosis, as part of anongoing prospective, multicenter study.Methods: 107 patients were treated foradult scoliosis with XLIF at 14 US centers.Radiographs were collectedpreoperatively and postoperatively at 2weeks, 3, 6, 12, and 24 months.Radiographic analysis included measuresof lumbar lordosis (L1 to S1), coronalCobb angle, device subsidence, anddevice migration.Results: Radiographic follow-up wasavailable for 103 patients who weretreated at 310 levels between T11 and L5.Procedures included 1-6 levels. 73.8% ofpatients were female, average patient agewas 67.8 years, BMI was 28.4 kg/m2, and10.7% were smokers. Supplementalfixation included bilateral pedicle screws(49%), unilateral pedicle screws (26%),and anterolateral plating (7%); theremaining 18% were standalone. At 3months incidence of migration was 0%and subsidence was 26.2%, nonerequiring revision. On average, patientshad normal lordosis preoperatively, with33 patients having abnormal lordosis (>-40°) measuring an average of -28.5°.Lordosis was significantly corrected inhypolordotic patients from preoperativeto 2 weeks (p<0.001) which wasmaintained at 3 months (average 3month lordosis = -35.4°). Significantcorrections in average coronal Cobbangle were observed from preoperative to2 weeks (p<0.001) and maintained at 3months. Coronal correction wassignificantly affected by supplementalfixation (p=0.027) with the greatestcorrections in patients with bilateralposterior pedicle fixation and the least inpatients with no supplemental fixation(average 12.6° vs. 2.6°).Conclusion: Significant reduction indeformity was observed with respect tocoronal Cobb angle and lordosis, and wasmaintained through the three monthevaluation, providing evidence that the

XLIF technique can effectively correctdeformity in the adult scoliosispopulation.

253Economic Impact of Minimally InvasiveSpine Surgery Open vs. MIS SpinalFusion Costs in the Perioperative Period(First 45 Days)Jody A. Rodgers, W.B. Rodgers, John Lucio,Brent Vanconia, Kevin J. DeLuzio Introduction: Improved clinical andradiographic outcomes have beenreported of minimally invasive spinalsurgery techniques in comparison totraditional open approaches. We seek todetermine if fewer complications,reoperations, additional therapies anddiagnostics yields a lower overall costamong minimally invasive patients.Methods:Hospital costs wereretrospectively obtained for all ourcenter’s two level spinal fusions from2005-2008. 101 patients had a traditionalopen procedure, and 109 underwent aminimally invasive fusion. Patients werenot randomized; procedure methodswere employed sequentially. After ourtransition to minimally invasivetechniques in late 2006, no further openprocedures were performed. Costsobtained include surgical procedure andhospitalization, in addition to ensuinghospital costs occurring in the first 45days postop.Results: Average cost of the originalprocedure and hospitalization was 6%less expensive in the MIS group overall,despite higher implant costs in the MISgroup. When combined with allperioperative costs within the first 45days after surgery, the average procedurecost reduction was 10.4%, a savings of$2,825.37 per procedure.Conclusion: Results indicate an overallreduction of costs of MIS two levelprocedures compared to traditional openapproaches. Costs of the surgicalprocedure and hospitalization are lowerin the MIS group. Early numbers indicatethat cost savings increase as length oftime postop increases. The open group,although with longer follow-up, hasdemonstrated a significantly higherincidence of reoperation than the MISgroup comparatively. Thus, ourcontinued cost evaluation into theintermediate and long-term follow-upperiod may demonstrate an ever-increasing improvement in overall costs.




254Perioperative Outcomes andComplications Following XLIF for theTreatment of Adult Scoliosis: Results of aProspective, Non-randomized, MulticenterEvaluationRobert E. Isaacs, Jonathan Hyde, J. AllanGoodrich, W.B. Rodgers, Frank M. Phillips,Solas Degenerative Study GroupIntroduction: Combinedanterior/posterior instrumented fusion isoften performed for the surgicaltreatment of adult scoliosis. Suchprocedures have been associated with ahigh risk of complication, particularly inthe elderly patient population. Lessinvasive surgical approaches to neuraldecompression and fusion have recentlybeen applied in the treatment ofdegenerative scoliosis. This reportsummarizes the perioperativecomplications following lateral fusion forthe correction of degenerative scoliosis.Methods: In a prospective multicenterobservational study of patients whounderwent the XLIF procedure for thetreatment of degenerative scoliosis,perioperative measures were compiled toidentify the short-term outcomes of theprocedure. Intraoperative data collectionincluded surgical details, operative time,estimated blood loss, and complications.Postoperative complications, length ofhospital stay, and neurological statuswere recorded.Results: 107 patients (mean age 68 years;range 45-87) were treated with XLIF. 28%had at least one comorbidity. A mean of4.4 levels/patient (range 1-9) weretreated. Supplemental pedicle screwfixation was used in 75.7% of patients,5.6% had lateral fixation and 18.7% hadstandalone XLIF. Mean operative timeand blood loss were 178min and 50-100cc. Mean hospital stay was 2.9 days(unstaged), 8.1 days (staged; 16.5%), 3.8days overall. 5 patients (4.7%) received atransfusion, 3 (2.8%) required ICUadmission, 1 (0.9%) requiredrehabilitation services. Majorcomplications occurred in 13 patients(12.1%): 2 (1.9%) medical, 12 (11.2%)surgical. Of procedures that involved onlyless invasive techniques (XLIF standaloneor with percutaneous instrumentation),9.0% had one or more majorcomplications. In those withsupplemental open posteriorinstrumentation, 20.7% had one or moremajor complication. Early reoperations(3, for deep wound infections) wereassociated with open posteriorinstrumentation.

Conclusion: The morbidity in adultscoliosis surgery is minimized with lessinvasive techniques. The rate of majorcomplications in this study (12.1%)compares favorably to reports from otherstudies of surgery for degenerativedeformity.

255Correlation of Preoperative Depressionand Somatic Perception Scales withPostoperative Disability and Quality ofLife After Lumbar DiscectomyScott Parker, Kaisorn L. Chaichana,Owoicho Adogwa, Joseph S. Cheng,Matthew J. McGirt Introduction: Lumbar discectomy is acommon surgical procedure performedin the U.S. for patients experiencing backand leg pain. However, patients withcertain psychological predispositionsmay be especially vulnerable to poorclinical outcomes. The goal of thisprospective longitudinal study was todetermine the role that preoperativedepression and somatic anxiety have onlong-term back and leg pain, disability,quality of life for patients undergoingsingle-level lumbar discectomy.Methods: 67 adults undergoingdiscectomy for single-level herniatedlumbar disc underwent prospectivequantitative measurement of leg andback pain (visual analogue scale; VAS),quality of life (Medical Outcomes ShortForm-36; SF-36), and disease-specificdisability (Oswestry Disability Index;ODI) preoperatively, at 6 weeks, 3, 6, and12 months after surgery. Degree ofpreoperative depression andsomatization were assessed using ZungSelf-Rating Depression Scale andmodified somatic perceptionquestionnaire (MSPQ). Multivariateregression analyses were performed toassess associations between Zung andMSPQ scores with achievement of aminimum clinical important difference(MCID) in each outcome measure by 12months postoperatively.Results: Overall, a significantimprovement in VAS-leg, VAS-back, ODI,and SF-36 PCS was observed by 6 weeksafter surgery and maintained throughout12-months follow-up. Increasingpreoperative depression (Zung score) wasassociated with a decreased likelihood ofachieving MCID in disability (p=0.006)and quality of life (p=0.04) but was notassociated with leg (p=0.96) or back pain(p=0.85) by 12 months, Fig1&Table 1.Increasing preoperative somatic anxiety(MSPQ score) was associated withdecreased likelihood of achieving MCID

in disability (p=0.002) and quality of life(p=0.03) but was not associated with leg(p=0.64) or back pain (p=0.77) by 12months, Fig1&Table 1.Conclusion: Zung and MSPQ are valuabletools at preoperatively risk stratifyingpatients who may not experienceclinically relevant improvement indisability and quality of life afterdiscectomy. Efforts to address theseconfounding and underlyingcontributors of depression andheightened somatic anxiety may improveoverall outcomes after lumbardiscectomy.

256Microdiscectomy Improves Pain-associated Depression, Somatic Anxiety,and Mental Well-being in Patients withHerniated Lumbar DiscScott Parker, Richard L. Lebow, Owoicho Adogwa, Adam S. Reig, Joseph S. Cheng, Matthew J. McGirt Introduction: In a multicenter,prospective, longitudinal outcome study,we assessed the prevalence ofpreoperative depression, somatization,and mental well-being in patients withherniated lumbar discs and the effect thatmicrodiskectomy had on thesepsychological disturbances.Methods: Patients undergoing surgicaldiscectomy at five medical institutions fora single-level, herniated lumbar disc wereprospectively assessed preoperatively, at6 weeks, 3, 6, and 12 months after surgeryfor visual analog scale for low back pain(BP-VAS) and leg pain (LP-VAS),depression via Zung Self-RatingDepression Scale, heightened anxietysomatic perception via the ModifiedSomatic Perception Questionnaire(MSPQ), and mental well-being via theSF-36 mental component summary(MCS).Results: 100 patients were available for 1-year follow-up. Mean BP-VAS and LP-VAS was significantly improved at 6 weeksand remained improved at 3, 6, 9, and 12months postoperatively,Figure 1. Asignificant improvement in SF-36 MCSwas also observed by 6 weeks aftersurgery (42±14 vs. 48.2±12, p<0.01), and itcontinued to improve over 12-months,Figure2. A significant improvement inMSPQ score was not observed until 3months after surgery (9±7 vs. 6.6±6.9,p<0.05). A significant improvement inZUNG depression score was not observeduntil 12 months after surgery (19±11 vs.14.4±10.9, p<0.05). 67% of somatasizedpatients (MSPQ>12) became non-somatsized one year post-surgery. 70% of




clinically depressed patients (ZUNG>33)became non-depressed one year post-surgery. Improvement in SF-36 MCS,ZUNG, and MSPQ each significantlycorrelated (p<0.001) with improvement inBP-VAS and LP-VAS.Conclusion:The majority of patientsdefined as somatized and depressedpreoperatively returned to good mentalwell-being following surgery.Improvement in pain and overall mentalwell-being were seen acutely aftermicrodiskectomy, while improvement insomatic anxiety and depression occurredmonths later. Microdiskectomysignificantly improves pain-associateddepression, somatic anxiety, and mentalwell-being in patients with a herniatedlumbar disc. In addition, futurecomparative effectiveness research onsurgical vs. nonoperative treatment ofdisc herniation should include mentalwell being as an outcome measure.

257Management of Degenerative LumbarStenosis Related to Meyerding Grade ISpondylolisthesis: The Reappraisal ofUnilateral LaminotomyMario Ganau, Enrico De Micheli, Massimo GerosaIntroduction:The management ofdegenerative lumbar stenosis related toMeyerding Grade I sponsylolisthesis isstill a matter of debate: both laminectomyand laminotomy have been advocated,but sometimes fusion may represent anovertreatment. A prospective trial wasconducted in 38 patients to evaluate theimpact of unilateral laminotomy forbilateral decompression of the lumbarcanal in such cases.Methods:On admission, patients (fatioF:M = 27:11; mean age 69y) underwentclinical evaluation using the BeaujonScoring System (BSS) and VAS scale.Segmental instability detected ondynamic x-rays were consideredexclusion criteria. CT and/or MRI studiesof the lumbar spine were performed in allcases preoperatively and 12 monthsfollowing surgery. Outcome wasevaluated in two stages: at dischargeusing the BSS and VAS scales, and at long-term follow-up time (12 monthsminimum) using the MacNabclassification (grade I-excellent, II-good,III fair, IV-poor).Results: At discharge, clinicalimprovement assessed by BSS and VASscales was significant in all patients; butmore interestingly it was sustained evenat long-term follow-up (mean 40months): 81% of the patients were still in

excellent conditions according toMacNab classification. Following surgerythe lumbar spinal canal diameters(anteroposterior, transpedicular,interapophyseal) were significantly largerthan the preoperative measurements,and no cases of vertebral instability werefound.Conclusion:The results of our studyindicate that, whenever evidence ofspinal instability is ruled out, unilaterallaminotomy is a valid surgical option inthe treatment of degenerative lumbarstenosis related to Meyerding Grade Ispondylolisthesis.

258Determination of Minimum ClinicallyImportant Difference (MCID) in Pain,Disability, and Health State Utility AfterTransforaminal Lumbar Interbody Fusion(TLIF) for Degenerative LumbarSpondylolithesisScott Parker, Owoicho Adogwa, Alexandra Paul, Bill Anderson, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirt Introduction: Spinal surgical outcomestudies rely on patient reported outcomes(PRO) to assess treatment effect.Commonly used health-related quality-of-life questionnaires include pain scalesfor back and leg pain (Visual AnalogScale), the Oswestry Disability Index(ODI), and the EuroQol-5D health survey(EQ-5D). A shortcoming of thesequestionnaires is that their numericalscores lack a direct meaning or clinicalsignificance. Hense, the concept ofminimum clinical important difference(MCID) has been put forth as a measurefor the critical threshold needed toachieve treatment effectiveness. By thismeasure, treatment effects reaching theMCID threshold value imply clinicalsignificance and justification forimplementation into clinical practice.Methods: In 45 patients undergoingtrans-foraminal lumbar interbody fusion(TLIF) for low-grade degenerative lumbarspondylolithesis associated back and legpain, PRO measures of BP-VAS, LP-VAS,ODI, and EQ-5D were administeredpreoperatively and 2-yearspostoperatively and 2-year change scorescalculated. Four established anchor-based MCID calculation methods wereutilized to calculate MCID (1. averagechange, 2. minimum detectable change(MDC), 3. change difference, 4. receiveroperating characteristic curve analysis)for two separate anchors (healthtransition index (HTI) of the Short Form-36 and satisfaction index).

Results:The mean±SD two-yearimprovement in BP-VAS, LP-VAS, ODI,and EQ-5D were 4.3±2.9, 3.8±3.4,19.5±11.3, and 0.43±0.44,respectively(Figure 1). The four MCIDcalculation methods generated a range ofMCID values for each of the PROs(BP-VAS:2.1-5.3, LP-VAS:2.1-4.7, ODI:11-22.9,EQ-5D:0.15-0.54),Table 1. The mean areaunder the ROC curve (AUC) from the fourPRO-specific calculations was greater forthe HTI vs. satisfaction anchor (HTI AUC:0.73 vs. satisfaction AUC: 0.69),suggesting HTI as a more accurateanchor.Conclusion:TLIF specific MCID is highlyvariable based on calculation technique.The MDC approach with SF-36 HTIanchor appears to be most appropriatefor calculating MCID because it provideda threshold above of the 95% confidenceinterval of the un-improved cohort(greater than the measurement error),was closest to the mean change scorereported by improved and satisfiedpatients, and was least affected by thechoice of anchor. Based on MCD methodwith HTI anchor, MCID following TLIFare 2.4 points for BP-VAS, 2.5 points forLP-VAS, 15.6 points for ODI, and 0.40QALYs for EQ-5D.



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300Attenuating Experimental Spinal CordInjury by Hyperbaric Oxygen: StimulatingProduction of Vasculoendothelial and GlialCell Lines Derived Neurotrophic GrowthFactors and Interleukin-10Po-An Tai, Chen-Kuei Chang, Ko-Chi Niu,Mao-Tsun Lin, Chien-Min Lin, Wen-Ta ChiuIntroduction:The present study was tofurther examine the mechanismsunderlying the beneficial effects ofhyperbaric oxygen (HBO2) onexperimental spinal cord injury (SCI).Methods: Rats were divided into threemajor groups: (1) sham operation(laminectomy only); (2) laminectomy +SCI+ normobaric air (NBA; 21% O2 at 1ATA); and (3) laminectomy + SCI + HBO2(100% O2 at 2.5 ATA for 2 hours). Spinalcord injury was induced by compressingthe spinal cord for 1 minute with ananeurysm clip calibrated to a closingpressure of 55 g. HBO2 therapy wasadopted immediately after SCI.Behavioral tests of hind limb motorfunction measured by Basso, Beattie,Bresnahan locomotor scale wasconducted at day 1 to 7 after SCI. Thetriphenyltetrazolium chloride stainingand terminal deoxynucleotidyltransferase-mediated deoxyuridinetriphosphate biotin nick end labelingassay were also conducted after SCI toevaluate spinal cord infarction andapoptosis respectively. Both glial cell linesderived neurotrophic nerve growth factor(GDNF) and vascular endothelial growthfactor (VEGF) positive cells and cytokinesin the injured spinal cord were assayed byimmunofluorescence and commercialkits, respectively.Results: It was found that HBO2 therapysignificantly attenuated the SCI-inducedhind limb dysfunction, spinal cordinfarction and apoptosis, andoverproduction of spinal cordinterleukin-1ß and tumor necrosis factor-a. In contrast, the numbers of bothGDNF-positive and VEGF-positive cellsand production of spinal cordinterleukin-10 during SCI were all

significantly increased by HBO2.Conclusion:These data suggested thatHBO2 may attenuate experimental SCI bystimulating production of GDNF, VEGFand interleukin-10.

301FDA IDE Clinical Outcomes for 110Symptomatic Lumbar Stenosis PatientsTreated with ACADIA™ at 16 CentersW.B. Rodgers, Darryl J. Dirisio, John J. Regan, Charles A. Hartjen, Kenneth Pettine, Jim A. Youssef, Leo R. Spector, Joseph J. Marzluff, Jason M. Highsmith, Neel Anand, Kevin A. Rahn, Robert Shugart, Craig S. Humphreys, Thomas B. Briggs,Chad J. Morgan, John F. Ferguson, Wade Ceola, Randall DryerIntroduction:Decompression with fusionis often indicated for patients withlumbar radiculopathy and/or neurogenicclaudication especially in cases of pre-existing or iatrogenic instability.Alterations in lumbar biomechanics dueto arthrodesis have the potential toaccelerate degenerative changes atneighboring levels. Placing ACADIA™ asan alternative to fusion may provide therequired stability while preservingadjacent level biomechanics, potentiallyreducing the risk of accelerateddegenerative changes. An FDA IDEclinical study has been undertaken todetermine the safety and efficacy of thisnew treatment option.Methods: Perioperative data, OswestryDisability Index (ODI) scores, ZurichClaudication Questionnaire (ZCQ) scores,and Visual Analog Scale (VAS) pain scoreswere recorded. Patient evaluations wereconducted at baseline, 6 weeks, 3, 6, 12and 24 months.Results: Enrollment has reached 110patients with 99, 60 and 20 out to 6, 12and 24 months, respectively. The meanage, BMI, operative time, blood loss andhospital stay were 61, 30kg/m2, 186minutes, 407mL, and 3.0 days,respectively. The L3/4, L4/5 and L5/S1levels accounted for 7.3%, 87.3% and5.5% of the cases, respectively. Thepercent improvement in mean ODI scoreat 24 months was 75%. The percentimprovements in mean VAS back and legpain at 24 months were 82% and 83%,respectively. The mean ZCQ SymptomSeverity and Physical Function pointsimproved at 12 months were 1.82 and1.24, respectively. The mean ZCQ patientsatisfaction score was 1.37 at 12 months.Conclusion:This new treatment mayrepresent a clinically viable alternative tofusion. Improvements in functional and

pain outcome measures were seen at allpostoperative time points and a high level of patient satisfaction has beendocumented. The clinical safety andefficacy of this procedure will be deminedat the conclusion of the ongoingprospective randomized FDA IDE pivotal trial.

302Direct Vertebral Body Derotation: HowMuch Correction of the Rib Deformity CanBe Expected?Amer F. Samdani, Steven Wei-Hung Hwang,Baron Lonner, Peter Newton, Michelle Marks, Tracey Bastrom, Randal Betz, Patrick CahillIntroduction:Direct vertebral bodyderotation (DVBD) is a powerful tool inthe surgical correction of rotational spinedeformity and has decreased the use ofthoracoplasty for rib deformitycorrection. In this study, we sought todetermine the extent of rib deformitycorrection which can be expected withDVBD and factors which may correlatewith improved correction.Methods: A prospective, longitudinaldatabase was queried to identify AISpatients who underwent a posteriorspinal fusion with 2-year follow-up andLenke 1-3 curves. All patients hadundergone DVBD maneuvers (en-bloc,segmental or both) during their surgery.Patients having undergone concurrentthoracoplasty were excluded from thestudy. The absolute change and percentchange from preoperative inclinometerreadings were correlated withpreoperative clinical and radiographicdata using a Pearson correlation.Results: 148 patients were identified whofulfilled the inclusion criteria. The meanage was 14.8 ± 2.0 years with a meanprimary thoracic curve of 55.3 ± 9.3º. Theprimary thoracic curve reduced to 28.1 ±12.0º on bending radiographs translatingto a flexibility of 49%. The meanpreoperative inclinometer reading was14.9 ± 4.5° which reduced to 7.5 ± 4.0°post-op for a 50% improvement. Weattempted to correlate 23 of the mostcommonly used pre-op radiographicmeasures. Interestingly, none correlatedwith rib deformity correction including:preoperative rib deformity (p=0.16),thoracic curve flexibility (p=0.71), andthoracic curve magnitude (p=0.78). Anadditional 80 patients had apical vertebralrotation measured using the apicalvertebral body-rib ratio. Neither the initialratio (p=0.52), nor the change in ratioduring bending radiographs (p=0.45)correlated with inclinometer results.

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Conclusion:Utilizing DVBD, the surgeoncan expect a 50% reduction in the ribdeformity as assessed by inclinometer.This is irrespective of the pre-opinclinometer reading, thoracic curveflexibility, and degree of apical rotationon standing and bending x-rays.

303Age Increases the Risk of PostoperativeDysphagia and Aspiration After AnteriorOdontoid Screw FixationJonathan A. Grossberg, Heather Spader,Adetokunbo A. OyeleseIntroduction:Type II odontoid fracturesare the most common spinal fracture inthe elderly population and may bemanaged with halo immobilization,posterior fusion, and anterior odontoidscrew fixation. Anterior odontoid screwfixation has several advantages overposterior fusion, including: reducedsurgical time, decreased postoperativepain, preserved range of motion, earliermobilization, and decreasedpostoperative narcotic requirement. Wereview our experience using anteriorodontoid screw fixation in Type IIodontoid fractures in the elderly andnon-elderly populations.Methods:Demographic and outcomedata were retrospectively collected in 30consecutive patients with type IIodontoid fractures treated with anteriorodontoid screw fixation.Results:Mean patient age was 70.7(Range: 20-92); eighteen of the patientswere male and twelve were female. Allpatients had successful placement of asingle anterior odontoid screw withoutintraoperative complication.Complications included pneumonia innine patients (30%), gastrostomy tubeplacement due to patient failing swallowevaluation in thirteen patients (43%), andvocal cord paralysis in one patient (3.3%).Patients over the age of seventy-fiveaccounted for twelve of the thirteen (92%)gastrostomy tube placements and eightof the nine (88.9%) pneumoniasrespectively. The difference in rates ofgastrostomy tube placement andpneumonia for the older patients wereboth found to be statistically significantwith a P of <.0001 for gastrostomy tubesand a P<.0.02 for pneumonias.Conclusion: Anterior odontoid screwfixation is an effective treatment optionfor patients with Type II odontoidfractures. In the elderly population,however, the benefits of the proceduremust be weighed against the risks ofpostoperative dysphagia requiringgastrostomy and pneumonia.

304Disc Herniation Induces 55% Increase inMultifidus Load in Axial RotationBruce Robie, Sebastian Dendorfer, Soren Torholm, John RasmussenIntroduction:The multifidus is a keystabilizer of the spine[1], especially inaxial rotation[2]. Its loss of size has beenshown in patients with symptomaticherniations[3]. Cadaver testing hasshown that herniations significantlydecrease the segment stiffness in axialrotation[4]. We hypothesize that this lossof segment stiffness results in an overloadof the multifidus, leading to muscleatrophy. The purpose of this study is toexamine the mechanical effect of alumbar disc herniation, via the loss ofsegmental stiffness in axial rotation, onthe force required by the differentbranches of the multifidus.Methods:We used the AnyBody ModelingSystem™, a validated model[5,6]consisting of more than 1000 individualmuscle branches to analyze flexion-extension, lateral bending and axialrotation motion of a standing adult underthe influence of gravity (Fig. 1).Simulations were run using segmentstiffness at L5-S1 from cadaver test datafor normals and for herniatedsegments[4]. The analyzed parameterswere the forces in all branches of themultifidus muscles of the model on theright side of the spine.Results:The herniation did result insignificant increases in the force in themultifidus. The greatest impact was inaxial rotation, where there was a 55%increase in force in a multifidus branchcrossing the effected segment (Fig. 2).Lesser impact was seen in flexion-extension (maximum 33% increase), anda small decrease was seen in lateralbending.Conclusion:The mechanical effect of theherniation on the multifidus was greatestin axial rotation, significantly increasingthe peak load required by branches of themultifidus crossing the herniated level.This overload may be a cause of muscleatrophy in patients with herniations.Limiting motion in axial rotation may berequired to protect the multifidus fromatrophy in patients with herniations.

305Neurovascular Complications of CervicalPedicle Screw Fixation in the CervicalPathologiesKadir KotilIntroduction: Retrospective study of aprospectively followed cohort. Using tocervical transpedicular fixation (CPF)

technique is very low in the routinepractice, as the pedicle is thin and risk ofneurovascular damage is high. In thisstudy, we emphasized the neurovascularcomplications of cervical transpedicularfixation in the different cervicalpathologies.Methods: Postoperative neurovascularinjury of the transpedicular screws of the210 pedicles of the 45 patients weoperated due to traumatic andnontraumatic cases in the cervical region,were investigated. Fixation wasperformed between C3 and C7, and iliacwing and lamina were used as autograftsfor fusion.Results: In postoperative computedtomography (CT) scan, the applied screwwas observed to have directly penetratedinto the vertebral foramen in only two(0.9 %) pedicle during the fixationprocess; however, the blood circulationappeared normal in angiography. Interms of screw-pedicle relations, thescrews were at their correct places in 174pedicles (82.8%), while non-critical lateralorientation was detected in 14 (6.6%),and medial orientation in another 16pedicles (7.3%). Fusion ratio was 100%.There was no morbidity or mortality. Theaverage length of the screws used 32 mmfor C3-7. A total of 204 (92.3%) pedicles ofthis series had an intrapedicular width of3.2 mm or less. The cases were followedup for a total of 17 to 34 months (25.7).Conclusion:Use of the CPF provides avery strong three column stabilizationbut also carries a high risk of pedicleperforation without neurovascular injury.No mortality or morbidity. Free handtechnique with experienced surgeon isacceptable for CPF in the differentcervical pathologies.

306Posterior Approach for ThoracolumbarCorpectomies with Expandable CagePlacement and CircumferentialArthrodesis: A Multicenter Case Series of67 PatientsChristoph Hofstetter, Dean Chou,Benjamin Newman, Henry E. Aryan,Federico Girardi, Roger HartlIntroduction:Multicenter trialinvestigating outcome and durability ofsingle-stage thoracolumbar corpectomyusing expandable cages via a posteriorapproach.Methods: Retrospective chart review of 67consecutive patients following single-stage thoracolumbar corpectomies withcircumferential reconstruction foroncologic, traumatic and osteomyeliticpathologies. Circumferential




reconstruction was accomplished byusing expandable cages with posteriorinstrumentation and fusion. Correctionof sagittal deformity, ASIA score andcomplications were recorded.Results: Single-stage thoracolumbarcorpectomies resulted in an averagecorrection of sagittal deformity by 6.2degrees at a mean follow-period of 20.5months. At last follow-up, we observed afusion rate of 68% for traumatic andosteomyelitic fractures. Approximatelyhalf of the patients remainedneurologically stable. Improvement ofneurological function was seen in 23patients (38%) while 7 patients (11%)suffered from a decrease of lowerextremity motor function. Deteriorationof neurological function was due toprogression of metastatic disease in 5patients. A total of 5 constructs (7%)failed. Three of these constructs wereplaced for traumatic fractures, one for apathologic and one for an osteomyeliticfracture. Other complications includedepidural hematomas in 3 patients andpleural effusions in 2 patients.Conclusion: Single-stage posteriorcorpectomy and circumferentialreconstruction was performed inmultiple centers with consistent outcomeover a wide range of pathologies.Correction of sagittal deformity wassustained and the neurological outcomewas good in the majority of patients. 18%of acute traumatic fractures, however,required revision of the construct.

307Why Lumbar Artificial Disc Replacements(ADR) FailKenneth Pettine, Christian SchlichtIntroduction:To determine why ADR’sfail. Ninety-one patients undergoingADR. at one IDE site were evaluated forclinical success.Methods: Failure was defined as less than50% improvement in ODI and VAS or anyadditional surgery at index or adjacentspine motion segment. Three ADR’s wereevaluated: Maverick™ (M) 25 patients,Charité™ (C) 31 patients, Kineflex™ (K)35 patients. All procedures were one levelperformed at L4-5 or L5-S1.Demographics and inclusion/exclusioncriteria were similar and will bediscussed. Facet pain was diagnosed byfacet block and significant clinicalimprovement after facet rhizotomy.Results:Overall clinical failure occurredin 26%, (24 of 91 patients) (M) 28%, (7 of25 patients); (C) 39%, (12 of 31 patients);(K) 14%, (5 of 35 patients) at two-yearfollow-up. The type of A.D.R. makes a

difference. Causes of failure included:facet pathology 46% of failure patients,(11 of 24). Implant complicationsoccurred in 6% of the total patients and25% of the failure patients, (6 of 24).Patients with additional orthopedic ormedical pathology or disability/narcoticissues occurred in 29% (7 of 24), of thefailure group. Despite the fact thesepatients were considered failures basedon ODI and VAS, they reported a 92%satisfaction with the ADR and wouldrepeat the surgery for the same result.Interestingly, ADR patients are ofteneither a clinical success at three-monthfollow-up or a possible failure. Only fivepatients went from a success to failureafter three months. One was an infectionone year after ADR and four patientsdeveloped additional pathologyunrelated to their ADR. Only one patientwent from a failure to success after a facetrhizotomy one year after ADR.Conclusion:These results indicate overallclinical success can be improved most bypatient selection and implant type.

308Association of Surgical Resection andSurvival in Patients with MalignantPrimary Osseous Spinal Neoplasms fromthe Surveillance, Epidemiology, and EndResults (SEER) DatabaseMatthew J. McGirt, Kaisorn L. Chaichana,Debraj Mukherjee, Scott Parker, Owoicho Adogwa, Joseph S. Cheng, Oran Aaronson, Ziya L. GokaslanIntroduction:While surgical resectionhas been shown to improve short-termlocal disease control, it remains debatedwhether surgical resection is associatedwith improved overall survival in patientswith malignant primary osseous spinalneoplasms. We reviewed survival datafrom a U.S. cancer registry spanning 30years to determine if surgical resectionwas independently associated withoverall survival.Methods:The SEER registry (1973-2003)was queried to identify cases ofhistologically confirmed primary spinalchordoma, chondrosarcoma,osteosarcoma, or Ewing’s sarcoma of themobile spine and pelvis via ICD-O-2coding. Patients with systemic metastasiswere excluded. Age, gender, race, tumorlocation, and primary treatments wereidentified. Extent of local tumor invasionwas classified as confined withinperiosteum vs. extension beyondperiosteum to surrounding tissues. Theassociation of surgical resection withoverall survival was assessed via Coxproportional-hazards regression analysis

adjusting for age, radiotherapy, andtumor invasiveness.Results: 827 patients were identified withnon-metastatic primary osseous spinalneoplasms (215 chordoma, 282chondrosarcoma, 158 osteosarcoma, 172Ewing’s sarcoma), Table 1. Overallmedian survival was histology specific(chordoma: 96 months, Ewing’s sarcoma:90 months, chondrosarcoma 88 months,osteosarcoma 18 months). Adjusting forage, radiation therapy, and extent of localtumor invasion in patients with isolated(non-metastatic) spine tumors, surgicalresection was independently associatedwith significantly improved survival forchordoma [Hazard Ratio (95%Confidence Interval; 0.617 (0.25-0.98)],chondrosarcoma [HR (95%CI); 0.153(0.07-0.36)], osteosarcoma [HR (95%CI);0.382 (0.21-0.69)], and Ewing’s sarcoma[HR (95%CI); 0.494 (0.26-0.96)]. Figures 1-3.Conclusion: In our analysis of a 30-yearU.S. population based cancer registry(SEER), patients undergoing surgicalresection of primary spinal chordoma,chondrosarcoma, Ewing’s sarcoma, orosteosarcoma demonstrated prolongedoverall survival independent of patientage, extent of local invasion, or location.Surgical resection may play a role inprolonging survival in the multi-modalitytreatment of patients with thesemalignant primary osseous spinalneoplasms.

309Development of a Novel IntravertebralHuman Prostate Adenocarcinoma RatModel for the Study of IntravertebralMetastatic Spine DiseaseRachel Sarabia-Estrada, Camilo A. Molina, Guergana Panayotova,Clinton Jung, Ziya L. Gokaslan, Timothy F. Witham, Jean-Paul Wolinsky,Ali Bydon, Daniel M. SciubbaIntroduction: Prostate carcinoma is themost commonly diagnosed malignancyand second most common cause ofcancer-related death in US men. Themajority of these patients suffer frombone metastases, with the spine as themost common osseous site. Nevertheless,a practical and reproducible model ofspinal metastatic disease using humanprostate cancer tissue has not beenreported. We report the first animalmodel of metastatic epidural spinal cordcompression using human prostatecancer.Methods:Human prostate cancer cellline (PC-3) was injected subcutaneouslyinto the flank of athymic male rats.




Following in situ growth, tumor wasremoved for spine transplant. Group 1(n=6) rats underwent a transperitonealapproach followed by implantation oftumor tissue into the L6 vertebra. Group 2(n=6) rats were subjected to the sameprocedures but no tumor was implanted.Animals were functionally assessed dailyvia a kinematic analysis of locomotion.Pathological growth of tumor wasassessed grossly, histologically, and viacomputed-tomography (CT) imaging 23days after tumor implantation.Results:Microscopic morphology of PC3tumor was confirmed by histologicalanalysis with H&E. In Group 1, the PC3tumor was successfully established in theL6 vertebrae body, as confirmedhistologically and via CT imaging.Kinematic analysis of locomotion inGroup 1 showed decline in coordination,balance, and leg swing at 15 days,consistent with epidural compression,while locomotion was unchanged inGroup 2.Conclusion:This study demonstrates anovel model of metastatic spine diseaseusing a human prostate cancer cell line.Functional, radiographic, andhistopathologic data provide evidence ofthe practicality and reliability of themodel as the basis for future experimentson human prostate spine tumors.

310Postoperative Infection After MinimallyInvasive vs. Open Transforaminal LumbarInterbody Fusion (TLIF): Literature Reviewand Cost AnalysisScott Parker, Owoicho Adogwa, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirtIntroduction: Surgical site infection (SSI)in the setting of lumbar fusion isassociated with significant morbidity andmedical resource utilization. To date,there have been no studies conductedwith sufficient power to directly comparethe incidence of SSI following minimallyinvasive (MIS) vs. open TLIF procedures.Furthermore, studies are lacking thatquantify the direct medical cost of SSIfollowing fusion procedures. We set out todetermine the incidence of SSI in patientsundergoing MIS vs. open TLIF reported inthe literature and to determine the directhospital cost associated with thetreatment of SSI following TLIF at ourinstitution.Methods: A systematic Medline searchwas performed to identify all publishedstudies assessing SSI after MIS or openTLIF. The cumulative incidence of SSI wascalculated from all reported cohorts andcompared between MIS vs. open TLIF. Inorder to determine the direct hospitalcosts associated with the treatment of SSI

following TLIF, we retrospectivelyreviewed 120 consecutive TLIFsperformed at our institution, assessed theincidence of SSI, and calculated the SSI-related hospital costs from accountingand billing records.Results:To date, there have been 10 MIS-TLIF cohorts (362 patients) and 20open-TLIF cohorts (1133 patients)reporting incidence of SSI. Thecumulative incidence of reported SSI wassignificantly lower for MIS vs. open-TLIF(0.6% vs. 4.0%, p=0.0005). In ourexperience with 120 open TLIFprocedures, SSI occurred in 6 (5.0%)patients. The mean hospital costassociated with the treatment of SSIfollowing TLIF was $29,110 in these sixcases. The 3.4% decrease in reportedincidence of SSI for MIS vs. open-TLIFcorresponds to a direct cost-savings of$98,974 per 100 MIS-TLIF proceduresperformed.Conclusion: Postoperative woundinfections following TLIF are costlycomplications. MIS vs. open TLIF isassociated with a decreased reportedincidence of SSI in the literature and maybe a valuable tool in reducing hospitalcosts associated with spine care.



NEUROSURGICAL LEADERSHIP AMBASSADOR




311Utilization of Spinal Fusion for IsolatedLumbar Degenerative Disc Disease andLong-term Development of AssociatedSpinal Pathologies: A Population-basedStudyMatthew J. McGirt, Owoicho Adogwa, Jim Lesko, Terra Slaton, Jason Lerner,Luella Engelhart, Michael Y. WangIntroduction:The optimal managementof lumbar degenerative disc disease(DDD) in the setting of isolatedmechanical back pain remains debated.To date, no nationally representativepopulation-based studies have exploredthe relative prevalence of fusionprocedures for lumbar DDD.Furthermore, limited information isavailable on the long-term progression ofsegmental spinal degeneration inpatients with medically managed isolatedlumbar DDD. We assess the prevalence offusion procedures and the long-termdevelopment of associated degenerativespine diagnoses in patients with isolatedlumbar DDD from a national claimsdatabase representing more than 25million patients per year.Methods:The MarketScan® CommercialClaims and Encounters and TheMedicare Supplemental andCoordination of Benefits databases (2003-2008) were queried to identify all patientswith a new diagnosis of isolated lumbarDDD utilizing ICD-9-CM codes. Kaplan-Meier survivorship analysis was used toassess the five-year cumulative incidenceof surgical intervention and newdiagnoses of associated spinalpathologies.Results: 3,066 patients were identifiedwith a new diagnosis of isolated lumbarDDD (mean age: 59±13 years,female:1,832 (60%)). Over a five-yearfollow-up period, the cumulativeincidence of lumbar fusion was 2.19%(95%CI: 1.72-2.77%), Figure 1. Forpatients with medically managed DDD,21.58% developed a later diagnosis ofradiculopathy or stenosis, Figure 2.Surgical decompression(laminectomy/discectomy) for ensuingradiculopathy/stenosis was performed inonly 2.94% of patients, Figure 3. By fiveyears, only 1.44% of patients had receiveda new diagnosis of spondylolithesis,Figure 4.Conclusion:This population-based studyof a national claims database suggeststhat the vast majority of patients withisolated lumbar DDD in the United Statesare non-surgically managed. By five yearsafter diagnosis, one-fifth of patients with

conservatively managed lumbar DDDwere subsequently diagnosed withsymptomatic nerve root compression.Subsequent nerve root compression wasmedically managed in the majority ofcases. This study suggests that in theUnited States fusion procedures forlumbar DDD are performed in a smallminority of patients and that medicallymanaged patients should be monitoredfor progressive lumbar degeneration.

312Cost Effectiveness of Minimally Invasivevs. Open Transforaminal Lumbar InterbodyFusion (TLIF) for DegenerativeSpondylolithesis Associated Low-backand Leg Pain Over Two-yearsScott Parker, Owoicho Adogwa, Brandon J. Davis, Joseph S. Cheng, Oran Aaronson, Matthew J. McGirtIntroduction:Minimally invasivetransforaminal lumbar inter-body fusion(MIS-TLIF) for lumbar spondylolithesisallows for surgical treatment of back andleg pain while theoretically minimizingtissue injury and accelerating overallrecovery. While prior studies havedemonstrated shorter length of hospitalstay and reduced blood loss with MIS- vs.open-TLIF, short- and long-termoutcomes have been equivocal. Nostudies to date have evaluated thecomprehensive healthcare costsassociated with TLIF procedures norassessed the cost-utility of MIS vs. open-TLIF.Methods: Forty patients undergoing MIS-TLIF (n=20) or open-TLIF (n=20) forgrade I degenerative spondylolithesisassociated back and leg pain wereprospectively studied. Total back-relatedmedical resource utilization, missedwork, and health-state values (qualityadjusted life years (QALYs), calculatedfrom EQ-5D with U.S. valuation) wereassessed after two year follow-up. Two-year resource use was multiplied by unitcosts based on Medicare nationalallowable payment amounts (direct cost)and work-day losses were multiplied bythe self-reported gross-of-tax wage rate(indirect cost). Difference in mean totalcost per QALY gained for MIS- vs. open-TLIF was assessed as incrementalcost-effectiveness ratio (ICER: COSTmisCOSTopen/QALYmis - QALYopen).Results:MIS vs. open-TLIF cohorts weresimilar at baseline(Table1). By two-yearspostoperatively, patients undergoingMIS-TLIF reported a mean QALYs gainedof 0.50, and open-TLIF patients reported0.41 QALYs gained (0.50 vs. 0.41, p=0.23),Figure 1. Mean total two-year cost of MIS-

and open-TLIF was $35,996 and $44,727,respectively(Table 2). MIS- vs. open-TLIFwas associated with a mean two-year costsavings of $8,731 per patient whileproviding equivalent QALYs gained(ICER).Conclusion: Both MIS- and open-TLIFsignificantly improved quality of life,however, the MIS approach wasassociated with decreased total costs,making it a cost effective advancement inthe surgical technique of TLIF forspondylolithesis-associated back and legpain.

