【作者】 杨明；

【导师】 卢畅；

【作者基本信息】 中南大学 ， 脊柱外科， 2009， 硕士

【摘要】 目的:通过测量纳米羟基磷灰石/聚乳酸材料的力学强度,及分析纳米羟基磷灰石/聚乳酸复合椎间融合器的生物力学性能,为该复合材料的进一步研究开发提供参考资料。方法:研究由三个部分组成:(一)将纳米羟基磷灰石于粘均分子量50万单位的聚乳酸采用超声振荡共混,真空干燥后在170℃,110MPa热压成型制备成不同纳米羟基磷灰石质量百分比(0、5%、10%、15%、20%、25%)的纳米羟基磷灰石/聚乳酸复合材料,并对其力学性能(抗弯强度、压缩强度和弯曲模量)进行测试,选力学性能最佳者进行下一步实验。(二)以8具青年男性新鲜腰椎(L1～L5)尸体标本进行试验,将实验结果分为三组:对照组、自体髂骨组、纳米羟基磷灰石/聚乳酸复合椎间融合器组。分别测量完整腰椎标本、自体髂骨植入和纳米羟基磷灰石/聚乳酸复合椎间融合器植入后腰椎在轴向压缩、前屈、后伸、左右侧弯工况下载荷-位移情况,采用实验应力分析方法,测量不同情况下腰椎轴向刚度,并对结果进行统计学处理,比较不同情况下的即刻稳定性。(三)取新鲜成年人体腰椎及髂骨标本12具,随机分为3组,分别是:对照组、自体髂骨组、复合椎间融合器组。将待测实验组标本安放于电子万能材料试验机上进行极限载荷-位移测试,记录载荷--位移曲线,椎体出现塌陷或压缩性骨折的标准是载荷--位移曲线出现最高点,即椎体的载荷出现下降。试验机的载荷信号由计算机数据采集系统记录,并由相应的测试分析分别测量其最大载荷及位移。结果:随着纳米羟基磷灰石的质量比增加其复合材料的压缩强度逐渐增大,弯曲强度开始随着纳米羟基磷灰石质量比的增加而增大,在羟基磷灰石微粒的质量比为15%时弯曲强度出现峰值(159.6MPa)。与对照组比较,自体髂骨组在后伸以及左右侧弯时的轴向刚度分别降低13.8%、15.3%、14.0%,可吸收椎间融合器组在后伸以及左右侧弯时的轴向刚度分别降低了12.6%、14.3%、16.4%,但后两者之间并无统计学差异(P＞0.05)。髂骨组的承载能力最差,仅为对照组标本的60.4%;复合椎间融合器组承载能力明显好于自体髂骨组。结论:综合考虑认为15%纳米羟基磷灰石含量的复合材料的力学强度最佳,能满足脊柱重建中作为替代骨的生物力学要求。纳米羟基磷灰石/聚乳酸复合椎间融合器能满足腰椎前路重建中生物力学稳定性的要求。而且具有良好的轴向压缩载荷和椎间支撑能力,力学性能优异,是一种比较理想的椎体替代材料,具有极好的应用前景更多还原

【Abstract】 Objective:To determinate the biomechanical performance of nano-hydroxyapatite ( n-HA) /polylactic acid ( PLA) compound material and evaluate the biomechanical capability of the interbody fusion cage of n-HA/PLA , to provided referenced data for the advance study of this bioactive material.Materials and Methods: This study was divided into two parts. Part one:The HA and PLA(MW=500000)solution were mixed by ultrasound then the mixture was dried.The mixture was further heating-molded in 170℃and under the pressure of 110Mpa to produce the composite specimens. Co-mixture of the compound craft preparation was applied to prepare n-HA/PLA compound material of different n-HA mass fraction (0、5%、10%、15%、20%、25%). Its mechanics performance(pressure strength、bending strength、curving module) were tested. Part two: To evaluate the immediate stability, 8 fresh lumber spine specimens(L1～L5) from young male cadavers were used ,Thespecimens were classified into 3 groups:the control group , auto iliac bone group and n-HA/PLA interbody fusion cage group. Load-displacement tests were performed in pure compression,flexion, extension, and lateral bending on each group, The axial stiffness of various group were analysed by stress analysis method, The results were statistically analyzed. Part three: The lumber vertebrae L1～L5 were obtained from twelve fresh adult male corpse and were randomly divided into three groups which were control group, iliac bone group, the bioactive interbody fusion cage group. To-be-tested experimental groups were set on the electronic universal material testing machine to test the load displacement,taking down the curve of the load displacement. When the vertebrae began to dent or fracture compressed,the load displacement curve came to the highest point,and the load of the vertebrae began to drop.Information of the load was taken by computer data collection system,testing the highest load and displacement respectively by analyzing the test accordingly.Results: With the percentage of n-HA inereasing, the pressure strength of the composites increas .The bending strength of compound material increased at first and then decreased.When the mass fraction of HA was 15%, the bending strength appeared the peak value (159.6 MPa). During extension、left and right bending, Comparing with the intact group,the mean axis compression stiffness of auto iliac bone group was decreased by 13.8%、15.3%、14.0% , and n-HA/PLA interbody fusion cage group was decreased byl2.6%、14.3%、16.4% respectively.but no significant difference was detected between the two devices ( P>0.05). The ultimate load and displacement of the iliac bone group is the lowest,only 60.4% of the control group.The bioactive interbody fusion cage group group has very good load capacity better than iliac bone group.Conclusions: 15 percent of n-HA in the compound material is considered as the best pereentage.It can meet the biomechanics performance requirement of spinal reconstruction. The n-HA/PLA interbody fusion cage could meet the demands of lumbar biomechanical stability and has good biological activity,load capacity of axial compress as well as vertebrae supporting capacity with excellent biomechanic performance,which can be an excellent material for vertebral replacement with promising prospect for application.更多还原