Quantifying Soft-Surgery in Cochlear Implantation: Multimodal Data From 30 International Specialists

To quantify how surgical behavior influences intracochlear mechanical stress during cochlear implantation using objective multi-sensor data from a large cohort of specialist cochlear implant (CI) surgeons.

Thirty internationally recognized surgeons each performed bilateral insertions in mechanically representative artificial temporal bone models. Insertion force, pressure, and electrode kinematics were captured, and six trauma-related metrics were combined into a composite soft-surgery score. Associations with surgical experience, self-assessment, and handling behaviors were analysed using nonparametric statistics.

Marked variability was observed across all metrics. Surgeons with < 50 lifetime insertions performed significantly worse than experienced colleagues. Self-assessment showed no correlation with objective outcomes. Excessively slow insertions and frequent electrode regrasping were associated with higher pressure exposure, greater force variation, and increased intracochlear implant motion. Post-insertion handling contributed substantially to intracochlear stress.

Surgical behavior decisively influences intracochlear mechanical stress in CI. Steady, uninterrupted advancement at slow to moderate speed, avoidance of array regrasping, and careful post-insertion handling reduce mechanical load. Because self-assessment proved unreliable even among specialist CI surgeons, structured training with quantitative feedback and intraoperative monitoring is essential to refine soft-surgery technique, preserve residual hearing, and optimize hearing outcomes.

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