Switzerland: Three paralyzed people walk again thanks to spinal cord implants | Science & Technology
Three people paralyzed in motorcycle accidents have been able to walk again thanks to a system developed by Swiss researchers using implants placed directly on the spinal cord.
All three individuals had lost their trunk and leg motor skills due to complete spinal cord injuries. “The day after I started exercising, I saw my legs moving again; It was a very intense emotion,” said Michel Rocatti, one of the three patients, at a press conference.
Neuroscientist Grégoire Courtine from the Swiss Federal Institute of Technology (EPFL) in Lausanne and neurosurgeon Jocelyne Bloch from the University Hospital of Lausanne (CHUV) led the scientific team that achieved this feat.
In a four-hour operation, doctors attached electrodes that emit synchronized electrical signals that mimic the signals that normally travel through the spinal cord to transmit the brain’s instructions to the lower limbs. These implants are connected to a computer with artificial intelligence software that reproduces the necessary impulses for the patient to stand, walk and even perform more complex activities such as riding a special bike and swimming. The achievement was detailed in a paper published on Monday in naturopathy.
This new milestone adds to advances made by two teams in the United States that used continuous electrical stimulation to get paralyzed patients walking again. The main idea emerging from this work is that some forms of spinal cord injury are no longer irreversible.
Courtine’s team has been trying to help paralyzed people walk again for years. In 2014, the researchers tested their system on mice with severed spinal cords, and two years later on monkeys. In the fall of 2018, the Swiss team showed their progress with David Mzee, a young man who was in a wheelchair at the age of 20 after suffering a partial spinal cord injury. Thanks to electrical stimulation of the spinal neurons, Mzee was able to stand and walk a few steps with a walker.
In the last study, the electrodes and their long cables were specially made for the test, taking into account each patient’s injuries. “So far, all of these types of implants have reused electrodes that were originally designed to treat pain,” Courtine explained. “By developing specific technology for this new use for the first time, we can better synchronize the stimulation with the movement itself, for example by mimicking the real signals that the brain sends out when walking.”
On this occasion, the scientists managed to stimulate not only the spinal neurons responsible for leg movement, but also those that regulate the abdominal and lower back muscles. Patients were able to stand up soon after the operation and take their first steps in a harness. It took a lot of training to hone her moves, but after four or five months, Rocatti was able to walk the streets and have a drink standing up at a bar. He now uses a walker, which allows him to control the intensity and pace of the electrical impulses. “When I use the device, I feel better, stronger and the pain associated with the wheelchair goes away,” he said.
The Swiss team treated nine people with the experimental system. Courtine said his team hopes to start clinical trials with more patients in 2023, in part through Onward Medical, a company he founded with Bloch to commercialize the technology going forward. The experiments will take a few more years of work. “We’re going as fast as we can,” said the neuroscientist.
When I use the device I feel better, stronger and the pain associated with the wheelchair goes away
Michel Rocatti, patient
“These new results are spectacular,” said Filipe Barroso, a researcher in the Neurorehabilitation Group at the Cajal Institute, part of Spain’s National Research Council (CSIC). In his opinion, the most notable achievement is the fact that these three patients had complete spinal cord injury, rather than partial as in the 2018 patients, who retained some residual function. “And the results were visible in just one day, which can be explained by optimal placement of the electrodes,” he added.
Barroso is working on less invasive stimulation systems that can be placed on the skin or in the muscles. In the latter case, his team showed last summer that electrodes can achieve a “spectacular” reduction in tremors in patients with diseases of the nervous system.
Diego Serrano, a researcher at the University of Castilla-La Mancha in Spain, visited Courtine and Bloch’s laboratory in 2018. “It’s obvious that they are refining their technique to achieve the most natural movement possible,” he said. “The electrodes are now implanted with pinpoint accuracy, and the fact that they are placed a millimeter or two higher or lower makes a big difference.”
But Serrano also said it will be complicated to use this technology on a larger number of patients. “It’s difficult because every spinal cord injury is very specific, practically unique, which means you have to develop a specific treatment for each person.”