Assessment of Vibrotactile Feedback in a Needle-Insertion Task using a Surgical Robot

The present study examined the effect of vibrotactile feedback in a needle-insertion task using a surgical robot. Four participants performed the task by hand (using a manual needle driver instrument) and by using a surgical robot, with or without vibrotactile feedback. The vibrotactile feedback signal indicated the deviation in force direction, with the signal amplitude modulated by the force magnitude. Visual feedback was always available in all experimental conditions. The participants´ task was to insert a hooked needle into a simulated tissue pad at a pre- marked entrance point and drive it out of the tissue pad at a corresponding pre-marked exit point. The participants were instructed to hold the hooked needle in an orientation that minimized side-loading on the simulated tissue pad and prevented needle rotation in the needle driver. The forces exerted by the needle on the simulated tissue pad were recorded. The results indicated that the vibrotactile display was useful in reducing the overall force-direction deviation during the needle-insertion task, but it increased task completion time. It generally took twice as long to perform the task with the robot than with the hand. One participant who was experienced with the surgical robot consistently applied less force with the robot than with the hand. The vibrotactile feedback reduced the magnitude of the force component that was perpendicular to the suturing surface, but not the forces along the suturing surface. We compare our results to those reported in the literature and discuss the challenges we faced in assessing haptic feedback in a skilled surgical task such as the one used in the present study.