U.S. patent application number 10/337001 was filed with the patent office on 2003-08-07 for bone support assembly.
Invention is credited to Paul, Kamaljit S..
Application Number | 20030149434 10/337001 |
Document ID | / |
Family ID | 26943255 |
Filed Date | 2003-08-07 |
United States Patent
Application |
20030149434 |
Kind Code |
A1 |
Paul, Kamaljit S. |
August 7, 2003 |
Bone support assembly
Abstract
A bone support assembly comprising a support plate, bone
fasteners, and a bone fastener cover assembly. The support plate
comprises a fixed base portion comprising base apertures, and a
slot portion comprising slot-shaped apertures. The bone fasteners
are disposed in ones of the base apertures and the slot-shaped
apertures, the bone fasteners and the support plate, in
combination, being adapted and configured for holding the support
plate to bone material. The bone fastener cover assembly comprises
a cover plate, and at least one cover plate fastener effective to
fasten the cover plate to the support plate. The cover plate and
support plate, in combination, accommodate both longitudinal and
transverse sliding movement of the cover plate along the top
surface of the support plate to thereby cover and uncover ones of
the apertures, having bone fasteners therein, while the cover plate
is attached to the support plate.
Inventors: |
Paul, Kamaljit S.; (Oshkosh,
WI) |
Correspondence
Address: |
WILHELM LAW SERVICE, S.C.
100 W LAWRENCE ST
THIRD FLOOR
APPLETON
WI
54911
|
Family ID: |
26943255 |
Appl. No.: |
10/337001 |
Filed: |
January 6, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10337001 |
Jan 6, 2003 |
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09838646 |
Apr 19, 2001 |
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6503250 |
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60253437 |
Nov 28, 2000 |
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Current U.S.
Class: |
606/71 ; 606/280;
606/281; 606/296 |
Current CPC
Class: |
A61B 17/8042 20130101;
A61B 17/7059 20130101 |
Class at
Publication: |
606/71 ;
606/61 |
International
Class: |
A61B 017/70; A61B
017/80 |
Claims
Having thus described the invention, what is claimed is:
1. A bone support plate for use in a bone support assembly, said
bone support plate comprising: (a) a top surface; (b) a bottom
surface opposite the top surface and adapted to engage bone
structure of a user; (c) a fixed base portion, having first and
second apertures extending therethrough, from the top surface to
the bottom surface, for receiving bone fasteners therethrough; (d)
a first base cover plate recess in the top surface at said fixed
base portion for receiving a base cover plate thereonto and
accommodating sliding movement of such base cover plate to impose
and withdraw at least partial obstruction of the first and second
apertures; (e) a slot portion, having at least third and fourth
apertures extending therethrough, from the top surface to the
bottom surface, for receiving bone fasteners therethrough; and (f)
a second settle cover plate recess in the top surface at said slot
portion for receiving a settle cover plate thereonto and
accommodating sliding movement of such settle cover plate to impose
and withdraw at least partial obstruction of the third and fourth
apertures.
2. A bone support plate as in claim 1 wherein said bone support
plate is designed and configured to enable bidirectional sliding
movement of a base cover plate connected thereto.
3. A bone support plate as in claim 1 wherein said bone support
plate is designed and configured to enable bidirectional sliding
movement of a settle cover plate connected thereto.
4. A bone support plate as in claim 1 wherein said bone support
plate comprises a base cover plate fastener aperture extending from
the first base cover plate recess toward the bottom surface of said
bone support plate, for receiving a base cover plate fastener.
5. A bone support plate as in claim 1 wherein said bone support
plate comprises a settle cover plate fastener aperture extending
from the second settle cover plate recess toward the bottom surface
of said bone support plate, for receiving a settle cover plate
fastener.
6. A bone support plate as in claim 1 wherein at least a portion of
said bottom surface of said support plate comprises a texturized
surface, said texturized surface enhancing engagement of said
support plate to the bone structure.
7. A bone support plate as in claim 1, said at least third and
fourth apertures of said slot portion being longitudinally
slot-shaped, with respect to a longitudinal axis of said support
plate, to enable respective bone fasteners to be inserted into
respective said at least third and fourth apertures such that the
slot-shaped apertures accommodate movement of the bone support
plate with respect to such bone fasteners.
8. A bone support assembly for support of bone structure, said bone
support assembly comprising: (a) a support plate comprising a top
surface, a bottom surface adapted to engage such bone structure, a
fixed base portion, and a slot portion, said fixed base portion
comprising base apertures, said slot portion comprising slot-shaped
apertures; (b) bone fasteners disposed in ones of the base
apertures and the slot-shaped apertures, said bone fasteners and
said support plate, in combination, being adapted and configured
for holding said support plate to bone material; and (c) a bone
fastener cover assembly, said bone fastener cover assembly
comprising a cover plate, and at least one cover plate fastener
effective to fasten said cover plate to said support plate, said at
least one cover plate and said support plate, in combination,
accommodating both longitudinal and transverse sliding movement of
said cover plate with respect to said support plate, to thereby
cover and uncover ones of said bone fasteners while said cover
plate is attached to said support plate, including uncovering one
of a pair of bone fasteners arranged in side-by-side relationship
along the longitudinal axis of said support plate, while relatively
covering the other of such pair of bone fasteners.
9. A bone support assembly as in claim 8 wherein at least a portion
of said bottom surface of said support plate comprises a texturized
surface, said texturized surface enhancing engagement of said
support plate to bone material.
10. A bone support assembly as in claim 8 wherein said cover plate
of said bone fastener cover assembly simultaneously covers, at
least in part, said bone fasteners in at least 4 slot-shaped
apertures of said support plate, where one or both longitudinal and
transverse movement of said cover plate tends to simultaneously
cover a said bone fastener in at least one aperture while
uncovering another said bone fastener in another aperture, whereby
at no time are said bone fasteners in all apertures uncovered.
11. A bone support assembly for support of bone structure, said
bone support assembly comprising: (a) a support plate comprising a
top surface, a bottom surface adapted to engage such bone
structure, a fixed base portion, and a slot portion, said fixed
base portion comprising base apertures, said slot portion
comprising slot-shaped apertures; (b) bone fasteners disposed in
ones of the base apertures and the slot-shaped apertures, said bone
fasteners and said support plate, in combination, being adapted and
configured for holding said support plate to bone material; (c) a
base portion cover assembly disposed at said fixed base portion;
and (d) a slot portion cover assembly disposed at said slot
portion.
