Prsthtcs

Everything you need to know about prosthetics

The field of prosthetics that enhances mobility and communication is indeed growing and evolving to develop devices that mimic natural body functions. It is in some way a form of evolution that humans are beginning to undertake - short of self-regenerating limbs - and bringing function back where it has been lost.

Upper-limb prosthetic technology has undergone little innovation since World War 2; however, with the growing number of amputees as a result of war and the impetus of brain-machine technology, the field is on the brink of revolution. Prosthetics once hoped to give patients merely a vestige of the functionality they once had. Now, the goals are much grander: upper-limb prosthetics hope to give patients functionality that rivals that of natural limbs, sensory feedback to create “feeling,” and comfort. Many new prosthetics are being developed with these goals in mind; however, this blog has concentrated on three: DARPA’s Proto-2, Tel Aviv University’s SmartHand, and University of Michigan’s biological scaffold. With these technologies, the field of upper-limb prosthetics is about to transform into a field that gives patients the functionality of a natural limb so as to minimize the changes in quality of life suffered due to amputation.

Several caveats exist with these technologies; with the Proto-2 and the SmartHand, invasive surgery is needed to establish the brain-machine interface. One wonders whether patients will be able to handle another invasive surgery after amputation or if insurance companies will cover the costs of both the prosthetic and the surgery. Although the biological scaffold may limit the need for invasive surgery as it creates an artificial neuromuscular junction at the site of amputation through tissue engineering, the scaffold poses its own risk of tumors. Given the overwhelming promise of these technologies and the tremendous increase in quality of life that they promise, the only major foreseeable obstacle would be whether these technologies are covered by insurance companies. One must wonder whether the technology will become standard of care for all patients or just veterans and the privileged.

Inventions like the MIT ankle-foot, K3 Promoter and the brain computer interface system have been great leaps forward in their fields and have shaped the development of prosthetics. They have also paved the way for greater impact outside of the less-abled and change the way we work and play with mind-control software that may one day allow us to efficiently perform tasks and reduce our dependence on one’s physical attributes.

Prosthetics, in every form, holds the promise of re-enabling the bodies of debilitated individuals.  When it comes to athletes, who depend on the functionality and efficiency of their bodies to perform, prosthetics promises them the continuation of their passions.  Today, it is not uncommon to hear that a single-arm amputee not only patented a better prosthetic arm, but also surmount one of the world’s tallest mountains single-handedly (no pun intended!).  In double-amputee Oscar Pistorius’ case, his prosthetic limbs enable him to compete in professional-level races, even without natural legs.  Today, he continues striving for his dream of competing in the 2012 Olympics, despite the Olympic Council’s determination to prevent him from participating.

This also bring up an important element to the realm of prosthetics—controversy over the enabling properties of artificial limbs.  In Oscar Pistorius’ case, the Olympic Council argued that his limbs gave him an unfair advantage over his competitors.  This remains the case throughout Paralympic athletes—disabled athletes wanting to compete among the able-bodied.   While this fight is obviously still being fought vigorously on both sides, it remains to be seen if athletes like Oscar Pistorius have the possibility of attaining the elusive Olympic gold. As with any changing technology, controversy immediately becomes part of the picture.

For prosthetics, one area of biotechnology that has taken decades to adapt, controversy is not only considered part of the equation but also welcomed by many amputees and recipients of fake limbs. In other words, it’s about time. Sports, healthcare, the fashion industry, etc. are all places where prosthetics have a positive effect of the perception of disabled and their needs.  Aimee Mullins, a model and public speaker with both legs amputated asks, “What defines beauty?” For the health insurance, the prominent debate has become, “What technology is necessary to function in society? Is there a difference (to health insurers) between a hook and a SmartHand?” But if ever, now is the time for the debate t o rage on. As long as controversy allows for open discussion, in a society that continually seeks to redefine itself according to the latest politics, the topic of prosthetics will gain consideration among medical and social communities alike.

There is no doubt that growing full body parts to replace lost ones will be commonplace in the future as it already has been proven possible. These parts may bring far more ethical debates than mechanical ones but I believe that is the future of prosthetics and it is only a matter of time that we get there.

