The anti-reflux mechanism after cardiomyotomy.

Only 18 or 83 patients who had had a cardiomyotomy for achalasia could be induced to reflux barium. Mucosal herniation through the myotomy was shown in most by radiography. Perfusion manometry showed a higher pressure zone in the oesophagogastric junction region in 22 of 24 patients studied. This high pressure zone responded to an increment in abdominal pressure by a greater increment. The same response was seen in a patient with a small hiatal hernia and myotomy. We concluded that the persisting high pressure zone seen by perfusion manometry is likely to be caused by the hiatus, and that the hiatus rather than the sphincter is likely to be responsible for the incremental response of the high pressure zone to increased abdominal pressure. The anti-reflux mechanism after cardiomyotomy is more likely to be the hiatal mechanism than persisting sphincter fibres.