Prosthetic intervertebral discs
View Patent ↗Prosthetic intervertebral discs, systems including such prosthetic intervertebral discs, and methods for using the same are described. The subject prosthetic discs include upper and lower endplates separated by a compressible core member. The subject prosthetic discs exhibit stiffness in the vertical direction, torsional stiffness, bending stiffness in the saggital plane, and bending stiffness in the front plane, where the degree of these features can be controlled independently by adjusting the components, construction, and other features of the discs.
1. A prosthetic intervertebral disc comprising:
a first endplate including at least one fixation member selectively moveable from an undeployed state to a deployed state, the at least fixation member comprising at least one keel slidably engageable from an edge of the first endplate;
a second endplate attached either directly or indirectly to the first endplate in a substantially parallel relationship thereto; and
a core member positioned between the first and second endplates, and
wherein the at least one fixation member extends into an intervertebral surface when in the deployed state.
2. The prosthetic intervertebral disc of claim 1 , wherein the at least one keel has a generally triangular cross-sectional shape and the first endplate includes a slot having a generally trapezoidal cross-sectional shape for engaging the at least one keel.
3. The prosthetic intervertebral disc of claim 1 , wherein the first endplate has a generally curved cross-sectional shape.
4. The prosthetic intervertebral disc of claim 1 , wherein the at least one keel includes a base portion, an anchoring fin extending outward from an outer surface of the base portion, and an attachment member on another surface of the base portion, the attachment member configured to engage the first endplate.
5. The prosthetic intervertebral disc of claim 4 , wherein the base portion has a generally wedge shape to accommodate a lordosis angle upon implantation.
6. The prosthetic intervertebral disc of claim 1 , wherein the at least one fixation member in its deployed state extends outward from an outer surface of the first endplate.
7. The prosthetic intervertebral disc of claim 6 , wherein the at least one fixation member further comprises at least one retractable anchoring fin.
8. The prosthetic intervertebral disc of claim 7 , further comprising at least one fixed anchoring fin extending outward from an outer surface of the first endplate.
9. The prosthetic intervertebral disc of claim 8 , wherein the at least one fixed anchoring fin is oriented at a generally right angle relative to the at least one retractable anchoring fin.
10. The prosthetic intervertebral disc of claim 7 , wherein the at least one retractable anchoring fin is moved from its undeployed state to its deployed state by an expandable member located generally between the first endplate and the second endplate.
11. The prosthetic intervertebral disc of claim 7 , wherein the at least one retractable anchoring fin is moved from its undeployed state to its deployed state by a screw mechanism located generally between the first endplate and the second endplate.
12. The prosthetic intervertebral disc of claim 1 wherein the core member is compressible.
13. The prosthetic intervertebral disc of claim 1 wherein the core member comprises at least one polymeric elastomer.
14. A prosthetic intervertebral disc comprising:
a first endplate comprising an inner member and an outer member, with the inner member and the outer member being rotatable relative to one another, the rotation being in a substantially parallel relationship to the first endplate;
a second endplate attached either directly or indirectly to the first endplate; and
a core member positioned between the first and second endplates;
wherein rotation of the inner member relative to the outer member causes at least one fixation member to extend outward from the first endplate.
15. The prosthetic intervertebral disc of claim 14 , wherein the at least one fixation member comprises at least one threaded screw.
16. The prosthetic intervertebral disc of claim 15 , further comprising at least one opening formed in one of the inner member or the outer member, the at least one threaded screw being configured to travel within the at least one opening.
17. The prosthetic intervertebral disc of claim 16 , wherein the at least one opening is formed in the inner member of the first endplate.
18. The prosthetic intervertebral disc of claim 17 , wherein the outer member of the first endplate includes at least one threaded hole that is adapted to engage the threads of the at least one threaded screw to facilitate extension of the at least one threaded screw outward from the first endplate.
19. The prosthetic intervertebral disc of claim 18 , further comprising a plurality of fixation members extending outwardly from the first endplate.
20. The prosthetic intervertebral disc of claim 19 , further comprising a plurality of fixation members extending outwardly from the second endplate.
21. The prosthetic intervertebral disc of claim 14 wherein the second endplate is in a substantially parallel relationship to the first endplate.
22. The prosthetic intervertebral disc of claim 14 wherein the core member is compressible.
23. The prosthetic intervertebral disc of claim 14 wherein the core member comprises at least one polymeric elastomer.
24. A prosthetic intervertebral disc comprising:
a first endplate with an outer surface having an outer surface area for engaging a first vertebra;
a second endplate attached either directly or indirectly to the first endplate in a substantially parallel relationship thereto and having an outer surface with an outer surface area for engaging a second vertebra; and
a core member positioned between the first and second endplates;
wherein said first endplate includes a central portion and a first dropleaf side portion, the first dropleaf side portion having a first position in which it lies in a substantially different plane than the central portion, and a second position in which it lies in a substantially the same plane as the central portion and increases the outer surface area of the first endplate for engaging the first vertebra.
