Evaluation of Surgical Performance after Extended Laparoscopic Training using Physical Haptic Constraints

Laparoscopic training often lacks an emphasis on proper grip of the instrument. Novices will often over-grip handle, restricting the thumb's range of motion and preventing them from pivoting the tool within their grasp. Limiting the thumb's range of movement can impact the force applied by the surgical instrument tips. We developed a passive and active constraint to prevent over-gripping. Initial experiments showed significant improvements in grip as well as task performance when evaluated using standard surgical training tasks. In this paper, we evaluate the effects of extended practice with these haptic constraints on skill acquisition. For this study, 12 novices were recruited to complete four trials consisting of three tasks each. Subjects were randomly assigned into a control group, a passive constraint group, and an active constraint group. The middle two trials were performed using the constraints but the first and last trials were conducted without constraints to measure lasting effects of using the constraints. The 3D movement of the instrument tips were measured with electromagnetic trackers and a custom sensing glove was used to measure finger tip position along the instrument handle. Metrics of path length, motion smoothness, depth perception, volume of motion, and velocity were computed from the instrument motion data. A score for each trial was also calculated and was derived from the task completion time. After a period of extended practice, the active constraint group had significantly less over-grip compared to the control group. This group additionally showed significantly lower volumes of motion. The passive constraint also showed consistently lower integrated jerk measurements through the trials indicating long-term benefits of the constraints.