[Effectiveness of Mucosal Advancement Flaps in Surgery of Perianal Fistulas from Crohn´s Disease and Cryptoglandular Fistulas - a Long-term Follow-up Study]. / Effektivität von Mukosa Muskel Flaps in der Behandlung von perianalen Fisteln bei Morbus Crohn und kryptoglandulären Fisteln ­ eine Langzeit-Follow-up-Studie.

AIM: Surgical treatment of perianal fistulae originating from Crohn's Disease (CD) or cryptoglandular abscess (CGA) remains a challenge. Data on long-term healing rates are scarce. We aimed to evaluate the long-term success rate of mucosal advancement flap (MAF) operations. METHODS: This single centre retrospective analysis was performed at a tertiary referral centre (Charité University Hospital Berlin, Campus Benjamin Franklin) between March 1, 2010 and March 31, 2020. Patients with complex perianal fistulae originating from CD or CGA treated with MAF were included. Long-time healing rates of MAF in CGA and CD were compared. Regression analysis was used to identify predictive factors for definitive healing. RESULTS: 83 patients (24 CD, 59 CGA,) were included. Median follow-up for CD was 5.4 and 1.9 years for CGA. Definitive healing of fistulae was achieved in 19 (79.2%) CD patients (p = 0.682) and in 44 (74.6%) CGA patients. Healing time was significantly shorter in CGA than in CD (9.3 months [standard deviation: SD= 11.3 months] vs. 30.9 months [SD = 23.5 months]; p < 0.001). Treatment with biologicals (hazard ratio: HR = 0.18, 95%-confidence interval: 95%-CI = 0.06-0.59, p = 0.004) and diverting ileostomy (HR = 0.29, 95%-CI = 0.10-0.85, p = 0.023) in CD were independent predictors for MAF success. Simultaneous medication with azathioprine in CD was an independent predictor for MAF failure (HR = 3.20, 95%-CI = 1.05-9.81, p = 0.041). CONCLUSION: This study demonstrates that surgical therapy of perianal fistulae with MAF is successful in about 75% of patients overall. Patients with MC benefit from biologicals and a diverting ileostomy. Treatment with azathioprine had a negative impact on recurrence rates. Repeated MAF operations did not increase the risk of failure in subsequent operations.