Long segmental fixation with TSRH posterior instrumentation for 19 patients who had unstable thoracolumbar fracture was performed between October 1992 and April 1995. The patients were followed for an average of 22 months. Measurements of the deformity angle, kyphosis, vertebral height, and the intervertebral angle were made. The patients were divided into 2 groups according to configurations of instruments for lower segmental fixation. For one group, only hooks were used, and for the others group pedicular screws and lateral offset hooks were used together at the same segment. Therefore, the purpose of this study is to anlyze the correctability following long segmental fixation and to compare one segmental fixation using both screws and lateral offset hook systems with two segmental fixation using hook systems for distal fixation. There was an overall correction of kyphosis at follow-up of 6.9degrees (27.1%) after a loss of 4.3degrees from operative correction. Overall correction of deformity angle was 8.2degrees (32.2%). Loss of vertebral height at final follow-up was 4.4%. And loss of intervertebral angle was 2.0degrees at follow-up. There was no difference of overall results between the hook group and the pedicular screw with lateral offset hook group. However, there was a significant improvement of the correction of kyphosis and restoration of vertebral height in patients who underwent operation within 7 days after injury, as compared to delayed operation. Therefore, the timing of surgery is the most important factor in order to correct the deformity caused by unstable thoracolumbar fractures. There was no significant loss of correction and no metallic failure. Therefore, rodding long with the method of one segment distal fixation using screws and lateral offset hook together can provide excellent correctability, maintenance of correction, preservation of distal lumbar joints, prevention of implant failure and complication.