Small steps, giant leap for treating spinal cord injuries
A 25-year-old Los Angeles man paralyzed from the waist down after being hit by a car in 2006 has regained the ability to stand, take steps on a treadmill and move his hips, knees, ankles and toes voluntarily as a result of an experimental treatment developed at UCLA and the University of Louisville.
Rob Summers has also regained some bladder and sexual function after intensive rehabilitation and two years of electrical stimulation to his damaged spinal cord with a device normally used for pain relief, researchers reported Thursday.
His recovery “remains unprecedented in spinal cord injury patients,” who until now have faced a lifetime of paralysis, researchers from the University of Zurich wrote in an editorial accompanying the report in the journal Lancet. “We are entering a new era when the time has come for spinal-cord-injured patients to move.”
The new treatment is “a very exciting discovery” that can probably be used to help 10% to 15% of people with spinal cord injuries regain some use of their legs, added Dr. John McDonald, director of the International Center for Spinal Cord Injury at the Kennedy Krieger Institute in Baltimore, who was not involved in the research. For those people, “it has the potential to make a dramatic difference in their lives.”
To achieve this milestone, researchers bathed Summers’ spinal cord with a mild dose of electricity using a device that is used to treat chronic pain. The electrical stimulation apparently primed his nervous system to respond to signals from his limbs, allowing him rise out of his wheelchair.
“To everyone’s disbelief, I was able to stand independently the third day we turned it on,” said Summers, who was a baseball player in his junior year at Oregon State University in Corvallis at the time of his accident. He completely supported himself, but needed some help with balance.
The treatment, devised primarily by UCLA neurobiologist V. Reggie Edgerton, is designed to activate a patient’s spinal nerves just enough to make them responsive to sensory signals coming from the legs. The approach, which Edgerton has been using in animals for nearly three decades, is like using a hearing aid to amplify sound.
The technique “opens up a whole new set of possibilities ... for people who have been injured,” said Dr. Susan Harkema of the University of Louisville, the study’s coauthor.
According to the Christopher and Dana Reeve Foundation, almost 6 million people live with some form of paralysis, about 1.3 million of them from a spinal cord injury. Such people lose not only limb function, but also bladder and bowel control, sexual response and other autonomic functions, sometimes including the ability to breathe on their own.
Researchers have previously used electrical pulses to activate nerves in the legs of spinal cord patients in a specific pattern that caused them stand or move in a walking motion. But in those cases, it is not the patient’s brain but the computer that sends the pulses that has control of the activity.
Summers was paralyzed below the waist after being struck by a car in a hit-and-run accident in July 2006, although he did retain some feeling in his limbs. He spent three years in rehabilitation and physical therapy trying to learn how to stand and walk again, without success.
Then Dr. Jonathan Hodes of the Frazier Rehab Institute at the University of Louisville implanted the 51/2-inch-long epidural stimulation device next to his spine. The device is not optimal for this purpose, Edgerton said, but using it allowed the team to proceed without having to get a new device approved by the Food and Drug Administration. (A team led by Caltech bioengineer Joel W. Burdick is designing newer and better electrode systems.)
The 16-electrode device was placed in his lower back between the vertebrae and the dura, which covers the spine and keeps fluid in. A lead was buried under his skin and tunneled to a pouch above his hip.
The important thing, Edgerton noted, is that the device did not cause Summers to stand, as previous attempts at electrical stimulation have done. When Summers is sitting normally with the stimulus operating, nothing happens. But when he leans forward and puts some weight on the legs, muscle memory takes over and the spine sends signals to the legs that cause him to stand.
With more training, Summers also learned how to walk on a treadmill. Eventually, he developed the ability to move his legs, wiggle his toes, flex his ankles and make other movements voluntarily -- as long as his spinal cord is being stimulated.
At first, “none of us believed it,” Edgerton said. “We have no idea what the mechanisms are, but we are pretty sure it has resulted in changes in the brain.”
And as Summers relearned these rudimentary activities, his autonomic functions also improved. He regained control of his bladder and bowels, as well as some sexual function.
“Not being able to walk and stand is devastating,” Harkema said, “but these other things may be more important.”
Summers’ overall health also began to improve, at least in part because of the exercise. He was able to discontinue a variety of medications for cardiovascular disease and pain. “That was important because they were very expensive,” said Summers, who now attends the University of Louisville and helps coach the baseball team there.
The researchers emphasized that the electrical stimulation alone was not enough to get Summers back on his feet. Rather, it was a combination of the stimulation and the intensive rehabilitation, up to two hours a day.
Dr. Amie B. Jackson of the Spain Rehabilitation Center at the University of Alabama at Birmingham, who was not involved in the research, speculated that this treatment could be combined with other therapies to provide even better, longer-lasting results. Once a patient has reached this stage, she said, it might then be possible to use stem cells to repair the spinal cord and make the improvements more permanent.
Everyone involved cautioned that the experiment involved only one patient and would need to be replicated in others before becoming a mainstream therapy. Harkema said the team will immediately begin testing it on four other patients with injuries similar to Summers’, then will try it on others with different types of injuries.
As for Summers, he said his goals were “to stand completely independently, take steps in a more functional manner, and eventually try to play baseball again.”
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