[Significance of the intervertebral disk in failed reduction of surgically stabilized fractures of the truncal spine].

In 112 patients with a traumatic fracture of the thoraco-lumbar spine operatively treated with different dorsal stabilization techniques from 1983 to 1988, the frontal and sagittal planes of the spine were analyzed over a follow-up period of 5 years. In 14 cases Harrington instrumentation was used, in 81 cases, transpedicular plates, and in 17 cases, a fixateur interne. With regard to the frontal plane the overall loss of correction was 2.3 degrees: with Harrington stabilization 0.7 degrees, with fixateur interne 2.6 degrees, and with plate fixation 3.7 degrees. In the sagittal plane the height of the damaged spinal segment and the kyphotic angulation were determined. The mean height loss after operative repositioning was 12%. With Harrington stabilization it was 16%, with plate fixation 12%, and with fixateur interne 9%. Kyphosis of 9.6 degrees was determined before surgery, and 0.9 degrees after. The angle subsequently deteriorated, reaching 12.6 degrees by the end of 5 years. The loss of correction was 9.3 degrees in the fixateur interne group, 10.9 degrees in the Harrington stabilization group, and 15 degrees in patients in whom plate fixation had been performed. The cause of deterioration was destruction of the invertebral disc in 66% of cases, and angulation of the fractured vertebral body in only 33%. Only in the first 2 years after operation was loss of reposition in the vertebral body observed. In conclusion, stabilization should be complemented by removal of the damaged adjacent disc and intercorporeal autogenous bone grafting from the dorsal or ventral approach.