Background: Endoscopic mucosal resection with a cap-fitted endoscope appears to be as effective but easier to perform than freehand mucosectomy. However, experience with this technique has been limited to small case series and there is a lack of data from direct comparison trials. Methods: Nine pigs were randomized to mucosectomy using a cap-fitted endoscope or the freehand technique. Five mucosal resections were performed at five different sites in the gastric body in each pig. Eight to ten milliliters of a saline, epinephrine, and methylene blue solution were injected to raise a bleb to simulate a mucosal lesion. Endoscopic mucosal resection with a cap-fitted endoscope was performed by suctioning the bleb into the cap device pre-looped with an oval snare; mucosectomy was performed electrosurgically. Freehand mucosectomy was performed by encircling and then resecting the bleb using an oval snare. The ease of procedure (1 = 'very easy' to 5 = 'unable to complete') was assessed after each resection. The animals were recovered, maintained, and then humanely sacrificed after 2 weeks. Results: Five pigs underwent endoscopic mucosal resection with a cap-fitted endoscope and 4 underwent freehand mucosectomy. Eight animals survived for 2 weeks without complications and one animal from the freehand group died of massive hemorrhage within 48 hours of endoscopy. Both methods produced rounded resection specimens measuring 9 to 12 mm in diameter of the full thickness of the mucosa and the submucosa. Overall ease of resection was 1.84 ± 0.52 for the cap-fitted group and 2.98 ± 0.86 for the freehand group (p < 0.0001). All of the sites identified at autopsy were completely re-epithelialized, except for the five sites found in the pig that died prematurely. Conclusions: Endoscopic mucosal resection with a cap-fitted endoscope is as effective, safe, but easier to perform compared with freehand mucosectomy.
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