Bionic Legs, i-Limbs, and Other Super Human Prostheses You'll Envy
Save your tears for Tiny Tim. A boom in sophisticated prostheses has created a most unlikely by-product: envy.There are many advantages to having your leg amputated.Pedicure costs drop 50% overnight. A pair of socks lasts twice as long. But Hugh Herr, the director of the Biomechatronics Group at the MIT Media Lab, goes a step further. "It's actually unfair," Herr says about amputees' advantages over the able-bodied. "As tech advancements in prosthetics come along, amputees can exploit those improvements. They can get upgrades. A person with a natural body can't." Herr lost both his legs below the knee in a Mount Washington climbing accident when he was 17, but says that shouldn't inspire pity. Instead, by donning whirring, whispering, shiny supermachines -- the robotic ankles that can propel him across the room in 400-watt bursts -- Herr has been given: Power. Allure. The strange animal magnetism of the very bad boy.
"When the prosthetic technology doesn't work," Herr says, "and the [amputee] is limping and he can't run and he's hurting, then nobody feels threatened, because that person is labeled as 'cute' and 'courageous.' " He leans forward in his office and crosses his aluminum shins with an audible clink. "But when the technology works, when it can make you stronger or faster than you were, it overnight becomes sexy and powerful and threatening. Overnight."
Anybody who hears "prosthetic" and thinks "peg leg" might wonder about Herr's sunny hubris. The thought that an artificial limb could make anybody stronger or faster, or confer social advantage, is an opinion ripe for skepticism. Wearing one is inconvenient at best. It often hurts. It can break. It is obvious proof of loss. It seems by its very nature to announce a lack of health or vitality.
Yet much of the dissonance in Herr's "prosthetics as progress" thesis stems from the undeniable fact that for years, prostheses were irredeemably ugly, off-putting, scary. Who would call a disembodied limb a "design object" to be lusted after, like an Audi or an iPhone? Who would consider herself better, or more beautiful, than a person without one?
"When I first got this job," says Stuart Mead, CEO of Touch Bionics, a prosthetics and robotics firm based in Scotland, "it struck me how depressing it all was. Prosthetics were at the back of the hospital, the downstairs office, the back room. The look of most of these devices was horrible -- half-human, half-plastic. This frightening pink color."
Just wearing one could induce shame: The Barbie doll cosmesis (a cosmetic cover), tipped with a hook, acted like social repellent, pushing the user and the observer apart. "It was like having a scarlet letter," says Marshall Young, an industrial designer for Otto Bock HealthCare, of the old-style prosthetic limbs. "It was, 'I've got this damn thing and now my life sucks.'"
All that is about to change -- not only because prostheses are being built with materials found in sports cars and jet airplanes; or because designers are giving their creations an exuberant, unapologetic carbon-fiber sparkle; or even because nerve reintegration and myoelectrics are offering some amputees the joy of normal function. The biggest reason for amputees' unlikely rise into a new, socially advantaged class comes from something much more mundane: profit. The prosthetics business is set to explode, and its products will make amputees stronger, faster, and, to some, more desirable than the rest of us.
Not surprisingly, the money is following the market. MIT's Herr cofounded a company called iWalk, which has received $10 million in venture financing to develop the PowerFoot One -- what the company calls the "world's first actively powered prosthetic ankle and foot." Meanwhile, the Department of Veterans Affairs recently gave Brown University's Center for Restorative and Regenerative Medicine a $7 million round of funding, on top of the $7.2 million it provided in 2004. And the Defense Advanced Research Projects Administration (DARPA) has funded Manchester, New Hampshire-based DEKA Research, which is developing the Luke, a powered prosthetic arm (named after Luke Skywalker, whose hand is hacked off by his father, Darth Vader).
This influx of R&D cash, combined with breakthroughs in materials science and processor speed, has had a striking visual and social result: an emblem of hurt and loss has become a paradigm of the sleek, modern, and powerful. Which is why Michael Bailey, a 24-year-old student in Duluth, Georgia, is looking forward to the day when he can amputate the last two fingers on his left hand.
"I don't think I would have said this if it had never happened," says Bailey, referring to the accident that tore off his pinkie, ring, and middle fingers. "But I told Touch Bionics I'd cut the rest of my hand off if I could make all five of my fingers robotic."
Young, of Otto Bock HealthCare, says Bailey is far from alone. Amputees are now regularly removing healthy tissue to make room for more powerful technology. "I see it every day," he says. "People will get a second amputation -- move their amputation up their leg -- to get the prosthetic equivalent of a hotter car."
Orthopedic surgeons often consider amputation the equivalent of failure, Young says, and reflexively save as much of a damaged, injured, or diseased limb as possible. But in leaving lots of human being, they create a bigger problem: There is little room left for high-performance machinery. Now, the allure of that machinery has become so powerful that amputees are routinely taking the extreme step of paying out-of-pocket for what the industry calls "revisions."
"It's very simple," Young says. "Prosthetic feet act like leaf springs on a truck -- the bigger they are, the longer the lever arms, the more energy storage and return you get. With enough clearance, you can go from a walking foot to a higher-performance running foot. So people with too much residual limb are in a position of saying, If I want to go to a knee that will let me play basketball, I will have to downgrade my foot. They'll say, Take four more inches, because I want that cool Corvette."
As the rhetoric heats up -- as robots perform surgery and build automobiles, and as the suspicion grows that our original equipment is somehow deficient -- Herr offers some perspective. Poor eyesight, he says, is a medical condition. Eyeglasses are prosthetic. And while they were once purely medical devices, they're now expensive fashion items.
"Often people can have contact lenses, but they choose in certain social environments to wear their glasses, because it looks hot. People put glasses on to make themselves look more intelligent. To augment their appearance, not just their performance."
Herr's suggestion, of course, is that the better prostheses make us perform, and the more glamorous they look, the more beautiful they will make amputees seem, too, even though their sheen, contour, texture, and color have ceased to look human.
"What is the obsession with looking human?" he says. "You think the only beauty is human? Bridges can be beautiful. Cars can be beautiful. Cell phones can be beautiful. They don't look biological. So why do you anticipate 30 years from now that amputees will give a shit about human beauty? They won't. Their limbs will be sculptures."
MIT professor Hugh Herr, 45, who lost his legs in a mountain-climbing accident, says 70% of amputees have hip and back problems. One reason: When walking, there is no "lift" or "push" forward from the prosthetic foot, which leads to a violent, uncushioned impact on the forward foot. For the able-bodied, that lift is "like the hand of God," he says. So Herr invented powered iWalk ankles (shown) that use hydraulics, pulleys, and batteries that can provide a 400-watt boost out of each step. "I don't walk my legs. My legs walk me.""Last year," says Carrie Davis, "I went down to a clinic and met this lady who saw what I could do with my arm, and she said, 'I want one like that.' She wanted to knit." Davis was born with one forearm missing and has 12 dif-ferent hands, or "terminal devices," each designed for different tasks. Her favorite: the carbon-fiber-sheathed bionic hand (shown) from Touch Bionics. "I get a lot of attention walking into a room with i-Limb. I love it. It's bad-ass looking." The limb uses a battery and a force-sensitive resistor to respond to her muscle contractions and impulses.
