Director Daria Price recently  interviewed Michael Goldfarb, Director of the Center for Intelligent Mechatronics at Vanderbilt University, Nashville, Tennessee. Featured in OUT ON A LIMB, Goldfarb is a scientist working on the next generation of prosthetics. (See clips of Goldfarb in the film at: http://www.youtube.com/watch?v=k_VBRYWH4EY )

Daria Price: When we were down there a few years ago, we shot Craig Hutto, a young man who had lost his leg to a shark, demonstrating an early prototype of the Vanderbilt leg--the world's first lower extremity prosthesis with actively powered knee and ankle joints that operate synergistically. What makes this leg the first of its kind and how will it benefit amputees in ways that other currently available prosthetics do not?

Michael Goldfarb: As you imply, the leg is unlike others currently available in that is has fully powered knee and ankle joints that work synergistically. This synergism provides benefits in level walking (such as providing improved biomechanics, better symmetry of gait, and lower energy consumption), but probably provides the most significant benefit to the amputee in non-level walking, such as walking up and down slopes and stairs. We have documented improved biomechanics in non-level terrain. We also expect significantly reduced energy consumption in non-level terrain, although we have not yet had the opportunity to document this. Perhaps most significantly, amputees stumble and fall at an extremely high rate (higher than institution-living elderly), and this leg should significantly reduce incidence of stumble and fall. We have recently submitted a proposal to the NIH to formally investigate and document the effect of this leg on the incidence of falls in transfemoral amputees.

DP: It was recently licensed by Freedom Innovations, which is an exciting development.  What do you hope to see happen with this licensing agreement? Any idea when it might become commercially available?

Michael Goldfarb: I’m very excited about the license. It is my intent (and Freedom’s) to make this technology available to amputees throughout the world, and we hope in doing so to improve their mobility and quality of life. Our original intent was to introduce the leg to the market in 2013, but the date could slip into 2014.

DP: You and your students were also working on a robotic hand, which we filmed and which is so beautiful, it's become the handshake logo of the documentary. Back then you told me the eventual goal was to get all the motors and electronics in the palm rather than partially in the forearm as they were at that time. How close are you to reaching that goal? And why is this so important? 
 
Michael Goldfarb: Transradial amputees with an amputation near the wrist do not have space for motors or electronics in the forearm. This population of amputees requires the hand to be self-contained. The upper extremity prosthetics market is fairly small, and the current market model is modular, where an amputee purchases a hand, elbow, and/or shoulder as necessary. Therefore, only a fully self-contained hand would be embraced in the market as it has evolved. This issue may seem secondary, but if we are not cognizant of the market reality, we are much less likely to successfully translate our work to the marketplace, and therefore much less likely to improve quality of life for our target population.

Regarding our progress in this regard, our current hand prototype has all motors contained in the palm of the hand, and we have over the past year developed all the electronics to integrate into the palm. We plan to have a fully self-contained hand, with integrated motors and electronics, complete by this fall.

DP: Commercialization is trickier for upper limbs because the number of upper limb amputees is so much lower than the number of lower limb amputees. So what are the prospects of having any commercially available robotic hand in the near future?  Although there's been quite a lot in the media about robotic arms and the DARPA Revolutionizing Prosthetics Project some amputees I've talked with express frustration that there is still not a single one available. What's going on? Any idea of when the Vanderbilt hand might become available?

Michael Goldfarb: Assuming our evaluations of the hand continue to indicate that it would be an asset to upper extremity amputees, it is definitely my intention to make it (and a wrist and elbow under development) available to the amputee population. You’re absolutely right about the market size (probably 1/10 of the lower limb market), and hence the motivation for the self-contained hand previously discussed. In recognition of the small market, we are developing our upper extremity prosthetics under federal funding, and we intend to develop the hand into a “pre-product” prototype, such that a commercial partner need not incur significant investment or risk to bring the technology to market.

