Thinking Bionics

May 27, 2008 by Sharon Adams
Left: Wildfire ranger Robert Anderson. Right: Jesse Sullivan demonstrates a prototype prosthetic. [PHOTOS: ROBERT ANDERSON; REHABILITATION INSTITUTE OF CHICAGO]

Left: Wildfire ranger Robert Anderson. Right: Jesse Sullivan demonstrates a prototype prosthetic.
PHOTOS: ROBERT ANDERSON; REHABILITATION INSTITUTE OF CHICAGO

Robert Anderson dreams of the day he can once again look at a pencil and pick it up with his left hand, something he has not been able to do since he lost most of his left arm and his left leg in a helicopter crash in 2006. The wildfire ranger from Grande Prairie, Alta., has a mechanical arm with a hook on the end.

In March, Anderson underwent nerve- implantation surgery that should make it possible for him to operate a revolutionary bionic arm. He is now waiting to see if the nerves have grown and will allow him to move the arm in response to his thoughts. And for that, Anderson will be very grateful, indeed.

The state-of-the-art technology behind this development in prosthetics might not have been possible in Anderson’s lifetime had it not been for funding from the United States military, and a strong commitment by the U.S. Defense Advanced Research Projects Agency (DARPA). One of the agency’s top goals has been to create the best artificial arm that money—or at least $70 million in research and development funding—can buy. With this in mind, it has funded two projects to develop an artificial arm that will look and function like the real thing—a prosthetic that is controlled by mere thought. “It’s going to give me back at least my elbow function,” explains Anderson. At best, “the new prosthetic will almost function like my real hand.”

Amputees work with small model parts to develop fine motor skills with their artificial limbs. [PHOTO: U.S. DEPT. OF DEFENSE]

Amputees work with small model parts to develop fine motor skills with their artificial limbs.
PHOTO: U.S. DEPT. OF DEFENSE

Although the DARPA-funded projects are aimed at improving the options for the new generation of U.S. military amputees with battle injuries from Iraq and Afghanistan, civilians are already benefiting, which is perhaps only fair since the military looked to the civilian world to find the critical mass of expertise that was needed to move prosthetic science ahead several generations. “We definitely feel the impact here in Canada,” explains Dr. Jackie Hebert, clinical director of the Glenrose Rehabilitation Hospital’s Adult Amputee Program, where DARPA researchers have been following Anderson’s progress. Located in Edmonton, the Glenrose is a research hub for neuromuscular disease and rehabilitation, and it sees approximately 100 new amputees a year, some of whom are Canadian Forces personnel.

“With the severe injuries coming back from Iraq and Afghanistan there was a great need to develop the next level of technology,” explains Lieutenant Joe Miller, U.S. Army Reservist and prosthetics expert. “We want a prosthetic arm to be real, to function like a natural arm and to look like a natural arm.”

Although the U.S. military has amputee treatment and rehabilitation centres, the civilian system has more experience with amputees. In June 2007, the U.S. Department of Defence reported it had more than 700 amputees who have lost limbs, mostly in Iraq and Afghanistan. By comparison, there are approximately three million civilian amputees in North America—170,000 new cases each year, most from vascular and circulatory disease.

DARPA invested in upper-arm amputee research because it is financially unfeasible in the private sector, explains Miller. Research to restore finger function would be very expensive, and the market (only two to five per cent are upper arm amputees) is too small for commercial development. As well, applicable developments can be adapted for leg prostheses. Also apparent was the fact that there was no one civilian institution that had all the technical expertise—let alone sufficient finances —to develop a space-age prosthetic. DARPA has managed to bring together research teams that cross professional, international and private/public boundaries, and the result is an evolutionary leap in prosthetics.

The first DARPA project, finished a year ahead of schedule, developed technological improvements that may have taken decades “if they happened at all,” says Miller. Civilian amputees will benefit in many ways. With research costs absorbed up front by DARPA, commercial development may make sense, adds Miller, and could result in a prosthetic that civilians can afford. And at the very least, the sharing of ideas will ensure new technology makes its way into less high-end prosthetics. Top-of-the-line, full-limb prosthetics can cost more than $50,000.

