Polyetheretherketone (PEEK) is a preferred material for vertebral implants due to its biocompatibility, physical properties, and above all its radiolucency. It is a semi-crystalline thermoplastic and therefore prone to absorption of cleaning solvents (0.5wt.% of water by test method ISO 62). This can cause the material to swell and its bulk to become contaminated. Obvious concerns are therefore raised over the choice of cleaning method used for implantable applications (traditionally 99% DI water+1% Alconox).
Since plasma is a dry, gaseous process under low vacuum there are none of the liabilities associated with wet chemistry. After plasma cleaning PEEK the total aerobic bio-burden count (CFU/SIP) was <1 and the quantification of extractable residues by chloroform using gravimetric analysis is compared with standard cleaning methods (see graph below).
