A sophisticated new surgical technology holds promise for future painless and scarless surgery with shorter recovery times than laparoscopic surgery. New research supporting the safety and efficacy of natural orifice translumenal endoscopic surgery (NOTESTM) and detailing the outcomes associated with new tools and robotic applications will be presented today at Digestive Disease Week® 2008 (DDW®). DDW is the largest international gathering of physicians and researchers in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.
“The research developments presented today are continuing to demonstrate the great potential of this exciting new surgical procedure,” said Pankaj J. Pasricha, MD, FASGE, professor of medicine, gastroenterology and hepatology, Stanford University School of Medicine. “Surgical advances like NOTES may lead the way toward the adoption of even more minimally invasive techniques than laparoscopy and allow patients to return to their home, family and work more quickly.”
NOTES is performed by passing an endoscope through a natural orifice then through an internal incision in the stomach, vagina, bladder or colon, thus avoiding any external incisions or scars.
A Prospective Randomized Controlled Trial of NOTES versus Laparoscopic Distal Pancreatectomy, Preliminary Results (Abstract #881)
Investigators have conducted the largest and most rigorously controlled study of natural orifice surgery to date. The study showed that while NOTESTM is more time-consuming than traditional (laparoscopic) surgery, it is equally successful. The study also demonstrated that complex surgery with a high rate of complications could be performed via the mouth using a flexible endoscope.
“NOTES is an area of promise in active development,” said Field Willingham, MD, MPH, senior fellow in the gastrointestinal unit at Massachusetts General Hospital. “The opportunities with NOTES are significant and should some day provide patients with a viable scarless and painless option for certain medical procedures.”
Previous NOTES research has involved small sample sizes and no control groups. This prospective, randomized controlled trial compared the efficacy of endoscopic transgastric distal pancreatectomy (ETDP) to laproscopic distal pancreatectomy (LDP). Investigators randomized twenty-eight 45kg swine to EDTP or LDP and then compared the results based on an extensive post-operative analysis. The procedure time for EDTP was significantly greater versus LDP (1:52 versus 0:32 hour), but investigators found no clinical or survival difference between the NOTES and laparoscopic approaches.
Dr. Willingham noted that the tools used to dissect or retract during NOTES procedures may pose some limitations. “It can be challenging to perform complex procedures such as holding traction while simultaneously dissecting tissue through a single NOTES endoscope.” However, this study does demonstrate the non-inferiority of NOTES in solid organ resection compared to standard laparoscopic surgery.
Successful Diagnostic and Therapeutic Intrauterine Fetal Interventions by NOTES (Abstract #871)
Investigators using NOTESTM have found for the first time that it can look at the entire uterus and reach areas that had not previously been accessible. The findings are important because the morbidity and mortality of fetal surgery is substantial.
If the fetus requires lifesaving surgery, the only way to operate previously was through traditional laparoscopy or laparotomy. But this method is limiting because the uterus and the fetus can only be accessed from the front; unless a doctor is aiming to intervene right beneath the abdominal wall, it would be difficult to access the desired organ. However, using flexible endoscopy, doctors can reach almost any part of the uterus, regardless of the direction the fetus is facing. Furthermore, the procedure could be particularly helpful since it provides a minimally invasive approach to performing fetal surgery.
Researchers performed transgastric peritonoscopy on one ewe and transvaginal peritonoscopy on another following standard needle-knife entry into the abdominal cavity. Access to the uterus was assessed with both a forward-viewing endoscope and a linear-array echoendoscope. Visibility of the fetal areas via endoscopic ultrasound (EUS) was directly compared to transabdominal ultrasound. EUS-guided, transuterine injection of saline into the fetal cardiac ventricle was attempted in both sheep using a 22-gauge fine needle aspiration needle.
Investigators found that access to and complete visualization of the uterus were successful with both endoscopes using an anterior, posterior and lateral approach once inside the abdominal cavity. Also, visualization of the fetal parts by EUS was impressive and superior to transabdominal ultrasound.
“Our findings suggest that NOTES may provide an avenue through which one can ultimately stage even more complicated operations in pregnant women and the fetus,” said Samuel A. Giday, MD, assistant professor of medicine at Johns Hopkins University School of Medicine division of gastroenterology and hepatology.
