Adaptative Changes in the Small Intestine Following Bypass Operation for Obesity

Abstract

Roentgenographic follow-up studies were made in 7 patients before and at different intervals after jejuno-ileal bypass operation. Length measurements were made by a modified intubation technique, and intestinal transit time was estimated after a standardized contrast meal. Microscopical measurements of mucosal biopsies were done in 6 patients before, and 6 and 12 months after, the operation. A significant increase in the diameter of the functioning small intestine was found 4 months after the operation; in repeated investigations up to 18 months no further dilatation occurred. A gradual increase in intestinal length was demonstrated up to 18 months postoperatively. This compensatory growth appeared earlier and was most pronounced in the ileal part of the functioning intestine. Whereas the emptying time of the stomach and the intestine were unchanged, an increase in transit time was found 12 and 18 months after the operation. Measurements of mucosal biopsies showed an increase in mean villous height of the functioning jejunum of 14% and in the functioning ileum of 32%, 6 months after the operation. One year after operation the increase was 55% and 66% respectively. In the bypassed ileum atrophic changes were found with a decrease in villous height of approximately 18%. Probably the demonstrated hypertrophic changes in the functioning small intestine and the increase in transit time represent the basis for the functional adaptation that occurs in patients with a short gut.

Key words:

• By-pass operation
• intestinal adaptation
• intestinal morphology
• obesity