Continuous low water pressure dissection technique minimizing air bubbles during underwater endoscopic submucosal dissection

Underwater endoscopic submucosal dissection (UESD) in saline offers several advantages [1] [2]. However, air bubbles generated during UESD can impair the visual field, particularly when they accumulate in the hood. To address this issue, outlets can be introduced on the side of the hood to facilitate air bubble removal [3] [4]. Nevertheless, air bubbles accumulate in the hood in cases where the lesion is located opposite to gravity, the tissue obstructs the air bubble outlet, or large air bubbles form. This repeatedly necessitates the use of the waterjet function of the endoscope to flush out the air bubbles. Under saline, air bubbles are generated by the evaporation of saline caused by the energization of the electrosurgical knife, which creates a "vapor pocket" that enables the knife to perform dissection [5]. Continuous high water pressure can make dissection difficult by hindering the formation of a sufficient vapor pocket, whereas continuous low water pressure helps maintain dissection power while minimizing and removing air bubbles. Therefore, we propose the continuous low water pressure dissection technique (CDT), which helps maintain the visual field during UESD ([Fig. 1]).