Research On Implantable Gastrointestinal Stimulating System Based On Wireless Charging Technology

Gastrointestinal electrical stimulation (GES) is a new method oftreatment to diseases of the gastrointestinal tract.Studies have shown thatGES has good curative effect in gastrointestinal motility, promoting gastricemptying, gastrointestinal function recovery,in the treatment of obesity andso on. But in clinical applications,Gastrointestinal electrical stimulationmethod is still limited by existing treatment equipments, mainly manifestingin two aspects: On the one hand, its power supply has a limited life span,resulting that patients need secondary surgery to replace the batterypain,meantime,casuing a limited range of treatment pulse parameters;On theanother hand,The lack of an effective methods to detect the result of theelectrical stimulation to the gastrointestinal. With The functionalgastrointestinal disorders and obesity becoming more and more common, todevelop multifunctional implantable gastrointestinal electrical stimulationsystem has become an important research direction in gastrointestinalelectrical stimulation therapeutic area.Under Supported by Medicine-Engineering Crossed Fund of ShanghaiJiaotong University (NO.YG2010MS75) combining the engineeringtechnology and medical knowledge, this paper researches the keytechnologies of multi-functional implantable gastrointestinal electricalstimulation system and in vivo experiment of this system. Analysis theshortcomings of the existing treatment equipment and research the keytechnologies of the new generation of implantable gastrointestinal electricalstimulation system,which plays a further role in diagnosis and treatment offunctional gastrointestinal disorders electric stimulation.The developedsystem is valuable both in research and social benefits. The paper presents a novel implantable gastrointestinal electricalstimulation system solution based on wireless charging technology. Thesystem consist of by the implantable stimulator in vivo, in vitro controller,wireless charging device and host computer software. The implantablestimulator in vivo lives out the function of four lead gastrointestinal electricalstimulation, while achieving a bio-feedback-control by detecting theintestinal electrical signal and pressure signal to adjust the electricalstimulation effect in real-time; The vitro controller is responsible for thetransmission of the control command as well as the detection and storage ofthe feedback data; Wireless charging device supplies electric energy for theimplantable stimulator in vivo, thus avoiding the frequent replacement ofbattery to patient’s suffering; PC data processing software carries out thefunction of the interface control and subsequent data reprocessing.This paper elaborates the specific gastrointestinal electrical stimulationsystems research work from the following aspects:First, the dissertation introduces the mechanism of the gastrointestinalelectrical stimulation method;summarizes the research results achieved innon-organic-lesion gastrointestinal disease treatment.Analyze the research status of existing gastrointestinal electricalstimulation and present design idea of the new type of implantablegastrointestinal electrical stimulation system based on wireless chargingtecnnology. Aiming at the inadequacies of existing gastrointestinal electricalstimulation system, the system designs corresponding module functionmodule to solve several major technical bottleneck problem of thegastrointestinal electrical stimulation system’s clinical applicationSecondly, based on the analysis of the research status system solutionsand design specifications, the author further raised the overall design of thesystem and design the hardware and software of the device in vivo and invitro modulely according to modules;complete the corresponding modulecontrol programming and debugging. This paper focuses on the key technicaldesign and mainly analyze the biological feedback control, wireless charging system,clock control as well as the realization of the current detectionfunction.Finally, according to the design of the overall system and modules,theauthor complete the system prototype preparation.Do some experiments inpercutaneous wireless charging,the intestinal electrical signal and thepressure signal to test the system prototype’s performance. In vitroexperiments, the system can effectively detected2cpm~20cpm simulatedintestinal electrical signals and achieve modifing real-time stimulationparameters to change the output of different stimulus pulse.The systemachieves the current detection function as the part of the monitoring role ofthe gastrointestinal resistance, as well as the role of the current effectproviding a reference for the futural constant current stimulus mode.Theexperiment has verified that when percutaneous wireless energy transmit inthe two coils with their axial distance of22mm, the maximum receivingcharge stability power is0.93W, the lithium-ion in vivo charging current canachieve180mA~240mA,which meets the implantable stimulatorpercutaneous requirements for energy.The experiments in vitro has proved the validity of the gastrointestinalelectrical stimulation system design,which lays the foundation for animalexperiments and subsequent clinical applications of implantablegastrointestinal electrical stimulator based on wireless charging technology.Finally, the author summarized the paper work and experimental results, andPuts forward an direction of improving system and the significance of furtherstudy.