12. A bone support assembly as in claim 11, said base portion cover
assembly comprising a base cover plate having an upper surface and
a lower surface, at least one base cover plate fastener, and at
least one base cover plate aperture spanning from the upper surface
of said base cover plate toward the lower surface of said base
cover plate.
13. A bone support assembly as in claim 12, size of said at least
one base cover plate aperture being greater than a corresponding
size of said at least one base cover plate fastener by a first
dimension greater than or substantially equal to that amount of
bidirectional movement of said base cover plate about said base
cover plate fastener relative to said support plate necessary to
gain fastening access to at least one said bone fastener of said
support plate while prohibiting fastening access to at least
another said bone fastener, whereby at no time are all bone
fasteners accessible for fastening to said bone structure.
14. A bone support assembly as in claim 12, said at least one base
cover plate aperture comprising an aperture wall, wherein an upper
portion of said aperture wall comprises an inwardly-tapered
frustoconical configuration extending inwardly toward the lower
surface of said base cover plate.
15. A bone support assembly as in claim 11, said base portion cover
assembly comprising a base cover plate, said base cover plate
overlapping a portion of at least one said bone fastener in at
least one of said base apertures of said support plate.
16. A bone support assembly as in claim 15, including a slot in at
least one of said base cover plate and said support plate,
accommodating sliding of said base cover plate into overlying
relationship with first ones of said bone fasteners, and out of
overlying relationship with second ones of said bone fasteners.
17. A bone support assembly as in claim 11 wherein said base cover
plate and said support plate, in combination, are designed and
configured to enable bidirectional adjustment of said base cover
plate, with respect to said support plate, while maintaining said
support plate connected to said base cover plate.
18. A bone support assembly as in claim 11, said slot portion cover
assembly comprising a settle cover plate having a superior surface
and an inferior surface, at least one settle cover plate aperture
spanning from said superior surface to said inferior surface of
said settle cover plate, and at least one settle cover plate
fastener in said at least one settle cover plate aperture.
19. A bone support assembly as in claim 12, said slot portion cover
assembly comprising a settle cover plate having a superior surface
and an inferior surface, at least one settle cover plate aperture
spanning from said superior surface to said inferior surface of
said settle cover plate, and at least one settle cover plate
fastener in said at least one settle cover plate aperture.
20. A bone support assembly as in claim 11, said at least one
settle cover plate aperture comprising an aperture wall, wherein an
upper portion of said aperture wall comprises an inwardly-tapered
frustoconical configuration adjacent the superior surface of said
settle cover plate and extending toward the inferior surface of
said settle cover plate.
21. A bone support assembly as in claim 11, said slot portion cover
assembly comprising a settle cover plate, said settle cover plate
overlapping a portion of at least one said bone fastener in at
least one said slot-shaped aperture of said support plate.
22. A bone support assembly as in claim 21 wherein said settle
cover plate and said support plate are, in combination, designed
and configured to enable bidirectional adjustment of said settle
cover plate, with respect to said support plate, while maintaining
said support plate connected to said settle cover plate.
23. A bone support assembly as in claim 11 wherein at least a
portion of said bottom surface of said support plate comprises a
texturized surface, said texturized surface enhancing engagement of
said support plate to bone material.
24. A bone support assembly as in claim 11 wherein the slot-shaped
apertures are designed and configured to enable respective bone
fasteners to be inserted into respective said slot-shaped apertures
such that the slot-shaped apertures accommodate movement of the
bone support plate with respect to the bone fasteners.
25. A bone support assembly as in claim 21 wherein said settle
cover plate can simultaneously cover, at least in part, said bone
fasteners in at least 4 slot-shaped apertures of said slot portion,
where one or both longitudinal and transverse movement of said
settle cover plate tends to simultaneously cover a said bone
fastener in at least one said aperture while uncovering another
said bone fastener in another said aperture, whereby at no time are
all bone fasteners in all apertures uncovered.
26. A bone support assembly as in claim 22 wherein said settle
cover plate can simultaneously cover, at least in part, said bone
fasteners in at least 4 slot-shaped apertures of said slot portion,
where one or both longitudinal and transverse movement of said
settle cover plate tends to simultaneously cover a said bone
fastener in at least one said aperture while uncovering another
said bone fastener in another said aperture, whereby at no time are
all bone fasteners in all apertures uncovered.
27. A method of mounting a support to bone structure, the method
comprising: (a) providing a bone support assembly comprising (i) a
support plate adapted to support bone structure, the support plate
comprising a fixed base portion having base apertures, and a slot
portion having slot-shaped apertures, (ii) bone fasteners in ones
of the base apertures and the slot-shaped apertures, and (iii) a
cover plate disposed over a top surface of the support plate; (b)
moving the bone support assembly into position over bone structure
to be supported; (c) sliding the cover plate, as necessary, away
from a position over ones but not all of the bone fasteners thus to
expose such fasteners for fastening, and fastening the bone
fasteners to the bone structure; and (d) sliding the cover plate at
least partially over the bone fasteners so fastened and tightening
the cover plate to the support plate thereby to prevent movement of
the cover plate with respect to the fastened bone fasteners and
correspondingly preventing extraction of the fastened bone
fasteners from the bone structure.
28. A method of mounting a support to bone structure as in claim
27, the cover plate being disposed over the base apertures at the
fixed base portion, the method further including (e) providing a
settle plate over a second portion of the top surface of the
support plate at the slot portion; (f) sliding the settle plate
away from the position over additional respective ones of the bone
fasteners disposed in the slot-shaped apertures, and fastening the
respective bone fasteners, in the slot-shaped apertures, to the
bone structure; and (f) sliding the settle plate at least partially
over the respective fastened bone fasteners and tightening the
settle plate to the support plate thereby to prevent movement of
the settle plate, and correspondingly preventing extraction of the
fastened bone fasteners.
