Development of a gel dedicated to gel immersion endoscopy

Safe and Efficient Procedures and Training System for Endoscopic Submucosal Dissection

Recent improvements in endoscopists' skills and technological advances have allowed endoscopic submucosal dissection (ESD) to become a standard treatment in general hospitals. As this treatment entails a high risk of accidental perforation or hemorrhage, therapeutic procedures and training methods that enable ESD to be conducted more safely and efficiently are constantly being developed. This article reviews the therapeutic procedures and training methods used to improve the safety and efficiency of ESD and describes the ESD training system used in a Japanese university hospital at which the number of ESD procedures has gradually increased in a newly established Department of Digestive Endoscopy. During the establishment of this department, the ESD perforation rate was zero among all procedures, including those conducted by trainees.

Successful planned piecemeal endoscopic resection using gel immersion and an over-the-scope clip for a lesion extensively extended into the colonic diverticulum

Video 1Successfully planned piecemeal endoscopic resection using gel immersion and an over-the-scope clip for a lesion extensively extended into the colonic diverticulum.

Endoscopic hemostasis using gel immersion endoscopy for duodenal ulcer and a sigmoid colon polyp: A novel gel injection method

Gel immersion endoscopy (GIE) has gained prominence for securing a good visual field. Traditionally, OS-1 jelly (Otsuka Pharmaceutical Factory) has been used for GIE. However, due to the presence of electrolytes, it is unsuitable for endoscopic hemostasis using a monopolar device. Therefore, VISCOCLEAR (Otsuka Pharmaceutical Factory), a new gel that does not contain electrolytes, has been developed. Moreover, unlike water or saline, VISCOCLEAR does not readily mix with blood, making it effective in visualizing gastrointestinal bleeding. We report two cases in which GIE was performed using a novel gel injection method.

A feasibility study comparing gel immersion endoscopic resection and underwater endoscopic mucosal resection for superficial nonampullary duodenal epithelial tumors

BACKGROUND

Although gel immersion endoscopic resection (GIER) is a potential alternative to underwater endoscopic mucosal resection (UEMR) for superficial nonampullary duodenal epithelial tumors (SNADETs), comparisons between the two are currently insufficient.

METHODS

40 consecutive procedures performed in 35 patients were retrospectively reviewed; the primary outcome was procedure time, and the secondary outcomes were en bloc and R0 resection rates, tumor and specimen size, and adverse events.

RESULTS

Lesions were divided into GIER (n = 22) and UEMR groups (n = 18). The median (range) procedure time was significantly shorter in the GIER group than in the UEMR group (2.75 [1-3.5] minutes vs. 3 2 3 4 5 6 7 8 9 10 minutes; P = 0.01). The en bloc resection rate was 100 % in the GIER group, but only 83.3 % in the UEMR group. The R0 resection rate was significantly higher in the GIER group than in the UEMR group (95.5 % vs. 66.7 %; P = 0.03). The median specimen size was larger in the GIER group than in the UEMR group (14 mm vs. 7.5 mm; P < 0.001). The tumor size was not significantly different between the groups and no adverse events were observed.

CONCLUSIONS

GIER is efficacious and safe to treat SNADETs, although additional studies are needed.

Factors contributing to changes in viscosity and flow rate of a dedicated gel for gel immersion endoscopy

Background and study aims  Gel immersion endoscopy is a novel technique for securing the visual field during endoscopy. Clinical application of a dedicated gel for this technique with an appropriate viscosity to prevent mixing with blood and its efficacy was reported. The aim of this study was to evaluate changes in gel viscosity and flow rate under different conditions. Methods  The viscosity of the gel after injection and flow rate were measured under various conditions changing the injection route and method. Gel viscosity was measured at 25, 10, and 4 °C. Results  A decrease in gel viscosity was found when the gel was injected via the water jet channel compared to the accessory channel. The flow rate and decrease in viscosity of the gel injected via the water jet channel were 220 mL/min and 63.2 %, while when injected via the accessory channel with a clip device inserted were 560 mL/min and 35.8 %. When the gel was kept at a low temperature, the viscosity increased. Conclusions  Gel injection via the accessory channel should be the first choice for efficient use considering the viscosity and flow rate.