下颈椎经关节螺钉钢板固定的生物力学研究

目的:研究下颈椎单独经关节螺钉固定与经关节螺钉钢板固定的三维稳定性之间的差异。方法:12具新鲜人体颈椎标本,制成C4,5、C5,6节段三柱损伤模型。随机选取6具标本在C4,5、C5,6行单独经关节螺钉固定,另6具标本在C4,5、C5,6行经关节螺钉钢板固定。在非限制性和非破坏性的试验条件下测试它们在前屈、后伸、左右侧弯和轴向旋转运动状态的稳定性,分别测试标本损伤模型制作前完整标本组(A组)、单独经关节螺钉固定组(B组)和螺钉钢板组(C组)3组数据。结果:单独经关节螺钉固定组和经关节螺钉钢板固定组在各方向的运动范围(ROM)和中性区(NZ)的均数均小于完整标本组,差异有统计学意义(P0.05)。经关节螺钉钢板固定在前屈运动中的ROM和NZ与单独经关节螺钉固定比较,差异无统计学意义(P0.05);在后伸、左右侧弯和轴向旋转运动中,经关节螺钉钢板固定的稳定性优于单独经关节螺钉固定,差异有统计学意义(P0.05)。结论:下颈椎经关节螺钉钢板固定的稳定性优于单独经关节螺钉固定,在使用下颈椎经关节螺钉时,相对于单独螺钉固定,建议以螺钉钢板形式固定。

Biomechanical study on transarticular screw and plate fixation syetem in the lower cervical spine

Objective: To compare the cervical stabilities of transarticular screw fixation alone,and transarticular screw and plate fixation system. Methods: Twelve specimens of cervical vertebra containing C₂-T₁ were obtained from human cadaver. The three-column instability model was made at C_4,5 and C_5,6 levels. The specimens were stabilized with transarticular screw fixation alone,and transarticular screw and plate fixation system respectively. The ranges of motion of segments including intact group,transarticular screw fixation alone group and transarticular screw and plate fixation system group were measured under the torque of 2.0 N·m in flexion,extension,lateral bending,and torsion respectively under nonrestrictive and nondestructive condition. Results: The rang of motion(ROM)and neutral zone(NZ) of both transarticular screw fixation alone and transarticular screw and plate fixation system group were significantly smaller than those of intact group in all directions(P<0.05). The transarticular screw and plate fixation system 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: Cervical transarticular screw and plate fixation system provides better stability than transarticular screw fixation alone. If the transarticular fixation technique is preferred,transarticular screw and plate fixation system will be beneficial.