A groundbreaking piece of technology is helping victims of severe spinal trauma regain the use of their legs
This month’s biggest science news, including the world’s first paralysis reversal.
Four patients with severe spinal cord injuries can walk again thanks to a new technique that combines electrically stimulating implants and physical therapy, which has been developed by researchers at the University of Louisville.
Of the four patients in the study, all were able to stand independently and two were able to walk with the assistance of walking aids such as walker frames or horizontal balance poles despite being injured more than two years ago.
“This research demonstrates that some brain-tospine connectivity may be restored years after a spinal cord injury as these participants living with complete motor paralysis were able to walk, stand, regain trunk mobility and recover a number of motor functions without physical assistance when using the epidural stimulator and maintaining focus to take steps,” said Prof Susan Harkema, associate director of the Kentucky Spinal Cord Injury Research Center. “We must expand this research – hopefully, with improved stimulator technology – to more participants to realise the full potential of the progress we’re seeing in the lab, as the potential this provides for the 1.2 million people living with paralysis from a spinal cord injury is tremendous.”
The treatment is based on the idea that, in spite of the damage to the spinal cord, some nerve connections that cross the injury site remain intact. Implants placed below the injury site send pulses of electricity through the area exciting the nerves in the spinal cord. It’s thought that this kickstarts the system: the activity gives the spinal cord, which has been isolated from the brain by the injury, the sensitivity it needs to hear signals from the brain again. This gives the legs a chance to reconnect with the brain and slowly relearn the distinct nerve activation patterns that result in walking via the locomotor training. In a session, the participants are placed into a harness while specially trained staff move their legs to simulate walking on a treadmill.
That’s the theory, in practice however, the precise healing process isn’t fully understood. “Now I think the real challenge starts, and that’s understanding how this happened, why it happened and which patients will respond,” says Kristin Zhao co-principal investigator the study.
Initially, they were unable to stand, walk or voluntarily move their legs, even after eight to nine
“THE TREATMENT IS BASED ON THE IDEA THAT, IN SPITE OF THE DAMAGE TO THE SPINAL CORD, SOME NERVE CONNECTIONS THAT CROSS THE INJURY SITE REMAIN INTACT. IMPLANTS PLACED BELOW THE INJURY SITE SEND PULSES OF ELECTRICITY THROUGH THE AREA EXCITING THE NERVES IN THE SPINAL CORD”
weeks of daily locomotor training. However, once the stimulators were implanted and switched on, all of the participants were able to stand and two of them were able to walk using mobility aids.
“We are seeing increasing interest in the use of technologies such as epidural stimulation in the treatment of spinal cord injury and restoration of locomotor, cardiovascular and urodynamic functions [bladder control],” said Maxwell Boakye, clinical director of the Kentucky Spinal Cord Injury Research Center. “Epidural stimulation is likely to become a standard treatment with several improvements in design of the device to target more specific neurological circuits.”
ABOVE: (From left) Dr Claudia Angeli, Jeff Marquis and Prof Susan Harkema at the Kentucky Spinal Cord Injury Research Center
ABOVE: An X-ray of the epidural implant that provides electrical stimulation to patients with spinal cord injuries