A fistula forms a connection, a kind of passageway, between the skin around the anus and the rectum. Fluid and pus drains through the so-called fistula duct. The fistula can have a direct course to the rectum, but can also be very complicated, for example tortuous and possibly with side branches. Depending on the extent of the fistula formation, laser or surgical treatment will take place. Sometimes several treatments are needed to reach a definitive solution.