Medical Device Link.

Originally Published MDDI December 2001

Shape-memory alloy constructed without nickel. A titanium-based alloy is made without nickel to increase its manufacturability and reduce concerns about biocompatibility. The material, produced by Memry Corp. (Bethel, CT; 203/739-1100), offers elasticity in applications for which allergies prohibit the use of conventional shape-memory metals. It is also easy to weld and join, and it has a strain recovery of 3.5%. The material can be used for orthodontic devices, implantable surgical devices, and nonimplantable surgical devices. Because it is biocompatible and more elastic than regular titanium, it can be used to make orthopedic devices as well.

Adhesive designed for bonding metal. A methacrylate adhesive provides a combination of high strength, fatigue endurance, impact resistance, and toughness. Developed for use on metal and other substrates, the MA820 two-part adhesive requires no primer and little or no surface preparation on most substrates. It takes the form of a low-odor, nonsagging gel with good tolerance to off-ratio mixing and offers a working time of 4–6 minutes. In 30–35 minutes, the gel achieves 75% of its ultimate strength. It cures with no surface tack. MA820, manufactured by ITW Plexus (Danvers, MA; 978/777-1100), can be used on stainless steel, aluminum, thermoplastics, and composites.

High-consistency elastomers available for a wide range of applications. A family of versatile elastomers was designed for optimal performance. VersaSil³, produced by NuSil Technology (Carpinteria, CA; 805/684-8780), includes three base stocks, which, when vulcanized, produce tough, durable elastomers with nominal Shore-A durometers of 30, 50, and 70, respectively. The base stocks may also be blended to produce elastomers of intermediate durometer. VersaSil³ was developed for volume users who require maximum versatility. Its applications include extrusion, transfer and compression molding, and calendering. The elastomers' advantages include translucency, variable table life, wide processing parameters, high tear strength, low cure temperatures, and relatively low cost, among others.

Fine wire is coated with PTFE. California Fine Wire (CFW, Grover Beach, CA; 805/489-5144) coats very thin wire with PTFE for use in medical and other applications. Next-generation medical applications for PTFE-coated wire include catheters for inserting computer chips, probes, sensors, monitors, and remote devices into the body for treatment of brain or organ problems, according to the company. Because it is inert, PTFE does not react to chemical or biological agents. This characteristic renders PTFE-coated devices useful in invasive surgery because they are less prone to rejection by the human body than other devices. According to CFW, bone staples, wires, plates, and pacemaker wires can all be coated with PTFE.

Bone-bonding material receives CE mark. A high-strength material designed to aid in the treatment of patients with osteoporotic fractures has earned European regulatory approval. Cortoss, a product of Orthovita (Malvern, PA; 610/640-1775), mimics the strength and flexibility of human cortical bone. The synthetic bone material is suited for the fixture of bone screws that have difficulty maintaining stability in weak bone. Cortical bone is often surgically repaired using wires, hooks, metal plates, and screws, which help align the bone and keep it anchored. When bone strength is impaired—as is the case in osteoarthritic-fracture patients—the screws and hardware normally used in treatment may be unable to remain in place in the bone. Traditionally in such cases, a larger screw or longer device is used to replace a loose screw. Cortoss was developed to help bone screws maintain stability in osteoporotic bone, with the goal of helping patients heal faster and avoid repeated surgery.

Copyright ©2001 Medical Device & Diagnostic Industry