Abstract
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. Five anorectal specimens were examined employing hematoxylin and eosin staining and immunohistochemistry for S100 and PGP9.5 to evaluate hemorrhoidal cushion position and nerve distribution. Ninety-three patients undergoing sclerotherapy or rubber band ligation (RBL) with MDL as reference were followed using symptom questionnaires and complication assessments.
Results
(1) A distinct MDL was identified above the dentate line in 69.08% of participants under white light imaging, increasing to 96.14% under NBI (
p
p
= 0.038) and keratinized mucosa below the dentate line (
p
Conclusion
The upper border of ATZ can serve as a reliable endoscopic landmark for safe and effective treatment of internal hemorrhoid therapy, likely due to its anatomical relationship with the hemorrhoidal cushions and preservation of the ATZ.