Spontaneous remodeling of the spinal canal after burst fractures of the low thoracic and lumbar region.

A retrospective study was done on five adult patients in whom burst fractures of the low thoracic and lumbar spine were associated with intracanalar displacement of a large bony fragment. In one case two vertebrae were involved. Three of these patients presented with neurologic damage of different degrees. All but one underwent operative posterior stabilization by Harrington rods and bone autografts. Although no surgical decompression was performed, they showed gradual neurologic recovery at the follow-up, which is still incomplete in only one, initially paraplegic patient. In comparing the initial computed tomography scans of the five patients with those taken 1 1/2-5 years later at the same level, it was found that a process of total or subtotal resorption of the retropulsed fragment had occurred in all patients, with spontaneous remodeling of the spinal canal. These findings agree with the recent reports of other authors and provide the orthopedic surgeon with a new argument in favor of the possible conservative treatment of these severe, potentially unstable fractures. In most of the cases, and especially in those without neurological compromise, surgical reduction or surgical removal of the intraspinal fragment is not necessary. We believe that loss of mechanical loading and rhythmic respiratory oscillations in cerebrospinal fluid pressure are both important factors in the mechanism of bone resorption.