Superior Canal Dehiscence

Several theories have been proposed regarding the cause of SCD, including

  • embryological—a postnatal failure of bone formation over the superior semicircular canal due to a malpositioned primitive otocyst
  • bone thinning associated with aging and/or vascular malformations
  • head trauma, typically to the temporal bone
  • surgical complication following surgical removal of the bone over the superior canal, usually in an attempt to “blue line” the labyrinth
  • increased intracranial pressure resulting from activities such as straining, sneezing or coughing in already thinned bone

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