An apparatus and method are provided that allow for the realignment and stabilization of adjacent vertebrae. An implant of this invention both repositions adjacent vertebrae and remains in situ to maintain a new position. The implant has an upper half and a lower half, which are interlocked such that they can slide horizontally with respect to each other. Movement of the implant halves and their respective positions are controlled by a reduction bar and reduction rod in combination with an internal locking block within the implant. The reduction rod, being connected to a lower half and placed adjacent to the upper half, is rotated to bring the implant halves into alignment. The internal locking block engages to permanently hold the alignment and maintain the new position. A release mechanism for the internal locking block allows for readjustment of the implant halves and realignment of the vertebrae.