U.S. patent application number 10/189309 was filed with the patent office on 2004-01-08 for intervertebral support device and related methods.
Invention is credited to Duarte, Luis.
Application Number | 20040006390 10/189309 |
Document ID | / |
Family ID | 29999650 |
Filed Date | 2004-01-08 |
United States Patent
Application |
20040006390 |
Kind Code |
A1 |
Duarte, Luis |
January 8, 2004 |
INTERVERTEBRAL SUPPORT DEVICE AND RELATED METHODS
Abstract
An intervertebral support device may include a body having
opposing first and second end faces, opposing top and bottom-faces
extending between the first and second end faces, and opposing side
faces extending between the first and second end faces. A first
diagonal direction may be defined between a first vertical corner
at the first end face and a diagonally opposite second vertical
corner at the second end face, and a second diagonal direction
defined between a second vertical corner at the first end face and
a diagonally opposite first vertical corner at the second end face.
The body may have a tapering height decreasing from the first end
face to the second end face, and while also tapering more quickly
in the first diagonal direction than the second diagonal direction
to provide a corrected angle of spinal curvature upon positioning
between adjacent vertebral bodies in a human spine.
Inventors: |
Duarte, Luis; (San Angelo,
TX) |
Correspondence
Address: |
ALLEN, DYER, DOPPELT, MILBRATH & GILCHRIST P.A.
1401 CITRUS CENTER 255 SOUTH ORANGE AVENUE
P.O. BOX 3791
ORLANDO
FL
32802-3791
US
|
Family ID: |
29999650 |
Appl. No.: |
10/189309 |
Filed: |
July 2, 2002 |
Current U.S.
Class: |
623/17.11 |
Current CPC
Class: |
A61F 2/30965 20130101;
A61F 2310/00011 20130101; A61F 2/28 20130101; A61F 2002/30904
20130101; A61F 2310/00359 20130101; A61F 2002/30266 20130101; A61F
2230/0082 20130101; A61F 2/447 20130101; A61F 2002/30772 20130101;
A61F 2002/30841 20130101; A61F 2002/30281 20130101; A61F 2002/30593
20130101; A61F 2230/0086 20130101; Y10S 606/907 20130101 |
Class at
Publication: |
623/17.11 |
International
Class: |
A61F 002/44 |
Claims
That which is claimed is:
1. An intervertebral support device for providing a corrected angle
of spinal curvature upon positioning between adjacent vertebral
bodies of a human spine, the intervertebral support device
comprising: a body having opposing first and second end faces,
opposing top and bottom faces extending between the first and
second end faces, and opposing side faces extending between the
first and second end faces, a first diagonal direction defined
between a first vertical corner at the first end face and a
diagonally opposite second vertical corner at the second end face,
a second diagonal direction defined between a second vertical
corner at the first end face and a diagonally opposite first
vertical corner at the second end face; said body having a tapering
height decreasing from the first end face to the second end face,
and while also tapering more quickly in the first diagonal
direction than the second diagonal direction, to thereby provide
the corrected angle of spinal curvature upon positioning between
adjacent vertebral bodies of the human spine.
2. The intervertebral support device of claim 1 wherein said body
is generally rectangular.
3. The intervertebral support device of claim 1 wherein said body
has an axis; and wherein the opposing first and second end faces
are canted at respective angles from perpendicular to the axis of
said body.
4. The intervertebral support device of claim 3 wherein the first
and second end faces are canted at greater than about 10.degree.
from perpendicular to the axis of said body.
5. The intervertebral support device of claim 3 wherein the
respective angles of canting of the first and second end faces are
substantially equal.
6. The intervertebral support device of claim 1 wherein said body
has serrations defined on at least one of the top, bottom, and side
faces.
7. The intervertebral support device of claim 1 wherein said body
has at least one spike on at least one of the top, bottom, and side
faces.
8. The intervertebral support device of claim 1 wherein said body
has at least one cavity defined therein for vertebral bone
ingrowth.
9. The intervertebral support device of claim 1 wherein the tapered
height defines a taper angle less than about 10.degree. from the
first end face to the second end face.
10. The intervertebral support device of claim 9 wherein the
tapered height defines a taper angle in a range of about
3-5.degree. from the first end face to the second end face.