Feeling the way

Robotic device developed in MIT’s Touch Lab can help visually impaired people navigate around a virtual model of a real building.

Google Maps and other GPS navigation devices might be great advances to most people, but for the legally blind, they’re of little help.

Researchers in MIT’s Touch Lab have developed BlindAid, a system that helps the visually impaired “feel” their way around a virtual model of a room or building so they can familiarize themselves with an environment before entering it.

The BlindAid system builds on a device called the Phantom, developed at MIT in the early 1990s and built for production by SensAble Technologies. Phantom is effectively a robotic arm that the user grasps like a stylus which can create the sensation of touch by exerting small, precisely controlled force on the user’s fingers.

Flash forward to BlindAid. The BlindAid stylus functions like a blind person’s cane, allowing the user to “feel” virtual floors, walls, doors and other objects. The stylus is hooked up to a computer programmed with a three-dimensional map of the room. When a virtual obstacle is encountered, the stylus produces force against the user’s hand.

Mandayam Srinivasan, the Touch Lab’s director, is working with the Carroll Center for the Blind in Newton, Mass., to develop and test the device. It’s been tested on 10 visually impaired subjects at the Carroll Center.

One of the toughest challenges for the visually impaired is entering an unfamiliar environment without guidance. According to preliminary results, participants had an easier time navigating around an actual room if they could preview a virtual model of it.

Environments best suited for the device include public transportation lines and public spaces such as museums or train stations.

The device does require a bit of training, however. To achieve success, the user must have “a well-developed sense of space.”

BlindAid can also help mobility instructors evaluate feedback for how successfully the user is exploring their environment and where trouble spots persist.

Former postdoctoral associate Orly Lahav and research scientist David Schloerb were behind much of the device’s development.

Let ‘em Play!

If you asked the average Brown student if he or she could draw a fine line between prosthetics and non-prosthetics, 99 times out of a 100 the student would probably be able to give you a straight answer.  However, under closer scrutiny, that “fine line” is actually pretty blurry, and, among some experts, either completely arbitrary or absent altogether.

The reasoning is this: the dictionary defines prosthetics as “a device, either external or implanted, that substitutes for or supplements a missing or defective part of the body.”  Sure, that could mean the osteo-integrated left leg of a handicapped runner, or it could be something as simple as a swim cap—by “supplementing” a swimmers non-hydrodynamic head.  Or, for instance, Speedo’s new LZR Racer, which makes a swimmer more buoyant. According to a related article, “since the suit was introduced, records have fallen like rocks in a landslide, but the sport’s governing body decided it was legal.”

Returning to the topic of my previous blog post on Oscar Pistorius, a Paralympics runner who dreams of competing in the 2012 London Olympics, I question why it is he is barred from participation, despite the studies that have shown that his prosthetic legs give him a disadvantage to other runners, rather than the hypothesized advantage that Olympic officials reasoned in previous years.  How do we draw the distinction between a substance like HGH (Human Growth Hormone) and Creatine; titanium rods under the skin and prosthetic legs; or Nike’s carbon-sole-enhanced shoes and Oscar’s carbon tibiae?

Such arguments, though not nearly as popular as a steroid scandal or blood doping, are prevalent in today’s competitive society—and many athletes have taken advantage for the lack of a fine line between what is allowable and what is not.  Upon losing his 18^th straight competitive tournament, Tiger Woods opted for LASIK eye surgery to correct his eyes, one more so than the other.  With 15/20 vision, beyond a normal human’s 20/20 vision, gives Tiger the ability to see the green and flagpole with crisper and clearer precision.  Another case is the Indianapolis Colt’s undersized receiver Anthony Gonzalez, who sleeps in a hyperbaric chamber to saturate his blood with oxygen and gain fourth-quarter stamina.

Where do we draw the line?  And will there be a day when we no longer shed tears for a “disabled” person, but rather that they may take pity on us “healthy” human beings?

Feel free to leave your views and conclusions in the comment area!

