U.S. patent application number 11/428693 was filed with the patent office on 2006-12-28 for bone compression device.
This patent application is currently assigned to BAYLOR COLLEGE OF MEDICINE. Invention is credited to Michael H. Heggeness.
Application Number | 20060293671 11/428693 |
Document ID | / |
Family ID | 23352931 |
Filed Date | 2006-12-28 |
United States Patent
Application |
20060293671 |
Kind Code |
A1 |
Heggeness; Michael H. |
December 28, 2006 |
BONE COMPRESSION DEVICE
Abstract
The invention relates to bone compression devices and bone
compression systems, and in particular, to bone compression devices
and systems for use in connection with vertebrae. The bone
compression devices and bone compression systems are disposed, or
installed, along at least one bone to maintain the at least one
bone in a desired spatial relationship. Broadly, the invention is
directed to a bone compression device for placing in communication
with at least one bone having a bone radius of curvature, the bone
compression device comprising a plate having a pre-formed shape, a
deformed shape, and at least one elastic shape therebetween, the
pre-formed shape having a pre-formed radius of curvature less than
the bone radius of curvature, the deformed shape having a deformed
radius of curvature greater than the bone radius of curvature, and
at least one of the at least one elastic shapes having an elastic
radius of curvature that substantially corresponds to the bone
radius of curvature. The invention is also directed to a bone
compression system wherein the plate includes a string attached to
each end of the plate and a tensioner for facilitating the movement
of the plate from the pre-formed shape to the at least one elastic
shape. Methods of maintaining a bone in a spatial relationship and
methods of contouring the bone compression devices are also
disclosed.
Inventors: |
Heggeness; Michael H.;
(Bellaire, TX) |
Correspondence
Address: |
CONLEY ROSE, P.C.
P. O. BOX 3267
HOUSTON
TX
77253-3267
US
|
Assignee: |
BAYLOR COLLEGE OF MEDICINE
One Baylor Plaza
Houston
TX
|
Family ID: |
23352931 |
Appl. No.: |
11/428693 |
Filed: |
July 5, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10273853 |
Oct 17, 2002 |
7115129 |
|
|
11428693 |
Jul 5, 2006 |
|
|
|
60344980 |
Oct 19, 2001 |
|
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Current U.S.
Class: |
606/279 |
Current CPC
Class: |
A61B 17/8869 20130101;
A61B 17/8004 20130101; A61B 17/808 20130101; A61B 17/7059
20130101 |
Class at
Publication: |
606/069 |
International
Class: |
A61F 2/30 20060101
A61F002/30 |
Claims
1. A device to maintain at least two vertebrae in a spatial
relationship with each other, the at least two vertebrae forming a
bone radius of curvature, the device comprising: a plate having a
pre-formed shape, a deformed shape, and at least one elastic shape
between the preformed shape and the deformed shape; wherein the
pre-formed shape has a pre-formed radius of curvature less than the
bone radius of curvature; wherein the deformed shape has a deformed
radius of curvature greater than the bone radius of curvature;
wherein at least one of the elastic shapes has an elastic radius of
curvature that substantially corresponds to the bone radius of
curvature; wherein said plate has an axis of elastic curvature;
means for fastening said plate to the spine, said fastening means
defining a direction of fastening; and wherein the direction of
fastening is substantially orthogonal to said axis of elastic
curvature.
2. The device of claim 1, wherein the plate includes at least one
fastener hole adapted to receive a fastener.
3. The device of claim 1, wherein the plate includes a first end
and a second end.
4. The device of claim 3, wherein the plate includes at least one
fastener hole adapted to receive a fastener at the first end and at
least one fastener hole adapted to receive a fastener at the second
end.
5. The device of claim 2, wherein said at least one fastener is
selected from a group consisting of bone screws and bolts.
6. The device of claim 4, wherein the at least one fastener at the
first end is selected from a group consisting of bone screws and
bolts and wherein the at least one fastener at the second end is
selected from a group consisting of bone screws and bolts.
7. The device of claim 1, wherein the plate includes a length
having a longitudinal axis and a width having a lateral axis, the
preformed radius of curvature being disposed along the length.
8. The device of claim 1, wherein the plate includes a length
having a longitudinal axis and a width having a lateral axis, the
pre-formed radius of curvature being disposed along the width.
9. The device of claim 1, wherein the plate includes a first end, a
second end, at least two fastener holes disposed near the first
end, and at least two fastener holes disposed near the second
end.
10. The device of claim 1, wherein the plate includes a first end,
a second end, and at least two attachment members.
11. The device of claim 10, wherein at least one of the at least
two attachment members is a hole.
12. The device of claim 10, wherein at least one of the at least
two attachment members is a loop.
