Evaluating the Stapes as a Landmark for Round Window Identification in Cochlear Implantation

OBJECTIVE: To better understand the distance relationship of the stapes to the round window, to assist in intraoperative round window identification. STUDY DESIGN: Retrospective review of CT temporal bone imaging and multiplanar image reformat analysis. SETTING: Tertiary referral center. PATIENTS: Patients above 18 years of age who underwent cochlear implantation between January 2020 and April 2025 and had preoperative computed tomography (CT) imaging of the temporal bone. Patients were excluded if they had prior surgical procedures that could distort the stapes superstructure (eg, stapedectomy) or if image quality/resolution precluded adequate visualization of the stapes crus. INTERVENTION: None. MAIN OUTCOME MEASURE: Prediction accuracy of the stapes intercrural width to locate the level of the round window. RESULTS: There were 102 ears that were studied, including 51 (50%) left and 51 (50%) right ears. The average measured intercrural width was 2.1 mm (SD: 0.17 mm). The maximum intercrural distance was found to be 2.6 mm, and the minimum distance was 1.7 mm. In all 102 (100%) ears, the intercrural distance of the stapes accurately predicted the level of the RW on image analysis. CONCLUSION: The stapes intercrural width can be utilized as an accurate predictor of the round window level and is a simple and intuitive intraoperative tool surgeons can utilize to safely gain access to the cochlea.