Ossicular chain disruption

Ossicular chain disruption (or ossicular discontinuity) is loss of normal alignment between the three middle ear ossicles. The condition is a cause of conductive hearing loss.

Exact incidence and prevalence are not known. Hearing loss associated with temporal bone fractures in children occurs in 75%, but persists beyond 1 month in less than 15%.

Sudden conductive hearing loss in traumatic cases. The hearing loss may be due to ossicular chain disruption or middle ear hemorrhage. Sensorineural hearing loss may coexist, e.g. in temporal bone fractures that have a transverse component.

Ancillary features include hemotympanum and/or otorrhea.

Causes are:

Loss of normal joint alignment: 

  • the incus and malleus are normally closely apposed, resembling a scoop of ice cream in a cone
    • the head of the malleus represents the ice cream
    • the body and short process of the incus represent the cone

3D reconstructions are useful for surgical planning.

Conductive hearing loss of more than 30 dB persisting for six months post injury is considered an indication for reconstruction of the ossicular chain:

  • conservative:
    • hearing aids
  • surgical (acute or delayed):
    • relocation: reconstruction with a hydroxyapatite prosthesis and/or cartilage allograft
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Article information

rID: 23289
Tag: trauma
Synonyms or Alternate Spellings:
  • Ossicular discontinuity
  • Disruption of the ossicular chain

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Cases and figures

  • Figure 1: with temporal bone fracture
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  • Case 1
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  • Case 2
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  • Case 3: incudo-mallear joint disruption
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  • Case 4
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  • Case 5: incudo-malleolar disruption
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