Intraoperative accuracy of O-arm navigated pedicle screw placement in the thoracic and lumbo-sacral regions of the spine - does localization matter?

Aim: The aim of the current study was to determine the intraoperative accuracy of pedicle screw placement using a 3D CT-assisted navigation system with an O-arm in the thoracic, lumbar, and sacral regions of the spine, as well as to investigate the effect of localization on pedicle screw positioning accuracy. Materials and methods: This single-center retrospective study was carried out on 180 patients who had open navigated pedicle screw implantation in the sacral, lumbar, and thoracic regions of the spine at our facility between January 2017 and December 2024. All patients underwent intraoperative scanning with the O-arm before and after screw placement and after screw trajectory correction in case of malpositioning. Additionally, early postoperative CT imaging was uniformly performed. The accuracy of screw placement was assessed by an experienced radiologist and a neurosurgeon using the Gertzbein-Robbins Grading Scale.

Results

Intraoperative post-implantation O-arm CT scans revealed 44 (3.5%) malpositioned screws out of 1257 implanted pedicle screws, resulting in 96.5% Grade A screw placement accuracy. Clinically, 98.2% (1234) of the pedicle screws were properly positioned (Grade A + B). Screw placement in the thoracic region correlated with significantly higher grades of malpositioning: Grade C (ρ=0.315, p<0.001) and Grade D (ρ=0.191, p=0.010), especially in the upper thoracic spine.

Conclusion

Image-guided 3D O-arm spinal navigation assistance during pedicle screw implantation can lower the risk of screw malpositioning, thus reducing the need for subsequent revision surgery, especially in the upper thoracic segment of the spine.