Sensitivity of High-Resolution Computed Tomography in Otosclerosis Patients undergoing Primary Stapedotomy

To determine the incidence of abnormal otospongiotic or otosclerotic findings on high-resolution computed tomography (HRCT) as read by local radiologists in patients with surgically-confirmed otosclerosis.

Retrospective chart review.

Tertiary-referral private otology-neurotology practice.

Adults (>18 years old) with surgically-confirmed otosclerosis between 2012 and 2017 with a HRCT performed preoperatively.

Preoperative HRCT then stapedotomy.

Positive identification and location of radiographic otosclerosis as reported by the local radiologist. We then correlated the CT with surgical location as documented at time of surgery. Audiometry, demographic data, intraoperative findings, and surgical technique were secondarily reviewed.

Of the 708 stapes surgeries were performed during the study time frame. Preoperative HRCT scans were available for 68 primary stapedotomy surgeries performed in 54 patients. Otosclerosis was reported in 20/68 (29.4%). Following a negative report by the local radiologist, a re-review by the surgeon and/or collaborating neuroradiologist confirmed otosclerosis in 12/48 additional cases (25.0%). There was an overall sensitivity of 47.1%. Intraoperatively, cases with negative reads tended to have more limited localization at the ligament (8.7%) or anterior crus (39.1%), compared with positive reads, which demonstrated more extensive involvement, with bipolar foci (30.0%) or diffuse footplate manifestations (20.0%) more common. Acoustic reflexes were characteristically absent.

While HRCT may aid in the diagnosis of otosclerosis and rule out concomitant pathology in certain cases of clinical uncertainty or unexplained symptoms, its sensitivity for otosclerosis remains low. HRCT should not be relied upon to diagnose routine fenestral otosclerosis.