Perianal fistula and the ileoanal pouch - different aetiologies require distinct evaluation

Aim Restorative proctocolectomy has been widely adopted as the procedure of choice for restoring gastrointestinal continuity following proctocolectomy. It is often associated with improved quality of life and high patient satisfaction; however, the development of a pouch anal fistula can cause significant morbidity. Pouch fistulas are notoriously difficult to treat and there is great heterogeneity in the management reported of these fistulas. A lack of classification, and the assumption that fistulas originating from completely different aetiologies will behave and respond similarly to a particular treatment strategy, precludes meaningful comparison of management outcomes. We aim to introduce consistency in the reporting of pouch fistulas using a novel classification system. Methods A consensus process involving clinicians experienced in the management of pouch fistulas from two high volume tertiary centres was performed. Results We propose that pouch anal fistulas should be classified into four distinct groups according to their aetiology: group 1, anastomotic related; group 2, inflammatory bowel disease related, with sub-classifications Crohn's (type A) and non-Crohn's (type B) in origin; group 3, cryptoglandular related; and group 4, malignancy related. Conclusion Classification of pouch fistulas according to their aetiology will provide consistency in the literature and improve the quality of prospective evidence for the management of pouch fistulas.