Intervertebral allograft spacer

• US 6,986,788 B2
• Filed: 04/09/2001
• Issued: 01/17/2006
• Est. Priority Date: 01/30/1998
• Status: Expired due to Term

• Current Assignee: Synthes USA LLC (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Paul, David C., Emch, Hansjuerg, Schenk, Beat
• Primary Examiner(s): GHERBI, SUZETTE JAIME J
• Application Number:
  US09/828,625
• Publication Number:
  US 20010049560A1
• Time in Patent Office: 1,744 Days
• Field of Search: 623 1611- 1716
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30724 Spacers for centering an implant in a bone cavity, e.g. in a cement-receiving cavity
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• 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 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• 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 2/4644 Preparation of bone graft, bone plugs or bone dowels, e.g. grinding or milling bone material bone material A61F2/28; disintegrating or milling devices B02C
• 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 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30057 made from both cortical and cancellous adjacent parts
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30075 swellable, e.g. when wetted
• CPC Class Codes: A61F 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/30126 : oval-O-shaped
• CPC Class Codes: A61F 2002/30133 : kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30153 : rectangular
• CPC Class Codes: A61F 2002/30158 : trapezoidal
• CPC Class Codes: A61F 2002/302 : toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30228 : Cylinders of elliptical or oval basis
• CPC Class Codes: A61F 2002/30233 : Stepped cylinders, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30235 : tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30237 : partial tubes
• CPC Class Codes: A61F 2002/3028 : polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30324 : differing in thickness
• CPC Class Codes: A61F 2002/30327 : differing in diameter
• CPC Class Codes: A61F 2002/30329 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2002/30331 : made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30354 : Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30367 : with additional means for preventing said rotation
• CPC Class Codes: A61F 2002/30383 : made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove
• CPC Class Codes: A61F 2002/30387 : Dovetail connection
• CPC Class Codes: A61F 2002/30433 : using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30448 : using adhesives
• CPC Class Codes: A61F 2002/30459 : stapled
• CPC Class Codes: A61F 2002/30462 : retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2002/30477 : using sharp protrusions, e.g. spikes, for anchoring into connecting prosthetic part
• CPC Class Codes: A61F 2002/30481 : using a locking clip
• CPC Class Codes: A61F 2002/30492 : using a locking pin
• CPC Class Codes: A61F 2002/30494 : Cooperating protrusions and recesses, e.g. radial serrations, located on abutting end surfaces of a longitudinal connection
• CPC Class Codes: A61F 2002/30507 : using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30515 : using a locking wedge or block
• 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 2002/30616 : Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30617 : Visible markings for adjusting, locating or measuring
• CPC Class Codes: A61F 2002/3071 : Identification means; Administration of patients
• CPC Class Codes: A61F 2002/30733 : Inserts placed into an endoprosthetic cavity, e.g. for modifying a material property
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30782 : inclined obliquely
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30787 : inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3082 : Grooves
• CPC Class Codes: A61F 2002/30828 : parallel
• 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 2002/30892 : 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 2002/30909 : Nets
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30971 : Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/30975 : made of two halves
• CPC Class Codes: A61F 2002/4635 : using minimally invasive surgery
• CPC Class Codes: A61F 2002/4649 : Bone graft or bone dowel harvest sites
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2210/0061 : swellable
• 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 2220/005 : using adhesives
• CPC Class Codes: A61F 2220/0066 : stapled
• CPC Class Codes: A61F 2220/0075 : sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2230/0004 : Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2250/0036 : differing in thickness
• CPC Class Codes: A61F 2250/0039 : differing in diameter
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2250/0089 : coded with symbols, e.g. dots, numbers, letters, words
• CPC Class Codes: A61F 2250/0097 : Visible markings, e.g. indicia
• CPC Class Codes: A61F 2310/00011 : Metals or 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 2310/00353 : Bone cement, e.g. polymethylmethacrylate or PMMA
• CPC Class Codes: B29C 33/26 : by pivotal movement
• CPC Class Codes: B29C 43/006 : Pressing and sintering powders, granules or fibres
• CPC Class Codes: B29L 2031/3041 : Trim panels

Abstract

An allogenic intervertebral implant for fusing vertebrae is disclosed. The implant is a piece of allogenic bone conforming in size and shape with a portion of an end plate of a vertebra. The implant has a wedge-shaped profile to restore disc height and the natural curvature of the spine. The top and bottom surfaces of the implant have a plurality of teeth to resist expulsion and provide initial stability. The implant according to the present invention provides initial stability need for fusion without stress shielding.

