Semicircular canal dehiscence in HR multislice computed tomography: distribution, frequency, and clinical relevance

Eur Arch Otorhinolaryngol. 2012 Feb;269(2):475-80. doi: 10.1007/s00405-011-1688-6. Epub 2011 Jul 8.


The literature about bony defects in the semicircular canal system is highly inconsistent. Therefore, we analyzed a series of 700 high-resolution multislice CT examinations of the temporal bone for semicircular canal dehiscencies. An unselected group of ENT patients with different clinical symptoms and variable age was chosen. We found semicircular canal dehiscence in 9.6% of temporal bones, superior semicircular canal was affected mostly (8%), less common posterior semicircular canal (1.2%); only in 3 cases (0.4%), lateral semicircular canal showed dehiscence. In 60% of SSC dehiscence, we registered bilateral manifestation. The so-called "third mobile window" in semicircular canal dehiscence causes a great variety of clinical symptoms like vertigo, nystagmus, oscillopsies, hearing loss, tinnitus and autophonia. Comparison with anatomic studies shows that CT examination implies the risk of considerable overestimation; this fact emphasizes the important role of clinical and neurophysiological testing.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Child
  • Child, Preschool
  • Cholesteatoma, Middle Ear / complications
  • Cholesteatoma, Middle Ear / diagnostic imaging
  • Cholesteatoma, Middle Ear / epidemiology
  • Cross-Sectional Studies
  • Humans
  • Infant
  • Labyrinth Diseases / diagnostic imaging*
  • Labyrinth Diseases / epidemiology
  • Labyrinthitis / complications
  • Labyrinthitis / diagnostic imaging
  • Labyrinthitis / epidemiology
  • Meniere Disease / diagnostic imaging*
  • Meniere Disease / epidemiology
  • Middle Aged
  • Multidetector Computed Tomography*
  • Risk Factors
  • Semicircular Canals / diagnostic imaging*
  • Semicircular Canals / injuries
  • Temporal Bone / diagnostic imaging*
  • Temporal Bone / injuries
  • Young Adult