The ESP disc prosthesis was designed for both lumbar and cervical disc replacement. They are made of 2 titanium alloy end-plates with an elastomeric core that provides cushion and functions like a real human disc. The spikes on the outer surfaces of the end-plates improve primary fixation until the bone has developed a solid bond to the disc. The combination of a hydroxyapatite (HA) coating on top of a T40 rough surface provides an excellent bonding surface for bone ongrowth. The titanium alloy used for the end plates allows clear medical imaging and guarantees good bony fixation over time.