Value of histopathology for predicting the post-operative complications of ileo-anal anastomosis (J-pouch) procedure in children with refractory ulcerative colitis.

The J-pouch is a surgical procedure offered to children with refractory ulcerative colitis (UC) who have undergone subtotal colectomy to reconstruct a reservoir function with ileo-anal anastomosis. Unfortunately, post-operative complications may occur and can compromise the pouch function. We assessed rectal histopathology to determine whether severity of inflammation in the rectum prior to the creation of the J-Pouch was associated with post-operative complications. We retrospectively reviewed the histopathology of all J-pouch procedure specimens from paediatric patients during the period 2000-2013 using an objective grading system that assesses the chronicity and activity of the UC disease. We analysed the parameters for association with the post-operative complications. A classification tree algorithm was generated to predict the risk of complication based on histopathological parameters. A total of 28 paediatric patients were identified, among whom 10 developed post-operative complications (35%). The activity score at the recto-anal margin was higher among the patients with post-operative complications (mean 7.3±3.1 versus 4.8±3.1; p=0.04). The involvement of more than 5% colonic crypts with epithelial neutrophilic infiltration at the recto-anal margin was found to be an independent parameter that would stratify the patients into low-risk or high-risk group for developing complications (17% versus 64%; p=0.04). An association between UC disease activity at the recto-anal margin and post-operative J-pouch complications was determined. Potentially, this association suggests that a histopathological assessment of the recto-anal transitional zone may have value in guiding the surgeon on the risk of post-operative complications.