PRACTICE PATTERNS, TECHNIQUES, AND OUTCOMES OF FLEXIBLE ENDOSCOPIC MYOTOMY FOR ZENKER'S DIVERTICULUM: RETROSPECTIVE, MULTI-CENTER STUDY.

BACKGROUND AND AIMS Flexible endoscopic myotomy has been increasingly performed for Zenker's diverticulum (ZD) using various endoscopic techniques and devices. The main aim of this study was to assess practice patterns and compare outcomes of endoscopic myotomy for ZD. PATIENTS AND METHODS Cases performed at 12tertiaryendoscopy centers from 1/2012-12/2018 were reviewed. Patients ≥18 years old with dysphagia and/or regurgitation, and ZD who underwent endoscopic myotomy were included. Outcomes assessed included technical success, clinical success and adverse events. RESULTS 161 patients were included. Traditional endoscopic septotomy was most commonly performed (137/161, 85.1%) followed by submucosal dissection on the septum and myotomy (24/161, 14.9%). Hook knife (43/161, 26.7%) and needle knife (33/161, 20%) were most commonly used. Overall, technical and clinical success was 98.1% (158/161) and78.1% (96/123). Adverse events were noted in 13patients (8.1%). There was no significant difference in technical and clinical success between traditional septotomy and submucosal dissection groups (97% vs 95.8%, p = 0.559 and 75.2% vs 90.9%, p = 0.155, respectively). Clinical success was higher with hook knife (96.67%), compared to needle knife (76.6%) and insulated tip knife (47.1%). Outcomes were similar between centers with > 20, 11-20 and <10 cases performed. CONCLUSIONS Flexible endoscopic myotomy is an effective therapy for ZD with a low rate of adverse events. There was no significant difference in outcomes between traditional septotomy and a submucosal dissection approach, or with centers with higher volume, though clinical success was higher with the hook knife.