人工听骨传声特性的有限元分析

目的:探讨局部置换听小骨的假体材料对手术后传导性耳聋患者能重新获得听力效果的影响。方法:将人体正常耳CT扫描结果,用自编软件将CT扫描数值化并导入PATRAN重建三维有限元模型,应用动力学的传导振动原理,对正常的听小骨结构进行动力数值计算分析,并与现已报道的试验结果对比。对置换的听小骨假体分别赋值不同的的材料参数进行动力计算分析,与正常的听小骨结构力学行为进行对比。结果:中耳三维有限元模型计算所得频率响应曲线与由新鲜颞骨测试所得频率响应曲线的大小及分布基本一致。随着弹性模量的不断增大,镫骨足板振幅也变大,且越来越接近正常人体的镫骨足板振幅,当弹性模量大于115000gpa,镫骨足板振幅曲线变化率较小,几乎呈一条水平线。结论:本研究模型正确可信;手术置换材料物理参数的选择应突破以往临床中主要考虑材料密度的倾向,而应该重点考虑弹性模量,所取材料的弹性模量越大,置换后的患者听力恢复效果越好,当弹性模量达到115000gpa为极值,听力的恢复效果不再增加。

Finite Element Modeling of Ossicle for Sound Transmission

Objective:To evaluate the hearing improvement following partially ossicular replacement with different materials. Methods: The CT data of normal ossicle, were digitalized and imported into PATRAN( a world class commercial software. ) to build a 3 dimension finite element model. Then the ossicle model was analyzed based on dynamic transmitting vibration principles and the calculation results were evaluated and compared with various material preferences. Results:The ossicle 3D model established in the present study was in accord with biological structure of the human, the frequency reaction curves obtained by the model proposed in this study agreeed well with the fresh temporal bone ones. This research demonstrated that,with the increasing of elastic modulus,the amplitude of stapes footplate would also increase and get to the amplitude of stapes footplate more closely. After the elastic modulus getting bigger than 115000 gPa,the change rate of amplitude curve would be relatively small,which was almost a horizontal line. Conclusion:The model in this study is nicety. In stead of paying mainly attention to the material density when choosing the artificial replaced body materials in clinic,the physical preferences of the chosen material should focus mainly on the Young's modulus,when the elastic modulus increases so does,the hearing recovering effect,while as the elastic modulus comes to 115000 gpa,which means the elastic modulus arrive at the limit value for the artificial body, the hearing recovering effect no longer gets better.