Is haptic feedback necessary to microsurgical suturing? Comparative study of 9/0 and 10/0 knot tying operated by 24 surgeons.

Robotically assisted telemanipulators are often criticised for their lack of direct haptic feedback. However, robotically assisted microsurgical sutures have already been achieved successfully. The aim of this study was to demonstrate that haptic feedback is not necessary in microsurgery. Our series included 24 surgeons of whom 14 were micro-surgeons. Each of them had to tighten a 9/0 and a 10/0 pre-tied nylon thread until getting the sensation of optimal knot tying. The procedure was performed four times, with open and closed eyes. The quality of knot tying was evaluated (fully tied, fairly or incompletely tied, or broken thread). The results obtained with the eyes open were significantly better. Neither the material size, nor the surgeon's expertise was shown to have an impact on knot tying quality. Our results demonstrate the uselessness of haptic feedback in microsurgery.