What happens if an anal fistula goes untreated for a year?

Abscess: An anal fistula is a connection from the inside of the anorectal area to the outside. This will cause soiling and infection. If left untreated it will lead to perirectal abscess formation and sepsis.

It can worsen: Fistulas are touch little infections because we have to work very hard to preserve the anal sphincters. The simpler the tract, the easier and less risky the surgery. The longer you go without treatment, the more likely that that tract can become more complex and more difficult to safely treat.