Development of Remote Center of Motion Mechanism for Biportal Endoscopic Spine Surgery Robot
Chunwoo Kim, Chaewon Kim, Dong-Eun Choi
AI summary
Problem
Existing surgical robots for minimally invasive spine surgery lack sufficient stiffness to manipulate hard tissues and are often too bulky to avoid interference with intraoperative X-ray fluoroscopes.
Approach
The authors modified a belt-driven RCM mechanism by adding gearboxes to reduce belt tension and elastic deformation, and relocated the instrument insertion prismatic joint to the base to shrink the end effector size.
Key results
- RCM point accuracy of 0.56 mm
- Repeatability of 0.019 mm
- Stiffness of 11.676, 12.435, and 5.341 N/mm in X, Y, and Z directions
- Feasibility validated via simulated BESS on a spine phantom
Why it matters
Provides a critical mechanical foundation for developing compact, stiff teleoperated robots tailored for demanding endoscopic spine procedures.
Abstract
Remote Center of Motion (RCM) mechanism is widely used in surgical robots for Minimally Invasive Surgery (MIS). For endoscopic spine surgery, the surgical robot requires RCM mechanism with sufficient stiffness and compact end effector to manipulate hard tissues while avoiding interference with other instruments. This paper presents a modified belt- driven RCM mechanism designed to meet these specific re- quirements of the endoscopic spine surgery. Gearboxes were incorporated to the belt-driven Remote Center of Motion (RCM) mechanism to reduce belt tension and resulting elastic deformation, while the RCM constraint is maintained through a specific relationship between gearbox reduction ratios. The prismatic joint for instrument insertion is relocated to the base to reduce the size of the end effector. Prototype of a surgical robot with the presented RCM mechanism achieved an RCM point accuracy of 0.56 mm, repeatability of 0.019 mm, and stiffness of 11.676, 12.435, and 5.341 N/mm in the X, Y, and Z directions, respectively. Feasibility of the robot was validated through simulated BESS on a spine phantom.