Statement of the expert group on the current practice and prospects for the treatment of complex perirectal fistulas in the course of Crohn's disease.

Perirectal fistulas in the course of Crohn's disease (CD) constitute an important problem in this group of patients. They are observed in a vast majority of patients with involvement through colorectal inflammation. Perirectal fistulas in CD present a great diagnostic and therapeutic challenge due to the intensified clinical symptoms and worse prognosis than in the case of crypt originating fistulas. The condition for implementation of effective treatment of perirectal fistulas in the course of CD is the correct diagnosis, defining the anatomy of fistulas, presence of potential stenoses and inflammation in the gastrointestinal tract. Treatment of these fistulas is difficult and requires close cooperation between the colorectal surgeon and the gastroenterologist. The combination of surgical and pharmacological treatment has higher efficacy compared to surgical treatment or pharmacotherapy alone. In conservative treatment, aminosalicylates and steroids are of minor importance, while chemotherapeutics, antibiotics, and thiopurines find application in daily clinical practice. TNF-α neutralizing antibodies such as infliximab (IFX), adalimumab (ADA) or certolizumab (CER) prove to be the most effective. Surgical treatment may be provided as ad hoc; in this case, drainage procedures are recommended, usually with leaving a loose seton. Planned procedures consist in the excision of fistulas (simple fistulas) or performing more complex procedures, such as advancement flaps or ligation of the intersphincteric fistula tract Surgical measures can be complemented by the use of video technology (video-assisted anal fistula treatment VAAFT) or vacuum therapy. In extreme cases, it may be necessary to create the stoma. Treatment of perirectal fistulas includes adhesives or so-called plugs. High hopes may be associated with the introduction of stem cells into clinical practice, which is the administration of non-hematopoietic multipotent cells to the fistulas to induce the phenomenon of immunomodulation and tissue healing.