Now, researchers at the University of Minnesota have designed a device that could link everything back together again. A silicone guide, covered in 3D-printed neuronal stem cells, can be implanted into the injury site, where it grows new connections between remaining nerves to let patients regain some motor control.

A damaged spinal cord is a difficult injury to patch up, but there are treatments in development. Gene therapy could help break down scar tissue and regenerate nerve cells. In other cases the injury site is bypassed altogether, rerouting messages from the brain through computers or sending the signals wirelessly to a device implanted in the lower part of the body.