EXPANDABLE INTERVERTEBRAL IMPLANT

• US 20110035011A1
• Filed: 04/03/2009
• Published: 02/10/2011
• Est. Priority Date: 04/05/2008
• Status: Active Grant

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Cain, Christopher Marden John
• Granted Patent: US 8,936,641 B2
• Time in Patent Office: Days
• US Class Current: 623/17.16
• 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 2/4425 made of articulated components
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2/4611 of spinal 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 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30462 retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2002/30471 connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2002/30495 using a locking ring
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/3052 unrestrained in only one direction, e.g. moving unidirectionally
• CPC Class Codes: A61F 2002/30537 adjustable
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/4415 elements of the prosthesis being arranged in a chain like manner
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2002/4485 : comprising three or more adjacent spinal implants
• CPC Class Codes: A61F 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2002/4628 : with linear motion along or rotating motion about an axis transverse to the instrument axis or to the implantation direction, e.g. clamping
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• 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 2220/0091 : connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

An expandable intervertebral implant (20) is provided for insertion into an intervertebral space defined by adjacent vertebrae. The expandable intervertebral implant includes a pair of outer sleeve portions (30A, 30B) and an inner core (50) disposed between the outer sleeve portions. Movement of the inner core relative to the outer sleeve portions causes the outers sleeve portions to deflect away from each other, thereby engaging the expandable intervertebral implant with the vertebrae and adjusting the height of the intervertebral space.

Claims

1. An expandable intervertebral implant insertable into an intervertebral disc space and expandable from an initial position to an expanded position, the expandable intervertebral implant comprising:

a linkage that includes a plurality of links connected in a longitudinal direction, each link comprising;

an outer sleeve including a first outer sleeve portion and a second outer sleeve portion that is movable with respect to the first outer sleeve portion, wherein the second outer sleeve portion defines a first engagement surface that is sloped with respect to the longitudinal direction;

an inner core disposed between the first and second outer sleeve portions, the inner core defining a second engagement surface that is sloped with respect to the longitudinal direction and abuts the first engagement surface;

wherein relative movement between the inner core and the second outer sleeve portion along the longitudinal direction causes the first engagement surface to ride along the second engagement surface, thereby causing the second outer sleeve portion to deflect away from the first outer sleeve portion in a direction substantially perpendicular to the longitudinal direction.

2. The expandable intervertebral implant as recited in claim 1, wherein the outer sleeve and inner core define engagement members that interlock after the outer sleeve portions have expanded to the expanded position, thereby preventing the outer sleeve portions from contracting toward each other.

3. The expandable intervertebral implant as recited in claim 2, wherein the engagement members comprise a plurality of projections extending toward each other from the first and second engagement surfaces, wherein the projections cam over each other as so as to cause the second outer sleeve portion to incrementally deflect away from the first outer sleeve portion.

4. The expandable intervertebral implant as recited in claim 3, wherein the projections comprise reverse angled teeth.

5. The expandable intervertebral implant as recited in claim 1, wherein the first and second engagement portions form a vertical angle with respect to the longitudinal direction, such that the second outer sleeve portion expands vertically with respect to the first outer sleeve portion.

6. The expandable intervertebral implant as recited in claim 1, wherein the second outer sleeve portion defines a third engagement surface and the inner core defines a fourth engagement surface that abuts the third engagement surface, and the third and fourth engagement surfaces define a lateral angle with respect to the horizontal direction, such that relative movement between the inner core and the outer sleeve portions causes the second outer sleeve portion to expand laterally with respect to the first outer sleeve portion.

7. The expandable intervertebral implant as recited in claim 1, wherein the first engagement surface of the second outer sleeve portion of one of the links is sloped at a first angle with respect to the longitudinal direction, and the first engagement surface of the second outer sleeve portion of another one of the links is sloped at a second angle with respect to the longitudinal direction, and the first angle is different than the second angle.

