三种椎间融合器对腰椎节段即时稳定性影响的三维运动研究

Biomechanical evaluation of lumbar spine segmental stability after insertion of 3different interbody fusion cages

目的比较3种不同类型的后路腰椎椎间融合器的生物力学稳定性。方法采用8具人尸体新鲜腰椎3、4节段标本,模拟后路双侧植入3种椎间融合器。实验分4组7个状态:①对照组(完整标本,In-tact),②螺纹状融合器组(Interfix),③空心箱形融合器组(SynCage),④实心箱形融合器组(Prospace),后3组再分别固定椎弓螺钉钢板。随机安排每个标本的融合器植入顺序。在脊柱三维运动试验机上测试不同状态的三维六个方向上的运动范围。结果各融合器的前屈运动范围与完整状态相比具有统计学差异(P<0.01);不同融合器之间则无明显差异(P=0.17)。在后伸运动上,各融合器组较完整状态组以及各融合器之间均无明显差异(P=0.25)。侧屈方向,各组融合器的植入均明显提高了稳定性(P<0.01),不同融合器之间未表现有明显差异(P=0.15)。不同融合器组在旋转运动时的ROM均较完整状态明显增加(P<0.01),同时Interfix组与其它2组融合器之间也有统计学差别(P<0.01),Prospace和SynCage之间则无明显差异(P=0.58)。后路固定椎弓螺钉钢板后,腰椎各向ROM值均较单纯的融合器固定组显著降低(P<0.01)。结论3种融合器之间在除外旋转运动的所有方向的稳定性无统计学差异。单独运用3种椎间融合器均无法在所有方向上达到与完整节段一致的生物力学稳定性。

Objective To evaluate the biomechanical stabi lity of 3different lumbar interbody fusion cages.Methods 8human cadaver lumbar spine specime ns(L3/4)were designed to compare 3different cages.They were divided into 4groups:(1)control(intact);(2)threaded cage;(3)hollow rectangle cage;(4)solid rectangle cage.Different cages were inserted randomly.The 3cage groups were fixed again with posterior transpedicular screw plate system.All the groups were tested fo r range of motion using a spinal 3-dim ensional analysis system.Results No statistical differences were observed in construction stability among the cages in most of the testing modalities except that of the axial rotation.The cages used alone significantly decreased the intervertebral movement in flexion and lateral bending,but no stabilization was gained in either extension or a xial rotation.For all types of the cages,the manifest stabilization in all direc tions was achieved by addition of posterior transpedicular instrumenta tion.Con-clusion All types of the cages tested cannot provide sufficient stabilization eq uivalent to the intact FSU in vitro,but the combined application of cages an d posterior transpedicular instrum entation can significantly increase lumbar spine segmental stability.[