Device-assisted traction methods in colorectal endoscopic submucosal dissection and options for difficult cases.

Endoscopic submucosal dissection (ESD) procedure has a longer procedure time and higher perforation rate than endoscopic mucosal resection owing to technical complications, including a poor field of vision and inadequate tension for the submucosal dissection plane. Various traction devices were developed to secure the visual field and provide adequate tension for the dissection plane. Two randomized controlled trials demonstrated that traction devices reduce colorectal ESD procedure time compared with conventional ESD (C-ESD), but they had limitations, including a single-center fashion. The CONNECT-C trial was the first multicenter randomized controlled trial comparing the C-ESD and traction device-assisted ESD (T-ESD) for colorectal tumors. In the T-ESD, one of the device-assisted traction methods (S-O clip, clip-with-line, and clip pulley) was chosen according to the operator's discretion. The median ESD procedure time (primary endpoint) was not significantly different between C-ESD and T-ESD. For lesions ≥ 30 mm in diameter or in cases treated by nonexpert operators, the median ESD procedure time tended to be shorter in T-ESD than in C-ESD. Although T-ESD did not reduce ESD procedure time, the CONNECT-C trial results suggest that T-ESD is effective for larger lesions and nonexpert operators in colorectal ESD. Compared with esophageal and gastric ESD, colorectal ESD has some difficulties, including poor endoscope maneuverability, which may be associated with prolonged ESD procedure time. T-ESD may not effectively improve these issues, but a balloon-assisted endoscope and underwater ESD may be promising options and these methods can be combined with T-ESD.