Nearly two-million Americans are living without a limb. There have been several advances in lower limb prosthetics in recent years, but upper limb devices haven’t changed much. Now, researchers are studying a bionic hand that could revolutionize the way wounded soldiers move.
Seven years ago, Army Sergeant First Class, Ramon Padilla Munguia lost his hand, and almost his life, in Afghanistan.
“Every morning, I thank God that I’m still here,” Munguia told Ivanhoe.
Now, Munguia is using a bionic hand. He’s the second person in the world to test the new prosthetic.
Using this IMES system, Munguia has eight tiny sensors implanted on muscles inside his arm. As he contracts his muscles, the electrodes pick up the signal and transmit it to the prosthesis, which moves accordingly.
“Now, if I want to close the hand, all I got to do is this movement and I do this movement and the hand closes,” Munguia explains.
Current motorized hand prostheses use surface electrodes that are placed over the skin and only allow limited motion.
“So, we thought if we could put electrodes underneath the skin and put them into the muscles directly, we’d have a lot better control,” Paul F. Pasquina, MD, Uniformed Services University of the Health Sciences, told Ivanhoe.
Munguia can rotate, bend and move his hand and fingers in different directions.
He’s even learned to play golf with his new prosthetic.
“It’s a wonderful game, and it’s a beautiful game. This gives me a brand new incentive to do well,” Mungia said.
A new hand and a new found hobby for a man who won’t let anything hold him back.
The prosthetic system is controlled by implantable myoelectric sensors, or IMES for short.
Alfred Mann Foundation’s researchers at Walter Reed are currently conducting a feasibility study and hope to enroll a third patient soon.
BACKGROUND: According to the Amputee Coalition, there are about 2-million people in the United States living without a limb. Close to 185 thousand amputations occur each year. The main causes are diabetes and peripheral arterial disease. Research shows African Americans are up to four times more likely to have an amputation than white Americans. Some amputees may have phantom pain. This is the feeling of pain in the missing limb. If an artificial limb is worn there can be surgical complications and skin problems. Usually physical therapy can help people adjust. (Source:
TREATMENT: Motorized hand prosthetics are being used by some people. These prosthetics use surface electrodes that are placed over the skin, but only allow limited motion. The external myoelectric prosthetic in some cases, has been unreliable and constricting. Doctors have seen a high abandonment rate among users. New limb replantation is also an option. Some techniques have been successful, but incomplete nerve regeneration is a major limiting factor, according to the National Institutes of Health. Usually the patient has a better outcome if they are fit with a functional prosthesis.
(Source: http://www.nlm.nih.gov/medlineplus/ency/article/000006.htm; http://www.nlm.nih.gov/medlineplus/limbloss.html; http://www.militarytimes.com/article/20140208/NEWS04/302080003/EOD-Marine-first-receive-revolutionary-prosthetic-implant)
NEW TECHNOLOGY: What's being called the “bionic hand” is now being used by some patients. The implantable myoelectric sensor system, or IMES for shot, helps amputees have better control of their prosthetic. Tiny sensors, the size of rice grains, are implanted on the remaining muscles inside the arm. As the muscles contract, electrodes pick up the signal and transmit it to the prosthesis. The prosthesis can rotate and bend. The hand and fingers can also move in different directions. The implantable sensors tap into a wider variety of muscles with stronger signals from the muscle within. For more information on this advanced technology, visit the Alfred Mann Foundation at www.aemf.org, the developer of the IMES system, where work on some of the most challenging medical problems have been taking place for over a quarter of a century. Also, for more information on where Dr. Paul F. Pasquina performs his research, visit www.usuhs.mil, Uniformed Services University of the Health Sciences.
FOR MORE INFORMATION, PLEASE CONTACT:
Paul F. Pasquina, MD
Uniformed Services University of the Health Sciences
Phone: (301) 295-6885
Paul F. Pasquina, MD, Uniformed Services University of the Health Sciences talks about implantable sensors that control a prosthetic hand, which could revolutionize the way wounded soldiers move.
What makes this new hand different?