-Richard

<http://sports.espn.go.com/espnmag/story?id=3357051>

Augmented Champions

Imagine an athlete whose debilitating injury (whether permanent or temporary) bars him or her from participating in a sport.  Imagine their frustration and anxiety as they run familiar plays in their heads, replaying some of their most glorious moments, or watch their teammates and other competitors play.  I know I’ve experienced these kinds of injuries before, but never on a serious level—more along the lines of a twisted ankle.  Compared to what unfortunate accidents have happened across the sporting world, my previous injuries have been superficial at best, even ignorable.

Now imagine the traumatic injuries that involve amputation of athletes’ limbs, none of which can be considered “superficial” or “ignorable.”  Following surgery and rehabilitation, it would seem pseudo-miraculous for them to continue to pursue their dreams with renewed vigor.  Such is the story of four unique athletes, as magazine Popsci chronicles the continuing tale of super-athletes who have made a name for themselves in the prosthetic world.

Number one is double-leg-amputee climber Warren Macdonald, who is equipped with two spring-loaded titanium legs that span from foot to mid-thigh, propelling him step-by-step up Africa’s tallest mountain, Mount Kilimanjaro, and, in the near future, Africa’s second-tallest mountain, Mount Kenya.  Number two is Aron Ralston, whose name is commonly known among amputees.  Pinned for five days under the weight of a multi-ton boulder in Utah’s Blue John Canyon, Ralston courageously self-amputated his arm below the elbow to free himself—with a pocket knife.  Now if that is too big of a pill for you to swallow, imagine seeing him rock climbing again in a year, this time assisted with a self-designed aluminum attachment that helps him grip against rock surfaces (and should he face the unfortunate situation of having to forcibly remove his prosthetic hand, there is an additional feature that allows him to “eject” the arm with the push of a button).  The third and final segment involves professional mountain biker, Will Craig, and his self-patented Fox Racing Shox compression elbow.  Able to flex, rotate, and shift gears, despite the varying inclines on mountains, the compression elbow is also equipped with shock-absorbent mechanisms, much like those on conventional mountain bikes, to ease the impact on the shoulder.

While these new prosthetics do enable these athletes to continue their passions, it is important to note that the cold, metallic combination of wire, titanium, and polymers is by no means an equal substitute to actual limbs; in fact, prosthetic athletes must undergo additional training and fitness simply to perform.  But by sheer competitive will and determination, these athletes are still able to engage in their favorite activities.

It makes me wonder, actually, how long it will be before prosthetic technologies progress into the field of having internal robotics and nano-sensory mechanisms to better assist the disabled.  And this also begs the question of the ethics in competitive sports, and whether the augmenting technologies of prosthetics give these athletes an edge over their athletic counterparts.  For more information about this debate, please refer to my next blog post – “Let ‘em Play”.

-Richard

<http://www.popsci.com/node/9171>

The Hook Handed Man vs. The (Hand) Handed Man

Consider Captain Hook. This fictional character from the Peter Pan fantasy has no hands, and yet his hooks prove versatile to allow him to eat and function as best he can. Though he has limited ability, his evil antics would be far more limited with a prosthetic that resembles a hand and has no mobility. For many years, this situation was not as fictional as many amputees would have wished. The controversy between form and functionality in prosthetics is ages old, and is only now beginning to achieve some sort of compromise in the prosthetic world.

No longer will most people missing limbs have to settle for a hook. However, most prosthetics available that function best have achieved some resemblance to an arm, but remain obviously distanced and separate from normal-looking arms. According to Dudley S. Childress, director of Northwestern University Prosthetics Research Laboratory, compares prosthetics design to architecture (http://www.rehab.research.va.gov/jour/75/12/1/childressed.pdf). He explains that, “The motto “less is more,” of the Chicago architect Ludwig Mies van der Rohe, would seem appropriate for consideration and practice by many designers of prostheses. Frank Lloyd Wright’s concept of “organic architecture” also seems applicable in prosthetic design.” He considers the best designs those that most resemble ordinary, healthy hands first, and consider how they work second.

In many respects, the field of prosthetics has changed dramatically over recent years. One need only view the SmartHand,” developed by the Tel Aviv University and DARPA’s Proto-2 prosthetic (see Lakir’s articles) to appreciate the consolidation of design and device. Yet these hands still are far from release to the average individual in need of a replacement hand.

