Functional Disorders of the Ileal-Anal Pouch: A Systematic Review

BACKGROUND: The IPAA is a boon to patients needing proctocolectomy but maintains per anal function through anatomic and physiologic compromises. The state of pouch function is hard to define because pouch anatomy is not normal and pouch physiology is a distortion of normal defecation. Patients with pouches develop multiple symptoms: some are expected, some are disease related, and some are the result of surgical complications. It is important to understand the cause of pouch-related symptoms so that appropriate management is offered. OBJECTIVES: The study aimed to review pouch symptoms and discuss their likely cause, review the literature on pouch function and dysfunction, and provide clarity to clear the confusion. DATA SOURCES: PubMed and Cochrane databases were searched using the terms "ileoanal pouch function" and "ileoanal pouch dysfunction." STUDY SELECTION: From 1983 to 2023, 553 articles related to "ileoanal pouch function" and 178 related to "ileoanal pouch dysfunction" were reviewed. Nine studies appeared under both headings. Case studies, duplicate publications, and articles concerning pouch diseases were excluded. MAIN OUTCOME MEASURES: Definitions of pouch function and dysfunction, methods of describing and scoring symptoms, and understanding of expected changes in pouch function given the nature of the surgery. RESULTS: Twenty-seven studies were reviewed from the ileoanal pouch dysfunction search and 38 from ileoanal pouch function. Three studies tried to define normal pouch function, 10 attempted to measure pouch function, and 4 aimed to score pouch function. Only 3 studies addressed pouch physiology. LIMITATIONS: A full discussion of pouch dysfunction is limited by the lack of studies focussing on the anatomic and physiologic consequences of turning the terminal ileum into an organ of storage. CONCLUSIONS: Most studies of pouch function and dysfunction do not consider expected changes in the physiology of defecation that follow restorative proctocolectomy. Thus, most studies of pouch function produce conclusions that lack an important dimension. See video from symposium.