25. The prosthetic intervertebral disc of claim 24 further comprising a hinge connecting the first endplate's central portion and the first endplate's first dropleaf side portion.
26. The prosthetic intervertebral disc of claim 25 , wherein the first endplate has a second dropleaf side portion attached to the central portion, the second dropleaf side portion having a first position in which it lies in a substantially different plane than the central portion, and a second position in which it lies in a substantially the same plane as the central portion and increases the outer surface area of the first endplate for engaging the first vertebra.
27. The prosthetic intervertebral disc of claim 24 , wherein the second endplate includes a central portion attached to a first dropleaf side portion, the first dropleaf side portion having a first position in which it lies in a substantially different plane than the central portion, and a second position in which it lies in a substantially the same plane as the central portion and increases the outer surface area of the second endplate for engaging the second vertebra.
28. The prosthetic intervertebral disc of claim 12 , further comprising a spring extending between and attached to the first dropleaf side portions of each of the first endplate and the second endplate.
29. The prosthetic intervertebral disc of claim 28 , wherein the first dropleaf side portions of the first endplate and the second endplate each comprising a slot therein, each of the slots engageable with the spring.
30. The prosthetic intervertebral disc of claim 24 wherein the core member is compressible.
31. The prosthetic intervertebral disc of claim 24 wherein the core member comprises at least one polymeric elastomer.
32. The prosthetic intervertebral disc of claim 26 further comprising a hinge attaching the first endplate's second dropleaf side portion to the first endplate's central portion.
33. The prosthetic intervertebral disc of claim 27 further comprising a hinge attaching the second endplate's first dropleaf side portion to the second endplate's central portion.
34. The prosthetic intervertebral disc of claim 27 , wherein the second endplate has a second dropleaf side portion attached to the central portion by a second hinge, the second dropleaf side portion having a first position in which it lies in a substantially different plane than the central portion, and a second position in which it lies in substantially the same plane as the central portion and increases the outer surface area of the second endplate for engaging the second vertebra.
35. The prosthetic intervertebral disc of claim 34 further comprising a hinge attaching the second endplate's second dropleaf side portion to the second endplate's central portion.
36. A prosthetic intervertebral disc comprising:
a first endplate having at least one fixation member moveable from an undeployed state to a deployed state relative to the first endplate, the at least one fixation member being engageable with and extending into a vertebral surface when deployed;
a second endplate attached either directly or indirectly to the first endplate; and
a compressible core member positioned between the first and second endplates.
37. The prosthetic intervertebral disc of claim 36 wherein the core member comprises at least one polymeric elastomer.
38. The prosthetic intervertebral disc of claim 36 wherein the first endplate is in a substantially parallel relationship to the second endplate.
39. The prosthetic intervertebral disc of claim 36 wherein the at least one fixation member comprises at least one keel slidably engageable with the first endplate.
40. The prosthetic intervertebral disc of claim 39 wherein the at least one keel has a generally triangular cross-sectional shape and the first endplate includes a slot having a generally trapezoidal cross-sectional shape corresponding to the at least one keel's generally triangular cross-sectional shape, the slot for engaging the keel.
41. The prosthetic intervertebral disc of claim 36 wherein the first endplate has a generally curved cross-sectional shape.
42. The prosthetic intervertebral disc of claim 36 wherein the at least one keel includes a base portion, an anchoring fin extending outward from an outer surface of the base portion, and an attachment member on another surface of the base portion, the attachment member engageable with the first endplate.
43. The prosthetic intervertebral disc of claim 42 wherein the base portion has a generally wedge shape to accommodate a disc lordosis angle upon implantation.
44. The prosthetic intervertebral disc of claim 36 wherein the at least one fixation member in its deployed state extends outward from an outer surface of the first endplate.
45. The prosthetic intervertebral disc of claim 44 wherein the at least one fixation member comprises at least one retractable anchoring fin.
46. The prosthetic intervertebral disc of claim 45 further comprising at least one fixed anchoring fin extending outward from an outer surface of the first endplate.
47. The prosthetic intervertebral disc of claim 46 wherein the at least one fixed anchoring fin is oriented at a generally right angle relative to the retractable anchoring fin.
48. The prosthetic intervertebral disc of claim 45 wherein the at least one retractable anchoring fin is moved from its undeployed state to its deployed state by an expandable member located generally between the first endplate and the second endplate.
49. The prosthetic intervertebral disc of claim 48 wherein the at least one retractable anchoring fin is moved from its undeployed state to its deployed state by an inflatable member located generally between the first endplate and the second endplate.
50. The prosthetic intervertebral disc of claim 45 wherein the at least one retractable anchoring fin is moved from its undeployed state to its deployed state by a screw mechanism located generally between the first endplate and the second endplate.
51. The prosthetic intervertebral disc of claim 41 wherein the second endplate has a generally curved cross-sectional shape.
52. The prosthetic intervertebral disc of claim 44 wherein the second endplate's at least one fixation member comprises at least one retractable anchoring fin.
53. The prosthetic intervertebral disc of claim 52 further comprising at least one fixed anchoring fin extending outward from an outer surface of the second endplate.
