Spinal implants and methods of providing dynamic stability to the spine

• US 20080071377A1
• Filed: 03/21/2007
• Published: 03/20/2008
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: Conner E. Scott
• Original Assignee: Magellan Spine Technologies, Inc.
• Inventors: Valko, Jeffrey, Conner, E. Scott
• Granted Patent: US 7,963,991 B2
• Time in Patent Office: Days
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/1615 Drill bits, i.e. rotating tools extending from a handpiece to contact the worked material
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/70 Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
• CPC Class Codes: A61B 2017/00261 Discectomy
• CPC Class Codes: A61B 2090/061 for measuring dimensions, e.g. length
• CPC Class Codes: A61B 2090/062 penetration depth
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/30113 circular
• CPC Class Codes: A61F 2002/30242 spherical
• CPC Class Codes: A61F 2002/30383 made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30462 retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2002/30481 using a locking clip
• CPC Class Codes: A61F 2002/30565 having spring elements
• CPC Class Codes: A61F 2002/30574 with an integral complete or partial collar or flange
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30616 : Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30892 : parallel
• CPC Class Codes: A61F 2002/4435 : Support means or repair of the natural disc wall, i.e. annulus, e.g. using plates, membranes or meshes
• CPC Class Codes: A61F 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• CPC Class Codes: A61F 2002/4677 : using a guide wire
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2220/0075 : sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2230/0004 : Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0071 : spherical
• CPC Class Codes: A61F 2310/00011 : Metals or alloys

Abstract

Spinal implants and methods to repair annular defects in intervertebral discs and provide dynamic stability to the spine in the vicinity of a repaired disc are described. Some implants include head and tail portions. In some embodiments, the head portion of an implant is enlarged relative to the tail portion. Some head portions and tail portions are adapted to support adjacent vertebrae and resist collapse of the intervertebral disc. Head portions provide a spacer function to maintain separation between adjacent vertebrae. A tapered portion of some implants engages end plates of adjacent vertebrae to resist forces tending to push the implant out of the intervertebral space. The tail portion of some implants includes a tail flange (which in some embodiments is of similar diameter to the head portion) that abuts extradiscal lips of the adjacent vertebrae and resists forces tending to push the implant deeper into the intervertebral space.

Claims

1. A spinal implant adapted to repair an annular defect in the annulus fibrosus of an intervertebral disc, located in an intervertebral disc space between adjacent vertebrae of a spine, the implant comprising:

a head portion, comprising a first head segment having a length greater than zero as measured along a longitudinal axis of the implant and having a substantially constant height along its length; and

a tail portion, including a first tail segment and a second tail segment, the first tail segment coupled to the head portion, the second tail segment being configured to prevent substantial extrusion of intervertebral disc material through the annular defect when the head portion is positioned between the adjacent vertebrae and when the second tail segment contacts a surface of the annulus fibrosus and spans a width of the annular defect.

2. The spinal implant of claim 1, wherein the second tail segment is configured to abut at least one of the extradiscal lips of the adjacent vertebrae, and to abut the annulus fibrosus, when the head portion is positioned between the adjacent vertebrae.

3. The spinal implant of claim 1, wherein the second tail segment is configured to contact an outer surface of the annulus fibrosus.

4. The spinal implant of claim 1, wherein the first tail segment is reversibly coupled to the head portion.

5. The spinal implant of claim 1, wherein the first tail segment is lockably coupled to the head portion.

6. The spinal implant of claim 1, wherein the head portion further comprises a second head segment that is adjacent the first head segment and that has a length greater than zero as measured along a longitudinal axis of the implant, the second head segment tapering along at least a portion of its length from a greater height to a lesser height away from the first head segment.

7. A method of providing dynamic stability to the spine in the vicinity of an intervertebral disc, the method comprising the steps of:

removing bone material from at least one of the endplates of either or both of adjacent first and second vertebrae, thereby shaping a portion of the at least one of the adjacent first and second vertebrae to create an implantation site that is sized and shaped to receive a spinal implant in a substantially complementary fit; and

implanting the spinal implant device at the implantation site such that it contacts the first and second vertebrae in the substantially complementary fit.

8. The method of claim 7, further comprising removing bone material from the two facing endplates of the adjacent first and second vertebrae.

9. The method of claim 7, further comprising countersinking the implantation site to remove bone material from each of the first and second vertebrae.

