Assisting Control of Forces in Laparoscopy Using Tactile and Visual Sensory Substitution

Abstract

It is widely recognized that despite its many benefits, the ergonomics of laparoscopic surgery lead to severe perceptual distortions for the surgeon. In particular, interaction forces at the instrument tip are masked by interfering forces at the trocar and distorted due to a lever effect around the insertion point. This leads to improper control of tool-tip interaction forces, increasing the risk and occurrence of intra-operative injuries, unnecessary trauma to healthy tissue and suture breakage. Here, we propose an experiment aimed at determining the efficacy and usability of cutaneous vibrotactile and/or visual feedback of tool-tip interaction forces in assisting a surgeon in controlling fine interaction forces. 16 novice subjects performed force-reach and -hold tasks in a laparoscopic setting under provision of 9 forms of feedback (visual, 4 variants of vibrotactile feedback, and their combinations). Feedback increased precision (up to 85.8 % reduction in error when aiming for a target force), repeatability (up to 84 % reduction in spread of aiming errors), speed of reaching a target force (up to 18-fold increase in speed of reaching a target force at equal accuracy) and reduced force drift over time (${{>}}68$ % reduction in cumulative deviation from a target force over a 20 s period). Results show best performance for visual feedback, with promising performance for pulsed vibrotactile feedback, allowing us to draw initial conclusions on the potential for using tactile feedback to represent interaction forces in laparoscopy and to gain insights into axes for its improvement.