What’s Next? DARPA’s Revolutionizing Prosthetics Projects Get a Grip on Reality

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By Judith Philipps Otto

In December, The O&P EDGE gave you an exclusive look at what's next for the Modular Prosthetic Limb (MPL)- one of two major upper-limb projects to come out of the Defense Advanced Research Projects Agency (DARPA) Revolutionizing Prosthetics (RP) program. This month, The O&P EDGE takes a look at what's next for DEKA Research and Development Corporation's "Luke Skywalker" arm project.

An archival "Peanuts" cartoon once featured an ambitious Linus suddenly and zealously determined to improve the scope of his knowledge: "Let's take about ten minutes, Charlie Brown, and you can tell me everything you know."


It's easy to imagine DARPA Revolutionizing Prosthetics Project Manager Stewart Coulter as Charlie Brown to my naïve Linus as we discussed the status of the "Luke Skywalker" project by DEKA Research and Development Corporation, Manchester, New Hampshire. The "Luke" arm is a sophisticated, high-tech mechanical arm that integrates the best that modern engineering, medicine, and prosthetics can offer. Was it more daunting to answer DARPA's call to transition the greatest and most significant incremental advance in upper-limb capability possible within a tight two-year deadline-or to answer my demands to condense the multiple complexities and myriad separate challenges of an already-extended project into a virtual 25-words-or-less?

Since January 2006, when DARPA launched the two-year DEKA project and the four-year Modular Prosthetic Limb (MPL) project, both have made amazing strides toward accomplishing their separate missions. The DEKA arm project was so successful, in fact, that the team received continuing funding to support additional development past its original two-year deadline and into clinical studies. (Editor's note: For more information about the Johns Hopkins University (JHU) Applied Physics Lab (APL) accomplishments relative to the MPL project, see "Armed for the Future: DARPA's Revolutionizing Prosthetics Project Nears Completion," The O&P EDGE, December 2009.)

According to Coulter, the primary challenges the project presented were threefold: the interface with the patient, the hardware and software of the arm itself, and the control method and mechanism. "Those are the three big problems, which we identified early on-and we spent a lot of time and effort coming up with a good solution for them," Coulter says. "Solving two of the three doesn't do you any good-the solutions to them are interdependent. Because addressing them simultaneously was so important, it was a great thing to have a team that works so well together."

The user studies that are currently under way are going well, Coulter reports. "We're very happy with how the project is going; we've had great feedback from the subjects, [and] we've had great results from the people we've been working with..."

Will the "Luke" arm better serve military or civilian amputees?

DARPA'S non-invasively controlled advanced prosthesis developed under the Revolutionizing Prosthetics 2007 program. DARPA/DEKA photo.

"We've worked with both civilian and military or ex-military users, determining what they need and how we can best support the entire set of people who could take advantage of this arm," Coulter says. "Our goal is to make an arm that offers benefits to the people who need it-and that's what we're really focusing on."

Has the project changed course significantly along the way?

"There was a very clear mandate to improve the state of the art, and I think we've done a lot to accomplish that," Coulter says. "There are always differences from what you originally thought and what people want, but that's the whole point of doing all of this work with the users-and we're very, very happy with the feedback that we've gotten.

"Are we done? No, but I think...we're on the right path and pushing things in the right direction during this development process. We're learning a lot that we'd like to spin back into the product before it actually comes out the door, so when we do release it, we are able to really take advantage of everything we've learned from all the people who have given us their time and effort to help us improve it."

The contributions from others besides DEKA's own sizeable team of engineers, technicians, and support staff are significant:


Randall Alley, CP, LP, FAAOP, of biodesigns, Santa Monica, California, for example, was recruited about six months into the project, when the DEKA team recognized a need to take a better look at the interface design, which had previously been a source of numerous complaints from military amputees.

"I was selected for the project based on some of my ideas, as well as my new interface design-which was a radical step away from traditional designs," says Alley, who makes frequent flights from California to New Hampshire, where he works closely with DEKA and Next Step O&P, Manchester, New Hampshire-also a clinical partner on the project.

