下颈椎前路椎弓根螺钉内固定在三柱损伤模型中初始稳定性的生物力学研究

目的:比较下颈椎前路椎弓根螺钉内固定(ATPS)和3种传统颈椎内固定技术在下颈椎3柱损伤模型中的初始稳定性,为其临床应用提供力学依据。方法:采集6具人颈椎标本并测定各原始标本(原始标本组)的三维运动范围,制成三柱损伤模型,模拟钛网植骨后依次行ATPS、前路钢板固定(AP)、前路钢板+侧块螺钉固定(AP+LMS)、后路椎弓根螺钉内固定(PTPS),测量4种内固定技术下的三维运动范围,将结果标准化并进行相互比较。结果:ATPS组屈伸、侧弯、轴向旋转运动范围标准化数值分别为(77.17±4.75)%、(82.00±2.61)%、(83.17±2.23)%,均明显小于原始标本组的100%、100%、100%(P0.05)。AP组屈伸、侧弯、轴向旋转运动范围标准化数值分别为(119.67±7.42)%、(116.33±7.53)%、(112.67±5.99)%,均明显大于原始标本组(P0.05)。AP组屈伸、侧弯、轴向旋转运动范围标准化数值均明显大于ATPS组(P0.05)。PTPS组屈伸、侧弯运动范围标准化数值与ATPS组相比差异均无统计学意义(P0.05);其轴向旋转运动范围标准化数值为(86.83±2.48)%,明显大于ATPS组(P=0.009)。AP+LMS组屈伸运动范围标准化数值为(68.50±2.43)%,小于ATPS组(P=0.003);其侧弯、轴向旋转运动范围标准化数值与ATPS组相比差异均无统计学意义(P0.05)。结论:ATPS可在下颈椎三柱损伤模型中提供足够的初始稳定性,其在生物力学性能方面优于AP、PTPS,和AP+LMS相近,适用于无需后路切开减压复位的下颈椎三柱损伤病例。

Biomechanical study of the stability of subaxial cervical anterior transpedicular screw fixation for three-column injury

Objectives:To compare the stability of subaxial cervical anterior transpedicular screw(ATPS) fixation and three traditional fixations for three-column injury.Methods:Six specimens of cervical spine were prepared. After measurememt of the range of motion(ROM) in intact state,the specimens were made into three-column injury models. The models were reconstructed with an anterior cervical cage,and stabilized by ATPS,anterior plate(AP),anterior plate + lateral mass screw(AP+LMS) and posterior transpedicular screw(PTPS). The ROM of the models in the four states were measured,and the results of data were compared after standardization.Results:The normalized ROM of ATPS state in flexion-extension,lateral bending,axial rotation were(77.17±4.75)%,(82.00±2.61)%,(83.17±2.23)%,which were significant small than those in intact state(P<0.05). The normalized ROM of AP state in flexion-extension,lateral bending,axial rotation were(119.67±7.42)%,(116.33±7.53)%,(112.67±5.99)%,which were significant larger than those in intact state(P<0.05). The normalized ROM of AP in all directions were significant larger than those of ATPS(P<0.05). There was no significant difference between normalized ROM of PTPS state and those of ATPS state in flexion-extension and lateral bending(P>0.05). The normalized ROM of PTPS state in axial rotation was(6.83±2.48)% and was significant larger than that of ATPS state(P=0.009). The normalized ROM of AP+LMS state in flexion-extension was(68.50±2.43)%,which was significant smaller than that of ATPS state(P=0.003). There was no significant difference between the normalized ROM of AP+LMS state and those of ATPS state in lateral bending and axial rotation(P>0.05).Conclusion:Subaxial cervical three-column injury model reconstruction by ATPS can provide the adequate primary stability,of which biomechanics property is superior compared to AP and PTPS,and is similar to that of AP+LMS. It can be applied to the patients with no need to decompression and reduction through posterior approach.