ur men paralyzed after bad spinal cord injuries can all move their legs again, thanks to an electrical stimulator. Astonished researchers say they’d hoped for some result, but nothing like what they got. They think the stimulator is retraining the mens’ nerves to work with the brain again, despite the terrible damage. “This is wonderful news. Spinal cord injury need no longer be a lifelong sentence of paralysis,” said Dr. Roderic Pettigrew, director of the National Institute of Biomedical Imaging and Bioengineering, one of the National Institutes of Health. “It is just downright marvelous.” Rob Summers, now 28, was the...