Bionic Hand

PART 3

A history of body-restoration attempts, in the form of man-made hands and legs and feet, lines the selves in Robert Lipschutz's office at the Rehabilitation Institute of Chicago (RIC). "The basic technology of prosthetic arms hasn't changed much in the last hundred years, "he says. "Materials are different, so we use plastic instead of leather, butthe basic idea has been the same : hooks and hinges moved by cables or motors, controlled by levels. A lot of amputees coming back from Iraq get devices like these. Here, try this on, "Lipschutz drags a plastic shell off one of this shelves.

It turns out to be a left shoulder and arm. The shoulders part is a kind breastplate, secured scross the chest by a harness. The arm, hinged at the shoulder and elbow, ends in a metal pincer. To extend the arm, you twist your head to the left and press a lever with your chin, and use a little body English to swing the limb out. It is as awkward as it sounds. And hevy. After 20 minutes your neck hurts from the odd posture and the effort of pressing the levers. Many amputees end up putting such arms aside.

"It's hard for me to give people these devices sometimes," Lipschutz says, "because we just don't know if they will really help."What could help more, he and others at RIC think, is the kind prosthesis Amanda Kitts has volunteered to test-one controlled byte brain, not by body parts that normally have nothing to do with moving the hand. A technique called targeted muscle re-innervation uses nerves remaining after an amputation to control an artificial limb. It was first tried in a patient in 2002. Four years later Tommy Kitts, Amanda's husband, read about it on the Internet as his wife lay in a hospital bed after her accident. The truck that had crushed her car had also crushes her arm, from just above the elbow down.

"I was angry, sad, depressed. I just couldn't accept it, "she says. But what Tommy told her about the Chicago arm sounded hopeful. "It seemed like the best option out there, a lot better than motors and switches, "Tommy says. "Amanda actually got excited about it, "Soon they were on a plane to Illinois.

Todd Kiken, a physician and bio-medical engineer at RIC,was the person responsible for what the institute had begun calling the "bionic arm." He knew that nerves in a amputee's stump could still carry signals from the brain. And he knew that a computer in a prosthesis could direct electric motors to move the limb. The problemwas making the connection. Nerves conduct electricity, but they can;t be spliced together with a computer cable. (Nerve fibers and metal wires don't get along well.And an open wound where a wire enters the body would be a dangerous avenue for infections.)


to be continued