Tip-fixing underwater endoscopic mucosal resection without submucosal injection for a laterally spreading colon polyp

In previous tip-in EMR studies, a spot-shaped mucosal incision was created at the oral normal mucosa with prior submucosal injections using the snare tip to fix the snare. However, submucosal injection was not required in our technique of tip-fixing underwater EMR. Essentially, intraluminal water serves as a heat sink which, when combined with a relatively thicker wall resulting from the relaxation of mucosal tension by removing intraluminal air, may protect against thermal injury of the deeper colonic wall even while making a precut with the snare tip. However, excessive snare exposure, overapplication of cautery, or deep snare driving could cause perforation, especially in thin-walled areas such as the right-sided colon or small intestine.