Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=183487
Story Retrieval Date: 3/11/2014 6:45:22 AM CST
When Dr. David Chen began treating patients, there were no medications or surgical treatments to fix a damaged spinal cord. “Unlike cancer, unlike heart disease, we don’t have a pill or a treatment that’s going to fix it,” Chen said.
Chen is director of the spinal cord injury and rehabilitation program at the Rehabilitation Institute of Chicago. He has been treating patients for 20 years and conducts research on spinal cord injuries.
Being able to help these individuals restore normalcy in their lives, he said, is the most rewarding part of his job - helping people return to productive lives. “Most of it has been providing care to those individuals and seeing them develop along their life course.”
Chen completed medical school at the University of Illinois at Chicago and, during his residency, he became interested in specializing in physical rehabilitation and medicine, focusing on spinal cord injuries and survivors. “In terms of clinical care and research it just seemed that there was a lot that could still be done for those people,” he said.
His focus is on individuals who, either through disease or injury, “have experienced impairment of their ability to function normally,” he said. Impairment of normal functioning can result from strokes, brain and spinal cord injuries, and major injuries resulting from falls, accidents or sports.
Treatments that have been developed – such as functional electrical stimulation – don't heal the spinal cord itself but bypass it, taking signals that are interrupted in the brain and redirecting them directly to muscles.
“My primary focus was treating patients,” he said. The course of treating and seeing different types of injuries and seeing what kinds of treatments existed, however, “sparked an interest in begging to do clinical research in this area.”
Chen began conducting research 15 years ago, investigating the ability of men with spinal cord injuries to have children, as well as medical complications – and their prevention – related to spinal cord injuries.
His current research is focused on enabling people to walk when they have incomplete spinal cord injuries. “When you ask people about their injury, one of the major things they talk about is ‘my ability to stand and walk,’” he said.
When approaching the research, Chen asks himself what he and his colleagues can do to facilitate the movement of those muscles involved in walking and standing. They use therapies, robotic devices, and are studying drugs that might help facilitate return of normal spinal nerve functions in combination with therapies to help people stand and walk.
“It’s been promising seeing people walk more effectively, farther and faster with these treatments,” he said.
Chen's has a prestigious career and has won numerous awards. “Have I been happy in my career? Yes. You do research, you publish papers. You advance in rank. But that’s not why you do it. You’re doing it for science, for the advancement of medical care.”
Functional electrical stimulation is a continually developing therapy that can help restore the mobility of their arms and legs after a spinal cord injury.
Spinal cord injuries are the result of damage to the spinal cord, caused by a wide range of traumas and diseases – such as car accidents, falls, gunshot wounds, spina bifida or multiple sclerosis – leaving a person who suffers the injury with some level of paralysis.
“Functional electrical stimulation is very task-oriented,” said Dr. Deborah Backus, associate director of spinal cord research at the Shepard Center in Atlanta, Ga. It can be used to enable or improve various physical movements, such as walking or grip functioning. The goals of FES are improving muscle mass and tone, as well as providing assistance for mobility and basic organ function.
“If you imagine the brain is like a power generator, the nerves are like the wires and the muscles are like a light bulb,” said Dr. John Lin, medical director of post-acute services at the Shepard Center. “The problem will either be with the generator, the wire, or the bulb.”
FES supplies the electricity that the nerve is not able to provide voluntarily in order to stimulate the muscles – or light the bulb, he said.
Functional electrical stimulation operates by placing electrodes on an area of the body, or implanting them surgically. The electrodes are then connected to lead wires, which run to a generator. The generator supplies electrical pulses – in timed intervals, or manual application – to the electrodes, stimulating the nerves in the area to activate the muscles.
Implanted systems have sensors that detect when a task is being attempted. It then signals the generator to send pulses at the correct time and in the correct sequence to trigger the task.
A commonly implanted form of an FES system is a pacemaker for the heart. The electrical pulse generated is used to stimulate heart function and rhythm. Implanted systems used to treat spinal cord injuries have the system placed close to the area needing stimulation. For example, to restore grip function, the generator is placed near the shoulder, and wires are run to electrodes in the hand.
