P101 - ACPGBI Traveling Fellow: Retrospective classification of 244 perianal pouch fistulas- Do outcomes of medical and surgical management vary with fistula aetiology?

Saturday, May 9, 2026

12:28 PM - 12:36 PM ET

Abstract Podium Presenter(s)

Lillian Reza, MBBS, MSc, FRCS, PhD candidate

Resident
West Hertfordshire Teaching Hospitals NHS Trust
Imperial College
London, England, United Kingdom

All disclosed relationships have been reviewed and managed prior to the start of this activity. Any relevant relationships will be listed below. This individual has no financial relationships to disclose

Purpose/Background: This study aimed to compare clinical outcomes of perianal pouch fistulas, stratified by aetiology according to the St Mark’s perianal pouch fistula classification system.

Methods
A retrospective study was conducted on patients with pouch anal and/or vaginal fistula between January 2003-2020. Patients were classified according to an aetiological classification system using predefined criteria. Fistula healing, pouch failure rate and time to pouch failure were primary outcomes.

Results
Two hundred forty-four patients ( 61% female) with pouch fistula (anal 39%, vaginal 53%, both 8%) were classified into group 1 anastomotic leak related (35%), group 2a Crohn’s disease (9%), group 2b non-Crohn’s active IBD (30%), group 3 cryptoglandular disease (19%) and group 4 malignancy related fistula (1%). Fifteen (6%) patients could not be classified. Overall fistula healing rate with reparative procedures was 38% (n= 51/133). Overall fistula healing rate with biologics in group 2a and 2b patients was 57% (n=17/30). Among those treated with biologics, 9 (11%) patients were retrospectively classified as belonging to group 1 and showed no response to biologics. Group 1 patients had the highest rate of pouch failure at 66% while group 3 (15%) had the lowest, p <0.001. The odds of pouch failure in group 1 was significantly higher than all other groups at 10.76, (95% CI: 4.51–29.03). Patients with pouch failure in group 1 presented with a fistula at a median 10 months (IQR: 6-29), compared to those without failure at 30.5 (IQR: 8-60), p < 0.049. Kaplan-Meir analysis demonstrated that group 1 patients reached pouch failure status more rapidly than all other groups, p < 0.001.

Conclusion
Aetiological classification of pouch fistula using the proposed criteria may aid patient counselling and disease outcome prediction. Implementation of this classification is an important prerequisite to delivering high-standard care which includes appropriate selection of patients for both biologics and surgical treatment.