Expandable intervertebral spacer

Abstract

An expandable spacer, comprising: an axial tube having a surface, a proximal end and a distal end and a length, wherein, said surface defines a plurality of slits, said plurality of slits defining at least two axially displaced extensions, such that when said tube is axially compressed, said extensions extend out of said surface and define a geometry of an expanded spacer. Preferably the spacer is adapted to be inserted between two spinal vertebrae of a human.

The invention claimed is: 
     
       1. Instrumentation for treatment of the spine, comprising:
 an elongate member extending along a longitudinal axis and including a deformable distal end portion having an expandable length along said longitudinal axis and defining an initial configuration for placement adjacent a spinal structure and a deformed configuration defining a plurality of transverse projections, wherein each of said transverse projections is offset from an adjacent one of said transverse projections along said longitudinal axis, said transverse projections being positioned axially adjacent one another to define an expanded height of said deformable distal end portion along said expandable length for transverse engagement with at least a portion of the spinal structure, 
 wherein said deformable distal end portion is at least partially formed of a flexible material and said deformable distal end portion is reformed from said initial configuration toward said deformed configuration in response to the imposition of stress, and is reformed toward said initial configuration upon removal of said stress, and 
 wherein between three and eight of said transverse projections define an expanded height of said deformable distal end portion extending entirely over said expandable length. 
 
     
     
       2. The instrumentation of  claim 1 , wherein said deformed configuration defines a pair of said transverse projections disposed generally opposite one another. 
     
     
       3. The instrumentation of  claim 1 , wherein said deformed configuration results from a mechanically induced force. 
     
     
       4. The instrumentation of  claim 3 , wherein said deformable distal end portion comprises a first member and a second member engaged with said first member; and
 wherein said second member is reformed from said initial configuration toward said deformed configuration by relative displacement between said first and second members. 
 
     
     
       5. The instrumentation of  claim 4 , wherein said relative displacement between said first member and said second member is relative linear displacement. 
     
     
       6. The instrumentation of  claim 4 , further comprising an actuator mechanism operably coupled to said first and second members to impart said relative displacement therebetween. 
     
     
       7. The instrumentation of  claim 1 , wherein said deformable distal end portion is at least partially formed of a relatively elastic material. 
     
     
       8. The instrumentation of  claim 7 , wherein said relatively elastic material is a shape-memory material. 
     
     
       9. The instrumentation of  claim 1 , wherein said transverse engagement comprises interbody distraction of a vertebral body. 
     
     
       10. Instrumentation for treatment of the spine, comprising: a first member;
 a second member having a distal end portion engaged with said first member, said distal end portion having an expandable length along a longitudinal axis and defining an initial 
 configuration for placement adjacent a spinal structure and an expanded configuration including a plurality of transverse projections, wherein each of said transverse projections is offset from an adjacent one of said transverse projections along said longitudinal axis, said transverse projections being positioned axially adjacent one another to define an expanded height of said distal end portion along said expandable length for transverse engagement with at least a portion of the spinal structure; 
 wherein relative displacement between said first and second members causes said distal end portion to reform from said initial configuration toward said expanded configuration and said instrumentation further comprises an actuator mechanism coupled between said first and second members and being operable to impart said relative displacement therebetween, and 
 wherein said deformable distal end portion defines a non-expanded height when in said initial configuration and wherein said expanded height is at least two times larger than said non-expanded height. 
 
     
     
       11. The instrumentation of  claim 10 , wherein said actuator mechanism is operable to reform said distal end portion of said second member from said expanded configuration back toward said initial configuration. 
     
     
       12. The instrumentation of  claim 10 , wherein said distal end portion of said second member is at least partially formed of a relatively elastic material to facilitate reformation from said initial configuration to said expanded configuration and back toward said initial configuration. 
     
     
       13. The instrumentation of  claim 10 , wherein said plurality of transverse projections each comprises an outward deformation. 
     
     
       14. The instrumentation of  claim 13 , wherein said distal end portion of said second member includes a pair of said outward deformations positioned generally opposite one another when in said expanded configuration. 
     
     
       15. The instrumentation of  claim 10 , wherein said distal end portion of said second member comprises at least one flexible strip of material, said flexible strip of material buckling outwardly in response to said relative displacement between said first and second members to form said plurality of transverse projections. 
     
     
       16. The instrumentation of  claim 15 , wherein outward buckling of said flexible strip of material occurs in a predetermined direction. 
     
