U.S. patent application number 13/493032 was filed with the patent office on 2012-11-15 for prosthetic implant with biplanar angulation and compound angles.
This patent application is currently assigned to X-SPINE SYSTEMS, INC.. Invention is credited to David Louis Kirschman.
Application Number | 20120290091 13/493032 |
Document ID | / |
Family ID | 42241485 |
Filed Date | 2012-11-15 |
United States Patent
Application |
20120290091 |
Kind Code |
A1 |
Kirschman; David Louis |
November 15, 2012 |
PROSTHETIC IMPLANT WITH BIPLANAR ANGULATION AND COMPOUND ANGLES
Abstract
A prosthetic implant, and more particularly, with a prosthetic
implant having biplanar angulation and that can be inserted into a
disk area generally straight using a posterolateral approach.
Inventors: |
Kirschman; David Louis;
(Dayton, OH) |
Assignee: |
X-SPINE SYSTEMS, INC.
Miamisburg
OH
|
Family ID: |
42241485 |
Appl. No.: |
13/493032 |
Filed: |
June 11, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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12336753 |
Dec 17, 2008 |
8216316 |
|
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13493032 |
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Current U.S.
Class: |
623/17.16 |
Current CPC
Class: |
A61F 2002/4629 20130101;
A61F 2002/30616 20130101; A61F 2002/30617 20130101; A61F 2/4611
20130101; A61F 2/447 20130101; A61F 2002/3082 20130101; A61F
2002/30785 20130101; A61F 2002/30841 20130101; A61F 2002/30904
20130101; A61F 2002/2835 20130101; A61F 2250/0097 20130101 |
Class at
Publication: |
623/17.16 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. A fusion cage comprising: a cage body having a plurality of
surfaces; said plurality of surfaces cooperating to define a
multi-planar angulation adapted to achieve substantially flush
fitment in a disk space between adjacent vertebrae when said fusion
cage is inserted in said disk space.
2-31. (canceled)
32. A method for fusing bones, said method comprising the steps of:
providing a cage adapted to be inserted into a disk area
substantially diagonally or in an angled direction with respect to
an anterior-posterior axis, said cage having a first surface lying
in a first plane and a second surface lying in a second plane; and
inserting said cage in said substantially diagonal or angled
direction such that said first and second surfaces engage a surface
of a first vertebrae and a second vertebrae substantially
flush.
33. The method as recited in 32 wherein said method further
comprises the step of: providing a cage having said first and
second surfaces that cooperate to define a compound angle to
provide a biplanar angulation.
34. The method as recited in 32 wherein said method further
comprises the step of: providing a cage having a cage body
comprising a longitudinal plane along a longitudinal axis and a
cross-sectional plane along a cross-sectional axis that is
generally perpendicular to said longitudinal axis, said cage body
not being volumetrically symmetrical about either of said
longitudinal plane or said cross-sectional plane.
35. The method as recited in claim 32 wherein said method further
comprises the step of: providing a cage having a first surface and
a second surface and a first side and a second side coupling said
first and second surfaces; said first side defining a first side
area, said second side defining a second side area, wherein said
first and second side areas are different.
36. The method as recited in claim 32 wherein said method further
comprises the step of: providing a cage that defines a trapezoid or
trapezium in a cross-sectional plane that is generally
perpendicular to a longitudinal axis.
37. The method as recited in claim 32 wherein said method further
comprises the step of: providing a cage having a first surface
generally opposed to a second surface, said first and second
surfaces defining a compound angle and cooperating to define a
biplanar angulation.
38. The method as recited in claim 37 wherein said method further
comprises the step of: providing a cage with said first surface
lying in a first plane and said second surface lying in a second
plane, said first and second planes being non-parallel and defining
a plurality of acute angles.
39. The method as recited in claim 32 wherein said inserting step
occurs during a posterolateral approach.
40. The method as recited in claim 32 wherein said method further
comprises the step of providing a plurality of different sized
cages from which a user selects said cage.
41. A prosthetic implant system comprising: a fusion cage
comprising a cage body having a plurality of surfaces, said
plurality of surfaces cooperating to define a multi-planar
angulation adapted to achieve substantially flush fitment in a
lordotic disk space between adjacent vertebrae when said fusion
cage is inserted in said lordotic disk space; and an insertion tool
for securing to said fusion cage to permit a user to insert and
place said fusion cage into a disk area using a posterolateral
approach.
42-52. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/336,753, filed Dec. 17, 2008, which is
incorporated herein by reference and made a part hereof.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a prosthetic implant, and more
particularly, with a prosthetic implant having a biplanar
angulation to permit insertion straight along a diagonal angle into
a disk space.
