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Surgery for Congenital Aural Atresia and Stenosis
Built from Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
What’s inside
11 sections · 143 slides
Overview
- Scope of this presentation
Epidemiology and embryology
- 1 in 10,000-20,000 live births More often unilateral Higher prevalence in males Syndromic in about 10% of patients Inherited in about 5% of non-syndromic cases Middle ear pathology tracks auricular deformity
- Treacher Collins syndrome Goldenhar syndrome Hemifacial microsomia Together about 10% of atresia patients Remainder are non-syndromic
- First branchial arch anomaly Malleus and incus typically malformed and fused Stapes usually preserved Inner ear usually preserved Different embryologic origins explain the sparing
- Second gestational month: first branchial pouch epithelium Epithelium migrates medially Canalization in the 6th-7th months Failure of canalization gives atresia No external auditory canal is formed
- No external auditory canal present TMJ to mastoid tip distance markedly narrowed Facial nerve courses more anterior and lateral Middle ear cleft underdeveloped to varying degree Tympanic membrane absent
- Pathogenesis of the conductive loss
Congenital aural canal stenosis
- Ear canal present but diminutive Distinct from complete atresia May be associated with hearing loss Cholesteatoma formation is the key risk Schuknecht described four types of canal stenosis
- Type A: canal stenosis, relatively normal middle ear Type A needs meatoplasty or risks cholesteatoma Type B: partial atresia, stenotic canal Type B: rudimentary tympanic membrane often visible Type B: middle ear abnormalities more common
- About 20% of stenotic ears develop cholesteatoma Canal diameter < 2 mm: 50% by age 20 (Cole, Jahrsdoerfer) Debris collects behind the narrow segment Can progress far before it is detected Silent growth is the danger
- High-resolution temporal bone CT at 4-5 years of age Scan earlier if otorrhea, pain or swelling Scan earlier for facial weakness or vertigo Surveillance scanning continues into adulthood Close clinical evaluation alongside imaging
- Canalplasty technique overlaps in both conditions Stenosis retains residual ear canal skin That skin may allow canalplasty without a skin graft Atresia always needs fascia and split-thickness skin graft Stenosis surgery is intrinsically distinct
History and classification
- Atresia identified in prehistoric skulls Surgical repair reported only from the late 1940s-1950s Fenestration of the lateral semicircular canal used early Canalplasty and type III tympanoplasty also described All opened the mastoid cavity
- Group I: normal or stenotic canal, hypoplastic cleft Group I: endaural approach to widen the canal Group II: fistulous tract or complete atresia with bony plate Group II: open antrum, aditus, attic; free the ossicles Group III: atresia with nonpneumatized mastoid, middle ear Group III: surgery advised against
- Type A: meatal atresia, fibrocartilaginous canal stenosis Type B: partial atresia, stenotic canal, middle ear anomaly Type C: complete absence of EAC with middle ear malformation Type D: complete atresia with poor pneumatization Type D patients are not canal surgery candidates
- Schuknecht classification
- First described in 1978; the modern standard Avoids opening the mastoid air cells Drilling kept anterior and superior Follows tegmen and TMJ into the epitympanum Atretic bone picked away; ossicles freed Temporalis fascia onlay over the mobile native chain
- No open cavity to maintain Lower risk of postoperative drainage Fewer complications than older techniques Native mobile ossicular chain preserved Significantly improved hearing results
- Minor: normal ear canal and tympanic membrane Minor: congenital stapes fixation, malleus bar Minor: absent incus long process or oval window Minor: single stapes crus Major: absent canal and drum with underdeveloped cleft
- Formidable operation; rigorous preoperative assessment Intraoperative decision-making is constant Facial nerve injury risk higher for the inexperienced Sensorineural hearing loss risk likewise Stable long-term ABG closure is difficult
Patient selection
- Assesses mastoid and middle ear aeration Assesses position of the tegmen Assesses ossicular morphology Assesses course of the facial nerve Broadened surgery to unilateral atresia
- Temporal bone CT in favourable and unfavourable atresia
- Audiometric evidence of normal cochlear function Normal bone conduction thresholds required Imaging evidence of normal inner ear architecture Inner ear develops from a separate anlage Cochlear function is typically normal
- Non-aerated middle ear and mastoid Low-hanging tegmen obstructing the corridor Facial nerve course placing the nerve at great risk Jahrsdoerfer score of 5 or below Absent or abnormal inner ear
- Otitis media with effusion generally clears within 1 year Primitive mesenchymal tissue is fibrous and gelatinous Mesenchyme seen with absent or poor Eustachian tube function Repeat CT in 1-2 years to distinguish Soft tissue persisting 2 years: surgery not recommended
- Ten-point scale based on preoperative HRCT Individual anatomic structures score points External ear appearance is also scored Auricular and middle ear development correlate Designed to select the best surgical candidates
- Grading system of candidacy for surgery of congenital aural atresia from Jahrsdoerfer et al.
