Objective differentiation of force-based laparoscopic skills using a novel haptic simulator

Background: There is a growing need for effective surgical simulators to train the novice resident with a core skill set that can be later used in advanced operating room training. The most common simulator-based laparoscopic skills curriculum, the Fundamentals of Laparoscopic Skills (FLS), has been demonstrated to effectively teach basic surgical skills; however, a key deficiency in current surgical simulators is lack of validated training for force-based or haptic skills. In this study, a novel haptic simulator was examined for construct validity by determining its ability to differentiate between the force skills of surgeons and novices. Methods: A total of 34 participants enrolled in the study and were divided into two groups: novices, with no previous surgical experience and surgeons, with some level of surgical experience (including upper level residents and attendings). All participants performed a force-based task using grasping, probing, or sweeping motions with laparoscopic tools on the simulator. In the first session, participants were given 3 trials to learn specific forces associated with locations on a graphic; after this, they were asked to reproduce forces at each of the locations in random order. A force-based metric (score) was used to record performance. Results: On probing and grasping tasks, novices applied significantly greater overall forces than surgeons. When analyzed by force levels, novices applied greater forces on the probing task at lower and mid-range forces, for grasping at low-range forces ranges and, for sweeping at high-range forces. Conclusions: The haptic simulator successfully differentiated between novice and surgeon force skill level at specific ranges for all 3 salient haptic tasks, establishing initial construct validity of the haptic simulator. Based on these results, force-based simulator metrics may be used to objectively measure haptic skill level and potentially train residents. Haptic simulator development should focus on the 3 salient haptic skills (grasping, probing, and sweeping) where precise force application is necessary for successful task outcomes.