Another reason for the relatively slow translation of dexterous hands to the marketplace is what I call the control bottleneck. That is, the added dexterity of a multigrasp hand is not useful if the amputee cannot easily and reliably access the additional functionality. There currently are not well-developed or accepted methods that enable amputees to dexterously control multi-fingered hands. A lot of the academic work in this regard focuses on relatively invasive technologies that are most likely a number of years from the marketplace. My group has been developing approaches for control interface that appear to have real promise for near-term commercialization. I hope that advances in this regard will greatly facilitate the translation of dexterous hands to the market in the near term.

DP: In the film, you say that you're greatest wish is to someday walk down the street and see someone wearing the leg or walk into a restaurant and see someone using the hand.  You told me that you are always aware of the economics--that there's no point in designing something wonderful that no one gets to use, that's not what you're in it for.  Well throughout the making of this film that issue has haunted me. All this intriguing technology, and just who is going to get it? Many amputees can't even get what's available now.  So any idea on how this is going to work?

Michael Goldfarb: This is an important question, and also the aspect of this endeavor that I know the least about (I’m learning as I’m going). One reason we partnered with Freedom is because they understand very well the business of (lower limb) prosthetics. They have constructed a strong business plan and business model for the leg. A strong business plan requires selling legs, and if you’re selling legs, people are being fitted with them. Importantly (to me), the projected cost of the leg in Freedom’s model is significantly lower than some other “high-tech” legs, which should make it available to a larger cross-section of amputees. Market success requires that the technology offer substantive value to the amputee, and also requires that the device be translated to the market with a viable business model. Hopefully we have delivered on the former, and I believe Freedom has the expertise and infrastructure to deliver on the latter.

DP: How did you get into this field, were you always interested in robotics? Or prosthetics?

Michael Goldfarb: I’ve been interested in robotics as an assistive technology for improving quality of life for disabled persons since I was a kid. Incidentally (since you’re making a film), I remember watching a news or film segment as a kid on TV that showed early research on myoelectric arms (would have been sometime in the 70s). The clip showed EMG electrodes on an arm (I think bicep and tricep) being used to move a myoelectric elbow, and I think that sold me on this line of work. I interned in a prosthetics lab (at the Atlanta VA medical center) when I was in high school, interned in the Rehab R&D department at the Atlanta VAMC while in college, and pursued prosthetics and orthotics opportunities throughout college and graduate school. This area has always appealed to me as an appropriate application of technology, and one in which I could make a contribution.

DP: I'm curious about the word  "mechatronics." When did this word come in to being and what does it cover?

Michael Goldfarb: This word was trademarked by (I believe) Yaskawa (a Japanese robotics company), I think in the 60s, to describe the integration of electrical, mechanical, and computer systems. The term gained popularity, and Yaskawa later released the trademark. It is basically just a more generic term for robotics.

DP: Any issues you'd like to talk about that I haven't covered.

Michael Goldfarb: I think your questions covered the important points. Best of luck with the film.

David McGill is a participant in Out on a Limb, an Amputee Coalition Board Member, and a blogger. To see Dave in the trailer, go to the Indiegogo page; the trailer begins after Daria Price's introduction.

Q: What do you hope the impact of Out on a Limb will be?

David McGill: I think the public tends to associate prosthetics, first and foremost, with young, active individuals (i.e., the military, or elite athletes, like Oscar Pistorius). But the reality is that most people with limb loss are very different from that demographic. And yet, the 75 year-old who rebounds from an amputation as a result of diabetes is no less heroic, in her own way, and her story is no less powerful, than that of a Private First Class or a World Champion Paralympic athlete. So I hope that the film introduces people to that broader range of people that limb loss has touched, and shows the power of their' stories - stories we typically never hear.

Q: How do you think the advances in prosthetics will impact amputees?

DM: Prosthetic advances will continue to have a positive, life-changing impact on amputees. As an example, before I switched from my old knee to the one I wear now, I thought I was as functional as an above-knee amputee could be. I didn't really believe that there were any limitations on what I wanted or chose to do.