THE EFFECT OF ANTIREFLUX OPERATIONS ON LOWER ESOPHAGEAL SPHINCTER TONE AND POSTPRANDIAL SYMPTOMS

To elucidate potential mechanism(s) behind the mode of action of antireflux operations, the basal tone of the lower oesophageal sphincter and the relaxation after water swallows were studied before and after either a total fundic wrap (n = 25), highly selective vagotomy combined with fundoplication (n = 38), or insertion of an Angelchik prosthesis (n = 9). The basal tone preoperatively was similar in the three study groups, as was the relaxation that ensued on water swallows (nadir pressure). The fundic wrap increased the basal pressure in the lower oesophageal region from 13.0 +/- 2.3 (SE) to 21.2 +/-2.4 mm Hg (p = 0.01), and insertion of the prosthesis around the sphincter had a similar effect (from 10.2 to 19.3 mm Hg). However, the combined vagotomy and fundic wrap procedure did not significantly change the basal pressure recordings (13.9 to 14.3 mm Hg). The mean nadir pressure after water swallows increased significantly postoperatively in all study groups. Patients with fundoplication and highly selective vagotomy relaxed their lower oesophageal sphincter less than patients with fundoplication only (p < 0.05). Similar results were obtained in patients who had an Angelchik insertion, although this did not reach statistical significance.These results suggest that the fundic wrap functions in part as a mechanical external compression and that the vagus nerve contributes to the ability of the postoperative high-pressure zone to relax on swallowing. Regression and correlation analysis applied to the series of patients showed that the postoperative sphincter pressure characteristics were related to the final outcome as scored by the patients and was also related to the prevalence of persistent 'gas bloat' complaints.