Shape-Adaptive Cochlear Implant Electrode Arrays

Project Summary/Abstract During this Phase I SBIR effort, we will assess the viability of shape-adaptive cochlear implant (CI) electrode arrays as a new solution for achieving atraumatic cochlear implantation and optimal electrode positioning at the same time. Lateral wall electrodes have historically been the preferred CI electrode option due to the higher likelihood of achieving atraumatic insertion and preserving residual hearing. However, placing electrodes closer to the modiolus of the cochlea can offer potential performance benefits, such as more focal stimulation and reduced current spread, due to shorter distance from the electrode to the spiral ganglion neuron target. Unfortunately, conventional perimodiolar electrodes suffer from higher rates of trauma and electrode displacement (translocation), negatively affecting the preservation of residual hearing. Here, we are addressing this long-standing challenge by utilizing shape-memory polymers (SMP) as a dynamic element that induces programmed self-curling of the CI electrode arrays in the inner ear. This approach facilitates gentle and gradual repositioning of the implanted arrays from the lateral wall to the modiolar wall without trauma. By combining the advantages of both lateral wall electrodes (i.e., atraumatic insertion) and perimodiolar electrodes (i.e., focal placement), the proposed technology enables reliable cochlear implantation and optimal electrode placement at the same time, which is difficult to achieve with the current clinical CIs. Our effort encompasses fabrication of SMP-inlaid, self-curling CI arrays, assessment of their implantation profiles in a model cochlea as well as human temporal bones, and evaluation of insertion trauma by a histological evaluation. We will rigorously validate our approach through mechanical and surgical analyses including dynamic mechanical analysis and quantitative assessments of the insertion profiles based on macroscopic and microscopic imaging.