The International Tinnitus Journal

Computed Tomography-Based Workup of Conductive Hearing Loss with Normal Middle Ear: Don't Forget Superior Semicircular Canal Dehiscence

Author(s): Christian B. Teszler; Mary Daval; Khaled Altabaa; Marc T. Williams; Denis Ayache

Patients with superior semicircular canal dehiscence (SSCD) may have conductive hearing loss (CHL) with normal middle ear (ME). A patient with CHL and normal tympanic membrane at otoscopy underwent tympanotomy for presumed otosclerosis but had negative intraoperative findings. A high-resolution computed tomography (CT) scan of the temporal bone performed a few years later showed the absence of middle-ear disorder (especially the absence of imaging signs of otosclerosis) and revealed a bony dehiscence of the superior semicircular canal. High-resolution CT scan is the test of choice for diagnosing SSCD; it mimics otosclerosis by manifesting itself as CHL with a normal ME. The aim of this study is to remind radiologists and otolaryngologists that SSCD should be systematically considered among the etiologies of CHL with normal ME.

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