Colorectal Gel Immersion Endoscopic Submucosal Dissection Using the Tunneling Method

Colorectal endoscopic submucosal dissection (ESD) is now widely used for the treatment of colorectal tumors using several strategies. The effectiveness of the pocket-creation method combined with saline immersion has been reported with an improved endoscopic visual field and submucosal approach due to the buoyancy of the lesion and reduced the amount of submucosal injection. Its disadvantages include a poor visual field during bleeding and dissipation of coagulation ability with monopolar devices [1] [2]. However, gel immersion ESD has been reported to overcome these issues [3] [4] [5]. As the colorectum has a large lumen and may cause difficulties for gel immersion, it is assumed that a closed lumen such as a pocket or tunnel would facilitate gel immersion; therefore, the strategy of performing gel immersion ESD in combination with the tunneling method was devised.