Development and Validation of a Robot-Assisted Retraction System for Orthopedic Surgery

Tissue retraction, one of the basic steps in orthopedic surgery, is related to the smooth entry of surgical instruments into the surgical area and provides a clear surgical perspective for surgeons. This work introduces the first robot-assisted retraction system (RARS) specifically designed for orthopedic surgery. The RARS allows surgeons to set a safe retraction force and roughly set the posture of the retraction device at the beginning. To ensure that the RARS automatically completes the task in a safe manner, we propose a safety control framework that employs iterative enhanced control based on interaction model to handle the retraction interaction problem, and avoids interference with the operation of surgeons through null-space optimization. First, we performed a performance test of the RARS on a phantom model, and the results showed that the maximum tracking error of the retraction force was 0.51N, demonstrating satisfactory tracking performance. Second, we validated the effectiveness of null-space optimization by observing the evolution of joint positions. Finally, we conducted experiments on in-vivo animal and the results showed that the proposed RARS exhibited superior performance in safe retraction force tracking accuracy and tissue damage compared to traditional manual retractions.