Pietro Valdastri, PhD
Researchers at Vanderbilt University and the University of Leeds in England have successfully performed autonomous retroflexion of a robotic capsule during colonoscopy in a subject animal, according to data presented during Digestive Disease Week 2017 at McCormick Place in Chicago.
Retroflexion is a process whereby the head of the capsule is pivoted 180 degrees to achieve a reverse view of the colon walls.
Pietro Valdastri, PhD, principal technical investigator, said the device being tested was controlled by an external magnetic robotic arm that could pull and maneuver the tethered capsule without causing stress or damage to the walls of the colon. He said the test, performed 30 times in a pig, was 100% successful. “No leaks or histologic abnormalities were visualized on necropsy,” according to a statement from the study’s authors.
The significance of the achievement is that retroflexion to provide a better view of the colon can be performed at any point in the large intestine, painlessly, and without the need to push against a portion of the colon wall to help with the 180 degree turn performed by the instrument.
“With a traditional endoscope, that would not have been possible, because we retroflected at positions where there was no wall to help the retroflection procedure,” Valdastri said in an interview with OncLive
The benefit of greater camera maneuverability includes a higher likelihood of detecting lesions and polyps, especially ones hidden behind haustral folds that can be easily missed by frontal-view colonoscopy.
A traditional procedure with an endoscope is conducted with force applied to the instrument from behind, and involves the use of cable controls that add to the thickness of the device.
“This is the advantage of it being front-wheel driven by magnetic force. We do not stretch the tissue and therefore we do not cause pain. Moving this capsule by magnetic fields, we can reorient it left, right, up, and down, which is currently performed in the flexible endoscope with cables running through the length of the device,” Valdastri said.
The capsule head containing the camera is 2 cm in diameter, which is comparable to the size of an endoscope. The tether to the capsule, which is smaller, consists of a soft tube through which standard instruments can be inserted, so that the device can perform all of the same functions of an endoscope.
“In terms of capabilities, diagnostic and therapeutic, we are at the same level. We have the same type of camera and the same type of intervention of capabilities, because we have an instrument channel through which we can introduce standard endoscopy instruments,” Valdastri said.
Researchers believe the procedure with the robotic capsule could be performed without sedation. This is important in cases where patients cannot be sedated because of their health problems. In addition, Valdastri, said, monetary savings are possible by avoiding the use of anesthesiologists.
Currently, there are no robotic devices available for use in colonoscopy, although there is a system developed in Germany called an invendoscope, which by description is still a flexible endoscope. “The diameter is still large and the instrument is not soft and pliable,” Valdastri said.
The robotic capsule will move on to human trials in 2019 or 2020, with the goal of demonstrating that the device does not harm the patient, he said.
Patients enrolled in the trial would receive both a colonoscopy with the robotic capsule and one with a traditional endoscope, without sedation. The levels of pain will be compared.
Another attraction of using the robotic capsule, is that it makes it possible to perform certain operations without human involvement, such as the retroflexion, which during the current trial was done with a “push of a button.” Valdastri explained that artificial intelligence will 1 day make it possible to automate much of the activity of a colonoscopy and even such procedures as a polypectomy. “Nothing would prevent us from training our system to understand whether we are looking at a lesion or not. That’s in the future—the soon-to-come future.”
In the meantime, there inevitably will be liability issues to resolve and resistance from the gastroenterology community, Valdastri predicted.
The research was conducted initially at Vanderbilt University in Nashville, Tennessee, and has been shifted to the University of Leeds, which is a partner in the effort, Valdastri explained. Funding has been through grant money provided by the National Institutes of Health.
Corporate investors who would be able to help with bringing the product to market will likely wait for the human trial before committing to underwrite the research, Valdastri said. In the meantime, “we are trying to go as far as possible with grant money.”
Sarker S, Slawinski PR, Taddese AZ, et al. The first autonomously controlled capsule robot for colon exploration. Presented at: Digestive Disease Week; May 6-9, 2017; Chicago, Illinois. Abstract Mo1962.