Solvay's Zeniva PEEK Biomaterial Finds Application in Envoy's Implantable Hearing System

Envoy Medical Corp., St. Paul, Minn., has developed the industry's first totally implantable hearing system for moderate to severe sensorineural hearing loss. The Esteem® prosthetic hearing restoration device features two terminal connectors made of Zenivapolyetheretherketone (PEEK) resin from Solvay® Specialty Polymers USA, LLC. Zeniva® PEEK - part of Solvay's family of Solviva® Biomaterials - provides biocompatibility, strong insulative properties, and excellent mechanical performance. 

Unlike hearing aids, the Esteem implantable hearing device does not use a microphone or a speaker. Instead, it uses the natural ear drum to detect sound and send a clear message to the brain, via the auditory nerve, by stimulating the cochlea with its prosthetic simulator. Last year, Envoy Medical received pre-market approval (PMA) from the U.S. Food & Drug Administration (FDA) for commercial distribution of the Esteem® implantable hearing device.

"We believe that the Esteem implantable hearing system represents a major breakthrough that provides an alternative to non-implantable and partially implantable hearing aids," said Kevin Verzal, research and development engineer for Envoy Medical. "Zeniva PEEK provides the exceptional properties that are required of a high-precision implant in this critical application."

The innovative design incorporates two terminal connectors (0.1-in by 0.5-in / 2.5 mm by 12.7 mm) for the transducers which are injection molded of Zeniva® PEEK. The biomaterial offers better insulative properties and higher mechanical strength than previously used materials like silicone. Zeniva® PEEK offers many important benefits including biocompatibility and chemical inertness. Based on biocompatibility testing, Zeniva® PEEK demonstrates no evidence of cytotoxicity, sensitization, irritation, or acute systemic toxicity. It also boasts high strength and stiffness and has radiolucent properties which permit x-ray procedures.

Zeniva® PEEK and the entire line of 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 carefully validated and enhanced controls provide product traceability. In addition, all materials are tested in an accredited lab that is ISO 17025 compliant.

Envoy® Medical sells the Esteem implantable hearing device directly to patients. The company matches patients with Envoy-approved surgical centers throughout the U.S. along with its own independently owned surgical center in The Woodlands, Texas.

In addition to Zeniva® PEEK, Solvay's line of Solviva® Biomaterials includes Proniva® self-reinforced polyphenylene (SRP), one of the world's stiffest and strongest unreinforced thermoplastics that offers exceptional biocompatibility and hardness; Veriva® polyphenylsulfone (PPSU), which provides unsurpassed toughness combined with transparency and excellent biocompatibility; and Eviva® polysulfone (PSU), which offers practical toughness in a strong, transparent polymer. These sterilizable products are available in resin for injection molding or extrusion.