Design of an Actuator for Artificial Anal Sphincter Based on Finite Element Analysis

In order to restore the normal function of anus in patients with anal incontinence, a new artificial anal sphincter system has been proposed. In this paper, a new actuator of the artificial anal sphincter system was designed, and the part of the cushion directly in contact with the rectum was designed into an arc structure. The actuator can completely clamp the rectum without causing the intestinal tissue to be necrotic due to excessive stress. Three-dimensional finite element models of the rectum and the actuator were constructed. After simulating the contraction and relaxation of the sphincter, displacement diagram and stress diagram of the rectum being pressed could be obtained. The simulation results show that the maximum stress of the rectum being pressed is 25. 337KPa, and more than 84% of the area is below lOKPa, which is the driving pressure threshold of the normal mesenteric blood vessels of the rectum. Therefore, the actuator has good biomechanical compatibility.