U.S. patent application number 10/393464 was filed with the patent office on 2004-09-23 for height adjustable vertebral body and disc space replacement devices.
Invention is credited to Berry, Bret M..
Application Number | 20040186569 10/393464 |
Document ID | / |
Family ID | 32988160 |
Filed Date | 2004-09-23 |
United States Patent
Application |
20040186569 |
Kind Code |
A1 |
Berry, Bret M. |
September 23, 2004 |
Height adjustable vertebral body and disc space replacement
devices
Abstract
A vertebral replacement device for supporting adjacent vertebrae
includes a vertebral body or vertebral body member having at least
one of an upper or lower member adjustably engaged at one end
thereof. A spacer can be engaged to the upper or lower member to
further increase the height of the vertebral replacement device.
The vertebral replacement device can have a chamber extending
therethrough for fusion of the supported vertebrae.
Inventors: |
Berry, Bret M.; (Cordova,
TN) |
Correspondence
Address: |
Woodard, Emhardt, Naughton,
Moriarty and McNett LLP
Bank One Center /Tower
111 Monument Circle, Suite 3700
Indianapolis
IN
46204-5137
US
|
Family ID: |
32988160 |
Appl. No.: |
10/393464 |
Filed: |
March 20, 2003 |
Current U.S.
Class: |
623/17.11 |
Current CPC
Class: |
A61F 2002/30125
20130101; A61F 2002/30235 20130101; A61F 2310/00293 20130101; A61F
2310/00329 20130101; A61F 2002/30062 20130101; A61F 2002/3055
20130101; A61F 2002/30451 20130101; A61F 2002/30507 20130101; A61F
2002/30092 20130101; A61F 2002/30784 20130101; A61F 2002/30818
20130101; A61F 2002/30599 20130101; A61F 2002/30879 20130101; A61F
2002/30154 20130101; A61F 2/28 20130101; A61F 2002/30113 20130101;
A61F 2002/30425 20130101; A61F 2/4465 20130101; A61F 2002/30187
20130101; A61F 2002/2835 20130101; A61F 2002/30774 20130101; A61F
2002/30331 20130101; A61F 2002/30474 20130101; A61F 2002/30426
20130101; A61F 2002/30593 20130101; A61F 2310/00359 20130101; A61F
2/442 20130101; A61F 2002/30601 20130101; A61F 2310/00023 20130101;
A61F 2310/00017 20130101; A61F 2002/30405 20130101; A61F 2002/448
20130101; A61F 2002/30156 20130101; A61F 2310/00029 20130101; A61F
2002/2817 20130101; A61F 2002/305 20130101; A61F 2/30965 20130101;
A61F 2/44 20130101; A61F 2002/30616 20130101; A61F 2002/30153
20130101; A61F 2002/30433 20130101; A61F 2002/30411 20130101; A61F
2/30724 20130101 |
Class at
Publication: |
623/017.11 |
International
Class: |
A61F 002/44 |
Claims
What is claimed is:
1. A vertebral replacement device, comprising: a height-adjustable
sub-assembly extending along a longitudinal axis; and a spacer
engaged at one end of said sub-assembly and axially constrained to
said sub-assembly, said spacer including a first height extending
from said end of said sub-assembly, wherein said first height is
adapted for said spacer to maintain a spinal disc space between
adjacent vertebrae when said spacer is disengaged from said
sub-assembly and positioned in the spinal disc space.
2. The device of claim 1, wherein said sub assembly comprises: a
connecting member including a first extension and an opposite
second extension extending along the longitudinal axis; a first
member adjustably engaged along said first extension; and a second
member adjustably engaged along said second extension, wherein said
sub-assembly height is adjustable by adjusting a position of at
least one of said first and second members along said corresponding
first and second extensions.
3. The device of claim 2, wherein said first member is threadingly
engaged to said first extension and said second member is
threadingly engaged to said second extension.
4. The device of claim 3, wherein said first and second extensions
each include an external thread pattern and said first and second
members each include an inner wall defining a chamber therethrough,
said inner wall defining a thread pattern to threadingly engage
said external thread pattern of respective ones of said first and
second extensions.
5. The device of claim 1, further comprising at least one flexible
engaging member releasably engaging said spacer to said one end of
said first member.
6. The device of claim 5, further comprising an extension sleeve
extending between and coupling said spacer to said sub-assembly,
said extension sleeve positionable in a chamber opening at said one
end of said sub-assembly and in a chamber of said spacer opening
toward said chamber of said sub-assembly.
7. The device of claim 6, wherein said at least one flexible
engaging member includes a flexible engaging member at each of said
extension sleeve, wherein each of said flexible engaging members is
integrally formed with said extension sleeve and positionable in a
respective one of said chambers of said sub-assembly and said
spacer.
8. The device of claim 7, wherein one of said flexible engaging
members includes an engaging portion oriented toward a wall of said
sub-assembly and the other of said flexible engaging members
includes an engaging portion oriented toward a wall of said spacer,
said engaging portions engaging said respective walls to axially
secure said spacer and said sub-assembly to one another.
9. The device of claim 8, wherein each of said flexible engaging
members is inwardly deflectable and resiliently biased toward a
pre-insertion configuration to releasably engage said inner
wall.
10. The device of claim 1, wherein said sub-assembly and said
spacer each include chambers extending therethrough to allow fusion
through the device.
11. The device of claim 1, further comprising a second spacer
engaged to an opposite end of said sub-assembly and axially
constrained relative thereto.
