IMPLANTS GALBES DE FUSION SPINALE

CONTOURED SPINAL FUSION IMPLANTS

Abrégé français

L'invention porte sur un implant intermédiaire se posant dans l'espace intervertébral correspondant à la hauteur d'un disque situé entre deux corps de vertèbre voisins. Ledit implant comprend: une partie avant partiellement en arc de cercle allant d'un côté à l'autre, des côtés au moins partiellement droits, et une extrémité arrière formant un arc de cercle d'un rayon différent. L'implant peut être fait de corticale, de composite osseux ou d'un matériau non osseux.

Abrégé anglais

An interbody spinal implant adapted for placement across an intervertebral
space formed across the height of a disc between two adjacent vertebral
bodies. The implant has a leading end that includes at least a portion of an
arc of a circle from side to side, and sides that are at least in part
straight or a trailing end having a radius of curvature of another circle from
side to side. The implant may be made cortical bone, a bone composite, or a
material other than bone.

Revendications

What is claimed is:
1. An interbody spinal implant made of cortical bone for insertion at least in
part into an implantation space formed across the height of a disc space
between adjacent vertebral bodies of a human spine, the vertebral bodies
having an anterior aspect and a posterior aspect and a depth
therebetween, said implant comprising:
a leading end for insertion first into the disc space and a trailing end
opposite said leading end, said implant having a length from said leading
end to said trailing end;
opposed upper and lower portions between said leading and trailing
ends adapted to be placed at least in part within and across the height of
the disc space to contact and support the adjacent vertebral bodies, said
upper and lower portions being non-arcuate along at least a portion of the
length of said implant; and
opposite sides between said upper portion and said lower portion,
and between said leading and trailing ends, said opposite sides defining a
width of said implant, at least one of said opposite sides being at least in
part straight along at least a portion of the length of said implant, said
leading end configured in the shape of approximately one half of a circle
from one of said opposite sides to another of said opposite sides, the circle
having a diameter generally equal to the width of said implant;
said implant being manufactured from a bone ring obtained from a
major long bone of a human having a medullary canal, said implant
including at least a portion of the medullary canal passing through said
upper and lower portions to form at least a portion of a passage adapted to
hold bone growth promoting material for permitting for the growth of bone
from vertebral body to vertebral body through said passage.
2. The implant of claim 1, wherein said implant has a maximum width
between said opposite sides that is greater than one-half of the width of
the adjacent vertebral bodies into which said implant is adapted to be
inserted.
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3. The implant of claim 1, wherein said implant has a maximum width
between said opposite sides that is less than one-half of the width of the
adjacent vertebral bodies into which said implant is adapted to be inserted.
4. The implant of claim 3, wherein said implant is adapted to be inserted side
by side a second of said implant into the disc space between the adjacent
vertebral bodies.
5. The implant of claim 1, wherein at least a portion of said leading end has
a
reduced height to facilitate insertion of said implant between the two
adjacent vertebral bodies.
6. The implant of claim 1, wherein said trailing end is adapted to conform
from side to side to at least a portion of the peripheral contour of at least
one of the anterior and posterior aspects of the vertebral bodies adjacent a
disc space into which said implant is inserted.
7. The implant of claim 1, wherein said passage is between said opposite
sides of said implant.
8. The implant of claim 1, wherein said passage intersects at least one of
said opposite sides.
9. The implant of claim 1, wherein said passage is between said leading and
trailing ends of said implant.
10. The implant of claim 1, wherein said implant has a mid-longitudinal axis
along the length, at least one of said opposite sides being at least in part
oriented generally parallel to the mid-longitudinal axis of said implant.
11. The implant of claim 1, wherein said opposite sides are at least in part
generally parallel one another.
12. The implant of claim 1, wherein at least a portion of said upper and lower
surfaces are in an angular relationship to each other from trailing end to
leading end for allowing angulation of the adjacent vertebral bodies
relative to each other.
13. The implant of claim 1, wherein said implant has a maximum length less
than and approximating the posterior to anterior depth of the vertebral
bodies.
14. The implant of claim 1, further comprising a bone engaging surface formed
on the exterior of at least said upper and lower portions for engaging the
adjacent vertebral bodies, said bone engaging surface including at least
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one of a protrusion, a ratchet, a spike, a spline, surface roughenings, and
knurling.
15. The implant of claim 1, wherein said implant includes at least two
members, each member having a leading portion, a trailing portion, a top,
a bottom, and at least one side, each member being adapted to be placed
side by side with another of said members, said leading portion of said
members forming said leading end of said implant when placed side by
side.
16. The implant of claim 15, wherein said implant includes two of said
members, each member being a mirror image of the other.
17. The implant of claim 15, wherein each member includes at least a portion
of said passage.
18. The implant of claim 1, wherein said implant comprises at least in part of
a
bone growth promoting material.
19. The implant of claim 18, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
20. The implant of claim 1, in combination with a bone growth promoting
material.
21. The implant of claim 20, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
22. The implant of claim 1, wherein said implant is treated with a bone growth
promoting substance.
23. The implant of claim 1, wherein said implant is at least in part
resorbable.
24. The implant of claim 1, in combination with a chemical substance adapted
to inhibit scar formation.
25. The implant of claim 1, in combination with an antimicrobial material.
26. The implant of claim 1, wherein at least a portion of said implant is
treated
to promote bone ingrowth between said implant and said adjacent
vertebral bodies.
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27. The implant of claim 1, further in combination with at least one spinal
fixation implant.
28. The implant of claim 1, wherein said trailing end is adapted to receive at
least one bone screw adapted to engage at least one vertebral body when
inserted through said implant.
29. The implant of claim 28, further comprising a lock for locking at least
one
bone screw to said implant.
30. The implant of claim 29, wherein said lock is made of one of cortical bone
and a bioresorbable material.
31. The implant of claim 28, wherein said screw is made of one of cortical
bone and a bioresorbable material.
32. An interbody spinal implant made of cortical bone for insertion at least
in
part into an implantation space formed across the height of a disc space
between adjacent vertebral bodies of a human spine, the vertebral bodies
having an anterior aspect and a posterior aspect and a depth
therebetween, said implant comprising:
a leading end for insertion first into the disc space and a trailing end
opposite said leading end, said implant having a length from said leading
end to said trailing end;
opposed upper and lower portions between said leading and trailing
ends adapted to be placed at least in part within and across the height of
the disc space to contact and support the adjacent vertebral bodies;
said implant having a maximum width that is greater than one-half
of the width of the adjacent vertebral bodies into which said implant is
adapted to be inserted, said leading end configured in the shape of
approximately one half of a first circle along the width of said implant, said
trailing end having a radius of curvature of a second circle along the width
of said implant, the second circle having a radius greater than the radius of
the first circle; and
said implant being manufactured from a bone ring obtained from a
major long bone of a human having a medullary canal, said implant
including at least a portion of the medullary canal passing through said
upper and lower portions to form a passage adapted to hold bone growth
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promoting material for permitting for the growth of bone from vertebral
body to vertebral body through said passage.
33. The implant of claim 32, wherein said leading end and said trailing end of
said implant intersect at diametrically opposite points of the implant.
34. The implant of claim 32, wherein said width of said implant is
approximately equal to the diameter of the first circle.
35. The implant of claim 32, wherein said implant has a height from said upper
portion to said lower portion, the height of said implant being less than the
maximum width of said implant.
36. The implant of claim 32, wherein at least a portion of said leading end
has
a reduced height to facilitate insertion of said implant between the two
adjacent vertebral bodies.
37. The implant of claim 32, wherein said trailing end is adapted to conform
from side to side to at least a portion of the peripheral contour of at least
one of the anterior and posterior aspects of the vertebral bodies adjacent a
disc space into which said implant is inserted.
38. The implant of claim 32, wherein said implant has a perimeter, said
passage being within said perimeter of said implant.
39. The implant of claim 32, wherein said implant has a perimeter, said
passage intersecting at least a portion of said perimeter.
40. The implant of claim 32, wherein said passage is between said leading
and trailing ends of said implant.
41. The implant of claim 32, further comprising opposite sides between said
leading end and said trailing end.
42. The implant of claim 41, wherein at least one of said opposite sides is at
least in part straight along at least a portion of the length of said implant.
43. The implant of claim 41, wherein said implant has a mid-longitudinal axis
along the length, at least one of said opposite sides being at least in part
oriented generally parallel to the mid-longitudinal axis of said implant.
44. The implant of claim 41, wherein said opposite sides are at least in part
generally parallel one another.
45. The implant of claim 32, wherein at least a portion of said upper and
lower
surfaces are in an angular relationship to each other from trailing end to
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leading end for allowing angulation of the adjacent vertebral bodies
relative to each other.
46. The implant of claim 32, wherein said implant has a maximum length less
than and approximating the posterior to anterior depth of the vertebral
bodies.
47. The implant of claim 32, further comprising a bone engaging surface
formed on the exterior of at least said upper and lower portions for
engaging the adjacent vertebral bodies, said bone engaging surface
including at least one of a protrusion, a ratchet, a spike, a spline, surface
roughenings, and knurling.
48. The implant of claim 32, wherein said implant includes at least two
members, each member having a leading portion, a trailing portion, a top,
a bottom, and at least one side, each member being adapted to be placed
side by side with another of said members, said leading portion of said
members forming said leading end of said implant when placed side by
side.
49. The implant of claim 47, wherein said implant includes two of said
members, each member being a mirror image of the other.
50. The implant of claim 48, wherein each member includes at least a portion
of said passage.
51. The implant of claim 32, wherein said implant comprises at least in part
of
a bone growth promoting material.
52. The implant of claim 51, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
53. The implant of claim 32, in combination with a bone growth promoting
material.
54. The implant of claim 53, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
55. The implant of claim 32, wherein said implant is treated with a bone
growth promoting substance.
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56. The implant of claim 32, wherein said implant is at least in part
resorbable.
57. The implant of claim 32, in combination with a chemical substance
adapted to inhibit scar formation.
58. The implant of claim 32, in combination with an antimicrobial material.
59. The implant of claim 32, wherein at least a portion of said implant is
treated to promote bone ingrowth between said implant and said adjacent
vertebral bodies.
60. The implant of claim 32, further in combination with at least one spinal
fixation implant.
61. The implant of claim 40, further comprising a curved transition between at
least one of said opposite sides and said trailing end, said curved
transition forming at least part of an arc of a circle.
62. The implant of claim 32, wherein said trailing end is adapted to receive
at
least one bone screw adapted to engage at least one vertebral body when
inserted through said implant.
63. The implant of claim 62, further comprising a lock for locking at least
one
bone screw to said implant.
64. The implant of claim 63, wherein said lock is made of one of cortical bone
and a bioresorbable material.
65. The implant of claim 62, wherein said screw is made of one of cortical
bone and a bioresorbable material.
66. An interbody spinal implant made of a bone composite material for
insertion at least in part into an implantation space formed across the
height of a disc space between adjacent vertebral bodies of a human
spine, the vertebral bodies having an anterior aspect and a posterior
aspect and a depth therebetween, said implant comprising:
a leading end for insertion first into the disc space and a trailing end
opposite said leading end, said implant having a length from said leading
end to said trailing end;
opposed upper and lower portions between said leading and trailing
ends adapted to be placed at least in part within and across the height of
the disc space to contact and support the adjacent vertebral bodies, said
upper and lower portions being non-arcuate along at least a portion of the
length of said implant;
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opposite sides between said upper portion and said lower portion,
and between said leading and trailing ends, said opposite sides defining a
width of said implant, at least one of said opposite sides being at least in
part straight along at least a portion of the length of said implant, said
leading end configured in the shape of approximately one half a circle from
one of said opposite sides to another of said opposite sides, the circle
having a diameter generally equal to the width of said implant; and
said implant being manufactured from a bone composite material,
said upper and lower portions of said implant including at least one
opening in communication with one another to form at least a portion of a
passage adapted to hold bone growth promoting material for permitting for
the growth of bone from vertebral body to vertebral body through said
passage.
67. The implant of claim 66, wherein said bone composite material includes at
least one of cortical bone fibers, bone filaments, bone particles and bone
dust.
68. The implant of claim 66, further comprising a binding material.
69. The implant of claim 59, wherein said binding material is at least one of
bioactive and bioresorbable.
70. The implant of claim 66, wherein said implant has a maximum width
between said opposite sides that is greater than one-half of the width of
the adjacent vertebral bodies into which said implant is adapted to be
inserted,
71. The implant of claim 66, wherein said implant has a maximum width
between said opposite sides that is less than one-half of the width of the
adjacent vertebral bodies into which said implant is adapted to be inserted.
72. The implant of claim 71, wherein said implant is adapted to be inserted
side by side a second of said implant into the disc space between the
adjacent vertebral bodies.
73. The implant of claim 66, wherein at least a portion of said leading end is
has a reduced height to facilitate insertion of said implant between the two
adjacent vertebral bodies.
74. The implant of claim 66, wherein said trailing end is adapted to conform
from side to side to at least a portion of the peripheral contour of at least
30