One must also consider that the fake hands that most appear normal still have the least amount of personal control. In terms of everyday living, one must weigh whether, for example, when going to the grocery store they would prefer to pick up fruit and vegetables with both hands (and receive prolonged stares and perhaps offers of assistance), or one handedly with little extra attention.  Hopefully, compromise between form and function will continue to be made (Though it may be too late to assist Captain Hook).   

-Karin

With a greater spring in your step

If something were to happen to you tomorrow - a debilitating accident or the sudden onset of a degenerative disease you never knew you had - what would you do? How would you feel? These thoughts came to my mind as I went about researching the topic of prosthetics. These mechanical devices had little to do with me right now, but I what if I needed them to help me lead a normal life somewhere down the road? As an athlete who grew up with sports as an integral part of my life, I wonder how I’d take the news that I would never walk or see, never mind running or cycling. There is a breed of heroes amongst us, people who transform lives that have been seemingly destroyed, and MIT Media Lab Professor Hugh Herr and his team are part of this breed.

They developed the ankle-foot, aptly named after the body part it seeks to replace. Perhaps emulate is a better word, since it strives to give amputees the spring in their step back. The ankle-foot propels users forward using tendon-like springs and an electric motor. It reduces fatigue, improves balance and provides amputees with a more fluid gait than they would have with their conventional passive-elastic prosthesis. The prosthesis is capable of propelling the wearer forward and varying its stiffness over terrains, successfully mimicking the action of a biological ankle.

An below-knee amputee walking with the powered ankle-foot prosthesis

Looking at the video above, it is evident how normally the patient walks and has regained most, if not all normal walking function of the foot. There is no doubt that an invention such as this will dramatically improve the lives of many amputees still moving around in wheelchairs or using conventional prostheses that offer little flexibility or even adaptation to the terrain like the natural foot does.

“With 26 bones, 35 joints, and the awesome responsibilities of weight-bearing and propulsion, the foot is one of the trickiest body parts to mimic. Today, amputees must choose between mechanical models, which rely on flat carbon-fiber platforms that bend slightly with each step, or a computer-controlled motorized foot that better reproduces a natural gait but can cost up to $18,000 and often isn’t covered by insurance.” [1] This is where Gordon Link, a diabetic and foot amputee, hopes to bridge that gap with the K3 Promoter which mimics the jointed motion of a real foot for easier walking.

While these technologies are developed and tested, the collaboration across fields will help expedite the process of bringing them to market and give the ability to walk back amputees. The way forward will be osseointegration - directly joining these devices to human bone at the extremities of the amputation, leading to efficient energy transfer, increased comfort as well as control.

It’s only a matter of time that these inventions begin to touch the lives of millions out there waiting to regain their place in the world.

- Yan Liang

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[1] PopSci: The Natural Artificial Foot

Another revolutionary foot prosthetic: Proprio Foot

Harnessing The Power of the Brain

Prosthetics play a significant role in the lives of many, helping people walk, eat and go about their lives as close to normalcy as possible. But few of them bring back what arguably is the most important part of being human, the ability to communicate with others. The brain–computer interface (BCI) gives people this ability, and what a feeling it must be to be able to reach outside a trapped body. So much so that Scott Mackler - a husband, father and neuroscientist at the University of Pennsylvania who was stricken with ALS, Lou Gehrig’s disease, decided to live on despite not intending to do so when he received the news at age 40. He has since progressed from communicating with primitive stares to being able to continue his research in the laboratory and speak with his loved ones in whole sentences.

This technological advancement has paved the way for controlling all sorts of implements with only one’s mind, be it a body part prosthetic which can operate at one’s command or to communicate with computers. Interestingly or ironically, what struck me about the video was the research done on monkeys. It probably was because of how visual this result was as compared to the seemingly slow (though just as successful) ability of people to choose characters to convey their thoughts. Researchers are now able to decode brain activity in monkeys and use devices to reproduce their movements in robotic arms. Monkeys have advanced reaching and grasping abilities and good hand manipulation skills, making them ideal test subjects for this kind of work. It definitely won’t be a stretch for a human being to make such progress as well.