Ironically, the military need for better artificial limbs results from keeping troops safer in battle. Better resuscitation and surgical techniques and improvements in body armour have lowered the mortality rate from 30 per cent in World War II to 10 per cent in Iraq and Afghanistan, according to research published in the New England Journal of Medicine in 2004. However, modern munitions don’t just wound—they mangle. More soldiers survive, but with more extensive injuries.

Throughout history, prosthetic advances have followed wars. In about 200 BC, Roman general Marcus Sergius lost his right arm and then returned to battle with an iron hand holding his shield. In the U.S. Civil War the Union Army alone performed about 30,000 amputations. Lacking antibiotics, one in four amputees died, mostly from infections. The first Civil War amputee went on to invent an artificial leg and form a company that supplied wooden legs to the world. Prosthetic development sped up after the U.S. National Academy of Sciences Artificial Limb Program began co-ordinating research in 1945.

Over time, stiff wooden legs and pinned-up sleeves have gradually been replaced by functional limbs, the best with power-assisted, computer controlled bionic prostheses. Today, some artificial limbs are being attached to a titanium bolt in the bone in limb stumps. “It’s an exciting time for the Canadian Forces with all the new equipment, technology and headway in providing casualty and family support,” says Captain Kim Fawcett who lost a leg after being hit by a vehicle on Ontario’s Highway 401 in 2006.

The military attitude to retaining amputees has changed greatly over the last five years. Between 17 and 20 per cent of U.S. military amputees return to service, compared to 2.3 per cent between 1980 and 1988, according to a study presented in 2005 to the Association of Military Surgeons of the United States. Canadian brass have followed suit, recognizing some amputees are able to continue their military careers, says Fawcett, a squadron commander at the Royal Military College in Kingston, Ont., who is able to keep up with the demands of training cadets thanks to state-of-the-art prosthetics and an athletics-based rehabilitation.

The U.S. military funded two projects to develop prosthetics that perform as close as possible to the human limb. DEKA Research and Development Corp of Manchester, New Hampshire, was awarded the first, Revolutionizing Prosthetics 2007 (RP2007), and given two years to develop a “best technology” prosthetic arm and hand, including a neural interface. Completed a year ahead of schedule, it resulted in a 31⁄2 kilogram bionic arm with more joint movement than any prosthetic thus far. The user can unlock a door, shake hands, and reach above his or her head. This prosthetic is sensitive enough to allow the user to pick up very small objects and strong enough to lift hand-held power tools.

Miller is hoping patients at the Walter Reed Army Medical Center in Washington, D.C., will soon complete field tests of the new prosthetic. “What we’re doing now will determine if it’s ready for full commercialization.” Everyone involved is anxious to “get it into real-world use.”

The second, project, RP2009, was awarded to Johns Hopkins University Applied Physics Laboratory to push the science further. Phase one of this research will determine the extent a robotic arm and hand can be controlled by neural signals, and how much “feeling” the brain can pick up from prosthetic sensors. The second phase is aimed at producing an advanced neurally controlled prosthesis ready for human clinical trials.

Both projects involve international teams of dozens of experts. “That’s the really unique thing about this,” says Dr. Kevin Englehart, associate director of the Institute of Biomedical Engineering at the University of New Brunswick (IBME). “A small university in New Brunswick is working with some of the top labs in the world” and former industrial competitors are co-operating. “We’re all working towards a common goal and exchanging expertise.”

A window to this cutting-edge technology had already opened for Canadian amputees. IBME, which is associated with the New Brunswick Limb Deficiency Clinic, has had a key role in both projects.

To move our fingers, the brain sends a message through the nerves to the arm and hand, telling muscles to move fingers to type, change a baby’s diaper or any of a million other tasks. The challenge is to get an artificial arm to move as deftly and sensitively in concert with messages from the brain. This can be done using signals from muscles, from nerves or from the brain, explains Englehart. More limber movement, but stiffer scientific challenges await at each stage.

