Small step, big deal

Paralyzed can walk with electric implant

Three people whose legs were paralyzed for years can stand and take steps again thanks to an electrical implant that zaps the injured spinal cord, along with months of intense rehab, researchers reported Monday.

The milestone, reported by two teams of scientists working separately, isn’t a cure. The patients walk only with assistance to keep their balance. Switch off the spinal stimulator and they no longer can voluntarily move their legs.

But during one physical-therapy session at the Mayo Clinic, 29-year-old Jered Chinnock moved back and forth enough to cover about the length of a football field.

“The walking side of it isn’t something where I just leave my wheelchair behind and away I go,” said Chinnock, of Tomah, Wis., who was paralyzed in a 2013 snowmobile accident. But, “there is the hopeful side of, maybe I’ll gain that — where I can leave the wheelchair behind, even if it is to walk to the refrigerator.”

The work is part of a quest to help people with spinal-cord injuries regain function. Specialists say while it’s only been attempted in a few people, it’s a promising approach.

Severe spinal-cord injuries leave the brain’s instructions unable to reach nerves that activate muscles. Researchers have tried other technologies, such as encasing patients in robotic-like exoskeletons or implanting muscle stimulators, to help move paralyzed limbs.

With the new approach, the three patients are taking steps under their own power, according to the reports published Monday by Nature Medicine and the New England Journal of Medicine.

How does it work? One theory: Circuits of nerves below the injury site are dormant, but still living. Applying electrical current could wake up some of those circuits and, with rigorous rehab to revive the rusty connections, eventually enable them to receive simple commands.

“Recovery can happen if you have the right circumstances,” said University of Louisville Professor Susan Harkema, who co-authored the New England Journal study. The spinal cord “relearns to do things, not as well as it did before, but it can function.”

Dr. Kendall Lee, a Mayo neurosurgeon who treated Chinnock and co-authored the Nature Medicine report, said the study “gives hope to people who are faced with paralysis that functional control may be possible.”