Recently, endoscopic submucosal dissection has been recommended for the treatment
of large colorectal tumors. However, the use of this procedure for this indication
is not widely accepted because of its technical difficulty and because of the risk
of complications [1]
[2]. In order to minimize damage to deeper tissues, we have developed a novel endoscopic
electrosurgical knife, the “B-Knife” (BSBK21S35/45; Zeon Medical Inc., Tokyo, Japan),
that uses a bipolar current system.
The B-Knife has a diffusion electrode attached to the tip of its sheath and an active
electrode attached to the knife on the end of the sheath. Needle length can be adjusted
from 0 mm to 3.0 mm. The knife also has a special resinoid coating which enables the
current of electricity per unit area so-called “electric current density”. Because
the knife has been designed so that high-frequency electricity flows from the knife
to the sheath tip, the amount of high-frequency current sent from the knife tip to
the muscle layer has been reduced (Figure [1]). In our experiments using resected colonic material from swine, no vertical electrothermal
degeneration was detected in the muscularis propria after use of the B-Knife (ICC200,
ERBE, set to 120 watts, effect 2, Endo-Cut mode off, and turned on for 15, 30, or
45 seconds).
Figure 1 The B-Knife. a Photographic image showing the knife beside a millimeter scale. b Schematic view, showing the flow route of high-frequency electric current from the
knife to the sheath tip.
Endoscopic submucosal dissection was carried out in three patients using the B-Knife
after informed consent was obtained. In all cases, 10 % glycerin was injected into
the submucosal layer. The electronic instrument was set at 30 watts, forced coagulation
mode [3]
[4]. En bloc resection was achieved in all three cases (Figure [2], Video 1). None of the patients developed delayed bleeding or perforation. No recurrence was
found on follow-up colonoscopy at 3 months.
Figure 2 A large sessile lesion, 65 mm in diameter, in the upper rectum. En bloc resection
was achieved by endoscopic submucosal dissection, which was performed using the B-Knife
(Video 1). The operating time was 50 minutes and there were no complications. Histopathologic
evaluation revealed the lesion to be well-differentiated adenocarcinoma (depth of
submucosal invasion 1000 μm); the margins were free of neoplasia.
These preliminary results suggest that endoscopic submucosal dissection using the
B-Knife is a reliable and safe method for the complete resection of selected large
flat lesions in the colorectum.
Endoscopy_UCTN_Code_TTT_1AQ_2AD
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online content including video sequences viewable at:
www.thieme-connect.de/ejournals/abstract/endoscopy/doi/10.1055/s-2006-944622
