Spinal cage insert, filler piece and method of manufacturing

• US 20050177237A1
• Filed: 10/18/2004
• Published: 08/11/2005
• Est. Priority Date: 04/12/2001
• Status: Abandoned Application

• Current Assignee: Therics Inc.
• Original Assignee: AFBS, Inc.
• Inventors: Pryor, Timothy, Shappley, Ben, Materna, Peter A., Blum, John, Hatcher, Thomas James, West, Thomas George, McGlohorn, Jonathan, Saini, Sunil, Bradbury, Thomas J., Recber, Ali Cem
• Application Number:
  US10/966,109
• Publication Number:
  US 20050177237A1
• Time in Patent Office: Days
• US Class Current: 623/17.110
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• 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 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 2002/30059 differing in bone mineralization, e.g. made from both mineralized and demineralized adjacent parts
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30263 cubical
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30403 Longitudinally-oriented cooperating ribs and grooves on mating lateral surfaces of a mainly longitudinal connection
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30599 stackable
• CPC Class Codes: A61F 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30807 Plurality of blind bores
• CPC Class Codes: A61F 2002/30813 : Stepped or enlarged blind bores, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30822 : Circumferential grooves
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30985 : using three dimensional printing [3DP]
• 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 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2230/0084 : cubical
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite

Abstract

A spinal cage insert for a spinal cage is provided. The spinal cage insert has a shape suitable to be inserted into and fit closely in an interior of the spinal cage. The insert may comprise a member of the calcium phosphate family. The spinal cage insert may be made to a desired shape of porous ceramic, and it may include channels and/or surface features. Various shapes of filler pieces are also provided, wherein the filler pieces may be suitable to augment external regions of vertebrae which have been fused to each other so as to promote build-up of bone. The spinal cage insert and/or the filler pieces may be osteoconductive and may also contain osteoinductive substances or material. The articles may also contain cavities suitable for containing particles of demineralized bone matrix (DBM). Methods of use and methods of manufacturing the spinal cage insert and filler pieces are also provided.

Claims

1. A spinal cage insert for a spinal cage, wherein the spinal cage insert has a shape of dimensions substantially equal to those of an interior of the spinal cage, and wherein the spinal cage insert comprises a member of the calcium phosphate family.

2. The spinal cage insert of claim 1, wherein the calcium phosphate comprises tricalcium phosphate.

3. The spinal cage insert of claim 1, wherein the spinal cage insert has pores which are suitable to wick bodily fluids.

4. The spinal cage insert of claim 1, wherein the spinal cage insert has pores which make up between 20% and 45% by volume of the entire spinal cage insert.

5. The spinal cage insert of claim 1, wherein the spinal cage insert has pores which have a pore size distribution which has a peak between 8 micrometers and 20 micrometers.

6. The spinal cage insert of claim 1, wherein the spinal cage insert has pores which have a mean pore size of approximately 60 micrometers.

7. The spinal cage insert of claim 1, wherein the spinal cage insert has pores which range from approximately 1 micrometer to approximately 300 micrometers.

8. The spinal cage insert of claim 1, wherein the spinal cage insert has at least one of recessed surface features and channels therethrough.

9. The spinal cage insert of claim 8, wherein the spinal cage has perforations or openings, and at least some of the at least one of recessed surface features and channels coincide with at least some of the perforations or openings in the spinal cage when the spinal cage insert is installed in the spinal cage.

10. The spinal cage insert of claim 9, wherein the spinal cage insert and the interior of the spinal cage are rotationally non-symmetric.

11. The spinal cage insert of claim 9, wherein the spinal cage insert and the interior of the spinal cage are rotationally symmetric.

12. The spinal cage insert of claim 1, wherein the spinal cage insert is suitable to be inserted into the spinal cage with a translational motion.

13. The spinal cage insert of claim 1, wherein the spinal cage insert is suitable to be inserted into the spinal cage with simultaneous translational and rotational motion, wherein the translational motion is along a length axis of the spinal cage insert, and the rotational motion is around the length axis of the spinal cage insert.

14. The spinal cage insert of claim 1, wherein the spinal cage insert is suitable to be inserted into the spinal cage with translational motion followed by rotational motion.

