The Characteristics of Nitinol in Spinal Implant Manufacturing

Due to the increasing number of diseases related to the spine, we expect to see more research on the implants used in this area. These implants should have features such as strength, fatigue resistance, chemical stability and biocompatibility, which fortunately are seen in an alloy called nitinol. In this study, six lumbar vertebral implants were made of nitinol and these samples been studied by some experiments such as: X-ray diffraction and biocompatibility (evaluation of cytotoxicity by MTT assay). Finally, we came to the conclusion that the mentioned alloy with suitable microstructure is appropriate for medical applications specially as an orthopedic implant. According to the X-ray diffraction pattern, the samples have austenitic structures in the room temperature and the predominant phase of the porous sample is B2-NiTi. Since the sample should be biocompatible after placement in the body and should not cause an immune system reaction, this test was also examined and the samples were tested in vitro with an MTT kit and the biocompatibility was assessed. The results of biocompatibility tests also indicate the suitability of the implant in terms of cellular characteristics. These properties have made this alloy superior to other alloys in orthopedic implant utilization, especially in areas under continuous loading. It is hoped that the construction of this type of implant will pave the way for facilitating the treatment of spinal abnormalities.