Robot-Assisted Versus Fluoroscopy-Assisted Cortical Bone Trajectory Screw Instrumentation in Lumbar Spinal Surgery: A Matched-Cohort Comparison

OBJECTIVE: The aim of the present study was to compare the accuracy and safety of TiRobot system-assisted with those of fluoroscopy-assisted cortical bone trajectory screw placement in lumbar spinal surgery. METHODS: We included 58 patients who required instrumentation in a retrospective matched-cohort study. The primary outcome measures were the accuracy of screw placement using the modified Gertzbein-Robbins scale and the incidence of proximal facet joint violation. Secondary outcome measures included operative time, intraoperative blood loss, postoperative hospital stay, radiation exposure, and complications. RESULTS: A total of 231 screws were placed (TiRobot group [RG], 86 screws; fluoroscopy group [FG], 145 screws). In the RG, 87.2% of the screws had perfect positions (grade A). The remaining screws were grade B (8.1%) and C (4.7%). In the FG, 66.9% of the screws had perfect positions (grade A). The remaining screws were grade B (20.0%), C (9.0%), and D (4.1%). The proportion of clinically acceptable screws (grade A or B) was greater in the RG than in the FG. In the RG, the most common direction of screw deviation was cephalad endplate and was the vertebral cortex in FG. No difference was found in facet joint violation between the 2 groups. The operative time and blood loss were slightly greater in the RG than in the FG. No statistically significant difference was found in the postoperative hospital stay between the 2 groups. The mean cumulative radiation time was greater for the RG than for the FG, but the radiation exposure to the surgeon was significantly lower in the RG than in the FG. CONCLUSIONS: Robot-assisted screw placement is more accurate and safe compared with fluoroscopy-assisted placement for lumbar spinal cortical bone trajectory instrumentation.