29. A method of stabilizing bone structure as in claim 38,
including using the settle plate to simultaneously cover, at least
in part, the bone fasteners in each of at least 4 slot-shaped
apertures of the slot portion, where one or both longitudinal and
transverse movement of the settle plate tends to simultaneously
cover a respective bone fastener in at least one aperture while
uncovering another respective bone fastener in another aperture,
whereby at no time are all bone fasteners in all apertures
uncovered.
Description
BACKGROUND
[0001] The present invention relates to devices for the fixation
and/or support of bones. In particular, the present invention
relates to a plate for the fixation and/or support of bones of the
spinal column. The plate of the present invention has particular
application in situations where compressional or "settling" forces,
as well as torsional and flexing forces, of "fixed" vertebrae on a
spinal plate cause significant stressing and potential failure of
the spinal plate and/or plate components.
[0002] Vertebral fixation has become a common approach to treating
spinal disorders, fractures, and for fusion of vertebrae at the
time such fixation is instituted. Namely, one or more vertebrae are
fixed in position relative to one or more other vertebrae above
and/or below the vertebrae to be fixed. Generally, a spinal plate
is the device of choice used for mechanically supporting such
vertebral fixation. A typical spinal plate includes a plate having
a plurality of apertures therethrough. A corresponding plurality of
fasteners, i.e., bone screws, are generally positioned into and
through respective apertures of the plate to secure the spinal
plate to a bone, such as two respective upper and lower supporting
adjacent spinal vertebrae. The screws are fastened to the
respective support vertebrae to secure the spinal plate to the
respective vertebrae. In general, such plate and screw assemblies
can be utilized, generally, for anterior fixation of the spine for
cervical, lumbar, and/or thoracic fixation.
[0003] The basis of anterior fixation or plating is to approach the
spine from an anterior or anterio-lateral approach, and use the
screws to solidly mount the spinal plate to the affected vertebrae.
Often, in addition to the application of a spinal plate, graft
material may be combined in attempt to permanently fuse together
adjacent vertebrae. The graft material can consist of bone grafts
obtained from bones of the recipient or another individual.
[0004] A common problem associated with the use of such spinal
plates is the tendency of the bone screws to "back out" or pull
away from the bone into which they are fixed. This problem occurs,
primarily, due to the normal torsional and bending motions of the
body and spine. This is a particularly important problem because as
the screws become loose and pull away from the bone, the heads of
the screws can rise above the surface of the spinal plate and,
possibly, even work their way completely out of the bone. While
this condition can cause extreme discomfort for the recipient, this
condition can also create a number of potentially serious
physiological problems given the significant amount of nervous and
vascular structures associated at or near the potential locations
of anterior spinal plate fixations.
[0005] A number of designs have been proposed in attempts to
prevent screws from pulling away from the bone and/or to prevent
the screws from backing out or pulling away from the surface of the
spinal plate. Such mechanisms used to prevent bone screws from
pulling out of bones include cams which engage and lock the screws,
and the use of expanding head screws which expand outwardly when
adequate force is applied thereto to engage the holes in the spinal
plate. All of these designs have detriments including potential for
breakage or requiring particular precision and alignment in their
application in order to work correctly. Additionally, loose
components and accessories of spinal plates which address the
"backing-out" problem can get dropped and/or misplaced while the
vertebral fixation surgical procedure is taking place, prolonging
and complicating the procedure as well as creating substantial risk
of harm to the recipient.
[0006] Yet another common problem associated with the use of such
spinal plates is the tendency of the vertebrae being "fixed" to
settle after spinal plate insertion adding compression forces to
the above-listed forces which cause the bone screws to "back out"
or pull away from the bone into which they were fixed. Zdeblick et
al. (U.S. Pat. No. 5,324,290) attempted to address the problem of
compression forces in the context of treating vertebral burst
fractures, but fails to provide any functional means to prevent the
screws pulling away as a result of torsional and flexing
forces.
[0007] Therefore, it is an object of the invention to provide bone
fixation apparatus which provides rigid bone-to-bone fixation
and/or support, such as e.g. adjacent or second adjacent vertebrae,
while allowing post-procedural compression between the respective
bones.
[0008] It is another object of the invention to provide bone
fixation apparatus which affords substantial protection against
pulling away of affixing components which may result from torsional
movement, flexing movement, or stress and/or dynamic load sharing
of the vertebrae, thereby enhancing the bone rebuilding
process.
[0009] It is yet another object of the invention to provide bone
fixation apparatus which attenuates application of stress on the
apparatus and affixing components. It is a further object of the
invention to provide bone fixation apparatus comprising a support
plate and fixation components, and fixation component support which
reinforces the fixation components thus to prevent the fixations
components from backing out of the support plate.
[0010] It is yet a further object of the invention to provide bone
fixation apparatus which can be pre-assembled as a loose assembly
such that no loose assembly parts or inter-procedural apparatus
need by assembled to the assembly during installation of such bone
fixation apparatus in a recipient.
SUMMARY
[0011] In a first family of embodiments, the invention comprehends
a bone support plate for use in a bone support assembly. The bone
support plate comprises a top surface, a bottom surface opposite
the top surface and adapted to engage bone structure of a user; a
fixed base portion, having first and second apertures extending
therethrough, from the top surface to the bottom surface, for
receiving bone fasteners therethrough, and a slot portion, having
at least third and fourth apertures extending therethrough, from
the top surface to the bottom surface, for receiving bone fasteners
therethrough. A first base cover plate recess is disposed in the
top surface at the fixed base portion for receiving a base cover
plate thereonto and accommodating sliding movement of such base
cover plate to impose and withdraw at least partial obstruction of
the first and second apertures. Similarly, a second settle cover
plate recess is disposed in the top surface at the slot portion for
receiving a settle cover plate thereonto and accommodating sliding
movement of such settle cover plate to impose and withdraw at least
partial obstruction of the third and fourth apertures.
[0012] In preferred embodiments, the bone support plate is designed
and configured to enable bidirectional sliding movement of a base
cover plate connected thereto, wherein the bidirectional sliding
movement is in substantial alignment with the top surface of the
bone support plate.
[0013] Preferably, the bone support plate is designed and
configured to enable bidirectional sliding movement of a settle
cover plate connected thereto, wherein the bidirectional sliding
movement is in substantial alignment with the top surface of the
bone support plate.
[0014] In some embodiments, the bone support plate comprises a base
cover plate fastener aperture extending therethrough, from the
first base cover plate recess to the bottom surface of the bone
support plate, for receiving a base cover plate fastener
therethrough.