313Endonasal vs. Transoral OdontoidResection: A Systematic Meta-Analysis ofOutcomesDaniel M. S. Raper, Ricardo Jorge Komotar,Robert M. Starke, Vijay K. Anand, Theodore H. SchwartzIntroduction:Odontoid resection may beindicated in ventral cervicomedullarycompression. Surgical approaches havetraditionally utilized a transoraltechnique, which may carry significantmorbidity. Endonasal odontoid resectionrepresents a new technique that providesdirect, minimal access to the odontoidprocess with maximal preservation ofanatomic structures. Limited evidence-based data exists to guide clinicaldecisions.Methods:We performed a MEDLINE(1950-2010) database search to identifyrelevant studies. Comparisons were madebetween endonasal and transoral cohortsfor patient and tumor characteristics andpostoperative complications. Clinicaloutcomes were classified into ‘improved’,‘stable’, or ‘deteriorated’ groups. Statisticalanalyses of categorical variables werecarried out using Mann Whitney U, Chi-square and Fisher’s exact tests.Results: 40 studies, involving 764patients, were included. The endonasalcohort had a significantly lower rate ofsoft palate incision (0.0% vs. 33.6%,p=0.005). There was no difference incomplete odontoid resection betweencohorts. In the endonasal cohort, therewere no cases of postoperative soft palaterepair, atlanto-occipital instability,wound dehiscence, CSF leak ormeningitis. Patients in the endonasalgroup had a shorter time to extubation(p<0.0001) and oral feeding (p=0.0025).There was a significantly higherpercentage of patients with improvedoutcome in the endonasal cohort (100%vs. 73.3%, p=0.009).Conclusion:Our systematic meta-analysis provides evidence-based support




for the endonasal approach as a safe andeffective alternative to traditionaltransoral surgery for odontoid lesions.Indeed, results in appropriately selectedcases appear to be superior for a varietyof outcome measures. Furtherinvestigations comparing cost and lengthof stay are warranted.

314Skin Derived Precursor Cells (SKPs)Promote Return of ElectrophysiologicalFunction in the Rat Tibial Nerve Model ofAdriamycin Induced DemyelinationJoey Kevin Grochmal, Rajiv Midha,Sundeep DhaliwalIntroduction: Skin derived precursor cells(SKPs) can mimic the phenotypicappearance of Schwann cells whenpredifferentiated in vitro (SKP-SCs), andare a reliable autologous source ofSchwann cells that survive inconsiderable numbers when micro-injected into nerve grafts and denervatednerve. Our hypothesis is that SKP-SCs canproduce morphologically andelectrophysiologically functional myelinas they ensheath axons. We are testingthis hypothesis in a model of focaldemyelination of the rat tibial nerve.Methods:We unilaterally injected 500,000GFP-L4 labeled SKP-SCs into the tibialnerves of 10 adult Lewis rats, while asecond group of 10 received 500,000 GFP-L4 labelled Schwann cells in the sameparadigm. A third group (n=10) receivesmedia alone. This was done 9 days after ademyelinating tibial nerve lesion wascreated using a 30ul injection of12.5ug/ml Adriamycin (1). Baselineelectrophysiology was performed on allanimals prior to adriamycin injection,and all animals are being followed withnerve conduction studies and forcompound motor action potentials(CMAPs) every 3 days until 42 days post-initial injection. Animals from each groupare being periodically sacrificed formorphological andimmunohistochemical analysis, usinganti-voltage gated sodium channel, anti-voltage gated potassium channel, as wellas anti-CASPAR antibodies.Results: Preliminary results (n=5/group)indicate that the animals which receivedcell-injection therapy demonstrate asignificant earlier return of CMAPs,suggesting quicker reversal ofdemyelination conduction block than thecontrol media injection group. The SKP-SC group also demonstrates superiorrecovery than the SC group (figure 1).Conclusion:We anticipate the SKP-SCgroup will continue this trend, on par

with or better than the Schwann cellgroup. We also predict that SKP-SCs willparticipate in functional nodes of Ranvierformation, as demonstrated by confocalmicroscopy.

315Comparative Effectiveness of AnteriorCervical Diskectomy and Fusion withMinimally Invasive Posterior CervicalForaminotomy for Cervical RadiculopathyJeffrey A. Steinberg, John W. GermanIntroduction: Patients with cervicalradiculopathy are often treated witheither anterior cervical diskectomy andfusion (ACDF) or more recentlyminimally invasive posterior cervicalforaminotomy (miPCF). To date thecomparative effectiveness of theseprocedures has rarely been reported inthe literature. Traditional surgical dictumhas suggested that patients with axialpain may benefit from fusion.Methods: A retrospective review wasundertaken of 48 patients undergoingeither a miPCF (n=28) or ACDF (n=20) forthe treatment of cervical radiculopathy.Medical records were abstracted fordemographic information, medicalhistory, surgical details, andcomplications. Clinical outcomes wereassessed by patient derived neck and armvisual analog scores (VAS), neck disabilityindex (NDI), SF-12, and patientsatisfaction index (PSI). Outcomes wereanalyzed using both a threshold methodin which outcomes were classified assuccess (NDI<40; VAS<4.0) or failure(NDI>40; VAS>4.0) as well as the peri-operative change in which outcomeswere classified as success (NDI=-15;VAS=-2.0), or failure (ODI<-15; VAS<-2.0).Statistical analyses included a t-test forcontinuous variables and a Chi squaretest for categorical variables withsignificance set at p<0.05.Results:The groups did not differ atbaseline with respect to neck VAS, armVAS, neck to arm VAS ratio, NDI, or SF-12PCS, while the baseline SF-12 MCS(miPCF: 47.21 ± 13.50; ACDF: 36.75 ±10.95; p<0.05) did differ. At last follow-upthe mean peri-operative changes werenot significantly different for neck VAS,arm VAS, NDI, SF-12 PCS or SF-12 MCS.At last follow-up the per cent of patientswith a successful outcome as defined bythreshold criteria was significantly higherin the miPCF group than the ACDF groupfor neck VAS, arm VAS, and NDI.Conclusion: In this small retrospectiveanalysis miPCD is associated with asimilar degree of neck pain and disabilitythan that of ACDF. This conclusion runs

counter to that suggested by traditionaldictum.

316Accuracy of Percutaneous Pedicle ScrewPlacement Using the O-ARMMultidimensional Surgical ImagingSystem Compared with FluoroscopyJohn K. Houten, Rani Nasser, Nrupen Baxi,Michael Schiraldi, Adesh TandonIntroduction: Increasing popularity ofminimally invasive surgery (MIS) forlumbar fusion has led to dependenceupon intraoperative fluoroscopy forpedicle screw placement, as limitedmuscle dissection does not fully exposethe bony anatomy necessary fortraditional, freehand techniques nor forthe registration steps in image-guidancetechniques based upon preoperative CTscans. This has raised concerns about thecumulative level of radiation exposure forboth surgeon and OR staff, especially forsurgeons who perform MIS frequently.The recent introduction of the O-ARMMultidimensional Surgical ImagingSystem promises to allow superioraccuracy of pedicle screw placementwithout the need for fluoroscopy. Wepresent the first clinical series of whollypercutaneous screw placement using theO-ARM without fluoroscopy andcompare the results with placement withfluoroscopy.Methods: A retrospective review of a 14-month period identified 76 consecutivepatients that underwent minimallyinvasive lumbar fusion surgery by a singlesurgeon. Indications for fusion werespondylolisthesis, recurrent discherniation and/or severe facetarthropathy. The O-ARM was introducedin the middle of this period and was usedfor all subsequent patients. There were notraining cases. Accuracy of screwplacement was assessed by examinationof axial computed tomography.Results:The fluoroscopy group included113 screws in 31 patients, and the O-ARMgroup included 158 in 45 patients Theperforation rate involving medial pediclewall was 1.9% in the O-ARM group and10.6% in the fluoroscopy group (p<0.025).The overall pedicle perforation rate was12.7% verses 19.5%, with 86% ofperforations under 2mm. Noreoperations were necessary.Conclusion: Percutaneous pedicle screwplacement with the O-ARMMultidimensional Intraoperative ImagingSystem is a safe and effective techniquethat limits radiation exposure to surgeonand OR staff. Use of the O-ARM resultedin fewer medial wall breaches compared




with conventional fluoroscopictechniques in this single-surgeon series.

317Longterm Outcome After UnilateralApproach for Bilateral Decompression ofLumbar Spinal Stenosis: 9-YearProspective StudyYunus Aydin, Halit Çavusoglu, Ahmet Murat Müslüman, Okan Kahyaoglu, Osman Nuri TürkmenogluIntroduction:The aim of our study is toevaluate the results and effectiveness ofbilateral decompression via a unilateralapproach in the treatment ofdegenerative lumbar spinal stenosis.Methods:We have conducted aprospective study to compare themidterm outcome of unilaterallaminotomy with unilateral laminectomy.One hundred patients with 269 levels oflumbar stenosis without instability wererandomized to two treatment groups:unilateral laminectomy (Group 1), andlaminotomy (Group 2). Clinical outcomeswere assessed with the OswestryDisability Index (ODI) and Short Form 36Health Survey (SF-36). Spinal canal sizewas measured pre- and postoperatively.Results:The spinal canal was increased to4 6.1-fold (mean 5.1 ± SD0.8-fold) thepreoperative size in Group 1, and 3.3 5.9-fold (mean 4.7 ± SD 1.1-fold) thepreoperative size in Group 2. If theanteroposterior diameter of the spinalcanal (APD) (defined bone structure) wasnormal, laminotomies provided adequatedecompression. If the APD was reduced,laminectomies provided more adequatedecompression. If the transversediameter and APD were normal,removing the hypertrophic ligamentumflavum alone provided adequatedecompression. The mean follow-uptime was 9 years (range 7 10 years). TheODI scores decreased significantly inboth early and late follow-up evaluationsand the SF-36 scores demonstratedsignificant improvement in late follow-upresults in our series. Analysis of clinicaloutcome showed no statistical differencesbetween two groups.Conclusion: For degenerative lumbarspinal stenosis unilateral approachesallowed sufficient and safe decompressionof the neural structures and adequatepreservation of vertebral stability,resulted in a highly significant reductionof symptoms and disability, andimproved health-related quality of life.

318Neurological Outcome Following Nerve-Sparing Resection of Benign Pre-SacralNeurogenic TumorsMarie-Noëlle Hébert-Blouin, Daniel Leonard, Eric J. Dozois, Robert J. SpinnerIntroduction:Nerve sheath tumorsrepresent 5 to 10% of presacral tumors.The majority of these tumors are benign,slow growing, and cause minimal or ill-defined symptoms. As a result, diagnosisis often delayed; tumors may reachconsiderable size, and may involvesurrounding structures/organs makingtheir management complex. Dataregarding the surgical management andoutcomes of pelvic neurogenic tumorsare limited. The aim of this study was toevaluate the occurrence of postoperativeneurological deficit and/or clinicalsymptoms of urogenital or anorectaldysfunction after surgical nerve-sparingresection of benign presacral neurogenictumors.Methods: A retrospective review wasperformed of patients who underwentnerve-sparing resection of benignneurogenic presacral tumors between2004 and 2010 by the same experiencedteam of colorectal and peripheral nervesurgeons. Clinical, imaging and operativedata as well as postoperative functionaloutcome (neurological, urogenital andanorectal) were analyzed.Results: Eighteen patients (16 - 71 yearsof age) were included in the study. Twelveof these tumors were schwannomas and6, neurofibromas. The tumor size wasbetween 3.4 and 13.4 cm (largestdiameter). Thirteen patients presentedwith symptoms, 9 of these with motor,sensory, urogenital and/or anorectaldysfunction. All underwent anintracapsular nerve-sparing approach.There was no intraoperative complicationapart from blood loss (100cc to 3000cc,median of 600cc). Postoperatively, onepatient developed a prolonged ileus,ARDS, and an extensive DVT and anotherpatient a significant foot drop whichimproved to normal within a few months.Fourteen patients had improvement orresolution of their preoperativesymptoms or remained withoutsymptoms, 1 had persistence of thepreoperative symptom, 2 had newsymptoms, and 1 did not have adequatefollow-up.Conclusion: A nerve-sparing approach byan experienced team of surgeons allowssafe resection with high rate ofpreservation of the neurological functioneven in large tumors.

319Spinal Cord Intramedullary PressureIncreases in Thoracic Kyphotic Deformity:A Cadaveric StudyChad W. Farley, Bradford Curt, David B. Pettigrew, Jeffrey R. Holtz, Charles Kuntz, IVIntroduction: Previous studies revealthoracic T4-T12 kyphosis ranges from +14to +69 degrees for 98.5% of theasymptomatic adult population. Wesought to determine if spinal cordintramedullary pressure (IMP) changes inresponse to increasing thoracic kyphosis.Methods: In eight fresh-frozen cadavers, aprogressive kyphotic deformity wascreated. Cadavers were positioned, sittingwith skull clamp, and segmentallyinstrumented from occiput to L2. The T3lamina was removed, dura opened, and 3pressure sensors were advanced caudallyto T4/T5, T7/T8 and T11/T12 within thecord parenchyma. A step-wise kyphoticdeformity was induced by sequentiallyreleasing and retightening the skull clampwhile distracting posterior short segmentrods and closing anterior segmentalosteotomies. Lateral radiographic T4-T12Cobb angles and IMP measurementswere obtained.Results:Minor IMP increases of 2-5 mmHg were observed at one or more spinalcord levels in 1 of 8 cadavers when theCobb angle <+51° and in 4 of 8 cadaverswhen >+51° and <+65°. At Cobb anglesexceeding +65°, IMP progressivelyincreased at one or more levels in 7 of 8cadavers. There was no statisticallysignificant correlation between vertebralcanal diameter and IMP at maximumkyphosis suggesting canal diameter isunlikely to explain IMP variance. ForCobb angles >+51° and <+65°, statisticallysignificant minor increases in IMP weredetected at the T7/T8 level only (p = 0.02).For Cobb angles >+65°, statisticallysignificant increases in IMP weredetected at all three spinal cord levels (p <0.005).Conclusion:Thoracic kyphosis less than+51° resulted in no meaningful increasein IMP while kyphosis measuring +51° to+65° resulted in minor 2-5 mm Hgincreases. As the thoracic kyphoticdeformity exceeded +65°, IMP increasedsignificantly. IMP may help explain thewide range of “normal” thoracicalignment and further define thoracickyphotic deformity.




320MIS TLIF Reduces Adjacent SegmentDegenerationSanjay S. Dhall, Praveen V. MummaneniIntroduction: In comparison withtraditional Open TLIF, minimally invasiveTLIF’s limit muscle and facet exposure.Does such a limited exposure decreaseadjacent segment disease? No prior studyhas examined this issue. Weretrospectively compared our mini-openTLIF with our open TLIF patientsfocusing on the incidence of adjacentsegment disease.Methods: From 2003-2006, 39 patientsunderwent TLIF for DDD orspondylolisthesis. 18 patients underwentmini-open TLIF and 21 patientsunderwent open TLIF. The mean age ineach group was 54 years, and there wasno statistically significant difference inages between the groups (p=0.98). Mid-term follow-up was conducted todetermine the rate of symptomaticadjacent segment disease in each group.Modified Prolo Scores (MPS) wererecorded.Results:No patients were lost to follow-up, and mean follow-up was 3 years. Allpatients in both groups had successfulfusion confirmed by dynamicradiographs. In the open group, 3 patients(14%) developed adjacent segmentdisease requiring revision fusion surgery.None of the mini-open patients requiredrevision surgery.Conclusion:Mini-open TLIF allows formore muscle and facet sparing than openTLIF and may be associated with a lowerrate of surgical adjacent segment diseaseat three years.

321Supplement of High Magnesium DietsPromote Nerve Regeneration by Down-Regulated Inflammatory ResponseHung-Chuan PanIntroduction: Supplement of magnesiumeither pre-injury or post-injurysignificantly improved functionalrecovery in various neurologicaldisorders. However, the essential benefitsof magnesium supplement in peripheralnerve disorders have not been elucidatedyet. In this study, we investigate the effectand mechanism of magnesiumsupplement on peripheral nerveregeneration in a sciatic nerve crushinjury model.Methods: Peripheral nerve injury wasinduced in ICR mouse by crushing leftsciatic nerve using a vessel clamp. Beforeanimals subjected to nerve injury, the

animals were supplemented with dieteither of basal, low and high magnesiumdiets for 3 weeks. After injury, the animalswere supplemented with the same dietsfor another 4 weeks. Neurobehavior,electrophysiological and regenerationmarker were conducted to assess nerveregeneration. The deposits ofinflammation cells, the associated pro-inflammatory cytokines and genesexpression, and cell apoptosis markerswere used to investigate the mechanismof magnesium supplement.Results:Magnesium supplementsignificantly increased the concentrationof magnesium in the plasma as well as innerve tissue and Mg depletion producedthe reciprocal effect. The mostsignificantly improved neurobehaviorand electrophysiology study wereobserved in group treated with highmagnesium diet. The escalatedregeneration demonstrated either inneurofilament or S-100 expression alsoshowed the same trends. Increasedregeneration paralleled the reduceddeposits of inflammatory cells,expression of inflammatory cytokines,and associated macrophage migrationgenes. Furthermore, reduced Schwanncells apoptosis were in line withsignificant expression of bcl-2, bcl-XL anddown-regulated the expression of caspase-3 and cytochrome C.Conclusion: Administration of high Mgdiet before and continuously after injuryrescued Schwann cells from apoptosis bysuppressing the inflammatory response.These anti-inflammatory effectsparalleled the significant improvement inneurological function.

322Fusion Results Using DBM and BMA ineXtreme Lateral Interbody Fusion (XLIF)W.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:This study determines theviability of a graft composite composed ofdemineralized bone matrix (DBM)coupled with bone marrow aspirate(BMA) and local bone (LB) in use with theXLIF procedure.Methods: 91 patients underwent XLIFusing a graft composite composed ofdemineralized bone matrix (DBM), iliaccrest bone marrow aspirate (BMA),allograft chips, and local bone harvestedfrom the central vertebral body. Fusionwas defined as definitive, uninterruptedbridging of mineralized bone across theinterbody space and no significantmotion on flexion-extension radiographs.Results: 56 patients (24M; 32F; Avg 61.6

yrs; Avg BMI 29.9; 44 1LVL; 11 2LVL, 13LVL; LOS 1.68 days; 0 infections) wereavailable for follow-up 12 months aftersurgery. VAS pain scores improved from8.50 to 1.82. Disk height improved from6.4 preop to 10.3mm postoperatively andwas 9.2 mm at 12 months. Listhesis (34pts) improved from 4.21 preop to 0.64mm at 12 months. Modified Lenke scoreswere 2.1 (3 mos), 1.2 (6 mos), 1.1 (12mos). No patient had a pseudarthrosis bymotion criteria and none has been re-explored.Conclusion:The combination of a DBM-BMA-allograft-local bone compositecontained within PEEK spacers 56/56patients at 12 months postoperatively.Little has been reported about fusionrates in MIS procedures but thiscombination achieved fusion resultscomparable to earlier literature reportsfor Autograft or BMP in posterior oranterior lumbar fusions without theincumbent expense and documentedcomplications.

323Comparison of Clinical and RadiologicalFindings in Adjacent Segment DiseaseAfter Lumbar Fusion with TotalLaminectomy and Subtotal LaminectomyKyoung Suok Cho, Sang Bok Lee, Pil Woo Huh, Do Sung Yoo, Tae Gyu Lee,Chun Kun ParkIntroduction: Fusion has become thestandard of care for numerous pathologicconditions of the spine over the past 50years. The development of pathology atthe mobile segment next to a lumbar orlumbosacral spinal fusion has beentermed adjacent segment disease.Initially reported to occur rarely, it is nowconsidered a potential late complicationof spinal fusion. The purpose of thisretrospective clinical study was tocompare the incidence and radiologicalfindings of adjacent segment disease(ASD) after lumbar fusion with upperlumbar total laminectomy or subtotallaminectomy.Methods:Over a 12-year period, weperformed posterior lumbar fusion withtotal laminectomy (Group I) in 81patients and lumbar fusion with subtotallaminectomy in 80 patients. Patients werefollowed a minimum of 5 years (mean 7.5years). Radiographic changes in the discheight and vertebral slip range of motionwere measured. On magnetic resonanceimaging (MRI), postoperative progressionof the disc degeneration and spinal canalstenosis were evaluated.Results: Significant posteriorintervertebral instability (> 3mm) on




radiograph was more frequent in theGroup I (16.3 % vs. 6.3%, P <0.05). MRIimages demonstrated more significantaggravation of disc degeneration (36.5%vs. 16.6%, P <0.001) and progression ofadjacent stenosis (19.85 vs. 10%, P <0.01),at fusion upper disc level in the Group I.Conclusion: These results demonstratedan effect of fusion upper level soundinterspinous ligament and subtotallaminectomy for the prevention oftransition syndrome in lumbar spinefusion.

324Outcomes Following Minimally InvasivePosterior Cervical Decompression forMyelopathyJeffrey A. Steinberg, John W. GermanIntroduction: To date a comparativeanalysis of clinical outcomes following aminimally invasive posterior cervicalapproach (miPC) for myelopathy has notbeen compared to that of an anteriorcervical diskectomy or corpectomy withinterbody fusion (ACDF).Methods: A retrospective review wasundertaken of 64 patients undergoingeither a miPCD (n=32) or ACDF (n=32) fortreatment of myelopathy. Medical recordswere abstracted for demographicinformation, medical history, surgicaldetails, and complications. Clinicaloutcomes were assessed by patientderived neck and arm visual analogscores (VAS), neck disability index (NDI),and patient satisfaction index (PSI).Modified Japanese OrthopedicAssociation (mJOA) myelopathy scoresand Nurick (N) scores were classified asimproved (mJOA +3; N+1), same (mJOA+2 to -2; N 0), or worse (mJOA -3; N-1).Neck pain and disability outcomes wereanalyzed using a threshold in whichoutcomes were classified as success(NDI=40; VAS=4.0) and failure (NDI>40;VAS>4.0) as well as the peri-operativechange in which outcomes wereclassified as success (?NDI=-15; ?VAS=-2.0), and failure (?NDI<-15; ?VAS<-2.0).Statistical analyses included t-test forcontinuous variables and Chi square forcategorical with significance set at ap<0.05.Results: At last follow-up a successfuloutcome based on change criteriafavored miPCD for mJOA (miPCD: 45%;ACDF: 17%; p<0.05), N (miPCD: 50%;ACDF: 30%; p<0.05), and NDI (miPCD:39%; ACDF: 17%; p<0.05) while neck VAS,right arm VAS, and left arm VAS did notdiffer between the groups. At last follow-up the percent of patients obtaining asuccessful outcome based on threshold

criteria did not differ with respect to: neckVAS, right arm VAS, left arm VAS, or NDI.The PSI for both procedures was high(miPC: 4.00 ± 1.19; ACDF: 3.76 ± 1.30; NS).Conclusion: In this small retrospectiveanalysis miPCD is associated with similaroutcomes to that of ACDF. Furthercomparative effectiveness study of thesetechniques is warranted.

325Minimally Invasive Tumor Decompressionfor Spinal MetastasesHarshpal Singh, Scott A. Meyer, Zachariah Maliakal George, Arthur L. Jenkins, IIIIntroduction: Patients deemed pooroperative candidates for open surgerydue to age, comorbidities, metastaticburden, or limited life expectancy withneurologic compromise may benefit froma palliative decompression through aminimally invasive transpedicularapproach.Methods: An IRB approved retrospectivereview of 24 consecutive minimallyinvasive tumor decompressions on 14adult patients with symptomatic epiduralcompression during a 5-year period from2003 to 2008 was performed. Inclusioncriteria were patients with symptomaticepidural metastatic compression deemednot appropriate for open surgery becauseof age, burden of metastatic disease, orlife expectancy of less than 1 year basedon Tokuhashi scores. Exclusion criteriaincluded patients with significant spinaldeformity or evidence of instability, lifeexpectancy greater than 1 year, andhighly radiosensitive tumors. Medicalrecords and radiographic studies of thepatients were reviewed retrospectively.Patients were characterized according totheir age, gender, histopathology,radiographic findings, and treatmentoutcomes. Neurologic outcome wasgraded by preoperative and postoperativeKarnofsky scores and ambulation scores.Changes in ambulation scores andKarnofsky scores were assessed using theWilcoxon Signed Rank test on thedifferences between the pre-op and post-op scores for each surgical procedure.Results: Karnofsky performance statusscores improved from a preoperativemean of 57.1 to a postoperative mean of73.8, leaving a mean improvement of 16.6points. The median change (difference =postop - preop) was 15 and the Inter-Quartile Range (IQR) for the changes was5 - 20. This difference was significant(p=0.0001). Mean ambulation scoresimproved 1.1 points from a meanpreoperative score of 2.8 to a mean

postoperative score of 3.9. The medianchange (difference = postop - preop) was1 and the IQR for the changes was 0 - 2.This difference was significant(p=0.0001).Conclusion: Minimally invasivetranspedicular tumor decompression canimprove neurologic outcomes in patientsdeemed to be poor surgical candidates.

326Predictors of Back Pain and DisabilityFollowing Minimally Invasive Surgery forLumbar RadiculopathyAnthony G. Conte, John W. GermanIntroduction: Persistent back pain anddisability limits clinical outcomefollowing surgery for lumbarradiculopathy. Identification of the riskfactors associated with a poor outcomemay help improving outcome.Methods: A retrospective review wasundertaken of 140 patients undergoingsurgery for lumbar radiculopathy.Medical records were reviewed and datawas abstracted for demographics, pastmedical, past surgical, co-morbidities,anatomic factors, and intraoperativefactors. Six month outcomes wereavailable for patient derived outcomesincluding Oswestry disability index (ODI)and back visual analog score (VAS).Outcomes were analyzed using the peri-operative change in which outcomeswere classified as success (ODI>-15;VAS>-2.0) or failure (ODI<-15; VAS<-2.0)as well as a threshold method in whichoutcomes were classified as success(ODI<40; VAS<4.0) or failure (ODI>40;VAS>4.0).Results: Using the change method the percent of patients who were classified asfailures was 44.6% for ODI and 48.5% forback VAS while the threshold methodclassified treatment failures in 46.2% forODI and 35.8% for back VAS. A bivariateanalysis of the ODI perioperative changemethod identified the following riskfactors for failure: depression, anxiety,absence of sequestrectomy, absence ofannulotomy, and absence of PLL incision.Bivariate analysis of the ODI thresholdmethod identified the following riskfactors for failure: depression, anxiety,neurologic co-morbidity, foraminotomy,absence of annulotomy, and worker’scompensation. Bivariate analysis of theback VAS threshold method identified thefollowing risk factors for failure: femalesex, depression, anxiety, neurologicalcomorbidity, higher estimated blood loss,absence of sequestrectomy, and absenceof annulotomy. Bivariate analysis of theback VAS perioperative change method




suggests identified the following riskfactors for failure: depression,foraminotomy, and absence ofsequestrectomy.Conclusion:The common risk factors forpersistent back disability identified bythese analyses are: depression, anxiety,and absence of annulotomy. Thecommon risk factors for persistent backpain are depression and absence ofsequestrectomy.

327Idiopathic Spinal Cord HerniationUlrich Batzdorf, Langston T. HollyIntroduction: Idiopathic Spinal CordHerniation (ISCH) is a relatively rare buttreatable cause of neurologicaldysfunction.Methods:Ten patients with ISCH weretreated by the authors between 1986 and2010. Patient age ranged from 23 to 57years, with a mean of 51.5 years. The cordherniation was situated in the upperthoracic spine, between T3 and T7, andwas ventral or ventro-lateral in allpatients. Lower extremity sensoryimpairment and weakness with orwithout spasticity, were the mostcommon clinical presentations. Thediagnosis was established by magneticresonance imaging or computerizedtomographic scanning followingmyelography in all patients. All patientswere treated surgically. In some patientsthe cord herniation was noted to extendbeyond the margins of the dural defect,necessitating enlargement of the duralopening to release the cord. Using eitherbovine pericardium or synthetic material,a ventral sling was placed between thecord and the dural defect. The sling wasthen anchored to the patient’s dura andan expansile duraplasty was performed in5 patients. This technique was used in allbut the first of the ten patients. We did notresect any of the herniated cord tissue.Results: All patients improved aftersurgery, but one patient developedneuropathic pain requiring medicaltreatment. Lower extremity weaknessshowed most improvement, sensorysymptoms improved in half of thepatients, spasticity tended to remainunchanged. Aside from 2 patients treatedwithin the last year, the mean follow-uptime was 5 years.Conclusion: Although uncommon, thediagnosis if ISCH is still frequentlyoverlooked by both neurosurgeons andradiologists, resulting in delay ofdefinitive treatment. In most patients theappearance of ISCH on imaging studies issufficiently characteristic to establish the

diagnosis. The cause of this disorder iscurrently not known.

328Application of in Vivo Bioluminescence toMonitor Spine Tumor Volume in a RodentModel of Spine TumorRachel Sarabia-Estrada, Camilo A.Molina, Ziya L. Gokaslan, Timothy F.Witham, Jean-Paul Wolinsky, Ali Bydon,Daniel M. SciubbaIntroduction: Animal models ofmetastatic spinal tumors (ST) are used todetermine efficacy of spine surgery,radiation, and chemotherapeutics inpreclinical studies. Although tumorvolume (TV) can be measured viapathological analysis, there is currentlynot a highly specific imaging modalitythat can correlate neurological functionwith TV in rodents while are still alive. Weintroduce the application of abioluminescence imaging (BLI) wherebytumor volume can be non-invasivelymeasured and correlated withneurological function in a rat model ofmetastatic epidural spinal cordcompression.Methods:Human prostate cancer cellline (PC-3) that express luciferase; wereinjected subcutaneously into the flank ofsix athymic male rats to evaluate thedevelopment of tumors. Luciferin wasinjected at (40 mg/kg), andbioluminescence was imaged in theflank. The size was monitored every 3days. When the tumor reached a size of12x12 mm, it was removed and implantedinto the L6 vertebral body (7 x 7 mmpiece) via a transperitoneal approach.Tumor-implanted animals werefunctionally assessed daily via akinematic analysis of locomotion, anddysfunction was correlated withcomputed tomography (CT) andbioluminescence imaging.Results: 15 days after the cell injection therats develop tumors that reached a size of12x12 mm, and BLI showed proliferativeactivity of PC3 cells in the rat flank. Themorphology of the PC3 tumor wasconfirmed by histological analysis. ST wasthen detected by CT 23 days after tumorimplantation. Kinematic analysis oflocomotion was correlated with tumorgrowth.Conclusion:This study involves theapplication of a non-invasive in vivoimaging modality of TV in a rat model ofST. As CT does not adequately image softtissue and magnetic resonance imaging(MRI) is not cost effective, this techniqueshows reliable and accurate assessmentof TV correlated with both neurological

decline and postmortem pathologicalanalysis.

329Cost Effectiveness of TransforaminalLumbar Inter-body Fusion (TLIF) forGrade I Degenerative SpondylolithesisOwoicho Adogwa, Scott Parker, Alexandra Paul, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirtIntroduction:Transforaminal lumbarinter-body fusion (TLIF) forspondylolithesis-associated back- andleg-pain is associated with improvementin pain, disability, and quality of life.However, given the rising healthcare costsassociated with spinal fusion procedures,the cost-effectiveness of TLIF has recentlybeen questioned. In a single cohort cross-over study, we set out to prospectivelyassess the comprehensive costs of TLIF, todetermine its relative utility compared tothe preceding 6-12 months ofconservative therapy, and determine itscost-effectiveness in the treatment ofdegenerative spondylolithesis.Methods: Forty-five patients undergoingTLIF for grade I degenerativespondylolithesis-associated back- andleg-pain after 6-12 months ofconservative therapy were included. Two-year total back-related medical resourceutilization, missed work, and health-statevalues [quality adjusted life years(QALYs), calculated from EQ-5D with U.S.valuation] were assessed,Table 1. Two-year resource use was multiplied by unitcosts based on Medicare nationalallowable payment amounts (direct cost).Patient and care-giver work-day losseswere multiplied by self-reported gross-of-tax wage rate (indirect cost). Total cost perQALY gained after TLIF was assessed asincremental cost-effectiveness ratio(ICER: COSTSurg/QALYSurg - QALYMed).Results:Compared to health statesreported after 6-12 months of medicalmanagement, a significant improvementin all outcome measures was observedtwo years after TLIF(Figure 1), mean two-year gain of 0.86 QALYs per patient.Post-TLIF resource utilization is given inTable 1. Mean±SD total two-year cost ofTLIF was $36,835±11,800 (Surgery cost:$21,311±2,800; Outpatient resourceutilization cost: $3,940±2,720; Indirectcost: $11,584±11,363), Table 2. Whencompared to utility gained after 6-12months of medical management, TLIFwas associated with a mean two-yearICER of $42,854 per QALY gained.Conclusion:TLIF improved pain,disability, and quality of life in patientswith degenerative spondylolithesis-




associated back and leg pain. Whencompared to the preceding 6-12 monthperiod of medical management, the ICERof TLIF was <$50,000 per QALY. Thissuggests that TLIF is a cost effectivetreatment of lumbar spondylolithesiswhen evaluated with medicare costs.These results support the need forhealthcare policy and resource allocationin favor of spinal fusion procedures.

330Ten-Year Experience with the DakotaKnife Carpal Tunnel ReleaseCharles Joseph Miller, Wilson T. Asfora,Bryan J. WellmanIntroduction:The Dakota Knife is arefinement of the traditional opentechnique for carpal tunnel release. Wedescribe the Dakota Knife technique andreport more than ten years’ experience.Methods:The procedure is performedunder local or regional anesthesia. Loupemagnification is used. A 1.5cm mid-palmar incision is made. Retraction of thepalmaris fibers allows for layer-by-layerincision through the transverse ligamentuntil a small portion of the median nerveis exposed. The Dakota Knife is passedonce distally and once proximally. Fullrelease is verified visually and withpalpation. Wound closure is done withabsorbable or monofilament nylonsutures. A small wrap is applied. Splintsor casting is not necessary. We undertooka retrospective chart review on allpatients undergoing carpal tunnel releaseusing the Dakota Knife. Patients werefollowed from preoperatively to 30months following surgery. Patientquestionnaires were used for datacollection at 1, 3, 6, 18, and 30 months.Results: 461 procedures were performedon 328 patients from March 1998 toAugust 2010. Clinical findings werereported for all patients. Preoperativeclinical data is presented in tables 1 and2. Clinical results are reported in table 3.Numbness, whether residual or increasedwas reported in 8.3% of patients.Satisfaction is reported for 215 patientswho returned surveys at 18 and/or 30months. Results are reported in table 4.Conclusion: In the current group ofreported patients we experienced norecurrent nerve injuries, and there wereno surgical issues due to instrumentfailure. No hemostasis issues wereencountered. The patient outcomesreported were acceptable and consistentwith recently reported outcomes(1). TheDakota Knife (figures 1 and 2) is designedto cut the ligament as the instrument ispassed, thereby greatly reducing or

eliminating the volume of instrumentbeneath the ligament and by extension,the amount of pressure exerted on thealready compromised median nerve. Thetechnique is easily learned with aminimal learning curve and a few simplenuances in technique.

331Location Dictates Major SurgicalComplications for IntraduralExtramedullary Spinal TumorsAnkit Indravadan Mehta, Isaac Karikari,Allan H. Friedman, Carlos A. Bagley,Robert E. IsaacsIntroduction: Intradural extramedullary(IDEM) neoplasms can pose a challengefor surgical resection. Numerous factorsaffect the resectability and ultimately theoutcome for these lesions. We report ourinstituational experience with surgicalresection of intradural extramedullaryneoplasms, focusing on the effect oflocation on surgical outcomes.Methods:We performed a retrospectivereview of 98 consecutive patients rangingfrom 7 to 87 years old (mean age 49.9years) who presented with an intraduralextramedullary spine tumor in thecervical and/or thoracic regions andunderwent resection between February2000 and July 2009. All patients hadmagnetic resonance imaging (MRI) andthe axial location of the tumor wascategorized as anterior, posterior, orlateral. Additionally, the spinal cord at therespective level of resection was analyzed.Postoperative complications wereassessed, as well as the neurologic statusat the patient’s last follow-up clinic visit.Results: Surgery related complicationrates amongst patients with IDEM spinaltumors based on axial spinal cordlocation was found to be 41.6% of allanterior tumors (n=12), 4.4% of all lateraltumors (n=69), and 0% of all posteriorlocated tumors (n=17). Although nostatistical difference was noted in thefrequency of tumors occurring at anyparticular level in the spine (p=0.98),major surgery related complications were4.5% at O- C3 (n=22) , 0% at C4 -C7(n=16), 23.7% at T1-T4 (n=21), 5% at T5-T8 (n=20), and 0% at T9-T12 (n=20).Complication included CSF leakrequiring lumbar drainage, reexplorationfor epidural hematoma, and majorpostoperative neurological deficits. Majorpostoperative neurological deficits wereseen in 3 patients, all had anterior locatedtumors. All major neurological deficitsoccurred from T1-T5, where 2 of 21patients or 9.5% with T1-T4 tumors and 1of 20 or 5% of those with T5-T8 tumors

experienced a complication.Conclusion: Spinal intraduralextramedullary (IDEM) tumors that areanteriorly located in the upper thoracicspine were found to have the highest rateof surgery related major complications.This finding might be associated with theunforgiving anatomy of the upperthoracic spine with a higher cord to canalratio, as well as the tenuous vascularsupply to that region of the spinal cord.

332Interpedicular Travel in the HumanLumbar Spine Instrumented with Rigidand Semi-Rigid Rods: Implications forDynamic FusionBrandon G. Chew, Diana Jho, Daniel Cook, Donald M. Whiting,Jonathan B. Bellotte, Boyle C. ChengIntroduction: Posterior dynamic fusionconceptually provides adequatestabilization of an instrumentedfunctional spinal unit while allowingsufficient motion to facilitate arthrodesis.The Scientx Isobar TTL Evolution is adynamic posterior fusion system thatwhen used in conjunction with ananterior column interbody fusion graftintentionally allows for greateranterior/posterior column load sharingand axial distraction with bending.Methods:The biomechanical propertiesof the Isobar system were tested utilizinginstrumented cadaveric lumbar spinesplaced in a six degree-of-freedom testingapparatus. Pedicle displacement betweenadjacent instrumented vertebrae, definedas interpedicular travel (IPT), wasascertained in three different Isobarconfigurations (low, middle, and high) aswell as with a rigid rod underflexion/extension, lateral bending, axialtorsion and compression loads. Axial roddisplacement was used as a proxy for IPTand was determined by the attachment of4 LED mounted flags to the superior andinferior aspects of each rod.Displacement of the LEDs was measuredin all three axes using an opto-electronicarray.Results:With the Isobar damper in themiddle position, there was a statisticallysignificant increase in IPT in flexion andextension compared to the rigid rod. Themean difference of displacement wasfound to be 0.080mm, 95% CI of 0.018 to0.142 (p=0.017). There was a statisticallysignificant increase in IPT in lateralbending with the Isobar damper in thehigh position compared to the rigid rod. Amean difference of displacement was0.342mm, 95% CI of 0.039 to 0.645(p=0.030). Data analysis included one-




way repeated measures ANOVA andbonferroni post hoc test. Statisticalsignificance was set to p<0.05.Conclusion: The Isobar damper in themiddle position allowed for greaterchange in rod length with flexion andextension than the rigid rod. In the highposition, the Isobar damper allowedgreater lateral bending compared to therigid rod.

333Single Level Lumbar Fusion at L5-S1: AComparison of MIS TLIF and AxiaLIFW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction: Results of the MIS-T/PLIFprocedure were compared with AxiaLIFprocedure to contrast safety andeffectiveness of each minimally invasivetranssacral fusion alternative.Methods: Data were collected on the first50 patients (25MIS-T/PLIF, 25AxiaLIF)treated by a single center for single-levelfusion at the LS junction using twoalternative MIS techniques. The first 25patients (11M, 14F, age 48.9 yrs, BMI 30.3)were treated with MIS-T/PLIF and thesecond 25 (13M,12F; age51.4 yrs, BMI31.4) with AxiaLIF. Outcomes arereported, including 12 and 24 monthpostop data (MIS-T/PLIF group n=19,5;AxiaLIF group n=17,5.Results: In the MIS T/PLIF group, ORtime averaged 102.8 minutes,hemoglobin change 2.10g, and length ofstay 1.69 days. Disk height increased3.0mm from preop to postop with 1.1mm settling at 12 and 24 months; listhesis(10 pts) decreased 1.8mm from preop topostop with maintenance of reduction at12 and 24 months; Lenke scoresmeasured 2.9 at 3 months, 1.6 at 12months, and 1.3 at 24 months. VASimproved from 8.1 to 3.0 postop and was3.0 and 0.8 by 12 and 24 months. Therewere four complications in this group:one deep infection, one brokeninstrument (radial disk cutter) requiringanterior removal, one neuropraxia, andone transfusion. One patient died ofunrelated causes at 3 months postop. Inthe AxiaLIF group, OR time averaged 68.8minutes, hemoglobin change 1.74g, andLOS 0.92 days. Disk height increased to7.6mm at postop with 0.8mm settling by12 months and 24 months; listhesis (17pts) decreased 2.2mm with loss ofreduction of 0.6mm at 12 months and0.8mm at 24 months; Lenke scoresmeasured 2.9 at 3 months, 2.1 at 12months, and 1.8 at 24 months. VASimproved from 8.7 to 3.7 at 3 months, 2.7at 12 months, but declined to 4.4 at 24

months. There were no complications inthis group.Conclusion:We saw similar clinical andradiographic outcomes but different ORtimes, blood loss, and length of stay. Theprevalence of complications in the MIS-T/PLIF group led us adopt the AxiaLIF asfusion method of choice at L5-S1 interval.

