Spinal implant

• US 8,858,638 B2
• Filed: 05/20/2013
• Issued: 10/14/2014
• 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): STEWART, ALVIN J
• Application Number:
  US13/897,728
• Publication Number:
  US 20130253652A1
• Time in Patent Office: 512 Days
• Field of Search: 623 1711- 1716
• US Class Current: 623/17.16
• 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 2/44 for the spine, e.g. vertebrae, spinal discs
• 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 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• 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 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30398 Sliding
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30579 with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30593 : hollow
• CPC Class Codes: A61F 2002/30599 : stackable
• 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 2002/30789 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30797 : internally-threaded
• CPC Class Codes: A61F 2002/30836 : knurled
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30843 : Pyramidally-shaped
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/3092 : having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/4485 : comprising three or more 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 2002/4629 : connected to the endoprosthesis or implant via a threaded connection
• 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 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• 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: Y10S 606/90 : Lumbar stabilizer
• CPC Class Codes: Y10S 606/907 : Composed of particular material or coated
• CPC Class Codes: Y10S 606/908 : Bioabsorbable material

Abstract

The present application is directed to interbody spinal fusion implants having a structural configuration that provides for the maintaining and creating of the normal anatomic angular relationship of two adjacent vertebrae of the spine to maintain and create spinal lordosis. The spinal fusion implants are sized to fit within the disc space created by the removal of disc material between two adjacent vertebrae and conform wholly or in part to the disc space created. The spinal fusion implants of the present invention have upper and lower surfaces that form a support structure for bearing against the end plates of the adjacent vertebrae. The upper and lower surfaces are disposed in a converging angular relationship to each other such that the implants have an overall “wedged-shape” in an elevational side view. The angular relationship of the upper and lower surfaces places and maintains the vertebrae adjacent to those surfaces in an angular relationship to each other, creating and maintaining the desired lordosis.

Claims

1. A spinal fusion implant for insertion between a first vertebra and a second vertebra adjacent the first vertebra, the first vertebra having a generally vertically extending first peripheral wall and a first endplate and the second vertebra having a generally vertically extending second peripheral wall and a second endplate, wherein the implant comprises:

a first terminal part defining a trailing face, a first bearing surface adapted to bear against a portion of the first endplate, and an opposite second bearing surface adapted to bear against a portion of the second endplate, said trailing face extending between said first bearing surface and said second bearing surface, said trailing face having a recessed portion and a threaded opening configured to receive an insertion instrument for inserting said implant between the first vertebra and the second vertebra;

a second terminal part opposite said first terminal part, said second terminal part having an insertion face extending between a third bearing surface adapted to bear against a portion of the first endplate and a fourth bearing surface adapted to bear against a portion of the second endplate, said implant having a longitudinal axis extending through said trailing face of said first terminal part and said insertion face of said second terminal part, and having a cross section in a first plane extending through said first bearing surface and said second bearing surface, and along the longitudinal axis, said implant having a length between said trailing face of said first terminal part and said insertion face of said second terminal part and parallel to the longitudinal axis, said implant having a width and a height each perpendicular to the length of said implant, the width of said implant being greater than the height of said implant;

a first side and an opposite second side, said first side and said second side extending from said first terminal part to said second terminal part, portions of said first side and said second side being substantially flat, said substantially flat portions intersecting a second plane that is perpendicular to the first plane and extends through said insertion face and said trailing face, wherein said substantially flat portions of said first side and said second side are symmetrical about the first plane;

an opening between said trailing face and said insertion face and between said first and second sides to permit for the growth of bone through said implant from the first vertebra to the second vertebra;

upper and lower bearing surfaces each having a length measured parallel to the longitudinal axis of said implant, said upper bearing surface being adapted to bear against a portion of the first endplate, said lower bearing surface being adapted to bear against a portion of the second endplate, said upper and lower bearing surfaces having portions proximate each of said first and second sides and being convex along the entire length of said upper and lower bearing surfaces relative to the second plane and in a direction parallel to the longitudinal axis, said convex portions of said upper and lower bearing surfaces having a convex curvature generally conforming to the first and second endplates, respectively, said trailing face having a height less than and measured parallel to a maximum height measured between said upper and lower bearing surfaces proximate one of said first and second sides;

