March 1, 2009
A Call to Arms: Veterans on the Front Lines of Prosthetics Research
The Iraq war has produced thousands of wounded veterans, propelling research into the ultimate ergonomic challenge: the perfect prosthetic.
Military amputees now find themselves on the front lines
of prosthetics research, with each new development promising more than mere mobility.
“I lost one limb in Iraq,” says Garth Stewart, a 26-year-old Army veteran, reclining on the futon of his dorm room at Columbia University, a glint of metal peeking from his trouser leg. “And in return I’ve gotten at least twenty.” A blast outside Baghdad in 2003 made pulp of his left foot, forcing doctors to sever his leg seven inches below the knee. Stewart, like many military amputees, now finds himself on the front lines of prosthetics research, with each new development promising more than mere mobility.
He has had a leg for running, a leg for swimming, a leg for grappling. He’s had gray legs, flesh-colored legs, legs with balls, computer-programmed legs, plastic legs, carbon-fiber legs, and titanium legs too.
He has had a leg for just about every occasion. (Indeed, Stewart has been photographed drinking beer out of at least one of them.) Today, the ex-gunner marches around campus, where he’s a senior studying history, in a simple mechanical contraption that mimics the J-shaped curve of a human foot and feels, as he describes it, completely natural. “I really capitalized on my investment,” he deadpans.
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Three decades ago, Stewart would have had little more than a wooden foot. Either that, or he would’ve been dead. But refinements in medicine and armor have guarded against the direst consequences of war, allowing Stewart and nearly 900 other soldiers to emerge from combat alive if not physically whole. According to a 2004 Senate report, amputees make up 6 percent of the Iraq war’s wounded, compared with 3 percent in previous wars. This represents just a sliver of total sales for the nation’s $900 million prosthetics industry, whose primary customers have diabetes, AARP cards, or both. Even so, the war has trained the klieg lights on wartime amputees, bolstering R & D funding and, in turn, innovation. About $50 million from the Defense Advanced Research Projects Agency has gone toward developing intelligent upper limbs. Soon, amputees will be able to sense and manipulate objects as they would with a real hand. They will wield mind-controlled Luke Arms (so named for Luke Skywalker). They will traipse about on electronically powered feet that make the wearer feel as if he’s floating on air. “If you plot prosthetic innovation against time, you’ll typically see a spike after every major war,” says Hugh Herr, a biomechanics expert at the MIT Media Lab and an amputee himself. He is researching the aforementioned bionic foot with $7.2 million from the U.S. Department of Veterans Affairs. It’s a science that needs a war to ad-vance even the tiniest increments, and for that reason, ever since the birth of the artificial limb, its aesthetic has largely been shaped by the experience of combat—for better and for worse.
It sounds like a coat being feverishly zipped up and down. Zipzip, zipzip, zipzip. In a corner of Room 213 at Walter Reed Army Medical Center, in a gym behind the dismal concrete face of the nation’s largest military hospital, Sergeant Kevin Brown lumbers over to a weight machine. Zipzip, zipzip, zipzip. He wears a prosthesis on his right leg, a bulky plastic thing that looks like something out of Transformers, and when he walks or climbs stairs or even sits, the limb cries out: Zip! The Power Knee is hailed as the world’s first powered bionic knee. It propels the user forward, compensating for the extra energy above-the-knee amputees expend walking (58 percent more than able-bodied people). Released in 2006 by Össur, an industry giant based in Reykjavik, it joins a host of intelligent artificial legs that take their design cues from Silicon Valley. Microprocessors, Bluetooth, ultrasensitive sensors: manufacturing body parts has fast become a digital affair. “I coach Little League football,” says Brown, an Iraq veteran who lost his leg in a motorcycle accident Stateside but who nonetheless remains active. “And this helps me off terrain, walking up and down hills.” Which isn’t to say the limb is foolproof. Brown lowers himself carefully onto the weight machine’s bench (zipzip). A sensor strapped to his good leg sends a signal to the Power Knee, directing the prosthesis into sitting mode. “But if you don’t sit down correctly,” Brown explains, “the leg can trigger itself and throw you up.” What’s more, the Power Knee weighs about ten pounds—more than twice as much as a standard prosthesis—and its battery lasts just three hours.
“If I’m going out somewhere, I’m not going to wear this,” he says. “It makes too much noise—and look at the size of it.” These are ultimately issues of streamlining, and Össur is at work on a successor that promises to be lighter, quieter, and longer lasting. “It was the first prosthesis to use powered movement, so what it does it does well,” says Brian Frasure, a clinician with Össur. “But it’s like anything else. When computers and cell phones came out, they were big and bulky, so each generation will get better.”
The technology has a violent past. One of the earliest written references to prostheses comes from Herodotus, the chronicler of the Greek-Persian wars, who noted in the fifth century B.C. that a prisoner escaped the stocks by slicing off his own foot and replaced the flesh with an improvised wooden contraption. At the beginning of the Renaissance, during a decidedly bloody epoch, the celebrated French Army surgeon Ambroise Paré designed the first articulated knee joint, a precursor to modern artificial limbs.
