Stabilisation of fractured thoracic and lumbar spine with Cotrel-Dubousset instrument.

OBJECTIVE To evaluate the effectiveness of 2 different types of Cotrel-Dubousset instrument systems in stabilising thoracolumbar and lumbar spine fractures. METHODS Between January 1989 and December 1993, 45 fractures in 42 patients with unstable fracture or fracture dislocation of the thoracolumbar and lumbar spines were randomly assigned to 2 surgical treatments with Cotrel-Dubousset instrumentation-using either a long segment (Group 1) or a short segment (Group 2)-and short posterolateral fusion. RESULTS Consolidation of the fractured vertebral body and posterolateral fusion were achieved at a mean time of 4.5 months; fusion rates were 75% in Group 1 and 83% in Group 2. The average collapses of anterior vertebral body height in Group 1, in the immediate postoperative period and at the final follow-up, were 15% and 17%, respectively; and in Group 2, the figures were 16% and 24%, respectively. The correction of vertebral height and kyphosis at the last follow-up were lost more in Group 2 (5.7 degrees ) than in Group 1 (4.4 degrees ). There were neurological recoveries in 6 of the 9 cases of incomplete paraplegics, including complete recovery in 5, and one-Frankel grade increase in one. There were 15 instrument failures in 12 patients, including screw breakage in 3 Group 1 cases and 6 Group 2 cases. The plug dislodged in 3 Group 1 cases, and the hook dislodged in 3 Group 2 cases. In other words, instrument failures were more common in Group 2. CONCLUSION Cotrel-Dubousset stabilisation of the fractured spine achieves fracture consolidation, but does not maintain the restored height and sagittal curve completely until fusion. The long rod and short fusion construct was more effective for all fracture types than was the short rod and fusion construct, although it leads to wider immobilisation of normal segments.