Circular myotomy and esophageal length and safe esophageal anastomosis: an experimental study.

The indication for circular myotomy is often unclear at the time of esophageal atresia repair because the maximal permissible tension at the anastomosis and the precise effect of myotomy on esophageal length and anastomotic tension are not known. This study was undertaken to answer these questions. In piglets, 0 to 6.5-cm segments of thoracic esophagus were excised and approximation force was measured by dynamometers attached to traction sutures in each cut end of the esophagus prior to anastomosis. When approximation force was greater than 75 g. esophageal leaks occurred and increased fibrosis was noted at the anastomosis. Circular myotomy of the upper segment reduced the force necessary to approximate the ends of the esophagus after a 5- to 6-cm resection by about 50%, and double circular myotomy by as much as 75%. When the upper third of the esophagus of piglets and neonatal cadavers was stretched by the application of traction forces of 0 to 75 g. esophageal length increased by about 40%. Thereafter, length increase ws minimal. For any given traction force, each circular myotomy increased esophageal length by about 5 mm. These studies suggest that accurate measurement of approximation force would be useful at the time of esophageal atresia repair. On the basis of these data, circular myotomy(s) is indicated to elongate the esophagus and reduce anastomotic tension when a force greater than 75 g is needed to approximate the esophageal ends.