Three people who had been left paraplegic after motorcycle accidents have managed to get back on their feet and take a few steps. It has been thanks to a surgical intervention to implant 16 electrodes directly on his spinal cord. All three participants had lost all ability to move in their lower extremities and trunk due to the complete severing of the spinal cord. “One day after I started practicing I saw that my legs were moving again; It was a very intense emotion”, explained Michel Rocatti, one of the three patients, at a press conference.
The neuroscientist Grégoire Courtine, from the Federal Polytechnic School of Lausanne (Switzerland), and the neurosurgeon Jocelyne Bloch, from the university hospital in the same city, lead the scientific team responsible for this achievement. In a four-hour operation, electrodes have been implanted that emit synchronized electrical pulses that mimic the signals that circulate along the spinal cord, and this links the brain with the lower limbs. And in turn, the electrodes are connected to a computer with an artificial intelligence system that reproduces the impulses necessary to walk, ride a special bicycle or row a canoe, three of the activities that the participants in this study have managed to carry out , whose details are published this Monday in Natural Medicine.
Courtine’s team has spent years trying to restore mobility to people who were paraplegic due to accidents. In 2014, she tested her system on mice that had previously had their marrow removed, and two years later she did the same on monkeys. In autumn 2018, the Swiss team presented the innovations with David Mzee, a young man who became a paraplegic at the age of 20. Thanks to this type of epidural stimulation and with the help of a walker, Mzee was able to walk again.
The new work published this Monday presents a great novelty: for the first time the electrodes and the long cables that are connected to them have been manufactured specifically for this trial and taking into account the particular injuries of each participant. “Until now, all implants of this type reused electrodes originally designed to treat pain,” explains Courtine. “For the first time, designing a specific technology for this new use allows us to better synchronize stimulation with the moment of movement, imitating the real signals sent by the brain when walking, for example,” details the scientist.
On this occasion it has been possible to stimulate not only the nerves that move the legs, but also the muscles of the abdomen and lower back. The participants were able to return to their feet immediately after the operation and took their first steps, initially suspended in a harness. Fine-tuning the movements took time to train, but finally, after about four or five months, Rocatti, for example, was able to walk down the street and go out for a drink at a bar, walking with a walker from which he can control the intensity and rate of electrical impulses. “When I use the device I feel better, I feel stronger and the pain associated with the wheelchair disappears”, explained the patient.
Injuries that are no longer irreversible
The advance is added to those achieved by two US teams that use continuous electrical stimulation systems and that have also allowed some patients to walk after being paraplegic due to accidents. The most important idea behind this work is that some spinal cord injuries should no longer be considered irreversible. In the case of the three patients treated by Courtine, the team was able to verify that perhaps there is some spinal cord that had not been severed by the accident and that it returns to activate and timidly push the muscles of the legs and chest.
The Swiss team has already treated nine people. For now it is only an experimental intervention for a very small number of injured people. But Courtine explains that her team hopes to start the first clinical trials with more patients in 2023, in part through Onward Medical, the company that she has created together with Bloch for the future commercialization of this technology. The trials will still take a few years of work. “We’re going as fast as we can,” says the neuroscientist.
“These new results are spectacular,” says Filipe Barroso, a researcher in the neurorehabilitation group at the Cajal Institute (CSIC), in Madrid. He indicates that the most outstanding thing is that these are patients with a complete spinal cord injury, compared to the previous ones in 2018, who did preserve some residual function. “Furthermore, the results appear in one day, which is explained by the optimal placement of the electrodes”, he highlights.
Barroso works with less invasive stimulation systems that can be placed on the skin or even inside the muscles. In the latter case, his team demonstrated last summer that electrodes achieve a “spectacular” reduction in tremors in patients with nervous system disorders.
Diego Serrano, a researcher at the University of Castilla-La Mancha, visited Courtine and Bloch’s laboratory in 2018. “It is clear that they are fine-tuning their technique to achieve the most natural movement possible,” he highlights. “The electrodes are now implanted with millimeter precision, in fact, placing it one or two millimeters higher or lower has enormous results,” highlights the expert, who sees “complicated” expanding the scope of this technology to a greater number of patients. “It’s difficult because each spinal cord injury is very specific, practically unique, so you need to develop a specific treatment for each one,” he adds.
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George Holan is chief editor at Plainsmen Post and has articles published in many notable publications in the last decade.