Scan for Success? Number Needed to Scan and Management Changes in Preoperative Otosclerosis: Quantitative Analysis

OBJECTIVE: To quantify the cumulative number of images needed to scan (NNS) with preoperative high-resolution temporal bone computed tomography (HR-TBCT) to yield a change in management in patients undergoing primary stapes surgery for otosclerosis-related hearing loss. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary academic referral center. METHODS: Medical records of all patients referred for primary stapes surgery between 2010 and 2025 were reviewed. All patients suspected of otosclerosis routinely underwent preoperative HR-TBCT scan, and their CT findings were compared to the intraoperative findings of those who underwent surgery. All findings that altered informed consent, surgical candidacy, or surgical approach were recorded. The cumulative and temporal bone-specific condition NNS were calculated. RESULTS: ears). Prevalence of temporal bone conditions that alter management of stapes surgery included third window lesions (5.8%), lateral ossicular chain fixation (4.1%), overhanging facial nerve (1.3%), obliterative otosclerosis (1.0%), far-advanced otosclerosis (1.0%), and persistent stapedial artery (0.6%). The cumulative NNS for at least one management change, confirmed intraoperatively, was 38 (95% confidence interval 77-22). CONCLUSION: Routine preoperative HR-TBCT identifies clinically significant temporal bone pathology that alters management in approximately 14% of stapes surgery candidates. The NNS for intraoperatively confirmed findings was 38. HR-TBCT facilitates more accurate patient selection, improves informed consent, and reduces intraoperative complications. Incorporating HR-TBCT into the preoperative assessment enables comprehensive presurgical counseling and planning.