Healing of rectal advancement flap for anal fistula in patients with and without Crohn’s disease: a retrospective cohort analysis

Background Surgical closure of anal fistulas with rectal advancement flap is an established standard method, but in some cases, it has a high degree of healing failure. There are few studies in literature with a small number of cases examining differences between patients with and without Crohn's disease (CD). The aim of this study was to identify risk factors for anal fistula healing failure after advancement flap between patients with cryptoglandular fistulas and patients with CD. Methods From January 2010 to October 2020, 155 rectal advancement flaps (CD patients = 55, non-CD patients = 100) were performed. Patients were entered into a prospective database and retrospectively analyzed for healing rates. Results Median follow up was 189 days (95 % CI: 109–269). Overall complication rate was 5.8 %. Total healing rate for all rectal advanced flaps was 56 %. CD patients were younger (33 vs. 43 years, p < 0.001), more often female (76 vs. 30 %, p < 0.001), had more immunosuppressant medication (65 vs. 5 %, p < 0.001), more vaginal fistulas (29 vs. 8 %, p = 0.001) and more protective stomas (49 vs. 2 %, p < 0.001) than patients without CD. However, there was no difference in the healing rate of patients with or without CD (47 % vs. 60 %, p = 0.088). Conclusions Patients with anal fistulas without and with Crohn’s disease have the same healing rate. Although patients with CD differ in their patient-specific characteristics, no independent factors for the occurrence of anal fistula healing failure could be determined. Trial registration: Not applicable due to the retrospective study design.