The effectiveness of a new multibending scope for endoscopic mucosal resection

Background and Study Aims: Each year at our institution we have been performing over 100 endoscopic mucosal resections (EMRs) for gastric tumor. However, there are some tumor locations where it is difficult to carry out this procedure, such as the lesser curvature or posterior wall of the gastric body, the cardia, and the lesser curvature of the antrum. To facilitate EMR of tumors in these locations, a multibending scope (the "M-scope", Olympus GIF-2T24OM; Olympus Optical, Tokyo, Japan) has been developed, which has two independently curving segments. The aim of this study was to evaluate the effectiveness of this new multibending scope for EMR of gastric tumors. Patients and Methods: Using the M-scope, we carried out EMR in 59 patients at the Jikei University Hospital. The lesions were located in the cardia in seven patients, in the gastric body in 30 patients, and in the antrum in 22 patients. The effectiveness of the M-scope was evaluated by experienced endoscopists; a score of 1 was given for very good effectiveness, and a score of 0 was given when there was no notable difference in effectiveness from the conventional scope. Evaluation was done according to the location of the lesions, the method used for EMR, and the tumor diameter. When the score for each item was equivalent to the average overall score for all the procedures or higher, the M-scope was defined as being effective. Results: The overall score for all the procedures was 0.7 +/- 0.4 (average +/- SD) (very good in 43 procedures; no notable difference in 16 procedures). When assessed according to the location of the lesion, the mean effectiveness scores of the M-scope for lesions at the following locations were higher than the average overall score: the lesser curvature of the antrum (0.8 +/- 0.5); the posterior wall of the gastric body (1.0 +/- 0.0); the greater curvature of the gastric body (1.0 0.0); and the lesser curvature of the gastric body (0.9 +/- 0.4). The results suggested that the M-scope was effective for EMR of gastric tumors at these traditionally difficult locations. With regard to the scores assessed according to the method of EMR, the mean scores were 0.8 +/- 0.4 for the two-channel scope method and 0.9 +/- 0.4 for EMR using an insulated-tip diathermic knife (IT-EMR), again suggesting that the M-scope was effective for EMR by these methods. When evaluated according to tumor size, the score was 0.8 +/- 0.4 when the tumor was 11 mm or greater in diameter, indicating that the M-scope was effective for EMR of large tumors. Conclusion: The results of the study suggest that the M-scope is effective for EMR of tumors in the lesser curvature of the antrum, and in the posterior wall, lesser curvature, or greater curvature of the gastric body. With regard to the method of EMR, the M-scope is effective for both the two-channel scope method and IT-EMR. In relation to tumor size, the M-scope is effective for the resection of large tumors.