Apparatus for fusing adjacent bone structures

• US 5,968,098 A
• Filed: 10/22/1996
• Issued: 10/19/1999
• Est. Priority Date: 10/22/1996
• Status: Expired due to Term

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Surgical Dynamics Incorporated (Medtronic Plc)
• Inventors: Winslow, Charles J.
• Primary Examiner(s): Isabella, David J.
• Assistant Examiner(s): Koh, Choon P.
• Application Number:
  US08/734,911
• Time in Patent Office: 1,092 Days
• Field of Search: 623/16, 623/17, 623/18, 606/60, 606/61, 606/72, 606/73
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• 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 2/4611 of spinal prostheses
• 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 2002/30113 circular
• CPC Class Codes: A61F 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30228 Cylinders of elliptical or oval basis
• 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 2002/30593 hollow
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30622 Implant for fusing a joint or bone material
• CPC Class Codes: A61F 2002/30774 internally-threaded
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30863 : the entry end surface having flutes, relief grooves, starter notches or bevelled indentations
• 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 2002/4627 : 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 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0069 : cylindrical
• 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: Y10S 606/914 : Toolkit for installing or removing spinal positioner or stabilizer

Abstract

An apparatus for facilitating the fusion of adjacent bone structures includes an implant member configured for insertion within a space defined between adjacent bone structures. The implant member includes an entry end portion and a trailing end portion and defines a longitudinal axis. The implant member includes at least a longitudinal portion having a generally elliptical cross-sectional dimension with a major cross-sectional dimension greater than a minor cross-sectional dimension. The apparatus is particularly contemplated for fusion of adjacent vertebrae.

Claims

1. An apparatus for facilitating the fusion of adjacent bone structures comprising an implant member configured for insertion within a space defined between adjacent bone structures, the implant member including an entry end portion and a trailing end portion and defining a longitudinal axis, the implant member having a generally curved elliptical cross-sectional dimension transverse to the longitudinal axis along at least a portion of the length thereof, the entry end portion having a closed entry end surface.

11. The apparatus according to claim 1 wherein the implant member is configured for insertion within the intervertebral space defined between adjacent vertebrae.

2. An apparatus for facilitating the fusion of adjacent bone structures comprising an implant member configured for insertion within a space defined between adjacent bone structures, the implant member including an entry end portion and a trailing end portion and defining a longitudinal axis, the implant member having a generally curved elliptical cross-sectional dimension transverse to the longitudinal axis along at least a portion of the length thereof, the implant member further including an external surface portion having a threaded portion to facilitate insertion within the space defined between adjacent bone structures.

3. The apparatus according to claim 2 wherein the implant member includes a hollow interior cavity dimensioned to accommodate bone growth inducing substances.

4. The apparatus according to claim 3 wherein the implant member includes a plurality of apertures extending through an external surface portion in communication with the interior cavity, to thereby permit bone ingrowth to facilitate fusion of the adjacent bone structure.

5. The apparatus according to claim 2 wherein the entry end portion of the implant member defines a generally circular cross-sectional dimension transverse to the longitudinal axis to facilitate positioning between the adjacent bone structures.

6. The apparatus according to claim 3 wherein the implant member includes an exterior surface portion having at least one flute formed therein.

7. The apparatus according to claim 6 wherein the one flute is disposed adjacent the entry end portion and is formed in the threaded portion.

8. The apparatus according to claim 7 wherein the entry end portion includes a closed entry end surface.

9. The apparatus according to claim 8 wherein the one flute extends to the closed entry end surface.

10. An apparatus for facilitating the fusion of adjacent bone structures comprising an implant member configured for insertion within a space defined between adjacent bone structures, the implant member including an entry end portion and a trailing end portion and defining a longitudinal axis, the implant member having a generally curved elliptical cross-sectional dimension transverse to the longitudinal axis alone at least a portion of the length thereof, the implant member defining a hollow interior cavity dimensioned to accommodate bone growth inducing substances and a plurality of apertures extending through an external surface portion in communication with the interior cavity, to thereby permit bone ingrowth to facilitate fusion of the adjacent bone structure, and an end cap mountable to the trailing end portion of the implant member to enclose the interior cavity.

12. An apparatus for facilitating fusion of adjacent vertebrae of the spine, the adjacent vertebrae having an intervertebral disc space therebetween defining a disc height, the apparatus comprising an elongated implant member configured and dimensioned for insertion within the intervertebral space defined between adjacent vertebrae and defining a longitudinal axis, the implant member including a longitudinal section having a transverse cross-sectional dimension defining a generally curved elliptical configuration with a major axis and a minor axis to define a curved external wall portion of the longitudinal section, the implant member including an internal cavity for accommodating bone growth inducing substances and having a plurality of apertures extending through an external wall portion thereof in communication with the internal cavity, the longitudinal section of the implant member being dimensioned wherein upon positioning the implant member within the intervertebral space with the minor axis extending in the general direction of the axis of the spine, the longitudinal section at least spans the intervertebral space such that the curved external wall portion thereof contacts and supports the adjacent vertebrae, and generally maintains the disc height of the intervertebral disc space during healing.

