Dexterity enhancement in endoscopic surgery by a computer-controlled mechanical wrist

The use of conventional endoscopic instruments results in inaccurate and time-consuming techniques due to the limited range of motion. Telemanipulation systems may overcome these constraints. This study compares individual performance using a surgical tele-manipulator with either four or six degrees of freedom (DOF). Twenty non-professionals and 10 professionals (endoscopic surgeons; > 100 endoscopic procedures) performed a specially-designed set of tasks using the Intuitive Surgical telemanipulation system at full capacity with six DOF, or in a reduced mobility mode with only four DOF (wrist-locked). Time and error rate for performing each task were assessed. In the non-professional group both time to perform the tasks and error rates were reduced when working with a six DOF system, as compared with the four DOF system. Dexterity enhanced by using the wrist reduced the time needed to complete a complex endoscopic task by 40%. In the professional group the time needed to perform the task was significantly less using the six DOF system for all four tasks; the error rate was also significantly lower (except for Task III). These results confirm that a six DOF telemanipulation system enhances dexterity as compared with a four DOF system. A six DOF system provides higher speed and accuracy for performing endoscopic microsurgery and should preferably be used in complex surgical procedures.