12. The device of claim 1, wherein said second spacer is identical
to said spacer.
13. The device of claim 1, wherein said spacer includes an upper
surface opposite said one end, said upper surface including a
convex surface profile.
14. The device of claim 13, wherein said upper surface includes a
plurality of holes therethrough in communication with a chamber in
said second spacer, said chamber opening adjacent said one end of
said sub-assembly.
15. The device of claim 1, wherein said sub-assembly includes a
first member and a second member threadingly engageable to said
first member, said one end comprising an end of said second member
opposite said first member.
16. The device of claim 15, wherein second member includes a second
height from said end to an opposite end adjacent said first member,
said second height adapted for said second member to maintain a
spinal disc space between adjacent vertebrae when said second
member is disengaged from said first member and positioned in the
spinal disc space.
17. A vertebral replacement device, comprising: a connecting member
including a body and a threaded extension extending from said body
along a longitudinal axis; and a member including a wall extending
about a chamber opening toward at least one end of said member,
said extension being positionable in said chamber of said member
and threadingly engageable to at least a portion of said member,
wherein said chamber includes a non-circular shape transverse to
said longitudinal axis along said portion of said member.
18. The device of claim 17, wherein said chamber is defined by an
inner surface of said wall of said member, said inner surface
including a thread pattern to threadingly engage said
extension.
19. The device of claim 18, wherein at least a portion of said
inner surface is non-threaded.
20. The device of claim 17, wherein said chamber opens at each end
of said member.
21. The device of claim 20, wherein said connecting member includes
a chamber extending therethrough in communication with said chamber
of said member when said member is engaged to said connecting
member.
22. The device of claim 17, wherein: said connecting member
includes a second threaded extension extending from said body
opposite said threaded extension along said longitudinal axis; and
a second member including wall extending about a chamber opening
toward at least one end of said member, said second extension being
positionable in said chamber of said second member and threadingly
engageable to at least a portion of said second member, wherein
said chamber includes a non-circular shape transverse to said
longitudinal axis along said portion of said second member.
23. The device of claim 22, wherein each of said chambers is
defined by an inner surface of said wall of each of said members,
said inner surfaces each including a thread pattern to threadingly
engage respective ones of said extensions.
24. The device of claim 23, wherein at least a portion of said
inner surface of said chamber of each of said members is
non-threaded.
25. The device of claim 23, wherein said chamber of each of said
members is open at each end thereof.
26. The device of claim 25, wherein said connecting member includes
a chamber extending therethrough in communication with said chamber
of each of said members when said members are engaged to respective
ones of said extensions of said connecting member.
27. The device of claim 17, further comprising bone growth material
in said chamber of said member.
28. The device of claim 27, wherein said bone growth material
includes one or more selected from group consisting of: bone
morphogenetic protein, transforming growth factor .beta.1,
insulin-like growth factor 1, platelet-derived growth factor,
fibroblast growth factor, and LIM mineralization protein (LMP).
29. The device of claim 27, wherein said bone growth material is
provided in a carrier having a form selected from the group
consisting of: a sponge, a block, folded sheet, putty, and
paste.
30. The device of claim 17, wherein at least one of said member and
said connecting member are comprised of resorbable material
selected from the group consisting of: hard tissues, connective
tissues, demineralized bone matrix, polylactide, polyglycolide,
tyrosine-derived polycarbonate, polyanhydride, polyorthoester,
polyphosphazene, calcium phosphate, hydroxyapatite, bioactive
glass, and combinations thereof
31. The device of claim 17, wherein at least one of said member and
said connecting member are comprised of non-resorbable material
selected from the group consisting of: non-reinforced polymers,
carbon-reinforced polymer composites, PEEK, PEEK composites,
shape-memory alloys, titanium, titanium alloys, cobalt chrome
alloys, stainless steel, ceramics and combinations thereof.
32. The device of claim 17, further comprising a spacer engaged to
said member opposite said connecting member, said spacer including
a first height extending from an end of said member opposite said
one end, wherein said first height is adapted for said spacer to
maintain a spinal disc space between adjacent vertebrae when said
spacer is disengaged from said member and positioned in the spinal
disc space.
33. The device of claim 32, wherein said member includes a second
height from said one end to said opposite end, said second height
adapted for said member to maintain a spinal disc space between
adjacent vertebrae when said member is disengaged from said
connecting member and positioned in the spinal disc space.
34. The device of claim 17, wherein said member includes a height
from said one end to an opposite end, said height adapted for said
member to maintain a spinal disc space between adjacent vertebrae
when said member is disengaged from said connecting member and
positioned in the spinal disc space.
35. A vertebral replacement device, comprising: a connecting member
including a body and first and second threaded extensions extending
from said body along a longitudinal axis; a first member
threadingly engageable to said first threaded extension, wherein
said first member includes a body extending between a first end and
a second end, said body including a height between said first and
second ends and adapted to restore a spinal disc space when said
first member is positioned therein; and a second member threadingly
engageable to said second threaded extension, wherein said second
member includes a body extending between a first end and a second
end, said body having a height between said first and second ends
and adapted to restore a spinal disc space when said second member
is positioned therein.
36. The device of claim 35, wherein said body of each of said first
and second members includes a chamber extending between said first
and second ends thereof.
37. The device of claim 36, wherein said chamber of each of said
first and second members opens at least at one of said first and
second ends of said body thereof.
38. The device of claim 36, wherein said chamber of each of said
first and second members opens at each of said first and second
ends of said body thereof.
