Frontiers in Medicine
Upper border of anal transitional zone: a new landmark for endoscopic internal hemorrhoid therapy
Background and aim Endoscopic therapies are important approaches for managing internal hemorrhoids. This study assessed the feasibility of endoscopic examination of the upper border of anal transitional zone (ATZ) and its clinical utility and underlying anatomical basis as a landmark for internal hemorrhoid. Methods Mucosal demarcation line (MDL) and the dentate line were identified and measured in 207 adults using white-light and narrow band imaging (NBI) endoscopy, with three biopsies for histologic confirmation. …