Impedance-based tracking of a cochlear implant electrode reliably detects successful array insertion.

INTRODUCTION: Continuous impedance measurements during cochlear implantation have been hypothesized to provide a reliable indication if the electrode is inside or outside the cochlea. Therefore they provide a valuable feedback mechanism for successful insertion to the surgeon. This study aims to investigate whether impedances can be used to reliably detect successful insertion of the cochlear -implant electrode array. METHODS: In a prospective cross-sectional single-center study patients undergoing cochlear implantation with flexible lateral wall arrays (MED-EL, Innsbruck, Austria) were recruited between June 2022 and May 2023. Continuous impedance telemetry during electrode array insertion was obtained and compared to the ground truth of visual and audiological feedback by the surgeon. RESULTS: 34 patients (23 women, 11 men;, 16 left ears, 18 right ears) with a mean age of 52.8 years (SD 19.6 years) were included. The present study found a reliability of 88.9% comparing the algorithm of continuous insertion to the ground truth. CONCLUSIONS: Continuous impedance measurements show a high reliability to detect the insertion of electrode contacts of a cochlear implant electrode array. The data collected by the software are suitable to detect misplacements already during insertion. This method is a promising approach to intraoperatively monitor successful insertion and offers the opportunity to replace fluoroscopy and radiological imaging in the aftercare of cochlear implant surgery.