Isolated unstable burst fractures of the fifth lumbar vertebra: functional and radiological outcome after posterior stabilization with reconstruction of the anterior column: About 6 cases and literature review.

Introduction: L5 burst fractures represent a small percentage of all spine fractures. Treatment strategy has not yet been standardized. Anatomical features and their biomechanical characteristics create fracture patterns which differ from those at the thoracolumbar junction. The objective of this study was to evaluate L5 burst fracture surgical treatment outcomes after posterior stabilization and reconstruction of the anterior column.

Patients And Methods: Six patients with fifth lumbar isolated unstable burst fractures were analyzed. Medical records, radiographs, and clinical scores were obtained. The results were evaluated based on restoration of vertebral body height, spinal lordosis/kyphosis, canal compromise and sagittal alignment at several phases of treatment.

Results: No patient showed neurologic deterioration, regardless of treatment. The median preoperative anterior vertebral height was 41mm and postoperative was 48mm. The median preoperative kyphotic angle as measured by Cobb angle (local and regional) was 21.5 degrees and 33 degrees which improved respectively by 7.5 and 5.5 degrees following instrumentation. The median amount of backward protrusion of bony fragment into the canal was measured at 67% preoperatively and at 35% postoperatively. There were no pseudarthrosis and anterior arthrodesis solid fusion was visible in all cases. There were a sagittal alignment restoration. At one year of follow up, fusion was obtained in all the cases, all patients had minimal to moderate disability using Oswestry Disability Index. The ability to return to work revealed a good-to-excellent long-term result.

Discussion: The results of treatment of 5th lumbar unstable burst fractures with posterior stabilization and reconstruction of the anterior column show benefit on durable functional outcome, spine stabilization and radiologic parameters.

Level Of Evidence: IV, retrospective study.