The use of monkeys as test subjects - introducing electrodes into the brain to pick up brain impulses - and drilling holes in their skulls does invoke feelings of sympathy and possibly anger in many animal-lovers. It was also rather disconcerting to see that the connection between the brain and the wires connected to the computer were not shown (whether it was on purpose, is debatable) during the video. Most viewers may not pick up on this but I think that this is a point of contention amongst animal lovers and the scientific community in general. How far will be push scientific research for the eventual benefit of humans at the expense of animals?

For better or for worse, man’s hubris has led to a significant result by all counts. As evidenced by the number of posts by the loved-ones of people with debilitating illnesses at the end of the article, this invention comes as a beacon of light for husbands, wives, children and parents around the world who may have lost all hope. It is only a matter of time that the technology progresses from the selection of letters on a computer to forming full sentences in real-time and having it voiced out by speakers. It also leads me to think about the possibilities that this may bring to the perfectly healthy people like you and I, and I will speak about this on my next post.

- Yan Liang

CBS Article: Harnessing The Power Of The Brain

Bringing Them to the Street

In my last installment, I’d like to talk about how some cutting-edge technologies are making a real impact on the lives of people today, as opposed some of those previously mentioned that would take some time to reach the mass market. Take it as a mini tech review if you will. Also I would like to extrapolate how these technologies could become spin-offs that help to simplify and change the way we work and play.

The Chariot

In short, this as a Segway controlled by body movements.

It is remarkable how body sensors are able to pick up the slightest changes in muscle movements in the lower torso and hips and translate them into near flawless control of the chariot, yet another product of interdisciplinary collaboration. I can even imagine able-bodied people traveling around on these as a new mode of transport (yes there’s no end to how lazy we can get).

Reading your Mind - Emotive’s EPOC & NeuroSky’s MindSet

It looks like a mind control cap from a sci-fi movie, but in fact, it’s a mind-controlled game controller.

The headset is constructed of 16 nodes spaced around the head that detect the EEG patterns emitted by your brain, which are then processed and recognized. Unlike regular EEG scans that require the electrodes to be glued directly to your head, Emotiv has a “patented material” that lets the nodes simply rest against your skull with no adhesive required. You have to train the headset to recognize what kind of thought pattern equates to a certain action. Thoughts picked up by the headset include moods and feelings as well, as your brain signals your muscles to perform certain actions.

These headsets run alongside those developed by researchers in neuroscience laboratories and seem to be the ones bridging the gap and making it affordable for everyone. The application to all other fields are endless, robots that can take over dangerous work, robotic wheelchairs (video below) automatic typing of college papers on your computer…(yes I’m waiting for this). This also opens up possibilities for employment of the less-abled in places they would never get a job and leveling the playing field for this group of people.

With these medical technologies filtering out to mainstream users, we’re seeing the beginning of a transformation of the way we live, work and play. What’s not to like about it?

- Yan Liang

“You’re so Beautiful, You Don’t Look Disabled” (Told to Aimee Mullins by a fashion designer)

Aimee Mullins defines herself as a model, athlete, actress and motivational speaker. She hates to be called “inspirational”, because that sounds to her like she doesn’t have talent. And for someone missing both legs, talent must have been involved in her accomplishments, as well as strength and determination. But Aimee Mullins’ story brings up several hotly-debated issues surrounding social perception around people with prosthetics, according an interview with New Scientist. The first of these controversies her family had to face before Aimee herself could talk.

About one in 2,000 children is born with some form of limb deficiency, according to the National Center for Health Statistics. The parents of baby amputees are faced with a wide range of options and opinions for their growing and disabled child. Specially, when (or if) to start the use of prosthetics, and what type of arm/leg replacement to use. Several different types include myoelectric, body powered, and passive. A recent study by The Association of Children’s Prosthetics-Orthotic Clinics determined that the best age to introduce prosthetics was before 2.5 years of age, but that depended on the comfort and function of the prosthetic. Born without fibula bones, Mullins had both of her legs removed before she turned one, and started using prosthetics soon after.

