Robotic system with programmable motion constraint for transurethral resection

Purpose We propose a tele-operated transurethral robotic system with programmable motion constraint for tissue resection. Methods The system consists of a surgeon console with an interaction device, a 7-degree-of-freedom manipulator, and a surgical end-effector. The surgical end-effector holds a resectoscope with a motor driven mechanism to perform electrocautery. Instrumental motion with remote center-of-motion (RCM) constraint is important for transurethral procedures since the damage to the healthy structures can be minimized. A screw theory-based programmable RCM generator is proposed to map the inputs of the interaction device to the RCM manifold in the manipulator space. To achieve smooth real-time manipulator following control with RCM constraint, an online trajectory planner is presented. Results Experiments were performed to evaluate the motion precision and accuracy. The results show that both the RCM precision and accuracy were less than 1 mm. Ex-vivo experiments of robotic resection of soft tissue were also carried out. The results show that our robotic system could achieve instrumental manipulation and delicate cutting under the real-time control of a surgeon. Conclusions Our robotic system could assist surgeons in performing transurethral procedures in a remote manner with potential advantages of being accurate, less laborious and clean.