O-Arm Accuracy and Radiation Exposure in Adult Deformity Surgery

In long thoracolumbar deformity surgery, accurate screw positioning is critical for spinal stability. We assessed pedicle and pelvic screw accuracy and radiation exposure in patients undergoing long thoracolumbar deformity fusion surgery (≥4 levels) involving 3-dimensional fluoroscopy (O-Arm/Stealth) navigation.

In this retrospective single-center cohort study, all patients aged >18 years who underwent fusion in 2016-2018 were reviewed. O-Arm images were assessed for screw accuracy. Effective radiation doses were calculated. The primary outcome was pedicle screw accuracy (Heary grade). Secondary outcomes were pelvic fixation screw accuracy, radiation exposure, and screw-related perioperative and postoperative complications or revision surgery within 3 years.

Of 1477 pedicle screws placed in 91 patients (mean 16.41 ± 5.6 screws/patient), 1208 pedicle screws (81.8%) could be evaluated by 3-dimensional imaging after placement. Heary Grade I placement was achieved in 1150 screws (95.2%), Grade II in 47 (3.9%), Grade III in 10 (0.82%), Grade IV in 1 (0.08%), and Grade V in 0; Grade III-V were replaced intraoperatively. One of 60 (1.6%) sacroiliac screws placed showed medial cortical breach and was replaced. The average O-Arm-related effective dose was 29.54 ± 14.29 mSv and effective dose/spin was 8.25 ± 2.65 mSv. No postoperative neurological worsening, vascular injuries, or revision surgeries for screw misplacement were recorded.

With effective radiation doses similar to those in interventional neuroendovascular procedures, the use of O-Arm in multilevel complex deformity surgery resulted in high screw accuracy, no need for surgical revision because of screw malposition, less additional imaging, and no radiation exposure for the surgical team.