**6. Anal fistula in Crohn's disease**

We can say that fistulas associated with Crohn's disease present a special entity in the treatment of anal fistulas. This kind of fistula presents a huge challenge for surgeons despite numerous surgical possibilities and technical advancements in recent years. Symptoms associated with Crohn's anal fistula include purulent drainage, severe pain, possible continence disturbance which all can lead to a significant reduction in quality of life. These kinds of fistulas are often recurrent and hard to treat. The incidence of anal fistulas in patients with Crohn's disease is 5 to 40% and is more common in patients who have a higher severity of colorectal inflammation [69–71].

Even though numerous surgical techniques have been described for the treatment of this kind of anal fistulas, the choice of which technique is best often depends on the anatomy, presence of local inflammation, type of fistula, and surgeon's experience (**Figure 11**) [72–74].

Many management proposals have been published, but all had higher reports of postoperative complications such as continence disturbance, infection and high recurrence rate compared to the same type of fistulas not associated with Crohn's disease. Currently, numerous novel surgical sphincters preserving techniques are being

#### **Figure 11.**

*Perianal form of Crohn's disease in female patient: multiple treatment methods combined (fistulotomy with marsupialization, seton placement, VAAFT).*

studied to less invasively induce fistula healing while maintaining fecal continence. When we discuss surgical treatment of complex anal fistulas in Crohn's disease, the goal should be to ameliorate symptoms associated with this kind of fistulas and to improve patients' quality of life. Although, various endoscopic and surgical techniques exist, there is no gold-standard treatment strategy for patients with perianal fistulas [44, 47, 75, 76].

Treatment of Crohn's disease-associated anal fistula should always be multidisciplinary including surgeons, radiologists and gastroenterologists with the use of antibiotics, immunosuppressors and anti-inflammatory agents [77–81].

General principles in the treatment of this condition are underlined here, but the treatment of an anal form of Crohn's disease is a complex topic, requiring a chapter on its own.