one of the anterior and posterior aspects of the vertebral bodies adjacent a
disc space into which said implant is inserted.
75. The implant of claim 66, wherein said passage is between said opposite
sides of said implant.
76. The implant of claim 66, wherein said passage intersects at least one of
said opposite sides of said implant.
77. The implant of claim 66, wherein said passage is between said leading
and trailing ends of said implant.
78. The implant of claim 66, wherein said implant has a mid-longitudinal axis,
at least one of said opposite sides being at least in part oriented generally
parallel to the mid-longitudinal axis of said implant.
79. The implant of claim 66, wherein said opposite sides are at least in part
generally parallel one another.
80. The implant of claim 66, wherein at least a portion of said upper and
lower
surfaces are in an angular relationship to each other from trailing end to
leading end for allowing angulation of the adjacent vertebral bodies
relative to each other.
81. The implant of claim 66, wherein said implant has a maximum length less
than and approximating the posterior to anterior depth of the vertebral
bodies.
82. The implant of claim 66, further comprising a bone engaging surface
formed on the exterior of at least said upper and lower portions for
engaging the adjacent vertebral bodies, said bone engaging surface
including at least one of a protrusion, a ratchet, a spike, a spline, surface
roughenings, and knurling.
83. The implant of claim 66, wherein said implant includes at least two
members, each member having a leading portion, a trailing portion, a top,
a bottom, and at least one side, each member being adapted to be placed
side by side with another of said members, said leading portion of said
members forming said leading end of said implant when placed side by
side.
84. The implant of claim 83, wherein said implant includes two of said
members, each member being a mirror image of the other.
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85. The implant of claim 83, wherein each member includes at least a portion
of said passage.
86. The implant of claim 66, wherein said implant comprises at least in part
of
a bone growth promoting material.
87. The implant of claim 86, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
88. The implant of claim 66, in combination with a bone growth promoting
material.
89. The implant of claim 88, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
90. The implant of claim 66, wherein said implant is treated with a bone
growth promoting substance.
91. The implant of claim 66, wherein said implant is at least in part
resorbable.
92. The implant of claim 66, in combination with a chemical substance
adapted to inhibit scar formation.
93. The implant of claim 66, in combination with an antimicrobial material.
94. The implant of claim 66, wherein at least a portion of said implant is
treated to promote bone ingrowth between said implant and said adjacent
vertebral bodies.
95. The implant of claim 66, further in combination with at least one spinal
fixationimplant.
96. The implant of claim 66, wherein said trailing end is adapted to receive
at
least one bone screw adapted to engage at least one vertebral body when
inserted through said implant.
97. The implant of claim 96, further comprising a lock for locking at least
one
bone screw to said implant.
98. The implant of claim 97, wherein said lock is made of one of cortical bone
and a bioresorbable material.
99. The implant of claim 96, wherein said screw is made of one of cortical
bone and a bioresorbable material.
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100. An interbody spinal implant made of a bone composite material for
insertion at least in part into an implantation space formed across the
height of a disc space between adjacent vertebral bodies of a human
spine, the vertebral bodies having an anterior aspect and a posterior
aspect and a depth therebetween, said implant comprising:
a leading end for insertion first into the disc space and a trailing end
opposite said leading end, said implant having a length from said leading
end to said trailing end;
opposed upper and lower portions between said leading and trailing
ends adapted to be placed at least in part within and across the height of
the disc space to contact and support the adjacent vertebral bodies;
said implant having a maximum width that is greater than one-half
of the width of the adjacent vertebral bodies into which said implant is
adapted to be inserted, said leading end configured in the shape of
approximately one half of a first circle along the width of said implant, said
trailing end having a radius of curvature of a second circle along the width
of said implant, the second circle having a radius greater than the radius of
the first circle; and
said implant being manufactured from a bone composite material,
said upper and lower portions of said implant including at least one
opening in communication with one another to form a passage adapted to
hold bone growth promoting material for permitting for the growth of bone
from vertebral body to vertebral body through said passage.
101. The implant of claim 100, wherein said bone composite material includes
at least one of cortical bone fibers, bone filaments, bone particles and
bone dust.
102. The implant of claim 100, further comprising a binding material.
103. The implant of claim 102, wherein said binding material is at least one
of
bioactive and bioresorbable.
104. The implant of claim 100, wherein said leading end and said trailing end
of
said implant intersect at diametrically opposite points of the implant.
105. The implant of claim 100, wherein said width of said implant is
approximately equal to the diameter of the first circle.
33

