Intervertebral stabilizer, methods of use, and instrumentation therefor

• US 20060200241A1
• Filed: 07/07/2005
• Published: 09/07/2006
• Est. Priority Date: 03/03/2005
• Status: Active Grant

• Current Assignee: Cardo Medical LLC (BioCardia, Inc)
• Original Assignee: Accin Corp.
• Inventors: Zubok, Rafail, Rothman, Richard H., Kvitnitsky, Mikhail
• Granted Patent: US 7,582,114 B2
• Time in Patent Office: Days
• US Class Current: 623/17.130
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• 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 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/3013 figure-"8"- or hourglass-shaped
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30327 differing in diameter
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30429 made by inserting a hook into a cooperating slot
• CPC Class Codes: A61F 2002/30566 Helical springs
• CPC Class Codes: A61F 2002/30578 having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30594 slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30795 Blind bores, e.g. of circular cross-section
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30878 with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• 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 2002/4619 : for extraction
• 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 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/001 : Figure-8-shaped, e.g. hourglass-shaped
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0039 : differing in diameter

Abstract

An intervertebral stabilizer includes: a first surface operable to engage an endplate of a first vertebral bone of a spine; a second surface spaced apart from the first surface and operable to engage an endplate of an adjacent second vertebral bone of the spine; a spring element between the first and second surfaces and operable to provide reactive force in response to compression loads from the first and second vertebral bones, wherein a cross-sectional profile taken through the surfaces is hourglass shaped.

Claims

1. An intervertebral stabilizer, comprising:

a first surface operable to engage an endplate of a first vertebral bone of a spine;

a second surface spaced apart from the first surface and operable to engage an endplate of an adjacent second vertebral bone of the spine;

a spring element between the first and second surfaces and operable to provide reactive force in response to compression loads from the first and second vertebral bones, wherein a cross-sectional profile of the spring element taken through the surfaces is hourglass shaped; and

at least a pair of apertures operable to receive an insertion tool for implanting the stabilizer into a patient,

wherein a longitudinal axis of the stabilizer is normal to the first and second surfaces and the apertures extend transverse to the longitudinal axis.

2. The intervertebral stabilizer of claim 1, wherein:

the spring element is formed from a hollow body having at least one slit forming a plurality of annular circumferential helical coils; and

the at least one pair of apertures extend at least partially into the hollow body.

3. The intervertebral stabilizer of claim 2, wherein the at least one pair of apertures are disposed on an anteriorly directed side of the hollow body.

4. The intervertebral stabilizer of claim 2, wherein the first and second apertures are longitudinally positioned such that they are entirely within the hollow body and define a closed interior surface.

5. The intervertebral stabilizer of claim 2, wherein the at least one pair of apertures are longitudinally spaced apart such that a first aperture of the pair is disposed toward the first surface and a second aperture of the pair is disposed toward the second surface.

6. The intervertebral stabilizer of claim 5, wherein one end of the slit terminates at the first aperture of the pair and an opposite end of the slit terminates at the second aperture.

7. An intervertebral trial, comprising:

a handle;

at least one spacer element depending from the handle and being sized and shaped to fit in an intervertebral space between respective endplates of a pair of adjacent vertebral bones, the spacer element including a first surface for engaging one of the endplates and a second surface for engaging the other of the endplates; and

respective roughening elements disposed on the first and second surfaces such that insertion of the spacer element into the intervertebral space simultaneously abrades both endplates in preparation for implantation of an intervertebral device.

8. The intervertebral trial of claim 7, wherein at least one of the roughening elements are formed from substantially sharp knurling disposed on the at least one of the first and second surfaces of the spacer element.

9. An insertion tool for implantation of an intervertebral stabilizer, the intervertebral stabilizer including first and second spaced apart surfaces operable to engage respective endplates of adjacent vertebral bones of a spine, a spring element between the first and second surfaces, and at least a pair of apertures, the insertion tool comprising:

a handle; and

a head having at least a pair of spaced apart pins operable to releaseably engage the at least one pair of apertures.

10. The insertion tool of claim 9, wherein:

a longitudinal axis of the stabilizer is parallel with an longitudinal axis of the intervertebral space and normal to the first and second surfaces; and

the apertures extend transverse to the longitudinal axis of the stabilizer.

