<prompt> POEM is used for:Achalasia cardiaCancer esophagusDiffuse esophageal spasmNutcracker esophagus  <response>: Per Oral Endoscopic Myotomy POEM POEM is the application of esophageal myotomy to the concept of NOTESby submucosal tunneling method . Used for treatment of achalasia Involves creation of long esophageal myotomy using flexible endoscope NOTES - Natural Orifice Transluminal Endoscopic Surgery 