106. The implant of claim 100, wherein said implant has a height from said
upper portion to said lower portion the height of said implant is less than
the maximum width of said implant.
107. The implant of claim 100, wherein at least a portion of said leading end
has a reduced height to facilitate insertion of said implant between the two
adjacent vertebral bodies.
108. The implant of claim 100, wherein said trailing end is adapted to conform
from side to side to at least a portion of the peripheral contour of at least
one of the anterior and posterior aspects of the vertebral bodies adjacent a
disc space into which said implant is inserted.
109. The implant of claim 100, wherein implant has a perimeter and said
passage is at least in part with said perimeter of said implant.
110. The implant of claim 100, wherein said implant has a perimeter, said
passage intersecting at least a portion of said perimeter of said implant.
111. The implant of claim 100, wherein said passage is between said leading
and trailing ends of said implant.
112. The implant of claim 100, further comprising opposite sides between said
leading end and said trailing end.
113. The implant of claim 112, wherein at least one of said opposite sides is
at
least in part straight along at least a portion of the length of said implant.
114. The implant of claim 112, wherein said implant has a mid-longitudinal
axis
along the length, at least one of said opposite sides being at least in part
oriented generally parallel to the mid-longitudinal axis of said implant.
115. The implant of claim 112, wherein said opposite sides are at least in
part
generally parallel one another.
116. The implant of claim 100, wherein at least a portion of said upper and
lower surfaces are in an angular relationship to each other from trailing
end to leading end for allowing angulation of the adjacent vertebral bodies
relative to each other.
117. The implant of claim 100, wherein said implant has a maximum length less
than and approximating the posterior to anterior depth of the vertebral
bodies.
118. The implant of claim 100, further comprising a bone engaging surface
formed on the exterior of at least said upper and lower portions for
34

engaging the adjacent vertebral bodies, said bone engaging surface
including at least one of a protrusion, a ratchet, a spike, a spline, surface
roughenings, and knurling.
119. The implant of claim 100, wherein said implant includes at least two
members, each member having a leading portion, a trailing portion, a top,
a bottom, and at least one side, each member being adapted to be placed
side by side with another of said members, said leading portion of said
members forming said leading end of said implant when placed side by
side.
120. The implant of claim 119, wherein said implant includes two of said
members, each member being a mirror image of the other.
121. The implant of claim 119, wherein each member includes at least a portion
of said passage.
122. The implant of claim 100, wherein said implant comprises at least in part
of a bone growth promoting material.
123. The implant of claim 122, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
124. The implant of claim 100, in combination with a bone growth promoting
material.
125. The implant of claim 124, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
126. The implant of claim 100, wherein said implant is treated with a bone
growth promoting substance.
127. The implant of claim 100, wherein said implant is at least in part
resorbable.
128. The implant of claim 100, in combination with a chemical substance
adapted to inhibit scar formation.
129. The implant of claim 100, in combination with an antimicrobial material.
35

130. The implant of claim 100, wherein at least a portion of said implant is
treated to promote bone ingrowth between said implant and said adjacent
vertebral bodies.
131. The implant of claim 100, further in combination with at least one spinal
fixation implant.
132. The implant of claim 111, further comprising a curved transition between
at
least one of said opposite sides and said trailing end, said curved
transition forming at least part of an arc of a circle.
133. The implant of claim 100, wherein said trailing end is adapted to receive
at
least one bone screw adapted to engage at least one vertebral body when
inserted through said implant.
134. The implant of claim 133, further comprising a lock for locking at least
one
bone screw to said implant.
135. The implant of claim 134, wherein said lock is made of one of cortical
bone
and a bioresorbable material.
136. The implant of claim 133, wherein said screw is made of one of cortical
bone and a bioresorbable material.
137. An artificial interbody spinal implant for insertion at least in part
into an
implantation space formed across the height of a disc space between
adjacent vertebral bodies of a human spine, the vertebral bodies having an
anterior aspect and a posterior aspect and a depth therebetween, said
implant comprising:
a leading end for insertion first into the disc space and a trailing end
opposite said leading end, said implant having a length from said leading
end to said trailing end;
opposed upper and lower portions between said leading and trailing
ends adapted to be placed at least in part within and across the height of
the disc space to contact and support the adjacent vertebral bodies, said
upper and lower portions defining a height of said implant, said upper and
lower portions being non-arcuate along at least a portion of the length of
said implant; and
opposite sides between said upper portion and said lower portion,
and between said leading and trailing ends, said opposite sides defining a
width of said implant, at least one of said opposite sides being at least in
36

part straight along at least a portion of the length of said implant, said
leading end configured in the shape of approximately one half of a circle
from one of said opposite sides to another one of said opposite sides, the
circle having a diameter generally equal to the width of said implant, the
width of said implant being greater than the height of said implant;
said implant being manufactured from a material other than bone,
said upper and lower portions of said implant including at least one
opening in communication with one another and adapted to hold bone
growth promoting material for permitting for the growth of bone from
vertebral body to vertebral body through said implant.
138. The implant of claim 137, wherein said implant has a maximum width
between said opposite sides that is greater than one-half of the width of
the adjacent vertebral bodies into which said implant is adapted to be
inserted.
139. The implant of claim 137, wherein said implant has a maximum width
between said opposite sides that is less than one-half of the width of the
adjacent vertebral bodies into which said implant is adapted to be inserted.
140. The implant of claim 139, wherein said implant is adapted to be inserted
side by side a second of said implant into the disc space between the
adjacent vertebral bodies.
141. The implant of claim 137, wherein at least a portion of said leading end
has a reduced height to facilitate insertion of said implant between the two
adjacent vertebral bodies.
142. The implant of claim 137, wherein said trailing end is adapted to conform
from side to side to at least a portion of the peripheral contour of at least
one of the anterior and posterior aspects of the vertebral bodies adjacent a
disc space into which said implant is inserted.
143. The implant of claim 137, wherein said trailing end has a radius of
curvature of a second circle from side to side.
144. The implant of claim 143, wherein the radius of curvature said trailing
end
is greater than the radius of curvature of the leading end of said implant.
145. The implant of claim 137, wherein said at least one opening is between
said opposite sides of said implant.
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146. The implant of claim 137, wherein said at least one opening intersects at
least one of said opposite sides.
147. The implant of claim 137, wherein said at least one opening is between
said leading and trailing ends of said implant.
148. The implant of claim 137, wherein said implant has a mid-longitudinal
axis
along the length, at least one of said opposite sides being at least in part
oriented generally parallel to the mid-longitudinal axis of said implant.
149. The implant of claim 137, wherein said opposite sides are at least in
part
generally parallel one another.
150. The implant of claim 137, wherein at least a portion of said upper and
lower surfaces are in an angular relationship to each other from trailing
end to leading end for allowing angulation of the adjacent vertebral bodies
relative to each other.
151. The implant of claim 137, wherein said implant has a maximum length less
than and approximating the posterior to anterior depth of the vertebral
bodies.
152. The implant of claim 137, further comprising a bone engaging surface
formed on the exterior of at least said upper and lower portions for
engaging the adjacent vertebral bodies, said bone engaging surface
including at least one of a protrusion, a ratchet, a spike, a spline, surface
roughenings, and knurling.
153. The implant of claim 137, wherein said implant includes at least two
members, each member having a leading portion, a trailing portion, a top,
a bottom, and at least one side, each member being adapted to be placed
side by side with another of said members, said leading portion of said
members forming said leading end of said implant when placed side by
side.
154. The implant of claim 153, wherein said implant includes two of said
members, each member being a mirror image of the other.
155. The implant of claim 153, wherein each member includes at least a portion
of said at least one opening.
156. The implant of claim 137, in combination with a bone growth promoting
material.
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157. The implant of claim 156, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
158. The implant of claim 137, wherein said implant is treated with a bone
growth promoting substance.
159. The implant of claim 137, wherein said implant is at least in part
resorbable.
160. The implant of claim 137, in combination with a chemical substance
adapted to inhibit scar formation.
161. The implant of claim 137, in combination with an antimicrobial material.
162. The implant of claim 137, wherein at least a portion of said implant is
treated to promote bone ingrowth between said implant and said adjacent
vertebral bodies.
163. The implant of claim 137, in combination with at least one spinal
fixation
implant.
164. The implant of claim 137, wherein said trailing end is adapted to receive
at
least one bone screw adapted to engage at least one vertebral body when
inserted through said implant.
165. The implant of claim 164, further comprising a lock for locking at least
one
bone screw to said implant.
166. An artificial interbody spinal implant for insertion at least in part
into an
implantation space formed across the height of a disc space between
adjacent vertebral bodies of a human spine, the vertebral bodies having an
anterior aspect and a posterior aspect and a depth therebetween, said
implant comprising:
a leading end for insertion first into the disc space and a trailing end
opposite said leading end, said implant having a length from said leading
end to said trailing end;
opposed upper and lower portions between said leading and trailing
ends adapted to be placed at least in part within and across the height of
the disc space to contact and support the adjacent vertebral bodies;
said implant having a maximum width that is greater than one-half
of the width of the adjacent vertebral bodies into which said implant is
39

adapted to be inserted, said leading end configured in the shape of
approximately one half of a first circle along the width of said implant, said
trailing end having a radius of curvature of a second circle along the width
of said implant, the second circle having a radius greater than the radius of
the first circle; and
said implant being manufactured from a material other than bone,
said upper and lower portions of said implant including at least one
opening in communication with one another and adapted to hold bone
growth promoting material for permitting for the growth of bone from
vertebral body to vertebral body through said implant.
167. The implant of claim 166, wherein said leading end and said trailing end
of
said implant intersect at diametrically opposite points of said implant.
168. The implant of claim 166, wherein said width of said implant is
approximately equal to the diameter of the first circle.
169. The implant of claim 166, wherein said implant has a height from said
upper portion to said lower portion, the height of said implant being less
than the maximum width of said implant.
170. The implant of claim 166, wherein at least a portion of said leading end
has a reduced height to facilitate insertion of said implant between the two
adjacent vertebral bodies.
171. The implant of claim 166, wherein said trailing end is adapted to conform
from side to side to at least a portion of the peripheral contour of the
anterior aspect of the vertebral bodies adjacent a disc space into which
said implant is inserted.
172. The implant of claim 166, wherein said implant has a perimeter, said at
least one opening being within said perimeter of said implant.
173. The implant of claim 166, wherein said implant has a perimeter, said at
least one opening intersecting at least a portion of said perimeter of said
implant.
174. The implant of claim 166, wherein said at least one opening is between
said leading and trailing ends of said implant.
175. The implant of claim 166, further comprising opposite sides between said
leading end and said trailing end.
40

