Effects of experience on force perception threshold in minimally invasive surgery

Background Distorted haptic feedback by the surgical instrumentation is a major problem in minimally invasive surgery (MIS). Friction force generated by the rubber seal in the trocars masks the haptic information needed to perceive the properties and structure of the target tissue, resulting in an increased haptic perception threshold in naïve subjects. This can lead to over application of forces in surgery. Objective This paper examines the effect of surgical experience on the psychophysics of force perception and force application efficiency in MIS. Method A controlled experiment was conducted using a mixed design, with friction and vision as independent within-subjects factors, experience as a between-subjects factor, and applied force and detection time as dependent measures. Fourteen subjects (eight novices and six experienced surgeons) performed a simulated tissue probing task. Performance data were recorded by a custom-built force-sensing system. Results When friction was present, higher thresholds and longer detection times were observed for both experienced and inexperienced subjects. In all cases, experienced surgeons applied a greater force than novices, but were quicker to detect contact with tissue, resulting in higher force application efficiency. Conclusion Surgeons seem to have adapted to the higher threshold in haptic perception by reacting faster, even while applying more force to the tissue, keeping within the limits of safety.