Underwater En Bloc Resection of Large Polyps

In underwater endoscopic mucosal resection (EMR), colorectal lateral spreading tumors (LSTs), or large sessile polyps, are removed after suction of luminal gas and filling of the colon with water but without submucosal injection.

In the current study, the group that developed this technique reported an attempt at en bloc resection of LSTs 2 to 4 cm in size in 50 patients. The median LST size was 30 mm (range, 20–40 mm).

Using a 33-mm stiff snare and pure cutting current, the success rate of en bloc resection was 55%. Delayed bleeding occurred in one patient and abdominal pain in another patient; no perforations occurred. Residual adenoma was found in 2 of 43 patients who underwent follow-up examinations.