Claims

1. An intervertebral implant comprising a plug of allogenic bone conforming in size and shape with a portion of the end plates of adjacent vertebrae, wherein the top and bottom surfaces of the implant include a plurality of teeth provided in at least a two dimensional array with the teeth being spaced apart from one another for interlocking with the adjacent vertebrae, and wherein the teeth have a pyramidal shape profile defined by four sides meeting together to form a tip;

wherein the sides opposite each other form an acute angle of approximately 60 degrees at the tip.

2. The implant of claim 1 wherein the implant has an interior space for receiving osteoconductive material to promote the formation of new bone.

3. The implant of claim 2 wherein the osteoconductive material comprises bone chips.

4. The implant of claim 1 wherein the implant has a wedge-shaped profile to help restore disc height and spine curvature.

5. The implant of claim 1 wherein the implant is formed of more than one piece of allogenic bone.

6. The implant of claim 1 wherein the top and bottom surfaces are curved surfaces.

7. The implant of claim 1 wherein the teeth are integral with the top and bottom surfaces.

8. The implant of claim 1 wherein the teeth on the top and bottom surfaces are interrupted to form a channel to receive an insertion instrument for placing the implant.

9. A method for restoring disc height between adjacent vertebrae having facing endplates, the method comprising:

removing at least a portion of a disc located between the adjacent vertebrae;

distracting an inner space between the facing endplates; and

inserting the implant of claim 1 into the distracted inner space.

10. The method of claim 9 further comprising measuring a distance between the adjacent vertebrae with a preoperative lateral radiograph to determine an implant height.

11. The method of claim 9 wherein a distractor is used to distract the inner space.

12. The method of claim 11 further comprising inserting a trial spacer implant to determine an implant height.

13. The method of claim 9 wherein the implant further includes an interior space arid the method further comprises placing osteoconductive material into the interior space of the implant.

14. An implant for restoring disc height between adjacent vertebrae having facing endplates comprising an annular plug of allogenic bone surrounding an interior space, the plug having top and bottom surfaces configured and adapted in use to face the endplates of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in at least a two dimensional array, and wherein the teeth have a pyramidal shape defined by four sides meeting together to form a tip;

wherein the sides opposite each other form an acute angle of approximately 60 degrees at the tip.

15. The implant of claim 14 wherein the implant has a wedge-shaped profile to help restore disc height and spine curvature.

16. The implant of claim 15 wherein the top and bottom surfaces are curved surfaces.

17. The implant of claim 14 wherein the teeth are integral with the top and bottom surfaces.

18. The implant of claim 14 wherein the implant is formed of more than one piece of allogenic bone.

19. An intervertebral implant comprising at least one piece of allogenic bone provided with a hollow interior space, the implant having top and bottom surfaces configured and adapted in use to face the end plates of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in a plurality of adjacent rows, and wherein at least a portion of the teeth have a pyramidal shape defined by four sides meeting together to form a tip;

wherein the sides apposite each other form an acute angle at the tip;

the implant further comprising a pair of parallel channels extending along the entire length of the implant, the channels being substantially smooth, devoid of teeth, and being adapted and configured to receive a single surgical instrument.

20. The implant of claim 19, wherein the top and bottom surfaces each have an opening communicating with the hollow interior space.

21. The implant of claim 19, wherein the interior space and openings form a substantially cylindrical chamber.

22. The implant of claim 19, wherein the angle is approximately 60°

.

23. The implant of claim 19, wherein the implant is substantially symmetrical about a mid-plane of the implant.

24. The implant of claim 23, wherein the implant has a wedge shaped profile such that the top surface is inclined with reaped to the bottom surface.

25. The implant of claim 24, wherein the angle of inclination between the top surface and the midplane is between about 4.2°

and about 15°

.

26. The implant of claim 25, wherein the top and bottom surfaces are substantially flat planar surfaces.

27. The implant of claim 25, wherein the top and bottom surfaces are curved surfaces.

28. The implant of claim 19, wherein the implant has first and second sides and a gradual decrease in height from the first side to the second side.

