横连对单节段短椎弓根螺钉内固定的影响

Effect of Cross-linkage on Monosegment Instrument with Short Pedicle Screw

目的测试使用横连在单节段短椎弓根钉内固定中的生物力学稳定性。方法使用10具小牛脊柱标本（T12~L3）模拟体外L1~2椎间盘周围型脊柱结核前路病变椎体切除手术,即切除L1~2间盘和邻近终板,行自体髂骨植骨,后路用单节段短椎弓根螺钉进行固定。测试该模型在不使用横连、使用1根横连、使用2根横连状态下在垂直压缩、侧弯、屈伸和扭转方向上的力学稳定性。结果在扭转载荷下,1根横连组和2根横连组分别与无横连组相比其相对运动范围（RROM）明显降低（P〈0.05） 而1根横连组和2根横连组相比差异无统计学意义（P〉0.05）。结论在扭转方向上横连能够明显增强结构的稳定性能 在单节段短椎弓根螺钉固定中,使用1根横连即能够达到最佳的抗扭转效果。

Objective To test the biomechanical stiffness of cross-linkage in monosegment instrument with short pedicle screw.Methods Ten fresh calf spines（T10～L5） were made into the mechanical test models of simulating spinal tuberculosis with being cut off the L1～2 intervertebral discs and the adjacent end plates,iliac grafting in situ and posterior monosegment fixation with short pedicle screw.stability of the models were Tested without cross-linkage,with 1 and 2 cross-linkages in axial compression,lateral bending,flexion-extension and rotation.Results The relative range of movement（RROM） of fixation with 1 cross-linkage and 2 cross-linkages was significantly lower than that of fixation without cross-linkage in rotation（P0.05）,however,comparison of RROM between 1 and 2 cross-linkages was no significantly different（P0.05）.Conclusion Cross-linkage provided increased torsional stiffness of posterior spinal construct.With 1 crosslinkage,the monosegment instrument with short pedicle screw will achieve the best effect to resist rotation.