176. The implant of claim 175, wherein at least one of said opposite sides is
at
least in part straight along at least a portion of the length of said implant.
177. The implant of claim 175, wherein said implant has a mid-longitudinal
axis
along the length, at least one of said opposite sides being at least in part
oriented generally parallel to the mid-longitudinal axis of said implant.
178. The implant of claim 175, wherein said opposite sides are at least in
part
generally parallel one another.
179. The implant of claim 166, wherein at least a portion of said upper and
lower surfaces are in an angular relationship to each other from trailing
end to leading end for allowing angulation of the adjacent vertebral bodies
relative to each other.
180. The implant of claim 166, wherein said implant has a maximum length less
than and approximating the posterior to anterior depth of the vertebral
bodies.
181. The implant of claim 166, further comprising a bone engaging surface
formed on the exterior of at least said upper and lower portions for
engaging the adjacent vertebral bodies, said bone engaging surface
including at least one of a protrusion, a ratchet, a spike, a spline, surface
roughenings, and knurling.
182. The implant of claim 166, wherein said implant includes at least two
members, each member having a leading portion, a trailing portion, a top,
a bottom, and at least one side, each member being adapted to be placed
side by side with another of said members, said leading portion of said
members forming said leading end of said implant when placed side by
side.
183. The implant of claim 182, wherein said implant includes two of said
members, each member being a mirror image of the other.
184. The implant of claim 182, wherein each member includes at least a portion
of said at least one opening.
185. The implant of claim 166, in combination with a bone growth promoting
material.
186. The implant of claim 185, wherein said bone growth promoting material is
selected from one of bone, bone derived products, demineralized bone
41

matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
protein, hydroxyapatite, and genes coding for the production of bone.
187. The implant of claim 166, wherein said implant is treated with a bone
growth promoting substance.
188. The implant of claim 166, wherein said implant is at least in part
resorbable.
189. The implant of claim 166, in combination with a chemical substance
adapted to inhibit scar formation.
190. The implant of claim 166, in combination with an antimicrobial material.
191. The implant of claim 166, wherein at least a portion of said implant is
treated to promote bone ingrowth between said implant and said adjacent
vertebral bodies.
192. The implant of claim 166, in combination with at least one spinal
fixation
implant.
193. The implant of claim 175, further comprising a curved transition between
at
least one of said opposite sides and said trailing end, said curved
transition forming at least part of an arc of a circle.
194. The implant of claim 16630, wherein said trailing end is adapted to
receive
at least one bone screw adapted to engage at least one vertebral body
when inserted through said implant.
195. The implant of claim 194, further comprising a lock for locking at least
one
bone screw to said implant.
42

Description

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CONTOURED SPINAL FUSION IMPLANTS
Related applications
This application claims priority to provisional application no. 60/281,187,
filed April 3, 2001, and provisional application no. 60/281,112, filed April
2, 2001,
both of which are incorporated by reference~herein.
Field of the Invention
The present invention relates generally to interbody spinal implants
preferably adapted for placement into an implantation space created across the
height of a disc space between two adjacent vertebral bodies for the purpose
of
correcting spinal disease at that interspace. The implants are adapted such
that
fusion occurs at least in part through the implants. The implant may be made
cortical bone, a bone composite, or a material other than bone.
Description of the Related Art
Implants for placement between adjacent vertebral bodies in the spine
come in a variety of shapes and sizes and are made of a variety of materials.
Such implants for use in human spinal surgery include implants made of bone or
selected inert materials, such as titanium, that have a structure designed to
promote fusion of the adjacent vertebral bodies by allowing bone to grow
through
the implant to thereby fuse the adjacent vertebral bodies.
Implants made of bone and utilized in interbody spinal surgery are often
formed from a portion of the diaphysis. The diaphysis is the shaft of a major
long
bone between the epiphyses, the ends of the bone forming the joints.
A diaphyseal ring is formed by making two spaced apart cuts
approximately perpendicular to the long axis of the diaphyseal portion of a
major
long bone with the medullary canal forming an opening through the ring. Such
rings are generally harvested from femurs for use in the lumbar spine. Other
bones from the arm or leg or other part of the human skeleton may be useful in
various regions of the spine.
The cuts are generally spaced apart so as to form a ring of bone having a
height corresponding to the restored disc space or slightly greater.
Diaphyseal
ring bone grafts are placed into the spine within and across the height of the
space previously occupied by a spinal disc between adjacent vertebral bodies
to

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achieve interbody fusion of those vertebral bodies through the disc space. The
diaphyseal ring bone graft is incorporated into the bony fusion over time.
Interbody spinal fusion with diaphyseal bone rings, however, has had
limited success in the past. While all the causes for failure may not yet be
appreciated, it is nevertheless believed that a failure to gain congruity at
the
interfaces of the bone ring implant to the adjacent vertebral bodies, and a
failure
to achieve stability of the bone ring implant, may be two of the more
significant
factors subject to the surgeon's control contributing to such failures.
At the time of surgery, where fusion is intended to occur between adjacent
vertebral bodies of a patient's spine; the surgeon typically prepares an
opening at
the site of the intended fusion by removing some or all of the disc material
that
exists between the adjacent vertebral bodies to be fused. Because the
outermost
layers of bone of the vertebral end plate are relatively inert to new bone
growth,
the surgeon must work on the end plate to remove at least the outermost cell
layers of bone to gain access to the blood-rich, vascular bone tissue within
the
vertebral body. In this manner, the vertebrae are prepared in a way that
encourages new bone to grow into or through an implant that is placed between
the vertebral bodies.
Present methods of forming this space between adjacent vertebral bodies
generally include the use of one or more of the following: hand held biting
and
grasping instruments known as rongeurs; drills and drill guides; rotating
burrs
driven by a motor; osteotomes and chisels, and a double wheel cutter or
vertebral
interspace preparation device. In particular, the double wheel cutter or
vertebral
interspace preparation device, as disclosed by Michelson in WO 99/63891,
incorporated herein by reference, is adapted for linear insertion, i.e.,
insertion
along a single axis, and without the need to substantially move the device
from
side to side within the disc space along a second axis. In such a preferred
embodiment, the device has at its working end an abrading element having a
width generally corresponding to the width of the implant to be implanted.
There is a desire to improve congruity at the interfaces of the implant to
the adjacent vertebral bodies, and to achieve stability of the implant.
Therefore it
is advantageous for the contour of the implants to closely match the
implantation
space formed between and at least in part into the adjacent vertebral bodies
to

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allow a more uniform load transfer across the implant between the vertebral
bodies.
Interbody spinal implants that are entirely or almost entirely made of
cortical bone or a bone composite material offer the advantages of that
material
including an appropriate modulus of elasticity and strength for the prescribed
use,
the capacity to be bioactive, including being osteoconductive, osteoinductive,
osteogenic, and to more generally provide a good substrate for the formation
of
new bone as fusion occurs. Further, by being bioabsorable the bone material is
replaced by the patient's own bone over time, thereby preventing stress
shielding
and leading to the eventual elimination of any foreign body from the
implantation
site.As it is desirable to take advantage of all these benefits, there exists
a need
for an improved interbody spinal fusion implant made of bone, a bone composite
material, or a material other than bone having a configuration that provides
for an
improved congruity of the implant to the vertebral bodies and improved implant
stability.
SUMMARY OF THE INVENTION
In accordance with the purposes of the present invention, as embodied
and broadly described herein, an interbody spinal fusion implant made of
cortical
bone is provided for insertion at least in part into an implantation space
formed
across the height of a disc space between adjacent vertebral bodies of a human
spine. The implant includes a leading end for insertion first into the disc
space
and a trailing end opposite the leading end. The implant has a length from the
leading end to the trailing end. The leading end is configured in the shape of
half
a circle from side to side. The implant also includes opposed upper and lower
portions between the leading and trailing ends that are adapted to be placed
within the disc space to contact and support the adjacent vertebral bodies.
The
upper and lower portions are non-arcuate along at least a portion of the
length of
the implant. The implant also includes opposite sides between the upper
portion
and lower portion, and between the leading and trailing ends. At least one of
the
opposite sides is at least in part straight along at least a portion of the
length of
the implant.
In accordance with the purposes of the present invention, as embodied
and broadly described herein, an interbody spinal fusion implant made of
cortical
bone is provided for insertion at least in part into an implantation space
formed

