Intestinal motility after massive small bowel resection in conscious canines: comparison of acute and chronic phases

To evaluate intestinal function after 80% massive distal small bowel resection (MSBR), we continuously monitored interdigestive and postprandial bowel motility using bipolar electrodes and/or contractile strain gauge force transducers in conscious beagle dogs before and at 2-4 weeks (acute postoperative phase; acute phase) and 8-13 months (chronic postoperative phase; chronic phase) after the surgery. Fasting duodenal migrating myoelectric (or motor) complexes (MMC) occurred at longer intervals in the acute phase after 80% MSBR than in control beagles. Intervals between duodenal MMC in the chronic phase were similar to those found in control beagles. MMC arising from the duodenum were often interrupted before the jejunum above the anastomosis in the acute phase, and a slight recovery of propagation frequency to the jejunum above the anastomosis was observed in the chronic phase. However, duodenal MMC did not migrate smoothly to the terminal ileum in both groups. In the acute phase, the velocity of duodenal MMC propagation was slowed in every intestinal segment, including the duodenum and the jejunum above the anastomosis, and had not recovered even long after the operation. The duration of the postprandial period without duodenal MMC was prolonged significantly in the acute phase postoperatively. Although it shortened in the chronic phase, it still remained significantly longer than in controls. These findings suggest that changes in gut motility after MSBR tend to compensate for the shorter intestine and maintain small bowel absorption early postoperatively. However, these compensatory changes decrease over the long term, and their adaptive contributions to increased intestinal absorption may decrease as well.