[0015] In some embodiments, the bone support plate comprises a
settle cover plate fastener aperture extending therethrough, from
the second settle cover plate recess to the bottom surface of the
bone support plate, for receiving a settle cover plate fastener
therethrough.
[0016] In some embodiments, at least a portion of the bottom
surface of the support plate comprises a texturized surface, the
texturized surface enhancing engagement of the support plate to the
bone structure.
[0017] The apertures of the slot portion are preferably
longitudinally slot-shaped, with respect to a longitudinal axis of
the support plate, to enable respective bone fasteners to be
inserted into the respective apertures such that the slot-shaped
apertures accommodate movement of the bone support plate with
respect to the bone fasteners.
[0018] In preferred embodiments, the support plate is curved to
conform the support plate to the curvature of corresponding
vertebrae.
[0019] In a second family of embodiments, the invention comprehends
a bone support assembly comprising a support plate, bone fasteners,
and a bone fastener cover assembly. The support plate comprises a
top surface, a bottom surface adapted to engage such bone
structure, a fixed base portion comprising base apertures, and a
slot portion comprising slot-shaped apertures. The bone fasteners
are disposed in ones of the base apertures and the slot-shaped
apertures, the bone fasteners and the support plate, in
combination, being adapted and configured for holding the support
plate to bone material. The bone fastener cover assembly comprises
a cover plate, and at least one cover plate fastener effective to
fasten the cover plate to the support plate. The at least one cover
plate and the support plate, in combination, accommodate both
longitudinal and transverse sliding movement of the cover plate
along the top surface of the support plate, with respect to a
longitudinal axis of the support plate, to thereby cover and
uncover ones of the bone fasteners while the cover plate is
attached to the support plate, including uncovering one of a pair
of bone fasteners arranged in side-by-side relationship along the
longitudinal axis of the support plate, while relatively covering
the other of such pair of bone fasteners.
[0020] In some embodiments, at least a portion of the bottom
surface of the support plate comprises a texturized surface, the
texturized surface enhancing engagement of the support plate to
bone material.
[0021] In preferred embodiments, the slot-shaped apertures are
designed and configured to receive respective ones of the bone
fasteners into respective slot-shaped apertures such that ones of
the bone fasteners can move about freely within the apertures.
[0022] Preferably, the cover plate of the bone fastener cover
assembly simultaneously covers, at least in part, bone fasteners in
at least 4 slot-shaped apertures of the support plate, where one or
both longitudinal and transverse movement of the cover plate tends
to simultaneously cover a bone fastener in at least one aperture
while uncovering another bone fastener in another aperture, whereby
at no time are the bone fasteners in all apertures uncovered.
[0023] In a third family of embodiments, the bone support assembly
comprises a support plate, bone fasteners, a base portion cover
assembly disposed at the fixed base portion, and a slot portion
cover assembly disposed at the slot portion.
[0024] In preferred embodiments, the base portion cover assembly
comprises a base cover plate having an upper surface and a lower
surface, at least one base cover plate fastener, and at least one
base cover plate aperture spanning from the upper surface of the
base cover plate to the lower surface of the base cover plate.
[0025] Preferably, the size of the at least one base cover plate
aperture is greater than a corresponding size of at least one base
cover plate fastener by a first dimension greater than or
substantially equal to that amount of bidirectional movement of the
base cover plate about the base cover plate fastener relative to
the support plate necessary to gain fastening access to at least
one bone fastener of the support plate while prohibiting fastening
access to at least another bone fastener, whereby at no time are
all bone fasteners accessible for fastening to the bone
structure.
[0026] In some embodiments, the at least one base cover plate
aperture comprises an aperture wall, wherein an upper portion of
the aperture wall comprises an inwardly-tapered frustoconical
configuration extending inwardly toward the lower surface of the
base cover plate.
[0027] In preferred embodiments, the connection of the base portion
cover assembly to the support plate is achieved by inserting the
base cover plate fastener through the base cover plate aperture of
the base cover plate and into a first base cover plate fastener
aperture in the support plate, at least a portion of a wall of the
first base cover plate fastener aperture being designed and
configured to create a locking engagement relationship with the
base cover plate fastener, the locking engagement relationship
effectively preventing autonomous backing out of the base cover
plate fastener from the first base cover plate fastener
aperture.
[0028] In some embodiments, the locking engagement relationship is
formed by the base cover plate fastener, having threading of a
first wider pitch, being engaged against the wall of the first base
cover plate fastener aperture, having threading of a second
narrower pitch, whereby communication between the first and second
threadings prevents autonomous backing out of the base cover plate
fastener.
[0029] In other embodiments, the locking engagement relationship is
formed by the base cover plate fastener, having threading, being
engaged against the wall of the first base cover plate fastener
aperture, comprising a shim or lock-ring having cooperative
threading to that of at least a portion of the base cover plate
fastener, whereby communication between the base cover plate
fastener and the shim or lock-ring of the wall of the first base
cover plate fastener aperture prevents autonomous backing out of
the base cover plate fastener.
[0030] Preferably, the base cover plate overlaps a portion of at
least one bone fastener in at least one of the base apertures of
the support plate.
[0031] In preferred embodiments, the bone support assembly includes
a slot in at least one of the base cover plate and the support
plate, accommodating sliding of the base cover plate into overlying
relationship with first ones of the bone fasteners, and out of
overlying relationship with second ones of the bone fasteners.
[0032] In preferred embodiments, the base cover plate and the
support plate, in combination, are designed and configured to
enable bidirectional adjustment of the base cover plate, with
respect to the support plate, while maintaining the support plate
connected to the base cover plate.
[0033] The slot portion cover assembly preferably comprises a
settle cover plate having a superior surface and an inferior
surface, at least one settle cover plate fastener, and at least one
settle cover plate aperture spanning from the superior surface to
the inferior surface of the settle cover plate.
[0034] In some embodiments, the at least one settle cover plate
aperture comprises an aperture wall, wherein an upper portion of
the aperture wall comprises an inwardly-tapered frustoconical
configuration adjacent the superior surface of the settle cover
plate and extending toward the inferior surface of the settle cover
plate.
