Steerable Robot-assisted Micromanipulation in the Middle Ear: Preliminary Feasibility Evaluation.

HYPOTHESIS The use of a robotic manipulator with a dexterously orientable gripper will expand the ability of middle ear surgeons to perform precise tasks and access otherwise challenging anatomic regions. BACKGROUND Middle ear surgery presents unique challenges because of the constrained operative space and limited access to certain anatomic regions. METHODS A custom-designed robot with a sideways-reaching gripper was used to evaluate feasibility of manipulation tasks in different middle-ear anatomical zones. Reachable workspace within the middle ear, accuracy of free-space path following, and tool steadiness were compared between robotic telemanipulation and manual control. Preliminarily assessments of the robot's clinical utility included: 1) touching the round window niche, Eustachian tube orifice, and sinus tympani; 2) placing a stapes prosthesis; 3) removal of mockup diseased tissue in the sinus tympani. RESULTS The reachable workspace in the middle ear was considerably greater with the robot as compared with manual manipulation using a Rosen needle. In a simple path-tracing task outside the ear, robotic telemanipulation was associated with significantly reduced error. Within the middle ear, the robot contributed to steadier movement, but longer task completion time. The gripper successfully placed a 4.5 mm piston prosthesis, accessed the round window niche, Eustachian tube orifice, and removed mockup disease from the sinus tympani. CONCLUSION This study demonstrates that robotic assistance using steerable tools allows surgeons to access challenging anatomic regions of the middle ear. Coordinated and accurate manipulation is evidenced by motion analyses and completion of feasibility tasks within the middle ear.