[Anorectal fistulas in Crohn disease]

Anorectal fistulas don't follow the same rules as idiopathic anorectal fistulas do. Their cause and treatment is completely different. Almost 40% of all patients suffering from Crohn's disease show anorectal manifestations. In 10-15% of the cases the anorectal manifestation is the first sign of Crohn's disease at all. 30% of all fistulas heal at least for a while spontaneously. The diagnostic procedures include nowadays anal endosonography and MRI as most sensitive ones and should be added for every work-up of anorectal Crohn. We differ a conservative from a radical therapy. To our opinion every therapy should be adopted to the individual needs of each patient. The most important principle in anorectal Crohn's disease is laying open of the fistula tract and excision of all the diseased tissue. This should be followed either by a drainage seton or by a definitive plastic closure of the fistula (mucosa-muscle flap). For a mucosa-muscle-flap there is only in otherwise disease-free patients and there only for high transsphincteric fistulas an indication. In our own series we treated of 69 patients 59 with a drainage seton and 10 with a mucosa-muscle flap. Recurrence occurred in 6/59 respectively 2/10 of the treated patients. Anovaginal fistulas should due to the high recurrence rate of surgically closed fistulas (> 50%) only be operated if there are serious symptoms such as recurrent vaginal infection, vaginal flatus and permanent vaginal defecations.