Evaluation of a new robotic spinal surgical system for K-wire placement characterized by tracker registration and lateral force sensing

Efficient registration and high-precision K-wire guidance are critical for the effective performance of spinal surgical robots. We therefore evaluate a new robotic system featuring optical tracker registration and a high-precision lateral force sensing system during K-wire placement. In this study, retrospectively collected clinical data were used to evaluate the technical efficacy and clinical utility of the system in spinal surgery. This was a retrospective study. Between December 2022 and April 2024, a total of 127 patients were enrolled and subjected to X-ray, CT, and MRI examinations. Among these patients, 67 were enrolled in the robot-assisted group, in which K-wires were implanted using a new spinal surgical robot. The remaining 60 patients were enrolled in the freehand group, where K-wires were implanted manually. The data collected included sex, age, body mass index, number of punctures (NOP), mean time required to insert a K-wire (MTRI K-wire), average blood loss per K-wire insertion (ABL K-wire), fluoroscopy count per K-wire (FC K-wire), puncture abduction angle (PAA), and K-wire in the pedicle (K-wire IP). Distance deviations and angle deviations were used as the primary parameters to evaluate the accuracy of the new spinal surgical robot. Compared with free-hand K-wire insertion, robot-assisted K-wire implantation results in fewer NOP, fewer MTRI K-wires, fewer ABL K-wires, fewer intraoperative FC K-wires, and a larger PAA. Compared with the free-hand group, the robot-assisted group demonstrated significantly smaller entry point deviation (0.98 ± 0.13 vs. 5.08 ± 1.17 mm, p < 0.001) and endpoint deviation (1.38 ± 0.20 vs. 5.52 ± 0.87 mm, p < 0.001). These results demonstrate superior targeting accuracy with robotic assistance relative to conventional freehand techniques. Our spinal surgical robot system demonstrates clinically reliable accuracy in K-wire placement while offering significant intraoperative advantages, including a streamlined procedural workflow, a reduced operation time, and minimal tissue trauma. These results demonstrate significant potential for both clinical implementation and further technological optimization. This trial was approved by the Ethics Committee of the Second Affiliated Hospital of Nanjing Medical University on February 21, 2023(2023XJ00401 retrospectively registered).