Frusto-conical spinal implant

• US 7,942,933 B2
• Filed: 04/03/2010
• Issued: 05/17/2011
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: Michelson, Gary Karlin
• Primary Examiner(s): Robert; Eduardo C
• Assistant Examiner(s): Hammond; Ellen C
• Application Number:
  US12/798,364
• Publication Number:
  US 20100217394A1
• Time in Patent Office: 409 Days
• Field of Search: 623/17.11, 623/17.16, 606/246, 606/279
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/32 Surgical cutting instruments A61B18/042 takes precedence; suture cutters A61B17/0467; instruments for ligaturing or cutting A61B17/128; instruments for rupturing the amniotic membrane A61B17/4208; specially adapted knives for eye surgery A61F9/0133
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61B 2017/922 Devices for impaction, impact element
• CPC Class Codes: A61B 2090/036 abutting on tissue or skin
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• 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 2/446 having a circular or elliptical cross-section substantially parallel to the axis of the spine, e.g. cylinders or frustocones
• CPC Class Codes: A61F 2/4603 for insertion or extraction of endoprosthetic joints or of accessories thereof
• 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 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/3013 figure-"8"- or hourglass-shaped
• CPC Class Codes: A61F 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30148 : lozenge- or diamond-shaped
• CPC Class Codes: A61F 2002/3021 : frustoconical
• CPC Class Codes: A61F 2002/30217 : hollow cones, e.g. tubular-like cones
• CPC Class Codes: A61F 2002/30224 : cylindrical
• CPC Class Codes: A61F 2002/30235 : tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30405 : made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30426 : Bayonet coupling
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30604 : modular
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30795 : Blind bores, e.g. of circular cross-section
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• CPC Class Codes: A61F 2002/30808 : parallel
• CPC Class Codes: A61F 2002/3081 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30836 : knurled
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30879 : Ribs
• CPC Class Codes: A61F 2002/30892 : parallel
• CPC Class Codes: A61F 2002/30894 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30906 : shot- sand- or grit-blasted
• CPC Class Codes: A61F 2002/30909 : Nets
• 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 2002/449 : comprising multiple spinal implants located in different intervertebral spaces or in different vertebrae
• CPC Class Codes: A61F 2002/4619 : for extraction
• CPC Class Codes: A61F 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• CPC Class Codes: A61F 2002/4649 : Bone graft or bone dowel harvest sites
• CPC Class Codes: A61F 2002/4681 : by applying mechanical shocks, e.g. by hammering
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/001 : Figure-8-shaped, e.g. hourglass-shaped
• CPC Class Codes: A61F 2230/0013 : Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0067 : conical
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite

Abstract

The present invention is directed to a variety of interbody spinal fusion implants having at least a partially frusto-conical configuration. The spinal fusion implants of the present invention may be relatively solid or hollow and may have surface roughenings to promote bone ingrowth and stability. The spinal fusion implants of the present invention may have wells extending into the material of the implant from the surface for the purpose of holding fusion promoting materials and to provide for areas of bone ingrowth fixation. A variety of surface irregularities may be employed to increase implant stability and implant surface area, and/or for the purpose of advancing the spinal fusion implant into the fusion site.

Claims

1. An interbody spinal fusion implant for insertion across the surgically corrected height of a disc space between two adjacent vertebral bodies of a human spine, said implant comprising:

a leading end for insertion first into the disc space, a trailing end opposite said leading end, a length between said ends, and a mid-longitudinal axis passing through said leading and trailing ends, said leading end including an exterior surface being arcuate in both a first plane and a second plane adjacent the intersection of the mid-longitudinal axis therewith, said first plane and said second plane extending along the mid-longitudinal axis and being perpendicular to one another;

opposed upper and lower portions adapted to contact the adjacent vertebral bodies when implanted in the spine, said opposed upper and lower portions of said implant including at least one opening in communication with one another for permitting for the growth of bone from vertebral body to vertebral body through said implant; and

non-threaded bone engaging projections for engaging said implant to the adjacent vertebral bodies, said bone engaging projections extending from at least a portion of said opposed upper and lower portions, at least two of said bone engaging projections being formed as a frusto-conical segment, each of said frusto-conical segments having a forward-facing facet directed at least in part toward said leading end, each of said forward-facing facets having a slope, the slope of at least one of said forward-facing facets being different from the slope of another of said forward-facing facets of said frusto-conical segments.

2. The implant of claim 1, wherein said implant includes two opposed sides between said upper and lower portions, at least one of said sides being planar along at least a portion of the length.

3. The implant of claim 1, wherein said upper and lower portions form at least a portion of a cylinder.

4. The implant of claim 1, wherein said bone engaging projections include a plurality of ratchetings.

5. The implant of claim 1, wherein said implant has a hollow interior and an access opening for accessing said hollow interior.

6. The implant of claim 5, further comprising a cap for closing said access opening.

7. The implant of claim 1, wherein said trailing end is adapted to engage instrumentation for the insertion of said implant.

8. The implant of claim 1, wherein said implant is configured to be placed in close proximity in a side by side alignment to a second implant, said first and second implants when placed together having a combined overall width that is less than the sum of the individual maximum diameters of each of said first and second implants.

9. The implant of claim 1, wherein said upper and lower portions are at least in part arcuate.

10. The implant of claim 1, wherein said upper and lower portions are at least in part arcuate from side to side along at least a portion of the length of said implant.

11. The implant of claim 1, wherein said upper and lower portions are angled relative to one another so as to maintain an angulation of the adjacent vertebral bodies relative to one another.

12. The implant of claim 11, wherein said upper and lower portions are at least in part arcuate.

13. The implant of claim 1, wherein said upper and lower portions each include a portion that is an arc of the same circle.

14. The implant of claim 1, wherein each of said frusto-conical segments have a rearward-facing portion directed at least in part toward said trailing end and extending transversely to the mid-longitudinal axis.

15. The implant of claim 1, wherein each of said frusto-conical segments have a rearward-facing portion directed at least in part toward said trailing end, said rearward-facing portions having the same slope.

16. The implant of claim 1, wherein said frusto-conical segments are positioned one in front of another along the length of said implant.

17. The implant of claim 1, wherein said frusto-conical segments are immediately adjacent one another along the length of said implant.

18. The implant of claim 1, wherein the slope of said forward-facing facets of said frusto-conical segments decreases from one of said ends toward another of said ends.

19. The implant of claim 1, wherein the slope of said forward-facing facets of said frusto-conical segments decreases from said leading end toward said trailing end.