中耳病变及人工镫骨形体研究

Research on pathological changes of middle-ear and artificial stapes

目的研究听骨韧带、肌腱硬化和切除以及人工镫骨置换对声音传导的影响。方法基于CT扫描数据,通过自编C++程序读取CT数据中体单元建立人耳结构几何模型,将几何模型导入PATRAN中赋予材料参数、设置关节接触面以及相应其他边界条件生成数值模型。结果利用人耳数值模型进行正常耳和病变耳的谐响应分析,得到正常耳和病变耳镫骨底板和鼓膜凸的振幅变化规律。并由此构建了套型人工镫骨。结论正常耳的模拟结果与实验测试结果吻合,证明了本模型准确性,可以模拟人传声功能。本模型模拟病变耳的计算结果可以从力学角度解释病变对声音传导的影响,为病变耳治疗提供参考。本文的套型人工镫骨较我国临床用的环型人工镫骨更吻合人耳的生理功能,其重建听力效果更好。

Objective To investigate the influence of cirrhosis and detachment of ligaments, tendons and stapes replacement prosthesis on sound transmission for human ear. Method Based on CT data, the geometrical model of human ear is established bya C ＋ ＋ program developed bythe authors. The numerical model is then built up through the finite element software PATRAN where the geometrical model is imported and the material properties, interface of the joints and boundary conditions were defined. Result Amplitude variation laws of the stapes footplate and umbo were obtained by comparing the frequency response analytic results between the normal ear and pathological ear. Moreover, the sheath shaped stapes replacement prosthesis was then constructed based on the analysis of this numerical model. Conclusions The accuracy of the mod- el has been validated bythe well matched computational and experimental results in normal ear, and it can be used to simulate the human sound transmission. The computational results from the pathological ear can explain the effect of lesion for sound conduction from the mechanical view, and provide reference for ear illness treatment. Compared with the effect of ring shaped stapes prosthesis commonly used in China, the sheath shaped stapes replacement prosthesis is more suitable for physiological function of human ear and the hearing recovering effect could be better.