Superior semicircular canal dehiscence in patients with spontaneous cerebrospinal fluid otorrhea.

OBJECTIVE To determine the prevalence of superior semicircular canal dehiscence (SCD) in patients with spontaneous cerebrospinal fluid (CSF) otorrhea. STUDY DESIGN Case series with chart review. SETTING Tertiary care referral center. SUBJECTS AND METHODS Patients included have undergone a middle fossa craniotomy for repair of spontaneous CSF otorrhea between January 2007 and December 2011. The main outcome measure is the presence or absence of SCD observed during spontaneous CSF leak repair. Computed tomography (CT) imaging was also reviewed to determine the diagnostic accuracy of this modality. RESULTS Thirty-three ears in 31 patients underwent surgical repair for spontaneous CSF otorrhea via a middle fossa craniotomy. The average age at the time of repair was 60.5 years, and 80.6% of patients were female. A dehiscence of the superior canal was observed in 15.2% of ears (16.1% of individuals). No significant difference in age, body mass index, or sex was noted between those patients with or without a superior canal dehiscence. For the diagnosis of SCD, coronal CT was 100% sensitive and 91.7% specific. The positive predictive value and negative predictive value of CT were 66.7% and 100%, respectively. CONCLUSION The prevalence of superior semicircular canal dehiscence in ears with spontaneous otorrhea is 15.2%. This prevalence is greater than the 0.5% reported in a temporal bone study of ears not selected for CSF otorrhea.