A force-sensing retractor for robot-assisted transoral surgery

Purpose: In robot-assisted transoral surgery, frequent retraction operations are essential to leave space for the surgical procedure. Commercial clinical retractors are simply composed of mechanical parts and cannot sense the touching force. Methods: We propose a new retractor for robot-assisted transoral surgery. It supports sensing of the touching force when retracting the tissues. By designing the structure of the force sensors based on small piezoresistive elements, we build a sensory system that is well integrated with the retractor for transoral surgery. After calibration of the system, a simple equation is computed to decode the resultant force as well as the center of the contact location. Results: A standard measuring test is designed for the force-sensing retractor. The result shows that the measured force is up to 15 N, and the sensed force precision reaches 0.08 N with a sampling rate of 98 Hz. The dimensions of the sensory system fit the retractor well. Conclusion: The experimental results demonstrate the potential of the proposed retractor in robot-assisted surgery. The retractor supports the provision of force feedback in an interactive manipulation mode and produces haptic information for the remote side in a teleoperated surgical robot system.