13. An apparatus for facilitating fusion of adjacent vertebrae comprising an elongated implant member configured and dimensioned for insertion within an intervertebral space defined between adjacent vertebrae, the implant member having a transverse cross-sectional dimension defining a generally curved elliptical configuration along at least a section of the length thereof, the implant member including an internal cavity for accommodating bone growth inducing substances and having a plurality of apertures extending through an external wall portion thereof in communication with the internal cavity, and an external threaded portion for facilitating insertion within the intervertebral space.

14. The apparatus according to claim 13 wherein the implant member includes at least one flute, the one flute being formed in the threaded portion.

15. The apparatus according to claim 13 wherein the implant member includes an entry section having a closed entry end surface.

16. The apparatus according to claim 15 including at least one flute formed in the entry end surface.

17. The apparatus according to claim 13 wherein the implant member includes an entry end section, the entry end section having a transverse cross-sectional dimension defining a generally circular configuration.

18. The apparatus according to claim 13 further including an end cap mountable to the implant member to enclose the internal bore.

19. The apparatus according to claim 17, wherein the implant member includes a trailing end section and an intermediate section between the trailing end section and the entry end section, the entire intermediate section having a transverse cross-sectional dimension defining a generally elliptical configuration.

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

accessing the intervertebral space defined between adjacent vertebrae;

providing a fusion apparatus including an implant body having an entry end and a trailing end and defining a longitudinal axis, the implant body having a longitudinal section defining a general curved elliptical cross-sectional dimension with a major axis and a minor axis to define a curved outer surface of the longitudinal section of the implant body;

advancing the entry end of the implant body into the intervertebral space and positioning the implant body such that the curved outer surface of the implant body contacts the adjacent vertebrae; and

permitting bone ingrowth into contacting surfaces of the implant body to facilitate fusion of the adjacent vertebrae.

21. The method according to claim 20 wherein the step of advancing includes arranging the implant member within the intervertebral space whereby the major axis of the implant member is in general parallel relation with the vertebral end faces of the adjacent vertebrae and the minor axis extends in the general direction of the axis of the spine.

22. The method according to claim 20 including the step of introducing bone growth inducing substances within an internal cavity defined within the implant body whereby the adjacent vertebrae communicates with the bone growth inducing substances to form a solid fusion.

23. The method according to claim 22 wherein the implant body includes an exterior wall portion having apertures extending therethrough wherein the step of permitting bone ingrowth includes permitting bony tissue of the adjacent vertebrae to grow through the apertures to communicate with the bone growth inducing substances.

24. The method according to claim 23 wherein the implant body includes an external threaded portion, wherein the step of positioning includes screwing the implant body into a preformed receiving bore formed into the adjacent vertebrae.

25. The method according to claim 24 wherein the external threaded portion of the implant body includes a cutting thread wherein the step of screwing the implant body includes advancing the implant body within the preformed receiving bore whereby the cutting thread deburrs bone tissue to self-tap the implant body within the preformed receiving bore.

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

accessing the intervertebral space defined between adjacent vertebrae;

positioning a fusion apparatus into the intervertebral space, the fusion apparatus including an implant body having a longitudinal section defining a general curved elliptical transverse cross-section with a major axis greater than a minor axis, the implant being inserted laterally with respect to the longitudinal axis of the spine and positioned with the minor axis of the longitudinal section extending in the general direction of the longitudinal axis of the spine; and

permitting bone ingrowth into contacting surfaces of the implant body to facilitate fusion of the adjacent vertebrae.

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

accessing the intervertebral space of the lumbar spine defined between adjacent vertebrae; and

positioning a fusion apparatus into the intervertebral space of the lumbar spine and at an angle of between about 15° and

about 45°

with respect to the longitudinal axis of the spine and to the right of the great vessels when viewed anteriorly.

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

accessing the intervertebral space defined between adjacent vertebrae;

providing a fusion apparatus including an implant body having a longitudinal section defining a general curved elliptical transverse cross-section with a major axis greater than a minor axis, the implant body having an external threaded portion;

positioning the fusion apparatus within the intervertebral space by screwing the implant body into a preformed bore formed in the adjacent vertebrae; and

permitting bone ingrowth into contacting surfaces of the implant body to facilitate fusion of the adjacent vertebrae.