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Objective: The aim of this study was to determine optimal radiological parameters for assessment of the round window approach in cochlear implantation surgery., Materials and Methods: Patients undergoing cochlear implantation at the Department of Otolaryngology in Szczecin, between 2015 and 2022 inclusive, were eligible for the study. Radiological assessments were performed according to eight parameters (seven proposed in the literature) and visibility clinical assessments were made intra-operatively on a scale of 1 to 5 (1 - not visible, 5 - fully visible). Visibility assessments of the round window niche (RWN) and round window membrane (RWM) allowed the difference (RWN minus RWM) to be used as a clinical assessment of the size of the overhang over the round window., Results: Computed tomography images of 57 ears from 52 patients were analyzed in terms of round window access. The study group included 26 females and 26 males, ranging in age from 1 year to 80 years, with a median age of 41 years. In clinical assessment, round window visibility was rated as 5, after removal of the bone overhang, in 69% of patients. Cochlear access through the round window was achieved in 39 (68%) cases, extended access through the round window in 13 (23%) cases and cochleostomy was performed in 5 (9%) cases. Statistically significant ordinal correlations with round-window access were found using one parameter from the literature (Chen_Angle) and from our proposal (RWM_prediction). From parameters describing the bone overhang of the round window, positive correlations (using Kendall rank tests) were found using parameters from the literature (Sarafraz_OH and Mehanna_OH)., Conclusions: Radiological measurements describing access to the round window which determine the angle based on the anatomy of the posterior wall of the auditory canal and the position of the facial nerve were found to be of the highest value., Clinical Relevance Statement: In the future, the use of algorithms for computed tomography evaluation and robot-assisted surgery will require parameters for assessing round window access, for surgery planning and choice of electrode. The parameters proposed by various authors are summarized, allowing researchers to assess their usefulness in further clinical practice., (© 2024. The Author(s).)

Background: The primary objective of this study was to analyse middle ear structures critical for cochlear implantation using computed tomography., Materials and Methods: Patients who underwent cochlear implantation at the Department of Otolaryngology in Szczecin between 2015 and 2022 were eligible for the study. We analysed computed tomography images of 57 ears in 52 patients. The following parameters were assessed: mastoid aeration, tegmen tympani height, sigmoid sinus position, posterior tympanotomy width, the distance between the facial nerve and chorda tympani, modified facial recess distance, and the prediction line described by other authors., Results: In 69% of patients, after the removal of the round window bony overhang, the round window membrane became fully visible. There were no statistically significant correlations found for parameters describing mastoid process anatomy or those rating the width of the posterior tympanotomy concerning round window access. The prediction lines, according to Kashio and Jwair, were found to be relevant. In cases where patients' access to the niche and membrane of the window was rated as good or very good during clinical evaluation, they were more likely to describe the window as being located posteriorly or medially in the radiological evaluation. Using a binary Jwair scale provided a better correlation with the clinical assessment. In cases where the windows were graded as posterior, the clinical assessment indicated better surgical access, especially to the RWM (Round Window Membrane)., Conclusions: Evaluating middle ear anatomy on a computed tomography scan is useful for preparing for middle ear surgery but does not significantly affect the ability to access the round window. For such access, the position of the window in relation to the facial nerve is the most relevant factor, and measurements based on this relationship hold the highest clinical value.