The ENKI-2 water-jet system versus Dual Knife for endoscopic submucosal dissection of colorectal lesions: a randomized comparative animal study

Background and study aims: The ENKI-2 water-jet system for endoscopic submucosal dissection (ESD) combines submucosal saline pressure injection with dissection. The aim of this study was to compare ENKI-2 with a standard device in terms of procedure time and perforation rate during colorectal ESD. Methods: In this randomized comparative study, 10 30-mm-diameter lesions were created in the colon and rectum of 10 healthy adult pigs. The ESD procedure time and perforation rates were recorded for the ENKI-2 system and a standard Dual Knife method. Each pig had half the lesions dissected by ENKI-2 and half dissected by Dual Knife. One experienced and one inexperienced endoscopist took part in the study. Results: A total of 95 lesions were dissected (47 by ENKI-2 and 48 by Dual Knife). The experienced endoscopist was able to excise comparably sized 30-mm lesions using both techniques. The dissection time was shorter for ENKI-2 (18.9 vs. 25.6 minutes; P=0.034) and the perforation rate was lower compared with the Dual Knife (one perforation [4%] vs. nine perforations [36%]; P=0.011). The inexperienced endoscopist performed significantly larger dissections using the ENKI-2 (934 405mm(2) vs. 673 +/- 312mm(2); P=0.021) despite pre-marking similarly sized artificial lesions. Multivariate analysis demonstrated that for all lesions the dissection time was significantly longer for lesions in the proximal colon (P=0.001) and the distal colon (P<0.0001) and shorter for the experienced operator (P<0.0001). ENKI-2 shortened the dissection time, but not significantly (P=0.093). Conclusions: In experienced hands, the ENKI-2 system shortens dissection time and reduces the perforation rate. This effect was not statistically significant for an inexperienced operator. Dissection was faster in the rectum than the colon.