"Underwater" endoscopic submucosal dissection: a novel method for resection in saline with a bipolar needle knife for...

Despite improvements in therapeutic strategy and instrumentation in colorectal endoscopic submucosal dissection (ESD), adverse events sometimes occur. Further advancements in available techniques are required to improve procedural success rates and safety. We developed a novel method for ESD in saline, referred to as "underwater" ESD (UESD). UESD involves using a bipolar needle knife and aims to enable complete resection while minimizing thermal damage to the muscle layer. In this study, we evaluated the safety and efficacy of this new technique.

This was a retrospective study using data from two referral centers and included 40 lesions diagnosed as colorectal epithelial neoplasia (> 20 mm in diameter or with severe fibrosis) and treated with UESD between December 2015 and March 2017. The main outcome measures were technical success rate, incidence of adverse events, and feasibility of histologic evaluation of the resected specimens.

All 40 lesions, including those with submucosal fibrosis, underwent successful en bloc resection using the UESD technique. No procedural adverse events including perforation, delayed bleeding, and electrocoagulation syndrome were observed, and all patients had an uneventful clinical course associated with UESD. In all cases, UESD provided a resected specimen adequate for histological evaluation, without unwarranted burn effect to the tissues.

Our UESD technique was safe and effective for complete resection of colorectal epithelial neoplasia.