Description
RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 60/344,980, filed Oct. 19, 2001.
BACKGROUND OF TILE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to surgical devices, and in
particular, to bone compression devices for maintaining bones,
namely, one or more vertebrae, in a desired spatial relationship.
The invention also relates to methods for maintaining at least one
bone in a spatial relationship and methods for contouring the bone
compression devices for use in maintaining bones in a desired
spatial relationship.
[0004] 2. Description of Related Art
[0005] The use of bone compression devices in connection with
vertebrae are known in the art. Many of these prior bone
compression devices are directed to fusing together two or more
vertebrae. However, the success rate of fusing together four or
more levels is extremely low, i.e., approximately 50% as compared
to approximately 95% for two level fusion and 98%-99% for single
level fusion. At least one reason contemplated for the increase in
the percentage of failures of the bone compression devices is that
the bone compression devices do not substantially correspond to the
anatomical curvature of the bone to which they are applied.
Accordingly, prior to installation, or implantation by the surgeons
the bone compression devices must be manipulated or shaped to
substantially correspond to the shape of the bone or bones. As the
length of the bone compression device increases, e.g., to furs
three or more vertebrae, the amount of manipulation, e.g., bending,
required generally increases. As a result of his manipulation, the
bone compression device may become permanently deformed, and thus
weakened, or experience hysteresis.
[0006] As with most all materials used to form surgical implants
and devices, e.g., titanium and stainless steel and various alloys,
the devices include a pre-formed shape, i.e., the shape of the
device as formed during manufacture, and a deformed shape, i.e.,
the shape of the device after sufficient force is exerted on the
device to permanently change the shape of the device. In between
the pre-formed shape and the deformed shape are numerous elastic
shapes. These elastic shapes have a tendency to revert back toward
the pie-formed shape over a period time ranging from near
immediately, e.g., a few seconds, to a number of weeks or even
months. In fact, most materials experience a certain amount of
reversion of shape immediately and then, over an extended period of
time, experience additional amounts of reversion of shape. This
reversion of shape is referred to as hysteresis. One example of
hysteresis is illustrated in materials having what has been
referred to as "metal memory." Because of hysteresis, many prior
bone compression devices do not remain properly shaped and
ultimately fail.
[0007] Both the weakening of the bone compression device and
hysteresis is further complicated by the use of fasteners, e.g.,
bone screws or bolts, to secure the bone compression devise to the
bone. If the fastener holes are misshapen during the manipulation
by the surgeon, the fasteners, when installed, generally force the
bone compression device back to its original shape, i.e. away from
manipulated shape formed by the surgeon to correspond to the shape
of the bone.
[0008] For example, in one prior approach, the bone compression
device is generally straight. Because the spine is lordotic, the
bone compression device must be manipulated, or bent, by the
surgeon to attempt to shape the bone compression device to
correspond to the curvature of the spine. These devices, after
implantation, experience hysteresis resulting in the bone
compression device attempting to revert backs to its pre-formed
shape, i.e., straight. As a result, the bone compression device
experiences a higher incidence of failure over long lengths. Such
hysteresis is increased by the installation of the fasteners into
misshapen fastener holes to secure the bone compression device to
the bone. As bone screws or other fasteners are inserted to secure
the bone compression device to the bone, pressure is placed on the
plate to push it onto the bone resulting in the plate straightening
out, i.e., being manipulated away from the shape desired by the
surgeon.
[0009] In another prior approach, the bone compression device is
slightly contoured to approximate the curvature of the bone to
which the bone compression device is to be connected. However, the
pre-formed curvature of the bone compression device rarely, if
ever, accurately corresponds to the curvature of the bone to which
it is to be implanted. Therefore, the surgeon must still manipulate
these bone compression devices to provide additional lordosis or
curvature to correspond to the curvature of the bone. While the
amount of manipulation by the surgeon may be lessened, these bone
compression devices also experience hysteresis resulting in
potential failure of the bone compression device.
