腰椎K-rod弹性内固定系统与刚性内固定系统体外应力遮挡效应的对比分析

【摘要】 目的:对比分析腰椎k-rod弹性内固定系统与刚性内固定系统体外应力遮挡效应,为临床提供生物力学基础。方法:选取12具12月龄雄性猪脊柱胸12-腰5标本随机分为k-rod弹性内固定组6个标本,刚性内固定组6个标本,对两组标本进行应变电测量,对椎弓根螺钉内固定前标本在腰4、5椎体固定螺钉孔边缘外下方、腰4、5椎体两侧横突前方及腰4、5椎体前方正中作为测点,选择10个测点粘贴电阻应变片,在电子万能试验机上模拟人的生理功能在前屈状态下施加150Nf载荷,通过静态电阻应变仪测试各组标本固定前的应变值。然后对各组标本腰椎后路(L4-5)分别以k-rod弹性内固定器及刚性内固定器进行固定,1-10号测点与行椎弓根螺钉内固定前各组标本测点位置相同,为了测量内固定连接棒与椎弓根螺钉交界处的应变,在内固定棒与椎弓根螺钉交界处增加四个测点(11-14号测点),对以上测点粘贴电阻应变片,在电子万能试验机上模拟人的生理功能在前屈状态下施加150Nf载荷,通过静态电阻应变仪测试标本固定后的应变值。结果:内固定后,在前屈载荷作用下1、2、5、6、9、10测点k-rod弹性内固定组标本的应力值小于刚性内固定组标本的应力值,差异显著(P<0.05);3、4、7、8测点k-rod弹性内固定组标本的应力值大于刚性内固定组标本各测点的应力值,差异显著(P<0.05)。k-rod弹性内固定系统所产生的应力遮挡效应小于刚性内固定系统。结论:腰椎k-rod弹性内固定系统的设计符合生物力学原理。更多还原

【Abstract】 Objective:A vitro comparative analysis of stress shielding effect within the lumbar K-rod dynamic fixation and rigid fixation to provide a basis for clinical biomechanics.Methods:12spine with T12 to L5of 12-month-old male pig were randomly divided into K-rod dynamic fixation group and rigid fixation group with six specimens in both,conduct Strain measurement in both groups,pedicle screw fixation specimens below the waist before fixing screw holes L4-5vertebral outer edge,on both sides of the transverse processes of L4-5vertebra in front of the middle as the measuring point,select 10 Paste resistance strain gauge measuring point,Sims on the electronic universal testing machine 150 Nf load applied physiological functions in flexion by static resistance strain gauges fixed before the test strain samples in each group.Then each group specimens posterior lumbar(L4-5)respectively in the k-rod holder elasticity and rigidity within retainers,No.1-10 measuring point with pedicle screw fixation point before measuring samples in each group the same location,in order to measure strain within a fixed connection rod and pedicle screws at the junction of the inner rod and pedicle screw fixation at the junction of four additional measuring point(measuring point No.11-14),the measuring point above resistance paste strain gauges,analog people in the electronic universal testing machine 150 Nf load applied physiological functions in flexion by static resistance strain gauge strain test specimen after fixation.Results:After fixation,stress values of measurement points 1,2,5,6,9,10 in K-rod dynamic fixation is less than that in rigid fixation under front-flexion load,the difference was significant(P <0.05);stress values of measurement points 3,4,7,8in K-rod dynamic fixation is larger than that in rigid fixation.the difference was significant(P <0.05);.stress shielding effect of K-rod dynamic fixation is less than rigid fixation.Conclusion:K-rod dynamic fixation is more biomechanically.更多还原