The Feedback Artificial Sphincter System Based On Rectal Sensation Function Rebuilding

Fecal incontinence is the result of numerous disorders affecting the anatomyand physiology of the anorectum. Clinical symptoms is usually manifests asrecurrent, uncontrolled passage of solid or liquid dejecta or gas. The incidence rate ishigher in elderly patients, critically ill patients, and paraplegic patients. Fecalincontinence not only brings physical and mental sufferings to patients, but alsoincreases difficulties to nursing work. The development of related therapeutic meansand technology has a vital practical significance to improve patients’ life quality andto promote social civilization.Several traditional therapeutic methods can treat fecal incontinence in somedegree, however, with limit effect and amount of drawbacks. So Artificial analsphincter (AAS) has developed a new approach to track with fecal incontinence.Current artificial anal sphincter can’t apperceive the quantity of the feces. For theexisting Artificial anal sphincter, some limitations such as the unintelligent and theloss of rectal sensation function, has become the most sophisticated problem thatrestricts its development. So it needs to be realized urgently to improve theintelligent of Artificial anal sphincter and rebuild rectal sensation function.Based on the National Natural Science Fund of China, the research objectivesof this dissertation is the establish of the Artificial anal sphincter prototype andresearch of rectal sensation rebuilding. Related approach about optimizing of featurevector selection and pattern recognition is discussed. To verify the effectiveness ofthe proposed Algorithm, an integrated experimental platform of rectal sensationfunction rebuilding is established The dissertation can be summarized to four parts,which are the implementation of AAS system, the biocompatibility analysis of thenovel executive mechanism, the theory of rectal sensation function rebuilding andthe establish of experimental platform respectively The research work is mainlyreflected as follows: (1) The dissertation introduces the basis physiological sense and the generalsituation of anal incontinence. The routine treatment for fecal incontinence and thefollowing applications are introduced. Related domestic and foreign research aboutAAS system is studied. Based on the limitation of exiting AAS system, the proposesthe conception of an artificial anal sphincter system based on biological feedbackcontrol.(2) The prototype of AAS system is designed. The dissertation studies thenature anal sphincter muscle group in physiology. Based on anal sphincterrebuilding theory and defecation control mechanism, a prototype is designed tosimulate the basis function of anal sphincter muscle group. The AAS system thatconsists of a novel executive mechanism, a wireless communication module and atranscutaneous energy transmission module is proposed. The structure of theartificial anal sphincter system are based on modeling and low-power consumptionrequirement.(3) Biocompatibility analysis of the novel executive mechanism is researchedto establish the motion model. Relative statics and motion safety, which lay solidfoundation for further research, are achieved based on the model.(4) Feature extraction and classify algorithm of rectal pressure signal is studied.In view of the non-stationary and nonlinear characteristics of rectal pressure signal,feature vector of subspace time-domain and frequency-domain based on optimalwavelet packet basis is proposed to extract. The optimal wavelet packet basisalgorithm is based on DB index to achieve a higher classify accuracy. And theeffectiveness of the feature extraction methods has been verified based on SVMmodel.(5) An in vitro experimental platform of the AAS system is developed andhuman nature intestinal simulation experiment is carried out. With the guidance ofthe above theory and methods, a lot of experimental data is obtained through thesimulation environment. Experimental results verify the effectiveness of the basic module of AAS system and the proposed algorithm. Based on the assessment result,it is possible to improve the AAS system and provide theoretical basis and technicalsupport for fecal incontinence patients in clinic treatment.