基于有限元分析的钛合金椎弓根螺钉插入不同骨质性能研究

Performance study of titanium alloy pedicle screw insertion into different bones based on finite element analysis study on the performance of titanium alloy pedicle screw inserting different bones based on finite element analysis

钛合金因其优异的力学性能和生物相容性,广泛用于椎弓根螺钉的制备。椎弓根螺钉插入椎骨时,松质骨密度和皮质骨厚度都会对椎弓根螺钉插入稳定性产生影响,因此,有必要研究它们对椎弓根螺钉插入性能的影响。先通过有限元仿真方法研究不同骨质对椎弓根螺钉插入阶段的插入扭矩与骨应力的影响;再选用不同密度的聚氨酯泡沫作为骨材料,对标准钛合金椎弓根螺钉的插入过程进行力学性能测试。结果表明:相较于松质骨密度,皮质骨的厚度对螺钉插入稳定性的影响更大;皮质骨厚度的减小和松质骨密度的降低都会削弱椎弓根螺钉在插入时的插入扭矩;仿真结果与力学实验结果具有较高的一致性,表明有限元仿真方法可以用于椎弓根螺钉的插入扭矩预测。

Titanium alloys are widely used to make pedicle screws because of their excellent mechanical properties and biocompatibility.When the pedicle screws are implanted into the vertebrae,both trabecular bone density and cortical bone thickness affect the implant stability of pedicle screws.Therefore,it is necessary to study their effects on the implant performance of pedicle screws.Firstly,the influence of different bones on the insertion torque and bone stress during the implantation stage of pedicle screws was studied by finite element simulation method.Then polyurethane foams with different densities were selected as bone materials to test the mechanical properties of standard titanium alloy pedicle screws during implantation.The results indicate that compared with trabecular bone density,cortical bone thickness has a greater impact on the stability of screw implantation.The reduction of cortical bone thickness and the decrease of trabecular bone density both weaken the insertion torque of pedicle screws during implantation.The simulation results are highly consistent with the mechanical experiments,suggesting that the finite element simulation method can be used for predicting the insertion torque of pedicle screws.