Threaded frusto-conical spinal implants

• US 8,226,652 B2
• Filed: 11/14/2011
• Issued: 07/24/2012
• 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): Brown, Michael A.
• Application Number:
  US13/296,125
• Publication Number:
  US 20120053695A1
• Time in Patent Office: 253 Days
• Field of Search: 606/60, 606246-252, 606/279, 623/17.11, 623/17.16
• US Class Current: 606/60
• 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 17/3468 for implanting or removing devices, e.g. prostheses, implants, seeds, wires devices for implanting seeds A61M37/0069
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• 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 2/4637 for connecting or disconnecting two parts of a prosthesis
• 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 2002/30861 : having threads of increasing or decreasing height
• 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 2002/4627 : 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 2002/4629 : 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 2310/00293 : 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
• 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

The present invention is directed to a variety of interbody spinal fusion implants having at least a partially frusto-conical configuration. An external thread is employed to increase implant stability and implant surface area, and for the purpose of advancing the spinal fusion implant into the fusion site. 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.

Claims

1. A spinal implant for insertion within an implantation space formed into a segment of adjacent vertebral bodies of a human lumbar spine, said implant comprising:

a body having a leading end, a trailing end, a mid-longitudinal axis through said leading and trailing ends, a length parallel to the mid-longitudinal axis, and an arcuate sidewall surrounding the mid-longitudinal axis and extending from said leading end to said trailing end, said body having an interior surface and an opposite exterior surface, said arcuate sidewall having at least two apertures extending therethrough, said apertures being in communication with each other;

a first thread extending from said interior surface of said body proximate said trailing end, said first thread having a major diameter;

a second thread extending from said interior surface of said body, said second thread being spaced apart from said first thread, said second thread having a major diameter of a different size relative to the major diameter of said first thread; and

a third thread extending from said exterior surface of said body, said body having a frustoconical configuration along at least a portion of its length and over a plurality of turns of said third thread about the mid-longitudinal axis.

2. The implant of claim 1, wherein said implant is configured to space apart the adjacent vertebral bodies.

3. The implant of claim 1, wherein said implant is configured to distract apart the adjacent vertebral bodies using an element of rotation.

4. The implant of claim 1, wherein said third thread has a variable height along each turn of said third thread about the mid-longitudinal axis of said body.

5. The implant of claim 4, wherein said third thread has an outer locus with a substantially cylindrical configuration.

6. The implant of claim 1, wherein an outer locus of one of said threads has a substantially cylindrical configuration.

7. The implant of claim 1, wherein said first thread proximate said trailing end has an outer locus with a substantially cylindrical configuration.

8. The implant of claim 1, wherein said body has the frustoconical configuration along its length over at least eight turns of said third thread about the mid-longitudinal axis.

9. The implant of claim 1, wherein said body includes a central bore extending from said trailing end along the mid-longitudinal axis of said body, said central bore being configured to permit the delivery of bone growth promoting material to said apertures.

10. The implant of claim 1, wherein said trailing end is closed.

11. The implant of claim 1, wherein said leading end includes an aperture centered at the mid-longitudinal axis.

12. The implant of claim 1, wherein said body includes a central bore extending from said trailing end along the mid-longitudinal axis of said body, said arcuate sidewall having at least one well passing through said body and forming opposed apertures at said exterior surface of said sidewall, said well intersecting said central bore, said central bore being configured to permit delivery of bone growth promoting material to said apertures.

13. The implant of claim 12, wherein said leading end includes an aperture centered at the mid-longitudinal axis.

14. The implant of claim 12, wherein said arcuate sidewall includes a second well passing through said body and forming opposed apertures at said exterior surface of said sidewall, said second well intersecting said well.

15. The implant of claim 1, wherein the major diameter of said first thread proximate said trailing end is less than the major diameter of said second thread.

16. The implant of claim 1, wherein said first thread proximate said trailing end is configured to threadably engage an instrument to insert said implant into the spine.