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15 December 2018

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Int J Med Sci 2015; 12(6):450-457. doi:10.7150/ijms.11930

Research Paper

Comparison of Retroflexed and Forward Views for Colorectal Endoscopic Submucosal Dissection

Shintaro Fujihara, Hideki Kobara, Hirohito Mori, Yasuhiro Goda, Taiga Chiyo, Tae Matsunaga, Noriko Nishiyama, Maki Ayaki, Tatsuo Yachida, Tsutomu Masaki

Departments of Gastroenterology and Neurology, Faculty of Medicine, Kagawa University, Japan


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.

Keywords: endoscopic submucosal dissection, colorectal cancer, retroflexion, laterally spreading tumor, procedure time

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) License. See for full terms and conditions.
How to cite this article:
Fujihara S, Kobara H, Mori H, Goda Y, Chiyo T, Matsunaga T, Nishiyama N, Ayaki M, Yachida T, Masaki T. Comparison of Retroflexed and Forward Views for Colorectal Endoscopic Submucosal Dissection. Int J Med Sci 2015; 12(6):450-457. doi:10.7150/ijms.11930. Available from