11. The insertion tool of claim 10, wherein the pins are flexible in a direction parallel to the longitudinal axis of the stabilizer.

12. The insertion tool of claim 11, wherein the pins are spaced apart at a distance such that the apertures urge the pins apart when the head engages the stabilizer.

13. The insertion tool of claim 12, wherein the pins are spaced apart at the distance such that the first and second surfaces of the stabilizer are urged towards one another when the head engages the stabilizer.

14. The insertion tool of claim 10, wherein a height of the head in a direction parallel to the longitudinal axis of the stabilizer is less than a height between the first and second surfaces of the stabilizer.

15. The insertion tool of claim 14, wherein:

a cross-sectional profile of the spring element taken through the first and second surfaces of the stabilizer is hourglass shaped; and

the height of the head is such that the head at least partially enters into a depression defined by the hourglass shape.

16. The insertion tool of claim 10, wherein the head flairs out in a direction substantially perpendicular to the longitudinal axis of the stabilizer and terminates at respective prongs that provide lateral engagement with the stabilizer at the spring element when the head engages the stabilizer.

17. An insertion tool for implantation of an intervertebral stabilizer, the intervertebral stabilizer including first and second spaced apart surfaces operable to engage respective endplates of adjacent vertebral bones of a spine, and a spring element between the first and second surfaces, the insertion tool comprising:

a first elongate ramp having a proximal end and a distal end, the distal end being sized and shaped for insertion into the intervertebral space and to engage one of the endplates; and

a second elongate ramp having a proximal end and a distal end, the distal end being sized and shaped for insertion into the intervertebral space and to engage the other of the endplates, wherein;

the first and second ramps define upper and lower surfaces, when the distal ends thereof are inserted into the intervertebral space, against which the respective first and second surfaces of the stabilizer may slide; and

at least fixing positions of the proximal ends of the ramps causes at least opening of the intervertebral space as the stabilizer is urged toward the intervertebral space.

18. The insertion tool of claim 17, wherein sliding the stabilizer toward the intervertebral space between the upper and lower surfaces of the ramps causes simultaneous compression of the stabilizer and opening of the intervertebral space.

19. The insertion tool of claim 17, wherein at least one of the first and second ramps includes a stop opposite to the upper or lower surface that is operable to engage the associated intervertebral bone and limit a distance that the distal end thereof may enter into the intervertebral space.

20. The insertion tool of claim 17, further comprising a clamp member operable to fix the positions of the proximal ends of the ramps.

21. The insertion tool of claim 17, wherein respective lateral edges of at least one of the first and second ramps are operable to engage respective guides on at least one of the first and second surfaces of the stabilizer such that the stabilizer is urged to remain between the ramps and engaged against the upper and lower surfaces when sliding towards the intervertebral space.

22. The insertion tool of claim 21, wherein the lateral edges are chamfered.

23. An extraction tool for removing or repositioning an intervertebral stabilizer, the intervertebral stabilizer including first and second spaced apart surfaces operable to engage respective endplates of adjacent vertebral bones of a spine, a spring element between the first and second surfaces, and at least one aperture, the insertion tool comprising:

a handle having proximal and distal ends; and

an engagement element at the proximal end of the handle operable to releasably engage the at least one aperture of the stabilizer such that the stabilizer may be pulled by the handle into a new position or removed from the intervertebral space.

24. The extraction tool of claim 23, wherein:

the spring element is formed from a substantially solid hollow body having at least one slit forming a plurality of annular circumferential helical coils;

the at least one aperture is positioned at a terminal end of the slit and extends through the hollow body; and

the engagement element includes a longitudinally extending member and a transversely extending member, each sized such that the longitudinally extending member may pass through the aperture and the transversely extending member may pass through the slit.

25. The extraction tool of claim 24, wherein the longitudinally extending member is sized such that the transversely extending member may enter the hollow portion of the body of the stabilizer.

26. The extraction tool of claim 25, wherein rotation of the handle results in engagement of the transversely extending member against an interior surface of the hollow body such that the stabilizer may be pulled by the handle.

27. The extraction tool of claim 23, wherein:

the at least one aperture is threaded; and

the engagement element includes a threaded shaft that is threadable into the threaded aperture such that the stabilizer may be pulled by the handle.