15. The spinal cage insert of claim 1, wherein the spinal cage insert fits into the spinal cage with a frictional fit.

16. The spinal cage insert of claim 1, wherein the spinal cage insert has a taper on at least one external surface suitable to frictionally engage the spinal cage.

17. The spinal cage insert of claim 1, wherein the spinal cage insert has at least one of ribs and protrusions.

18. The spinal cage insert of claim 17, wherein the at least one of ribs and protrusions interfere with the spinal cage when the spinal cage insert is in the spinal cage, and wherein the at least one of ribs and protrusions are crushable.

19. The spinal cage insert of claim 1, wherein the spinal cage insert comprises at least two parts which together are suitable to be inserted into and fit closely in the interior of the spinal cage.

20. The spinal cage insert of claim 1, wherein the spinal cage insert is suitable to be broken into at least two parts which together are suitable to be inserted into and fit closely in the interior of the spinal cage.

21. The spinal cage insert of claim 1, wherein the spinal cage insert has a chamfer or taper on at least one external surface usable to guide the spinal cage insert into the spinal cage.

22. The spinal cage insert of claim 1, wherein the spinal cage insert has at least one carrying feature suitable to allow the spinal cage insert to be at least one of gripped or carried by a tool.

23. The spinal cage insert of claim 1, wherein the spinal cage insert is suitable to be trapped inside the spinal cage by a locking component which couples to both the spinal cage and the spinal cage insert.

24. The spinal cage insert of claim 1, further comprising at least one bioactive substance.

25. The spinal cage insert of claim 1, wherein the spinal cage insert is made by methods which include three dimensional printing.

40. The spinal cage insert of claim 1, wherein the spinal cage insert is made by methods which include molding.

41. A kit comprising the spinal cage insert of claim 1 and at least one item selected from the group consisting of:

a matched spinal cage;

tooling suitable for installing the spinal cage insert into the spinal cage;

tooling suitable for installing the spinal cage into a patient;

a spreader for spreading apart subcomponents of the spinal cage insert;

one or more other surgical instruments;

a substance suitable for adhering the spinal cage insert to the spinal cage; and

at least one other substance suitable for use during surgery.

42. A kit comprising the spinal cage insert of claim 25 and at least one item selected from the group consisting of:

a matched spinal cage;

tooling suitable for installing the spinal cage insert into the spinal cage;

tooling suitable for installing the spinal cage into a patient;

a spreader for spreading apart subcomponents of the spinal cage insert;

at least one other surgical instruments;

a substance suitable for adhering the spinal cage insert to the spinal cage; and

other substances suitable for use during surgery.

26. A spinal cage insert for a spinal cage, wherein the spinal cage insert has a shape suitable to be inserted into and fit closely in an interior of the spinal cage, and wherein the spinal cage insert comprises demineralized bone matrix.

27. The spinal cage insert of claim 26, wherein the spinal cage insert comprises pores.

28. The spinal cage insert of claim 27, wherein the pores are suitable to wick bodily fluids.

29. The spinal cage insert of claim 26, wherein the spinal cage insert has recessed surface features or channels therethrough.

30. The spinal cage insert of claim 26, further comprising at least one bioactive substance.

36. The spinal cage insert of claim 26, wherein the spinal cage insert is made by methods which include three dimensional printing.

39. The spinal cage insert of claim 26, wherein the spinal cage insert is made by methods which include molding.

43. A kit comprising the spinal cage insert of claim 30 and at least one item selected from the group consisting of:

a matched spinal cage;

tooling suitable for installing the spinal cage insert into the spinal cage;

tooling suitable for installing the spinal cage into a patient;

a spreader for spreading apart subcomponents of the spinal cage insert;

other surgical instruments;

a substance suitable for adhering the spinal cage insert to the spinal cage; and

at least one second substance suitable for use during surgery.

31. A spinal cage insert for a spinal cage, wherein the spinal cage insert has a shape suitable to be inserted into and fit closely in an interior of the spinal cage, and wherein the spinal cage insert has surface recesses or channels therethrough.

32. The spinal cage insert of claim 31, wherein the surface recesses or channels have a smallest dimension along a surface of the spinal cage insert, wherein the smallest dimension is in the range from approximately 50 micrometers to approximately 3000 micrometers.

