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Page 4 of 13 Shichijo et al. Mini-invasive Surg 2022;6:19 https://dx.doi.org/10.20517/2574-1225.2021.121

Clip flap method
Yamamoto et al. [21-23] developed a clip-flap method for mucosal creation, which is key for successful ESD. An
endoclip is substituted for the mucosal flap until the flap is created completely. That is, the edge of the
exfoliated mucosa is clipped with an endoclip, the distal attachment is inserted under the endoclip, and
good visibility of the submucosal layer is obtained, leading to flap creation. It is particularly useful when
unexpected fibrosis is encountered, or when a vertical approach is undertaken.

Traction
ESD is performed by a single endoscope (i.e., by a single hand) while most surgeries performed by surgeons,
including laparoscopic surgery, are performed by two or more hands, taking advantage of traction. For
colorectal ESD, gravity is the simplest method for traction, and position change is relatively easy while
performing colorectal ESD, but not ESD for upper gastrointestinal lesions. In this section, we describe
various methods and devices for additional traction.

Clip with line
A traction method using an endoclip attached to a string was developed for maintaining good visualization
of the submucosal layer during upper gastrointestinal ESD [24,25] . However, this method was not applicable to
colonic ESD because the reinsertion of the colonoscope is required to mount the endoclip attached to a
string. We invented a novel traction method, called traction-assisted colorectal ESD, without reinsertion of
[26]
the colonoscope . By inserting a long string through the accessory channel of the colonoscope in advance,
we can use the clip-with-line method after mucosal incision without reinsertion of the colonoscope. We
demonstrated its efficacy (shorter procedure time and higher self-completion rate) in a randomized
[28]
manner and also succeeded in resecting the lesion involving a diverticulum .
[27]
Pulley method
The above-mentioned traction-assisted colorectal ESD is useful in most cases, but the direction of traction is
only toward the anal side, which is not always ideal. “Pulley” methods for upper gastrointestinal ESD have
[33]
[32]
been reported [29-31] , and we published a video case report and case series of “pulley” traction-assisted
colorectal ESD [Figure 2].
Clip with loop
Various traction methods using a loop connected to a clip, such as a clip with a ring , S-O clip [35-37] , and
[34]
loops-attached rubber band have been reported . The advantage of these methods is that traction is
[38]
obtained without reinsertion of the colonoscope. Furthermore, the pulley method can be used to alter the
direction of traction and tighten the traction force. After resection of the lesions, a cutting loop to separate
the resected lesions from the colonic wall is required.

Suturing
A large defect after colorectal ESD is associated with adverse events such as perforation and post-ESD
coagulation syndrome (PECS). In previous studies, complete closure of defects after colorectal ESD may be
effective in minimizing adverse events ; however, complete closure of large defects is often technically
[39]
difficult. Here, we highlight various methods of closure because ESD ulcers are sometimes large and simple
closure by clipping may be difficult.

Line-assisted complete closure
We developed a novel closure technique using a clip and line and named it line-assisted complete
closure [40,41] . An endoclip with a long nylon line attached is inserted through the accessory channel and
placed on the normal mucosa, just proximal to the ESD ulcer. Another endoclip without a line is anchored