     
       17. The instrumentation of  claim 15 , wherein said distal end portion of said second member comprises a pair of said flexible strips of material disposed generally opposite one another, said flexible strips of material buckling outwardly in response to said relative displacement between said first and second members to form a pair of said transverse projections disposed generally opposite one another. 
     
     
       18. The instrumentation of  claim 15 , wherein said flexible strip of material has a predetermined shape to provide controlled outward buckling. 
     
     
       19. The instrumentation of  claim 10 , wherein said distal end portion of said second member defines a plurality of slots, said slots facilitating outward buckling of said distal end portion in response to said relative displacement between said first and second members. 
     
     
       20. The instrumentation of  claim 19 , wherein each of said plurality of slots has a predetermined shape to provide controlled outward buckling. 
     
     
       21. The instrumentation of  claim 10 , wherein reformation between said initial configuration and said expanded configuration is directionally-controlled. 
     
     
       22. The instrumentation of  claim 10 , wherein said distal end portion of said second member comprises at least one flexible strip of material, said flexible strip of material buckling outwardly in response to said relative displacement between said first and second members to form said expanded configuration, said flexible strip of material having a predetermined shape to provide controlled outward buckling, said predetermined shape including a series of arcuate portions. 
     
     
       23. The instrumentation of  claim 10 , wherein said distal end portion of said second member defines a plurality of slots, said slots facilitating outward buckling of said distal end portion in response to said relative displacement between said first and second members, each of said plurality of slots has a predetermined shape to provide controlled outward buckling, said predetermined shape being at least partially comprised of an hour-glass shape. 
     
     
       24. The instrumentation of  claim 1 , wherein said deformable distal end portion includes four of said transverse projections that are axially offset from an adjacent one of said transverse projections along said longitudinal axis. 
     
     
       25. The instrumentation of  claim 1 , wherein said expanded height of said transverse projections define a uniform expanded height over said expandable length. 
     
     
       26. The instrumentation of  claim 1 , wherein said deformable distal end portion comprises a non-expanded height when in said initial configuration; and
 wherein said expanded height is at least two times larger than said non-expanded height. 
 
     
     
       27. The instrumentation of  claim 1 , wherein said deformable distal end portion defines a non-expanded height when in said initial configuration; and
 wherein said expanded height is at least three times larger than said non-expanded height.   
     
     
       28. The instrumentation of  claim 1 , wherein said deformable distal end portion defines a non-expanded height when in said initial configuration; and
 wherein said expanded height is at least four times larger than said non-expanded height.   
     
     
       29. The instrumentation of  claim 1 , wherein said deformable distal end portion defines a non-expanded height when in said initial configuration; and
 wherein said expanded height is at least five times larger than said non-expanded height.   
     
     
       30. The instrumentation of  claim 1 , wherein at least fifty percent of said deformable distal end portion is covered by said plurality of transverse projections. 
     
     
       31. The instrumentation of  claim 1 , wherein at least seventy percent of said expandable length is covered by said at least three of said transverse projections. 
     
     
       32. The instrumentation of  claim 1 , wherein said transverse projections include outer tips defining said expanded height, said tips having a curved outer surface configured for engagement with the spinal structure. 
     
     
       33. The instrumentation of  claim 1 , wherein said transverse projections are evenly distributed along said longitudinal axis and said expandable length. 
     
     
       34. The instrumentation of  claim 1 , wherein said expandable length includes non-expandable portions extending between adjacent pairs of said transverse projections, each said transverse projections having an axial thickness that is greater than an axial length of said non-expandable portions. 
     
     
       35. The instrumentation of  claim 1 , wherein said transverse projections are positioned proximately adjacent one another along said expandable length. 
     
     
       36. The instrumentation of  claim 1 , wherein said transverse projections are positioned immediately adjacent one another along said expandable length. 
     
     
       37. The instrumentation of  claim 10 , wherein said distal end portion includes four of said transverse projections that are each axially offset from an adjacent one of said transverse projections along said longitudinal axis. 
     
     
       38. The instrumentation of  claim 10 , wherein eight of said transverse projections define an expanded height of said distal end portion extending entirely over said expandable length. 
     
     
       39. The instrumentation of  claim 10 , wherein said expanded height of said transverse projections comprises a uniform expanded height over said expandable length. 
     
     
       40. The instrumentation of  claim 10 ,
 wherein said expanded height is at least three times larger than said non-expanded height.   
     
     
       41. The instrumentation of  claim 10 ,
 wherein said expanded height is at least four times larger than said non-expanded height.   
     
     
       42. The instrumentation of  claim 10 ,
 wherein said expanded height is at least five times larger than said non-expanded height.   
     
