腰椎单侧椎弓根螺钉固定并椎间融合的生物力学研究

Biomechanical Analysis of Unilateral Pedicle Screw Fixation and Interbody Fusion in Lumbar Spine

目的：分析腰椎单侧椎弓根螺钉固定并椎间融合的生物力学性能,为临床应用提供理论依据.方法：采用6具新鲜成人脊柱腰骶段（L3～S1）标本,分别测试8 Nm载荷情况下完整标本（正常组）、单侧椎弓根螺钉内固定（螺钉组）、单侧椎弓根固定并单侧椎板减压（减压组）和单侧椎弓根螺钉固定并椎间融合（融合组）等四种状态下固定椎体的活动范围,并比较其生物力学的稳定性.结果：在8 Nm的纯力矩偶载荷下,减压组的屈伸、侧弯和旋转等3种活动范围均最大,其余按活动范围由大到小依次为正常组、螺钉组和融合组,4组间差异有统计学意义（P＜0.05）;螺钉组和融合组的3种活动范围组间差异无统计学意义（P＞0.05）,但均小于正常组（P＜0.05）.结论：单侧椎弓根螺钉固定并椎间融合可以提供良好的生物力学稳定性,可作为腰椎退行性疾病的治疗选择.

Objective：To comparatively analyze biomechanical stability of unilateral lumbar pedicle screw fixation and interbody fusion, in order to provide theoretical basis for clinical application. Methods：Six specimens of fresh human lumbosacral spine （L3 -S1 ） were tested under 8Nm load, the range of activities （ ROM ） of fixed vertebral body in four different states ： intact, unilateral pedicle screw fixation, unilateral pedicle screw fixation and unilateral laminectomy, unilateral pedicle screw fixation and interbody fusion were meas- ured. Biomechanical stability was compared among the above four groups. Results： Under 8Nm pure torque load, the ROM of flexion and extension, lateral bending and rotation conditions was the largest in unilateral pedicle screw fixation and unilateral laminectomy group . The remaining decreasing order were normal group, unilateral pedicle screw group and the unilateral pedicle screw fixation and interbody fusion group. Difference between the four groups was statistically significant（ P 〈 0.05 ）. The ROM of unilateral pedicle screw group and unilateral pedicle screw fixation and interbody fusion group were significantly lower than the normal group, but no significant difference between the two groups（ P 〉 0.05 ）. Conclusions：Unilateral pedicle screw fixation and interbody fusion can provide satisfactory biomechanical stability. It can be used in spine fusion in lumbar degen- erative diseases.