Endoscopic Repair of Colon Perforations
By John LeBas
When Gottumukkala S. Raju, M.D., first began experimenting with a nonsurgical method of repairing colon perforations, there was virtually no U.S. experience with such an approach and only a rudimentary technique. He and his colleagues had to develop a system essentially from scratch, not knowing whether it would ever prove useful.
More than a decade later, following extensive experiments in laboratory animals and preliminary application in human patients, Dr. Raju has shown that the endoscopic perforation closure method can offer an alterative to surgery. With further refinements, invasive repair of colon perforations—a major complication of colonoscopy—may largely become a thing of the past, he said.
“Perforations during colonoscopy are rare, but when they occur, the patient has to be sent to surgery to have the hole repaired,” said Dr. Raju, a professor in The University of Texas MD Anderson Cancer Center’s Department of Gastroenterology, Hepatology and Nutrition, whose main interest is colon cancer prevention. “There are two main problems with this. One, you have to make a big hole in the abdomen to close a small hole in the colon. And two, it gives a lot of bad press to colonoscopies. If a person suffers a perforation, his family and friends may hear about it and never go in for colon cancer screening.”
Setting and early experiments
Perforations generally occur during colonoscopies as a result of the physician unintentionally puncturing the thin colon wall while manipulating the endoscope up through adhesions or scar tissue from prior abdominal surgeries, pelvic surgeries, or radiation, or while a polyp is being cut from the colon wall. Trying to remove large polyps, flat lesions, and residual polyp tissue that has become tethered to the colon wall with scar tissue following a previous removal attempt can also cause a perforation.
Because colonoscopies are essential in preventing colon cancer, Dr. Raju saw a need to limit the negative effects of perforations. It was the late 1990s, and while at a conference he came across a simple yet inspiring product: clips designed to stanch bleeding during endoscopic procedures.
“I thought to myself that these clips could probably be used to close perforations as well, but they would need to provide secure closure of the hole,” he said. “So we began experimenting at The University of Texas Medical Branch at Galveston to see whether this could be done.” The first successful experiments, reported in the early 2000s, showed proof of concept in pigs: the clips were able to be placed endoscopically, cinching down linear perforations up to 7 cm and resulting in leak-proof seals.
Encouraged by the results, Dr. Raju and colleagues made their next experiments tougher by trying to clip circular holes. Adjustments to the technique showed this could usually be done as well. For those holes that couldn’t be clipped closed, a new suturing device developed by another researcher provided a successful alternative approach. A subsequent multicenter trial using animals showed that surgical and endoscopic perforation repair yielded similar outcomes but with fewer adhesions resulting from endoscopy.
More recent animal experiments conducted at The University of Texas Medical Branch at Galveston (with collaborators Ijaz Ahmed, M.D., and Guillermo Gomez, M.D.) involved removing sections of colon from animals and using clips or sutures to close the defect. These experiments were conducted to develop techniques to remove polyps that are tethered to the colon wall by removing a section of the wall and then closing the defect, all through an endoscope. The experiments also proved successful, with no resulting perforations or leaks.
Following the positive animal experiences, Dr. Raju was able to use the endoscopic repair techniques in people who were not candidates for surgery owing to comorbidities. In one patient, clips were used to close a gastric fistula following esophageal cancer surgery. Another patient—a woman with colon cancer who was obese and had a pulmonary embolism—underwent endoscopic repair of a colon fistula to the skin. The patient’s output from the fistula reduced from 100 cc per day to 5 cc per day immediately following closure, and the fistula healed after a few months without the need for surgery.
Application of these endoscopic closure techniques could help physicians attempt endoscopic resection of large polyps or flat lesions that are otherwise sent to surgery for fear of perforation, Dr. Raju said. “Hopefully, our next step is to test this procedure in patients who have benign colon polyps tethered to the colon wall that would be difficult to remove endoscopically, polyps that would otherwise require surgery,” said Dr. Raju, who plans to collaborate with a laparoscopic surgeon. “If we can do a good job removing such polyps and repairing the defects endoscopically, we may eventually be able to eliminate surgery for most patients with difficult benign polyps.”
For more information, contact Dr. Raju at 713-794-5073.
Other articles in OncoLog, June 2010 issue: