Saturday, May 7, 2011

'Smart' prosthetics give amputees more independence

From The Tennessean:

Matt Bulow (pictured left) spent his teenage nights putting ice and salve on the sore spot rubbed raw by an artificial limb, but now he’s at the dawn of a new day in bionic technology.

As the owner of Bulow Biotech Prosthetics, he keeps pace with the latest innovations and helps other amputees get back in motion.

This spring, one of his patients was among the first three U.S. civilians fitted with a “smart” knee that learns the walking strides of its user and adjusts accordingly. Ossur, the Icelandic company that makes the knee, announced Friday that it had developed the world’s first integrated bionic prosthetic leg. Work is under way at Vanderbilt University and other research institutions to develop prosthetics that can send sensory perceptions to the brain by setting up fiber-optic communication between the devices and peripheral nerves.

“Every time we are in a war, we make a lot of gains in prosthetics,” said Dr. Horace Watson, an orthopedic surgeon at Vanderbilt University Medical Center, who has worked with amputees since 1963.

The U.S. Department of Defense has invested millions of dollars into research for prosthetic devices since the start of the wars in Afghanistan and Iraq, but most of the people who will benefit won’t be military. The majority of amputees in the United States, 54 percent, lost a limb because of dysvascular disease — having a defective blood supply, which commonly occurs with diabetics. Traumatic injuries resulted in 45 percent of the cases and cancer in less than 2 percent, according to research by a team from Johns Hopkins University.

Their findings estimated that the nation’s1.6 million amputees will more than double to 3.6 million by the year 2050, with dysvascular disease accounting for most of that increase.

Bulow, who lost part of his leg below the knee because of cancer at the age of 14, also has diabetes. He has not let either condition stop him from being an athlete. He played varsity tennis in high school and competed in the Paralympics, where he held the world record in the long jump for three years. Now 42, he still plays tennis and runs half-marathons.

Most amputees just want to gain independence, Bulow said. “The reality is, everybody doesn’t run. Ninety-eight percent don’t.”

Although soldiers fitted with technologically advanced prosthetic limbs continue serving in the military, most people who get the devices won’t be a “Six Million Dollar Man” or a “Bionic Woman.” Lewis Branson of Clarksville, Tenn., the man Bulow helped get an Ossur Power Knee, is a grandfather who is recovering from heart bypass surgery.

“I love to see that this new technology is helping a 60-year-old Vietnam War vet go do what he wants to do,” Bulow said.

Branson received shrapnel injuries, which resulted in scarring in the arteries of both legs. The war injuries did not cause him to become a double amputee, but they didn’t help the situation when a pallet of ammunition fell on his legs in 1996. Although he underwent 42 surgeries, his legs could not be saved. The Ossur knee prosthetic is for the shorter limb.

Watson said such devices are known as C-legs.

“The C stands for computer,” he said. “It allows the patient to walk and change their gait, change their cadence as they need to, walk faster, walk slower and go up and down steps better than with the old type prostheses.”

One of the best advances over the past couple of decades is myoelectric technologies for upper-extremity amputees, Watson said. The technology allows an electrically powered prosthetic arm, wrist or hand to take direction from muscle contractions at the attachment point.

However, researchers are now aiming for restoring the sense of touch.

“That will be a wonderful milestone when we reach it,” Watson said. “We will see a lot more upper-extremity amputees using their prosthesis. Some refuse to use them because they can’t feel through them. Now if they are a bilateral upper-extremity amputee, they will use their prostheses. They have to.”

Cost can be a barrier. A C-leg costs between $50,000 and $75,000, whereas more traditional prosthetic legs go for $15,000 to $20,000. The myoelectric arms cost around $75,000.

“We like to provide for the patients the most up-to-date, state-of-the-art prosthetics that we possibly can,” Watson said. “Sometimes, we’re limited by what their medical insurance will pay for.”

He said the military personnel he has worked with have not had to worry about that because the federal government is “not sparing any expense” in taking care of them.

Watson, who did his residency at Walter Reed Army Medical Center, said veterans coming home from Vietnam didn’t have the same opportunities for recovery that today’s soldiers do.

Bulow hopes more amputees will learn about innovations and work toward improving their range of motion.

“When I was a kid, you put your leg in a hard socket,” he said. “It was held on literally by a belt. You spent the evenings salving your wounds and icing. Honestly, back then it was like a full-time injury.”