Gel immersion endoscopic mucosal resection for small gastric neoplastic lesions: A pilot study

Gastric endoscopic mucosal resection is challenging due to the slippery mucosa, abundant blood vessels, and the presence of mucus. We developed gel immersion endoscopy to secure the visual field, even in a blood-filled gastrointestinal lumen in 2016. Clear gel with appropriate viscosity, instead of water, can prevent rapid mixture with blood and facilitate identification of the culprit vessel. We further optimized the gel for endoscopic treatment, and the resultant product, Viscoclear (Otsuka Pharmaceutical Factory) was first released in Japan in 2020. The viscosity of this gel has been optimized to maximize endoscopic visibility without compromising the ease of its irrigation. The aim of this study is to clarify the effectiveness of gel immersion endoscopic mucosal resection for small-sized early gastric neoplasms. Seven lesions in seven patients were treated by gel immersion endoscopic mucosal resection. The size of all lesions was under 10 mm. The median procedure time was 4.5 min. Intraoperative bleeding occurred in four of seven lesions immediately after snare resection and was easily controlled by endoscopic hemostatic forceps during the gel immersion endoscopy. The R0 resection rate was 100%. In conclusion, gel immersion endoscopic mucosal resection may be a straightforward, rapid, and safe technique for resecting superficial gastric neoplasms <10 mm in diameter.