Short-Term Experience in Cochlear Implantation with Slim Modiolar Electrode Array (CI532): Comparison to Previous Devices

Abstract

Background and Objectives There have been no reports in Korea regarding cochlear implant surgeries using Cochlear Nucleus Profile Slim Modiolar electrode [CI532 (Cochlear Ltd.)], as it has been recently released in Korea. We aimed to investigate the short-term results of CI532 and compare them with previous devices with perimodiolar or straight electrodes arrays from the same manufacturer.Subjects and Method From August 2018 to July 2019, 52 patients (26 adults; 26 children) who underwent cochlear implantation of CI532 were included. The intraoperative impedance and evoked compound action potential (ECAP) threshold in each electrode were analyzed and compared with the devices with a perimodiolar electrode array [Contour Advance<sup>®</sup> (Cochlear Ltd.)] and a lateral wall electrode array [CI422 and CI522 (Cochlear Ltd.)]. Postoperative changes of hearing thresholds at each frequency (250, 500, and 1000 Hz) and aided word recognition scores (WRS) were also compared.Results CI532 showed significantly lower intraoperative impedance in the basal regions compared to the lateral wall electrode array. The ECAP thresholds of CI532 in the apical electrodes were significantly lower than that in the other two groups. After implantation, CI532 showed a significant preservation of hearing thresholds at most frequencies and showed significantly higher preservation rates than the other electrodes. However, there was no difference between the three groups regarding the postoperative short-term aided WRS.Conclusion CI532 showed lower intraoperative impedances and ECAP thresholds, and better short-term hearing preservation outcomes compared to the other electrodes, suggesting that CI532 electrode might be a better option with less traumatic insertion. However, there was no significant difference in the aided WRS, and further studies with a longer follow-up are necessary to examine the difference of audiologic outcomes.