[Advances on the study of movable artificial vertebral body]

At present, artificial vertebral implants have proven to be effective in the treatment of spinal tumors, infections, fractures and other diseases. However, the fusion artificial vertebral body can cause adjacent intervertebral joint degeneration and loss of original physiological curvature and activity. The movable artificial vertebral body can, to some extent, restore the normal physiological movement and reduce biomechanical changes of the spine, reducing the occurrence of complication. The design of movable artificial vertebral body is to equip movable device when the basis of reliable stability is obtained. According to its principle it can be divided into ball socket joint or elastic deformation. However the overall design of movable artificial vertebral body needs further improvement. Traditional mechanical processing methods are difficult to process complex prostheses and the agreement rate between traditional produced prostheses and lesions was low. While the emerging 3D printing technology can achieve individualized improvement of prosthesis, its slow rate and high cost need to be improved. The materials of movable artificial vertebral body includes metal, ceramics, biomaterials, high polymer materials and so on. Titanium alloy is the main material in metal materials, which is widely used, but its modulus of elasticity is still far from that of human bone and it lacks ideal bone fusion. Ceramic materials are rich in variety but fragile and poor in wear resistance. Biomaterials include autogenous bone, allogeneic bone, etc., with limited source and complicated operation. There are many kinds of polymer and biodegradable materials which obtain excellent and ideal properties. But their properties and applications need to be further studied. The movable artificial vertebral body still needs to be promoted and developed. The clinical experimental data is still insufficient, and long-term curative effect needs to be further observed and studied. This paper reviews the development, advantages, design, processing and materials of movable artificial vertebral bodies and provides useful reference for optimization design, processing and clinical application of movable artificial vertebral bodies.