A novel traction method using an endoclip attached to a nylon string during colonic endoscopic submucosal dissection.

Colorectal endoscopic submucosal dissection (ESD) is considered to be a difficult procedure that has a high risk of adverse events [1]. Endoscopic procedures should be performed under direct visualization, but it is often difficult to maintain appropriate visualization during submucosal dissection. A traction method using an endoclip attached to a string was developed in order to maintain good visualization of the submucosal layer during esophageal and gastric ESD [2,3]. However, this method was not applicable to colonic ESD because the colonoscope required reinsertion in order to mount the endoclip.We designed a novel traction method that did not require reinsertion of the colonoscope. A total of 15 patients underwent colonic ESD using this novel traction method at our endoscopy unit. First, a nylon string was inserted into the accessory channel of a colonoscope by grasping the end of the string with hemostatic forceps (FD410LR; Olympus, Tokyo, Japan), and pulling the string back up through the channel of the colonoscope. Next, the ends of the string were tied together outside of the colonoscope (●" Fig.1). The colonoscope was then inserted (●" Fig.2), and amucosal incision was performed. The nylon string was then cut externallyat thehand control end of the colonoscope, and the accessory channel end of the string was tied to the teeth of an endoclip (HX-610-090; Olympus) (●" Fig.3,●" Video1), which was attached to an applicator. Care was taken to not fully open the endoclip. The clip was then retracted into the applicator, and the applicator was inserted into the accessory channel. The endoclip grasped the anal side of the specimen (●" Fig.4a,b), and the nylon string was pulled gently (●" Fig.4c, ●" Video 1). Finally, the submucosal layer was dissected easily under direct visualization. All tumors were resected en bloc without adverse events. This traction method using an endoclip and nylon string, without the need for colonoscope reinsertion, is a new and feasible colonic ESD technique. This method may improve the ease and safety of colonic ESD.