Apparatus for fusing adjacent bone structures

• US 6,979,353 B2
• Filed: 12/03/2001
• Issued: 12/27/2005
• Est. Priority Date: 12/03/2001
• Status: Expired due to Fees

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Inventors: Bresina, Stephen
• Primary Examiner(s): Philogene, Pedro
• Application Number:
  US10/004,969
• Publication Number:
  US 20030105527A1
• Time in Patent Office: 1,485 Days
• Field of Search: 623/17.11, 623/17.12, 623/17.13, 623/17.14, 623/17.15, 623/17.16, 606/61
• US Class Current: 623/17.16
• CPC Class Codes: A61B 17/1637 Hollow drills or saws producing a curved cut, e.g. cylindrical A61B10/025, A61B17/1695 take precedence
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• 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 2/4455 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 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• 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 2002/2839 Bone plugs or bone graft dowels
• CPC Class Codes: A61F 2002/30156 triangular
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30266 wedge-shaped parallelepipeds
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30565 having spring elements
• CPC Class Codes: A61F 2002/30593 hollow
• 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 2002/30774 internally-threaded
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30789 perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30818 : castellated or crenellated
• CPC Class Codes: A61F 2002/30827 : Plurality of grooves
• CPC Class Codes: A61F 2002/30843 : Pyramidally-shaped
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• 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 2002/4629 : 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 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0023 : triangular
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• 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 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00952 : Coating, pre-coating or prosthesis-covering structure made of bone cement, e.g. pre-applied PMMA cement mantle

Abstract

An apparatus for facilitating fusion of adjacent vertebrae includes an implant body dimensioned for positioning within an intervertebral space between upper and lower vertebrae to maintain the vertebrae in desired spaced relation to facilitate fusion thereof. The implant body includes lower and upper surfaces for engaging the respective lower and upper vertebrae and first and second side wall portions extending between the upper and lower surfaces. The first and second side wall portions are substantially solid. At least one of the first and second side wall portions have a substantially narrow longitudinal slit defined therein arranged to enhance flexibility of the one side wall portion. Preferably, each of the first and second side wall portions includes a longitudinal slit. The implant body may define an internal chamber dimensioned for reception of bone growth inducing substances. The implant body includes an internal bore extending through the upper and lower surfaces for reception of bone growth inducing substances. Preferably, the internal bore is cylindrical shaped to receive a cylindrical bone dowel harvested during the surgical procedure, or alternatively, to receive a prepackaged cylindrical rod containing bone growth inducing substances. A plurality of internal bores may be provided in side by side relation.

Claims

1. An apparatus for facilitating fusion of adjacent vertebrae, comprising:

an implant body dimensioned for positioning within an intervertebral space between upper and lower vertebrae to maintain the vertebrae in desired spaced relation to facilitate fusion thereof, said implant body including lower and upper surfaces for engaging the respective lower and upper vertebrae, and first and second side wall portions extending between said upper and lower surfaces, said first and second side wall portions being substantially solid, at least one of said first and second side wall portions having a substantially narrow longitudinal slit defined therein arranged to enhance flexibility of said one side wall portion wherein said implant body includes two or more bores extending through said upper and lower surfaces for reception of bone growth inducing substances, said bores having intersecting wall portions forming a communication path extending from said upper to said lower surface, said bores in communication with said slit.

2. The apparatus according to claim 1 wherein each of said first and second side wall portions includes said longitudinal slit.

3. The apparatus according to claim 1 wherein said two or more bores of said implant body are generally cylindrically-shaped bores.

4. The apparatus according to claim 3 wherein said generally cylindrically-shaped internal bores are arranged in adjacent side by side relation and have open sides forming the communication path to adjacent bores.

5. The apparatus according to claim 1 wherein said upper and lower surfaces include a plurality of ridges, said ridges dimensioned to engage the respective upper and lower vertebrae to facilitate retention within the intervertebral space.

6. The apparatus according to claim 1 wherein said upper and lower surfaces include a plurality of grooves defined therein, said grooves defining surfaces dimensioned to engage the respective upper and lower vertebrae to facilitate retention within the intervertebral space.