334Extreme Lateral Interbody Fusion (XLIF)in the Morbidly ObeseW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction: Minimally invasiveprocedures are challenging in obesepatients whose body habitus maydecrease the accessibility of the spine tothe instruments necessary to performthese procedures. The XLIF procedure,however, is performed in the lateraldecubitus position, minimizing thedifficulty of the pannus as it falls awayfrom the exposure.Methods: In our single-site prospectiveseries of 941 XLIF patients, 479 wereidentified as obese (BMI>30) and 160 ofthose were morbidly obese (BMI>38).Comorbidities, surgical details, hospitalstay, complications, pain scores, changesin disk height and alignment, and fusionwere assessed.Results: In all our XLIF patients, nosurgery could not be successfullycompleted due to body habitus. Theheaviest patient to date weighed 427 lbs.(193.7 kgs); the largest BMI was 61.8 (avg43.6, range 38.0-61.8). Age ranged from22-78 years. Comorbidities includedsmoking (30%), prior spine surgery (43%),diabetes (30%), CAD (42%), COPD (4%).586 levels were treated in these 479patients: 386 1-levels, 80 2-levels, 12 3-levels and 1 4-level; the majority at L4-5.All but 2 surgeries included supplementalfixation. There was three transfusions andone infection. Complications included 2MI’s at 4 and 6wks, one atrial fibrillation,pneumonia requiring intubation for 5days, one other respiratory distressrequiring re-intubation, one pulmonaryembolism, one posterior hardwarefailure/rod fracture at 6 months, and onefracture of vertebral osteophytesrequiring reoperation. Hospital stayaveraged 1.29 days. From pre-op to 24month follow-up: disk height increasedan average 2.6mm; slip decreased anaverage 3.2mm in spondylolisthesispatients; and VAS pain scores decreasedfrom 8.7 preop to 2.7 at 24 months. Lenkescores were 2.1 at 3 months, 1.2 at 12months, and 1.1 at 24 months.Conclusion: Our results demonstrate the

usefulness and safety of the XLIFtechnique in treating morbidly obesepatients minimally invasively.Complications are minimal, procedurestimely, and outcomes similar to non-obese patients.

335Impact of Multi-modality IntraoperativeMonitoring During Correction ofSymptomatic Cervical or CervicothoracicKyphosisPaul Park, Anthony C. Wang, Shawn Hervey-Jumper, Frank La MarcaIntroduction: Surgical correction ofsymptomatic cervical or cervicothoracickyphosis involves the potential forsignificant neurologic complications.Intraoperative monitoring (IOM) hasbeen shown to reduce the risk ofneurologic injury in scoliosis surgery.IOM has not been well-evaluated duringsurgery for cervical or cervicothoracickyphosis. In this article, we review acohort of patients who underwentkyphosis correction with multi-modalityintraoperative monitoring (MIOM).Methods: Twenty-nine patients wereincluded in this study. Preoperative andpostoperative Cobb angles weremeasured to determine extent ofcorrection. MIOM consisted ofsomatosensory evoked potentials(SSEPs), transcranial motor evokedpotentials (TcMEPs), andelectromyography (EMG). Sensitivity,specificity, positive predictive value(PPV), and negative predictive value(NPV) were assessed for each monitoringmodality.Results: Mean patient age was 58.0 years,and 20 patients were female. Meanpreoperative and postoperative sagittalCobb angles were 41.3° and 7.3°,respectively. A total of 8 intraoperativemonitoring alerts were observed. TcMEPsyielded a sensitivity of 75%, specificity of84%, PPV of 43%, and NPV of 95%. SSEPshad sensitivity of 25%, specificity of 96%,PPV of 50%, and NPV of 88%. EMGresulted in sensitivity of 0%, specificity of93%, PPV of 0%, and NPV of 96%.Changes in TcMEP led to successfulintervention in 2 cases. There was onecase where a C8 palsy occurred withoutany changes in MIOM.Conclusion: Specificity and NPV weregenerally high in all 3 monitoringmodalities in contrast to sensitivity andPPV. Both false positive and false negativeresults occurred. TcMEP monitoring wasthe most useful modality and appeared toallow successful intervention in certaincases. Larger prospective, comparative




studies are necessary to determinewhether MIOM truly decreases the rate ofneurologic complication and is thereforeworth the added economic cost andintraoperative time.

336Comparison of Three-DimensionalFluoroscopy vs. Postoperative ComputedTomography for the Assessment ofAccurate Screw Placement AfterInstrumented Spine SurgerySarah T. Garber, Erica Bisson, Meic SchmidtIntroduction:Three-dimensional (3-D)fluoroscopy performed intraoperativelyhas been used increasingly as a means toevaluate screw placement during spinalinstrumentation. While 3-D fluoroscopydoes not possess the resolution andimage quality of a computed tomography(CT) scan, it may provide adequateinformation about screw placement thatcan guide both intra- and postoperativedecision making. The goal of this researchproject is to compare the accuracy ofvisualization of proper screw placementdetermined intraoperatively using 3-Dfluoroscopy with postoperative CT.Methods: A retrospective review of allspinal instrumentation procedures doneat the University of Utah by the seniorauthors using the O-arm was completed.Cases in which no postoperative CT wasdone were excluded. All screws wereassessed for placement on both the O-arm and CT images using thepreviously described method by Rao, et al.Results:Twenty cases were identified thathad both post-instrumentation O-armimages and postoperative CT images.These included 8 cervical, 4cervicothoracic, 2 thoracic, 3thoracolumbar, and 3 lumbosacral cases.Forty-five, thirty-six, and twenty-twoscrews were placed in the cervical,thoracic, and lumbosacral spine,respectively. The O-arm identified a totalof 13 breaches (11-grade 1, 2-grade 2),and the CT identified 14 breaches (10-grade 1, 3-grade 2, 1-grade 3).Conclusion:The results of our study showthat intraoperative three-dimensionalfluoroscopy is highly accurate in theevaluation of screw placement duringneurosurgical spine procedures. Theseresults should lead to a decreasedfrequency of postoperative CT scans andtherefore help to minimize both cost andradiation exposure in patients whorequire spinal instrumentation.

337Axial Rotation Requires Greatest Load inMultifidus Muscle: Potential Associationwith Low Back Pain?Bruce Robie, Sebastian Dendorfer, John Rasmussen, Soren TorholmIntroduction:The multifidus muscle is akey stabilizer of the spine[1]. Its atrophyhas been shown in patients with low backpain[2] and those with herniations[3],possibly due to overload. Motions andloads that could induce overload are notwell understood. The AnyBody ModelingSystem™ simulation software enablesmuscle force analysis and contains morethan 1000 individual muscle branches,and includes a validated lumbar spinemodel[4,5] (Fig. 1). The purpose of thisstudy is to examine the force required bythe different branches of the multifidusfor each of the principal motions.Methods: Flexion-extension, lateralbending and axial rotation of the lumbarspine using a model of a standing humanunder influence of gravity was assessed.The stiffness of each lumbar spinalsegment was based on published cadavermeasurements. The analyzed parameterswere the forces in all branches of themultifidus muscles on the right side ofthe spine.Results:The peak force in a multifidusbranch occurred during axial rotation(53N), with lesser forces in flexion/extension (20N) and lateral bending(17N). The multifidus force peaked at thelimit of axial rotation (12° of lumbar spinerotation) and diminished towards zero inthe opposite direction (Fig. 2), while amaximum force was seen at full flexionwitha lesserpeakat extension andreduced forces at neutral position.Conclusion: Axial rotation motioninduced the largest force in themultifidus, which is a key stabilizingmuscle of the posterior spine. This resultis consistent with previous work showingthat axial rotation motion induces thegreatest load on the facets[6] andexcessive axial rotation motion occurs inpatients with low back pain[7]. Thecurrent study is limited to an analysis ofnormal behavior; further study of themultifidus in disease states is warranted.

338Evaluation of Neurological Dysfunction inRat Animal Models of Spine TumorsRachel Sarabia-Estrada, Camilo A. Molina,Ismael Jimenez-Estrada, Ziya L. Gokaslan,Timothy F. Witham, Jean-Paul Wolinsky,Ali Bydon, Daniel M. SciubbaIntroduction: Animal models of spinal

tumors serve as the foundation for manypreclinical studies regarding efficacy ofspine surgery, radiation, andchemotherapeutics. The standardevaluation of neurological spinal corddysfunction in rodents is the BBB (Basso,Beattie, Bresnahan) scale. Unfortunately,this scale is complex and requiressignificant personnel training to obtainreliable grading. We introduce theapplication of a video-assisted kinematicsystem to evaluate gait impairment in arat model of metastatic epidural spinalcord compression.Methods: 12 Fisher rats (Group 1) wereimplanted with CRL-1666 tumor in the L6vertebral body. 6 rats (Group 2)underwent sham surgical procedureswith no placement of tumor. All animalswere functionally assessed daily via akinematic analysis of locomotion. Theiliac crest, hip, knee, ankle, and the fifthmetatarsal phalangeal joints were markedwith ink. Unrestrained gaits of both shamand experimental animals were recordedwith a digital video camera on atransparent acrylic passageway. Limbcoordinates consisting of 3 to 4 stepcycles were analyzed frame by frameusing the Image J software. Locomotionkinematics was studied and evaluatedusing the software “walking rats”.Results: Line drawings were constructedbetween articulation joints to illustratethe spatio-temporal sequences ofhindlimb movements during gait. Swingand stance phases were identified fromeach step cycle. Swing and stance phaseduration and both length and stridespeeds were determined for both groups.Conclusion:This study involves theapplication of an objective andquantitative evaluation of progressivelyparetic rats using video analysis of gaitkinematics through a transparentwalkway. Complication of datasets hasallowed standardization of gait in normalanimals and progressively pareticanimals that can be applied to spinetumor and other spinal cord injurymodels in rodents.

339A Role for Motor and SomatosensoryEvoked Potentials During AnteriorCervical Discectomy and Fusion forPatients Without Myelopathy: Analysis of57 Consecutive CasesRisheng Xu, Eva Ritzl, Matthew J. McGirt,Daniel M. Sciubba, Jean-Paul Wolinsky,Timothy F. Witham, Ziya L. Gokaslan, Ali BydonIntroduction: Although the usage ofcombined motor and sensory




intraoperative monitoring has beenincreasing and has been shown toimprove the surgical outcome of patientswith cervical myelopathy ormyeloradiculopathy, the role oftranscranial electric motor evokedpotentials (tceMEP) used in conjunctionwith somatosensory evoked potentials(SSEP) in patients presenting withradiculopathy but without myelopathyhas been less clear.Methods:We retrospectively reviewed allpatients (n=57) with radiculopathy butwithout myelopathy undergoing anteriorcervical decompression and fusion at asingle institution over the past 3 yearswho had intraoperative monitoring withboth tceMEPs and SSEPs. The data wereanalyzed with regards to intraoperativeSEP or tceMEP changes, as well as intra,peri, or postoperative clinicallysignificant events and outcomes.Results: 57 (100%) patients presentedwith radiculopathy, 53 (93.0%) withmechanical neck pain, 35 (61.4%) withmotor dysfunction, and 29 (50.9%) withsensory deficits. 30 (52.6%) were male,and the average age was 47.6±11.1. Anaverage of 1.65 vertebral levels (range 1-3)was fused. Intraoperatively, 3 (5.3%)patients experienced decreases in SSEPsignal amplitudes, and four (6.9%) hadtceMEP signal changes. There were threeinstances where a change inneuromonitoring signal requiredintraoperative alteration of the surgicalprocedure: these were deemed clinicallysignificant events/true positives. SSEPmonitoring showed 2 false positives and 2false negatives, whereas tceMEPmonitoring only had one false positiveand no false negatives. Thus, tceMEPmonitoring exhibited higher sensitivity(33.3% to 100%), specificity (95.6% to98.1%), positive predictive value (33.3% to75.0%), negative predictive value (97.7%to 100%), and efficiency (91.7% to 98.2%)compared to SSEP monitoring.Conclusion: Although recent studies havepresented evidence to support the use oftceMEP monitoring along with SSEPs inhigh risk patients with central cordcompromise, none have systematicallyexamined the utility of usingtceMEP/SSEPs in patients withoutmyelopathy. Here, we present a series of57 patients undergoing anterior cervicaldecompression and fusion forradiculopathy without myelopathy,where combined tceMEP/SSEPmonitoring resulted in an intraoperativechange in surgical procedure in 3 (5.8%)patients, likely preventing irreversibleneurologic damage.

340Single Level Lumbar Fusion for a Grade Iand II Spondylolisthesis Correction Usingthe AxiaLIF Rod SysyemW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction: AxiaLIF offersspondylolisthesis correction and sparethe facet joint and surroundingligamentous tissues to the spinal column,thus providing superior stability to theslipped segment. In addition, thedirectional vector of placement of theintervertebral device facilitates reductionof the listhetic segment. Herein, we reportour early results using this approach as analternative to conventional lumbarfusion. To our knowledge, this representsthe first report of the use of this techniquein spondylolisthesis.Methods: 85 patients (36 M, 49 F, age 54.5yrs, BMI 32.0) were treated with AxiaLIFfusion at L5-S1 for either a Grade I (n=69)or Grade II or greater (n=15)spondylolisthesis. The VAS scores, discheights, and improvement in slip andcomplications are presented.Results:VAS improved by 65% over thefirst year; disk height increased 3.6 mmfrom preop to postop (with some settling(1.34 mm) by 24 months); listhesis wasreduced by 3.6 mm at postop, but settledby 2.7 mm at 24 months. There were noneural or visceral injuries, or hardwarefailures. Two patients had mild gapping ofcoccygeal incisions that were treated withlocal dressings and resolved, two patientshad graft herniations requiringlaminotomy, one patient had pneumoniatreated with IV antibiotics, one patienthad delirium, one patient had aninfection, one patient requiredtransfusion, and two patients developed anonunion that was revised at 13 and 24months respectively.Conclusion: A transsacral MIS approachusing the AxiaLIF fixation system at L5-S1for a Grade I or Grade II spondylolisthesisoffers a safe, reproducible alternative totraditional open procedures. Thisapproach provides adequate reduction ofa Grade I or II spondylolisthesis. Theintermediate results demonstrateencouraging clinical outcomes with anacceptable complication rate. However,the areas of graft herniation, disc heightsettling, listhesis settling, and fusion ratesbear watching. Of greatest concern is thedifficulty assessing fusion status (>45%are not definitely fused) and the loss ofdisk height (29.5%) and listhesisreduction (19.2%) noted 12 months aftersurgery.

341A Retrospective Clinical Study of “Hybrid”Anterior 3- or 4-level CervicalDecompression and Fusion Technique ToAddress Multi-level Cervical SpondyloticMyelopathy and/or RadiculopathyPaul K. Edwards, Kelli Bunton, Aditya Ancha, John M. SmallIntroduction: A retrospective clinicalstudy to assess fusion and outcomes ofpatients undergoing a “hybrid” anteriorcervical 3- or 4-level decompression andfusion technique to address multi-levelcervical spondylotic myelopathy orradiculopathy. This technique consists ofa single-level anterior corpectomy withPEEK (polyetheretherketone) or titaniumcage placement and adjacent 1- or 2-leveldiscectomy with PEEK interbody cagereconstruction and anterior cervicalplating.Methods: From 2004 - 2009, fifty patientswere treated with the “hybrid” technique.Cervical flexion/extension radiographswere reviewed to assess fusion (mean 37months). Lordosis correction wasmeasured by C2-C7 cobb angles on thepre- and postoperative lateralradiographs. Pre- and postoperative VASand SF-36 scores were recorded. Thecorpectomy provided local bone graftand was supplemented with DBM ifneeded. No patient required harvest ofiliac crest bone.Results:Two patients (4%) hadsymptomatic non-unions and hadposterior fusion with instrumentation atthe involved level(s). Mean pre- andpostoperative C2-C7 sagittal angle were2.6 and 13 degrees of lordosis,respectively. Mean 10.4 degrees oflordotic correction obtained. 37% ofpatients had a preoperative kyphoticsagittal plane deformity. VAS and SF-36(both PCS & MCS component) scoresimproved an average of 3.4 and 8 points,respectively.Conclusion:Using the “hybrid”technique to address multi-level cervicalspondylotic myeloradiculopathy providesreliable fusion rates (96%), eliminates themorbidity associated with posteriorsupplemental fixation, and demonstratesa low revision rate (4%). Another benefitto this technique is the substantialamount of autograft available withcorpectomy, subsequently eliminatingthe need for iliac crest bone graft. Inaddition to these benefits, the anteriorreconstruction allows for excellentcorrection, as well as maintenance, ofcervical lordosis. This technique alsoshowed improvement in both SF-36




components (MCS & PCS) and VASoutcome scores similar to those seenusing other accepted techniques.

342Is Facet Fusion BiomechanicallyEquivalent to Posterolateral Onlay Fusion?Kevin T. Foley, Jeffrey M. Toth, Lawrence Lenke, Mei Wang, Howard B. Seim, III, A. Simon TurnerIntroduction:Clinically, a facet fusion isless invasive, requires less bone graftharvest, and is associated with lessmorbidity than a posterolateral fusion(PLF) using autograft. However, it is notknown if the biomechanical stiffness of afacet fusion is equivalent to thebiomechanical stiffness of a PLF.Methods: In order to evaluate fusionefficacy in the instrumented ovinelumbar spine model, eight sheep had 10cc/side of iliac crest bone graft (ICBG) forPLF at L2-L3. 0.5 cc/side ICBG was placedfor facet fusion at L3-L4. 0.5 cc/siderhBMP-2/ACS (0.43 mg/mL) was placedfor facet fusion at L4-L5. Sheep wereeuthanized at six months. Unconstrainedbiomechanical testing was performed ina non-destructive manner on the L2-L3and L4-L5 levels. All spinal levels wereanalyzed using undecalcified histology.Results: As seen in the graph, the PLfusion with ICBG and the rhBMP-2 facetfusion treatment groups demonstratedsimilar stiffness, with the rhBMP-2 facetfusion group having on average slightlyhigher stiffness in all six loadingdirections. The only difference betweenrhBMP-2_Facet and the ICBG_PLF thatreached the level of statistical significancewas the stiffness in extension (p<0.01,Bonferroni/Dunn test). All eight levels inthe rhBMP-2/ACS facet fusion treatmentgroup and all eight levels in the autograftfacet fusion treatment groupdemonstrated bilateral histologic fusion.Six of sixteen rhBMP-2/ACS treated facetdefects demonstrated small intraosseoushematomas or seromas. 4/8 levels in theautograft PLF treatment groupdemonstrated a bilateral histologicfusion. 1/8 demonstrated a bilateralhistologic non-fusion. 3/8 showed aunilateral fusion.Conclusion: Both rhBMP-2/ACS andautograft demonstrated 100% efficacywhen used for facet fusion in this ovinemodel. Biomechanically, the PL fusionwith ICBG and the rhBMP-2 facet fusiontreatment groups demonstrated similarstiffness in all six loading directions, withthe rhBMP-2 facet fusion group havingon average slightly higher stiffness in alldirections.

343Measurement of Anterior Column LoadSharing in Posterior Dynamic FusionDevicesAlexander Kwong-Tak Yu, Joseph Kyle Hobbs, Zachary G. Wright,Daniel Cook, Jonathan B. Bellotte, Donald M. Whiting, Boyle C. ChengIntroduction: Posterior dynamic fusiondevices have become of interest becausethey not only stabilize the pathologicfunctional spinal unit, but may facilitatearthrodesis more than traditional rigidrod devices. Wolff’s law states that normalphysiologic loads facilitate bone growthvia mechanotransduction, an adaptiveprocess which translates physiologicstress into effector-cell responses byosteoblasts, resulting in bone formation.We compared anterior column loadsharing between dynamic and rigid rodfusion devices under physiologicbiomechanical forces with thepresumption that anterior column loadsharing can translate into facilitatedarthrodesis.Methods: Six fresh frozen human lumbarcadaveric specimens were stripped of softtissue except for osteoligamentousstructures. Anterior column load sharingwas tested at the L3-L4 level using amodified transforaminal lumbarinterbody fusion (TLIF) cage spacer withan integrated load cell. Load sharing wastested under axial compression (0N to150N), flexion-extension bending, lateralbending and axial torsion (± 7.5 Nm).Treatment modalities compared include:destabilized spine (no instrumentation,left facetectomy), rigid rod stabilization,and dynamic stabilization using IsobarTTL Evolution. Results:Under axial compression, thedynamic stabilization treatment with thedampener between pedicles showed astatistically significant increase inanterior column load sharing (69.2N, 19.6SD) when compared to the rigid rod(40.6N, 23.3 SD) stabilization (p=0.024).The destabilized spine treatment showeda statistically significant increase inanterior column load sharing (83.9N, 10.6SD) when compared to rigid rodtreatment (p=0.018). No significantdifferences were noted among the othermodalities and load types.Conclusion:Under axial compression,the load experienced by the anteriorcolumn appears to be greater utilizingdynamic fusion systems than traditionalrigid rod systems. This increased loadmay translate into improved and fasterrates of arthrodesis of the pathologic

functional spinal unit in the clinicalsetting.

344DBM Use in 2-Level PLIFS: FusionComparison of Smokers and Non-smokersW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:Of our single-siteconsecutive series of 110 two-level PLIFpatients, 47 smoked at the time ofsurgery. Clinical and radiographicmeasures were prospectively collectedand evaluated to assess comorbidities,complications, and fusion results at 12and 24 months postop.Methods: 110 instrumented, 2-level PLIFprocedures were performed by a singlesurgeon using a graft composite wereprepared from ground lamellar bone,supplemented with DBM and posterioriliac crest bone marrow aspirate (BMA).The composite was placed in the apertureof PEEK or machined allograft spacers (toachieve interbody fusion) and along theintertransverse membrane (to achieveposterolateral fusion). Anteroposteriorand lateral flexion and extensionradiographs, obtained at three-, six-, andtwelve-months, were evaluated utilizingLenke’s criteria for intertransverse fusionand modified Lenke criteria of interbodyfusion. Global fusion was defined as either:Lenke or modified Lenke score of 1; orLenke score 2+modified Lenke score 2.Results: 46 smokers and 62 non-smokers,ranging in age from 33-85 years (averageage= 57.42 years) presented for 12-monthfollow-up. Intertransverse/interbodyscores for smokers=1.89/1.20 and fornon-smokers=1.69/1.25. To date, 32smokers and 40 non-smokers havepresented for 24 month follow-up. Lenkescores for smokers at 24 months postopwere 1.81/1.25; non smokers 1.63/1.18.Similar complication rates were observedin both groups; 6 re-operations wereperformed for adjacent segment disease.Conclusion: Smoking is often identifiedas a contributing factor to increasedpseudarthrosis (non-union) rates inspinal fusion surgeries. The fusion ratesfor smokers and non-smokers were 97.8%and 98.4% at 12 months respectively, and97% and 97.5% at 24 months; nosignificant difference was shown betweenthe two groups. Slightly better(intertransverse) Lenke scores were notedin the nonsmokers.




345Rate of Fusion of Interbody Constructs inTwo-Level PLIFs Using a CommerciallyAvailable DBMW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction: In our single-siteprospective series of xxx two-level PLIFpatients, 56 had the PEEK interbodydevice, and 46 had the Allograft device.Clinical and radiographic measures wereevaluated to assess complications andfusion at 12 and 24 monthspostoperatively.Methods: 110 patients underwent 2-levelinstrumented PLIFs. Patients wereassigned to one of two treatment armsthat included a composite of DBM + BMA+ LBt hat was placed in the aperture ofpolyethyletherketone (PEEK) spacers(n=56) or the medullary canal ofmachined fibular allograft wedges (n=46)prior to being implanted in the interbodyspace. Anteroposterior and lateralflexion/ extension radiographs wereevaluated utilizing a modified Lenkescoring. Fusion was defined asuninterrupted bridging bone across theinterbody space without motion on theflexion-extension radiographs.Results: 107 of 110 patients, with averageage of 57.6 years (range from 32 to 85years) presented for follow-up at 12months. 98.3% of PEEK patients and94.3% of allograft patients wereconsidered fused. Of the 72 patients whohave presented for 24 month follow-up todate, 100% of PEEK patients and 93.9% ofthe Allograft group were consideredfused. Noted complications include:infection (n=3), wound disruption (n=2),pneumonia (n=1), pulmonary embolus(n=1), and dural tear (n=1); 6 reoperationswere performed for adjacent segmentdegeneration.Conclusion:The results indicate excellent12-month and 24-month fusion rates inboth cohorts. We believe that it is easier toassess PEEK graft incorporation, whichmight account for the different fusionrates between the two groups.

346A Comparison of Two-Level LumbarFusions Using Minimally Invasive (XLIF)vs. Open (PLIF)W.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:Multi-level pathology hasin the past precluded minimally invasivesurgical techniques due to therequirements for greater exposure toachieve results comparable to traditional

techniques. The XLIF approach providesaccess to multiple lumbar levels throughsmall lateral incisions and retroperitonealdissection, minimizing approach-relatedmorbidity while providing anteriorcolumn access for large graft placement,excellent disk height and alignmentrestoration, and indirect decompression.Methods: In our single-site consecutiveseries of 941 XLIF patients, 155 had 2-level treatment for multiple indications(stenosis, scoliosis, post-decompressioninstability, DDD, and/orspondylolisthesis). Clinical andradiographic measures wereprospectively collected and evaluated. Aretrospective database of 109 2-level openPLIF patients from the same practicewere evaluated for the same measures asa basis of comparison.Results: Patient demographics weresimilar in both groups. All XLIF surgerieswere quick and uneventful. All includedminimally disruptive posterior fixation. Inthe XLIF group, there were notransfusions or infections, with a meanhemoglobin change of 1.42; whilehemoglobin change in PLIF patientsaveraged 3.10. Hospital stay averaged 1.2days for XLIFs and 3.16 days for PLIFs.Lenke score of 89% of XLIF patients with12-month follow-up was 1, comparedwith 79% of PLIF patients at 12 months.While reoperation rate among XLIFpatients was 8% (10/117), there was a19% reoperation rate in the PLIF cohort.Conclusion:There is little in the literaturedescribing the use of minimally invasivetechniques for 2-level pathologies. In ourexperience, patients with multi-levelpathologies can expect the same benefitsand successful outcomes from this lessinvasive procedure as those with single-level indications. Moreover, the clinicaland radiographic outcomes in two-levelXLIF compare favorably to those usingmore traditional open techniques in thissingle-site series.

347Long-term Prospective Analysis ofMinimally Invasive Transforaminal LumbarInterbody Fusion and PercutaneousPedicle Screw PlacementMick J. Perez-Cruet, Girish K. Hiremath,Ramiro Perez de la Torre, David Cooley,Sophia Lang-PerezIntroduction:Minimally invasivetransforaminal lumbar interbody fusion(MITLIF) reduces approach relatedmorbidity. Long-term prospective patientoutcomes, progression of adjacent leveldisease and re-operation rates arelacking.

Methods: 94 patients underwent MITLIFwere followed prospectively for over 5years. Outcomes included: Visual AnalogScale (VAS), Oswestry Disability Index(ODI) and Short Form-36 (SF36)preoperatively and at postoperativeintervals.Results: Patients included 62 females and32 males average age 58 years treated forDDD with (n = 23) or without (n = 24)stenosis or spondylolisthesis with (n = 31)or without (n=16) stenosis. Levels fusedincluded: L5-S1 (n = 36), L4-5 (n = 40), L3-4 (n = 6), L2-3 (n = 4 ), or 2 level fusion (n= 8). Mean estimated blood loss andhospital stay duration were 177 cc and 3.3days, respectively. Mean ODI scoredeclined from 50.9% preoperatively to34.9% at 5 year follow-up (p < 0.003).Mean VAS score decreased from 7.4preoperatively to 3.0 at 5 year follow-up(p < 0.003). Dynamic radiographicsrevealed 98% fusion rate after 1 year. Nopatients had worsening of neurologicaldeficit. Surgical site infection rate was 1%.Clinically significant adjacent leveldegeneration requiring fusion was seenin 1 patients (1%) with previous openlaminectomy. No patients with primaryMITLIF required extension of fusionconstruct over the 5-year follow-upperiod.Conclusion:MITLIF maintainedexcellent outcomes with low long-termre-operative rates and adjacent leveldisease. The majority of patients onlyrequired singe level (91%) fusion toachieve significant clinicalimprovements.

348Occipitocervical Fixation: Long-TermFollow-up in Fifty-Seven PatientsJan Stulik, Zdenek Klezl, Jan Kryl, Petr NesnidalIntroduction:Occipitocervical fixationand spondylodesis is indicated in variouscases of occipitocervical instability.Methods: Between 1997 and 2007, a totalof 57 patients underwent occipitocervicalfixation (OC) there were 25 men and 32women, from 4 to 77 years of age. 2groups, group one - tying wires or cablesand group two - screw-rod or screw-platesystems. Indications included trauma in15, rheumatoid arthritis (RA) in 28,destruction due to psoriasis in one, tumorin eight, and congenital anomalies in fivepatients. The patients were evaluated at afinal follow-up ranging between 12 and132 months after the primary surgery(average, 42.7 months). Indications forsurgery and the method and extent ofinstrumentation were recorded. The




evaluation included pain andneurological deficit assessment,radiographic evidence of the stability offixation and bone union andintraoperative and early and latepostoperative complications.Results:Of the 57 patients, bone fusionwas the aim of surgery in 52. Five patientsdied of associated injuries or seriousmedical complications shortly after theoperation. Of the remaining 47, boneunion was achieved in 44 patients(93.6%). Pseudoarthrosis developed inthree patients who. In terms of boneunion, there was no difference between ashort (C0-C2) and a long (C0-CX or C-T)fixation. No differences among fixationmaterials were found. The differences inpercent bone union after spondylodesisbetween the tying-wire and screw-rodfixation systems were not statisticallysignificant (p>0.05). In the patientstreated for RA, psoriasis or congenitalanomaly, the Nurick scale scoresignificantly improved at 2 years aftersurgery (p<0.05). In comparison with theothers, the RA patients had a significantlyhigher number of complications (p<0.05).The patients treated for tumor showed asignificant difference between the pre-and postoperative VAS values (p<0.05).Conclusion: Rigid OC fixation is a veryeffective method for the treatment ofcraniocervical junction instability. Thecurrently used implants allow us toachieve high stability and efficiency ofbone union. Regardless of theinstrumentation used, fusion is achievedin more than 90%, and clinicalimprovement in more than 80% of thepatients.

349A Biomechanics Study Comparing theSubsidence of Three Different Designs ofCarbon Fiber Lumbar Interbody CagesUnder Direct Compression Loading inHuman Cadaveric SpinesFred Chiu-lai Lam, Ronald Alkalay,Michael W. GroffIntroduction:Unilateral transforaminaland direct lateral approaches are gainingpopularity compared to the traditionalbilateral posterolateral lumbar interbodyfusion technique. The posterolateralcorners of the endplates have beenshown to be stronger than the anteriorand central regions. We hypothesize thatsingle carbon fiber cages placedanteriorly or centrally may lead to moresubsidence compared to bilateral cagesplaced in the posterolateral quadrantsunder direct compression.Methods:The caudad surface of 28

human cadaveric spine segments from L3to L5 were potted in methymethacrylate.The superior endplates was exposed andthe segment was mounted in a hydraulicmaterial testing system. Specimens wereequally divided between four testinggroups: three styles of carbon fiber cages,one placed anteriorly, one placedobliquely, and two placedposterolaterally, as well as two titaniummesh cages placed centrally. Specimenswere subjected to compression untilfailure of the endplate was observed.Force-displacement curves weregenerated and regression analysis wasperformed to compare subsidence acrosscage designs as well as failure andstiffness characteristics of theintervertebral cage-bone interface.Results:There were no differencesbetween bone density across the testgroups. Each cage design demonstrated apre-failure response followed bysubsidence within the endplate and laterinto the vertebral body. The posterolateralcarbon fiber cages demonstrated thehighest yield and ultimate loads as well aspre-yield stiffness and subsidencestiffness, which was significant comparedto the titanium mesh cages and theoblique carbon fibre cage. The titaniummesh cages showed the highest degree ofsubsidence, compared to the carbon fibercages. None of the carbon fiber cagedesigns showed significant differences insubsidence compared to each other.Conclusion: Positioning on the endplatedoes not seem to significantly effectsubsidence for carbon fiber cagescompared to centrally placed titaniummesh cages.

350Patient Satisfaction with Spine Surgery: A Systematic ReviewRobert Partlow Naftel, Beverly C. Walters,Barton L. Guthrie, Mark N. HadleyIntroduction: Patient satisfaction is ameasurement reflecting patients’perception of outcome of care and hasbeen considered for use in futurereimbursement schemes. Amultidimensional, disease-specificpatient satisfaction instrument couldguide changes in surgical practice forquality improvement. No consensus onpatient satisfaction instruments exists inspine surgery. The goals of this review areto establish how patient satisfaction withspine surgery has been previouslymeasured, determine if there is a disease-specific, comprehensive instrument tomeasure patient satisfaction, and todefine the dimensions of care that

determine patient satisfaction in spinesurgery.Methods: A systematic search of threeonline databases, unpublished sources,and citations was undertaken to identify85 empirical studies reporting patientsatisfaction with spine surgery. Themanuscripts were reviewed for patientsatisfaction instrument used;instruments were categorized by contentand method axes as described previouslyin the literature. A taxonomy of patientsatisfaction with spine surgery identifiedthe major characteristics of providers andmedical care influencing patientsatisfaction and acted as a structure tocategorically define the dimensions ofpatient satisfaction in spine surgery.Validity and reliability of each instrumentwas assessed.Results: Studies used predominantlyglobal (66/85), rather thanmultidimensional (15/85), satisfactioninstruments (4 did not specify). The mostcommonly used multidimensionalinstrument was the Brigham SpinalStenosis Questionnaire (9/85). Moststudies (92%) reported satisfaction withoutcome rather than care. Sevendimensions of patient status, outcomeand care experience affecting patientsatisfaction were identified: pain,function, patientexpectations/preference, specific patienthealth characteristics, caregiverinterpersonal manner, efficacy/clinicaloutcomes, and postoperativecare/therapy.Conclusion: At present, no patientsatisfaction instrument exists that isdisease-specific and covers alldimensions of patient satisfaction inspine surgery. For quality improvement,such a disease-specific, comprehensivepatient satisfaction instrument should bedesigned, tested for reliability andvalidity, and widely implemented.

351Minimally Invasive Transforaminal LumbarInterbody Fusion for Spondylolisthesis inSignificantly Obese PatientsDarryl Lau, Paul ParkIntroduction: It has been shown thatobese patients undergoing traditionalopen spinal fusion for degenerativeconditions tend to have significantincreased risk of complications. Inaddition blood loss can be significantlyincreased as larger incisions are requiredin obese patients. Minimally invasivespinal fusion in overweight and obesepatients has been suggested to be safeand may offer potential benefits. This




study examines minimally invasivetransforaminal lumbar interbody fusion(MI-TLIF) for treatment ofspondylolisthesis in significantly obeseadults (BMI>35) compared to normaladults (BMI<25).Methods: Between 2006 and 2009,patients with a BMI>35 or BMI<25undergoing elective TLIF forspondylolisthesis were identified. UsingStudent t-tests and Fisher’s exact tests, weassessed the relation of blood loss,complications, hospital stay, andpostoperative outcomes (visual analoguescale (VAS) for pain and oswestrydisability index (OSW)) between the twogroups.Results: Seventeen (17) patients fit the setcriteria: 9 patients in the obese group(mean BMI of 37.4) and 8 patients in thenormal group (mean BMI of 23.4). Therewere no significant differences in bloodloss (p=0.341), complications (p=0.999),and hospital stay (p=0.579) between thetwo groups. Mean follow-up for the obeseand normal groups were 14.4 months and17.1 months, respectively. Both groupshad significant improvements in VAS(obese, p=0.002, and normal, p=0.004)and OSW (obese, p=0.002 and normal,p<0.001) at follow up after undergoingsurgery. There were no significantdifferences in postoperative VAS(p=0.717) and OSW (p=0.996) scoresbetween the two groups.Conclusion:With MI-TLIF, outcomeswere comparable with the advantage thatthere did not appear to be an increasedrate of complications, blood loss, orhospital stay in obese patients comparedto non-obese.

352The Effect of Minimally Invasive PosteriorCervical Approaches vs. Open AnteriorApproaches on Neck Pain and DisabilityJeffrey A. Steinberg, John W. GermanIntroduction:Traditional surgical dictumsuggests that patients with myelopathy orradiculopathy and significant axial painshould be treated with an anteriorinterbody fusion as a posteriordecompression alone may exacerbatetheir neck pain. To date the effect of aminimally invasive posterior cervicalapproach (miPC) on neck pain has notbeen compared to that of an anteriorcervical diskectomy or corpectomy withinterbody fusion (ACF).Methods: A retrospective review wasundertaken of 89 patients undergoingeither a miPCD (n=49) or ACF (n=40) forthe treatment of myelopathy orradiculopathy. Medical records were

abstracted for demographic information,medical history, surgical details, andcomplications. Clinical outcomes wereassessed by patient derived neck visualanalog scores (VAS) and neck disabilityindex (NDI). Outcomes were analyzedusing: 1) a threshold in which outcomeswere classified as success (NDI<40;VAS<4.0) or failure (NDI>40; VAS>4.0) and2) the peri-operative change in whichoutcomes were classified as success(?NDI=-15; ?VAS=-2.0), and failure(?ODI<-15; ?VAS<-2.0). Groups werecompared using Chi square tests withsignificance taken at p<0.05.Results: At last follow-up the percent ofpatients classified as successful using thethreshold criteria were as follows: neckVAS (miPC: 75%; ACDF: 70%; NS) andNDI (miPC: 71%; ACDF: 58%; NS). Thepercent of patients classified as successfulusing the peri-operative change criteriawere as follows: neck VAS (miPC: 55%;ACDF: 56%; NS) and NDI (miPC: 42%;ACDF: 23%; p<0.05).Conclusion: In this small retrospectiveanalysis miPCD is associated withsimiliar neck pain and disability than thatof ACF. Given the avoidance of cervicalinstrumentation and interbody fusion inthe miPCD these results suggest thatfurther comparative effectiveness study iswarranted.

353In Vivo Model of Cauda Equina VentralRoot InjurySamuel J. Mackenzie, Igor Smirnov, Blair CalancieIntroduction:Considering the highincidence of cauda equina damageamong cases of traumatic spinal injury(12-20%) and the absence of effectivetreatments, the cauda equina requiresdistinct study when it comes to motorinjury and repair. Model: We havedeveloped a model of cauda equinainjury in the rat that meets the followingrequirements: 1) level-specific andrepeatable identification of motor nerveroots enabling surgical axotomy; 2)exclusion of pre-existing innervation andlocal sprouting from intact (i.e.uninjured) motor neurons as causes ofrecovery, and 3) quantification offunctional deficits and recovery.Methods:Twenty-four female Sprague-Dawley rats were used in this set ofexperiments. Ventral nerve roots wereidentified using a method previouslydescribed by our lab, involving stimulus-evoked EMG in the proximal, middle, anddistal tail muscles. Ventral roots were thencut bilaterally at the third and fourth

sacral levels and the first coccygeal level.All rats were tested in a minimum of threefollow-up sessions that involvedstimulus-evoked EMG recording uponstimulation of the caudales nerves andvideo analysis. Retrograde staining withFluoro-Gold was performed directly afterthe final follow-up session. Rats wereperfused five days later prior to spinalcord sectioning and microscopy.Results:During initial surgery, 5.5±1.2cuts were made. Electrophysiological andbehavioral follow-up testing successfullyidentified cases where axotomy waseither complete or incomplete, as verifiedby Fluoro-Gold staining. In cases wherebilateral axotomy was complete, weobserved straight, flaccid paralysis of themiddle and distal tail and an absence ofmotor neuron staining at the spinal levelsinnervating those myotomes.Conclusion:We have developed a novelmodel of cauda equina injury in the rat.Future studies will examine motor nerveroot repair using a multi-faceted strategyinvolving conduits and mediators ofcellular injury. Preliminary data related toconduit-only repair are presented.

354Safety and Efficacy of rhBMP2 inPosterior Cervical Spinal Fusion forSubaxial Degenerative Spine Disease:Analysis of Outcomes in 204 PatientsRisheng Xu, Mohamad Bydon, Michael J. Dorsi, Matthew J. McGirt, Ziya L. Gokaslan, Ali BydonIntroduction:Currently, many studiesoffer excellent demonstration of BMP’sability to enhance fusion rates in anterioras well as posterior lumbar surgery. Morerecently, BMP has also been shown toincrease arthrodesis rates in anteriorcervical surgery, albeit with an increase incomplication rates. To date, few studieshave investigated the safety and efficacyof BMP use in cervical surgeriesapproached posteriorly.Methods:We retrospectively reviewed 204consecutive patients with degenerativecervical spinal conditions necessitatingposterior cervical fusion at a singleinstitution over the past 4 years. Theincidence of postoperative mechanicalneck pain, fusion rates, as well asneurologic outcomes were comparedbetween patients who received BMP vs.no BMP intraoperatively.Results: 134 (65.7%) patients presentedwith mechanical neck pain, 82 (40.6%)with radiculopathy, 157 (77.7%) withmotor weakness, 110 (54.5%) withsensory deficits, and 44 (21.9%) withbladder dysfunction. There were no




significant differences in preoperativevariables between the non-BMP vs BMPcohorts. Non-BMP patients were morelikely to receive demineralized bonematrix (p<0.0001) and allograft(p<0.0001), and BMP patients were morelikely to receive hydroxyapatite crystals(p<0.0001) for fusion. There were nosignificant differences in intraoperativeblood loss, vertebral levels fused, or ratesof incidental durotomy. Over an averagefollow-up of 24.2 months, there were nosignificant differences between the twocohorts in hospitalization length, CSFleakage, DVT, PE, hyperostosis, infection,pneumonia, hematoma, C5 palsy, wounddehicense, reoperation rates, orNurick/ASIA scores. 11 (7.1%) patients inthe non-BMP group experiencedinstrumentation failure vs. none in theBMP group. This approached but did notreach statistical significance (p=0.06).Patients receiving BMP had a significantlyincreased rate of fusion both via Chi-squared (p=0.01) and log-rank tests(p=0.02). However, patients receivingBMP also had the highest rates ofrecurrent/persistent neck pain via Chi-squared (p=0.003) and log-rank tests(p=0.01).Conclusion:We show that BMP usage inthe posterior cervical spine does notincrease complication rates, significantlyincreases arthrodesis rates, but also mayincrease the rate of recurrent/persistentneck.