a top including said first bearing surface, said third bearing surface, and said upper bearing surface, a bottom including said second bearing surface, said fourth bearing surface, and said lower bearing surface, said top and said bottom each having portions proximate each of said first and second sides and being convex relative to the second plane and in the direction parallel to the longitudinal axis, said convex portions of said top and said bottom having a convex curvature generally conforming to the first and second endplates, respectively, along a majority of the length of said implant, said convex portions of said top and said bottom including said convex portions of said upper and lower bearing surfaces, said opening extending through said implant from said top to said bottom;

ratchetings on each of said upper and lower bearing surfaces adapted to engage the first vertebra and the second vertebra, respectively, each of said ratchetings having a ridge oriented in a direction generally parallel to the width of said implant, said ratchetings on each of said upper and lower bearing surfaces having a forward facing facet facing an insertion direction and angled to afford forward movement of said implant and a rearward facing facet angled to prevent said implant from backing out in a direction opposite to the insertion direction; and

said opening of said implant being adapted to hold bone fusion promoting materials.

2. The implant of claim 1, wherein said implant has a plurality of openings between said trailing face and said insertion face and between said first and second sides to permit for the growth of bone through said implant from the first vertebra to the second vertebra.

3. The implant of claim 1, wherein said convex portions of said upper and lower bearing surfaces are convex along a continuous uninterrupted majority of the lengths of said upper and lower bearing surfaces, said convex portions of said upper and lower bearing surfaces being immediately adjacent said first and second sides.

4. A spinal fusion implant for insertion between a first vertebra and a second vertebra adjacent the first vertebra, the first vertebra having a generally vertically extending first peripheral wall and a first endplate and the second vertebra having a generally vertically extending second peripheral wall and a second endplate, wherein the implant comprises:

a first terminal part defining a trailing face, a first bearing surface adapted to bear against a portion of the first endplate, and an opposite second bearing surface adapted to bear against a portion of the second endplate, said trailing face extending between said first bearing surface and said second bearing surface, said trailing face having a recessed portion and a threaded opening configured to receive an insertion instrument for inserting said implant between the first vertebra and the second vertebra;

a second terminal part opposite said first terminal part, said second terminal part having an insertion face extending between a third bearing surface adapted to bear against a portion of the first endplate and a fourth bearing surface adapted to bear against a portion of the second endplate, said implant having a longitudinal axis extending through said trailing face of said first terminal part and said insertion face of said second terminal part, and having a cross section in a first plane extending through said first bearing surface and said second bearing surface, and along the longitudinal axis, said implant having a length between said trailing face of said first terminal part and said insertion face of said second terminal part and parallel to the longitudinal axis, said implant having a width and a height each perpendicular to the length of said implant;

a first side and an opposite second side, said first side and said second side extending from said first terminal part to said second terminal part, portions of said first side and said second side being substantially flat, said substantially flat portions intersecting a second plane that is perpendicular to the first plane and extends through said insertion face and said trailing face, wherein said substantially flat portions of said first side and said second side are symmetrical about the first plane;

an opening between said trailing face and said insertion face and between said first and second sides to permit for the growth of bone through said implant from the first vertebra to the second vertebra;

upper and lower bearing surfaces each having a length measured parallel to the longitudinal axis of said implant, said upper bearing surface being adapted to bear against a portion of the first endplate, said lower bearing surface being adapted to bear against a portion of the second endplate, said upper and lower bearing surfaces having portions proximate each of said first and second sides and being convex along the entire length of said upper and lower bearing surfaces relative to the second plane and in a direction parallel to the longitudinal axis, said convex portions of said upper and lower bearing surfaces having a convex curvature generally conforming to the first and second endplates, respectively, the width of said implant being greater than the height measured between said upper and lower bearing surfaces proximate one of said first and second sides of said implant;

a top including said first bearing surface, said third bearing surface, and said upper bearing surface, a bottom including said second bearing surface, said fourth bearing surface, and said lower bearing surface, said top and said bottom each having portions proximate each of said first and second sides and being convex relative to the second plane and in the direction parallel to the longitudinal axis, said convex portions of said top and said bottom having a convex curvature generally conforming to the first and second endplates, respectively, along a majority of the length of said implant, said convex portions of said top and said bottom including said convex portions of said upper and lower bearing surfaces, said opening extending through said implant from said top to said bottom;

ratchetings on each of said upper and lower bearing surfaces adapted to engage the first vertebra and the second vertebra, respectively, each of said ratchetings having a ridge oriented in a direction generally parallel to the width of said implant, said ratchetings on each of said upper and lower bearing surfaces having a forward facing facet facing an insertion direction and angled to afford forward movement of said implant and a rearward facing facet angled to prevent said implant from backing out in a direction opposite to the insertion direction; and

said opening of said implant being adapted to hold bone fusion promoting materials.