[0035] In preferred embodiments, the connection of the slot portion
cover assembly to the support plate is achieved by inserting the
settle cover plate fastener through the settle cover plate aperture
of the settle cover plate, from the superior surface to the
inferior surface, and into a second settle cover plate fastener
aperture in the support plate, at least a portion of a wall of the
second settle cover plate fastener aperture being designed and
configured to create a locking engagement relationship with the
settle cover plate fastener, the locking engagement relationship
effectively preventing autonomous backing out of the settle cover
plate fastener from the second settle cover plate fastener
aperture.
[0036] In some embodiment, the locking engagement relationship is
formed by the settle cover plate fastener, having threading of a
first pitch, being engaged into the second settle cover plate
fastener aperture, having threading of a second pitch, whereby
friction between first and second threadings prevents autonomous
backing out of the settle cover plate fastener.
[0037] In other embodiments, the locking engagement relationship is
formed between the settle cover plate fastener and a shim in the
second settle cover plate fastener aperture, wherein the shim has
cooperative threading to that of the settle cover plate fastener,
whereby tension forces between the settle cover plate fastener and
the shim of the second settle cover plate fastener aperture
prevents autonomous backing out of the settle cover plate
fastener.
[0038] The settle cover plate preferably overlaps a portion of at
least one bone fastener in at least one slot-shaped aperture of the
support plate.
[0039] In preferred embodiments, the settle cover plate and the
support plate are, in combination, designed and configured to
enable bidirectional adjustment of the settle cover plate, with
respect to the support plate, while maintaining the support plate
connected to the base cover plate.
[0040] In a fourth family of embodiments, the invention comprehends
a method of mounting a support to bone structure. The method
comprises providing a herein-described bone support assembly,
moving the bone support assembly into position over bone structure
to be supported, sliding the base cover plate away from the base
apertures and fastening the bone fasteners, disposed in the base
apertures, to the bone structure, and sliding the base cover plate
at least partially over the bone fasteners disposed in the base
apertures and tightening the base cover plate to the support plate
thereby to prevent movement of the base cover plate and
correspondingly preventing extraction of the bone fasteners in the
base apertures.
[0041] In preferred embodiments, the method further includes
sliding the settle cover plate away from respective ones of the
bone fasteners disposed in the slot-shaped apertures and fastening
the respective bone fasteners, in the slot-shaped apertures, to the
bone structure. In such preferred embodiments, the method also
includes sliding the settle cover plate at least partially over the
respective fastened bone fasteners and tightening the settle cover
plate to the support plate thereby to prevent movement of the
settle cover plate, and correspondingly preventing extraction of
the fastened bone fasteners.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a pictorial view of a bone support plate of the
invention.
[0043] FIG. 2 is an orthogonal view of a bone support assembly of
the invention shown with base cover plate and settle cover plate
attached.
[0044] FIG. 3 shows an exploded view of the bone support assembly
of FIG. 2, with base cover plate and settle cover plate.
[0045] FIG. 4 shows a top view of the bone support assembly
illustrated in FIG. 2, and illustrates the over-lapping arrangement
of the base cover plate and settle cover plate in relationship to
respective apertures of the support plate of the assembly.
[0046] FIG. 5A and 5B show cross-sectional views of two embodiments
of the invention illustrating relationships between respective bone
fasteners and apertures of the respective support plate.
[0047] The invention is not limited in its application to the
details of construction or the arrangement of the components set
forth in the following description or illustrated in the drawings.
The invention is capable of other embodiments or of being practiced
or carried out in other various ways. Also, it is to be understood
that the terminology and phraseology employed herein is for purpose
of description and illustration and should not be regarded as
limiting. Like reference numerals are used to indicate like
components.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0048] Referring to FIG. 1, bone support assembly 10 (FIGS. 2-4) of
the invention includes a substantially flat elongate support plate
12. Support plate 12 comprises a fixed base portion 18 and a slot
portion 20. The elongate support plate 12 also includes a top
surface 14 and a bottom surface 16, the bottom surface generally
being adapted to engage the vertebrae. The length of the elongate
support plate, along one or both bottom surface 14 and top surface
16, from a most remote portion of fixed base portion 18 to a most
remote portion of slot portion 20 should be sufficient enough to
span between desired vertebrae. While support plate 12 is
illustrated in FIGS. 1-5B as being substantially flat, other
embodiments are contemplated wherein the support plate is arcuately
shaped or curved along one or both longitudinal axis 28 and
transverse axis 38 to conform the support plate to the curvature of
the vertebrae to which such support plate will be affixed.
Utilization of a curved or formed support plate can be incorporated
into any embodiment of the bone fixation assembly in accordance
with the present invention and is not limited by the specific
embodiments disclosed herein, which are provided as examples of the
possible designs which can be utilized with the present
invention.
[0049] Base apertures 22, comprising aperture walls 24, are
disposed in fixed base portion 18 of support plate 12. Similarly,
slot-shaped apertures 32, comprising aperture walls 34, are
disposed in slot portion 20 of support plate 12. Apertures 22, 32
are generally designed and configured to enable a respective shaft
of a respective bone fastener to pass through a respective aperture
to provide a fixation means of attaching support plate 12 of the
bone support assembly to respective support vertebrae. The
placement of the additional apertures in support plate 12 is
contemplated, and depends upon the application to which the bone
support assembly is to be applied.
[0050] Numerous embodiments of the invention are contemplated.
Referring to FIG. 5A, ones of apertures 22, 32 are preferably
designed and configured to demonstrate a frustoconical shape
wherein at least parts of walls 24, 34 of respective apertures 22,
32 are tapered inwardly so as to reflect a relatively smaller
cross-sectional opening at or near bottom surface 16, and
correspondingly, a relatively larger cross-sectional opening at or
near top surface 14. In such preferred embodiments, support plate
12 is mounted to the vertebrae by way of a number of bone fasteners
40, wherein at least a portion of each bone fastener is tapered to
create a cooperative engaging relationship with portions of
respective aperture walls e.g. 24, 34 of respective apertures in
which the bone fastener is inserted.
[0051] In other embodiments, such as the one illustrated in FIG.
5B, aperture walls 24, 34 comprise bearing surfaces 46 which
interface in a cooperative engaging with fasteners 40, such as e.g.
headed screws, to limit the fasteners from passing entirely and
completely through support plate 12.
