A fistula is an opening that forms between two parts of the body that are not normally connected. Usually it is when the vagina opens up into the bladder or the rectum. This can allow urine or stool to come out of the vagina. The exact symptoms will depend on the location of the fistula. Only about 1 out of a thousand people who have surgery will have a fistula. This is very rare. Sometimes a fistula will heal by itself, but most people need surgery to fix it.