Specialty Polymers versus Metals in Implantable Devices
Today’s healthcare industry continuously seeks solutions with superior properties, lower production cost and simpler manufacturing processes, which has a significant impact on material selection for implantable device manufacturers. In response to these demands, the introduction of high-performance plastics presents sophisticated alternatives to the metallic components traditionally used in implantable medical devices. Solvay provides OEMs with a wide range of specialty polymer biomaterials that enable enhanced performance and more efficient manufacturing while lowering capital investment. Though titanium remains a common implant material, OEMs are embracing Solvay specialty polymers for their superior properties across a range of applications, including spinal cage implants, posterior and anterior cervical plates, interbody fusion devices, anchors, bone screws and vascular access ports.
Until recently, implantable devices manufactured with metal were preferred in the healthcare industry. However, in an effort to lower costs and increase operational efficiency, OEMs and healthcare professionals have shifted away from metal-based implants. The use of specialty polymers such as PEEK (polyetheretherketone), PSU (polysulfone) and PPSU (polyphenylsulfone) in conjunction with or to completely replace conventional metallic components offers significant improvements to both the performance and production of implantable devices.
For over 30 years, Solvay has led the industry in the development and production of high-performance polymer biomaterials. Today, Solvay specialty polymers such as Zeniva® PEEK, Eviva® PSU and Veriva® PPSU are equipped with advanced properties that facilitate enhanced functional performance and cost-effective manufacturing.
The advanced properties of specialty polymers in implantable medical devices far surpass those of metallic components. For instance, Zeniva® CF30 PEEK is a carbon fiber-reinforced polymer that more accurately simulates natural bone density, whereas some metal can be up to 30 times stiffer than bone. This nearly identical modulus makes Zeniva® CF30 PEEK optimal for use in lumbar and cervical spinal fusion cages and other PEEK implants.
Additionally, the chemically resistant properties of Veriva® PPSU allow implantable devices, such as shunts, valves and wire and lead coatings to remain impervious to powerful chemicals in extremely challenging environments. Metals, however, are easily corroded and compromised by excessive contact with even the most common chemicals. Solvay specialty polymers are also compatible with a full range of gamma sterilization methods, which makes sterility much easier to achieve than metal-based devices.
Unlike metals, specialty polymer medical devices offer enhanced mechanical performance and can be tailored to meet the specific requirements of OEMs. Medical-grade PEEK can be reinforced with carbon fiber, as found in Zeniva® CF30 PEEK, which increases the strength and stiffness of the material. Accordingly, this reinforced biostable plastic is ideal for load-bearing fixations in anterior and posterior interbody fusions.
Additionally, specialty polymers are lighter than metal materials, which reduces stress on surrounding areas and enables a longer device life span. This quality makes Zeniva® PEEK an excellent candidate for long-term PEEK implants such as Suture anchors and bone screws that attach ligaments and tendons to bones. Furthermore, all of Solvay specialty polymers allow for radiolucency in medical imaging, whereas traditional metal components would obstruct the views during X-rays, CT scans, or MRIs.
When comparing polymers versus metals, the efficiency in which they are produced is one of the most significant differences. Solvay’s high-performance polymers are specially formulated for injection molding, which enables OEMs to shape and customize the polymers to fit a variety of molds. Injection-molded, medical-grade PEEK, such as Zeniva® CF30 PEEK, is also optimal for large-scale production and processing, which was previously economically impractical with metallic components.
Unlike traditional metals, Eviva® PSU requires no expensive machining, secondary processing or supplementary coatings. These properties give Solvay specialty polymers a quicker turnaround to market, as these high-performance thermoplastics can be sterilized and colored before machining, which eliminates the need for multi-step, post-treatment finishing and production.