Axsis is a new robotic surgeon – dexterous but delicate enough to perform cataract surgery. Just 1.8 millimetres in diameter, its two tiny robotic arms would eventually be tipped with surgical instruments. The surgeon teleoperates it using two haptic joysticks, giving instant feedback to the user. Sensing algorithms minimise the risk of human error.
“You can see where the robot is, see where the lens is, see where the relevant anatomy is. And by having a computer in the loop between when the surgeon’s moving their hands and the robot moving, that computer can recognise when the surgeon’s about to make a motion that can go outside and actually puncture the lens, for example, and stop that motion“, says Chris Wagner, Head of Advanced Surgical Systems at Cambridge Consultants.
Traditional surgical robots, such as Intuitive Surgical’s da Vinci system, are large. But Axsis has all components built into a small external body. Inside, tendon-like cables control precise movements; each cable just 110 microns in diameter.
“...the same size as a human hair. And yet this material is gel-spun polyethylene which is stronger than kevlar, stronger than steel by volume and it’s what Nasa uses in some of their solar sails. So it’s an extremely efficient material, extremely strong for making this high performance actuator“, adds Wagner. Routine cataract surgery can already be performed quickly and with a relatively low complication rate. Some ophthalmologists have questioned whether this device offers much improvement. But the makers say Axsis demonstrates how miniaturised robotics could help surgeons with numerous precision procedures, without the barrier of large equipment.
“I think the fact that it’s a 1.8 millimetre diameter robot that’s operating on the size scale of the eye, it’s exciting. This just opens the door to a number of different types of procedures that you can do that previously weren’t possible.” The team says it will still take significant investment and several years to turn this prototype into a viable tool. But, they say, Axsis demonstrates how scaled-down surgical robots could be a cut above the rest.