Heller&;s myotomy is done for:

Achalasia is associated with loss of ganglion cells in the esophageal myenteric plexus. These impoant inhibitory neurons induce LES relaxation and coordinate proximal-to-distal peristaltic contraction of the esophagus Achalasia is an esophageal motor disorder characterized by increased lower esophageal sphincter (LES) pressure, diminished-to-absent peristalsis in the distal poion of the esophagus composed of smooth muscle, and lack of a coordinated LES relaxation in response to swallowing. Barium radiology may show &;bird&;s beak&; appearance Ref : Bailey and love surgery text book 27th ed