She compares her legs to the use of titanium hips and contact lenses; as aiding in utility, not changing her as a person. In fact, Mullins has twelve pairs of legs. She explains, “I was intrigued by the imaginary visual of a different version of myself, and I suspect it provided something tangible when asked if now, at this point in my life, I would trade my prosthetics for flesh and bone legs. (I wouldn’t).” Like many people with prosthetics, she’s frustrated at the perception of disability before capability. “It’s the society that disables the individual,” is her belief. Aimee Mullins eventually concedes that society is changing, though slowly. A recent court case over discrimination in the workplace, settled in August, may effectively prove her point. The BBC reports the experience of a woman, “Miss Riam Dean (22)…who was forced to work in the stockroom (of Abercrombie and Fitch) after wearing a cardigan to cover her prosthetic arm”. The store employers evidently felt that she did not fit the image the store wished to project. Miss Dean was awarded her £8,000 for “unlawful harassment”, but the court concluded that her case “can not be characterized (as) direct disability discrimination.”

For Mullins, the difference between augmentation and prosthetics is a matter of taste and functionality. She cites cosmetic surgery and Tiger Wood’s eye correction. As a professional athlete, she broke world records at the 1996 Paralympic games in Atlanta, Georgia. To her, the boundaries between society for the able bodied and those with separable limbs are just as breakable. Needless to say, Mullins’ journey has not been the usual experience of an amputee. But with her guidance, perhaps others will find the way to acceptance an easier route. And maybe as a society, we’ll figure out what exactly ability means.

How Much Is Your Leg Worth to Your Insurance Company?

The Health Care debate in Congress has brought national attention to health insurance and coverage. But one area that doesn’t appear regularly in disputes involves prosthetics – and who pays for them. It’s no secret that a fake arm or a leg can cost, well, an arm or a leg. Most models typically cost $10,000 to $25,000, with newer and more effective prosthetics such as the iLimb ranging from $50,000 to $80,000. These estimations also fail to address expenses for therapy and limbs wearing out. Nine states have adopted policies mandating coverage of prosthetics and braces deemed medically necessary. Now, a bill introduced to the House of Representatives last May aims to provide coverage nationally.

According to the Library of Congress, the Prosthetic and Custom Orthotic Parity Act of 2009 (HR 2575 IH) seeks to offer “parity under group health plans and group health insurance coverage in the provision of benefits for prosthetic devices and orthotics devices, components and benefits for other medical and surgical services” (http://thomas.loc.gov/cgi-bin/query/z?c111:H.R.2575:). In other words, a comprehensive plan that allows for the most appropriate model, as well as benefits to cover repairs and replacements. If passed, the bill would raise premiums, but shouldn’t exceed more than 25 cents a month for most customers, as cited by a recent Bureau of Insurance study.

Tricare and Medicare already offer $18,000 to those who qualify for state and federal aid. However, private medical insurers usually have a low annual cap for prosthetics, which amounts to about $2,000 in total. For many of the 1,800,000 people in the United States living with limb loss, and thousands of military personnel losing limbs amidst conflict, $2,000 just won’t be enough to make prosthetics a possibility. With diabetes on the rise, more complications such as loss of limbs are expected to increase among patients in the not-so-distant future. For an amputee to regain confidence and become, as the bill terms it, “a functioning member of society,” a good, comfortable, and most importantly affordable prosthetic becomes a requirement. Gaining a replacement limb should allow someone to get their life back and not have to sink into financial ruin.

As of October 22, the bill has been referred to the Subcommittee on Health, Employment, Labor, and Pensions. It should have a substantial shot at passing, but as with all health-care related policies currently falling into the legislative branch, patience is required.

- Karin

Oscar Pistorius: Courage Today, Success Tomorrow

Interactive flash: The Cheetah Prosthetic

More often than not, the traumatic experience of limb amputation and the life-altering effects of prosthetics dependency are enough to occupy a human being for a lifetime.  In addition, it is not uncommon (it usually expected, in fact) for the disabled to be detracted from the activities of those who are fully able.  Such is not the case of South African Paralympic runner Oscar Pistorius, whose debilitating birth defect to his legs caused him to need major surgery—the amputation of both his legs between knee and ankle before his first birthday.  Today, at the age of twenty-one, Oscar trains day to day on the track and in the gym, dreaming of taking his name to the 2012 London Olympics.  His coach, Ampie Louw, affectionately describes Oscar as “a five-speed engine with no second gear.”

