title: The effect of incremental distal gastric myotomy lengths on EGJ distensibility during POEM for achalasia.
abstract: BACKGROUND
  During peroral esophageal myotomy (POEM) for the treatment of achalasia, the optimal distal gastric myotomy length is unknown. In this study, we used a functional lumen imaging probe (FLIP) to intraoperatively measure the effect of variable distal myotomy lengths on esophagogastric junction (EGJ) distensibility.
  
  
  METHODS
  EGJ distensibility index (DI) (minimum cross-sectional area divided by intrabag pressure) was measured with FLIP after each operative step. Each patient's myotomy was performed in four increments from proximal to distal: (1) an esophageal myotomy (from 6 cm proximal to the EGJ to 1 cm proximal to it), (2) a myotomy ablating the lower esophageal sphincter (LES) complex (from 1 cm proximal to the EGJ to 1 cm distal to it), (3) an initial gastric extension (from 1 cm distal to the EGJ to 2 cm distal), and (4) a final gastric extension (from 2 cm distal to the EGJ to 3 cm distal).
  
  
  RESULTS
  Measurements were taken in 16 achalasia patients during POEM. POEM resulted in an overall increase in DI (pre 1.2 vs. post 7.2 mm(2)/mmHg, p < .001). Initial creation of the submucosal tunnel resulted in a threefold increase in DI (1.2 vs. 3.6 mm(2)/mmHg, p < .001). When the myotomy was then performed in a stepwise fashion from proximal to distal, the initial esophageal myotomy component had no effect on DI. Subsequent myotomy extension across the LES complex resulted in an increase in DI, as did the initial gastric myotomy extension (to 2 cm distal to the EGJ). The final gastric myotomy extension (to 3 cm distal) had no further effect.
  
  
  CONCLUSIONS
  During POEM, creation of the submucosal tunnel prior to myotomy resulted in a marked improvement in EGJ physiology. Myotomy extension across the LES complex and to 2 cm onto the gastric wall resulted in the normalization of EGJ distensibility, whereas subsequent extension to 3 cm distal to the EGJ did not increase compliance further.
authors.affiliation: Department of Surgery, Northwestern University Feinberg School of Medicine, 251 E. Huron Street, Galter 3-150, Chicago, IL, 60611, USA. e-teitelbaum@northwestern.edu.
authors.forename: Ezra N
authors.initials: EN
authors.lastname: Teitelbaum
authors.affiliation: Department of Surgery, Northwestern University Feinberg School of Medicine, 251 E. Huron Street, Galter 3-150, Chicago, IL, 60611, USA.
authors.forename: Joel M
authors.initials: JM
authors.lastname: Sternbach
authors.affiliation: Department of Surgery, Northwestern University Feinberg School of Medicine, 251 E. Huron Street, Galter 3-150, Chicago, IL, 60611, USA.
authors.forename: Rym
authors.initials: R
authors.lastname: El Khoury
authors.affiliation: Department of Surgery, Northwestern University Feinberg School of Medicine, 251 E. Huron Street, Galter 3-150, Chicago, IL, 60611, USA.
authors.forename: Nathaniel J
authors.initials: NJ
authors.lastname: Soper
authors.affiliation: Division of Gastroenterology and Hepatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Pandolfino
authors.affiliation: Division of Gastroenterology and Hepatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kahrilas
authors.affiliation: Division of Gastroenterology and Hepatology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Zhiyue
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Surgery, Northwestern University Feinberg School of Medicine, 251 E. Huron Street, Galter 3-150, Chicago, IL, 60611, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Hungness
mesh_terms: D000328:Adult; D000368:Aged; D004931:Esophageal Achalasia / Q000503:physiopathology / Q000601:surgery*; D049630:Esophageal Sphincter, Lower / Q000503:physiopathology / Q000601:surgery*; D004943:Esophagogastric Junction / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057605:Natural Orifice Endoscopic Surgery; D011312:Pressure; D011446:Prospective Studies
keywords: Achalasia; Esophageal physiology; Esophagogastric junction; Functional lumen imaging probe; Peroral endoscopic myotomy