两种腰椎椎弓根螺钉固定技术的生物力学对比研究

Biomechanical comparison of two methods of lumbar pedicle screw placement

目的:比较两种腰椎椎弓根螺钉置钉技术的生物力学差异。方法:12具经防腐固定的L1～5节段成年脊柱标本,分为人字嵴顶点法、Magerl法两个螺钉固定组。采用858型MTS材料实验机进行轴向拔出力测试,记录最大拔出力,并对两组进行比较;试验完成后,将标本沿椎弓根截面锯开,观测两种方法的进钉外倾角度.结果:人字嵴顶点法进钉外倾角度小于Magerl法(P<0.05);人字嵴顶点法和Magerl法的最大钉拔出力无明显差异(P<0.05)。结论:采用人字嵴顶点进钉法操作方便且显露范围小,而且能够获得相同的生物力学稳定,值得临床推广应用。

Objective： TO biomechanically compare in two different techniques （Magerl and ＂∧＂-shaped crest） of lumbar pedicle screw placement. Methods： 12 adult human embalmed cadavers （L1-5） were used. Specimens were divided into two groups according to the difference of entrance points for lumbar pedicle screw insertion. The testing of the withdrawal force was performed using MTS858 Mini Bionix material testing machine, and the maximum of withdrawal force were recorded and analyzed. The angle ofpedicle screws were measured respectively. Results： For the angle of screw placement, the group using ＂∧＂-shaped crest as drilling points was significantly smaller than the group using Magerl techniques （P〈0.05）. However, no significant difference of the maximum of withdrawal force was detected between two groups （P〉0.05）. Conclusions： Using ＂ ∧＂-shaped crest as entrance point of pedicle screw has the advantage of easily placement and smaller exposure, and receives the identical biomechanical stability.