Fig. 10
Total disc replacement (or disc arthroplasty). Lateral (a) and anteroposterior (b) radiographs demonstrate disc arthroplasty at C5-6 and C6-7 levels. There is also an anterior fusion/stabilization hardware with plates, screws, and an interbody spacer (arrowhead) at the C4-5 level. Disc prostheses (arrows) are composed of a core sandwiched between two metal plates that attach to the vertebral bodies. Ideally, the plates must be at the center of the vertebral body and parallel to each other. In this case, there is a slight anterior dislocation of the superior plate at C5-6 level (black arrow) and optimal positioning at the C6-7 level (thin arrow)