US Marine receives first prosthetic arm controlled by implantable sensors

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Published January 20, 2014

| FoxNews.com

After U.S. Marine Staff Sgt. James Sides lost his hand while serving in Afghanistan, he was desperate to get back to his old way of life. Despite the fact that he had mastered the use of his prosthetic, Sides was frustrated by his inability to fluidly do simple things like pick up a water bottle or get money from the ATM.  

“I always felt I was holding up the line,” Sides told FoxNews.com. “I’d have to move my thumb, grab groceries, move the thumb back, then close my hand.”

Sides incurred his injury on July 15, 2012. He was on his second tour of duty in Afghanistan when a booby-trapped improvised explosive device (IED) detonated underneath him. As a result of the explosion, Sides lost both his right hand and the vision in his left eye.

Before his injury, Sides lived an active lifestyle and enjoyed mountain biking, surfing, playing football and rock climbing. Eager to do these things again, Sides decided to go through with an additional amputation upon arriving at Walter Reed National Medical Military Center in Bethesda, Md. – opting to remove half of his forearm so that he would be able to use a prosthetic.

“When they said…they could take the forearm and I would have unlimited prosthetic capabilities…I didn’t even think about it and told the doctors, ‘Yes,'" Sides said.

While undergoing rehabilitation, Sides’ positive attitude attracted the attention of a group of physicians working on a novel device called the implantable myoelectric sensor (IMES) system.  To help amputees gain better control over a prosthetic, the IMES system utilizes electrodes implanted within a patient’s remaining muscles. If successful, doctors hoped the device would allow Sides to intuitively move his thumb, open and close his fist and rotate his wrist – making some of the everyday tasks Sides struggled with, like picking up a water bottle, much easier.

According to Dr. Paul F. Pasquina, principle investigator behind the IMES system and chair of the department of physical medicine and rehabilitation at the Uniformed Services University, current prosthetics often pose difficulties to users.

“Unfortunately during the last now 12 to 13 years, we’ve seen a lot of young service members that have sustained upper limb loss from combat,” Pasquina told FoxNews.com. “And it was very apparent the limitations in the technology that existed during the beginning of the war.”

Upper-limb amputees can choose between body-powered prosthetics or motorized prosthetics - both of which offer only limited movement in the hand. Body-powered prosthetics require the user to pull a cable which prompts the prosthetic’s hand to open and close.

With motorized prosthetics, sensors are placed on the surface of the remaining limb and pick up muscle activity in order to control movement. While motorized arms offer a greater range of motion, they can be very difficult to control and are known to malfunction due to sweating.

“I had two sensors touching the surface of my skin receiving muscle contractions and making it work,” Sides said. “Obviously in summertime you start sweating in the arm that’s covered with the prosthetic and it would go haywire. The hand would open and close by itself. I would quit wearing it in the summer because it was just too humid, it would malfunction, and I would turn it off and take it off.”

With the IMES system, Pasquina and his colleagues have developed a prosthetic controlled by sensors implanted inside the muscles of the recipient’s remaining limb. Whereas motorized arms can only utilize muscles near the surface of the skin, implantable sensors tap into a wider variety of muscles and thereby improve both the prosthetic’s control and range of movement.

“We’re very excited about these implantable electrodes that we can now get better signals from,” Pasquina, who worked with The Alfred Mann Foundation on the trial study, said. “They’re more reliable, they have stronger signals generated from the muscle within, we can get more muscles, deeper muscles and they are more intuitive.”

Sides jumped at the opportunity to become the first person to receive the IMES system.

“We approached him with, ‘Hey there’s this new technology,’ and I don’t think I finished sentence before he said, ‘Hey let’s do it,’” Pasquina said.

After much preparation, and extensive testing to identify where to implant the sensors, Sides underwent surgery and had eight electrodes implanted in the remaining muscles in his right arm. Two weeks later, he was able to start using his new prosthetic.

“It really didn’t hit me until I had the prosthetic to take home and just wearing it day-to-day realizing what I could do with it that I couldn’t do with my old one,” Sides said. “I can’t do anything new, but it’s the fluidness and the quality…grabbing my wallet to get money for the ATM, grabbing and getting groceries, cooking, everything. It’s truly amazing.”

Sides has been working with his new limb for approximately six months, and Pasquina said he and his team are excited by the success of the procedure.

“We’re obviously extremely encouraged with the technology, and we believe it can help many folks in addition to James, not just service members but the general public as well,” Pasquina said. “We have FDA approval to do this initial trail with three patients – James being the first – and we wanted to really make sure this worked before we recruited our second and third patient. Now that he’s six months out, we feel confident moving forward.”

Sides will retire from the Marine Corps on March 30 and return home – along with his new prosthetic – to California.  He has been accepted into a community college there and is hoping to work towards a degree in geology.

URL

http://www.foxnews.com/health/2014/01/20/us-marine-receives-first-prosthetic-arm-controlled-by-implantable-sensors/