Automatic water irrigation synchronized with the electrosurgical unit: Bubble-free underwater endoscopic submucosal dissection

The water pressure method is a underwater ESD technique, which facilitates direct visualization of the submucosa using a water stream through the waterjet channel of an endoscope [1]. This method significantly improves endoscopic exposure in difficult conditions such as the initiation of the submucosal dissection, dissection in a narrow space, and dissection of fibrotic tissue, and has been reported as useful for technically challenging ESD [2] [3] [4]. However, there is a problem in that the heat generated by the activation of the electrosurgical device at the lesion site creates bubbles in the water that often obstruct endoscopic visualization. In addition, especially when a tapered hood attachment is used, those bubbles are often trapped inside the attachment and are difficult to remove.