33. The spinal cage insert of claim 32, wherein the spinal cage insert has pores.

34. The spinal cage insert of claim 33, wherein the pores are suitable to wick bodily fluids.

35. The spinal cage insert of claim 31, further comprising at least one bioactive substance.

37. The spinal cage insert of claim 31, wherein the spinal cage insert is made by methods which include three dimensional printing.

38. The spinal cage insert of claim 31, wherein the spinal cage insert is made by methods which include molding.

44. A method of manufacturing a spinal cage insert, the method comprising:

depositing a layer of powder having powder particles, wherein the powder particles comprise at least one member of the calcium phosphate family;

depositing onto the layer of powder in appropriate places a binder liquid suitable to bind powder particles other powder particles;

repeating the above steps as needed to form a bound shape which is a spinal cage insert; and

separating the bound shape from unbound powder.

45. The method of claim 44, wherein depositing the binder liquid is done in a pattern suitable to create a bound shape having surface recesses or internal channels.

46. The method of claim 44, wherein depositing the powder particles comprises depositing powder particles which have a mean size in the range of 20 micrometers to 40 micrometers.

47. The method of claim 44, further comprising after separating the bound shape from the unbound powder, heating the bound shape suitably to partially sinter the bound shape.

48. A method of manufacturing a spinal cage insert, the method comprising:

depositing a layer of powder comprising powder particles, wherein the powder particles comprise precursors of at least one member of the calcium phosphate family;

depositing onto the layer of powder in appropriate places a binder liquid suitable to bind powder particles to other powder particles;

repeating the above steps as needed to form a bound shape which is a spinal cage insert;

separating the bound shape from unbound powder; and

heating the bound shape suitably both to cause reaction between the precursors in the powder and to partially sinter the bound shape.

49. The method of claim 48, wherein depositing the powder particles comprises depositing powder particles which have a mean size in the range of approximately 10 micrometers.

50. The method of claim 48, further comprising heating the bound shape to a temperature sufficient to cause the precursors to react to form a desired ceramic.

51. The method of claim 48, wherein the precursors react to form a desired ceramic at a temperature between 1100 C and 1300 C.

52. The method of claim 48, wherein the precursors comprise hydroxyapatite and dicalcium phosphate.

53. The method of claim 48, wherein depositing the powder particles comprises depositing powder particles which further comprise a decomposable porogen.

54. The method of claim 53, wherein the particles of the precursors have a first average particle size, and the particles of the decomposable porogen have a second average particle size, and the second average particle size is at least approximately 5 times as large as the first particle size.

55. A method of manufacturing a spinal cage insert, the method comprising:

depositing a layer of powder comprising powder particles, wherein the powder particles comprise particles of demineralized bone matrix;

depositing onto the layer of powder in appropriate places a binder liquid suitable to bind powder particles to other powder particles;

repeating the above steps as needed to form a bound shape which is a spinal cage insert; and

separating the bound shape from unbound powder.

56. The method of claim 55, wherein depositing the binder liquid is done in a pattern suitable to create a bound shape having surface recesses or internal channels.

57. The method of claim 55, wherein depositing the powder particles comprises depositing powder particles which have a mean size in the range of approximately 200 micrometers.

58. A method of making a spinal cage insert, the method comprising:

depositing a layer of a powder comprising particles of a biocompatible substance and particles of a decomposable porogen suitable to decompose into gaseous decomposition products;

depositing onto the layer of powder in appropriate places a binder liquid suitable to bind powder particles other powder particles;

repeating the above steps as needed to form a bound shape which is a spinal cage insert;

separating the bound shape from unbound powder; and

heating the bound shape to a temperature sufficient to thermally decompose the decomposable porogen into gaseous decomposition products.

59. The method of claim 58, wherein the particles of the biocompatible substance have a first average particle size, and the particles of the decomposable porogen have a second average particle size, and the second average particle size is at least 5 times as large as the first particle size.

60. The method of claim 58, wherein the biocompatible substance is tricalcium phosphate.

61. The method of claim 58, wherein the porogen comprises lactose or another sugar.

62. A method of making a spinal cage insert, the method comprising:

forming powder into a desired shape, wherein the powder comprises precursors suitable to react to form a desired ceramic comprised in a spinal cage insert; and

heating the precursors to a temperature suitable to cause the precursors to react.