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across the height of a disc space between adjacent vertebral bodies of a human
spine. The implant includes a leading end for insertion first into the disc
space
and a trailing end opposite the leading end. The implant has a length from the
leading end to the trailing end. The leading end is configured from side to
side in
the shape of approximately one half of a first circle. The trailing end has a
radius
of curvature of a second circle from side to side. The second circle has a
radius
greater than the radius of the first circle. The implant also includes opposed
upper and lower portions between the leading and trailing ends that are
adapted
to be placed within the disc space to contact and support the adjacent
vertebral
bodies. The implant has a maximum width that is greater than one-half of the
width of the adjacent vertebral bodies into which the implant is adapted to be
inserted.
The implants mentioned above are preferably manufactured from a bone
ring obtained from a major long bone of a human having a medullary canal. The
implant includes at least a portion of the medullary canal passing through the
upper and lower portions to form a passage adapted to hold bone growth
promoting material for permitting for the growth of bone from vertebral body
to
vertebral body through the passage. Alternatively, the implants mentioned
above
may be manufactured from a bone composite material.
In accordance with the purposes of the present invention, as embodied
and broadly described herein, an artificial interbody spinal fusion implant
made of
a material other than bone is provided for insertion at least in part into an
implantation space formed across the height of a disc space between adjacent
vertebral bodies of a human spine. The implant includes a leading end for
insertion first into the disc space and a trailing end opposite the leading
end. The
implant has a length from the leading end to the trailing end. The leading end
is
configured in the shape of approximately one half of a circle from side to
side.
The implant also includes opposed upper and lower portions between the leading
and trailing ends that are adapted to be placed within the disc space to
contact
and support the adjacent vertebral bodies. The upper and lower portions are
non-arcuate along at least a portion of the length of the implant. The upper
and
lower portions include at least one opening in communication with one another
and adapted to hold bone growth promoting material for permitting for the
growth
of bone from vertebral body to vertebral body through the implant. The implant

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also includes opposite sides between the upper portion and lower portion, and
between the leading and trailing ends. At least one of the opposite sides is
at
least in part straight along at least a portion of the length of the implant.
In accordance with the purposes of the present invention, as embodied
and broadly described herein, an artificial interbody spinal fusion implant
made of
a material other than bone is provided for insertion at least in part into an
implantation space formed across the height of a disc space between adjacent
vertebral bodies of a human spine. The implant includes a leading end for
insertion first into the disc space and a trailing end opposite the leading
end. The
implant has a length from the leading end to the trailing end. The leading end
is
configured from side to side in the shape of approximately one half of a first
circle. The trailing end has a radius of curvature of a second circle from
side to
side. The second circle has a radius greater than the radius of the first
circle.
The implant also includes opposed upper and lower portions between the leading
and trailing ends that are adapted to be placed within the disc space to
contact
and support the adjacent vertebral bodies. The upper and lower portions
include
at least one opening in communication with one another. and adapted to hold
bone growth promoting material for permitting for the growth of bone from
vertebral body to vertebral body through the implant. The implant has a
maximum width that is greater than one-half of the width of the adjacent
vertebral
bodies into which the implant is adapted to be inserted.
Additional objects and advantages of the invention will be set forth in part
in the description which follows, and in part will be obvious from
the.description,
or may be learned by practice of the invention. The objects and advantages of
the invention will be realized and attained by means of the elements and
combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a top plan view of a vertebral body in the lumbar spine with an
implantation space formed to receive a spinal implant having a radius of
curvature at the leading end that is less than the radius of curvature of the
trailing
end of the anterior aspect of the vertebral body between the sides of the
implantation space.

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Fig. 2 is a side elevation view of two adjacent vertebral bodies in the
lumbar spine with the implantation space of Fig. 1 formed across the height of
the
spinal disc and into the adjacent vertebral bodies.
Fig. 3 is a side perspective view of the implantation space of Fig. 1.
Fig. 4 is a top plan view of a vertebral body in the cervical spine with an
implantation space formed to receive a spinal implant having a radius of
curvature at the leading end that is less than the radius of curvature of the
trailing
end of the anterior aspect of the vertebral body.
Fig. 5 is a side elevation view of two adjacent vertebral bodies in the
cervical spine with the implantation space of Fig. 4 formed across the height
of
the spinal disc and into the adjacent vertebral bodies.
Fig. 6 is a side perspective view of the implantation space of Fig. 4.
Fig. 7 is a top plan view of a vertebral body in the lumbar spine and a
preferred embodiment of an implant in accordance with the present invention
installed into the implantation space of Fig.1.
Fig. 8 is a side elevation view of two adjacent vertebral bodies with the
implant of Fig. 7 installed into the implantation space of Fig. 1 formed
across the
height of the spinal disc and into the adjacent vertebral bodies.
Fig. 9 is a top plan view of the implant of Fig. 7.
Fig. 10 is a side elevation view of the implant of Fig. 7.
Fig. 11 is a leading end view of the implant of Fig. 7.
Fig. 12 is a trailing end view of the implant of Fig. 7.
Fig. 13 is a top plan view of a vertebral body in the lumbar spine and
another preferred embodiment of an implant in accordance with the present
invention installed into the implantation space of Fig.1.
Fig. 14 is a side elevation view of two adjacent vertebral bodies with the
implant of Fig. 13 installed into the implantation space of Fig. 1 formed
across the
height of the spinal disc and into the adjacent vertebral bodies.
Fig. 15 is a top plan view of the implant of Fig. 13.
Fig. 16 is a side elevation view of the implant of Fig. 13.
Fig. 17 is a leading end view of the implant of Fig. 13.
Fig. 18 is a trailing end view of the implant of Fig. 13.
Fig. 19 is a top plan view of another preferred embodiment of an implant in
accordance with the present invention for use in the implantation space of
Fig. 4.
6

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Fig. 20 is a top plan view of another preferred embodiment of an implant in
accordance with the present invention for use in the implantation space of
Fig. 4.
Fig. 21 is a rear perspective view of anofiher preferred embodiment of an
implant in accordance with another preferred embodiment of the present
invention having two members that are preferably mirror images of one another.
Fig. 22 is a top plan view of one of the members of the implant of Fig. 21.
Fig. 23 is an interior side elevation view of one of the members of the
implant of Fig. 21.
Fig. 24 is an exterior side elevation view of one of the members of the
implant of Fig. 21.
Fig. 25 is a leading end view of one of the members of the implant of Fig.
21.
Fig. 26 is a trailing end view of one of the members of the implant of Fig.
21.
Fig. 27 is a rear perspective view of another preferred embodiment of an
implant in accordance with another preferred embodiment of the present
invention having two members that are preferably mirror images of one another.
Fig. 28 is a top plan view of one of the members of the implant of Fig. 27.
Fig. 29 is an interior side elevation view of one of the members of the
implant of Fig. 27.
Fig. 30 is an exterior side elevation view of one of the members of the
implant of Fig. 27.
Fig. 31 is a leading end view of one of the members of the implant of Fig.
27.
Fig. 32 is a trailing end view of one of the members of the implant of Fig.
27.
Fig. 33 is a top plan view of another preferred embodiment of an implant in
accordance with the present invention and a second implant that is a mirror
image thereof illustrated in dashed line, both implants being shown implanted
from an anterior approach to the spine in a vertebral body illustrated in
dashed
line.
Fig. 34 is a top plan view of another preferred embodiment of an implant in
accordance with the present invention and a second implant that is a mirror
image thereof illustrated in dashed line, both implants being shown implanted
7 _

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from an anterior approach to the spine in a vertebral body illustrated in
dashed
line.
Fig. 35 is a top plan view of another preferred embodiment of an implant in
accordance with the present invention and a second implant that is a mirror
image thereof illustrated in dashed line, both implants being shown implanted
from a posterior approach to the spine in a vertebral body illustrated in
dashed
fine.
Fig. 36 is a top plan view of another preferred embodiment of an implant in
accordance with the present invention with bone engaging screws.
Fig. 37 is a side elevation view of the implant of Fig. 36.
Fig. 38 is a leading end view of the implant of Fig. 36.
Fig. 39 is a trailing end view of the implant of Fig. 36 with the bone
engaging screws and lock installed.
Fig. 40 is a trailing end view of the implant of Fig. 39 without the bone
engaging screws and lock installed.
Fig. 41 is a partial cross sectional side view of a preferred embodiment of
a bone screw lock in accordance with the present invention for use with the
implant of Fig. 36.
Fig. 42 is a cross sectional side view of another preferred embodiment of a
bone screw lock in accordance with the present invention.
Fig. 43 is a top plan view of another preferred embodiment of an implant in
accordance with the present invention with bone engaging screws.
Fig. 44 is a side elevation view of the implant of Fig. 43.
Fig. 45 is a leading end view of the implant of Fig. 43.
Fig. 46 is a trailing end view of the implant of Fig. 43 with the bone
engaging screws and lock installed.
Fig. 47 is a trailing end view of the implanfi of Fig. 46 without the bone
engaging screws and lock installed.
Fig. 48 is a partial cross sectional side view of a preferred embodiment of
a bone screw lock in accordance with the presenfi invention for use with the
implant of Fig. 43.
Fig. 49 is a cross sectional side view of another preferred embodiment of a
bone screw lock in accordance with the present invention.