355Adjacent Level Stress Following LongSegment Posterior CervicalDecompression and Fixation: An In-VitroHuman Cadaveric ModelRyan M. Kretzer, Wesley Hsu, Nianbin Hu,Hidemasa Umekoju, George I. Jallo, Paul C. McAfee, P. Justin Tortolani, Bryan W. CunninghamIntroduction:This study investigatedchanges in adjacent level stress followingposterior cervical decompression andfixation in order to define idealinstrumentation stopping points in thesurgical management of cervicalspondylotic myelopathy.Methods: Eight human cervicothoracicspines were evaluated under thefollowing conditions: 1) intact spine, 2)C3-C6 laminectomy alone and incombination with: 3) C3-C6 vs. 4) C3-C7fixation; 5) C3-C7 laminectomy alone andin combination with: 6) C3-C7, 7) C2-C7,8) C3-T2, vs. 9) C2-T2 fixation. Multi-directional flexibility testing utilized thePanjabi Hybrid Testing Protocol. Intactmoments of ±2.0Nm were used for

flexion-extension, axial rotation, andlateral bending, with quantification ofadjacent level range of motion (ROM)over three motion segments (C2-C3, C6-C7, and C7-T1) normalized to the intactspine (100%). Intradiscal pressures(IPs)were also measured at each level andare reported in PSI.Results: For the C3-C6 laminectomysubgroup, there were no significantdifferences in flexion-extension ROM orIP at C2-C3 or C7-T1 when comparingC3-C6 vs. C3-C7 fixation (p>0.05). Theextension of instrumentation to includeC7 provided a significant decrease in C6-C7 ROM (p<0.05). Following C3-C7laminectomy and sequentialreconstruction, the most significantincrease in C2-C3 flexion-extension ROMand IP was found in the C3-T2 subgroup[ROM: 348% of intact (p<0.05); IP:319±243 vs. 65±41 PSI intact condition(p<0.05)]. At C7-T1, the largest increase inflexion-extension ROM and IP was notedfollowing C2-C7 fixation [ROM: 531% ofintact (p<0.05); IP: 152±83 vs. 21±14 PSIintact condition (p<0.05)].Conclusion: For a C3-C6 laminectomy,construct extension to C7 significantlydecreases flexion-extension ROM/IP atC6-C7 without a significant increase inROM/IP at C2-C3 or C7-T1. For a C3-C7laminectomy, C3-T2 and C2-C7instrumentation resulted in the mostadjacent level ROM/IP at C2-C3 and C7-T1, respectively, so consideration shouldbe given to including both C2 and T2within these constructs.

356Subaxial Cervical Synovial Cysts: Reportof 35 Histologically Confirmed SurgicallyTreated Cases and Review of theLiteratureMark K. Lyons, Barry D. Birch, William E. Krauss, Naresh P. Patel, Eric W. Nottmeier, Orland K. BoucherIntroduction: Intraspinal extraduralsynovial cysts are found ventral to theligamentum flavum and arise from thefacet joint. These lesions are also reportedin the literature as juxtafacet cysts 1-7,ganglion cysts 1,8-19 , articular cysts20,intraosseous cysts21, epidural cysts22and ligamentum flavum cysts.23 Someauthors have argued that the termjuxtafacet cyst be preferred over synovialor ganglion cyst18, while others haveargued the opposite.1 In addition, somereports distinguish between synovialcysts (which are lined withpseudostratified columnar cellscontaining clear fluid) vs. ganglion cysts(which have a connective tissue capsule

without a mesothelial lining).3,24,25 Themost common term in the literature forthese lesions is synovial cyst.Methods: Between 1993 and 2009, 35patients with histologically confirmedcervical subaxial synovial cystsunderwent surgical resection. Weevaluated the clinical presentingsymptoms, neuroimaging studies,location of the synovial cyst, surgicaltreatment and outcomes of the patientbased upon a retrospective review ofpatient charts. The patient characteristicsare summarized in Table 1. There were 24males and 11 females. The mean age atpresentation was 69 years old (range 33-82). Twenty-two of the 35 patientspresented with cervical radiculopathy astheir initial complaint and 13 presentedwith myelopathy symptoms. The mostcommon location of the synovial cyst wasat C7/T1 (17), followed by C4/C5 (8);C3/C4 (5); C5/C6 (3); and C2/C3 (2).Results: Preoperative and postoperativeneurological assessments were done bystaff neurologists independent of theoperating surgeon. The mean follow-uptime was 49 months (range 12-134).Surgical outcomes were determinedusing the Modified Rankin Score (Table2).79 Twelve patients were scored 0 (nosymptoms); 17 patients were scored 1(performs all usual activities despitesome symptoms); 4 patients were scored2 (slight disability); and 2 patients werescored 3 (moderate disability).Conclusion:This series of 35 patientswith subaxial cervical synovial cystssurgically treated over a period of 17 yearsillustrates the relative rarity of theselesions. Patients presenting with cervicalradicular or myelopathic symptoms mayoccasionally be harboring a synovial cyst.Surgical resection and decompression ofthe neural structures is the optimaltreatment.

357Effect of Lumbar Disc Replacement onLumbosacral Lordosis in Patients withDegenerative Disc DiseaseManish K. Kasliwal, Harel DeutschIntroduction: Lumbar fusion is one of themost common surgeries performed byspine surgeons. There has been a growinginterest in total disc replacement for backpain with the rising concern of adjacentsegment degeneration. Fusion surgeryhas been shown to lead to decrease in thesacral tilt and lumbar lordosis which canaccount for post fusion pain resulting inless acceptable clinical outcome evenafter successful fusion. Lumbar discreplacement (LDR) has recently emerged




as an alternative treatment for back pain.There have been very few studiesreporting changes in lumbar sagittaloutcome after LDR. The present studyreports the effect of LDR on global andsegmental lumbar lordosis in group ofseventeen patients who underwent LDRat the author’s institution.Methods: Retrospective study ofradiographic data of 17 patients whounderwent LDR for single leveldegenerative disc disease at the author’sinstitution was performed. Studyincluded measurement of pre and postoperative segmental and global lumbarlordosis and angle of lordosis. Inclusioncriteria was a single level LDR surgery andavailability of pre and post op lateralupright x ray of the lumbar spine in all thepatients.Results: Patients age varied from 19 to 54(mean, 35) years. The mean segmentaland global lumbar lordosis before surgerywas 17.3 and 49.7 degrees whichincreased to 21.6 and 54 degrees aftersurgery (p< 0.001 and 0.03 respectively).Conclusion:The effect of LDR on sagittalbalance appears favorable with anincrease in global and segmental lumbarlordosis after single level LDR fordegenerative disc disease. The degree ofpost operative angle of lordosis was notaffected by the angle of implant chosen atthe operated level and variedindependently of the implant angle.

358Contact Pressure in the Cervical FacetJoint During Physiologic Sagittal Bendingof the SpineJoel A. Bauman, Nicolas V. Jaumard,Christine L. Weisshaar, Benjamin B. Guarino, William Charles Welch, Beth A. WinkelsteinIntroduction:The spinal facet joint isintegral to the normal function of thespine and can also contribute to thespine’s instability after trauma and/orsurgery. The contact pressure betweenthe joint’s articular surfaces provides ameasure of local joint mechanics and theloading environment to cartilage. Yet,presently there is limited data, largelyfrom computational models, definingcervical facet pressures during spinalloading.Methods:Cadaveric C2-T1 human spines(n=6) underwent 2.7Nm of flexion and2.4Nm of extension bending, acquisitionof vertebral motions and facet pressuresduring bending were measuredsynchronously. Contact pressure wasmeasured continuously during

application of the bending moment witha tip-mounted pressure probe insertedinto the C5/C6 facet joint via the C5lateral mass, using a technique thatpreserves the joint capsule’s mechanicalintegrity.Results:There were no differencesbetween flexion and extension for theglobal cervical spine (9.5±1.6 degrees)and C5/C6 segmental (1.4±0.6 degrees)rotations. Initial contact pressures in thefacet joint were similar in extension(1.4±0.9 psi) and flexion (1.5±2.1 psi).However, the change in pressureestablished over the application ofmoment was significantly greater(p=0.002) in extension (9.8±3.9 psi) thanin flexion (-1.5±1.4 psi). Pressure changeshad a greater linear correlation withapplied moment than with C5-6 motion,and with extension more than withflexion.Conclusion:This study is the first todefine contact pressures in the humancervical facet joint for physiologicloading. Results support the hypothesisthat contact pressure increases duringextension as the joint closes and isrelieved with its opening during flexion. Anegative change in pressure measured forflexion likely represents the relief ofminimal initial contact to complete lossof contact. The small pressure changesduring these physiologic bendingscenarios suggest this joint may be verysensitive to even subtle changes in itsloading environment. Support providedby Synthes, NREF, and the CatharineSharpe Foundation.

359Objective Quantification of ShoulderKinematics: Implications for PeripheralNerve Compression SyndromesJustin M. Brown, William E. Janes, Jack EngsbergIntroduction: Postural abnormalitiesincluding neck protraction, “roundedshoulders” and slumped thorax have allbeen found in association with upperextremity compression neuropathies,particularly when multiple sites ofcompression exist. Clinical observationssuggest that upper extremity movementpatterns are altered as well. Competingexplanations exist for the causalrelationship between kinematics andmulti-level nerve compression (MLNC)syndromes. That proximal nervecompressions resulting from alteredpostures and dynamics may predisposeto development of distal neuropathieshas been proposed. Conversely, distalnerve compression may have central

effects which lead to altered proximalpostures and kinematics. Therelationship cannot be elucidatedwithout defining these changes. With thesupport of the 2009 Larson Award, wehave developed methods for measuringshoulder kinematics using video motioncapture. This solution provides for precisedynamic kinematic evaluation of thethorax, head, scapulae and upperextremity throughout the range ofmotion.Methods:Three related investigationshave now utilized this method. First, thekinematics of healthy persons andpersons with MLNC were compared. Inaddition, healthy controls were evaluatedbefore and after transient“deafferentation” via either tourniquet-induced ischemia at the level of thehumerus or Lidocaine injection at thecarpal tunnel.Results: See Table 1 for results.Conclusion:We have demonstrated, forthe first time, quantifiable alterations inshoulder kinematics associated withMLNC. These results also suggest thattransient deafferentation of the distalupper extremity results in alteredshoulder kinematics. Although neitherintervention is a perfect model for MLNC,this suggests a mechanism whereby theproximal movement patterns describedin persons with nerve compressions maybe in part a result of, and not only acontributor to, the distal neuropathy.Ongoing research will attempt to furtherelucidate the effect of distal neuropathyusing interventions designed to augmentdistal afferent input to the spinal cord.

360A DBM, BMA, Local Bone Graft Compositein Multi-level PLIF: Fusion RatesW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:Data were collected for oursingle-site consecutive series of 110 two-level PLIF patients. Clinical andradiographic outcomes were evaluated toassess complications and fusion rates at12 and 24-month follow-up.Methods: 110 instrumented, 2-level PLIFprocedures were performed by a singlesurgeon using a graft composite preparedfrom ground lamellar bone,supplemented with DBM and posterioriliac crest bone marrow aspirate (BMA).The composite was placed in the apertureof PEEK or machined allograft spacers (toachieve interbody fusion) and along theintertransverse membrane (to achieveposterolateral fusion). Anteroposteriorand lateral flexion and extension




radiographs, obtained at three-, six-, andtwelve-months, were evaluated utilizingLenke’s criteria for intertransverse fusionand modified Lenke criteria of interbodyfusion. Global fusion was defined aseither: Lenke or modified Lenke score of1; or Lenke score 2+modified Lenke score 2.Results: 107 patients were evaluated at 12months, and 72 at 24 months to date.Intertransverse (Lenke) scores at 12months = 1.78 and interbody (modifiedLenke) scores = 1.22; at 24 months =1.71/1.21. Complications included:infections (n=3), wound disruption (n=2),pneumonia (n=1), pulmonary embolus(n=1), dural tear (n=1); 6 re-operationswere performed for adjacent segmentdisease. 105 patients were judged to befused; there were 2 nonunions.Conclusion: The DBM-local bone-BMAachieved fusion in 105/107 2-level PLIFsat 12 months postoperatively (70/72 at 24months). This combination achievedfusion results comparable to earlierliterature reports for autograft withoutthe incumbent expense and documentedcomplications of BMP.

361Socioeconomics of Degenerative CervicalSpine Disease in the United StatesAli A. Baaj, Tien V. Le, Fernando L. Vale,Juan S. UribeIntroduction: Degenerative cervical spinedisease constitutes a significant source ofmorbidity in the United States. A limitednumber of published, peer-reviewedreports detail and quantify thesocioeconomic burden of this entity on anational level.Methods: The Nationwide InpatientSample database was queried for themajor degenerative cervical spinediagnoses for the year 2007, including:Cervical spondylosis, cervical spondylosiswith myelopathy, cervical discdisplacement, cervical degenerativedisease, cervical disc disease withmyelopathy and cervical spinal stenosis.The NIS is maintained by the Agency forHealthcare Research and Quality (AHRQ)and represents a 20% random stratifiedsample of all discharges from nonfederalhospitals within the United States. It is thelargest all-payer inpatient care databasein the US and contains data fromapproximately 8 million hospital staysfrom 1000 hospitals each year. The NIS isthe only national hospital databasecontaining charge information on allpatients, regardless of payer, includingpersons covered by Medicare, Medicaid,private insurance, and the uninsured.

Data on demographics, length of stay,charges, discharge patterns and surgicalintervention were analyzed.Results: There were an estimated 164,630hospitalizations in 2007 for degenerativecervical spine disease in the US. Meanlength of stay was 2.3 days and meanhospital charge per admission was$41,562. The total national hospitalcharges for this entity exceeded 6 billionUSD in 2007. The 45-84 age groupconstituted the majority of the cases(75%) with an equal male:female ratio.87% of the hospitalizations wereassociated with routine discharges (asurrogate marker of good outcome). Anestimated 36% of all spinal fusions in2007 were related to degenerative cervicalspine pathology.Conclusion: Degenerative cervical spinedisease is not only a major source ofmorbidity, but also accounts forsignificant healthcare utilization withinthe spinal disorders. Efforts to promoteresearch in this area as well as to advancesafe and cost-effective treatmentmodalities need to continue.

362Does Radiographic Location DictatePathology of Intradural ExtramedullarySpine Tumors?Ankit Indravadan Mehta, Isaac Karikari,Shahid Mehdi Nimjee, Allan H. Friedman,Carlos A. Bagley, Robert E. IsaacsIntroduction: Intradural extramedullary(IDEM) neoplasms can pose a challengefor spine surgeons. Determining thepreoperative pathology throughradiographic characteristics providesguidance for operative approach. Wereport the first systematic correlation ofaxial location and spinal cord level totumor pathology for IDEM.Methods:We performed a retrospectivereview of 98 consecutive patients rangingfrom 7 to 87 years old (mean age 49.9years) who presented with an intraduralextramedullary spine tumor in thecervical and/or thoracic regions andunderwent resection between February2000 and July 2009.Results: Across a combination of allIDEM tumors in the group, similar tumortype were seen at each spinal region(p=0.98). In addition, across all tumorsthe axial location was predominantlylateral in 70%, compared to 12.5%anterior and 17.7% posterior.Meningiomas were approximatelyequally distributed axially along 4quadrants with a roughly equaldistribution of arachnoid cap cells anddura. Schwannomas and neurofibromas

are lateral in position towards the nerveroots with 83.8% and 88.2% respectively.The pathology of anterior IDEM tumorsare predominantly meningiomas with72.7%, and the rest 27.3% wereschwannomas. From analyzing thepreoperative films on these anteriorschwannomas, it was noted the patientshad large growing tumors that startedlaterally and pushed the spinal cordposteriorly. Neurofibromas occured at ahigher frequency rostrally in the spinalcolumn. Schwannomas did notdifferentiate in incidence based on spinallevel.Conclusion: Preoperative radiographiclocation from our series of 98 patientssuggests a correlation between locationand pathology. Meningiomas aretraditional thought to occur mostly in aventral location, in our studymeningiomas occurred at a equalprevalence in all four quadrants of theaxial spine. Anterior tumors were morelikely meningiomas compared toschwannomas with a rate of 3:1. Alltumors that were anterior that were notmeningiomas had a lateral basedcomponent.

363Abnormal Inflammatory Response Metal-on-Metal (MOM) Disc ProsthesesPaul A. AndersonIntroduction: Severe inflammatoryresponses including large pseudotumorsto cobalt-chrome (CoCr) metal on metal(MOM) hip prostheses occur in 2-5% ofpatients resulting in manufacturer recalls,warnings by regulatory agencies andscientific organizations. Theinflammatory response appears to besecondary to wear debris and metal ionrelease. The purpose of this study is toreview six spinal arthroplasty cases withsevere inflammatory responses bringingto the attention of neurological surgeonsthis potential complication.Methods: Six cases have been reported allrequiring revision surgery for severeinflammatory reactions.Results: Two of these cases were cervicaland four lumbar. Five were in patients inclinical trials. All patients had new onsetof pain and four developed new onset ofclicking. All patients had severe pain andneurologic deficits, including myelopathyin two and cauda equina syndrome intwo. Two lumbar cases had DVT and onehad renal failure secondary to bilateralureteral obstruction. Time from surgeryto explantation ranged 9 -36 months.Pathology was similar to that seen inMOM hip arthroplasty. Histology revealed




avascular hyaline connective tissue withchronic inflammatory cells. In only onecase, third body wear debris was presentand one case had obvious severemetallosis, whereas all the others metalwear debris was not seen on standardlight microscopy.Conclusion:The six cases demonstratedthat similar pathologic processes to MOMhip arthroplasties will occur in spinalcobalt chrome bearing MOM devices.This problem has not been reported inthe stainless-steel device. The tumorswere not identifiable on radiographs orMRI and usually required CTmyelography. No (Co-Cr) MOMprostheses are approved, but over 1200have been placed in study patients.Neurosurgeons should be aware of thepossibility of severe inflammatoryreactions in any patient having pain orneurologic symptoms following a CoCrMOM arthroplasty.

364Low-Pressure Headaches in AdultPatients with Traumatic Brachial PlexusInjuryMarie-Noëlle Hébert-Blouin, Bahram Mokri, Alexander Y. Shin, Allen T. Bishop, Robert J. SpinnerIntroduction: Brachial plexus injury (BPI)presents with a combination of motorand sensory deficits, pain, but aregenerally not thought to be associatedwith headaches. However, it is well knownthat CSF leaks can occur in BPI patientsfrom nerve root avulsion and that CSFleaks may be associated with low-pressure headaches. In the literature, onlya few cases of headaches post BPI arereported. It is unknown if the prevalenceof headache in patients with BPI is low, orif they are unrecognized by physiciansand/or patients, the focus of care beingthe affected limb. The aim of this study isto determine the prevalence of low-pressure headache in patients with BPI.Methods: All patients presenting at ourbrachial plexus clinic with adulttraumatic BPI were asked to complete aquestionnaire on the presence andquality of headaches following theirinjury. The patients’ and injury’scharacteristics were subsequentlyreviewed.Results:During the study period(December 2008 to July 2010), 145patients filled the questionnaire. Of thesepatients, 22 reported new onsetheadaches occurring after their injury,seven of these patients having positionalheadaches. In patients with positionalheadaches, which are consistent with

low-pressure headaches, 6 had a clearpreganglionic BPI. Available imagingstudies revealed 2 patients withpseudomeningoceles, 1 patient with apseudomeningocele and evidence of CSFtracking in the soft tissue, and 2 patientswith CSF tracking into the pleural space.Conclusion: In this retrospective study,15% (22/145) of patients with traumaticBPI suffered from a new-onset headacheafter their injury, a third of these (7/22)having characteristics of low-pressureheadache. These headaches, likelysecondary to a CSF leak associated withthe BPI, occur in a significant proportionof patients and have been under-recognized.

365The Mechanical Influence of Top Loadingand Side Loading Screw Systems onConstruct AssemblyRobert M. Galler, Joseph Turner, Raphael P. Davis, John J. Labiak, Antonio ValdevitIntroduction:This study investigated thepressure and strains imparted uponspinal segments during surgicalimplantation of side loading (SL) and toploading (TL) pedicle screw systems.Methods: Porcine spines from T12-sacrum were instrumented withdisplacement transducers across thelateral aspect of the spinous processes ofL2- L3, L3-L4 and L4-L5 in both Anterior-Posterior Shear (APS) andTension-Compression (TC) directions.Spines were then instrumented witheither TL tulip screws or SL postedscrews. Prior to rod introduction,pressure film was placed on the anteriorspinal surface followed by completion ofan L2-L5 construct using pre-curved rods.Displacement transducer data wasconverted to strain. The Fuji film stripwas analyzed using Topaq software withparameters of mean pressure, contactarea and compressive force computed.Data between TL and SL screw constructswas compared using an unpairedStudent’s t-test.Results:Top loading systems displayed astatistically increased percentcompressive strain (relative to initialstrain) at L3-L4 in both the APS (P<0.05)and TC (P<0.006) directions. Othercomparisons for individual vertebraewere not statistically significant.Averaging over all levels displayed astatistically significant change in percentstrain between the TL and SL systems inboth the APS and TC directions (P<0.003).TL systems created a compressive strainduring set screw tightening; SL systems

created a tensile strain. Individualvertebral levels showed no significantpressure differences. However, whenaveraging over all levels, a significantmean pressure increase for SL systemscompared to TL systems (P<0.01) wasfound.Conclusion:Completing TL constructscreated more compressive strain,probably due to the rod reducing methodto bring the screw to the rod. Conversely,in SL constructs, the rod is brought to thescrew, producing more tensile strain.While some significant changes in strainsand pressures were measured, the overallconstruct assemblies were comparablefor both systems.

366Disparities Based on Race, Ethnicity andInsurance Status in the Access to andOutcomes after Surgery for CervicalSpondylotic Myelopathy in the UnitedStates, 2005-2008Hormuzdiyar H. Dasenbrock, Timothy F. Witham, Daniel M. Sciubba,Ziya L. Gokaslan, Ali BydonIntroduction:Differential outcomesbased on race, ethnicity and insurancestatus in the United States are well-documented. However, disparities in theaccess to and outcomes after surgery forcervical spondylotic myelopathy have notbeen previously evaluated.Methods:Data from the nationalinpatient sample (2005-2008) wereretrospectively extracted. Patients wereincluded if they had a diagnosis ofcervical spondylotic myelopathy orossification of the posterior longitudinalligament and underwent anterior orposterior cervical spine surgery(decompression with or without fusion).Multivariable logistic regression analyseswere conducted to calculate the odds ofdeath, non-routine hospital discharge,and treatment at a high-volume hospitalfor racial or ethnic minorities. Analyseswere also performed comparing patientswith a lack of or underinsurance (definedas Medicaid or self-pay) to those withprivate insurance or Medicare.Logarithmic multivariate regression wasused to evaluate the association of lengthof hospital stay and total hospital charges.All analyses were adjusted for differencesin patient age, gender, co-morbidities,admission type and hospitalcharacteristics.Results: A total of 22,600 admissions wereevaluated. The odds of in-hospitalmortality were not significantlyassociated with race, ethnicity orinsurance status. Length of hospital stay




was 5.0% and 6.7% longer for minorityand under- or uninsured patients,respectively (p<0.001); total charges were3.2% higher for minority patients(p=0.020). Non-Caucasian race orethnicity (OR: 1.23, 95% CI: 1.08, 1.40)and under- or lack of insurance (OR: 1.29,95% CI: 1.12, 1.49) were both associatedwith a significantly higher adjusted oddsof non-routine hospital discharge.Minority patients were significantly lesslikely to be treated at a high-volumehospital (OR: 0.51, 95% CI: 0.32, 0.82).Conclusion:Minority and under- oruninsured patients have longerhospitalizations and are less likely to havea routine discharge after surgery forcervical spondylotic myelopathy.Disparities also exist in access to high-volume centers for minority patients.

367Prospective Multicenter Evaluation ofPercutaneous Lumbar Pedicle ScrewPlacement Using the Oblique or “Owl’sEye” ViewCary Idler, Melvin Wahl, William R. TaylorIntroduction: Few studies have focusedon the oblique technique as a potentiallymore accurate method of placingpercutaneous lumbar pedicle screwswithout direct visualization. Aprospective, randomized, IRB-approvedstudy was undertaken to evaluate theaccuracy and safety of the obliquetechnique using computer assistance tofacilitate orienting the C-arm into theoblique view efficiently and accurately.Methods: After providing informedconsent, patients were randomized intoone of two groups: one underwentplacement of lumbar pedicle screwsusing the oblique technique with theassistance of Guidance; the other groupunderwent screw placement per thesurgeon’s usual technique usingfluoroscopy alone (non-Guidance).Fluoro time, screw placement time, andEMG thresholds were recordedintraoperatively for both groups. A neuralexam and VAS pain assessment wereobtained pre- and immediately post-op.A post-op CT scan was also obtained todetermine screw placement accuracy.Results: A total of 47 patients (27 femalesand 20 males) have been enrolled to-date.Primary surgeries included instrumentedALIF (9), XLIF (18), and/or TLIF (22). Ofthe 214 screws evaluated post-op by CT,11 (5.1%) breaches occurred: 8 (3.7%)medial, 2 (0.9%) lateral, and 1 (0.5%)inferior; 10 of the 11 pedicle breacheswere less than 2mm in magnitude, and 1breach in the non-Guidance group was 2-

4mm in magnitude. None of thebreached screws required revision, andthere were no significant differences inclinical improvements between patientswith breached screws (n=7) and thosewithout (n=40). Use of Guidance resultedin a statistically lower fluoro usage perscrew (p<0.001) and quicker placement ofguidewires (p<0.001). Although there wasno statistical difference in the averagetime it took to place each screw, averagetimes trended lower with the use ofGuidance (p=0.059).Conclusion:The oblique technique forpercutaneous pedicle screw placementusing NeuroVision Guidance providesfeedback on the appropriate targeting ofthe pedicle and successfully reduces theamount of fluoroscopy used withoutsignificantly adding to the time requiredfor placing pedicle screws.

368Clinical Correlation of Unilateral Motorand Sensory Deficits with MagneticResonance Diffusion Tensor Imaging andTractography in Patients with Spinal Cordand Root LesionsEve C. Tsai, Fahad A. Alkherayf, Arturo Cardenas-Blanco, Garth JohnsonIntroduction:Clinical correlation oftraditional magnetic resonance imaging(MRI) of the spinal cord with patientmotor and sensory deficits is limited.Diffusion tensor imaging (DTI) andtractography may improve clinicalcorrelation in patients with spinal lesionsas they are a more direct measure ofspinal cord fiber tracts. We evaluated theapplication of DTI and tractography inhealthy controls and patients with spinallesions to determine if this measurecorrelated with clinical status.Methods:Hospital ethics board approvalwas obtained for this study. Ten controlsand ten patients with spinal lesions thatunderwent routine MRI (October 2007 toApril 2010) with a tractography sequencewere obtained from the tractographyimaging and clinical database. Thetractography sequence was an axialdiffusion-weighted single-shot echoplanar imaging sequence using Grappaand 12 noncollinear gradient directions.MEDINRIA version 1.0.31 was used togenerate the fiber tracking images andfractional anisotropy (FA) and meandiffusivity (MD) were measured indelineated regions of interestcorresponding to the corticospinal tract(CST), propriospinal tract (PST) andspinothalamic tract (STT) of the spinalcord bilaterally using dedicated software.Results: In healthy controls, tract fibers

were continuous and FA measuredifferences between the right and left wasless than ¦0.106¦. Analysis could not beperformed at instrumented levels. Inpatients with unilateral sensory or motordeficits, fibers corresponding to thelesioned tract were absent on fibertracking images and there was asignificant decrease (ANOVA, p<0.001) inthe FA measurement of thecorresponding lesioned tract comparedto the intact tract on the contralateralside. These FA measurement differenceswere not seen if a unilateral deficit wasnot present or if there was no cord deficitand only a radicular deficit. MDmeasurements did not correlate withneurological deficits.Conclusion: Although further clinicalcorrelation with this technique isrequired, DTI with tractography mayimprove the MRI detection of unilateralCST, PST, or STT deficits in humans withspinal lesion and may discern cordlesions from radicular lesions. Futurework will evaluate whether the fibercontinuity changes and FA differencescorrelate with clinical status over time.

369Theoretical Increase of Thyroid Cancerfrom Cervical Spine MDCT in PediatricTrauma PatientsRyan D. Muchow, Paul A. Anderson, Kelly EganIntroduction:There has been a dramaticincrease in the number of computedtomography (CT) scans performed eachyear in the United States. Use of CTduring cervical spine clearance inpediatric trauma patients enhancesdiagnostic accuracy but delivers highdoses of radiation to the thyroid. Thepurpose of this study is to calculate thedose of radiation delivered to the thyroidfrom a cervical spine CT and calculatetheoretical thyroid cancer inductionrates.Methods: A retrospective evaluation of anIRB-approved pediatric trauma databasewas performed at an academic, Level Itrauma center. Data was collected bychart review to calculate the amount ofradiation absorbed by the thyroid fromplain radiographs and CT of the cervicalspine during clearance. Patients wereseparated into age groups 0-6, 7-11, 12-17, to facilitate age-dependentcalculations of theoretical thyroid cancerinduction.Results: Six-hundred seventeen patientsmet the inclusion criteria, 224 receivingplain radiographs and 393 undergoing CTof the cervical spine. The average amount




of radiation absorbed to the thyroid was0.90 mGy (males) and 0.96 mGy (females)from plain radiographs and 63.6 mGy(males) and 64.2 mGy (females). Averageexcess relative risk of plain radiographs is0.24% (males) and 0.51% (females) andfor CT is 13.0% (males) and 25.0%(females).Conclusion:CT cervical spine results in asignicantly higher dose of radiation to thethyroid than plain radiographs. Further,CT has a much greater potential toinduce thyroid cancer, particularly infemales and younger-aged patients.

370Does Arthroplasty Design Impact CervicalSpine Kinematics: An Analysis of theProDisc-C, Prestige LP and Synergy DiscNeil Duggal, Bruno C.R. Lazaro, Kemal Yucesoy, Kasim Zafer Yuksel, Izabela KowalczykIntroduction:Cervical total discreplacement (TDR) has emerged as asurgical option to preserve motion andpotentially avoid adjacent segmentdisease (ASD) after anterior cervicaldiscectomy and fusion (ACDF). Recently,much attention has been directed to theability of a given device to maintainand/or restore normal segmentallordosis. Post-arthroplasty kyphosis canresult in increased stresses transmitted tothe facet joints, potentially leading toASD.Methods: Sixty patients wereretrospectively analyzed and divided intothree groups, receiving either theProDisc-C, Prestige LP or Synergy disc.Only single-level arthroplasty cases wereincluded in this study. Lateral dynamicradiographs of the cervical spine wereanalyzed using QuantitativeMeasurement Analysis (QMA) software toanalyze the kinematics at the index levelpreoperatively and postoperatively.Several parameters were collectedincluding: range of motion (ROM); discangles (DA); shell angles (SA); anteriorand posterior disc heights (ADH/PDH)and center of rotation (COR). Pre andpostoperative data was compared usingStudent’s t-test with a p<0.05 level forsignificance.Results: Postoperatively, all three devicegroups maintained adequate ROM at theimplanted level. With respect to the SA,the Synergy disc demonstrated the leastvariability, maintaining 6° lordoticconfiguration between the deviceendplates. Both the Prestige LP andProDisc-C had an unpredictable impacton SA. All three discs significantlyincreased ADH and PDH (p<0.01). There

was an anterior shift in COR X with theProDisc-C and Synergy disc (p<0.05) anda superior shift of COR Y with the Prestigeand Synergy disc (p<0.05).Conclusion:The goal for motionpreservation at the implanted level wasachieved with all devices. Synergy discwas unique in its ability to alter the deviceangulation by 6° of lordosis.

371Implications of Number of Fused Levels inthe Outcome of Patients withDegenerative DiseasesAsdrubal Falavigna, Orlando Righesso,Alisson TelesIntroduction:The objective was toevaluate the clinical and functionaloutcome of patients with lumbardegenerative disease submitted to spinalfusion according with the number of thevertebral levels to be fused.Methods: A prospective comparativestudy in patients with degenerativediseases that were submitted to fusion ofone (G1), two (G2) or three or more (G3)levels with a 6-month follow-up. Thepatients were evaluated in thepreoperative, 30 days and in 6 monthspostoperatively with validatedinstruments (Numerial Rating Scale, NRS;Oswestry Disability Index, ODI;Hospitalar anxiety and depression scale,HADS). The analyses were conductedwith SPSS. Comparisons among thegroups were done with ANOVA en chi-square tests. The Post-Hoc analyses wereconducted with Bonferroni’s test.Results: 65 patients (G1 = 21; G2 = 25; G3= 19) were included in the study.Thegeneral characteristics of the groups, themean age was greater in G1 and lower inG3 (G1 = 45.4 ±13.1; G2 = 50.8 ± 11.8; G3 =55.9 ± 9.93; P = 0.024). There was nodifference among the groups in relationto the gender, previous surgery, evolutionof the symptoms and workcompensation. The duration of surgeryand bleeding were larger in G3 (P <0.05).The incidence of postoperativecomplications was higher in G3,comparing with G1 and G2 (P = 0.022). Nostatistically significant difference wasdetected concerning hospital stay andtransoperative complications among thegroups. The intensity of pain was higherin G3 in the postoperative evaluation of30 days, but that difference disappears in6 months postoperative. There was nodifferences in relation to disability (ODI)(G1 = 18.3 ± 13.0; G2 = 23.8 ± 13.6; G3 =27.81 ± 11.7; P = 0.206), depression andanxiety (HADS) (G1 = 8.71 ± 4.73; G2 =12.72 ± 8.77; G3 = 14.58 ± 7.84; P = 0.127)

and satisfaction among the groups (P =0.140).Conclusion:There was no difference inrelation with the pain, disability,depression and anxiety and postoperativesatisfaction among the groups. Thepatients with 3 or more fused levelspresented higher age and postoperativecomplication rates.

372Multilevel Anterior Cervical Discectomyand Fusion without SupplementalPosterior Instrumentation for CervicalSpondylotic MyelopathyEdwin Andrew Stevens, Robert A. Marsh,Thomas A. SweaseyIntroduction: Anterior cervicaldiscectomy and fusion (ACDF) is a widelyaccepted intervention for cervicalspondylotic myelopathy (CSM). Despitenumerous potential benefits, someconsider pathology at 3 or more levels arelative contraindication to an anterior-only surgical approach for multilevelcervical pathology. Potentialdisadvantages of multilevel ACDF areincreased risks of approach and fusion-related complications. The purpose ofthis study was to review complicationrates and neurological outcomes usingACDF alone at 3 or more levels in themanagement of multilevel CSM.Methods: A retrospective chart reviewwas performed on patients with CSMwho underwent ACDF at 3 or more levelswithout supplemental posterior fixation.Choice of instrumentation was consistentthrougout the series.(Fig.1) The variablesreviewed included perioperativecomplications, hospital length of stay,and hardware/fusion relatedcomplications. Pre- and postoperativeNurick scores were used to assessneurological outcomes.Results: A total of 82 patients underwenta 3-level (n=41), 4-level (n=39), or 5-level(n=2) ACDF without posteriorstabilization. Mean follow-up was 16months (range, 0-47). A significantimprovement in pre- and postoperativeNurick grades from 1.98 to 0.49 wasobserved (p=<0.0001). An overallcomplication rate of 40.2% was observed.The most common complications weredysphagia (19.5%), dysphonia (6%), non-union and/or hardware failure (7.3%).The postoperative symptoms ofdysphagia and dysphonia were transientin all except one case. Re-operation wasperformed in 3 patients for symptomaticpseudoarthrosis and/or hardware failure.Conclusion:The present review supportsthe safety and efficacy of anterior-only




ACDF at 3 or more levels in the surgicalmanagement of CSM. Favorable earlyneurological outcomes were suggested bysignificant improvement in Nurickmyelopathy grades. Approach andfusion-related complication rates usingthe described technique comparefavorably to previously published studiesof multilevel ACDF as well ascircumferential fusion procedures.

373Lateral Transthoracic Minimally InvasiveApproach for Central Thoracic DiscHerniation: Initial Experience in SevenCasesManish K. Kasliwal, Harel DeutschIntroduction:Various surgicalapproaches exist for management ofthoracic disc herniations. Though theposterolateral approaches have becomethe preferred approach for thoracic discherniation especially with the applicationof minimally invasive techniques in therecent years; it remains true that lateral oranterior approaches provides superiorexposure for removal of central discherniations as compared to posterolateralapproaches; though at the cost of addedmorbidity due to the surgery itself. Theauthors describe their initial experiencein treating central thoracic discherniations through a novel minimallyinvasive lateral approach.Methods: Seven patients with central discherniation were managed with minimallyinvasive lateral transthoracic approachfrom 2007 - 2010. Surgical techniqueconsisted of a lateral position followed bytransthoracic exposure through tubularretractor system without the need ofintraoperative lung collapse or postoperative chest tube placement. Clinicaldetails including age, sex, clinicalpresentation, surgical details,complications and outcome at lastfollow-up was analyzed.Results: Patients ranged in age from 30 to70 years (mean 52 years). The duration ofsymptoms ranged from 4 days to 3 years.Central thoracic disc herniations wereidentified at the following levels: T6-7(one patient), T7-8 (two patients), T8-9(two patients), T9-10 (two patients) andT10-11 (one patient). One patient hadtwo disc herniations. The average lengthof stay in the hospital was 2.6 days (range,1 to 4 d). Follow-up was available for allthe patients. All patients improved aftersurgery. Degree of preoperative deficit asassessed by Nurick’s grading wasimportant as patients with higherNurick’s grade (4-5) had little recovery atlast follow up as compared to those with

lower Nurick’s grade (0-3). No patientdeteriorated after surgery.Conclusion:Minimally invasive lateraltransthoracic approach surgery usingtubular retractor system for centralthoracic disc herniation is safe, effective,and provides a minimally invasivealternative without the morbidityassociated with traditional transthoracicapproaches.

374Radiographic Outcomes in Two-levelACDFs: Comparison of Smokers and Non-smokers at 1- Year Follow-upW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:Of our single-siteconsecutive series of 184 two-level ACDFpatients, 62 smoked at the time ofsurgery. Two-level ACDF results insmokers are presented to show the safetyand utility of the procedure in thispopulation.Methods: 184 patients underwentinstrumented 2-level cervical fusion.Patients were assigned to one of twotreatments arms that included acomposite of DBM plus autogenousendplate reamings, incorporated intoallograft bone dowels or PEEK spacers; allsurgeries were stabilized with dynamicanterior plating. Anteroposterior andlateral radiographs were obtained atthree, six, and twelve month intervals.Fusion was defined as, uninterruptedbridging of mineralized bone across theinterbody space without motion onflexion-extension radiographs.Results:Of 184 patients, 62 were smokers(22M, 40F; age 52.8 yrs) and 122nonsmokers (45M, 77F; age 57.5 yrs).Average 12-month Lenke score across allsubsets was 1.07 (smokers 1.08;nonsmokers 1.07). At 24 months, averageLenke score across all subsets was 1.03(smokers 1.00, non smokers 1.02). Therewere no infections, neurologiccomplications or plate breakages. Onepatient, a 59 year-old diabetic malesmoker, developed a pseudarthrosis; atthe 6-month follow-up, the patientremained asymptomatic and declined re-operation.Conclusion:The combination of ademineralized bone matrix-local bonecontained within allograft dowels orPEEK spacer resulted in similar fusionrates (> 97%) for both smokers andnonsmokers at 12 months and 24 monthspostoperatively.

375Graft Extrusion in AxiaLIF®W.B. Rodgers, William Douglas Smith, KyleMalone, Edward J. Gerber, Jody A. RodgersIntroduction:The AxiaLIF® L5-S1 fusionis performed while leaving the annulousand ligamentous structures intact. Whenthe annulous has been compromised,graft extrusion from the disc space ispossible.Methods: Review of a combination of 456AxiaLIFs® by 2 surgeons.Results: 5 patients (1.1%) experiencedgraft extrusion, 4 of which were revised.Case 1: A 64-year-old with a transitionalanatomy at L4-5 was scheduled toundergo an L4-5 XLIF® and L5-S1AxiaLIF®. When a lateral corridor forapproach could not be accessed, theXLIF® was aborted and the patientunderwent a two-level L4-S1 AxiaLIF®.Shortly after, the patient developed aninfection in the aborted XLIF® incisionsite. A CT showed the graft material hadextruded anteriorly from the L4-5 discspace (Figure 1). The patient wasasymptomatic and did not requirerevision. Case 2: A 30-year-old underwentan AxiaLIF®. The patient readmitted tothe hospital POD4 complaining of painand neurological deficits in the back andlegs. A CT revealed graft extrusionposteriorly into the intradural space, andan operation was performed to removethe dura (Figure 2). Case 3, 4, and 5: A 53-year-old female with DDD and instabilityat L5-S1, a 62-year-old female withseveral degenerative spine conditions,and a 37-year-old woman with a diskherniation at L5-S1, all underwent anAxiaLIFs. All 3 patients had prior annulartears, and all 3 patients experienced arecurrence of symptoms at 6 weekspostop AxiaLIF. MRIs revealed graftmaterial herniations through priorannular tears (Figure 3), and allunderwent laminotomy and removal ofgraft material. All 3 report residualsymptoms. One was revised at 12 monthsfor pseudarthrosis.Conclusion:Compromises in theannulous, could lead to graft extrusion, asthis system uses graft as a disc distractingagent, thus greatly increasing intra-annular pressure.




