COCHLEAR IMPLANTSOn the Intracochlear Location of Straight Electrode Arrays After Cochlear Implantation: How Lateral Are Lateral Wall Electrodes?Salcher, Rolf∗; Boruchov, Aaron∗; Timm, Max∗; Steffens, Melanie∗; Giesemann, Anja†; Lenarz, Thomas∗,‡; Warnecke, Athanasia∗,‡Author Information ∗Department of Otorhinolaryngology †Department of Neuroradiology, Hannover Medical School ‡Cluster of Excellence of the German Research Foundation (DFG; “Deutsche Forschungsgemeinschaft”) “Hearing4all2.0”, Hannover, Germany Address correspondence and reprint requests to Athanasia Warnecke, M.D., Hannover Medical School, Carl-Neuberg-Street 1, 30625 Hannover, Germany; E-mail: [email protected] R.S. and A.B. equally contributed to this work. This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy—EXC 2177/1—Project ID 390895286 (to T.L. and A.W.). A.W. and R.S. received travel grants to international conferences from the company MedEL, Austria. Patient data were used for analysis. Informed consent was obtained from the patients by admission allowing the use of their anonymized data for research purposes. The data used to support the findings of this study are available from the corresponding author upon request. T.L. and A.W. are principle investigators in the Cluster of Excellence “Hearing4All” and received funding from the German Research Foundation. The authors disclose no conflicts of interest. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (http://journals.lww.com/otology-neurotology). Otology & Neurotology: February 2021 - Volume 42 - Issue 2 - p 242-250 doi: 10.1097/MAO.0000000000002880 Buy SDC Metrics Abstract Objective: Cochlear implants are the gold standard for patients with severe sensorineural hearing loss. A focused electrical stimulation of individual spiral ganglion neurons has not been achieved yet because the scala tympani is a fluid-filled compartment and does not offer a matrix for neuritic outgrowth. Coating of the electrode contacts with swelling hydrogels could fill that gap between the electrode array and the medial wall of the cochlea. Therefore, the exact position of the electrode array within the scala tympani has to be known. Study Design: Retrospective analysis of patient data sets. Setting: Tertiary referral center. A total of 95 patients with cochlear implants from one manufacturer were included in this study. The lateral wall, the modiolar wall, and the cochlear implant electrode were segmented using OsiriX MD. For repositioning and reconstructing the respective contours and measuring distances, files were analyzed in MATLAB. The distances from the edge of each electrode contact to the cochlear walls showed no significant differences. But between the different contacts within each patient, there were significant differences. Around 180 degree insertion, electrodes start to get in contact with the lateral wall. The tip of the electrode array was always facing toward the modiolar wall independent of the length of the electrode. We established a method to analyze the position of electrodes within the cochlea. © 2020, Otology & Neurotology, Inc.