11. The intervertebral support device of claim 1 wherein edge
portions of at least one of the first and second end faces are
rounded over.
12. The intervertebral support device of claim 1 wherein said body
is hollow.
13. The intervertebral support device of claim 1 further comprising
a support within said body for supporting at least one of the
faces.
14. The intervertebral support device of claim 1 wherein said body
comprises a skeletal frame.
15. The intervertebral support device of claim 1 wherein said body
comprises at least one of bone, metal, carbon fiber, and PEAK.
16. An intervertebral support device for providing a corrected
angle of spinal curvature upon positioning between adjacent
vertebral bodies of a human spine, the intervertebral support
device comprising: a body having an axis, opposing first and second
end faces, and opposing top and bottom faces extending between the
first and second end faces; said body having a tapered height
decreasing from the first end face to the second end face, and the
opposing first and second end faces being canted at respective
angles from perpendicular to the axis of said body to thereby
provide the corrected angle of spinal curvature upon positioning
between adjacent vertebral bodies of the human spine.
17. The intervertebral support device of claim 16 wherein said body
is generally rectangular.
18. The intervertebral support device of claim 16 wherein the first
and second end faces are canted at greater than about 10.degree.
from perpendicular to the axis of said body.
19. The intervertebral support device of claim 16 wherein the
respective angles of canting of the first and second end faces are
substantially equal.
20. The intervertebral support device of claim 16 wherein said body
has serrations defined on at least one of the top, bottom, and side
faces.
21. The intervertebral support device of claim 16 wherein said body
has at least one spike on at least one of the top, bottom, and side
faces.
22. The intervertebral support device of claim 16 wherein said body
has at least one cavity defined therein for vertebral bone
ingrowth.
23. The intervertebral support device of claim 16 wherein the
tapered height defines a taper angle less than about 10.degree.
from the first end face to the second end face.
24. The intervertebral support device of claim 23 wherein the
tapered height defines a taper angle in a range of about
3-5.degree. from the first end face to the second end face.
25. The intervertebral support device of claim 16 wherein edge
portions of at least one of the first and second end faces are
rounded over.
26. A method for providing a corrected angle of curvature to a
spine in a human patient, the method comprising: positioning an
intervertebral support device between adjacent vertebral bodies in
the spine and transverse to an imaginary vertical plane bisecting
the spine and normal to the posterior thereof to thereby provide
the corrected angle of spinal curvature.
27. The method of claim 26 further comprising: forming an incision
in the patient's back to one side of the imaginary vertical plane;
and inserting the support device through the incision at an
insertion angle relative to the imaginary vertical plane.
28. The method of claim 27 wherein the insertion angle is greater
than about 10.degree..
29. The method of claim 27 wherein the insertion angle is in a
range of about 15-30.degree..
30. The method of claim 26 further comprising removing at least
some of a spinal disc between the vertebral bodies prior to
positioning.
31. The method of claim 26 wherein positioning comprises
positioning the support device from the posterior of the spine.
32. The method of claim 26 wherein positioning comprises
positioning the support device from the anterior of the spine.
33. The method of claim 26 wherein the intervertebral support
device comprises a body having an axis, opposing first and second
end faces, and opposing top and bottom faces extending between the
first and second end faces, the body also having a tapered height
decreasing from the first end face to the second end face, and the
opposing first and second end faces being canted at respective
angles from perpendicular to the axis of the body to thereby
provide the corrected angle of spinal curvature upon positioning
between adjacent vertebral bodies of the human spine.
34. The method of claim 33 wherein the first and second end faces
are canted at greater than about 10.degree. from perpendicular to
the axis of the body.
35. The method of claim 26 wherein the intervertebral support
device comprises a body having opposing first and second end faces,
opposing top and bottom faces extending between the first and
second end faces, and opposing side faces extending between the
first and second end faces, a first diagonal direction defined
between a first vertical corner at the first end face and a
diagonally opposite second vertical corner at the second end face,
a second diagonal direction defined between a second vertical
corner at the first end face and a diagonally opposite first
vertical corner at the second end face, the body having a tapering
height decreasing from the first end face to the second end face,
and while also tapering more quickly in the first diagonal
direction than the second diagonal direction, to thereby provide
the corrected angle of spinal curvature upon positioning between
adjacent vertebral bodies of the human spine.
