An anal fistula is a tunnel that runs from inside the anus -- the hole your body uses to get rid of solid waste -- to somewhere in the skin around it. It usually follows an infection that didn’t heal the right way. Your doctor can repair the fistula, but you'll need surgery for that.
What Causes It?
Just inside your anus are several glands that make fluid. Sometimes, they get blocked or clogged. When that happens, a bacteria buildup can create a swollen pocket of infected tissue and liquid. Doctors call this an abscess.
If you don’t treat the abscess, it’ll grow. Eventually, it’ll make its way to the outside and punch a hole in the skin somewhere near your anus so the gunk inside it can drain. The fistula is the tunnel that connects the gland to that opening.
Most of the time, an abscess causes a fistula. It’s rare, but they can also come from conditions like tuberculosis, sexually transmitted diseases, or an ongoing illness that affects your bowels.
What Are the Symptoms?
The most common ones are:
Swelling around your anus
What are the treatments for fistula?
Surgery is almost always necessary to cure an anal fistula. The surgery is performed by a colon and rectal surgeon. The goal of the surgery is a balance between getting rid of the fistula while protecting the anal sphincter muscles, which could cause incontinence if damaged.
Fistulas in which there is no or little sphincter muscle involved are treated with a fistulotomy. In this procedure, the skin and muscle over the tunnel are cut open to convert it from a tunnel to an open groove. This allows the fistula tract to heal from the bottom up.
In the case of a more complex fistula, the surgeon may have to place a special drain called a seton, which remains in place for at least 6 weeks. After a seton is placed, a second operation is almost always performed:
A fistulotomy, or
An advancement flap procedure (the fistula is covered with a flap, or piece of tissue, taken from the rectum, like a trap door), or
A lift procedure (the skin above the fistula is opened up, the sphincter muscles are spread, and the fistula is tied off).
A new treatment for Crohn’s disease fistulas is to inject stem cells into the fistula. Your colorectal surgeon will discuss all of your options before the surgery.
Fistula surgery is usually done on an outpatient basis, which means the patient can go home the same day. Patients who have very large or deep fistula tunnels may have to stay in the hospital for a short time after the surgery. Some fistulas may require several operations to get rid of the fistula.