Spinal facet implant with spherical implant apposition surface and bone bed and methods of use

A method for establishing a disposition of an implant for replacing a facet of a mammalian vertebra, the implant comprising an articulating surface and a coupling portion, the coupling portion having a bone engaging surface, wherein the articulating surface is shaped to articulate against a second facet surface, the method comprising:

• forming a semispherical resection in the vertebra;
• securing a fixation element to the vertebra, the fixation element having an end extending outward from the vertebra;
• after the securing step, introducing a fixation element engaging surface of the coupling portion over the outward extending end of the fixation element;
• positioning the bone engaging surface against the semispherical resection such that the articulating surface is positioned to articulate against a second facet;
• and
• securing the fixation element engaging surface to the outward extending end of the fixation element.

A method for establishing a disposition of an implant for replacing a facet of a mammalian vertebra, the implant comprising a curved articulating surface, an angled flat that extends from the rear of the curved articulating surface, and a semi-spherical bone engaging surface, wherein the angled flat is positioned between a back side of the curved articulating surface and the semi-spherical bone engaging surface, wherein the articulating surface is shaped to articulate against a second facet surface, the method comprising:

• implanting a fixation element into the vertebra, a portion of the fixation element extending outward from the vertebra in a relatively posterior direction, wherein the fixation element is radially expandable, wherein the fixation element comprises a central element on a distal most end of the fixation element and an expansion sleeve, wherein the central element is drawn outward relative to the expansion sleeve to cause radial expansion of the fixation element;
• introducing the bone engaging surface over the outward extending portion of the fixation element;
• positioning the bone engaging surface such that the articulating surface is positioned to articulate against the second facet surface;
• and
• securing the implant to the outward extending portion of the fixation element.