10. A spinal implant adapted to repair an annular defect in the annulus fibrosus of an intervertebral disc, located between adjacent vertebrae of a spine, the implant comprising:

a head portion configured to be placed between the adjacent vertebrae, the head portion comprising a buttress portion that, when positioned between the adjacent vertebrae, spans a distance between, and contacts, the adjacent vertebrae; and

a barrier portion having a width that is greater than a width of the annular defect, the barrier portion being configured to prevent substantial extrusion of intervertebral disc material through the annular defect when the barrier portion is positioned to contact a surface of the annulus fibrosus;

wherein the head portion is coupled to the barrier portion.

11. The spinal implant of claim 10, wherein the surface of the annulus fibrosus is an outer surface.

12. The spinal implant of claim 10, wherein the head portion is reversibly coupled to the barrier portion.

13. The spinal implant of claim 10, wherein the head portion is lockably coupled to the barrier portion.

14. The spinal implant of claim 10, wherein the head portion has a section having a substantially constant height that is approximately equal to the distance between the adjacent vertebrae.

15. The spinal implant of claim 10, wherein upon implantation within the intervertebral disc space between the adjacent vertebrae:

the head portion abuts and supports facing endplates of adjacent vertebrae to aid in preventing at least partial collapse of the intervertebral disc; and

the barrier portion abuts at least one of the extradiscal lips of the adjacent vertebrae, thereby substantially preventing the barrier portion from entering into the intervertebral disc space.

16. The spinal implant of claim 10, wherein a height of the head portion is adapted such that the head portion operates as a spacer to maintain a desired separation distance between the adjacent vertebrae.

17. The spinal implant of claim 10, wherein a cross-section of the implant taken along a longitudinal axis thereof is at least one of circular, oval, elliptical, and rectilinear.

18. The spinal implant of claim 10, wherein the implant comprises at least one of bone, a polymer, and a metal.

19. The spinal implant of claim 10, further comprising a lumen passing therethrough.

20. The spinal implant of claim 19, wherein the lumen is adapted to receive an elongate member.

21. The spinal implant of claim 20, wherein the elongate member comprises a guide wire.

22. The spinal implant of claim 10, further comprising splines that engage opposing surfaces of the adjacent vertebrae.

23. The spinal implant of claim 10, wherein the head portion and the barrier portion are coupled by a flexible tether.

24. The spinal implant of claim 10, further comprising a threaded portion that engages opposing surfaces of the adjacent vertebrae.

25. The spinal implant of claim 10, further comprising barbs that engage opposing surfaces of the adjacent vertebrae.

26. The spinal implant of claim 10, wherein the head portion and barrier portion comprise different materials.

27. A system for use in the repair of an annular defect in the annulus fibrosus of an intervertebral disc, located between adjacent vertebrae of a spine, comprising;

a spinal implant comprising a head portion configured to be placed between the adjacent vertebrae;

a barrier portion having a width that is greater than a width of the annular defect;

an elongate member adapted to pass through a lumen of the spinal implant;

wherein the head portion comprises a buttress portion that, when positioned between the adjacent vertebrae, spans a distance between, and contacts, the adjacent vertebrae;

wherein the barrier portion is configured to prevent substantial extrusion of intervertebral disc material through the annular defect when the barrier portion is positioned to contact a surface of the annulus fibrosus;

wherein the head portion is coupled to the barrier portion;

wherein an elongate member passes through said lumen of said head portion and said barrier portion, wherein the elongate member is adapted to direct the spinal implant toward the annular defect.

28. The system of claim 27, wherein the elongate member comprises a surgical guide wire.

29. The system of claim 27, wherein the head portion is reversibly coupled to the barrier portion.

30. The system of claim 27, wherein the head portion is lockably coupled to the barrier portion.

31. A spinal implant adapted to repair an annular defect in the annulus fibrosus of an intervertebral disc, located between adjacent vertebrae of a spine, the implant comprising:

means for maintaining a separation distance between the adjacent vertebrae; and

means for preventing substantial extrusion of intervertebral disc material through the annular defect when the means for preventing is positioned to contact a surface of the annulus fibrosus and when the means for maintaining is positioned between the adjacent vertebrae;

wherein the means for maintaining is coupled to the means for preventing.

32. A spinal implant adapted to repair an annular defect in the annulus fibrosus of an intervertebral disc, located between adjacent vertebrae of a spine, the implant comprising:

a head portion including at least a first head segment and a second head segment, each of the first and second head segments having a length greater than zero as measured along a longitudinal axis of the implant, the first head segment having a constant height along its length, the second head segment tapering along as least a portion of its length from a greater height to a lesser height away from the first head segment;

a tail portion extending from the head portion and including at least a first tail segment and a second tail segment, the first tail segment adjoining the second head segment, each of the first and second tail segments having a length greater than zero as measured along a longitudinal axis of the implant, the second tail segment tapering along at least a portion of its length from a lesser height to a greater height away from the first tail segment.

