Spinal prosthetic devices having selectable and/or changeable centers of
rotation are disclosed. In one aspect, a spinal prosthesis kit includes a
first component, a second component, and a plurality of inserts. The
first component has a first articulating surface that includes a first
articulating structure. The second component has a second articulating
surface with a recessed opening adapted to receive one of the plurality
of inserts. Each of the plurality of inserts includes a second
articulating structure adapted to moveably mate with the first
articulating structure. The second articulating structure is positioned
in a different location on each of the plurality of inserts. In some
embodiments, the articulating structures are moveably mating projections
and recesses. In another aspect, a revisable prosthetic device having a
first component, a second component, and an insert is provided.