Stubstad James A, Urbaniak James R, Kahn Paul: Prosthesis for spinal repair. Cutter Laboratories, Owen Wickersham & Erickson, February 25, 1975: US3867728 (1027 worldwide citation)

A shaped article comprising at least a core element having generally flat top and bottom surfaces, the core element being made of elastic polymer and preferably reinforced. Presently preferred forms of the article are those in which the core element has a covering element secured to one or, in some ...