39. The device of claim 36, wherein said connecting member includes
a chamber extending therethrough in communication with said
chambers of each of said first and second members.
40. The device of claim 39, further comprising bone growth material
in said chamber of said member.
41. The device of claim 40, wherein said bone growth material
includes one or more selected from group consisting of: bone
morphogenetic protein, transforming growth factor .beta.1,
insulin-like growth factor 1, platelet-derived growth factor,
fibroblast growth factor, and LIM mineralization protein (LMP).
42. The device of claim 40, wherein said bone growth material is
provided in a carrier having a form selected from the group
consisting of: a sponge, a block, folded sheet, putty, and
paste.
43. The device of claim 35, further comprising: a first spacer
engageable at one of said first and second ends of said first
member opposite said connecting member; and a second spacer
engageable at one of said first and second ends of said second
member opposite said connecting member.
44. The device of claim 43, wherein each of said first and second
spacers includes a body extending between a first end and a second
end thereof, said body of each of said spacers including a height
between said first and second ends adapted to restore a spinal disc
space when a selected one of said first and second spacers is
positioned therein.
45. The device of claim 43, further comprising: at least one
flexible engaging member releasably engaging said first spacer to
said first member; and at least one flexible engaging member
releasably engaging said second spacer to said second member.
46. The device of claim 45, further comprising: a first extension
sleeve extending between and coupling said first spacer to said
first member, said first extension sleeve positionable in a chamber
opening at said one end of said first member and in a chamber of
said first spacer opening toward said chamber of said first member;
and a second extension sleeve extending between and coupling said
second spacer to said second member, said second extension sleeve
positionable in a chamber opening at said one end of said second
member and in a chamber of said second spacer opening toward said
chamber of said second member
47. The device of claim 46, wherein: said at least one flexible
engaging member includes a flexible engaging member at each end of
said first extension sleeve, wherein each of said flexible engaging
members is integrally formed with said first extension sleeve and
positionable in a respective one of said chambers of said first
member and said first spacer; and said at least one flexible
engaging member includes a flexible engaging member at each end of
said second extension sleeve, wherein each of said flexible
engaging members is integrally formed with said second extension
sleeve and positionable in a respective one of said chambers of
said second member and said second spacer.
48. The device of claim 47, wherein each of said flexible engaging
members includes an engaging portion oriented toward a wall of an
adjacent one of said first and second spacers and said first and
second members.
49. The device of claim 48, wherein each of said flexible engaging
member is inwardly deflectable and resiliently biased toward a
pre-insertion configuration for said engaging portion to releasably
engage said adjacent wall.
50. The device of claim 45, wherein: said first spacer includes a
first extension positonable in a chamber of said first member, said
at least one flexible engaging member comprising a portion of said
extension of said first spacer; and said second spacer includes a
second extension positionable in a chamber of said second member,
said at least one flexible engaging member comprising a portion of
said extension of said second spacer.
Description
BACKGROUND
[0001] The present invention is directed to devices for replacement
of one or more vertebral bodies and/or one or more disc spaces
between vertebrae of a spinal column.
[0002] The repair and reconstruction of bony structures is
sometimes accomplished by directly fixing adjacent bony structures
to each other, such as by a plate. In other instances, bone growth
inducing material can be introduced between the adjacent bony
structures, which over time results in a solid bony connection. In
some instances, the adjacent bony structures are not sufficiently
strong or stable as the bone heals or the bone grows between the
adjacent structures through the bone growth inducing material. In
these instances, mesh structures or cages have been provided to
engage the adjacent bony structures to provide additional
stability. The cages are generally hollow and can be configured to
contact the harder cortical bone of the adjacent bony structures.
The hollow portion of the cages can be filled with bone growth
inducing material. Devices have also been provided to replace a
removed vertebral body and to provide a support structure between
the remaining vertebrae on either side of the one or more removed
vertebral bodies.
[0003] There remains a need for improved devices for replacing one
or more vertebral bodies and/or one or more disc spaces in a spinal
column. The present invention is directed to satisfying these
needs, among others.
DESCRIPTION OF THE FIGURES
[0004] FIG. 1 is a perspective view of a vertebral replacement
device according to one embodiment of the present invention.
[0005] FIG. 2 is an exploded perspective view of the vertebral
replacement device of FIG. 1.
[0006] FIG. 3 is a side elevation view of the vertebral replacement
device of FIG. 1.
[0007] FIG. 4 is an end view of the vertebral replacement device of
FIG. 1.
[0008] FIG. 5 is an elevational view of an end member comprising a
portion of the vertebral replacement device of FIG. 1.
[0009] FIG. 6 is an end view of the end member of FIG. 5.
[0010] FIG. 7 is a perspective view of another embodiment vertebral
replacement device.
[0011] FIG. 8 is a perspective view of another embodiment vertebral
replacement device.
[0012] FIG. 9 is a plan view of the device of FIG. 8.
[0013] FIG. 10 is a partially exploded perspective view of another
embodiment vertebral replacement device.
[0014] FIG. 11 is a section view showing the engagement between
components of the vertebral replacement device of FIG. 10.
[0015] FIG. 12 is an elevation view of an engaging member
comprising a portion of the vertebral replacement device of FIG.
10.
[0016] FIG. 13 is a partially exploded perspective view of another
embodiment vertebral replacement device.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0017] For the purpose of promoting an understanding of the
principles of the invention, reference will now be made to the
illustrated embodiments thereof and specific language will be used
to describe the same. It will nevertheless be understood that no
limitation of the scope of the invention is thereby intended. Any
such alterations and further modifications in the invention, and
any such further applications of the principles of the invention as
described herein are contemplated as would normally occur to one
skilled in the art to which the invention relates.
