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As your second tour of duty in Iraq draws to an end, an insurgent's bomb explodes next to your convoy while en route to provide medical supplies to Iraqi children. You survive the attack and are sent home, missing a vital piece of your humanity; your right arm. You are fitted for an artificial arm while being treated at the Walter Reed Medical Center in Washington, DC. Countless hours turn into weeks as you adjust to the shock of not having a limb.
As physical therapy strengthens muscles, the metal hook attached to the prosthetic arm does not help your self-esteem. The mouth-watering hamburger you once enjoyed with both hands is being fed to you. Your toddler is afraid to hug you because you remind him of a villain he has seen in one of his cartoons. The rest of your family wallows in pity as they try to make sense of your condition.
With as many as 1,600 American soldiers returning home from war without the use of a crucial limb, a call to provide more humanized replacements is needed. The technology of artificial limbs, especially artificial arms and hands, has not changed since the Second World War. The basic hook is motorized so it can rotate, but prosthetic limbs are uncomfortable to wear. They generally become hot and sweaty and start to slip off. State-of-the-art prosthetics have three powered joints and do not provide much functionality. Unlike an actual arm that has 21 degrees of freedom, the hook and state-of-the-art prosthetic only provided three. Wearers are limited to the movement of the elbow, wrist, and the ability to open and close some type of hook. Because of this, most either continue using the hook and cable prosthetic or do not wear one at all. The simple task of picking up a water bottle or grape is a challenge for amputees who use both types of prosthetics. The ability to sense the density of an object is nearly impossible.
When asked by the Department of Defense to develop an advance prosthetic, Dean Kamen's reaction was a little less than enthusiastic. He said, "Look, you're nuts. That technology is just not available right now. And it can't be done. Not in an envelope of a human arm, with 21 degrees of freedom, from your shoulder to your fingertips." Dean Kamen, famously noted for inventing the Segway, holds more than 440 U.S. and foreign patents for innovation on medical devices. His devotion to medical innovation contributed to the invention of the first insulin pump for diabetics, called AutoSyringe. His company, DEKA (www.dekaresearch.com) is consistently developing new advancements for medical technology. With the U.S. Department of Defense's funding and support (www.darpa.mil), Kamen's goal is to create a prosthetic as close to a real arm as possible.
In as little as 13 months, Kamen and his team have been able to use the latest technological advancements to build a fully functional robotic arm. From something out of a Sci-Fi movie, 'Luke' as it's referred to, has 14 out of the 21 degrees of freedom. The device, which weighs 6.9 lbs is made of aluminum and designed small enough to fit on a 50th percentile female. This was done to ensure that it would fit on anyone despite his or her level of amputation. The precise motor control is due to the set of 14 actuators. Actuators are mechanical devices for moving or controlling a mechanism or system. Actuators take energy like air, electric or liquid and convert them into motion. Each of the actuators has its own capability to sense temperature and pressure. This is what allows the wearer to pick up a grape or water bottle without crushing it. The pneumatic cuff holds the arm into place to allow its user to put them self under heavy load. The more they do this, the more it attaches itself to the wearer. Kamen hopes the final arm will look like an exact mirror image of the wearer's other arm. This will be done using silicon rubber rubber, coated and painted to look 3D.
Pending approval from the FDA, the DEKA arm is expected to be available at a cost of upwards to $100,000. This price is actually comparable to what today's state-of-the-art prosthetic costs. Currently the prototypes of the initial arm are undergoing testing in human clinical trials. Dr. COL Geoffrey Ling M.D., Ph.D. who is the program's director says the arm will be available for clinical trials in about two years. He predicts in about four years to further improve on the prosthetic, and produce a device that will be directly controlled by neural signals. This will be done by a surgical procedure re-routing the residual nerves of amputees. The nerves will be moved out of the armpit to under the clavicle, connecting them to the pectoral muscles. When the wearer thinks about moving their arm, the signal will travel down to the nerves into the chest. When the muscles contract, the electrodes in the chest will send a signal to the prosthetic arm, moving the arm.
As the conflict in the Middle East continues, we will unfortunately see more and more American soldiers coming home without limbs. Putting technological advancements to positive use like this will enable many American War Veterans to have as normal as a life as possible.
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