Toxicity of Metals Released from Implanted Medical Devices

Implanted metallic medical devices release many of the same metals (e.g., aluminum, nickel, cobalt, chromium) that individuals are exposed to from environmental or occupational sources. At sufficiently high doses, these metals can produce adverse effects either at the site of implantation, at target tissues distant to the implant site, or both. As a result, it is necessary to assess the potential local and systemic toxicity of metal ions and metallic wear debris that may be released from implanted medical devices. Adverse health effects associated with metal release from implanted neurological, cardiovascular, and orthopedic devices are explored in this chapter. In this chapter, we also examine the unique issues that should be addressed when estimating the risk posed by exposure of patients to metals released from implanted metallic device, notably, the need to account for the form (particulate vs. ionic) and valence of the compound released from the device, the ability to estimate the dose of the compound released from the device using biomonitoring data, the need to account for local effects at the implant site as well as systemic effects at target organs distant to the implant. The need for new approaches to assess the toxicity of novel metallic alloys and biodegradable metallic materials is also explored.