[0018] The present invention relates to devices for replacing one
or more vertebral bodies in the spinal column and/or one or more
disc spaces between adjacent vertebrae. It is contemplated that the
replacement devices will support adjacent ones of the intact
vertebrae during fusion thereof. It is further contemplated that
one or more components or members of the vertebral replacement
devices can be positioned in a disc space between adjacent
vertebrae for supporting the adjacent vertebrae during fusion. The
vertebral replacement devices also have application in corpectomy
and disc replacement procedures where fusion is not desired.
[0019] The vertebral replacement device can have a tubular form
with a hollow chamber extending therethrough. Other forms are also
contemplated, including devices without a hollow chamber, devices
with multiple chambers, and devices with one or more chambers that
extend only partially therethrough. The adjacent vertebrae are
supported by opposite ends of the device and the chamber can be
filled with bone growth inducing or osteogenetic material. The ends
of the device include bearing surfaces to engage an adjacent
vertebral endplates.
[0020] In one embodiment, the vertebral replacement device includes
a connecting member and an upper member attached to an upper end of
the connecting member and a lower member attached to a lower end of
the connecting member. The upper and lower members can be adjusted
relative to the connecting member to provide the desired overall
height for the device. Each of the upper and lower members can have
a generally kidney bean cross-sectional shape in the plane
transverse to the central axis of the assembled device. Other
cross-sectional shapes are also contemplated, including circular,
racetrack-shaped, rectangular, square, oval, D-shaped, triangular,
boomerang, banana, or other polygonal or non-circular shape. Each
of the upper and lower members can include an interior chamber. The
connecting member can also include an interior chamber that
communicates with the interior chambers of the upper and lower
members engaged thereto.
[0021] In one embodiment, the upper and lower members can be
fabricated from a tubular mesh having apertures through its wall.
One example of a tubular mesh is provided in U.S. Pat. No.
5,897,556, which is incorporated herein by reference in its
entirety. Further forms contemplate that the upper and lower
members and connecting member can be a tubular body with solid
walls or wall structure including one or more openings.
[0022] The upper and lower members can be rotatably engaged with
the connecting member. The connecting member includes an upper
extension and a lower extension extending therefrom. The upper and
lower extensions include a thread pattern to engage a thread
pattern of the upper and lower members. The interlocking threads
provide axial restraint of the upper and lower members relative to
the connecting member, and allow the overall height of the device
to be adjusted while maintaining axial restraint. In one
embodiment, the extensions are received in an interior chamber or
opening at respective ends of the upper and lower members.
[0023] In one embodiment, the upper and lower members include an
interior chamber having a non-circular cross-section. The inner
wall surface of the upper and lower members includes a thread
pattern to threadingly engage upper and lower extensions of the
connecting member. In one embodiment, the thread pattern is formed
along only a portion of the inner wall surface extending around the
non-circular chamber.
[0024] In one embodiment, the height of the device can be engaged
by adding one or more spacers to the end of at least one of the
upper and lower members. The spacers can be axially secured to the
respective upper or lower member by a flexible engaging member. In
one form, an extension sleeve extends between chambers of the upper
or lower member and the spacer to secure the spacer to the
respective upper or lower member. In another form, one of the
spacer and the adjacent upper or lower member includes an extension
positionable in a chamber of the other of the spacer and the one of
the upper or lower member.
[0025] Any one or all of the members of the vertebral replacement
devices can be made from any biocompatible material, including
synthetic or natural autograft, allograft or xenograft tissues, and
can be resorbable or non-resorbable in nature. Examples of tissue
materials include hard tissues, connective tissues, demineralized
bone matrix and combinations thereof. Further examples of
resorbable materials are polylactide, polyglycolide,
tyrosine-derived polycarbonate, polyanhydride, polyorthoester,
polyphosphazene, calcium phosphate, hydroxyapatite, bioactive
glass, and combinations thereof. Further examples of non-resorbable
materials are non-reinforced polymers, carbon-reinforced polymer
composites, PEEK and PEEK composites, shape-memory alloys,
titanium, titanium alloys, cobalt chrome alloys, stainless steel,
ceramics and combinations thereof and others as well.
[0026] Any suitable osteogenetic material or composition is
contemplated for placement within chambers defined by the members
of the vertebral replacement device. Such osteogenic material
includes, for example, autograft, allograft, xenograft,
demineralized bone, synthetic and natural bone graft substitutes,
such as bioceramics and polymers, and osteoinductive factors. Where
bony material is placed within the chambers of the components of
the vertebral replacement device, the material can be pre-packed
into the hollow chambers before the device is implanted, or can be
pushed through the plurality of wall openings after the device is
in position in the spinal column. A separate carrier to hold the
materials within the chambers of the device can also be used. These
carriers can include collagen-based carriers, bioceramic materials,
such as BIOGLASS.RTM., hydroxyapatite and calcium phosphate
compositions. The carrier material can be provided in the form of a
sponge, a block, folded sheet, putty, paste, graft material or
other suitable form. Moreover, the osteogenetic compositions
contained within the vertebral replacement device can comprise an
effective amount of a bone morphogenetic protein, transforming
growth factor .beta.1, insulin-like growth factor 1,
platelet-derived growth factor, fibroblast growth factor, LIM
mineralization protein (LMP), and combinations thereof or other
therapeutic or infection resistant agent, held within a suitable
carrier material.
