Usefulness of gel immersion endoscopy for endoscopic resection in stomachs with residue.

Background and Aims: EMR and endoscopic submucosal dissection are widely used for treating intramucosal gastric neoplasms. However, securing a clear visual field in a stomach with residue is challenging. In this article, we present 2 cases in which tumors were endoscopically resected by securing the visual field using the gel immersion method in remnant stomachs after proximal gastrectomy with residue. Methods: The gel immersion method is a technique in which a transparent, viscous gel is injected into the lumen to secure the visual field. The viscous gel displaces blood and residue, allowing for a clear view. Therefore, we could perform efficient endoscopic procedures calmly. We also used the dedicated valve to add the gel while we inserted devices through its accessory channel. Results: In both cases, the gel immersion method successfully displaced food residue, providing a clear visual field and enabling precise mucosal incision and resection. In the first case, we achieved en bloc resection in a 71-year-old man with a 5-mm adenoma by using gel immersion EMR. In the second case, a 74-year-old man with a 12-mm intramucosal adenocarcinoma underwent gel immersion endoscopic submucosal dissection, which facilitated an accurate incision line and effective coagulation. Both patients had negative resection margins, and no adverse events were observed. Conclusions: The gel immersion method effectively improved visualization in a stomach with residue, enhancing the safety and precision of endoscopic resection.