Use of O-arm navigation in percutaneous pedicle screw fixation for thoracolumbar fractures in patients with ankylosing spinal disorders: reducing intraoperative radiation exposure—a retrospective cohort study

Background: Ankylosing spinal disorders (ASD), including ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis, markedly increase spinal rigidity and susceptibility to highly unstable thoracolumbar fractures. These injuries often require long-segment posterior fixation, which conventionally relies on C-arm fluoroscopy and exposes operating staff to cumulative radiation. O-arm-based intraoperative navigation may reduce radiation exposure while maintaining pedicle screw accuracy; however, evidence in ASD-related fractures remains limited. The aim of this study was to compare intraoperative radiation exposure and pedicle screw placement accuracy between O-arm navigation and C-arm fluoroscopy during percutaneous pedicle screw (PPS) fixation in patients with ASD. Methods: This single-center retrospective cohort study included 24 consecutive adults with ASD who sustained thoracolumbar fractures between 2015 and 2024. Patients underwent PPS fixation using either O-arm navigation (n=11) or C-arm fluoroscopy (n=13). Demographic characteristics, operative variables, radiation time, and screw accuracy-assessed using the Heary and Gertzbein classification systems-were compared. Fluoroscopy time served as a surrogate marker of radiation exposure because actual dosimeter data were unavailable. Results: 87.3%, respectively; P>0.99). Operative time, blood loss, and complication rates did not differ significantly between groups. Time from injury to surgery was longer in the O-arm group, reflecting workflow constraints and the use of C-arm fluoroscopy for urgent after-hours cases. Conclusions: O-arm navigation markedly reduces intraoperative radiation exposure without compromising pedicle screw accuracy in ASD-related thoracolumbar fractures. Given the substantial occupational radiation risks faced by spine surgeons, O-arm navigation represents a valuable tool for improving radiation safety while maintaining surgical precision. Larger prospective studies are warranted to validate these findings.