Does Size Matter? Evaluating the Impact of Intermediate Screw Length in Short-Segment Fixation of Thoracolumbar A3–A4 Fractures

<b>Background</b>: Short-segment posterior fixation with intermediate pedicle screws is widely used for thoracolumbar junction (TLJ) burst fractures. However, the optimal penetration depth of intermediate screws remains controversial. The aim of this study was to evaluate whether intermediate screw penetration depth influences radiographic alignment and functional outcomes at 12 months following short-segment posterior fixation of AO Spine A3-A4 thoracolumbar burst fractures. <b>Methods</b>: This retrospective cohort study included 105 patients with AO Spine A3-A4 TLJ burst fractures treated between 1 January 2019 and 31 December 2022. All patients underwent short-segment posterior stabilization with intermediate screws at the fracture level. Penetration depth was categorized as either <50% (Group A) or ≥50% (Group B) of vertebral body depth. Radiographic parameters (kyphotic deformity, segmental kyphosis, sagittal index, anterior vertebral body height) and clinical outcomes (Visual Analog Scale and Oswestry Disability Index) were evaluated preoperatively and at 12 months. <b>Results</b>: Both groups demonstrated significant postoperative improvement in radiographic alignment and clinical outcomes. No statistically significant differences were detected between groups in kyphotic correction, loss of correction, pain reduction, disability scores, operative time, length of stay, or complication rates at 12 months. <b>Conclusions</b>: Within the limitations of this retrospective study, intermediate screw penetration depth did not significantly influence radiographic or clinical outcomes at 12 months. Screw length selection may therefore depend on anatomical considerations and surgeon preference rather than expected differences in clinical performance.