Anatomical extent of fiberoptic sigmoidoscopy.

The anatomical extent of fiberoptic sigmoidoscopy was determined by placing a clip on the colonic mucosa and subsequently locating the clip on barium enema. A 60 cm exam viewed the entire sigmoid colon in 81% of patients. Exams of 50-55 cm, 40-45 cm, and 30-35 cm extent viewed the entire sigmoid colon in 68%, 27%, and 13%, respectively. The 50-55 cm and 60 cm exams collectively viewed 90% and 95% of the sigmoid colon surface, respectively. The 30-35 cm and 40-45 cm exams collectively viewed 53% and 70% of the sigmoid colon surface respectively. The anatomical extent of fiberoptic sigmoidoscopy clearly exceeds that of rigid sigmoidoscopy. These data help to define the diagnostic potential of fiberoptic sigmoidoscopy.