[0010] Accordingly, prior to the development of the present
invention, there has been no bone compression device or bone
compression system for placing in communication with at least one
bone having a bone radius of curvature, methods of maintaining at
least two vertebrae in a spatial relationship with each other, or
methods of contouring bone compression devices, which: decrease the
rate of failure of the bone compression devices due to hysteresis;
utilize hysteresis to increase the rate of success of the bone
compression devices; decrease the rate of failure of the bone
compression devices when employed on long bones or multiple bones,
e.g., three or more vertebrae; and provide compressive forces to
the bone to which the bone compression devices are implanted
thereby increasing the grip of the bone compression device on the
bone. Therefore, the art has sought bone compression devices and
bone compression systems for placing in communication with at least
one bone having a bone radius of curvature, methods of maintaining
at least two vertebrae in a spatial relationship with each other,
and methods of contouring bone compression devices, which: decrease
the rate of failure of the bone compression devices due to
hysteresis; utilize hysteresis to increase the rate of success of
the bone compression devices; decrease the rate of failure of the
bone compression devices when employed on long bones or multiple
bones, e.g., three or more vertebrae; and provide compressive
forces to the bone to which the bone compression devices are
implanted, thereby increasing the grip of the bone compression
device on the bone. It is believed that the present invention will
achieve these objectives and overcome the disadvantages of other
compression devices and bone compression systems for placing in
communication with at least one bone having a bone radius of
curvature, methods of maintaining at least two vertebrae in a
spatial relationship with each other, and methods of contouring
bone compression devices in the field of the invention, but its
results or effects are still dependent upon the skill and training
of the operators and surgeons.
SUMMARY OF INVENTION
[0011] In accordance with the invention, the foregoing advantages
have been achieved through the present bone compression device for
placing in communication with at least one bone having a bone
radius of curvature, the bone compression device comprising a plate
having a pre-formed shape, the pre-formed shape having a pre-formed
radius of curvature less than the bone radius of curvature.
[0012] A further feature of the bone compression device is that the
plate may include a deformed shape and at least one elastic shape
between the pre-formed shape and the deformed shape, the deformed
shape hating a deformed radius of curvature greater than the bone
radius of curvature, and at least one of the at least one elastic
shapes having an elastic radius of curvature that substantially
corresponds to the bone radius of curvature. Another feature of the
bone compression device is that the plate may include a first end,
a second end, and at least two attachment members. An additional
feature of the bone compression device is that at least one of the
at least two attachment members may be a hole, Still another
feature of the bone compression device is that at least one of the
at least two attachment members may be a loop. A further feature of
the bone compression device is that at least one of the two
attachment members may be disposed at the first end of the plate
and another of the at least two attachment members may be disposed
at the second end of the plate. Another feature of the bone
compression device is that at least one of the at least two
attachment members is may be hole. An additional feature of the
bone compression device is that at least one of the at least two
attachment members may be a loop. Still another feature of the bone
compression device is that the plate may include a first end, a
second end, and at least two attachment members. A further feature
of the bone compression device is that the plate may include a
length having a longitudinal axis and a width having a lateral
axis, the preformed radius of curvature being disposed along the
length. Another feature of the bone compression device is that the
plate may include a length having a longitudinal axis and a width
having a lateral axis, the pre-formed radius of curvature being
disposed along the width. An additional feature of the bone
compression device is that the plate may include a first end, a
second end, at least two fastener holes disposed near the first
end, and at least two fastener holes disposed near the second
end.
[0013] In accordance with the invention, the foregoing advantages
have also been achieved through the present bone compression system
for placing in communication with at least one bone having a bone
radius of curvature, the bone compression system comprising: a
plate having a first end, a second end, a first attachment member,
a second attachment member, a preformed shape, a deformed shape,
and at least one elastic shape between the pre-formed shape and the
deformed shape, the pre-formed shape having a pie-formed radius of
curvature less than the bone radius of curvature, the deformed
shape having a deformed radius of curvature greater than the bone
radius of curvature, and at least one of the at least one elastic
shapes having an elastic radius of curvature that substantially
corresponds to the bone radius of curvature; a string having a
first end and a second end, wherein the first end of the string is
releasably secured to the first attachment member and the second
end of the string is releasably secured to the second attachment
member; and a tensioner having a shaft and a spool, the tensioner
facilitating the movement of the plate from the pre-formed shape to
the at least one elastic shape that substantially corresponds to
the bone radius of curvature.
[0014] A further feature of the bone compression system is that the
first and second attachment members may be holes, one hole being
disposed at the first end of the plate and the second hole being
disposed at the second end of the plate. Another feature of the
bone compression system is that the first end and the second end of
the string each may include at least one hook. An additional
feature of the bone compression system is that the first and second
attachment members may be loops, one loop being disposed at the
first end of the plate and the second loop being disposed at the
second end of the plate. Still another feature of the bone
compression system is that the first end and the second end of the
string each may include at least one book, A flyer feature of the
bone compression system is that the tensioner may include at least
one plate hole interface member. Another feature of the bone
compression system is that the tensioner may include a rachet. An
additional feature of the bone compression system is that the first
attachment member may be disposed at the first end of the plate and
the second attachment member may be disposed at the second end of
the plate. Still another feature of the bone compression system is
that the plate may include a length having a longitudinal axis and
a width having a lateral axis, the pre-formed radius of curvature
and the at least one elastic radius of curvature being disposed
along the length. A further feature of the bone compression system
is that the plate may include a length having a longitudinal axis
and a width having a lateral axis, the pie-formed radius of
curvature and the at least one elastic radius of curvature being
disposed along the width. Another feature of the bone compression
system is that the plate may include a first end, a second end, at
least two fastener holes disposed near the first end, and at least
two fastener holes disposed near the second end.
