[Etiological studies of manometric asymmetry in the lower esophageal sphincter (LES)]

In order to study the reason for manometric asymmetry of LES, the manometric profile of LES was measured at 3 different points (at the same level) of 20 normal infants and children by using 5 kinds of 3-lumen tubes with different rigidities. The results were; (1) the pressure was highest at 8 degrees (posterolateral wall) in LES by using all of the 5 esophageal tubes (p less than 0.001), and the length was shortest at 8 degrees in LES with 4 esophageal tubes, except for one 8 Fr. silicone tube. With this tube, LES had no asymmetry in the length. (2) The lower the rigidity of the esophageal tube, the less the asymmetry of the LES. In exact terms, the average coefficient of variations of LES pressure and length were; (in order of rigidity) 28.9% and 24.2% with a 12 Fr. vinyl-chloride tube, 25.7% and 23.4% with a 10 Fr. vinyl-chloride tube, 27.2% and 23.6% with a 8 Fr. evatate tube, 24.5% and 22.0% with a 8 Fr. vinyl-chloride tube, and 12.0% and 7.0% with a 8 Fr. silicone tube respectively. The variation in asymmetry of LES pressure and length were smollest by using the latter tube with the lowest rigidity. Therefore, the results suggest that the asymmetrical profile of LES was caused mainly by the rigidity of the esophageal tube rather than by the anatomical specialty of the esophago-cardiac junction.