In medicine, fistulas are tube-like passageways that either form abnormally or are surgically created in the body. A fistula may connect to organs or vessels, or it might connect the surface of the skin to an internal organ or vessel. Fistulas may form abnormally in the body as a result of disease.

Generally, a fistula is described by its location in the body. For example, an arteriovenous (AV) fistula connects an artery and a vein. AV fistulas are also a good example of a surgically created fistula intended for prolonged medical treatment, such as dialysis in patients with end-stage kidney failure.

Fistulas can form anywhere in the body, and there are three basic types, referred to as blind, complete, and incomplete. Blind fistulas have only one open end, while complete fistulas have openings externally and internally. Incomplete fistulas have an external opening but don’t attach to anything.

The causes of fistulas are varied. Diseases can cause fistulas, as can certain medical treatments and trauma or injury to the body. Conditions such as Crohn’s disease and colitis are common inflammatory bowel diseases that cause anorectal fistulas. Trauma to the body, such as prolonged, severe childbirth, which can cause obstetric fistulas, can also be a culprit. The formation of fistulas as a result of severe childbirth occurs most often in parts of the world where professional medical care is either poor or non-existent.

Treatment of fistulas varies with the cause, location, size, and type. Some small fistulas resulting from injury heal on their own in time. In some cases, if a disease or condition, such as an infection, causes fistulas, then treatment may involve antibiotics. If the fistula interferes with normal and necessary bodily functions, like blood flow, surgery to repair the fistula may be necessary. Diagnosis of fistulas varies with the location and type. Surgically created fistulas typically require a vascular surgeon and are closely monitored for healing and functionality.