[0027] In FIGS. 1-3, a vertebral replacement device 10 includes a
connecting member 12, an upper member 30, and a lower member 40.
Device 10 is illustrated as having a tubular form that extends
along a longitudinal axis 11 and defines a chamber extending
therethrough along axis 11. Bone growth can occur through this
chamber for fusion between the vertebral bodies supported at each
end of device 10. It is also contemplated that device 10 can be
provided without a chamber extending therethrough. It is further
contemplated that one or more of the members 12, 30, 40 is provided
with a chamber, and that the other members are not.
[0028] Connecting member 12 includes a body 14 extending between an
upper end 19 and an opposite lower end 21. Connecting member 12
further includes an upper extension 18 and a lower extension 23.
Connecting member 12 includes an inner wall surface 13 (FIG. 5)
that defines a chamber 16 extending between and opening at the
outer ends of the extensions 18, 23. Each of the extensions 18, 23
extends outwardly from the respective end 19, 21 of body 14 and
around chamber 16. End surface 15 extends around upper extension
18, and end surface 17 extends around lower extension 23. In the
illustrated embodiment, extensions 18, 23 are threaded cylinders
integrally formed with body 14 and extending from their respective
end 19, 21. Other embodiments contemplate other forms for
extensions 18, 23. For example, extensions 18, 23 can be in the
form of externally threaded cylindrical sleeves that are separable
from body 14 and engaged thereto by, for example, threadingly
engaging internal threads along surface 13 of body 14. Other
connections between body 14 and extensions 18, 23 are also
contemplated, including friction fits, welded or fusion fits, end
to end flanged fits with screws or bolts, bayonet locks, snap rings
and the like.
[0029] The wall of body 14 includes a number of apertures 22
radially spaced about the mid-height thereof which extend through
the wall and communicate with chamber 16. Various shapes for
apertures 22 are contemplated, including circular and non-circular
shapes such as a square, diamond, oval and/or rectangular shapes,
and/or polygonal shapes. Apertures 22 can be engaged by an
instrument to rotate body 14 in situ to adjust the overall height
of device 10 while members 30, 40 are held in position by contact
with the adjacent vertebral endplates or by external means. Members
30, 40 can also be rotated about the respective extensions 18, 23
to adjust the height of device 10. Various patterns for apertures
22 are also contemplated, including, for example, random patterns,
axially spaced apertures, apertures positioned radially and axially
about the entire body 14, and combinations thereof. A body 14 with
no apertures is also contemplated.
[0030] Extensions 18, 23 can be provided with a substantially
continuous thread extending along substantially the entire length
of the corresponding extension 18, 23. Partially threaded
extensions are also contemplated. The threads threadingly engage
threads of the corresponding upper and lower members 30, 40 to
resist axial dislocation of upper member 30 and lower member 40
away from and toward connecting member 12 along axis 11. To prevent
rotation of upper and lower members 30, 40 when device 10 is
positioned in the space between vertebrae, a set screw or other
engagement member can be positioned through an aperture in the wall
of the upper and lower members 30, 40 and engage the respective
extensions 18, 23. Rotation can additionally or alternatively be
resisted by the axial compression forces on members 30, 40 by the
adjacent vertebrae, the engagement of the outer ends of members 30,
40 with the adjacent vertebral endplates, and/or by providing
locking engagement between the interfacing threads.
[0031] Referring also to FIGS. 5-6, upper and lower members 30, 40
are illustrated as being identical, although it is also
contemplated that upper member 30 and lower member 40 can be
provided with different configurations and/or sizes. Only upper
member 30 will be further described, it being understood that lower
member 40 can be provided with identical features.
[0032] Upper member 30 includes a body 32 extending between an
upper end 33 and a lower end 35. Body 32 has a height 82 between
the upper and lower ends 33, 35. Height 82 can be selected so that
upper member 30 fits within an intervertebral disc space between
adjacent vertebrae. Upper end 33 and lower end 35 can be sloped to
converge toward one another and form a height 86 opposite height
82. The sloped ends 33, 35 allow upper member 30 to restore and/or
conform to the natural inclination between the adjacent endplates
of the vertebral bodies. It is further contemplated that ends 33,
35 can be parallel to one another, or include a convex curvature.
Still other embodiments contemplate that ends 33, 35 can include
concave curvatures.
[0033] As shown in FIG. 6, body 32 has an inner wall surface 37
defining a chamber 34 that extends between and opens at ends 33,
35. A thread pattern 38 is provided along inner wall surface 37 to
threadingly engage extension 18. Thread pattern 38 can extend along
all or a portion of the height of body 32. Body 32 has an outer
surface 39 that defines a kidney-shaped cross section transverse to
longitudinal axis 11 that includes a concavely curved outer surface
portion 41 and a convexly curved outer surface portion 43. Other
cross-sectional shapes are also contemplated, including, for
example, circular cross-sections and non-circular cross-sections,
such as oval, triangular, square, rectangular, polygonal, boomerang
shaped, D-shaped, or racetrack shaped cross-sections.
[0034] In the illustrated embodiment, body 14 of connecting member
12 has a circular cross-sectional shape transverse to longitudinal
axis 11. Thus, as shown in FIG. 3, body 14 extends laterally beyond
outer surface 39 of body 32 adjacent concavely curved portion 41.
Body 14 can also be provided with the same shape as the upper and
lower members 30, 40 to provide a vertebral replacement body device
of uniform cross-sectional shape and size along its height.
