Concept and first Implementation of an intracochlearly navigated Electrode Array for Cochlear Implantation

Abstract

Cochlear implants (CI) are an established treatment for people with deafness or severe hearing loss. To restore patients' hearing an electrode array (EA) of the CI is inserted into the cochlea to stimulate the auditory nerve. Thereby, the exact positioning and gentle insertion of the EA is crucial for optimal hearing perception outcome. Currently, only microscopic vision is available for entering the cochlea, but the critical intracochlear process during EA insertion is like a "black box" and the surgeon has to rely on haptic feedback. Methods for visualizing the insertion process during surgery are inaccurate or not suitable for routine use due to radiation exposure. To address this problem, we developed a computerassisted and image-guided cochlear implantation system with an exact real-time visualization of the EA position during the insertion process. The system is based on an electromagnetic tracking system that measures the position and orientation of a sensor integrated into the tip of a EA prototype and visualizes it in presurgical image data. A first experiment with our system showed that a EA prototype could be inserted into a cochlea of a human temporal bone and placed with an accuracy of 1.1 mm ± 0.4 mm. A maximum insertion angle of 120° was achieved.

Towards inferring positioning of straight cochlear‐implant electrode arrays during insertion using real‐time impedance sensing

“…For example, imaging feedback tools for analysis of CI placement include postoperative CT, 6 preoperative Magnetic Resonance Imaging to determine candidacy, 7 and real‐time fluoroscopy during surgery, 8 but these techniques are burdened by cost, patient radiation exposure, and/or lack of true real‐time visualisation 9 . Custom EAs have also been designed that incorporate strain gauges, 10 scanning electrochemical microscopy, 11 a fibre‐optic imaging probe, 12 or an electromagnetic sensor 13 for position sensing. Polymer optical fibre Bragg gratings have also recently been integrated into an experimental EA to detect forces and insertion trajectories 14 .…”