Biocompatibility of Nitinol

The unique properties of Nitinol have provided the enabling technology for many groundbreaking applications in the medical and dental industries. These applications have included everything from surgical tools to permanent implants, including implants within the bloodstream.

Two particularly successful Nitinol medical devices are the SIMON NITINOL FILTER^TM (SNF) and the Mitek(R) bone suture anchor. The SNF is an umbrella shaped device deployed via the shape memory effect to entrap blood clots in the vena cava. The SNF was developed in the 1970s and since that time has been implanted successfully in hundreds of patients.

Mitek(R) suture anchors have revolutionised the field of orthopedic surgery by providing a secure, stable attachment for tendons, ligaments, and other soft tissue to bone. Consisting of a titanium or Nitinol body with two or more arcs of Nitinol wire, the Mitek Anchor is inserted through a small incision into a hole drilled into the bone. Since its introduction in 1989 for shoulder surgery, use of the Mitek Anchor has been expanded to include 25 orthopaedic applications and one urological application.

The excellent biocompatibility, very high corrosion resistance, and excellent cytocompatibility of Nitinol has made these unique applications possible. The Nickel in Nitinol is chemically joined to the Titanium in a strong intermetallic bond, so the risk of reaction, even in patients with Nickel-sensitivity, is extremely low. Of course, the necessary regulatory approvals still must be received for each new application. For a more thorough review of the biocompatibility of Nitinol, please consult the references below.