Intermediate screw placement improves initial radiographic alignment but not clinical outcomes following long-segment fixation for thoracolumbar fractures.

BACKGROUND

The role of intermediate screws in long-segment posterior fixation for thoracolumbar fractures remains controversial. This study aimed to evaluate their effectiveness in improving alignment, maintaining correction, and reducing complications.

METHODS

This retrospective comparative study included 91 patients with unstable thoracolumbar burst fractures (T11-L2) treated between 2014 and 2022. Patients were divided into two cohorts: Group A (n=61), who underwent long-segment fixation with intermediate screws inserted at the fracture level, and Group B (n=30), who received conventional fixation. Radiological outcomes, including vertebral compression angle (VCA) and anterior/posterior vertebral body height (ABH/PBH), intraoperative parameters (operative time and fluoroscopy use), clinical pain scores assessed using the Visual Analog Scale (VAS), and complications were analyzed. Statistical comparisons were performed using t-tests and chi-square tests.

RESULTS

Both groups demonstrated significant postoperative improvements in VCA and vertebral body height (p<0.0001). Group A achieved superior early correction of VCA compared with Group B (4.78°±3.47 vs. 6.82°±4.02, p=0.014), and this difference remained significant at the two-year follow-up (5.67°±3.08 vs. 8.59°±3.76, p=0.0005). Although correction loss was lower in Group A (1.22°±1.13 vs. 1.95°±2.12, p=0.122), the difference was not statistically significant. Group A required longer operative times (160.25±19.4 vs. 150.17±26.9 minutes, p=0.044) and greater fluoroscopy exposure (26.38±2.3 vs. 20.00±2.13, p<0.001). No significant differences were observed between groups in preoperative or follow-up VAS scores (p>0.05).

CONCLUSION

Placement of intermediate screws in long-segment constructs was associated with significantly enhanced restoration and maintenance of radiographic alignment in patients with thoracolumbar fractures, although it required longer operative time and increased fluoroscopy use. Clinical pain outcomes were comparable between groups. These findings suggest that intermediate screw placement may provide biomechanical and radiographic advantages in selected cases where optimal anatomical restoration is prioritized. This technique was associated with improved initial and long-term radiographic alignment, at the cost of longer operative time and greater radiation exposure, but did not improve pain outcomes. However, the non-random assignment of patients according to surgeon preference should be considered when interpreting these results.