The myoelectric arm uses muscle signals, but the muscles are different from those that moved the lost limb. The user must be trained to control the prosthesis by flexing certain muscles, creating a small electric signal that is recorded by an electrode on the skin. The signal is relayed to a computer that switches motors in the prosthetic on and off in the right sequence for one of three movements: flexing the elbow, rotating the wrist or grasping. Disadvantages include slow movement (joints move one at a time), and the strength required to flex the muscles hard enough to produce signals.

Dr. Todd Kuiken, director of the Neural Engineering Center for Artificial Limbs at the Rehabilitation Institute of Chicago, has discovered how to reroute the body’s original signalling path. The major nerves formerly controlling hand function can be transplanted to other muscles. In Anderson’s case, nerves were transplanted into the biceps and triceps of his left arm, but other amputees have had the nerves transplanted into chest muscles. Once the nerves grow into the muscles, the muscles move in response to signals from the brain. Electrodes on the skin are still used to pick up and transfer signals to the prosthetic, but it responds better, says Anderson. To pick up a pencil with conventional myoelectric muscle control, he’d have had to think to flex the triceps or biceps in sequence, and then the prosthetic would move, joint by joint, to grasp the pencil. But if the surgery succeeds, “I’ll just have to think ‘open my hand’ and it will open.” With practice, even that will be simplified, hopes Anderson. “I’ll just have to think ‘grab my pen’.”

Englehart’s expertise comes into play translating messages from Anderson’s brain that will tell his prosthetic hand to grab the pen. “Our involvement in both projects has been the development of the embedded computer that is the interface between the person and the machine. If our project doesn’t work, they have a fancy robotic arm that really can’t do much.” But the prototype has proven itself, and research continues to make it work even better.

One surprise revealed in clinical trials was that information can travel back through the transplanted nerves to the brain. The brain believes the message is coming from the lost limb. Amputees report when someone touches the muscle served by the transplanted nerve, the brain interprets it as someone touching the hand, even when that nerve has been relocated in the chest. One amputee said her phantom limb felt cold, and found relief by putting a hot water bottle on her chest over the transplanted nerves. Further research may result in relaying messages from sensors on the prosthetic fingers to the brain, so the user can “feel” temperature, vibration and texture.

Other promising avenues of research include development of tiny sensors that can be injected into muscle; surgical techniques to improve arm and hand function; sensors implanted directly into nerves or the brain. Human trials with direct nerve recordings are expected to begin this summer, notes Englehart. “Muscles are easier to work with than nerves, which are easier to work with than the brain. But you can’t get as much information because you’re at the surface of the skin.”

Although DARPA envisages a day when a brain implant could control a prosthesis, “it’s still quite a few years away from being something practical, or even appropriate,” adds Englehart. “I’m not going to say it’s not going to happen, but there are many challenges. Maybe some day we’ll be able to magnetically implant something…I don’t want to be the one to say it’s impossible and be proved wrong 10 years from now. We’ve already had pretty dramatic benefits.”

Patients in the New Brunswick clinic may never have access to a RP2007 prosthetic, but they will see some of the whiz-bang technology in a home-grown product. IBME has received a $2.9-million grant from the Atlantic Innovation Fund to help develop an in-house version of a hand using DARPA project technology, says Englehart. “We’re going to make it as affordable as possible” by using smart manufacturing techniques and more accessible technology. “We feel we can keep almost all of the function and build something not much more expensive than what is already out there right now.”

Opportunities are opening up for researchers not part of the DARPA projects, too.

While DARPA researchers try to figure out how to get bionic arms to operate 24 hours a day without re-powering, Max Donelan of Simon Fraser University in British Columbia has found a way to harvest energy from walking. “The idea is to capture energy in the background while people are going about their everyday activities,” explains Donelan. His device harvests energy from muscles that work to slow the walking stride. This energy could then be used to power something or replenish a battery. He said someone wearing the Biomechanical Energy Harvester, which resembles an orthopedic knee brace, can generate enough electricity while walking to power 14 cell phones. He believes prosthetic applications abound. “You could use the healthy limb to power the artificial limb. With below-the-knee amputations, the knee on the injured leg could be used to power the foot,” he adds. Smaller versions could power prosthetic joints and implanted neurotransmitters.

