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When the National Academy of Sciences established the Artificial limb Program in 1945, the options for amputees were few: crude, wooden prostheses. And for those who chose none: life confined to a wheelchair. Fast-forward 65 years and the United States faces an influx of amputees from the conflict in Iraq, but the opportunities for soldiers returning home from war with an amputation are far more advanced. Listed are some of the most important advancements in robotic prosthetics in the last 20 years that give artificial limbs more function than ever before.
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1. Prosthetic Foot Materials
For years, wood was the dominant material for a prosthesis. But over the last 20 years, materials have emerged to give greater comfort and confidence for amputees. Susan Kapp, an associate professor of orthotics and prosthetics at the University of Texas Southwestern School of Health Professions, says if a prosthetic foot is cut open, most likely the material found inside is carbon fiber. Carbon fiber, according to Kapp, is a much more life-like material, giving amputees a sense of life in their foot. Thermoplastic sockets give prosthesis recipients extended comfort at the site the prosthesis is fitted, and titanium gives a prosthesis longer life and durability.
U.S. Army/ Roger J. Mommaerts Jr.
Bluetooth technology made the jump from the cell phone industry to prosthetics in 2007 when Marine Lance Cpl. Joshua Bleill received two artificial legs after seeing combat in Iraq. Each leg was fitted with a Bluetooth device. Bluetooth is more often recognized for its ability to connect pieces of technology together without the use of wires. In Bleill’s case, the Bluetooth devices communicate with each other to regulate stride, pressure and speed in the prosthetic legs. The benefit of Bluetooth technology, according to Ryan Blanck, a prosthetist at the Center for Prosthetics and Orthotics at Brooke Army Medical Center in Ft. Sam Houston, Texas, is the programmability of the software. “We can take that technology an further develop it to adjust to a patients need,” Blanck said.
3. Microprocessor Knees
With an onboard computer within the prosthesis, people with above-knee amputations have greater control over walking, stopping and moving on inclines. These “robotic” knees, termed microprocessor knees, analyze the pressure an amputee puts on the missing limb. Also contained within the knee is a fluid control unit, which the microprocessor monitors to appropriate joint resistance when walking on inclines. Available since the early 1990s, microprocessor knees have revolutionized the arenas of safety and stability for people without knees. Kapp says people that receive the prosthesis don’t have to worry about the knee buckling under them.
Touch Bionics Inc. and Touch EMAS Ltd.
4. Myoelectric Technology
When the i-LIMB hand debuted in the United Kingdom in July 2007, people caught a glimpse of the future of robotic prosthetics. The i-LIMB applies myoelectric technology, where the prefix myo- denotes a relationship to muscle. Myoelectric prostheses are controlled by placing muscle sensors against the skin at the site of amputation. The electric signals generated by the muscle at an amputee’s stump controls a processor aboard the prosthetic. This myoelectric technology allows for greater control and precision in the five fully functional digits, enabling recipients to perform everyday tasks such as picking up coins and opening tabbed aluminum cans.
5. Targeted Muscle Reinnervation
Amputees are in the infant stages of controlling prostheses directly with their minds. Through targeted muscle reinnervation, the nerves from the amputated limb are reenergized in a different part of the body, for example, the chest. When an amputee wants to use their arm in a particular fashion, he or she thinks the action, prompting the nerves in the chest to react. That reaction sends a message to a microprocessor in the robotic limb, which performs the action. Currently, there are only 35 people in the world with TMR limbs, and Blanck has fit 14 of them. He says the ever-changing prosthetic field aims to allow an amputee think about their prosthesis in a way that is normal. Jesse Sullivan (left) was the first man to receive this treatment technique from the Rehabilitation Institute of Chicago, and Claudia Mitchel (right) was the first woman to receive it.
After an amputation, most patients have a sensation that the limb is still attached and functional. It's known as phantom limb, and it's just one sign that the psychological adjustment to losing a limb can be as challenging as the physical adjustment.
In addition to phantom limb, those who lost legs in Monday's Boston Marathon attack may face post-traumatic stress disorder and grief as they adjust to a new normal.
"I always tell my patients that as hard as it is, it's a new reality, and the choices are to go into a dark room and close the door or confront the world in that new reality," said Dr. Alberto Esquenazi, chairman of Einstein Healthcare Network's Department of Physical Medicine and Rehabilitation and chief medical officer for MossRehab Medical Center in Pennsylvania, who is himself an amputee.
Often, doctors will hear new amputees say their lives are over. When Dr. Terrence Sheehan, Chief Medical Officer at Adventist Rehabilitation Hospital of Maryland and medical director of the Amputee Coalition hears that, he says, "Nope. It's changed, and we're going to help."
The rehab process involves a team of social workers, psychiatrists, physical therapists, occupational therapists, case managers and nurses. Often one of the most powerful visits in that early stage, Sheehan said, is from a new peer: a fellow amputee.
"When someone who has also lost a limb comes in and says, let me show you how to get back to life, that's when they can see what life's going to be," said Sheehan, referring specifically to the Amputee Coalition's peer visitation program.
And while runners may be able to handle the physical challenge of rehab and therapy, sometimes the emotional toll is hardest on people who perceive themselves as strong.
"It can take much longer for them to realize their new reality," Esquenazi said. "You can imagine that for someone who was running the race or had the ability to be there watching, in an instant their life changed. When you're confronted with that kind of life-changing event, it can be very challenging psychologically." Like those injured in war zones, many people who witnessed the scene at the Boston Marathon may face PTSD.
"The shock is wearing off," Dr. Joseph Shrand of Harvard Medical School said on New England Cable News. "Now the reality is setting in." Symptoms may include anger, fear, sadness, a sense of confusion -- at any time, in any order, he said. That's in addition to the steps of the grieving process that most new amputees go through, Esquenazi said: denial, why me?, blaming others ... and, finally, acceptance.
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When they do reach acceptance, patients can usually visualize what their life might be like. Life without a limb can mean a variety of different things to different people. For the elderly, it may be getting to live at home again. For a teenager, it may mean driving to the prom. For a runner, it may mean competing in another marathon. Much more is possible for amputees now than before 1990, Sheehan said.
"Before then, we might have said, OK, you're done with service, or you're done working. You're disabled," he said. "Now it's, get back on the plane, get back to climbing, running, jumping."
To runners, he'd say, "we have the technology to get you back to your sport."
In addition to, or perhaps because of, the advances in prosthetics that allowed Oscar Pistorius, the Blade Runner, to compete in the Olympics, and allows others to run marathons, people's perceptions have changed.
"People are much more comfortable showcasing their apparatus without qualms," Esquenazi said.
Jeff Glasbrenner, who has been an amputee since age 8, was finishing the marathon when the bombs went off.
"I wish I could reach out to the people who lost a leg," he told the New Republic. "I'd love to run a race with them."
Even with all the technology in the world, adjusting to life without a limb will be challenging. For many amputees, the sensation of a phantom limb never fully goes away, and some experience excruciating phantom limb pain. But experts suspect that people such as Glasbrenner may ease the transition.
"This is going to be a process -- it's not a single episode," Esquenazi said. "But with time, and in stages, they are going to succeed. We're going to stand behind them and try to help these individuals function at the highest level they can. They have the emotional support of the country behind them."