A Portable, Vacuum-Operated, and Purely Mechanical Device for Extracting Feces by Suction to Cure Chronic Anal Fissures

Abstract

An anal fissure is a common anorectal problem that affects men and women of all age groups. It initiates with an acute stage that presents as a linear or oval tear in the anoderm and may progress to a more complex chronic stage due to poor healing. Routine defecation causes overstretching of the injured anoderm which deepens the injury resulting in hypertonicty and ischemia, setting up a positive feedback loop that keeps the fissure from healing. Existing treatments can be invasive, expensive, and may include side effects. Here we present a novel vacuum-operated mechanical device to extract feces via suction. The device is designed to solve the problem of anodermal stretching by assisting in defecation. The device was tested in vitro on a benchtop model of the rectum and in vivo on live pigs. in vitro tests showed that the device could hold vacuum pressures for 12 h with negligible leakage. Further, the device could extract simulated human feces at a flowrate of 32 mL/s. in vivo tests on pigs showed that the device did not cause any trauma to the rectal wall, thus demonstrating its safety. Our results highlight the potential of this novel platform to circumvent the problem of anodermal stretching and improve the healing rate of anal fissures.