Postoperative adaptation of the small intestine after total colectomy and J-pouch-anal anastomosis

Abstract

Twelve patients who underwent total colectomy and J-pouch-anal anastomosis were followed up to 3 years after surgery to evaluate the functional and morphologic changes of the small-bowel reservoir. Intestinal absorption was impaired for lactose in 18 percent, for D-xylose in 27 percent, and for 75SeHCAT in 83 percent. Morphologic changes in ileal-pouch specimens consisted of a marked flattening of the villi and augmentation in crypt number and length. The number of Paneth's cells was increased compared with normal ileum. Parameters, indicating neorectal function such as stool frequency, pouch volume, and intestinal transit, improved in time during the postoperative course. Because of impaired small-bowel function, which is not restricted to the pouch reservoir, the ileum acquires progressive colonic capacities in accordance with its morphologic transformation to a colonic type mucosa. None of our patients developed clinical malabsorption requiring regular therapeutic substitution beyond a well-balanced diet due to these morphologic and functional changes and postoperative acceptance was good or excellent in all but one case.

Clinical and Physiological Aspects of Ileal Pouch-Anal Anastomosis

“…Retention of 75Se-taurohomocholate (SeHCAT) is decreased in these patients compared to non-operated colitis patients (75) or healthy controls (76,77). Postprandial conjugated bile acid levels increase to a lower extent in ileal pouch patients compared to healthy subjects (78).…”

“…Impaired intestinal absorption of D-xylose and low serum iron levels have been reported in ileal pouch patients. Nevertheless, clinical signs of malnutrition or malabsorption are rare in these patients (77). Low vitamin B12 levels and decreased Schilling tests have been found in patients with ileal pouch-anal anastomosis (57,74,82).…”

Restorative Proctocolectomy with Ileo-anal Reservoir, a Histopathological, Histochemical, and Electron Microscopic Study

“…Several studies have shown that the ileal pouch mucosa undergoes morphological changes and that most probably it reflects an adaptive response to the new luminal environment [4,5,6]. Transformation to a glandular morphology resembling colonic mucosa is common [7].…”

“…Histochemical changes in pouch mucin from sialo to sulphomucin are seen in pouches with villous atrophy [5]. These findings have led to the hypothesis that the pouch mucosa undergoes colonic metaplasia as an adaptive change but it may become vulnerable to immune damage or polyp formation, which eventually affects colonic and not ileal mucosa in the susceptible population [5,6]. Many studies until now state that the great majority of functioning ileal reservoirs develop chronic inflammation and villous abnormality regardless of the initial indication for pouch surgery [1,5] as also found in our study (Fig 1 refers).…”

Kinetics of Primary Bile Acids in Patients after Proctocolectomy and Ileal Pouch-Anal Anastomosis

“…Previous studies regarding the effect of proctocolectomy on bile acid metabolism were controversial. Several studies indicated that intestinal absorption of bile acids is impaired after proctocolectomy and IPAA [7,8,21,22,23]. It was assumed that impaired intestinal bile acid absorption was followed by formation of a more lithogenic bile and an increased incidence of cholelithiasis [5,6].…”