title: Why the Heller operation is preferred to dilatation in achalasia of the esophagus.
mesh_terms: D000293:Adolescent; D002299:Cardia / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D004106:Dilatation; D004931:Esophageal Achalasia / Q000601:surgery*; D004947:Esophagus / Q000601:surgery*; D006801:Humans; D007223:Infant; D008722:Methods