No abstract

Artificial anal sphincter (AAS) is an in situ implanted device that acts as a treatment for fecal incontinence regardless of etiology by augmenting the incompetent sphincteric structures. However, AAS is impeded from becoming a valid therapy by its high rate of ischemic complication and malfunction. This article presents an original puborectalis-like artificial anal sphincter (PAAS) that features a low risk of ischemia necrosis and rectal perception remodeling. The device retains continence by reproducing the action, including the pulling and angulating the rectum, of the puborectalis muscle, which forms the anorectal angle and reduces the required clamping pressure. Three rectal pressure sensors were embedded to maintain the pressure exerted on the rectal wall in a safe range and to monitor the distention of the rectum. A series of in vitro studies were conducted with a porcine rectum, and this PAAS prototype manifested the ability of maintaining continence with a clamping pressure considerably lower than that required by other AAS devices. The pressure sensors exhibit good linearity, and the function of rectal perception remodeling has also revealed high reliability with a success rate of 93.3%.

While fecal incontinence (FI) is not fatal, it can dramatically decrease the patient’s quality of life. An artificial anal sphincter (AAS) is an implantable device that treats FI by replacing a diseased or damaged anal sphincter, thus allowing the patient’s continence to be maintained. Here, we report a novel implantable puborectalis‐like artificial anal sphincter (PAAS) that replicates rectal perception and has a low risk of ischemia necrosis. Using the pressure sensors embedded in the PAAS, the relationship between the mass of feces and the pressure was determined, and a feces mass estimation model was developed based on in vitro studies. Rectal perception is provided through the real‐time monitoring of rectal feces, and the feeling of defecation is quantified based on a comparison between the feces mass and a preset threshold mass. In vivo studies were performed for validation, and the accuracy of the model was determined to be as high as 90%. The performance of the PAAS in the real‐time monitoring of rectal feces and its in vivo biocompatibility were also evaluated. The device should further the functionality of existing AAS systems while improving their biosafety and thus expand the applicability of implantable AAS systems in the treatment of FI.

Puborectalis‐like artificial anal sphincter (PAAS) is an innovative new type of artificial anal sphincter (AAS). It overcomes many drawbacks and inadequacies of various previous AASs, and it has successfully been implanted in vivo for almost 3 weeks. During in vivo testing, PAAS shows its ability to retain continence with low risk of ischemia necrosis, and somehow truly helps to remodel rectal perception. However, there are still many defects that influence the long‐term implantation of PAAS, especially in the power supply system (PSS). This article presents a new designed PSS which includes a new transcutaneous energy transfer (TET) system, a heat reduction system, and a safety usage system. The new PSS reduces the total size of PAAS by at least 30%. Newly designed TET system can satisfy the Qi standard, and render a power of 3W to fulfill the requirement of fast charging and normal use of PAAS at the distance of 15.5 mm when frequency of TET system is 110 kHz, which previous TET systems can hardly achieve. Heat reduction system helps to reduce the heat generated during TET charging. It can reduce heat by 40% during the same period of time of TET charging. Safety usage system helps the user control PAAS more properly which can reduce the rate of failure of PAAS system.