猪腰椎间盘髓核摘除术后疲劳载荷对椎间盘形态的影响

The effect of fatigue load on the lumbar disc morphology after disectomy:a pig model

目的探讨腰椎间盘髓核摘除术后疲劳载荷对椎间盘形态的影响。方法取4具年轻猪新鲜脊柱标本,随机分为手术组(A组)和非手术组(B组),各制成8个脊柱功能单位(FSU),A组行单侧椎板开窗髓核摘除术。两组在相同的设置参数下(前屈9°,旋转3°,轴向载荷最大载荷取3500N,载荷频率为3Hz)行疲劳加载实验,加载前后均行椎间盘造影,分别测量椎间盘总面积、纤维环区面积、髓核区面积及髓核区造影剂所占面积。实验后均行椎间盘美兰染色观察横截面形态。结果A、B两组疲劳载荷后椎间盘总面积均增大(P<0.05);A组疲劳载荷后纤维环区面积增大(P<0.05),髓核区面积无明显变化(P>0.05);B组疲劳载荷后纤维环区面积缩小(P<0.05),髓核区面积增大(P<0.05);A、B两组疲劳载荷后造影剂所占髓核区面积均增大(P<0.05),B组加载后造影剂所占面积与A组相比较增大(P<0.05);美兰染色显示A、B两组疲劳载荷后均未见有明显的纤维环裂隙,与椎间盘造影图像基本相符。结论本实验对解释临床上年轻患者术后疗效普遍好于中、老年患者,提供了一定的动物实验生物力学基础。

Objective To investigate The effect of fatigue load on the pig lumbar disc appearance after disectomy. Methods d samples of pig lumbar spines were selected and divided into two groups randomly：operative group during unilateral vertebral plate disectomy （group A） and control group （group B）. Each group was dissected into 8 functional spinal units （FSU） and subjected to fatigue loading under the same parameter （the flexion angle was 9°,the rotation angle was 3°,the peak load was 3500N,the load frequency was 3Hz）. Discography was taken on every sample before and after fatigue load experiment to measure the dimension of total disc,annuli fibrosi area,nucleus area and contrast agent area respectively. Frozen sections were taken on two groups after fatigue load experiment. Results Total disc dimension of two groups increased after load experiment（P〈0.05）. Group A showed that annuli fibrosi area increased（P〈0.05） and nucleus area did not change after load experiment （P〉0.05）.Group B showed that annuli fibrosi area decreased（P〈0.05） and nucleus area increased after load experiment（P〈0.05）. Contrast agent area in nucleus area of two groups increased after load experiment （P〈0.05） and the proportion of Contrast agent area to nucleus area of group B was greater than that of group A after load experiment （P〈 0.05）. No annuli fibrosi tear was found in two groups either by discography or by frozen section. Conclusion This experiment provid the biomechanical foundation of animal experiments for explaining the clinical effects on young patients generally better than on elderly patients.