Robotic surgical assistants, such as the da Vinci systems from Intuitive Surgical, are now routinely used during laparoscopic procedures to improve operative precision, flexibility, and to manipulate multiple tools at once. Such devices can be quite complex inside and so they tend to be quite large, often taking up much of the space of an operating room. Moreover, they are still too cumbersome to operate on particularly fragile tissues and smaller anatomical structures.
Now, a pair of researchers from Harvard’s Wyss Institute and Sony Corporation have come up with a tiny robotic surgical assistant that’s as light as a coin, but that can be used to perform very precise surgical tasks.
Made using a technique called Pop-Up MEMS, which involves bonding layers of materials so that they can open up from their flat starting shape into more complex structures, and piezoelectric materials, the miniature remote center of motion manipulator (the ‘mini-RCM’) can move with impressive precision. Because the manufacturing technique is rather simple and doesn’t involve bringing together tiny parts, the mini-RCM can be mass produced much cheaper than conventional micromechanical devices. Being small, only about the size of a tennis ball, the new device is also easy to install and remove.
The researchers tested the new robotic surgical manipulator by connecting it to a Phantom Omni, a haptic controller made by Sensable Technologies, and had people perform a tracing task with and without its help. When using the mini-RCM, volunteers had 68% fewer errors when tracing out a tiny square on paper. Subsequently, the researchers also used their device to perform mock retinal vein cannulations on synthetic vessels that are about twice the thickness of human hair. They were able to accurately puncture these vessels consistently without causing damage outside the target area, something that eye surgeons will find quite impressive.
The precision is possible because of optical sensors that constantly monitor the motion of the robot and adjust it to maintain consistency, even compensating for random hand tremors that can throw off an otherwise steady hand.