July 1, 2013
“After surgery to reroute remaining nerves, arm-amputation patients can control a cutting-edge, motorized prosthetic via thought. Marlis Gonzalez-Fernandez says a crucial step in the rehabilitative process, however, is helping each patient adjust to life without a limb.”
Open and close your hand. Tap your index finger to your thumb. Wave your pinkie. Because each little movement is controlled by an intricate system of nerves and muscles transmitting signals from the brain to your fingers and hand, it would be easy to assume that if your hand or arm is amputated, all those fine motor skills would be lost.
But it doesn’t have to be that way.
Even after the hand or a portion of the arm is gone, those nerves and muscles remain, still transmitting signals to the absent hand. In recent years, surgeons have developed a method called targeted muscle reinnervation, or TMR, to reroute those remaining nerves to spare muscle so that amputees can operate a motorized prosthetic with the same motor commands they used before they lost their arm. Although TMR is still not widely available—Johns Hopkins is one of only two places that offers it—the procedure represents welcome progress for patients who hope to one day regain some level of motor function.
Once the surgery is done, however, there’s much more work to do, a good bit of which requires the expertise of the physiatrists and therapists in the Department of Physical Medicine and Rehabilitation.
“What the hands need to do is so much more complicated than what feet need to do,” says physiatrist Marlís González-Fernández. “We look at the patient from a global level and try to manage the complications that may hinder their progress with the procedure. Most of our work relates to pain control and making sure that they have enough support to perform their daily activities.”
All amputee patients have significant adjustments to make, whether they’re a candidate for TMR or a basic, non-motorized prosthetic. “As a rehabilitation physician, I want to make sure my patient has adapted to life with one arm,” González-Fernández says.
For some patients, that may require attention to complex issues, from pain management to transportation. But it also includes very basic challenges, such as learning to button shirts or fix hair. “Everything we do is function-driven,” González-Fernández explains. “We have to evaluate which activities they can do with one hand and who will be able to help them with activities they can’t perform. As patients start learning to use a motorized prosthetic device, I want to make sure that their needs are being met throughout that process from a functional standpoint.”
Although it is still too early to know the extent of fine-motor control that TMR patients may be able to attain with a motorized prosthetic, says González-Fernández, “now we’re able to offer something that could potentially help them live life closer to how they did before the amputation.”