[0004] 2. Description of the Related Art
[0005] Spinal fusion is a commonly performed procedure. In a
typical spinal fusion operation, a surgeon places a mechanical
container, commonly known as a cage, between at least two adjacent
vertebrae of the spine. This container contains or is later filled
with bone graft which eventually incorporates into the adjacent
vertebrae and creates a solid fusion. Interbody cages are placed in
the disk space following removal of the disk. The cage can be
surgically placed via several approaches, such as anteriorly
through the abdomen, posteriorly through the spinal canal,
posterolaterally through the neuroforamen of the vertebra, and
transversely from a side of the spine. A goal of the surgical
approach is to minimize trauma to adjacent structures and incision
size.
[0006] A challenge to the placement of cages is the attainment of
proper fitment between the adjacent vertebrae. It is important that
a cage surface fits flushly against the endplates of the adjacent
vertebrae. If a cage fits poorly, the cage could loosen, causing
poor fixation and potential re-operation. The disk space, where the
cage is placed, is not parallel. The space is angulated such that
it is wider anteriorly than posteriorly. This angulation is termed
lordosis.
[0007] Several cage designs have been proposed in the prior art.
Brantigan (U.S. Pat. No. 4,834,757) describes a square shaped cage
which is impacted in between vertebrae. Michelson (U.S. Pat. No.
5,015,247) describes a straight threaded cage which is screwed into
the disk space. Brantigan (U.S. Pat. No. 5,425,772) and Michelson
(U.S. Pat. No. 6,302,914) describe a cage with a built in
single-plane lordotic angle to improve fitment between adjacent
vertebrae. These cages are designed for posterior or anterior
placement.
[0008] The placement of cages from posterior, lateral, and anterior
approaches raise concerns about potential impingement upon
important anatomical structures. Such structures are the spinal
canal, the spinal nerves, and the abdominal vasculature,
respectively. The posterolateral approach, also called the
transforamenal approach, is gaining popularity as the preferred
approach for the placement of intervertebral fusion cages.
Typically, cages designed for this approach are "banana shaped," as
exemplified by Varga, et al (U.S. Pat. No. 6,579,318).
[0009] A significant difficulty with banana-type cages is that
their placement requires cage rotation at the time of placement to
seat the cage in place. The cage is inserted at a 45 degree lateral
angle into the disk space (the maximum angle limited by anatomical
structures) and is then rotated a further 45 degrees within the
disk space for proper placement. This rotational step is difficult
in that it occurs blindly inside the disk space. Incomplete
rotation frequently occurs, resulting in poor cage fitment, with
potential loosening and reoperation.
[0010] If a Brantigan (U.S. Pat. No. 4,834,757) cage were inserted
in a diagonal or non-straight trajectory, it would not have flush
contact with the adjacent vertebrae due to the lordotic angle of
the disk space. Furthermore, a standard lordotic cage, such as
Michelson (U.S. Pat. No. 6,302,914), would have its lordotic angle
in the incorrect orientation for proper fitment if placed
diagonally.
[0011] What is needed is a cage that can be placed via the
posterolateral approach in a straight manner and that does not
require a further rotation for placement. Desirably, such a cage
will be placed at a straight angle relative to an
anterior-posterior axis and, preferably, at a diagonal or angle,
such as approximately 45 degrees and reside in a diagonal
configuration within the disk space.
SUMMARY OF THE INVENTION
[0012] Accordingly, one object of the invention is to provide a
cage having a biplanar angulation.
[0013] Another object of the invention is to provide a cage that
has a biplanar angulation and that may be inserted straight into a
disk space, at an angle or diagonally relative to the
anterior-posterior axis of the spine.
[0014] Still another object of the invention is to provide a cage
having a biplanar angulation and that minimizes or eliminates the
need for rotation after the cage is inserted into the disk
space.
[0015] Yet another object of the invention is to provide a cage
having lateral slots or channels for insertion of a tool or
instrument to facilitate placement of the cage.
[0016] In one aspect, this invention comprises a fusion cage
comprising a cage body having a plurality of surfaces, the
plurality of surfaces cooperating to define a multi-planar
angulation adapted to achieve substantially flush fitment in a disk
space between adjacent vertebrae when the fusion cage is inserted
in the disk space.
[0017] In another aspect, this invention comprises a method for
fusing bones, the method comprising the steps of providing a cage
adapted to be inserted into a disk area substantially diagonally or
in an angled direction with respect to an anterior-posterior axis,
the cage having a first surface lying in a first plane and a second
surface lying in a second plane, and inserting the cage in the
substantially diagonal or angled direction such that the first and
second surfaces engage a surface of a first vertebrae and a second
vertebrae substantially flush.
