[Endoscopic Treatment for Esophageal Achalasia:Per-oral Endoscopic Myotomy( POEM)].

Per-oral endoscopic myotomy( POEM) is an endoscopic treatment of achalasia. Since the world's first case was performed in Japan in 2008, over 15 years have passed. More than 3,200 cases have been performed at Showa University alone, and over 6,000 cases have been performed throughout Japan. The success rate in Japan exceeds 97%. Internationally, the efficacy of POEM has been demonstrated to be equal to or better than surgical treatment in randomized controlled trials( RCTs) with Heller-Dor surgery [The New England Journal of Medicine (NEJM) 2019]. Additionally, the superiority of POEM over balloon dilation therapy was proven in another RCT (NEJM 2011). Based on the results of these two RCTs, POEM has become the standard treatment for achalasia and the first choice of treatment. Furthermore, when compared to Heller-Dor surgery, POEM has the decisive advantage of easily extending the myotomy on the esophageal side without leaving any external scars. Especially for type Ⅲ in the Chicago classification, POEM is particularly the first choice. Technically, the double scope technique allows for a 2 cm myotomy on the gastric side, preventing both incomplete myotomy and post-POEM gastroesophageal reflux disease( GERD).