RESUMO
STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate the significance of the intraoperative postural reduction for kyphotic deformity in unstable burst fracture and confirm the relations of postural reduction and the final correction after loss of correction by posterior instrumentation. SUMMARY OF LITERATURE REVIEW: The loss of kyphotic correction after instrumentation in unstable burst fracture is found. Some methods have been developed to reduce the loss of correction. MATERIALS AND METHODS: 24 short-segment pedicle screw instrumentations in the patients with a unstable burst fracture were performed. We measured sagittal index, wedge angle of vertebral body and anterior vertebral height preoperatively, intraoperatively, postoperatively and at final follow-up. RESULTS: Sagittal index was 20.2 degrees preoperatively, 7.5 degrees intraoperatively, 0.9 degrees postoperatively and 7.2 degrees at final follow-up, so the loss of correction was 32.6%. Wedge angle of vertebral body was 20.3 degrees preoperatively, 10.1 degrees intraoperatively, 6.8 degrees postopera-tively and 9.4 degrees at final follow-up, so the loss of correction was 19.3%. Anterior vertebral height was 57.0%, 79.3%, 85.0%, and 78.8% respectively, so the loss of correction was 22.1%. The loss of correction occurred more in the disc space and less in the vertebral body itself. Postural reduction corrected 63% of sagittal index, 50% of wedge angle of vertebral body and 52% of anterior vertebral height. CONCLUSIONS: Postural reduction corrected kyphotic deformity appropriately. The correction by posterior instrumentation in unstable burst fracture was lost in some amount. The final correction was similar to the one by postural reduction. It is important to obtain the maximum postural reduction intraoperatively to prevent kyphotic deformity caused by loss of correction after surgery.