[0052] Other methods of cooperative engagement between respective
bone fasteners 40 and support plate 12 whereby such cooperative
engagement secures the support plate to desired bone material, and
at the same time, limits the fasteners from passing entirely and
completely through support plate 12 will be obvious to those of
ordinary skill in art.
[0053] Referring to FIG. 1, in preferred embodiments, fixed base
portion 18 comprises a base cover plate recess 26, which is
disposed adjacent base apertures 22, and configured to accommodate
a complimentary base cover plate 62 (FIGS. 2-4). Similarly, slot
portion 20 preferably comprises a settle cover plate recess 36,
which is disposed adjacent slot-shaped apertures 32, and configured
to accommodate a complimentary settle cover plate 72 (FIGS. 2-4).
The respective complementary configurations of recesses 26, 36
bidirectionally restrict movement of respective complimentarily
configured plates 62, 72, respectively, when such plates are firmly
affixed to support plate 12 by fasteners urging plates 62, 72 into
respective recesses 26, 36 and toward bottom surface 16 of support
plate 12 as in FIGS. 2 and 4..
[0054] As previously described, the bone fasteners utilized for
securing support plate 12 to underlying bone are generally bone
screws of a type well known in the art. Preferably, the bone
fasteners utilized in the present invention are of a tapered or
modified conical type, reflecting a complementary shape to a
respective receiving aperture e.g. 22, 32 of FIG. 5A.
[0055] In some embodiments, the bone fastener comprises a screw
having a shaft wherein at least a portion of the shaft is generally
threaded, and the shaft comprises a head and a tip. The threaded
portion of the shaft is threaded to specifically engage bone. The
head of the screw is designed and configured to engage a
complimentary bearing surface, e.g. 46 of FIG. 5B, which interfaces
with the head of the screw to limit the screw from passing entirely
and completely through the support plate.
[0056] In an alternative mechanism for fixation of support plate
assembly 10 to bone material, a headless bone fastener can first be
driven into and affixed within the bone material. Support plate 12
of bone support assembly 10 is then disposed over the portion of
the bone fastener protruding from the bone material, and is fixed
to support plate 12 by threadingly engaging a nut to a
nut-receiving portion of the bone fastener with the threads of the
nut-receiving portion of the bone fastener protruding from the
bone. In such embodiments, the nut, having locking threads, is
tightened about the nut-receiving portion of the bone fastener
until such nut comes into surface-to-surface contact with a
complimentary bearing surface of the support plate, thereby
interfacing with the nut to limit the nut-receiving portion, having
the nut attached thereto, from passing entirely and completely
through the support plate.
[0057] It is well understood that bones grow along lines of stress.
Therefore, in order for fusion to occur between two or more
vertebrae, a graft disposed between the vertebrae must be subjected
to compressional forces or stressed for solid bone fusion to occur.
Bone fusion tends to be a very dynamic physiological process. Graft
material slowly resorbs as osteoclasts remove damaged bone tissue,
and osteoblasts replace damaged bone tissue with new living bone
tissue. In conventional plate constructs, wherein fasteners hold
the vertebral bodies at a fixed apart distance, any resorption of
the bone graft reduces or eliminates compressional and/or stress
forces on the graft. Accordingly, these conventional plates can
induce or cause a condition known as psuedoarthrosis manifesting
symptoms of significant pain and swelling in the vertebral area of
attachment. Therefore, it is important to maintain. the graft under
some axial loading forces or stress while allowing the plate to
compensate for the bone dynamics. This can be accomplished
utilizing the bone support assembly of the invention as described
herein.
[0058] Referring to FIGS. 1-5B, the spacing and/or orientation of
base apertures 22, slot-shaped apertures 32, and fasteners 40
within bone support assembly 10 can be designed and selected so as
to achieve a desired dynamic stress-sharing arrangement between the
bone fasteners disposed in the various combinations of base
apertures 22 and slot-shaped apertures 32 described above. That is,
the bone support assembly 10 can be tailored to a specific
application such that the stress-load carried by each respective
bone fastener can be distributed in a desired manner, including
load shifting after support plate 12 of bone support assembly 10
has been affixed to the underlying bone. Thus, bone support
assembly 10 can accommodate the dynamic environment into which it
is utilized without incurring the drawbacks of the prior art
devices described above.
[0059] Apertures 32 are slot-shaped in an oblong fashion to
accommodate settling of vertebrae as a result of e.g. axial loading
after surgical attachment to the vertebrae. The apertures can allow
for vertebral settling of about 5-6 millimeters, and preferably
about 2-3 millimeters. Sizes of apertures 32 are not contemplated
as being limited to a range of 5-6 millimeters, but are
contemplated as being designed and configured to reflect a size
great enough to enable sufficient vertebral settling as a result of
e.g. axial loading.
[0060] In all of the embodiments shown in FIGS. 1-5B, elongate
slot-shaped apertures 32 are capable of receiving at least one bone
fastener therein. The bone fasteners can be affixed within
slot-shaped apertures 32 in a manner similar to that discussed
above. Elongate slot-shaped apertures 32 enable a substantial
margin for adjustment and proper location of the bone fastener with
relationship to the support plate and, as discussed above, the bone
fasteners can be made to slide freely with relationship to aperture
walls 34 of slot-shaped apertures 32.
[0061] Support plate 12 can comprise a bone engagement surface
disposed on bottom surface 16 of support plate 12 for enhancing the
engagement of support plate 12 to the vertebrae. Preferably, the
bone engagement surface includes a texturized surface disposed on
substantially all of bottom surface 16 of the support plate 12. In
other embodiments, the texturized surface can be disposed on only a
portion of bottom surface 16. The texturized surface of bottom
surface 16 of support plate 12 can include etched, roughened,
grooved, knurled, or other substantially functional contouring
equivalent as is known to those skilled in the art.
[0062] In some embodiments, a bone fastener cover assembly 50
comprises at least one cover plate, wherein the bone fastener cover
assembly is designed and configured to overlap at least portions of
ones of the apertures thus preventing a "backing out" of bone
fasteners from the bone to which the bone fasteners are implanted.
In the embodiments illustrated in FIGS. 2-4, bone fastener cover
assembly 50 is illustrated in two portions comprising a base
portion cover assembly 60 and a slot-portion cover assembly 70.
