单节段腰椎活动度对邻近节段运动的影响

背景：有研究报道腰椎融合后其邻近节段运动范围和压力会明显增大;但也有报道腰椎融合与动态固定非融合或正常腰椎相比,其邻近节段运动范围和压力未见明显增加,甚至出现减少。然而,腰椎的活动度多少到底对邻近节段会有什么影响呢？目的：观察单节段腰椎不同范围活动度对邻近关节运动范围的影响。方法：取6具新鲜成人L2～S2腰椎标本,依次对成人L4～L5椎体进行不同方式处理形成5种不同活动度状态：完整标本状态;部分失稳状态;动态固定状态;完全失稳状态;刚性固定状态。在脊柱三维运动试验机上,采用＂载荷控制＂法进行屈伸、侧弯和旋转等运动方向测试,分别将其他4个状态与完整标本状态进行比较。结果与结论：处理节段L4～L5椎体在各处理状态的下运动范围明显不同,形成了完全不同范围的活动度。与完整标本状态相比较,其他4个状态旋转时,上方邻近节段L3～L4的运动范围在刚性固定状态下明显减少;下方邻近节段L5～S1各方向和上方邻近节段L3～L4其余方向的运动范围无显著性差异。单节段腰椎刚性固定状态下,整个脊柱标本的运动范围明显减少。说明在＂载荷控制＂方法的实验下,单节段腰椎活动度多少对邻近节段的屈伸、侧弯等运动范围影响不明显,对上方邻近节段的旋转运动范围影响较大;腰椎刚性固定融合后,不一定要恢复到正常腰椎的活动范围,也许对预防邻近节段病有利。

Influence of lumbar mono-segmental activity on motion of the adjacent segments

BACKGROUND：Studies have reported that range of motion（ROM） and pressure of adjacent segments increased after lumbar fusion;but some studies showed,compared with dynamic non-fusion systems or normal lumbar segment,the ROM and pressure of adjacent segment are decreased rather than increased.However,the precise affects of lumbar mono-segmental activity on adjacent segments are unclear.OBJECTIVE：To explore the influence of single-segmental lumbar ROM on the motion of adjacent segments.METHODS：Six fresh-frozen adult lumbar spines（L2-S2） were used.In a same specimen,these four kinds of operation by gradually at L4-L5 level represent different degrees of mobility.So five conditions were built as following：condition A：intact specimen;condition B：part of the instability;condition C：elastic fixed non-fusion（COFLEX）;condition D：complete instability;and condition E：rigid fixation and fusion.Spinal three-dimensional motion testing machine were used.Each group specimen ROM in flexion-extension and bilateral lateral bending and bilateral axial rotation were determined.All values were normalized to the value of intact specimen group.RESULTS AND CONCLUSION：About range of motion,in the processing segments（L4-L5）,there were the greatest range of motion in condition D and the least range of motion in condition E.The influence of monosegmental lumbar mobility on adjacent segment range of motion is no significance but axial rotation after rigid fixation and fusion that was reduced of cranial adjacent segment（L2-L3）.Global specimen in each group ROM significantly different,their changing patterns was consistent with L4-L5 level mobility.In the load control,the influence of single-segmental lumbar stability on adjacent segment range of motion was not obvious.Patient with lumbar fusion using the normal force may be beneficial to prevent spine from adjacent segment disease.