长节段单椎体压缩性骨折动物模型的建立

The establishment of animal model of compression fracture of multisegmental and single vertabral body

目的:介绍一种用于评价脊柱不同内固定对脊柱稳定性影响的离体动物长节段单椎体不稳定性压缩骨折模型。方法:收集12例6￣8周新鲜小牛T12￣L3节段胸腰椎标本,采用G epstein改良方法对标本的中间椎体L1进行预损伤,前屈10°并轴向加载,预加载1 000 N,然后以0.1 s的时间迅速下压L1椎体椎前高度的1/2距离,使L1椎体骨折,之后以5 m m/m in的速度将L1椎体压至椎前高度减少1/2,椎体中部骨折线形成;分别测试正常标本、模型标本的椎前高度、前屈-压缩刚度和T13￣L2节段的中性区(N Z)和三维运动范围(RO M)。结果:L1压缩性骨折模型制作理想,模型标本L1的椎前高度平均约占完整标本的51.26%,椎管前壁完整、脊柱后柱未见明显损伤;模型标本前屈-压缩刚度较完整标本显著减少(P<0.0001);T13￣L2节段在前屈、后伸、左/右侧弯、左/右旋转方向的中性区(N Z)、运动范围(RO M)均较完整标本明显增大(P<0.001或P<0.0001)。结论:此种离体、长节段、单椎体不稳定性动物压缩性骨折模型较为理想,可用于评价不同脊柱内固定对脊柱稳定性的影响。

Objective： To introduce a kind of animal model of compression fracture of multisegmental and single vertabral body for evaluating spinal stabilization under different kinds of internal fixation, Methods： 12 flesh T12-L3 spine specimens of calves, aged from 6 to 8 week were collected. The body of L1 vertebrae were injuried by improved Gepstein method, after that, specimans were installed on the MTS test machine for loading, with the anterior flexion of 10o and the force of 1000N. The fracture of L1 body was performed by rapid impacting on the anterior 1/2 of the body during 0.1s, with the speed of 5mm/min. The height of L1 anterior body, the stiffness of flexion-compression and the range of three dimentional motion of T13-L2 were measured in normal and injured specimens. Results： An ideal model of compression fracture was finished. The anterior height of L1 body of the model was about 51.26% comparing with normal ones. Intact anterior wall of vertebral canal and posterior column could be observed. The stiffness of flexion-compression of model decreased significantly （P〈0.0001） and the motions of T13-L2 segments on flexion/extention, left/right bending and left/right rotation increased significantly （P〈0.001 or P〈 0.0001） after the injury. Conclusions： The fracture model established provides an ideal tool for biomechanical evaluation of the internal fixation devices of spine.