It is preferable for the endoscopes to be equipped with a water-jet system to wash away blood or mucus from the area of interest. ESD is principally carried out by using a single-channel upper gastrointestinal endoscope with a water-jet system (GIF-Q260J; Olympus Medical Systems Co, Tokyo, Japan), because of ease of manipulation of a more narrow scope. In case of tumors located in the proximal colon which are not reachable by the upper endoscope, a slim colonoscope with a water-jet system (PCF-Q260JI; Olympus Medical Systems Co, Tokyo, Japan) is used.

Various types of knives have been developed by Japanese endoscopists, and improvements continue to be made. Since their mechanical and electrical properties are different in how they cut, each knife must be used to understand the specific characteristics of a particular device. ESD devices are classified into those with non-insulated and insulated tips (Fig. 4.2a, b). Both knives also have a variety of merits and drawbacks.

A variety of non–insulated tip-type knives exist, including the needle knife (KD-1L-1; Olympus Medical Systems, Tokyo, Japan), FlexKnife (KD-630L; Olympus Medical Systems, Tokyo, Japan), DualKnife (upper length KD-650L and colonoscope length KD-650Q; Olympus Medical Systems, Tokyo, Japan), HookKnife (upper length KD-620LR and colonoscope length KD-620QR; Olympus Medical Systems, Tokyo, Japan), FlushKnife (Fujifilm Corporation), Splashneedle (PENTAX Medical, HOYA Corporation), Jet B-knife (Zeon Medical), and TriangleTipKnife (TT knife) (KD-640 L; Olympus Medical Systems, Tokyo, Japan).

When using a non-insulated tip-type knife, it is important to visualize the submucosa directly and place the knife parallel to the muscularis propria in order to prevent a deep cut and perforation. It is possible to cut and dissect the submucosal layer in as much detail as desired using these devices, and they can be manipulated in every direction for resection. However, this dissection is time-consuming, and it is easy to make mistakes that can cause perforation. The needle knife is the oldest and simplest knife that sharply cuts the tissue at the tip of the knife. However, when applied in a perpendicular direction to the intestinal wall, the knife can easily penetrate the entire bowel wall resulting in perforation. The HookKnife has a right angle bend at the tip of the needle knife. The direction of the hook can be controlled via handle rotation, which helps in the important task of keeping the hook oriented in a parallel orientation with the bowel wall to prevent perforation. The FlexKnife has a soft, thick, and looped knife tip, which acts well to prevent perforation. Furthermore, the tip of the outer sheath is rolled over by 1 mm, which functions as a stopper to keep the depth of tissue incision constant.

Currently available insulated tip-type knives include the IT knife (KD-610L; Olympus Medical Systems, Tokyo, Japan), SAFEKnife (Fujifilm Corporation), ClutchCutter (Fujifilm Corporation), and Mucosectom (PENTAX Medical, HOYA Corporation). The devices can cut and dissect the submucosal layer of the lesion using not the tip but the “blade” portion of the knife. This makes the dissection faster, although maneuvering these knives is slightly difficult. The basic technique for using insulated tip types of devices involves the ability to pull or slide the device laterally from side to side. The IT knife has a ceramic ball at the tip of a needle knife, which insulates the tip, so that cutting is achieved not by the tip but by the blade of the needle. The best way to use it is to place the ceramic ball in the submucosal layer to hook the mucosa or the submucosal connective tissue and then pull back on the knife. This is the only way to cut smoothly using an IT knife, so the knife sometimes has to be applied blindly, which risks complications such as bleeding and perforation. Recently, a scissors-type device such as the ClutchCutter (Fujifilm Corporation) has been developed, which can grasp, cut, or coagulate the targeted tissue using electrosurgical current, and is currently in investigation to see if it ameliorates some of the risks of ESD.

The selection of electrosurgical knives depends on the operator’s preference and expertise. The endoscopist must master the basic techniques necessary to manipulate each knife, and it is important to first be skilled in the use of one knife. With time will come the ability to choose the appropriate knife for different maneuvers.

The electrosurgical unit we use is the ICC 200 (ERBE Elektromedizin, Tübingen, Germany), ESG-100 (Olympus Medical Systems, Tokyo, Japan), or VIO 300D (ERBE Elektromedizin, Tübingen, Germany) (Fig. 4.3). It is necessary to place the output electrical power on a lower setting than that used for the stomach because the colon wall is very thin, and there is a real danger of perforation.

A transparent soft attachment which fits the tip of an endoscope (D201-11804, Olympus Medical Systems, Tokyo, Japan) or small-caliber tip transparent (ST) hood (Fujifilm Corporation) is attached to the tip of the endoscope to provide a constant endoscopic view even in the submucosal space and to apply countertraction to the connective tissue for submucosal dissection. It is essential for maintaining good position of the endoscope and visualizing the dissection line for the safe performance of ESD.