- Score 8/10 or more: SRT < 30 dB in 89.2% Score 7/10: 72.4% Score 6/10: 41.1% Score 5/10: 0% Most operated patients score 7 or 8
- Candidacy thresholds on the Jahrsdoerfer scale
- Success defined as postoperative SRT 30 dB HL or better Attainable in 75-80% of carefully selected patients Selection sorts out the high-risk, poor-result patients Poor anatomy on HRCT predicts low likelihood of success Normal or near-normal hearing is the goal
- Occurs in about 4% of patients No way to diagnose it preoperatively Options: abort the operation, or stage it Abort: close without fascia or skin graft Stage 2: mobilize or stapedectomy with ossiculoplasty Decision made intraoperatively with the family
- Fixed stapes found at surgery
Counselling and hearing rehabilitation
- Age at initial counseling matters Families often focus first on the microtia Explain differences and timing of the two operations Involve an experienced auricular reconstructive surgeon early Discuss cosmesis, hearing, and number of surgeries Long-term follow-up for cleaning and surveillance
- High risk of speech delay, particularly if bilateral Lower scholastic success documented Unilateral loss also causes subtle difficulties Amplification emphasised at every age and stage Amplification regardless of the surgical decision
- Older literature offered surgery only in bilateral atresia Argument: unlikely to produce serviceable hearing Risks of facial nerve injury and SNHL outweighed benefit Meatal stenosis and unstable hearing cited against it Unilateral cases deferred to adolescence
- Unilateral patients may be operated under strict criteria Selection excludes patients HRCT predicts will do badly Bilateral criteria historically more lenient Reliable osseointegrated devices removed that rationale Criteria should now be the same in both groups
- Softband Baha and SoundArc (Cochlear Corp.) ADHEAR (MED-EL) Consider placement within 3-6 months of life Used while awaiting atresiaplasty or an implant Most bilateral patients develop excellent speech
- Percutaneous: BAHA System, Ponto System Transcutaneous: Bonebridge, Osia, Sentio For non-candidates or failed atresiaplasty Newest transcutaneous devices fully implanted Larger footprint than a percutaneous abutment
- Transcutaneous devices generally MRI conditional Magnetic artifact obscures the ipsilateral head Consider the recipient's future need for MRI Sufficient bone stock required at any age Device must not interfere with auricular reconstruction
- Atresiaplasty compared with bone conduction implantation
- Nadaraja meta-analysis of 107 studies Postoperative SRT, PTA and ABG significantly better Individual device studies show similarly good results Single-stage device cheaper than uncomplicated surgery Cost excludes complications and missed work or school
- Hearing without an outwardly visible component External device may be stigmatizing Improved sound localization after canalplasty Benefit shown predominantly with ipsilesional stimuli Failed surgery still leaves a canal for a hearing aid
Microtia and operative sequencing
- Grade I microtia
- Grade II microtia
- Grade III microtia
- Auricular prosthesis with adhesive or titanium posts Porous polyethylene implant, e.g. Medpor Autologous rib cartilage framework Prostheses: minimal morbidity, lifelike cosmesis Prosthesis preferred after failed autogenous repair
- Template made from the implant to match the other ear Subcutaneous pocket created inferiorly for the implant Large temporoparietal fascia flap draped over it Suction holds the flap to the implant Skin grafts cover superior and posterior implant
- Fracture of the framework Framework exposure Loss of the temporoparietal fascia flap Injury to the frontal branch of the facial nerve Implant acquires no vascular supply of its own
- Stage 1: harvest seventh and eighth costal cartilage Margin of sixth rib cartilage also taken Framework sculpted and buried in a subcutaneous pocket Suction drains hold thin skin down onto the cartilage Few surgeons have mastered the series
- Lobule transposition about 3 months later Stage 3: framework elevated off the lateral skull Thick split- or full-thickness graft for the sulcus Atresia repair after the third or fourth stage Tragus created in the fourth stage
- Autologous tissue, so no concern for rejection Cartilage and soft tissue gain robust blood supply Little concern for exposure, infection or extrusion Atresia surgeon can carve cartilage for a wide meatus Criticised for framework definition and projection
- Reconstructive surgeon must operate first A virgin field is imperative for the rib graft Scar and a compromised vascular bed make it far harder Bony canal is drilled in the same place every time Reconstructed auricle can be repositioned to align
