Effects of two-levels, four-levels, and four-levels plus offset-hook posterior fixation techniques on protecting the surgical correction of unstable thoracolumbar vertebral fractures: a clinical study

Following fracture reduction and initial reconstitution of spinal alignment, loss of correction over time is frequently observed after posterior instrumentation. The degree of stability to provide a favorable environment for protection of initial correction is not known. A total of 36 patients with thoracolumbar burst fractures were divided into three groups. Group 1 included 12 patients treated by two-levels fixation, group 2 included ten patients treated by four-levels fixation, and group 3 included 14 patients treated by four-levels plus offset-hook fixation. Preoperative, early postoperative, and 1-year follow-up lateral spinal radiographs were evaluated by measuring the local kyphosis angle (LKA), the percentage of anterior body-height compression (%ABC), and the sagittal index (SI). For protecting the initial correction of LKA, group 3 was superior to the other groups (P<0.05). For protecting the initial correction of %ABC, groups 2 and 3 were the same (P>0.05), and these two groups were superior to group 1 (P<0.05). For protecting the initial correction of SI, group 3 was superior to group 1 (P<0.05), and the other groups were the same (P>0.05). Group 1 had a significant failure rate compared to the other groups (P<0.05). Two-levels fixation was the least stable system, and four-levels fixation plus offset hook was the most stable.