反馈式人工肛门括约肌生物力学相容性研究

Research on biomechanical compatibility for a novel feedback artifical anal sphincter

针对人工肛门括约的直肠感知功能重建和肌生物力学相容性问题,提出将HAPC波作为产生便意的主要依据,利用小波包分析对直肠压力信号进行特征提取,采用DB算法优化后通过SVM分类器进行便意预测,从而实现直肠感知功能重建;构建了直肠和人工肛门括约肌的三维有限元模型,对直肠进行了黏弹性分析,利用直肠的本构方程推导出了Prony级数形式,并模拟括约肌的收缩和舒张施加载荷对人工肛门括约肌进行了有限元分析,得到了直肠受压迫时的位移和应力的分布情况。仿真实验结果表明,该人工肛门括约肌较高精度地实现了便意预测,并具有较好的生物力学相容性。

Aiming at the rectal perception function reconstruction and biomechanical compatibility for artificial anal sphincter, HAPC wave is proposed to be taken as the main signal of defecation intention, the characteristics of rectal pressure signal are extracted using wavelet packet analysis ; then the feature vectors of rectal pressure signal are obtained with DB optimal algorithm, defecation intention is predicted by the trained SVM classifier, and the rectal perception function reconstruction is achieved. The three-dimensional finite ele- ment models of rectum and artificial anal sphincter are established, which are used to perform the rectum viscoelasticity analysis. The Prony series is deduced from the constitutive equation of rectum based on the rectum viscoelasticity analysis result, the finite element a- nalysis of the artificial anal sphincter is carried out through exerting loads simulating the contraction and relaxation of the sphincter. The stress and displacement distribution for the rectum under pressure is obtained; preliminary analysis results of the simulation experiment show that the artificial anal sphincter can predict defecation intention with high accuracy and has good biomechanical compatibility.