Research On Key Technologies Of In Situ Implantable Artificial Anal Sphincter

Incontinence, also known as fecal incontinence, refers to that since anal sphincter cannot be controlled by consciousness and cannot perceive the capacity and quality of the contents of the rectum, people cannot defecate automatically. This situation will make people lose self-control and be self-isolated, and their quality of life will seriously decline. To completely resolve the problem of self-defecation, such as the absence of anal sphincter and severe damage of a patient's bowl, artificial anal sphincter is a quite promising area of research. The artificial anal sphincter system which is based on the existing urethral sphincter improved, based on piezoelectric ceramic type or based on shape memory alloy has weaknesses. Therefore, the development of a new type of artificial anal sphincter system which lines with human physiological needs is of great significance.Supported by National Natural Science Fund of China (NO.30800235), a grant from the Ph.D. Programs Fund for New Researchers of Ministry of Education of China (NO.20070248094) and Medicine-Engineering Crossed Fund of Shanghai Jiao Tong University (NO.YG2009ZD103), combining the engineering technology and medical knowledge, this thesis researches the rebuilding theory and key technologies of artificial anal sphincter satisfying for the requirements of body physiology. The final purpose is to work out a new method and device for fecal incontinence treatment, make patients be sure of controlling the defecation time autonomously and eliminate the disadvantages of current fecal incontinence surgery, to improve the quality of people's life.Based on normal defecation mechanism, this thesis studies the key technologies of in situ artificial anal sphincter system, and introduces the overall structure and function of artificial anal sphincter system. The system is composed of two parts, one is the in vitro equipment and the other is portable in vivo equipment. The integrated modules are as follows: perceived functional module, wireless communication module, microcontroller module, micro-executive agencies and transcutaneous energy transmission system. Two new types of micro pumps are put forward in the micro-executive agencies: bellows-type micro-injection pump and peristaltic micro pump. The design principles are introduced.This thesis focuses on the study of transcutaneous energy transmission technology principle, and analyzes SS and SP topologies in the receiving part. The conditions under which the transmission efficiency is highest are put forwarded. The coupling coils design and the circuit design of the transmitter and receiver module are proposed. Finally, the human body's electromagnetic security is studied.In this thesis, the feasibility of the prototype of the artificial anal sphincter system is verified by separate module experiments and the in vitro experiment. First, the experiments of wireless communication module, transcutaneous energy transmission module and micro executive agencies are carried out. The pig intestine is used to simulate the real environment of human intestinal tract, and the effectiveness of the in situ implantable artificial anal sphincter system is verified.