Although these are promising developments it could be decades before such prosthetics are available to long-term amputees like Trevor Hooker, who lost his arm at mid-elbow in a train accident in 1991. He has a replica hand, a hook and a hockey attachment, but he usually doesn’t bother using a prosthetic. “I’d use it more if the thing actually worked; it doesn’t help you type,” says the Ottawa chartered accountant. It’s also uncomfortable. “The last time I actually wore it was for a wedding.” An avid athlete, he uses the hockey attachment but is leery of anything that might affect his golf swing.

Still, Hooker is following current developments. “I’d like something strong enough to carry groceries without undue strain on my back, nimble enough to tie shoelaces, and one that would eliminate the need for other attachments.”

He lost his arm too long ago to be a candidate for nerve transplantation surgery—at least for the moment. But who knows where the evolutionary leap in prosthetics will end? The DARPA projects have already resulted in a prosthetic with five operational fingers, controlled by thought. One day, perhaps, there will be a prosthetic good enough for typing, and surgical advances to allow Hooker to use it.

One Foot At A Time

When the Canadian Centre for Mine Action Technologies (CCMAT) asked Rob Gabourie to recommend an artificial foot for Third World workers injured by landmines, the answer was short and not so sweet.

There wasn’t one he could recommend.

So, the St. Catharines, Ont., prosthetics designer set out to change that.

“Available devices at the time were necessarily low-cost,” says Tim Bryant, professor of mechanical engineering at the Human Mobility Research Centre in Kingston, Ont., where Gabourie sought help to turn his design into reality. The centre is a partnership between Queen’s University and Kingston General Hospital.

It is estimated that between 70 and 80 million landmines dot the landscape in 90 countries, claiming more than 26,000 victims a year; survivors usually lose a leg. Earning the equivalent of $100 to $200 a month Canadian, many victims live far from prosthetics clinics. So what’s needed are prosthetics that cost little and last a long time.

Third World amputees often make their own or use a $5 artificial foot that isn’t flexible and requires more energy to use. These feet also need to be replaced a half a dozen times a year.

Gabourie’s inverted S-shaped foot stores and returns energy, putting a spring in the wearer’s step. Using injection moulding and long-wearing high-tech plastic, the foot can be manufactured in volume. Production costs are kept down by volunteer labour from Queen’s University’s mechanical engineering department, Dupont Engineering Polymers of Wilmington, Delaware, Dupont Canada, and Recto Molded Products of Cincinnati, Ohio.

The result is a long-lasting foot that’s priced at about $30.

The first model was tested for three years in Queen’s cyclical fatigue laboratory before field tests began in 2003 in a small town along the Thai-Cambodian border, one of the most heavily mined areas in the world. The design had to be tweaked for the hard-working farmers. A foot is usually designed to be used for walking on level ground, but add a 50 kilogram bag of rice, and it’s too springy, says Bryant. That was solved by stiffer material; a more realistic covering was also added.

The following year, funding from the Canadian International Development Agency allowed similar tests among landmine amputees in El Salvador. Changes were needed to accommodate farmers working coffee plantations on the steep sides of a volcano. Size, shape and stiffness of the foot had to be changed, and a new plastic used. As of March, the team was in the last stage of refining the design, and “if the current round of testing is successful, the foot would become available later this year,” explains Bryant.

With sporadic funding and volunteer help, the project moves more slowly than the team would like. Only a couple of hundred of the feet are now in circulation—and they’re all one size. “We want to increase the number of sizes available,” adds Bryant. But that means finding funding for new moulds in different sizes.

The volunteers have established a charity called Niagara Orthopedics Worldwide (www.noww.ca). Overall, the foot and the charity are seen as forward steps in lightening the load for Third World leg amputees.

