The extremely small surgical tools placed at the working end of the da Vinci robot—the best known robotic surgical system available today, which was approved by the FDA in 2000—are used for minimally invasive procedures. These tiny instruments were designed using origami folding techniques by a group of researchers at Brigham Young University (BYU) in Provo, Utah. We spoke with one of them, Dr. Larry L. Howell, past chair of the Department of Mechanical Engineering.
ME e-mag: First, what does the da Vinci robot bring to minimally invasive surgery?
Dr. Howell: The da Vinci robot is controlled by a surgeon. The surgeon is seated at a computer console near the operating table, and he or she can see the operating site through stereo optics on the console. With his hands, he controls the whole motion of the robot. He can see inside the body because there is a camera attached to the robot.
One of the nice things with the da Vinci is that it gives higher precision and can do a lot of smaller things by itself. Also, when surgeons get older, sometimes they get a little bit of shake in their hands. The robot can filter that out, so experienced surgeons could possibly work longer.
ME e-mag: What are the advantages of minimally invasive surgery?
Dr. Howell: Those procedures allow less time in the hospital, shorter recovery times, reduced chances of infection and scarring. There is a goal that in the future the size of the instruments will be so small that the body would heal with no scar at all.
ME e-mag: How did you decide to use the origami concept to create those tiny instruments?
Dr. Larry Howell: We have been working on the original concept of origami to make things very compact and very flat for years. We also have been working on medical devices and we realized that we may have the possibility of making very small surgical instruments that could go through very small incisions in the body and do complex, mechanical tasks. So surgical robots were a good fit. Taking inspiration from origami-type folding and also compliant mechanisms—a device that gets its motion from bending and deflection instead of hinges and bearings—we put all those things together and it helped us to make surgical instruments smaller than what was possible in the past.
We’ve done similar things with space applications. Imagine a big array of solar panels. We put those together and fold them in a very compact space so we can launch them in space. Once they get into space they expand out to be a large group of solar panels.
That’s the basic idea of our research, from very large things like solar panels to very small things like surgical instruments. We’ve been working with Intuitive Surgical which produces the da Vinci robot for a couple of years now, and also with NASA for space applications.
ME e-mag: Are the tools you create placed directly at the end of the da Vinci arms?
Dr. Howell: On the da Vinci, we created the thing right at the very tip. It’s called the end effector. It goes into the body and is the thing that will be doing the actual surgery. The company already has the robot and everything else, but for different kinds of surgeries you need different surgical tools at the end of the robot.
The instruments we create basically act as medical forceps, to grip things, pull things or cut things depending on how sharp you make the end. They tend to be about 3 millimeters in diameter. We also make some at 5 millimeters and some at 8 millimeters. It’s about half the size of regular instruments.
ME e-mag: What kind of materials do you use?
Dr. Howell: We use 3D printing. Materials are usually stainless steel or titanium because they need to be biocompatible, so you can put them in the body and not have the body react.
ME e-mag: Why do you use 3D printing?
Dr. Howell: We use 3D printing because at the early design stages it’s much quicker to prototype that way. Especially in the early phases of design, development and testing, 3D printing is very good. And the new method called Micro 3D printing made it possible for us to get very high resolution and not have to assemble different parts and not have to machine all the individual features. We can get those just through the 3D printing. Otherwise it would be much more expensive.
We have a 3D printer at BYU but not for the final prototype because it takes some very specialized equipment. That was contracted out to 3D specialists in Europe.