[Evaluation of superior semicircular canal dehiscence in patients with vertigo and tinnitus].

OBJECTIVES: The aim of the study was to investigate the presence of superior semicircular canal dehiscence (SSC) in patients with unknown etilogy of vertigo/tinnitus. PATIENTS AND METHODS: This study was performed prospectively between December 2007 and March 2008. Fifty five patients (23 males, 32 females; mean age 44.5; range 36 to 74 year) with complaints of vertigo and/or tinnitus, of which we couldn,t establish the etiologies, were included in the study. Control group was consisted of 15 patients who didn,t have complaints of vertigo and/or tinnitus. A high resolution temporal bone computed tomograpy (CT) scan (1 mm slice thickness) was performed in all study groups (patients and controls). RESULTS: Thirty nine subjects (72%) had normal odiometric findings. Mild conductive hearing loss was present in 12 (22%) subjects. Two (3%) of the patients had moderate conductive hearing loss and the other two subjects (3%) had mixed type hearing loss. High resolution temporal bone CT scan revealed that 35 (65%) subjects had dehissence around SSC otic capsule whereas 20 (35%) remaining patients yielded no dehissence. Twenty one of 35 patients (60%) with dehissence at SSC had minimum defect and 14 patients (40%) had significant defect. Bilateral defect was present in nine (64%) of 14 patients with significant defect but none of the subjects with minimum defect showed bilateral involvement. None of the control subjects exhibited SSC dehissence with CT imaging. CONCLUSION: Semicircular canal dehissence was found in 65% of the patients with unknown etiology of the vertigo and tinnitus. Physicians should evaluate the SSC dehissence in patients with vertigo and tinnitus as an etiologic factor.