The intervertebral stabilization device (12, 170) preferably includes a planarspring (20, 180) enclosed within a housing (22, 172). The housing (122, 172) isjoined to an articulation component (24, 25, 174, 175) at either end, and the articulationcomponents (24, 25, 174, 175) have couplings (28, 178) connectable to anchoringcomponents (19) which are securable to adjacent vertebrae. The planar spring(20, 180) can flex and retract providing relative motion between the adjacentvertebrae. The articulation components (24, 25, 174, 175) are ball and socketjoints which allow the entire assembly to flexibly follow the curvature of thespine. A fusion rod (162) with articulation components and couplings (164) ateither end may be substituted for the spring device. The couplings enable interchangeabilitybetween a fusion rod (162) assembly and spring assembly (12, 170).
