Periproctic abscess and anal fistula

Infected anal crypts are the focus of periproctic abscesses. The resulting fistulas are characterized by an internal and external opening and a granulating duct. Parks' classification is well established. Abscesses should be lanced and drained in emergency cases. Uncomplicated deep fistulas should be operated on during the same procedure. For the treatment of high inter-, supra-, and extrasphincteric fistulas, transitory Seton drainage is recommended. After preoperative diagnosis and careful planning the fistula should be excised completely and the internal opening should be closed by a mucosa flap. In certain cases the external opening can be closed as well. Anal fistulas of Crohn's disease are characterized by complex extension. Inflammatory processes have to be operated on in Crohn's disease as well.