SB Knife Jr: characteristics and tips on how to use

Widespread adoption of colorectal endoscopic submucosal dissection (ESD) in clinical practice is lagging despite the peer evidence that it permits en bloc resection of large lesions that can be curative and facilitate pathological staging, thereby improving management. Limited adoption of colorectal ESD is likely due to technical challenges and a steep learning curve. Most conventional ESD devices are used without fixing the target, making them difficult to maneuver and thus creating a potential risk of perforation. Comparatively, a scissor-type knife, such as the SB Knife Jr, enables grasping of the target tissue, facilitating controlled dissection of tissue being held between the blades. This potentially prevents unexpected muscular layer injury. Colorectal ESD with the SB Knife Jr does not require complex endoscopic maneuvering or advanced skills for safe ESD. Since the incision and dissection procedure using the SB Knife Jr is different from that of conventional ESD knives, familiarization with its features is vital. In this review, we focus on the use of the SB Knife Jr for colorectal ESD. The basic colorectal ESD procedure using the SB Knife Jr consists of grasping, pulling, and cutting. By repeating these steps, circumferential incision, submucosal dissection, and hemostasis can be performed with a single device. For incision and dissection, a circumferential mucosal incision is performed similar to “cutting paper”. Submucosal dissection is performed with the image of “connecting the dots at the appropriate dissection depth”. The SB Knife Jr is useful as a secondary device in challenging ESD procedures, and surgeons should master its use.