Experimental Device to Improve Colonoscopy

Overview

This study will test the use of a new device called a segmental stiffening wire (SSW) in colonoscopy to correct a problem called looping. Colonoscopy is the best test for detecting early colon cancer and removing growths called polyps, which can become colon cancer. Sometimes the flexible tube (colonoscope) used in the procedure loops at a certain point as it advances through the colon, making it difficult to move further and causing the patient pain from excessive stretching of the colon. The SSW is designed to prevent this by stiffening the part of the tube that would otherwise form the loop. Healthy subjects between 50 and 80 years of age and healthy subjects 40 years and older who have a family history of colon cancer may be eligible for this study. Participants undergo colonoscopy a day after self-administering a bowel cleansing preparation. The first part of the procedure is done similarly to that of a flexible sigmoidoscopy, and no sedation or pain medication is used. The colonoscope is inserted into the rectum and advanced about one-third the length of the colon. Pain or discomfort should be mild to moderate cramping and a feeling of having to move the bowels. The subject is asked to score his or her pain level at this point using a standard pain scale. If there is pain, the procedure is stopped and an x-ray is taken to determine if the colonoscope has looped. If it has, the loop is undone and the SSW is used. Another x-ray is then taken to document that the loop has been prevented with the SSW, and the procedure is completed as per standard medical practice. Subjects are taken to the recovery area, informed of the test results and then discharged home in the care of an accompanying adult.

Colonoscopy can be challenging to perform and painful due to looping of the colonoscope. Looping occurs when further insertion of the colonoscope results in a loop forming in the shaft of the colonoscope instead of advancement of the tip. Attempts have been made to solve this problem, but to date there is no perfect solution. Since colonoscopy is the gold standard for colon cancer screening providing a device that could prevent looping would be valuable. We have developed an experimental device that has not been approved outside of the context of this study known as the Segmental Stiffening Wire (SSW). This wire will be utilized by passing it through the biopsy channel of the endoscope. The wire has a 15-25 inch area of increased thickness and stiffness. The stiffened section can be advanced into areas of looping in an effort to prevent re-looping. We will conduct a pilot study in two phases. The first phase will include approximately 10 healthy volunteers who will undergo colonoscopy using the SSW. Fluoroscopy will be used to determine if the device prevents re-looping. If in phase 1 the device is successful in over 30% of episodes, the second phase will be undertaken. In the second phase volunteers willing to undergo two colonoscopies on consecutive days will be recruited. Volunteers who experience looping will be randomized as to whether the SSW is available. These volunteers will then undergo an otherwise identical colonoscopy on the following day except the SSW will be available if it was not on the first colonoscopy or it will not be available if it was on the first colonoscopy. Volunteers who undergo two colonoscopies will not need a second bowel preparation but will be maintained on a clear liquid diet between the two procedures. Volunteers in which looping does not occur will have their initial colonoscopy completed as normal and then will leave the study. If unable to obtain sufficient volunteers willing to undergo dual colonoscopy, then volunteers willing to undergo single colonoscopy will be included and their procedures will be done with or without the SSW in random fashion. The endpoints will be cecal intubation time; cecal intubation rate; quantity of sedation/analgesia; number of ancillary maneuvers; pain/sedation as measured by the Visual Analog Pain Scale, the Ramsey Sedation Scale, and clinical observations; vital sign changes; and the endoscopists subjective assessment of procedure difficulty and the usefulness of the SSW.