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Kuwai et al. Mini-invasive Surg 2022;6:16 https://dx.doi.org/10.20517/2574-1225.2021.122 Page 5 of 8

Figure 3. The three basic steps of the ESD procedure using the SB Knife Jr: (A) grasping; (B) pulling; and (C) cutting. ESD: Endoscopic
submucosal dissection.

prevents bleeding.

Hemostasis procedure using the SB Knife Jr
The hemostasis procedure using the SB Knife Jr also follows the three steps described above, almost the
same as when using hemostatic forceps. Grasp a bleeding vessel precisely; pull the grasped vessel slightly (or
skip this step if far from the muscle layer); and apply the coagulation electric current for approximately 1 s
two or three times. Most cases can be managed with this procedure; however, if hemostasis is not achieved
after two or three attempts using the SB Knife Jr, the device can be changed to hemostatic forceps (e.g.,
Coagraspar; Olympus, Tokyo, Japan).

ADVANTAGES AND DISADVANTAGE OF THE SB KNIFE JR FOR COLORECTAL ESD
The technique of colorectal ESD using the SB Knife Jr is the same as that for the biopsy technique, which
does not require advanced skill and complex endoscopic manipulation. The rate of ESD self-completion for
trainees was reported as significantly better with the SB Knife Jr than with a needle-type knife .
[14]
Additionally, it is safe because the electric current can be applied just after confirming that the SB Knife Jr
did not grasp the muscle layer . As the SB Knife Jr also works as hemostasis forceps, there is no need to
[15]
change the device in the case of intraoperative bleeding during the procedure. This might be more cost-
effective because hemostasis forceps are not needed . These advantages of the SB Knife Jr make it useful
[16]
not only for trainees but also for experts in difficult situations.

A few reported disadvantages of the SB Knife Jr are prolonged procedure time of ESD as its use requires
multiple steps, as stated above [5,17] . In addition, the training of an assistant is needed to teach them how to
rotate the knife because effective knife rotation technique by assistants is essential in colorectal ESD when
using the SB Knife Jr . Another contributing factor for a prolonged procedure time may include the fact
[18]
that the SB Knife Jr lacks water-jet function, which is reportedly effective for reducing the procedure time of
colorectal ESD .
[19]

These disadvantages have been overcome with the development of the new SB Knife Jr 2. This new knife is
equipped with a rotation handle for one-to-one rotation of blades that facilitate easy manipulation by an
assistant. New coating materials to prevent unnecessary diathermy burn and a new blade design with a
[12]
protrusion might contribute to speedier resection . In addition, traction devices (such as an S-O clip)
significantly reduce the procedure time in colorectal ESD using scissor-type knives [15,20] .

CASE PRESENTATION OF COLORECTAL ESD USING SB KNIFE JR [Supplementary Video1]
A 61-year-old man was referred to our center with a 0-IIa (LST-NG) lesion of 40 mm in size at the
transverse colon [Figure 4A and B]. Magnifying endoscopic observation revealed a JNET 2 B and Vi (high-