Investigating deeper: muscularis propria to natural orifice transluminal endoscopic surgery.

Submucosal endoscopy with a mucosal flap (SEMF) safety valve technique is a global concept in which the submucosa is a free working space for endoscopic interventions. A purposefully created intramural space provides an endoscopic access route to the deeper layers and into the extraluminal cavities. The mucosa overlying the intramural space is protective, reducing contamination during natural orifice transluminal endoscopic surgery (NOTES) procedures and providing a sealant flap to repair the entry point and the submucosal space. In addition to NOTES, SEMF enables endoscopic achalasia myotomy, histologic analysis of the muscularis propria, and submucosal tumor removal.