POEM for special patient cohorts: A review.

Peroral endoscopic myotomy (POEM) is a natural orifice, translumenal endoscopic surgical procedure that achieves endoscopic myotomy by conducting a submucosal tunnel as an operating space. It is conventionally performed in achalasia. Recently, several centers worldwide have reported the feasibility of this procedure not only in early achalasia but also in other particular patient cohorts. Possible indications for POEM include previously failed Heller myotomy, pneumatic balloon dilatation or POEM, sigmoid achalasia, pediatric patients, spastic esophagus disorders, Zenker's diverticulum and gastroparesis. However, its application in large numbers of special patient groups awaits knowledge of the long-term outcome and greater experience with POEM.