Robotic-assisted spine surgery allows for increased pedicle screw sizes while still improving safety as indicated by elevated triggered electromyographic thresholds

Abstract

The present study used triggered electromyographic (EMG) testing as a tool to determine the safety of pedicle screw placement. In this Institutional Review Board exempt review, data from 151 consecutive patients (100 robotic; 51 non-robotic) who had undergone instrumented spinal fusion surgery of the thoracic, lumbar, or sacral regions were analyzed. The sizes of implanted pedicle screws and EMG threshold data were compared between screws that were placed immediately before and after adoption of the robotic technique. The robotic group had significantly larger screws inserted that were wider (7 ± 0.7 vs 6.5 ± 0.3 mm; p < 0.001) and longer (47.8 ± 6.4 vs 45.7 ± 4.3 mm; p < 0.001). The robotic group also had significantly higher stimulation thresholds (34.0 ± 11.9 vs 30.2 ± 9.8 mA; p = 0.002) of the inserted screws. The robotic group stayed in the hospital postoperatively for fewer days (2.3 ± 1.2 vs 2.9 ± 2 days; p = 0.04), but had longer surgery times (174 ± 37.8 vs 146 ± 41.5 min; p < 0.001). This study demonstrated that the use of navigated, robot-assisted surgery allowed for placement of larger pedicle screws without compromising safety, as determined by pedicle screw stimulation thresholds. Future studies should investigate whether these effects become even stronger in a later cohort after surgeons have more experience with the robotic technique. It should also be evaluated whether the larger screw sizes allowed by the robotic technology actually translate into improved long-term clinical outcomes.