Compliant mechanism approach to artificial disc replacement developed
MedWire News: Researchers have developed an artificial disc replacement that could be used to treat chronic low back pain.
Anton Bowden (Brigham Young University, Utah, USA) and team used compliant-mechanism design techniques to design a total disc replacement that is capable of replicating the moment-rotation response and the location of the helical axis of motion, which have been overlooked by the current generation of total disc replacement devices.
Using bench-top testing, the researchers found that the moment-rotation response of the disc replacement matched the intended design behavior. When tested in cadaveric spines, the moment-rotation and displacement response of the implanted segment mimicked those of the healthy spinal segment.
"Low back pain has been described as the most severe pain you can experience that won't kill you," commented Bowden in a press statement. "This device has the potential to alleviate that pain and restore the natural motion of the spine - something current procedures can't replicate."
The current generation of sliding-bearing surface disc replacements do not provide the same segmental quality of motion and energy storage that natural intervertebral discs provide. They rely on the soft tissue surrounding a joint, which may lead to accelerated degeneration.
However, the disc replacement developed by Bowden and team uses compliant mechanisms and receives motion through the deflection of one or more parts, allowing it to facilitate natural spine movement and restore the function of a healthy spinal disc.
"To mimic the response of the spine is very difficult because of the constrained space and the sophistication of the spine and its parts," added co-author Larry Howell, also from Brigham Young University. "A compliant mechanism is more human like, more natural, and the one we've created behaves like a healthy disc."
David Hawkes, President of Crocker Spinal Technologies remarked: "Fusion, which is the current standard of care for back pain, leaves a lot to be desired.
"Disc replacement is an emerging alternative to fusion that has the potential to make a significant difference in the lives of millions."
By Piriya Mahendra