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Screening colonoscopy has been shown to be less effective in preventing colorectal cancer in the proximal colon compared to the distal colon. Possible reasons for this include bowel preparation often being worse in the proximal colon as well as flat depressed lesions being more common in the proximal colon.

Retroflexion is commonly regarded as standard practice in the rectum, but retroflexion in the proximal colon is not currently routinely performed due to concerns of perforation and possibly because of the increased time required.

Proximal colon retroflexion has been shown to be safe and effective without any complications, but data regarding ability to retroflex with certain types of colonoscopes is limited. Endoscopists interchangeably use standard adult colonoscopes or pediatric colonoscopes. Studies have not been performed to comparatively evaluate the success rates of standard adult and pediatric colonoscopes and whether either type of instrument confers a greater polyp detection rate.

Inclusion Criteria:

• Adult patients over the age 18 undergoing screening or surveillance colonoscopy

Exclusion Criteria:

• Age less than 18
• Pregnant
• History of ulcerative colitis or Crohn's disease
• History of polyposis syndromes
• History of colon resection
• Colonoscopy being performed for diagnostic purposes (ie. bleeding, abdominal pain, alternating bowel habits)