The water pressure method is a underwater ESD technique, which facilitates direct
visualization of the submucosa using a water stream through the waterjet channel of
an endoscope [1]. This method significantly improves endoscopic exposure in difficult conditions
such as the initiation of the submucosal dissection, dissection in a narrow space,
and dissection of fibrotic tissue, and has been reported as useful for technically
challenging ESD [2]
[3]
[4]. However, there is a problem in that the heat generated by the activation of the
electrosurgical device at the lesion site creates bubbles in the water that often
obstruct endoscopic visualization. In addition, especially when a tapered hood attachment
is used, those bubbles are often trapped inside the attachment and are difficult to
remove.
To solve this drawback, we have developed a modified underwater ESD technique that
uses a water irrigation pump controlled synchronously with the activation from the
electrosurgical unit. An endoscopic water irrigation pump (EIP2; Erbe, Tübingen, Germany)
([Fig. 1]) is connected to the waterjet channel by a dedicated tube. This EIP2 pump also has
a wired connection to the VIO3 electrosurgical unit (Erbe), that enables simultaneous
activation of the pump and the VIO3 ([Fig. 2],[Fig. 3]). Water irrigation is done automatically when incision or coagulation currents are
activated, thereby removing any generated bubbles before they can be trapped in the
hood attachment and enabling a continuously clear view for ESD performance ([Fig. 4], [Video 1]). We use the EIP2 with an output power of 50%–60%, but we recommend adjusting the
power on a case-by case basis.
Fig. 1 Water irrigation pump (EIP2; Erbe, Tübingen, Germany).
Fig. 2 Preparation of the EIP2 water irrigation pump and setting of the VIO3 electrosurgical
unit.
Fig. 3 Schematic of the automatic and synchronized water irrigation system.
Fig. 4 Comparison of endoscopic image of bubbles inside the endoscopic tip attachment after
1 s of instrument activation. a Conventional underwater endoscopic submucosal dissection (underwater ESD) using the
water pressure method. b Using the automatic synchronized water irrigation system (bubble-free underwater
ESD).
Bubble-free underwater endoscopic submucosal dissection (underwater ESD) using an
automatic water irrigation system that synchronizes with an electrosurgical unit.Video
1
The bubbles generated during underwater ESD compromise endoscopic visibility, which
may lead to loss of procedural precision. Our new technique, named “bubble-free underwater
ESD,” can be a simple and practical solution.
Endoscopy_UCTN_Code_TTT_1AQ_2AD
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