Congenital Aural Atresia

Hwa J Son, M.D.

Faculty Advisor: Tomoko Makishima, MD, PhD

October 17, 2007

UTMB Otolaryngology

Grand Rounds Presentation

Epidemiology

• 1 in 10,000 to 20,000 live births

• Male > Female

• Right side > Left side

• Unilateral > Bilateral (3:1)

• Bony atresia > Membranous

Embryology

• 1st branchial groove forms meatal plate at 6

- 8 wks resorbs/forms EAC at 21st wk

• Auricle

– 1,2 BA

– 8 -12 wk

• Middle Ear

– 1,2 BA

– 5 -12 wk

• Inner ear

– otic capsule

– 3 - 20th

wk

Associated Ear Deformity

• Common

– Middle Ear

•Malleus/Incus fusion

– External Ear

•Microtia

•Severity of microtia correlates with

malformation of middle ear

• Uncommon

– Stapes footplate

– Inner Ear problems

Etiology

• Sporadic

• Syndromic (11-47%) – Goldenhar’s,

Treacher-Collins, branchio-oto-renal

syndrome, de Grouchy syndrome (18q-) and

Crouzon syndrome.

• Familial– within immediate family

4.9%, extended family 10.3%

Non-Syndromic Associations

• Facial asymmetry (36.5%)

• FN weakness (15.2%)

• Cleft lip/palate (4.3%)

• Urogenital defects (4%)

• CV malformation (2.5%)

• Macrostomia (2.5%)

• Congenital cholesteatoma (4-7%)

History

• Hx of teratogens

– microtia- thalidomide, isoretinoin,

vincristine, cholchicine, cadmium

• Family hx

• Hearing status, speech development,

past surgical procedures

• Frequency of otitis media

Physical Exam

• Location of condyle: posterior position

poor prognosis – atretic plate and ME

are poorly developed

• Size of mastoid (palpate mastoid tip,

spine of Henle, condyle, zygomatic

arch)

• Craniofacial anomaly

• Severity of microtia

Grades of Microtia

Schucknecht Classification

Audiological Assessment

• When: ABR within 2-3 months of birth

• Results

– Bone conduction usually normal

– Air conduction maximal at 60dB

• Intervention

- Normal or u/l confirm with behavioral

audiogram at 6 M age, no need for aid

- B/L: Need bone conduction hearing aid, early

speech therapy

Imaging

• When? At several months

• Look for

– Status of the inner ear

– Extent of temporal bone pneumatization;

– Course of the facial nerve

– Presence of the oval window/stapes footplate.

• Also important

– Size of bony atretic plate

– Soft tissue contribution to the atresia

– Size/status of the middle ear cavity

– Presence/absence of congenital cholesteatoma.

Example 1

Example 2

Jahrsdoerfer Grading System

Parameter Points

Stapes 2

Oval window open 1

Middle ear space 1

Facial nerve normal 1

Malleus-incus complex present 1

Mastoid well pneumatized 1

Incus-stapes connection 1

Round window normal 1

Appearance of external ear 1

Treatment Options

• Non-reconstructive option

– Bone conduction hearing aids

– BAHA

• Atresiaplasty +/- auriculoplasty

Non-Reconstructive Option

• Bone conduction hearing aid (BCHA)

– Ideally before age 6M for b/l CAA.

BAHA

• Surgically-implanted, percutaneous

titanium screw fixture

• Osseointegrates into the temporal

bone.

Advantages of BAHA

• Sound energy is not attenuated by the

skin and intervening soft tissues

• More comfortable at contact site

• Does not preclude

reconstruction later

on because of

surgical scars

Surgery for BAHA

• Needs 2-stage surgery in young

children (age 2-10)

– 1st: titanium screw

– 2nd

: 3M later, skin-penetrating abutment

• Complications limited to:

– local infection / inflammation (7.5%)

– failure to osseointegrate (2.5%)

BAHA Results

• Grandstrom(1993, L4)

– 100% subjective satisfaction and speech

thresholds <30 dB in 39 pt with J’s Score <6,

• Hakansson et al.(1995, L4)

– 147 pt. PTA <45 dB 89% with subjective

improvement.

– PTA 46-60 with 61% and PTA >60 with 22%

• Lustig et al.(2004, L4)

– 40 pt (9 w/ CAA) - ABG closure of <10 in 80%, <5

in 60%.

2004 BAHA Consensus

Statement (L5)

• BAHA best option when:

– ABG>30 with external canal occlusion

– tx resistant OM

• B/l case, give b/l

conductive aid before

age 6M

• Awaiting reconstruction:

– BAHA can be used in

children <2yo with

steel or elastic band

Reconstructive Surgery

Goal of Reconstructive Surgery

• Create a patent, skin-lined EAC

• Postoperative air-bone gap within 20

to 30 dB.

• Long term hearing result that is

adequate for speech/language

development in children

• Cosmetically appealing auricle

Difficulty of Surgery

• Altered anatomy, absence of

anatomical landmarks

• Fear of injuring FN

• SNHL from drilling

• Difficulty of placing skin graft

• Chance of meatal stenosis

• Concern of post-op infection

Staging of Surgery

• Stage 1: Cartilage graft harvest,

sculpturing, implantation

• Stage 2: Lobule repositioning (z-plasty

to more posterior/inferior)

• Stage 3: Elevation of auricle

• Stage 4: Tragus formation,

atresiaplasty

Contraindications

• Significant SNHL or inner ear malformation.