How does Oscar “get around”?  Well, for one, he certainly gets around fast, thanks to the prosthetic limbs provided to him by Icelandic company Ossur.  His “bionic” legs, called “Cheetah Flex-Foot”, are J-shaped, carbon-fiber-constructed artificial limbs that bend like springs, propelling Oscar forward as he runs.  Most recently, he took the gold medals in the 100-, 200-, and 400-meter sprints at the 2008 Summer Paralympics and aiming to “take a hell of a lot more” next time around.

It is also these prosthetic limbs that have been the spark of controversy in the Olympic qualifying rules.  Olympic qualifying officials argued that Oscar’s prosthetic limbs gave him an unfair advantage compared to his competitors with natural limbs.  Experts currently “say there have been limited scientific studies on the biomechanics of amputee runners, especially those missing both legs”, and Oscar has the unique case of being amputated during early childhood, unlike the traditional accident-based injuries.  However, Oscar does have another three years, and while his times may slowly approach the Olympic-qualifying level, perhaps within the same time period studies will finally convince the Olympic committees to admit him into the upcoming summer Olympics.  For now, all Oscar can really do is run faster and train faster.

On a broader scale, Oscar’s prosthetic legs begs the question, “Where should limits be placed on technology to balance fair play with the right to compete?”  The controversy that surrounds the bioenhancement and augmentation of amputees certainly asks for some form of guideline and objective measurement, but it seems that, at least for now, disabled athletes are can only compete in the Paralympics.  However, I imagine that Oscar’s story is one of many to come, and that one day in the future athletes, Paralympic or not, may race against each other on the track.

Throughout his life, Oscar has been described to be undaunted by his disabled condition.  In fact, he doesn’t even call his lack of lower limbs a disability: “You’re not disabled by the disabilities you have, you are able by the abilities you have.”  Nicely said.

Oscar Pistorius, I have two words for you: Run on!

- Richard

Biological Scaffold Improves Nerve-Muscle Connection for Prostheses

Researchers at the University of Michigan have used tissue engineering to improve the function of prosthetic hands, ScienceDaily reported on October 17^th, 2009. Like others, the article speaks of a need to overcome the shortcomings of current prosthetics; specifically, to create a prosthetic that moves like a normal hand while remaining comfortable for the patient. Whereas DARPA’s Proto-2 prosthetic and UTA’s “SmartHand” use targeted muscle reinnervation to recreate neuromuscular connections with the residual nerves at the side of amputation, the University of Michigan has created a biological scaffold of muscle cells and a nano-sized polymer that will effectively create an “artificial neuromuscular junction”[1]. Since the scaffold can be placed over the severed nerve endings like a sleeve, it appears that surgery would be as invasive as targeted muscle reinnervation. As noted in earlier posts, the invasive surgery needed to implement DARPA’s prosthetic and the “SmartHand” may not only deter patients from the technology but might also complicate the extent to which insurance covers the costs.

The article explains the biological process that takes place:

“The muscle cells on the scaffold and in the body bonded and the body’s native nerve sprouts fed electrical impulses into the tissue, creating a stable nerve-muscle connection”[1].

Although in vivo interactions and reaction are an issue with tissue muscle reinnervation, tissue engineering poses even more of a risk because growth could lead to tumors.  Paul S. Cederna, M.D., a plastic and reconstructive surgeon at U-M Health System, has stated that “the nerve does not grow an abnormal mass of nerve fibers”[1]; however, the potential of abnormal growth should remain a issue throughout clinical trials.

Enabling patients to experience the sensations of touch and temperature is the goal of sensory feedback prosthetics. The University of Michigan’s biological scaffold conforms to that goal as the artificial neuromuscular junction allows for greater motor control of prostheses and allows for sensory feedback of touch and temperature. Thus, the scaffold could be integral in making prostheses like the Proto-2 and the “SmartHand” more feasible and effective.

