METHOD AND APPARATUS FOR SPINAL FACET JOINT FUSION USING IRREGULARLY SHAPED CORTICAL BONE IMPLANTS

• US 20090131986A1
• Filed: 11/19/2008
• Published: 05/21/2009
• Est. Priority Date: 11/19/2007
• Status: Active Grant

• Current Assignee: Innovative Spinal Design LLC
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: LEE, David, Payne, James JR.
• Granted Patent: US 8,961,571 B2
• Time in Patent Office: Days
• US Class Current: 606/247
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/7064 Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor
• CPC Class Codes: A61B 17/846 Nails or pins, i.e. anchors without movable parts, holding by friction only, with or without structured surface A61B17/72, A61B17/86 take precedence
• CPC Class Codes: A61B 17/90 Guides therefor
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/4405 for apophyseal or facet joints, i.e. between adjacent spinous or transverse processes devices implanted between spinous or transverse processes A61B17/7062
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/4601 for introducing bone substitute, for implanting bone graft implants or for compacting them in the bone cavity
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/3013 figure-"8"- or hourglass-shaped
• CPC Class Codes: A61F 2002/30171 rosette- or star-shaped
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/30571 Leaf springs
• CPC Class Codes: A61F 2002/30576 with extending fixation tabs
• CPC Class Codes: A61F 2002/30601 telescopic
• CPC Class Codes: A61F 2002/30617 Visible markings for adjusting, locating or measuring
• CPC Class Codes: A61F 2002/30881 Circumferential ribs, flanges or fins
• CPC Class Codes: A61F 2002/30883 : dovetail-shaped
• 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 2002/4668 : for measuring angles
• CPC Class Codes: A61F 2002/4681 : by applying mechanical shocks, e.g. by hammering
• CPC Class Codes: A61F 2002/4687 : Mechanical guides for implantation instruments
• CPC Class Codes: A61F 2230/0004 : Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/001 : Figure-8-shaped, e.g. hourglass-shaped
• CPC Class Codes: A61F 2230/0028 : Shapes in the form of latin or greek characters
• CPC Class Codes: A61F 2230/005 : Rosette-shaped, e.g. star-shaped
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2250/0097 : Visible markings, e.g. indicia
• CPC Class Codes: A61F 2310/00359 : Bone or bony tissue

Abstract

A method and apparatus for spinal fusion at the facet joint using an irregularly shaped implant where the orientation of the implant can be preselected before implantation.

Claims

1. A facet joint fusion implant comprising:

(a) a substantially solid body having a longitudinal axis;

(b) a plurality of radially extending arms, the arms being circumferentially spaced around the longitudinal axis; and

(c) the body being formed from a material selected from the group consisting of synthetic cortical bone, a harvested synthetic cortical and compacted iliac crest graft and a cadaveric allograft.

2. The facet joint fusion implant of claim 1, wherein there are four arms.

3. The facet joint fusion implant of claim 2, wherein the four arms form a generally “

x”

shape.

4. The facet joint fusion implant of claim 1, wherein the arms include tips which are generally rounded.

5. The facet joint fusion implant of claim 4, wherein between each pair of arms is a valley which valley is rounded.

6. The facet joint fusion implant of claim 1, wherein the body is formed from synthetic cortical bone.

7. The facet joint fusion implant of claim 1, wherein the body is formed from a harvested and compacted iliac crest graft.

8. The facet joint fusion implant of claim 1, wherein the body is formed from a cadaveric allograft.

9. A plug mounted in a hole between bones forming a facet joint, the plug comprising:

(a) a substantially solid body having a longitudinal axis;

(b) a plurality of radially extending, circumferentially spaced arms, each extending radially from around the longitudinal axis; and

(c) the body being formed from a material selected from the group consisting of synthetic cortical bone, a harvested synthetic cortical and compacted iliac crest graft and a cadaveric allograft.

10. The plug mounted in a hole between bones forming a facet joint of claim 9, wherein there are four arms.

11. The plug mounted in a hole between bones forming a facet joint of claim 10, wherein the four arms form generally an “

x”

shape.

