A capsule robot just took its maiden voyage - through a pig's colon

Guided by magnets

Colonoscopies are not the most pleasant of experiences. Doctors use a thin, flexible tube to examine the inside of your large intestine and look for ulcers, polyps and other signs of cancer.  It's uncomfortable at best, and painful at worst.

But biomedical engineers from Vanderbilt University's Medical Centre in Nashville believe that they've developed a better solution. They've built an autonomous 'capsule robot' that uses magnets to traverse the inside of a colon.

There are two components. The first is an internal capsule that has a camera and a 'tail' that lets doctors control tools attached to it. The second is a robotic arm which moves around above the body, not touching the skin but guiding the internal capsule where it needs to go. Pulling, rather than pushing, the colonoscope means it's less likely to get stuck on protrusions. 

"Since the external magnet pulls the capsule robot with the tether segment from the front or head of the capsule, instead of a physician pushing the colonoscope from behind as in traditional endoscopy, we're able to avoid much of the physical pressure that is placed on the patient's colon - possibly reducing the need for sedation or pain medication," said Keith Obstein, corresponding author on a paper describing the technology (which has not yet been peer-reviewed).

Reverse view

The team also programmed the arm to perform a manoeuvre called a 'retroflexion', where the colonoscope turns around to get a reverse view. In testing on pigs, the machine successfully performed a retroflexion 30 times, taking an average of 12 seconds to perform each one.

"Not only is the capsule robot able to actively maneuver through the GI tract to perform diagnostics, it is also able to perform therapeutic maneuvers, such as biopsies of tissue or polyp removal, due to the tether - something that other capsule devices are unable to do," added Obstein, who presented his work at the Digestive Disease Week conference 2017. 

Following the tests on pigs, human trials are expected to begin at the end of 2018. Until then, the team will work on optimising the algorithms that control the colonoscope, improving its manoeuvring performance.