The research team working on the scaffold has submitted a proposal to DARPA to being human trials in three years. Although DARPA has been effective in centralizing the development of prostheses, one must question who will first receive the benefit of such technologies if DARPA holds a monopoly: the regular injured patient, a veteran, or (hopefully) both?

In terms of healthcare and health insurance, the “artificial neuromuscular junction” technology can only improve the chances that more technologically advanced prostheses are covered by insurance companies: the scaffold creates an alternative for the more surgically invasive targeted muscle reinnervation technique. Thus, overall costs of these new prostheses could be lowered. As stated earlier, however, the potential for abnormal growth will remain a risk until clinical trials prove otherwise.

- lakir

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[1] University of Michigan Health System (2009, October 17). Bioengineering Of Nerve-muscle Connection Could Improve Hand Use For Wounded Soldiers. ScienceDaily. Retrieved November 14, 2009, from http://www.sciencedaily.com/releases/2009/10/091014122043.htm

“SmartHand” links mind and machine to give “feeling”

On November 5th, 2009, ScienceDaily reported that Tel Aviv University has developed a new prosthetic, “SmartHand,” which closely emulates a real hand in terms of function, sensitivity, and appearance. The basis of the “SmartHand” is similar to that of DARPA’s Proto-2: an interface between the residual nerves in the arm and the device’s electronics.  The combination of prosthetics with neural interfaces allows users to manipulate devices with solely “intention,” just as they would a natural limb. The article reports that:

“Robin af Ekenstam of Sweden, the project’s first human subject, has not only been able to complete extremely complicated tasks like eating and writing, he reports he is also able to “feel” his fingers once again”[1].

Given the similarities between the “SmartHand” and DARPA’s Proto-2, the article explains technologies that have already been elucidated; however, some important issues are raised. Since these “sensory feedback” prosthetics require implantation of surface electrodes, one must question the longevity of the technology. Professor Shacham-Diamand, the leading researcher on the TAU team, comments that the team’s challenge “was to make an electrode that was not only flexible, but could be implanted in the human body and function properly for at least 20 years”[1]. Since function of the prosthetic would rest entirely on the ability of the surface electrodes to translate neural signals into mechanical movement, longevity and durability becomes extremely important. Without extensiveclinical trials, it is currently difficult to assess the viability of the electrodes being used. Patients and researchers must wonder what would happen if the electrodes were to fail and their prosthetic were rendered inept. If further invasive surgery is needed to fix any problems that may arise with the electrodes, patients may need to weigh the benefits of devices such as the “SmartHand” with the serious risks.

Although current models of the “SmartHand” appear bionic, the team intends to develop an artificial skin for the prosthetic. The potential for a prosthetic that not only functions like a natural hand but appears like one provides a positive outlook for the field of upper-extremity prosthetics. In addition to providing aesthetics, artificial skins would also improve the prosthetic’s sensitivity to touch, feeling, and temperature, giving patients an experience that will undoubtedly be hard to distinguish from “the real thing.” Given the promise for such life-changing technologies, the benefits of prosthetics like the “SmartHand” may outweigh risks such as potential for electrode failure and surgical repair.

Whereas the prosthetics that DARPA is developing are primarily intended for veterans, the “SmartHand,” developed by the Tel Aviv University, appears to have common patients in mind. As more and more private institutions develop prosthetics similar to “SmartHand” and DARPA’s Proto-2, potential access for the average amputee patient will increase. Additionally, the advent of competition in the realm of sensory feedback prosthetics may result in the technology being covered by health insurance. However, as predicted with the DARPA Proto-2, the costs of surgery for the implantation of the electrodes and the implied costs of any subsequent surgeries for repair may influence the way insurance companies handle prosthetics. Since the “SmartHand” is the product of a European institution, it will be interesting to track the access of costs of sensory feedback prosthetics in several European health care systems, some of which are government-run, and how that will impact access in the United States.

-lakir

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[1]American Friends of Tel Aviv University (2009, November 5). Applause For The SmartHand: Human-machine Interface Is Essential Link In Groundbreaking Prosthetic Hand. ScienceDaily. Retrieved November 14, 2009, from http://www.sciencedaily.com/releases/2009/11/091104132708.htm

Image reproduced from [1]