[0035] Body 32 defines a number of triangular apertures 36
extending at least partially therethrough in communication with
chamber 34, and a number of circular holes 38 extending at least
partially therethrough from outer surface 39 of body 32. Holes 38
or the other holes can be threaded or otherwise sized and/or
configured for engagement with one or more insertion
instruments.
[0036] Body 32 further includes a number of bearing surfaces 60
spaced around first end 33 and bearing surfaces 62 spaced around
second end 35. Adjacent ones of each of the bearing surfaces 60 are
separated from one another by V-shaped recesses 64. Adjacent ones
of each of the bearing surfaces 62 are separated from one another
by V-shaped recesses 66. Bearing surfaces 60, 62 are planar and
provide a number of plateau-like, generally flat bearing surfaces
spaced about the respective end of body 32. Bearing surfaces 60, 62
have a trapezoidal shape as shown in FIG. 6, although other shapes
are also contemplated. It is further contemplated that each end of
body 32 could be provided with a single, continuous bearing surface
extending around chamber 34, a continuous bearing surface enclosing
or substantially enclosing chamber 34, and/or a bearing surface
that bifurcates chamber 34.
[0037] The plateau-like bearing surfaces 60, 62 provide a surface
area about the ends of body 32 for bearing support of the adjacent
vertebral endplate and to resist subsidence of body 32 into the
vertebrae. The plateau-like bearing surfaces 60, 62 provide surface
area contact between the end of body 32 and the adjacent endplate,
providing frictional resistance to body 32 sliding or twisting
relative to the adjacent vertebral endplate. In the illustrated
embodiment, bearing surfaces 60, 62 are formed by cutting body 32
through triangular apertures 36 that are radially spaced about body
32 and having their apices oriented away from the adjacent bearing
surface. Since the triangular apertures are located at the same
height about body 32, and ends 33, 35 are tapered, the depth and
width of the recesses decrease toward the reduced height side of
body 32, as shown in FIGS. 5 and 6.
[0038] Upper member 30 and lower member 40 are threadingly
connected to respective ends of connecting member 12 to provide one
embodiment vertebral replacement body device 10. Upper member 30 is
threadingly advanced over upper extension 18 so that upper
extension 18 extends into chamber 34. Lower member 40 is secured to
lower extension 23 in a similar manner. It is contemplated that
upper and lower members 30, 40 are positioned along the respective
extensions 18, 23 so that upper and lower members are aligned with
one another. For example, for upper and lower members 30, 40
provided with the kidney-shaped outer surface 39, concave surface
portions 41 can be aligned along vertebral body member 10 to
provide the desired fit in the disc space and so that the outer
ends converge toward one another, as shown in FIG. 3.
[0039] Bearing surfaces 62 at lower end 35 of upper member 30 are
spaced from end surface 15 extending about upper extension 18 of
connecting member 12. The load from the spinal column is
transmitted from upper member 30 to connecting member 12 through
the threads engaging the members to one another. The space between
the end surfaces of upper member 30 and body 12 provides additional
locations for bone growth to stabilized device 10 in the space
between vertebrae. The bearing surfaces of the lower member 40 are
similarly spaced from end surface 17 extending about lower
extension 23 of connecting member 12. As such, the end surfaces 15,
17 at the ends of body 14 and the adjacent bearing surfaces of the
upper and lower members 30, 40 do not interdigitate or engage.
Other embodiments contemplate that the ends of members 30, 40 can
bear against the adjacent end surface 15, 17 of body 14 if the
respective upper and lower members 30, 40 are adjusted along the
corresponding extension 18, 23 to provide such contact.
[0040] Device 10 can be used to replace a vertebra that has been
removed from the spinal column segment using known techniques.
Device 10 is assembled by securing upper member 30 to one end of
connecting member 12 and securing lower member 40 to the other end
of connecting member 12. This provides a vertebral replacement
device 10 that has an overall height that is adjustable to provide
the desired fit in the space between the vertebrae.
[0041] Vertebral replacement device 10 can be placed between a pair
of intact vertebrae remaining after removal of vertebra 72.
Replacement of more than one vertebra is also contemplated. A
stabilization construct can be engaged to and extend between the
intact vertebrae to support and stabilize the spinal column
segment. The stabilization construct can be a rod system, plate
system and/or artificial ligament system, for example. It is
further contemplated that stabilization construct could be attached
to any portion of the remaining vertebrae, including the anterior,
antero-lateral, lateral, postero-lateral and/or posterior
portions.
[0042] It is also contemplated that the upper and lower ends of
upper and lower members 30, 40 could be provided with the same or
differing angles of inclination. It is further contemplated that
device 10 can comprise a kit having a number of upper members 30
and lower members 40 of various sizes, inclinations and/or heights
82, 84. A kit could also include a number of connecting members 12
of various sizes and lengths of extensions 18, 23. Such a kit would
provide the surgeon flexibility in selecting the appropriately size
and height for members of a device 10 based on conditions
encountered in surgery. Providing extensions 18, 23 with opposing
left and right hand threads allows connecting member 12 of device
10 can act as a turnbuckle to adjust the spacing between members
30, 40 in situ. It is also contemplated that extensions 18, 23 can
be provided with threads turning in the same direction.
