A New Intraoperative Method for Controlling Electrode Placement in Cochlear Implant Surgeries: Nucleus® SmartNav System and Preliminary Results

Objective: This study aimed to evaluate electrode placement in the cochlea by analyzing data from the Nucleus SmartNav system.Methods: Cochlear implant (CI) surgery was retrospectively reviewed.The participants including the use of CI522 Slim Straight electrodes with anatomically normal inner ear structures were selected.Intra-operative (Intra-op) and post-operative direct graphy (X-ray imaging) results were compared to assess electrode placement in the cochlea.Results: A total of 15 ears (4 bilateral, 7 unilateral) were evaluated.The average age of the pediatric group was 38 months (6 participants), and the average age of the adult group was 39.8 years.Intra-op SmartNav measurements obtained an average angular insertion depth of 413.8670.9degrees (254-480), a mean insertion time of 89.6s47.05(40-173s), and an average insertion speed of 0.650.54mm/s (0.1-1.17 mm/s).In the initial placement check performed with the SmartNav system, the electrodes were placed in the appropriate position in 14 cases, and only one case had a tip fold-over (TFO).The electrode was reinserted, and a second check using the SmartNav system confirmed that TFO was not present.The SmartNav system demonstrated 100% sensitivity in determining the placement of the CI522 Slim Straight electrodes in all cases compared with direct X-ray results. Conclusion:In cases with anatomically normal inner ear structures, the SmartNav system was determined to be an effective and reliable method for Intra-op assessment of CI electrode placement, thereby reducing the need for additional Intra-op radiological imaging.