33. The implant of claim 32, wherein the head portion is reversibly coupled to the barrier portion.

34. The implant of claim 32, wherein the head portion is lockably coupled to the barrier portion.

35. The implant of claim 32, wherein the second tail segment is configured to contact an outer surface of the annulus fibrosus.

36. The spinal implant of claim 32, wherein upon implantation within the intervertebral disc space between the adjacent vertebrae:

the head portion abuts and supports facing endplates of adjacent vertebrae to aid in preventing at least partial collapse of the intervertebral disc; and

the tail portion abuts at least one of the extradiscal lips of the adjacent vertebrae, thereby substantially preventing the barrier portion from entering into the intervertebral disc space.

37. A spinal implant adapted to repair an annular defect in the annulus fibrosus of an intervertebral disc, located between adjacent vertebrae of a spine, the implant comprising:

a head portion, comprising a first head segment having a length greater than zero as measured along a longitudinal axis of the implant and having a substantially constant height along its length;

a tail portion extending from the head portion and including at least a first tail segment and a second tail segment, the first tail segment adjoining the second head segment, each of the first and second tail segments having a length greater than zero as measured along a longitudinal axis of the implant, the second tail segment tapering along at least a portion of its length from a lesser height to a greater height away from the first tail segment

38. The implant of claim 37, wherein the head portion is reversibly coupled to the barrier portion.

39. The implant of claim 37, wherein the head portion is lockably coupled to the barrier portion.

40. The implant of claim 37, wherein the second tail segment is configured to contact an outer surface of the annulus fibrosus.

41. The spinal implant of claim 37, wherein upon implantation within the intervertebral disc space between the adjacent vertebrae:

the head portion abuts and supports facing endplates of adjacent vertebrae to aid in preventing at least partial collapse of the intervertebral disc; and

the tail portion abuts at least one of the extradiscal lips of the adjacent vertebrae, thereby substantially preventing the barrier portion from entering into the intervertebral disc space.

42. A spinal implant adapted to repair an annular defect in the annulus fibrosus of an intervertebral disc, located between adjacent vertebrae of a spine, the implant comprising:

a head portion including at least a first head segment and a second head segment, each of the first and second head segments having a length greater than zero as measured along a longitudinal axis of the implant, the first head segment having a constant height along its length, the second head segment tapering along as least a portion of its length from a greater height to a lesser height away from the first head segment;

a barrier portion having a width that is greater than a width of the annular defect, the barrier portion being configured to prevent substantial extrusion of intervertebral disc material through the annular defect when the barrier portion is positioned to contact a surface of the annulus fibrosus;

wherein the head portion is coupled to the barrier portion.

43. The implant of claim 42, wherein the head portion is reversibly coupled to the barrier portion.

44. The implant of claim 42, wherein the head portion is lockably couple to the barrier portion.

45. The implant of claim 42, wherein the barrier portion is configured to contact an outer surface of the annulus fibrosus

46. The spinal implant of claim 42, wherein upon implantation within the intervertebral disc space between the adjacent vertebrae:

the head portion abuts and supports facing endplates of adjacent vertebrae to aid in preventing at least partial collapse of the intervertebral disc; and

the barrier portion abuts at least one of the extradiscal lips of the adjacent vertebrae, thereby substantially preventing the barrier portion from entering into the intervertebral disc space.

47. A method of repairing an annular defect in the annulus fibrosus of an intervertebral disc, located between adjacent vertebrae of a spine, the method comprising:

providing a spinal implant, comprising;

a head portion configured to be placed between the adjacent vertebrae, the head portion comprising a buttress portion that, when positioned between the adjacent vertebrae, spans a distance between, and contacts, the adjacent vertebrae; and

a barrier portion having a width that is greater than a width of the annular defect, the barrier portion being configured to prevent substantial extrusion of intervertebral disc material from the intervertebral disc when the barrier portion is positioned to contact a surface of the annulus fibrosus;

wherein the head portion is coupled to the barrier portion; and

positioning the head portion between the adjacent vertebrae.

48. The method of claim 47, wherein the implant further comprises a lumen passing therethrough, and the positioning of the implant comprises moving the implant along an elongate member, which passes through the lumen.

49. The method of claim 47, wherein the elongate member comprises a guide wire.