Study design: Nine patients with thoracolumbar burst fractures associated with horizontal fractures in the posterior column were studied retrospectively.
Objectives: To clarify the clinical and radiographic findings and evaluate the postoperative results for this type of fracture.
Summary of background data: It is not well recognized that burst fractures occasionally are accompanied by horizontal fractures of the posterior column such as those that result from seatbelt-type injuries. This type of burst fracture differs from flexion-distraction injuries combined with burst fracture, which are accompanied by horizontal fractures not only in the posterior but also in the middle column. Radiographic features of these two different types of injuries are very similar to each other, and their differentiation in diagnosis and treatment has not been recognized clearly.
Methods: Patients were reviewed using a combination of clinical records, follow-up examination, and radiographic data (computed tomography [CT], plain radiographs, and tomographs). Anterior spinal fusion was performed in eight patients using the Kaneda device (Mizuhoika Tokyo, Japan), and one was treated by posterior fusion with pedicle screw fixation. The average follow-up period was 4 years.
Results: Patients with fractures of this type represented 21% of the 48 patients with thoracolumbar burst fractures. The injury was sustained by falling in all nine patients. All of the burst fractures were Denis' type B. The horizontal fracture was located at the lamina and spinous process in the posterior column of the upper vertebra adjacent to the involved vertebra in all nine patients. The integrity of the ligamentous structures of the middle column, such as the posterior longitudinal ligament, the periosteum, and the outermost anulus, was confirmed at surgery in eight patients, although not in the patient who underwent posterior fusion. One patient required surgery because of progression of kyphotic deformity during conservative treatment. Solid fusion with no complications was noted in all patients.
Conclusion: This type of burst fracture is not accompanied by ligamentous injuries because of distraction force in the middle column, which is not present in flexion-distraction injuries, but it seems to be more unstable than burst fractures with no horizontal splitting of the posterior column and requires surgical stabilization.