EEK replaces titanium in cervical implants
SpineNet (Winter Park, FL) has received 510(k) clearance from the U.S. Food & Drug Administration (FDA) for its new SpineNet ACC anterior cervical cage made of Zeniva polyetheretherketone (PEEK) rods from Solvay Specialty Polymers USA (Alpharetta, GA).
The SpineNet ACC cervical cage is designed to reproduce a tri-cortical iliac crest bone, providing structural support as an interbody spacer for anterior cervical fusions. The superior and inferior surfaces allow for close contact with the endplate surfaces for optimum stability and to resist subsidence. The cages are offered in 10×12 mm and 12×14 mm footprints (5-10 mm height) with several sizing options. They are machined from various sizes of PEEK rods and have windows to allow bone growth, fusing the adjacent bony surfaces of the vertebrae. Radiopaque tantalum rod markers allow for improved positioning.
The design includes teeth on the superior and inferior surfaces Solviva Biomaterials says that Zeniva PEEK has a modulus very close to that of bone as well as excellent toughness and fatigue resistance. “We chose Zeniva PEEK for its similarity to the modulus of elasticity of bone, radiographic properties, and the widespread commercial and regulatory acceptance of the material,” said Rick Kitain, vice president of SpineNet.
Metals such as titanium are often chosen for intervertebral implantable devices. Solvay said that PEEK offers many important benefits including biocompatibility, chemical inertness, and a modulus of elasticity that is close to that of bone. Based on biocompatibility testing, Solvay said that Zeniva PEEK demonstrates no evidence of cytotoxicity, sensitization, irritation, or acute systemic toxicity. “The ongoing acceptance of Zeniva PEEK has validated our approach to the spinal market and we’re encouraged by the momentum we’ve generated,” said Shawn Shorrock, global healthcare market manager for Solvay Specialty Polymers.
Kitain says SpineNet plans to use PEEK in future designs of lumbar interbody devices. SpineNet also uses PEEK in a posterior lumbar interbody fusion (PLIF) cage because it has has better modulus of elasticity to the cancellous (spongy) bone than any other materials, such as metal or carbon fiber. SpineNet was founded in 2007.