36. A method for providing a corrected angle of curvature to a
spine in a human patient, the method comprising: positioning an
intervertebral support device between adjacent vertebral bodies in
the spine, the intervertebral support device comprising a body
having opposing first and second end faces, opposing top and bottom
faces extending between the first and second end faces, and
opposing side faces extending between the first and second end
faces, a first diagonal direction defined between a first vertical
corner at the first end face and a diagonally opposite second
vertical corner at the second end face, and a second diagonal
direction defined between a second vertical corner at the first end
face and a diagonally opposite first vertical corner at the second
end face; the body having a tapering height decreasing from the
first end face to the second end face, and while also tapering more
quickly in the first diagonal direction than the second diagonal
direction, to thereby provide the corrected angle of spinal
curvature upon positioning between adjacent vertebral bodies of the
human spine.
37. The method of claim 36 wherein the body is generally
rectangular.
38. A method for providing a corrected angle of curvature to a
spine in a human patient, the method comprising: positioning an
intervertebral support device between adjacent vertebral bodies in
the spine, the intervertebral support device comprising a body
having an axis, opposing first and second end faces, and opposing
top and bottom faces extending between the first and second end
faces; the body having a tapered height decreasing from the first
end face to the second end face, and the opposing first and second
end faces being canted at respective angles from perpendicular to
the axis of the body to thereby provide the corrected angle of
spinal curvature upon positioning between adjacent vertebral bodies
of the human spine.
39. The method of claim 38 wherein the first and second end faces
are canted at greater than about 100 from perpendicular to the axis
of the body.
40. The method of claim 38 wherein the respective angles of canting
of the first and second end faces are substantially equal.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of medical
devices, and, more particularly, to spinal implants and related
methods.
BACKGROUND OF THE INVENTION
[0002] A normal human spine has two curves called the kyphotic
curve and the lordotic curve. The kyphotic curve is the outward
curve of the thoracic vertebrae (at the level of the ribs). The
lordotic curve is the inward curve of the lumbar vertebrae (just
above the buttocks).
[0003] A small degree of both kyphotic and lordotic curvature is
normal, but in some circumstances these curves may become
exaggerated. Exaggeration of the kyphotic curve is called
Scheuermann's disease, and this condition results in rounded or
hunched shoulders. Exaggeration of the lordotic curve is called
lordosis, or more commonly "swayback." Depending upon the severity
of the case, medical (i.e., surgical) intervention is sometimes
required to correct the abnormal curvature associated with
Scheuermann's disease and lordosis. Similarly, medical intervention
is frequently required for a third type of scoliotic or sideways
curvature of the spine called scoliosis.
[0004] To this end, numerous types of spinal implant devices have
been developed to correct or modify an angle of spinal curvature.
For example, U.S. Pat. No. 6,277,149 to Boyle et al. discloses a
ramp-shaped intervertebral implant formed from the diaphysis or
metaphysis of a long bone or other biocompatible material. The
implant may also have ridges defined on top and bottom surfaces
thereof to help hold the implant in place. Additionally,
perforations may be formed along any of the surfaces of the implant
to facilitate bone ingrowth.
[0005] Another similar implant is disclosed in U.S. Pat. No.
6,302,914 to Michelson, which also has serrations for holding the
insert in place as well as holes to allow bone in-growth. Other
examples of wedge-shaped or tapered implants are disclosed in U.S.
Pat. Nos. 6,045,580 and 6,315,795 both to Scarborough et al.;
5,984,922 to McKay; and 6,117,174 to Nolan; and in Published
application Nos. 2001/0031965 to Zucherman et al. and 2001/0008980
to Gresser et al. Each of these implants is designed to be used in
pairs, i.e., one is to be inserted on each side of the center of
the spine between two vertebral bodies so that both halves of the
spine are supported.
[0006] While the above devices may be effective for correcting
spinal curvature, their insertion may in some instances be quite
obtrusive to the patient. That is, to insert two implants between
vertebral bodies may require more than one incision by the surgeon
as well as movement of several back muscles, ligaments, etc. As a
result, significant trauma may be experienced by the patient, which
can not only increase his pain but also prolong recovery.