[0015] In accordance with the invention, the foregoing advantages
have also been achieved through the present method of contouring a
bone compression device for placing in communication with at least
one bone having a bone radius of curvature, the method comprising
the steps of: providing a bone compression device having, a plate,
the plate including a first end, a second end, a first attachment
member, a second attachment member, a pre-formed shape, a deformed
shape, and at least one elastic shape between the pre-formed shape
and the deformed shape, the pre-formed shape having a pre-formed
radius of curvature less than the bone radius of curvature, the
deformed shape having a deformed radius of curvature greater than
the bone radius of curvature, and at least one of the at least one
elastic shapes having an elastic radius of curvature that
substantially corresponds to the bone radius of curvature;
releasably securing a string having a first end and a second end to
the first attachment member and the second attachment member of the
plate; applying a tensioner having a shaft and a spool to the
string; and actuating the tensioner whereby the string is wrapped
around the spool and the plate is moved from the pre-formed shape
to at least one of the at least one elastic shapes.
[0016] A further feature of the method of contouring a bone
compression device for placing in communication with at least one
bone having a bone radius of curvature is that the string may be
releasably secured to the first and second attachment members by
passing first end of the string through the first attachment member
and tying first end of the string into a knot, and passing second
end of the string through the second attachment member and tying
second end of the string into a knot. Another feature of the method
of contouring a bone compression device for placing in
communication with at least one bone having a bone radius of
curvature is that the first and second ends of the string may
include first and second hooks, the string being releasably secured
to the first and second attachment members by passing the first
hook through the first attachment member and passing the second
book through the second attachment member.
[0017] In accordance with the invention, the foregoing advantages
have also been achieved through the present method of maintaining
at least two vertebrae in a spatial relationship with each other,
the at least two vertebrae forming a bone radius of curvature, the
method comprising the steps of: providing a bone compression device
having a plate, the plate including a first end, a second end, a
pre-formed shape, a deformed shape, and at least one elastic shape
between the pre-formed shape and the deformed shape, the pre-formed
shape having a pre-formed radius of curvature less than the bone
radius of curvature, the deformed shape having a deformed radius of
curvature greater than the bone radius of curvature, and at least
one of the at least one elastic shapes having an elastic radius of
curvature that substantially corresponds to the bone radius of
curvature; contouring the bone compression device by moving the
bone compression device from the pre-formed shape to at least one
of the at least one elastic shapes corresponding to the bone radius
of curvature; disposing the bone compression device along the bone
radius of curvature; and securing the bone compression device to
the at least two vertebrae.
[0018] A further feature of the method of maintaining at least two
vertebrae in a spatial relationship with each other is that at
least one bone graft may be disposed between the at least two
vertebrae prior to securing the bone compression device to the at
least two vertebrae. Another feature of the method of maintaining
at least two vertebrae in a spatial relationship with each other is
that the bone compression device may be contoured to the bone
radius of curvature formed by at least three vertebrae. An
additional feature of the method of maintaining at least two
vertebrae in a spatial relationship with each other is that the
bone compression device may be contoured to the bone radius of
curvature formed by at least four vertebrae. Still another feature
of the method of maintaining at least two vertebrae in a spatial
relationship with each other is that the bone compression device ay
be contoured to the bone radius of curvature formed by at least
five vertebrae. A further feature of the method of maintaining at
least two vertebrae in a spatial relationship with each other is
that the bone compression device may include a first fastener hole
and a second fastener hole disposed near the first end and a third
fastener hole and a fourth fastener hole disposed near the second
end, the third fastener hole being disposed diagonally with respect
to the second fastener hole and the fourth fastener hole being
disposed diagonally with respect to the first fastener hole, and
wherein the first end is secured to one of the at least two
vertebrae with a first fastener inserted through the first fastener
hole, the second end is secured to one of the at least two
vertebrae with a second fastener inserted through the fourth
fastener hole, the first end is further secured to one of the at
least two vertebrae with a third fastener inserted through the
second fastener hole, and the second end is further secured to one
of the at least two vertebrae with a fourth fastener inserted
through the third fastener hole.
