Development of a novel, remote-controlled artificial bowel sphincter through microsystems technology.

An artificial sphincter prototype has been developed, specifically designed for comfortable remote control by fecally incontinent patients. The artificial sphincter includes a fluid reservoir, an occlusive cuff, and a micropump based on piezo-technology in a single unit. Continence and implantation management were evaluated around isolated porcine anal canals and in vivo. The design of the prosthesis reduces the occlusion pressure and allows low inflation volumes (6.5-16 mL). Operating pressures between 24 and 58 mm Hg indicate a minor risk of ischemic injury to the bowel. The operation time is estimated at about 7 days with no recharging of the battery. The novel prototype is a highly integrated prosthesis for placement around the anal canal or lower rectum, effecting continence with comfortable control.

[German Artificial Sphincter System--GASS. Development and in vitro evaluation of a novel, fully-implantable, highly integrated sphincter prosthesis for therapy of high-grade fecal incontinence]. / German Artificial Sphincter System--GASS. Entwicklung und in vitro Evaluation eines neuen vollimplantierbaren hochintegrativen Neosphinkters zur Therapie der hochgradigen Stuhlinkontinenz.

No highly integrated sphincter prosthesis for therapy of major fecal incontinence exists. Therefore, we developed a novel neosphincter, made of polyurethane. The GASS consists of a support ring (SR) which includes a fluid reservoir, fixed on the outer diameter of the SR, and a multi-chamber occluding cuff (C(int)) on the inside diameter. The total inflation volume of C(int) is about 23 cc. The integrated micropump based on piezotechnology measures 30x13x1 mm3 (flowrate 1.4 cc/min, max. backpressure 40,000 Pa) . GASS was evaluated around the external sphincter of isolated porcine anal canals. The threshold of continence was defined as the inflating volume which water ceased to leak through the area occluded by C(int) under an induced rectal pressure of 150 cm H2O. Minimal filling volumes maintained continence for liquids against high luminal pressures. A low intraanal resting pressure (delta p(anal)) induced by activated GASS indicates a little risk of ischemic injury of the anal canal in vivo (median delta p(anal) 24.1 mm hg:15 cc vs 46.9 mm hg:21 cc). In summary, a highly integrated and efficient high-tech neosphincter for the therapy of major fecal incontinence could be realized.