下腰椎不同固定方式的生物力学对比研究

Biomechanics of different fixed patterns of low lumbar spine

目的观察下腰椎不同固定方式对腰椎稳定性的影响。方法新鲜成人尸体下腰椎标本6具，测定L4/5节段屈伸、左右侧屈、左右旋转6个方向ROM和刚度值的变化，按5组顺序依次测试：A组（正常下腰椎标本组）；B组（单侧椎板关节突螺钉固定＋椎间单枚Cage）；C组（单侧椎弓根螺钉固定＋椎间单枚Cage）；D组（单侧椎弓根螺钉联合对侧椎板关节突螺钉固定＋椎间单枚Cage）；E组（双侧椎弓根螺钉固定＋椎间单枚Cage）。结果与A组比较，B组各运动状态ROM有减少，而刚度明显增加，差异有统计学意义（P〈0．05）；与B组比较，C组各运动方向ROM与刚度，差异无统计学意义（P〉0．05）；与C组比较，D组各运动状态ROM有减少，而刚度增加，差异有统计学意义（P〈0．05）；与E组比较，D组各运动方向ROM与刚度，差异无统计学意义（P〉0．05）；与E组比较，C组各运动状态ROM有增加，而刚度减少，差异有统计学意义（P〈0．05）。结论单侧椎板关节突螺钉固定并椎间融合器植骨方法提供了一定的稳定性，而单侧椎弓根螺钉联合对侧椎板关节突螺钉固定并椎间融合器植骨具有与双侧椎弓根螺钉固定相同的稳定性，临床上可根据病例的具体情况，如身高体质量指数、病变类型及病变节段稳定程度选择性地应用上述两种固定融合方法。

Objective To observe the effects of different fixed patterns on low lumbar spine stability. Methods The spine specimens from 6 fresh adult cadavers were divided into five groups： group A （normal low lumbar vertebrae specimen） ; group B （unilateral translaminar facet screw fixation and interbody fusion） ; group C （unilateral pedicle screw and interbody fusion） ; group D （unilateral pediele screw combined with contralateral translaminar facet screw fixation and interbody fusion） ; group E （bilateral pediele screw and interbody fusion ）. A biomechanical test of compression in flexion, extension and lateral bending, as well as axial rotation, angular range of motion （Rom） and value of hardness was done. Results As compared with group A, ROM under every state of motion was decrease, and the stiffness was signifi- cantly increased in group B （ P 〈 0. 05 ）. There was no significant difference in ROM and stiffness between groups B and C （P 〉 0. 05 ）. As compared with group C, ROM was reduced and stiffness increased in group D （ P 〉0. 05 ）. There was no significant difference in ROM and stiffness between groups D and E （P 〈 0. 05）. As compared with group E, ROM was increased, and stiffness decreased significantly in group C （ P 〈 0. 05 ）. Conclusion Unilateral laminar facet screw fixation with bone graft fusion cage meth- od provides a certain stability, and unilateral pedicle screw combined with contralateral translaminar facet screw fixation and interbody fusion provides the same stability as bilateral pedicle screw fixation. The two fixed patterns can be applied on the specific situations of the cases, as for baric index, pathclogical features and the stability of segmengtal lesions.