- Atresia repair must precede polyethylene reconstruction Implant would not heal if exposed at atresia surgery Reconstruction is then built around the new bony canal Skin graft sutured to native skin where the canal exits Concern remains if revision atresia surgery is needed
- Operative sequencing by reconstructive method
- Usually delayed until about 6-7 years of age Allows rib cage growth for costal cartilage harvest A child large for age may be operated earlier Grade I or II without reconstruction: atresia surgery at 5 Only if the child is cooperative
- Maturity needed for postoperative dressing changes Packing removal and canal cleaning require cooperation A poor result can be salvaged in the office if the child helps Younger children: more Eustachian tube dysfunction Younger children: higher rate of meatal or canal stenosis Not yet troubled psychologically by the deformity
- Bilateral: bone conduction ABR to confirm cochlear function Bone conduction device as soon as possible after birth Supports receptive and expressive language development Unilateral: device trial after confirming cochlear function Hearing checked twice yearly for 2-3 years, then annually
- Present in 6.3-48% of patients with aural atresia Infectious symptoms or otalgia warrant CT at any age MRI with diffusion weighted imaging to confirm Surgical treatment precedes auricular reconstruction May also form years after atresia or microtia repair
- Atresia with extensive cholesteatoma on CT and diffusion weighted MRI
Surgical technique
- Supine, operated ear turned away Ipsilateral arm tucked loosely as graft donor site Arm brought onto an arm board mid-case No blood pressure cuff on the donor arm Half-inch swath of hair shaved around the ear 1% lidocaine with 1:40,000 epinephrine postauricularly
- Operation takes 3-5 hours Urethral catheterization not always used Short-acting paralytic for induction only No paralytic during the operation Facial nerve monitoring mandatory in every case No nitrous oxide: balloons the fascia graft
- Used by some surgeons for planning the neocanal Confirms the ossicular mass without surface landmarks Helpful where landmarks are absent Not necessary for surgical success
- Postauricular incision down to temporalis fascia Quarter-sized fascia harvested, scraped, dehydrated Periosteal incision along the linea temporalis Perpendicular anterior incision along the glenoid fossa Cuff of periosteum left at the glenoid fossa Periosteum retracted posteriorly, auricle anteriorly
- Preoperative markings for canalplasty in Grade III microtia
- Planned incision and boundaries of the neocanal
- Mastoid tip, temporal line and glenoid fossa Periosteal elevation carried anteriorly to the fossa Identifying the glenoid fossa is critical A cortical dimple may mark the drilling site Elevate anterior to the dimple to confirm the fossa Cribriform area is often a reliable surface landmark
- Begin with a 5 mm cutting burr, continuous irrigation Stay anterior and superior throughout Identify the tegmen superiorly and follow it medially Hug tegmen above and glenoid fossa in front Avoid the mastoid antrum; open few air cells Prevents a cavity, infection and graft mucosalization
- Dense nonpneumatized atretic bone encountered medially Change to progressively smaller diamond burrs Start with a 3 mm diamond burr Aim to enter the cleft at the epitympanum Entry superior to the ossicles Avoids the commonly aberrant facial nerve
- Drill path into the epitympanum in the atretic ear
- Course of the facial nerve in the atretic temporal bone
- Nerve met while drilling posteriorly and inferiorly Short or absent vertical segment in about 25% Sharp anterior curve at the second genu Most vulnerable to injury in this location Thin vessels over thinned bone signal the nerve Facial nerve monitoring is a necessity
- Band of mostly periosteum may be encountered Runs through a bony defect in the wall to the TMJ Separates the atretic plate from the joint Easily confused with the facial nerve Recognition prevents needless abandonment
- Air space reached at about 1.5 cm depth Fused malleus-incus complex lies just inferiorly Body of the incus is usually the first landmark Gentle palpation confirms mobility Chain fixed medially and inferiorly at the malleus neck
- Fused malleus head and incus body in the opened epitympanum
- Drill to eggshell thickness with 3 and 2 mm diamonds Slow burr rotation over the ossicles Pick bone away with Rosen needle or dental excavator Sharp dissection lyses malleus periosteal attachments Last ligamentous attachments cut with a #59 beaver blade Laser may be used instead of the blade
