Is routine preoperative computed tomography imaging justified in otosclerosis? A retrospective single-centre analysis

Objectives: The improvement in the quality of CT imaging in recent years has led to increasing use in the preoperative workup before primary stapedotomy. The aim of this study is to determine whether routine CT scanning is justified by analysing whether the detectability of otoclerotic foci in the CT imaging is associated with a different clinical picture or surgical outcome. Methods: Retrospective analysis of patient charts, CT data sets, preoperative and postoperative audiograms of 41 patients who underwent 47 primary stapedotomies. The preoperative and short-term postoperative audiometric thresholds were analysed at 0.5, 1, 2 and 4 kHz. Results: In 36 of 47 ears (76.5%), fenestral otosclerosis was observed in the CT scans. Among those 36 'CT-positive' ears, five ears (13.8%) showed additional signs of retrofenestral (cochlear) otosclerosis. The preoperative audiogram results showed no significant differences in the air conduction threshold, bone conduction threshold or air-bone gap between the CT-positive and CT-negative groups. The overall average preoperative air-bone gap (26.4 dB +/- 8.3 dB) improved to 12 dB (+/- 7.6 dB) postoperatively, without a significant difference between the CT-positive and CT-negative groups. Conclusion: The detectability of otosclerotic foci on CT scans did not correlate with the preoperative audiogram or the ability to close the air-bone gap postoperatively. The CT scans did not reveal new information that influenced the decision to operate or which side to operate. The findings do not support routine preoperative CT scanning in suspected otosclerosis cases. CT imaging may complement audiological tests in atypical cases. Even in straightforward cases, preoperative CT scanning may be offered to patients in order to guide the preoperative counselling. However, the patients should be made aware of the associated radiation risks.