Spinal implants and methods of providing dynamic stability to the spine

• US 20070050028A1
• Filed: 04/05/2006
• Published: 03/01/2007
• Est. Priority Date: 08/26/2005
• Status: Abandoned Application

• Current Assignee: Magellan Spine Technologies, Inc.
• Original Assignee: Magellan Spine Technologies, Inc.
• Inventors: Conner, E.
• Application Number:
  US11/398,434
• Publication Number:
  US 20070050028A1
• Time in Patent Office: Days
• US Class Current: 623/17.110
• 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

The present application discloses a plurality of spinal implants and methods for repairing annular defects in intervertebral discs and for providing dynamic stability to the motion segment of the spine in the vicinity of the repaired disc. Each of the implants comprises a head portion and a tail portion. In the illustrated embodiments, the head portion of each implant is enlarged relative to the tail portion. Each of the head portions and tail portions is adapted to support adjacent vertebrae and resist collapse of the intervertebral disc. A tapered portion of each implant engages end plates of the adjacent vertebrae to resist forces tending to push the implant out of the intervertebral space. The tail portion of each implant 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 be implanted in an intervertebral disc located between a first vertebral disc and a second vertebral disc to repair an annular defect in the intervertebral disc, and to provide dynamic stability to a motion segment of a spine in the vicinity of the intervertebral disc, 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 at least a portion of its length from a greater height to a lesser height away from the first head segment; and

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.

2. The spinal implant of claim 1, wherein the first tail segment has a constant height along its length.

3. The spinal implant of claim 1, wherein upon permanent implantation within the intervertebral disc the head portion abuts and supports facing endplates of the first and second vertebral discs to aid in preventing collapse of the intervertebral disc while providing dynamic stability to the motion segment, and the tail portion abuts and supports the facing endplates to further aid in preventing collapse of the intervertebral disc while providing dynamic stability to the motion segment, and also abuts extradiscal lips of the first and second vertebral discs to thereby prevent the implant from penetrating the intervertebral disc beyond a desired amount.

4. The spinal implant of claim 1, wherein the head portion further includes at least a third head segment that extends from the first head segment opposite the second head segment.

5. The spinal implant of claim 4, wherein the third head segment tapers along at least a portion of its length from a greater height to a lesser height away from the first head segment.

6. The spinal implant of claim 1, wherein cross-sections of the implant taken along the longitudinal axis thereof are circular, oval, elliptical or rectilinear.

7. The spinal implant of claim 1, wherein the implant is constructed of one or more of bone, polymers or metals.

8. A spinal implant adapted to be implanted in an intervertebral disc located between a first vertebral disc and a second vertebral disc to repair an annular defect in the intervertebral disc, and to provide dynamic stability to a motion segment of a spine in the vicinity of the intervertebral disc, 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 tapering along at least a portion of its length from a greater height to a lesser height away from the second head segment, 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; and

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 first tail segment having a constant height along its length, 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.

9. The spinal implant of claim 8, wherein the tapered portion of the first head segment tapers at a constant rate.

10. The spinal implant of claim 8, wherein the tapered portion of the second head segment tapers at a rate that increases away from the first head segment.

11. The spinal implant of claim 8, wherein the head portion further includes at least a third head segment having a length greater than zero that is interposed between the first head segment and the second head segment.

12. The spinal implant of claim 11, wherein the third head segment has a constant height along its length.

13. A method of repairing an annular defect in an intervertebral disc located between a first vertebral disc and a second vertebral disc, and providing dynamic stability to a motion segment of a spine in the vicinity of the intervertebral disc, the method comprising the steps of:

removing at least a portion of the intervertebral disc;

preparing an implantation site in the vicinity of the intervertebral disc; and

implanting a spinal implant device at the implantation site;

wherein the step of preparing the implantation site includes the steps of;

reaming the implantation site to remove bone material from endplates of each of the first and second vertebral discs and thereby shape a portion of each of the endplates to receive the implant device in a substantially complementary fit; and

countersinking the implantation site to remove bone material from extradiscal lips of each of the first and second vertebral discs and thereby shape a portion of each of the extradiscal lips to receive the implant device in a substantially complementary fit.

14. The method of claim 13, further comprising the step of measuring a distance between the endplates to determine an appropriate size for the implant device.

15. A method of repairing an annular defect in an intervertebral disc located between a first vertebral disc and a second vertebral disc, and providing dynamic stability to a motion segment of a spine in the vicinity of the intervertebral disc, the method comprising the steps of:

removing at least a portion of the intervertebral disc;

preparing an implantation site in the vicinity of the intervertebral disc; and

implanting a spinal implant device at the implantation site;

wherein the implant comprises 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 at least a portion of its length from a greater height to a lesser height away from the first head segment, and 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 first tail segment having a constant height along its length, 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.