- Remove bone 360 degrees around the chain Maximizes ossicular mobility Preserve bone around the fossa incudis Preserve anterior malleus soft tissue attachments These attachments support the chain Avoid subluxation and vibratory trauma
- Ossicular chain after complete removal of atretic bone
- Incus and malleus almost always fused Manubrium of the malleus often absent Long process of the incus highly variable What matters is that the incus attaches to a stapes Stapes superstructure may be monopedal Footplate mobility must be determined
- Congenital stapes fixation found in 4% Usual finding: well-formed stapes, mobile footplate Oval window may be smaller than normal Small oval window does not harm the reconstruction Nor does it affect the hearing result
- Lateral ossicular mass removed when the joint is discontinuous Chain reconstructed with a notched PORP PORP: partial ossicular replacement prosthesis Delivers superior results to other configurations Native chain preserved wherever possible
- Drill along tegmen
- Lower expired oxygen to less than 25% Room air FiO2 of 21% is best Reduces air diffusion into the middle ear Prevents ballooning of the fascia graft
- Drill bone peripherally to create room for the graft Center the malleus-incus complex in the canal Fascia trimmed to about 1.5 cm diameter Placed in overlay fashion onto the ossicular mass Tucked around the chain to prevent lateralization Edges reflected 1-2 mm up the canal wall
- New eardrum 1-1.5 times normal drum diameter Fascia must contact maximum ossicular surface area Opened large air cells plugged with temporalis muscle Prevents mucosalization of the graft
- Fascia, skin graft and Silastic disc in the neocanal
- 2-inch dermatome blade, 0.006-0.015 inch thickness Donor: medial upper arm or ipsilateral thigh Too thick: graft curls and is hard to place Too thin: graft sloughs under environmental pressures Thin border used at the level of the eardrum Thicker border sutured to the new meatus
- Graft cut to 4 x 5 cm Medial edge notched in triangular or circular fashion Lateral notches ease sewing into the meatoplasty Notched edges aligned over the temporalis fascia Entire fascia graft covered by squamous epithelium Vertical slit faces anteriorly
- Split-thickness skin graft with medial and lateral tabs
- Overlap of skin graft and fascia graft in the neocanal
- 0.04 inch Silastic cut into a circular disc Placed over the new tympanic membrane Holds notched skin edges and prevents blunting Four to five Merocel wicks trimmed to 3/4 length Medial canal packed to the bony opening Wicks hydrated with ofloxacin solution
- Silastic disc, Merocel wicks and graft suturing at the meatus
- A thin tympanic membrane and a thin skin graft Fascia tucked around the chain, not resting on it 1-2 mm fascia overlap onto the canal wall Adequately sized Silastic disc Tight packing of the neocanal Bony clearance around the ossicles
- Sequence of the reconstruction
- A hasty meatoplasty can ruin a flawless operation Meatal stenosis is the resulting failure First priority: meatus and auricle aligned to bony canal The bony canal cannot move; the auricle can Auricle repositioned in about half of patients Usually in a posterosuperior direction
- Elevate superiorly by releasing skin over parotid fascia Release also over the sternocleidomastoid inferiorly Stay superficial to avoid entering the parotid gland Parotid entry risks a salivary fistula Move posteriorly by excising postauricular skin Auricle sutured to the new postauricular skin edge
- U-shaped incision in the conchal bowl skin Flap based anteriorly at the tragus Underlying cartilage and soft tissue cored out Flap brought medially through the new meatus Sutured to the TMJ periosteal cuff with 4-0 Vicryl Forms the lateral anterior canal wall
- Postauricular incision tacked with 3-0 undyed Vicryl Skin graft delivered through the meatus Sutured to native conchal skin superiorly and posteriorly Also inferiorly; conchal flap is the anterior wall 5-0 fast-absorbing gut sutures used Lateral canal packed with full-length Merocel wicks
- Lateral skin graft delivered through the meatus Sutured to native postauricular skin Postauricular incision closed around the new meatus Anterior skin or cartilage excised to align the meatus Lateral canal packed with 3/4 length Merocel wicks
- X marked over the neocanal, four triangular flaps raised Subcutaneous tissue removed under each flap Palva flap split horizontally to clear the neocanal Pressed fascia laid on the ossicular mass with overlap Triangular flaps sutured down to periosteum Skin graft tabs sewn into the triangular slots
- Meatoplasty skin and graft interdigitate Minimizes risk of circumferential scar formation Circumferential scar contracts into stenosis Excess graft trimmed so there is no redundancy Neocanal tightly packed with Merocel strips to stent it
