The treatment of the men began with surgery. Doctors implanted a small patch of electrodes on the surface of the spinal cord in the lower back, below where each injury had occurred. The patch was connected to a pacemaker device, which was placed in the abdomen.
The implanted device, when turned on, delivered bursts of stimulation to individual muscles as they were called into use. The intention to lift a knee generated a certain pattern of nerve firing; stepping forward generated a different one. In effect, the device provided the pattern of stimulation that the body delivered before the injury occurred. Over time — with intensive physical therapy, on a treadmill with hand supports — the stimulation appeared to engage the brain’s motor cortex through nerves that were spared from injury, Dr. Courtine said.
“In the animal studies, the reorganization in the brain was really massive,” Dr. Courtine said. “There were a lot of new connections from the motor cortex to brain stem.” The same would be expected in humans, he said.
After his injury, Mr. Mzee began playing wheelchair rugby, and soon made the national team. The injury also plunged him into research of his own; through a doctor, he learned of the program in Lausanne, and the animal experiments. When he heard that a human trial was in the works, he quickly enlisted.
“It’s really hard to say what’s coming next for me,” Mr. Mzee said. “I think the next step will have to be a huge one, and one of the problems is that I have to have some trunk control. My trunk is not well-balanced. I’m trying to set up a body support system at home to do more rehab but, you know, it’s expensive. I’m still not steady without those supports.”
Even so, rehab — the hard work, sweat and discipline that have proved so helpful for many patients — will be essential to the recovery process. “We’ve known for years that people” with partial paralysis can respond to rehabilitation, Dr. Anderson said. “The problem comes down to access; long-term rehabilitation in the chronic setting is not paid for by very many insurers. As a result, most people with motor incomplete injuries do not recover to their fullest potential.”