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DETAILED DESCRIPTION OF THE INVENTION
The following description is intended to be representative only and not
limiting and many variations can be anticipated according to these teachings,
which are included within the scope of this inventive teaching. Reference will
now be made in detail to the preferred embodiments of this invention, examples
of which are illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to refer to the
same or like parts.
Figs. 1-3 show an implantation space 50 formed across the height of the
space occupied by a spinal disc D and into vertebral bodies V in the lumbar
spine. Implantation space 50 is preferably formed with the apparatus and
method disclosed by Michelson in U.S. Patent No. 6,083,228, and WO 99/63891,
the disclosures of which are both incorporated herein by reference. The
instruments and method are not the subject matter of this application. It is
understood that the preparation of the implantation space shown therein are a
preferred instrument and method of preparing the implantation spaces and that
any method and instrumentation suitable for the purpose may be utilized to
prepare the desired implantation space.
Implantation space 50 is preferably formed in the endplate region ER in ,
the subchondral bone of the vertebral body V. Implantation space 50 preferably
is formed to have a leading edge 52 with a shape from side to side of
approximately one-half of a first circle A. The trailing portion 54 of
implantation
space 50 preferably includes at least a portion of the anterior aspect of the
vertebral body having a radius of curvature of a second circle B from side to
side.
Preferably the radius of circle A is less than the radius of circle B.
Implantation
space 50 may further include side edges 56, 58. Side edges 56, 58 preferably
include at least a straight portion, may be parallel to one another along
lines P
and form a curved transition with leading edge 52.
Figs. 4-6 show an implantation space 60 formed across the height of the
space occupied by a spinal disc D and into vertebral bodies V in the cervical
spine. Implantation space 60 preferably is formed to have a leading edge 62
with
a shape from side to side of approximately one half of a first circle A. The
trailing
portion of implantation space 60 preferably includes at least a portion of the
anterior aspect of the vertebral body having a radius of curvature of a second

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circle C from side to side. Preferably the radius of circle A is less than the
radius
of circle C. Implantation space 60, however, preferably does not have straight
side edges like implantation space 50 because the anterior to posterior depth
of
cervical vertebral bodies is less than the anterior to posterior depth of
lumbar
vertebral bodies. Thus, the radius of circle C is smaller in the cervical
spine than
the radius of circle B in the lumbar spine.
Figs. 7-12 show an implant 100A in accordance with a preferred
embodiment of the present invention. Implant 100A is preferably manufactured
from a bone ring obtained from a major long bone of a human. Implant 100A has
a leading end 102A for insertion first into the disc space between two
adjacent
vertebral bodies and a trailing end 104A opposite leading end 102A, and
opposite
sides 110A, 112A therebetween. Leading end 102A is preferably configured to
match the contour of leading edge 52 of implantation space 50 and trailing end
104A is preferably configured to conform to the contour of the anterior aspect
of
the vertebral body at trailing portion 54 of implantation space 50. Sides
110A,
112A are generally planar and preferably correspond to the configuration of
side
edges 56, 58 of implantation space 50.
In a preferred embodiment of the present invention, leading end 102A,
trailing end 104A, and opposite sides 110A, 112A are machined to have various
configurations. Leading end 102A is preferably machined to have a shape of
approximately half a first circle~from side to side. Where the iri~plantation
space
is prepared into the vertebral bodies to have a lip or ridge that is at least
in part
curved, leading end 102A may be adapted to abut at least that portion of the
implantation space.
One or both of sides 110A, 112A may also be formed to be at least in part
oriented generally parallel to the mid-longitudinal axis of implant 100A
and/or to
each other. Further, leading end 102A may be tapered to facilitate insertion
of
implant 100A between the two adjacent vertebral bodies.
Trailing end 104A preferably forms an arc of a second circle from side to
side having a radius greater than the radius of the first circle associated
with
leading end 102A. Preferably, at least a portion of trailing end 104A is
adapted to
conform to at least a portion of the peripheral contour of the anterior aspect
of the
vertebral bodies adjacent the disc space into which the implant is adapted to
be
inserted, though the invention is not so limited.
to

