ResMag: A Resorbable Magnesium Alloy for Medical Applications
To repair or reconstruct bone, orthopedic surgeons generally select non-degradable stainless steel or titanium implants. These materials have high strength and stiffness but over time with healing this creates a tensile mismatch with the native bone, which weakens over time as a result. To improve the success rate of orthopedic implants and reduce the use of permanent stainless steel or titanium implants, researchers at the University of Pittsburgh have developed ResMag, a novel resorbable magnesium alloy. Magnesium is a preferred material because it is non-toxic, degrades in a physiological environment, is lightweight, has a density similar to cortical bone, has elastic modulus that is much closer to natural bone, is essential to human metabolism, is a cofactor for many enzymes, and stabilizes the structures of DNA and RNA.
Description
The novel biodegradable, metal alloy is comprised of about 0.5 to about 4.0 weight percent of yttrium, from greater than zero to about 1.0 weight percent of calcium, from about 0.25 weight percent to about 1.0 weight percent of zirconium, and a balance of magnesium, based on the total weight of the composition. The ResMag technology has been successfully tested in cellular assays and in rodent subcutaneous, osteotomy and cranial models implanting the alloy subcutaneously as well as in fractured femurs, and calvaria. In all the rodent studies, ResMag fostered a significantly higher rate of cell viability and did produce gas pockets within a week of implantation that subsided in time. There was no accumulation of magnesium or other metals in the blood or organs, and no measurable adverse effects of the ResMag implant systemically in the blood, serum, liver, spleen, kidney, brain or within and around the implanted tissue.Applications
· Orthopedic surgery· Craniofacial surgery
· Cardiovascular, tracheal, biliary, or lobar stents
· Nerve guides
Advantages
· Matches the natural bone matrix with similar density, elastic modulus and strength· Enables an increase in strength and elasticity of the implant as well as customizes the rate of degradation
· Fosters a significantly higher rate of cell viability
· Not likely to have adverse effects with no accumulation of magnesium or other metals in the blood, tissue, or organs