Exploring Trauma Patterns and Contributing Factors With Slim Straight Electrode Array After Cochlear Implantation

ObjectiveTo assess trauma patterns associated with the insertion of lateral wall electrode arrays. The study focused on 3 categories-scala tympani (ST), intermediate, and scala vestibuli (SV)-to identify traumatic patterns and contributing factors.Study DesignRetrospective study.SettingData from 106 cochlear implant recipients at a tertiary otologic center.MethodsDemographic and surgical data were collected from recipients who underwent cochlear implantation manually and with RobOtol (R). Measurements included cochlear dimensions, angular depth of insertion, and position of the first electrode. Three-dimensional reconstructions were used to analyze the electrode array location relative to the basilar membrane, categorized into ST, intermediate, and SV electrodes. Nontraumatic insertion was defined as all electrodes in the ST, while traumatic insertions had 1 or more electrodes in intermediate or SV locations.ResultsOut of 106 cases, 44% had nontraumatic and 56% had traumatic insertions. Demographic and surgical characteristics showed no association with traumatic insertions. A deeper position of the first electrode, relative to the round window, was associated with traumatic insertions (P = .03). Three trauma patterns were observed: distal (facing the apical electrodes), proximal (facing the middle electrodes around 180 degrees), and distal/proximal.ConclusionThis study considers the intermediate position which could be associated with basilar membrane lesions. Risk zones for intracochlear trauma with lateral wall arrays were identified distally and proximally. Traumatic insertions were independently linked to deeper array placement. Future studies should explore whether gentler insertion, without insisting on further electrode array insertion depth, could reduce the trauma during cochlear implantation.