A posterior vertebral joint prosthesis is provided so that the left or right posterior vertebral joint prosthesis (1, 2) presents a smooth bearing surface (11, 11a, 11b, 17, 17a, 17b) and and which surface presents antero-posterior curvature....http://www.google.ca/patents/US7147664?utm_source=gb-gplus-sharePatent US7147664 - Posterior vertebral joint prosthesis
