The A to Z of Peroral Endoscopic Myotomy.

Peroral endoscopic myotomy (POEM) is a novel technique within the field of third space endoscopy. The overarching principal is creation of a mucosal incision, careful dissection of the submucosal space using an electrosurgical knife to reach the muscularis (ie, tunneling), performing a controlled myotomy, and finally, closure of the mucosal incision. POEM was first developed for the management of achalasia, and now a decade of evidence shows the procedure is safe, effective, and highly reproducible. Since then, the indications for POEM have expanded to a range of benign upper gastrointestinal (GI) pathologies including cricopharyngeal bar (C-POEM), Zenker's diverticulum (Z-POEM), esophageal diverticula (D-POEM), and gastroparesis (G-POEM). POEM offers the benefit of a minimally invasive alternative to surgical intervention with high clinical success and low rate of adverse events. As the field expands, there is need for more high-quality prospective evidence for the use of POEM within the upper GI tract akin to the ground-breaking work that has been achieved in achalasia. Within this review, we discuss the 5 main indications for POEM, the technical aspects of each corresponding procedure, and analyze the current evidence supporting their use in clinical practice.