基于肠道动力学仿真的 AAS 设计及便意感知重建

人造肛门括约肌(AAS)是一种用于治疗大便失禁(FI)的可植入医疗设备,现有的AAS在生物安全性和肠道内容物感知方面存在缺陷,故临床应用受限。首先,结合肠道动力学特性,建立直肠组织的超弹性模型,利用ANSYS进行有限元分析,模拟假体闭合肠道的过程。其次,根据仿真结果,提出了一种嵌入10路压力传感器的新型连杆式人造肛门括约肌结构。最后,进行离体实验和活体动物实验。实验结果证实,仿真模型建立准确,所设计的括约肌假体在血供安全压力内可控便200g,满足人体正常生活需求。10路压力传感器位置分布合理,测量结果线性度良好。离体实验中肠道内容物质量预测的准确性达89.69%,活体实验中排便预警准确性达82%,初步重建了FI患者直肠的便意感知。

AAS design based on intestinal simulation and reconstruction of defecation perception

Artificial anal sphincter (AAS) is an implantable medical device used to treat fecal incontinence ( FI). The existing AAS equipment has shortcomings in biological safety and intestinal content perception, which limits its clinical application. Firstly, a hyperelastic model of rectal tissue was established combined with the characteristics of intestinal dynamics, and ANSYS was used for finite element analysis to simulate the process of closing the intestine with the prosthesis. Then, based on the simulation results, a new connecting-rod artificial anal sphincter structure embedded with 10 sets of pressure sensors was proposed. Finally, in vitro experiments and live animal experiments were carried out. The experimental results confirm that the simulation model is established accurately, and the sphincter prosthesis can control 200 g feces and meet the normal life needs of human body within the blood supply safety pressure threshold. The 10 sets of pressure sensors are reasonably distributed, and the measurement results have good linearity. The accuracy of intestinal content quality prediction in vitro experiments is 89. 69% , and the accuracy of defecation warning in live animal experiments is 82% , which can preliminarily reconstruct the rectum perception of FI patients.