Indirect spinal canal decompression in patients with thoracolumbar burst fractures treated by posterior distraction rods.

The ability of posterior distraction instrumentation to produce indirect reduction of retropulsed bone fragments was studied in 44 patients with thoracolumbar burst fractures. Using the Denis Classification, two predominate fracture types were identified: 13 patients had type A and 29 had type B fractures. Two others had Denis type D fractures. Spinal canal stenosis was reduced from a preoperative mean of 65% to 32.8% postoperatively. Denis type A fractures had significantly better reduction of 62.5% pre- to 19.2% postoperatively. Denis type B fractures reduced from 66.3% pre- to 38.9% postoperatively. The initial kyphotic deformity and the loss of vertebral height did not influence results of indirect decompression. Neurologic function at follow-up correlated with preoperative canal stenosis, but did not correlate with residual stenosis after instrumentation. This study demonstrated that posterior distraction instrumentation can achieve approximately 50% reduction in canal stenosis and that results will be influenced by fracture morphology.