The Accuracy of Navigated Vs. Robot-Assisted Pedicle Screw Placement in Spine Surgery: a Retrospective Single-Centre Comparative Study

Retrospective comparative cohort study. Accurate pedicle screw placement is critical for spinal stability and for preventing neurological or vascular injury. This study compared screw-placement accuracy and safety between robot-assisted and navigation-guided pedicle screw implantation and explored differences between intraoperative 3D-fluoroscopy and preoperative CT-based surface-matching registration. We assessed all consecutive patients who underwent robot-assisted or navigation-guided pedicle screw placement at our department between 2018 and 2022. For robot-assisted placement, screw trajectories were planned on preoperative CT, and intraoperative patient registration was performed using two radiographs fused with a preoperative CT. Navigation-guided placement used either intraoperative 3D-fluoroscopy registration in the final prone position or CT-based surface matching using preoperative supine CT images. Screw positions were evaluated on postoperative CT using a standardised ordinal grading scale from 0 to 4, with Grades 3–4 defined as clinically relevant malpositions. We analysed accuracy using generalised estimating equations with patient-level clustering and adjustment for covariates. We also assessed operative time, radiation exposure, complications, and revision rates. We analysed 1,718 pedicle screws from 268 patients: 728 were robot-assisted and 990 navigation-guided, including 579 using 3D-fluoroscopy and 411 using CT-based surface matching. Mean screw grades were 0.956 for robot-assisted placement, 0.864 for navigation overall, 0.807 for 3D-fluoroscopy, and 0.944 for surface matching. After accounting for patient clustering and adjustment, screw grade did not differ significantly between navigation-guided and robot-assisted placement (aOR 0.87, 95