The treatment opens a gateway into research on curing paralysis that's never been opened before, and could be subject of FDA trials as early as next year.

"I cannot tell you how excited I am about this work," said Northwestern University's Samuel Stupp, who led the trial. "This is probably the most important paper I've ever written, and it describes a piece of science that was truly unknown."

Spinal cord injuries are generally game over as far as normal movement is concerned—on average, fewer than 3% of the 300,000 people in the U.S. living with such injuries will ever recover meaningful function over their legs.