A study was undertaken to assess the incidence of inflammation and dysplasia in retained mucosa after double-stapled ileoanal reservoir (IAR) for mucosal ulcerative colitis (MUC). Between September 1988 and February 1992, 56 patients with MUC underwent an IAR. Forty-five patients had a double-stapled IAR (DS-IAR), seven patients had a transanal pursestring stapled IAR (PS-IAR), and four patients had a PS-IAR with mucosectomy. Distal donuts obtained from the stapled IAR were submitted for pathologic review in 55 patients. Nine patients had only small bowel, connective tissue, and/or muscle noted on review. Mucosa was qualified as squamous epithelium (SE), transitional epithelium (TE), or columnar epithelium (CE). All samples were examined for evidence of inflammation and dysplasia. Four patients had SE only, one patient had TE, and 18 had CE. In addition, three patients had SE and CE, seven patients had SE and TE, two patients had CE and TE, and nine patients had all three types. The distance from the dentate line to the anastomosis ranged from 0 to 2.5 cm (mean, 1 cm). In 19 patients (35 percent), the distal donut revealed MUC. Of these 19 patients, six had persistent MUC (43 percent) at the time of subsequent biopsy. An additional four patients had MUC evident on follow-up biopsy but not on distal donuts; two of these four patients had no mucosa in their distal donuts. Only one of the patients with evidence of MUC on donuts and/or biopsy experienced any symptoms referable to active MUC (1.8 percent). None of the specimens examined had any evidence of dysplasia. In 31 patients, no MUC was present in the initial donuts or follow-up biopsies. Although the double-stapled technique appears safe, periodic monitoring is suggested.
