棘上韧带与腰椎融合术后相邻节段退变的相关性研究

The correlation analysis between supraspinal ligament and adjacent segment degeneration after lumbar fusion

目的探索棘上韧带对预防腰椎融合术后相邻节段退变的重要意义,为提高腰椎融合的手术后效果提供理论和数据基础。方法选取健康成年新西兰大白兔20只,随机分为实验组和对照组,两组均在全身麻醉下行前路暴露腰5/6(L_(5/6))椎体并予L_(5/6)椎体U形钉固定完成模型,实验组暴露L_(4/5)棘上韧带并切除,对照组不做任何处理。比较两组大白兔在手术后相邻脊柱节段的退行性病变和病理结果上的差异性。结果两组实验对象在术前临近节段的椎间隙高度和活动范围上差异均无明显的统计学意义(P>0.05),对照组对象仅在术后Cobb角上明显大于对照组[(50.7±6.2)°vs.(45.3±5.1)°,t=2.131,P=0.047],实验组临近节段术前术后的椎间隙活动范围有明显改变[L_(4/5):(5.1±0.8)°vs.(4.2±0.7)°,t=2.811,P=0.020;L_(6/7):(4.5±0.7)°vs.(3.6±0.6)°,t=2.513,P=0.033],术后Cobb角也明显大于术前[(45.3±5.1)°vs.(40.2±4.4)°,t=3.207,P=0.011]。共有12只兔子发生腰椎椎间盘的退行性病变,3级病变均发生实验组,两组对象在病变分级上差异有统计学意义(P<0.05),退行性病变主要的病理类型为黏液样变性,严重者可有髓核区坏死的形成。Logistics回归分析显示仅有切除棘上韧带是术后腰椎间盘退行性病变的主要影响因素(OR=32.652,95%CI=1.684~632.948,P=0.021)。结论腰椎融合术中保留临近节段的棘上韧带可以明显增加临近节段椎间隙活动范围和Cobb角,并且是发生术后椎间盘退行性病变的保护因素。

Objective To explore the significance of supraspinal ligament on preventing adjacent segment degeneration after lumbar fusion and provide theoretical and statistical basis for lumbar fusion. Methods Twenty healthy New Zealand rabbits were selected as the research objects and divided into two groups. There were 10 rabbits in the experimental group and 10 rabbits in the control group. All rabbits received lumbar 5/6 exposed and vertebral body fixation model under general anesthesia through the anterior path. Rabbits in the experimental group had the supraspinal ligament of lumbar 5/6 exposed and resected. Rabbits in the control group only had the supraspinal ligament of lumbar 5/6 exposed but without resection. The degeneration and pathologic findings of intervertebral disc were compared between two groups. Results There were no differences in adjacent segment disc height and space angulation between two groups. The lordosis angle of L3/S1 using Cobb′s method in the control group was higher than that in the experimental group after lumbar fusion[(50.7±6.2)° vs.(45.3±5.1)°,t=2.131,P=0.047]. The space angulation of L_(4/5)and L_(6/7)after lumbar fusion both had a significant improvement than that before lumbar fusion in the experimental group[L_(4/5):(5.1±0.8)° vs.(4.2±0.7)°,t=2.811,P=0.020;L_(6/7):(4.5±0.7)° vs.(3.6±0.6)°,t=2.513,P=0.033]. So did the Cobb′s angle in the experimental group[(45.3±5.1)° vs.(40.2±4.4)°,t=3.207,P=0.011]. There were 12 rabbits with degeneration of adjacent intervertebral disc. The degeneration on third level all happened in the experimental group. There were significant differences in disc degeneration level between two groups. The main pathological type was mucous degeneration. The necrosis occurred in the nucleus pulpit in the severe cases. Logistics regression showed that the removement of supraspinal ligament was the main influencing factor on intervertebral disc degeneration after lumbar fusion(OR=32.652,95%CI=1.684-632.948,P=0.021). Conclusion Preserving the supraspinal ligament of adjacent vertebral segment can obviously improve space angulation and Cobb′s angle. Besides,it is also the protective factor of adjacent segment degeneration after lumbar fusion.