title: Double-scope per oral endoscopic myotomy (POEM): a prospective randomized controlled trial.
abstract: BACKGROUND
  Since its introduction in 2010, per oral endoscopic myotomy (POEM) has offered an alternative to laparoscopic Heller myotomy for the treatment of achalasia. A gastric myotomy length of 3 cm has been recommended; however, it can be difficult to ensure that adequate submucosal dissection has been performed during the procedure. Commonly accepted endoscopic markers of the gastric side can be inaccurate, particularly in patients with prior endoscopic treatments, such as balloon dilation or Botox injection of the lower esophageal sphincter. We hypothesized that the use of a second endoscope would result in a more complete gastric myotomy.
  
  
  METHODS
  One hundred consecutive achalasia patients were randomized into single- and double-scope POEM groups. In the treatment group, a second endoscope was used to obtain a retroflexed view of the gastric cardia, while the dissecting scope transilluminated from the end of the submucosal tunnel. Prospectively collected data were analyzed, including myotomy lengths, procedure times, adverse events, and clinical outcomes.
  
  
  RESULTS
  POEM was completed with high rates of technical (98-100%) and clinical success (93-97%) in both groups, with a low rate of serious adverse events (2%). The second endoscope resulted in a 17 min increase in procedure time (94 vs. 77 min), myotomy extension in 34% of cases, and an increase in the average gastric myotomy length from 2.6 to 3.2 cm (p = 0.01).
  
  
  CONCLUSIONS
  A second endoscope is useful for ensuring a complete gastric myotomy during POEM. With minimal increase in procedure time and no increase in morbidity, it may be particularly useful in cases of sigmoid esophagus or otherwise altered anatomy that makes identification of the gastroesophageal junction difficult.
authors.affiliation: Digestive Disease Center, Showa University Koto Toyosu Hospital, Toyosu 5-1-38, Koto-ku, Tokyo, 135-8577, Japan. kevin.grimes@gmail.com.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Grimes
authors.affiliation: Digestive Disease Center, Showa University Koto Toyosu Hospital, Toyosu 5-1-38, Koto-ku, Tokyo, 135-8577, Japan.
authors.forename: Haruhiro
authors.initials: H
authors.lastname: Inoue
authors.affiliation: Digestive Disease Center, Showa University Koto Toyosu Hospital, Toyosu 5-1-38, Koto-ku, Tokyo, 135-8577, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Onimaru
authors.affiliation: Digestive Disease Center, Showa University Koto Toyosu Hospital, Toyosu 5-1-38, Koto-ku, Tokyo, 135-8577, Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Ikeda
authors.affiliation: Faculty of Medicine, Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand.
authors.forename: Amarit
authors.initials: A
authors.lastname: Tansawet
authors.affiliation: Digestive Disease Center, Showa University Koto Toyosu Hospital, Toyosu 5-1-38, Koto-ku, Tokyo, 135-8577, Japan.
authors.forename: Robert
authors.initials: R
authors.lastname: Bechara
authors.affiliation: Department of Endoscopy, Kobe University Hospital, Kobe, Japan.
authors.forename: Shinwa
authors.initials: S
authors.lastname: Tanaka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D004210:Dissection / Q000379:methods*; D004867:Equipment Design; D004931:Esophageal Achalasia / Q000601:surgery*; D049630:Esophageal Sphincter, Lower / Q000601:surgery*; D020701:Esophagoscopes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009055:Mouth; D057605:Natural Orifice Endoscopic Surgery / Q000295:instrumentation*; D011446:Prospective Studies; D055815:Young Adult
keywords: Achalasia; GI endoscopy; Per oral endoscopic myotomy (POEM); Therapeutic endoscopy