Submucosal endoscopy: a novel approach to en bloc endoscopic mucosal resection (with videos)

BackgroundThe submucosal layer is of eminent importance for endoscopic mucosal resection (EMR) in the GI tract.ObjectiveDevelopment of submucosal endoscopy, which allows diagnostic and therapeutic endoscopy of the submucosal space (SS) in the esophagus.DesignAcute experiments in a live porcine model.InterventionsAn area in the esophagus was marked with a diathermic probe to define a mucosal piece for resection. After local infiltration, a 1- to 2-cm transverse incision was performed 1 to 2 cm proximal and distal of these margins. We entered the SS with a flexible small-caliber videoendoscope through the proximal incision and dissected the fibrous submucosal connective tissue in a longitudinal direction with a blunt forceps. For EMR, the lifted mucosa was subsequently separated by use of an insulated-tip hook needle-knife.Main Outcome MeasurementsEn bloc resection of prespecified mucosal areas.ResultsA total of 15 mucosal pieces were resected in 4 pigs. The size of the resected pieces varied from 1.6 cm × 0.9 cm to 7.4 cm × 1.7 cm ex vivo. In a fifth pig, 2 circular mucosectomies (lengths 3.0 cm and 1.6 cm) were done. All mucosal pieces could be completely resected en bloc. The endoscopic view in the SS was excellent. There were no procedure-related complications.LimitationsThe method has not yet been evaluated in humans.ConclusionsEntering the SS for submucosal endoscopy is a novel, innovative, and practicable method for the dissection of mucosal neoplastic lesions. We demonstrated that mucosal areas of various sizes could be resected en bloc without complications.