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Home U Rising The Utah Bionic Leg: Empowering people to walk, climb and to do so much more


U Researcher Tommaso Lenzi says the technology behind current prosthetic devices is decades old. That’s why he and his collaborators are so excited about the Utah Bionic Leg, which uses motors and sensors to power movement just like muscles do. U Rising Host Julie Kiefer talks with Lenzi, an associate professor in the U’s Department of Mechanical Engineering and director of the HGN Lab for Bionic Engineering, about this new prosthetic, which could someday benefit millions. including people who experience amputations below or above the knee.

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Julie Kiefer: Welcome to U Rising, where we share stories about interesting and often groundbreaking research and innovations taking place at the University of Utah.

I'm Julie Keffer, associate director of science communications at University of Utah Health and host of this episode.

My guest today is Tommaso Lenzi. Tommaso is an associate professor in the U’s Department of Mechanical Engineering. He's also the director of the ergonomics and safety program in the Rocky Mountain Center for Occupational and Environmental Health and he directs the HGN Lab for Bionic Engineering.

Today we're going to talk to Professor Lenzi about a powered exoskeleton, specifically a bionic leg that his team designed and developed. This is the stuff of science fiction and I'm excited to learn more.

Welcome to U Rising, Tommaso!

Tommaso Lenzi: Thank you. I'm excited to be here.

Julie Kiefer: So, you direct the HGN Lab for Bionic Engineering. Does HGN stand for something and what exactly is bionic engineering?

Tommaso Lenzi: So bionic engineering is the science of engineering artificial systems that work like living organisms or parts of living organisms. And at the bionic engineering lab, we are particularly interested in bionic legs.

So, we are developing artificial legs, robotic legs, that work like human legs. And we are particularly interested in bionic leg prosthesis, which is the kind of device that a person with an amputation below or above the knee level would use. And also bionic exoskeletons. These are the kind of devices that could help people that still have their biological legs, but maybe they lost strength or control due to trauma or injury.

And ultimately what we envision is really a world where acquired or congenital body differences will not impair people and not prevent them to achieve their life goals and do whatever they want to do. And we really feel that bionics can help them achieving these goals, the key to empowering people to have the mobility they need and achieve their life goals.

Julie Kiefer: It's so important to be able to meet that need. And what does HGN stand for?

Tommaso Lenzi: So, HGN is the initials of Hans Georg Näder, who's the chairman and founder of Ottobock, the largest prosthetics company in the world. And Professor Näder sponsored our lab and gave us this naming donation to really enable us to buy equipment and instruments for the lab with all the tools that we need to achieve our goals and pursue our research.

       Tommaso Lenzi

Julie Kiefer: And how many people could this potentially benefit?

Tommaso Lenzi: So, there are approximately 1 million Americans living with amputation and the number is expected to double by 2050 due to the prevalence of peripheral vascular disease, which is a complication of diabetes. But when you look at the number of people that are actually struggling with mobility, so walking or simple activities like climbing a few steps, that's much greater. The CDC estimates there are about 30 million Americans struggling with simple tasks, again, like walking or climbing a few steps. It's pretty much like one in 10 people.

Julie Kiefer: So your research is really seeking to fill a very important need. What got you interested in this type of work?

Tommaso Lenzi: Yeah, it, it's a little bit of a long story and, for me, I wanted to be an engineer since I was a little kid and so being a major in college was no-brainer. But when I was in college, I got interested in medical devices but I didn't really feel quite ready. So, I decided to do a master in biomedical engineering and then a Ph.D. in robotics.

And then at that time, I felt like, okay, now I have all the knowledge that I need, but I felt like I was really missing a purpose. And so I started thinking about the role of engineering in society and, you know, I really feel like at the core, engineers are problem solvers and tens of millions of people are living with physical disability. I couldn't really think of a better problem, more important problem, to solve than empowering people to live independently. And so I decided to pursue this field and to use my knowledge in robotics and bionics to develop assistive technologies that can help people be independent.

Julie Kiefer: And you're making some great strides in this goal. Recently the Utah Bionic Leg was featured on the cover of a prestigious scientific journal, Science Robotics. This leg is a powered exoskeleton for lower limb amputees. Can you tell us a little bit about this leg and how it's different from other prosthetics?

Tommaso Lenzi: Yeah. So, unfortunately, you know, we are not doing great with prosthetics and so people are kind of surprised when I say this, but if you were to have an amputation today, you'd be given a technology that is fundamentally 50, 60, even 70 years old, and that's the best-case scenario.

