Combined Forward and Retroflexion Withdrawal in the Detection of Polyps and Adenoma During Colonoscopy

Colonoscopy is the standard of care for the detection of colorectal polyps and adenoma, and colorectal cancer detection. Despite a meticulous evaluation of the colonic mucosa during colonoscopy, a substantial number of colorectal polyps might be missed and colorectal cancer might not be prevented. Previous studies described a 12-28% of miss-rate for all polyps, a 31% for hyperplastic polyps and 6-27% for adenomas, with a higher miss rate noted for smaller polyps. The lesion missing rate depends on several factors, such as the location on difficult areas to be evaluated with conventional colonoscopes (the proximal side of the ileocecal valve, haustral folds, flexures or rectal valves), a flat shape, an inadequate bowel preparation and inadequate endoscopy technique, a time-limited colonoscope withdrawal. If the standard 140º angle of view colonoscope is used approximately 13% of the colonic surface is unevaluated. The incorporation of colonoscopes with a 170-degree wide angled could improve adenoma detection rate. The introduction of high definition (HD) colonoscopes and visual image enhancement technologies, such as narrow band imaging (NBI, Olympus America, Center Valley, PA), I-SCAN™ (Pentax Medical, Montvale, NJ) and Fuji Intelligent Chromo-Endoscopy (FICE™, Fujinon Endoscopy, Wayne, NJ) have improved the lesion characterization; however, several studies have failed to prove an increase in the adenoma detection rates. The Third Eye Retroscope (Avantis Medical Systems, Sunnyvale, CA) is a disposable retrograde viewing device advanced through the accessory channel of a standard colonoscope. It allows retrograde viewing behind colonic folds and flexures simultaneously with the forward view of the colon. Although it shows an increase in the adenoma detection rate by 11%-25%, it has many disadvantages. First, it requires a separate processor and the device is disposable, increasing the cost of the procedure. Second, it occupies the working channel of the colonoscope, limiting the ability to suction. Third, if a polyp is detected, the viewing device has to be removed in order to perform the polypectomy. Fourth, the optic is not high definition and finally, the endoscopist has to get used to visualizing and processing two simultaneous video streams from the colonoscopy and from the retroscope device.

Sex

All

Minimum age

45 Years

Maximum age

80 Years

Inclusion Criteria:

* Patients capable of providing written consent
* Colonoscopy indicated for colorectal cancer screening or surveillance
* Patients submitted for polypectomy
* Colonoscopy indicated for diagnostic purposes: anemia, abdominal pain, constipation, alteration of bowel habits.

Exclusion Criteria:

* Patients under 45 years and over 80 years of age.
* Pregnancy and/or nursing.
* Patients with past-medical history of cardiac, renal, hepatic or severe metabolic diseases
* Unable to tolerate sedation
* Severe uncontrolled coagulopathy
* Past surgical history of colonic resection, ileostomy or colostomy.
* Previous abdominal or pelvic radiation therapy.
* Patients with inflammatory bowel disease, polyposis syndrome or acute diverticulitis.
* Patients with high suspicion of colonic obstruction or history of prior obstruction.
* Patients with gastrointestinal bleeding.
* Inadequate bowel preparation. The bowel preparation will be evaluated using the Boston Bowel Preparation Scale. Patients with \< 2 points in at least one of the three segments of the colon will be excluded.
* Patients who after the beginning of the colonoscopy have to be suspended due to the inability to reach into the cecum because of unfavorable anatomy or impassable tumors/stenosis.