A team made up of neurobiologists, therapists, neurosurgeons and engineers has been working for years to achieve something unique: that some spinal cord accidents are no longer considered irreversible.
Thanks to an implant that produces electrical stimuli, they have managed to restore the ability to walk for several people with paralysis from the waist down. Behind this achievement are the French scientist Grégoire Courtine and the startup GTX Medical. Although the story begins a long time ago, and has gone through trial and error and mice.
“You have to be more pragmatic. When you leave the lab tomorrow, I want you to go to the rehab center and see the injured people fighting to make a move, fighting to keep their trunk up. And when you go home, think about what you’re going to change in your research the next day to improve your life,” Grégoire Courtine said at a TED Talk in 2013.
It wasn’t his idea. He was remembering the words of Christopher Reeve (the actor who brought Clark Kent to life in ‘Superman‘ and other superhero movies) at the Christopher and Dana Reeve Foundation. An organization that promotes research to improve the health and quality of life of people with paralysis.
The same actor and founder, known as “The Man of Steel” was in a wheelchair and needed breathing assistance since 1995, when he suffered a serious injury when he fell from a horse. He was already a well-known activist in the fight for the rights of people with paralysis before the accident, and did not give up his motivation until he died in 2004.
For Grégoire Courtine, his words were decisive. Together with the rest of his team, he is researching how to repair spinal cord damage and other neuromotor problems through neuro-rehabilitation and technology. The results of his research have been published in the journal ‘Science’, under the title ‘Targeted neurotechnology restores walking in humans with spinal cord injury‘.
Implants that activate the spinal motor
The work of the GTX Medical startup is based on the idea of stimulating the spinal cord so that it is again possible to voluntarily control the leg muscles. This is not possible after a spinal cord accident, because when the spinal cord is damaged, the signal from the brain is interrupted.
“Imagine that the locomotive system is a car. The engine is the spinal cord. The transmission is interrupted. The engine is off. How could we re-engage the engine? First, we have to provide the fuel; second, press the accelerator; and third, steer the car,” explains Grégoire Courtine in the TED Talk. “It turns out that neural networks from the brain are known to play this role during locomotion. My idea: to replace this lack of input to give the spinal cord the kind of intervention that the brain would naturally provide for walking.
To do this they developed an electrochemical neuroprosthesis that sends electrical signals to the muscles. These activate the same areas of the spinal cord that are activated when the brain determines that the legs should walk.
The prostheses were first tested on rats, which managed to move their legs in a coordinated manner without the signal being derived from the brain. Then, in people, and with success. So far, after several sessions combined with rehabilitation, the prosthesis has succeeded in enabling several people to stand up and walk short distances with walkers or crutches.
The evolution of this technology may represent a significant advance for victims of spinal cord injuries. Which, according to the World Health Organization (WHO), is growing by between 250,000 and 500,000 each year.
The dangers of spinal cord injury
As indicated by WHO, the term “spinal cord injury” refers to damage to the spinal cord as a result of trauma (e.g. car accident or violence) or disease or degeneration (e.g. cancer), although the latter accounts for only about 10% of cases.
The most visible side of these injuries is the partial or complete loss of sensation or motor control in the arms, legs or whole body. However, the consequences go far beyond this. The most serious injuries affect the regulatory systems of the bowel, bladder, breathing, heart rate and blood pressure, as indicated by the world body.
In addition, people with spinal cord injuries are two to five times more likely to die prematurely. In most countries of the world, this problem also manifests itself in lower rates of schooling and great difficulty in entering the world of work. Technology such as GTX Medical can play a very important role in improving the survival, health and participation of people who, through accident or illness, deal with these injuries every day.