"There were conference calls and e-mails in between, of course, but when it came to actually creating the unit and putting it on an individual, I flew out to put my interface on."

Photograph of the "Luke" arm courtesy of DEKA Research and Development Corporation

Alley's original High-Fidelity Interface design now has some "additional goodies attached"-courtesy of the DEKA engineers-and it is now under scrutiny during clinical studies. Alley says that his current role is to provide clinical feedback to the engineering development team, continue optimizing the interface design during user studies, and provide initial training to VA clinicians on the interface design and fitting process. Like Coulter, he is enthusiastic about the project's success to date: "We're all very excited. We've had some fantastic leaps ahead in the last year or so.

"The benefits of the study itself were quite different from what I experience when I fit patients because my goal is to get that patient up, running, and functional," Alley continues. "In this case, our goal was to push the limits and see what we could achieve. Having the freedom to do that was very beneficial in terms of satisfaction, as well as what we developed. Working with Next Step O&P as a strategic partner rather than a prosthetic competitor-as is often the case in our industry-was an incredible, enjoyable, and eye-opening experience in terms of what we could accomplish together on a project."


Matt Albuquerque, CPO, owner and vice president of Next Step O&P, agrees. "The weight of the DEKA arm is currently around nine pounds, which is quite a bit heavier than any of the current commercial products available right now, necessitating an interface that really is above and beyond what we're currently using," Albuquerque says. "Thanks to Randy and the design that he came up with, we were really able to take that weight and distribute it onto the proper areas and really help people be comfortable.

"Some of the stuff is hard to build, and beyond the scope-but because we have such a vested interest in wanting to see this get to our patients, I think we're willing to do those things above and beyond, and we're not necessarily worried about getting paid for everything we do."

And indeed, although most DARPA project partners invest significant time, materials, and effort over and above their project payment from the Department of Defense (DOD), it's a willing and cheerful contribution. The benefits to Albuquerque and his company are admittedly significant. "Being able to offer it to our clients is first and foremost," he says. "On a secondary, business level, I'm sure both Randy and I would love to be involved with the continuing training of the fitting of the interface and teaching future practitioners the importance of getting the interface done correctly."

As consultants for DEKA, Albuquerque and Alley are currently fitting people for home clinical study use and advising DEKA on the arm's optimization for future use.

"Good technology married to a bad interface ends up with a bad result," Albuquerque stresses. "It is crucial that the people in charge of the interface know how to do it correctly and are able to handle the weight of that arm."

Are We There, Yet?

Coulter counters, "Are you ever done? There are always new things, new technologies that you can take advantage of, and better and better feedback from people-and we're looking forward to continuing to improve things based on that. But right now our focus is very much on getting this version out the door, making it available to people, and continuing to improve it from that point forward."

Commercialization is a big part of that focus, Coulter acknowledges. "We're very much pushing on the process because we realize that's a very critical part of it. In parallel with the technical work is work on manufacturing-process development-and this is something that we have done a lot with a number of other products. That's a big part of what we're doing, now."


Getting a prototype through the commercialization process and into the hands of consumers in the market has proved historically to be a tricky proposition, however. Kevin Kelley, international project coordinator at Otto Bock HealthCare, Minneapolis, Minnesota, has an insider's perspective on the complexities involved in the commercialization process. Otto Bock was the initial commercial partner for the JHU APL MPL arm project, and Kelley managed Otto Bock's participation.

"That has always been the built-in tension of the DARPA project," Kelley points out. "You have a reach-for-the stars project where you're doing all kinds of things that have never been done before, and end up with prototypes that are good proof of concept. They prove that yes, it's possible to do some of this really difficult stuff. The reality, though, is that as a manufacturer there's a world of difference between building one prototype that works and actually getting to a product.

"If you get to a product, you have to be able to manufacture in quantity. You have to have all the regulatory and safety approval, you've got to have training and education, the software should be stable, you need service and maintenance-and even if you do all that correctly, you need to already start working on performing studies so that you can prove that the new technology is worth it in order to get reimbursement.