[0043] It is contemplated that upper or lower members 30, 40 can,
when separated from connecting member 12, be positioned in a disc
space between adjacent vertebrae. The heights 82, 84 between ends
33, 35 can thus be sized accordingly. Upper and lower members 30,
40 can be sized and/or shaped for insertion as a single member in a
disc space that provides bilateral support of the adjacent
vertebrae, or sized for insertion in combination with a second
member in a disc space to provide bilateral support. Insertion of
members 30, 40 into a disc space can be conducted via any one or
combination of approaches, including anterior, posterior,
posterior-lateral, anterior-oblique and lateral approaches. Members
30, 40 can be positioned into the disc space through a retractor
sleeve in minimally invasive procedures, or through retracted skin
and tissue in open surgical techniques.
[0044] It is also contemplated that connecting member 12 could be
provided with one end configured to bear against a vertebral
endplate, and that only one of the upper and lower members 30, 40
is engaged to the other end of connecting member 12. The assembled
device could then be placed between adjacent vertebrae with an end
of connecting member 12 and an end of the selected upper or lower
member 30, 40 in contact with the adjacent vertebral endplates.
[0045] Referring now to FIG. 7, another embodiment vertebral
replacement device 110 includes connecting member 112 and upper and
lower members 130, 140 threadingly engaged to extensions 118, 123.
Connecting member 112 is similar to connecting member 12, but
includes a body 114 having a height 113 minimized between
extensions 118, 123. It is also contemplated that connecting member
112 can be provided without body 114, but rather as a cylinder
extending between and having the same diameter as extensions 18, 23
to accommodate apertures 122. The thread pattern can extend along
the entire length of the connecting member, are along a portion of
the length adjacent the opposite ends thereof.
[0046] Upper and lower members 130, 140 can be identical, and are
described with reference to upper member 130. Upper member 130
includes a body 132 extending between upper and lower ends 133,
135. Bearing surface 160 at upper end 133 extends substantially
across the entire width of body 132 and is convexly curved to
conform to the vertebral endplate anatomy against which it is
positioned. Bearing surface 160 includes a plurality of holes 161
to accommodate bone growth therethrough, although a solid bearing
surface 160 is also contemplated. Holes 161 can communicate with a
chamber extending into body 132, and also a chamber extending
through connecting member 112.
[0047] Lower end 135 includes bearing surface 162 extending about a
chamber opening at end 135. Bearing surface 162 is substantially
continuous, although other surface patterns discussed herein are
also contemplated. The chamber of body 132 receives extension 118,
and can include threads extending therein from the inner surface of
body 132 to threadingly engage extension 118. Upper and lower
members 130, 140 can thus be adjustably engaged and axially
restrained relative to connecting member 112 for use in corpectomy
procedures. It is further contemplated that upper and lower members
130, 140 can be used without connecting member 112 in disc space
replacement procedures.
[0048] Referring now to FIG. 8, there is shown vertebral
replacement device 210. Vertebral replacement device 210 includes a
connecting member 212, which is identical to connecting member 112.
An upper member 230 and a lower member 240 are threadingly engaged
to respective ones of the extensions 218, 223 of connecting member
212. Upper and lower members 230, 240 can be identical to one
another, and will be described with reference to upper member
230.
[0049] As further shown in FIG. 9, upper member 230 includes a body
232 having a chamber 234. Chamber 234 can extend completely or
partially through the upper and lower ends 233, 235 of body 232.
Chamber 234 opens toward lower end 235 to receive extension 218
therein. Body 232 includes an inner surface 237 defining chamber
234. Chamber 234 includes a non-circular shape transversely to the
longitudinal axis of device 210, providing additional area for
receipt and placement of bone growth material in chamber 234.
Chamber 234 also provides open area about extension 218 in chamber
234, facilitating incorporation of connecting member 212 in the
fusion of the adjacent vertebrae.
[0050] Inner wall surface 234 includes threaded portions 238 to
threadingly engage extensions 218. Threaded portions 238 extend
along only a portion of inner wall surface 237 that is contactable
by extension 218, while the remainder of inner wall surface 237 can
remain unthreaded.
[0051] Body 232 includes an outer surface 239 forming a D-shape
having a convexly curved wall 241, an opposite linear wall 243, and
parallel linear side walls 245, 247. Inner wall surface 237 defines
a square shaped chamber 234. Other shapes for outer surface 239 and
inner surface 237 are also contemplated, including circular and
non-circular shapes, such as oval, square, kidney, boomerang,
rectangular, polygonal, triangular, and various combinations of
curved and linear wall segments.
[0052] Referring to FIG. 10, another embodiment vertebral
replacement device 310 is shown. Vertebral replacement device 310
includes a sub-assembly 360 that comprises a connecting member 312
and upper member 330 and a lower member 340. Connecting member 312,
upper member 330 and lower member 340 can be similar to the
embodiments discussed above, and provide a height adjustable
sub-assembly 360 by threaded engagement of members 330, 340 with
extensions 318, 323 of connecting member 312.
[0053] Vertebral replacement device 310 further includes an upper
spacer 370 and a lower spacer 380. Spacer 370 includes a body 372
extending between an upper end 375 and a lower end 376. A lower
extension 378 extends downwardly from lower end 376 towards upper
member 330. Similarly, lower spacer 380 includes a body 382
extending between an upper end 385 and a lower end 386. An upper
extension 388 extends upwardly from upper end 385 towards lower
member 330.
[0054] Referring further to FIGS. 11-12, each of the spacers 370,
380 include an engaging member in extensions 378, 388,
respectively, such as shown with engaging member 390 of lower
spacer 380. Extension 388 is positionable in the chamber (not
shown) of lower member 340 and engages lower member 340 to axially
secure lower spacer 380 thereto. The engaging member 379 of
extension 378 similarly engages upper member 330 in chamber
334.