Dr. Pasquina: When we started taking care of combat causalities returning from Iraq and Afghanistan back in 2003, we saw a large number of injured service members with major limb loss and by major limb loss, wrist and above or foot and above. What made our combat casualties much different than the folks with limb loss in civilian settings was cause of injury being combat casualties or blast injuries versus what is more commonly seen in the civilian patient population and that's amputation from vascular disease or diabetes. There are a lot of distinguishing features between the patients that we were seeing coming back from Iraq and Afghanistan than what you would typically see in a civilian hospital.
So you have a lot of young, healthy people who are suddenly injured compared to people who have progressively gotten worse?
Dr. Pasquina: The majority of the patients that we’re taking care of were of younger age which in itself creates significant challenges. Challenges with body image, self image, forming relationships, figuring out what they’re going to do with their life, but at the same time creates other opportunities. One of the other distinguishing features for the types of folks that we are seeing with limb loss is the high percentage of individuals with upper limb loss. And when we looked out at the technology that was available, let’s say a decade ago, there were very little advances in upper limb prosthetics. There have been huge gains in lower limb prosthetics. People are able to return to running marathons, returning to active duty; para-trooping and doing a variety of different high level activities. But for upper limbs, most of our service members even with the highest technology, were either using a cable driven system that had a hook at the end or a myoelectric system which was mechanical motors. But it really could just do two things; open a hand or close a hand using electrodes that were placed on the surface of the skin of the forearm, the back of the forearm or the front of the forearm to only allow them to do one thing at a time and then they would have to switch and use unnatural motions or muscle contractions to do various motions.
So by implanting it, what have you been able to accomplish then?
Dr. Pasquina: One of the limitations with using surface electrodes is you can only pick up muscle activity of those muscles that are close to the skin. Some of the deeper muscles in the forearm that do control the thumb, the wrist, or some of the finger motions, you couldn’t get at with a surface electrode. In addition to that with the surface electrode, the socket has to be much tighter cause those electrodes have to be on the surface of the skin, so it makes the socket a little bit less comfortable. The other problems are if the socket rotates; those electrodes may not give good contact and then finally if an individual sweats, so many of the folks with upper limb loss will just throw away their prostheses during the summer months or when they are doing high level activities because that surface contact just becomes unreliable, because of the sweat. So we thought if we could put electrodes underneath the skin and put them into the muscles directly, we’d have a lot better control. This is what we did and now our second patient, Ramon, is the second patient in this trial where we implanted 8 of these electrodes into residual muscles of his forearm to get at the exact muscle that does the motion that we want to program the arm to do. Right now for example, we have an electrode in his forearm muscle that is the muscle you use to rotate your wrist in and that’s when he thinks rotate my wrist in, his arm now rotates in. Same thing with rotate out, same thing with flex your thumb in; extend your thumb out; and close and open your hand. The interesting thing with Ramone, different than our first service member, was that Ramon is now 7 years out from his injury, so these are muscles in his forearm that he has not used for 7 years. It’s very interesting to see how he is progressing. We initially put these electrodes in and the first two weeks were just healing, but after two weeks, we could clearly pick up those signals. He was having a lot of difficulty in figuring out, okay, how do I move my thumb again? Just in the past month, he’s improved dramatically. He hasn’t even had the chance to bring this prosthesis home with him now. He just received it last Thursday. He’s only been able to train for an hour when he comes into clinic, but this week he will be able to leave and take this prosthesis home with him and use it for his every day activities. Obviously, we’ll see him back for training and reevaluation, but we anticipate that he’ll do as well as our first subject and be able to incorporate this into many of his activities of daily living.
How is this helping him emotionally?
Dr. Pasquina: There’s a huge emotional component to this. One cannot work at an installation of facility like Walter Reed or the Uniform Services University or the Military Healthcare System in general and not be moved by every one of our service members stories; whether you’re talking about a soldier, a sailor, airman or marine; they all have, inspiring stories so it’s really a privilege for us to take care of them. But at the same time, we owe it to them to come up with the next generation of technology. To be satisfied with what we have now is not what we are here to do. It’s to really identify what those needs are and we’re very fortunate to be in a system where we have the support from the President all the way down in terms of investment and research and technology and clinical services and education to hopefully not just help Ramon and his colleagues, but as he put it for future service members that hopefully will never get injured, but in the event that they do that we’re here to take care of them.
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