A novel artificial anal sphincter system based on transcutaneous energy transmission

For controlling anal incontinence,a new artificial anal sphincter system (AASS) with sensor feed-back based on transcutaneous energy transmission is developed.The device mainly comprises an artificialanal sphincter (AAS),a wireless power supply subsystem,and a communication subsystem.The artifi-cial anal sphincter comprises a front cuff and a sensor cuff placed around the rectum,a reservoir sited inabdominal cavity and a micropump controlling inflation and deflation of the front cuff.There are two pres-sure sensors in the artificial anal sphincter.One can measure the pressure in the front cuff to clamp therectum,the other in the sensor cuff can measure the pressure of the rectum.Wireless power supply sub-system includes a resonance transmit coil to transmit an alternating magnetic field and a secondary coil toreceive the power.Wireless communication subsystem can transmit the pressure information of the artifi-cial anal sphincter to the monitor,or send the control commands to the artificial anal sphincter.A proto-type is designed and the basic function of the artificial anal sphincter system has been tested through ex-periments.The results demonstrate that the artificial anal sphincter system can control anal incontinenceeffectively.

Challenges faced in the clinical application of artificial anal sphincters

Fecal incontinence is an unresolved problem, which has a serious effect on patients, both physically and psychologically. For patients with severe symptoms, treatment with an artificial anal sphincter could be a potential option to restore continence. Currently, the Acticon Neosphincter is the only device certified by the US Food and Drug Administration. In this paper, the clinical safety and efficacy of the Acticon Neosphincter are evaluated and discussed. Furthermore, some other key studies on artificial anal sphincters are presented and summarized. In particular, this paper highlights that the crucial problem in this technology is to maintain long-term biomechanical compatibility be- tween implants and surrounding tissues. Compatibility is affected by changes in both the morphology and mechanical properties of the tissues surrounding the implants. A new approach for enhancing the long-term biomechanical compatibility of implantable artificial sphincters is proposed based on the use of smart materials.

Coupling analysis of transcutaneous energy transfer coils with planar sandwich structure for a novel artificial anal sphincter

This paper presents a set of analytical expressions used to determine the coupling coefficient between primary and secondary Litz-wire planar coils used in a transcutaneous energy transfer(TET) system. A TET system has been designed to power a novel elastic scaling artificial anal sphincter system(ES-AASS) for treating severe fecal incontinence(FI), a condition that would benefit from an optimized TET. Expressions that describe the geometrical dimension dependence of self- and mutual inductances of planar coils on a ferrite substrate are provided. The effects of ferrite substrate conductivity, relative permeability, and geometrical dimensions are also considered. To verify these expressions, mutual coupling between planar coils is computed by 3D finite element analysis(FEA), and the proposed expressions show good agreement with numerical results. Different types of planar coils are fabricated with or without ferrite substrate. Measured results for each of the cases are compared with theoretical predictions and FEA solutions. The theoretical results and FEA results are in good agreement with the experimental data.

Artificial Anal Sphincter with Sensor Feedback Powered by Transcutaneous Energy Transmission

This artificial anal sphincter (AAS) is used to help patients who are in severe incontinence. It consists of two parts. The first part is taken outside with patients. The second is implanted in the bodies to provide independent evacuation for patients. It is powered through transcutaneous energy transmission by the first part. There are two sensors in the second part. One sensor measures the pressure in the cuff-clamp around the recta. The other measures the pressure of the recta. As soon as the pressure measured by the later reaches the threshold, a signal is sent out to patients through wireless communication to alarm patients preparing defecation. Patients can give a start signal to begin defecating after they are ready. And they can also give a signal to stop defecating like a healthy person. With the aids of the novel medical device, patients can defecate as a healthy person. The first generation of this AAS is presented.

Electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter system

This paper reports on the electromagnetic effects on the biological tissue surrounding a transcutaneous transformer for an artificial anal sphincter.The coupling coils and human tissues,including the skin,fat,muscle,liver,and blood,were considered.Specific absorption rate (SAR) and current density were analyzed by a finite-length solenoid model.First,SAR and current density as a function of frequency (10–107 Hz) for an emission current of 1.5 A were calculated under different tissue thickness.Then relations between SAR,current density,and five types of tissues under each frequency were deduced.As a result,both the SAR and current density were below the basic restrictions of the International Commission on Non-Ionizing Radiation Protection (ICNIRP).The results show that the analysis of these data is very important for developing the artificial anal sphincter system.