12. The plug mounted in a hole between bones forming a facet joint of claim 9, wherein the arms include tips which are rounded.

13. The plug mounted in a hole between bones forming a facet joint of claim 12, wherein between each pair of arms is a valley which valley is rounded.

14. The plug mounted in a hole between bones forming a facet joint of claim 9, formed from a synthetic cortical bone.

15. The plug mounted in a hole between bones forming a facet joint of claim 9, formed from a harvested and compacted iliac crest graft.

16. The plug mounted in a hole between bones forming a facet joint of claim 9, formed from an iliac cadaveric allograft.

17. A method of mounting an implant in a facet joint C1-C2 and L5-S1, the method comprising the steps of:

(a) cutting an arthroscopic type portal in the tissue of a patient outside a diseased or damaged facet joint;

(b) using a positioning selection tool to select an orientation of a plug to be implanted, the selected orientation including a plurality of prongs defining an orientation the plug to be implanted;

(c) placing an implantation guide in operative connection with the positioning selection tool;

(d) while maintaining at least two distinct prongs of the selected orientation removing the positioning selection tool from operative connection with the implantation guide;

(e) placing a cutting tool in operative connection with the implantation guide, and using operative connection between the cutting tool and implantation guide to form a shaped hole between two opposed bones forming the facet joint, the shaped hole having at least the two distinct prongs of orientation specified in step “

d”

; and

(f) inserting a preshaped plug into the hole, the plug having a shape substantially the same as the hole.

18. The method of claim 17, wherein in step “

f”

the plug comprises;

(i) a substantially solid body having a longitudinal axis;

(ii) a plurality of opposed arms, the arms being symmetrically disposed around the longitudinal axis; and

(iii) the body being formed from a material selected from the group consisting of synthetic cortical bone, a harvested synthetic cortical and compacted iliac crest graft and a cadaveric allograft.

19. The method of claim 17, wherein there are four arms.

20. The method of claim 19, wherein the four arms form an “

X”

.

21. The method of claim 17, wherein the arms include tips which are rounded.

22. The method of claim 21, wherein between each pair of arms is a valley which valley is rounded.

23. The method of claim 17, wherein the body is formed from synthetic cortical bone.

24. The method of claim 17, wherein the body is formed from a harvested and compacted iliac crest graft.

25. The method of claim 17, wherein the body is formed from a cadaveric allograft.

26. A method of fusing a patient'"'"'s facet joint comprising the steps of:

(a) forming a surgically cut opening in the patient'"'"'s spine next to the facet joint, the opening including a plurality of radially extending, circumferentially spaced apart slots;

(b) providing an implant that has a body with a plurality of radially extending and circumferentially spaced apart arms, each arm being sized and shaped to occupy a slot of the surgically formed opening;

(c) placing the implant in the surgically formed opening; and

(d) wherein step “

a”

through “

c”

include placing at least one arm into a slot formed on two adjacent vertebrae of the patient'"'"'s spine.

27. The method of claim 26 wherein step “

a”

employs a cutting tool that is driven with hammer blows.

28. The method of claim 26 wherein in step “

a”

an instrument is employed that has a pair of prongs used to engage two adjacent vertebrae of the patient'"'"'s spine.

29. The method of claim 26 wherein in step “

b”

the implant has four arms.

30. The method of claim 29 wherein in step “

d”

two arms are placed into slots on one vertebrae of the patient'"'"'s spine and two arms are placed into slots on the other patient'"'"'s spine.

31. The method of claim 26 wherein the implant of step “

a”

is harvested bone.

32. The method of claim 26 wherein the implant of step “

a”

is an allograft.

33. The method of claim 26 wherein the implant of step “

a”

is a bone graft material.

34. The method of claim 26 wherein step “

b”

further comprises providing the implant with an alternating plurality of arms and plurality of valleys between arms.

35. The method of claim 26 wherein in step “

a”

an instrument removes bone that is cut to form the opening.

36. The method of claim 26 wherein in step “

c”

an instrument places the implant.