Physical Properties, Toxicity, and Physiological Effects of Magnets

The use of magnets has been a part of human civilization since antiquity. The ancient Greeks and Chinese civilizations were among the first to harness the usefulness of magnetic properties. While magnets played an important role in these early civilizations, their usefulness in the modern society is even more significant. Early industrial magnets were transition metal-based, which, while useful, had many inherent chemical flaws. The incorporation of rare-earth elements (REE) allowed them to become stronger and more resistant to demagnetization. The most abundantly used magnet in both industrial and medical applications is neodymium-iron-boron (Nd-Fe-B). This compound has high energy product and coercivity. While elemental neodymium is cytotoxic and, if untreated, vulnerable to environmental corrosion, properly coated Nd-Fe-B magnets can be extremely useful in the medical and surgical world. As with any new technology, fully understanding its properties and potential side effects is crucial for safe usage in patients. This chapter provides an introductory overview of the properties, toxicity, and potential adverse effects of magnets in surgery.