"The challenges are great," he continues. "So we always have R&D going in our pipeline because we realize that the path from R&D to product is a long, hard slog.... We have to be the conservative ones who point out the realities we face. It's not the most fun role, but it's reality."


"Conservative" need not mean "reactionary," however. Brad Ruhl, president and CEO of Otto Bock HealthCare, points out that his company brought to the DARPA project a number of things already in the works in Otto Bock's lab. "We know that investing in development for shoulder disarticulation prostheses, for example, almost never returns a financial payback." There simply aren't enough people in this patient population to make upper-limb prosthetic development financially viable, Ruhl says. "But there's a moral and ethical responsibility to invest, nevertheless-to move that technology forward so these patients have the benefit of advanced technology. So we were already making an investment prior to the project."

Otto Bock's additional investment in the MPL arm project was also costly: the company's contribution exceeded what it received in funding, Kelley notes, and included keeping an engineer working full-time on the project during the non-funded nine-month interval between Phases I and II; it also involved the participation of more than 35 different employees (engineers, technicians, testers, and machine operators). "In total, we received about $2.6 million in funding and contributed about $400,000 of our own funds toward the project," Kelley says.

He points out that the program's first prototype was completed only seven months into the project, largely as a result of the years of preliminary work Otto Bock had spent developing some of the components, including the "bus" that connects them all with its three wires. "The AXON™ Bus-already in use in our C-Leg™-provided all the power and all the intelligent control, enabling JHU APL's software to control the arm's seven degrees of freedom."

Far-Reaching Implications

The impact of DARPA's projects are far-reaching, including the imminent launch of a new, fully integrated Otto Bock AXON™ Bus myoelectric prosthetic system, Ruhl says, which was already well-advanced in their R&D pipeline but was expedited toward commercial viability by lessons learned during the DARPA project.

Kelley agrees. "A lot of things happened sooner than would have been possible otherwise, and a lot of good collaborations were made. Some of our own work with targeted muscle reinnervation (TMR), for example, was accelerated, resulting in products like the DynamicArm for TMR."

Ruhl speculates that the TMR bridge to thought control of prosthetic devices, which is currently focused on upper-limb application, might possibly be applied at other levels of amputation, including lower limb.

DEKA's arm is creating waves, too, and its collaborators also report serendipitous bonus benefits:

By validating the effectiveness of Alley's interface over a significant period in which the subjects were closely monitored, the project also enabled him to more assertively apply the concept to an ever-widening scope of both upper- and lower-limb patients in his own practice.

"biodesigns has...specialized for years in upper limb, but now, because the High-Fidelity Interface has shown so much promise for all amputation/amelia levels, we'll be specializing in high-performance lower limbs as well. I'm really excited about that; I've applied for a patent on the design, and I'm looking forward to completing studies to determine how effective it will be in a lower-limb application."

Albuquerque acknowledges the value of his unique opportunity to work "not only with one of the world's greatest inventors-Dean Kamen-but also with other great practitioners in the industry, like Randy," which has led to another beneficial discovery. "I've started using Randy's interface design on people who are wearing conventional body-powered systems, and there has been a tremendous benefit to them in terms of comfort," he says. "That's only the beginning of the ripple effect," he predicts, "as we take what we learn from the project and apply it to all areas of prosthetics-not necessarily just the high-tech parts."

Coulter agrees that the DEKA Arm will generate additional benefits beyond the immediate results. "We've taken a lot of technologies from other areas and applied them to the arm; we've learned a lot that will add value in other areas, as well, and there's a strong desire to have that get out there and provide that value."

Is the Price Too High?

Such value may be difficult to balance against the reimbursement challenges for either of the DARPA arms, which are likely to fall somewhere on a scale between significant and mindboggling.

Coulter observes that the reimbursement question is always "interesting," but points out that "it's one that we've worked on before, and one that we're actively pushing on now. It's always a concern, finding ways to make the technology as available as possible to the broadest spectrum of people. It's something we're definitely considering as we go through the design process."

