Sensor-based force measurement during FESS for robot assisted surgery

The main disadvantage of conventional functional endoscopic sinus surgery (FESS) for the surgeon is the restriction to one hand for manipulation while the other hand is holding the endoscope. In our project we develop an automatic anticipating robot assisted endoscope guidance during FESS. The robot guidance will be realized by a multisensor system which includes tactile control. The objective of this study was to measure forces during cadaver and patient FESS. We used a force/torque sensor mounted at the endoscope in order to measure forces which were exerted by the endoscope to nasal and paranasal tissue. The experiment was realized on 5 cadaver heads and 20 patients. Our results show that forces are lower than 7 N most of the time. It takes higher forces in frontal and maxillary sinus surgery compared to ethmoid sinus surgery. For tactile endoscope guidance it will be necessary to define local force thresholds. The results of the force measurement can be used for surgical simulations or robot assisted surgery systems.