Design and analysis of an actuated endoscopic grasper for manipulation of large body organs

During laparoscopic surgery, grasping of large body organs such as spleen, kidney, and liver, is a difficult task using conventional instruments. This paper describes the design and analysis of a novel actuated endoscopic grasper for manipulation of large internal organs. The designed instrument resembles a miniaturized three fingered hand with each finger consisting of two links. It could pass through a 10 mm trocar and then be opened inside the abdomen to grasp body organs up to 80 mm diameter. A detailed force analysis of the mechanism revealed that high actuating forces are required to grasp large organs. In order to facilitate the actuation of the grasper, its dimensions were optimized against the needed actuating force and an electro-mechanical actuator was designed to activate the system. Design optimization of the grasper resulted in up to 40% decrease in the required actuating force which could be effectively produced by a small linear actuator, with a moving course of 10 mm, placed inside the instrument handle. Finally, the efficacy of the actuated endoscopic grasper during a laparoscopic surgery operation was demonstrated using computer simulation.