So these prostheses that are available on the market are basically designed to keep you up and not so much more. They are passive, they cannot move like a biological leg can. And so there's a really difficult process of relearning to walk and you have to compensate so hard with your body that everything becomes so challenging. So, most amputees can only walk half the speed that they could walk before amputation and they probably expand twice as much energy. And also falls are quite frequent. And so fear of falling is a big factor.

And, this really leads to secondary complications. Depression is very common, again, because of the lack of mobility, but also osteoarthritis, back pain, are very common. Again, think about you're missing a leg and you're using the rest of your body to compensate for the weakness of this prosthesis that you're given.

And so our device is completely different from these prostheses that are available on the market.  The Utah Bionic Leg has motors and sensors and controls. And what this can do is these motors can pretty much generate power, like your muscles can, and can control the movements like your leg can. And so what we are trying to do with our research is to combine these new mechanisms and technologies with more advanced controls and AI so that the artificial leg, this robotic leg prosthesis, can behave like your missing biological leg.

So something that is kind of also interesting is that, you know, this idea of putting motors in a prosthesis is not new, right, people have been trying for at least 25 years. But so far everyone has failed because the resulting device, these motorized prostheses, were just too heavy, too inefficient and loud to really be used in everyday life. People just don't want them.

And here at Utah, what we did is we achieved a breakthrough in actuation technologies. And so our robotic leg prosthesis, the Utah Bionic Leg, is much, much lighter and more efficient than any other motorized prosthesis. And, in fact, when you look at the power and torque density, so the ability to generate power, it's actually exceeding what the biological leg can do.

Julie Kiefer: Yeah, I wanted to ask you about that. So could you use these legs to give people abilities that maybe they didn't even have before, like to run faster or jump higher or it's like the $6 Million Man, if you think of that 1970s TV show, for anyone who may have heard about that. That's what I thought of right away! In that show, this man had bionic legs and arms and an eye and could do these super-human things.

Is that sort of thing possible or maybe not to that extreme, you know, but could you have a heightened ability compared to what you had before?

Tommaso Lenzi: Yeah, I think that improving or augmenting human mobility is definitely possible. And it is something that is interesting. But at the same time, in our lab we are really trying to stay focused on mobility and disability and really trying to use technology to empower people to do what they want to do. And something that strikes me is that when we think about disability it really, for many people, feels like a binary thing where either you are able or you are disabled and I don't think that's true at all. I feel like when you think about mobility or ability, generally, you know, you see this lives in a spectrum, right? And you can move up and down the spectrum of mobility, right? For example, as you age, you do lose strength and endurance and technology can definitely enable you to go up on this spectrum mobility, enable you to do more and maybe walk faster, run faster.

But the way I like to think about the technologies that we build is that we want you to be able to get, we want people to get to the level of mobility they need and they want to pursue their life goals. And so for some people, yes, being able to go and hike for hours is important. Maybe they're young, they're active, they want that kind of lifestyle. For other people, maybe they're older, all they want is to be able to go in the park and walk with their grandchildren. And so really these, I feel like there's a lot of like personal differences that we need to take into account when we think about empowering people and augmenting their mobility.

Julie Kiefer: And so for the people who take part in your research, who have an amputated leg and maybe haven't had their own leg for years, I mean, what's the experience like for them to put on this bionic leg for the first time and try it out?

Tommaso Lenzi: Yeah, that's one of the most exciting and, you know, rewarding experiences and parts of my job I'll say. And you know, don't get me wrong, we are still in this research phase. It's not like every single experiment is perfect, but more and more often we feel like we put this bionic leg on and you see these people walking around the lab, being able to climb stairs up and down, go down ramps, do everything so naturally, it just really feels like magic. It is special.

There's also like an emotional part related to this that I feel like it's very powerful. Think about you had an amputation maybe 10 or 15 years ago and since then you've never been able to climb stairs and now suddenly you're in this lab and, you know, me and my colleagues, my students are now telling you, okay, now just go climb stairs, right? And you haven't done it for 10 or 15 years. And so there's definitely like an emotional component about, you know, seeing these people being able to do things that they are not able and they have almost kind of given up on, right? And so that's always like an interesting part and it's always like a very powerful part of our research.

Julie Kiefer: I'm sure it makes the work very satisfying.

Tommaso Lenzi: Yeah. It definitely does. And also, you know, I think when we think about mobility, there's some like practical aspect about it, right? Like if you're unable to climb stairs or deal with some obstacles, you maybe are not likely to do your life the same way and so definitely we think about that. But also there's something more fundamental. I think just being able to know that you can do something or possibly you can do everything you want to do, this really is the key. It's not so much if you need it or not, if you need to be able to do this certain activity, but knowing that now you can really makes you feel like you don't have a limitation and you don't have a burden that you have to carry on your daily life.

