Course of nonsurgical management of burst fractures with intact posterior ligamentous complex: an MRI study.

STUDY
DESIGN: Prospective study.
OBJECTIVES: To evaluate the results of nonsurgical management of burst fractures with intact posterior ligamentous complex and to investigate the effect of trauma and/or residual kyphotic deformity on adjacent and next adjacent (neighboring) discs. SUMMARY OF BACKGROUND DATA: Conservative treatment based on integrity of posterior ligamentous complex is controversial, probably because of poor evaluation by clinical and indirect radiographic findings. Degenerative changes in the adjacent discs due to trauma and/or residual kyphotic deformity is a common expectation.
MATERIAL AND METHODS: Fifteen consecutive patients who were intact neurologically with burst fractures (T11-L2) were treated nonsurgically with the indication based solely on the integrity of posterior ligamentous complex 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 third month follow-up period with no further external stabilization. Local kyphosis angle, sagittal index, and percent of compression of anterior body height were measured on pretreatment, post-treatment, third month, and latest follow-up radiographs. All of the preoperative and latest follow-up MRI studies of the patients were obtained to examine the discs adjacent and next adjacent to the fractured levels. The self-reported perceptions of the patients of function, pain and appearance were analyzed using the Likert Questionnaire.
RESULTS: There were eight female and seven male patients with an average age of 28 (range, 15-49) years. Average follow-up period was 31 (range, 24-51) months. Average local kyphosis angle was found to be 16.5 degrees (0-34 degrees ) after trauma. It was corrected to 5 degrees (range, 19-25 degrees ) and deteriorated to 14.6 degrees (range, 2-25 degrees ) at the third month and to 17 degrees (range, 2-29 degrees ) at the final follow-up review. There was a similar tendency for both sagittal index and percent anterior body height. The pretreatment 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 in eight of the cranial and four of the caudal adjacent discs. On follow-up 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, two additional discs had changes in shape without any gross changes in signal intensity of nucleus pulposus, whereas two had changes in signal intensity without change in shape. Only two of the next adjacent discs had changes in shape or signal intensity at the time of injury or at latest follow-up review. Average score of function, pain, and appearance were 3.9 (range, 3-5), 3.7 (range, 2-5), and 3.7 (range, 2-5), respectively, at the latest follow-up review. All patients were back at work in 3.6 (range, 1-9) months on average and all were satisfied with their treatment.
CONCLUSIONS: The present study revealed that an intact posterior ligamentous complex might not prevent loss of correction gained by nonsurgical 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 initial 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 unlikely. Patient outcome seems to be highly satisfactory despite residual deformity.