Force control for tissue tensioning in precise robotic laser surgery

Lasers are being used in various surgical procedures to remove tissue or bones, to coagulate vessels or other structures. Due to difficulties in handling only a limited number of surgeons manage to display sufficient levels of precision in Minimally Invasive Surgery (MIS) procedures. Prior works on robotic laser surgery demonstrated shorter learning curves and higher ablation precision, but unfortunately ignored the fact that most clinically relevant tasks are bi-manual by nature. Surgeons are also reluctant to use current commercial surgical robotic systems for complex laser tasks, indicating that the lack of haptic feedback prevents them from efficient and safe tissue handling in preparation of laser treatment. This paper expands earlier robotic laser work towards bi-manual operation. The paper introduces a system for precisely tensioning tissue that is being targeted by the laser. An artificial test-setup that captures some essential features of bimanual laser surgery is described. Experiments have been conducted to investigate the effect of haptic feedback on ablation performance. A comparison is made of achievable levels of ablation precision when there is no haptic feedback, when there is haptic feedback and when an automatic tension control algorithm is deployed. The conducted experimental results confirm the great potential of haptic feedback and automatic tensioning systems for complex bi-manual lasering tasks.