[0018] These and other objects and advantages of the invention will
be apparent from the following description, the accompanying
drawings and the appended claims.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0019] FIG. 1 is a perspective view of a cage in accordance with
one embodiment of the invention showing the cage placed in a disk
space;
[0020] FIG. 2 is a view, taken along the line 2-2 in FIG. 1,
showing the cage inserted straight and at a diagonal or an angle
with respect to an anterior-posterior axis;
[0021] FIG. 3 is a perspective view showing various details of the
cage shown in FIGS. 1 and 2;
[0022] FIG. 4 is another perspective view of the cage of FIG.
1;
[0023] FIG. 5 is a perspective view of the cage with various
projection lines showing the dimensional relationships between the
various line segments to illustrate the biplanar angulation or
compound angles formed by the various surfaces of the cage;
[0024] FIG. 5A is view showing imaginary planes corresponding to
the superior and inferior surfaces of the cage, showing their
relative relationship and multi-planar or bi-planer angulation;
[0025] FIG. 5B is a view, taken in the direction of arrow A in FIG.
5A, showing the relationship of the planes and biplanar angulation
of the surfaces;
[0026] FIG. 6 is a front view of the cage;
[0027] FIG. 7 is a rear view of the cage;
[0028] FIG. 8 is a side view of the cage shown in FIG. 1, showing
the various relationships and dimensions and relative dimensions of
the various corners of the cage;
[0029] FIGS. 9 and 10 are illustrative embodiments showing
different multi-planar or biplanar angulations;
[0030] FIG. 11 is a cross-sectional view taken along the line 11-11
in FIG. 5;
[0031] FIG. 12 is a diagonal view taken along the line 12-12 in
FIG. 5;
[0032] FIG. 13 is a sectional view taken along the line 13-13 in
FIG. 5;
[0033] FIG. 14 is a fragmentary exploded perspective view of a
portion of a cage and an insertion tool;
[0034] FIG. 15 is a perspective view of yet another embodiment of
the cage of FIG. 1;
[0035] FIG. 16 is a front view of the cage;
[0036] FIG. 17 is a rear view of the cage;
[0037] FIG. 18 is a perspective view of the cage similar to FIG.
5;
[0038] FIGS. 19A and 19B are views similar to FIGS. 5A and 5B,
respectively;
[0039] FIG. 20A illustrates a cage placed in a space between two
disks;
[0040] FIG. 20B is a view taken along line 20B-20B of FIG. 20A;
[0041] FIG. 20C is a view taken along line 20C-20C of FIG. 20A;
[0042] FIG. 20D is a view taken along line 20D-20D of FIG. 20A;
[0043] FIG. 21A is a view similar to FIG. 20A showing use of
another cage;
[0044] FIG. 21B is a view taken along line 21B-21B of FIG. 21A;
[0045] FIG. 21C is a view taken along line 21C-21C of FIG. 21A;
[0046] FIG. 21D is a view taken along line 21D-21D of FIG. 21A;
[0047] FIG. 22A is a view similar to FIGS. 20A and 21A;
[0048] FIG. 22B is a view taken along line 22B-22B of FIG. 21A;
[0049] FIG. 22C is a view taken along line 22C-22C of FIG. 21A;
[0050] FIG. 22D is a view taken along line 22D-22D of FIG. 21A;
and
[0051] FIG. 23 is a is a perspective view of another embodiment of
the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0052] Referring now to FIGS. 1-10, a prosthetic implant or fusion
cage 10 is shown for insertion and use in a disk space or disk area
11 between a first vertebra 12 and second vertebra 14. In the
illustration being described, the first vertebra 12 has a first or
superior surface 12a and the second vertebra 14 has a second or
inferior surface 14a, as best illustrated in FIG. 1. The cage 10 is
inserted straight posterolaterally, also called a transforamenal
approach, into the disk area 11 between the first vertebra 12 and
second vertebra 14. As described and shown, the cage 10 is inserted
on a diagonal or angled direction with respect to an
anterior-posterior axis AP (FIG. 2), such as in the direction of
arrow 16 as shown.
[0053] Notice in FIGS. 3 and 4 that the cage 10 comprises a
superior or top surface 18 and a generally opposing inferior or
bottom surface 20. In the illustration being described, note that
the surfaces 18 and 20 are serrated or comprise teeth 22 to
facilitate preventing the cage 10 from loosening or becoming
displaced after the cage 10 is placed in the disk area 11 between
the first vertebra 12 and the second vertebra 14. The cage 10 is
adapted or configured to comprise the surfaces 18 and 20 that
cooperate to define a biplanar angulation and that cooperate to
define multiple angles or at least one compound angle as described
herein. The relative angulation between surfaces 18 and 20
facilitate full or flush surface contact between the vertebrae
surfaces 12a and 14a and the surfaces 18 and 20, respectively, of
the cage 10.
