椎间盘髓核摘除对腰椎间小关节承载功能影响的实验研究

目的分析椎间盘髓核摘除后腰椎小关节受力大小及变化情况。方法采用8具新鲜脊柱腰骶段(L1~S1)标本,在MTS系统上用压敏片分别测量L3-L4、L4-L5两个节段小关节面在中立位和前屈、后伸位时受力大小;摘除L4-L5椎间盘髓核,重复测量。结果完整脊柱标本中,L4-L5与L3-L4节段关节面受力大小相似:中立位时受力占轴向压缩载荷的15%;前屈10°、20°时受力占压缩载荷的比例减为9%、5%;后伸10°、20°时受力占压缩载荷的比例增至23%、33%。L4-L5椎间盘髓核摘除后,L4-L5节段小关节面在各个运动状态下受力均显著增大,而L3-L4节段小关节受力也有增加的趋势。结论腰椎小关节有一定的承载功能。腰椎间盘切除术后,同一平面及相邻平面小关节受力增加,可能引发腰痛。

Changes of force of the lumbar facet joints after lumbar disc excision: an in vitro study

Objective To study the force of lumbar facet joints before and after lumbar disc excision.Methods Totally 8 fresh lumbar-sacral spines(L_(1)-S_(1)) were placed on the MTS system.The compressive stress of the facet joints of the L_(3)-L_(4) and L_(4)-L_(5) motion segments was measured using pressure-sensitive films.The compressive stress on lumbar facet joints was measured in the position of erection,flexion and extension.Then L_(4)-L_(5) nucleus was resected and and the force was measured when the same positions were repeated.(Results) L_(3)-L_(4) and L_(4)-L_(5) segments could bear the same force before operation.In neutral position,the facet joints could carry about 15% axial compressive stress.In flexion posture,the force borne by the facet joints decreased.In flexion at 10,20,the force was about 9% and 5% of the compressive force.In extension position,the force of the facet joints increased.In extention at 10,20,the force was about 23% and 33%,respectively.After disc excision,the force of facet joints of L_(4)-L_(5) increased remarkably,and the force of L_(3)-L_(4) also had the trend of increase.Conclusion The lumbar facet joints can share some of the compressive forces of the spine.The force of facet joints of the disc-resected segment and the adjacent segment increases,which may be a reason of lumbar pain after disc excision.