A spinal spacer includes a first plate, a second plate and a middle plate. The first and second plates are in one stack and spaced from each other with a distance. The middle plate is located between the first plate and the second plate, wherein the middle plate connects with the first plate and forms a first gap, and connects with the second plate and forms a second gap. The first plate and the second plate can move relative to the middle plate which leads to deformation of gaps
