Design of an Intra-Operative Imaging System for the Cochlear Implant

Research has shown that closer proximity of a cochlear implant electrode array to the inner modiolar wall can improve hearing performance in a recipient. It is understood that developing a real-time intra-operative imaging technique would bring the surgeon visual feedback that can correlate with tactile resistances during electrode insertion, reducing various risks of insertion traumas, while guiding the electrode for optimal placement. This paper presents the design of a 3-dimensional magnetic imaging system which provides a means for real-time imaging by reconstructing uniform segments of the electrode array's contours. In addition, the theoretical error of this reconstruction method is evaluated to select an optimal number of sensors within the electrode design. The theoretical error of the reconstruction method is evaluated for 7 to 22 inductive sensors within the electrode design. For 16 or more sensors, the error is improves to less than 0.5%. A working prototype was confirmed on a 10:1 scale with orthogonal Helmholtz coils at 85-115kHz.