Imaging description

Superior semicircular canal dehiscence (SSCD) is a recently described entity that is characterized by vestibular symptoms elicited by sound or pressure. Minor was the first to associate this clinical phenomenon with an anatomical defect of the superior semicircular canal detected with high-resolution computed tomography (HRCT) [1]. When the bone over the canal becomes thin or dehiscent, it acts as an additional window for the vestibular system, thereby allowing pressure and noise changes to induce vestibular activity. Over the last decade, this entity has been increasingly diagnosed and treated, although it is still not entirely clear whether the bony defect is congenital or acquired.

The sound is normally transmitted via stapes through the oval window into the cochlea. The round window dissipates the pressure, transmitting it back into the middle ear. Under normal conditions, the pressure in the semicircular canal remains constant. In the presence of a dehiscent roof, the superior semicircular canal (SSC) acts as another window and allows transmission of pressure to the vestibular apparatus, resulting in vertigo.