The device, originally developed to help manage pain, comprises 16 electrodes and is placed just below the site of the injury, covering the areas that send sensorimotor signals to the legs. A battery is then implanted inside the abdominal wall, which allows stimulation to be controlled wirelessly. When activated, the device appears to help signals from the brain reach the target muscles, so the person can voluntarily control their own movements again.

Several of the patients that have undergone the treatment are now able to walk, either with support from a frame, or with people on either side holding their hands. Speaking to Business Insider, Claudia Angeli, one of the lead researchers behind the study, said, "It was really amazing. You get to see the little small increments on a daily basis or a weekly basis, and then when it all comes together that is a very emotional time for the participants, and for the team as well in the sense that, okay, we got it, we're able to put the pieces of the puzzle together."

The device doesn't repair the damage, but rather helps brain signals circumvent it. And it's not a quick fix, either. Patients have undergone long and rigorous physical therapy to get to where they are now. Nor will it work for everyone -- two participants in the study didn't relearn how to walk, although they did show significant improvements in standing, holding themselves upright and moving their legs. Nonetheless, the findings are ground-breaking, and herald new hope for those previously told they'll never walk again.

The challenge now, is understanding exactly how the device works. Once the researchers have a better handle on that, they plan to expand the research to other injured participants. "We know the spinal cord can now do this thing, it can regain the ability to walk," Angeli says. "That is huge. We need to be able to reproduce this in a larger number of individuals with different injuries and different time since injuries."