376Disparities Based on Race and Ethnicityin the Timing of Surgery for Acute SpinalCord Injury in the United States, 2005-2008Hormuzdiyar H. Dasenbrock, Timothy F. Witham, Daniel M. Sciubba,Ziya L. Gokaslan, Ali BydonIntroduction:While disparities in theAmerican healthcare system are well-established, the impact of race andethnicity on the outcomes after surgeryfor acute spinal cord injury has not beenexamined before. Moreover, although theearly intervention after acute spinal cordinjury is generally preferred, the effect ofrace and ethnicity on the timing ofsurgery has not been previouslyevaluated.Methods:Data from the nationalinpatient sample (2005-2008) wereretrospectively extracted. Patients wereincluded if they had a diagnosis of acutespinal cord injury, underwent spinaldecompression with or without fusionand were admitted emergently orurgently. Multivariable logistic regressionanalyses were conducted to calculate theodds of death, the performance ofsurgery on the day of or day afteradmission and treatment at a high-volume center for racial or ethnicminorities (defined as a race or ethnicityother than Caucasian). Logarithmicmultivariate regression was utilized todetermine the association of race orethnicity with length of hospital stay andtotal hospital charges. All analyses wereadjusted for differences in patient age,gender, co-morbidities, primaryinsurance payer and hospitalcharacteristics.Results: A total of 4,991 admissions wereevaluated. Adjusted odds of in-hospitalmortality were not significantly differentbetween Caucasian and minoritypatients. However, minority patients weresignificantly less likely to have surgeryperformed on the day of or day afteradmission (OR: 0.68, 95% CI: 0.54, 0.84).Non-Caucasian race or ethnicity wassignificantly associated with a lower oddsof treatment at a high-volume hospital(OR: 0.52, 95% CI: 0.31, 0.90). Length ofhospital stay was 2.6% longer for minoritypatients (p=0.028), but there was nosignificant difference in total hospitalcharges.Conclusion: Recent nationwide datashow that racial and ethnic minoritypatients with acute spinal cord injury areless likely to receive early interventionafter hospital admission when comparedto Caucasian patients.

377Dynamic EMG Testing for the Placementof Lumbar Pedicle ScrewsAntoine Tohmeh, Robert BazzanoIntroduction: Evoked EMG has beenshown to be a sensitive tool for assessingpedicle integrity after the placement ofpedicle screws. This post-hoc “Basic”testing allows for identification of breachintraoperatively and repositioning ofscrews if necessary, but with additionaltime, trauma, and limited correctionability. A prospective, IRB-approved studywas undertaken to evaluate theeffectiveness of “Dynamic” EMG testing,which enables active monitoring duringpedicle preparation and screw insertion,enabling changes in pedicle trajectory tobe made before a breach occurs.Methods: Lumbar pedicle screws wereplaced using Dynamic testing whereEMG feedback was provided to thesurgeon on a randomized basis amongscrews in each patient. EMG thresholdswere collected during cannulation,tapping, and placement of each screw.Final screw positioning was confirmedwith a Basic screw test after placement.Intraoperative redirections based onEMG feedback were documented. Aneural exam and VAS pain assessmentwere performed pre-op, post-op, and 4-6weeks after surgery. A post-op CT scanwas obtained and was evaluated for screwplacement accuracy by an independentspine surgeon.Results: A total of 44 levels were treatedwith instrumented XLIF and/or TLIF with137 screws placed. 8 (6%) breaches wereidentified by post-op CT: 6 (4%) medial, 1(1%) lateral, and 1 (1%) inferior. Allbreached the pedicle by less than 2mm,were without sequelae, and no revisionswere required. Low EMG thresholdsduring pilot hole formation led to asignificant number of redirections(p=0.014) with no correlation toincidence of breach. There was asignificant correlation betweenthresholds during tapping and screwplacement and incidence of breach(p<0.001), suggesting that once aredirection was made and thresholdvalues continued to be low, the surgeonwas less likely to redirect and more likelyto breach, or that pedicle wall integrityhad already been compromised andscrew path could not be changed onceprepared.Conclusion:Dynamic EMG testingprovides safe, real-time predictivefeedback during pilot hole formation andplacement of pedicle screws. Earlier

warning of low thresholds providesgreater opportunity for redirection.

378An Injectable Thiol-acrylate Poly(ethyleneglycol) Hydrogel for Sustained Release ofMethylprednisolone Sodium Succinate forTreatment of Spinal Cord Injury and inNeurosurgical ApplicationsChristopher D. Pritchard, Timothy M. O’Shea, Daniel J. Siegwart,Eliezer Calo, Daniel G. Anderson, Francis M. Reynolds, John A. Thomas,Jonathan R. Slotkin, Robert Langer, Eric John WoodardIntroduction: Systemic administration ofhigh-dose methylprednisolone (MP) hasbecome controversial as a clinicaltreatment option for spinal cord injury(SCI) due to its potential serious adverseside effects. Alternatively, the use of abiomaterial to locally deliver this steroidcould avoid increased risk of infection,delayed wound healing, pneumonia andsepsis while still providing an anti-inflammatory effect to the site of injury.We developed an injectable poly(ethyleneglycol) (PEG)-based hydrogel withcontrolled gelation that exhibits idealphysical properties for controlled releaseof MP.Methods:Gelation was monitored bydynamic rheology and Fourier transforminfrared spectroscopy (FT-IR).Mechanical properties were alsocharacterized using tensile specimentesting and analysis of sol/gel propertiesand equilibration behavior. Releasekinetics of methylprednisolone sodiumsuccinate (MPSS) from the hydrogel wasanalyzed using high performance liquidchromatography (HPLC).Results:Gelation from a liquid state wasachieved under physiological conditionsin 7.7 minutes. Mechanical testingrevealed properties similar to soft humantissues, with an elastic modulus of 189.8kPa. The hydrogel exhibited syneresisupon equilibration at 37 degrees Celsius,reducing from 25 wt.% to 39 wt.%polymer. The drug release profile wasfirst-order over a period of over 10 daysand independent of the initial drugconcentration.Conclusion:This rationally designedhydrogel is a potential candidate for localcontrolled release of MP in theintraparenchymal and peridural spaces ofthe spinal cord. Drug dosage for localadministration could be individuallytailored without affecting the release timeperiod or hydrogel volume. Syneresis mayensure that no pressure is exerted by thehydrogel upon equilibration to avoid




compression of neural elements, makingit a potentially useful candidate inneurosurgical applications.

379Gait Analysis in Idiopathic ScoliosisPatients in the Preoperative and Post-Operative PeriodGulden Demirci, Ulas Yener, Tuychiboy Abdullaev, Enis Saban, Yasar Bayri, Memet Ozek, Deniz KonyaIntroduction:The surgical correction andstabilization is inevitable for theprogressive scoliosis patients despite theconservative treatment while preservingmobility as much as possible and aproper gait and balance. In this study wepresent 22 idiopathic scoliosis patients’preoperative and postoperative gaitanalysis comparison results that wereoperated in our clinic.Methods:We had operated 22 idiopathicscoliosis patients during the periodbetween August 2009 and September2010 at our clinic. The patients were 13girls and 9 boys who ranged in age from10 to 17 years (median age, 13.7). We hadperformed 7 to 14 levels of posteriorinstrumentation. The radiologicalevaluation was performed before, earlypostoperative, and 6 months after thesurgery. In addition to that gait analysiswas performed before and 6 months afterthe surgery.Results: According to gait analysis thefirst sign of reversal of the center ofgravity to normal was seen at the distalmuscle groups. Physical treatment’scontribution to reversal process wasenormous. Recovery of hyperflexion ofthe pelvis, hip and knee in the mid-stancephase was seen. Hyperactivity of thegastocnemius and soleus muscles in theplantar/dorsal flexion of the ankle wasreversed to normal limits as first signs ofnormalization of gait in these patients.Conclusion:Gait analysis is an importantand objective tool in evaluating thebalance and posture of scoliosis patientsin pre and postoperative period in clinicalpractice and directs the physical therapyafter the surgery.

380Anterior Cervical Foraminotomy withPreservation of the Uncovertebral Jointfor Unilateral RadiculopathyIzumi Koyanagi, Takahisa Kaneko,Tomohiro MurakamiIntroduction: Anterior cervicalforaminotomy has been developed as theminimally invasive surgery for unilateralcervical radiculopathy. The reportedsurgical procedures included

microsurgical removal of theuncovertebral joint. However, reoperationor recurrence of disc hernia after anteriorforaminotomy was also reported. Since2000, we have performed anteriorcervical foraminotomy with preservationof the uncovertebral joint. In thisprocedure, microsurgical drilling ismainly applied to the inferior border ofthe upper vertebral body. The uncinateprocess was only partially drilled at thebase to expose the affected root sleeve. Inthis study, we reviewed surgical results ofour patients and examined the usefulnessof this method.Methods:Twenty-five patients (dischernia 20, spondylosis 5) underwentanterior cervical foraminotomy forunilateral radiculopathy between 2000and 2009. There were 17 men and 8women, aged from 39 to 76 years (mean48.9 years). Foraminotomy at the singlelevel was performed in 19 patients, while6 patients underwent 2-leveldecompression.Results:Twenty-three patients (92%)showed good improvement of theirradiculopathy. Two patients with cervicalspondylosis underwent additionalanterior fusion 2 weeks and 5 monthsafter foraminotomy due to the remainedsymptoms. Postoperative follow-upradiographs of the cervical spine showedsignificantly decreased disc height aftersurgery. However, no patientsdemonstrated instability of the cervicalspine.Conclusion: Anterior cervicalforaminotomy with preservation of theuncovertebral joint can be an excellentmethod of surgical treatment of unilateralradiculopathy. This method is bestindicated to disc hernia in theintervertebral foramen. However, surgicalindication may be limited in spondyloticradiculopathy.

381Safety and Efficacy of OccipitocervicalFixation in Rheumatoid Arthritis PatientsDonald Y. Ye, Ajit A. Krishnaney, Edward C. BenzelIntroduction: A perceived high risk ofcomplications and surgical failure existsfor occipitocervical surgery inrheumatoid arthritis patients. This studyevaluates the efficacy and safety ofoccipitocervical fixation and arthrodesisin this population.Methods: A retrospective chart review of15 patients with a diagnosis ofseropositive or seronegative rheumatoidarthritis following occipitocervicalfixation at the Cleveland Clinic Center for

Spine Health between January 1, 2001and December 31, 2009 was conducted.The primary outcomes were changes inneurological function and pain at lastfollow-up. Secondary outcomes wererecorded for complications of surgeryand postoperative surgical failures.Results: Fifteen patients (mean age =64.6, female = 12) were evaluated for amean follow-up of 26.6 months.Atlantoaxial instability was the mostcommon indication (93.3%). Patients self-reported pain reduction in 80% of cases.Neurological improvement occurred in40%, while no patients deteriorated aftersurgery. Postoperative deaths werereported in two cases with one due tocomplications of surgery. No implantfailures were observed and bony fusionwas acquired in 93.3% of patients. Re-operation was only required for adjacentlevel degeneration (13.3%) and forpseudoarthrosis (6.7%). Othercomplications included surgical siteinfection (13.3%), dural tear (6.7%), anddysphagia (20%).Conclusion: A consistent improvement inpain and neurological function in allpatients after surgery, especially given thelow incidence of complications, wasobserved. However, need for consistentand long-term follow-up of these patientsis recommended due to increased strainon the subaxial spine that may potentiatedegenerative processes and lead to re-operation.

382Minimal Access Spine Surgery forMetastatic Spinal Tumours Followed byStereotactic Body Radiotherapy:Technique and Preliminary OutcomesEric M. Massicotte, Matthew Foote, Rajesh Reddy, Arjun SahgalIntroduction:To report a novel approachin the treatment of spinal metastases withepidural disease causing mechanicalinstability using a combined minimalaccess spine surgery (MASS) techniquefor tumor decompression andreconstruction, followed by stereotacticbody radiotherapy (SBRT).Methods: A retrospective review of thefirst ten consecutive patients treated withMASS followed by SBRT was conducted.The MASS technique is based on atubular retraction system to gain accessfor decompression and mechanicalstabilization achieved usingmethylmethacrylate (MMA). SBRTconsisted of one to five high dose perfraction treatments. Eight patients weresymptomatic at baseline, and pain,disability and quality of life prospectively




determined using the visual analoguescore, Oswestry disability index andshort-form-36 version 2, respectively.Results:The median follow-up was 13months (range, 3-18). MASS successfullydecompressed each patient, and themedian blood loss was 335 ml. Themedian time to SBRT treatment planningwas 6.5 days. Local control was observedin 7 of the 10 patients. Improvement inpain, disability and quality of life wasobserved post-SBRT. One patient had acomplication of a dural tear duringMASS. One patient required a furthersurgical procedure to decompressionrecurrent local disease. One patient whodid not go on to be treated with SBRT, andconsidered separately in this analysis,suffered acutely from MMA extravasationrendering the patient myelopathic andsubsequently died.Conclusion: Safety and preliminaryefficacy is reported with our MASS andSBRT combined approach for patientswith spinal metastases and epiduraldisease, however, local control benefitsrequire confirmation upon long-termfollow-up.

383Our Experience with PercutaneousBilateral Facet Motion AugmentationSystem: A Report of 60 CasesAnthony P. Fabrizi, Raffaella Maina, Luigi SchiabelloIntroduction:Minimally invasive surgicaltechniques have been rapidly diffusing inrecent years. Different devices are nowavailable for the treatment of lumbarspine degenerative disease. They allow agood symptoms relief as well as a shorttime of surgery and hospitalization. Wepresent our experience with a novelsystem for percutaneous bilateral facetmotion augmentation. This system wasdesigned to limit painful spinal motion,enlarge the foramina and achieveintradiscal decompression. It iscomposed of a bilateral titanium anchorconnected to a silicone stabilizer.Methods: Since February 2009 we usedthe percutaneous facet motionaugmentation system at our institution.Major indications were single leveldegenerative disc disease and spinalstenosis. We consider 60 patients for thepresent study. Mean age was 46.6 yearsold (range 38-72). Treated levels were L4-L5 (28 cases), L3-L4 (12 cases), L5-S1 (12cases) and L2-L3 (8 cases). We performedthe surgical approach under spinalanesthesia whenever was applicable (53%of patients). Follow-up data wererecorded at 2-months and 6-months.

Clinical results were assessed using theVisual Analogic Scale (VAS) and the EQ-5D questionnaire.Results:Overall results were satisfactoryin 56 patients. Mean pain VAS scoreimproved from 7.7 at baseline to a valueof 2.2 at 2-months follow-up. Theremnant 4 patients had minimal or nochanges. Two of these patients weresubsequently treated with traditionaltranspedicular stabilization system. Meanprocedure time was 26 minutes (range18-40 minutes). Early mobilization waspossible 12 hours after surgery in allpatients. Hospital discharge was possibleat 24-36 hours. No intra- andpostoperative complications wereobserved.Conclusion: Preliminary results are goodand promising. Surgical technique is easyand satisfy requisites for a minimallyinvasive procedure. Percutaneousbilateral facet motion augmentationsystem represents a modern option tospinal fusion in selected cases.

384The Frankel Scale Is More Effective thanRevised Acute Physiology and ChronicHealth Evaluation System (APACHE II) forPrediction of Mortality in Cervical SpinalCord InjuryAli Dalgic, Denizhan Divanlioglu, Murat Korkmaz, Onder Okay, Ergun Daglioglu, Ozhan Uckun, Osman Nacar, Ali Yildirim, Deniz BelenIntroduction:The revised AcutePhysiology and Chronic HealthEvaluation system (APACHE II) is aphysiologically based system including 12physiological parameters. Cervical spinalcord injury (CSCI) can be a devastatingevent causing not only motor andsensory impairments but also autonomicdysfunction. Functional and morphologicchanges in the sympathetic nervoussystem can affect respiratory,cardiovascular, renal and gastrointestinalsystems. Purpose of the study is toinvestigate for predictive value ofAPACHE II according to the mortality,and to compare with Frankel scale.Methods:This retrospective studyincluded 47 patients with CSCI between2005 and 2009. Patients were admittedfrom the emergency unit and treated atleast 24 hours after their admission.APACHE II and Frankel scores weremeasured from the charts and collecteddata was analyzed for sensitivity,specificity and prediction of mortality bySPSS for Windows.Results:The study included 36 males and11 females. The ages of the patients

varied between 21 and 82 years (meanly45.7). Ten cases were scored with FrankelA, 2 cases B, 3 cases C, 14 cases D and 18cases E respectively. Nine patients weredead and 38 cases were discharged aftertreatment. Prediction of mortality withFrankel scale is significantly helpful thanAPACHE II (table 1).Conclusion:Disrupting autonomicsystem causes respiratory, cardiovascular,renal and gastrointestinal complicationsthat have been considered to be the mostfrequent adverse events after SCI.Recently; hyponatremia and hematologicabnormalities have been recognized asthe leading cause of poor outcomefollowing SCI. Well-recognizedconsequence of CSCI caused tomultisystemic dysfunction, however,Frankel scoring is available and superiorto APACHE II still. This study is limitedwith fewer cases and included the first(only one) measurement of APACHE II.Further studies should include the follow-up values in hospitalization time andthen compare with other scales forassessment of outcome and mortality.

385Clinical Study on Accuracy Measurementof Neuronavigated O-Arm Image-guidedSurgery of the Thoracic SpineDuccio Boscherini, Raymond Yerly,Maurizio Pintucci, Marco BarberoIntroduction: Image-guided navigationhas reportedly increased the accuracyand safety of pedicle screw insertion anddecreased complication rates. In formerstudies, the result of image-guidednavigation was mainly comparedqualitatively with the result ofconventional fluoroscopy-guidedprocedures. The present clinical studyaims at measuring in a clinical setting theaccuracy of O-Arm (three-dimensionalimaging device) coupled to aneuronavigation system. This is done bydigitally overlapping the image of thevirtual position of a needle tip displayedon a navigation system afterpercutaneous introduction into athoracic vertebral body during avertebroplasty procedure with the realposition of the needle tip when using O-Arm intraoperative acquisition.Methods: Forty-eight Yamshidi navigableneedles were placed through a unilteralextrapedicular approach into fracturedthe vertebral bodies of thoracic T10-L2levels using O-Arm guided navigation.The navigated needle tip positions werecompared with the real needle tippositions from 3D O-Arm volumesacquired after immediate completion of




the needle procedure. Dynamic referenceframe was attached to the iliac crest. Bothdigital images acquired during theprocedure are overlapped and deviationis measured.Results:The mean difference betweenthe navigated needle position and theactual needle position was 0.8 ± 0.3 mm.Conclusion: Accuracy of O-Arm guidednavigation is high even in a clinicallyrelevant setting and is superior to theaccuracy reported in other studies

386Mini-Open Transpedicular Corpectomieswith Expandable Cage ReconstructionDaniel C. Lu, Dean ChouIntroduction:Transpedicularcorpectomies are frequently used toperform anterior surgery from a posteriorapproach. Minimally invasivethoracolumbar corpectomies have beenpreviously described, but these areperformed through a unilateral approach.Bilateral access must be obtained for acircumferential decompression whenusing such techniques. We describe atechnique which allows for a minimallyinvasive mini-open transpedicularcorpectomy, 360 decompression, andexpandable cage reconstruction througha single posterior approach. This isperformed with percutaneous pediclescrews, the trap door rib head osteotomy,and a single midline fascial exposure.Methods: In the one-year period between2008 to 2009, the authors performed 8mini-open transpedicular corpectomyprocedures by minimally invasiveapproach in the thoracolumbar spine (T3to L1) on patients with age ranging from20 to 81 years for various pathologiesinvolving trauma, infection, andmetastatic disease. A comparison opencohort was obtained by matching thepathological diagnosis to the mini-opencohort.Results:The mean blood loss was 1800cc. Four of the patients underwentallograft fusion while the other 4underwent autograft fusion. One patientdeveloped a postoperative woundinfection. Another patient required areoperation for instrumentation failure.All patients with preoperative deficitsdemonstrated improvement of motorscore after the procedure. A cohortcomparison with the open and mini-open group was performed. We did notfind a statistically significant difference inthe parameters of age, EBL, operativetime, complication rate, and follow-uplength. There was however, a trendtowards significance in EBL of mini-open

(1213 cc) vs. open cases (2450 cc; p =0.086).Conclusion:The minimally invasivetranspedicular corpectomy andexpandable cage reconstruction can beperformed with a combination ofpercutaneous pedicle screws, a directmidline approach, and a trap door ribhead osteotomy.

387Minimal Access Surgery via the UnilateralMuscle Splitting Approach: An InnovativeBreakthrough in Intraspinal TumorSurgeryIbet Marie SihIntroduction: Surgical treatment optionsof intraspinal tumors, which commonlyinclude nerve sheath tumors,meningiomas and astrocytomas, ofteninclude open laminectomy, multilevellaminectomies, or hemilaminectomies(with the option of intradural dissection).However, consequences of surgeryinclude muscular, ligamentous and bonystructure disruption leading to spinalinstability, pain syndromes, and possiblelengthy hospital stay and treatment.Minimal access spine surgery employingtubular dilators to split muscles providesgood direct visualization of the operativefield with minimal tissue trauma.Although its use is mainly in degenerativespine conditions, its applicability inintraspinal tumor surgery is not yet fullydefined.Methods: A prospective cohort ofconsecutive patients operated on by theauthors (first 15 to minimal access group,next 15 to conventional group) was done.Demographic data and Nurick, ASIAmotor, VAS pain scores at pre-op, day1post-op, 1 month post-op and 3 monthspost-op were obtained using databases.Results:The mean ages were 38.1 and36.5 years respectively. At preop, day 1post-op, 1 month post-op and 3 monthspost-op, the mean Nurick and ASIAscores were comparable in both groups.The mean VAS pain score of the minimalaccess group was less by at least 1-2points compared to the conventionalgroup. Although the mean tumor sizeswere similar, the incision length wasalmost half in the minimal access group.In contrast to the conventional group, theoperative time was shorter by 18%, themean blood loss was considerably less by59% and the discharge time was less by28% in the minimal access group.Conclusion:Minimal access surgery ofintraspinal tumors via the unilateralmuscle splitting approach using theQuadrant system is indeed an innovative

alternative to laminectomies and bilateralparaspinal muscle dissection surgeries.However, it is recommended that a largerstudy population, randomization, longerfollow-up periods will be done to furthersubstantiate the applicability of thistechnique to intraspinal tumors.

388Performance Status After LumbarArthroplasty in the MilitaryLuis M. Tumialan, Ryan Ponton, Wayne GlufIntroduction: Information regarding thelevel of physical performance attainedand restrictions or limitations is lackingfrom the several FDA trials onarthroplasty. This data is essential for themilitary surgeon, tasked with guiding thepostoperative management of anarthroplasty patient and return them tofull duty.Methods:The surgical database at asingle, tertiary care military treatmentfacility was queried for all active dutypatients who underwent placement oflumbar arthroplasty device from April2007 until April 2010. Specific inquirieswere made as to the level of performanceattained, i.e. parachute jumping, diving,running and deployment. Each cohortwas then compared to an age and levelmatched anterior lumbar interbodyfusion.Results: Fourteen patients were identifiedthat underwent lumbar arthroplastyduring the above mentioned time period.There were 12 men and 2 women with anaverage age of 37.3 years. The levelsoperated: L5-S1 (n=8), L4-5 (n=6). Twelveout of 14 (86%) patients in the lumbararthroplasty group returned tounrestricted full duty, after an average of22.6 weeks (range 12-29 weeks). Thiscohort was then age matched and levelmatched to 14 patients who hadundergone a single level ALIF. Sixty-sevenpercent of these patients returned tounrestricted full duty after an average of32.4 weeks. Although there was anapparent difference between the meantime to return to active duty, thisdifference was not statistically significant(p=0.156).Conclusion:The preliminary experiencewith lumbar arthroplasty in the militaryindicates that this technology iscomparable to arthrodesis and mayactually expedite return to active duty.Patients are capable of returning to a highlevel of rigorous training and physicalperformance. There are no apparentrestrictions or limitations required 6months after arthroplasty. A prospective




study of lumbar arthroplasty in themilitary is underway.

389Lumbar Microdiscectomy Outcomes inPatients Ages Twenty-One and UnderRandall W. Porter, Mark P. Garrett, Jodie B. WoznicaIntroduction: Surgical treatment oflumbar disc herniation in teenagers andyoung adults is uncommon, and thesepatients represent a unique demographicgroup. The long term outcomes of thispopulation is not well documented in theliterature..Methods:We reviewed the charts ofpatients ages twenty-one and under fromMay 2004 to September 2008. We queriedthe charts for initial surgical treatment,initial and long term surgical results andthe presence or absence of subsequentsurgery or the need for further painmanagement.Results:Twenty-eight patients ages 17-21(mean and median age of 20 years old)underwent lumbar microdiscectomy atour institution during the study periodafter failing to respond to conservativetreatment. Average follow-up was fiveyears with a median follow-up of fouryears. Two patients, upon preliminarychart review, required subsequentsurgical treatment. One patientunderwent decompression for recurrentdisc herniation at the same level 4months postoperatively. The secondpatient required decompression forstenosis at two adjacent levels that hadshown mild disease at the time of theinitial procedure. In addition, sevenpatients sought pain management forrecurrent disc herniation at a mean of 3.5years (median 4.0 years) postoperatively.Conclusion:Young adults and teenagersare an uncommon population requiringlumbar microdiscectomy. Thisretrospective review provides usefulinformation in counseling patientsregarding possible need for future surgeryor life style modification.

390Disparities Based on Race, Ethnicity andInsurance Status in the Access to andOutcomes after Surgery for LumbarSpinal Stenosis in the United States,2005-2008Hormuzdiyar H. Dasenbrock, Timothy F. Witham, Daniel M. Sciubba,Ziya L. Gokaslan, Ali BydonIntroduction:Disparities in the Americanhealthcare system are well-known.However, the impact of race, ethnicityand insurance status on the access to and

outcomes after surgery for lumbar spinalstenosis with or without spondylolisthesishas not been previously examined.Methods:Data from the nationalinpatient sample (2005-2008) wereretrospectively extracted. Patients wereincluded if they had a diagnosis of spinalstenosis or spondylolisthesis andunderwent lumbar decompression withor without fusion. Multivariable logisticregression analyses were conducted tocalculate the odds of death, non-routinehospital discharge, and treatment at ahigh-volume hospital for racial or ethnicminorities. Analyses were also performedcomparing patients with a lack of orunderinsurance (defined as Medicaid orself-pay) to those with private insuranceor Medicare. Logarithmic multivariateregression was used to evaluate theassociation of length of hospital stay andtotal hospital charges. All analyses wereadjusted for differences in patient age,gender, co-morbidities, and hospitalcharacteristics.Results: A total of 106,751 admissionswere evaluated. The adjusted odds of in-hospital mortality were not significantlyassociated with race, ethnicity orinsurance status. Length of hospital staywas 3.9% longer for under- or uninsuredpatients (p<0.001); total hospital chargeswere 0.6% and 2.0% higher for minorityand under- or uninsured patients,respectively (p=0.009). Non-Caucasianrace or ethnicity (OR: 1.03, 95% CI: 1.00,1.05, p=0.017) and under- or lack ofinsurance (OR: 1.20, 95% CI: 1.09, 1.33)were both associated with a significantlyhigher adjusted odds of non-routinehospital discharge. Both minority (OR:0.78, 95% CI: 0.73, 0.82) and under- oruninsured patients (OR: 0.69, 95% CI:0.59, 0.81) were significantly less likely tobe treated at a very high-volume hospital.Conclusion:Nationwide disparities existin the access to very high-volume spinesurgery; minority and under- oruninsured patients also incur higherhospital charges after surgery for lumbarspinal stenosis.

391Computed Tomographic MorphometricAnalysis of the Human Occipital Condylefor Occipital Condyle-Cervical FusionTien V. Le, Shannon Hann, Ali A. Baaj,Juan S. UribeIntroduction:Occipital condyle screwsserve as an alternative fixation point inoccipital-cervical fusion. Their placementrequires a thorough understanding of theanatomy of the occipital condyles andassociated structures. This is a computed

tomography (CT)-based morphometricanalysis of occipital condyles as it relatesto occipital condyle-cervical fusion.Methods:There were a total of 170patients examined with CT’s of theircranium and cervical spine at a singleinstitution for a total of 340 occipitalcondyles from March 6, 2006 until July 30,2006. All CT’s were negative for traumatic,degenerative, and neoplastic pathology.The anteroposterior length, thetransverse width, condyle height, screwangle, and projected screw lengths weremeasured in all condyles. Linearmeasurements were done on an EBWPortal 2.5 CT Viewer Workstation. Thelongest axis in the anteroposteriororientation of the occipital condyle wasaccepted as the length. The transversewidth was a line perpendicular to themidpoint of the long axis. The height wasmeasured in the coronal projection withthe thickest cranio-caudal portion of thecondyle. The screw trajectory starts 5mmlateral to the medial edge of the condyleand a line is directed anteromedially inthe longest axis. The angle is measuredrelative to the sagittal midline. The screwlength is measured from the outer cortexof the posterior wall to the outer cortex ofthe anterior wall.Results:The average and standarddeviations of occipital condylemeasurements were as follows:anteroposterior length was 22.38 mm ±2.19 (range 14.7 - 27.6), width was 11.18mm ± 1.44 (range 7.4 - 19.0), height was9.92 mm ± 1.30 (range 5.1 - 14.3), screwangle was 20.30° ± 4.89 (range 8.0° - 34.0°),and screw length was 20.30 mm ± 2.24(range 13.0 - 27.6).Conclusion:These measurementscorrelate with previous cadaveric andradiographic studies of the occipitalcondyle and emphasize the role ofpreoperative planning for feasibility ofplacement of an occipital condyle screw.

392Clinical Trial Design for Phase I/IIAEmbryonic Stem Cell Derived MotorNeuron Progenitor Transplant(MOTORGRAFT™) for Treatment ofInfantile Spinal Muscular Atrophy Type ISamer Ghostine, Rania, Chris Airriess,Shoshanna S. Vaynman, J. Patrick Johnson, Alexa Lynne Reeves, Hans S. KeirsteadIntroduction: Spinal muscular atrophy(SMA) Type I is a devastating, terminalpediatric genetic disorder characterizedby progressive degeneration of spinalcord motor neurons and concomitantdeterioration of muscles that control




crawling, walking, swallowing andbreathing. Motor skills start to regressbefore age six months leading to death byage 2 years.Methods: Stem cell transplantationtherapy presents a potential therapeuticapproach for motor neuron diseases suchas SMA. Our own pre-clinical studies haveshown safety and functional benefit of theembryonic stem-cell derived motorneuron, MotorGraft™ in multiple animalmodels. There are many challenges indesigning a clinical trial for a noveltherapy in a terminal pediatric populationsuch as validated efficacy outcomes,survival time, selection of appropriatecontrols, inclusion and exclusion criteria,appropriate surgical approach, cohortdesign and autopsy data.Results:Multiple focus groups were heldwith experts in the fields of pediatrics,neurology, transplant surgery,neurosurgery and motor neuron diseaseresearch to adress these challenges, andresulted in a fully developed clinicalprogram and trial design. Key safetyoutcomes include evaluation measuresfor tumor formation and migration ofcells. Exploratory efficacy outcomesinclude time to 16 hours of assistedventilation, and frequency of respiratoryinfections requiring hospitalization.Conclusion:The primary objective of thisclinical trial is to evaluate the safety andtolerability of MotorGraft™transplantation into the ventral horn ofthe spinal cord at multiple sites along thecranio-caudal axis in symptomatic SMAType I infants. The secondary objective isto evaluate the ability of MotorGraft™ toimprove function of damaged motorneurons.

393Sacroiliac Arthrodesis by MinimalIncision: Distraction Interposition Method,Short-term OutcomesChris Idemmili, John G. StarkIntroduction:The sacroiliac joint (SIJ) is amajor point of force transmissionbetween the spine and the pelvis. Thoughfusion has been advocated for SIJ painand disease, no procedure has receivedgeneral acceptance. The purpose of thisstudy is to report technical outcomes,and short-term functional outcomes ofpatients following sacroiliac arthrodesissurgery using a distraction-interferencetechnique.Methods: Fifteen patients, severelysymptomatic with SIJ pain, underwent SIJarthrodesis, using a combined extra- andpartial intraarticular technique featuringa posterior-midline 4cm incision,

controlled distraction/measurement ofthe extraarticular recess, BMP-2/allografting of adjacent surfaces, andapplication of a interference-fit, threadedimplant. Patient sample consisted of 4males and 11 females. Mean age was 43(range 22-65). Interim follow-up periodwas three months. The OswestryDisability Index (ODI) and Million VisualAnalog Scale (MVAS) were the primaryfunctional outcome measures. Patientreport of back and leg pain resolution wasalso recorded. Two types of globalassessment, improvement andsatisfaction, were collected. PreoperativeODI and MVAS scores were compared topostoperative scores using a paired t-test.A significance level of .05 was used.Results: Blood loss averaged 55cc (range10-300cc). Mean hospital stay was 2.2days. Average patient function improvedsignificantly. MVAS scores improved 35(±25) points (40%, p<.0001). ODI scoresimproved 10(±21) points (17%, p<.0001).Patients reported 75% resolution of backpain (95% Confidence interval: 66%-84%)and 91% resolution of leg pain(95%Confidence interval: 83%-98%).Conclusion: Judged by back and leg painrelief, the surgery is promising in allpatients. The SIJ region can be graftedand implanted by minimal incisionmethods. Patient satisfaction is high.There were no nerve injuries,displacements, infections, ormalpositioned implants. Most patientsshowed dramatic improvement by threemonths. Patients report a high percent ofback and leg pain relief. Significantimprovement in function is reflected inMVAS and Oswestry scores.

394Minimally Invasive vs. OpenTransforaminal Lumbar Interbody Fusion(TLIF): An Evidenced-based Review of theLiteratureOwoicho Adogwa, Scott Parker, Oran Aaronson, Joseph S. Cheng, Matthew J. McGirtIntroduction: It remains unknownwhether minimally-invasive vs. opentechniques for transforaminal lumbarinterbody fusion (TLIF) provides a betteroutcome for the treatment of lumbardegenerative disc disease andspondylothesis. We performed asystematic evidence-based review of theliterature to determine level of evidencethat supports the performance of aminimally-invasive vs. open techniquefor TLIF.Methods: Systematic Medline search wasperformed to identify all published

studies relating to outcome afterminimally-invasive or open TLIF. Levelsof evidence (I - V) were assessed for eachstudy and grades of recommendationwere generated (Good, Fair, Poor,Insufficient evidence) based on the NASSClinical Guidelines’ Levels of Evidenceand Grades of Recommendation.Results:There are no level I, one level II,and three level III studies comparingMIS- to open-TLIF. There are 15 level IVseries of MIS-TLIF and 21 level IV seriesof open-TLIF. There is fair evidence thatMIS- vs. open-TLIF is associated withdecreased blood loss and reduced lengthof hospital stay, but similar improvementin both short-term (6mo-2yr) and long-term (>2yr) pain and disability. There isinsufficient evidence to determine if MIS-vs. open-TLIF reduces operative time.Lastly, there is fair evidence suggestingthat MIS-TLIF is associated with similarfusion rates compared to open-TLIF.Conclusion:There are no level I studiessuggesting superior outcomes for MIS vs.open-TLIF for the treatment ofspondylolithesis or lumbar degenerativedisc disease. Systemic review of theliterature suggests that MIS-TLIF may beassociated with reduced blood loss andlength of hospital stay while providingequivalent short and long-termoutcomes.

395Comparing Vertebral Body ReconstructionImplants for the Treatment of Thoracicand Lumbar Metastatic Spinal TumorsSharad Rajpal, Roy Hwang, Thomas Mroz,Michael P. SteinmetzIntroduction: Surgery in metastatic spinedisease often requires vertebral bodyreconstruction following tumor resectionto provide anterior spinal columnsupport. No study to date has comparedspine interbody reconstruction devices inmetastic tumor patients. The goal of thisstudy is to compare the longevity ofstructural bone grafts, cages, andpolymethylmethacrylate (PMMA) asinterbody reconstruction implants inpatients undergoing corpectomy formetastatic tumors in the thoracic orlumbar spine.Methods: 37 patients underwentcorpectomy with subsequent interbodyreconstruction over a 15-year period at asingle institution. Surgical approach,hardware and interbody device type wasat the discretion of the attending surgeon.Longevity of interbody device wasprimarily evaluated in this study asdefined by the need for any revisionsurgeries or postoperative complications.




Results: 27 patients underwentreconstruction with metal implants and 5patients each had reconstruction withbone and PMMA (Table 1). 23 patientsand 14 patients had tumors in thethoracic and lumbar spine, respectively.Most common tumor diagnosis was lungcarcinoma. Three patients (8.1%)required additional surgery: one woundinfection, one hardware revision, and onefor resection of an intradural,intramedullary tumor not identified atthe time of the first operation (Table 2).Overall complication rate was 43.2% in 16patients. Postoperative complicationrates were 52%, 20%, and 20% in metal,bone, and PMMA implants, respectively.Rate of revision surgery was 40%, 3.7%and 0% in the bone, metal, and PMMAinterbody groups. Two patients diedwithin 30 days of their index spinesurgery, one from sepsis and one fromrespiratory failure.Conclusion:Vertebral bodyreconstruction following corpectomy formetastatic tumors to the thoracic andlumbar spine can be done effectively withmetal, bone, or PMMA. Metal implantsappear to have a higher rate of overallcomplications, with bone interbodyconstructs demonstrating higher level ofrevision surgery.

396Extreme Lateral Interbody Fusion (XLIF)in SmokersW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:The pre- and postoperativeresults of XLIF were collected to assessfeasibility and clinical and radiographicsuccess in smokers.Methods: In our single-site prospectiveseries of 932 XLIF patients, 308 smoked atthe time of surgery. Patient demographicsand clinical/radiographic outcomes wereassessed.Results: Patients ranged in age from 22-84 years (average 56 years) and weretreated for a variety of indications. 44%had previous spine surgery. 18% haddiabetes, 38% had CAD, 7% had COPD,and 12% were chronic steroid users. 47%were obese or morbidly obese. 363 levelswere treated: 263 1-levels, 35 2-levels, and10 3-levels. Grafting materials included acomposite of DBM, local bone graft, andbone marrow aspirate (69.1%), a beta-tricalcium phosphate/hydroxyapatite(FormaGraft) with bone marrow aspirate(9.7%), and allograft cellular bone matrixcontaining native mesenchymal stemcells (1.3%). All but two surgeriesincluded supplemental fixation, most

performed in the same surgical position.There were no transfusions or infections.Complications included 2 pneumonia, 1reintubation, 1 ileus, 2 urinary retention,1 atrial fibrillation, 1 endplate fracture(healed without intervention), 1 sacralfracture, 3 intraoperative hardwarefailures (replaced without incident), 1osteophyte fracture (requiredreoperation), 2 compression fractures(required vertebroplasty), and 1 quadweakness (resolved withoutintervention). Hospital stay averaged 1.1days. From pre-op to 24 months post-op,average disk height improved by 2.4mm,average slip improved by 7.4mm, averageVAS pain scores decreased by 5.8 points.Signs of fusion by Lenke scores of 1 or 2were 80% at 3 months, 94% at 6 months,and 99% at 12 months and 98% at 24months – not significantly different fromthe greater non-smoking (624 pts) cohort(84%, 95%, 97% and 98%, respectively).Conclusion:Our results show nosignificant difference in the clinical andradiographic outcomes between smokersand nonsmokers. MIS fusion approachesmay offset some of the deleterious effectsof smoking on bone healing.

397Use of Titanium Expandable VertebralCages in Cervical Corpectomy: A CaseSeriesClinton Judson Burkett, Fernando L. Vale,Juan S. UribeIntroduction:The purpose of this studywas to investigate the usefulness oftitanium expandable cages for vertebralbody reconstruction after cervicalcorpectomy. The authors describe aretrospective case series of patientstreated with expandable titanium cagesfor a variety of indications.Methods: 29 patients were treated withsingle or multilevel cervical corpectomyfollowed by placement of an expandabletitanium cage for spondylosis (13),trauma (9), infection (4), previoushardware failure (1), tumor (1), andarachnoid cyst (1). All patients wereevaluated clinically and radiographicallyat 6 weeks, 3 months, 6 months, and 12months. Cervical collars werediscontinued at 3 months.Results: 23 patients underwent single-level corpectomy (of which 5 were incombination with 1 level ACDF and 1 incombination with 2 level ACDF), 4patients underwent two-levelcorpectomy (of which 1 was incombination with 1 level ACDF), and 2patients underwent three-levelcorpectomy. Anterior reconstruction

alone was performed in 15 patients withsingle level-ACCF. Circumferentialreconstruction was performed in 16patients (9 single-level ACCF, 5 two-levelACCF, 2 three-level ACCF). All patientshad an anterior cervical plate placed. 1patient who had a C4 corpectomy andC5/6 ACDF with circumferentialreconstruction developed aretropharyngeal hematoma that wasevacuated on POD 2 and subsequentlydid well. There was evidence of fusion inall patients. There was no radiographicevidence of more than 2 mm subsidencethroughout the series. There were nooccurrences of instability or hardwarefailure.Conclusion:Our results show thatexpandable cages are useful in anteriorcervical corpectomies for providingadequate anterior column support andsolid constructs without significanthardware complications.

398Clinical Experience, Outcomes, andLearning Curve Following XLIF for LumbarDegenerative ConditionsJonathan Hyde, Solas Degenerative Study GroupIntroduction:Minimally invasive spineprocedures have been celebrated forreducing patient morbidity andexpediting patient recovery times.Despite these strengths, many minimallyinvasive techniques are associated withlong surgeon adjustment periods. TheXLIF approach has been shown to beminimally invasive with respect to bloodloss, hospital stay, and surrounding tissuedisruption, but uses familiarinstrumentation under directvisualization which minimizes theassociated learning curve.Methods:The records and radiographs of78 consecutive XLIF procedures wereretrospectively reviewed to assessperioperative and follow-up outcomesmeasures including operative time, bloodloss, hospital stay, complication rates,clinical, and radiographic outcomes. Asubset of single-level patients withoutrepositioning for posterior fusion wasexamined for evidence of an earlylearning curve.Results: Average patient age was 62.1 +14.0 years. Two-thirds of the cases weresingle-level procedures, but as many asfour levels were treated during a singleXLIF procedure. 95% of proceduresincluded posterior fixation. Average bloodloss was 109.9 cc (range: 10-650cc) andthe average operative time for all patientswas 221.0 min (range 78-489). Average




hospital stay was 2.7 days (range 1-7).One third (n=26) of patients experiencedtransient postoperative thighdiscomfort/dysesthesia. Of those patientswith CT evaluations 6 months or laterafter surgery (n=65), 100% demonstratedevidence of solid fusion. There were 8cases (10.3%) of implantsettling/subsidence which were notclinically significant. Evidence of alearning curve was identified with respectto reduced blood loss, and proceduretime over the course of the experience.Conclusion:The reduction in operativetime and blood loss over time in thiscohort was suggestive of a slight learningcurve; but even the earliest measureswere comparable or lower thantraditional open procedures. Relative totraditional open procedures, operativetime for XLIF procedures is shorter,intraoperative complications areuncommon, blood loss is minimal, andfusion rates are comparable.

