Congenital Aural Atresia

Elizabeth J. Rosen, MD

Faculty Advisor: Arun K. Gadre, MD

The University of Texas Medical Branch

Department of Otolaryngology

Grand Rounds Presentation

January 8, 2003

Congenital Aural Atresia

Embryology

Classification

Evaluation

Surgical Repair

Results

Complications

Controversies

Congenital Aural Atresia

Definition: “a birth defect that is

characterized by hypoplasia of the external

auditory canal, often in association with

dysmorphic features of the auricle, middle

ear and, occasionally, the inner ear

structures” --Harold F. Schuknecht, 1989

Congenital Aural Atresia

Incidence: 1 in 10,000-20,000

Unilateral 3-5x more common than Bilateral

Males > Females

Right > Left

Inheritance—sporadic Autosomal recessive or dominant

Congenital Aural Atresia

Associations

– Hydrocephalus

– Posterior cranial

hypoplasia

– Hemifacial microsomia

– Cleft palate

– GU anomalies

Syndromes

– Treacher-Collins

– Goldenhar’s

– Crouzon’s

– Mobius’

– Klippel-Feil

– Fanconi’s

– DiGeorge

– Pierre Robin

– VATER

– CHARGE

Embryology

Auricle

– 4th week of gestation

– 1st and 2nd branchial arches

– Hillocks of His

1—tragus

2—helical crus

3—helix

4—antihelix

5—antitragus

6—lobule

Embryology

External Auditory

Canal

– 8th week of gestation

– 1st branchial groove

– Medial migration of a

solid core of epithelial

cells

– Recanalization during

6-7th months of

gestation

Embryology

Ossicles

– 4th week of gestation

– Meckel’s cartilage

Malleus head and neck

Incus body and short

process

– Reichert’s cartilage

Malleus handle

Incus long process

Stapes suprastructure

Embryology

Labyrinth

– 3rd week of gestation

– Invagination of otic

placode to form otic

vesicle

– Semicircular canals—

6th week

– Utricle and Saccule—

8th week

– Cochlea—7-12th weeks

Embryology

Facial Nerve

– 4-5 weeks of gestation

Classification Altmann’s

– Grade I

Hypoplastic EAC, temporal bone, TM; normal or slightly hypoplastic middle ear cleft; normal or slightly deformed ossicles

– Grade II

Absent EAC; small middle ear cleft; osseous atresia plate; fixed and malformed ossicles

– Grade III

Absent EAC; markedly hypoplastic or absent middle ear cleft; absent or severely deformed ossicles

De la Cruz

– Minor

Normal mastoid

pneumatization

Normal oval window

Reasonable oval window-

facial nerve relationship

Normal inner ear

– Major

Poor pneumatization

Absent or abnormal oval

window

Abnormal horizontal facial

nerve

Anomalous inner ear

Classification Schuknecht

Type A

Type B

Type C

Type D

Classification

Jahrsdoerfer, 1992

– Based on HRCT

temporal bone findings

– Score correlates to

likelihood of

successful surgery

Evaluation

History

– Details of pregnancy

– Family history

Physical Examination

– Microtia

– Severity of EAC stenosis

– Craniofacial development

Evaluation

Audiologic Evaluation—ABR before

leaving the hospital

– Unilateral atresia

Auditory function of the “normal” ear

– Bilateral atresia

Establish presence of cochlear function

FIT WITH BONE CONDUCTION AID

Evaluation

High Resolution CT Temporal Bone

– Age 5-6 years

– Axial and Coronal

– Evaluate

Middle ear and mastoid pneumatization

Anatomy of ossicles

Inner ear morphology

Course of facial nerve

Surgical Repair

Candidacy

– ABSOLUTE REQUIREMENTS

1. Normal inner ear

2. Normal cochlear function

– HRCT Score

</= 5/10: poor

6/10: marginal

7/10: fair

8/10: good

9/10: very good

10/10: excellent

Surgical Repair

Timing

– Microtia repair should be performed prior to

undertaking atresia repair

– 5-6 years of age

– Controversy:

Between Stages 2 and 3 of microtia repair

2 months after completion of microtia repair

Surgical Repair

Transmastoid Approach

– Infrequently used

– Advantages:

More familiar approach

Identification of sinodural angle and lateral SCC as

landmarks

– Disadvantages:

Creation of mastoid cavity

– Larger defect to be skin grafted

– Prolonged healing

– Lifelong maintenance

Surgical Repair

Anterior Approach

– Popularized by Jahrsdoerfer, most frequently

utilized approach

– Advantage:

Avoidance of mastoid cavity

– Disadvantages:

Unfamiliar approach

Lack of landmarks

Surgical Repair

Video

– American Academy of Otolaryngology—Head

and Neck Surgery Foundation

Congenital Disorders—Volume #4

Harold F. Schuknecht, MD

Results

Difficult to interpret

– Different classification

of atresia

– Different criteria for

surgical candidacy

– Different definition of

“successful” outcome

– Different periods of

follow-up

Results

Stability of Hearing Levels

– Lambert, 1998

– Early postoperative period (<1yr)

60% 25dB or better

70% 30dB or better

– Prolonged follow-up (1-7.5yrs)

46% 25dB or better

50% 30dB or better

Complications EAC restenosis

– Highly variable: 8-50%

– Correlation to severity of atresia

TM lateralization

– 5-26% of cases

– Easier to prevent than to correct

Chronic infection

– Reconstructed EAC lacks normal keratin migration and cerumen production

– Create wide meatus, fix restenosis, frequent follow-up with canal debridement

Complications

Facial Nerve Injury

– 1.0-1.5%

– Vulnerability

Skin incision

Dissecting in the glenoid fossa

During canalplasty

Transposing the nerve

Dissecting preauricular soft tissue

– Prevention

Preoperative evaluation of HRCT

Intraoperative facial nerve monitoring

Complications

Sensorineural Hearing Loss

– Up to 15% of cases

– 4,000-8,000 Hz

– Acoustic trauma to the inner ear

Transmission of drill energy

Drill injury to ossicles

Manipulation of ossicular chain

– Avoidance—Meticulous technique

Controversies

Surgical Repair of Unilateral Atresia

– Historically

One hearing ear = normal speech and language development

No indication for surgery

– Recently

Unilateral hearing loss = auditory, linguistic and cognitive deficits

Improved preop evaluation, patient selection, surgical techniques, predictable results

Surgery indicated

Controversies Timing of Unilateral Repair

Conclusion

Complex and Challenging Problem

Goals:

– Restore functional hearing

– Construct patent and infection-free EAC

Rewarding Surgery

Bibliography

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Surgery, D.E.Brackman, Ed. W.B. Saunders, Philadelphia; 1994.

•Kamerer, DB. Congenital and Acquired Atresia of the External Auditory Canal. In, Operative

Otolaryngology, Head and Neck Surgery, E.N.Meyers, Ed. W.B. Saunders, Philadelphia; 1997.

•Schuknecht, HF. Congenital Aural Atresia. Laryngoscope, 99; Sept 1989: 908-917.

•Lambert, PR. Congenital Aural Atresia. In, Head & Neck Surgery—Otolaryngology, 2nd Ed,

B.J.Bailey, Ed. Lippincott-Raven, Philadelphia; 1998.

•Bauer, GP, Wiet, RJ, Zappia, JJ. Congenital Aural Atresia. Laryngoscope, 104; Oct 1994: 1219-

1224.

•Jahrsdoerfer, RA, et al. Grading System for the Selection of Patients with Congenital Aural

Atresia. Am J Otology, 13 (1); Jan 1992: 6-12.

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and Surgeon Need to Know. J Comput Assist Tomogr, 20 (5); Sept/Oct 1996: 724-731.

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Children. Am J Otology, 19 (5); 1998: 679-686.

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Dec 1998: 1801-1805.

•Jahrsdoerfer, RA, Lambert, PR. Facial Nerve Injury in Congenital Aural Atresia Surgery. Am J

Otology, 19 (3); 1998: 283-287.

•Lambert, PR, De la Cruz, A, Choo, DI. Management of the Unilateral Atretic Ear. In,

Controversies in Otolaryngology, M.L.Pensak, Ed. Thieme, New York; 2001.