[0019] The bone compression devices and bone compression systems
for placing in communication with at least one bone having a bone
radius of curvature, methods of maintaining at least two vertebrae
in a spatial relationship with each other; and methods of
contouring bone compression devices have the advantages oft
decreasing the rate of failure of the bone compression devices due
to hysteresis; utilize hysteresis to increasing the rate of success
of the bone compression devices; decreasing the rate of failure of
the bone compression devices when employed on long bones or
multiple bones, e.g., three or more vertebrae; and providing
compressive forces to the bone to which the bone compression
devices are implanted thereby increasing the grip of the bone
compression device on the bone. As mentioned above, it is believed
that the present invention still achieve these objectives and
overcome the disadvantages of other surgical devices and surgical
systems and methods in the field of the invention, but its results
or effects are still dependent upon the skill and training of the
operators and surgeons.
BRIEF DESCRIPTION OF DRAWINGS
[0020] FIG. 1a is a longitudinal side view of a human spinal
column.
[0021] FIG. 1b is a detailed side view of two human vertebrae
hawing a disk disposed between the two vertebrae.
[0022] FIG. 1c is a detailed side view of two human vertebrae with
a bone graft disposed between two vertebrae.
[0023] FIG. 2 is a schematic showing the radius of curvature of a
longitudinal curve.
[0024] FIG. 3a is a longitudinal side view of a prior art bone
compression device before being formed into its implantation
shape.
[0025] FIG. 3b is a longitudinal side view of the prior art bone
compression device shown in FIG. 3a in its implantation shape
[0026] FIG. 4 is a longitudinal side view a of a specific
embodiment of the bone compression device of the present
invention.
[0027] FIG. 5 is a top view of the bone compression device shown in
FIG, 4.
[0028] FIG. 6 is a longitudinal side view of another specific
embodiment of the bone compression device of the present
invention.
[0029] FIG. 7 is a top view of the bone compression device shown in
FIG. 6,
[0030] FIG. 8 is a side view of a specific embodiment of the
tensioner of one specific embodiment of the bone compression system
of the present invention.
[0031] FIG. 9 is a side view of a specific embodiment of the string
of one specific embodiment of the bone compression system of the
present invention.
[0032] FIG. 10 is side view of one specific embodiment of the bone
compression system of the present invention.
[0033] While the invention will be described in connection with the
preferred embodiment, it will be understood that it is not intended
to limit the invention to that embodiment. On the contrary, it is
intended to cover all alternatives, modifications, and equivalents,
as may be included within the spirit and scope of the invention as
defined by the appended claims,
DETAILED DESCRIPTION AND SPECIFIC EMBODIMENTS
[0034] The present invention is directed to bone compression
devices and bone compression systems for maintaining at least one
bone in a desired spatial relationship. While the description of
the bone compression devices, bone compression systems, and methods
of contouring the bone compression devices will be directed to use
in connection with two or more vertebrae, it is to be understood
that the bone compression devices, bone compression systems,
methods of maintaining at least two vertebrae in a spatial
relationship with each other, and methods of contouring the bone
compression devices of the invention may be used, or performed, in
connection with any bone in which it is desired to maintain, or
place, at least one bone in a desired spatial relationship, e.g.,
the pelvis, the femur, the fibula, the tibia, humerus, ulna,
radius, or any other bone. For example, the bone compression
devices of the invention may be employed in long bone, e.g., femur,
and pelvic fracture fixation. Further, the bone compression device
may be used in connection with rigid locked screw-plates and
screw-plates that permit some screw subsidence or angulation, both
of which are bone compression devices know in the art.
[0035] In the preferred embodiments, the bone compression devices
are utilized to maintain one or more vertebrae, and more
preferably, three or more vertebrae, of the spine, and in
particular, the cervical vertebrae of humans, in a desired spatial
relationship. In these embodiments, prior to the installation of
the bone compression device, one or more bone grafts are generally
disposed between two or more vertebrae. As illustrated in FIGS. 1b
and 1c, for example, after a disk 26, located between two vertebrae
21, is removed from spine 20, a bone graft 28, e.g., a portion of
the patients' own bone, an allograft portion of bone donated from
another individual), or synthetic bone grafts or cages or boxes
such as those made from carbon fiber, metal particularly titanium),
or ceramics, is usually disposed in the space created by the
removal of the disk 26. Thereafter, the bone compression devices of
the invention are installed and secured to at least the vertebra 21
disposed above the graft and the vertebra 21 disposed below the
graft. Accordingly, bone graft 28 is compressed between the two
vertebrae 21 to maintain bone graft 28 in a spatial relationship
with vertebrae 21.
[0036] It is contemplated that the bone compression devices of the
invention are suitable for fusing, e.g., being secured to, more
than three vertebrae having one or more grafts disposed between two
or more of the vertebrae. Therefore, in these embodiments, the
vertebrae in proximity to the removed disk(s) are maintained in a
desired spatial relationship to one another. Therefore, the
vertebrae are permitted to heal, and, in some cases, the synthetic
bone graft is permitted to be incorporated into the vertebrae using
bone growth factors and other biologically active substances to
facilitate the growth of bone over the synthetic bone graft.