[0054] As illustrated in FIGS. 3 and 4, the surfaces 18 and 20
comprise an interior wall 18a and 20a, respectively, that define
generally oval apertures or openings 24 and 26, for receiving bone
graft material. Note that the cage 10 further comprises a front
portion, surface or end 28 and a rear surface or end 30 as shown.
The front portion, surface or end 28 comprises a plurality of
angled surfaces 28c and 28d, as shown, that cooperate to define a
nose, prow or angled frontal portion for ease of substantially
straight or linear insertion and placement into the disk area 11
using a posterolateral or transforamenal approach.
[0055] The rear surface or end 30 comprises an interior wall 30a
having a threaded aperture 40 for receiving an instrument or bone
graft material after the cage 10 is inserted substantially straight
or linearly into the disk area 11 using the posterolateral or
transforamenal approach.
[0056] The cage 10 further comprises a side or third surface 42 and
a generally opposing side or fourth surface 44 as shown. Note that
the third surface 42 comprises a plurality of interior walls 42a
and 42b that define apertures 46 and 48, respectively. Similarly,
fourth surface 44 comprises interior walls 44a and 44b that define
apertures 50 and 52, respectively, as shown. As illustrated, the
apertures 46 and 48 are generally opposed to the apertures 50 and
52, respectively, and provide lateral openings adapted to permit
graft material to be inserted into an open cage area 54 for fusing
the vertebrae 12 and 14 together. Thus, it should be understood
that the bilateral openings or apertures 46, 48, 50 and 52
facilitate insertion of bone graft material (not shown) and for
bone ingrowth. The inferior and superior openings 24 and 26 further
facilitate bone ingrowth.
[0057] The surfaces 42 and 44 each comprise a plurality of
generally U-shaped walls or surfaces 42c, 42d and 44c, 44d,
respectively, to define a first lateral slot 60 and a second
lateral slot 62, respectively, for facilitating the placement of
the cage 10 using an insertion tool or a surgical instrument 61
(FIG. 14). Notice that the lateral slots 60 and 62 are asymmetrical
to allow for directional coupling to an insertion tool or surgical
instrument 61. In this regard, notice that the slot 60 has a
dimension D1 that is greater than a dimension D2 of the slot 62.
The lateral slots 60 and 62 are adapted to receive a generally
complementary shaped inter-fitting members or projections 63 and
65, respectively, of the insertion tool or surgical instrument
61.
[0058] The insertion tool or surgical instrument 61 has a hollow
tubular portion 61 a that receives a rotatable shaft extension 67
having an end 69 that is threaded so that it can be screwed or
threaded into the threaded aperture 40, as illustrated. During use,
the surgeon would place the rotatable shaft extension 67 until the
cage 10 becomes secured or fixed to the insertion tool or surgical
instrument 61.
[0059] After placement of the cage 10, the rotatable shaft
extension 67 is rotated counterclockwise from the cage 10. Note
that the insertion tool or surgical instrument 61 or tubular
portion 61 a may have indicia 71 for indicating to the surgeon or
user the proper orientation of the cage 10, thereby reducing or
eliminating the chance that the cage 10 would be improperly placed,
for example, upside down into the disk area 11.
[0060] Referring now to FIGS. 3-10, the relative relationship of
the surfaces 18 and 20, multiplanar or biplanar angulation and
compound angle(s) they define will now be described. For ease of
illustration, FIGS. 5-10 show various line projections or line
segments corresponding to lines or segments between various
boundary corners or points or edges of the cage 10. The points are
identified and labeled with the letters A-F. The various
relationships between and/or among the line segments and other
segments will be used for ease of understanding to illustrate or
demonstrate the biplanar angulation or compound angles of the cage
10 in this illustration. The ">" designation is understood to
mean that a dimension of a segment is larger than the dimension of
the segment(s) to which it is compared, "<" means the dimension
is less, and "=" means the dimension of the segments is equal. For
example, "CD>AB" means that the portion of the cage 10
associated with line segment CD comprises a dimension that is
greater than the portion of the cage 10 associated with segment
AB.
[0061] Returning to the description in the illustration of FIGS.
5-8, note that the line segment length C-D>A-B>E-F>G-H,
and the area defined by ACDB in FIG. 5 is greater than the area
GEFH. As illustrated in FIGS. 5-8, the dimension between the line
segments A-C and B-D gets smaller when moving from line C-D to A-B.
Likewise, the cage 10 has a compound or biplanar angulation so that
a cross-sectional height dimension (as viewed in FIG. 5) of the
cage 10 gets smaller from segment C-D as it moves to every other
segment A-B, G-H and E-F.
