腰椎峡部裂翼状记忆合金节段内固定器的研制

目的研制治疗腰椎峡部裂的新型记忆合金节段内固定器,测试其材料力学特性,并进行有限元分析和生物力学稳定性评价。方法依据干燥完整的成人腰椎标本相关解剖数据的测量结果,利用镍钛记忆合金良好的形状记忆功能和独特的生物力学特征设计一种整体型翼状腰椎峡部裂记忆合金节段内固定器,并进行材料力学测试和有限元分析。应用脊柱三维运动实验机进行生物力学测试。结果材料力学测试及有限元分析表明其形态记忆功能良好,体温状态下能产生稳定可靠的回复力,且应力分布均匀,抗拉能力强,具有弹性固定作用。峡部裂腰椎6种运动状态时的生物力学稳定性均明显下降,而应用翼状记忆合金节段内固定器可明显恢复其稳定性。结论新型翼状记忆合金节段内固定器符合腰椎解剖结构特征,设计合理,抗拉能力强,应力分布均匀,能使腰椎峡部裂达到具有弹性的坚强节段内固定。

Experimental study on a new type of shape memory alloy intrasegmental fixation instrument for the treatment of lumbar spondylolysis

Objective To design a new type of shape memory alloy intrasegmental fixation instrument for the treatment of lumbar spondylolysis, researching its material mechanical characteristic,analyzing the finite element method(FEM) and evaluating the ability of the new device to restore the spine stability. MethodsBy the datas from measuring 20 cases of dried adult lumbar spine specimens, to design a integer-type of aliform-shape memory alloy intrasegmental fixation instrument, according to the favourable shape-memory ability and the distinct biomechanics-characteristics of nickel-titanium shape memory alloy, then to research its material mechanical property and finite element method analysis. To research biomechanics applying to the spinal column three-dimensional(3D) motion experiment machine. ResultsThe research of material mechanics property of new device and finite element method analysis showed that its function of shape memory was very good. It could produce credible and stable restore strength under the body temperature. There were the function of elastic fixation and the properties of the well-distributed tensile stress and the powerful tensile strength. Under the state of six motions, the stabilities of lumbar spondylolysis group obviously descended, but those could be resumed distinctly in the group by using the aliform-shape memory alloy intrasegmental fixation instrument. ConclusionNew designed aliform-shape memory alloy intrasegmental fixation instrument accords with the anatomic structure of lumbar spine, which is designed reasonably. There are the properties of the well-distributed tensile stress and the powerful tensile strength, so that it makes lumbar spondylolysis being of elastic and forceful intrasegmental fixation.