Watch
A pioneering surgical procedure provides amputees with bionic limbs that are directly controlled by the nervous system, allowing patients to sense the limb’s position in space.
Scientists demonstrated the success of the technique in a new study of seven people who received bionic legs, published Monday (July 1) in the journal Natural medicine. Including these seven, about 60 people worldwide have undergone this type of procedure, which can be used to install bionic legs or arms.
“This is the first prosthetic study in history to show a prosthetic leg under full neural modulation where biomimetic walking occurs,” Hugh Herrco-author of the study and professor of media arts and sciences at MIT, said va declaration. In other words, a synthetic prosthesis is able to supplement the lost function of the missing limb and thus create a natural gait.
“No one has been able to demonstrate this level of brain control that creates a natural gait where the human nervous system is controlling the movement, not a robotic control algorithm,” Herr said.
Related: ‘You can feel like you’re touching another person’: New prosthetic device detects temperature
The operation itself, the so-called agonist-antagonist of the myoneural interface (AMI), involves the reattachment of muscles in a patient’s residual limb after a below-the-knee amputation in the event that the patient receives a bionic leg.
Electrical signals from central nervous system, which convey movement instructions, can then pass between these muscles and be detected by electrodes in the newly installed prosthetic limb. The signals are picked up by a robotic controller in the prosthesis, which allows it to control the patient’s gait or manner of walking. Signals about the position and movement of the patient’s prosthesis are then fed back to the nervous system.
In a series of experiments described in the new paper, seven patients who underwent AMI surgery were able to walk faster than people who received the same type of prosthetic limb but had traditional amputations. Some of the patients were even able to walk at the same speed as people without amputations. They were also able to avoid obstacles and climb stairs more naturally than patients who underwent traditional amputations.
Current prosthetic limb technology already allows amputees to achieve a natural gait, according to the team that performed the surgery. However, these prosthetic limbs rely on robotic sensors and controllers to actually move according to a predefined algorithmic pattern, the team said. AMI, on the other hand, allows the limb to dynamically respond to signals from the body.
“The approach we’re taking is trying to comprehensively connect the human brain with electromechanics,” Herr said.
Patients who underwent AMI also experienced less pain and muscle atrophy, the researchers reported.
AMI can also be used in people who have an arm amputation, the team said, and the surgery can be performed either during the patient’s original amputation or later.
“This work represents the next step in our demonstration of what is possible in terms of restoration of function in patients who suffer from severe limb injuries,” Dr. Matthew Cartystudy co-author and associate professor of surgery at Harvard Medical School, said in a statement.
Have you ever wondered why? some people build muscle more easily than others or why freckles appear in the sun? Send us your questions about how the human body works community@livescience.com with the subject “Health Desk Q” and you can see the answer to your question on the web!