Medical-grade wire made from platinum and other precious metals helps to make diagnostic and surgical procedures simpler, safer and more effective. From catheter guide wires to pins in a knee joint to your child’s braces, the applications of these metals in wire form are limitless.
Medical device OEMs have exacting requirements for medical wire. Because it will contact human or animal tissue, medical wire must be intrinsically safe for invasive procedures or implantation. Medical wire must be lightweight, strong, rugged, flexible and able to retain its shape while subject to myriad conditions such as push/pull forces, repetitive movement, weight and temperature. And with more and more diagnostics and surgeries utilizing electrical-based instruments, conductivity is critical for medical wire.
Enter the precious metals, which are uniquely suited for medical applications. Platinum, palladium, gold and their alloys offer high melting points and are excellent electrical conductors. They are easily drawn into the thinnest diameters — as small as .001 in. (.0254mm) — while providing uniformity, pull and tensile strength, flexibility and durability. Precious metal wire is also radiopaque; visible under X-rays or a fluoroscope, making it relatively easy for the healthcare professional to position or locate a device during a procedure. Most importantly, precious metals are biocompatible with living tissues. They are nontoxic and do not cause an adverse reaction within the body.
Common varieties of medical wire include gold, platinum and platinum alloys with iridium, rhodium, nickel and tungsten, as well as nonprecious wires made of tantalum and stainless steel. The wire is typically drawn under high heat and extruded through a series of dies to achieve its desired final properties such as:
|Tensile Strength||maximum stress that the wire can withstand while being stretched or pulled before failing or breaking|
|Elongation||the increase in the gauge length of wire, measured after fracture of the test piece|
|Rated Load||maximum amount of force or weight that the wire can be expected to hold under normal use|
|Breaking Strength||load at which the wire breaks during a tensile or flex test|
Wire can be solid or cladded (coated). Finished wire is cut to length and packaged in coils, spools or flats. Customers choose from stock wire in standard diameters from .001” to .125”; stock alloys of gold, platinum, palladium and silver; or request custom fabrications. Depending on the application, medical wire can be fabricated to meet the exacting standards of NIST, ASTM or FDA.
ASTM International has established thousands of standards for the design and performance of medical devices, implants and components such as wire. These standards allow material and product manufacturers, medical labs and clinicians to evaluate devices for proper quality, workmanship and performance. Adopted worldwide, ASTM medical device standards cover the gamut of medicine, from the instruments used in specialized applications such as orthopedic, arthroscopic or cardiovascular, to biocompatibility and metallurgical standards for the metals themselves.
Two of the most familiar applications of medical wire are in cardiovascular medicine. A guide wire is used to lead a balloon catheter through a damaged vein to eliminate fatty deposits. Alternatively, pacemakers utilize wire leads for neuromodulation; they transmit electrical impulses through veins attached to the heart to stimulate and regulate the heartbeat. Neuromodulation is also used to treat chronic pain and has been adopted as a treatment for conditions such as depression, Parkinson ’s disease and epilepsy.
Everyone knows someone who has had wire ligatures — stitches or staples — after surgery on a broken bone. But the repaired bone itself may contain Kirschner (K-)pins, which are wire lengths drilled into the bone to stabilize it or join separated pieces.
Other applications include:
Dental braces (bands and anchoring wire)
Guide and feed-through wires for stents, laparoscopes and endoscopes
|Defibrillators (heart shocking coils)|
|Biosensors and monitors|
|Ophthalmic wire (speculums to hold eyes open)|
|Continuous glucose monitoring devices|
NuTEC Medical is an exclusive PGM (Platinum Group Metals) materials supplier to global Medical Device Manufacturing industries. Our product breadth, including wire, tubing, rod, strip and machine components, allows us to serve the demanding applications of cardiac rhythm devices, neuromodulation devices, cochlear implants, diagnostic equipment and various other medical submarket industries.