[0062] FIG. 5A illustrates imaginary planes P1 and P2 in which the
surfaces 18 and 20, respectively, lie. FIG. 5B shows a view taken
in the direction of arrow A in FIG. 5A and generally perpendicular
to the plane P2 showing the biplanar angulation or relative tilt
(when viewed from left to right in the FIG. 5B and toward G-H). In
the example, the surfaces 18 and 20 converge along both a
longitudinal axis from a first point, such as the end 28, to a
second point such as the rear surface or end 30. The planes P1 and
P2 and surfaces 18 and 20 also converge in a direction from segment
C-D to G-H in the illustration and also when viewed in a direction
generally perpendicular to that longitudinal axis as shown in FIGS.
5-A, 5B and 5C. Thus, the cage 10 and surfaces 18 and 20 define
numerous angles, such as angles BA1, BA2, BA3 and BA4 shown in FIG.
4. The angles are all different in the illustration.
[0063] Stated another way, the cage 10 comprises a longitudinal
axis LA (FIG. 3) and a cross-sectional axis CSA (FIG. 3) that is
generally perpendicular to the longitudinal axis LA. In the
illustration being described in FIGS. 1-14, the cage 10 is
symmetrical about a longitudinal horizontal plane LHP (FIG. 4)
along the longitudinal center axis (FIG. 3), but is non-symmetrical
in a longitudinal vertical plane LVP (FIG. 3). In one illustration,
the cage 10 assumes a trapezoid (FIG. 11) in a vertical
cross-sectional plane that is generally perpendicular to the
longitudinal center axis, such as the imaginary plane along line
11-11 in FIG. 5. It should be understood, however, that the cage 10
could assume another shape, such as a trapezium (see FIGS. 15-19B),
ellipsoid, circular, oval, arcuate or other shape. Other
illustrative embodiments are shown in FIGS. 15-23 described later
herein.
[0064] One important feature of the cage 10 is that the opposing
surfaces 18 and 20 in the illustration provide, are arranged or are
adapted to cooperate to define one or more compound angles or a
biplanar angulation so that the surfaces 18 and 20 become in
substantially flush contact with the surfaces 12a and 14a,
respectively, when the cage 10 is inserted substantially straight
or linearly on a diagonal or angle into the disk area 11 using a
posterolateral or transforamenal approach and, if necessary,
rotated as described herein.
[0065] FIG. 8 is an illustration corresponding to the embodiments
of FIGS. 3-7 illustrating CD being greater than AB which is greater
than EF which in turn is greater than GH. It should be understood,
however, that the degree of the biplanar angulation or compound
angle will be selected or changed and will depend upon the relative
relationship or orientation between the disk surfaces 12a and 14a.
Several other illustrative embodiments are shown in FIGS. 9-10. For
example, FIG. 9 illustrates an embodiment wherein the cage 10 has
dimensions such that the line segment CD>AB=EF>GH. FIG. 10
illustrates an embodiment where line segment CD>AB<EF>GH.
As described later herein, the user will select the cage 10 having
the desired biplanar angulation in response to the disk area 11 and
the relative relationship of the vertebrae surfaces 12a and 14a.
This selection and placement will now be described.
[0066] During a surgical procedure it should be understood that the
cage 10 is inserted generally straight or linearly at an angle or
on a diagonal trajectory relative to the anterior-posterior axis AP
(FIG. 2) using a posterolateral or transforamenal approach. As
mentioned, the cage 10 and the biplanar angulation or compound
angle(s) defined by surfaces 18 and 20 will be selected and adapted
depending upon the relative relationship between the surfaces 12a
and 14a. In general, the angle .THETA. (FIG. 2) of insertion
increases, the length differences between the segments EF-CD will
be decreased and the length differences between the segments AB-GH
will also be decreased or lesser. In one embodiment, the cage is
being rotated from an angle parallel to the intervertebral lordotic
angle to an angle perpendicular to the intervertebral lordotic
angle. Segments EF-CD and AB-GH no longer have to conform to this
lordotic angle in this trajectory and therefore their length
differences are decreased.
[0067] As a size of the cage 10 increases, a length difference, for
example, between segments EF-CD will be greater as the cage 10 gets
larger because a larger amount of the lordotic angle is covered by
the cage, and segments or dimensions AB-GH will also be greater.
FIGS. 20A-20D, 21A-21D and 22A-22D further illustrate these
concepts. All else being equal, larger cages 10 require larger
segment differences. A tiny cage 10 covers very little length of
the lordosis, so the difference in side length will be small.
[0068] In the illustration in FIGS. 20A-20D, a selected cage 10 is
inserted using a posterolateral or transforamenal approach and
rotated such that its longitudinal axis is generally parallel to
the anterior-posterior axis AP as shown. In this illustration, the
cage 10 may have a relatively large longitudinal angulation (the
angulation BA3 associated with side 42) as illustrated in FIG. 20B.
