High-Precision Insertion Force Measurements for Cochlear Implant Surgery: Accuracy Analysis of an Improved Device

Abstract

Introduction: Insertion force measurement in cochlear implant surgery aims to improve hearing outcomes by detecting events during implantation that may lead to intracochlear trauma. Our group recently developed the Forception Tool, which enabled the first intraoperative insertion force measurements. This work examines the measurement accuracy of an updated tool design. Methods: This current design iteration comprises improved force and inertial sensors, chosen to provide improved accuracy as well as a smaller footprint. A comprehensive series of test was carried out to quantify systematic and random measurement errors. These included noise, drift and creep measurements as well as insertion experiments where the tool data was compared to a gold standard measurement. Results: The experimental results confirm the high accuracy of the device with negligible drift and noise characteristics, moderate creep and an effective compensation of orientation-dependent gravity influences. The comparison to the gold standard shows a systematic error well below 1 mN, even with exaggerated movements during the insertion. Compared to the first published tool iteration, the uncertainties are reduced by over 80%. Conclusion: The refined version of the Forception Tool provides a higher level of accuracy, resulting in more reliable measurements. After this verification, the next step is to obtain improved intraoperative insertion force data. This will enable a more detailed analysis of the forces and thus better understanding of their impact.