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. Methods: Between May 2015 and December 2017, 16 patients with a sigmoid type of achalasia underwent POEM in our institute. The POEM procedure was the same as that for the straight type of achalasia. The double-scope technique was used to check the distal end of the submucosal tunnel from the gastric side. The primary endpoint was improvement of Eckardt score at 2 months after POEM. The secondary endpoints comprised operating time, change in the esophageal angulation, and adverse events. Results: All patients underwent POEM without severe adverse events. The respective parameters before and after POEM significantly differed in terms of mean (SD) Eckardt score [4.9 (2.0) vs. 0.4 (0.6), p < 0.01], LES pressure [19.4 (10.2) vs. 9.2 (6.4), p < 0.01], and integrated relaxation pressure [17.6 (9.2) vs. 7.9 (5.5), p < 0.01]. The average operation time was 94.7 ± 31.4 min. The average esophageal angulation was 88.4° ± 23.1° before POEM and 109.5° ± 16.7° after POEM (p < 0.01). Four patients had postoperative complications that were treated conservatively. Conclusions: POEM can improve both LES pressure and esophageal angulation in patients with sigmoid achalasia. Graphic abstract: [Figure not available: see fulltext.]