Biomechanical Modeling of the Rectum for the Design of a Novel Artificial Anal Sphincter

This paper discusses biomechanical issues that are related to the option of a novel artificial anal sphincter around the human rectum. The prosthesis consists of a compression cuff system inside and a reservoir cuff system outside, which is placed around the debilitated sphincter muscle. The micro-pump shifts fluid between the cuffs and thus takes over the expansion and compression function of the sphincter muscle. However, the human rectum is not a rigid pipe, and motion in it is further complicated by the fact that the bowel is susceptible to damage. With the goal of engineering a safe and reliable machine, the biomechanical properties of the in-vivo porcine rectum are studied and the tissue ischemia is analyzed.