Recently, interbody fusion cage devices have been developed and used for lumbar reconstruction. Stand-alone cages reduce segmental mobility. In this study, we evaluated mechanical properties and biocompatibility of lumbar stand-alone cages. Evaluation of mechanical properties followed the ASTM F2077 standard that covers methods for static and fatigue testing. The sterility test was ensured by the ISO 11737-2. The extractable substances test was ensured by the Korea pharmacopoeia. Cytotoxicity of the specimen was assessed using MTT assay as recommended by the international standard guidelines, ISO 10993-Part 5 for in vitro testing.

Most of passive implants belong to medical device are consist of metallic and nonmetallic materials. According to the sort of components, it makes more influence into the human body. In this study, we performed induced-RF (Induced-Radio Frequency) heating evaluation which is part of MRI (Magnetic Resonance Imaging) compatibility and safety test and in-vivo pyrogen test with lumbar stand-alone cage. RF from 3T MRI coil was radiated on medical device, and provided heat nearby stand-alone cage. Thermal change detected areas are distinguished by metallic and nonmetallic part. As followed detection areas, febrility was shown and metallic part was slightly higher than control area, nonmetallic part. Furthermore, stand-alone cage was performed in accordance with in-vivo pyrogen test, and solution injected rabbits had no fever for test period. Through physically and biologically evaluated stand-alone cage, exothemic reaction was observed and we predicted the effect when it would be inserted in patient.