7. The apparatus according to claim 1 wherein said implant body includes leading and trailing end portions, at least one of said leading and trailing end portions having a tapered surface.

8. The apparatus according to claim 7 wherein said one of said leading and trailing end portions includes upper and lower tapered surfaces.

9. The apparats according to claim 8 wherein each said leading and trailing end portions include said upper and lower tapered surfaces.

10. The apparatus according to claim 3 further including a bone growth inducing substance disposed within said cylindrically-shaped bore, said bone growth inducing substance defining a substantially cylindrically-shape corresponding to said cylindrically-shaped internal, bore of said implant body.

15. The apparatus as set forth in claim 3 wherein there are three internal bores further including a generally cylindrical bone substitute plug within each of said generally cylindrical internal bores.

16. The apparatus as set forth in claim 15 wherein the cylindrical internal bores are arranged in adjacent side by side relationship.

24. The apparatus as set forth in claim 1 wherein said implant includes three bores.

11. A method for fusion of adjacent vertebrae, comprising the steps of:

accessing the intervertebral space defined between adjacent vertebrae;

providing an implant including an implant body having lower and upper surfaces and first and second side wall portions extending between said upper and lower surfaces, said first and second side wall portions being substantially solid, at least one of said first and second side wall portions having a substantially narrow longitudinal slit defined therein arranged to enhance flexibility of said one side wall portion, said implant having an internal cavity formed by at least two bores extending between the upper and lower surface in communication with said slit said bores having side walls in continuous communication between said upper and lower surfaces; and

positioning said implant within the intervertebral space whereby said upper and lower surfaces engage upper and lower vertebral portions of adjacent vertebrae in supporting relation therewith while said longitudinal slit permits compressive movement of said implant body in response to a load exerted by the vertebral portions.

12. The method according to claim 11 further including the step of introducing bone growth inducing substances within said at least two bores to facilitate fusion whereby said implant body and said bone growth inducing substances share the load exerted by the vertebral portions.

13. The method according to claim 12 wherein said implant body defines at least two generally cylindrically-shaped bores extending through said upper and lower surfaces and further including the step of harvesting a substantially cylindrically-shaped bone graft for positioning within said bore.

14. The method according to claim 13 wherein the step of harvesting includes using a trephine to harvest the bone graft.

17. A kit for fusion of adjacent vertebra comprising:

a plurality of implants, each having an implant body including upper and lower surfaces for engaging respective adjacent vertebra and sidewall positions extending between said upper and lower surfaces and surrounding an internal cavity having a plurality of generally cylindrical internal bores open to said upper and lower surfaces, said bores having sides in open communication with adjacent bores continuously from the upper to the lower surface of the implant; and

a plurality of bone plugs sized to fit into each of said cylindrical internal bores.

18. The kit as set forth in claim 17 wherein each implant internal cavity has three internal bores and a plug is provided for fitting into each bore.

19. The kit as set forth in claim 17 wherein the bone plug material is selected from the group consisting of allograft bone, autograft bone, bone morphogenic proteins, bioceramics and hydroxyapatite.

20. The kit as set forth in claim 19 wherein each of said plurality of implant bodies includes a slit in the sidewall in communication with said generally cylindrical bores.

21. An apparatus for facilitating fusion of adjacent vertebrae, comprising:

an implant body dimensioned for positioning within an intervertebral space between upper and lower vertebrae to maintain the vertebrae in desired space relation to facilitate fusion thereof, said implant body including lower and upper surfaces for engaging the respective lower and upper vertebrae, and first and second side wall portions extending between said upper and lower surfaces, said first and second side wall portions being substantially solid wherein said body has an internal cavity formed by three bores extending between the upper and lower surface, said bores having sidewalls in open communication with adjacent bores.

22. The apparatus as set forth in claim 21 wherein said first and second sidewalls have a longitudinal slit in communication with each of said bores.

23. The apparatus as set forth in claim 22 wherein said bores are generally cylindrical.