Anatomical and biological reconstruction of traumatic complete burst fractures of the thoracolumbar vertebrae using pedicle fixation combined with stent-armed kyphoplasty and intracorporeal bone grafting: technique rationale, 7-year experience and clinical, imaging, and histological outcomes.

BACKGROUND: The optimal management of thoracolumbar burst fractures remains controversial. Growing evidence suggests that anatomical vertebral body restoration may be important for restoring structural integrity, load-bearing capacity, and spinal function. The objective of this study was to evaluate the clinical, imaging, and histological outcomes of novel surgical technique for anatomical and biological vertebral body reconstruction in acute traumatic complete burst thoracolumbar fractures. METHODS: This prospective study included 32 patients with acute traumatic thoracolumbar complete burst fractures without neurological deficits treated using a novel vertebral body reconstruction technique combining pedicle fixation, stent-armed kyphoplasty, and intracorporeal allogeneic bone grafting. Clinical outcomes [Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Patient Global Impression of Change (PGIC)] and imaging parameters (vertebral body heights, sagittal alignment, and posterior wall retropulsion) were evaluated. In addition, intra-stent bone biopsies were performed in 23 patients to assess allograft incorporation and healing prior to removal of the posterior instrumentation. RESULTS: Mean follow-up was 4.39±1.46 years (range, 2-7 years). There was a statistically significant improvement in all clinical and functional parameters evaluated between preoperative period and the final follow-up. All vertebral height parameters increased postoperatively, with partial loss of correction over time. At end of follow-up, a statistically significant difference compared with preoperative values was observed for posterior sagittal and left coronal heights; a trend toward significance was noted for anterior sagittal and median coronal heights, and no significant difference was found for median sagittal and right coronal heights. Regarding posterior wall retropulsion, a statistically significant decrease was observed throughout follow-up. Regarding both sagittal angles, a marked postoperative correction was achieved, followed by progressive loss of correction over time. Computed tomography demonstrated imaging signs of vertebral body healing in all patients, while histological analysis demonstrated viable incorporated allograft in 22 of 23 biopsied patients, characterized by trabecular bone containing osteocytes within lacunae and cellular bone marrow with identifiable sinusoids and erythrocyte-containing capillaries. Greater anterior sagittal, median sagittal, and median coronal vertebral body heights were negatively correlated with VAS and ODI scores at different time points. CONCLUSIONS: The favorable clinical, imaging and histological outcomes observed at mid-term follow-up, support the feasibility of this percutaneous transpedicular circumferential stabilization technique for traumatic complete thoracolumbar burst fractures, demonstrating encouraging results for biological osseous vertebral body reconstruction reinforced by a metallic internal sustentaculum. The observed clinico-morphological correlations suggest that more effective restoration of vertebral height in both the sagittal and coronal planes is associated with improved clinical and functional outcomes, thereby reinforcing the importance of anatomical restoration in vertebral compression fractures. This technique represents a minimally invasive approach to vertebral body reconstruction, with promising outcomes in severe fractures; however, comparative studies with other techniques are needed to determine its relative efficacy and potential advantages.