Propagation of small bowel migrating motor complex activity fronts varies with anastomosis type

Abstract

Fasting small intestine motility (migrating motor complex or MMC) occurs in humans and dogs in four phases. Activity fronts during phase III consist of high amplitude contractions propagating aborally and are interrupted by transection of the small intestine. To study the effect of anastomosis type on MMC propagation six dogs underwent resection of a 15-cm segment of bowel 45 cm distal to the ligament of Treitz and single layer hand sewn end-to-end (EE) anastomosis. Single layer end-to-side (ES) or side-to-side (SS) anastomoses were hand sewn 15 cm distal to the transection in six other dogs. Eight force transducer strain gauges were placed at 10-cm intervals about each anastomosis. At least 7 days after operation, small bowel contractions were recorded in fasted animals, and recordings were visually inspected. Only 1 of 36 activity fronts propagated across the end-to-end anastomosis within 45 days of surgery. However, after 60 days 25 of 39 phase III activity fronts propagated. There was no propagation of MMC activity across the ES anastomosis and only 10% of activity fronts propagated across the SS anastomosis. We conclude phase III MMC activity front propagation is interrupted by small bowel transection. Propagation regenerates after EE anastomosis, but not after ES or after SS anastomoses, even after prolonged healing.