Underwater endoscopic colorectal polyp resection: Feasibility in everyday clinical practice.

Background: Endoscopic mucosal resection is well-established for resecting flat or sessile benign colon polyps. The novel underwater endoscopic mucosal resection eschews submucosal injection prior to endoscopic mucosal resection. Reports about underwater endoscopic mucosal resection were limited to small series of single and/or tertiary-care referral centers, with single or supervised operators.

Objective: The purpose of this study was to determine feasibility and efficacy of underwater resection of polyps of any morphology (underwater polypectomy, here includes underwater endoscopic mucosal resection) in routine clinical practice.

Methods: This study involved a comparison of colonoscopy records of two community hospitals (January 2015-December 2016) for underwater polypectomy ( = 195) and gas insufflation polypectomy ( = 186).

Results: Comparable demographics, procedural data, overall distribution, morphology and size of resected lesions, number of en bloc and R0 resections (any polyp morphology and size); exception: overall, underwater polypectomy pedunculated polyps were significantly larger than those in the gas insufflation polypectomy group,  = 0.030. Underwater polypectomy (median, min) resection time was significantly shorter than gas insufflation polypectomy: sessile and flat polyps 6-9 mm, 0.8 vs 2.7 ( = 0.040); 10-19 mm, 2.0 vs 3.3 ( = 0.025), respectively; pedunculated polyps 6-19 mm, 0.8 vs 3.3 ( < 0.001). Underwater polypectomy resection of pedunculated polyps 6-19 mm showed significantly less immediate bleeding: 11.1% vs 1.5%, respectively ( = 0.031).

Conclusions: Underwater polypectomy can be efficaciously used in routine clinical practice for the complete resection of colon polyps, with several advantages over gas insufflation polypectomy.