• Limited middle ear–mastoid pneumatization

or a significantly hypoplastic middle-ear

cleft.

• Anomalous facial nerve or aberrant major

vascular structure.

• Middle cranial fossa tegmen sagging

– Would restrict anatomic access to the middle-ear

cleft.

Timing of Surgery

• Start at age 6Y or later.

• Limitations for earliest date

– Rib cartilage maturation

– Post-op cooperation

• Reconstruction of auricle first

– Chance of success/healing best without

vascular compromise

• Operate on better ear first

Canaloplasty

Tympanoplasty, Skin grafting

Meatoplasty

Pitfalls

• Second genu makes acute angle turn

instead of 90°

– Vertical course crosses the middle ear

Follow-up Care

• Meatal suture out in 7 days

• Packing removed at 2 and 3 wks

• Antibiotic drops for 8-12 wks

• Audiogram at 8 wks, 6 M and yearly

• New ear canal must be debrided under

microscope q 6-12M

Final Cosmetic Result

Hearing Results

• Jahrsdoerfer (1992, L4)

– 90 operated on, 37 with grade 8-9.

– SRT <10 in 11% and SRT 10-25 in 78%

• Chandrasekhar (1995, L4)

– 92 pt, ABG <30 in 60% of primary and in 54% of

revision sx

• Murphy (1997, L4)

– 33% of partial atresia with SRT <20 dB and 15%

of total atresia

• De La Cruz (2003, L4)

– 116 ears, 58% ABG <30 for primary, 56% for

revision

Long Term Hearing

• De La ruz (2003, L4)

– 90 ears with >6M f/u.

– PTA: 59.9dB 45.3 dB 52.5 dB

– ABG: 45.1 dB 28.1 dB 32 dB

• Hearing gets worse long term, but not

statistically significant

• Ossicular chain refixation the most

common cause of HL

Results Summary

• Surgeon dependent

• What’s termed success varies between

studies

– May not be appropriate for pre-school

and school aged children (SRT <15 per

audiology literature)

Complication

• Lateralization of TM (22-28%)

– up to 12 M post-op

• Meatal stenosis (cartilagenous >

bony): 8-12%

• SNHL – inner ear damage (2%)

• Facial nerve injury (<1%)

• Fixation/discontinuity of ossicles

(11.5%)

Measures to Avoid Complication

• Lateralization of TM

– Cut off nitrous oxide 30 min before grafting.

– The graft anchored medially to the malleus and

the tab placed into the protympanum.

– Use of silastic button.

• Stenosis:

– Use of large STSG

– Merocel wicks

• SNHL:

– Caution with drilling,

– Use laser

• FN injury

– Intra-op monitor

“Surgery or implantable hearing

devices?”

Surgery vs. BAHA

• Evans (2006, L4)

• Compare hearing results, complications, cost

Reconstructed BAHA

2-stage

BAHA

1-stage

Hearing

gain

17.3 dB per ear 31.8 31.8

Cost $51506 $42449 $28341

Cost/dB $2909 $1238 $826

Results

• Cost

– BAHA covered by Medicare

– Cost about 1/4 of sx per dB gain

• Hearing

– 93% of reconstructive sx pt still needed some

form of sound amplification

– BAHA achieves HL <15dB with normal bone

curves

• Complications

– Reconstruction : Canal stenosis (22.2%), ROE

(19%), canal prolapse(5%), cholesteatoma (3%)

– BAHA with fewer serious complications: 1/6 with

hypertrophic scar

BAHA for Binaural Hearing

Use of BAHA in Unilateral CAA

• Wazen et al.

– Prospective case series with 9 pt.

• Pt benefited in tonal, spondee

threshold

• Significant improvement in handicap

score (from questionnaire)

• Gain binaural benefit in

localization/speech perception in

noise

Case Presentation #1

53 yo M with no other signif PMHx presents to B-clinic as a referral from

audiology. He has Left microtia s/p microtia repair? at age 9 in Mexico,

wearing BCHA on right side. He wishes to be re-fitted for another BCHA.

Case Presentation #1

Case Presentation #2

• RP is a 10 M old boy presenting to

pedi ENT clinic for f/u after failing OAE

as a newborn on Right side.

• PE showed left microtia with narrow

EAC at bony-cartilaginous junction.

Right side stenotic, TM not visualized

• ABR showed repeatable V-wave

– Left: <30dB HL air stimulation

– Right: <30dB bone stimulation

Conclusion

• Early identification of problem important for

hearing amplification and special education

• Patient classification with audio/CT

important for predicting results of sx

• Severity of microtia predict ME deformity

• BCHA should be fitted before age 6M for b/l

• BAHA with better audio results and

satisfaction than BCHA for non-sx candidate

• Sx needs careful planning with

multidisciplinary effort, careful timing

Conclusion

• Surgery

– Questionably adequate audio result for

children

• BAHA

– Good hearing results and more cost

effective for hearing gain

• Binaural BAHA

– Recommended for further gain in speech

in noise and localization

Bibliography

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