An Indianapolis medical device company has installed new machining equipment to produce three unique spinal implants made of polyetheretherketone (PEEK). It's a major foray into plastics for implants by Nexxt Spine, which also makes titanium fastening systems.

"This is our first plastic implant, but we make a lot of our instruments, such as handles and sleeves, out of plastic," Andy Elsbury, president of Nexxt Spine, told Plastics Today in an interview. The new equipment is a Haas vertical end mill.

The company recently received 510(k) clearance from the U.S. Food & Drug Administration (FDA) for its new Honour cervical spacer and lumbar spacer implants made of Zeniva PEEK rods.

The implants are offered in different footprints, with applications ranging from the cervical to the lumbar spine.  It is described as versatile enough to accommodate unilateral and bilateral approaches in the lumbar spine with the option to insert directly or initially on its side to prevent potential damage to the ligament and nerve structure.

The spacer systems, made from various sizes of PEEK rods, are hollow so that bone can grow through the device, fusing the adjacent bony surfaces of the vertebrae.

 "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 Eric Lintula, director of engineering for Nexxt Spine. According to Solvay Specialty Polymers USA, Zeniva PEEK also has excellent toughness and fatigue resistance.

Compressive strength

Another advantage of PEEK is repeatability.

"Since the core function of the spacer is to restore the original disc height and maintain this height under physiological loads until arthrodesis occurs, having repeatable compressive strength gives our surgeons confidence they will have consistent clinical results," said Lintula.

Nexxt Spine LLC is a privately held manufacturer of spinal implants and instrumentation founded in 2008. Elsbury has more than 15 years of experience managing design and development of spinal instrumentation and implants, both as a consultant and contractor for companies including JNJ (DePuy) and Medtronic.

Solvay Specialty Polymers USA has made a major investment in its engineering plastics portfolio to become a player in the high-value, and fast-growing medical device market, particularly implantables.

Zeniva PEEK and the line of thermoplastic Solviva Biomaterials are manufactured in compliance with the relevant aspects of ISO 13485 and under the relevant aspects of current Good Manufacturing Practices. Solvay's biomaterial manufacturing processes are validated and special controls provide product traceability. In addition, all materials are tested in an accredited lab that is ISO 17025 compliant.

In an example of how the Solvay program has worked, FDA clearance for the Honour implants was based in part on Solvay's master access file for Zeniva PEEK.

Shawn Shorrock, global healthcare market manager for Solvay Specialty Polymers, said: "The ongoing acceptance of Zeniva PEEK has validated our approach to the spinal market and we're encouraged by the momentum we've generated."