Heller myotomy is a surgical procedure[1] in which the muscles of the cardia (lower esophageal sphincter or LES) are cut, allowing food and liquids to pass to the stomach.
It is used to treat achalasia, a disorder in which the lower esophageal sphincter fails to relax properly, making it difficult for food and liquids to reach the stomach.
If the surgeon accidentally cuts through the innermost layer of the esophagus, the perforation may need to be closed with a stitch.
Nissen or complete fundoplication (wrapping the fundus all the way around the oesophagus) is generally not considered advisable because peristalsis is absent in achalasia patients.
An author search at Google Scholar can be used to find studies on a surgeon's past experience with achalasia patients.
However, some will eventually need pneumatic dilation, repeat myotomy (usually performed as an open procedure the second time around), or oesophagectomy.