It aims to prevent human errors that sometimes cause complications.
By
Sally Adee

Source:
New Scientist
7 Nov 2016 - 12:33 PM  UPDATED 7 Nov 2016 - 12:33 PM

See what it can do. A new surgical robot can make the micro-scale movements needed for a particularly delicate procedure: cataract surgery.

Axsis, a system developed by Cambridge Consultants, is a small, teleoperated robot with two arms tipped with tiny pincers. It’s designed to operate on the eye with greater accuracy than a human.

Globally, 20 million people have cataract surgery every year, making it one of the most common surgeries in the world. Although complications are very rare, they still affect tens of thousands of people.

Cataracts happen when the natural lens of the eye gets cloudy and obscures vision. To restore a person’s sight, a surgeon cuts a small hole in the lens, scoops out the bit that’s gone cloudy, and replaces it with what’s essentially a permanent plastic contact lens.

The whole thing requires a steady hand, and the most common complication arises when a surgeon accidentally pierces the back of the lens, a thin membrane that is only a few millimetres off target, causing hazy vision.

Axsis aims to prevent this kind of human error. The device’s articulating pincers are mounted on arms about the size of drinks cans, with extremely light, strong “tendons” made of the same material NASA uses for its solar sails. These pincers can sweep across a 10-millimetre space – the size of the lens of the eye. This is just a demonstrations model; in the final product, the pincers will be replaced with scalpels. 

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Robo halo

To control the robot, the surgeon sits at a station nearby and uses two 3D haptic joysticks to move the pincers while watching their work on a screen. The image on the screen is enlarged, so the surgeon can make more precise movements, with the pincers operating at a tiny scale not possible with the human hand.

One benefit of the system is that the software disables certain boundaries from being breached. “It won’t let you make the mistake of punching through the back of the lens,” says Chris Wagner, the lead roboticist on the project.

The robot hands in action (Photo by Axsis/Cambridge Consultants)

We already use surgical robots, such as the Da Vinci system, for some other operations. But these robots are usually quite large, often completely enveloping the patient and using long, telescoping instruments.

“The attachments need to do huge sweeps outside the body to do minute movements inside the patient,” says Wagner. Axsis is scaled down to a small halo around the head. In part thanks to its smaller size, the system will be cheaper than other robotic surgery techniques.

And while other robots have been designed to work at small scales – even on eyes – they have not done cataract surgery. Trials of a robotic system developed by Dutch firm Preceyes Medical Robotics are ongoing at Oxford’s John Radcliffe Hospital and focus on the retina, rather than the lens. 

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First eyes, then guts

Ian Murdoch, an ophthalmologist at University College London, says he is interested in the idea that Axsis prevents piercing the back of the lens. “This happens in about 0.1 to 0.7 per cent of cases,” he says. “If the complication rate is less then this would obviously be great.”

However, Murdoch wonders if Axsis really offers much advantage over existing advanced cataract surgery techniques, such as laser cataract surgery.

Peter Kim, a surgeon at the Children’s National Health System in Washington DC who is working on a larger, autonomous surgical robot,  says that microsurgical robots are already used in some clinical settings, such as the NeuroArm robot used in brain surgery. “I applaud the miniaturisation, but I am not clear on the unmet need and value proposition,” he says.

But Axsis’s creators say that cataract surgery is just the start.  “I think it will quickly find more applications,” says Wagner. It could, for example, be used in gastrointestinal operations. Put the pincer end of Axsis on an endoscope and it could solve any small problems – like removing polyps – then and there. “Nowadays, when you find something in the colon or in the stomach, you leave it there,” says Wagner.

Wagner hopes the robot could one day enable operations surgeons can only dream of. “We just want to push forward what’s possible.” 

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This article was originally published in New Scientist© All Rights reserved. Distributed by Tribune Content Agency.