Note, however, that the surfaces 12a and 14a in the illustration
are angled not only posterolaterally, but also slightly in a
lateral direction (i.e., along a cross-sectional angulation that is
generally perpendicular to the longitudinal axis of the cage 10),
as illustrated in FIG. 20B. Given the slight angulation, the cage
10 may have only a slight cross-sectional angulation (that is, the
angles BA1 and BA2, illustrated in FIGS. 20C and 20D,
respectively).
[0069] FIGS. 21A-21D illustrate a similar relationship between
surfaces 12a and 14a. However, note that the cage 10 is inserted
and rotated or pivoted such that it is angled with respect to the
anterior-posterior center line. In view of this positioning, note
that the user may select a cage 10 wherein the surfaces 12a and 14a
define the angle BA3 that is less than the angle BA3 associated
with the embodiment illustrated in FIG. 20B. Note that the
cross-sectional dimension (i.e., those angles BA1 and BA2
illustrated in FIGS. 21C and 21D) will be slightly larger than
those corresponding angles illustrated in FIGS. 20C and 20D, as
shown.
[0070] FIGS. 22A-22D show another extreme placement of the cage 10,
wherein the cage 10 is situated such that its longitudinal axis is
generally perpendicular to the anterior-posterior axis. In this
position, note that the longitudinal angle is associated with the
side 42 (that is, the angle BA3 in the illustration), but generally
corresponds to the angle (labeled DA in FIG. 22B) defined by the
disk surfaces 12a and 14a. Compare this cage 10 to the cage 10 in
the illustration described earlier herein relative to the
embodiment of FIG. 20B. Note the cage 10 is selected and adapted to
conform to the relationship of the surfaces 12a and 14a as well as
the position in which the cage 10 is going to be inserted into the
disk area 11 between the surfaces 12a and 14a.
[0071] Continuing with the illustration, a cage 10 is shown in
FIGS. 22A-22D, having a longitudinal angulation that is slight, as
illustrated in FIG. 22B, given the lateral placement of the cage 10
in the disk area 11. However note that the cross-sectional
angulation and angles BA1 (FIG. 22C) and BA2 (FIG. 22D) may be
relatively greater when compared to the same angles illustrated in
FIGS. 20C and 20D.
[0072] Advantageously, the implant, system and method provides
means for adapting and selecting a cage 10 in response to the
relationship between the surfaces 12a and 14a as well as the
placement of the cage 10 using a posterolateral approach and the
position of the cage 10 in the disk area 11. In some cases, it may
be necessary to use a cage 10 having larger or smaller longitudinal
angles BA3 and BA4 and smaller cross-sectional angles BA1 and BA2,
while in other environments it may be desired to use a cage 10
having relatively larger cross-sectional angles BA1 and BA2 and
smaller biplanar angles BA3 and BA4. The angles BA1 and BA2 can be
changed relative to each other as can angles BA3 and BA4.
[0073] Thus, it should be appreciated that the invention provides a
cage 10 having biplanar and angulation defining compound angles
that can adapt to various environments such that the surfaces 18
and 20 provide a snug fit against the surfaces 12a and 14a,
respectively.
[0074] As alluded to earlier herein, the cage 10 could assume
different shapes, such as trapezium, ellipsoid, circular, oval,
arcuate or other shapes. In this regard, and as described earlier
herein, the embodiment of FIGS. 1-14 illustrate a cage 10 that is
generally symmetrical about the longitudinal horizontal plane (FIG.
4). FIGS. 15-19B illustrate another embodiment, similar to the
embodiment in FIGS. 1-14 wherein the cage 10 is not symmetrical
about the longitudinal horizontal plane as illustrated in FIGS.
15-17. The parts in this embodiment are the same or similar to the
parts in the embodiments of FIGS. 1-14 and those same or similar
parts have been identified with the same part numbers, except that
a prime mark (" ") has been added to the part numbers of the
embodiment shown in FIGS. 15-19B.
[0075] In this illustrative embodiment, the cage 10 is not
symmetrical about the longitudinal horizontal plane LHP illustrated
in FIGS. 16 and 17, and the surfaces 18, 20, 42 and 44 cooperate to
define a trapezium in cross-section as shown.
[0076] As illustrated in FIG. 18 and as with the embodiment being
described earlier herein, various relationships between the
segments may be defined. For example, as illustrated in FIGS.
15-18, the line segment KL is greater than IJ is greater than MN is
greater than OP and the area defined by IKLJ in FIG. 18 is greater
than the area OMNP. As with the prior embodiment, these various
dimensions and relationships may be changed, modified or adapted to
the particular environment or disk area 11 in which the cage 10 is
going to be used.
