Autonomous path planning for robot‐assisted pelvic fracture closed reduction with collision avoidance

Abstract

Background: Robot-assisted pelvic fracture closed reduction (RPFCR) positively contributes to patient treatment. However, the current path planning suffers from incomplete obstacle avoidance and long paths. Method:A collision detection method is proposed for applications in the pelvic environment to improve the safety of RPFCR surgery. Meanwhile, a defined orientation planning strategy (OPS) and linear sampling search (LSS) are coupled into the A* algorithm to optimise the reduction path. Subsequently, pelvic in vitro experimental platform is built to verify the augmented A*algorithm's feasibility. Results:The augmented A* algorithm planned the shortest path for the same fracture model, and the paths planned by the A* algorithm and experience-based increased by 56.12% and 89.02%, respectively. Conclusions:The augmented A* algorithm effectively improves surgical safety and shortens the path length, which can be adopted as an effective model for developing RPFCR path planning. K E Y W O R D SA* algorithm, collision detection, path planning, pelvic closed reduction | INTRODUCTIONUnstable pelvic fractures are the most severe injury in the body, accounting for 2%-8% of all fractures and a mortality rate of 6%-31%. 1,2 A safe and precise anatomical reduction is the cornerstone of treating pelvic fractures. 3 As a modern technology with high precision, reliability, and intelligence, robotics is widely used in medical, industrial, and aerospace fields. Therefore, the reduction movements during pelvic fracture closed reduction surgery can be performed by controlling the robot. [4][5][6] With the rapid development and application of medical robotics, 7 the path planning for robot-assisted pelvic fracture closed reduction (RPFCR) has attracted broad researchers. The RPFCR path planning can be divided into two steps: collision detection and path search.The pelvic environment is complex, with many soft and hard tissues. 8 Thus, it is necessary to detect collisions between bones or between bones and soft tissues in preoperative path planning. Meanwhile, a rational and effective path search method is required to cut the surgical intervention time.The main contribution of this paper is to propose a path-planning method for RPFCR, which improves the surgery's safety and the universality of the path planning and reduces the length of the reduction path. Firstly, the fracture model is discretised into computable point cloud data. Based on the point set of the sacrum, the space where the sacrum is located is divided into several small subspaces using the Octree data structure. Then, the point set of the dislocated ilium is traversed to conduct overlap tests with the sacral subspace to detect the collision between objects. Secondly, this paper defined an orientation planning strategy (OPS), which means changing the ilium's orientation with a small step length to avoid high reduction resistance caused by a one-time adjustment. And a linear sampling search (LSS) method is proposed to shorten the reduction path further. Finally, the

Analysis of the therapeutic efficacy of robot-assisted percutaneous screw fixation in the minimally invasive treatment of pelvic fractures

“…In our study, the robot-assisted group evinced a substantial 20% reduction in surgical time compared to the control group, alongside a remarkable 40% decrease in fluoroscopy frequency, resulting in reduced iatrogenic injury to the patients during the procedure. Moreover, the robot-assisted group in this study demonstrated superior postoperative pain management relative to the control group, which potentially be attributed to the diminished intraoperative puncture-induced damage to the pelvis and surrounding soft tissues ( 13 ). Nonetheless, it is worth considering the marginal 0.4 difference in visual analog scale (VAS) pain scores between the two groups, prompting further exploration into the significance of this subjective perception.…”

Technologies evolution in robot-assisted fracture reduction systems: a comprehensive review

“…The methods described above apply only to lower-extremity fractures. Pan et al (2023) proposed an augmented A* algorithm, 3D-OPS A*, to automatically plan reduction paths for more complex pelvic fractures. However, this approach does not guarantee a minimal resistance force during the reduction.…”

“…To ensure a smooth reduction procedure, performing any necessary pre-distraction measures, using the minimum force necessary to move the fragments, and selecting the shortest reduction path to minimize any unnecessary movement is important. However, this process is subjective, and surgeons may increase the distance between bones to avoid collisions, which creates iatrogenic injury and leads to secondary soft tissue injury (Pan et al, 2023). During operative procedures, surgeons using RAFR systems may not be able to feel the forces applied to patients in real time, unlike in other treatments.…”