Treatment of anal fistula in Crohn's disease

Crohn's disease (CD) is complicated by perianal fistulas in up to 40 % of patients at some time during the course of their disease. Perianal fistulas are particularly frequent when the distal portion of the digestive tract is involved and are one of the most difficult sequelae of Crohn's disease, with an often incomplete response to treatment. The goal of the treatment is symptom relief and improved quality of life in an attempt to cure the lesions, prevent relapse, and reduce the risk of sphincter destruction. Modalities used to diagnose and classify Crohn's perianal fistulas tracks with a high diagnostic accuracy include examination under anaesthesia, pelvic magnetic resonance imaging and endoanal ultrasonography. The classification of the fistula as simple or complex depends on the anatomical fistula track, the activity and the clinical severity of the disease. A combined medical and surgical approach in the management of such patients is the optimal treatment bearing higher success rate. A simple fistula is usually treated by antibiotics and fistulotomy. A complex fistula is often treated by noncutting scions, antibiotics, azathioprine and in many cases by anti-TNF agents such as infliximab. In a second step, fibrin glue or rectal advancement flap can be considered.