Supralabyrinthine air cell is not present in superior semicircular canal dehiscence.

Objectives: Superior semicircular canal dehiscence (SSCD) is defined as a defect in the bone overly the superior semicircular canal (SSC). The purpose of this study is to evaluate the pre-operative imaging examinations of patients who have undergone SSCD repair. We hypothesize that these patients will not have a supralabyrinthine air cell on the side of surgery. Material and Methods: Our group retrospectively reviewed 50 consecutive pre-operative computed tomography (CT) temporal bone examinations who had confirmed SSCD on intraoperative examination and underwent repair for the presence of a supralabyrinthine air cell. Results: 100% of patients who had confirmed SSCD on intraoperative examination had no supralabyrinthine air cell on pre-operative CT of the temporal bone. Conclusion: This study shows that a supralabyrinthine air cell is not present in SSCD. When a supralabyrinthine air cell is present, the roof of the SSC is intact. CT and magnetic resonance imaging (MRI) are often performed together to evaluate for SSCD and exclude other etiologies. We propose that if a supralabyrinthine air cell is seen on MRI, no CT is necessary, thus avoiding unnecessary radiation exposure and additional imaging costs to the patient.