Comparison of dissection speed during colorectal ESD between the novel Multiloop (M-loop) traction method and ESD methods without traction.

We previously reported on a novel traction method called Multiloop (M-loop) for faster colorectal endoscopic submucosal dissection (ESD). In this study, we retrospectively compared the difference in submucosal dissection time (SDT), and submucosal dissection speed (SDS) between groups of patients who were treated using traction with the M-loop method, and with non-traction methods of colorectal ESD. We reviewed and timed duration of colorectal ESD by the non-traction method from videos recorded between June 2016 and December 2017. From January 2018 onward, we used the M-loop method during all colorectal ESDs and timed it until August 2018. Outcomes of colorectal ESD with the M-loop method and non-traction methods were compared. The study involved two experts and eight non-experts and was carried out at a tertiary endoscopic center in Japan. The study included 50 patients who treated with the M-loop method and 115 patients treated with the non-traction method. Submucosal dissection time (SDT) was not significantly different (M-loop group, 42.1  ±  4.2 min, non-traction ESD group, 51.9 ± 3.3 min) (  = 0.098), but submucosal dissection speed (SDS) was significantly greater (M-loop group, 28.0 ± 2.9 mm  /min, non-traction ESD group, 19.9 ± 2.0 mm /min) (  = 0.0014) in the M-loop method group. Multivariate analysis showed that the M-loop method increased SDS by odds ratio of 1.46 (  = 0.001) when compared to the non-traction ESD method. A significant difference was also observed for SDT and SDS when the two methods were compared after propensity score matching (  = 0.001). No differences in unfavorable outcomes were observed. The M-loop method improved SDS compared to non-traction methods of ESD. The method is an effective tool to assist colorectal ESD.