不同材料修补不同面积中央性鼓膜穿孔的有限元模型分析

目的利用有限元模型研究不同移植材料修补不同面积中央性鼓膜穿孔对术后听力的影响。方法建立人正常中耳有限元模型,在鼓膜表面施加90 dB SPL声压得到镫骨底板位移的频率-幅度曲线(基准曲线,为正常中耳有限元镫骨底板位移曲线),通过与相关实验数据对比,验证模型可靠性,再建立3.10、10.66、22.25、42.0 mm²中央性鼓膜穿孔有限元模型,分别用0.25、0.5、1 mm厚度耳屏软骨以及0.4、0.8 mm厚度颞肌筋膜修补上述不同面积中央性鼓膜穿孔,获得术后镫骨底板位移频率-幅度曲线,并与基准曲线对比,分析术后听力情况。结果鼓膜穿孔面积3.10 mm²时,不同厚度的耳屏软骨和颞肌筋膜获得的镫骨底板位移均能基本符合基准曲线;穿孔面积10.66 mm²时,不同厚度的耳屏软骨或颞肌筋膜修补获得的镫骨底板位移曲线也基本贴近基准曲线,但0.25、0.5 mm厚度耳屏软骨的位移曲线更符合基准曲线;穿孔面积22.25 mm²时,在低频区域,耳屏软骨比颞肌筋膜获得的镫骨位移曲线与基准曲线的差异更小,在高频区域,0.25、0.5 mm厚度耳屏软骨和0.4 mm厚度颞肌筋膜获得的镫骨位移曲线更贴近于基准曲线;穿孔面积42.0 mm²时,颞肌筋膜和1 mm厚耳屏软骨获得的镫骨底板位移曲线与基准曲线的差异较大,而0.25 mm或0.5 mm厚耳屏软骨差异较小,0.25 mm厚耳屏软骨效果最佳。结论使用耳屏软骨或颞肌筋膜作为移植材料修补较小中央性鼓膜穿孔后镫骨底板位移没有显著差异;随着穿孔面积增大,以较薄的耳屏软骨作为移植材料得到的镫骨底板位移曲线与基准曲线差异最小。

Finite Element Model Analysis of Different Materials for Repairing Central Tympanic Membrane Perforation with Different Sizes

Objective To study the effects of different graft materials repairing different sizes of central tympanic membrane perforation on postoperative hearing with finite element model.Methods A finite element model of the human middle ear was established,and 90 dB SPL sound pressure was applied to the surface of the tympanic membrane to obtain the displacement response curve of the stapes footplate.The reliability of the model was verified by comparison with the experimental data.Different sizes of central tympanic membrane perforation(3.10,10.66,22.25,42.0 mm²)were repaired with 0.25,0.5,1 mm thickness of tragus cartilage or 0.4,0.8 mm thickness of temporalis fascia,and the postoperative hearing condition was analyzed by comparing the postoperative displacement curve of stapes footplate.Results When the tympanic membrane perforation area was 3.10 mm²,the displacement curves of stapes footplate obtained by different thickness of tragus cartilage or temporalis fascia could generally accord with the reference curve(finite element displacement curve of stapes footplate under normal state).When perforation area was 10.66 mm²,the displacement curves of stapes footplate obtained by tragus cartilage of different thickness or temporalis fascia were also generally close to the reference curve,and the displacement curve of tragus cartilage of 0.25 mm and 0.5 mm were better.When perforation area was 22.25 mm²,the difference between the stapes displacement curves obtained by tragus cartilage and the reference curve were smaller than that obtained by temporalis fascia in the low frequency areas.The displacement curves obtained by 0.25,0.5 mm tragus cartilage and 0.4 mm temporalis fascia were closer to the reference curve in the high frequency areas.When perforation area was 42.0 mm²,the displacement curves of the stapes obtained by temporalis fascia and 1mm tragus cartilage were quite different from the reference curve,but the difference obtained by tragus cartilage of 0.25 mm or 0.5 mm were smaller and the 0.25 mm has the best effect.Conclusion Using tragus cartilage or temporalis fascia to repair the smaller central perforation has no significant difference in the displacement of the stapes footplate.As the perforation sizes increases,the displacement curves of the stapes footplate obtained by using thinner tragus cartilage have smaller difference from the reference curve.