Cover assemblies 60, 70 preferably are designed and configured to
engage in a complementary relationship with respective recesses 26,
36, respectively, disposed on support plate 12. The illustrated
embodiments reflect base cover plate recess 26, and settle cover
plate recess 36, being adapted to receive complimentary base cover
plate 62 and settle cover plate 72, respectively. The location and
configuration of the recesses can be varied according to a desired
or specific cover plate(s) to be utilized for the purpose of
preventing backing out of the fasteners in a variety of different
sized apertures.
[0063] Referring to the embodiments illustrated in FIGS. 2-4, bone
support assembly 10 comprises base portion cover assembly 60
comprising base cover plate 62 having an upper surface 64 and a
lower surface 65, at least one base cover plate fastener 66, and at
least one base cover plate aperture 68, ones of the base cover
plate apertures 68 having aperture walls 69. Similarly, bone
support assembly 10 also comprises slot portion cover assembly 70
comprising settle cover plate 72 having a superior surface 74 and
an inferior surface 75, at least one settle cover plate fastener
76, and at least one settle cover plate aperture 78, ones of the
settle cover plate apertures 78 having aperture walls 79.
[0064] Base cover plate 62 of base portion cover assembly 60 is
affixed to support plate 12 via inserting base cover plate fastener
66 through base cover plate aperture 68 and engaging base cover
plate fastener 66 with a first base plate fastener aperture 42
disposed in support plate 12, wherein first base plate fastener
aperture 42 reflects an engagement relationship with base cover
plate fastener 66. Similarly, settle cover plate 72 of slot portion
cover assembly 70 is affixed to support plate 12 via inserting
settle cover plate fastener 76 through settle cover plate aperture
78 and engaging settle cover plate fastener 76 with a second settle
plate fastener aperture 44 disposed in support plate 12, wherein
second settle plate fastener aperture 44 reflects an engagement
relationship with settle cover plate fastener 76.
[0065] In preferred methods of affixing bone support assembly 10 to
bone material, the method comprises bidirectionally adjusting one
or both settle cover plate 72 and base cover plate 62 about settle
cover plate fastener 76 and base cover plate fastener 66,
respectively, to enable a surgeon, or other inserter, during the
surgical procedure, to insert the bone fasteners into respective
apertures, thus providing a support backing for the bone support
assembly while maintaining a connection of backing plates 62, 72,
thus reducing the potential number of loose components of the bone
support assembly.
[0066] Referring to FIG. 3, the size of base cover plate aperture
68 is preferably greater than the size of the shaft of
corresponding base cover plate fastener 66 by a first dimension
greater than or substantially equal to that amount of bidirectional
movement of base cover plate 62 about base cover plate fastener 66,
relative to support plate 12 necessary to gain fastening access to
at least one bone fastener while prohibiting fastening access to at
least another bone fastener, wherein each of the first bone
fasteners is disposed in a separate and distinct base aperture 22,
and whereby at no time are all bone fasteners accessible for
fastening to the bone structure.
[0067] Still referring to FIG. 3, base apertures 22 are preferably
not designed to provide for longitudinal movement of bone fasteners
40 in apertures 22. Thus, the size of the respective portions of
apertures 22 which are substantially aligned with the top surface
of base cover plate recess 26 preferably is substantially equal to
the size of the portion of the bone fastener most remote from the
supported bone. The amount of overlap of base cover plate 62 over
bone fasteners in each of apertures 22, when base cover plate 62 is
firmly affixed in a tightened position to support plate 12, as in
FIGS. 2 and 4, directly affects the required difference in
respective cross-sectional sizes between the shaft of base cover
plate fastener 66 and the narrowest portion of base cover plate
aperture 68. So if base cover plate 62, in such plate's tightened
position, as in FIGS. 2 and 4, overlaps bone fasteners in each of
apertures 22 by e.g. approximately 0.5 mm, the respective
cross-sectional size of the narrowest portion of base cover plate
aperture 68 must be at least e.g. about 1.0 mm greater than the
cross-sectional size of the shaft of base cover plate fastener 66,
thus allowing for one or both longitudinal and transverse movement
of at least e.g. about 0.5 mm of plate 66 about the shaft of
fastener 66 when such fastener is not fully engaged into aperture
68, thereby enabling bidirectional adjustment of plate 62.
[0068] Regardless of the chosen embodiment, the cross-sectional
size of the narrowest portion of base cover plate aperture 68 is
preferably equal to or greater than the sum of the cross-sectional
size of the shaft of base cover plate fastener 62 plus two times
the amount of overlap of base cover plate 62 over bone fasteners in
each of apertures 22. Thus, if base cover plate 62 overlaps bone
fasteners in each of apertures 22 by 0.75 mm, and the
cross-sectional size of the shaft of base cover plate fastener 66
is 2.0 mm, the cross-sectional size of the narrowest portion of
base cover plate aperture 68 is no less than 3.5 mm.
[0069] Again referring to FIG. 3, while the shaft of base cover
plate fastener 66 has a smaller cross-sectional size than that of
base cover plate aperture 68, the shape and shape and
cross-sectional area of fastener 66 is complimentary to the shape
and cross-sectional area of base plate fastener aperture 42, thus
enabling cooperative fastening engagement between fastener 66 and
the walls of base plate fastener aperture 42. Thus, when base cover
plate fastener 66 is generally inserted through base cover plate
aperture 68 and only partially engaged into base plate fastener
aperture, base cover plate 62 can be bidirectionally adjusted to
access bone fasteners 40 disposed in either of apertures 22 while
still maintaining connection to support plate 12.
[0070] The head of base cover plate fastener 66 and a portion of
wall 69 of base cover plate aperture 68 have complimentary tapered
configurations wherein the cross-sectional opening of aperture 68
adjacent the upper surface of plate 62 is greater than the
cross-sectional opening of aperture 68 adjacent the lower surface
of plate 62. Such a complimentary tapered configuration enables a
installer to fully impede bidirectional movement of base cover
plate 62 about base cover plate fastener 66 by tightening fastener
66 into a fully engaged relationship with bone plate fastener
aperture 42.
