title: Comparison of Retroflexed and Forward Views for Colorectal Endoscopic Submucosal Dissection.
abstract: BACKGROUND
  The use of a retroflexed view exposes the entire tumor surface, which is obscured in the forward view, and contributes to complete tumor resection when combined with forward views. However, the efficacy and safety of using the retroflexed view for colorectal endoscopic submucosal dissection (ESD) are poorly understood.
  
  
  METHODS
  In this study, we assessed the efficacy and safety of the retroflexed view in colorectal ESD. From April 2009 to December 2013, 130 colorectal tumors were examined in 128 patients treated with ESD. A total of 119 patients with a mean tumor size of 27.2 mm were enrolled in the study, and these patients were assigned to undergo colorectal ESD with or without a retroflexed view.
  
  
  RESULTS
  The use of retroflexion was successful in 84.2% of patients. There were no perforations in the study and no complications related to the use of retroflexed views. The mean procedure time was 103.6 ± 55.8 min in the retroflexed group, as compared with 108.0 ± 66.5 min in the forward view group. The mean procedure time for resecting tumors >40 mm was significantly shorter in the retroflexed group relative to the forward group. Additionally, the mean dissection speed per unit area was significantly faster in the retroflexed group, as compared with the forward group.
  
  
  CONCLUSIONS
  Retroflexed views can be used to remove lesions >40 mm and shorten procedure times. Retroflexion may also contribute to an improved en bloc resection rate.
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Fujihara
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kobara
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Mori
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Goda
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Taiga
authors.initials: T
authors.lastname: Chiyo
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Tae
authors.initials: T
authors.lastname: Matsunaga
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Nishiyama
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Ayaki
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Yachida
authors.affiliation: Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Masaki
mesh_terms: D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome
keywords: colorectal cancer; endoscopic submucosal dissection; laterally spreading tumor; procedure time; retroflexion