Functional electrical stimulation is most effective and essential with central nerve injuries, opposed to peripheral nerve injuries, such as a pinched or cut nerve in an extremity of the body. When the spinal cord isn’t damaged, as is the case in peripheral nerve injuries, the brain can take advantage of neuroplasticity – its ability to reroute the nerves connections – and correct the problem.
With peripheral nerve injuries, it depends on how severe the injury is, said Beth Fordyce, a physical therapist at the Center for Rehabilitation Medicine at Emory Hospital in Atlanta, Ga. With a fully severed peripheral nerve, “in essence you cut off the wire,” said Lin. “Unfortunately, once you cut off the electricity, the muscle shrinks down so low that it will not wake back up. Once you pass that window, it’s very difficult to reawaken it,” he said.
“In partial denervation, where the nerve is somewhat hurt, but not severed, then it just depends on the response you get when adding some stimulation back. Maybe you’re just helping the nerve heal better or quicker,” Fordyce said.
But when there is no communication between the brain and peripheral nerves due to spinal cord injuries, “the brain can receive information from the electrical stimulation that allows it to relearn how to use a body part,” Lin said.
FES isn't always a surefire treatment for spinal cord injuries, however. “From a spinal cord perspective, we’ll do a test trial to see how much, if any, voluntary movement we’re getting,” said Dr. Keneshia Kirksey, medical director of the spinal cord unit at the Spain Rehabilitation Center in Birmingham, Ala. “If we’re not seeing any improvement, we’ll lay off of it. You run the risk of burning out the nerves,” she said.
Overworking a nerve – a result of excessive stimulation – can be harmful to the nerve. It is unable to deal with the chemical byproducts of electrical stimulation. “What if a light bulb is only able to handle 60 watts and you put 100 watts into it? You can really bust it up, or do damage to the muscle, that way,” Lin said.
Electrical stimulation has been a recognized medical treatment since the mid-1800s, but FES was pioneered by Vladimir Liberson – an electrophysiologist – who developed multiple devices throughout the 1960s and early 1970s. They included an electro-mechanical device for stimulating the calf and buttock muscles, and a “reflex walking” system, and took advantage of advances in stimulators, allowing them to be used to amplify and switch electric signals.
From these early breakthroughs, researchers in labs worldwide began experimenting with functional electrical stimulation, and have continued to improve the technology.
The spinal cord originates from the base of the brain, extending about 18 inches down the back. Together, the brain and spinal cord comprise the central nervous system. The nerves in the spinal cord are called upper motor neurons, which carry information from lower motor neurons to the brain. Lower motor neurons branch out from every level of the vertebral column, each with a specific area of the body it is responsible for communication with, according to the National Spinal Cord Injury Association.
Spinal cord injuries interrupt the brain’s communication with motor nerves that control muscle function to the limbs or to muscles that control bowel and bladder function. The lack of communication leads to loss of movement and feeling, resulting in either quadriplegia or paraplegia, depending on the type of injury and at what level on the spinal cord it occurs, the association said. Paraplegia is the inability to control bodily functions in the lower extremities, while quadriplegia includes the torso.
The injury is classified into two groups – incomplete and complete. Complete injuries result in no voluntary movement or sensation below the injury site. Incomplete injuries leave some functionality below the level of injury, but still require extensive rehabilitation – including emotional counseling, occupational, and physical therapy – once the injury has been stabilized.
Occupational therapy helps patients cope with everyday tasks, such as bathing, dressing, and using the bathroom. The goal of occupational therapy is promoting patients’ independence, a major rehabilitative component in restoring a sense of normalcy to their lives. Physical therapy may include exercise, massage therapy, hydrotherapy and other treatments for pain reduction.
Healing better and quicker, however it happens, is most important to those who have suffered injury. In the quest to re-establish normalcy and improve quality of life, patients may rely on continued physical therapy – along with the support of family and physicians.
“[Rehabilitation] definitely enables you to do more than you could at first. You’re able to do more for yourself; [it] makes you more independent,” said Kevin Lesure, a patient at Next Steps Chicago Spinal Cord Injury Rehab Center.
“It strengthens me, and it motivates me.”