Background: The leading cause of pouch failure following ileal pouch-anal anastomosis are peri-pouch fistulas and pelvic sepsis. Objective: Determine the overall efficacy of current surgical therapy for the treatment of perianal and anovaginal fistulizing disease related to Crohn's disease phenotype of the pouch.

Design: Retrospective cohort study of a prospectively maintained, IRB-approved database. Settings/patients: Ninety-one (2.3%) patients of 3058 patients with an original diagnosis of ulcerative colitis who underwent proctocolectomy with ileal pouch-anal anastomosis between 2000 and 2021 at the Cleveland Clinic and underwent postoperative surgery for Crohn's-related perianal disease. Interventions: Two hundred thirty-one operations for perianal or anovaginal fistula(s). Main outcome and measures: Healing rate of surgical therapy for peri-pouch fistulizing disease, impact of recurrent interventions on outcomes, and predictors of surgical failure.

Results: Overall mean age was 39.1 (± 11.6) years, with a BMI of 25.3 (± 6.3) kg/m2. More than half of the patients were female (n = 52, 57.1%). Sixty-three patients (69.2%) had a perianal fistula, 25 (27.5%) had an anovaginal fistula, and 3 (3.3%) patients had both. Overall success rate for healing was 59.3% (n = 54/91) at a mean follow-up of 6.4 (± 4.8) years. Seventeen (18.7%) patients underwent a concomitant diverting loop ileostomy. Among them, eight (47.0%) patients had the ileostomy closure after a mean time of 9.7 (± 2.8) months. In the multivariable logistic regression model, patients who had seton insertions in any operation were significantly less likely to heal (OR 0.11 95%, CI 0.03-0.43, p = 0.001). Overall pouch failure rate was 12.1%. Limitations: Retrospective single-center study which lacks a control arm and consistent long-term follow-up specific to a population-based dataset.

Conclusions: Pouch patients who develop perianal disease are difficult to treat, sometimes requiring pouch excision. However, when medical treatment alone is not effective, a multidisciplinary approach including surgical intervention can result in complete fistula healing in more than half of the cases.