Colorectal endoscopic submucosal dissection using a concealable robotic add-on device: A comparative in vivo feasibility study.

128 Background: Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe colonic endoscopic submucosal dissection (ESD). In this preclinical ex vivo and in vivo animal study, we developed a concealable robotic-assisted traction device and evaluated its performance in colorectal ESD. Methods: An experienced endoscopist performed ESD on an ex vivo porcine colon 18 times using our robot and 18 times using the conventional method. The outcome measures were procedure time, dissection speed, procedure-related adverse events, and blind dissection rate. We also conducted an in vivo feasibility study in live pigs. Robotic ESD was performed by experienced and novice endoscopist groups (n = 2, each). The outcomes included time to complete each ESD step, total procedure time, size of the dissected mucosa, rate of en bloc resection, and major adverse events. Results: Thirty-six colonic lesions were resected from ex vivo porcine colon samples. The total procedure time was significantly shorter in robotic ESD (RESD) than in conventional ESD (CESD) (20.1±4.1 vs. 34.3±8.3; P < 0.05). The submucosal dissection speed was significantly higher in the RESD group than in the CESD group (36.8±9.2 vs. 18.1±4.7; P < 0.05). The blind dissection rate was also significantly lower in the robotic group (12.8±3.4% vs. 35.1±3.9%; P < 0.05). In an in vivo feasibility study, the robot was attached to the colonoscope and successfully inserted into the proximal colon without damaging the colonic wall, and ESD was successfully performed. There was no significant difference in the submucosal dissection speed between the groups (P = 0.465). Conclusions: When the concealable robot assisted the colonic ESD procedure, the dissection speed and safety profile improved significantly. Thus, our robotic device can provide a simple, effective, and safe multidirectional traction during colonic ESD. When the robot was assisting in the ESD procedure, the dissection speed improved significantly, especially in the novice endoscopists.