Does three-dimensional preoperative planning improve accuracy of pedicle screw insertion

Abstract

Aim: To evaluate the superiority of preoperative three-dimensional (3D) CT-based planning over two-dimensio nal (2D) planning in terms of pedicle screw placement accuracy. Materials and methods: In a virtual environment, three surgeons placed pedicle screws in the lumbar region of eight patients in the 2D group after conventional 2D planning. In the 3D group, they placed pedicle screws after 3D CT-based planning. Trajectory angles, distance of the wall breach and distance of the screw entry point deviation were recorded after virtual surgeries. Results: In the 2D group, 69 screws (28.8%) penetrated the pedicle wall and 37 screws (15.5%) penetrated the pedicle wall in the 3D group. Comparing these two groups, preoperative 3D planning showed a significant advantage (P = 0.003). In the 2D group, the mean angle of the screw trajectory preoperatively calculated was 19.65 ?? 6.35??, and the mean angle of the inserted screws was postoperatively measured at 20.79 ?? 5.95??. In the 3D group, the mean angle of the screw trajectory calculated preoperatively was 20.18 ?? 5.67??, and the mean angle of the inserted screws postoperatively was 20.07 ?? 5.85??. The screws were inserted in the similar orientation comparing to preoperative planning in the 3D group (P = 0.655), but a similar orientation could not be obtained postoperatively in the 2D group (P ??? 0.001) for all levels. Conclusion: Preoperative 3D planning improves accuracy by helping determine the pedicle screw entry point and direction.