Congenital Aural Atresia

Congenital Aural Atresia

Congenital Aural Atresia

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Introduction & Embryology - Ear Canal Enigma

  • Congenital Aural Atresia (CAA): Defined as the failure of External Auditory Meatus (EAM) development, resulting in an absent or significantly narrowed ear canal.
  • Embryology:
    • Stems from abnormal development of the 1st & 2nd branchial arches and the 1st pharyngeal cleft (which forms the EAM from the 1st branchial groove).
  • Incidence: Occurs in approximately 1 in 10,000 to 1 in 20,000 live births.
  • Laterality:
    • Unilateral is more frequent.
    • Bilateral cases also occur.

⭐ Unilateral CAA is notably more common on the right side. EAC embryological development

Classification & Syndromes - Atresia Array

  • Jahrsdoerfer Score (/10): Assesses surgical candidacy. ≥7/10 = good prognosis.
    • Criteria: Stapes (2 pts), Oval window, Round window, Middle ear space, Facial nerve, Malleus-incus complex, Mastoid pneumatization, External ear. (📌 Sailors Often Review Maps For Many Months Eagerly)
  • Schuknecht Classification:
    • Type A: Lateral EAC atresia; TM/ossicles often normal.
    • Type B: Partial EAC atresia; ossicular issues.
    • Type C: Complete EAC atresia; TM absent, ossicular malformed.
    • Type D: Severe atresia; hypoplastic ME.
  • Associated Syndromes:
    • Treacher Collins (most common), Goldenhar (OAVS), Crouzon, Pierre Robin Sequence, BOR.

⭐ Treacher Collins Syndrome is the most common syndromic association with CAA. Jahrsdoerfer Score for Aural Atresiaoka

Clinical Features & Diagnosis - Silent Signals

  • Presentation:
    • Microtia (Grades I-IV): External ear deformity.
    • Absent EAM (External Auditory Meatus).
    • Conductive Hearing Loss (CHL): 50-70 dB.
  • Associated Anomalies:
    • Middle ear: Ossicular malformations, stapes fixation.
    • Facial nerve: Aberrant course common.
    • Inner ear: Less common, but check for cochlear anomalies.
  • Diagnostic Workup:
-   HRCT Timing: Age **4-5 years** for surgical candidates.
> ⭐ HRCT of the temporal bone is indispensable for surgical planning and assessing candidacy for atresiaplasty.

HRCT axial congenital aural atresia

Audiological Evaluation - Sounding Depths

  • Goal: Assess CHL severity, rule out SNHL, determine cochlear function.
  • Neonatal Screening: Otoacoustic Emissions (OAE), Automated Auditory Brainstem Response (AABR).
  • Age-dependent Audiometry:
    • Behavioral Observation Audiometry (BOA)
    • Visual Reinforcement Audiometry (VRA)
    • Conditioned Play Audiometry (CPA)
  • Auditory Brainstem Response (ABR): Essential for infants, bilateral cases, assessing cochlear nerve function. Air and bone conduction ABR.
  • Bone Conduction (BC) Testing: Critical to confirm normal cochlear reserve.
  • Immittance Audiometry: Tympanometry (usually flat/Type B), acoustic reflexes.

⭐ Bone conduction ABR is crucial to confirm normal cochlear function before considering surgical intervention for CAA.

Management - Opening Pathways

  • Team Approach: ENT surgeon, audiologist, speech therapist, geneticist, plastic surgeon.
  • Timing of Intervention:
    • Bilateral CAA: Early amplification (BCHA), surgery around 4-7 years.
    • Unilateral CAA: Controversial; often later or no surgery. Monitor speech/language.
  • Non-Surgical: Bone Conduction Hearing Aids (BCHA) vital for bilateral cases.

    ⭐ For bilateral CAA, early auditory rehabilitation with bone conduction hearing aids is critical for speech and language development, typically initiated within the first few months of life.

  • Surgical (Atresiaplasty/Canalplasty): Create EAM, tympanoplasty. Indications: Jahrsdoerfer score, patient choice. Contra: poor score.
    • Complications: Canal stenosis (most common), facial nerve injury, SNHL.
  • Auricular Reconstruction (Microtia Repair): Staged, often with atresiaplasty.

Examples of congenital aural atresia

High‑Yield Points - ⚡ Biggest Takeaways

  • Congenital Aural Atresia: Absence/underdevelopment of the EAC, often with microtia.
  • Results in conductive hearing loss (typically 40-60 dB); inner ear usually normal.
  • Unilateral more common; bilateral cases require early hearing aids (3-6 months).
  • HRCT temporal bone is crucial for surgical planning; Jahrsdoerfer grading assesses candidacy.
  • Surgical repair (atresiaplasty) usually deferred until age 5-7 years.
  • Key surgical risk: Anomalous facial nerve course.
  • Associated syndromes: Treacher Collins, Goldenhar.

Practice Questions: Congenital Aural Atresia

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In which condition do symptoms improve with crying?

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Flashcards: Congenital Aural Atresia

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_____lateral conductive type of hearing loss is seen in otosclerosis

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_____lateral conductive type of hearing loss is seen in otosclerosis

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