[0077] FIGS. 19A-19B are similar to the imaginary planes shown in
FIGS. 5A and 5B. These planes, however, show the non-symmetry of
the surfaces 18 and 20 about the longitudinal horizontal plane. By
comparison, note the planes P1 and P2 illustrated FIG. 5B show the
planes P1 and P2 being generally symmetrical about the longitudinal
horizontal plane. As with the prior embodiment, the cage 10 in FIG.
15 is also asymmetrical about the longitudinal plane.
[0078] FIG. 23 illustrates yet another embodiment of the invention
illustrating a different shape of the cage 10 having biplanar
angulation. In this embodiment, the surfaces 18 and 20 are bowed,
convex or arcuately shaped as shown. Similar parts are identified
with a double prime mark.
[0079] Thus, it should be understood that the cage 10 is selected
and/or adapted to comprise a biplanar angulation and to permit a
posterior-lateral insertion into the disk area 11. The cage 10 is
selected or adapted such that it will provide a flush fitmet in a
lordotic disk space when placed diagonally via a posterolateral
approach. Advantageously, the cage 10 provides biplanar angulation
to allow for full surface contact with the surfaces 12a and 14a of
the adjacent vertebrae 12 and 14, respectively, when placed at the
angled or diagonal trajectory. Note that the cage 10 is inserted in
the angled or diagonal trajectory and that the superior and
inferior cage surfaces 18 and 20 are in flush or substantially
flush engagement with the surfaces 12a and 14a.
[0080] It should be understood that while the embodiments
illustrated in FIGS. 1-10 show a polygonal or multi-sided shaped
cage 10, the cage 10 could take other configurations, such as
elliptical, circular or the like. The important feature is that the
cage 10 is adapted to provide a biplanar angulation of surfaces 18
and 20 that cooperate to define a compound angle or a biplanar
angulation that facilitate a generally or substantially flush fit
against surfaces 12a and 14a, respectively, of the vertebrae during
generally straight insertion using a posterior lateral
approach.
[0081] During use, the insertion tool or surgical instrument 61
(FIG. 14) is screwed to the cage 10 as illustrated in FIGS. 1 and
2, the cage 10 is placed using a posterolateral or transforamenal
approach and inserted into the disk area 11 (FIG. 1) in a generally
straight or linear manner. In the illustration being described, the
cage 10 provides means and apparatus that can be placed via a
posterolateral approach in a relatively straight manner which
reduces or eliminates the need to rotate the cage 10, which can
reduce or minimize incorrect orientation or impingement upon
important anatomical structures, such as the spinal canal, spinal
nerves, abdominal vasculature. The surgeon may use the insertion
tool or surgical instrument 61 (FIG. 14) inserted into the lateral
slots 60 and 62 to facilitate placement and proper positioning.
Note that the nose or front portion 28 of the cage 10 is adapted to
facilitate insertion into the disk area 11. The cage 10 may be
pivoted or rotated to a proper position as suggested in FIGS.
20A-22D. Graft material may be inserted in a conventional manner
into the cage 10. Typically, the graft is placed prior to the
insertion of the cage. The cage 10 is then placed using a
posterolateral or transforamenal approach and rotated or pivoted if
necessary. Thereafter, the patient is closed and the procedure is
finished in a conventional manner.
