An anal fistula (also known as fistula-in-ano) is characterized by chronic purulent drainage through a formed tract typically from an abscess cavity around the anus or rectum. As the pus drains, a small tunnel is created between the skin and abscess cavity. Patients commonly seek treatment due to presence of pain, swelling, and a foul-smelling discharge.
In the early 2000s, the concept of the anal fistula plug was introduced. Specifically, Cook Biotech developed a fistula plug manufactured from porcine small intestinal submucosa meant to be introduced into the fistula tract and allow for the patient’s own healing mechanisms to promote closure of the tract. Interestingly, this material was initially designed to help fill large defects in the abdominal wall; however, a group of surgeons elected to roll the material into a cone shape and insert it into an anal fistula.
Since the fistula plug is a bioprosthetic material, it is appropriate for placement in infected fields making it highly suitable for fistula disease. Many studies have reported data on fistula plugs and the results have been mixed. Some analyses indicate a fistula closure rate of more than 80% as well as a much higher fistula closure rate with the fistula plug when compared to fibrin glue.
On the other hand, some data suggests that fistula plug may only be effective 40-50% of the time. It is important to recognize that the risk of incontinence with use of the fistula plug is minimal. Of note, Cook biotech has since released a Recto-vaginal fistula plug set which is also manufactured from porcine small intestinal submucosa.