The American Civil War occasioned further innovation. James E. Hanger, the war’s first amputee, fashioned a widely distributed “Hanger Limb” from whittled barrel staves. (Hanger is now the country’s largest provider of prosthetics-patient services.) World War I saw the formation of the American Orthotic and Prosthetic Association, and World War II the creation of the Artificial Limb Program. Look to nearly any flashpoint in the history of prosthetics, and you will find a war.
Of course, the human body has never been easy to replicate, and for
every technological breakthrough, there are plenty of deficiencies. Arms have been particularly vexing to prostheses designers. This is partly a matter of markets: because leg amputations are more common in the general population, companies have more incentive to replace them. Thus a 1912 invention—a pair of hooks controlled by a harness—remains the industry standard. A funding bump after World War II gave way to the myoelectric hand, which uses electrodes instead of a harness, but did little to advance amputees’ range of movement. Lifelike hand coverings (detailed down to a patient’s veins) are ubiquitous now, but as anyone at Walter Reed will tell you, they can actually diminish agility.
In 2007 the U.K.’s Touch Bionics introduced the “first fully articulating and commercially available bionic hand,” to quote from the company’s Web site. The $50,000 i-LIMB has movable plastic fingers that mimic the human hand’s assorted curls and flicks through electrical impulses in the muscles of the residual limb. It has been heralded as the first major breakthrough in artificial-hand design since World War II. But in early tests, the i-LIMB proved too delicate. “When they initially designed these, they weren’t geared toward the twenty-one-year-old traumatic amputee,” says Craig Jackman, a prosthetist at Walter Reed. Touch Bionics has since modified the limb, strengthening tendons in the fingers, adding aluminum support to the thumb, and flattening the fingertips for better gripping. Retired Sergeant Juan Arredondo, who lost his left hand in 2005 in an IED blast, brags that with the i-LIMB, he can play basketball with his son, shoot rifles, and, most unexpectedly, eat grapes (which tend to burst in the grasp of clumsy hooks). For heavy-duty tasks such as yardwork, though, he still straps on the metal claws. As technology grows more complicated, researchers would be wise to sweat the design details—the materials, the shapes, the hardware. A thought-powered hand won’t do much good if there aren’t any fingers left to control.
A peculiar, and perhaps unsavory, aspect of this surge in prosthetic invention is that for the first time in American history it has allowed amputees to return to the battlefield. Already, 22 have redeployed. Stewart, who graduates from Columbia this spring, was nearly one of them. Months after leaving Walter Reed, his stump still swollen, he started training for a second tour in Iraq. He’d cart limbs in a satchel on mock missions in the desert, slipping on his running leg or his grappling leg or his marching leg as circumstances dictated. Stewart never went back to Iraq—mostly due to Army politics, he says—but the fact remains that with the help of some carbon fiber, he was sturdy enough to go another round.
The industry has noticed. Otto Bock, the world’s largest prosthetics manufacturer, has a $1 million contract to update its best-selling microprocessor-controlled limb, the C-Leg, to make it easier for military amputees to return to active duty. According to Gizmag.com, the new C-Leg will better address the exacting physical demands of combat, with ten programmable modes (walking, riding a bicycle, etc.) and faster response times to changes in walking speed and direction, which might be especially useful in a war-torn country full of improvised dangers to flee. It’s a curious development for Otto Bock, which was founded in 1919 to serve veterans of World War I. Nine decades on, the company’s motto, “Quality for Life,” takes on a dire new meaning. Instead of engineering for civilian life, it’s engineering human shields. Marshall Young, an industrial designer at Otto Bock, points out that technology developed for the military will eventually redound to the benefit of civilian amputees. It’s hard to disagree. War amputees represent less than 1 percent of Americans who have suffered limb loss, and diabetics increasingly dictate the market’s trajectory. Wars might refine the industry, but they don’t sustain it.
Back at Columbia, Stewart is in the university gym pulling on one of his legs, first unrolling a liner onto the stump, then sliding it into the prosthesis, a plastic-and-metal shank with a size 12.5 cross-trainer at the base. And then he’s down on a wrestling mat, practicing jujitsu with another Army veteran who, though half Stewart’s size, has what would appear to be an edge: his own four limbs. Stewart beats him every time, with or without the prosthesis. Now Stewart’s socking a pair of hand mitts, rocking back and forth on his legs, building power before he drives forward, left hook, right hook, uppercut. Only a keen observer would notice the slight hitch in his step as he shifts his weight. It could easily be mistaken for swagger. “It’s never too hard to get up,” goes a favorite motto of his, one he learned from his father. “Get up or die.” It should be no surprise, then, that Stewart has vaulting ambitions—teaching, joining a school board, running for state senate. None of them, as you see, involve sitting at a desk for very long. War nearly killed him, but the technological fruits of war will allow him to live a consummate life. It’s suggested to him that he might run for president one day. “In 2020,” he says without a moment’s hesitation, “I’ll be old enough.”
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