Julie Kiefer: And there's so much that goes into all of this. You need to research, do research, to figure out what needs to be done. You need to develop the technology, build the technology, test it, make sure that it actually works for the patient or for the person who's using it. Can you talk a little bit about the collaborations that go into this project and who you're working with?

Tommaso Lenzi: Yeah, so you know, Utah has a such a long history of biomedical breakthroughs and we are inspired by our past. You know, the first bionic arm was developed here at University of Utah in the ’70s by Stephen Jacobsen. And so really we are standing on the shoulders of these giants. And the whole environment that I found here is very collaborative and as you said, there's a lot that goes into this.

Robotics is one of the core disciplines that we put in this, but there's physical therapy, there's biomechanics, there's medicine. And here at Utah, I was able to find all the collaborators and experts that I need. And so for example, we work with the director of the amputee clinic, Colby Hansen at the Nielsen Rehabilitation Hospital and so he is our primary clinician. We work with is Dr. Bo Foreman in physical therapy. He's our biomechanics expert. And we work with Spencer Thompson. He's another physical therapist in the U of U Health Sugar House facility that does most of the amputee rehabilitation right after surgery, pretty much.

And the other thing that we have is an incredible amputee community around here. There really is a sense of community and a sense of wanting to help each other. And I think this is essential because I really wouldn't be able to do what I do without these study participants. And, you know, some of these people we've worked with for five, six years now, almost seeing them every week.It's almost like they become collaborators, right? Their input, their feedback, on what works, what doesn't work, is an essential part of our research and development.

Julie Kiefer: So, you've reached some important milestones and a future step, important step, along this journey, will be FDA approval. Where are you along this process?

Tommaso Lenzi: Yeah, so we are collecting the data and we are doing the studies, the clinical studies, that are going to support future FDA approval. And so, we are lucky to have support from the National Institutes of Health and the Department of Defense to conduct these clinical studies. And so now I think we're building the foundations for what the future FDA approval will be so demonstrating that this is not only possible, but it's safe and it's actually effective. So, it's very difficult to demonstrate that these devices ultimately empower people to have better mobility. And that's because we have to have a significant number of subjects involved in our studies and we need to conduct these studies in a way that is conducive to demonstrate the proper outcomes.

Julie Kiefer: And is there commercial interest in the product?

Tommaso Lenzi: Yeah, so we recently partnered with Ottobock, who is the largest and oldest company in prosthetics and orthotics. And they have acquired the license to of the Utah Bionic Leg for commercialization. And also they provided a contract to my lab. So, what's going on right now is that the engineers in my lab and the grad students in my lab are working with the engineers in the R& D of Ottobock, which is located in Germany and in Austria. And, together we are taking the next steps in the project, which is really going through the redesign of the device, of a new generation of the Utah Bionic Leg, that would be able to go through the level of certification and rigorous testing that is necessary to become an actual product. The goal is to try and bring the device to the market so that it can actually help people.

Julie Kiefer: And when do you think that might happen?

Tommaso Lenzi: Yeah, it's always hard …

Julie Kiefer: I know that's a tricky question, isn't it?

Tommaso Lenzi: Yeah, it's tricky, especially because of expectations and it really depends on how these clinical tests are going to go, but it could be as soon as three years. So, the time window that we're thinking about could be anywhere between three to five years, and it may seem like a long time, but the time that is required for certifications and to make sure that the manufacturing is right and everything is done correctly is quite a substantial effort. And so I think that's more or less a timeline that we're going to need.

Julie Kiefer: And what is your vision about where this might be heading, say 10 or 20 years down the road?

Tommaso Lenzi: You know, I think we are living in such a special time because of the impact that we're going to see of bionics and AI and robotics in everyday life. And for me, this is so powerful and obvious because, you know, when I was a grad student about 10, 15 years ago, when I started, people didn't even believe that this could happen, right? The question was like, ‘Are we ever going to have a robotic leg that looks like a human leg again?’ And now we do, right? And now we're after the next question, which is like, okay, how do we put it out there? How do we bring this technology to the tens of millions of people living with mobility, disability? And so, I think that's what's going to happen in 10, the next 10, 15 years.

Julie Kiefer: Well, Tommaso, this is really exciting work and I look forward to hearing more in the future. Thanks so much for being my guest on U Rising.

Tommaso Lenzi: Thank you for having me.

Julie Kiefer: Listeners, that's it for today's episode of U Rising. Our executive producer is Brooke Adams and our technical producer is Robert Nelson.

I hope you'll tune in next week when my co-host Chris Nelson will be talking with Rodney Cohen about the U'S HBCU Partnership Program. I'm Julie Kiefer, thanks for listening.