Written for Scars1 by Allison Walker-Elders
The National Institutes of Health (NIH) set aside $2.7 million for a four-year study at Rensselaer Polytechnic Institute. The novel focus of this study concerns the move from animal testing to computer simulation-based “scarless” surgery on the abdominal cavity. Specifically, this is the first ever project to develop a virtual-reality simulator for the practice of endoscopic surgery.
Currently, the only studies conducted in “scarless” endoscopic surgery use animal models. This funding program will enable scientists to develop a simulator to imitate a human patient model. The surgical practice in question is known as natural orifice translumenal endoscopic surgery, or NOTES. In NOTES, a pliable endoscope is inserted into a natural orifice, such as the mouth or the anus. The endoscope allows surgeons to make a small internal incision. A number of procedures can be conducted this way, ranging from appendectomies to gastrointestinal surgery.
Professor Suvranu De, who is leading this study at Rensselaer, says that the computer-based modeling and simulation programs will benefit NOTES greatly. "NOTES is a revolutionary surgical paradigm that is viewed as a natural convergence of diagnostic endoscopy and minimally invasive surgical procedures," said De. Currently, animal testing has been the only method used for developing NOTES. Animal testing is both costly and time-consuming, with the added hindrance of obvious anatomical differences between human patients and animal test subjects.
The benefits to this procedure are numerous. It will eliminate external scarring, reduce pain, and minimize the risk of infection. However, doctors warn that endoscopic surgery is not a magic cure. The procedures are generally minimally invasive, which means that the surgery is less physically and emotionally traumatic to the patient. While NOTES qualifies as “minimally invasive”, it remains a surgical procedure. According to Dr. Marshall Schwartz, a professor of surgery in pediatrics at St. Christopher's Hospital for Children in Philadelphia, patients often believe that “minimally invasive surgery is not painful or that it's not really surgery. Neither is true. It's not Star Trek technology, where we wave a wand over someone and they're healed."
Current Endoscopic Procedures
Esophago Gastro Duodenoscopy (EGD)
ERCP - Endoscopic Retrograde Cholangiopancreatography
Minimally invasive as NOTES may be, a basic knowledge of the procedure confirms Dr. Schwartz’s statement. Surgeons insert miniscule surgical tools through the endoscope. The instruments enter the abdominal cavity by making an incision in wall of the viscera. This can take place in the stomach, vagina, colon, or other internal organs. The surgeons use the instruments to perform the necessary medical procedure and then withdraw via the endoscope, finally sealing the incision and removing the endoscope. Currently, animal testing is the only medium used to practice these techniques. Unfortunately, many post-operative complications and procedural roadblocks have impeded progress.
To perfect the techniques practiced with endoscopic surgery, as well as to expand the scope of NOTES to other procedures, De and his interdisciplinary research team will develop a virtual reality simulator. This implement will utilize robotic interfaces and touch-sensitive surfaces to mimic the experience of performing surgery on a live human patient. A monitor will display realistic computer-generated models, and manual controls will allow surgeons to practice using endoscopic instruments. Most impressive among the features of this simulation is the haptic touch-feedback system, which will provide the tactile experience of surgery. It will imitate living tissue, providing malleable sponginess and resistance for users.
"The aim of this study is to overcome these preliminary challenges, and develop the first virtual reality NOTES simulator that is firmly based on physical experiments and surgical experience," said Professor De. "The simulator must also be realistically responsive to physiological consequences of surgical complications.” The team is already planning the first simulated procedure, an appendectomy.
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Photo Source: Julien Haler