- Healed postoperative ear canal behind the auricular remnant
Postoperative care
- Discharge or overnight admission by preference and age Oral cephalexin and analgesia from day one Mastoid and skin graft dressings removed day one Antibiotic ointment over the postauricular incision Antibiotic-soaked cotton ball changed at the meatus daily
- Seen 1-2 weeks after surgery Sutures and all packing removed Silastic disc removed at the same visit Corticosteroid-antibiotic drops twice daily for 1 week Strict dry ear precautions; canal left open to air
- Second visit one month later Canal debrided of desquamated epithelium Skin graft should be dry and healthy beneath the crust First postoperative audiogram at this visit No restrictions after this visit
- Follow up every 6-12 months indefinitely Debridement of desquamated epithelial crust The skin graft is healthy but not self-cleaning Failure to clean: decreased hearing, chronic infection Swimming permitted with alcohol drops afterwards Alcohol drops also once a week
Complications and results
- 15-20%
- Most common complication, 15-20% of patients Usually requires revision surgery 58% of one revision series were for neocanal stenosis Careful meatoplasty lowers but does not remove the risk Younger children may have a higher rate
- Chronic drainage or infection in about 10% Usually skin graft slough with canal mucosalization Revision with a new skin graft may be needed Gentian violet may temporize a small area 19% of Oliver revisions were for refractory otorrhea 75% achieved a dry canal at over 3 months
- Rare but must be considered in a chronic draining ear May occur years after the primary surgery Keratin build-up under a sloughing graft is the mechanism Annual careful in-office debridement is preventive
- SNHL in about 5% of cases Mechanism: drill energy conducted through the chain Facial nerve injury reported at 0.1% Meta-analysis average 0.5%, range 0.0-5.0% Larger series quote under 1.5% Prevention: CT study, selection, technique, monitoring
- 15-20% lose the initial hearing gain Lateralization of the tympanic membrane is one cause Refixation of the ossicular chain is the other Counsel that 15-20% will need a revision procedure Revision for stenosis, hearing loss or graft slough
- Mechanisms of late hearing deterioration
- Better preoperative hearing predicts better results Preoperative SRT 50 dB or better: 66% normal after surgery Preoperative SRT above 60 dB: only 40% Series of 133 atretic ears Middle ear aeration is the key anatomic predictor
- Lambert: two-thirds kept SRT 30 dB or better beyond 1 year About one-third required a revision procedure De la Cruz: ABG 30 dB or less in 51% of primary cases Same series: 39% of revisions Digoy and Cueva: 50% achieved SRT 30 dB or better
- Imbery: PTA declined 8.2 dB over a mean of 4 years Only 64% had stable hearing at last follow-up Just over 20% declined 10-20 dB in air conduction PTA 15% declined by 20 dB or more Long-term follow-up is essential
- Digoy and Cueva: no difference between the two Ossiculoplasty group achieved 53% success Dobratz: significant advantage to the native chain Preserve the patient's own chain where possible Notched PORP where the joint is discontinuous
- Refixation from insufficient bony clearance around the chain Facial nerve proximity may force a compromise Low tegmen or bony exostoses can form during puberty Teufert: refixation fell from 25% to 3.8% Change: laser, thinner skin graft, Silastic, Merocel
- Chang: only 26% with a poor initial result benefited Oliver: 107 revisions, good results for lost hearing gains 58% for stenosis, 19% otorrhea, 20% conductive loss Most stenosis and drainage fixed after one revision SRT improved significantly over preoperative values
- Challenging operation with a real learning curve About 32 ears for good short-term hearing results About 48 ears for good long-term outcomes Anterior approach has withstood scrutiny Candidacy selection and technique remain critical
- Device comparisons do not capture sound localization Nor summation or hearing in noise Demonstrated after repair of unilateral atresia Subtle deficits of unilateral loss increasingly recognized Rehabilitation of unilateral atresia gaining acceptance
- Technically challenging reconstruction of canal and drum Success rests on preoperative patient selection And on meticulous technique at every step Middle ear aeration is the key anatomic requirement Restores natural sound conduction without a device Long-term cleaning and follow-up are obligatory
- Take-home points
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- Haynes-Glasscock-Shambaugh Surgery of the Ear, Seventh Edition
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