{'fraction_non_alphanumeric': 0.022862368541380886, 'fraction_numerical': 0.006858710562414266, 'mean_word_length': 5.0609418282548475, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Endoscopic submucosal dissection (ESD) of early neoplastic gastric lesions using a new double-channel endoscope (the "R-scope").

BACKGROUND AND STUDY AIM
Endoscopic submucosal dissection (ESD) allows en bloc resection of lesions > 2 cm in diameter. However the procedure is difficult because of limited visualization of the cutting area. The aim of this study was to evaluate a new endoscope (the "R-scope") for ESD; this provides a second flexible section for improved positioning capability and two instrumentation channels for vertical lifting of the targeted mucosal area and horizontal cutting of the submucosa.


METHODS
The R-scope was tested first for ESD of 17 predetermined gastric areas in eight anesthetized pigs. Clinical experience was then prospectively obtained in 10 patients with early gastric neoplasia. In both instances, dye-stained saline solution was used for repeated submucosal injection. Various types of knives were available for circumferential cutting of the mucosa to isolate the targeted lesion. The specimen was then lifted and the submucosal layer was dissected with the appropriate type of knife to achieve en bloc resection.


RESULTS
ESD succeeded in 14/17 animal cases (82 %), remained incomplete in two cases and failed in one because of an intractable perforation; a further two small perforations were clipped. In 10 patients (with nine early carcinomas and one adenoma, with a median diameter of 22 mm), lesions were completely resected in six cases. Surgery was necessary in two patients due to early and delayed perforation. Three other patients with small amounts of free air were conservatively managed but elective surgery was performed in two of these patients because of incomplete resection or deep submucosal tumor infiltration.


CONCLUSIONS
The R-scope facilitated ESD of large gastric areas in live animal testing and in a small series of patients However the procedure is technically demanding and time-consuming. It was also associated with a high risk of perforation; this may be related to an insufficient volume of solution being injected submucosally, excessively forceful lifting of the specimen, or the short learning period.