Utility of Confirmatory Navigational CT Spins in Patients Undergoing One- to Two-Level Instrumented Posterior Fusions

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To evaluate the clinical utility of confirmatory Navigational CT (NavCT) spins after pedicle screw placement in one- to two-level posterior lumbar fusions. SUMMARY OF BACKGROUND DATA: Navigational CT improves pedicle screw accuracy and reduces blood loss; however, some surgeons perform an additional confirmatory CT spin after screw placement to verify trajectory prior to closure. Confirmatory imaging increases operative time, cost, and radiation exposure, and its benefit in routine lumbar fusion remains unclear. METHODS: Adult patients undergoing one- to two-level posterior instrumented lumbar fusion between January 2020 and June 2021 were identified and stratified into three cohorts: no navigation (NoNav), navigation only (NavCT), and navigation with confirmatory spin (NavCT+C). Primary outcomes included intraoperative screw repositioning and return to the operating room for screw revision. Secondary outcomes included operative duration, estimated blood loss (EBL), discharge disposition, perioperative complications, and one-year follow-up events. RESULTS: A total of 339 patients were included (117 NoNav, 162 NavCT, 60 NavCT+C). Screw-related complications were rare; intraoperative repositioning (1 vs. 2 vs. 0, P=0.683) and reoperation for screw revision (1 vs. 1 vs. 0, P=0.780) did not differ across groups. The absolute risk reduction for reoperation with confirmatory imaging was 0.72%, yielding an NNT of 138.5. Operative time differed significantly (199.3 vs. 176.5 vs. 205.4 min, P=0.01). EBL was significantly lower in both NavCT groups compared with NoNav (P <0.001). Perioperative complications and length of stay were similar. Confirmatory imaging increased radiation exposure and operative duration without improving screw-related outcomes. CONCLUSION: In one- to two-level lumbar fusions, confirmatory NavCT spins provide minimal additional clinical value. Given increased radiation, time, and cost with no observed improvement in screw accuracy or reoperation rates, confirmatory imaging should be used selectively rather than routinely.