Advancement flaps in perianal fistulizing Crohn’s disease: technical steps and current evidence

Fistulizing perianal Crohn's disease is complex and negatively affects quality of life. Rectal advancement flap (AF) has been widely adopted as a sphincter-preserving procedure for treating complex anal fistulas. The European Crohn's and Colitis Organisation (ECCO) guidelines on surgical treatment of Crohn's disease state that AF is a therapeutic option for patients with Crohn's disease and complex perianal fistulas. Despite its use in clinical practice, documented use of AF in treating fistulas related to Crohn's disease remains limited. This narrative review aimed to examine the latest literature and discuss current evidence for the surgical treatment of fistulizing perianal Crohn's disease using AF procedures. A PICO search was conducted in the electronic databases PubMed, Embase, and Google Scholar to identify studies published in English on the topic between 2018 and November 2025. In total, 11 studies were identified, including 305 patients with Crohn's disease. Most patients received a draining loose seton prior to the AF procedure, while the proportion of patients on biological therapy or with a diverting stoma varied greatly. Reported success rates for clinical healing ranged from 23% to 91%, with median follow-up times reported between 7 months and 6 years (total range: 2 months to 10 years). Despite the inherent limitations of mostly retrospective and small studies, the available evidence supports the feasibility of AFs in fistulizing perianal Crohn's disease, provided there is adequate fistula drainage and, importantly, optimized biological therapy to minimize luminal and perianal inflammation.