Summary: UCLA researchers in the Department of Mechanical and Aerospace Engineering have proposed an electromagnetic attachment strategy for assistive devices that limits direct mechanical contact to soft tissue and minimizes chronic infection risks. Background: Assistive devices, such as prosthetics and exoskeletons, are common clinical outcomes for a variety of medical conditions. Despite recent improvements in assistive device technology, attachment of prostheses and exoskeletons to the body remains challenging. One main function of these assistive devices is to bear external loads, typically through mechanical transfer of force to the body. Traditional attachment methods involve direct contact of the device with a suction liner in the attachment socket. This method typically leads to mechanical load being transferred to highly sensitive soft tissues (i.e. skin, fat) instead of directly to the skeletal system, leading to patient pain and discomfort during prolonged use of the device. Additionally, the liner is non-porous and non-breathable, which increases discomfort and leads to a ‘hotbed’ of ulcers. Newer methods to prevent this discomfort include percutaneous osseointegration (OI) which involves direct skeletal anchoring via a metal implant attached to the bone that protrudes distally through the skin for device attachment. However, OI attachment methods suffer from obligatory chronic perforation of the skin envelope and the consequent infection risk. There remains an unmet need for a device fixation strategy that limits pain, discomfort, and infection risk while maintaining functionality.
Innovation: A team of researchers at UCLA have proposed a novel socket suspension paradigm that enables direct transmission of mechanical load to residual bone, while maintaining a sealed skin envelope. Using principles of electromagnetism, the proposed attachment device will exhibit magnetic attraction to a surgical implant placed in the socket. Bone-anchored, subcutaneous ferromagnetic implants are pulled on by electromagnets outside the body, reducing the mechanical strain on various soft tissues. This obviates the need for the suction function of traditional liners, paving the way for lower-profile sockets and porous liners that pad the skin without creating ulcers. The degree of attraction between the attachment device and the electromagnetic implant can be varied depending on the desired need and use of the device. This new method of attachment confers all the benefits of an OI approach but eliminates the risk for transcutaneous infection, which is seemingly inescapable in the near term.
Patent:
System and method for improved attachment of assistive devices Potential Applications: • Prosthetic attachment • Orthoses • Exoskeleton device attachment
Advantages: • Increased comfort • Smaller-profile devices • Less susceptible to infection • Dramatically increased socket fit • Transferring of force electromagnetically instead of mechanical attachment • Generates attractive forces versus repulsive forces
Reference: UCLA Case No. 2022-115
Lead Inventor: Tyler Clites