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Stories of ESD Device Development

ITknife

Takuji Gotoda, National Center for Global Health and Medicine

I became a resident in the Endoscopy Division at the National Cancer Center Hospital in June 1995. At that time, Dr. Koichi Hosokawa (presently at Suwa Central Hospital) who was an inventive-minded man was attempting to improve the needle knife for use in ERHSE. After developing distal tips from various materials aimed at preventing perforation, he eventually arrived at what is now called ITknife. When I returned to the Endoscopy Division after completing my rotation in 1996, the chief resident, Dr. Hiroyuki Ono (currently Director, Endoscopy and GI Oncology Division, Shizuoka Cancer Center) was struggling with ESD using ITknife and experiencing difficulties that are unimaginable today. The lucky thing for me was that there was no other resident specialising in the upper gastrointestinal tract at that time. I was able to gain experience with ITknife by assisting Dr. Ono. I originally became a Cancer Center resident with the hope of working in colonoscopy, but a happy combination of coincidence and luck led to my encounter with Dr. Hosokawa, Dr. Ono, and ITknife.

ITknife2

Hiroyuki Ono, Shizuoka Cancer Center

I have experienced few problems with ITknife, other than the fact that the cutting performance tends to deteriorate in cases with severe fibrosis such as ulcer scars. A few other doctors have also noted that lateral cutting is difficult with ITknife and that the ceramic tip at the distal end catches in the mucosa. So I decided to try and find a way to improve the cutting performance of the conventional ITknife while maintaining its advantages. My idea was to attach the three short blades shaped like the three-pointed star of Mercedes-Benz at the bottom of the ceramic tip which are perpendicular to the conventional knife blade. I proposed this idea to Olympus for actual prototyping. When I applied the prototype in an actual clinical procedure after confirming its safety with a pig stomach, I was surprised by how well the cutting ability increased. I convinced myself with Drs. Inui and Hasuike saying that it would be hard to go back to the conventional ITknife once you have used ITknife2 and that this would be the definitive version for the ITknife technique.

HookKnife

Tsuneo Oyama, Saku Central Hospital

It started when I intentionally bent the distal end of a needle knife myself, thinking that I would be able to incise and dissect the mucosa more safely if the distal end of a needle knife were bent into an L-shape so that it could hook the mucosa before cutting. Later, I asked Olympus to create a similar prototype, which was later provided with a rotation function and eventually commercialised.

FlexKnife

Naohisa Yahagi, Keio University

In the beginning, we were looking for a knife that was flexible, easy to manipulate and had an adjustable distal end length. We noticed that the distal end of the thin snare (SD-7P) can be used to incise the mucosa and initially performed ESD as a thin snare technique. But this technique brings with it such problems as variation of the distal end length or splitting of the wire’s distal end during a procedure. We therefore created FlexKnife by increasing the wire strength and adding a stopper mechanism.

TriangleTipKnife

Haruhiro Inoue / Hitomi Minami / Yoshitaka Sato, Showa University Northern Yokohama Hospital

Hooks are used in basic surgical procedures (laparoscopic cholecystectomy), as well as in ESD. Axis alignment was difficult when using a flexible endoscope, so I invented TriangleTipKnife. This had three tips at the distal end pointing in three different directions, which act like hooks, but do not need axis alignment.

DualKnife

Naohisa Yahagi, Keio University

As suggested by the word “dual,” DualKnife can be set to either of two lengths, eliminating the need for the precise knife length adjustment required with FlexKnife. The needle knife design of DualKnife provides sharp incision performance, as well as easy removal of any tissue that coagulates on the knife tip. In addition, even when the knife is retracted completely, the small disc on the tip remains projected so that it can easily be used for coagulation and hemostasis by contact. In my opinion it is a safer, easier-to-use knife than FlexKnife, solving the problems I experienced with FlexKnife.

Support Devices

Toshihiko Doi, National Cancer Center Hospital East

ESD has proven that it can expand the indications and improve the curability of EMR. However, ESD’s practice remains limited and it is relegated to a minor position in the hierarchy of EMR procedures. When considering how to establish ESD as a more universal technique, keep in mind that the basic endoscopic treatment is biopsy. This led us to the idea that we should try to develop a mucosal incision technique that resembles biopsy. What usually throws off first-time users of ITknife is that, while previous treatment devices are manipulated with a pulling action, ESD with ITknife depends on advanced endoscope manoeuvring except for the sections that can be cut by pulling ITknife. In particular, the actions required to make introductory holes with a needle knife tend to be very unstable. So, keeping in mind that biopsy-style manipulations are the cornerstone of any endoscopic treatment, I began to search for a way to perform ESD using similar manipulations. My first thought was that it would be safer if a hole could be made by grasping the mucosa via the introductory holes and then supplying current. We also designed HotClaw as a tool for lifting the mucosa for incision and dissection.
Our intention was to reduce the risk of perforation by applying an upward force instead of a downward cutting force. For Coagrasper, we focused on how to stop bleeding — one of the most critical complications associated with ESD — more quickly and more effectively. Some hospitals still use the hot biopsy forceps for hemostasis, but as a device exclusively designed for hemostasis, Coagrasper’s shape and electrical characteristics are suitable
for hemostasis. Our goal has always been to develop an ITknife technique that is safe and that can be performed by beginners.