Pyloric motility after pylorus-preserving gastrectomy with or without the pyloric branch of the vagus nerve

An attempt was made to examine gastropyloric motility after pylorus-preserving gastrectomy (PPG) and to determine the influence of the pyloric branch of the vagus nerve in the dog. Fifteen dogs were divided into three groups of five. PPG with preservation (PPPG) and resection of the pyloric branch of the vagus (RPPG) were performed, and controls were prepared. Interdigestive and digestive gastropyloroduodenal motility was recorded after a 2-week recovery period using strain-gauge force transducers (SG). Radiopaque markers (ROMs) were used to assess gastric emptying. No significant differences were found between PPPG and RPPG in terms of gastropyloroduodenal motility during either the interdigestive or the postprandial state. During phase III of the interdigestive state, pyloric relaxation correlated with contraction of the gastric body after both PPPG and RPPG. During the first month it was accompanied by tonic and phasic pyloric contractions after feeding and delayed gastric emptying in two groups. By the end of the first month these pyloric contractions had diminished, and the rate of gastric emptying was similar to that of the controls. We concluded that it is not necessary to preserve the pyloric branch of the vagus for gastropyloroduodenal motility after PPG. Gastric stasis during the early postoperative period is due to tonic and phasic contractions of the pylorus.