Artificial disc implant

• US 6,881,228 B2
• Filed: 02/28/2002
• Issued: 04/19/2005
• Est. Priority Date: 06/04/1999
• Status: Expired due to Term

• Current Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: McKay, William F., Zdeblick, Thomas A.
• Primary Examiner(s): BARRETT, THOMAS C
• Application Number:
  US10/085,872
• Publication Number:
  US 20020082701A1
• Time in Patent Office: 1,146 Days
• Field of Search: 623/17.15, 623/17.16, 623/17.11
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/30742 Bellows or hose-like seals; Sealing membranes A61B17/8808 takes precedence; sealing membranes for retaining bone substitute A61F2/2846
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• 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 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30121 with lobes
• CPC Class Codes: A61F 2002/30123 with two diametrically opposed lobes
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/30228 Cylinders of elliptical or oval basis
• CPC Class Codes: A61F 2002/3023 wedge-shaped cylinders
• CPC Class Codes: A61F 2002/30237 partial tubes
• CPC Class Codes: A61F 2002/30372 with additional means for limiting said translation
• CPC Class Codes: A61F 2002/3039 with possibility of relative movement of the rib within the groove
• CPC Class Codes: A61F 2002/30563 : having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30578 : having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30808 : parallel
• CPC Class Codes: A61F 2002/30879 : Ribs
• CPC Class Codes: A61F 2002/30892 : parallel
• CPC Class Codes: A61F 2002/30975 : made of two halves
• 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 2210/0014 : using shape memory or superelastic materials, e.g. nitinol
• 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 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00976 : Coating or prosthesis-covering structure made of proteins or of polypeptides, e.g. of bone morphogenic proteins BMP or of transforming growth factors TGF

Abstract

An artificial disc implant includes an upper shell, a lower shell, and a spacer therebetween. The spacer preferably has properties similar to that of a natural spinal disc, while the upper and lower shells form a rigid interface between the implant and the adjacent vertebral bodies. The upper and lower shells can be configured to prevent expulsion of the spacer from the disc space. The implant upper and lower shells may further be configured into partially cylindrical shapes for ease of insertion through an insertion tube as presently known for interbody fusion devices. The devices may further be configured for insertion through a double-barreled insertion tube. Methods and instruments for inserting an artificial disc implant are also provided.

Claims

1. A method for inserting an artificial disc implant into a spinal disc space, comprising:

accessing the disc space;

preparing an implant insertion location in the disc space;

providing an implant having an upper shell, a lower shell, and an elastic spacer between the upper shell and the lower shell, the elastic spacer having a dehydratable hydrogel core;

dehydrating the hydrogel core to reduce the spacer height between the upper and lower shells;

inserting the implant into the disc space; and

rehydrating the hydrogel core to expand the spacer in the disc space and position the upper and lower shells in rigid engagement with an adjacent vertebral endplate.

2. The method of claim 1, further comprising:

inserting a sleeve adjacent the disc space, the sleeve having a working channel extending between a proximal end and a distal end; and

inserting the implant includes inserting the implant through the working channel of the sleeve.

3. The method of claim 2, wherein the sleeve is a double barrel sleeve having a pair of adjacent working channels.

4. The method of claim 3, wherein providing an implant includes providing the implant with the upper shell and the lower shell, each shell including a pair of partially cylindrical lobes interconnected by an intermediate portion, the implant being configured for insertion through the adjacent working channels of the double barrel sleeve.

5. The method of claim 1, wherein said upper and lower shells are separate from one another.

6. The method of claim 1, wherein said upper and lower shells are rigid.

7. A method for inserting an artificial disc implant into a spinal disc space, comprising:

accessing the disc space;

inserting a sleeve adjacent the disc space, the sleeve having a working channel extending between a proximal end and a distal end;

preparing an implant insertion location in the disc space through the sleeve;

providing an implant having an upper shell, a lower shell, and a spacer between the upper shell and the lower shell, wherein said upper and lower shells are separate from one another;

reducing the height of the implant between the upper and lower shells;

inserting the reduced height implant through the working channel of the sleeve to the implant insertion location in the disc space; and

expanding the reduced height implant in the disc space so that the upper shell and the lower shell rigidly engage adjacent vertebral endplates.

8. The method of claim 7, wherein providing an implant includes providing the implant with a substantially cylindrical shape.

9. The method of claim 8, wherein:

accessing the disc space includes accessing the disc space from a posterior approach; and

the sleeve includes a cylindrical working channel.

10. The method of claim 9, further comprising:

accessing the disc space at a second location;

inserting a sleeve adjacent the disc space at the second location, the sleeve having a cylindrical working channel extending between a proximal end and a distal end;

preparing a second implant insertion location in the disc space through the sleeve;

providing a second implant having an upper shell, a lower shell, and a spacer between the upper shell and the lower shell;

reducing the height of the second implant between the upper and lower shells; and

inserting the reduced height second implant through the working channel of the sleeve to the second implant insertion location in the disc space.

11. The method of claim 7, wherein the sleeve is a double barrel sleeve having a pair of adjacent working channels.

12. The method of claim 11, wherein providing an implant includes providing the implant with the upper shell and the lower shell, each shell including a pair of partially cylindrical lobes interconnected by an intermediate portion, the implant being configured for insertion through the adjacent working channels of the double barrel sleeve.

13. The method of claim 11, wherein reducing the height of the implant includes dehydrating the spacer.

14. The method of claim 7, wherein reducing the height of the implant includes compressing the spacer between the upper shell and the lower shell.

15. The method of claim 14, wherein the spacer is elastic.

16. The method of claim 7, wherein said upper and lower shells are rigid.

17. A method for inserting an artificial disc implant into a spinal disc space, comprising:

accessing the disc space;

preparing an implant insertion location in the disc space;

providing an implant having an upper shell, a lower shell, and a spacer between the upper shell and the lower shell, the spacer having a hydratable hydrogel core;

inserting the implant into the disc space; and

hydrating the hydrogel core to expand the spacer in the disc space and rigidly engage the upper and lower shells with an adjacent vertebral endplate.

18. The method of claim 17, further comprising:

inserting a sleeve adjacent the disc space, the sleeve having a working channel extending between a proximal end and a distal end; and

inserting the implant includes inserting the implant through the working channel of the sleeve.

19. The method of claim 18, wherein the sleeve is a double barrel sleeve having a pair of adjacent working channels.

20. The method of claim 19, wherein providing an implant includes providing the implant with the upper shell and the lower shell, each shell including a pair of partially cylindrical lobes interconnected by an intermediate portion, the implant being configured for insertion through the adjacent working channels of the double barrel sleeve.

21. The method of claim 17, wherein hydrating the hydrogel core includes expanding the spacer in the disc space to position the upper shell and lower shell in contact with an adjacent vertebral endplate.

22. The method of claim 17, further comprising:

dehydrating the hydrogel core to reduce the spacer height between the upper and lower shells before inserting the implant into the disc space; and

rehydrating the hydrogel core to expand the spacer in the disc space after inserting the implant into the disc space.

23. The method of claim 17, wherein accessing the disc space includes accessing the disc space from an anterior approach.

24. The method of claim 17, wherein said upper and lower shells are separate from one another.

25. The method of claim 17, wherein said upper and lower shells are rigid.