     
       43. The instrumentation of  claim 10 , wherein at least fifty percent of said distal end portion is covered by said plurality of transverse projections. 
     
     
       44. The instrumentation of  claim 10 , wherein at least seventy percent of said expandable length is covered by said at least three of said transverse projections. 
     
     
       45. The instrumentation of  claim 10 , wherein said transverse projections include outer tips defining said expanded height, said tips having a curved outer surface configured for engagement with the spinal structure. 
     
     
       46. The instrumentation of  claim 10 , wherein said transverse projections are evenly distributed along said longitudinal axis and said expandable length. 
     
     
       47. The instrumentation of  claim 10 , wherein said expandable length includes non-expandable portions extending between adjacent pairs of said transverse projections, said transverse projections each having an axial thickness that is greater than an axial length of said non-expandable portions. 
     
     
       48. The instrumentation of  claim 10 , wherein said transverse projections are positioned proximately adjacent one another along said expandable length. 
     
     
       49. The instrumentation of  claim 10 , wherein said transverse projections are positioned immediately adjacent one another along said expandable length. 
     
     
       50. The instrumentation of  claim 1 , wherein said plurality of transverse projections comprises three of said transverse projections. 
     
     
       51. The instrumentation of  claim 1 , wherein said plurality of transverse projections comprises eight of said transverse projections. 
     
     
       52. The instrumentation of  claim 10 , wherein between three and eight of said transverse projections define an expanded height of said deformable distal end portion extending entirely over said expandable length. 
     
     
       53. The instrumentation of  claim 52 , wherein said plurality of transverse projections comprises an odd number of said transverse projections. 
     
     
       54. The instrumentation of  claim 52 , wherein said plurality of transverse projections comprises eight of said transverse projections. 
     
     
       55. An expandable implant for use in a human spine comprising:
 a first member;   a second member having a proximal end portion and a distal end portion, the distal end portion being engaged with the first member and including a body portion having an upper surface, a longitudinal axis, and an expandable length along the longitudinal axis for engagement with a portion of a spinal structure of the human spine, the upper surface having a plurality of elevation portions being defined in the upper surface, each of the plurality of elevation portions having opposing first and second sides and opposing first and second ends, and a first one and a second one of the plurality of elevation portions each being configured to be expanded away from the longitudinal axis in a direction substantially transverse to the longitudinal axis from an initial configuration to respectively form a first transverse projection and a second transverse projection in an expanded configuration, the opposing first and second sides of each of the plurality of elevation portions being formed by opposing first and second slits defined in at least the upper surface, the opposing first and second slits of each of the plurality of elevation portions extending at least between the opposing first and second ends, the first transverse projection and the second transverse projection being axially adjacent one another, and being offset from one another along the longitudinal axis; and   an actuator mechanism coupled between the first member and the second member, the actuator mechanism being operable to impart relative displacement between the first member and the second member;   wherein the relative displacement of the first member and the second member causes the first one and a second one of the plurality of elevation portions to expand from the initial configuration to the expanded configuration; and   wherein, when the first one and a second one of the plurality of elevation portions are in the initial configuration, the distal end portion has a non-expanded height, and, when the first one and the second one of the plurality of elevation portions are in the expanded configuration, the distal end portion has an expanded height, the expanded height being at least two times larger than the non-expanded height.   
     
     
       56. An expandable implant for use in a human spine comprising:
 a first member;   a second member having a first proximal end portion and a second distal end portion, the second distal end portion being engaged with the first member and including a body portion having an upper surface, a longitudinal axis, and an expandable length along the longitudinal axis, the upper surface including at least a first elevation portion and a second elevation portion, each of the first elevation portion and the second elevation portion including opposing first and second sides and opposing first and second ends, the first elevation portion and the second elevation portion each being moveable from an initial unexpanded position substantially aligned with the longitudinal axis to an expanded position substantially transverse to the longitudinal axis to respectively form a first transverse projection and a second transverse projection, the first transverse projection and the second transverse projection being axially adjacent one another, and being offset from one another along the longitudinal axis;   an actuator mechanism coupled between the first member and the second member, the actuator mechanism being operable to impart relative displacement between the first member and the second member;   wherein the relative displacement of the first member and the second member causes the first elevation portion and the second elevation portion to expand from the initial unexpanded configuration to the expanded configuration; and   wherein, when the first elevation portion and the second elevation portion are in the initial unexpanded configuration, the second distal end portion has a non-expanded height, and, when the first elevation portion and the second elevation portion are in the expanded configuration, the second distal end portion has an expanded height, the expanded height being at least two times larger than the non-expanded height.