Feasibility of Minimally Invasive Robot‐Assisted Retrofacial Access to the Stapedius Muscle for Applications in Objective Cochlear Implant Fitting: A Cadaveric Study

BACKGROUND: Accurate setting of maximum comfort levels (MCL) during cochlear implant (CI) fitting is essential but subjective, especially in non-cooperative patients. The stapedius reflex (SR) correlates with the MCL and offers an objective measure. Surgical access to the stapedius muscle (SM) is challenging due to its proximity to the facial nerve and sigmoid sinus; a retrofacial approach is preferred. This study evaluated the feasibility of robotic-assisted SM access via this approach. METHODS: Two cadaveric heads underwent robotic drilling using the HEARO system. Preoperative CT imaging and 3D planning with OTOPLAN defined patient-specific trajectories to the SM while maintaining safe distances from critical structures. Accuracy was assessed with postoperative CT and microscopic dissection. RESULTS: The SM was successfully achieved in both specimens with high precision and minimal invasiveness. CONCLUSIONS: Robotic-assisted retrofacial access to the SM is feasible and safe, supporting future precision surgery and closed-loop CI systems with objective SR monitoring.