Preoperative and intraoperative evaluation of round window configuration during cochlear implant in children

Context: To establish a reliable factor for predicting the anticipated difficulty and adequacy of niche drilling without damaging the intracochlear structures during cochlear implant (CI) surgery. Aims: This study aimed to access the correlation of the distance from round window-to-vertical facial canal and round window to pyramid with the visibility of round window intraoperatively. Settings and Design: A prospective observational study of CI surgeries was conducted in the E.N.T. Department of Indira Gandhi Institute of Medical Sciences, Patna, from December 2019 to December 2021. The study included 30 children aged <5 years who presented to the E.N.T. OPD with prelingual deafness and were diagnosed with bilateral severe-to-profound hearing loss. Subjects and Methods: The preoperative high-resolution computed tomography images in the axial cut bone window setting at round window level were used to calculate the distance of round window-to-vertical facial canal and round window to pyramid on the RadiAnt DICOM Viewer. The intraoperative visibility was assessed through the recordings of the operation. Statistical Analysis Used: The data were analyzed using the MS Office 2019 Excel spreadsheet (Microsoft Corp., Redmond, WA, USA) and the program IBM SPSS 28.0.0 (SPSS Inc., Chicago, IL, USA). One-way analysis of variance was used. Results: A significant difference existed between round window and vertical facial canal distance measured preoperatively with the three categories of visibility of round window intraoperatively (P = 0.033), but a weak significant difference was found with the distance of round window to the pyramid with the visibility of round window (P > 0.05). Conclusions: Preoperative computed tomography measurement of the round window and vertical facial canal is a reliable predictor of a round window configuration that may aid in predicting the round window visibility.