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Congenital Malformations of the Pinna and Their Management

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1. Embryology

• 1st arch (Meckel's cartilage) hillocks (1, 2, 3): Traditionally said to form the tragus and helical root
• 2nd arch (Reichert's cartilage) hillocks (4, 5, 6): Form the bulk of the pinna (helix, antihelix, antitragus, lobule)
• The 1st branchial cleft persists as the external auditory meatus

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2. Classification of Congenital Pinna Malformations

A. By Severity - Weerda Classification (selected by Am J Med Genet for reporting)

B. Specific Types of Pinna Malformations

1. Microtia

• Spectrum of congenital malformations with varying degrees of underdevelopment of the auricle
• Anotia = most severe (complete absence)
• Incidence: 0.83 to 17.4 per 10,000 live births; overall prevalence ~1.69 per 10,000
• Demographics: Males > females (2.5:1); right side > left; unilateral in 77-93% of cases
• Higher prevalence in Hispanic (3.13/10,000) and Native American (4.67/10,000) populations
• At least 50% of cases occur as part of a sequence or syndrome (e.g., Treacher Collins, Goldenhar syndrome, hemifacial microsomia)

• Grade I: Ear fairly well formed but smaller than normal; most components recognizable
• Grade II: External ear ~half of normal size but reasonably good shape
• Grade III: Only a small nub of skin or small piece of cartilage remains ("peanut ear")

2. Protruding/Prominent Ear (Bat Ear)

• Auricular cartilage of appropriate size but lacks a well-defined antihelical fold
• Excessively high or spherical conchal cartilage may also contribute
• Helix-to-scalp distance: normal = 15-20 mm; abnormal if > 20 mm
• Normal auricular position (Tolleth guidelines):
  • ~1 ear-length posterior to the lateral orbital rim
  • Top of ear at the level of the brow
  • Inferior lobule at level of columellar base
  • Auricular axis rotated 15-20 degrees in the posterior direction
• No otologic ramifications; significance is psychological (teasing from peers)

3. Lop Ear / Cup Ear

• Helical rim folded downward and anteriorly (Grade II Weerda)

4. Cryptotia (Hidden Ear)

• Superior portion of auricle buried beneath temporal scalp

5. Constricted Ear

• Circumferential constriction limiting growth; includes cup ear deformity

6. Pre-auricular Tags and Sinuses

• Accessory auricular tissue from abnormal hillock development
• Preauricular sinus/cysts: result from incomplete fusion of hillocks; may require excision if recurrently infected

7. Anotia

• Complete absence of the auricle; most extreme form of microtia

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3. Associated Conditions

• Congenital aural atresia (CAA): Absent/stenotic EAC, often associated with Grade II-III microtia; incidence 1:20,000 live births
• Middle ear ossicular anomalies
• Syndromes: Treacher Collins, Goldenhar (hemifacial microsomia), Nager, branchio-oto-renal (BOR) syndrome
• Conductive hearing loss (CHL) from atresia; rarely sensorineural

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4. Evaluation

1. Clinical examination to rule out concomitant atresia or syndromic features
2. Age-appropriate hearing assessment:
   • Bone conduction ABR (auditory brainstem response) prior to 4 months of age - to avoid anaesthetic risks and capitalize on open sutures for ear-specific thresholds
   • Ongoing audiologic follow-up
3. Normal adult ear height: 5.5 to 6.5 cm; 95% of this is achieved by 8-10 years of age
4. CT temporal bone - for atresia assessment and surgical planning
5. Pre-natal counseling if microtia suspected on ultrasound

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5. Management

A. Prominent/Protruding Ear - Otoplasty

• Correct protrusion of helix and lobe
• Create antihelical fold
• Avoid overcorrection
• Create symmetric auricles in appearance and position

Mustarde Technique (Posterior Approach - preferred)

1. Preoperative markings - define crest of antihelix; mark suture sites with needle
2. Placement of marking sutures to confirm position
3. Elliptical incision in the postauricular sulcus
4. Posterior auricular skin elevated to helical rim and triangular fossa (avoid cartilage injury)
5. Tissues also elevated from conchal cartilage toward mastoid periosteum
6. Intrinsic and extrinsic muscles divided
7. Several Mustarde sutures (horizontal mattress sutures, 5-0 or 6-0 nonabsorbable with taper needle) placed through cartilage and anterior perichondrium to:
   • Roll and create smooth antihelical fold
   • Approximate scaphoid fossa closer to concha
8. Concha setback if needed (conchal bowl excision or mastoid suture)
9. Ellipse of postauricular skin resected and closed

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B. Microtia - Management Options

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C. Surgical Reconstruction of Microtia

1. Autologous Rib Cartilage Reconstruction

• 6-10 years of age depending on technique
• Brent technique: can begin at age 6-7 (requires less cartilage)
• Nagata technique: typically age 10 (requires chest circumference at xiphoid ≥60 cm, sufficient 8th rib length)
• Normal ear on contralateral side serves as template (X-ray film/laser scan)
• Framework position: ~7 cm from lateral orbital canthus to helical root; ~9 cm from oral commissure to lobule

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Brent's Four-Stage Technique

• Less 3D detail (no antihelical component)
• Atypical ear appearance after Stage 1 (lobule not yet transposed)
• Requires less rib cartilage - suitable from age 6-7

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Nagata's Two-Stage Technique (preferred by many centers)

• More 3D detail - includes antihelical feature, tragus, conchal bowl
• Normal ear appearance after Stage 1
• Requires more cartilage - delayed to age 10
• Firmin modification widely used

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2. Alloplastic Reconstruction (MedPor/SuPor)

1. Y-shaped incision with anteroposterior limb 10 cm superior to auricular remnant in temporal scalp
2. Skin flaps elevated; pocket created for implant
3. Implant measured, trimmed, positioned
4. Temporoparietal fascia (TPF) flap elevated and brought down to cover implant
5. Superior 1/3 of implant covered with full-thickness skin graft from contralateral postauricular area

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D. Management Algorithm - Grade-Based

• Rib graft approach: Microtia repair FIRST (virgin field needed), atresia repair 3-4 months later
• MedPor approach: Atresia repair FIRST (to avoid implant extrusion), then MedPor microtia repair
• In ~50% of cases, reconstructed auricle must be moved (usually posterosuperiorly) to align meatus with newly created bony canal

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E. Hearing Rehabilitation in Microtia with Atresia

• Unilateral atresia: No amplification required if contralateral ear normal (normal speech/language development)
• Bilateral atresia: Bone-conducting hearing device placed as soon as possible after birth (ABR testing mandatory)
• BAHA (Bone-Anchored Hearing Aid): FDA approved for age ≥6 years; can be implanted at Stage 2 of Nagata technique
• Conventional BTE/ITE hearing aid placed in newly epithelialized canal after atresiaplasty if hearing gain insufficient

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6. Complications of Microtia Repair

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7. Future Advances

• 3D printing of auricular frameworks (in preclinical testing)
• Tissue engineering with bioscaffolds as alternative to autologous rib or alloplastic reconstruction
• Quantification of costal cartilage stock preoperatively using 3D rib cage CT or ultrasound to avoid insufficient cartilage at surgery

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Summary Table for PG Exams

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