La déhiscence du canal semi circulaire supérieur

Introduction : Superior semicircular canal dehiscence is a rare entity witch is recently described. The common symptom is pressure-induced vertigo. Patients and methods: we report 2 cases of superior semicircular canal dehiscence identified by computed tomography (CT) of the petrous bone in patients with mixed hearing loss and a normal tympanic membrane. Results: Superior semicircular canal dehiscence was bilateral in 1 patient. Mixed hearing loss with a normal tympanic membrane without vertigo was the presenting manifestation in all cases. Ultrahigh-resolution CT of the petrous bones with coronal and sagittal sections provided the diagnosis of superior semicircular canal dehiscence. Conclusion: Mixed hearing loss with a normal tympanic membrane should suggest superior semi circular canal dehiscence. Coronal and sagittal CT sections less than 1 mm in thickness establish the diagnosis.