Anal fistulas are inflammatory tracts that extend from the mucosal lining of the anal opening to the skin around the anal opening. The presence of fistulas results in pain, pus discharge, and skin irritation. The condition is associated with significantly reduced quality of life. The majority (90-95%) of anal fistulas are of cryptoglandular origin, arising as a result of inflammation in an anal gland. The second most common cause of anal fistulas is the chronic inflammatory bowel disease Crohn’s disease, where fistulas occur due to inflammation of the intestinal mucosa itself.
The treatment of complex anal fistulas is often challenging, and surgical closure of the fistula depends on the ability to perform a procedure that preserves the function of the anal sphincter, as damage to this structure carries a risk of subsequent fecal incontinence. Such sphincter-preserving procedures are only possible if the fistula and any extensions are adequately drained and no large extensions are present.
In patients with anal fistulas due to Crohn’s disease, there is convincing evidence of a beneficial effect of anti-inflammatory anti-TNFα therapy. Therefore, anal fistulas in these patients are treated with a combination of surgical drainage and anti-TNFα therapy. This project will investigate if patients with complex cryptoglandular anal fistulas will benefit from anti-TNFα therapy as an add on to the current standard treatment, which consists of surgical drainage alone.