Karin is a 50-year-old Swedish woman who suffered a farming accident more than 20 years ago in which she lost her right hand. A few years later, he took part in a study in which he was implanted with a bionic hand, which he has had for three years. Thanks to the dexterity, reliability and functionality of the prosthesis, coupled with his nervous and skeletal systems, his quality of life has increased and improved. “It is currently the only technology that currently allows a patient to use a prosthesis in daily life that is controlled by implanted electrodes and that allows sensations,” explains Mexican professor Max Ortiz Catalán, author of today Wednesday in the Study published in the journal Science Robotics. Ortiz is also head of neural prosthesis research at the Australian Bionics Institute and founder of the Center for Bionics and Pain Research (CBPR) in Sweden.
Since Karin (the investigation is not revealing her last name) suffered the accident, she has suffered from unbearable pain in her phantom limb: “I felt like I constantly had my hand in a meat grinder, which led to high levels of stress and.” I “I then had to take high doses of various painkillers,” says the press release on the study. In addition, traditional prostheses appeared to be uncomfortable, unreliable and unhelpful in daily life, the study’s press release said. “This research meant a lot to me because it gave me a better life,” he said. Now he explains that he has more control over the prosthesis, experiences less pain and requires “a lot less medication.”
Karin uses the prosthesis at work, when tending to the garden, when cycling and driving. According to Jan Bzinden, author of the study and professor at Chalmers University of Technology, you can also use it for most everyday activities, such as setting the table, preparing dinner or folding laundry. However, the electronic parts of the prosthesis are not waterproof. So if the patient wants to swim, she must first remove the prosthesis and put caps on the threaded implants to protect the connections. It doesn’t make sense for a massage either, explains Ortiz.
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In Spain there are about 60,000 amputees, according to the Spanish Federation of Orthopedic and Orthopedic Technicians (FEDOP). To wear this type of prosthesis, one must meet certain requirements: be over 17 years old and under 70 years old, have enough bone to implant the titanium screw and not suffer from any concomitant diseases or conditions that could interfere with the treatment , explains Bzinden.
The study assessed the quality of life of people with the implant using a questionnaire with questions about mobility, self-care, usual activities, pain or discomfort, and anxiety or depression. Its functionality was also evaluated. The results showed that with the prosthesis, people’s disability and pain decreased and problems with using the implant were reduced.
The patient underwent electromuscular surgery on the stump and received titanium implants in the ulna and radius bone of the forearm. The new bionic technology is characterized by the skeletal fixation of the prosthesis through osseointegration, the process in which “the bone tissue hugs the titanium, creating a strong mechanical connection,” according to the press release. Bzinden explains the process: “Two titanium screws are inserted, one into each bone of the forearm. “The bone grows firmly over these screws, creating a stable and reliable connection point for the prosthesis.”
Using the screws avoids “the unpleasant and often painful experience of carrying a socket,” according to Bzinden. Sockets are the devices used to attach commercially available prostheses to the residual limb. “The surgery reduced the intensity of the phantom limb pain from 5 to 3 and the residual limb pain completely disappeared,” Ortiz explains in the press release.
Karin with a bionic hand that is directly connected to her neuromusculoskeletal system, at the Bionics and Pain Research Center in Gothenburg, Sweden. Ortiz-Catalan et al., Sci. Rob., 2023. (Ortiz-Catalan et al., Sci Rob., 2023.)
The neuromusculoskeletal implant allows the user’s nervous system to be connected to the electronic control system of the prosthesis. “Our integrated surgical and engineering approach also explains the pain reduction because Karin is now using, in a sense, the same neural resources to control the prosthesis that she used for her missing biological hand,” says Ortiz.
According to the study, electrodes were also implanted into the patient’s muscles and around nerves to produce sensations in the missing hand, activated by sensors built into the prosthesis. “When the patient tries to close the hand, this command goes from the brain to the stump, where it is picked up by the electrodes implanted in the nerves and muscles and used to close the robotic hand,” explains Ortiz.
After using the system at home for a year, Karin demonstrated greater myoelectric control capacity, meaning better control of limb movements. He still uses the bionic hand today.
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