[Role of computed tomography in the preoperative diagnosis of otosclerosis]

Otosclerosis is an osteodystrophy of the otic capsule and presents with progressive conductive hearing loss. Imaging studies, especially computed tomography (CT) and cone-beam CT, have gained increased relevance in the diagnosis of otosclerosis.

This study investigated whether there is a correlation between the extent of otosclerosis in high-resolution or cone-beam CT and hearing loss in pure-tone audiometry.

Based on an existing classification of otosclerotic foci, a classification was established. Preoperative CT scans of patients undergoing stapedotomy between 2015 and 2019 were evaluated and classified by two independent otorhinolaryngologists. The preoperative pure-tone audiograms were analysed and compared to the results of CT.

A total of 168 CT studies (i.e., 168 ears) in 156 patients with intraoperatively confirmed otosclerosis were included in our study. A correlation between the extent of the otosclerotic focus or the calculated scores and hearing loss in pure-tone audiometry (air conduction, bone conduction and air-bone-gap) could not be proven.

Preoperative CT is not obligatory. However, preoperative imaging using CT or cone-beam CT can be helpful to confirm the diagnosis and exclude other middle or inner ear pathologies as well as in planning of the surgical procedure in the overall context of otoscopy and audiometry. A correlation with the degree of hearing impairment could not be demonstrated and remains unclear.