3-DIMENSIONAL PRESSURE IMAGE AND MUSCULAR STRUCTURE OF THE HUMAN LOWER ESOPHAGEAL SPHINCTER

Background. The structural equivalent to the manometric high pressure zone separating the stomach from the esophagus is still a matter of di spute. We compared the three-dimensional (3D) manometric measure image with muscular thickness and architecture at the human gastroesophagea l junction. Methods. Three-dimensional manometric images were obtained in 25 volunteers by using a stepwise pullback technique of a catheter with eight radially oriented pressure transducers. Muscle thickness w as measured in four radial directions at 10 levels between the midesop hagus and stomach in 37 specimens obtained from organ donors. Muscular architecture was assessed in specimens from 10 organ donors and 12 hu man cadavers and was related to muscle thickness. Results. Manometric 30 images of the lower esophageal high pressure zone showed a marked r adial and longitudinal asymmetry. Radial pressures peaked at the respi ratory inversion point and were highest toward the left posterior dire ction. Anatomic evaluation showed an asymmetric thickening of the musc ular layer at the gastroesophageal junction that mirrored the manometr ic image. Muscle thickness was highest toward the greater curvature si de corresponding to the gastric ''sling'' fibers and reward the lesser curvature corresponding to the semicircular ''clasp'' fibers. Conclus ions. The human lower esophageal sphincter is not a muscular ring. Rat her, the perfect march between the manometric pressures and the arrang ement of muscular structures at the gastroesophageal junction indicate s that the gastric sling fibers and the semicircular clasps are the an atomic correlate of the manometric lower esophageal sphincter in human beings.