The patients' injuries to a region called the thoracic spine - below
the neck and above the lowest part of the back - were sustained one
to nine years before receiving the treatment. They were able to take
their first steps within an hour after neurosurgeons first implanted
prototypes of a nerve-stimulation device remotely controlled by
artificial-intelligence software.
Over the next six months, the patients regained the ability to
engage in the more advanced activities - walking, cycling and
swimming in community settings outside of the clinic - by
controlling the nerve-stimulation devices themselves using a
touchscreen tablet, the researchers said.
The patients - men ages 29, 32, and 41 - all were injured in motor
bike accidents.
Grégoire Courtine and Jocelyne Bloch of the Swiss Federal Institute
of Technology in Lausanne led the study published in the journal
Nature Medicine https://www.nature.com/articles/s41591-021-01663-5.
They helped establish a Netherlands-based technology company called
Onward Medical that is working to commercialize the system.
The company expects to launch a trial in about a year involving 70
to 100 patients, primarily in the United States, Courtine said.
There is no existing treatment to enable the spinal cord to heal
itself, but researchers have pursued ways to help paralyzed people
regain mobility through technology.
If this study's early results are confirmed in larger studies,
people immobilized by spinal cord injuries may someday be able to
open a smartphone or talk to a smartwatch, select an activity such
as "walk" or "sit," then send a message to an implanted device that
will stimulate their nerves and muscles to make the appropriate
movements happen, the researchers said.
Normally to initiate movement the brain sends a message to the
spinal cord, telling it to stimulate a pool of nerve cells that in
turn activate the necessary muscles, Bloch said.
"It's something we don't even think about," Bloch said. "It comes
automatically."
After complete spinal cord injury, messages from the brain cannot
reach the nerves. Other researchers have tried to help paralyzed
patients walk by stimulating nerves through the back of the spine,
using broad electrical fields emitted by implanted devices
originally designed to control chronic pain, Courtine said.
Courtine and Bloch and their team redesigned the devices so that
electrical signals would enter the spine from the sides instead of
from the back. This approach allows very specific targeting and
activation of spinal cord regions, Courtine said.
They then devised artificial intelligence algorithms that instruct
electrodes on the device to emit signals to stimulate, in the proper
sequence, the individual nerves that control the trunk and leg
muscles needed for various activities such as getting up from a
chair, sitting down and walking.
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The software is tailored to each patient's
anatomy, Courtine said.
When the device was implanted, patients could
"immediately activate their legs and step," Bloch said.
But because their muscles were weak from disuse, they needed help
with weight-bearing, and they needed to learn how to work with the
technology, the researchers said.
The researchers noted that while the patients regained the ability
to perform various activities, including controlling their truck
muscles, for "extensive periods," they did not regain natural
movements.
Still, Bloch said, "The more they train, the more they start lifting
their muscles, the more fluid it becomes."
MOUSE STUDY
Another peer-reviewed paper by a separate research team in Israel
published on Monday in the journal Advanced Science
https://onlinelibrary.wiley.com/doi/
10.1002/
advs.202105694 describes an experimental approach for repairing
spinal cord injuries. Researchers at Tel Aviv University attempted
to repair the spinal cords in injured mice using adult human cells
that had been engineered to behave like embryonic stem cells, which
can develop into any type of cell in the body.
The animals' spinal cords had formed scar tissue, which has impeded
any benefit of such cells in earlier studies. The researchers first
allowed the stem cells to flourish in a special test tube
environment, only transplanting them into the mice after the cells
had matured into a small network of nerve cells and after the scar
tissue had been surgically removed.
They reported achieving an 80% success rate in restoring movement
and sensation to the paralyzed mice. The researchers said they aim
to launch human trials within a few years.
Efforts to use such stem cells to help the spine repair itself and
restore the function of organs and limbs have yet to produce an
approved treatment in humans.
"There is a long way to prove that it works also in humans, but this
is our goal," said Tal Dvir, who led the team at the Sagol Center
for Regenerative Biotechnology.
(Reporting by Nancy Lapid in New York and Ari Rabinovitch in
Jerusalem; Editing by Will Dunham and Michele Gershberg)
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