Incredible new steps for bionic legs
Professor Hugh Herr is an American rock climber, engineer
and biophysicist. At the age of 17 he was caught in a blizzard while climbing
and ended up losing both his legs below the knee to frostbite. Ever since then,
he’s worked on inventing prosthetic legs that work and feel like real legs. A recent
landmark advance looks like he may well have succeeded.
An article recently published in Nature Medicine showed that Dr Herr had helped seven people with below-the-knee amputations to
be able to walk again. The remarkable feat was achieved using a new type of
surgery and robotic prosthetic legs.
In the groundbreaking step, Dr Herr has been able to help
people walk with bionic legs (mechanical prostheses that mimic real legs) that
are fully controlled by their brains.
In a healthy leg, the main muscles work in pairs, with one
muscle stretching while the other contracts (like the hamstrings and the
quadriceps). Dr Herr’s procedure recreates this structure in people with
amputations.
The surgery involved stitching together the ends of two sets
of leg muscles in the remaining part of the participants’ legs. The new
connections create an “agonist-antagonist
myoneural interface” (AMI). Traditional amputations can’t create these
pairings and the achievement helps patients with the perception of where the
leg is and movement.
Each of the patients was also given a battery-powered
prosthetic leg and control unit that was specially developed by a specialist
team at the Massachusetts Institute of Technology (MIT). The prosthetic legs
were connected to the AMI by electrodes on the skin, so the controllers could
pick up the AMI muscle movements and translate them to movement in the
prosthetic leg.
Once the robotic legs were linked to the AMI, nerve signals
from the brain to the muscles and back allowed the patients to fully control
their new legs.
Although prosthetics controlled by nerve signals have been
made before, they usually only worked during certain movements, like when the
foot is off the ground while walking. But in the study the participants were in
control all the time, which is unique.
The results achieved are impressive. People with the
AMI-linked robotic leg walked 41% faster than people using the same prosthetic,
but with a regular amputation. This meant they could walk as well as people
with natural legs. They could also walk up and down stairs and navigate slopes
and obstacles 32% to 43% faster than those who have had standard amputations.
AMIs can help even without a high-tech bionic leg. Many
people with amputations feel a phantom limb, a ghostly sensation of their lost
leg, which can be deeply uncomfortable. Since 2016, over 50 people have
received AMIs and at least one study reported a reduction in the pain and
discomfort of phantom limbs.
It’s uncertain if the technique could achieve similar
results for amputations involving knees or upper-body limbs. However, more trials
with AMIs and the rapid pace of technological improvement offers real hope for
advancement in prosthetics, potentially restoring function and improving
quality of life for many thousands of people.
About Occupational Health Assessment Ltd – a nationwide occupational health provider
Occupational Health Assessment Ltd provides rapid access to expert occupational health support for businesses across the United
Kingdom. Appointments are available nationwide within two days.
With a unique occupational health assessment service, night worker health assessments, fitness certifications and access to clinics in Belfast, Birmingham, Bradford, Brighton, Bristol, Cardiff, Coventry, Derby, Edinburgh, Glasgow, Hull, Leeds, Leicester, Liverpool, London, Manchester, Newcastle, Northampton, Nottingham, Plymouth, Portsmouth, Reading, Sheffield, Southampton, Stoke, Surrey and more, the business provides high quality, expert medical advice.
Please contact
us for further information or assistance.