INTRAOPERATIVE STUDY ON THE RELATIONSHIP BETWEEN THE LOWER ESOPHAGEAL SPHINCTER PRESSURE AND THE MUSCULAR COMPONENTS OF THE GASTROESOPHAGEAL JUNCTION IN ACHALASIC PATIENTS

Objective. The lower esophageal sphincter (LES) resting tone originates from the tension of the muscular fibers of the gastro-esophageal (GE) junction. This study determined which of the muscular structures of the GE junction are actually responsible and to what degree for the LES resting tone in achalasic patients. Summary Background Data. Controversy still exists as to the length of myotomy on the esophageal and gastric sides of the GE junction. Experimental and clinical studies have supposed that the anatomical complex formed by the U and the sling fibers of the lesser curvature of the stomach can be part of the LES. Methods. The variations induced on the LES resting tone by the separate division of the esophageal and gastric muscular fibers of the GE junction were studied by means of intraoperative manometry in 32 patients who underwent myotomy for achalasia. Results. After surgical preparation of the GE junction, the mean pressure was 29.3 +/- 13 mmHg. After esophageal side myotomy, the mean LES pressure decreased to 13.6 +/- 7.9 mmHg (paired t test, p < 0.0005). The residual pressure was further reduced after gastric side myotomy (3.4 +/- 1.9 mmHg; paired t test, p < 0.0005). Conclusions. In achalasic patients, 45% of the LES resting tone is maintained by the gastric side anatomical component of the GE junction. The range of variability of the gastric component of the LES is wide. This information should be taken into account when performing extramucosal myotomy as therapy for esophageal achalasia.