A simple mathematical equation for reliable prediction of gastro-esophageal junction (GEJ) through the sub mucosal tunnel during per oral endoscopic myotomy (POEM) - A proof of concept pilot study

Per oral endoscopic myotomy (POEM) is an accepted treatment for achalasia cardia (AC). Accurate estimation of distance to gastro-esophageal junction (GEJ) through the tunnel is often a technical challenge during POEM. Currently employed methods have limited accuracy. Tunneling is often performed by periodically alternating between tunnel and lumen to ensure extension up to and beyond GEJ. An error at this step may lead to an incomplete myotomy; and procedure time may be prolonged. We have observed that distance to GEJ measured through the tunnel is longer than when measured through the esophageal lumen.