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Technology May Bring Kinder, Gentler Colonoscopy

Computer guidance and better sedation could lessen discomfort, experts say

WEDNESDAY, May 24, 2006 (HealthDay News) -- A new, better-controlled colonoscopy system could take much of the discomfort out of the potentially life-saving procedure, developers say.

The advance could also boost screening rates, said experts gathered Tuesday at the annual Digestive Disease Week 2006 meeting in Los Angeles.

"One of the reasons we aren't doing enough colonoscopies is reluctance [on the part of patients] to undergo them," said Dr. Jacques Van Dam, professor of medicine at Stanford University School of Medicine. "It's an invasive procedure and it's uncomfortable."

But, according to its developers, the new system prevents an uncomfortable "bunching up" of the flexible colonoscope as it is inserted into the colon.

Another team said a new sedating-drug regimen can also relieve colonoscopy discomfort, compared to methods of sedation currently in use. This new form of sedation promises a faster recovery -- even enabling patients to drive themselves home after the procedure.

The American Cancer Society and other organizations recommend that individuals at average risk for colon cancer be screened for the disease with colonoscopy or other methods beginning at age 50.

In a typical colonoscopy, patients first consume a liquid diet and take laxatives to cleanse the bowel. During the actual procedure, they lie on their side on the exam table, usually sedated, and the doctor inserts a long, flexible lighted tube into the rectum and then guides it into the colon. This tube transmits an image of the interior of the colon to a video screen, which the doctor uses to check for cancer-linked polyps.

The exam takes 15 to 30 minutes.

In a conventional colonoscopy, Van Dam said, the colonoscope "is akin to a garden hose." The tip of it can be controlled, but as it is inserted and makes its way into the colon, it can form loops, which can produce discomfort.

"With NeoGuide Colonoscopy system, as the endoscopist steers the head, a computer maps where that tip is going and controls the tube behind it," said Van Dam, who is also chairman of the scientific advisory board for NeoGuide Systems, based in Los Gatos, Calif. "It's like a snake following its head."

Last year at the same meeting, "bench-top testing" of the device was presented, showing that the amount of force in the model was less than half that of a standard colonoscope, Van Dam said.

The tubing has "articulated hinges," he said, making it more flexible and less likely to form loops. It's an entirely new system, not simply software that can be added to an existing colonoscopy system.

In the first trial, conducted in Germany, 10 patients who underwent colonoscopy with the new system reported no complications when contacted up to 30 days later. All said they would undergo it again. However, Van Dam stressed that larger studies are needed to confirm these early results.

The new system is due to become available in the United States next spring, he said. The cost difference between a traditional colonoscopy and one performed by the NeoGuide system is unknown at this point, according to the company. The U.S. Food and Drug Administration granted NeoGuide its approval to market the system this past February.

The drugs doctors use to sedate patients for colonoscopy may also be improving.

Use of Entonox -- an inhaled mixture of 50 percent nitrous oxide and 50 percent oxygen -- resulted in less pain for colonoscopy patients than conventional sedation with fentanyl and midazolam (Versed), according to Dr. Sushil Maslekar, a researcher at the University of Hull, in England.

He assigned 131 patients to receive either Entonox, or traditional sedation. Entonox patients reported less pain and were discharged more quickly after the procedure was over -- 26 minutes with Entonox vs. 44 minutes with traditional sedation.

The Entonox mixture has "been around a while," Maslekar said, and doctors sometimes use it for pain relief. In the study, patients undergoing colonoscopy showed no complications from the sedative and could "drive home after the procedure," he said.

Entonox is administered through a mask, so lighter sedation is a plus, according to Dr. Kenneth Wang of the Mayo Clinic, who moderated the panel. "If [patients] become too sedated, the mask falls off their face."

In related news, a study published this week in the Journal of the American Medical Association concluded that for people under age 80, a colonoscopy probably does not have to be performed at intervals any briefer than every 10 years, and that the benefit of screening those over age 80 may be smaller than experts have previously believed.

More information

To learn more about colonoscopy, visit the U.S. National Institutes of Health.

SOURCES: Jacques Van Dam, M.D., Ph.D., professor, medicine, Stanford University School of Medicine, Stanford, Calif; Sushil Maslekar, M.D., researcher, University of Hull, England; Kenneth Wang, M.D., professor, medicine, Mayo Clinic, Rochester, Minn; May 23, 2006, presentations, Digestive Disease Week meeting, Los Angeles; May 24, 2006, Journal of the American Medical Association
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