The overtube in balloon-assisted endoscopic submucosal dissection is useful for improving maneuverability and as the drainage route in the continuous low-pressure saline-perfusion method.

Background and Aims: Continuous low-pressure saline perfusion in endoscopic submucosal dissection (ESD) combines drainage tubes with saline-immersion therapeutic endoscopy, eliminating bubbles from high-frequency devices and enhancing visualization. However, stable drainage in the proximal colon is challenging. We used a double-balloon overtube to improve maneuverability and drainage in a challenging case of a transverse colon tumor. Methods: A 60-year-old man with a 25-mm type 0-IIa transverse colon lesion underwent ESD using a double-balloon endoscope and overtube. Saline was continuously infused via a FlushKnife BTs (DK2620JB15S; Fujifilm, Tokyo, Japan) connected to a water jet pump, while suction through the overtube's injection route maintained stable drainage. Results: The procedure was completed safely with excellent visualization and no adverse events. Pathology confirmed tubular adenoma with negative margins. Conclusions: The balloon overtube offers 3 key advantages: (1) it improves maneuverability during proximal colonic ESD, (2) it facilitates cleaning of the working space by limiting the space by separating the colonic lumen with the balloon, and (3) it provides an effective drainage route during continuous low-pressure saline perfusion. This method is particularly useful for proximal colon lesions, especially in cases with poor maneuverability.