THE NOVEL USE OF ACOUSTIC EMISSION MONITORING DURING PROOF-TESTING OF CERAMIC SPINAL IMPLANTS

摘要

An added level of safety and reliability is required of implantable medical devices, particularly when they are prepared from brittle materials. For ceramics, proof-testing has been commonly employed as an inspection method to assure that devices meet minimum acceptance standards. However, proof-testing does not necessarily identify all latent defects. Consequently, subsequent visual inspection methods are employed to eliminate potentially flawed components. In this study, a novel approach of coupling acoustic emission (AE) monitoring with proof-testing was developed for silicon nitride (Si3N4) intervertebral spinal spacers in order to eliminate the need for subjective visual inspection. The characteristic difference in AE signals for defective and non-defective components was rationalized and validated. AE testing was able to identify defects which led to crack propagation during proof-testing. These types of defects would have otherwise remained undetected or required additional inspection using less reliable and more time-consuming techniques.