Metals
Surgical instruments' history spans several centuries, even millenniums. Ancient Egyptians and Romans formed cutting and pulling instruments out of wood, bone and flint. Metals have been used in blades, handles and the cutting edges of shears and scissors for centuries as well. As alloys and metal smelting techniques improved, so did the quality of surgical instruments. The use of shear steel, named because it was used in manufacturing surgical instruments with blades, was popular before and during the first half of the 1700s. The drawback to shear steel was that the quality was unreliable and the blades broke easily. In the 1750s in England, stronger steel was developed at refineries that raised the shear steel temperatures to 1600 degrees Celsius. Once liquefied, the steel was poured into molds, becoming cast steel. Cast steel was the precursor of today's carbon steel. Carbon steel can be sharpened to a more exact degree than stainless steel, but it lacks stainless steel's ability to remain rust-free unless carefully kept from humidity. Modern surgical instruments such as scalpels are disposable and can have interchangeable blades.
Handles and Probes
Metals like copper and brass can be plated with silver and chromium. These metals are still used for malleable probes and hollow tubes. They are also used in the hollow handles of retractors and scraping instruments called raspatories. Another metal commonly found in the handles of delicate and high-precision surgical tools is titanium. Titanium is used because of its light weight and is non-reactive in human tissue. Another lightweight material, alloyed aluminum, is sometimes used for surgical instruments such as probes and dilators. More often, though, stainless steel is used in modern surgical instruments.
Today's Standards
Today, organizations such as the International Organization for Standardization (ISO) classifies and advises on which grade of stainless steel is appropriate for distinct types of surgical instruments. ISO also advises on tempering steel and the rust and corrosion processes on the different grades available. ISO also makes available testing standards and procedures for developing metal surgical instruments. Advancing technology allows surgical instruments to be manufactured for single or multiple uses, and new materials are also being explored, such as the use of specially hardened plastics for lancet and needle use.
