Posterior spinal device and method

Abstract

An intervertebral joint assembly includes an upper support and a lower support, each of which has two or more components. The upper and lower support components are arranged in situ to form the upper and lower supports, respectively. By arranging the supports in situ, the supports can be introduced from the back of the patient, for example with an arthroscope. Each of the upper and lower supports has a surface adapted to engage a vertebra and a surface adapted to engage the other support or an intermediate member to form an articulate joint which articulates the joint assembly. In some embodiments, the components of the upper and lower supports are assembled in situ, for example with pivoting, telescoping or bending, to form the upper and lower supports, respectively. The supports can be attached to vertebrae with pedicles screws, and/or other anchors attached to the supports.

What is claimed is: 
     
       1. A method for introducing a joint assembly to an intervertebral space between a pair of vertebral bodies of a patient, said method comprising:
 introducing upper support components interconnected by pivot joints into a surgical site; 
 arranging the upper support components interconnected by the pivot joints in situ into an upper support; 
 introducing lower support components into the surgical site; and 
 arranging the lower support components in situ into a lower support, wherein the upper and lower support components are introduced from a posterior approach of the patient and distal components are pivoted about the pivot joints toward proximal components to form the supports and wherein the upper support and the lower support are arranged to articulate with respect to one another, wherein the distal components are inserted at least partially into the intervertebral space before the proximal components, and wherein the upper and lower components each comprise a middle component folded under the proximal component and wherein the distal components are pivoted toward the proximal components before the middle components are unfolded from the proximal components. 
 
     
     
       2. The method as in  claim 1 , further comprising attaching the upper support or the lower support to bone anchors. 
     
     
       3. The method as in  claim 1 , wherein the components of the upper and lower supports are introduced and arranged together. 
     
     
       4. The method as in  claim 1 , wherein the components of each support are arranged by pivoting one or more elongate components of each support from a first elongate narrow profile configuration to a second wide profile configuration to assemble each support. 
     
     
       5. The method as in  claim 4  wherein at least one gear on each support is rotated to pivot the one or more components on each support. 
     
     
       6. The method of  claim 1 , wherein the lower support components are connected with joints and wherein the lower support components are arranged in situ to form the lower support by articulating the upper support components about the joints. 
     
     
       7. A method for introducing a joint assembly to an intervertebral space between a pair of vertebral bodies of a patient, said method comprising:
 introducing upper support components into a surgical site; 
 arranging the upper support components in situ into an upper support; 
 introducing lower support components into the surgical site; 
 arranging the lower support components in situ into a lower support, wherein the upper and lower support components are introduced from a posterior approach of the patient and distal components are pivoted toward proximal components to form the supports and wherein the upper support and the lower support are arranged to articulate with respect to one another, wherein the upper support components are connected with joints, wherein the upper support components are arranged in situ to form the upper support by articulating the upper support components about the joints, wherein the distal components are inserted at least partially into the intervertebral space before the proximal components, and wherein the upper and lower components each comprise a middle component folded under the proximal component and wherein the distal components are pivoted toward the proximal components before the middle components are unfolded from the proximal components. 
 
     
     
       8. The method of  claim 7 , wherein the upper support components are connected to one another by pivot joints prior to introduction into the intervertebral space. 
     
     
       9. A method for deploying an intervertebral implant in situ, the method comprising:
 performing a discectomy of an intervertebral disc space by removing a portion of an annulus of a natural disc to form an opening into the disc space, removing the natural disc and shaping the annulus to guide an intervertebral implant;   providing an intervertebral implant comprising upper and lower vertebral body support surfaces, a first segment, and a second segment pivotally connected to the first segment, wherein the intervertebral implant is expandable from an insertion configuration in which axes of the first and second segments are substantially aligned to an implanted configuration wider than the insertion configuration;   providing an insertion instrument removably attached to the intervertebral implant; and   introducing the intervertebral implant into the intervertebral space in the insertion configuration with the insertion instrument;   guiding the intervertebral implant into the evacuated disc space with the annulus shaped during the discectomy;   pivoting the second segment with respect to the first segment to deploy the intervertebral implant from the insertion configuration to the implanted configuration; and   detaching the insertion instrument from the intervertebral implant in the implanted configuration.   
     
     
       10. The method of claim 9, wherein the insertion instrument is removably attached to a first end of the first segment and the second segment is pivotally attached to the first segment at a second end of the first segment. 
     