Athletics And Prosthetics

Civilian and military amputees in Canada are benefiting from the United States military’s investment in research aimed at improving equipment and rehabilitation services for wounded soldiers.

“There’s a nice trickle-down effect,” explains Dr. Jackie Hebert, director of the Adult Amputee Program at the Glenrose Rehabilitation Hospital in Edmonton.

The large number of military amputees treated in the U.S. has allowed development of specialized amputee treatment centres. It has also caused a growth in expertise which the Americans are willing to share with their allies.

In 2007, a team of Canadian Forces medical personnel, civilian health care professionals and military amputees, including Captain Kim Fawcett of Kingston, Ont., and Master Corporal Paul Franklin of Edmonton, visited Walter Reed Army Medical Center in Washington, D.C. The group’s objective was to study the new technology and rehabilitation techniques, and then see what could be applied back home. Both Fawcett and Franklin say the visit paid off for them. “My experience at Walter Reed was amazing,” explains Fawcett, who lost a leg when she was struck by a car in 2006. “There is nothing like it (the centre) in Canada.”

After seeing the Walter Reed rehab programs, Fawcett concluded that “the possibilities for a higher-level of physical activity are endless.” In Canada there are far fewer military amputees and the Department of National Defence pays for treatment and rehabilitation services for these men and women in civilian programs. On its own, civilian rehabilitation wasn’t going to restore Fawcett to the operational level she sought. Using what she learned at Walter Reed and with the support of DND, Fawcett and her trainer developed a strength-training and rehabilitation program that she hopes will help others. In her case, the program allowed her to resume her military career and athletic pursuits. She is now working as a cadet squadron leader at the Royal Military College in Kingston, Ont. “I never stopped training,” adds Fawcett who is preparing for the Vancouver World Triathlon Championships in June.

Franklin contrasted his own rehab to civilian regimes. “I got more care,” he says. He spent more than a year, on and off, at the Glenrose. Civilian amputees generally receive six to eight weeks of rehabilitation, explains Hebert. Although the military funds longer rehab where warranted, provincial governments are “going to put it into…things that save lives (or) reduce wait lists—and rightly so, that’s our publicly funded system,” she adds.

Franklin used what he learned at Walter Reed to help establish a sports program that stretches civilian rehab time beyond the clinic. The program Freedom through Sport integrates fitness, sport, rehabilitation and peer support to help amputees make the transition from rehabilitation in clinics to their neighbourhood gyms and sports arenas.

It exposes amputees to more—and more enjoyable—opportunities to become physically fit, says Robert Anderson, a double amputee who went through rehab at the Glenrose. “Rather than saying ‘go to therapy’ they can suggest we do something fun. I’d rather play hockey or soccer.” He says the program also suits amputees who don’t want to (or can’t) go back to the clinic or hospital after release.

The program is a collaboration between the Northern Alberta Amputee Program (NAAP), the Steadward Centre for Personal and Physical Achievement at the University of Alberta, and the Glenrose. “We can do running clinics, advanced amputee skill clinics, show amputees how to use the weight machines and treadmills, so they can safely go to a normal gym and work out,” adds Franklin, who works in casualty support at the Canadian Forces’ Land Forces Western Area.

Although the majority of the Glenrose’s patients are older and have had amputations following vascular disease, “we have 20 to 30 patients per year equally motivated and driven to get back to a higher level of sports performance,” says Hebert. The sports program provides “good peer support and mentoring” to military amputees recovering away from their units.

It can be used by military amputees as needed, says Franklin. Programs are “ready to go when soldiers come back. So, if we need a peer support program, we can set up a course easily because we don’t have to start from scratch. It’s a good thing about using the civilian system.”

Franklin hopes NAAP can help community gyms and fitness centres become more amputee-friendly by providing expertise, equipment, and suggestions on the use of space to accommodate special needs. His dream is that Freedom through Sport will spread from the Steadward Centre across the country.

Email the writer at: writer@legionmagazine.com

Email a letter to the editor at: letters@legionmagazine.com

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