399Predictors of Persistent Leg PainFollowing Minimally Invasive Surgery forLumbar RadiculopathyJohn W. German, Anthony G. ConteIntroduction:Minimally invasiveapproaches to the lumbar spine are beingincreasingly utilized with good efficacy.To further improve the clinical outcomesof patients undergoing surgery forlumbar radiculopathy all preoperativefactors should be considered todetermine which subset of patients are atrisk for doing poorly. Understandingthese risk factors can then be used toimprove the treatment paradigm.Methods: A retrospective review wasundertaken of 140 patients undergoingsurgery for lumbar radiculopathy.Medical records were reviewed and datawas abstracted for demographics, pastmedical history, past surgical history,psychiatric co-morbidities, neurologicco-morbidities, anatomic factors, andintraoperative factors. Six monthoutcomes were available for patientderived outcomes included leg visualanalog score (VAS). Outcomes wereanalyzed using the peri-operative changein which outcomes were classified assuccess (VAS>-2.0) or failure (VAS<-2.0)as well as a threshold method in whichoutcomes were classified as success(VAS<4.0) or failure (VAS>4.0). Statisticalanalyses included a t-test for continuousvariables and a Chi square test forcategorical variables with significance setat p<0.05.Results: Six month outcomes were

available for 56 patients. Using the peri-operative change method 18.1% ofpatients were classified as failures whilethe threshold method classifed 32%patients were classified as failures.Bivariate analysis of the leg VAS peri-operative change method suggests thatthe risk factors for failure were: femalesex, depression, and anxiety. Bivariateanalysis of the leg VAS threshold methodsuggests that the risk factors for failurewere: depression, presence of neurologicco-morbidity, absence of CSF leak,absence of foraminotomy, absence ofsequestrectomy, and absence ofannulotomy.Conclusion:Minimally invasive surgeryfor lumbar radiculopathy results in asuccessful outcome in 68 to 82% ofpatients at six months. The common riskfactor for persistent postoperative legpain using the two analyses methods is apreoperative self-reported history ofdepression.

400Vertex Distance Mapping as a Metric toDescribe Stability of the Lumbar SpineDennis Allen Roberts, Boyle C. Cheng,David M. Cook, Donald M. Whiting,Jonathan B. BellotteIntroduction: In contrast to rigid fixationfor spinal fusion, dynamic fusionprovides both immediate fixation andstabilization while allowing for anteriorload sharing. In allowing anterior loadsharing, compressive forces are applied tothe anterior construct, which shouldstimulate bone fusion. This studyinvestigated vertex distance mapping toevaluate facet motion on the dynamic vs.rigid construct as well as comparing it toan intact spine. Vertex Distance Mapping(VDM) measures the surface area withina specific region of interest (ROI) that fallunder a set threshold, here defined as 2mm within the ROI. Moreover, it thisproximity that may describe intimatecontact of facet joint surfaces andrepresent a proxy for stability.Methods: Six lumbar spine cadavericspecimens were stripped of all non-ligamentous tissue. Each spine was testedintact, with the Scientx Isobar TTLEvolution device at the L3-4 level, withthe dampener configured at low, mediumand high levels. A rigid construct wasthen applied and tested on the samespine. Three cycles evaluating axialcompression, flexion-extension bending,lateral bending and torsional testing wereperformed. Three cycles of each testingmode were performed andmeasurements were taken after the third

cycle. The difference in surface areameeting the threshold criteria of 2 mmwithin the ROI at the maximum andminimum standardized time points ofthe 3rd cycle were calculated.Results:The mean change and standarddeviation in flexion extension bending ofthe Isobar TTL in the middle positioncompared to the rigid rod construct was42.2mm±74.3mm and 34.0mm±44.7mmrespectively. There were no statisticallysignificant differences detected amongstthe treatment groups in any mode of loadsharing for the instrumented procedures.Conclusion:Dynamic fusion has twomain goals: 1) To provide immediatestabilization and fixation for a functionalspinal unit. 2) To allow for anteriorcolumn load sharing to facilitatearthrodesis. The vertex distance mappingof the facet of the intact spine, Isobarconstruct and rigid construct shows nosignificant change in facet interaction.From this study, we conclude that theisobar system does in fact provideadequate lumbar spine stabilizationwhile awaiting arthrodesis

401The Synergy Disc: 12-Month Clinical andRadiographic Outcomes for NextGeneration Artificial Cervical DiscKemal Yucesoy, Kasim Zafer YukselIntroduction:The Synergy Disc is a nextgeneration cervical artificial designed toprovide controlled, physiological range ofmotion with predictable and reliablelordosis control. The aim of this singlearm, prospective study was to assessclinical and radiographic outcomesfollowing single and multilevelprocedures.Methods: Patients were evaluatedpreoperatively and postoperatively at 1, 3,6 and 12 months. Evaluations at each visitincluded neurological examinations,clinical outcome measures and x-rays.Radiographic analysis, performed byMedical Metrics, Inc., evaluated thekinematics at the index level including:range of motion (ROM); translation; shellangles (SA); anterior and posterior discheights (ADH/PDH) and center ofrotation (COR).Results:Thirty-four patients wereenrolled at a single site study with fivepatients receiving 2 level procedures for atotal of 39 implanted discs. There was noadverse event or unsuccessful insertions.The NDI score decreased significantlyfrom 4.2 at pre-op to 1.3 at 3 months, 1.2at 6 months and 1.0 at 12 months. Theneck and arm pain VAS scores alsodemonstrated a significant decrease over




time (pre-op 8.0; 0.4 at 3 mos; 0.3 at 6 mosand 0.1 at 12 mos). Following surgery,there was no significant change in ROM(pre-op 12°; 12 mos 9.8°) or translation(pre-op 1.4mm; 12 mos 1.2mm) but anincrease in disc height (pre-op 3.5 mm;12mos 4.7mm). There was a minorchange in both COR X and Y values. Withrespect to the SA, the Synergy discmaintained a 6° lordotic configurationbetween the device endplates.Conclusion: Synergy disc is unique in itsability to provide predictable and reliablelordosis control while maintainingphysiological spinal kinematics. The 12-month data demonstrates excellentclinical safety and performance.

402Traumatic Thoracolumbar FracturesTreated with Short-Segment PedicleInstrumentationDavid Stidd, Jack H. Dunn, Michael Lemole, Rein AntonIntroduction: Early reports ofinstrumentation failure and kyphoticcollapse in the early 1990s led tocontroversy over the role of short-segment pedicle instrumentation for thetreatment of unstable single-levelthoracolumbar spine fractures. Theclassic teaching of extendingtranspedicular screw constructs 2 to 3levels above and below the fracturedspine segment was based on technologyfirst introduced in the 1980s. However,posterior transpedicular fixation hassince significantly evolved making longposterior constructs less necessarytoward the goal of boney fusion. Wereport a case series of patients thatpresented to single level 1 trauma centerwith an unstable single-levelthoracolumbar fracture treated withshort-segment pedicle instrumentation.Methods: A retrospective chart reviewwas conducted of twenty-two traumapatients with one or two level unstablethoracolumbar fractures. These patientswere treated with short-segment pedicleinstrumentation during the study periodfrom 2009 to 2010. Indications for surgerywere at the discretion of one of the threetreating senior authors. Both patientswith multiorgan injuries and isolatedthoracolumbar fractures were included itthis review.Results:The ages of the patients rangedfrom 17 to 66 and included 14 males and8 females. The mechanisms of injuryincluded 10 motor vehicle collisions, 8falls, 3 motorcycle collisions, and one ATVcrash resulting in 3-T12, 15-L1, 2-L2, 2 L3,and 1-L4 unstable fractures treated with

short-segment pedicle instrumentation.The average follow-up was 2.5 months.There was no evidence of instrumentfailure or signs of boney fusion failure onimaging obtained at follow-up.Conclusion:Thoracolumbar fracturescan be successfully treated with short-segment pedicle instrumentation usingcontemporary technology. No instrumentfailure was noted in this series. Lessimplanted instrumentation results in lesshealth care cost.

403Cervical Reconstruction Using LateralMass CagesMichelle J. Clarke, Ian Suk, Daniel M. Sciubba, Timothy F. Witham,Reza Yassari, Ali Bydon, Ziya L. Gokaslan,Jean-Paul WolinskyIntroduction: Recently, more aggressivesurgical techniques including en blocresections of certain tumors has resultedin a need for creative spinal columnreconstruction. Iatrogenic instability ofthe craniocervical junction or subaxialspine following these resections requiresa thoughtful approach to adequatelytransfer load-bearing forces from theskull and upper cervical spine to thesubaxial spine. At the craniovervicaljunction, axial forces are transmittedfrom the occipital condyles to the lateralmasses of C1 to the lateral masses of C2.This is the only portion of the spinal axisin which a central vertebral body doesnot provide the majority of support.Methods: A retrospective review wasperformed of the medical records of allfive patients who have undergone lateralmass cage placement at our institution.Lateral mass cages were used as acomponent of cervical spinereconstruction following iatrogenicdestabilization. All patient notes,operative records and imaging resultswere reviewed with a range of follow-up.In all cases described, the lateral masscage span was dictated by the extent oftumor resection and subsequentreconstruction needs.Results:We describe five cases of lateralmass cage placement. A case illustrationis used to describe the general technique,and we discuss how this technique andbe expanded for other indications. Wediscuss the surgical nuances of ourtechnique for lateral mass cageplacement. Additionally, we provide ourrational for the use of these constructsthroughout the craniocervical junctionand subaxial spine. Complications andoutcomes of this challenging techniqueare also discussed.

Conclusion: Reconstruction of the load-bearing capacity of the upper cervicalspine following large surgical resections ischallenging. This series demonstrateslateral mass cages used to provide load-bearing support, including one case ofbilateral cage placement in the face ofmajor iatrogenic instability.

404Use of rhBMP-2 to Augment PosteriorAllograft Fusions of C1-C2 and theCraniocervical JunctionBrian James Hood, Andrew L. Ross, Marine Dididze, Allan D. LeviIntroduction: Iliac crest autograft hasbeen the uncontested grafting techniqueof choice in posterior occipital-cervicaland atlanto-axial fusions due to itsosteoinductive and osteoconductiveproperties. New evidence has emergedthat suggests a modified allografttechnique [1] (graft placed in a trueinterpositional manner and held incompression between the posteriorelements of C1 and C2) in conjunctionwith instrumentation is able to producealmost equivalent fusion rates (88.9%allograft vs. 96.7% autograft at 24 months)while preventing the complicationsassociated with autograft harvesting [2].In order to augment the osteoconductiveeffect provided by the modified allografttechnique, rhBMP2 was used to induceosteocyte proliferation and improvefusion rates.Methods:We performed a retrospectivechart review of patient data including x-rays and fine-cut CT scans of patientswho underwent posterior instrumentedatlantoaxial or occipital-cervical fusionsusing allograft and BMP2 between 2007and 2010. A total of 22 patientsunderwent either C1-C2 (n=17) or O-C(n=5) fusions. Each procedure wassupplemented with either extra-small(n=2), small (n=18), or medium (n=2)aliquots of rhBMP-2.Results:The study group was 50% malewith an average age of 54 years (range 6-92). Diagnoses included type II odontoidfractures (n=7), rheumatoid arthritisrelated C1-C2 instability (n=7), O-C1-C2dislocations (n=2), C1-C2 facet arthrosis(n=2), and other (n=4). There were nocomplications directly attributable to theuse of BMP2 in all 22 cases (averagefollow-up 9 months). There have been nocases of reported hardware failure.Osseous union was achieved in allpatients (n=20) who achieved sufficientfollow-up. The rate of osseous unionappeared accelerated when compared tohistorical controls.




Conclusion:The fusion rate of achievedwith allograft and rhBMP2 comparesfavorably with previously describedautografting techniques.

405Spinal Synovial Sarcomas: A Series ofCases and Review of the LiteratureRoss Puffer, David J. Daniels, Caterina Giannini, Peter Rose, Mark A. Pichelmann, Michelle J. ClarkeIntroduction: Synovial sarcoma is a rare,aggressive neoplasm with uncertainorigins affecting mainly adolescents andyoung adults. Reports of synovialsarcoma arising from, near, or metastaticto the spine have been extremely rare.Methods:We retrospectively reviewed theMayo Clinic database and identified threepatients who were diagnosed and treatedfor spinal synovial sarcoma since 2004.Results:The three patients withpathologically confirmed synovialsarcoma included a patient with athoracic dumbbell tumor, a patient with aparaspinal tumor and the first report of apatient with leptomeningeal spread ofsynovial sarcoma. Recognition of a high-grade lesion was made intraoperatively inall cases, precluding en bloc resection. Allpatients underwent aggressive treatment;one patient had recurrence within 6months, another succumbed to anunrelated brain tumor within 4 months,and the final patient has no knowndisease at 3 years. There are 14 additionalcases of spinal synovial sarcoma reportedin the literature which we review,including 8 located within the paraspinalmusculature with most having foraminalextension (dumbbell shape), 3 associatedwith intradural spinal nerve roots, 2metastatic lesions (one to bone and oneintramedullary), and one primarybony/lytic lesion. The cases we present allinvolved the paraspinal muscles with twoof them being associated with spinalnerve roots (dumbbell shaped), the otherhaving significant leptomeningealassociation which is the first reported inthe literature.Conclusion: Surgical excision with wide,negative margins is the currentlyrecommended treatment with adjuvantradiotherapy and/or doxorubicin basedchemotherapy. While this is a mainstay oftreatment, there is no consensus on theoptimal treatment strategy. These tumorsare challenging to diagnosis, and laterecognition may hinder appropriatlyagressive initial resection. Thus clniciansmust consider these lesions in theirdifferential, especially in cases ofparaspinal tumors.

406Two-level Instrumented ACDF UsingDemineralized Bone Matrix and LocalBone: 184 Cases at 1 and 2-Year Follow-upW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:The complications andrates of fusion associated with the ACDFprocedure in use with demineralizedbone matrix are reported to demonstratethe feasibility, safety, and effectiveness ofthe approach. Clinical and radiographicoutcomes were evaluated to assesscomplications and fusion rates at 12 and24-month follow-up.Methods: 184 patients underwentinstrumented 2-level anterior cervicaldiscectomy and fusion procedures.Patients were assigned to one of twotreatments arms that included acomposite of DBM plus autogenousendplate reamings, incorporated intoallograft bone dowels or PEEK spacers.Fusion was defined as definitive,uninterrupted bridging of mineralizedbone across the interbody space and nosignificant motion on flexion-extensionradiographs. Both operative levels wereassessed for fusion using a modifiedLenke score. Any pseudarthrosis at eitherlevel was considered a failure.Results: 184 patients, 67 male and 117female, with average age of 56.0 years(range 31-81 years) presented for 12-month follow-up. To date, 60 patientshave presented for 24-month follow-up.Average 12-month Lenke score was 1.07,and average 24-month Lenke was 1.03There were no infections, neurologiccomplications or plate breakages. One59-year-old diabetic male smoker, had apseudarthrosis at the time of 6-monthfollow-up.Conclusion:The combination of a DBM-local bone composite contained withinallograft dowels or PEEK spacers anddynamic cervical plating resulted infusion in 183/184 patients at 12 and 24months postoperatively. Thiscombination achieved fusion resultscomparable to earlier literature reportsfor autograft or instrumented allograftdowels without the incumbent expenseand documented complications of BMP.

407Prospective Multicenter Evaluation ofPercutaneous Lumbar Pedicle ScrewPlacement Using the Oblique or “Owl’sEye” ViewCary IdlerIntroduction: Few studies have focusedon the oblique technique as a potentially

more accurate method of placingpercutaneous lumbar pedicle screwswithout direct visualization. Aprospective, randomized, IRB-approvedstudy was undertaken to evaluate theaccuracy and safety of the obliquetechnique using computer assistance tofacilitate orienting the C-arm into theoblique view efficiently and accurately.Methods: After providing informedconsent, patients were randomized intoone of two groups: one underwentplacement of lumbar pedicle screwsusing the oblique technique with theassistance of Guidance; the other groupunderwent screw placement per thesurgeon’s usual technique usingfluoroscopy alone (non-Guidance).Fluoro time, screw placement time, andEMG thresholds were recordedintraoperatively for both groups. A neuralexam and VAS pain assessment wereobtained pre- and immediately post-op.A post-op CT scan was also obtained todetermine screw placement accuracy.Results: A total of 47 patients (27 femalesand 20 males) have been enrolled to-date.Primary surgeries included instrumentedALIF (9), XLIF (18), and/or TLIF (22). Ofthe 214 screws evaluated post-op by CT,11 (5.1%) breaches occurred: 8 (3.7%)medial, 2 (0.9%) lateral, and 1 (0.5%)inferior; 10 of the 11 pedicle breacheswere less than 2mm in magnitude, and 1breach in the non-Guidance group was 2-4mm in magnitude. None of thebreached screws required revision, andthere were no significant differences inclinical improvements between patientswith breached screws (n=7) and thosewithout (n=40). Use of Guidance resultedin a statistically lower fluoro usage perscrew (p<0.001) and quicker placement ofguidewires (p<0.001). Although there wasno statistical difference in the averagetime it took to place each screw, averagetimes trended lower with the use ofGuidance (p=0.059).Conclusion:The oblique technique forpercutaneous pedicle screw placementusing NeuroVision Guidance providesfeedback on the appropriate targeting ofthe pedicle and successfully reduces theamount of fluoroscopy used withoutsignificantly adding to the time requiredfor placing pedicle screws.

408Clinical Outcome of Cervical Arthroplastyfor Adjacent Segment Degeneration AfterAnterior Cervical Interbody FusionKyoung Suok Cho, Sang Bok Lee, Pil Woo Huh, Do Sung Yoo, Tae Gyu Lee,Chun Kun Park




Introduction: Anterior cervicaldiscectomy and corpectomy for thetreatment of cervical spondylosis andcervical disc herniation enjoy favorablerates of fusion and successful clinicaloutcomes. However, postoperativedegenerative changes at adjacent discsmay lead to the development of newradiculopathy or myelopathy. In theprevious reports, the incidence ofsymptomatic adjacent segment diseasehas ranged from 7% to 25%. The presentstudy was undertaken to investigate theincidence of symptomatic adjacentsegment disease after anterior cervicalinterbody fusion (ACIF) and to describeour surgical method for those patients.Methods: Between 1999 and 2007, a totalof 165 patients underwent anteriorcervical interbody fusion forintervertebral disc herniation andcervical spondylosis. A total of 115 ofthese patients could be followed upclinically and radiologically for more than2 years (follow-up rate, 82%). Of these, 77were men and 38 were women and theaverage age at operation was 51 years(range, 26 to 75 years). The average lengthof follow-up was 5.8 years (range, 2 to 9years). The diagnosis of symptomaticadjacent segment disease was based onthe presence of new radiculopathy ormyelopathy symptoms referable to anadjacent level, and the presence of acompressive lesion at an adjacent level bymagnetic resonance imaging.Results: Symptomatic adjacent segmentdisease developed in 13 of 115 patients(11.3%) followed. We performed fusionextension three, fusion plus total discreplacement (TDR) one and only TDRnine patients. All patients were improvedafter surgery without any complicationexcept one transient hoarseness.Conclusion:The cervical arthroplasty is areasonable treatment option for patientswho have had previous surgery in whichinterbody fusion has been performed andwho have developed degeneration ofadjacent levels.

409The AOSpine ANEG (Access andNavigation Expert Group) Survey on theUse of Navigation in Spine SurgeryRoger Hartl, Khai Lham, Jeffrey C. Wang,Andreas Korge, Frank Kandziora, AOSpineIntroduction: Despite reports suggestingthat computer-assisted navigation (CAN)can improve accuracy of screw placementand decrease radiation exposure it is notwidely accepted among spine surgeons.We performed an internet-based surveyamong AOSpine surgeons in order to

better understand the current deficits ofnavigation.Methods: A 12-item questionnaire wasdistributed by e-mail to 3348 AOSpinesurgeons worldwide. The questionnaireasked for information on number andtype of surgical cases, the type ofnavigation equipment available andgeneral opinions towards navigation. Toinvestigate the existence of groups ofsurgeons based on their opinion profilewe applied the technique of latent classmodeling.Results: Response rate was 20% (678surgeons). Despite a widespreaddistribution of navigation systems inNorth America and Europe only 11% ofsurgeons use it routinely. High-volumesurgeons, neurological surgeons andsurgeons with a busy MIS practice aremore likely to use CAN. “Routine users”consider as the main advantages of CANits accuracy, the potential of facilitatingcomplex surgery and the reduction inradiation exposure. The same groupidentifies the increase in OR time as themain reason why they do not use CANmore frequently. The lack of equipment,inadequate training and high costs arequoted by the majority of “non-users” asthe main reasons for not using CAN.Overall, 79% of surgeons feel positivelyabout CAN and 37% have strong and verystrong positive beliefs about the benefitsof navigation.Conclusion:The majority of surgeonshave positive beliefs about navigation.However, the high costs associated withCAN systems, lack of access to navigationsystems, the increase in OR time and thelack of good scientific data supporting itsclinical benefits appear to be the mainreasons why surgeons do not use CAN ordo not use it more frequently.

410Surgical Management of TraumaticFractures of the Upper Thoracic SpinePaul M. Arnold, Brett C. Ebeling, Karen K. AndersonIntroduction: Management of traumaticupper thoracic spine fractures (T1-T6) iscomplicated by unique biomechanicalcharacteristics and the nature of theinjuries, which are often associated withmultiple comorbidities as well as completespinal cord injury. The goal of our studywas to report further evidence of thesafety and efficacy of surgical treatmentto achieve and maintain reduction ofupper thoracic spine fractures.Methods:This study was a retrospectiveanalysis of traumatic unstable upperthoracic spine fractures treated at our

facility between 1994 and 2009.Preoperative evaluation includedneurological exam and radiographicanalysis. Surgical indications were basedon spinal instability, neurological status,and other patient factors. Clinical andradiographic outcomes includedneurological deficit, hospital and ICUlength of stay, kyphotic deformity andsuccessful reduction of fractures.Results: 35 patients (19 male, 16 female),with mean age of 38.1 years (range 14-83years) were included in the study.Reduction and stabilization of thefractures was achieved using either hookand rod constructs or pedicle screws androds. There were 165 total levels fixed,with no intraoperative complications.Hardware was removed post-fusion (1-3years) in five patients due to pain, woundinfection, or hardware failure. A sixthpatient had hardware replacement afterthree days due to suspicion of screwmigration. All patients in this studybenefited from successful reduction oftheir fractures, and none of the patientssuffered further neurological dysfunctionas a result of the procedure. The averagehospital length of stay was 13.8 days(range 4-53 days).Conclusion: Surgical treatment of upperthoracic spine fractures, althoughcomplex, is safe and effective. Reductionand fixation of these fractures results inreduced risk of further neurologicaldamage due to the injury, and allows forearlier mobilization, which correlateswith shorter hospital lengths of stay andimproved patient outcomes.

411Spondylolysis without Spondylolisthesis:A Missed Diagnosis by MRIBennett Blumenkopf, Jonathan B. Bellotte,James BurgessIntroduction: Lumbar MRI has becomethe imaging study of choice for theevaluation of low back pain, especially inthe primary care setting. Spondylolyis isamong the etiologies of low back pain,particularly in adolescents and athletes.While MRI provides superb soft tissuedetail, its capability in detecting fineosseous changes, such as spondylolysis, isless clear; failure to do so may result indelays in referrals by the primary carephysicians.Methods:The formal MRI reportsauthored by board-certified radiologistsof 13 consecutive patients with surgically-verified spondylolysis were reviewed,retrospectively, for any mention ordiscussion of spondylolysis. The imagesthemselves were also reviewed by the




operating surgeon at the time of initialclinical presentation. Reports were alsoreviewed for mention ofspondylolisthesis, and compared toformal radiology CT scan reports, as well.Results: Six of the 13 radiologists made nomention whatsoever of spondylolysis.Some of the highlighted features includedin their reports were disk degeneration,facet arthropathy, and stenosis. Five ofthese patients did not havespondylolisthesis noted in the report.Seven reports characterized the findingboth in the discussions and impressions;6 also noted spondylolisthesis. (p <0.03,Fisher’s exact test). The neurosurgeonrecognized/inferred the defect in all casesduring the first examination. Secondarylumbar CT confirmed that impression inthe 6 false negative by MRI instances.Intraoperatively, the pars interarticularisdefects were unequivocal; a Gillprocedure was performed in all 13 cases.Conclusion: Spondylolysis withoutspondylolistheis proved to be adiagnostic challenge for board-certifiedradiologists utilizing MRI. MRI may notbe the imaging study-of-choice for somepatients with chronic back pain,especially in the adolescent primary careand sports medicine settings. As such, analternative/supplemental evaluation witheither CT or SPECT may be appropriate.

412Clinical Indications for Arterial Imaging inCervical Spine TraumaMatthew J. McGirt, J.E. Evin, J.Y. Lee, Clint DevinIntroduction:Cervical spine injuries thatinvolve displacement of the cervical spineor injuries that present with neurologicdeficits warrant further evaluation witharterial imaging. Cervical spine injuriesare very common in high energy traumaand are frequently seen at level onetrauma centers across the country. Aclinical standard of care does not existindicating when further evaluation of thecervical vasculature is warranted after adocumented cervical spine injury.Methods: After IRB approval, aretrospective study combining the datafrom two level one trauma centers wasundertaken. An evaluation of everyarterial imaging procedure(computerized tomography andmagnetic resonance arteriography) of thecervical spine was collected to furtherdelineate indications and outcomes ofthese imaging modalities.Results: From 2005 to 2009 there were atotal of 159 patients who underwentcervical arterial imaging at the two

participating institutions for theindication of cervical trauma withconcern for arterial injury. Thirty-six(22.64%) were found to have an injuryfollowing arterial imaging. There was astatistically significant correlation withdisplaced cervical injuries (p < 0.0153)which were defined as cervicaldissociations, perched, and/or jumpedfacets. The other statistically significantcorrelation was the presence of aneurological deficit (p < 0.001), defined asany presenting deficit of the sensory ormotor physical exam. Level of injurydefined as axial (O-C2) vs. subaxial (C3-C7), age, BMI, and history of cigarettesmoking were not statistically related tovascular injury.Conclusion:Our retrospective evaluationindicates that there should be a lowerthreshold for obtaining arterial imagingwith cervical injury patterns historicallyknown to compromise the vasculaturethat also have concomitant displacedcervical spine injuries and/or aneurological deficit.

413Revising the Impact of Athletic Activity onCervical and Lumbar SpineLaura Ganau, Nikolaos Syrmos, Mario Ganau, Igor Faquini, Dimitrios ArvanitakisIntroduction:The diffusion of athleticactivity in the general population hasincreased markedly over the last 30 years;wellness seems to give hope for anhealthy future, nevertheless the long-term effects of this widespread attitudeare still debated.Methods:To assess the impact of sportactivity in an asymptomatic population oflifelong athletes we have enrolled 40sports-men and women (ratio m/f 1:1) inthe present study and performed for eachof them an MRI scan of the cervical andlumbar spine. Degree of cervical andlumbar spondylosis, as well as presenceof disc degeneration, herniations, type ofModic changes, and indirect signs ofsegmental instability were assessed.Neuroradiological data were matchedwith the athletic history, and comparedwith the incidence of spinal degenerativediseases in the general population asreported in literature.Results: Evidence of asymptomatic spinaldegenerative diseases on MRI scans wasas high as 35%; and included: cervicaldisk protrusion (2.5%), cervicalspondylosis (10%), lumbar diskprotrusion (12.5%), lumbar diskherniation (2.5%), lumbar instability(2.5%), lumbar stenosis (5%). Incidence

increased proportionally with aging andBMI, without gender differences. Allfindings proved to be asymptomatic anddid not interfere with athletic activity.Conclusion:The incidence ofdegenerative spinal diseases in athletesseems to be similar to that seen in thegeneral population. Although the smallsample did not allow for a statisticalanalyses, it seems that athletic activityshould not be considered a prioriprotective against the patho-physiological degeneration of spinalelements, certainly neither it should beconsidered a risk factor.

414XLIF at L4-5 and the Protective Effect ofProphylactic DexamethasoneW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction: It has been reported thatXLIF procedures performed at the L4-5level have a higher incidence ofpostoperative motor deficits compared toother lumbar segments, and mustoccasionally be aborted to due anatomicconstraints.Methods: In our single-site consecutiveseries of 941 XLIF patients, 565 (60%)included the L4-5 level. Clinical andradiographic data were prospectivelycollected and reviewed to assess XLIFprocedure at the L4-5 level.Results: Age averaged 62.0 years (24-88years). 78.1% had one or morecomorbidities. 31.0% had prior lumbarsurgery. All procedures were successfullycompleted. Hospital stay averaged 1.2days. Average VAS pain scores improvedfrom 8.7 at pre-op to 2.4 at 12 months and2.2 at 24 months follow-up. Lenke fusionscores of 1-2 were present in 96.8% at 6months, and 99.0% at 12 months. Neuralcomplications included 4 (0.6% of allcases, 0.9% of L4-5 cases) transient lowerleg weaknesses (3 quads, 1 anteriortibialis; all resolved within 3 months).After the fourth postoperative motordeficit, we began to administerdexamethasone (10mgIV prior to skinincision) prophylactically in all XLIFpatients in whom the L4-5 level was to beapproached. Since the use ofdexamethasone, no additional neuraldeficit developed, a statisticallysignificant difference (p=0.0245).Conclusion:The incidence ofpostoperative motor deficits followingXLIF at L4-5 is low. The prophylacticadministration of dexamethasone resultsin a statistically significant reduction inmotor deficits.




415Minimally Invasive Surgical (MIS)Method for Simplifying Sacroiliac JointArthrodesisMark Reiley, Fred H. Geisler, David W. Polly, Jr., Leonard M. Rudolf,Arnold Graham-Smith, John Jay Halki, W. Carlton Reckling, A. Nick ShamieIntroduction:Treatment focus in spinehas centered on lumbar pathology. 15-30% of individuals presenting with lowerback complaints had SI joint (SIJ)problems. The incidence of SIJdegeneration is 75% in patients withprevious L4-5 or L5-S1 fusions. An MISprocedure may help to address thissignificant unmet clinical need. An MISimplant was developed requiringminimal incision using fluoroscopicguidance. The implants are coated withporous plasma spray creating aninterference fit to decrease implantmotion. Because of size, geometry, andmetallurgy, they provide immediate post-op fixation accomplishing the goal ofopen SIJ fusion through an MISapproach.Methods:Diagnoses require appropriateinterpretation of patient history, clinicalexam, and imaging studies (often hip andlumbar pathology coexists with SIJpathology). If Lidocaine is injected intoSIJ and symptoms temporarily resolve,this is excellent confirmation ofdiagnosis. MIS procedure is performedunder general in prone position withimplants inserted through 3cm incision.Patients are implanted with three MISimplants across SIJ. A CT isrecommended at 3, 12, and 24 months todocument implant position and toobserve potential bone growth.Results:This retrospective, post-marketanalysis covers 52 patients. Patientsatisfaction tests were utilized. Clinicalsignificance was consistently good forpatients participating in assessments at 6and 12 months post-op vs. pre-op. 90% ofpatients indicated they would have theprocedure again.Conclusion:This study reinforces theneed for awareness that SIJ issues,including fracture, disruption ordysfunction, are common symptomgenerators. Traditional treatments haveshown limited efficacy. In some patientswith residual symptoms after lumbarspine procedures, it may be the SIJ that isthe symptom generator. With the adventof this MIS procedure, surgeons mayavoid further, unnecessary surgery forfailed lumbar fusion patients by lookingat SIJ. Multicenter prospective studies areongoing.

416MR Guided HIFU for Facet Joint Ablation,A Novel Approach for the Treatment ofBack Pain: Results of Preclinical StudiesSagi Harnof, Arik Hanannel, Lilach Shay,Oded Goren, Yael Inbar, Israel CaspiIntroduction: Facet joint arthropathy is acommon source of back pain. Currentlythe best treatment is RF ablation. MRGuided High Intensity FocusedUltrasound (MRgFUS) is a novelbreakthrough technology enables a non-invasive accurate ablation controlled byreal-time MRI based thermometry. Wehave conducted the project to evaluatethe feasibility of MRgFUS basedtreatment to achieve an accurate and safeablation of the facet joint. Hypothesis wasthat under MR guidance andthermometry we will be able to developan accurate and safe application.Methods:The feasibility and safety ofMRgFUS was evaluated in fourindependent experiments: A phantomtest in which thermal rise was measuredby MR Thermometry in the close vicinityof embedded vertebra. Thermocoupleexperiments to provide an absolutetemperature readings in the target andpotential safety hazards. An animalstudies in which treatment was applied tothe Facet under real time thermometry,follow-up includes imaging, histologyand clinical evaluation. Simulation wasdone on healthy human to validateanimal result. All experiments were doneutilizing the ExAblate2000 system.Results: Phantom experiments showedthat targeting the facet to elevate thetemperature is feasible with high safetyprofile, thermocouple experimentsshowed local temperature rise at thetarget with no rise at the spinalcanal/foramina. Animal studies targetingthe Facet at 150-400J resulted incontrolled local heat with insignificanttemperature rise at the spinal canal andforamina, clinical follow-up wasinsignificant, imaging and histologydemonstrated local thermal ablation atthe target without any remote damage.Human spine found to be similar to planand treat.Conclusion:This experiments hasshowed that ablation of the facet joint canbe done in this non-invasive methodswith accurately to create local ablation.MR guidance is extremely useful andenables real time temperaturemeasurements to control efficacy andsafety. With the promising results of thosepreclinical studies a human phase I studyis warranted.

417Does Reconstruction of the AnteriorLongitudinal Ligament (ALL) Improve theResults of Lumbar Artificial DiscReplacement (ADR)?Kenneth Pettine, Christian SchlichtIntroduction:The ALL is the mostimportant stabilizer of the lumbar motionsegment. Several authors have reportedthe most common reason for ADR failureis facet pain. Biomechanical datarepeatedly emphasizes the importance ofthe ALL in decreasing facet forces. TheEmbrace™ is a flexible implant designedto duplicate the biomechanics of the ALL.Biomechanical analysis of the Embrace™is performed by Cunningham, et al. TheCharité and ProDisc-L lumbar ADRs wereevaluated before and after reconstructionof the ALL with Embrace™. Axial rotationand extension were significantlydecreased (p>0.05) followingreconstruction of the ALL. Facet micro-strain was also significantly decreased.Methods:Thirty-nine patients underwentADR followed by ALL reconstruction.Minimum follow-up was one year.Charité - 24 patients, ProDisc-L - 15patients. Average age: 38.8 Males - 19,Females – 20. Average BMI - 27.5. One-level ADR - 27 patients, two-level ADR - 6patients. Two-level hybrid - 4 patients,three-level hybrid - 2 patients.Results: See chartsConclusion:Overall clinical success(based on Purcell FDA criteria) was metin 70% of patients at 6 months and 74% at12 months. There were no differences inthe outcome data between ProDisc-L,Charité, one-level, two-level or hybridpatients. These results are superior to theone-level IDE data reported in the Charité(63% success) and ProDisc-L (63.5%success).

418Neuronavigation for Minimally InvasiveTransforaminal Lumbar Interbody Fusion:Radiographic and Clinical ResultsJorge Torres, Harry H. Gebhard, Apostolos Tsiouris, Christian Geannette,Roger HartlIntroduction: It is unclear if minimallyinvasive TLIF (mTLIF) outcomes arecomparable to open TLIF. In addition,accurate pedicle screw placement usingMIS techniques can be challenging andrequires heightened reliance onradiographic guidance. The use ofnavigation systems combined with 3Dfluoroscopy may be helpful in this setting.The aim of this study was to reviewoperative parameters, clinical and




radiographic outcomes in a series ofpatients undergoing mTLIF with Iso-C3DNavigation (3D-NAV) assisted minimallyinvasive pedicle screw instrumentation.Methods: 53 patients who underwent 3D-NAV assisted mTLIF were reviewed.Clinical and radiographic data wereanalyzed. Clinical outcomes wereassessed with the Oswestry disabilityindex, visual analog scale and Mac Nabscores. Radiographic outcomes wereassessed using plain radiography andthin-slice CT.Results:The mean age at time of surgerywas 56.4 years. 178 screws wereimplanted with a total of 16 pediclebreaches (8.99% misplacementrate/91.01% accuracy rate). Radiographicfusion rate at a mean follow-up of 16months in patients with bilateral pediclescrews was 91.7% (vs. unilateral screws64.3%). No revision surgeries werenecessary. At 11±6.9 months there was amean improvement of 4.28 points in theVAS for back pain and 4.5 points for legpain. Mean ODI improved 12.43 points.The mean post-op disc height gain was4.84 mm and the mean post-op discangle gain was 2.87 degrees. There was acorrelation between a greater disc spaceheight gain and lower postoperative legpain and VAS score.Conclusion: Minimally-Invasivetechniques and neuronavigation areevolving fields within spinal surgery. Ourdata support the conclusion that 3D-NAVis safe and effective and combined withmTLIF can lead to results comparable toopen TLIF surgery, while offering thepotential advantages of lessened tissuetrauma, reduced blood loss, less radiationexposure and shorter length of stay.

419Clinical Usefulness of Intraoperative O-Arm in Minimally Invasive CervicalMicroforaminotomyJin-Sung Kim, Sang-Ho Lee, Ho-Yeon Lee,Sang Soo Eun, Sun Kwon, David Del CurtoIntroduction:This study was done todescribe the surgical technique andclinical results of minimally invasiveanterior transcorporeal or posteriorlaminoforaminotomy assisted by an O-arm-based navigation system for thetreatment of unilateral radiculopathy dueto foraminal disc herniation or foraminalstenosis. Anterior transcorporeal orposterior laminoforaminotomy arepromising minimally invasive techniquesfor treating radiculopathy caused byforaminal disc herniations with orwithout foraminal stenosis. Their majorbenefits are avoidance of fusion, thus

preserving mobility and stability, andreduced postoperative neck pain.Methods:Twenty-four patientsunderwent anterior assisted bytranscorporeal foraminotomy (ten) andposterior aminoforaminotomy (fourteen)using O-arm navigation using the Metrixtubular retractor. Main symptoms wereunilateral radicular arm pain withoutaxial complaints. Most of them had slightto moderate arm weakness. Study imagesshowed foraminal herniated discs and/orforaminal stenosis in one or twosegments. All patients with central discherniations or spinal canal stenosis, andsymptoms of myelopathy orradiculomyelopathy were excluded fromthe study.Results: Successful relief of radicular painwas achieved in all twenty-four patients.There were no cases of instability orrecurrence except one patient whounderwent anterior transcorporealforaminotomy. This patient showed discheight loss and angular instability due toviolation of disc space and uncovertebraljoint. Owing to intraoperative feedback tosurgeon, 8 out of 24 patients (33.3%)underwent additional foraminotomyafter checking the patients using O-arm.The peri-operative complicationsobserved were a dural tear in one patient,which was adequately treated with fibringlue and bed rest and postoperativewound hematoma in one patient. Theduration of the symptoms was 7.6months on average. The operation timewas 128 minutes on average. Additionaltime for the image guidance surgerybased on O-arm based navigation wasabout 25 minutes on average.Conclusion: Anterior transcorporeal andposterior microforaminotomy assisted byO-arm-based navigation is a safe,effective and minimally invasiveprocedure in the treatment of foraminalcompressive diseases of the cervicalspine, and offers the advantages ofpreserving segment mobility and stabilitywith decreased postoperative pain andearly return to normal activity.

420Fluroscopically-Guided Percutaneous IliacScrew Placement: Initial ClinicalExperience with 17 CasesMichael Y. Wang, Seth Williams, Praveen V. Mummaneni, Jonathan D. ShermanIntroduction: Percutaneous pediclescrews have become an accepted methodfor segmental fixation in a variety ofsettings. However, fixation to the pelvis,which offers unique biomechanical

advantages, has remained elusive from aminimally invasive approach. This reportdescribes our initial clinical experiencewith minimally invasive iliac screwplacement using a fluoroscopictechnique.Methods: A retrospective review wasundertaken for patients undergoingpercutaneous iliac screw placement overa period of 24 months. A total of 17patients (mean age =53 + 13 years) weretreated in this manner at threeinstitutions, using primarily X-Ray guidedscrew insertion (obturator outlet viewtechnique). Indications for surgeryincluded trauma (N=10), deformity(N=3), infection (N=2), and neoplasia(N=2). All patients underwent earlypostoperative CT scanning to determinethe accuracy of screw positioning withinappropriate anatomic confines.Results: A total of 33 cannulated screwswere placed for fixation in thelumbosacral spine using a fluroscopicallyguided technique. Fixation was to L1(N=1), L2 (N=5), L3 (N=2), L4 (N=6), andL5 (N=3). Additional iliosacral screwplacement was utilized in two cases.Intraoperative blood loss averaged 510 +784 cc, and total operative time onaverage was 235 + 170 minutes. Screwdimensions varied between 7.0-9.0 mmin diameter and 65-100 mm in length. Allof the percutaneous screws were placedappropriately as verified by postoperativefine cut CT scanning, and there was noevidence of any bony violations or sciaticnotch encroachment. Complicationsincluded a 75-year-old patient suffering asacral fracture who died of unknowncauses on postoperative day 10.Conclusion: An image-guided techniquefor iliac screw placement can beperformed safely with a low likelihood ofbony violation. This technique offersunique advantages for stabilization of thelumbosacral junction and represents asignificant advance in the field ofminimally invasive spinal surgery.

