Effects of proximal duodenal transection and anastomosis on interdigestive sphincter of Oddi cyclic motility in conscious dogs.

Gallstones formed after gastrectomy are bilirubinate stones probably associated with biliary stasis and infection. Effects of proximal duodenal transection performed during gastrectomy on interdigestive sphincter of Oddi cyclic motility possibly relevant to this phenomenon were investigated in four conscious dogs. Although the cyclic change in sphincter motility was still in concert with the duodenal migrating motor complex after duodenal transection, the mean period was shortened (p < 0.02), and the frequency (p < 0.005) and amplitude (p < 0.001) of sphincter phasic waves during phase III were decreased. The cyclic variation of basal pressure disappeared, and the mean basal pressure throughout the cycle was significantly reduced (p < 0.003). Transient inhibition of sphincter and duodenal contractions normally seen during phase III disappeared. Duodenal transection reversed the response of the sphincter to cholecystokinin-octapeptide from inhibition to stimulation and from reduction of the basal pressure to elevation. These data suggest that duodenal transection produces significant changes in interdigestive sphincter of Oddi motility, possibly contributing to augmented duodenobiliary reflux and then lithogenesis. Myoneural continuity between the stomach and sphincter of Oddi at the proximal duodenum may play an important role in maintaining normal biliary dynamics.