An Adjustable Force Limiting And Sensing Mechanism For Laparoscopic Forceps Graspers

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Abstract

In laparoscopic surgery, surgeons may cause damage to internal tissues due excessive pinch forces while using laparoscopic forceps graspers. Low mechanical efficiency, poor haptic feedback and visual perception errors causes surgeons to be unable to correctly asses pinch forces. In this study, a new force limiting device is designed according to the BME­CI approach and tested. The new design uses a standard laparoscopic grasper as a basis and limits the pinch force with a compliant element that locks in place based on the force applied. The device underwent mechanical evaluation that looked at the force transmission of the entire force limiting mechanism, stiffness and input/output relationship of the compliant elements. The mechanical evaluation showed that the device is able to successfully limit the pinch force exerted and that a symmetrical compliant element offers better force locking and sensing characteristics compared to a non­symmetrical one. A small simulated clinical trial with 10 participants was done. The results showed that no significant difference in task time (p=0.548), slippages, meant issue handling force (p=0.462) and maximum tissue handling force (p=0.602) between the two lowered force conditions could be found. Improvements could be made regarding the sensing of forces and the exact locking characteristics