[0071] Similarly, the size of settle cover plate aperture 78 is
preferably greater than the size of the shaft of settle cover plate
fastener 76 by a first measure greater than or substantially equal
to that amount of bidirectional movement of settle cover plate 72
about settle cover plate fastener 76, relative to support plate 12
necessary to gain fastening access to at least one bone fastener
while prohibiting fastening access to at least another bone
fastener, wherein each of the first bone fasteners is disposed in a
separate and distinct slot-shaped aperture 32, and whereby at no
time are all bone fasteners accessible for fastening to the bone
structure.
[0072] Still referring to FIG. 3, slot-shaped apertures 32 are
preferably designed to provide for longitudinal movement of bone
fasteners 40 in apertures 32, thus allowing settling of supported
vertebrae. Therefore, the largest transverse distance of the
respective portions of apertures 32, which are substantially
aligned with the top surface of settle cover plate recess 36, is
substantially equal to the size of the portion of the bone fastener
most remote from the supported bone. The amount of overlap of
settle cover plate 72 over bone fasteners in each of apertures 32,
when settle cover plate 72 is firmly affixed in a tightened
position to support plate 12, as in FIGS. 2 and 4, directly affects
the required difference in cross-sectional sizes between the shaft
of settle cover plate fastener 76 and the narrowest portion of
settle cover plate aperture 78. So if settle cover plate 72, in
such plate's tightened position, overlaps bone fasteners in each of
apertures 32 by e.g. approximately 0.6 mm, the cross-sectional size
of the narrowest portion of settle cover plate aperture 78 must be
at least e.g. about 1.2 mm greater than the cross-sectional
diameter of the shaft of settle cover plate fastener 76, thus
allowing for one or both longitudinal and transverse movement of at
least e.g. about 0.6 mm of plate 76 about the shaft of fastener 76
when such fastener is not fully engaged into aperture 78, thereby
enabling bidirectional adjustment of plate 72.
[0073] Generally, the cross-sectional size of the narrowest portion
of settle cover plate aperture 78 is preferably equal to or greater
than the sum of the cross-sectional size of the shaft of settle
cover plate fastener 72 and two times the amount of overlap of
settle cover plate 72 over bone fasteners in each of apertures 32.
Thus, if settle cover plate 72 overlaps bone fasteners in each of
apertures 32 by 0.8 mm, and the cross-sectional size of the shaft
of settle cover plate fastener 76 is 2.2 mm, the cross-sectional
size of the narrowest portion of settle cover plate aperture 78 is
no less than 3.8 mm.
[0074] Still referring to FIG. 3, while the shaft of settle cover
plate fastener 76 has a smaller cross-sectional size than that of
settle cover plate aperture 78, the shape and cross-sectional area
of fastener 76 is complimentary to the shape and cross-sectional
area of settle plate fastener aperture 44 thus enabling cooperative
fastening engagement between fastener 76 and the walls of settle
plate fastener aperture 44. Thus, when settle cover plate fastener
76 is generally inserted through settle cover plate aperture 78 and
only partially engaged into settle plate fastener aperture, settle
cover plate 72 can be bidirectionally adjusted to access bone
fasteners 40 disposed in either of apertures 32 while still
maintaining connection to support plate 12.
[0075] As with the base cover plate fastener, the head of settle
cover plate fastener 76 and a portion of wall 79 of settle cover
plate aperture 78 have complimentary tapered configurations wherein
the cross-sectional opening of aperture 78 adjacent the upper
surface of plate 72 is greater than the cross-sectional opening of
aperture 78 adjacent the lower surface of plate 72. Such a
complimentary tapered configuration enables a installer to fully
impede bidirectional movement of settle cover plate 72 about settle
cover plate fastener 76 by tightening fastener 76 into a fully
engaged relationship with bone plate fastener aperture 44.
[0076] The above-described embodiments generally reflect
laterally-symmetric embodiments of support plate 12 having pairs of
either circular or elongate, slot-shaped apertures, wherein a first
aperture of each pair is located on a first side of longitudinal
axis 28, and a second aperture of each pair is located on a second
side of longitudinal axis 28, as in FIG. 1. While
laterally-symmetric embodiments are preferred, other embodiments of
the invention are contemplated, such as embodiments wherein
respective apertures, e.g. 22, 32, have cross-sectional shapes
other than circular or elongate. In other embodiments, apertures,
e.g. 22, 32, are not aligned, but are arranged in a staggered
configuration. In yet other embodiments, a cover plate may cover a
first respective bone fastener in an aperture more or less than
such cover plate covers a second respective bone fastener, such
that the respective cover plate aperture, e.g. 68, 78, is not
substantially circular, but e.g. elongate and/or slot-shaped, to
accommodate sufficient bidirectional movement to access respective
bone fasteners in respective apertures. Other embodiments of the
invention will be obvious to those of ordinary skill in the
art.
[0077] Bone support assembly 10 is preferably affixed to the
anterior portion of desired vertebrae of the recipient such that
fixed base portion 18 is disposed and attached to the most caudal
of the desired vertebrae. Accordingly, slot portion 20 is
preferably disposed and attached to the more cephalic of the
desired vertebrae, wherein the most caudal of the desired vertebrae
assists in providing a foundation or base contributing to
supporting ones of the more cephalic vertebrae.
[0078] Bone support assembly 10 can be constructed of any suitable
material. Preferably, bone support assembly 10 and other
components, such as the fasteners, are constructed of suitable
materials which are compatible with the uses and environments into
which bone support assembly 10 will be utilized. Preferably, bone
support assembly 10 is constructed of metallic materials such as
titanium, stainless steel, or other metal alloys. The material
which bone support assembly 10 is constructed of should have
strength and be non-reactive and non-antigenic to biological
systems.
[0079] Those skilled in the art will now see that certain
modifications can be made to the apparatus and methods herein
disclosed with respect to the illustrated embodiments, without
departing from the spirit of the instant invention. And while the
invention has been described above with respect to the preferred
embodiments, it will be understood that the invention is adapted to
numerous rearrangements, modifications, and alterations, and all
such arrangements, modifications, and alterations are intended to
be within the scope of the appended claims.
[0080] To the extent the following claims use means plus function
language, it is not meant to include there, or in the instant
specification, anything not structurally equivalent to what is
shown in the embodiments disclosed in the specification.
* * * * *