This ASG video tip is brought to you by an educational grant from Braintree, a part of Cibela Pharmaceuticals, makers of SUTAB. We're watching an endoscopic mucosal resection of a lateral spreading lesion in the ascending colon. We've grabbed the hold of a piece of that lesion, opened the snare to release it, and now we're re-grasping the lesion and preparing for a transection. You can see off to the right the contrast stain submucosa from resection of a previous portion. Part of the lesion has not been removed yet. We're about to move this section off of the defect, and in the defect you can see an area with some depression and a couple of bands, white bands, along the top of the depression. The question is, what has happened during this EMR, if anything? The correct answer is type 3 muscle injury. There are five types of muscle injury that can occur during EMR according to Michael Burke's classification scheme. Type 3 is a type where the muscle is actually cut, and it's seen typically as parallel white bands that are designated here by the arrows. You have to recognize this and reinforce it, close it, basically, with clips or there is risk of a delayed perforation.

endoscopic mucosal resection

lateral spreading lesion

ascending colon

type 3 muscle injury

delayed perforation