Automatic path planning for pelvic fracture reduction with multi-degree-of-freedom

Background and objectives: Computer-assisted orthopedic surgical techniques and robotics has improved the therapeutic outcome of pelvic fracture reduction surgery. The preoperative reduction path is one of the prerequisites for robotic movement and an essential reference for manual operation. As the largest irregular bone with complicated morphology, the rotational motion of pelvic fracture fragments impacts the reduction process directly. To address this, the primary objective of this study is to develop an efficient and effective algorithm for automatically planning the reduction trajectory in robot-assisted pelvic fracture surgeries. Methods: After obtaining rotational and reorientated translational degrees of freedom through the initial and target positions of the fracture fragments, the initial path is acquired through improved path planning method combined with specific designed collision detection algorithm. The final reduction path is post-processed to be shortened and smoothed. The effectiveness of the algorithm was evaluated in various pelvic fracture models with surrounding muscles and was compared with prior relevant implementations. Results: Simulation results showed the ability of the planner to save time and overcome the state of art in terms of collision detection, path length and smoothness, search time, and surrounding muscle stretching conditions. Conclusions: The proposed method enables a reasonable reduction path for pelvic fracture, which is demonstrated to be superior in various pelvic fracture scenarios.