Randomized Multicenter Controlled Study of Endoscopic and Surgical Closure of A Gastric NOTES Access Perforation in a Porcine Model (Abstract #876)
Researchers studying endoscopically sutured closure of a gastric access perforation using a T-tag tissue apposition system (TAS) compared to conventional surgical closure found that gastric NOTESTM access perforations can be safely and reliably closed using TAS. TAS is designed to suture via flexible endoscopes. It places a tilt T-tag attached to a thread into tissue using a small diameter flexible needle. Two or more threads can then be locked together using a thread locking device. All the components can be passed through a conventional (2.8 mm) accessory channel of a flexible gastroscope without requiring withdrawal of the endoscope.
Unlike other suturing devices, it does not require loading onto the endoscope before use, it is much smaller in diameter, and it does not interfere with endoscope flexibility or function. The needle can be placed under direct vision with great accuracy and is intuitively easy to use.
In a randomized, multi-center study of 30 pigs, investigators measured procedure time, recovery time and weight gain at days seven and 14. The study found that closure time using the endoscopic NOTES technique was significantly longer than with open surgery. However, researchers found that at necropsy on day 14, there were significantly more intra-abdominal adhesions (internal scarring sticking internal organs together) in the surgical group, mainly between the stomach, liver and abdominal wall.
Concerns about efficacy and consequent safety of closure, especially of the stomach approach, are important if the potential benefits of a NOTES approach are to be realized. If the method can be as safe as a surgical closure and reduce adhesion formation then this will encourage further research in this field. Adhesions can cause abdominal pain and obstruction, very occasionally requiring surgery. Transgastric surgery as a NOTES access approach is in general more attractive than transvaginal or transrectal approaches, provided closure can be shown to be safe and effective.
Recovery time following the procedure was the same in both groups, and there was no difference in post-operative weight gain between the groups. Also, a gastric NOTES access perforation can be safely closed endoscopically using TAS sutures and clips. Lastly, researchers found that animals in the endoscopic group had significantly fewer lesions at autopsy, and recovered more quickly post-operatively, compared with open surgery.
“Because the TAS system allows access to small and remote areas, and results in less scarring than open surgery closures, it may be the key to expanding the use of the NOTES procedure,” said Paul Swain, MD, of the department of technology and medicine at the Imperial College of Science in London.
Robotics and NOTES: A Good Marriage or Just Hype? (Abstract #Sp535)
Incisionless surgery using robotic technology, in which surgeons work exclusively through the mouth or other openings, showed excellent results in a recent study. The approach is important for three reasons: first, it allows patients to undergo procedures without pain and scarring; second, the procedure is performed on an outpatient basis; and third, the robotic technology enables doctors to perform procedures in ways they would not otherwise be able to do.
Researchers used a small robotic device to perform more than 25 procedures in five animals – including abdominal exploration, bowel manipulation, cholecystectomy, and intracorporeal suturing, partial splenectomy and liver resection – without making cuts to the abdomen. The devices, which are the size of two lipstick tubes, have a central body, two working arms and a built-in light source. Researchers obtained standard transgastric access, and then passed a 22-millimeter overtube past the gastrotomy. They then inserted several miniature robots to perform the operations.
Each procedure was accomplished with at least two robots and endoscopic assistance. Researchers found that visualization of the operative field was superior to endoscopic manipulation alone because it offered more opportunities for use.
“Currently there are a number of endoscopic tools for taking out polyps” said Dmitry Oleynikov, MD, director of minimally invasive surgery at the University of Nebraska Medical Center. “But this technology can do much more, and it can do it more efficiently.” For example, the robotic device could be used to remove portions of the colon that had cancer, it could remove the spleen, or it could repair a hernia.
Dr. Oleynikov said that while the device showed promising results in this study, it has limitations. For example, while its small size allows it to reach areas that other devices cannot, the device is not large enough to move around larger organs, so more research will have to be done to make it more robust, especially for human use. He said it is possible that with successful FDA trials, the technology could be available for human use any time from 18 months to three years from today.
Digestive Disease Week® 2008 (DDW®) is the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery. Jointly sponsored by the American Association for the Study of Liver Diseases (AASLD), the American Gastroenterological Association (AGA) Institute, the American Society for Gastrointestinal Endoscopy (ASGE) and the Society for Surgery of the Alimentary Tract (SSAT), DDW takes place May 17-22, 2008 in San Diego, Calif. The meeting showcases more than 5,000 abstracts and hundreds of lectures on the latest advances in GI research, medicine and technology.
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