Endoscopic procedures, such as endoscopic mucosal resection (EMR) for large gastric
lesions, are performed blindly [1]
[2]. Precise snaring during EMR is important to carry en-block resection. However, this
can be difficult to achieve in practice because it is impossible to perform snaring
by complete observation. Although we can easily observe the proximal side of the lifting
lesion, it is hard to see the distal side after injection of saline solution into
the submucosa. Therefore, we developed a novel 1-channel camera-hood, which allows
an observation of the distal side of the lesion during snaring in EMR procedures.
Recently, we developed a novel one-third partial transparent hood that facilitates
endoscopic hemostatic procedures, while simultaneously allowing irrigation of the
bleeding site [3]. The one-third partial hood is easily placed on the tip of the endoscope, although
the hood has to be fitted to the right side of the endoscope (Figure [1]). The 1-channel camera-hood was fabricated by cutting the partial hood into a ‘U-shape’
in the cap portion of the hood, and then attaching a machined camera for dental use,
which consisted of charge coupled device (CCD) camera and four light-emitting diodes
(LED) (“Miharu-kun”; RF System Lab., Japan) through two tubes (Figure [2]). The length of the two tubes is variable, and one of these is an accessory channel.
Figure 1 The 1-channel camera-hood being placed at the tip of the endoscope.
Figure 2 Schema of the 1-channel camera-hood.
The EMR procedure using the 1-channel camera-hood was performed as follows (Figure
[3]). Marking dots were made on the circumference of the target tumor to outline the
margin. After injection of a saline solution into the submucosa, the tumor was separated
from surrounding normal mucosa by complete incision around the lesion using the insulated-tip
knife. The endoscope was then removed, and the 1-channel camera-hood was placed on
the tip and fixed with tape. A snare was passed through the accessory channel of the
hood, and a grasping forceps was passed through the accessory channel of the endoscope.
We made the grasping forceps catch hold of the snare. We strangulated the lesion by
precisely closing the snare, while allowing adequate observation by both CCD cameras
of the 1-channel camera-hood and the endoscope. Blend electrosurgical current was
used to resect the lesion.
Figure 3 Schematic representation of endoscopic mucosal resection using the 1-channel camera-hood.
Two specimens were resected in an animal model (pigs). The average diameter of the
resected specimen was 30 mm.
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