Solvay’s polyarylamide resin stands up to stiff challenges in single-use bone-fixation device 

In developing a more robust, single-use bone-fixation system than currently available devices, medtech startup Reign Medical (Tulsa, OK) went on the hunt for a biocompatible material with exceptional stiffness properties. A polyarylamide (PARA) resin from Solvay (Alpharetta, GA) stood out and is used to mold several components of the medical device soon to be on the market.

Reign Medical's Clench compression staple system

The Clench compression staple system comprises a disposable sterile surgical tool set for fixating hand and foot bone fragments and performing related procedures. A patented threaded hub allows surgeons to incrementally expand the implant for proper insertion while retaining the mechanical properties of the nitinol staples for continuous compression across the fusion site after implantation. Reign Medical specified Solvay’s Ixef GS-1022 PARA, a 50% glass-fiber-reinforced grade, for the device’s implant sizer, drill guide and each part of the implant delivery instrument, including its handle, the saddle on which the staple sits and the threaded compressor that forces the staples fully open, said Solvay in a press release.

A high-stiffness material was required for this application because of the mechanical strain that the components experience. Offering metal-like strength, rigidity and dimensional stability, the biocompatible Ixef PARA polymer also provides an exceptional surface finish, according to Solvay. Available in a range of gamma-stabilized colors, Ixef PARA is optimized for sterilization using high-energy gamma radiation, showing no significant change in appearance or performance after sterilization. The material has been evaluated for ISO 10993 limited-duration biocompatibility and is supported by an FDA Master Access File.

“Our impetus for this kit was to develop a more robust, single-use bone fixation system than is currently available,” said Daniel Lanois, Development Engineer for Reign Medical’s Clench system. “Many competitive solutions use lower performing plastics that do not reliably withstand the force required to hold nitinol staples open, causing the staples to disengage prematurely. After briefly considering polycarbonate and ABS blends, we chose Ixef PARA primarily for its outstanding stiffness, which enabled even the smaller components of the delivery tool to reliably withstand the compression of the staples, as well as the torsional, tamping and axial loads applied during fixation procedures.”

“Solvay’s practice of open innovation promotes the success of customers like Reign Medical by enabling them to focus on their medical device design while we help navigate issues related to materials science and molding challenges,” said Jeff Hrivnak, Business Manager for Healthcare at Solvay’s Specialty Polymers Global Business Unit. “Solvay also conducted a crystallinity study of molded prototypes of Clench system components to validate the tool and ensure that parts were molded properly.”

Reign Medical’s Clench staple system received FDA clearance in April of this year. The company is now conducting beta testing in advance of its first production launch.

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