Force feedback and basic laparoscopic skills.

Background: Not much is known about the exact role of force feedback in laparoscopy. This study aimed to determine whether force feedback influences movements of instruments during training in laparoscopic tasks and whether force feedback is required for training in basic laparoscopic force application tasks.

Methods: A group of 19 gynecologic residents, randomly divided into two groups, performed three laparoscopic tasks in both the box trainer and the virtual reality (VR) trainer. The box-VR group began with the box trainer, whereas the VR-box group began with the VR trainer. The three selected tasks included different levels of force application. The box trainer provides natural force feedback, whereas the VR trainer does not provide force feedback. The performance of the two groups was compared with regard to time, path length, and depth perception.

Results: For the tasks in which force plays hardly a role, no differences between box-VR group and the VR-box group were found. During a task in which force application (pulling and pushing forces) plays a role, the box-VR group outperformed VR-box group in the box trainer. Moreover, training with the box trainer had a positive effect on subsequent performance of the task with the VR trainer. This was not found the other way around. No differences were found between box-VR and the VR-box group in tasks not requiring force application.

Conclusion: Force feedback influences basic laparoscopic skills during tasks in which pulling and pushing forces are applied. For these tasks, the switch from the trainer without force feedback to the one with natural force feedback has a detrimental effect on performance. Therefore, training for tasks in which forces play an important role (e.g., stretching, grasping) should be done using systems with natural force feedback, whereas eye-hand coordination can be trained without force feedback.