aural atresia

Classification

• type 1
  • bony or fibrous atresia of the lateral part of the external auditory canal & an almost normal medial part & middle ear
• type 2
  • most frequent type
  • partial or total aplasia of the external auditory canal
• type 2A
  • external auditory canal with either complete bony atresia of the medial part or partial aplasia that ends blindly in a fistula leading to a rudimentary tympanic membrane
• type 2B
  • bony stenosis of the total length of the external auditory canal
• type 3
  • bony atresia of the external auditory canal & a very small or absent middle-ear cavity

Etiology

• idiopathic
• genetic

Epidemiology

rare

Pathology

• the external auditory canal & structures in the middle ear fail to develop completely
• varying degrees of severity
• in the extreme, no identifiable ear canal exists, & the middle ear & its structures may be absent
• may coexist with syndromes that feature 1st & 2nd branchial arch deformities
  • Treacher-Collins syndrome
  • hemifacial microsomia
  • Goldenhar syndrome

Genetics

• associated with defects in TSHZ1

Clinical manifestations

• unilateral or bilateral atresia
• some degree of failure of the development of the external auditory canal
• if bilateral, severity of the deformity may vary between the ears
• malformation can also involve the tympanic membrane, ossicles & middle ear space
• inner ear development is most often normal

Diagnostic procedures

• hearing evaluation
• auditory-evoked brainstem responses (bilateral)
  • assesses cochlear function

Management

• hearing rehablitation
• atresiaplasty versus Baha system (no consensus)

More general terms

• atresia (atretic, atresic, imperforate)
• genetic disease of the auditory system

Database

• OMIM: https://mirror.omim.org/entry/607842