PARA & PAEK can replace metal in surgical retractors

• PARA for single-use applications: strength & rigidity supasses PEEK
• PAEK for reusable devices: high stiffness-to-weight ratio

Specifying plastics for medical devices is not an easy task for those who have been used to work and design with metals. To help customers make this transition, Solvay Specialty Polymers has released a case study which features the use of its polymers in the healthcare field. The case study focuses on both single-use and reusable retractor applications that use polyarylamide (PARA) and polyaryletherketone (PAEK) resins to replace traditional metal instruments.

The Hohmann retractor, a popular device used in surgical procedures, was selected for the metal replacement case study because of the challenging requirements including high mechanical loads. The study shows that high-performance polymers such as PARA and PAEK offer the same level of strength and rigidity as some metals at ambient temperature along with added advantages. These polymers deliver enhanced aesthetics, and ergonomic improvements including a range of grip options. They can also be colored, thus enabling the production of devices in a variety of sizes that can be easily and quickly identified in the operating room.

In single-use applications, Ixef PARA was used due to its strength and stiffness, good surface finish, and compatibility with gamma radiation sterilization. The material’s strength and rigidity surpasses that of known competitive thermoplastics, including carbon fiber-reinforced polyetheretherketone (PEEK). This enables instrument designs which offer comparable performance to that of their stainless steel counterparts. The material is injection moulded, thus eliminating machining and reducing cost over stainless steel.
For reusable devices, AvaSpire PAEK was used due to its high stiffness-to-weight ratio, hydrolytic stability at elevated temperatures, excellent chemical resistance, as well as very good aesthetics and colorability.
Stiffness, strength, and compatibility with disinfectants and steam sterilization are critical requirements for reusable retractors. The material is also easy to process, allowing designs incorporating long, thin geometries to be produced via injection moulding.

Solvay is presenting these types of case studies directly to customers and also offering them at educational meetings including the recent American Academy of Orthopedic Surgeons (AAOS) conference in New Orleans and the MD&M East conference and exhibition in New York City. The company made the announcement at the 2014 Medical Design & Manufacturing (MD&M) East exhibition June 10-12 in New York City.