Impact of a novel spine stabilization technique on intervertebral movement in cervical spine surgery using a humanoid surgical robotic system.

Background: Navigation and robotic systems in spine surgery rely on the assumption that the spine behaves as a rigid body during surgery; however, intervertebral motion persists under typical intraoperative conditions. For robotic execution of hard-tissue procedures to be effective, the system must be capable of autonomously securing and stabilizing the target vertebra throughout the intervention. Methods: A cadaveric study was performed using 6 human cervical spine specimens. In part 1, C2-C7 vertebrae were instrumented with markers and subjected to robotically applied 30 N forces along planned pedicle screw trajectories, with and without robotic stabilization. Intervertebral motion was quantified using a 3D optical tracking system. In part 2, surgeons placed 30 cervical pedicle screws (C1-T1) using standard robot-assisted navigation and 36 screws using a novel FDA-cleared bi-manual 2-armed surgical robotic system incorporating autonomous vertebral stabilization and individual vertebra tracking. Screw accuracy was assessed by comparing planned and actual trajectories on postoperative 3D imaging. Results: Robotic stabilization reduced translational motion by up to 57.8% and rotational motion by up to 57.4% at the targeted level, with meaningful reductions at adjacent levels and diminishing effects with increasing distance. No major pedicle screw placement errors (>2 mm or >2°) were observed with stabilization. Mean angular error decreased by 31.7% (1.5 ± 1.2° vs. 1.0 ± 0.5°). Conclusions: Bi-manual robotic stabilization significantly reduced intervertebral motion and improved pedicle screw placement accuracy. Targeted intraoperative stabilization may mitigate limitations associated with spinal nonrigidity in robotic-assisted navigation.