29. The implant of claim 19, wherein the implant has at least one rounded edge between the top and bottom surfaces to facilitate insertion of the implant.

30. The implant of claim 19, further comprising at least two lateral sides wherein the channels are formed in the two lateral sides.

31. The implant of claim 19, wherein the implant is formed of more than one piece of bone.

32. The implant of claim 31, wherein the pieces of bone are arranged side by side and the top and bottom surfaces are formed of more than one piece of bone.

33. The implant of claim 19, wherein the teeth are arranged to cover substantially the entire top and bottom surfaces.

34. An intervertebral implant formed of at least one piece of allogenic bone provided with a hollow substantially cylindrical interior space, the implant comprising:

a mid-plane about which the implant is substantially symmetrical;

top and bottom surfaces configured and adapted in use to face the end plates of adjacent vertebrae, the top and bottom surface each having an opening communication with the substantially cylindrical space, and the top surface being inclined in a range between about 4.2° and

about 15°

with respect to the mid-plane;

at least two substantially smooth parallel channels adapted and configured to receive a surgical instrument; and

at least one rounded edge between the top and bottom surfaces to facilitate insertion of the implant;

wherein the top and bottom surfaces comprise a plurality of teeth provided in a plurality of adjacent rows, and further wherein the teeth are defined by four sides, at least three of the sides forming an acute angle with respect to the respective top and bottom surfaces.

35. The implant of claim 34, wherein the top and bottom surfaces are substantially flat planer surfaces.

36. The implant of claim 34, wherein the top and bottom surfaces are substantially flat in a first direction and curved in a second direction.

37. The implant of claim 34 formed of more than one piece of allogenic bone arranged side by side and adapted and configured such that the top and bottom surfaces are formed of more than one piece of bone.

38. The implant of claim 34, wherein the top and bottom surfaces are curved.

39. An intervertebral implant comprising a plug of allogenic bone conforming in size and shape with a portion of the end plates of adjacent vertebrae, wherein the top and bottom surfaces of the implant include a plurality of teeth provided in at least a two dimensional array with the teeth being spaced apart from one another for interlocking with the adjacent vertebrae, and wherein the teeth have a pyramidal shape profile defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant;

wherein the implant has a wedge-shaped profile such that the top surface is inclined with respect to the bottom surface at an angle of inclination of between about 4° and

about 15°

to help restore disc height and spine curvature.

40. An intervertebral implant comprising a plug of allogenic bone conforming in size and shape with a portion of the end plates of adjacent vertebrae, wherein the top and bottom surfaces of the implant include a plurality of teeth provided in at least a two dimensional array with the teeth being spaced apart from one another for interlocking with the adjacent vertebrae, and wherein the teeth have a pyramidal shape profile defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant;

wherein the implant is formed of more than one piece of allogenic bone.

41. The implant of claim 41, wherein the implant is formed of at least two pieces of bone and at least two pieces are connected by pins.

42. The implant of claim 42, wherein the pieces of bone are arranged side by side and the top and bottom surfaces are formed of more than one piece of bone.

43. An intervertebral implant comprising a plug of allogenic bone conforming in size and shape with a portion of the end plates of adjacent vertebrae, wherein the top and bottom surfaces of the implant include a plurality of teeth provided in at least a two dimensional array with the teeth being spaced apart from one another for interlocking with the adjacent vertebrae, and wherein the teeth have a pyramidal shape profile defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant;

wherein the top and bottom surfaces are curved surfaces.

44. A method for restoring disc height between adjacent vertebrae having facing endplates, the method comprising:

measuring a distance between the adjacent vertebrae with a preoperative lateral radiograph to determine an implant height;

removing at least a portion of a disc located between the adjacent vertebrae;

distracting an inner space between the facing endplates; and

inserting an intervertebral implant into the distracted inner space, the implant comprising a plug of allogenic bone conforming in size and shape with a portion of the end plates of adjacent vertebrae, wherein the top and bottom surfaces of the implant include a plurality of teeth provided in at least a two dimensional array with the teeth being spaced apart from one another for interlocking with the adjacent vertebrae, and wherein the teeth have a pyramidal shape profile defined by four sides fanning an acute angle with respect to the respective lop and bottom surfaces of the implant.

