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Takamaru et al. Mini-invasive Surg 2022;6:15 https://dx.doi.org/10.20517/2574-1225.2021.120 Page 5 of 7

Table 1. Setting of generators for IT knife nano®
VIO 300D® Cut mode Coagulation mode
Effect 3 2
Maximum watt 100 W 50 W
VIO3® Cut Coagulation Coagulation Coagulation
Mode Dry CUT Precise SECT Forced COAG Swift COAG
Effect 4.7 6.0 6.0 5.0

Figure 5. Pocket creation method technique using IT knife nano. (A) An injected submucosal layer is recognized by attaching hood
devices. The insulated tip is put at the center of the submucosal layer (yellow arrow). (B, C) A little electric current makes a small
indentation. (D-F) After hooking the blade to the edge of the indentation, the IT knife nano can move to the right side slowly (blue
arrows) and resect the submucosal layer safely.

DISCUSSION
Various types of knife devices have been developed for colorectal endoscopic submucosal dissection.
Therefore, it is often difficult to choose the optimal type of device. These two points can be considered
when selecting a device: choosing the appropriate devices for the situation of colorectal ESD, and using a
familiar knife as the main device because colorectal ESD requires training.

When the IT knife nano is used for colorectal ESD, it is mainly used for submucosal dissection. Additional
needle-type devices are always required for first incisions. Therefore, performing ESD with a needle-type
device should only be considered when cost-effectiveness is emphasized. However, the IT knife nano is
considered as an option for difficult situations, such as lesions with severe fibrosis, or when rapid
submucosal dissection is required.

CONCLUSION
When choosing a knife with an emphasis on cost-effectiveness, a needle-type knife device seems to be the
most appropriate choice. However, the IT knife nano is stable even in situations where luminal movement
by breathing or heartbeats make it difficult to use needle-type devices. In addition, it is expected to be able
to complete the procedure without hemostatic forceps in colorectal ESD using the IT knife nano because it