Underwater clip closure method for mucosal defects after duodenal endoscopic submucosal dissection (with video).

Conventional clip closure of mucosal defects after duodenal endoscopic submucosal dissection decrease the incidence of delayed adverse events, but may result in incomplete closure depending on size or location. This study aimed to assess the effectiveness of the underwater clip closure method for complete duodenal defect closure without the difficulties associated with conventional closure methods. We investigated 19 patients with 20 lesions who underwent endoscopic submucosal dissection of the duodenum and subsequent mucosal defect closure in underwater conditions at our facility between February 2021 and January 2022. The success rate of the underwater clip closure method was defined as the complete endoscopic closure of the mucosal defect; a success rate of 100% was achieved. The median resected specimen size was 34.3 mm, the median procedure time for mucosal defect closure was 14 min, and the median number of clips used per patient was 12. No delayed adverse events were observed. The underwater clip closure method is a feasible option for complete closure of mucosal defects, regardless of the size or location of a duodenal endoscopic submucosal dissection.