Innovative Nitinol Lumbar Vertebral Implants: Enhancing Biocompatibility and Mechanical Properties through Advanced Braiding Techniques

Abstract

The increasing occurrence of orthopedic disorders calls for advancements in techniques and implant technologies. The sensitive nature of the spinal cord highlights the need for implants with specific mechanical and biological properties that imitate those of bone. Nitinol alloy, known for its super-elasticity, bone-like elastic modulus, and excellent compatibility with living tissues is emerging as a favored material for orthopedic implants. In this research, a nitinol lumbar vertebral implant was created using a two-step procedure involving rod fabrication through sintering and braiding techniques focusing on assessing the effects of incorporating braiding into the structure. This method aimed to achieve both mechanical and biological properties simultaneously. In previous techniques, there was a greater focus on one of these properties. However, in this approach, the addition of the braid was an innovative way to append and enhance the biological properties. Examination under Scanning Electron Microscopy revealed a pore size of 310 micrometers in the samples while Atomic Force Microscopy showed a roughness of 971.1 nm both properties are proper for bone cells. Corrosion resistance was evaluated using Electrochemical Impedance Spectroscopy and the measured amount was 7366 ohm.cm2. Biological tests confirmed that the samples were biocompatible and non-toxic, with a cell viability rate of 95.1% observed over a period of 21 days. The development of this type of implant aims to improve the treatment outcomes for vertebral area surgeries.