Kelley believes the only solution-at a time when everyone is trying to cut budgets-is relying on evidence-based practice. "We have to prove how much better the new technology is with documented results-and it's going to take time. We're going to have to invest a lot in studies.

"One reason the military needed to get involved in these projects is because it's very hard for the market alone to justify the investment," Kelly continues. Upper-extremity amputees represent only about 10 percent of the amputee population-with transradial upper-extremity amputees comprising 70 percent of that 10 percent."

DARPA's investment was motivated by the higher percentage of such patients among the military population, and certainly, Kelly notes, military casualties will be early adopters.

"A beautiful arm like...the MPL...even if it performs perfectly, which is very, very difficult-is going to come with a price tag between $100,000 and $200,000."

Add to this the complications, in the case of the MPL arm, of gaining Class 3 medical-device regulatory approval for the neural interface aspect-proving the safety, verifying the data, and completing the clinical studies-and it seems probable, Kelley says, that whatever advances are made are going to have to be done in careful stages-one articulated finger at a time, perhaps.

"Of course, this economy forces everyone to make difficult choices. It's a very challenging environment for introducing brand new, expensive technology."

Especially in light of a depressed economy, Coulter, says. "DARPA's commitment to this project has been tremendous; we've been able to continue pushing on this and really working on solving the problem for people who need this technology." Whether the state of the economy will impact the Luke arm from a market perspective, "that's a process that's still being defined."

This project is sponsored by the Defense Advanced Research Projects Agency (DARPA) and the U.S. Army Research Office. This information does not necessarily reflect the position or policy of the government; no official endorsement should be inferred.

Judith Philipps Otto is a freelance writer who has assisted with marketing and public relations for various clients in the O&P profession. She has been a newspaper writer and editor and has won national and international awards as a broadcast writer-producer.

DARPA RP2009 Retrospective

Col. Geoffrey Ling, Defense Advanced Research Projects Agency (DARPA) Revolutionizing Prosthetics (RP) program manager, provides The O&P EDGE with his assessment of the Revolutionizing Prosthetics program.

The O&P EDGE: Are you satisfied that the DARPA Revolutionizing Prosthetics project realized its objectives as originally envisioned? In retrospect, what turned out to be the most significant barriers to success, and were they unexpected or had they been anticipated?

Ling: We have had many unexpected breakthroughs but need to continue to build relationships and understanding of the regulatory procedures required to bring this technology to market at affordable costs to those it will benefit. A big challenge, thankfully, is the small number of amputees, but it makes it hard for industry to make a business case to become a commercial manufacturer. We are seeking to reach out to other patient communities and will be exploring those ideas in the coming months.

The O&P EDGE: What's the next step? Will DARPA move on to fresh creative challenges and hand off the follow-through/production/commercialization chores to others? Does your office have any continuing involvement with it at all beyond this stage?

Ling: DARPA is going to transition our strap-and-go [DEKA] program in the next year. We have assisted our performer with building relationships that are necessary to facilitate that transition and will increasingly defer to the transition partner for ways to make the technology better suit the needs of the user community. Our neural-control program will enter a third phase, and as that is in the planning stage, it is best to describe what we plan once we have a contract in place. After transitions, DARPA will provide input to ensure the efficient flow of rights and licenses to other agencies, but otherwise our involvement stops.

The O&P EDGE: I'm hearing of a new DARPA robotics initiative. Is there any connection with the RP program? Did the new initiative evolve from RP, or was it inspired by it? Is there any carryover or transference from the earlier program? Might the new autonomous robotics initiative benefit from some of the lessons learned, progress made, and/or personnel recruited to achieve RP goals?

Ling: DARPA program managers maintain dialog when working on related programs; we have several robotics and related programs with separate goals and paths to achieve the goals, and each usually starts as a unique idea to meet specific requirements, then leverages whatever they can from other programs to be good stewards of the taxpayer's dollars.