title: Submucosal endoscopy: the new frontier of therapeutic endoscopy.
abstract: OBJECTIVE
  Peroral endoscopic myotomy (POEM) and submucosal tunneling and endoscopic resection (STER) have been recently described as minimally invasive therapies for achalasia and gastrointestinal subepithelial tumors originating from the muscularis propria, respectively. This review illustrates the latest developments in the field of submucosal endoscopy, focuses on POEM and sheds light on STER.
  
  
  RESULTS
  Multiple studies from the United States, Asia and Europe have shown that POEM is an effective and safe procedure for achalasia when performed by experienced operators with adequate clinical response in 80-90% of patients. Nonetheless, POEM requires a demanding skill set that involves both advanced endoscopic skills and knowledge of surgical anatomy. In addition, the endoscopist must have the capability to manage procedural complications. Similarly, STER appears to be an effective therapy for treatment of small and medium sized gastrointestinal tumors originating from the muscularis propria.
  
  
  CONCLUSIONS
  POEM and STER offer minimally invasive and effective treatment alternatives for patients with achalasia, spastic esophageal disorders and upper gastrointestinal tumors originating from the muscularis propria.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
authors.forename: Mouen A
authors.initials: MA
authors.lastname: Khashab
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Messallam
authors.forename: Mohamad
authors.initials: M
authors.lastname: El Zein
authors.forename: Vivek
authors.initials: V
authors.lastname: Kumbhari
mesh_terms: D004210:Dissection / Q000379:methods*; D016099:Endoscopy, Gastrointestinal / Q000379:methods*; D005767:Gastrointestinal Diseases / Q000601:surgery*; D006801:Humans; D007413:Intestinal Mucosa / Q000601:surgery*; D016896:Treatment Outcome