Randomized Clinical Trial Comparing Short Versus Long Oesophageal Myotomy in POEM for Achalasia Cardia.

General anesthesia will be administered and an esophagogastroduodenoscopy will be performed. Mucosal incision proximal to the gastroesophageal junction (GEJ) will be identified depending on short or long myotomy. A 1.5- to 2-cm mucosal incision will be performed after raising a submucosal wheal. The endoscope will be inserted to create a submucosal tunnel with a combination of blunt dissection, carbon dioxide insufflation, hydro dissection and careful electrocautery. The tunnel will be extended past the GEJ, 3 cm onto the gastric cardia. after myotomy, the mucosal incision will then be closed using standard endoscopic clips.