前纵韧带损伤加重相应节段损伤椎间盘的退变

Degeneration of injured intervertebral disk affected by anterior longitudinal ligament destruction

背景:脊柱失稳可加速正常椎间盘的退变。在外伤导致脊柱失稳时,常同时存在前纵韧带合并椎间盘损伤。目前鲜有关于前纵韧带损伤对损伤后椎间盘退变影响的动物实验研究。目的:通过建立不同程度兔前纵韧带合并椎间盘损伤模型,观察脊柱失稳后损伤椎间盘的退变情况。方法:将24只新西兰大白兔随机分为4组,单纯椎间盘损伤组、椎间盘损伤+前纵韧带部分损伤组、椎间盘损伤+前纵韧带骨附着点断裂伤组和椎间盘损伤+前纵韧带中央横断组。经腹腔暴露L2至L3椎体,按分组分别对L2-L3椎间盘和局部前纵韧带进行相应处理。于术后4周和8周行CT检查,在矢状位二维重建图像上计算受损椎间隙中央高度,并进行统计学分析。摄片后每组随机选取3只兔子,处死后取损伤部位椎间盘组织行苏木精-伊红染色,光镜下镜检。结果与结论:(1)术后4周,椎间盘损伤+前纵韧带中央横断组受损椎间隙高度较单纯椎间盘损伤组明显降低(P<0.05),椎间盘损伤+前纵韧带骨附着点断裂伤组和前纵韧带中央横断组分别可见局部骨质增生和钙化;组织学观察发现椎间盘损伤+前纵韧带骨附着点断裂伤组和前纵韧带中央横断组髓核细胞减少,局部炎症反应较单纯椎间盘损伤组明显;(2)术后8周,椎间盘损伤+前纵韧带骨附着点断裂伤组和前纵韧带中央横断组受损椎间隙高度较单纯椎间盘损伤组明显降低(P<0.05),椎间盘损伤+前纵韧带骨附着点断裂伤组和前纵韧带中央横断组局部骨质增生和钙化较前明显;苏木精-伊红染色可见髓核细胞形态改变,髓核局部纤维化与纤维环分界模糊,退变程度椎间盘损伤+前纵韧带中央横断组>椎间盘损伤+前纵韧带骨附着点断裂伤组>椎间盘损伤+前纵韧带部分损伤组>单纯椎间盘损伤组;(3)结果表明,兔前纵韧带损伤可加重相应节段损伤椎间盘的退变,且椎间盘退变程度随前纵韧带损伤程度的增加而加重。

BACKGROUND： The spinal instability would accelerate the degeneration of normal disk. The injuries of anterior longitudinal ligament （ALL） and intervertebral disk were usually caused by cervical trauma, which leaded to spinal instability. Currently, there were few animal researches about the degeneration of injured intervertebral disk affected by ALL destruction.OBJECTIVE： To investigate the degeneration of injured intervertebral disk after spinal instability in the rabbit model of different degrees of ALL and disc destruction.METHODS： A total of 24 New-Zealand rabbits were randomly divided into intervertebral disk injury group （Group A, n=6）, partial injury of ALL with disc injury group （Group B, n=6）, injury of bony attachment point of ALL with disc injury group （Group C, n=6） and entirely injury of ALL with disc injury group （Group D, n=6）. The L2-L3 intervertebral disk and ALL were injured through abdominal cavity. Different groups received different treatments. Computed tomography （CT） scans of the injured disc were performed at the postoperative 4 and 8 weeks, and the middle high of injured discs was calculated on CT sagittal reconstruction. Three rabbits were selected from each group. Hematoxylin-eosin staining of injured disc was performed after the animals were killed. Results were examined under the light microscope.RESULTS AND CONCLUSION： （1） At postoperative 4 weeks, the middle height of injured discs in Group D was decreased significantly compared with Group A （P 〈 0.05）. There were hyperosteogeny and calcification in Group C and Group D. There were nucleus pulposus cells reduction and inflammatory reaction in Group C and Group D on histological staining. （2） At postoperative 8 weeks, the middle height of injured discs respective was decreased significantly compared with Group A （P 〈 0.05）. The hyperosteogeny and calcification became clearer in Group C and Group D than before. There were morphologic changes of nucleus pulposus cells and fibrillation by hematoxylin-eosin staining, and the degree of disc degeneration was Group D 〉 Group C 〉 Group B 〉 Group A. （3） In conclusion, the injury of ALL would accelerate the degeneration of correspondingly injured disk, and the degree of injury of ALL was positively correlated with the degeneration of disk.