Submucosal endoscopy: from ESD to POEM and beyond.

Peroral endoscopic myotomy (POEM) is an evolving minimally invasive endoscopic surgical procedure, with no skin incision, intended for long-term recovery from symptoms of esophageal achalasia. POEM was developed based on both the already established surgical principles of esophageal myotomy and the advanced techniques of endoscopic submucosal dissection. This article relates how POEM was developed, and its use in practice is reported and discussed. As an extension of the POEM technique, submucosal endoscopic tumor resection is introduced.