Facet joint replacement instruments and methods

A system for replacing at least a portion of a natural facet joint that controls motion between a first vertebra and a second vertebra, the system comprising:

• a first fixation member implantable in a pedicle of the second vertebra;
• and
• an inferior facet joint implant comprising:
• an inferior articular body including an inferior articular surface having a shape that mimics a shape of a natural inferior articular surface of the second vertebra;
• an inferior strut formed separately from the inferior articular surface, the inferior strut comprising a first end and a second end, wherein the first end is securable to the fixation member and the second end is received in the inferior articular body;
• an attachment mechanism comprising a threaded expansion portion, a split shell having at least one lobe, and a nut, wherein the attachment mechanism is received in the inferior articular body;
• a second fixation member implantable in a pedicle of the second vertebra;
• and
• a second inferior facet joint implant comprising:
• a second inferior articular body including a second inferior articular surface shaped to replace a second natural inferior articular surface of the second vertebra, wherein the second inferior articular surface makes up at least part of a second outer surface of the second inferior articular body;
• a second inferior strut formed separately from the second inferior articular surface, the second inferior strut comprising a first end and a second end, wherein the first end is securable to the second fixation member and the second end is received in the second inferior articular body;
• and
• a second attachment mechanism comprising a second threaded expansion portion, a second split shell and a second nut.

A system for replacing at least a portion of a natural facet joint that controls motion between a first vertebra and a second vertebra, the system comprising:

• a first fixation member implantable in a pedicle of the second vertebra;
• and
• an inferior facet joint implant comprising:
• an inferior articular body including an inferior articular surface having a shape that mimics a shape of a natural inferior facet articular surface of the second vertebra;
• an inferior strut formed separately from the inferior articular surface, the inferior strut comprising a first end and a second end, wherein the first end is securable to the fixation member and the second end is received in the inferior articular body;
• and
• an attachment mechanism comprising a threaded expansion portion and a split shell having at least one lobe for receiving the threaded expansion portion therein, the attachment mechanism further comprising an adjustable configuration in which the inferior articular body is connected to the second end of the inferior strut in a manner that permits relative rotation between the inferior articular body and the second end of the inferior strut about three orthogonal axes, and a locked configuration in which the inferior articular body is rigidly secured to the second end of the inferior strut.