Per-oral endoscopic myotomy (POEM) for a sigmoid type of achalasia: short-term outcomes and changes in the esophageal angle

Background Per-oral endoscopic myotomy (POEM) is an endoscopic procedure whereby the esophageal muscle is incised in order to lower the lower esophageal sphincter (LES) pressure. Since the time it was first performed in 2008 and subsequently reported on in 2010 by Inoue et al., POEM has been shown to be safe and effective for straight type of achalasia. On the other hand, the efficacy of POEM had been controversial for patients with achalasia of the sigmoid type, in which a high LES pressure is accompanied by morphological changes, including dilation, acute angulation, and rotation. The aim of this study is to evaluate the safety and efficacy of POEM in patients with sigmoid type of achalasia.