The Course of Non-Surgical Management of Burst Fractures with Intact Posterior Ligamanteous Complex (PLC): An MRI Study

Material and Methods: Fifteen consecutive neurologically intact patients with burst fractures were managed nonoperatively with the indication based solely on the integrity of PLC determined by MRI. Correction of deformity and stabilization with a total body cast under sedation were the mainstays of treatment. Patients were mobilized the next day and casts were removed at the end of the 3rd month f/up with no further external stabilization. Local kyphosis (LK), sagittal index (SI) and percent of compression of body height (ABH) were measured on pre-treatment, post-treatment, 3rd month and latest f/up xrays. All patients’ preoperative and latest f/up MRI studies were analyzed to examine discs adjacent to and neighboring the fractured levels. Patients’ perception of function, pain and appearance were analysed using Likert Questionnarre.

Results: There were 8 female and 7 male patients with an average age of 28 (range 15-49) years. Average f/up was 31 (24- 51) months. Twelve patients had Denis type B while 3 had type A fractures.

Table1. The results of x-ray analysis.

Pre-treatment MRI analysis revealed changes in the shape of the discs (narrowing or herniation into the body) with no change in the signal intensity of nucleus pulposus(NP) in 8 of the cranial and in 5 of the caudal adjacent discs. On followup MRI, there was only one intact disc with a normal shape cranially. All others had height loss but only one had complete loss of signal intensity. Caudally, 4 additional discs had changes in shape without any gross changes in signal intensity of NP. None of the neighboring discs had changes in shape or signal intensity at the time of injury or at latest f/up. Average score of function, pain and appearance were 4, 4 and 3.5 respectively at the latest f/up. All patients returned to original work at 3.6 (range 1-9) months on average and all were satisfied with their treatment. Conservative treatment based on integrity of PLC is controversial, probably due to poor evaluation by clinical and indirect radiographic findings.

Conclusion: An intact PLC may not prevent loss of correction gained by non-surgical management of burst fractures. Significant loss occurs in the first 3 months despite external stabilization. However, the magnitude of residual deformity usually remains close to the original deformity. Although changes in the shape of adjacent discs occur due to trauma and/or natural course, significant loss in signal intensity of nucleus pulposus is very unlikely. Patient outcome seems to be highly satisfactory despite residual deformity.