Katsuya Kobayashi

Endoscopic submucosal dissection for early gastric cancer using the tip of an electrosurgical snare (thin type)

Background:  Although the strip biopsy method and aspiration method are popular endoscopic mucosal resection techniques for its convenience and reliability, they have limitations in resectable tumor size and location. Endoscopic submucosal dissection techniques using the diathermic needle knife or the insulated‐tip diathermic knife have been introduced to overcome this disadvantage, but they have high risks for bleeding and perforation. Therefore, we have developed a new endoscopic submucosal dissection technique using the tip of an electrosurgical snare (thin type) and assessed its efficacy.

Submucosal Injection of Normal Saline may Prevent Tissue Damage From Argon Plasma Coagulation: An Experimental Study Using Resected Porcine Esophagus, Stomach, and Colon

Argon plasma coagulation (APC) is considered to be a safe thermocoagulation technique, but some reports show perforation and deformity during and after APC. In this study, we investigated the usefulness of prior submucosal injection for APC. APC over the mucosa was performed on fresh resected porcine esophagus, stomach, and colon with prior submucosal injection of normal saline (injection group) and without it (control group). The depth of tissue damage increased linearly with pulse duration up to the shallower submucosal layer in both groups. After that, tissue damage in the injection group remained confined to the shallower submucosal layer under any condition, whereas that in the control group continued to extend. The tissue damages of the injection groups were significantly (P<0.05) shallower than those of the control groups that reached the deeper submucosal layer in all the organs. Submucosal injection of normal saline before the application of APC may limit tissue damage and prevent perforation and deformity.

Safety of argon plasma coagulation for hemostasis during endoscopic mucosal resection.

Showing the safety of argon plasma coagulation (APC) over mucosal defects during/after endoscopic mucosal resection (EMR), 2 studies using resected pig (ex vivo) and living minipig (in vivo) stomachs were performed. As an ex vivo study, APC was applied over mucosal defects in 2 groups; with prior submucosal saline injection and without injection. Only subtle tissue damage was observed in the injection group, whereas apparent damage was observed in the noninjection group. The damaged distances in depth significantly increased as the pulse duration increased and those at the pulse duration of 4 seconds, which might be maximal in clinical practice, were approximately 1 mm. As an in vivo study, APC was applied over mucosal defects immediately after EMR. Only subtle tissue damage was observed even at the pulse duration of 20 seconds as shown in the ex vivo study. APC can be performed safely over the mucosal defects during/after EMR.

Successful Endoscopic EN Bloc Removals of Colorectal Tumors By Endoscopic Submucosal Dissection Using a Flex Knife and a Mixture of High-Molecular-Weight Hyaluronic Acid and a Glycerin Plus Sugar Solution

Successful Endoscopic EN Bloc Removals of Colorectal Tumors By Endoscopic Submucosal Dissection Using a Flex Knife and a Mixture of High-Molecular-Weight Hyaluronic Acid and a Glycerin Plus Sugar Solution Mitsuhiro Fujishiro, Naohisa Yahagi, Naomi Kakushima, Shinya Kodashima, Masanori Nakamura, Hideyuki Miyoshi, Yoshikazu Moriyama, Nobutake Yamamichi, Ayako Tateishi, Katsuya Kobayashi, Takuhei Hashimoto, Keiji Ogura, Masao Omata Background: Endoscopic submucosal dissection (ESD) is a novel therapeutic technique of gastrointestinal tumors. The technique has been developed further by ourselves as a new ESD method using a flex knife (Flexknife , Olympus Co., Tokyo, Japan) and a mixture of 1% high-molecular-weight (1900 KDa) hyaluronic acid (Suvenyl , Chugai Pharmaceutical Co., Tokyo, Japan) and a glycerin plus sugar solution (Glyceol , Chugai Pharmaceutical Co., Tokyo, Japan). The purpose of this study is to investigate our results of ESD for colorectal tumors. Methods: We retrospectively investigated 122 ESD-indicated lesions (a mean tumor size of 27.8 (range: 5-100) mm) in 113 patients those were treated by ESD with our technique at the University Hospital between June 2000 and October 2004. Those underwent ESD because of patients’ desire, etc, even if the lesions were extra-indicated for ESD preoperatively had been excluded beforehand in the data. The 122 lesions were classified into 12 Is-type tumors, 59 laterally spreading tumors with granular type (LSTs-G), 38 LSTs with non-granular type (LSTs-NG), 9 scarring tumors due to previous intensive biopsy or endoscopic therapy, and 4 carcinoid tumors. From the data, we analyzed an en bloc resection rate, final histology, complication, and recurrence. Complication was defined as a life-threatening event such as hemorrhage needed blood transfusion or perforation needed surgical rescue. Results: An overall en bloc resection rate was 92% (113/122) (Is 92%, LST-G 92%, LST-NG 95%, scarring tumors 89%, carcinoid 100%) and all of the tumors could be evaluated by histology. Post-ESD histology revealed 63 adenomas, 44 intramucosal cancers, 11 submucosal invasive cancers, and 4 carcinoid tumors. Three cancers with massive submucosal invasion were additionally treated by surgery with lymph node dissection. No complication needed blood transfusion or surgical rescue occurred. As recurrence, only one rectal adenoma of LST-G with multi-fragmental resection was treated by argon plasma coagulation 2 months after ESD due to Abstracts