Additionally, using multiple spinal implants may be expensive, and
they may require a relatively long time for a surgeon to insert in
a patient.
SUMMARY OF THE INVENTION
[0007] In view of the foregoing background, it is therefore an
object of the present invention to provide an intervertebral
support device which provides correction for conditions such as
lordosis, Scheuermann's disease, and scoliosis, while causing less
trauma to a patient during implantation.
[0008] This and other objects, features, and advantages in
accordance with the present invention are provided by an
intervertebral support device for providing a corrected angle of
spinal curvature upon positioning between adjacent vertebral bodies
of a human spine. The intervertebral support device may include a
body having opposing first and second end faces, opposing top and
bottom faces extending between the first and second end faces, and
opposing side faces extending between the first and second end
faces. Furthermore, a first diagonal direction may be defined
between a first vertical corner at the first end face and a
diagonally opposite second vertical corner at the second end face,
and a second diagonal direction defined between a second vertical
corner at the first end face and a diagonally opposite first
vertical corner at the second end face.
[0009] As such, in certain embodiments the body may have a tapering
height decreasing from the first end face to the second end face,
and while also tapering more quickly in the first diagonal
direction than the second diagonal direction. The intervertebral
support device thereby provides the corrected angle of spinal
curvature upon positioning between adjacent vertebral bodies of the
human spine. In other embodiments, the body may alternately (or in
addition) have an axis, and the opposing first and second end faces
may be canted at respective angles from perpendicular to the axis
of the body to thereby provide the corrected angle of spinal
curvature upon positioning between adjacent vertebral bodies of the
human spine. By way of example, the body may be generally
rectangular in shape.
[0010] More particularly, the first and second end faces may be
canted at greater than about 10.degree. from perpendicular to the
axis of the body. Further, the respective angles of canting of the
first and second end faces may be substantially equal. Also, the
body may further include opposing side faces, and the body may have
one or more spikes and/or serrations defined on at least one of the
top, bottom, and side faces. The body may further have at least one
cavity defined therein for vertebral bone ingrowth.
[0011] The tapered height may define a taper angle less than about
10.degree. from the first end face to the second end face, and,
more preferably, in a range of about 3-5.degree.. Also, edge
portions of at least one of the first and second end faces may be
rounded over. In certain embodiments, the body may be hollow, and
it may also have a support therein for supporting at least one of
the sides. The body may also be a skeletal frame, and it may
include at least one of bone, metal, carbon fiber, and PEAK, for
example.
[0012] A method aspect of the invention is for providing a
corrected angle of curvature to a spine in a human patient. The
method may include positioning an intervertebral support device,
such as the one described briefly above, between adjacent vertebral
bodies in the spine and transverse to an imaginary vertical plane
bisecting the spine and normal to the posterior thereof to thereby
provide the corrected angle of spinal curvature. As such, only a
single support device need be used to provide support to both sides
of the spine. Thus, less trauma may be required to implant the
device as compared to the prior art devices noted above, and the
patient may therefore feel less pain following surgery and recover
more rapidly.
[0013] By way of example, the insertion angle may be greater than
about 10.degree., and more preferably in a range of about
15-30.degree. (and even up to about 90.degree. for certain surgical
techniques). The method may also include removing at least some of
a spinal disc between the vertebral bodies prior to positioning.
Additionally, the support device may be positioned from the
posterior or anterior of the spine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a side view of a human spine having an
intervertebral support device in accordance with the present
invention inserted therein to correct an angle of spinal
curvature.
[0015] FIG. 2 is a top view of a human vertebra illustrating the
insertion of an intervertebral support device in accordance with
the invention.
[0016] FIG. 3 is a perspective view of the intervertebral support
device of FIG. 1.
[0017] FIG. 4 is a side view of the intervertebral support device
of FIG. 1.
[0018] FIG. 5 is top plan view of the intervertebral support device
of FIG. 1 illustrating respective angles of canting of first and
second end faces thereof.
[0019] FIG. 6 is a perspective view of an alternate embodiment of
the intervertebral support device according to the invention.
[0020] FIG. 7 is a perspective view of another alternate embodiment
of the intervertebral support device according to the
invention.
[0021] FIG. 8 is a side view of still another alternate embodiment
of the intervertebral support device according to the
invention.
