Learning from visual force feedback in box trainers: tissue manipulation in laparoscopic surgery

Currently, task time and errors are often used as performance parameters in laparoscopic training. Training with the focus on task time improvement alone results in fast, but possibly less controlled, instrument movements and therefore suboptimal tissue handling skills. Twenty-five medical students were randomly assigned in two groups. Both groups performed a tissue manipulation task six times. During this training session, the time feedback group (n = 13) received real-time visual feedback of the task time. The force feedback group (n = 12) received real-time visual feedback of the tissue manipulation force. After the training sessions, participants in both groups performed an entirely different task without visual feedback. Task time, force, and motion parameters of this posttest were used to compare the technical skills of the medical students. The training data of the group that received force feedback showed a learning curve for the mean and max absolute force, max force area, force volume, task time, and path length of both instruments. The data from the group that received time feedback showed a learning curve for the max force, task time, and path length of both instruments. In the posttest, the parameters of mean absolute force (p = 0.039), max force (p = 0.041), and force volume (p = 0.009) showed a significant difference in favor of the group that received force feedback. The learning curves and the posttest indicate that training with visual force feedback improves tissue handling skills with no negative effect on the task time and instrument motions. Conventional laparoscopic training with visual time feedback improves instrument motion and task time, but it does not improve tissue manipulation skills.