Objective: Pedicle screw-based constructs are the standard of surgical management in AIS. Several manufacturers have developed navigation systems utilising intraoperative 3D imaging to improve screw placement accuracy. However, concerns remain regarding intraoperative radiation exposure utilising these systems compared to traditional techniques. The aim of this study was to evaluate our experience of 3D intraoperative imaging compared to techniques utilising 2D fluoroscopy for pedicle screw placement in cases of posterior spinal fusion (PSF) for AIS.

Methods: This was a single-centre, retrospective analysis of cases undergoing PSF for AIS using 3D navigation or freehand screw insertion techniques. The two groups were matched for curve type, curve magnitude, implant density and fused levels. We compared the correction achieved, intraoperative radiation exposure, operating time and rates of intraoperative screw repositioning.

Results: A total of 52 cases were identified (26 navigated and 26 freehand). No significant differences were observed in baseline characteristics between the two groups. There were no significant differences observed in correction achieved between groups; however, mean radiation exposure in the navigated cases was approximately 11 times higher. Operative time was significantly longer in the navigated group but there was a significant reduction in requirement for intraoperative screw repositioning using navigation at 0.2% versus the freehand group at 1.5%.

Conclusions: Our early experience of intraoperative 3D imaging for navigated implant insertion for AIS has shown equivalence to freehand techniques in achieved correction, with fewer changes in intraoperative screw positioning at the expense of significantly increased overall radiation exposure and procedure duration. Methods: II.