Figure 1“Underwater” endoscopic submucosal dissection (ESD) for superficial esophageal squamous
cell neoplasms. Arrowheads reveal the appropriate dissection layer, just above the muscularis propria. We finally
achieved complete endoscopic and histologic resection without perforation. A, Flat lesion 50 mm in diameter in the midesophagus. B, Submucosal dissection could be performed seamlessly soon after submucosal injection
by water-jet function with a Jet B-knife. C, Ulcer bed after underwater ESD was performed without perforation. D, Flat lesion, 25 mm in diameter, adjacent to post-EMR scar in the midesophagus. E, Even where it was hard to identify an appropriate dissection plane because of fibrosis,
the underwater technique helped to identify the dissection layer and yielded a more
precise procedure. F, Ulcer bed after underwater ESD was performed without perforation.