External auditory canal atresia

External auditory canal atresia (EACA) is characterized by complete or incomplete bony atresia of the external auditory canal (EAC) and, especially when seen in the setting of an associated syndrome, a dysplastic auricle and an abnormal middle ear cavity.

The incidence is 1 in 10,000-20,000 births 2.

Abnormal appearance of the external ear and conductive hearing loss present from birth.

Bilateral involvement is seen in approximately one-third of patients 2. The external auditory canal may be completely absent or incompletely atretic with further narrowing contributed to by soft tissue bands.

Findings in the middle ear are variable. The inner ear and inner auditory canal are typically normal (due to forming earlier in gestation). 

EAC atresia may be complicated by congenital cholesteatoma formation behind the atresia plate or in the middle ear.

Although frequently isolated (in which case the abnormality is less severe and isolated to the EAC) a number of syndromes are associated with external auditory canal atresia 2:

High resolution bony CT reformats is the modality of choice for assessing the external acoustic canal. A number or key points should be looked for and specifically mentioned in reports as it impacts on surgical reconstruction.

  • middle ear cavity volume: a width of greater than 3 mm is usually needed for successful surgery
  • ossicles 2
    • malleus: usually has a rudimentary handle (as there is no normal tympanic membrane)
    • incudomalleolar joint: usually normal
    • incus: usually normal
    • stapes: important to note as an abnormal or absent stapes needs to be replaced with a prosthetic
  • inner ear structure
    • both the oval and round window need to be present for successful surgery
  • course of internal carotid artery, and location of the jugular bulb: if abnormal can be hazardous during surgery
  • course of facial nerve: often abnormally anterior and can be damaged during reconstruction

Surgical reconstruction requires formation of a new EAC and new tympanic membrane (usually with temporalis fascia). The ossicles often need to be mobilized.

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Article information

rID: 1305
Synonyms or Alternate Spellings:
  • External auditory canal atresia (EACA)
  • EAC atresia
  • Atreseia of the external auditory canal
  • Atreseia of external auditory canal

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Cases and figures

  • Left EAC atresia
    Case 2: left (axial)
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  • Left EAC atresia
    Case 2: left (coronal)
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  • External Auditory...
    Case 3
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  • Case 4: right
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  • Case 5: right
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  • Case 6
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