Submucosal tunnelling techniques for Zenker's diverticulum: a systematic review of early outcomes with pooled analysis

In the last decade, flexible endoscopic septotomy has been reported as a well-tolerated and effective treatment for Zenker's diverticulum. More recently, novel endoscopic submucosal tunneling techniques, namely Zenker-PerOral Endoscopic Myotomy (Z-POEM) and PerOral Endoscopic Septotomy (POES) have been proposed to obtain complete muscular septum exposure and deeper myotomy. The aim of this study is to provide a systematic review with a meta-analysis of the first experiences of third space approaches for Zenker's diverticulum. Electronic databases (Medline, Scopus, EMBASE) were searched up to October 2020. Studies including patients with symptomatic Zenker's diverticulum who underwent endoscopic treatment by submucosal tunneling technique were eligible. Procedural, clinical and safety outcomes were assessed by pooling data with a random-effect model to obtain a proportion with a 95% confidence interval. Nine retrospective studies were eligible for inclusion (196 patients). Five studies were performed in the USA, two in Europe and two in Asia. Endoscopic treatment was feasible in 96.9% (I²= 0%) of patients. The mean procedure duration was 36.4 ± 14.3 minutes. Clinical success was achieved after 93.4% (I²= 0%) of procedures. The overall adverse events rate was 4.9% (I²= 0%). No differences between the two approaches (Z-POEM vs POES) have been shown in terms of both efficacy and safety. Submucosal tunneling techniques appear to be feasible for symptomatic Zenker's diverticulum, with promising results in terms of efficacy and safety outcomes.