C0456 - Submucosal Lift During Underwater Endoscopic Mucosal Resection Preserves the Benefits of Underwater Technique

James S. Love, MD¹, Gabriel Marrero-Rivera, MD², Alexander Pan, MD¹, Kirbylee Nelson, MD³, Brian Boulay, MD^1
1University of Illinois at Chicago, Chicago, IL; ²University of Pittsburgh, Pittsburgh, PA; ³Northwestern Memorial Hospital, Chicago, IL

Introduction: Conventional injection-assisted endoscopic mucosal resection (EMR) is a widely accepted method for removal of laterally-spreading non-pedunculated polyps ≥10mm. Underwater EMR (uEMR) is an emerging technique which may result in higher en bloc resection and lower adenoma recurrence. uEMR typically does not include submucosal injection for lifting the lesion which may contribute to its limited adoption among practitioners of EMR. In this study, we aim to determine the safety and efficacy of underwater EMR with lift (uEMR-L) for large polyp resection.

Methods: uEMR-L was performed at a single center by an expert endoscopist over a 3 year period. A pediatric colonoscope with a transparent cap was advanced to the lesion and inspected with air insufflation and then with the lumen filled with sterile water. Intentionally limited submucosal injection was performed using a saline-based solution with methylene blue and dilute epinephrine. The lesion was then resected using a snare in en bloc or piecemeal fashion at the discretion of the endoscopist. Supplementary techniques were used as needed for completion of resection. Surveillance examination was planned in 6 months following uEMR-L. Data regarding patient age, sex, submucosal injection volume, procedural complications, and polyp size, morphology, histology, and recurrence was collected and included in our analysis.

Results: Between December 2017 and December 2020, 66 lesions were treated with uEMR-L in 51 patients. The mean size was 27.4 mm (range 15-60mm). The median submucosal injection volume was 7 ml (range 2-30ml, mean 9.2ml, SD 7.1). Complete resection was performed in 62/66 (94%) of the lesions. Of the incomplete resections, 2 were invasive adenocarcinoma, one extended into the appendiceal orifice, and one had extensive submucosal fibrosis. Ten of the lesions were removed en bloc, with mean size of 19.1 mm. Of the 62 lesions in which polypectomy was completed, 50 underwent surveillance examination a median of 200 days later. Only 2/50 polypectomy sites had residual polyp tissue which was resected endoscopically. One patient experienced delayed bleeding requiring admission. No other complications of bleeding, perforation, or unplanned admission were seen.

Discussion: uEMR-L is a safe and effective technique for endoscopic mucosal resection of large nonmalignant colon polyps. This specific technique may preserve the benefits of underwater resection and serve as an entry point for endoscopists without previous experience in underwater EMR.



Disclosures:


James S. Love, MD¹, Gabriel Marrero-Rivera, MD², Alexander Pan, MD¹, Kirbylee Nelson, MD³, Brian Boulay, MD¹. C0456 - Submucosal Lift During Underwater Endoscopic Mucosal Resection Preserves the Benefits of Underwater Technique, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.