The role of temporal bone computed tomography in the diagnosis and treatment planning of otosclerosis

Introduction Otosclerosis typically manifests with conductive or mixed hearing loss, as a result of bone changes in the oval window and otic capsule. The diagnosis and treatment indication are usually decided clinically. If the diagnosis is unclear, a temporal bone computed tomography (CT) can be performed preoperatively. The aim of this study is to evaluate the role of temporal bone CT in the in diagnosis and treatment planning of otosclerosis.

Methods Retrospective analysis of patient charts and CT data sets of 33 patients with clinical suspicion of otosclerosis. In all cases, a temporal bone CT was performed preoperatively, followed by an explorative tympanotomy. An otolaryngologist and a neuroradiologist analyzed the CT images with regard to the presence of otosclerotic foci.

Results In three patients, otosclerosis was ruled out intraoperatively. In these three patients, the CT scans did not show any otosclerotic foci. In 30 patients (35 ears), otosclerosis was confirmed intraoperatively. In 27 of 35 ears (77 %), otosclerotic foci were seen in the oval window or fissula ante fenestram (fenestral otosclerosis). Among those 27 ears, five ears (18 %) additionally showed signs of retrofenestral (cochlear) otosclerosis.

Conclusion Temporal bone CT showed a high sensitivity (77 %) and specificity (100 %) rate in the diagnosis of otosclerosis in this patient cohort. However, otosclerosis remains mainly a clinical diagnosis. CT imaging may complement the audiological tests, and help support the diagnosis in unclear or atypical cases. Furthermore, CT scanning may detect anatomical anomalies preoperatively.

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Publication History

Article published online:
10 June 2020