A bionic hand has seamlessly been integrated with nervous and skeletal systems to maintain functionality even after years of daily use.
The mechanical attachment and reliable control of prosthetic limbs represent two of the most significant challenges in artificial limb replacement.
Many individuals with limb loss have historically rejected even advanced commercially available prostheses due to the discomfort and difficulty of attachment and their limited and unpredictable controllability.
However, a multidisciplinary team of engineers and surgeons has overcome these challenges by developing a human-machine interface that allows the prosthesis to be comfortably attached to the user’s skeleton through osseointegration.
Additionally, this interface facilitates an electrical connection with the nervous system through electrodes implanted in the nerves and muscles.
The research was led by Professor Max Ortiz Catalan, who heads the neural prosthetics research at the Bionics Institute in Australia and founded the Centre for Bionics and Pain Research (CBPR) in Sweden.
The success of the integration is exemplified by the case of Karin, a Swedish woman who lost her right hand in a farming accident over two decades ago.
She became the first person with a below-elbow amputation to receive the highly integrated bionic hand, which she has used comfortably and effectively in her daily activities for years.
Karin’s life underwent a profound transformation following the accident. For years, she endured agonising phantom limb pain, leading to substantial stress and reliance on high doses of painkillers.
Conventional prosthetic solutions were uncomfortable and unreliable, offering little assistance in her daily life.
But the prosthesis has relieved her pain with a heightened integration between the bionic hand and Karin’s residual limb.
She said: ‘This research has been life-changing, granting me a vastly improved quality of life.’
Overcoming the challenges in aligning and equally loading the radius and ulna bones and working within limited space for implanted and prosthetic components was a significant feat.
Nevertheless, the research team successfully developed a neuromusculoskeletal implant that connects the user’s biological control system to the prosthesis’s electronic control system, contributing to a reduction in pain.
A central feature is the skeletal attachment of the prosthesis via osseointegration, creating a robust mechanical connection.
Professor Rickard Brånemark, a research affiliate at MIT, an associate professor at Gothenburg University, and CEO of Integrum, spearheaded the surgery and has been involved in osseointegration for limb prostheses since their first use in humans.
He explains that the biological integration of titanium implants into bone tissue presents opportunities to advance amputee care significantly.
Combining osseointegration with reconstructive surgery, implanted electrodes, and artificial intelligence makes it possible to restore human function in an unprecedented manner.
Achieving a high level of functionality at the below-elbow amputation level marks a crucial milestone in advanced extremity reconstruction.
The nerves and muscles in Karin’s residual limb were strategically reconfigured to provide an enhanced source of motor control information for the prosthesis.
Dr Paolo Sassu conducted this aspect of the surgery, which took place at the Sahlgrenska University Hospital in Sweden, and he had previously led the first-hand transplantation performed in Scandinavia.
He emphasised the importance of offering the best solution for patients, which can sometimes be biological with hand transplantation and, in other cases, bionic with a neuromusculoskeletal prosthesis.
The robotic hand, known as Mia Hand and developed by Prensilia, boasts unique motor and sensory components that empower the user to carry out 80% of daily activities.
Dr Francesco Clemente, Managing Director of Prensilia, emphasises the importance of user acceptance in terms of technical performance and aesthetics.
You can watch a video explanation of the technology here.
Photo caption - Karin with her integrated bionic hand and Prof. Max Ortiz Catalan
Credit: Ortiz-Catalan et al., Sci. Rob., 2023
