Published online May 14, 2017. doi: 10.3748/wjg.v23.i18.3309
Peer-review started: January 5, 2017
First decision: January 19, 2017
Revised: February 1, 2017
Accepted: March 30, 2017
Article in press: March 30, 2017
Published online: May 14, 2017
Core tip: Achalasia is a progressive disease, as verified by manometric and radiographic findings. Thus, we speculated that this progressive process could be visualized by endoscopy. We have proposed the Ling classification for achalasia on the basis of the endoscopic morphological severity of the esophagus. This study supports the hypothesis that the Ling classification portrays the progressive process of achalasia. Preliminary evidence suggests that successful peroral endoscopic myotomy (POEM) has the ability to prevent endoscopic progression of achalasia. Moreover, this study suggests that the Ling classification may serve as a criterion for endoscopic assessment of achalasia and will be useful for long-term endoscopic follow-up of post-POEM achalasia.