[0037] Referring now to FIG. 1a, spine 20 includes vertebrae 21 and
has posterior side 23 and anterior side 24. Spine 20 includes
numerous bone radius of curvatures 22 along the longitudinal length
of spine 20. As shown in FIG. 1, bone radius of curvatures 22 are
identified along anterior side 24 of spine 20. Although the bone
compression devices of the invention may be installed, or
implanted, along the posterior side 23 of spine 20, generally, bone
compression devices are implanted along anterior side 24 of spine
20.
[0038] Radius of curvature, as used herein referring to the shape
of the bone(s) as well as the shape of the bone compression devices
and systems, is measured by determining the radius of a circle
formed by the longitudinal curve of the bone (bone radius of
curvature) or bone compression device (pre-formed radius of
curvature, deformed radius of curvature, and elastic radius of
curvature) placed along the circumference of the circle formed by
the longitudinal curve of the bone or bone compression device.
Accordingly, the larger the circle formed by the longitudinal curve
of the bone or bone compression device, the larger the
corresponding curvature, i.e., the greater the radius of curvature.
Therefore, as the longitudinal curve approaches a straight line,
the radius of curvature approaches infinity. FIG. 2 illustrates how
radius of curvature R is determined along curvature L with respect
to circle A having center C.
[0039] As illustrated in FIGS. 3a and 3b, one prior bone
compression device 10 includes plate 11 having longitudinal length
13. As shown in FIG. 3a, plate is generally straight. As such, it
must be manipulated, e.g., bent, to correspond to the shape of the
bone to which it will be implanted. In other words, bone
compression device 10 must be manipulated to correspond to the bone
radius of curvature. As shown in FIG. 3b, plate 10 is bent in the
direction of arrows 12 and 14 to create the desired radius of
curvature. However, due to hysteresis, after plate 11 is bent in
this manner plate 11 begins to revert back to its original shape
(FIG. 3a) by moving in the direction of arrows 16 and 18.
Alternatively, plate 11 is bent to its deformed shape, thereby
weakening plate 11.
[0040] Referring now to FIGS. 4-7, in one aspect the present
invention is directed to bone compression device 40 having plate
50, first end 51, second end 52, upper surface 53, lower surface
54, longitudinal axis 55 along length L of plate 50, and lateral
axis 56 along width W of plate 50. Length L and Width W may have
any measurement desired or necessary to secure bone compression
device 40 the bone(s) desired to be compressed. For example, in
embodiments in which three or more vertebrae are desired to be
compressed, Length L, must be of a distance sufficient to permit
attachment of bone compression device 40 to each vertebrae.
Therefore, length L of plate 50 will be greater in embodiments in
which five vertebrae are to be compressed as compared to
embodiments in which only two vertebrae are to be compressed.
[0041] Plate 50 also includes at least one fastener hole 58 for
receiving fastener (not shown), e.g., bone screws, bolts, etc., to
facilitate securing plate 50 to the bone. Preferably, each fastener
hole is angled such that each fastener is placed through fastener
holes 58 to be secured into the bone at an angle, thereby
facilitating securing plate 50 to the bone. Additionally, multiple
fastener holes 58 are disposed along the length L and width W of
plate 50 as desired or necessary to facilitate securing plate 50 to
the bone. For example, in embodiments in which three or more
vertebrae are to be secured by bone compression device 40, plate 50
will preferably include fastener holes 58 such that at least one
fastener will be inserted and secured to each of the vertebrae.
Therefore, the total number of fastener holes 58 will be dependent
upon the size of plate 50, the number of bones to be compressed,
and the size of the bone(s) to be compressed.
[0042] Generally, plate 50 includes at least one fastener hole 58
disposed near first end 51 and at least one fastener hole 58 near
second end 52. As shown in FIGS. 4-7, plate 50 preferably includes
at least two fastener holes 58 near first end 51 and two fastener
holes 58 near second end 52. An advantage of this embodiment is
that fasteners, e.g., bone screws, may be place through fastener
holes 58 and secured into the bone, and thus securing plate 50 to
the bone, in a manner that lessens the torsional resistance of
plate 50. For example, a first fastener may be used to secure plate
50 to the bone by placing and securing the fastener through the
upper right fastener hole 58 in FIG. 5. Next, a second fastener may
be used to secure plate 50 to the bone by placing and securing the
fastener through the lower left fastener hole 58 in FIG. 5. A third
fastener may then be used to secure plate 50 to the bone by placing
and securing the fastener through the upper left fastener hole 58
in FIG. 5. Thereafter, a fourth fastener may be used to secure
plate 50 to the bone by placing and securing the fastener through
the lower right fastener hole 58 in FIG. 5. All four fasteners may.
