Forces and displacements in colon surgery

Background: This study aims to find criteria for designing safer laparoscopic graspers for manipulation of delicate tissues. Since the experiment was performed in an open-surgery setup without any movement restrictions, the results are relevant to general surgery as well as laparoscopic. Method: Four surgeons were asked to apply via two clamps enough force to a pig's colon to stretch the mesocolon for dissection. Directions, magnitudes, and application points of the forces were recorded. Results: The surgeons applied per clamp on average 2.5 N and maximally 5 N to the colon. These forces were at an angle of about 40degrees to 70degrees relative to the horizontal plane and approximately 60degrees relative to each other. Conclusions: Safe laparoscopic graspers should be able to transmit at least a 5 N pull force to the tissue without damaging it. To minimize the forces used, the angles mentioned should be taken into account when placing the trocars.