Magnets: The future of endoscopy

From the Summer 2017 edition of Vanderbilt Medicine Magazine

You’ve turned 50. Happy birthday; it’s time to start screening for colorectal cancer.

For some people, the colonoscopy—a procedure in which an endoscopist uses a long, flexible tube with a camera at the tip to examine the inside of the colon—brings feelings of dread.

“Patients may fear colonoscopy, or not be able to take a day off of work to be sedated, or live in a place where they don’t have access to the procedure,” says gastroenterologist Keith Obstein, M.D., MPH, associate professor of Medicine and Mechanical Engineering at Vanderbilt University.

There are risks of adverse events related to sedation or the procedure itself—colon trauma or perforation. These risks increase for people who require more frequent colonoscopies, such as patients who have inflammatory bowel disease.

And although colorectal cancer screening rates ticked up between 2010 and 2015, more than a third of Americans are still not being screened, according to the Centers for Disease Control and Prevention.

Obstein and a team of engineers in the STORM (Science and Technology of Robotics in Medicine) Lab are using the principles of robotics to change the way colonoscopies are performed, with the goal of reducing the risk of adverse events and making the procedure more widely available.

One of the problems with traditional colonoscopy is the way the endoscope is “driven,” Obstein says. The tip with the camera, connected to flexible tubing, is inserted at the anus and pushed forward from outside the body. The pushing can cause looping of the tubing, which stretches the colon and can be uncomfortable—and is why most people have sedation for the procedure.

The STORM Lab team has built a magnetic flexible endoscope that is driven from the front, using magnetics. The endoscope head contains the camera, magnet and channels for therapeutic devices such as biopsy forceps or polypectomy loops. A robotic arm that is external to the patient holds an actuating magnet and moves the capsule head forward by magnetic coupling with the endoscope, thus pulling the tubing behind it, using algorithms developed by the group.

“We’re able to essentially tell the robotic arm how to manipulate the external actuating magnet in order to maneuver the capsule,” Obstein says.

The team has automated a maneuver called retroflexion, where the endoscopist flips the endoscope tip backward. Retroflexion requires technical expertise and normally can only be completed in the wider end sections of the colon. With the magnetic flexible endoscope, however, the retroflexion maneuver can be completed anywhere along the colon at the push of a button, Obstein says. The researchers successfully completed the maneuver 30 times in a living pig colon with no adverse events.

“This is the first example of a completely autonomous maneuver in endoscopy,” Obstein says.

The team is also developing teloperation control for the magnetic endoscope, which may make it possible for an endoscopist to operate the equipment from a remote location with a local technologist present to advance any needed instruments through the endoscope.

“The idea is to have the same diagnostic and therapeutic capabilities as a current endoscope, but to change the dynamics of how it’s driven to reduce looping, possibly mitigate the need for sedation, reduce adverse events and be able to offer the procedure more widely,” Obstein says.

The team is also developing a disposable endoscope with a portable control system for gastric cancer screening in low-income areas of the world where gastric cancer rates are high and a disposable endoscope that can be used “off the shelf” connected to a phone or tablet for rapid bedside upper gastrointestinal endoscopy without sedation.

The STORM Lab is co-directed by Obstein and Pietro Valdastri, Ph.D., adjunct professor of Mechanical Engineering at Vanderbilt and now based at the University of Leeds.