MDCT of Dehiscent or Thin Bone Coverage over the Superior Semicircular Canal: Assessment of Prevalence by Age and Contralateral Canal Bone Thickness

Abstract

Objective: Superior semicircular canal dehiscence (SSCD) describes the presence of a defect in the superior bone coverage of the membranous SSC. The etiology of the defect is not known and its reported CT prevalence is variable. This study primarily aimed to report MDCT prevalences of SSCD and thin bone coverage over SSC among different age groups. A secondary aim was to assess for any association between SSCD and the thickness of contralateral bone coverage over SSC. Materials and Methods: Temporal bone MDCTs were retrospectively evaluated for SSCD and the thickness bone coverage over SSC. The prevalences of SSCD and thin bone coverage over SSC among different age groups, and the thickness of bone over SCC in SSCD and non-SSCD subjects were analyzed. Results: 509 subjects were included in the study. Age-adjusted models did not demonstrate a significant association between the age groups and the prevalence of SSCD (p=0.63) or between the age groups and the prevalence of thin bone coverage over SSC (p=0,81). Unilateral SSC roof thickness of ≤ 0.5 mm was significantly associated with increased prevalence of contralateral SSCD (p=0.05 and p=0.04). In subjects without radiological evidence of SSCD, right-or left-sided thin bone coverage over SSC was significantly associated with contralateral thin bone coverage (p