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Fig. 12 shows that implant 100A preferably has a driver opening 116A at
trailing end 104A for cooperatively engaging an instrument for installing
implant
100A into the implantation space. Driver opening 116A is preferably configured
for threaded engagement with an insertion instrument.
Figs. 8, 10, and 11 show at least a portion of upper and lower surfaces
106A, 108A in an angular relationship to each other from trailing end 104A to
leading end 102A for allowing for angulation of the adjacent vertebral bodies
relative to each other. Preferably, upper and lower surfaces 106A, 108A are
non-
arcuate in a direction along the mid-longitudinal axis of implant 100A.
Implant
100A preferably has a maximum height that is less than the maximum width of
the implant.
As shown in Fig. 9, upper and lower surfaces 106A, 108A preferably have
a passage 114A passing therethrough between leading and trailing ends 102A,
104A, respectively, and opposite sides 11 OA, 112A. Passage 114A is preferably
adapted to hold bone growth promoting material to permit for the growth of
bone
from vertebral body to vertebral body through passage 114A. In addition to
passage 114A, upper and lower surfaces 106A, 108A may include at least one
opening in communication with one another to permit for the growth of bone
from
vertebral body to vertebral body through implant 100A, though the invention is
not
so limited. Upper and lower surfaces 106A, 108A may also be porous and may
include a bone ingrowth surface.
As shown in Fig. 9, the implants described herein may include a bone-
engaging surface 118A such as knurling for example. Bone engaging surface
118A is configured to engage the bone of the adjacent vertebral bodies to
maintain implant 100A within the adjacent vertebral bodies after implantation.
Other preferred embodiments of bone-engaging surfaces may include the
surfaces of the implant being roughened, ratcheted, splined, or may include at
least one protrusion to penetrably engage the bone of the vertebral bodies. By
way of example only, the implants of the present invention may include the
surface configuration taught by Michelson in U.S. Patent Application No.
09/457,228, entitled "Spinal Implant Surface Configuration," the disclosure of
which is incorporated by reference herein.
Implant 100A is preferably, but need not be manufactured from a
diaphyseal bone ring. The diaphyseal bone ring is preferably obtained from a
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major long bone of the human skeleton. The bone ring is formed by making two
spaced aparfi cuts approximately perpendicular to the long axis of the
diaphyseal
portion of the major long bone with a portion of the medullary canal forming
an
opening through the ring. Such rings are generally harvested from femurs for
use
in the lumbar spine. Other bones from the arm or leg or other part of the
human
skeleton may be useful in various regions of the spine. The cuts may be made
into the long bone generally perpendicular to or at other angles transverse to
the
long axis of the diaphyseal bone to form the bone ring having upper and lower
surfaces. Making the cuts at an angle to each other creates a bone ring with
upper and lower surfaces that are angled relative to each other. The angular
relationship of the upper and lower surface of the bone ring, when
subsequently
formed into an implant and implanted into the spine, position the adjacent
vertebral bodies in angular relationship to each other to restore the natural
curvature of the spine, such as lordosis for example.
The bone may be machined to form an implant having a selected shape
suitable for the intended purpose. Examples of tools which may be used to
machine the implant include, but are not limited to, burrs, reamers, mills,
saws,
trephines, chisels, and the like. For example only, the leading end may be
shaped to be approximately half a circle from side to side. The sides may be
machined to be at least in part straight. The trailing end may be machined to
any
desired shape suitable for the intended purpose and may preferably be shaped
to
conform to the anatomical contour of the adjacent vertebral bodies between
which the implant is adapted to be inserted. The medullary canal preferably
forms a passage adapted to hold bone growth promoting materials and/or
substances. Where it is appropriate, it may be desirable to preserve at least
a
portion of the natural curvature of the perimeter of the bone ring as part of
the
configuration of the implant shape.
Implant 100A preferably has a length greater than one-half the depth of
the vertebral bodies adjacent the disc space into which the implant is adapted
to
be inserted as measured between the anterior and posterior aspects of the
vertebral bodies. Implant 100A also preferably has a maximum width that is
greater than one-half the width of the adjacent vertebral bodies into which
the
implant is adapted to be inserted.
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For any of the embodiments of the implants of the present invention made
at least in part of bone, instead of being machined from a single bone
portion, the
implant can be manufactured from a composite bone material which may include
at least one of cortical bone fibers, bone filaments, bone particles, or bone
dust,
and a binding material which may or may not be bioactive and/or bioresorbable
such as a plastic, ceramic, for example. By way of example only and not
limitation, bioresorbable materials may include polygalactone. Once formed,
the
composite implant material may be machined or molded, into the desired shape.
Figs. 13-18 show an implant 1008 preferably made of a material other
than bone in accordance with a preferred embodiment of the present invention.
Implant 1008 has a leading end 1028 for insertion first into the disc space
between two adjacent vertebral bodies and a trailing end 1048 opposite leading
end 1028, and opposite sides 1108, 1128 therebetween. Leading end 1028 is
preferably configured to match the contour of leading edge 52 of implantation
space 50 and trailing end 1048 is preferably configured to conform to the
contour
of the anterior aspect of the vertebral body at trailing portion 54 of
implantation
space 50. Sides 11 OB, 1128 are generally planar and preferably correspond to
the configuration of side edges 56, 58 of implantation space 50.
In a preferred embodiment of the present invention, leading end 1028,
trailing end 1048, and opposite sides 1108, 1128 may have various
configurations. Leading end 1028 is preferably is in the shape of
approximately
half a first circle from side to side. Where the implantation space is
prepared into
the vertebral bodies to have a lip or ridge that is at least in part curved,
leading
end 1028 may be adapted to abut at least that portion of the implantation
space.
One or both of sides 11 OB, 1128 may also be formed to be at least in part
oriented generally parallel to the mid-longitudinal axis of implant 1008
and/or to
each other. One or both of sides 1108, 1128 may include at least one opening
1198 to permit for the growth of bone therethrough and into implant 1 OOB,
though
the invention is not so limited. Further, leading end 1028 may be tapered to
facilitate insertion of implant 1008 between the two adjacent vertebral
bodies.
Trailing end 1048 preferably forms an arc of a second circle from side to
side having a radius greater than the radius of the first circle associated
with
leading end 1028. Preferably, at least a portion of trailing end 1048 is
adapted to
conform to at least a portion of the peripheral contour of the anterior aspect
of the
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vertebral bodies adjacent the disc space into which the implant is adapted to
be
inserted, though the invention is not so limited.
Fig. 18 shows that implant 1008 preferably has a driver opening 1168 at
trailing end 1048 for cooperatively engaging an instrument for installing
implant
100 into the implantation space. Driver opening 1168 is preferably configured
for
threaded engagement with an insertion instrument.
Figs. 14, 16, and 17 show at least a portion of upper and lower surFaces
1068, 1088 in an angular relationship to each other from trailing end 1048 to
leading end 1028 for allowing for angulation of the adjacent vertebral bodies
relative to each other. Preferably, upper and lower surfaces 1068, 1088 are
non-
arcuate in a direction along the mid-longitudinal axis of implant 1008.
Implant
1008 preferably has a maximum height that is less than the maximum width of
the implant.
As shown in Fig. 15, upper and lower surfaces 1068, 1088 preferably
have at least one opening 1148 passing therethrough between leading and
trailing ends 1028, 1048, respectively, and opposite sides 1108, 1128.
Openings 114 are preferably adapted to hold bone growth promoting material to
permit for the growth of bone from vertebral body to vertebral body through
openings 1148 and through implant 1008. Upper and lower surfaces 1068,
1088 may also be porous and may include a bone ingrowth surface.
As shown in Fig. 15, the implants described herein may include a bone-
engaging surface 1188 such as knurling for example. Bone engaging surface
1188 is configured to engage the bone of the adjacent vertebral bodies to
maintain implant 1008 within the adjacent vertebral bodies after implantation.
Other preferred embodiments of bone-engaging surfaces may include the
surfaces of the implant being roughened, ratcheted, splined, or may include at
least one protrusion to penetrably engage the bone of the vertebral bodies.
The base material used to form the implant of Figs. 13-18 is preferably a
material other than bone. In a preferred embodiment, the material of the
implant
may be formed of an artificial material such as metal including, but not
limited to,
titanium and its alloys, ASTM material, cobalt chrome, or tantalum, ceramic,
various surgical grade plastics, plastic composites, carbon fiber composites,
coral, and can include artificial materials which are at least in part
bioresorbable.
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Implant 100B preferably has a length greater than one-half the depth of
the vertebral bodies adjacent the disc space into which the implant is adapted
to
be inserted as measured between the anterior and posterior aspects of the
vertebral bodies. Implant 100B also preferably has a maximum width that is
greater than one-half the width of the adjacent vertebral bodies into which
the
implant is adapted to be inserted.
Fig. 19 shows another preferred embodiment of the present invention of
an implant made of bone or a bone composite for use in the cervical spine
generally referred to by the numeral 200A. Implant 200A is preferably
configured
to conform to the shape of implantation space 60 formed in the endplates of
adjacent cervical vertebral bodies with instrumentation and methods similar to
those used in association with the lumbar spine but modified for use in the
cervical spine. Implant 200A may, for example, have a leading end 202A formed
to have a shape of approximately one-half a first circle from side to side.
Trailing
end 204A preferably may be formed as an arc of a second circle from side to
side
that intersects the curvature of leading end 202A from side to side. The
radius of
the second circle associated with trailing end 204A is preferably greater that
the
radius of the first circle associated with leading end 202A.
Fig. 20 shows another preferred embodiment of the present invention of
an implant made of a material other than bone for use in the cervical spine
generally referred to by the numeral 200B. Implant 200B is preferably
configured
to conform to the shape of implantation space 60 formed in the endplates of
adjacent cervical vertebral bodies. Implant 200B may, for example, have a
leading end 202B formed to have a shape of approximately one-half a first
circle
from side to side. Trailing end 204B preferably may be formed as an arc of a
second circle from side to side that intersects the curvature of leading end
202B
from side to side. The radius of the second circle associated with trailing
end
204B is preferably greater that the radius of the first circle associated with
leading
end 202B. .
Figs. 21-26 show an implant 300A preferably made of bone or a bone
composite material in accordance with another preferred embodiment of the
present invention adapted for use from the anterior approach to the spine.
Fig.
21 shows a rear perspective view of implant 300A. Implant 300A includes at
least two members 300A', 300A" that are adapted to be placed side by side with
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one another. Member 300A' is preferably, but need not be a mirror image of
member 300A". The description of member 300A' is equally applicable to
member 300A". Member 300A' has a leading portion 302A' for insertion first
into
the disc space between two adjacent vertebral bodies and a trailing portion
304A'
opposite leading portion 302A'. Member 300A' has a top 306A', a bottom 308A',
an interior side 310A', and an exterior facing side 312A' opposite interior
facing
side 31 OA'. As used herein, the phrase "interior side" describes the side of
the
member adapted to be orientated toward the interior side of another member
when a pair of members are inserted side by side into the disc space. In a
preferred embodiment, interior side 310A' includes at least a portion of the
medullary canal of the bone ring.
Leading portions 302A', 302A" of each member 300A', 300A",
respectively, form leading end 302A of implant 300A when the members are
placed side by side to one another. Leading end 302A of implant 300A is
preferably configured in the shape of one-half a first circle from side to
side.
Trailing end 304A, composed of trailing portions 304A', 304A" when members
300A', 300A" are placed side by side to one another, may, but need not be
formed as an arc of a second circle side to side having a radius greater than
a
radius of the first circle associated with leading end 302A of implant 300A.
