The accuracy of intraoperative O-arm imaging in assessing thoracolumbar pedicle screws placement

Objectives: Pedicle screw fixation in spine surgery is often considered the gold standard due to its biomechanical advantages. Complications such as screw misplacement may arise during the procedure, leading to severe consequences. Intraoperative 2D/3D imaging system images or a post-operative computed tomography (CT) scan are employed to assess this. This study aimed to determine the agreement between these two imaging systems to evaluate the placement of transpedicular screws using the Zdichavsky classification. Methods: Image data from the intraoperative 2D/3D imaging system and CT scans of patients undergoing spine surgery at the neurosurgery department were collected from March 2021 to May 2022. The position of transpedicular screws was evaluated using the Zdichavsky classification. Results: Images from 19 patients, 7 males (36.84%) and 12 females (63.16%), aged 28-77 years, were gathered. A total of 131 transpedicular screws were evaluated, ranging from 4 to 10 screws per patient. In the post-operative CT scan, 123 screws were classified as type Ia (93.89%), seven screws as type Ib (5.34%), and one screw as type IIb (0.76%). With the navigation system, 125 screws were classified as type Ia (95.42%), five as type Ib (3.82%), and one screw as type IIb (0.76%). Conclusion: It was demonstrated that intraoperative 2D/3D system images can be used to assess screw placement without the need for post-operative studies such as CT scans.