New developments in the evaluation of gastroduodenal motility with special reference to duodenogastric reflux and its clinical significance.

New techniques in the study of gut motility must aim to improve our understanding of the flow of luminal contents, since this is the ultimate function of such motility. This paper reviews some areas of gastroduodenal motility relevant to our understanding of duodenogastric reflux. Antroduodenal motility has been studied in the past both manometrically and radiologically, but the function of the pylorus remains in doubt. Observations made using a new impedance technique at endoscopy on the timing of pyloric closure during antroduodenal motor activity suggest that the pylorus, in addition to being a functional appendage of the terminal antrum, can contract independently and in association with isolated duodenal contractions to prevent reflux. Retroperistaltic duodenal contractions, however, may not close the pylorus in time to prevent reflux, and duodenal activity rather than the pylorus may be the key to duodenogastric reflux. Studies using invasive techniques have implicated reflux in the aetiology of some gastric ulcers and gallstone dyspepsia. Non-invasive studies on reflux with the HIDA radionuclide scan have confirmed that reflux is minimal in normal subjects, more common in gallstone dyspepsia, and related to gallbladder function.