May 25, 2007 To prevent colon cancer, the second leading cause of United States cancer deaths, the American Cancer Society recommends that after age 50 people undergo colonoscopies every ten years to detect signs of that disease -- either actual tumors or precancerous polyps.
But in one out of every 1,000 to 2,000 colonoscopies, doctors inadvertently perforate -- or puncture -- the colon. Most of these patients need urgent surgery to close the wound and spend 10 days in the hospital. One in 10 dies, usually because delays in closing perforations allow colon contents to leak into the abdominal cavity, causing deadly conditions such as peritonitis and sepsis.
Now, however, in a series of animal studies, researchers at the University of Texas Medical Branch at Galveston (UTMB) have developed a technique for closing perforations promptly after they are recognized by using clips or sutures that can be inserted through the anus via endoscope, thus avoiding invasive surgery. Similar clips and sutures have been used for some time by surgeons performing minimally invasive laparoscopic procedures -- including several gynecological operations and other procedures such as gall bladder removal.
At the annual meeting of the American Society of Gastrointestinal Endoscopy, UTMB professor G.S. Raju, the principal investigator for the wound-repair studies, presented a summary of his experimental endoscopic research over the last three years.
Working with pigs as an experimental model, Raju and his team first successfully closed colon perforations of less than one inch with small metal clips inserted via endoscopes.
During colonoscopies, surgeons accidentally may cause two principal types of perforations, Raju explained. One results from over-stretching the colon, the other from removal of polyps. (Incomplete removal of polyps may cause adhesions, in which the remaining portion of the polyp sticks to the colon wall.) "We have shown in a series of experiments that both types of perforations can be closed successfully using an endoscope without the need for invasive surgery," Raju reported. He added: "We have even accomplished a leak-proof seal of the perforation."
Encouraged by the preliminary work done at UTMB, InScope, a branch of Ethicon Endosurgical of Cincinnati, invited Raju to initiate and lead a multi-center animal study comparing surgical closure with endoscopic efforts to close a gaping, 1.6-inch-wide colon perforation using new clips and sutures. Other institutions joining in the multi-center trial included academic medical centers at Dartmouth University and the University of Cincinnati, and at medical schools in Great Britain and Sweden. "The results are encouraging," Raju said: "As good as surgery in closing perforations, better than surgery in reducing adhesions."
"Experience gained from laboratory experiments was quickly used to improve patient care at UTMB," Raju noted. "Recently, two patients who were not good candidates for surgery were successfully treated at UTMB for postoperative leaks following esophageal and colon cancer surgery using the clip technology."
Raju said he expects that by next year, experience gained in the laboratory will allow his UTMB surgical colleagues Drs. Guillermo Gomez and William Nealon to help patients with gastrointestinal perforations and postoperative leaks. In addition, he said those surgeons hope to explore the role of endoscopy in treating patients with gastrointestinal tumors. He predicts that the minimally invasive endoscopic procedures will help such patients experience less pain, faster healing, less hospital time and lower medical costs, as is the case with laparoscopic procedures.
As for colon wound repair, Raju said if human clinical trials are as successful as those done in pigs, he would expect these procedures to be commonly adopted in hospitals in the near future.
Raju said the UTMB Center for Endoscopic Research, Training and Innovation, (CERTAIN), which he directs, plans to develop courses to train physician colleagues in the region in how to use clips and sutures to close perforations.
Acknowledging the support and guidance of Dr. Jay Pasricha, who served as his research mentor, Raju called the wound-plugging research "a team effort" by colleagues and staff at UTMB.
Raju particularly credited endoscopy research fellow Dr. Ijaz Ahmed for assisting in all the research at UTMB, and The Sealy & Smith Foundation, which donated $3 million to UTMB to expand its endoscopy facilities. Raju also cited support from Pentax Medical, Inc., for equipping the CERTAIN experimental endoscopy laboratory.
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