421Degree of Correction of Cervical KyphosisUsing Sub-axial Facet OsteotomiesNathaniel P. Brooks, Sharad Rajpal,Edward C. BenzelIntroduction: Symptomatic cervicalkyphosis can be difficult to treatsurgically requiring multiple surgicalapproaches to achieve a satisfactoryresult. Improved lordosis has been shownto be associated with less propensity forfurther degeneration and improvementsin myelopathy.(1) There are multipletechniques to correct a cervical deformity




including ventral and dorsal approaches.The degree of correction obtained with abilateral facet osteotomy in the sub-axialcervical spine is not well described. Thegoal of this study is to evaluate the degreeof correction obtained using facetosteotomies in the sub-axial cervicalspine.Methods:This a retrospective review ofthe senior author’s cases. Eight patientswere candidates for the study. They had adorsal only approach for cervicaldeformity correction with facetosteotomies in the sub-axial cervicalspine for myelopathy and/or neck pain.Two of the patients died peri-operatively,one from a ruptured colon and the otherfrom myocardial infarction, and were notincluded in the study. Therefore, a total ofsix patients were enrolled in the study toevaluate initial correction. Only fivepatients completed at least 12 months offollow-up. Pre and postoperative uprightlateral radiographs were used to measurethe angle of intersection of theperpendicular to the inferior endplate ofC2 and C7 (Cobb angle), as described byGwinn et al.(2) The measurements wereobtained by two fellowship trained spinesurgeons.Results:The initial average degree ofcorrection per level was 11 degrees (SD =10.8 deg). The degree of correction perlevel with a minimum of 12-monthsfollow-up was 10 degrees (SD = 8.7degrees).Conclusion:Dorsal facet osteotomy inthe sub-axial cervical spine can be usedto obtain lordotic correction of thecervical spine. Care must be taken asthese patients have significant morbidityand mortality associated with cervicaldeformity correction by any technique.

422Outcomes of MIS Spinal Fusion: 12 and24 MonthsW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction: XLIF outcomes at 1 year arepresented and are compared with initial 2year data.Methods:Consecutive series of 941 XLIFpatients, 451 follow-up at 12 months and191 at 24 months. Clinical andradiographic measures wereprospectively evaluated to assess painscores, changes in disk height andalignment, listhesis, and fusion andcorrelated to a patient questionnaire ofsatisfaction at 12 months.Results: Age ranged from 25-87 years (avg 62.7 yrs). VAS improved from 8.8 pre-op to 2.9 at 12 months. Disk height

improved from 6.7mm to 10.8mm atpost-op, settling about 1mm to 9.4mm by12 months. Listhesis was reduced from4.5mm to 0.75mm, maintained at 12months. Definitive signs of fusion (Lenke1-2) were present in 87% at 3 months,96% at 6 months, and 98% at 12 months.In the 2 year group, VAS was reducedfrom 8.6 to 2.7, disc height gained wasmaintained at 12 and 24 months(9.1mm). Slip reduction was also similarand maintained at 24 months (0.8mm).Signs of fusion were present in 98.8% at24 months. At 12 months, 88% were verysatisfied or satisfied with their surgery.89% would definitely or likely do thesurgery again. 77% were consideredexcellent or good outcomes by thesurgeon.Conclusion:Our data shows satisfactoryintermediate term clinical outcomes inour series of XLIF. VAS scores improved,disk height was restored and maintained,and slip was reduced. Patient andsurgeon satisfaction scores at 12 monthsare encouraging.

423Clinical Significance of Hypermobility inCervical Artificial Disc ReplacementsKenneth Pettine, Christian SchlichtIntroduction:Normal range of motion interms of total flexion/extension at C4-5averages 18.8º, C5-6 averages 18.4º andC6-7 averages 15.4º. Cervical artificialdiscs have been designed to emulatenormal spine kinematics. The Prestige STand the ProDisc-C are designed to allow10º of flexion from a neutral position and10º of extension for a total 20º of range ofmotion. The Bryan allows 22º total rangeof motion.Methods: Published FDA IDE data wasevaluated from the Prestige ST, ProDisc-Cand Bryan disc in terms of range ofmotion at the operated level. Internalanalysis of these hypermobile patients byeach company revealed no difference intheir FDA success. Preoperativeflexion/extension views do not correlatewith patients who post op develophypermobility. Overall range of motion ofthe entire cervical spine remains withinnormal limits in these patients. Thus,more motion is occurring at the cervicalartificial disc replacement than adjacentlevels which may decrease the incidenceof adjacent level degeneration. This isopposite compared to fusion.Results:Histograms of the Prestige ST,ProDisc-C and Bryan disc indicate 15% ofPrestige ST patients, 24% of ProDisc-Cpatients and 6% of the Bryan disc patientshad greater than 14º of total motion in

flexion/extension. These results are basedon a single flexion/extension x-ray at two-year follow-up. In terms of the totalgroup, these patients are considered tohave hypermobile cervical artificial discs.Conclusion:The average range of motionreported after CADR is 8º of totalflexion/extension, substantially less thanthe 15-18º considered normal range ofmotion. If the goal of artificial discs is toemulate normal spine kinematics,hypermobility may be a desirable result.At two-year follow-up no conclusions canbe made whether these hypermobilepatients demonstrate long-term clinicaladvantages.

424Evaluation of Interlaminar LumbarInstrumented Fusion (ILIF) in a SheepModelHyun BaeIntroduction: Every year nearly 100,000spinal fusions are performed to treatdegenerative conditions of the lumbarspine. Various surgical techniques areutilized to eliminate motion andinstability at a diseased lumbar segment,each with its intrinsic surgical advantagesand disadvantages. The most frequentlyutilized surgical techniques includeinterbody arthrodesis and posterolateralfusion, and less commonly, but growingin popularity, interlaminar/interspinousfusion procedures.Methods: 8 sheep received aninterspinous process translaminarprocedure at L2-3 and L4-5 and weregrouped into two different treatmentcategories: Group I with a biologic in alllevels and Group II with allograft spaceronly in all levels. Specifically, Group I:(n=4) allograft spacer with biologic with aspinous process plate, or allograft spacerwith graft material alone; Group II: (n=4)allograft spacer together with a spinousprocess plate, or an allograft spacer alone.Upon euthanization, the spines wereexplanted and a full histological andradiographic (radiographs and CT)evaluation was conducted to assessfusion.Results: 16 spinal levels were treated.Histological and radiographic reportsdemonstrated that the specimensimplanted with a spinous process plate,allograft spacer, and biologic showed thepresence of bridging bone and graftremodeling, while the specimens withouta biologic were incompletely fused. Bonyfusion was unequivocal in 4/4 of theoperative levels in the interspinous plate+bone allograft+biologic group. Bonyfusion was seen radiographically in 2/4 of




the operative levels in the interspinousplate+bone allograft group. In theallograft+graft substrate group (no plate),fusion was apparent in 4/4 of levels and2/4 fused in the allograft only group.Conclusion: ILIF is a less disruptiveapproach to traditional instrumentedposterior lumbar decompression andfusion. Based on the sheep model, thisprocedure results in a fused segment inthe lumbar spine when treated inconjunction with an allograft spacer, aspinous process plate, and a biologic.

425Redesigning A K-Wire Limits InadvertentAdvancement: A Biomechanical StudyCarolyn Hardin, Joshua E. Preiss, Sergio Gutiérrez, Robert E. IsaacsIntroduction:The migration of K-Wires isa well-known complication that canoccur with potentially catastrophicconsequences. This study investigates aguidewire technology designed toincrease the force it takes to advance a K-Wire after it is deployed.Methods: A biomechanical study wasdesigned to test the force required todisplace the guidewire through bothcancellous and cortical bone. Guidewireswere placed at every vertebral levelbetween L1 to L5 in human cadavericspecimens. The design was internallyrandomized between a standardguidewire and a Y-Wire™, allowing eachvertebra to serve as its own control.Displacement and axial load weremeasured. The regions of interest werethe mid-vertebral cancellous bone andthe anterior cortical wall.Results:The force for a standard wirestayed roughly the same throughout thecancellous bone tested (p=0.83). Incontrast, the force to advance a Y-Wire™increased in a linear fashion. The mediancancellous force values exceeded 400% ofthe values obtained from a standardguidewire (435%, range 272%-2136%).The force to displace a Y-Wire™ exceededthe cortical values obtained in the samevertebra after it was deployed 5.0 mm(range 1.0-8.4 mm). Additionally, theforce required to breach the anteriorcortex with a Y-Wire™ was 219% greaterthan a standard guidewire (p<0.001,range 184%-7129%).Conclusion:Y-wire™ offers the ability toincrease the push-in force to advance aguidewire placed into cancellous bone tovalues that exceed the force which causestandard guidewires to break through theanterior cortex. By altering the distal tipdesign of a guidewire, Y-Wire™substantially decreases the chances of

inadvertently advancing a guidewireaway from its desired location.

426A Systematic Review of Accuracy andComparison of Intraoperative Biplanar andVolumetric Image Guidance SystemsAlan T. Villavicencio, Alexander Mason,Ewell Lee Nelson, Sharad Rajpal, Frances A. Carr, Brittany Weeks, Sigita BurneikieneIntroduction: Intraoperative spinalnavigation has evolved to allow surgeonsthe ability to utilize real timevisualizations of the surgical site. Theliterature reports comparably low rates ofpedicle screw misplacement usingvolumetric three-dimensional navigation,but greater accuracy is inherentlyassociated with increased radiationexposure. The study was undertaken toexamine the accuracy of pedicle screwplacement and compare two-dimensional and volumetricintraoperative image guidance systemsusing a systematic literature reviewmethod. This method will allow us tomake more generalized conclusions andpotentially justify increased radiationexposure for the tradeoff of screwplacement accuracy.Methods: A PubMed literature search wasconducted to explore published literaturethat focused on the accuracy of pediclescrew placement using intraoperativeimage guidance in clinical settings. Thesearch identified articles that analyzedaccuracy of volumetric and biplanarimage guidance systems.Results:We analyzed 32 studies withcollected data from 1991 to 2008. Thestudies totaled 8,072 pedicle screws and,of these, 7,278 were placed accurately,yielding a total of 90.2% accuracy rate.When comparing accuracy of the twosystems, there was a significantly higherrate of misplaced screws when two-dimensional navigation was employed(?2=206.85, df =1, p < 0.0001). Out of thetotal of 794 misplaced pedicle screws,73.3% (582) were misplaced using two-dimensional imaging system comparedto 26.7% (212) using volumetricintraoperative image guidance systems.Further, 14.7% of the total screws placedutilizing biplanar fluoroscopy weremisplaced vs. a misplacement rate of5.2% of the total volumetrically placedscrews. The accuracy of pedicle screwplacement between the levels of thevertebral spine resulted in theidentification that there were moremisplaced screws in the thoraciccompared to lumbar and lumbar spine

(?2= 81.23, df = 2, p < 0.0001).Conclusion:The results of this studysuggest a significantly greater rate ofpedicle screw placement accuracy whenvolumetric intraoperative navigation isused. This increased accuracy is noted inall levels of the vertebral spine.

427Stabilizing the Spine Following DiscHerniation: A Feasibility Study of a NewTechniqueWerner Schmolz, Daniel B. Murrey, Finn Christensen, Bruce RobieIntroduction: 60% of patients with discherniations have significant back painpreoperatively[1], and back pain has beenassociated with excessive axial rotation[2,3].A device that resists axial rotation mightpositively impact low back pain. Adynamic stabilization device resists axialrotation and consists of a speciallydesigned suture anchor, a high strengthsuture and a button, placed parallel to thedisc space (Fig. 1). The purpose of thisexperiment was to determine whetherthe ARO would restabilize the spine inaxial rotation without impacting othermotions following a herniation.Methods: Lower lumbar spine cadaverspecimens were tested in a six DOF spinetester. Four specimens were tested intact,with a unilateral incision through theposterolateral annulus (herniation), thenwith the stabilization device. Loads wereapplied in flexion, extension (F/E),bilateral lateral bending (LB), andbilateral axial rotation (AR-A - away fromthe herniation, and AR-T - towards theherniation). Displacements weremeasured. Results were reported asmedian percent of intact motion.Results:The simulated herniationincreased motion in AR-A to 115% ofintact. Lesser impacts were in lateralbending (LB) (108%), AR towards (AR-T)the herniation (107%), and F/E (102%).The device restored stability in AR-A (96%of intact) and had minimal impact in F/E,AR-T and LB (99%, 104% and 105% ofintact, respectively).Conclusion:The results show that theARO successfully resisted excessive axialrotation resulting from a modelherniation, while having minimal impactin other directions. The results areconsistent with previous testing ofcadavers with and withoutherniations[4,5]. As low back pain hasbeen associated with excessive axialrotation[2], the device might clinicallyimpact low back pain. Furtherdevelopment and testing of the AROdevice appears warranted.




428Management of Thoracolumbar FlexionDistraction InjuriesDavid Kung, Patrick W. HitchonIntroduction:Thoracolumbar flexion-distraction injuries result from disruptionof the posterior tension band and involveall three vertebral columns. Surgicaltreatment is often required for theseunstable injuries, partly because theassociated ligaments heal poorly, despitereduction and prolonged immobilization.Conservative management often resultsin kyphotic deformity. We present our 7-year experience with management ofthoracolumbar flexion-distractioninjuries.Methods:We reviewed our prospectivelycollected spine trauma database andidentified 23 cases of thoracolumbarflexion-distraction injuries from May2003 to August 2010. Demographic,clinical, radiographic and surgical datawere reviewed.Results:Twenty-three patients wereidentified. The mean age was 26 years.Male to Female ratio was 2:1. Seventeencases resulted from motor vehicleaccidents, five cases involved falls from aheight, and one from a skiing accident. Allpatients were recommended surgery, butone declined. Radiographically, allpatients had injury to the posteriorligamentous complex which includes thesupraspinous ligament, interspinousligament, ligamentum flavum, and facetjoint capsules. Levels of injury spannedT4 to L2. The most commonly injuredlevel was L1, followed by T12. With theexception of 2, all surgical patientsunderwent open reduction and posteriorinstrumentation. Three patientsunderwent short segmentinstrumentation, defined as less than twolevels above and two levels below theinjured level. Mean follow-up was 14months. Kyphotic angulation improvedby 5.5 degrees on average. Two patientsrequired revision for misplaced pediclescrews. One patient developed woundinfection that was treated conservatively.The patient who declined surgery haspersistent back pain and progression ofkyphosis from 8 degrees on initialadmission to 32 degrees at 5 monthfollow up.Conclusion:Our experience shows thatfor thoracolumbar flexion-distractioninjuries, a posterior approach withinstrumentation is sufficient to restorestability, correct deformity, anddecompress the neural elements.Percutaneous screw fixation my furthersimplify the surgical management of thisinjury.

429Complications and Oncologic OutcomesAfter Multilevel En Bloc Spondylectomy in11 PatientsMarcella Madera, Ilya Laufer, Ziya L. Gokaslan, Ali Bydon, Daniel M. Sciubba, Timothy F. Witham,Jean-Paul WolinskyIntroduction: En bloc spondylectomy hasemerged as a surgical treatment of spinalprimary and metastatic tumors whenoncologic resection is desired. Theseprocedures are technically demanding,and multilevel en bloc spondylectomyhas been reported in limited cases in theliterature. The purposes of this study areto explore the complications thatmultilevel spondylectomies incur, todetermine if level of resection affects rateof complications, and to explore the rateof local control that can be achieved withthis approach.Methods:We retrospectively reviewed allthe en bloc spondylectomies done at ourinstitution from 2004-present andevaluated the complications of allmultilevel cases.Results:Of 38 total en blocspondylectomies, 11 patients underwentmultilevel surgery (8 for primary and 3 formetastatic tumors). Distribution of caseswas as follows: 1 cervical (C2-4 resected),1 cervicothoracic (C7-T3), 4 thoracic (T1-3, T7-8, T6-7, T1-5), 1 thoracolumbar(T12-L2), and 4 lumbar (3 at L4-5 and 1 atL3-5). There was a 100% majorcomplication rate in the cervical,cervicothoracic, and lumbar cases. Therewere no complications in thethoracolumbar case, and the majorcomplication rate for thoracic cases was25%. No patients had recurrence at lastfollow-up (median 8 months, range 1-32months). There were no perioperativedeaths. 2 of the 3 patients with metastaticdisease died after last follow-up.Conclusion:Multilevel en blocspondylectomy has a high majorcomplication rate in the cervical andlumbar spine, but our results suggest thatthoracic resections may be less morbid.None of the multilevel spondylectomypatients in our series had recurrence atlast follow-up. Although our series issmall, it represents the largest series inthe literature for multilevel en blocspondylectomy focused on criticallyevaluating complications. This data willhelp surgeons make educated decisionswith patients; the risk of majorcomplications must be weighed with theoncologic result.

430Complications of Open vs. MinimallyInvasive Lumbar Spine DecompressionRichard G. Fessler, Patrick Shih, Timothy R. SmithIntroduction: Lumbar stenosis is adebilitating disease with significantmorbidity. Minimally invasive modalitieshave demonstrated efficacy in thetreatment of neurogenic claudication.Direct comparison, however, betweencomplication rates of these newertechniques with open surgical techniquesfor lumbar decompression are lacking.Methods:This single-institution studyexamined neurogenic claudicantsbetween August 2007 and June 2009. 26patients received open surgicaldecompression, and 23 patientsmicroendoscopic decompression.Baseline demographic characteristics,peri-operative morbidity and mortality,length of hospital stay, and finaldisposition following hospitalization wererecorded. Morbidity was divided intomajor and minor categories as defined bydegree of requisite intervention andadverse impact on hospital stay.Results: Average age, number of surgicallevels, and preoperative ASA scores weresimilar in each group (p>0.05). There wasa trend towards longer operative timeassociated with the minimally invasivesurgical group (meanopen=112.0 min,SDopen=50.0 min, meanMIS=141.7 min,SDMIS=56.0 min, p=0.056). Whencompared to the minimally invasivesurgery group, the open surgical grouphad higher average EBL(meanopen=139.81 ml, SDopen=133.9ml; meanMIS=61.9 ml, SDMIS=67.4 ml;p=0.027), and longer length of hospitalstay (meanopen=2.9 days, SDopen=2.0days; meanMIS=2.0 days, SDMIS=2.4days; p=0.004). There was a trend towardincreased utilization of ancillary supportafter discharge in the open surgery group(23% in the open group vs. 4% in the MISgroup, p=0.063).Conclusion:This study demonstrates thatminimally invasive decompression is atleast as safe as open decompression forlumbar stenosis. While MIS may beassociated with slightly longer operativetimes, there is decreased blood loss,shorter hospital stays, and likelydecreased requirements for ancillarysupport services upon discharge.




431The Use of the Mayfield Frame FacilitatesTrajectory in Anterior Odontoid ScrewFixationJonathan A. Grossberg, Heather Spader,Thomas W. Belknap, Adetokunbo A. OyeleseIntroduction:Type II odontoid fracturesmay be managed with haloimmobilization, posterior fusion, andanterior odontoid screw fixation. Whileanterior odontoid screw fixation hasshown excellent fusion results, screwplacement is difficult andcontraindicated in posteriorly displacedfractures and in barrel-chested patientsbecause of difficult screw trajectory. Wereport our experience using three-pointcranial fixation, with a Mayfieldheadframe to aid in alignment and screwplacement of complex fractures.Methods:Demographic and outcomedata were retrospectively collected in 19patients with type II odontoid fracturestreated with Mayfield assisted anteriorodontoid screw fixation. The Mayfieldframe allowed neck extension to reduceposteriorly displaced fractures and toachieve a favorable screw trajectory inbarrel-chested patients.Results:Mean patient age was 71.4(Range: 37-92); Six of the patients werefemale and eleven were male. Seven ofthe nineteen patients had fractures withradiographically measured posteriordisplacement of the fracture fragment ofgreater than 2 mm. The meandisplacement in these patients was 5.8mm (Range 3-8 mm). At least three of thepatients had barrel chests that wouldhave precluded anterior odontoid screwplacement without the Mayfield. Therewere no instances of hardwarecomplications on follow-up. Noprocedure was aborted because of poortrajectory or inability to reduce thefracture. There were no mortalities in thepopulation. Complications includedpneumonia (five patients), gastrostomytube placement due to patient failingswallow evaluation (six patients), andvocal cord paralysis (one patient).Conclusion:Utilization of a three-pointMayfield fixation frame allows theachievement of favorable screw trajectoryfor anterior odontoid screw placement inposteriorly displaced fractures and inbarrel-chested patients. It represents anovel modification of a well establishedprocedure that allows screw placement inheretofore difficult patients whileavoiding the morbidity and loss of rangeof motion from a posterior fusion in thispopulation.

432Effect of Post-Operatory Deep WoundInfection in Lumbar Arthrodesis on theLong-Term Outcome in Patients withDegenerative Disease: A Case-CohortStudyAsdrubal Falavigna, Orlando Righesso,Alisson Teles, Pedro Guaresi SilvaIntroduction:Deep wound infection isone of the most common and seriouscomplications in spine surgery. Theinfluence of this kind of complication onlong-term outcome for the patients is notwell established. The purpose of thisstudy is to evaluate the satisfaction andfunctional outcome in patients with deepwound infection after lumbar arthrodesisfor degenerative disease.Methods: A case cohort study with 13patients with clinical and radiologicaldiagnosis of lumbar spondylosis who thatpresented deep wound infection afterdecompression and instrumentedsurgical procedure between January of1997 and January of 2010. A 3:1 cohort(n=39) was selected for the comparisons,based in the following variables: gender,age and period of surgery. The patientswere treated with wound opening,collection of material for microbiologicalexamination, thorough washing,debridement of devitalized tissues,placement of continuous washingsystem, primary suture of the wound andintravenous antibiotic therapy followedby oral administration. In all cases theinstrumentation was maintained.Validated instruments were used toevaluate pain, numerical rating scale ofpain (NRS), disability, Oswestry DisabilityIndex (ODI), quality of life, short-form 36(SF36), anxiety and depression, Beckdepression scale (BDI) and HospitalAnxiety and depression scale (HADS) andpatient satisfaction.Results:The median patient follow-upwas 22 months (P25: 12 - P75: 32; min: 6 -max: 108). The mean age was of 61.74(±9.78) and 59.6% of the patients werefemale. There was no significantdifference in the evaluation of pain,functional disability, quality of life,depression and anxiety. However, 53.8%of the patients with infection wereconsidered dissatisfied with theprocedure on the final evaluation,compared with 15.4% of the patientswithout deep wound infection (p=0.001).Conclusion: Patients submitted tolumbar arthrodesis who that presentedpostoperative deep wound infection aremore likely to be dissatisfied with theprocedure than patients who did not

present wound infection in the long-termoutcome.

433The Finite Helical Screw Axis and theKinematic Response of the Lumbar SpineDunbar S. Alcindor, Daniel Cook,Jonathan B. Bellotte, Donald M. Whiting,Boyle C. ChengIntroduction: Spinal fixation for a myriadof vertebral and spinal injuries continuesto evolve and so too has the implants forspinal fixation. The appropriateimplant(s) to assist arthrodesis atdiseased levels and enhance lumbarspinal fixation in a timely and durablemanner is unclear. Finite helical screwaxis has been one of many parametersused to explain the kinematic response ofa spinal construct to loading. The aim ofthis study is to explain this concept inrelation to spinal fixation with both rigidand semi-rigid rods.Methods: Six lumbar cadavericspecimens were used. The specimenswere stripped of all soft tissue withosteoligamentous structures retained. Inaddition, the specimens were thoroughlyassessed for levels of degeneration andunderwent bone density scanning andCT imaging. Biomechanical testingincluding flexion and extension bending,axial compression lateral bending andtorsional testing. Treatments were carriedout from least invasive to most invasive.The intact spine was examined followingdiscectomy and implantation ofinterbody grafts; and spines with rigid orsemi-rigid rods along with interbodygrafts. The semi-rigid rod was tested inthree locations: midway between andagainst each superior and inferior pediclescrews. One-way repeated-measuresANOVA was used for statistical analysiswith p<0.05 considered significant.Results:The shift in the finite helical axiswith respect to the intact spine wasassessed. It is well known that rigidposterior fixation shifts the axisposteriorly, and this is not refuted by ourdata. However, no difference wasdetected in the way the axis was shiftedby the rigid and semi-rigid rods. Also, itdid not seem to matter how the rod waspositioned. There were no statisticallysignificant differences detected betweentreatment groups in any mode of loading.Conclusion:There were no differencesbetween treatment groups. Therefore,with respect to fused vertebrae, semi rigidrods and rigid rods showed no significantdifference when movement wasconsidered.




434Initial Discectomy May Affect AdjacentDisc Level Associated with Progress ofDegeneration and AgingAli Dalgic, Ali Yildirim, Onder Okay, Ergun Daglioglu, Ozhan Uckun, Osman Nacar, Cagatay Ozdol, Ersin Polat,Deniz BelenIntroduction: Failure of surgicaltreatment for lumbar disc herniation(LDH) can be commonly caused byrecurrence of LDH and new LDH at thedifferent level. There are many debatesregarding the risk factors of rLDH and it isvery difficult to define them becausemany clinical and complicatedbiomechanical parameters are involved.The purpose of study was to evaluate thelong term result of re-discectomy for LDHat the same level and adjacent segments.Methods: Between 1999 and 2009, overall1898 cases were operated on 142 (6.4%)patients underwent re-discectomyfollowing initially operation. The studyincluded 65 patients who were operatedon single level discectomy, and theircharts analyzed retrospectively.Results:There were 32 (50%) women andmean age was 45.5 years (range, 24 - 73years). rLDH was diagnosed at initial levelin 39 (60.9%), but adjacent and/oropposite level herniation (with or withoutthe first level) were founded in remaining25 cases (39.1%). Recurrence at samelevel (SLG) and adjacent level groups(ALG) were similar according to theclinical outcomes in follow-up meanly(34.1 months). Admission period afterinitial operation was also parallel SLG andALG (54.7 and 53.1 months, respectively)however mean age of ALG (49.4) wassignificantly higher (p=0.05) than SLG(42.8).Conclusion: As the pathologic changeshave been correlated with excessiveresection of bony structures and softtissue, responses to axial compression onintervertebral disc pressure caused todeformations of adjacent neural archesdespite of its appear to be limited.Eventually, the symptoms due toaccelerated degeneration can already befound after 2 years and collapsed discsare biomechanically more stable thanthose with preserved disc height.However, stable segment eliminatedmotion of the functional spinal segmentand may overload the adjacent segments.Finally, altered biomechanical loadingnext to a fusion resulted in ongoingdegeneration with aging at the affectingentire lumbar spine.

435Comparison of Navigated vs. Non-Navigated Pedicle Screw Placement:Screw Accuracy and Complexity ofSurgeryNeal Luther, Harry H. Gebhard, Tatianna Olivia Saleh, Juliano Fratezi,Apostolos Tsiouris, Roger HartlIntroduction: Pedicle screw fixation is aneffective method for achieving fusion inthe thoracic and lumbar spine. However,incorrectly positioned screws whichsignificantly breach the pedicle can causespinal cord, nerve root, or vascular injury,as well as dural tears and CSF leaks. Thesepotential risks are heightened in caseswhere other factors increase complexity,such as previous surgery which maydistort anatomy, or the presence ofdeformity. Computer 3D navigation (3DNAV) techniques in spinalinstrumentation can theoreticallyimprove screw placement accuracy andreduce potential injury to criticalneurovascular structures.Methods:We retrospectively analyzed theaccuracy of 3D NAV in pedicle screwplacement for 109 patients (526 screws)in comparison to screws placed withconventional lateral fluoroscopy in 84patients (600 screws) on postoperative CTscans using a four-point scale (0-3).Complex cases were deemed as thosewith significant deformity, previoussurgery, or a minimally-invasiveapproach. We evaluated whether specificpreoperative surgical criteria with regardsto complexity influenced the use of 3DNAV.Results: Screw accuracy overall wascompared statistically between the 3DNAV and the lateral fluoroscopy group byFisher’s exact test. The number of grade 0vs. grade 1 and higher (i.e. breachedscrews) in both groups were compared.No significant difference was seenbetween groups (p=0.08). The use of 3DNAV strongly correlated with casecomplexity, as 92% were designated ascomplex, whereas 79% of the fluoroscopycases were complex (p<0.05).Conclusion:The use of 3D NAV results inhighly accurate screw placement whencompared to standard fluoroscopicguidance, and may be of particular utilityin cases of higher degrees of complexity.

436Effect of a Novel Annular Repair Device(Barricaid) on Same Level Recurrent DiscHerniation and Disc Height Loss AfterPrimary Lumbar Discectomy: Results of aMulticenter Non-randomized ProspectiveCohort StudyScott Parker, Kaisorn L. Chaichana, Darko Ledic, Milorad Vilendecic, Matthew J. McGirtIntroduction: A subset of patients willexperience same-level recurrent discherniation and disc height loss anddegeneration after lumbar discectomy.Techniques to reduce theseconsequences may improve outcomesafter lumbar discectomy. In a prospective,non-randomized, comparison cohortstudy, we set out to evaluate if an annularrepair device could be implanted safely,reduce same-level recurrent discherniation, or attenuate disc height afterlumbar discectomy.Methods: Fifty-four patients undergoinglumbar discectomy for a single-levelherniated disc at two institutions wereprospectively followed with clinical andradiographic evaluations every threemonths for one year after surgery (controlcohort). Subsequently, a secondconsecutive cohort of 30 patientsundergoing 31 lumbar discectomies withimplantation of an annular repair device(Barricaid) was followed for 12 months.Incidence of recurrent disc herniation,percent disc height loss, and leg and backpain visual analogue scale (VAS),Oswestry Disability Index (ODI), andquality of life (SF-36) were comparedbetween cohorts.Results:Cohorts were similar in regardsto age, weight, preoperative disc height,and level of disc herniation, Table1.Recurrent same-level disc herniationoccurred in 5 (9.2%) patients in thecontrol cohort vs. 0 (0%) patients in theannular repair cohort (p=0.08). Meanone-year percent disc height loss was26.4% in the control cohort vs. 13.8% inthe annular repair cohort (p<0.01), Figure 1. Patients in both cohortsexperienced significant (p<0.01)improvement in back and leg pain VAS,ODI, and SF-36, Figure 3. Twelve monthsafter discectomy, patients in the annularrepair cohort experienced less leg paincompared to the control cohort (VAS: 0.6 vs. 1.6, p<0.05), Figure 2.Conclusion: Implantation of a novelannular repair device was performedwithout any device related morbidity andwas associated with a reduction inpostoperative disc height loss, a trend of




reduced recurrent disc herniation, andimproved one-year leg pain.

437Digital Protractor as a Supplement toThoracic and Lumbar Pedicle ScrewPlacement: A Cadaveric StudyMaureen A. Darwal, Bradley T. Bagan,Mirza N. Baig, Robert A. Hirschl, Chris S. KarasIntroduction:The objective of this studyis to test the ability of a novel device toassist in the insertion of pedicle screwswith respect to the medial-lateral angle.Methods: A digital protractor was addedto the handle of a surgical multi-axialscrewdriver. The device was zeroed at aplane parallel to the spinous process atthe anatomic entry point, and thenmoved laterally to an angle alreadydefined in a previous anatomical study byZindrick et al. (2000), which correspondsto the medial angulation of the pedicle.Screws were inserted by the device at thespecified angle. The procedure wasperformed at levels T1-L5 with theaddition of lateral fluoroscopy in thelumbar spine to define the superior-inferior angle. Medial-lateral angles ofeach screw were confirmed onpostoperative CT scan. Successful screwplacement was defined as standardpedicle purchase or purchase parallel tothe pedicle in the medial-lateral plane.Results: At all levels the screws purchasedthe pedicle entirely or were implantedwith partial purchase and with an angleparallel to the pedicle. All screws weresuccessfully angulated in the medial-lateral plane using the novel device,including those placed by individualswith no previous spinal instrumentationexperience.Conclusion:The addition of a digitalprotractor to current spineinstrumentation is a useful adjunct to theaccurate placement of thoracic andlumbar pedicle screws. Further studiesmust be done to more precisely definethe proper entry point when consideringthe supplementation of pedicle screwplacement with digital protraction.

438Avoid Failed Back Surgery Syndrome Dueto Lumbo-sacral Epidura1 FibrosisIñaki ArroteguiIntroduction:The objective of thisProspective, Randomized Controlled Trialwas to investigate the potential benefitsof using the Collagen Dural Matrix as anadhesion barrier following spine surgeryin order to avoid periradicular lumbarfibrosis.

Methods: 2006-2008 (DuraGen Plus 200cases 2-years follow-up) was conductedby the investigator at a single siteOUTCOME MEASURES: Clinical follow-up: 2 years, 1 month, 6 months, 1- 2 yearsGadolium IRM (if complain of pain).Postoperative Pain Assessment at eachtime point: 2 = No Pain, 3 = Mild Pain, 4 =Moderate Pain, 5 = Severe Pain. VASquestionaire Extent of Fibrosis graded byGad-MRI: Control Group 100 standrprocedure (Discectomy) 2006 MatrixGroup 200 standr+ matrix (2006). Clinicalfollow-up+stadistical tests+vasquestionaireResults: Results from the DuraGen GroupPostsurgical fibrosis was found in 1.8% vs.6% S group. Pain Outcomes: Results fromthe Control Group (Standard Practice).Patients with more fibrosis, shown by thearrows, exhibited more significantsymptoms. Mean post operative painscores for the DuraGen Group were lowerat all time points and statistically lower at3 to 6 months. The difference in re-operation rate between the collagenmatrix group and the standard proceduregroup is statistically significant (p<0.001).Conclusion:The use of DuraGen plusresulted in statistically significant surgicaloutcomes 1.8 % vs 6 % None of the 100patients from the collagen Grouprequired re-operation due to clinicalsymptoms.

439Collagen Dural Matrix Used To AvoidComplications In Carpal Tunnel ReleaseIñaki ArroteguiIntroduction: A thorough knowledge ofthe anatomy of the carpal tunnel isessential in order to avoid complicationand to ensure optimal patient outcome.There are many strong arguments foropen (Short Incision 2.5 cm) vs.conservative treatment.Methods:The study cohort (collagenmatrix group) consisted of consecutivepatients (250 patients) who were treatedwith collagen Dural matrix. Patients inthe standard procedure group (250patients in all) were operated on prior tothe adoption of matrix use by thesurgeon. OUTCOME MEASURES:Patients underwent carpal tunnel surgerysame technique in both groups andcompleted follow-up evaluations at noless than 12-months post-operation.Clinical symptons EMG studies, VASquestionaire Methods: All patientscomplained of numbness and/or sensoryor weakness disturbance in the mediannerve distribution of the hand. Tinel andphalen sign tests were positive in

approximately two-thirds of the patients.EMG studies were performed in allpatients and were positive between mildto severe.Results:Numbness and paresthesiaswere relieved in 89% DG group and 86%in Control Group; pain was relieved in89% DG and 86% CG. Motoric Wekneswas relieved in 95% DG and 92 % CG.Normal grip strength was found in 93%DG and 91% had normal pinch strength.Control group: Adhesion of the flexortendons in 3 patients. 5 patients hadscarring of the median nerve. DuraGengroup: Recurrent pain: 1 patients forincomplete division of transverse carpalligament The difference in re-oprationrate between the collagen matrix groupand the standard procedure group isstatiscally significant (P<0.01).Conclusion: Findings in this study(reduced pain and lower incidence ofadhesions) are consistent with theCollagen Dural Matrix acting as aneffective adhesion barrier.

440Minimally Invasive Lumbar Fusion (XLIF)Using a ² TCP-HA Bone Graft Substitute(FormaGraft): Fusion Rates Out to 2 YearsW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:Good short-term outcomespost-XLIF have been shown. Fusionoutcomes have been assumed to meet orexceed those of other interbody fusionprocedures due to access for greater diskpreparation, large structural implant, andretention of stabilizing ligaments. Noreports to date focused on fusion ratesassociated with XLIF, or on the graftmaterials used in XLIF. Given thelimitations of autograft, many surgeonsuse bone morphogenic protein in lumbarfusions. However, early resorption andhospital cost have fueled consideration ofother bone graft substitutes.Methods:The use of a beta-tricalciumphosphate/hydroxyapatite (FormaGraft)with bone marrow aspirate (BMA) wasprospectively studied in 57 consecutive 1-and 2-level XLIF procedures.Radiographic outcomes were evaluatedto demonstrate fusion and werecompared with clinical results.Results: Patient age ranged 25-79 years(ave55.9yrs). Primary diagnoses includedstenosis (31), DDD (12), spondylolisthesis(8), and HNP (6). Comorbid conditionsincluded previous spine surgery (47.4%);smokers (40.35%); diabetes (22.81%);chronic steroid use (8.77%);obesity/morbid obesity (52.6%). 64 levelswere treated: 50=1-level, 7=2-level; 1 at




T8-9, 4 at L1-2, 6 at L2-3, 16 at L3-4, 37 atL4-5. Graft included equal amounts byvolume FormaGraft and BMA, aspiratedfrom adjacent vertebral body (lateralexposure). All included supplementalfixation. Hgb change and hospital stayaveraged 1.20g and 1.04 days.Complications included one iatrogenicHNP requiring secondarydecompression. One patient died at 10months post-op, unrelated to his surgery.Average disk height improved from6.35mm to 10.86mm, maintained at10.0mm at 24 months. Fusion by Lenkescore=1 and 2 was 90.0% at 24 months.Average VAS pain scores decreased from9.0 pre-op to 3.2 and 3.6 at 12 and 24months. 89% expressed satisfaction at 12months, and 89% said they would do itagain.Conclusion: XLIF has proven to be a safe,effective procedure, and now 24-monthresults using ßTCP-HA bone graftsubstitute confirm fusion, maintenanceof improvements, and overall patientsatisfaction.

441PLIF: Implications for the Post-opRadiological Examination and QoLNikolaos Syrmos, Mario Ganau, Cristian Gragnianiello, Dimitrios ArvanitakisIntroduction:The aim of this study is toevaluate the clinical and radiologicalresults after PLIF surgery for lumbarDegenerative Disc Disease (DDD) andinstability in a consecutive series of 24patients.Methods: By using appropriate clinicalscales (VAS, JOA and SF-36) and repeatedradiological exams (plain X-rays and CTscans) the following parameters havebeen reviewed: clinical satisfaction,quality of life (QoL), cage size, segmentallordosis and pre/post-op ratio of theintersomatic distance.Results:VAS score decreased significantlyafter surgery, as well a remarkableincrease in the JOA score was noticed inall patients, even in cases of low pre-opvalues. The SF-36 test confirmed goodresults in terms of QoL. Radiologicalanalyses of cage size, segmental lordosisand pre/post-op ratio of the intersomaticdistance allowed for a quantitativeevaluation of surgical Results: goodcorrection of spinal instability andincrease in disc height was alwaysachieved despite a slight reduction inlumbar lordosis. No cases of cagedislocation were noticed during thefollow up (up to 36 months).Conclusion: It seems that expandable

cages give more advantages in terms ofprevention of rotation and retropulsionafter interbody placement, neverthelessno data actually support this hypothesis.Clinical results are also positive regardingthe QoL, even despite the poorest pre-opconditions.

442Dynamic Spinal Fusion Constructs andthe Range of Motion of the FunctionalSpinal UnitAbraham E. Sabersky, Daniel Cook,Jonathan B. Bellotte, Donald M. Whiting,Boyle C. ChengIntroduction:There has been an increasein interest in the use of dynamic spinalfusion systems. Dynamic fusion devicesprovide stabilization through immediatefixation while allowing load sharingwhich, theoretically, should facilitate thebone healing process. A biomechanicalstudy was designed to characterize therange of motion (ROM) of the functionalspinal unit (FSU) in its native form, with arigid rod construct, and a dynamic fusionconstruct with the dampener in threedifferent positions.Methods: Six fresh-frozen spines wherecleaned of muscle and soft tissue andtested for range of motion. Thebiomechanical testing employed astandard flexibility protocol withindependent motors driven in loadcontrol for bending modes of loading.Each specimen was subjected to fourmodes of testing for each treatmentincluding 1) axial compression, 2)flexion/extension, and 3) lateral bending.The three dimensional kinematicresponse between each of the vertebralbodies was measured through acalibrated optical tracking unit. The ROMwas measured as a displacementresponse in a given plane for each modeof loading with a repeated measure oneway ANOVA to test for differencesbetween the means of each treatmentgroup.Results: ROM of the index level was takenfrom the 3rd cycle of each test protocol.The scalar value of the angular ortranslational change during the 3rd cyclewas reported for each specimen. Themean from all specimens for eachtreatment was calculated and reportedalong with the standard deviation. Astatistically significant difference wasdetected between the native specimensand all treatment groups but nosignificant difference was detectedbetween the treatment groups in anymode of loading.Conclusion:The dynamic spinal fusion

construct allows stabilization comparableto that of a rigid rod. In the postoperativeperiod, the device serves to provide alarge portion of the immediatestabilization and fixation at the indexlevel. This design attribute requiresfurther validation in the clinical setting inorder to gauge the appropriate responseso that significance can be predicted.

443Characterization of Articulation of theLumbar Facets in the Human CadavericSpine Using a Facet-Based CoordinateSystemMithulan Jegapragasan, Daniel Cook,Dave Gladowski, Adam S. Kanter, Boyle C. ChengIntroduction:The three-joint-complex,which includes the two facet joints andthe intervertebral disc, significantlydirects the movement of the lumbarspine. When studying the biomechanicsof this complex, kinematics havetraditionally been measured relative to avertebrae-based reference frame.Recently, a facet-based reference systemhas been used to describe the samemotions, but relative to the facets.Methods: Seven fresh-frozen,noninstrutmented human cadavericlumbar spines from L1 sacrum weretested in flexion extension, axial rotationand lateral bending. Three coordinatesystems were assigned to each vertebraefrom L1-L5: one corresponding to thevertebrae reference frame (X, Y, Z) andtwo corresponding to the left and rightfacet reference frames (A, B, C). The facet-based reference frame was aligned toeach facet surface to provide descriptionsof in plane (articulation) and out of plane(separation) motion. For each of the threemodes of loading, the magnitude of thetranslational range of motion vector wascalculated for the three reference frames.Results:During flexion extension, therewas a significant difference in themagnitude of the translational range ofmotion vector of the right facet ascompared to the vertebrae at L1-L2.During axial rotation, there was asignificant difference between themagnitude of the translational range ofmotion vector at L2-L3, L3-L4, and L4-L5.L1-L2 trended towards significance.During lateral bending, there was asignificant difference in the magnitude ofthe translational range of motion vectorat L1-L2, L2-L3, L3-L4, and L4-L5.Conclusion: A facet-based referenceframe accounts for variations in facetorientation and provides a valuablecharacterization of facet articulation and




separation that is not possible to derivefrom translations in a vertebrae-basedreference frame.

444Use of Three-Dimensional ComputedTomography and Image Guidance DuringOccipital Condyle Screw Placement and Occipitocervical Instrumentation: A Technical NoteClinton Judson Burkett, Tien V. Le, Edwin Ramos, Fernando L. Vale, Juan S. UribeIntroduction:The use of occipitalcondyle screws for occipitocervicalfixation has been described as a safereproducible technique in both cadavericand clinical reports. Avoidance of criticalstructures of the complex craniocerivicaljunction during placement of thesescrews is of vital importance. Visualizingthe placement of condyle screws usingfluoroscopic XRay can be difficult.Intraoperative 3D CT imaging and imageguidance allows for acquisition andimmediate interpretation of multi-planarthree dimensional images. Intraoperativeimage guidance can be applied to theplacement of occipital condyle screws forincreasing the accuracy, reproducibility,and safety of the procedure.Methods:The authors describe atechnique for placing occipital condylescrews in conjunction with C1 and C2screws using 3D image guidance. Thistechnique has been used in four patientsto date. Intraoperative 3D CT imaging (O-Arm) and image guidance (Stealth StationS7 & Treon) were used in this study. Imageguidance was used for localizing, drilling,tapping, and placement of occipitalcondyle, C1 lateral mass, and C2 parsscrews in all four patients. The 3D CTscan was performed in the operatingroom in two patients for image guidanceand checking screw trajectories beforeclosure.Results:No complications resulted fromthe use of image guidance or with theplacement of occipital condyle, C1 lateralmass, and C2 pars screws. In two patients,3D CT scan after placement of all screwsensured proper placement of all screwsbefore leaving the operating room.Conclusion: Placement of occipitalcondyle screws with 3D CT imaging andimage guidance is safe and effective. Asecond 3D CT scan done after placementof screws is useful to guarantee adequatescrew trajectories, which may prevent anunplanned return to the operating room.

445A Clinical Evaluation of Two-Level LumbarFusion Using a Combination of theAxiaLIF and XLIFW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:The peri- andpostoperative complications associatedwith the XLIF and AxiaLIF procedures arereported to demonstrate the feasibility,safety, and effectiveness of theapproaches when used in combination.In our single-site consecutive series of190 AxiaLIF patients, 32 had two levelfusions with a combination of the AxiaLIF(L5-S1) and XLIF (L4-L5) techniques.Methods: Peri- and postoperativecomplications and their relation toclinical and radiographic outcomes wereevaluated, in addition to surgical details,hospital stay, VAS scores, disc heights, andreoperation rate. Thirty-two patients witha mean age of 55.4 years and a mean BMIof 30.9 received two-level fusions with anAxiaLIF at L5-S1 and XLIF at L4-L5 . TheVAS scores, disc heights, and radiographicevaluations are presented at 3, 6, 12 and24 months postoperatively separated bylevel.Results:The mean VAS score in thesepatients preoperatively was 8.9 anddemonstrating a 5.1 point drop (57% reduction) in the VAS score. OR timeaveraged 137 minutes. There were notransfusions or infections. One patientrequired a laminectomy at 4 weeks andanother an XLIF at 24 months. There wereconsistent differences in radiographicparameters between the XLIF andAxiaLIF levels at 12 months: Lenke scoresat L45 averaged 1.16 and 2.22 at L5S;while the L45 levels lost 0.8 mm in diskheight over 12 months, the L5S1 levelslost 2.15 mm.Conclusion:Multilevel fusion at thelumbosacral junction can be achievedusing a combination of XLIF and AxiaLIFprocedures. While the associatedcomplications markedly less thantraditional open techniques, fusion wasinfrequently demonstrated at the L5-S1level even at 24 months.

446Are MIS Spinal Fusion OutcomesPredictable? Factors of StatisticallySignificant Outcomes Predictability inMinimally Invasive Spinal FusionsW.B. Rodgers, Edward J. Gerber, Jody A. RodgersIntroduction:Herein, we assess if MISfusion success or reoperation can bepredicted based on demographic and

outcome factors.Methods:Clinical and radiographicoutcomes from our series of 941 XLIFswere prospectively recorded. Factors wereanalyzed to determine the statisticalsignificance of effect on success, definedas improvement of at least two points onthe VAS-pain-scale. Outcome measuresincluded the results of statistical analysistesting the effect of demographiccharacteristics and outcome factors onsuccess (VAS decrease of at least 2pts) orthe occurrence of reoperation. Statisticalsignificance defined as p<0.05.Results: Preop VAS was a factor in 12mosVAS success. (p=0.0283). At 24 months,preop VAS approached significance(p=0.0548). Age was a significant factor insuccess at 12 months (p=0.0283); patientsachieving success were on average, older.Patients with COPD were less likely tohave success at 24 months (p=0.0114).Smoking trended towards significance at12 months (p=0.0502) but was not afactor at 24 months. Other aspects foundnot to be significant factors in 12 or 24months outcomes: occurrence ofcomplications or reoperations, priorfusions, and comorbidities (CAD,diabetes, steroid use, and cancer). Loss ofdisc height at 6 months postop was astatistically significant predictor ofreoperation for residual symptoms.Specifically, greater than 5mm lost frompostop to 6 months, or a loss of >50% ofsurgically gained disc height, is predictiveof reoperation (p=<0.0001). Patients wholose <1mm (or <10% disc height) frompostop to 6 months require significantlyless reoperations (p=0.0034).Conclusion:The ability to predict long-term MIS fusion outcomes may haveconsiderable impact. Results of the ageanalysis are significant for relief of pain inthe elderly, a challenging group to treat.Also of importance is potential to preventreoperation. Technique, implant size, andposterior fixation method may also befactors.

447Minimally Invasive Treatment ofThoracolumbar Spine FracturesJacinto Manon, Cara Sedney, Brenton R. Coger, James Mills, Terrence D. JulienIntroduction:ThoracoLumbar spinalinjuries are common, especially in blunttrauma such as motor vehicle accidentsand falls. These injuries often necessitateoperative interventions to restore stabilityto the spinal column. While moretraditional methods of spinal fusion aresuccessful for these injuries, newer




minimally invasive techniques have beendeveloped and show promise in thesetting of traumatic injury.Methods: All surgical cases from thesenior author over a period of 30 monthswere reviewed. Cases of minimallyinvasive fusions done for thoracolumbartrauma were identified. Laminectomiesand kyphoplasty/vertebroplasty wereincluded. These cases were assessed foroperative time, length of hospital stay,and estimated blood loss. The exactprocedure and number of levels fusedwere also recorded.Results:Of the 95 minimally invasivecases performed over a 30 month periodby the senior author, 30 of these wereminimally invasive fusions forthoracolumbar spinal trauma. Theaverage number of levels fused was 5.Average estimated blood loss was 254 ml.Average operative time was 3 hours and40 minutes. Average hospital stay was 8.9days.Conclusion:Minimally invasive spinalfusion techniques are promising andgrowing in popularity. Minimally invasivetechniques in general have been shownto reduce length of stay, postoperativepain, and blood loss. There may be aparticular utility for minimally invasivetechniques in spinal trauma for thesesame reasons. A direct comparison ofminimally invasive techniques with moretraditional methods of spinal fusion fortrauma is warranted to assess thesetopics.

448The Treatment of Thoracolumbar BurstFractures by Using Short SegmentTranspedicular Screw InstrumentationUlas Yener, Deniz Konya, Gulden DemirciIntroduction:One of the major problemsin the surgical treatment ofthoracolumbar burst fractures is tomaintain enough support to the anteriorcolumn. In this research we present theassestment of thoracolumbar burstfracture patients clinically andradiologically who had been treated withshort segment transpedicular screwinstrumentation.Methods: 21 cases (12 male, 9 female)were retrospectively reviewed who hadthoracolumbar burst fractures andtreated with short segmenttranspedicular screw instrumentation.Mean age was 53 (range 26 - 78). Meanfollow-up period was 13.7 (range 3 - 28)months. The most common fracture levelwas at L1 vertebra (10 cases) and T12vertebra (4 cases), L3 vertebra (3 cases),L2 vertebra (1 case). Vertebroplasty had

been also administered to 15 cases tosupport the anterior column. In 10 casesat the level of collapsed vertebra we usedshorter transpedicular screws.Results: All cases were totally recovered attheir last controls. Their mean VAS scorein the preoperative period was 8.3 and 3.7at the 3rd month control ( p<0.05 ). MeanSDI score was 72.5 in the preoperativeperiod and 36 in the post operativeperiod. After the surgery no patient hadany additional neurological deficit.Conclusion:The use of short segmenttranspedicular screw instrumentation inthe treatment of thoracolumbar burstfractures less mobile segments are fusedtogether, posterior stabilization isenhanced at the level of fracture and insuitable cases by adding vertebroplasty tothe treatment proper anterior columnsupport is achieved. For these reasonsfixation with short segment traspedicularscrew instrumentation is a safetreaatment choise for thracolumbar burstfractures.

449Fractures of the Thoracolumbar Spine: A 33-year Review from the GeneralHospital Heraklion in CreteNikolaos Syrmos, Mario Ganau, Antonella De Carlo, Dimitrios ArvanitakisIntroduction:Thoracolumbar fracturescan be a disabling condition that requiresrapid and focused evaluation onadmission to the Emergency Departmentand a thorough treatment to avoidcatastrophic and neurologicallythreatening injuries. The spectrum ofinjuries is broad and includes: fractures,bony and/or ligamentous instability andneurologic compromise.Methods:Clinical data from a 1978-2009timeframe were retrieved from theGeneral Hospital Heraklion’s archives: atotal of 120 patients (mean age 39y; 86.6%men and 13.4% women) were admittedfor thoracolumbar spine fractures.Results:Most common mechanism ofinjury were: accidental falls 58.4% and caraccidents 24.1%. In 79.1% of recordspatients presented multiple traumas.Instability fractures accounted for 52.5%;neurological impairment for 25.8%. Aconservative treatment was choosen inmore than half of the cases. Only 43.4% ofpatients were operated: a good outcomewas demonstrated in 76.9% with partialor complete regression of neurologicaldeficits. Rate of instrumentation was 68%and rate of revision surgery was 7%.Conclusion: Spinal trauma is classifiedaccording to the mechanism of injuryand the presence or absence of spine

stability. A variety of imaging modalitiesincluding radiography, conventionaltomography, computed tomography, andmagnetic resonance imaging haveimproved along the years the assessmentof spinal injuries. Revising our data wecan state that: nonoperative treatmentwas successful in most of those injuries,whereas surgery was choosen in selectedcases of structural instability orneurologic compromise. Timing ofsurgery did not change along the years,and neurological compromise alwaysprompted an immediate surgicaldecompression.

450Observations on Bone MorphogeneticProtein in Transforaminal LumbarInterbody FusionsLuis M. Tumialan, Mark P. Garrett, Udaya K. Kakarla, Nicholas TheodoreIntroduction: Ectopic bone formation,radiculopathy, seroma development andosteolysis have been identified in TLIF’swith rhBMP-2. ALIF’s with rhBMP-2 inlumbar tapered cages, however, have notexhibited the same pattern ofcomplications.Methods: A retrospective review ofclinical and radiographic data wasperformed on all patients over a three-year period who had undergone lumbarinterbody fusion through either atransforaminal or anterior approach withrh-BMP-2.Results:Delayed radiculopathy, ectopicbone formation and osteolysis were allidentified within the TLIF group. Adelayed radiculopathy after atransforaminal lumbar interbody fusionappears to be the result of aninflammatory response of rh-BMP-2interacting with the exposed cancellousbone from the facetectomy. The area ofhyperintensity on T2 weighted MRimaging obtained 9-12 weekspostoperatively is highly predictive ofwhere bone deposition will occur. Boneformation has a tendency to form outsidethe collagen sponge and in the presenceof the rh-BMP-2 solution that is incontact with the cancellous bone fromthe violations of the endplate or thefacectectomy. Violation of the corticalendplate and exposure of the cancellousbone appears to be the cause ofosteolysis. None of these complicationswere identified in those patients whounderwent an ALIF with the same orgreater amount of rh-BMP-2.Conclusion: A lower dose of rh-BMP-2,eliminating the exposure of rh-BMP-2solution to the neural elements and




limiting the rh-BMP-2 enhanced spongeto an interbody device to avoid itscompression, collectively minimizes therisk of delayed complications from use ofthis protein.

451The Hybrid Interspinous Implant andFusion System in the Multilevel LumbarSpinal StenosisInsoo KimIntroduction: Patients with multilevellumbar spinal stenosis resistant toconservative therapy are typically treatedwith either fusion or non-fusion surgicaltechniques. Unfortunately, spinal fusionalters the normal biomechanics of thespine, and the loss of motion at the fusedlevel is compensated by increased motionand load at the other unfused segments.Possibly as a result of alteredbiomechanics at the adjacent mobilesegments, adjacent-segment disease(ASD), a serious complication of PLIF, canoccur. To reduce the incidence of ASD,the two techniques can be applied atadjacent levels using interspinousimplants in a segment-by-segmenttreatment of multiple level spinalstenosis. The objective of this study wasto evaluate the clinical and radiologicaloutcome of patients treated with hybridapplication of device for intervertebralassisted motion in one adjacent level as anon-fusion device and in other segmentsin combination with a posterior lumbarinterbody fusion (PLIF) as a fusion device.Methods: A retrospective review wasperformed in all patients who underwentposterior lumbar instrumentation of thehybrid interspinous implant withunilateral laminotomy bilateraldecompression and PLIF fusion system.The follow-up period ranged from 22 to39 months. Clinical outcome wasevaluated by Oswestry disability index(ODI), back- and leg-pain scores (VAS).Fusion success and system failure wereassessed by CT, AP and lateral X-rays.Results: A total of 15 consecutive patientsunderwent lumbar fusion surgery inwhich the hybrid system was used. Backpain (VAS) was improved from 6.9 to 3.2(p<0.05), leg pain (VAS) was from 8.1 to2.3(p<0.05), and ODI was from 53.6 % to27.3 % (p<0.05). There was no majorcomplication and system failure.Conclusion: A combination of interbodyfusion and non-fusion interspinousimplant treatments is technically feasible,safe, and effective for the surgicaltreatment of multilevel lumbar spinalstenosis.

452Radiographic Evaluation of InterbodyHeight Following Minimally Invasive L5-S1 Trans-sacral Axial FusionZachary Adam Smith, Budong Chen,Samantha Hemingway, Larry T. KhooIntroduction: Pre-sacral minimallyinvasive spinal (MIS) L5-S1 fusioncontinues to emerge as an importanttreatment for disease of the lumbosacralspine. Disk height (DH) loss anddistraction are important radiographicoutcomes, and the authors present initialradiographic findings and discuss theirimplications in 26 patients.Methods: Between June 2005 and January2009, 26 patients were treated with MISL5-S1 pre-sacral interbody fusion. Therewere 12 females and 14 males, with anaverage age of 48.7 years. The authorsconsidered these radiographicparameters: anterior and posterior discheight (ADH, PDH) relative to endplate(%, Farfan method), percentage increaseor decrease of ADH or PDH followingoperation; DH relative to implant (%,modified Farfan) at follow-up. Predictorsof DH loss are reported and analyzed.Results:Using a fixed end-plate length(Farfan method), average ADHdistraction was 46.7% (range 26.9-144.0)and PDH distraction 4.1% (-30.0-69.4) ineleven patients. The increase in ADH wassignificant (p = 0.05, student’s t test).Inter-rater reliability was .95. DH loss of15.9% (2.4-31.9) was observed in 22patients at 7.44 months (range 2-11months). In 16 patients with pediclefixation, DH was 9.9% (range 2.6-17.9). In8 with transfacet fixation, DH loss was20.9% (12.6-31.9%), (p <0.001). Smokinghistory, age, time, and degree ofdistraction did not predict disk heightloss. Weight > 250 lbs was predictive withmultiplicative analysis (p = 0.04). Inter-rater reliability was .87.Conclusion:MIS pre-sacral fusionprovides significant distraction of theanterior disk space. DH loss with time issimilar to established approaches forinterbody fusion. Preservation ofpostoperative DH may best preservedwith pedicle screw fixation.

453L5 Vertebrectomy for the SurgicalTreatment of Tumoral and TraumaticLesions of L5 VertebraeTuncay Kaner, Tunc Oktenoglu, Mehdi Sasani, Ali Fahir OzerIntroduction: L5 vertebrectomyperformed for rarely observed L5vertebral lesions in the lumbosacral

junction of the spine entails certainsurgical difficulties. We retrospectivelyreviewed the clinical characteristics andsurgical results of our seven patients whowere treated with L5 vertebrectomy.Methods: Pathologies, clinicalcharacteristics, preoperative andpostoperative radiological findings,surgical techniques, and instrumentationthat were used on seven L5vertebrectomy patients between 1998and 2008 were reviewed in their entirety.Operations were planned afterperforming biopsies in tumoral cases inthe preoperative period. Patients werechecked at three-month intervals in thefirst year, six-month intervals in thesecond year and thereafter on a regularbasis.Results:The mean follow-up period was46.3 months (ranging from 12 to 128months). One patient had a traumatic L5burst fracture, and the other six patientshad tumoral pathologies in L5 vertebrae.All patients were treated with anterior L5vertebrectomy, and anteriorreconstruction and posterior rigidstabilization were performed. None of thepatients developed any perioperativecomplications. Revision surgery was notperformed on any patients. Recurrencewas observed in the patient with thechordoma in the second postoperativeyear. This patient received radiotherapyafter the recurrence, a reoperation wasnot performed and patient exitus wasobserved in the third postoperative year.Conclusion: Although L5 vertebrectomyis a difficult surgery to perform, providingappropriate patient selection it can bepreferred in tumoral and traumaticlesions of L5 vertebrae as a surgicaloption. The lumbo-sacral region presentssignificant stabilization problems for thesurgeon. In order to provide stabilization,L5 vertebrectomy initiation should beaccompanied by anterior and posteriorrigid stabilization.

454En Bloc Hemisacrectomy and InternalHemipelvectomy Done from the PosteriorApproach: A Report of Two CasesMichelle J. Clarke, Hormuzdiyar H. Dasenbrock, Wesley Hsu,Ian Suk, Daniel M. Sciubba, Timothy F. Witham, Ali Bydon, Ziya L. Gokaslan, Jean-Paul WolinskyIntroduction: En bloc resection ofprimary tumors has a demonstratedlong-term disease-free survival benefitover palliative intralesional resections. Inpatients with pelvic tumors, traditionalsurgical treatment was the radical




hemipelvectomy or “hindquarteramputation”. More recently, limb-sparinginternal hemipelvectomy through alateral approach has been used. While aportion of the sacrum may be resected, inpatients with disruption of S1, thistrajectory will not allow appropriatelumbopelvic fixation. Previously, aposterior only approach to totalsacrectomy has been described, whichallows en bloc resection of the sacrumbelow the L5-S1 disc space andlumbopelvic fixation in a single stagethrough a midline incision. By extendingthe dissection laterally, we have been ableto perform an internal hemipelvectomyand hemisacrectomy in a singleprocedure, operating the patient in thesupine position.Methods:We present two cases ofsacroiliac tumors successfully treated by aposterior-only hemisecreactomy andinternal hemipelvectomy withsubsequent reconstruction.Results:The surcial procedure for an enbloc hemisacrectomy and internalhemipelvectomy is described. The firstsurgical priority is en bloc tumorresection with negative margins. Thesecond priority is skeletal stabilization:maintaining pelvic ring and lumbosacralcontinuity to stabilize the pelvic girdleand transfer weight-bearing forces fromthe axial to appendicular skeleton, whichallows locomotion and posture.Conclusion: A posterior approach tohemisacrectomy and internalhemipelvectomy is possible in theappropriate patient. This approach allowsexcellent bilateral stabilization of thelumbosacral juntion and decreasessurgical morbidity while allowing thesurgeon to achieve an en bloc resection.However, surgeons must be comfortablewith the posterior approach asretroperitoneal access is eliminated.Additonally, the limits of lateral accessmay preclude complete pelvic-femoralreconstruction if required.

455The Evaluation of IntraoperativeComputed Tomography with NavigationSystem in Lumbar Spine Trans-pedicleScrew (TPS) ApplicationJen-Tsung Yang, Ming-Hsueh Lee, Chu-Hsiang Chu, Martin Lin, Wei-Hsun Yang, Chun-Hsien Lin, Chun-Yu ChengIntroduction:Trans-pedicle screwfixation and posterolateral fusion forlumbar spondylolithesis is a well-established procedure. The accuracy ofscrew insertion is important for adequate

fixation and subsequent successfulfusion. Traditionally, screw insertion isdone under fluoroscopic guidance.However fluoroscopic views only providespatial information in 2 dimensions. Anovel approach to trans-pedicle screw(TPS) insertion is the combine use ofintraoperative computed tomography(iCT) and navigation technology forenhanced precision and safety of screwinsertion. The accuracy of screwplacement, time for computedtomography acquisition (for navigationregistration, screw placementconfirmation or adjustment) and patientsafety were evaluated in this study.Methods: From August 1, 2010 toSeptember 13, 2010, 15 patients withlumbar spondylolisthesis who underwentlumbar spinal fixation and posterolateralfusions with a total of 60 trans-pediclescrews were evaluated. The fixationaccuracy was evaluated by measuring thedistance of the screw tip to the anteriorvertebral body wall, the number ofpedicle fracture and screw revision weredocumented. The time spent for eachscrew insertion and for computedtomography acquisition were recorded.Results:The distance from screw tip toanterior vertebral body wall was 7.9±2.8mm. The time was 8.54±1.2 minutes foreach screw inserted and 4 minutes foriCT acquisition. Pedicle fracture occurredin 2 out of 60 screws (3.2%) and revisionwas done for 2 out of 60 screws (3.2%)without neurologic impairment.Conclusion:The results showed thatinstrumentation by trans-pedicle screwusing iCT with navigation systemtechnology can improve the precision offixation by enhancing the trajectory andpenetrance of screw into the vertebralbody, pedicle fracture does not occuroften, and it can be revised immediatelywithin the same operation.

456Computerized Image Guided SpineSurgery: The State-of-the-ArtJ. Patrick Johnson, Terrence T. Kim,Shoshanna S. Vaynman, Samer Ghostine,Michael Scott Turner, Kamal Ronald Woods, Marshall L. Grode,Srinath Samudrala, Robert S. PashmanIntroduction:Computerized image-guided spinal surgery has remainedlimited due to difficulties in applyingintraoperative navigational technologies,with its slow development over the pastdecades largely due to difficulties withregistration and inability to updateimaging intraoperatively. Specifically,complex spine surgery for uncommon

procedures has remained challengingdue to limitations of fluoroscopy, artifactsrelated to previous operations, anddifficult spatial orientation. We have beeninvolved in the development of severalgenerations of image-guidance surgery(IGS), whose application has recentlybeen facilitated with the latest advancesin intraoperative computer tomography(CT) imaging.Methods:We have applied IGS to nearlyevery application in the spine and nowreport our experience with CT-based IGSin 100 spinal procedures (50 thoracic, 35lumbar, 10 cervicothoracic junction, and5 sacral), considered complex anatomicand reconstruction problems. Patientswere positioned on a fluoroscopicoperating table to allow intraoperative CTimaging with the Medtronic O-arm.Standard fluoroscopic localization ofsurgical level(s) was confirmed and theCT scanner was positioned for image dataacquisition, with an automaticregistration process working in tandemwith the image-guidance system forsurgical navigation. Tracking arraysoptimized trajectory and placement ofsurgical instruments, primarily the high-speed drill and screw placement.Accuracy was determined by recordingknown intraoperative landmarks with theIGS monitor and measuring thedifference.Results: All patients had successfulimage-guided procedures to achieve thedesired surgical goal, with a 0% revisionrate for infection, screw malpositioning,or hardware failure. Registration wasaccomplished with a remarkably highaccuracy. Procedure adequacy can alsobe determined using IGS and post-procedure CT imaging.Conclusion: IGS has made significantadvances in ease-of-use, primarily due toautomatic registration developed to beintrinsic to the technology. Thistechnology has great potentialapplication for routine spinal procedures,less invasive techniques, to ultimatelyreduce morbidity and improve outcomes.

457Pressure Dynamics in the CervicalPrevertebral Space Related to thePresence and Absence of an AnteriorCervical Plate in an Ex Vivo ModelJ. Frederick Harrington, Elizabeth KenneyIntroduction: Prolonged dysphagia afterACDF is common. Anterior plate profile isconsidered to be a factor related to localpressure on, or deformation of theesophagus. We tested whether a typicalanterior cervical plate will create different




local pressure changes compared with anuninstrumented spine in the prevertebralspace in an ex vivo system.Methods: Sawbone cervical spines werepotted in acrylic To C2 rostrally and C7caudally. A 1mm diameter pressuretransducer was placed in contact at theC45 disc space level with and without ananterior cervical plate at C45 without asimulated esophagus. The spine wasencased in 15% gelatin to simulate softtissue. Pressure readings were obtained inneutral and 10 Degrees of flexion andextension.Results: Extension results in increasedpressure and flexion a decrease. With thesensor facing in and contacting the spinein the presence of a plate, pressureincreased an average of 76mmHg inflexion and decreased an average of107mmHg in flexion, while without aplate pressure changes were 4mmHgincreased in extension and decreased2mmHg in flexion. Neutral positionpressures were lowest in uninstrumentedspines.Conclusion: Anterior cervical platesincrease local pressures in theprevertebral space. Pressure increases inoccur in extension and neutral positionand are greater in instrumented spines.

458Dynamic Stabilization for DegenerativeSpondylolisthesis: Evaluation ofRadiographic and Clinical OutcomesLi-Yu Fay, Jau-Ching Wu, Wen-Cheng Huang, Henrich ChengIntroduction:Dynamic stabilization is asan option in the treatment of lumbarspondylosis but its effect on degenerativespondylolisthesis remains unclear.Methods:This retrospective studyincluded a cohort of 38 patients (meanage 63.7 years) with one- or two-levellumbar spinal stenosis who underwentlaminectomy and Dynesys dynamicstabilization system. Preoperatively, 24had degenerative spondylolisthesis whilethe other 14 had no instability but onlystenosis. Mean follow-up was 17.5months (range, 12-29 years). Pre- andpostoperative radiographic evaluationsand clinical outcomes were analyzed.Results:The mean range of motion(ROM) at the index level was reducedsignificantly from 10.0°±3.3°preoperatively to 2.8°±1.9°postoperatively (p<0.001). Screwloosening occurred in 13.3% of levels,21.1% of patients, and 4.6% of screws.There were no significant differencesbetween patients with and withoutspondylolisthesis in pre- andpostoperative ROM, and screw looseningrates per level, per patient, and per screw

(p=0.693, 0.358, 0.105, 0.385, and 0.671,respectively). Overall, the mean VisualAnalogue Score (VAS) improvedsignificantly from 6.0±3.2 to 2.9±3.4(p<0.001) and the Oswestry DisabilityIndex (ODI) scores improved significantlyfrom 50.6±19.5 to 28.8±24.6 (p<0.001)compared to preoperative scores. Therewere no significant differences in pre-and postoperative VAS and ODI scoresbetween the non-spondylolisthesis andspondylolisthesis groups (p=0.361, 0.120,0.964, 0.113, respectively).Conclusion:There are significantrestrictions in segmental range of motion(<3°) and clinical improvement afterlaminectomy and dynamic stabilizationwith Dynesys for symptomatic lumbarspinal stenosis. Radiographic findings,screw loosening rates, and clinicaloutcomes are all similar. The dynamicstabilization system provides equalradiographic stability and clinical effectsfor patients regardless of preoperativedegenerative spondylolisthesis.

459CO2 Laser-Assisted Lumbar Fusions:Safety, Clinical Outcomes and TechnicalConsiderationsAlan T. Villavicencio, Ewell Lee Nelson,Alexander Mason, Jason Babuska, Frances A. Carr, Sharad Rajpal, Sigita Burneikiene



FUTURE NEUROSURGERY AMBASSADOR




Introduction:The purpose of this studywas to evaluate potential technicaladvantages of the CO2 laser technology inopen transforaminal lumbar interbodyfusion (TLIF) surgeries and report ourpreliminary clinical data on the safetyand clinical outcomes.Methods: Safety and clinical outcomeswere compared between two groups: 24patients that underwent CO2 laser-assisted one-level TLIF surgeries and 30patients that underwent standard one-level TLIF surgeries without the laserperformed from November of 2008 toNovember of 2009. The safety of spinesurgeries was assessed by monitoring allintraoperative and perioperative surgicaltechnique related complications. Inaddition, MRI scans were reviewed forpossible laser-related thermal injurycomplications. The efficacy wasevaluated by documenting andcomparing postoperative lower back andleg pain (10-point Visual Analog Scale,VAS).Results:There were no neural thermalinjuries or other intraoperative laser-related complications encountered in thiscohort of patients. At a mean follow up of6.5 months, significantly reduced lowerback pain scores (P=0.002) were reportedin the laser-assisted patient groupcompared to standard fusion patientgroup. The lower extremity(ies) radicularpain intensity scores were similar in bothgroups. Laser-assisted TLIF surgeriesshowed a tendency (P = 0.07) of shorteroperative times that was not statisticallysignificant.Conclusion: Based on this preliminaryclinical report, the safety of the CO2 laserdevice for lumbar fusion surgeries wasdemonstrated. There were no neuralthermal injuries or other intraoperativelaser-related complications encounteredin this cohort of patients. Furtherinvestigation of CO2 laser-assistedlumbar fusion procedures in aprospective randomized fashion iswarranted.

460Use of a Novel Ultrasonic Bone Scalpelfor Osteoplastic Laminoplasty in theResection of Intradural Spinal CordPathologyScott L. Parker, Ryan M. Kretzer, Pablo F. Recinos, George I. Jallo, Violette Renard RecinosIntroduction:Osteoplastic laminoplastyis a well described alternative tolaminectomy in the treatment of spinalpathology. Recent studies have shownthat laminoplasty may decrease the

incidence of progressive kyphoticdeformity when used in the setting ofintradural spinal cord tumor resection,especially in the pediatric population[1,2]. A novel device, the BoneScalpel™by Aesculap (Figure 1), is an ultrasonicosteotome that precisely cuts bone whilepreserving the underlying soft tissues. Inthe case of laminoplasty, this potentiallyreduces the risk of dural laceration. Inaddition, the device allows for fineosteotomies as narrow as 0.5 mm, whichmay facilitate better postoperative bonehealing.Methods:We present our experience with11 patients who underwent osteoplasticlaminoplasty using the BoneScalpel™ inthe setting of intradural pathologybetween January 2009 and September2010. Following lesion resection, titaniumplates were used to reconstruct thelamina. The technical advantages andprocedure-related complications of usingan ultrasonic bone osteotome in theresection of intradural spinal cord lesionswere analyzed.Results: Successful laminoplasty wascarried out in all 11 cases (Table 1). Onecase of incidental durotomy was notedfollowing use of the device, which wasrepaired primarily without neurologicalor clinical sequelae. There were no casesof perioperative complications such aswound infection or CSF leak. There wasalso no incidence of immediatepostoperative spinal instability (Figure 2).Conclusion:The BoneScalpel™ byAesculap is a safe and technically feasibledevice for performing osteoplasticlaminoplasty. It allows for a narrowerlaminar trough to be performed thanconventional drilling, which may lead toimproved laminar healing and preventdelayed post-laminectomy kyphosis.Further studies and longer clinical follow-up are needed to delineate the true role ofthis device in the treatment of spinal cordpathology.

461Modification of the Prestige ST CervicalArtificial Disc to Allow Multi-levelImplantationKenneth Pettine, Christian SchlichtIntroduction:The purpose of thisabstract is to describe a modification ofthe Prestige ST implant to allow multi-level implantation in any patient. Thesecond purpose is to report the safety andefficacy of this modification. The PrestigeST implant has anterior phalanges withscrew fixation into the superior andinferior vertebral body that requires a

minimum 15mm of vertebral body heightto allow multi-level implantation.Modification dovetails the phalangesrequiring only 8mm of vertebral body formulti-level implantation. Utilizing thePrestige ST implant in a multi-levelfashion is an FDA off-label use of thedevice. There are currently two cervicalFDA approved artificial discs. Each hasunique characteristics. The ProDisc-Cimplant allows multi-level implantationwithout modification.Methods: Every patient from 2007 to April2010 who underwent a multi-levelPrestige ST implant was evaluated andsubdivided into groups with (two levels =10 patients, three levels = 2 patients) andwithout (two-level = 28 patients, three-level = 2 patients) modification. Therewas no significant difference in thedemographics between the groups. Thefollowing illustration demonstrates themodification. Modification of the PrestigeST implant is achieved with a high-speedDremel saw in approximately one minutefollowed by smoothing of the edges. Theimplant is modified such that the lockingscrew can still be utilized. Our experienceis that approximately 40% of male patientand 0% of female patients can undergo amulti-level non-modified Prestigeimplant.Results: In both groups, range of motionaveraged 8º at each implant level. Therewere no implant problems in eithergroup.Conclusion:Our experience indicatesmodifying the Prestige ST implant allowsfor use in a multi-level fashion in allpatients who have a vertebral body heightof at least 8mm. The clinical results ofpatients with a modified Prestige STimplant are equal to the patients withnon-modified implants.

462Management of GiantPseudomeningoceles After Spinal SurgeryEnayatkhater Omar ElkelanyIntroduction: Pseudomeningoceles are arare complication after spinal surgery,and studies on these complex formationsare few.Methods: Between October 2000 andMarch 2008, 11 patients who developedsymptomatic pseudomeningoceles afterspinal surgery were recruited. In thisretrospective study, we reported ourexperiences in the management of thesecomplex, symptomaticpseudomeningoceles after spinal surgery.A giant pseudomeningocele was definedas a pseudomeningocele >8 cm in length.




We also evaluated the risk factors for theformation of giant pseudomeningoceles.Results: All patients were treatedsuccessfully with a combined treatmentprotocol of open revision surgery forextirpation of the pseudomeningoceles,repair of dural tears, and implantation ofa subarachnoid catheter for drainage.Surgery-related complications were notobserved. Recurrence ofpseudomeningocele was not observed forany patient at a mean follow-up of 16.5months. This result was confirmed bymagnetic resonance imaging.Conclusion:We conclude that acombined treatment protocol involvingopen revision surgery for extirpation ofpseudomeningoceles, repair of duraltears, and implantation of asubarachnoid catheter for drainage is safeand effective to treat giantpseudomeningoceles.

463Early Experience with Expandable PEEKSpacers for Interbody Fusion forDegenerative Lumbar DiseaseBenjamin Shin, Christoph Hofstetter, Eric H. Elowitz, Roger HartlIntroduction:To determine the clinicaland radiological efficacy of expandablePEEK Spacers in lumbar interbody fusionfor degenerative lumbar disc disease.Methods:This is a retrospective analysis

of 22 consecutive patients (median age66; 9 men and 13 women operated on in2009 and 2010) who underwent lumbarsingle-level interbody fusion withexpandable PEEK spacers in combinationwith posterolateral pedicle screw-rodinstrumentation. Silicated calciumphosphate substitute was used as thebone graft. Clinical outcomes wereevaluated using the Visual Analogue Scale(VAS) and the Oswestry Disability Index(ODI). In addition, disc height, Cobbangles, and total graft subsidence wereevaluated on pre-op, post-op, and at thelatest follow-up.Results: Significant improvement wasobserved only in VAS Back (8.06 vs. 5.03, p= .005) and VAS Leg pain (5.95 vs. 3.16, p=.028) from pre-op to follow-up. Cageswere expanded from 7 mm to a mean of11.09 ± 1.23 mm (S.D.). Review of pre-and postoperative CT scans revealed asignificant increase in the anterior discheight (7.37 mm vs. 11.8 mm, p = .001)and posterior disc height (4.40 mm vs.7.44 mm, p = .002). There was a non-significant tendency towards an increaseof the foraminal height (14.63 mm to15.97 mm, p = .125). The average totalgraft subsidence was 3.71 mm. The localdisc angle and lumbar lordosis did notchange significantly. At a mean follow-uptime of four months, radiographicparameters were unchanged except for

foraminal height which decreased by 2.62mm (p = .02).Conclusion:Our preliminary resultsindicate that stackable PEEK wafers forsingle level lumbar interbody fusionsrestore disk height and are associatedwith improvement in clinical outcome.More patients with longer follow-up areneeded to assess long-term clinical andradiological outcome.



RESIDENT EDUCATION PARTNER


PROGRAM AT-A-GLANCE

WEDNESDAYMARCH 9, 2011



1:30 – 5:30 PMPediatric Craniocervical Society Desert Conference Suite III

Special Course I – Coding Update and ReviewGrand Canyon 9

Special Course II – Masters in Spinal Surgery: WhatHas Experience Taught Me?Grand Canyon 10

Special Course III – Spinal DeformityGrand Canyon 11

Special Course IV – Advanced MISTechniques/Managing MISComplicationsDesert Conference Suite IV

Special Course V – Management of PerioperativePainGrand Canyon 13

Special Course VI – Update on Spinal Surgery inTurkeyGrand Canyon 12

Special Course VII – Cervical MyelopathyDesert Conference Suite VIII

6:00 – 8:00 PMOpening ReceptionSage Court

THURSDAYMARCH 10, 2011





7:00 – 9:30 AMScientific Session I – Evidence-Based Spine Surgery inthe Real WorldGrand Saguaro North

9:00 AM – 7:00 PMExhibit Hall Open and PosterViewingGrand Canyon Ballroom

9:30 – 10:15 AMBeverage Break and What’s NewSession IGrand Canyon Ballroom

10:15 AM – 12:30 PMOral Platform Presentations IGrand Saguaro North

12:30 – 1:25 PMLunch and What’s New Session IIGrand Canyon Ballroom

1:30 – 3:00 PMScientific Session II – Spinal Surgery ComplicationAvoidance and ManagementGrand Saguaro North

3:00 – 3:45 PMBeverage Break and What’s NewSession IIIGrand Canyon Ballroom

3:45 – 5:15 PMOral Poster Presentations IGrand Saguaro North

Oral Poster Presentations IIGrand Canyon 9

5:15 – 6:45 PMReception in the Exhibit HallGrand Canyon Ballroom

FRIDAYMARCH 11, 2011





7:00 – 9:00 AMScientific Session III – Evolution of Treatment forMetastatic DiseaseGrand Saguaro North

9:00 – 9:30 AMMayfield Awards andPresentationsGrand Saguaro North


9:30 – 10:15 AMBeverage Break and What’s NewSession IVGrand Canyon Ballroom

10:15 AM – 12:15 PMOral Platform Presentations IIGrand Saguaro North

12:20 – 12:30 PMAnnual Business MeetingGrand Saguaro North

12:30 – 2:30 PMLuncheon Symposium I – Revision Spine SurgeryGrand Canyon 9

Luncheon Symposium II –Neurosurgeon as CEO: BusinessAspects of Spinal SurgeryGrand Canyon 10

Luncheon Symposium III – Cranial-Cervical JunctionGrand Canyon 11

Luncheon Symposium IV – Geriatric SpineGrand Canyon 12

Luncheon Symposium V – Spinal ArthroplastyGrand Canyon 13

1:30 – 5:30 PMSpecial Course VIII – Peripheral Nerve Exposures andNerve Repair TechniquesDesert Conference Suite III

Special Course IX – Evaluation and Management ofthe Spine Trauma PatientDesert Conference Suite IV

SATURDAYMARCH 12, 2011





6:55 – 8:15 AMOral Posters Presentations III Grand Saguaro North

8:20 – 9:40 AMDavid Cahill MemorialControversies SessionGrand Saguaro North


9:40 – 10:25 AMBeverage BreakGrand Canyon Ballroom

10:25 – 11:05 AMFellowship Awards and UpdatesGrand Saguaro North

11:05 AM – 12:35 PMOral Posters Presentations IVGrand Saguaro North

Special Thanksto These Companies for Providing an Educational Grant in Support of the 2011 Annual Meeting!

NEUROSURGICAL EDUCATION AMBASSADOR:

NEUROSURGICAL LEADERSHIP AMBASSADOR:

FUTURE NEUROSURGERY AMBASSADOR:

RESIDENT EDUCATION PARTNER:

ANNUAL MEETING SUPPORTERS:

as of February 23, 2011

11DSPN_SP_Cover_F021811:Cover 2/23/11 7:50 PM Page 2

27th Annual Meetingof the AANS/CNS Section onDisorders of the Spine andPeripheral Nerves

March 9-12, 2011JW Marriott Desert Ridge

Phoenix, Arizona

Scientific Program

Evidence-Based Spine Surgery in the Real World

Save the Date!

2012 ANNUAL MEETING OF

THE AANS/CNS SECTION ONDISORDERS OF THE SPINE AND

PERIPHERAL NERVES

March 7-10, 2012The Walt Disney World

Swan and Dolphin ResortOrlando, Florida

27thAnnual M

eeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves SCIENTIFIC PROGRAM

11DSPN_SP_Cover_F021811:Cover 2/22/11 4:59 PM Page 1

27 annualmeeting oftheaans/cnssectionon ... · oftheaans/cnssectionon disordersofthespineand...

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