Standard sigmoidoscope is 60 cm. long and leaves 90-110 cm. of colon unexamined.
60-cm scope can examine the entire sigmoid colon in approximately 80% of patients and can detect 40-65% of polyps and cancers f the colon.
35-cm scope can access only 50-75% of the sigmoid colon and can detect only 35-45% of colorectal polyps and cancers.
Flexible sigmoidoscopy associated with at least a 30% reduction in colorectal cancer related mortality in case-controlled studies.
Detects from two thirds to four fifths of the advanced cancer found by colonoscopy.
Flexible sigmoidoscopy associated with approximately I in 5000 screening subjects hospitalized for gastrointestinal complication, and 1 in 16,000 hospitalized for a serious complication.
Flexible sigmoidoscopy associated with colonic perforation, serious bleeding and diverticulitis leading to surgery occurs less often than 1 in 50,000 examinations.
Potential complications include colitis from chemicals used for endoscope sterilization, bowel perforation, bleeding and infection.
Acute diverticulitis may be related to flexible sigmoidoscopy because it is a microscopic perforation of the colon, and perforation may be induced by mechanical or pneumatic trauma during the procedure.