Usefulness of a novel slim type FlushKnife-BT over conventional FlushKnife-BT in esophageal endoscopic submucosal dissection.
OBJECTIVE
To investigated the usefulness of a novel slim type ball-tipped FlushKnife (FlushKnife-BTS) over ball-tipped FlushKnife (FlushKnife-BT) in functional experiments and clinical practice.


METHODS
In order to evaluate the functionality of FlushKnife-BTS, water aspiration speed, resistance to knife insertion through the scope, and waterjet flushing speed were compared between FlushKnife-BTS and BT. In clinical practice, esophageal endoscopic submucosal dissection (ESD) performed using FlushKnife-BTS or BT by an experienced endoscopist between October 2015 and January 2016 were retrospectively reviewed. The treatment speed and frequency of removing and reinserting the knife to aspirate fluid and air during ESD sessions were analyzed.


RESULTS
Functional experiments revealed that water aspiration speed by the endoscope equipped with a 2.8-mm working channel with FlushKnife-BTS was 7.7-fold faster than that with conventional FlushKnife-BT. Resistance to knife insertion inside the scope with a 2.8-mm working channel was reduced by 40% with FlushKnife-BTS. The waterjet flushing speed was faster with the use of FlushKnife-BT. In clinical practice, a comparison of 6 and 7 ESD using FlushKnife-BT and BTS, respectively, revealed that the median treatment speed was 25.5 mm2/min (range 19.6-30.3) in the BT group and 44.2 mm2/min (range 15.5-55.4) in the BTS group (P= 0.0633). However, the median treatment speed was significantly faster with FlushKnife-BTS when the resection size was larger than 1000 m2(n= 4, median 24.2 mm2/min, range 19.6-27.7vs n= 4, median 47.4 mm2/min, range 44.2-55.4,P= 0.0209). The frequency of knife replacement was less in the BTS group (median 1.76 times in one hour, range 0-5.45) than in the BT group (7.02 times in one hour, range 4.23-15) (P= 0.0065).


CONCLUSIONS
Our results indicate that FlushKnife-BTS enhances the performance of ESD, particularly for large lesions, by improving air and fluid aspiration and knife insertion during ESD and reducing the frequency of knife removal and reinsertion.
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Yoshiko
Y
Ohara
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Takashi
T
Toyonaga
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Namiko
N
Hoshi
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Shinwa
S
Tanaka
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Shinichi
S
Baba
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Hiroshi
H
Takihara
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Fumiaki
F
Kawara
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Tsukasa
T
Ishida
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Yoshinori
Y
Morita
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Eiji
E
Umegaki
Yoshiko Ohara, Namiko Hoshi, Tsukasa Ishida, Yoshinori Morita, Eiji Umegaki, Takeshi Azuma, Division of Gastroenterology, Department of Internal Medicine, Graduate School of Medicine, Kobe University, Kobe 650-0017, Japan.
Takeshi
T
Azuma
D000368:Aged; D004210:Dissection / Q000295:instrumentation*; D000069916:Endoscopic Mucosal Resection / Q000295:instrumentation*; D004867:Equipment Design; D004945:Esophagoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013525:Surgical Instruments
Ball-tipped FlushKnife; Endoscopic submucosal dissection; Novel slim type ball-tipped FlushKnife; Resistance to knife insertion; Water aspiration speed