[Surgical treatment of megaesophagus. Effect of myotomy and fundoplication on the lower esophageal sphincter].

Details about the structure of the lower esophageal sphincter and the function of fundoplication are yet unknown. New study is presented about electromanometric examination of the lower esophageal sphincter in 20 chagasic patients with megaesophagus operated on by cardiomyotomy complemented with His angle agudization (Group A-10 patients) or fundoplication (Group B-10 patients). On the 30th postoperative day, the patients, without dysphagia, were submitted to radiologic study, demonstrating valvuloplasty integrity (Group B), and electromanometric study of the esophagus. The comparison between the groups demonstrated: -myotomy does not modify the lower esophageal sphincter extension, but decrease its pressure, not to zero; -fundoplication does not increase the lower esophageal sphincter pressure after myotomy, under resting conditions. These conclusions suggest that: -lower esophageal sphincter is formed by muscular fibers interlacing, configuration that maintains residual regional pressure after myotomy; - in resting state, after myotomy, fundoplication exerts exclusively mechanical function, without increase of the lower esophageal sphincter pressure.