Then be tightened as necessary to secure plate 50 to the bone.
[0043] Preferably, plate 50 includes plate interface, e.g., plate
interface hole 57, for receiving a tool, e.g., tensioner 70
discussed in greater detail below, to facilitate handling of plate
50, moving plate 50 from its pre-formed shape to at least one of
its at least one elastic shapes, and placement of plate 50 along
the bone.
[0044] Pre-formed radius of curvature, deformed radius of
curvature, and each of the at least one elastic radius of curvature
therebetween are determined based upon the curvature of plate 50
along longitudinal axis 55 or lateral axis 56. As shown in FIGS. 4
and 6, plate 50 is in its pre-formed shape having pre-formed radius
of curvature defined by the longitudinal curvature of lower surface
54.
[0045] Plate 50 preferably includes at least two attachment members
59. In the embodiment shown in FIGS. 4-5, each attachment member 59
is hole 61. In the embodiment shown in FIGS. 6-7, each attachment
member 59 is loop 62.
[0046] While it is to be understood that the material from which
bone compression device 50 is formed may be any material known to
persons of ordinary skill in the art, the preferred material is
titanium or other material having a relatively low coefficient of
elasticity, thereby reducing the total number of elastic shapes
bone compression device may take. As is readily apparent to those
skilled in the art, the number of elastic shapes the bone
compression device may take will depend on the material from which
bone compression device is formed. Materials having a high
coefficient of elasticity will have many more elastic shapes than a
material having a low coefficient of elasticity Suitable materials
include titanium, titanium-vanadium-aluminum,
cobalt-chromium-molybdenum, as well as any other alloy, metal, or
other material approved by the Food and Drug Administration.
[0047] Additionally, plate 50 may have any two or three dimensional
shape, size, or thickness desired or necessary to be sufficiently
secured to one or more bones.
[0048] As discussed above, plate 50 preferably includes at least
two attachment members, e.g., hole 61 or loop 62, for facilitating
the contouring of plate 50, for example, by string 0 (FIG. 9) and
tensioner 70. As shown in FIG. 8, tensioner 70 includes shaft 71
and spool 72. Spool 72 preferably includes a ratchet (not shown) to
further facilitate winding string 80 around spool 72 and applying
straightening forces to plate 50. Tensioner 70 also preferably
includes at least one plate interface member 73 having interface
member end 74 for interfacing with plate 50, e.g., by inserting at
least one plate interface member 73 into at least one corresponding
plate interface hole 57 disposed along plate 50, to further secure
plate 50 to tensioner 70 thereby facilitating placement of plate 50
along the bone as well as tightening string 80 around spool 72.
Interface member end 74 preferably is shaped to correspond with the
shape of the plate interface. In one embodiment, plate interface
hole 57 is a fastener hole 58. Tensioner 70 may also include handle
75 to facilitate gripping and turning tensioner 70 while tightening
string 80 around spool 72.
[0049] As illustrated in FIG. 9, string 80 includes first end 81
and second end 82 and may be releasably secured to plate 50 through
any manner known to persons skilled in the art. For example, string
80 may be passed through each attachment member 59 and tied in a
knot 86 (FIG. 10). Therefore, after installation of plate 50, each
knot may be cut to release plate 50. Alternatively, as shown in
FIG. 8, first end 81 and second end 82 of sting 80 may include hook
64 to be passed through each attachment member 59 to secure plate
50 during installation. Thereafter, each hook 64 may be removed
from each attachment member 59 thereby releasing plate 50,
[0050] Sting 80 may be formed out of any material know to persons
skilled in the art provided that string 80 is strong enough to
withstand the tensioning forces applied to string 80 during use
without breaking, Preferred materials for forming string 80 include
Kevlar and other polymers having high tensile strength.
[0051] Referring now to FIG. 10, tensioner 70 is placed in contact
with plate 50 by inserting plate interface member 73 into plate
interface hole 57. First end 81 of string 80 is passed through
attachment member 59, i.e., hole 61 in FIG. 10, and tied into knot
86 to secure first end 81 to plate 50. Likewise, second end 82 of
string 80 is passed through attachment member 59, i.e., hole 61 in
FIG. 10, and tied into knot 86 to secure second end 82 to plate
String 80 is then wrapped around spool 72 of tensioner 70.
