Preoperative Assessment Using CT and MRI Scans of the Temporal Bone to Determine the Degree of Difficulty in Cochlear Implant Surgery

Background Cochlear implant surgery is a complex procedure influenced by the anatomical structures of the temporal bone. Preoperative imaging using CT and MRI can provide critical insights into the surgical challenges that may be encountered. This study aims to evaluate the role of CT and MRI in preoperative assessment to predict the difficulty of cochlear implant surgery in terms of surgical time. Materials and methods A retrospective observational study was conducted at Saveetha Medical College and Hospital, Chennai, from April 2022 to September 2023. Ninety patients with severe to profound sensorineural hearing loss who underwent cochlear implantation were included. Preoperative high-resolution CT (HRCT) and MRI of the temporal bone were performed to assess various anatomical parameters. Surgical difficulty was evaluated intraoperatively and correlated with preoperative imaging findings. Data were analyzed using IBM SPSS Statistics for Windows, V. 21.0 (IBM Corp., Armonk, NY). Results The mean age of participants was 7.4±10.9 years, with the majority (66.7%) in the 1-5-year age group. Out of 90 participants, 50 were male and 40 were female. HRCT and MRI revealed that 35.6% of participants had hypo-/non-pneumatized mastoids, 3.3% had narrow facial recesses, and 3.3% had high-riding jugular bulbs. Significant correlations were found between surgical time and associated congenital (p=0.006) and acquired (p=0.0001) anomalies of the temporal bone, as well as the total difficulty score (p=0.0001). The mean surgical time was 103.97±25.2 minutes, with a range from 45 to 220 minutes. Conclusion Preoperative HRCT and MRI are valuable tools in predicting the degree of difficulty in cochlear implant surgery. Specific anatomical features identified in imaging studies can significantly influence the surgical approach and duration. These findings underscore the importance of detailed preoperative imaging to enhance surgical planning and outcomes in cochlear implant procedures.