Definition: A fistula is an abnormal tunnel connecting two body cavities (such as the rectum and the vagina) or a body cavity to the skin (like the rectum to the outside of the body). A perianal fistula is one that connects the perianal skin with the anus or the rectum.
A fistula may form when an abscess (a pocket of pus in the body) does not heal and eventually breaks through to the skin, another body cavity, or an organ. Fistulas are more common with Crohn's disease than with ulcerative colitis; about 25 percent of people with Crohn's disease develop a fistula.
Crohn's and Colitis Foundation of America. "Surgery for Crohn's Disease." CCFA Mar 2006. 17 Jul 2007.
Pronunciation: (per-ee-AY-nul FIST-yoo-luh)