Preservation of the anal transition zone in ulcerative colitis. Long-term effects on defecatory function.

Introduction: The anal transition zone (ATZ) after ileal pouch anal anastomosis (IPAA) for ulcerative colitis is considered at risk for dysplasia and persistent or recurrent disease activity. The long-term fate of the ATZ and the effects of histologic changes on defecatory function are not well-known.

Methods: To evaluate the inflammatory and preneoplastic changes of the ATZ in patients without preoperative dysplasia, yearly biopsies of the ATZ were obtained and functional results recorded on a questionnaire/diary.