Intrachannel delivery of a drainage tube beyond the endoscope tip for continuous low-pressure saline perfusion during endoscopic submucosal dissection

We have previously reported the effectiveness of the continuous low-pressure saline perfusion (CLPSP) method in endoscopic submucosal dissection (ESD).[ 1​ ] [ ​2​ ] CLPSP is an effective method that achieves the two essential conditions for safe and efficient ESD: maintaining a consistently collapsed lumen and maximizing the benefits of saline immersion, maintaining a clear view by continuous perfusion. Regarding drainage techniques, we have reported the use of Foley catheters, alpha-loop-shaped tubes and the scope-wrapping method (Asclepius tube) in colorectal ESD [ 3​ ] [ 4​ ] [ ​5​ ], as well as clip fixation of the tube tip to the gastric mucosa for gastric ESD.[ 1​ ] However, clip fixation to the gastric mucosa can detach due to friction between the tube and the endoscope. Furthermore, these methods have limitations, such as insufficient aspiration of gas and fluid that accumulates beyond the endoscope. To address these limitations, we devised a simple technique: the drainage tube is secured to the scope with parafilm, the tip of the tube is bent to the desired length, inserted into the accessory channel and delivered into the lumen ([ Video 1 ]). Because the working channel diameter of a therapeutic endoscope is 3.2 mm, a tube size of ≤9 Fr is required ([ Fig. 1 ]). Insertion of an injection needle through the channel pushes out the tube, allowing the tip to be deployed and positioned distal to the lesion. Video 1 A simple and effective delivery beyond the endoscope tip for the continuous low-pressure saline perfusion (CLPSP)-ESD. Download Video Fig. 1 The drainage tube is secured to the scope with parafilm. The tip of the tube is bent to the desired length and inserted into the accessory channel. Because the working channel diameter of a therapeutic endoscope is 3.2 mm, a tube size of ≤9 Fr is required. In the duodenal ESD, because the tip of the tube is positioned distal to the lesion, it enables efficient recovery of saline flowing toward the anal side, thereby reducing the risk of saline overload ([ Fig. 2a ]). In esophageal ESD, adjusting the folded length of the tube enables the tip to reach the stomach, facilitating continuous drainage of both esophageal and gastric gas and fluid ([ Fig. 2b ]). This technique is also applicable to gastric and colorectal ESD. Fig. 2 Because the tip of the tube is positioned distal to the lesion, it enables efficient recovery of saline flowing toward the anal side. ( a ) Duodenal ESD setting. ( b ) Esophageal ESD setting. This method represents a very simple, effective, and cost-efficient drainage strategy for CLPSP-ESD. Endoscopy_UCTN_Code_TTT_1AQ_2AD_3AD Publication History Received: 06 June 2026 Accepted after revision: 19 July 2026 Article published online: 14 August 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/). Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany