Retrospective Evaluation of a Technique for Patient-Customized Placement of Precurved Cochlear Implant Electrode Arrays.

Objective Precurved electrode arrays (EAs) are commonly used in cochlear implants (CIs). Modiolar placement of such arrays has been shown to lead to better hearing outcomes. In this project, we retrospectively evaluated the modiolar positioning of EAs within a large CI imaging database. We aimed to discover the rate at which perimodiolar placement is successfully achieved and to evaluate a new technique we propose to preoperatively plan patient-customized EA insertion depths to improve perimodiolar placement at the time of surgery. Study Design Retrospective chart review and radiographic analysis. Setting Single tertiary academic referral center. Subjects and Methods Ninety-seven CI ears were evaluated. Perimodiolar positioning of electrodes was quantified using pre- and postimplantation computed tomography scans and automated image analysis techniques. Results Average perimodiolar distance was 0.59 ± 0.18 mm. Disagreement between the actual and our recommended insertion depth was found to be positively correlated with perimodiolar distance ( r = 0.49, P < .0001). Conclusions These results show that the average CI recipient with a precurved EA has a number of electrodes distant to the modiolus where they are not most effective. Our results also indicate the approach we propose for selecting patient-customized EA insertion depth would lead to better perimodiolar placement of precurved EAs.