Longterm appraisal of the histological appearances of the ileal reservoir mucosa after restorative proctocolectomy for ulcerative colitis.

Between November 1976 and December 1985, 110 patients had restorative proctocolectomy for ulcerative colitis. The histological appearances in the reservoir mucosa were followed up in 60 of 109 survivors over 19-173 months (median 97). The median number of biopsy specimens taken per patient was six with a range of 3-13. These were examined by one pathologist (ICT) unaware of the clinical details using a scoring system previously described to assess the degree of chronic and acute inflammation. There was a significant correlation between the degree of severity of chronic and acute changes (r = 0.6192, p < 0.000001). There was no correlation between the severity of inflammation and the following variables: preoperative duration of disease, presence of cancer or dysplasia in the original operative specimen, extra-alimentary manifestations or the type of reservoir. A significant correlation between severe inflammation and male sex was found (p < 0.035). The 60 patients could be divided into three groups based on the severity and fluctuation of histological inflammation. In group A (n = 27, 45%) chronic changes were minor and acute inflammation was never seen. In group B (n = 25, 42%) chronic changes were more severe and there were transient episodes of acute inflammation. In group C (n = 8, 13%) severe chronic and severe acute inflammation were constantly present. Differentiation of the three groups had clearly occurred within six months from closure of the ileostomy. Patients in group C could be identified on histological criteria within weeks of closure of the ileostomy and were those exclusively at risk of developing chronic pouchitis. Chronic pouchitis never occurred in patients of groups A and B. No case of dysplasia was seen. Histological assessment of the reservoir mucosa with in a few months after closure of the ileostomy seems to define patients who will and who will not subsequently develop pouchitis.