63. A method of making a spinal cage insert, the method comprising:

forming powder into a desired shape, wherein the powder comprises a decomposable porogen; and

heating the powder to a temperature suitable to decompose the decomposable porogen, wherein the decomposed porogen is comprised in a spinal cage insert.

64. A spinal cage insert for a spinal cage, wherein the spinal cage insert has a shape of dimensions substantially equal to those of an interior of the spinal cage, and wherein the spinal cage insert comprises a member of the calcium phosphate family, and wherein the spinal cage insert further comprises an internal cavity.

65. The spinal cage insert of claim 64, further comprising particles of demineralized bone contained inside the internal cavity.

66. The spinal cage insert of claim 65, further comprising a cap suitable to close the internal cavity.

67. The spinal cage insert of claim 66, wherein the cap comprises gelatin.

68. The spinal cage insert of claim 67, wherein the gelatin is in a dried state.

69. The spinal cage insert of claim 67, wherein the gelatin is in a gel state.

70. The spinal cage insert of claim 66, wherein the cap comprises gelatin which partially interpenetrates the spinal cage insert.

71. A bone filler piece which comprises a structure which is osteoconductive and which defines at least one macroscopic internal feature, wherein at least one macroscopic internal feature contains demineralized bone matrix.

72. The filler piece of claim 71, wherein the structure comprises beta tricalcium phosphate.

73. The filler piece of claim 71, wherein the structure comprises pores having an average pore dimension, and wherein at least one macroscopic internal feature has all dimensions greater than three times the average pore dimension.

74. The filler piece of claim 71, wherein at least one macroscopic internal feature has all dimensions greater than approximately 100 micrometers.

75. The filler piece of claim 71, wherein at least one macroscopic interior feature is accessible to an exterior of the filler piece.

76. The filler piece of claim 71, wherein at least one macroscopic internal feature is selected from the group consisting of a channel, a groove and an internal cavity.

77. The filler piece of claim 71, wherein at least one macroscopic internal feature, having feature internal dimensions, is connected to an exterior of the filler piece by a channel whose internal cross-section dimensions are smaller than the feature internal dimensions.

78. The filler piece of claim 71, wherein at least a majority of the demineralized bone matrix exists in the form of particles having all of their dimensions greater than approximately 100 micrometers.

79. The filler piece of claim 71, wherein the structure comprises pores having pore sizes between 1 micrometer and 1000 micrometers.

80. The filler piece of claim 71, wherein the structure comprises a single piece.

81. The filler piece of claim 71, wherein the structure comprises two or more pieces suitable to be joined together.

82. The filler piece of claim 81, wherein at least one of the pieces has a closed end.

83. The filler piece of claim 71, further comprising a cap suitable to close the macroscopic internal feature.

84. The filler piece of claim 83, wherein the cap comprises dried gelatin.

85. The filler piece of claim 83, wherein the cap comprises gelatin in a gel state.

86. The filler piece of claim 71, wherein the structure comprises particles partially joined to other particles.

87. The filler piece of claim 86, wherein the particles are joined to other particles by necks having a composition which is substantially the same as the composition of the particles.

88. The filler piece of claim 86, wherein the particles are joined to to other particles by necks having a composition which is different from the composition of the particles.

89. The filler piece of claim 71, wherein the filler piece further comprises, in at least some space not occupied by any other materials, a third material.

90. The filler piece of claim 71, wherein the filler piece is configured suitably to augment a vertebra or vertebrae of the spine.

91. A filler piece for augmenting exteriors of vertebrae, comprising a porous osteoconductive ceramic material shaped suitably to fit adjacent to more than one vertebrae.

92. The filler piece of claim 91, wherein the filler piece is shaped to fit between a spinous process and a transverse process of a vertebra.

93. The filler piece of claim 91, wherein the filler piece is shaped to fit in place of at least a portion of a spinous process of a vertebra.

94. The filler piece of claim 91, wherein the filler piece is shaped to fit between a spinous process and a transverse process of more than one vertebrae.

95. The filler piece of claim 91, wherein the filler piece is shaped to fit in place of at least a portion of a spinous process of more than one vertebrae.

96. The filler piece of claim 91, wherein the filler piece comprises more than one individual piece suitable to fit into each other.

97. The filler piece of claim 96, wherein one filler piece comprises a concave chamfer and a neighboring filler piece comprises a convex chamfer.

