Unitree G1 Robot Performs First Live Gallbladder Surgery
Researchers at the University of California, San Diego (UCSD) have demonstrated the first live surgery performed by a general-purpose humanoid robot, successfully completing laparoscopic cholecystectomies on pigs. The findings, published on July 8 in Nature, mark a significant advancement in surgical robotics by showcasing a platform designed for accessibility and versatility rather than the specialized infrastructure typical of current market leaders. The robotic system, termed Surgie, is built upon a Unitree G1 humanoid robot weighing 27 kilograms and standing 1.5 meters tall. In stark contrast to the da Vinci surgical system, which weighs over 800 kilograms and costs between 1.8 and 2.5 million dollars, Surgie operates with a fraction of the mass and projected expense. The platform adapts commercial wrist-mounted laparoscopic instruments via a custom connection interface, allowing the robot to mimic human surgeon movements. Teleoperation is managed by a human operator using a master telemanipulator and a stereoscopic VR headset. The research team executed two procedures: one involving a single robot assisted by a human surgeon, and a second featuring collaborative operation by two humanoid robots positioned side-by-side. Both surgeries were completed without conversion to traditional methods, though the live operations required management of mild bile leakage and bleeding. A key technical achievement is the implementation of a virtual remote center of motion (RCM). Specialized surgical robots utilize fixed mechanical pivots to ensure instruments rotate around trocar entry points, a constraint humanoid robots lack. The UCSD team developed a virtual RCM system using ArUco visual markers and real-time inverse kinematics to maintain correct instrument angles dynamically. Bench tests indicated that Surgie's precision matches that of the da Vinci Research Kit, with a weighted error of 4.53 compared to 4.59 in manual tasks. However, the humanoid system exhibited lower speed and an operational latency of approximately 156 milliseconds. During live surgeries, virtual RCM drift caused by respiration and base movement necessitated periodic pauses exceeding three minutes for recalibration. The development addresses a pressing global healthcare challenge, where 67 percent of the population lacks access to basic surgical services. The da Vinci system's size, cost, and room requirements render it impractical for low-resource settings, remote communities, field hospitals, or space missions. Surgie's portability and low weight overcome these barriers, while its nature as a general-purpose robot allows for dual utility in ancillary tasks such as instrument transport and room sanitation. Despite the milestone, clinical translation faces substantial hurdles. Researchers identified limitations in the robot's range of motion, force output, and the lack of a validated sterile protocol. The system currently possesses zero autonomy, relying entirely on human teleoperation. While the demonstration proves technical feasibility, the gap between laboratory success and clinical reliability mirrors challenges encountered by early robotic surgery decades ago. Future work must prioritize speed, calibration stability, and autonomous capabilities to bridge the divide between feasibility and widespread clinical utility.