[0022] FIG. 9 is a perspective view of yet another alternate
embodiment of the intervertebral support device according to the
invention.
[0023] FIG. 10 is a top view similar to FIG. 2 illustrating another
alternate embodiment of the intervertebral support device according
to the present invention.
[0024] FIG. 11 is a perspective view of the intervertebral support
device of FIG. 10.
[0025] FIG. 12 is a flow diagram illustrating a method for
providing a corrected angle of curvature of a spine in a human
patient in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] The present invention will now be described more fully
hereinafter with reference to the accompanying drawings, in which
preferred embodiments of the invention are shown. This invention
may, however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. Rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. Like numbers refer to like
elements throughout, and prime and multiple prime notation are used
to indicate similar elements in alternate embodiments.
[0027] Referring initially to FIGS. 1-5, an intervertebral support
device 20 in accordance with the present invention will now be
described. The intervertebral support device 20 is for providing a
corrected angle of spinal curvature upon positioning between
adjacent vertebrae 21 of a human spine 41 in the back 22 of a
patient 23. As used herein, "corrected" angle means any desired
modification to an angle of spinal curvature, as will be
appreciated by those of skill in the art.
[0028] As will also be appreciated by those of skill in the art,
each vertebra 21 includes a vertebral body 24, a lamina 25
connected thereto and defining the spinal canal 26 therebetween,
and transverse processes 27 and spinal processes 28 connected to
the lamina. In accordance with the present invention, the
intervertebral support device 20 is particularly well suited for
insertion between two adjacent vertebral bodies 24 to provide a
corrected angle of spinal curvature, as will be described further
below. By way of comparison, an incorrect angle of lordotic
curvature is illustratively shown in FIG. 1 with a dashed line 42,
which is in contrast to the corrected angle of the spine 41
provided by the intervertebral support device 20.
[0029] The intervertebral support device 20 includes a body having
an axis 30 and having opposing first and second end faces 31, 32,
respectively. The body also includes opposing top and bottom faces
33, 34, respectively, and opposing side faces 35, 36 extending
between the first and second end faces 31, 32, to thereby define a
generally rectangular shape. Other sides (not shown) may be
included in some embodiments to provide different body shapes, such
as hexagons, octagons, etc., as will be understood by those of
skill in the art.
[0030] Moreover, the body illustratively has a tapered height
decreasing from the first end face 31 to the second end face 32.
This tapered height defines a taper angle .beta. shown in FIG. 4.
Furthermore, as may particularly be seen with respect to FIG. 5,
the opposing first and second end faces 31, 32 are preferably
canted at respective angles .theta., .gamma. from perpendicular to
the axis 30. The above described tapering (i.e., angle .beta.) and
canting of the first and second end faces 31, 32, are selected to
provide the corrected angle of spinal curvature upon positioning
between adjacent vertebral bodies 24 in the spine 41, as will be
described further below.
[0031] The angle .beta. corresponds to the desired angle of
correction of spinal curvature required between a given pair of
vertebral bodies 24. The taper may vary depending upon the
particular spinal condition to be corrected, i.e., lordosis,
Scheuermann's disease, scoliosis, etc. That is, the angle .beta.
will vary depending upon where the intervertebral support device 20
is to be placed (e.g., between lower lumbar or upper thoracic
vertebrae 21) and the amount of correction that is required. The
intervertebral support device 20 need not always be used to remedy
extreme cases such as scoliosis or Scheuermann's disease, rather
slight correction may be provided in some applications to simply
maintain normal lordosis and/or sagittal alignment. By way of
example, the angle .beta. of the taper will typically be less than
about 10.degree. from the first end face 31 to the second end face
32, and in the case of lordosis correction may typically be in a
range of about 3-5.degree., although other angles may also be
used.
[0032] Of course, the intervertebral support device 20 may include
other tapers as well, such as from one of the opposing sides 35, 36
to the other (not shown), for example. Such additional tapers may
make the intervertebral support device 20 particularly useful for
correcting scoliosis, for example. That is, the taper represented
by the angle .beta. may be used to correct the scoliotic curve,
while the side-to-side taper may allow the proper kyphotic/lordotic
curve to be maintained, as will be appreciated by those of skill in
the art. Further, while a linear taper is illustratively shown in
FIG. 4, non-linear tapers may also be used in some embodiments.