8. The expandable intervertebral implant as recited in claim 7, wherein the links each define opposing vertebral engagement surfaces that extend at an angle relative to the longitudinal direction, and the angle of the vertebral engagement surfaces of each link is different than the angle of the vertebral engagement surfaces of the other links.

9. The expandable intervertebral implant as recited in claim 7, wherein the links each define opposing vertebral engagement surfaces are sloped with respect to the longitudinal direction, and the vertebral engagement surfaces of each link are aligned with and extend parallel with each other.

10. The expandable intervertebral implant as recited in claim 1, further comprising a biasing member that engages the inner core member, and a brace member that engages the outer sleeve portions, such that the biasing member is movable with respect to the brace member so as to move the inner core member relative to the outer sleeve portions.

11. The expandable intervertebral implant as recited in claim 1, wherein adjacent ones of the plurality of links are joined at a coupling location, and expandable intervertebral implant further comprises a retainer band placed at the coupling location so as to apply a compressive retaining force to the joined links.

12. The expandable intervertebral implant as recited in claim 1, wherein the first outer sleeve portion defines a third engagement surface, and the inner core member defines a fourth engagement surface that abuts the third engagement surface, such that relative movement between the inner core and the first outer sleeve portion along the longitudinal direction causes the third engagement surface to ride along the fourth engagement surface, thereby causing the first outer sleeve portion to deflect away from the second outer sleeve portion.

13. The expandable intervertebral implant as recited in claim 12, wherein the first and second engagement surfaces are parallel to each other, and the third and fourth engagement surfaces are parallel to each other.

14. The expandable intervertebral implant as recited in claim 1, wherein the links are integrally and rigidly connected to each other.

16. The expandable intervertebral implant as recited in claim 1, wherein the engagement surfaces of the outer sleeve comprise engagement members, the engagement surfaces of the inner core further comprise engagement members, and the engagement members of the outer sleeve mate with the engagement members of the inner core so as to prevent the first and second outer sleeve portions from contracting toward each other.

17. The expandable intervertebral implant as recited in claim 16, wherein the engagement members comprise longitudinally spaced teeth projecting from the engagement surfaces.

18. The expandable intervertebral implant as recited in claim 17, wherein the interlocking teeth are reverse angle teeth.

15. An expandable intervertebral implant for insertion into an intervertebral disc space and expandable from an initial position to an expanded position, the expandable intervertebral implant comprising:

an outer sleeve extending along a longitudinal direction, the outer sleeve including a first outer sleeve portion and a second outer sleeve portion that is movable with respect to the first outer sleeve portion in a transverse direction that is substantially perpendicular to the longitudinal direction, wherein the first and second outer sleeve portions each define an engagement surface that is sloped with respect to the longitudinal direction; and

an inner core disposed between the outer sleeve portions, the inner core defining a pair of engagement surfaces that mate with the engagement surfaces of the first and second outer sleeve portions, respectively, such that relative movement between the inner core and the outer sleeve along the longitudinal direction causes the first and second outer sleeve portions to deflect away from each other along the engagement surfaces of the inner core.

19. The expandable intervertebral implant as recited in claim 15, further comprising a biasing member extending through the inner core and connected to the inner core, and a brace that engages the outer sleeve, wherein the biasing member applies a longitudinally directed force to the inner core that causes the inner core to move longitudinally with respect to the outer sleeve.

20. An expandable intervertebral implant kit comprising:

an outer sleeve member extending along a longitudinal direction and defining an outer vertebral engagement surface and an inner engagement surface disposed vertically opposite the vertebral engagement surface, the inner engagement surface being sloped with respect to the longitudinal direction, wherein the outer sleeve member is disposed at a first vertical position;

an inner core presenting an engagement surface sloped with respect to the longitudinal direction, wherein the engagement surface of the inner core mates with the inner engagement surface of the outer sleeve member, such that relative movement of the inner core with respect to the outer sleeve member causes the outer sleeve member to ride along the engagement surface of the inner core and deflect to a second vertical position that is different than the first vertical position.