98. The filler piece of claim 96, wherein one filler piece comprises a post and a neighboring filler piece comprises a cylindrical empty space suitable to receive the post or a step, wherein one filler piece comprises a post or a step, and a neighboring filler piece comprises a cylindrical empty space suitable to receive the post or step.

99. The filler piece of claim 96, wherein a first filler piece comprises teeth and a neighboring filler piece comprises teeth configured to engage the teeth on the first filler piece.

100. The filler piece of claim 91, wherein the filler piece comprises at least one internal cavity suitable for containing an osteoinductive material.

101. The filler piece of claim 100, further comprising a cap suitable to close the internal cavity.

102. The filler piece of claim 100, wherein the cap comprises gelatin.

103. The filler piece of claim 100, wherein the gelatin interpenetrates with a portion of the filler piece.

104. The filler piece of claim 91, wherein the filler piece further comprises an osteoinductive material.

105. The filler piece of claim104, wherein the osteoinductive material comprises demineralized bone matrix.

106. A method of manufacturing a filler piece, the method comprising:

manufacturing a structure which is osteoconductive and which comprises macroscopic internal features; and

depositing into at least some of the macroscopic internal features a composition comprising particles of osteoinductive material;

closing the macroscopic internal features suitably to contain the particles of osteoinductive material.

107. The method of claim 106, wherein closing the macroscopic internal features comprises applying a cap.

108. The method of claim 106, wherein closing the macroscopic internal features comprises applying a cap which comprises gelatin.

109. The method of claim 106, wherein applying the cap comprises interpenetrating a fluid material into a portion of the structure.

110. The method of claim 106, further comprising, after applying the cap, drying the cap.

111. The method of claim 106, wherein manufacturing the structure comprises manufacturing a structure which has both macroscopic internal features of suitable size for depositing demineralized bone matrix and macroscopic internal features which are too small for depositing demineralized bone matrix.

112. The method of claim 106, wherein manufacturing the structure comprises manufacturing a sturcture in two or more parts suitable to assemble to form the filler piece.

113. The method of claim 106, wherein manufacturing the structure comprises three dimensional printing.

114. The method of claim 106, wherein manufacturing the structure comprises molding.

115. The method of claim 106, wherein manufacturing the structure comprises removing material.

116. The method of claim 106, wherein manufacturing the structure comprises three dimensional printing onto a powder which comprises a porogen which is suitable to decompose into gaseous decomposition products at a suitable temperature.

117. The method of claim 106, wherein manufacturing the structure comprises three dimensional printing onto a powder which comprises precursors suitable to react to form a desired ceramic substance.

118. The method of claim 106, wherein the powder comprises precursors suitable to react to form tricalcium phosphate and also comprises an amount of calcium pyrophosphate.

119. The method of claim 106, further comprising, after all the listed steps, infiltrating another substance into space not occupied by any other substance.

120. A filler piece made by the method of claim 106.

121. A method of augmenting exteriors of vertebrae, comprising:

mechanically anchoring adjacent vertebrae to each other; and

installing, adjacent to external surfaces of vertebrae, a filler piece comprising a synthetic porous osteoconductive material having a definite shape suitable to cause bone to grow joining the adjacent vertebrae to each other.

122. The method of claim 121, wherein installing the filler piece comprises installing the filler piece in space between a spinous process and a transverse process.

123. The method of claim 121, wherein installing the filler piece comprises removing bone from the vertebrae.

124. The method of claim 121, wherein installing the filler piece comprises installing the filler piece in a region normally occupied by a spinous process.

125. The method of claim 121, wherein installing the filler piece comprises installing a filler piece which further comprises osteoinductive material.

126. The method of claim 121, wherein the osteoinductive material comprises demineralized bone matrix.

127. The method of claim 121, wherein the filler piece comprises an internal cavity containing demineralized bone matrix.

128. The method of claim 127, wherein the filler piece further comprises a cap suitable to close the internal cavity.

129. The method of claim 128, wherein the cap comprises gelatin.

130. The methods of any one of claims 44, 62, 63, and 121, wherein the powder comprises precursors of at least one member of the calcium phosphate family, and wherein the powder comprises a composition in the proportions of about 58.2% precursors, about 38.8% lactose, and about 3% calcium pyrophosphate.