[0055] Engaging members 379, 390 secure upper spacer 370 and lower
spacer 380 to respective ends of upper member 330 and lower member
340, resisting axial dislocation of spacers 370, 380 away from the
respective upper and lower members 330, 340 along axis 311.
Engaging members 379, 390 can also resist axial rotation of spacers
370, 380 relative to the respective upper and lower members 330,
340 about axis 311. Other embodiments contemplate that more than
one engaging member 379, 390 can be provided in the wall of one or
both of the extensions 378, 388.
[0056] Extensions 378, 388 are telescopingly received in upper and
lower members 330, 340 until the adjacent ends bear against one
another. Extensions 378, 388 can also resist lateral displacement
of spacers 370, 380 relative to the engaged upper and lower member
330, 340 and also rotational displacement if provided with a
non-circular interface therebetween.
[0057] As shown in FIGS. 11 and 12, engaging members 379, 390
include a projection or engaging portion 396 and a stem 392
connected or integrally formed with adjacent end of spacers 370,
380. Stem 392 has a reduced thickness to allow engaging members
379, 390 to deflect inwardly in response to a force applied to
engaging portion 396. Engaging portion 396 projects outwardly from
stem 392 and has a triangular shape tapering in thickness and width
from an engaging surface 398 to an opposite outer end 394. In the
illustrated embodiment, the triangular shaped engaging portion 396
fits within a triangular shaped recess 333 of the upper and lower
members 330, 340. Recess 333 can open toward chamber 334, and can
extend partially through the wall of member 330, or can extend
completely through the wall and comprise a portion of an aperture
thereof.
[0058] Other configurations for engaging members 379, 390 are also
contemplated. For example, engaging members 379, 390 can be
provided with an engaging portion 396 in the form of a partially
spherical or rounded nub, a receptacle, rectangular or polygonal
shaped tab or projection. Engaging portion 396 can have any size
and shape that can be received in an aperture, recess and/or space
opening in the inner wall surface of upper member 330 and lower
member 340. In one embodiment, engaging portion 396 fits between
adjacent thread turns on the inner wall surface of upper member 330
and lower member 340. Engaging members 379, 390 can also be in the
form of a snap ring, collet, bayonet lock, or surface irregularity
that resists axial movement of the spacer 370, 380 away from the
engaged upper member 330 and lower member 340 along axis 311.
[0059] When secured to the respective upper and lower members 330,
340, spacers 370, 380 can bear against the adjacent end surfaces of
the upper and lower member 330, 340 to provide axial restraint in
compression. Engaging members 379, 390 provide axial restraint in
tension away from the adjacent upper and lower member 330, 340.
Torsional and lateral restraint of spacer members 370, 380 is
provided by the interface between extensions 378, 388 and the inner
wall of the respective coupling member 330, 340 to which spacer
370, 380 is engaged.
[0060] Spacer members 370 can be provided in a kit of a number of
spacer members of various heights to provide further adjustment of
the overall height of device 310. It is further contemplated that
the spacer members can be used in isolation in a disc space as a
disc replacement device for interbody fusion procedures, or
positioned in side by-side relation with one another in a disc
space for interbody fusion procedures. Spacers 370, 380 can be
provided in any size, shape, height and end surface configuration
as discussed above for the upper and lower members discussed
herein.
[0061] In another embodiment, it is contemplated that upper and
lower members 330, 340 are provided with an extension positionable
in the chamber of the adjacent upper and lower spacer 370, 380. The
extensions of the upper and lower members 330, 340 can include a
flexible engaging member to engage an aperture, recess or other
space in the respective upper and lower spacers 370, 380 in the
manner discussed above with respect to extensions 378, 388 and
engaging members 379, 390.
[0062] In FIG. 13 there is provided an alternate embodiment
vertebral replacement device 410. Vertebral replacement device 410
includes a height-adjustable sub-assembly 460 including first disc
replacement or upper member 430 and second disc replacement or
lower member 440 adjustably engaged at opposite ends of a vertebral
body or connecting member 412. Upper spacer 470 is engageable to
upper member 430, and lower spacer 480 is engageable to lower
member.
[0063] A first coupling member 450 includes a flexible engaging
member 452 at one end thereof and a second flexible engaging member
454 at a second end thereof. Engaging members 452, 454 can be
similar to engaging members 379, 390 discussed above. In the
illustrated embodiment, engaging members 452, 454 are integrally
formed in a wall of coupling member 450 an are resiliently
deflectable inwardly as spacer 470 and upper member 430 are
positioned thereover. Engaging members 452, 454 engage a recess or
other structure in the corresponding spacer 470 and upper member
430 to axially constrain spacer member 470 to upper member 430. A
second coupling member 490 is provided with engaging members 492,
494 to similarly secure spacer 480 to lower member 440.
[0064] Coupling members 450, 490 are illustrated in the form of
cylindrical sleeves with a central passage to allow bone growth
therethrough. Coupling members 450, 490 can be provided with
non-circular cross-sections to resist rotation of members 430, 440
and spacers 470, 480 relative thereto. It is further contemplated
that coupling members 450, 490 can be provided with a solid body,
or a body including a number of passages extending therethrough. In
another form, coupling members 450, 490 are comprised of material
facilitating bone growth. Coupling members 450, 490 can include one
or more projections formed on an outer wall surface thereof to
engage recesses in the inner wall surfaces of members 330, 340 and
spacers 370, 380.
[0065] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character. All
changes and modifications that come within the spirit of the
invention are desired to be protected.
* * * * *