Preoperative terminal ileal and colonic resection histopathology predicts risk of pouchitis in patients after ileoanal pull-through procedure

Objective: This study seeks to compare the histopathology of preoperative terminal ileal and colonic resection specimens with pouch biopsies after the ileoanal pull-through (IAPT) procedure. Summary Background Data: Pouchitis is the most frequent complication of transanal continent reservoirs in patients after IAPT. Methods: The authors conducted 751 consecutive pouch biopsies on 73 patients with inflammatory bowel disease or familial adenomatous polyposis who underwent IAPT by a single surgeon over a 10-year period. In this preliminary report, a pathologist, in blinded fashion, has graded 468 of the IAPT pouch biopsies and 67 of the patients' preoperative terminal ileal and colonic resection histopathology to date. Colonic histopathology was graded by the extent and severity of disease, terminal ileal and pouch histopathology by active inflammation, chronic inflammation, lymphocyte aggregates, intraepithelial lymphocytes, eosinophils, and villous blunting. Results: Extent of colonic disease (gross and microscopic) was a significant predictor of active inflammation in subsequent IAPT pouch biopsy specimens. Also, the gross extent of colonic disease exhibited a significant linear association with pouch inflammation. However, the severity of colonic disease was not significantly predictive of active inflammation in subsequent IAPT pouch biopsies. Terminal ileal active and chronic inflammation were significant predictors of subsequent IAPT pouch inflammation. Although lymphocyte aggregates and intraepithelial lymphocytes were not predictive, terminal ileum eosinophils and villous blunting were significant predictors of active inflammation in subsequent IAPT pouch biopsy specimens. Conclusions: Preoperative terminal ileal and colonic histopathology predicts active inflammation of pouches after IAPT. Patients who are preoperatively assessed to have extensive disease of the colon, ileal disease ('backwash ileitis') or both appear to be at greater risk for the development of pouchitis after IAPT.