Member 300A' is placed side by side with member 300A" so that the
portion of the medullary canal of interior side 31 OA' of each member are
adjacent
one another to form a passage 314A through implant 300A. Preferably passage
314A is adapted to hold bone growth promoting material to permit for the
growth
of bone from vertebral body to vertebral body through passage 314A. Member
300A' preferably has a maximum width W that is less than approximately one-
half
the width of the adjacent vertebral bodies into which the member is adapted to
be
inserted. Also, the combined width of both members 300A', 300A" is preferably
greater than one-half the width of the adjacent vertebral bodies into which
the
members are adapted to be inserted.
Members 300A', 300A" provide the added advantage in that each member
can be inserted through a smaller space than a single larger implant, to
achieve
the same effect as the larger implant.
Figs. 27-32 show an implant 300B made of a material other than bone in
accordance with another preferred embodiment of the present invention adapted
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for use from the anterior approach to the spine. Fig. 27 shows a rear
perspective
view of implant 3008. Implant 3008 includes at least two members 3008', 3008"
that are adapted to be placed side by side with one another. Member 3008' is
preferably, but need not be a mirror image of member 3008". The description
ofi
member 3008' is equally applicable to member 3008". Member 3008' has a
leading portion 3028' for insertion fist into the disc space between two
adjacent
vertebral bodies and a trailing portion 3048' opposite leading portion 3028'.
Member 3008' has a top 3068', a bottom 3088', an interior side 3108', and an
exterior facing side 3128' opposite interior facing side 31 OB'.
Leading portions 3028', 3028" of each member 3008', 3008",
respectively, form leading end 3028 of implant 3008 when the members are
placed side by side to one another. Leading end 3028 of implant 3008 is
preferably configured in the shape of one-half a first circle from side to
side.
Trailing end 3048, composed of trailing portions 3048', 3048" when members
3008', 3008" are placed side by side to one another, may, but need not be
formed as an arc of a second circle side to side having a radius greater than
a
radius of the first circle associated with leading end 3028 of implant 3008.
Member 300' is placed side by side with member 3008" so that a portion
of interior side 3108' of each member are adjacent one another. Top 3068' and
bottom 3088' preferably have at least one opening 3148' passing therethrough
between leading and trailing portions 3028', 3048', respectively, and sides
3108',
3128'. Openings 3148' are adapted to hold bone growth promoting material to
permit for the growth of bone from vertebral body to vertebral body through
openings 3148. Interior side 3108' may also include at least one opening 3148'
passing therethrough configured to permit bone growth between and into
adjacent members 3008', 3008". Member 3008' preferably has a maximum
width W that is less than approximately one-half the width of the adjacent
vertebral bodies into which the member is adapted to be inserted. Also, the
combined width of both members 3008', 3008" is preferably greater than one-
half the width of the adjacent vertebral bodies into which the members are
adapted to be inserted.
Members 3008', 3008" provide the added advantage in that each member
can be inserted through a smaller space than a single larger implant, to
achieve
the same effect as the larger implant.
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Fig. 33 shows an implant 400A in accordance with another preferred
embodiment of the present invention adapted for use from an anterior approach
to the spine. Implant 400A is similar to implant 100A and has a leading end
402A
that is shaped as approximately one-half a first circle. Implant 400A is
adapted to
have a maximum width between sides 410A, 412A that is less than one-half of
the width of the adjacent vertebral bodies into which implant 400A is adapted
to
be inserted. Trailing end 404A forms an arc of a second circle having a radius
that is substantially greater than the radius of the first circle associated
with
leading end 402A. Implants 400A can be made of bone, a bone composite, or a
material other than bone.
Fig. 34 shows an implant 500A in accordance with another preferred
embodiment of the present invention adapted for use from an anterior approach
to the spine. Implant 500A is similar to implant 400A except that both leading
end 502A and trailing end 504A are preferably in the shape of a half circle
side to
side. Implants 500A can be made of bone, a bone composite, or a material other
than bone.
Fig. 35 shows an implant 600A in accordance with another preferred
embodiment of the present invention adapted for use from a posterior approach
to the spine. Implant 600A is similar to implant 400A except that trailing end
604A is preferably at least in part straight from side to side. Implants 600A
can
be made of bone, a bone composite, or a material other than bone.
Figs. 36-42 show an implant 700A made of bone or a bone composite in
accordance with another embodiment of the present invention. Implant 700A is
similar to implant 100A and has a leading end 702A in the shape of
approximately one-half a first circle A and a trailing end 704A formed as an
arc of
a second circle C. Implant 700A preferably includes straight portions 711A,
713A
along at least a portion of sides 710A, 712A, respectively, that are
preferably
parallel to each other along lines P. Implant 700A also preferably includes a
curved transition from each straight portion 711A, 713A of sides 710A, 712A,
respectively, to trailing end 704A to form rounded portions 715A, 717A,
respectively. Rounded portion 715A, 717A may be an arc of a third circle E
that
preferably has a radius less than the radii of circle A associated with
leading end
702A and/or circle C associated with trailing end 704A.
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In a preferred embodiment, implant 700A may be machined so as to be
adapted to receive through bone screw receiving holes 720A at trailing end
704A
at least a pair of opposed appropriately sized bone screws 722A preferably,
but
not necessarily, made of cortical bone. Bone engaging screws 722A may be
aligned or offset from each other. At least one screw 722A engages each of the
vertebral bodies adjacent a disc space to be fused and into which implant 700A
is
implanted. A purpose of the bone screws is to rigidly secure the implant
within
the vertebral segment. A further purpose is to pull each of the adjacent
vertebral
bodies toward the implant and towards each other. Trailing end 704A of implant
700A preferably includes a recess 724A having bone screw receiving holes 720A
therein and an opening 726A configured to cooperatively receive a locking cap
728A adapted to lock at least one bone screw 722A to implant 700A.
As shown in Fig. 41, implant 700A is,preferably further machined and
adapted to receive a lock 728A, preferably made of cortical bone, at trailing
end
704A for securing bone engaging screws 722A therein and preventing the screws
from backing out. Locking cap 728A has a top 730A, a stem 732A, and a tool
engagement area 734A. In use, locking cap cooperatively engages trailing end
704A of implant 700A at opening 726A to lock at least one bone screw to
implant
700A. If desired, locking cap 728A may include a thread on stem 732A to allow
locking cap 728A to rotationally engage implant 700A.
Fig. 42 shows another preferred embodiment of a locking cap, generally
referred to by the numeral 736A. Locking cap 736A includes a top 738A having a
thread 740A at its outer perimeter that is adapted to cooperatively engage a
corresponding threaded recess in the implant.
The bone implant, bone screws, and/or locks can be made of a
bioresorbable material, including but not limited to cortical bone, plastics
and
composite plastics. Suitable plastics may include those comprising iactides,
galactides, glycolide, capronlactone, trimethylene carbonate, or dioxanone in
various polymers, and/or combinations thereof.
Figs. 43-49 show an implant 700B made of a material other than bone in
accordance with another embodiment of the present invention. Implant 700B is
similar to implant 100B and has a leading end 702B in the shape of
approximately one-half a first circle A and a trailing end 704B formed as an
arc of
a second circle C. Implant 700B preferably includes straight portions 711 B,
713B
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along at least a portion of sides 710B, 712B, respectively, that are
preferably
parallel to each other along lines P. Implant 700B also preferably includes a
curved transition from each straight portion 711 B, 713B of sides 71 OB, 712B,
respectively, to trailing end 704B to form rounded portions 7158, 717B,
respectively. Rounded portion 715B, 717B may be an arc of a third circle E
that
preferably has a radius less than the radii of circle A associated with
leading end
702B and/or circle C associated with trailing end 704B.
In a preferred embodiment, implant 700B may be adapted to receive
through bone screw receiving holes 720B at trailing end 704B at least a pair
of
opposed appropriately sized bone screws 722B. Bone engaging screws 722B
may be aligned or offset from each other. At least one screw 722B engages
each of the vertebral bodies adjacent a disc space to be fused and into which
implant 700B is implanted. Trailing end 704B of implant 700B preferably
includes
a recess 724B having bone screw receiving holes 720B therein and an opening
726B configured to cooperatively receive a locking cap 728B'adapted to lock at
least one bone screw 722B to implant 700B.
As shown in Fig. 48, implant 700B is preferably adapted to receive a lock
728B at trailing end 704B for securing bone engaging screws 722B therein and
preventing the screws from backing out. Locking cap 728B has a top 730B, a
stem 732B, and a tool engagement area 734B. In use, locking cap cooperatively
engages trailing end 704B of implant 700B at opening 726B to lock at least one
bone screw to implant 700B. If desired, locking cap 728B may include a thread
on stem 7328 to allow locking cap 728B to rotationally engage implant 700B.
Fig. 49 shows another preferred embodiment of a locking cap, generally
referred to by the numeral 736B. Locking cap 736B includes a top 738B having a
thread 740B at its outer perimeter that is adapted to cooperatively engage a
corresponding threaded recess in the implant.
Implant 700B, bone screws 722B, and/or locks 728B, 736B can be made
of a bioresorbable material, including but not limited to plastics and
composite
plastics. Suitable plastics may include those comprising lactides, galactides,
glycolide, capronlactone, trimethylene carbonate, or dioxanone in various
polymers, and/or combinations thereof.
By way of example only and not limitation, for use in the lumbar spine, the
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a width of approximately, 30-38 mm, and a height (max) of approximately 8-20
mm. The radius of curvature of the leading end may be approximately 15-19 mm
and the radius of curvature of the trailing end may be approximately 20-30 mm.
In any of the embodiments of the present invention, the implant may
include, be made of, treated, coated, filled, used in combination with, or
have an
opening, a hollow, or a passage for containing artificial or naturally
occurring
mafierials and/or substances suitable for implantation in the human spine.
These
materials and/or substances include any source of osteogenesis, bone growth
promoting materials, bone, bone derived substances or products, demineralized
bone matrix, mineralizing proteins, ossifying proteins, bone morphogenetic
proteins, hydroxyapatite, genes coding for the production of bone, and bone
including, but not limited to, cortical bone. The implant can include at least
in part
of materials that are bioabsorbable and/or resorbable in the body such as bone
and/or bone growth promoting materials. The implant of the present invention
can be formed of a porous material or can be formed of a material that
intrinsically participates in the growth of bone from one of adjacent
vertebral
bodies to the other of adjacent vertebral bodies. Where such implants are for
posterior implantation, the trailing ends of such implants may be treated
with,
coated with, or used in combination with chemical substances to inhibit scar
tissue formation in the spinal canal. The implant of the present invention may
be
modified, or used in combination with materials to make it antibacterial, such
as,
but not limited to, electroplating or plasma spraying with silver ions or
other
substance. At least a portion of the implant may be treated to promote bone
ingrowth between the implant and the adjacent vertebral bodies. The implant of
the present invention may be used in combination with a spinal fixation
implant
such as any object, regardless of material, that can be inserted into any
portion of
the spine, such as but not limited to interbody spinal implants, structural
bone
grafts, mesh, cages, spacers, staples, bone screws, plates, rods, tethers of
synthetic cords or wires, or other spinal fixation hardware
While the shapes of the various aspects of the implant have been
described precisely, the scope of the present invention is not so limited and
it is
readily anticipated that the contours may be interrupted by minor
irregularities
such as for example only for the purpose of engaging the bone, encouraging the
ingrowth or through growth of bone.
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While specific innovative features were presented in reference to specific
examples, they are just examples, and it should be understood that various
combinations of these innovative features beyond those specifically shown are
taught such that they may now be easily alternatively combined and are hereby
anticipated and claimed.
22

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