Esophageal myotomy (e.g. Heller myotomy) is performed to relieve the unrelenting pressure of a lower esophageal sphincter than is incapable of relaxing (such as in achalasia). There are many different ways to perform the surgery, but most involve the creation of a new "pseudo" lower esophageal sphincter by wrapping the gastric fundus around the lower esophagus ("fundoplication").

Over time, the distal esophagus may "balloon" out proximally to the fundoplication, through the fundoplication (as above). This occurs in ~50% of patients. This finding is important to communicate to the referring physician, but may be asymptomatic and intervention may not be necessary.

The most important thing is to recognize this as an expected finding and to not assume it is an epiphrenic diverticulum or failure of the myotomy to relieve the achalasia.