[0033] The first and second end faces 31, 32 are preferably canted
such that the canting angles .theta., .gamma. are greater than
about 10.degree. from perpendicular to the axis 30 of the body. In
the embodiment illustrated in FIG. 4, for example, the respective
angles of canting .theta., .gamma. of the first and second end
faces 31, 32 are substantially equal. Of course, in other
embodiments these angles may be different.
[0034] In one particularly advantageous embodiment, the angles
.theta., .gamma. may be set such that the first and second end
faces 31, 32 are substantially parallel to the back 22 of the
patient 23 when inserted at a predetermined insertion angle .alpha.
illustratively shown in FIG. 2, as will be described further below.
This orientation allows the desired height to be maintained
adjacent the anterior of the vertebrae 21 as well as adjacent the
spinal canal 26 when the intervertebral support device 20 is
positioned at the insertion angle .alpha.. This would not be
possible with the prior art devices described above, since
inserting a single one of these devices at such an angle would
cause the taller of the two ends thereof to protrude too far
inwardly toward the center of the vertebral bodies 24. As a result,
the amount of kyphotic/lordotic correction provided may not match
the taper of the device, plus this may result in an unwanted
scoliotic curve and/or unequal support for both sides of the spine
41.
[0035] Dimensions of the intervertebral support device 20 may be
defined as follows. Using a length m for the major sides of the
bottom face 34, a length n for the major sides of the top face 33,
a height of 11 mm for the first end face 31 and a height of 9 mm
for the second end face 32, the shape of the top face may be
defined according to the following relationship:
2x-m.multidot.cos 20.degree..multidot.z=-9m.multidot.cos
20.degree., (1)
[0036] where m may be any desired length, and n={square
root}{square root over (m.sup.2+4)}. The height values 9 mm and 11
mm were selected in the above example to provide a 3-5.degree.
angle of lordosis, although other values may be used as well for
these heights. It will also be noted in the above example that the
canting angles .theta., .gamma. are both 20.degree., although here
again other angles may also be used.
[0037] Numerous alternate embodiments of the invention are
illustrated in FIGS. 6-9. Elements not specifically mentioned, but
indicated by prime or multiple prime notation, are similar to those
described above and need no further discussion herein. The body 20'
illustrated in FIG. 6 includes serrations 50 on the opposing sides
35', 36', as well as edge portions 51 of the second end face 32'
which are rounded over. Of course, edge portions of the first end
face 31' (or other edges of the body) may be rounded over as well,
if desired.
[0038] In the embodiment illustrated in FIG. 7, the body 20" may
include one or more spikes 60. Both the serrations 50 and spikes 60
may be used to help hold the respective intervertebral support
devices 20', 20" in place upon positioning between adjacent
vertebral bodies 24, as will be appreciated by those of skill in
the art. Of course, serrations 50 and/or spikes 60 may be included
on any face of the body. The body 20" may further have at least one
cavity 61 defined therein for vertebral bone ingrowth to provide an
arthrodesis support device. The cavity may extend all the way
through the body from the top face 33" to the bottom face 34", or
only part way.
[0039] In another embodiment the intervertebral support device 20'"
may be a skeletal frame, as illustratively shown in FIG. 8. The
intervertebral support device 20'" may further include a support 70
for supporting at least one face thereof.
[0040] Yet another embodiment is illustrated in FIG. 9 in which the
intervertebral support device 20"" is hollow. The intervertebral
support device 20"" may also include one or more supports 70 as
well in some embodiments. The body may be made of any suitable
biocompatible material such as bone, metal (e.g., titanium), carbon
fiber, and/or PEAK, for example. Obviously, materials such as bone
may be desirable if fusion between the vertebral bodies 24 and
intervertebral support device 20 is required.
[0041] Turning now additionally to FIGS. 10 and 11, still another
embodiment of the intervertebral support device 20'"" will now be
described. In the illustrated embodiment, the intervertebral
support device 20'"" is similar to that described above with
respect FIG. 2 with the exception that the first and second end
faces 31'"", 32'"" are not canted. Rather, a first diagonal
direction D1 (illustrated with a dashed line) is defined between a
first vertical corner 110'"" at the first end face 31'"" and a
diagonally opposite second vertical corner 111'"" at the second end
face 32'"". Additionally, a second diagonal direction D2 (also
illustrated with a dashed line) is defined between a second
vertical corner 112'"" at the first end face 31'"" and a diagonally
opposite first vertical corner 113'"" at the second end face
32'"".