5. The implant of claim 4, wherein said implant has a plurality of openings between said trailing face and said insertion face and between said first and second sides to permit for the growth of bone through said implant from the first vertebra to the second vertebra.

6. The implant of claim 4, wherein said convex portions of said upper and lower bearing surfaces are convex along a continuous uninterrupted majority of the lengths of said upper and lower bearing surfaces, said convex portions of said upper and lower bearing surfaces being immediately adjacent said first and second sides.

7. A lordotic spinal fusion implant for insertion between a first vertebra and a second vertebra adjacent the first vertebra, the first vertebra having a generally vertically extending first peripheral wall and a first endplate and the second vertebra having a generally vertically extending second peripheral wall and a second endplate, wherein the implant comprises:

a first terminal part defining a trailing face, a first bearing surface adapted to bear against a portion of the first endplate, and an opposite second bearing surface adapted to bear against a portion of the second endplate, said trailing face extending between said first bearing surface and said second bearing surface;

a second terminal part opposite said first terminal part, said second terminal part having an insertion face extending between a third bearing surface adapted to bear against a portion of the first endplate and a fourth bearing surface adapted to bear against a portion of the second endplate, said implant having a longitudinal axis extending through said trailing face of said first terminal part and said insertion face of said second terminal part, and having a cross section in a first plane extending through said first bearing surface and said second bearing surface, and along the longitudinal axis, said implant having a length between said trailing face of said first terminal part and said insertion face of said second terminal part and parallel to the longitudinal axis, said implant having a width and a height each perpendicular to the length of said implant;

a first side and an opposite second side, said first side and said second side extending from said first terminal part to said second terminal part, portions of said first side and said second side being substantially flat, said substantially flat portions intersecting a second plane that is perpendicular to the first plane and extends through said insertion face and said trailing face, wherein said substantially flat portions of said first side and said second side are symmetrical about the first plane, said implant being adapted to be inserted between the first vertebra and the second vertebra with said first side and said second side of said implant being oriented toward the first endplate and the second endplate, respectively, and then rotated ninety degrees into an upright position, said trailing face having a recessed portion intersecting each of said first and second sides and being configured to receive an insertion instrument for inserting said implant between the first vertebra and the second vertebra;

an opening between said trailing face and said insertion face and between said first and second sides to permit for the growth of bone through said implant from the first vertebra to the second vertebra;

upper and lower bearing surfaces each having a length measured parallel to the longitudinal axis of said implant, said upper bearing surface being adapted to bear against a portion of the first endplate, said lower bearing surface being adapted to bear against a portion of the second endplate, said upper and lower bearing surfaces having portions proximate each of said first and second sides and being convex along the entire length of said upper and lower bearing surfaces relative to the second plane and in a direction parallel to the longitudinal axis, said convex portions of said upper and lower bearing surfaces having a convex curvature generally conforming to the first and second endplates, respectively, said trailing face having a height less than and measured parallel to a maximum height measured between said upper and lower bearing surfaces proximate one of said first and second sides, said upper and lower bearing surfaces being disposed in a converging angular relationship toward each other such that said implant appears wedge-shaped from a side view, the converging angular relationship of said upper and lower bearing surfaces maintaining the first vertebra and the second vertebra adjacent to said upper and lower bearing surfaces in an angular relationship to maintain the desired lordosis between the first vertebra and the second vertebra;

a top including said first bearing surface, said third bearing surface, and said upper bearing surface, a bottom including said second bearing surface, said fourth bearing surface, and said lower bearing surface, said top and said bottom each having portions proximate each of said first and second sides and being convex relative to the second plane and in the direction parallel to the longitudinal axis, said convex portions of said top and said bottom having a convex curvature generally conforming to the first and second endplates, respectively, along a majority of the length of said implant, said convex portions of said top and said bottom including said convex portions of said upper and lower bearing surfaces, said opening extending through said implant from said top to said bottom;

ratchetings on each of said upper and lower bearing surfaces adapted to engage the first vertebra and the second vertebra, respectively, each of said ratchetings having a ridge oriented in a direction generally parallel to the width of said implant, said ratchetings on each of said upper and lower bearing surfaces having a forward facing facet facing an insertion direction and angled to afford forward movement of said implant and a rearward facing facet angled to prevent said implant from backing out in a direction opposite to the insertion direction; and

said opening of said implant being adapted to hold bone fusion promoting materials.

