Endoscopic Submucosal Dissection for Colorectal Tumors in the Dentate Line Area and Those Adjacent to the Dentate Line

Colorectal Endoscopic Submucosal Dissection (ESD) is technically more difficult, as compared to gastric ESD, and a higher incidence of associated accidental events still poses a great concern. The mainstay of treatment for tumors in the bowel region from the rectum to the anal canal is shifting from surgery to ESD. ESD for a lesion in the dentate line area differs from that for common colorectal lesions in terms of anatomic characteristics and attention must be paid to some points in particular. At the time of incision of the anal side of the lesion, because the orientation may be difficult to determine, the visual field should be expanded using an attachment. In order to prevent bleeding, care should be taken to prevent deep incision on the anal side of the lesion so as to avoid damage to the venous plexus. Intraprocedural pain should be sufficiently controlled by local or intravenous injection of anesthetics.