[0042] In accordance with the present embodiment, the body not only
has a tapering height decreasing from the first end face 31'"" to
the second end face 32'"", but it also tapers more quickly in the
first diagonal direction D1 than in the second diagonal direction
D2 to thereby provide the corrected angle of spinal curvature upon
positioning between adjacent vertebral bodies 24'"", as may best be
seen in FIG. 11. Of course, those of skill in the art will
appreciate that in certain embodiments the intervertebral support
device 20'"" may also have canted first and second end faces 31'"",
32'"", as well as one or more of the other features described above
(spikes, serrations, rounded end faces, bone ingrowth cavities,
etc.). The remaining elements illustrated in FIGS. 6-11 and not
specifically mentioned herein are similar to those described above
and will therefore not be discussed further.
[0043] The intervertebral support device 20 may be manufactured
according to a variety of different techniques. For example, with
certain of the above materials a mold may be used. Of course, other
techniques may include forming a block of the desired material
(e.g., a rectangular block) and planning or cutting the block to
form the canted first and second end faces 31, 32 and the tapered
height therebetween. Other suitable manufacturing techniques known
to those of skill in the art may also be used.
[0044] A method aspect of the invention for providing a corrected
angle of curvature of a spine 41 in a human patient 23 using the
above described intervertebral support device 20 will now be
described with respect to FIG. 12. The method begins (Block 90)
with forming an incision at a point 29 in the patient's back 22 to
one side of an imaginary vertical plane 40, which bisects the spine
41 and is normal to the posterior thereof (FIG. 2), at Block 91.
Generally, it will be necessary to remove some or all of the spinal
disk 43 between the vertebral bodies 24, at Block 92, as well as
move certain back muscles/ligaments to allow for insertion of the
intervertebral support device 20, as will be appreciated by those
of skill in the art.
[0045] Thereafter, the intervertebral support device 20 may be
inserted though the incision at the insertion angle a, which is
measured relative to the imaginary vertical plane 40, at Block 93.
In particular, by inserting the intervertebral support device 20 at
the insertion angle ac, the intervertebral support device may be
relatively easily positioned to traverse the imaginary vertical
plane 40, at Block 94. As such, only a single support device 20
need be used to provide support to both sides of the spine 41, as
will be appreciated by those of skill in the art. Accordingly, less
trauma may be required to implant the intervertebral support device
20 as compared to the prior art devices noted above. Thus, the
patient may feel less pain following surgery and recover more
rapidly.
[0046] Of course, more that one intervertebral support device 20
may be used, either between the same two adjacent vertebral bodies
40 or between different pairs of adjacent bodies along the spine
41, as will be appreciated by those of skill in the art. A variety
of suitable surgical techniques known to those skilled in the art
may be used for performing the steps illustrated at Blocks 91-94,
and such steps will therefore not be discussed further herein.
[0047] By way of example, the insertion angle .alpha. may be
greater than about 10.degree., and more preferably may be in a
range of about 15-30.degree.. Insertion angles of up to about
90.degree. (or other angles) may even be used for some surgical
techniques. Although a posterior insertion has been described, it
should be noted that positioning of the intervertebral support
device 20 from the side or anterior of the spine 41 may also be
performed, if desired. The method concludes (Block 95) upon closing
the incision in the patient's back 22 by any suitable surgical
technique, as will be understood by those skilled in the art. It
should be noted that although the preceding method has been
described as using the intervertebral support device 20 for clarity
of explanation, any of the above-described embodiments thereof (or
others which will be apparent to those of skill in the art) may
also be used.
[0048] Many modifications and other embodiments of the invention
will come to the mind of one skilled in the art having the benefit
of the teachings presented in the foregoing descriptions and the
associated drawings. Therefore, it is understood that the invention
is not to be limited to the specific embodiments disclosed, and
that modifications and embodiments are intended to be included
within the scope of the appended claims.
* * * * *