Pediatric Semicircular Canal Dehiscence: Radiographic and Histologic Prevalence, With Clinical Correlation.

OBJECTIVES To determine the prevalence of radiographic and histologic superior semicircular canal dehiscence (SSCD) and posterior semicircular canal dehiscence (PSCD) and associated changes in temporal bone thickness in children aged 0 to 7 years. STUDY DESIGN Retrospective chart review and histopathologic review of cadaveric bone specimens. SETTING Two tertiary referral centers. PATIENTS Children younger than 7 years who underwent high-resolution computed tomography scan including the temporal bones between 1998 and 2013 and temporal bones harvested from children younger than 7 years. INTERVENTION(S) Two hundred twenty-eight computed tomography studies and 58 temporal bone specimens were reviewed. Available patient demographics were tabulated. MAIN OUTCOME MEASURE(S) Prevalence of SSCD and PSCD and bone thickness over semicircular canals, with comparison across age groups. Clinical data were extracted for patients with radiographic dehiscence. RESULTS Prevalence by ear of SSCD was 11.9%, 4.9%, 2.8%, and 0% and of PSCD was 16.7%, 2.4%, 1.4%, and 0% in children aged less than 6 months, 6 to 11 months, 12 to 35 months, and 3 to 7 years, respectively. SSCD was statistically more common before 1 year of age and PSCD before 6 months of age. Bone thickness overlying both the SSC and the PSC increased with age. Radiographic PSC bone was significantly thicker than SSC bone in patients older than 12 months. No dehiscences were found in the histologic specimens. CONCLUSION Radiographic dehiscence of the canals is common in the first 6 months of life, with thin bone seen histologically. Prevalence decreases with increasing age as the bone overlying the canals increases in thickness.