下颈椎经关节螺钉钉棒系统固定的生物力学研究

Biomechanical study of transarticular screw-rod system fixation in the lower cervical spine

目的:比较下颈椎三柱损伤后单独经关节螺钉固定(TAS)、经关节钉棒系统固定(TRS)和侧块螺钉钉棒系统固定(LRS)的三维稳定性。方法:12具新鲜颈椎标本,制成C4/5、C5/6节段三柱损伤模型,分别进行单独经关节螺钉(TAS组)、经关节螺钉钉棒系统(TRS组)和侧块螺钉钉棒系统(LRS组)三种方法固定,在非限制性和非破坏性的实验条件下测试其前屈、后伸、左右侧弯和轴向旋转运动状态的稳定性。结果:TAS组和TRS组在各方向的运动范围(ROM)和中性区(NZ)的均数均显著小于完整标本组,差异有统计学意义(P<0.05);LRS组在前屈、后伸、侧弯运动中的ROM和NZ与完整标本组比较有显著降低,差异有统计学意义(P<0.05);LRS组在旋转运动中的ROM和NZ与完整标本组比较有不同程度的降低,但差异无统计学意义(P>0.05)。TAS、TRS在各个方向稳定性明显优于LRS组(P<0.05)。TRS在前屈运动中的ROM和NZ与TAS组比较有所减小,但无统计学意义(P>0.05);在后伸、侧弯和旋转运动中,TRS组稳定性明显优于TAS组,有统计学意义(P>0.05)。结论:在下颈椎三柱损伤选择经关节固定技术时以钉棒形式固定稳定性更好。

Objective：To compare the lower cervical stabilities of transarticular screw fixation alone,screw/rod system fixation and lateral mass screw/rod system fixation.Method：12 specimens of cervical vertebra containing C2-T1 were obtained from human cadaver.The three-column instability model was made at C4/5 and C5/6 level.The specimens were stabilized with transarticular screw fixation alone（group TAS）,screw/rod system fixation（group TRS） and lateral mass screw/rod system fixation（group LRS） respectlvely.The ranges of motion of instrumented segments were also measured under the torque of 2N·m in flexion,extension,lateral bending, and rotation respectively under nonrestrictive and nondestructive condition.The data between groups were compared with statistical analysis.Result：The range of motion（ROM） and neutral zone（NZ） of both transarticular screw fixation alone and screw/rod system fixation group were significantly smaller than those of intact group in all directions （P〈0.05）.The ROM and NZ of lateral mass screw fixation group were significantly smaller than those of intact group during extenslon,lateral bending and flexion except axial rotation （P〈0,05）.The ROM and NZ of both transarticular screw fixation alone and screw/rod system fixation group were significantly smaller than those of lateral mass screw fixation group in all directions （P〈0.05）,The transarticular screw/rod system fixation group allowed a very smaller ROM and NZ than transarticular screw fixation alone during extension,lateral bending and axial rotation except flexion （P〈0.05）.Conclusion：As for three column injury in lower cervical spine,transarticular screw/rod system is preferred to better stability.