Could you imagine half your face not working again? Or how about losing the ability to taste? These are very real concerns when it comes to inner ear surgery, a procedure that involves the drilling of bone behind the ear. With many nerves embedded in the bone, this dangerous procedure requires the surgeon to drill within half a millimeter of the facial nerve using only hand-eye coordination! Just one slip or miscalculation could damage the facial nerve, resulting in severe complications for the patient such as facial paralysis or loss of taste. The key to making this a safer procedure is collaboration between humans and robots. There are 120,000 of these procedures performed every year for the treatment of audiological disorders and cancer. By combining the precision and accuracy of a robot with the judgment and intuition of the surgeon, we can help surgeons restore hearing to deaf patients, and save the lives of cancer patients, in a much safer and more accurate manner.
This research focusses on developing an inherently safe robotic system that will help guide the hand of the surgeon during drilling to ensure no damage to the facial nerve or other bone embedded vital anatomy. In this system, both the surgeon and the robotic system simultaneously hold the surgical drill and work as a team to ensure safe and effective drilling of the patient’s skull. Before the drilling starts, the surgeon uses preoperative 3D images of a patient’s head, to define exactly what bone needs to be removed and point out where the nerves, blood vessels, and ear canal are so that these vital anatomical structures can be avoided. This establishes an “off limits” region constraint. As the robotic system and surgeon collaboratively hold the drill, impedance of the device are minimized to give the surgeon full maneuverability when far away from vital anatomy. When the surgeon approaches the vital anatomy, the robot provides force feedback to alert the surgeon to the presence of the “off limits” constraint.