Verrotouch: Detection of Instrument Vibrations for Haptic Feedback and Skill Assessment in Robotic Surgery

Objective: Surgeons currently rely on visual cues to compensate for the lack of haptic information during robotic minimally invasive surgery (RMIS). We have developed VerroTouch, an RMIS accessory that provides surgeons with realistic audio and haptic feedback of instrument vibrations. This system has been implemented in both a box-trainer and a live porcine model. The objectives of current studies are to assess instrument vibrations as a measure of surgeon skill and to determine the effects of haptic feedback on robotic surgery training.

Description: Accelerometers that measure tool vibrations are mounted to the patient-side manipulators of a da Vinci S robotic surgical system. These sensors lie within the sterile drapes, avoiding the need for sterilization. The measured right and left tool vibrations are processed and relayed to speakers on the surgeon’s console and to voice coil actuators attached to the console handles. Previously, eleven surgeons used a VerroTouch-augmented da Vinci S to perform three in-vitro manipulation tasks under four feedback conditions: with visual feedback, visual-audio feedback, visual-haptic feedback, and visual-audio-haptic feedback. Additionally, two transperitoneal nephrectomies and two-midureteral dissections with uretero-ureterostomy were performed by two urologists on a porcine model using a da Vinci S augmented with VerroTouch for in-vivo validation.

Results: Surgeons who participated in the manipulation task study significantly preferred some form of tool vibration feedback over visual feedback alone. Survey ratings and written comments also indicate that the additional feedback significantly improved subjects’ concentration. No significant differences in root mean square (RMS) force, RMS acceleration, or task completion time were found across feedback conditions. In the porcine model, human review of a 30-minute operation excerpt resulted in identification of 1404 manipulation events; subsequent analysis demonstrated that 82% of identified events resulted in significant vibrations that were measured by VerroTouch.

Conclusion/Future Directions: VerroTouch has been successfully implemented both in vitro and in vivo and proved reliable in detecting technically relevant instrument manipulation events. VerroTouch is currently being modified for compatibility with the da Vinci Standard and Si models. While surgeons tend to prefer the presence of its feedback, further quantitative studies of the cognitive ergonomic effects of VerroTouch are required. We hypothesize that the presence of tool vibration feedback may lead to improved control of the surgical instruments, particularly for novices. Studies to test the utility of VerroTouch as an assessment tool for surgical skill and a prospective study of the effects of vibrotactile feedback on training novice surgeons are planned.

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