OBJECTIVE ASSESSMENT OF GASTROESOPHAGEAL REFLUX AFTER SHORT ESOPHAGOMYOTOMY FOR ACHALASIA WITH THE USE OF MANOMETRY AND PH MONITORING

The role of an antireflux procedure as an adjunct to esophagomyotomy f or achalasia remains a subject of controversy. Little objective docume ntation exists of this operation's effect on sphincteric competence an d the degree of postoperative gastroesophageal reflux. This report of esophageal manometry and 24-hour pH monitoring on 14 patients with eso phageal achalasia whom we had previously treated by a short esophagomy otomy without an antireflux procedure provides such documentation. Eso phagomyotomy reduced lower esophageal sphincter pressure by 12% to 71% (mean 41%) from a preoperative mean of 26.7 mm Hg to a postoperative mean of 14.6 mm Hg. The number of postoperative episodes of acid reflu x per patient in 24 hours was fewer than 29 (normal <49) in 13 patient s, with a median of 12 episodes for the entire group. Esophageal acid exposure, measured as percentage of total time with pH less than 4.0 ( normal < 4.5%), was below 4.5% in 10 patients, six of whom had values less than 1%. Among the four patients with values greater than 4.5%, o nly one had a temporal correlation of symptoms with an episode of acid reflux. Multivariate analysis showed that esophageal acid exposure ti me correlated only with the level of residual lower esophageal sphinct er pressure during the relaxation phase of deglutition. A pressure les s than 8 mm Hg was predictive of normal acid contact time (p < 0.001). Mean lower esophageal sphincter pressure, percent reduction in lower esophageal sphincter amplitude, postoperative vector volume, and lengt h of the lower esophageal sphincter did not significantly correlate wi th amount of esophageal acid exposure. We conclude that a short esopha gomyotomy without an antireflux procedure results in a competent lower esophageal sphincter in most patients. Increased esophageal acid expo sure, when it occurs, is due to slow clearance of esophageal acid from relatively few reflux episodes and is more likely to occur when there is a high residual pressure during deglutition after myotomy. These f indings suggest that the addition of an antireflux procedure to a shor t esophagomyotomy would not be expected to improve clinical results.