Acceptability, Safety, and Feasibility of Transnasal and Peroral Ultrathin Endoscopy Using GAGLESS Mouthpieces: A Prospective Randomized Trial

Background/Aim: Esophagogastroduodenoscopy (EGD) is an effective screening method for early detection of gastric cancer. The GAGLESS mouthpiece has a structure that widens the pharyngeal cavity and suppresses the pharyngeal reflex. This study aimed to investigate the acceptability, safety, and feasibility of transnasal and peroral ultrathin endoscopy using GAGLESS mouthpieces (Clinical Trial Number: UMIN000036922). Patients and Methods: This study was a multicenter, prospective, randomized, open -label trial performed using a questionnaire. The study included 101 consecutive patients who visited the participating medical institutions between June 2019 and March 2022 (median age=47 years, range=24-87 years; all male). Patients aged >= 20 years at the time of consent acquisition who were the first to undergo EGD were included in the study. The primary endpoint was the degree of distress during EGD, as determined using a visual analog scale (VAS). Results: The VAS score during endoscopic passage through the pharynx was significantly better in the transnasal endoscopy group than in the oral endoscopy group (2.420 vs. 4.092, p=0.001). There was no significant difference in the VAS scores between the two groups during anesthesia or throughout the examination. Compared with nasal endoscopy, oral endoscopy with a GAGLESS mouthpiece did not reduce the VAS score but did significantly improve gastric visibility. Conclusion: For patients in whom there was difficulty in inserting a nasal endoscope, using a GAGLESS mouthpiece rather than a conventional mouthpiece may be more useful in reducing pain.