脊柱交界区终板抗压强度分布规律的生物力学研究

Stress distribution of endplate at cervicothoracic,thoracolumbar and lumbosacral junction:a biomechanical study

目的:探讨脊柱交界区终板不同位点抗压强度及其分布规律。方法:选用5具成年男性新鲜脊柱标本的颈胸段、胸腰段及腰骶段,共65个椎体125个终板,采用环形取点的方式,对每个终板平面的49个测试点用直径1.5mm的平底压头进行连续压缩加载试验,获得最大压缩力,所得数据进行统计分析。结果:以椎体为单位,颈胸段终板从C4开始抗压强度逐渐下降,至C7达到最低点,C7～T1明显升高。胸腰段各椎体终板的抗压强度呈依次上升趋势,腰骶段L3、L4终板抗压强度继续上升,L5出现降低,S1节段再次升高。颈胸段与胸腰段抗压强度均小于腰骶段(P<0.01)。上下终板抗压强度变化趋势相似。各段椎体抗压强度下终板强于上终板(P<0.01)。椎间隙相邻面上一椎体下终板的抗压强度大于下一椎体上终板(P<0.05)。由内至外,抗压强度逐渐增大(P<0.05)。颈胸段和腰骶段的后部终板抗压强度大于前部,而胸腰段为前部大于后部(P<0.05)。结论:不同节段终板的抗压强度分布规律不同,临床安放椎间置入物时需注意置入物的大小及放置位置。

Objective：To investigate the stress distribution of endplate at cervicothoracic,thoracolumbar and lumbosacral junction.Method：A total of 65 vertebral bodies（125 endplates） from 5 intact human vertebrae（C4-T1,T11-L2,L3-S1） was used for test,49 test points at each endplate were indented by using a 1.5mm-diameter plane indenter,a continuous load was added in all specimenand,the results were processed by statistical analyses.Result：The failure load distributions of endplates varied significantly among the three sites.At cervicothoracic junction,the failure load decreased from C4 to C7,and increased from T1.At thoracolumbar junction,the failure load increased from T11 to L2,which continued to L3 and L4,but ceased in L5,and then increased again from S1.The yield load in endplates of cervicothoracic and thoracolumbar junction was lower than that in lumbosacral junction（P0.05）.The failure load of inferior endplates was significantly higher than that of superior endplates（P0.01）.As for intervertebral space,the cranial endplates had a higher yield stress than caudal endplates（P0.05）.The failure load increased from central to peripheral zones.At cervicothoracic and lumbosacral junction,the failure load of posterior endplates was higher than anterior regions,but on the contrary for endplates of thoracolumbar junction（P0.05）.Conclusion：The stress distributions of the endplates vary significantly among three junctions.It is cautious to consider their size and location when placing instrument.