Tensioner 70 may then be turned in the direction of arrow 90 to
wind, or wrap, string 80 around spool 72. In doing so, string 80
exerts forces on plate 50 whereby place 50 is manipulated, or
moved, in the direction of arrows 91 and 92 (straightening forces)
to at least one of the elastic shapes of plate 50 until the elastic
radius of curvature substantially corresponds to the bone radius of
curvature, i.e., the implantation shape. Plate 50 may then be
installed along one or more bones. After placement of plate 50
along one or more bones, tensioner 70 is turned in the opposite
direction of arrow 90. Therefore, due to hysteresis, plate 50 will
have a tendency to move in the opposite direction of arrows 91 and
92. In doing so, plate 50 will be further secured to the bone or
bones.
[0052] In another aspect, the present invention is directed to
methods of maintaining a bone in a spatial relationship, and in
particular, at least two vertebrae in a spatial relationship with
each other utilizing the bone compression devices discussed above.
With respect to use of the bone compression devices for maintaining
two or more vertebrae is spatial relationship with each other,
first, bone compression device 40 is contoured by mooring bone
compression device 40 from its pre-formed shape to at least one of
the at least one elastic shapes corresponding to the bone radius of
curvature. The bone radius of curvature is formed by the at least
two vertebrae. Bone compression device 40 is then disposed along
the bone radius of curvature and secured to the at least two
vertebrae.
[0053] This method of maintaining at least two vertebrae in a
spatial relationship with each other may be used in connection with
the insertion of at least one bone graft between the at least two
vertebrae prior to securing the bone compression device to the at
least two vertebrae. Accordingly, the bone compression devices
facilitate maintaining the bone graft between the vertebrae as well
as maintaining the at least two vertebrae in a spatial relationship
with each other.
[0054] It is also noted that the bone compression devices may also
be used for maintaining at least three, at least four, and at least
five vertebrae in a spatial relationship with each other. Another
feature of the method of maintaining at least two vertebrae in a
spatial relationship with each other.
[0055] The methods of maintaining at least two vertebrae in a
spatial relationship with each other may also include steps
directed to order in which the fasteners are inserted through the
fastener holes 58. For example, in one embodiment, bone compression
device 40 includes four fastener holes 58 (FIGS. 4-7). The first
fastener hole 58, 101 near first end 51 (upper left in FIGS. 5 and
7) is disposed diagonally from fourth fastener hole 58, 104 near
second end 52 (lower right in FIGS. 5 and 7) and second fastener
hole 58, 102 near first end 51 (upper right in FIGS. 5 and 7) is
disposed diagonally from third fastener hole 58, 103 near second
end 52 (lower left in FIGS. 5 and 7), A first fastener is then
inserted through first fastener hole 58, 101 and first end 51 of
plate 50 is secured to the bone (one of the at least one
vertebrae). A second fastener is then inserted though fourth
fastener hole 58, 104 and second end 52 of plate 50 is secured to
the bone (one of the at least one vertebrae). First end 51 of plate
50 is then further secured to the bone (one of the at least two
vertebrae) with a third fastener inserted through second fastener
hole 58, 102, and second end 52 of plate 50 is further secured to
the bone (one of the at least two vertebrae) with a fourth fastener
inserted through the third fastener hole 58, 103. It is believed
that by inserting the fasteners through the fastener holes 58 to
secure plate 50 to the bone in this manner, torsional resistence is
lessened, thereby increasing the likelihood that bone compression
device 40 will not be loosened over time.
[0056] It is to be understood that the invention is not limited to
the exact details of construction, operation, exact materials, or
embodiments shown and described, as obvious modifications and
equivalents will be apparent to one skilled in the art. For
example, while the bone compression device illustrated and
described above, is discussed in connection with vertebrae, it may
be used to with any other individual bone or bones. The dimensions
and shapes, as well as the means for attaching the bone compression
device to any bone, or number of bones, can be easily determined by
a person of ordinary skill in the art. Moreover, while the bone
compression devices have been described as being installed on the
anterior side of the spine or other bone, the bone compression
devices may be installed on the posterior side of the spine or
other bone. Additionally, the bone compression devices may be
installed on any vertebrae, i.e., lumbar, thoracic, cervical, or
sacral. Further, the lower surface of the plate may include
projections, or spikes, to facilitate securing the plate to the
bone. Moreover, the plate interface member and corresponding plate
interface may be any shape desired or necessary to permit the plate
interface to securely capture the plate interface and thus permit
manipulation and placement of the plate during installation of the
plate. Additionally, the bone compression device may lack a
distinguishable longitudinal axis, e.g., have a squared shape, or
have the preformed, deformed, and elastic radii of curvature
disposed along the width or lateral axis instead of the length or
longitudinal axis. Accordingly, the invention is therefore to be
limited only by the scope of the appended claims.
* * * * *