A Hand-Guided Robotic Drill for Vestibular Implant Surgery—Feasibility of Preventing Membranous Labyrinth Rupture

ImportanceProgress in vestibular implantation offers hope for patients with bilateral vestibulopathy. However, surgically opening the semicircular canals risks breaching the membranous labyrinth, which may induce sensorineural hearing loss. A robotic drill sensing force and torque might prevent membranous labyrinth rupture.Primary objectiveTo assess the feasibility of force- and torque-based automatic cessation in a hand-guided robotic drill for fenestrating the bony semicircular canals without rupturing the membranous labyrinth.Secondary objectiveTo fit an electrode dummy through the fenestrations.DesignFeasibility study using human cadaveric temporal bones.SettingLaboratory.ParticipantsTen formalin-fixed human temporal bones.InterventionAfter performing a cortical mastoidectomy and skeletonizing the semicircular canals, a hand-guided robotic drill was used to drill 2 fenestrations in each semicircular canal. A silicone electrode dummy was inserted through each fenestration.Main outcome measuresProportion of fenestrations with intact membranous labyrinth, as evaluated with a surgical microscope. Proportion of fenestrations allowing electrode insertion without additional manipulation.ResultsA total of 60 fenestrations were made in 30 semicircular canals from 10 temporal bones. Technical issues related to drill bit fixation occurred in 6 fenestrations. The remaining 54 fenestrations were all made without visible damage to the membranous labyrinth. In 81% of these fenestrations (44/54), the electrode could be advanced without requiring additional manipulation. The technical issue was related to improper alignment of the drill bit, leading to incorrect force and torque sensing.ConclusionsForce- and torque-based automatic cessation in a hand-guided robotic drill is feasible for fenestrating the bony semicircular canals without rupturing the membranous labyrinth. However, improved burr fixation is required for consistent and reliable performance.RelevanceThe investigated approach holds potential to improve safety and precision in semicircular canal surgery, such as vestibular implantation. This may expand treatment options for patients with residual inner ear function.