A Study Of The Control System And Wirelless Power Transmission Technology Of The Puborectalis-like Artificial Anal Sphincter

Fecal Incontinence(FI)refers to is a particularly distressing symptom that involves the loss of voluntary control of fecal excretion.This condition exerts adverse impacts on those who suffer from it.Social embarrassment,mental status degradation,and loss of quality of life are always associated with FI.The complexity of its etiology makes it almost impossible to find a general therapy suited for every patient,that is,the treatment approach must be tailored to each distinct individual.Therapy for FI typically starts with auxiliary therapies.These therapies are associated with limited clinical benefits,and the indications are restricted to mild symptoms.Regarding severe FI,invasive treatments ranging from surgical repair of the sphincter to sacral nerve stimulation are optional.However,none of the current therapies can retain initial therapeutic successes in long-term evaluation,and the quality of the FI surgical evidence is insufficient for clinical decisionmaking.The high number of options for treating FI means that this problem has not found a satisfactory solution to date.Artificial anal sphincter(AAS)is an in situ implanted device for the treatment for FI regardless of the etiology that augments incompetent sphincteric structures.We developed a puborectalis-like artificial anal sphincter(PAAS)that is based on the hydrodynamics principle that the content can be retained in a tube with only an acute angle instead of complete sealing or squeezing.The specific contributions made by this thesis is list as below:1.The design and fabrication of the puboretalis-like prosthetic sphincter.The design of the motor driver and the actuator.Flexible rectal pressure sensors were designed and fabricated to monitor the rectal pressure and reconstruct the rectal perception of the patient.2.Optimized the TX-RX coils according to the current inductance mathematical model.According to the optimal parameters,the real coils were made and demonstrated a transmission efficiency of 84.91% at the distance between 5 and 25 mm.3.Design of the inner and outer control circuit.Basing on the criteria of energy-sufficient,miniaturized-size and low thermal dissipation,the implantable control circuit was fulfilled on a PCB with diameter of 18.4mm and the power consumption was as low as 0.825 mW in standby mode.4.Design of the control software.Algorithm was designed to fulfill the rectal perception function and pressure-controlled clamping.The wireless communication protocol was optimized to reduce the power consumption by 96.5%.5.Fabrication,in-vitro and in-vivo experiments of the prototype.In-vitro experiments were conducted on a porcine colon and the quantitative relationship between rectal pressure data and the real rectal pressure was derived.An in-vivo experiment basing on Beagle dog was also conducted and the short-term ability of maintaining continence of this system was evaluated.This thesis showed the complete procedure of the design,fabrication and experiments of the puboretalis-like artificial anal sphincter.The feasibility of this system was evaluated and it provides a new therapy for the treatment of FI.