8. The implant of claim 7, wherein said implant has a plurality of openings between said trailing face and said insertion face and between said first and second sides to permit for the growth of bone through said implant from the first vertebra to the second vertebra.

9. The implant of claim 7, wherein said convex portions of said upper and lower bearing surfaces are convex along a continuous uninterrupted majority of the lengths of said upper and lower bearing surfaces, said convex portions of said upper and lower bearing surfaces being immediately adjacent said first and second sides.

10. A spinal fusion implant for insertion between a first vertebra and a second vertebra adjacent the first vertebra, the first vertebra having a generally vertically extending first peripheral wall and a first endplate and the second vertebra having a generally vertically extending second peripheral wall and a second endplate, wherein the implant comprises:

a first terminal part defining a trailing face, a first bearing surface adapted to bear against a portion of the first endplate, and an opposite second bearing surface adapted to bear against a portion of the second endplate, said trailing face extending between said first bearing surface and said second bearing surface;

a second terminal part opposite said first terminal part, said second terminal part having an insertion face extending between a third bearing surface adapted to bear against a portion of the first endplate and a fourth bearing surface adapted to bear against a portion of the second endplate, said implant having a longitudinal axis extending through said trailing face of said first terminal part and said insertion face of said second terminal part, and having a cross section in a first plane extending through said first bearing surface and said second bearing surface, and along the longitudinal axis, said implant having a length between said trailing face of said first terminal part and said insertion face of said second terminal part and parallel to the longitudinal axis, said implant having a width and a height each perpendicular to the length of said implant;

a first side and an opposite second side, said first side and said second side extending from said first terminal part to said second terminal part, portions of said first side and said second side being substantially flat, said substantially flat portions intersecting a second plane that is perpendicular to the first plane and extends through said insertion face and said trailing face, wherein said substantially flat portions of said first side and said second side are symmetrical about the first plane, said implant being adapted to be inserted between the first vertebra and the second vertebra with said first side and said second side of said implant being oriented toward the first endplate and the second endplate, respectively, and then rotated ninety degrees into an upright position, said trailing face having a recessed portion intersecting each of said first and second sides and being configured to receive an insertion instrument for inserting said implant between the first vertebra and the second vertebra;

an opening between said trailing face and said insertion face and between said first and second sides to permit for the growth of bone through said implant from the first vertebra to the second vertebra;

upper and lower bearing surfaces each having a length measured parallel to the longitudinal axis of said implant, said upper bearing surface being adapted to bear against a portion of the first endplate, said lower bearing surface being adapted to bear against a portion of the second endplate, said upper and lower bearing surfaces having portions proximate each of said first and second sides and being convex along the entire length of said upper and lower bearing surfaces relative to the second plane and in a direction parallel to the longitudinal axis, said convex portions of said upper and lower bearing surfaces having a convex curvature generally conforming to the first and second endplates, respectively, said trailing face having a height less than and measured parallel to a maximum height measured between said upper and lower bearing surfaces proximate one of said first and second sides;

a top including said first bearing surface, said third bearing surface, and said upper bearing surface, a bottom including said second bearing surface, said fourth bearing surface, and said lower bearing surface, said top and said bottom each having portions proximate each of said first and second sides and being convex relative to the second plane and in the direction parallel to the longitudinal axis, said convex portions of said top and said bottom having a convex curvature generally conforming to the first and second endplates, respectively, along a majority of the length of said implant, said convex portions of said top and said bottom including said convex portions of said upper and lower bearing surfaces, said opening extending through said implant from said top to said bottom;

ratchetings on each of said upper and lower bearing surfaces adapted to engage the first vertebra and the second vertebra, respectively, each of said ratchetings having a ridge oriented in a direction generally parallel to the width of said implant, said ratchetings on each of said upper and lower bearing surfaces having a forward facing facet facing an insertion direction and angled to afford forward movement of said implant and a rearward facing facet angled to prevent said implant from backing out in a direction opposite to the insertion direction; and

said opening of said implant being adapted to hold bone fusion promoting materials.

11. The implant of claim 10, wherein said implant has a plurality of openings between said trailing face and said insertion face and between said first and second sides to permit for the growth of bone through said implant from the first vertebra to the second vertebra.

12. The implant of claim 10, wherein said convex portions of said upper and lower bearing surfaces are convex along a continuous uninterrupted majority of the lengths of said upper and lower bearing surfaces, said convex portions of said upper and lower bearing surfaces being immediately adjacent said first and second sides.