Individual Navigation Templates for Subcortical Screw Placement in Lumbar Spine

Subcortical screw placement is currently performed using frontal view fluoroscopy or intraoperative O-arm navigation system. The emergence of a novel technique for spinal navigation based on individual navigation templates created using 3D printing technology determines the need to study their safety and effectiveness in subcortical implantation. The aim of the study was to evaluate and compare the efficacy of subcortical implantation of pedicle screws in the lumbar spine using individual navigation templates versus intraoperative fluoroscopy. Materials and Methods The study was based on the analysis of treatment results in 39 patients who underwent surgery with subcortical implantation of 130 screws using the MidLIF technique. In group 1, navigation templates were used, in group 2 — intraoperative fluoroscopic control. Comparative analysis of implantation correctness and time, the total operation time, and radiation load was performed. Results The mean distance between the screw and the cortical plate recorded in the groups ranged within 1.20–3.97 mm, without statistically significant difference (p>0.05). The mean time of pedicle screw implantation was 137.0 [115.25; 161.50] s in group 1 and 314.0 [183.50; 403.25] s in group 2. The total operation time was reduced from 173.0 [155.0; 192.25] min in group 2 to 119.0 [108.0; 128.75] min in group 1. The average of 1.0 [1.0; 2.0] X-ray image was performed to place one screw in group 1, while it was 12.0 [10.0; 13.25] in group 2. The differences between the groups in terms of implantation time and radiation load were statistically significant (p<0.05). Conclusion Compared with intraoperative fluoroscopy, the use of individual navigation templates for subcortical implantation of pedicle screws provides their correct positioning with a significant reduction in both operation time and radiation load at similar safety.