Half of patients with perianal fistulising Crohn's disease relapse within 5 years after anti-TNFα discontinuation. Immunosuppressant continuation may decrease this risk. The high risk of relapse (perianal and luminal) may suggest a benefit in pursuing biologics over a longer period in patients with perianal fistulas.

Rectal flap advancement is a satisfactory option for the therapeutic management of anal fistula, including CD populations. Fistula drainage is needed before performing this surgical technique.

Aim To compare the rate of failure of radiofrequency thermocoagulation for anal fistula with that of rectal advancement flap in a case‐matched study. Method Patients who underwent radiofrequency treatment were compared with age‐ and sex‐matched patients with Crohn's disease (CD) who underwent a rectal flap procedure. Fistula features, general characteristics and the main clinical events were recorded in a prospective database. Failure was defined by at least one of following: abscess, purulent discharge, visible external opening or further drainage procedure. Results A total of 62 patients [median age 45 (range 36.8–57.5) years; 22 women, 40 men; 22 with CD] were analysed. The failure rate of radiofrequency treatment was higher than that of rectal flap treatment (74.2% vs 32.2%; P = 0.004). The cumulative probabilities of failure of the radiofrequency treatment were 53.8% (38.8–68.3), 71.8% (55.3–84.0) and 87.4% (70.6–95.3) at 3, 6 and 12 months, respectively. Three patients in the radiofrequency group required drainage for an abscess and one had severe thermal ulceration. The Cox proportional hazards regression model (surgical procedure, obesity, CD) showed rectal flap treatment [3.48 (1.60–8.07); P = 0.001] and CD [2.60 (1.16–6.41); P = 0.02] to be the main independent predictors of healing. Conclusion Radiofrequency thermocoagulation is a less satisfactory sphincter‐sparing treatment for the management of anal fistula than a rectal flap procedure.