Cause of increase in “lower esophageal sphincter” pressure after fundoplication

Abstract

Several clinical and experimental studies have demonstrated that the distal esophageal high pressure zone is restored to normal following fundoplication. The response of this region to abdominal compression also returns to normal. The mechanism underlying these effects usually is attributed, without direct evidence, to restoration of neurohumoral response of the “lower esophageal sphincter” following fundoplication. Not all workers accept such explanation, however, preferring to view postoperative functional improvement as a simple mechanical effect of the fundoplication. If fundoplication somehow results in restoration of intrinsic resting tone and responsiveness of the “lower esophageal sphincter,” then ablation of the lower esophageal sphincter should interdict the effect. On the other hand, if the result of fundoplication is a simple mechanical one exerted through changes in intra-abdominal or intragastric pressure, then postoperative responses in the esophageal high pressure zone might be directly proportional to changes in intragastric or intra-abdominal pressure, even after ablation of the lower esophageal sphincter. The objective of the experiments reported here was to determine the change, if any, in the manometric response of the distal esophagus to “lower esophageal sphincter” ablation by total distal esophageal myomectomy followed by fundoplication.