BACKGROUND Thoracolumbar burst fractures with high Load Sharing Classification (LSC) scores are mechanically unstable and associated with severe vertebral comminution and failure risk after short-segment fixation. This study evaluated outcomes of long-segment posterior fixation combined with intracanal bone fragment compaction as an indirect means of supporting the anterior column. METHODS This retrospective study analyzed prospectively collected data from 121 consecutive patients with unstable thoracolumbar burst fractures (T10-L2) and LSC scores >6. All patients underwent open long-segment posterior instrumentation, decompression, and compaction of retropulsed intracanal bone fragments. Radiological outcomes included Cobb angle, percentage of anterior height compression (PAHC), vertebral body compression ratio (VBCR), and spinal canal compromise. Neurological recovery was assessed using the American Spinal Injury Association (ASIA) scale, and functional outcomes using the Oswestry Disability Index (ODI). RESULTS The cohort included 70 men and 51 women, with a mean age of 37.2 years and follow-up of 23.2 months. At final follow-up, 58.7% (95% CI 49.8-67.1%) achieved ASIA grade E. Significant improvements were observed in VBCR, PAHC, Cobb angle (15.6° to 7.9°; p = 0.008), and spinal canal compromise (65.2% to 8.7%; p < 0.001). Mean ODI improved from 59.4 to 8.4 (p < 0.001). CONCLUSION Long-segment posterior fixation with intracanal bone fragment compaction was associated with favorable short- to mid-term neurological, functional, and radiological outcomes. Prospective comparative studies with CT-based fusion assessment, standardized safety reporting, and longer follow-up are required to confirm effectiveness and durability.