     
       11. The method of claim 9 or 10, wherein the second segment is pivotally connected to the first segment about a first pivot axis which is substantially perpendicular to the upper and lower vertebral body support surfaces. 
     
     
       12. The method of claim 9, wherein the intervertebral implant is inserted into the intervertebral space from an opening in the spinal disc annulus posteriorly. 
     
     
       13. The method of claim 9, wherein the second segment pivots about 90 degrees with respect to the first segment when pivoting from the insertion configuration to the implanted configuration. 
     
     
       14. The method of claim 9, wherein the pivoting is limited by a first stop which limits the pivoting motion of the second segment with respect to the first segment. 
     
     
       15. The method of claim 9, wherein the first and second segments are retained in the insertion configuration by the insertion instrument while the implantable member is inserted into the intervertebral space. 
     
     
       16. The method of claim 9, wherein the intervertebral implant is a posterior intervertebral implant introduced into the intervertebral space from a posterior lateral approach. 
     
     
       17. The method of claim 9, wherein the intervertebral implant is inserted through a first opening in the spinal disc annulus, and wherein the spinal disc annulus is penetrated to form another opening away from the first opening. 
     
     
       18. The method of claim 17, wherein a distraction tool is inserted through the second opening to distract adjacent vertebrae while the intervertebral implant is introduced into the intervertebral space through the first opening. 
     
     
       19. The method of claim 9, wherein the intervertebral implant is configured to be implanted from the back of the patient into the intervertebral space and when implanted fits entirely within the intervertebral space. 
     
     
       20. The method of claim 9, wherein the intervertebral implant includes at least one anchor structure on each of the upper and lower vertebral body support surfaces. 
     
     
       21. The method of claim 20, wherein the anchor structure comprises protrusions adapted to engage vertebra when the intervertebral implant is inserted into the intervertebral space. 
     
     
       22. A method for deploying an intervertebral implant in situ, the method comprising:
 providing an intervertebral implant comprising upper and lower vertebral body support surfaces, a first segment and a second segment pivotally connected to one another about a first pivot axis which is substantially perpendicular to the upper and lower vertebral body support surfaces;   providing an insertion instrument removably attached to the intervertebral implant at an end of the first segment opposite the first pivot; and   introducing the intervertebral implant into an intervertebral space in an insertion configuration with the insertion instrument;   pivoting the second segment with respect to the first segment to deploy the intervertebral implant from the insertion configuration to an implanted configuration in which the implant is wider than in the insertion configuration;   detaching the insertion instrument from the intervertebral implant in the implanted configuration; and   articulating the upper and lower vertebral body support surfaces with respect to one another after insertion.   
     
     
       23. The method of claim 22, wherein the step of articulating is performed with the intervertebral implant in the implanted configuration. 
     
     
       24. The method of claim 23, wherein the articulating is performed in the flexion/extension direction. 
     
     
       25. The method of claim 22, further comprising a step of performing a discectomy of the intervertebral space by removing a portion of an annulus of a natural disc to form an opening into the disc space, wherein the discectomy includes removing the natural disc and shaping the annulus to guide the intervertebral implant during deployment into the evacuated space. 
     
     
       26. The method of claim 25, wherein the intervertebral implant is press fit anteriorly into the annulus so as to resist rotation of the intervertebral implant within the intervertebral space. 
     
     
       27. The method of claim 22, wherein the second segment pivots about 90 degrees with respect to the first segment when pivoting from the insertion configuration to the implanted configuration. 
     
     
       28. The method of claim 22, wherein the pivoting is limited by a first stop which limits the pivoting motion of the second segment with respect to the first segment. 
     
     
       29. The method of claim 22, wherein the first and second segments are retained in the insertion configuration by the insertion instrument while the intervertebral implant is inserted into the intervertebral space. 
     
     
       30. The method of claim 22, wherein the intervertebral implant is a posterior intervertebral implant introduced into the intervertebral space from a posterior lateral approach. 
     
     
       31. The method of claim 22, wherein the intervertebral implant includes at least one anchor structure on each of the upper and lower vertebral body support surfaces. 
     
     
       32. The method of claim 31, wherein the anchor structure comprises protrusions adapted to engage vertebra when the intervertebral implant is inserted into the intervertebral space.