45. An implant for restoring disc height between adjacent vertebrae having facing endplates comprising an annular plug of allogenic bone surrounding an interior space, the plug having top and bottom surfaces configured and adapted in use to face the endplates of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in at least a two dimensional array, and wherein the teeth have a pyramidal shape defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant;

wherein the implant is formed of more than one piece of allogenic bone.

46. An intervertebral implant comprising at least one piece of allogenic bone provided with a hollow interior space, the implant having top and bottom surfaces configured and adapted in use to face the end plates of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in a plurality of adjacent rows, and wherein at least a portion of the teeth have a pyramidal shape defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant;

wherein;

the implant is substantially symmetrical about a mid-plane of the implant; and

the implant has a wedge shaped profile such that the top surface is inclined with respect to the bottom surface, an angle of inclination between the top surface and the midplane is between about 4.2° and

about 15°

.

47. The implant of claim 46, wherein the top and bottom surfaces are substantially flat planar surfaces.

48. The implant of claim 46, wherein th top and bottom surfaces are curved surfaces.

49. An intervertebral implant comprising at least one piece of allogenic bone provided with a hollow interior space, the implant having top and bottom surfaces configured and adapted in use to face the end plates of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in a plurality of adjacent rows, and wherein at least a portion of the teeth have a pyramidal shape defined by four sides meeting together to form a tip;

wherein the sides opposite each other form an acute angle of approximately 60°

at the tip;

wherein the implant has first and second sides and a gradual decrease in height from the first side to the second side.

50. An intervertebral implant comprising at least one piece of allogenic boric provided with a hollow interior space, the implant having top and bottom surfaces configured and adapted in use to face the end plates of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in a plurality of adjacent rows, and wherein at least a portion of the teeth have a pyramidal shape defined by four sides meeting together to form a tip;

wherein the sides opposite each other form an acute angle of approximately 60°

at the tip;

wherein the implant has at least one rounded edge between the top and bottom surfaces to facilitate insertion of the implant.

51. An intervertebral implant comprising:

at least one piece of allogenic bone provided with a hollow interior space, the implant having top and bottom surfaces configured and adapted in use to face the end plates of adjacent vertebrae; and

a pair of parallel channels adapted and configured to receive a single surgical instrument;

wherein;

the top and bottom surfaces include a plurality of teeth provided in a plurality of adjacent rows, and wherein at least a portion of the teeth have a pyramidal shape defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant; and

at least one channel extends along the entire length of the implant and is substantially devoid of teeth.

52. The implant of claim 51, further comprising at least two lateral sides wherein the channels are formed in the two lateral sides.

53. An intervertebral implant comprising at least one piece of allogenic bone provided with a hollow interior spare, the implant having top and bottom surfaces configured and adapted in use to face the end plates of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in a plurality of adjacent rows, and wherein at least a portion of the teeth have a pyramidal shape defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant;

wherein the implant is formed of more than one piece of bone.

54. The implant of claim 53, wherein the implant is formed of at least two pieces of bone and at least two pieces are connected by pins.

55. The implant of claim 54, the pieces of bone are arranged side by side and the top and bottom surfaces are formed of more than one piece of bone.

56. An implant for restoring disc height between adjacent vertebrae having facing endplates comprising an annular plug of allogenic bone surrounding an interior space, the plug having top and bottom surfaces configured and adapted in use to face the endplate of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in at least a two dimensional array, and wherein the teeth have a pyramidal shape defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant;

wherein;

the angle formed from the tip of the teeth to a base where the sides meet with the respective top and bottom surfaces is approximately 60 degrees; and

the implant bas a wedge-shaped profile to help restore disc height and spine curvature.

57. The implant of claim 56 wherein the top and bottom surfaces are curved surfaces.

58. An intervertebral implant comprising at least one piece of allogenic bone provided with a hollow interior space, the implant having top and bottom surfaces configured and adapted in use to face the end plates of adjacent vertebrae, wherein the top and bottom surfaces include a plurality of teeth provided in a plurality of adjacent rows, and wherein at least a portion of the teeth have a pyramidal shape defined by four sides forming an acute angle with respect to the respective top and bottom surfaces of the implant;

wherein the angle formed from the tip of the pyramidal teeth to a base where the sides meet with the respective top arid bottom surfaces is approximately 60°

.