Thursday, August 02, 2007

Yazoo man gets most out of life with advanced prosthesis

Landing the fish is easy for a self-proclaimed Yazoo City outdoorsman.

Taking his squirmy catch off the hook is the tricky part.
Small things, simple things, just aren't that easy anymore for 25-year-old Anthony McCool.

Try pushing a wheelbarrow with one hand.
Try buttoning a shirt, zipping pants or tying shoes.

Try hammering a nail or using a measuring tape.

McCool, who lost his entire right arm, shoulder and part of his collarbone in an accident at work, has help, though, and is on the cutting edge of technology for amputees. Earlier this year he became the third civilian in the world to be fitted with a $120,000 Otto Bock Myoelectric arm, one of the most innovative prostheses available for upper-extremity losses.

"There are some people out there that will say, 'Well, what do you need it for?' " McCool said.
"They're not me. They don't know. People that don't know are the ones that have two hands."

The device contains carbon fiber, copolymer and silicone, and electric power, not the patient's muscle strength, operates it, said Dr. Rick Psonak, a certified prosthetist in the Department of Orthopedic Surgery's Division of Orthotics and Prosthetics at the University of Mississippi Medical Center. A microprocessor, rechargeable battery and motor supply the power.

McCool must contract his pectoral and rhomboid muscle in his back to turn the device on and switch between three modes: raising and lowering the forearm, rotating the wrist and opening and closing the hand.

The prosthesis is strapped across his torso, and electrodes detect contractions of the two muscles.

"The electrode is like a radio," Psonak said. "It is trying to get a good signal. Then the microprocessor will send power to the battery and motor."

The speed at which the arm moves is proportional to the strength of McCool's muscle contractions.

"Every time he does it, he's working that pectoral muscle. It's almost the same as if you're doing bench presses."

Psonak said improvements to prosthetics and new products spring up about every six months, but the technology is 10 years behind.

"Prosthetics is pretty slow to get the drop down. Electrical engineers make computers. Other engineers work at plastics companies, things like that."

"A lot of this stuff is a spin-off of other things," said Martin Buckner, a certified prosthetist and orthotist in Jackson.

Still, improvements in size, speed and weight of prostheses components in the last 20 years have meant the difference between patients who use them and those who don't.

Batteries are much lighter, smaller and hold their charge longer. They were once as heavy as the arm - 4 or 5 pounds. Microchips are smaller and faster. Motors are smaller and lighter.
Even the design of the prosthesis and the way it fits the patient's body has changed. In the past, a shoulder cap would have been used with McCool's prosthesis, making the weight of the device uncomfortable.

"It would feel like somebody is pushing down on your shoulder the entire time," Psonak said.
Injuries from military service have been the driving force behind the expanded use of the Myoelectric arm, Psonak said. The government has stepped in to help service men and women returning from Iraq acquire the expensive equipment.

"We see the soldiers are fit with this technology, and they put it through the rigors."
In turn, some insurance companies are slowly beginning to offer coverage of prosthetics to policy-holders, Psonak said.

The number of young adults needing prostheses also has pushed the need for advancements, Psonak said.

"Generally, amputations happen from diabetes, which afflicts mainly the older population, folks who are just proud to get from A to B," Psonak said.

"But you get a guy like Anthony. He doesn't want to just get from A to B. He wants to run. He wants to fish. He wants to play with his kids."

Improvements in the works for the Myoelectric arm are fingers and shoulders that move and wrists that turn in different directions. Electrodes are embedded on the muscle inside the arm instead of on the skin's surface, allowing for better control of the device.

Advances in lower-limb prosthetics come at an even faster rate because of higher demand for these devices, Buckner said.

"People don't want to use a wheelchair," Buckner said. "They want to walk. But people will reject upper extremity prosthetics because they can be uncomfortable or too expensive."

The electronic knee is a breakthrough in prosthetics for lower-extremity amputees. The knee measures the patient's activity and can adjust itself for how fast the person is walking and for uneven surfaces and will correct itself if it senses the patient begins to stumble, Buckner said.
Osseointegration is a new technique where metal pins are implanted into the bone at the point of amputation, Buckner said. The prosthesis connects to the pin. Weight is distributed up the prosthesis and into the bone of the leg, which is a more natural distribution of weight. However the risk of infection is extremely high.

The procedure is not offered in the United States, but Buckner said he believes it eventually will be.

Joni McCool said surgeons thought her husband would never be able to wear a prosthesis.
"I guess they weren't aware of the development because he didn't have a shoulder, so they said there's nothing to attach it to," she said.

And if McCool had lost his arm 20 years ago, his best prosthetic alternative would have been a cable and pulley system.

"There's so much movement he has to achieve through gross body movement with that type that it wears and tears on the joint," Psonak said.

The rejection rate of prosthetics was very high 20 years ago, Buckner said. The devices were too uncomfortable or had too little functionality.

"I'd hate for him (McCool) to come to me and say, 'I wear it when I don't do anything, and whenever I do something, that's when I take it off,' " Psonak said.

But McCool has adjusted well to his prosthesis, and now it has helped him return to a near-normal life. He has returned to work, and he hunts, fishes and plays with his two young sons.
"I think Anthony had a new family to live for - two children and a wife," Psonak said. "Being depressed just wasn't an option."

McCool worked at a fertilizer company in Yazoo City. When a machine malfunctioned, he tried to check it out but lost his balance and fell off an observation platform. His hand got caught in the conveyor belt, and he was pulled about 200 feet. He dangled about 3 feet above the floor for an hour before he was freed from the machine by coworkers.

Part of his arm might have been saved, but gangrene set in.

"The big misconception, I think, is folks think, 'Well, this is a permanent arm,' " Psonak said. "This is equipment. It's like having a permanent car or a permanent pair of shoes."

McCool probably will have 20 prostheses in his lifetime.

"Occasionally, you'll have to come in and say something isn't responding that well, so we'll do a service check," Psonak said.

"The part I like is that this is a spiritual thing," Psonak said. "Patients can recover, and I can be there to watch them do it."

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