54. A prosthetic intervertebral disc comprising:
a first endplate comprising an inner member and an outer member, the inner member and the outer member being rotatable relative to one another;
a second endplate attached either directly or indirectly to the first endplate; and
a compressible core member positioned between the first and second endplates;
wherein rotation of the inner member relative to the outer member causes at least one fixation member to extend outward from the first endplate.
55. The prosthetic intervertebral disc of claim 54 wherein the core member comprises at least one polymeric elastomer.
56. The prosthetic intervertebral disc of claim 54 wherein the at least one fixation member comprises at least one threaded screw.
57. The prosthetic intervertebral disc of claim 56 further comprising at least one opening in one of the inner member or the outer member, the at least one threaded screw being configured to travel within the at least one opening.
58. The prosthetic intervertebral disc of claim 57 wherein the at least one opening is formed in the inner member of the first endplate.
59. The prosthetic intervertebral disc of claim 54 wherein the outer member of the first endplate includes a threaded hole engaged to the threads of the at least one threaded screw to facilitate extension of the at least one threaded screw outward from the first endplate.
60. The prosthetic intervertebral disc of claim 54 further comprising a plurality of fixation members extending outward from the first endplate.
61. The prosthetic intervertebral disc of claim 54 further comprising a plurality of fixation members extending outward from the second endplate.
62. A prosthetic intervertebral disc comprising:
a first endplate having an outer surface with an outer surface area for engaging a first vertebra;
a second endplate attached either directly or indirectly to the first endplate and having an outer surface with an outer surface area for engaging a second vertebra; and
a core member positioned between the first and second endplates;
wherein the first endplate includes a central portion and a first dropleaf side portion, the first dropleaf side portion having a first position relative to the central portion, and a different second position relative to the central portion, in which second position, the first dropleaf side portion increases the outer surface area of the first endplate for engaging a first vertebra.
63. The prosthetic intervertebral disc of claim 62 wherein the core member is compressible.
64. The prosthetic intervertebral disc of claim 62 wherein the core member comprises at least one compressible polymer.
65. The prosthetic intervertebral disc of claim 62 further comprising a hinge attaching the first endplate's first dropleaf side portion to the first endplate's central portion.
66. The prosthetic intervertebral disc of claim 65 wherein the first endplate has a second dropleaf side portion attached to the central portion, the second dropleaf side portion having a first position relative to the central portion and a different second position relative to the central portion, in which second position, the first dropleaf side portion increases the outer surface area of the first endplate for engaging the first vertebra.
67. The prosthetic intervertebral disc of claim 66 further comprising a hinge attaching the first endplate's second dropleaf side portion to the first endplate's central portion.
68. The prosthetic intervertebral disc of claim 62 wherein the second endplate includes a central portion and a first dropleaf side portion, the first dropleaf side portion having a first position relative to the central portion and a different second position relative to the central portion, in which second position, the first dropleaf side portion increases the outer surface area of the second endplate for engaging the second vertebra.
69. The prosthetic intervertebral disc of claim 68 further comprising a hinge attaching the second endplate's first dropleaf side portion to the second endplate's central portion.
70. The prosthetic intervertebral disc of claim 68 wherein the second endplate has a second dropleaf side portion attached to the central portion, the second dropleaf side portion having a first position relative to the central portion, and having a different second position relative to the central portion, in which second position, the first dropleaf side portion increases the outer surface area of the second endplate for engaging the second vertebra.
71. The prosthetic intervertebral disc of claim 70 further comprising a hinge attaching the second endplate's second dropleaf side portion to the second endplate's central portion.
72. The prosthetic intervertebral disc of claim 70 further comprising a spring extending between and attached to the first dropleaf side portions of each of the first endplate and the second endplate.
73. The prosthetic intervertebral disc of claim 72 wherein the first dropleaf side portions of the first endplate and the second endplate each further comprise a slot formed therein, each of the slots engageable with the spring.
74. A prosthetic intervertebral disc assembly comprising: a first endplate; a second endplate attached either directly or indirectly to said first endplate; at least one compressible core member positioned between said first and second endplates; at least one fixation member extending outwardly from at least one of the first and second end plates, wherein the end plates are selected from the group consisting of: pairs of end plates latchable to each other; end plates adapted for use with an installation guidewire; upper and lower end plates including, respectively, one or more downwardly extending extensions and one or more upwardly extending extensions acting as facet replacements; and multiple pairs of endplates suitable for use together in an interspinous space as adjacent multiple prosthetic discs.
75. The prosthetic intervertebral disc of claim 36 wherein the second endplate comprises at least one fixation member moveable from an undeployed state to a deployed state relative to the second endplate, the at least one fixation member being engageable with a vertebral surface when deployed.
76. The prosthetic intervertebral disc of claim 75 wherein the second endplate's at least one fixation member comprises at least one keel slidably engageable with the second endplate.
77. The prosthetic intervertebral disc of claim 75 wherein the second endplate's at least one fixation member in its deployed state extends outward from an outer surface of the first endplate.