[0082] Advantageously, the prosthetic implant or fusion cage 10
provides many advantages, some of which include: [0083] a fusion
cage wherein the plurality of surfaces cooperate to define a
biplanar angulation; [0084] a fusion cage wherein the cage body has
a first surface generally opposed to a second surface, the first
and second surfaces cooperating to define a compound angle and
defining a biplanar angulation; [0085] a fusion cage wherein the at
least one of the first or second surfaces are arcuate or convex in
cross-section; [0086] a fusion cage wherein the first surface and
the second surface converge along a longitudinal axis and in a
direction generally perpendicular to the longitudinal axis, the
first and second surfaces cooperating to define the compound angle;
[0087] a fusion cage wherein the first surface lies in a first
plane and the second surface lies in a second plane, the first and
second planes being non-parallel in cross-section along a
longitudinal axis and in cross-section along an axis generally
perpendicular to the longitudinal axis; [0088] a fusion cage
wherein the cage body comprises a longitudinal plane along a
longitudinal axis and a cross-sectional plane along a
cross-sectional axis that is generally non-parallel to the
longitudinal axis, the cage body being non-symmetrical about either
of the longitudinal plane or the cross-sectional plane; [0089] a
fusion cage wherein the cage body comprises a first surface and a
second surface coupling the plurality of surfaces, the first
surface defining a first surface area and the second surface
defining a second surface area, wherein the first and second
surface areas are different; [0090] a fusion cage wherein the cage
body defines a trapezoid or trapezium in a cross-sectional plane
that is generally perpendicular to a longitudinal axis; [0091] a
fusion cage wherein the trapezoid or trapezium gets smaller along
the longitudinal axis from a first end to a second end; [0092] a
fusion cage wherein the cage body defines a second trapezoid or
trapezium in a second cross-sectional plane that is generally
perpendicular to a longitudinal axis, the cross-sectional plane and
the second cross-sectional plane being different in shape or area;
[0093] a fusion cage wherein a first surface of a first vertebrae
cooperates with a second surface of a second vertebrae to define
the disk space, the cage body comprises a top defining a top
surface for engaging the first surface of the first vertebrae and a
bottom surface for engaging the second surface of the second
vertebrae, wherein the cage body is adapted to cause the top and
bottom surfaces of the cage body to engage the first and second
surfaces substantially flush after the fusion cage is inserted into
the disk space at an angled or diagonal trajectory; [0094] a fusion
cage wherein the cage body comprises at least one channel or slot
generally parallel to a longitudinal axis of the cage body, the at
least one channel or slot being adapted for receiving an insertion
instrument; [0095] a fusion cage wherein the cage body comprises at
least one aperture adapted for receiving an insertion instrument;
[0096] a fusion cage wherein the insertion instrument comprises
indicia to facilitate proper placement of the fusion cage; [0097] a
fusion cage wherein the plurality of surfaces comprise a first
surface that lies in a first plane and a generally opposed second
surface that lies in a second plane, the first and second surfaces
cooperating to define a compound angle; [0098] a fusion cage
wherein the compound angle is adapted to cause the first and second
surfaces to engage the first and second vertebrae substantially
flush when the fusion cage is inserted at an angled or diagonal
trajectory into a disk area; [0099] a fusion cage wherein each of
the plurality of surfaces comprises an opening, the cage body
having at least one of a longitudinal slot or an opening adapted to
receive a surgical instrument; [0100] a fusion cage wherein the
cage body comprises a longitudinal axis and a cross-sectional axis,
each of the first and second surfaces cooperating to define a first
angle along the longitudinal axis and a second angle along the
cross-sectional axis, each of the first and second angles being an
acute angle; [0101] a fusion cage wherein the first and second
angles are different; [0102] a fusion cage wherein the cage body is
adapted such that when it is inserted substantially diagonally or
angled with respect to an anterior-posterior axis, the first and
second surfaces engage the first and second vertebrae substantially
flush; [0103] a fusion cage wherein the first and second vertebrae
cooperate to define a second compound angle, the second compound
angle being adapted so that the first and second surfaces engage
the first and second vertebrae substantially flush when the cage
body is inserted into s disk area substantially diagonally or
angled with respect to an anterior-posterior axis; [0104] a fusion
cage wherein the first and second angles are different; [0105] a
fusion cage wherein the cage body comprises a shape that is
polygonal and non-circular in any plane; [0106] a fusion cage
wherein the plurality of surfaces comprises a first planar surface
and a generally opposed second planar surface, the cage body is
symmetrical about a diagonal axis across the first planar surface;
[0107] a fusion cage wherein the fusion cage is symmetrical about a
longitudinal horizontal plane; [0108] a fusion cage wherein the
fusion cage is asymmetrical about a longitudinal horizontal plane;
[0109] a fusion cage wherein the fusion cage is asymmetrical about
a longitudinal vertical plane; [0110] a fusion cage wherein the
fusion cage is asymmetrical about a longitudinal vertical plane;
[0111] a fusion cage wherein the at least one aperture defines a
plurality of lateral slots; [0112] a fusion cage wherein the
plurality of lateral slots comprise different dimensions to receive
a plurality of projections, respectively, of a surgical instrument,
the plurality of projections being adapted or sized to generally
complement a size of the plurality of lateral slots; [0113] a
method for fusing bones wherein the method further comprises the
step of providing a cage having the first and second surfaces that
cooperate to define a compound angle to provide a biplanar
angulation; [0114] a method for fusing bones wherein the method
further comprises the step of providing a cage having a cage body
comprising a longitudinal plane along a longitudinal axis and a
cross-sectional plane along a cross-sectional axis that is
generally perpendicular to the longitudinal axis, the cage body not
being volumetrically symmetrical about either of the longitudinal
plane or the cross-sectional plane; [0115] a method for fusing
bones wherein the method further comprises the step of providing a
cage having a first surface and a second surface and a first side
and a second side coupling the first and second surfaces, the first
side defining a first side area, the second side defining a second
side area, wherein the first and second side areas are different;
[0116] a method for fusing bones wherein the method further
comprises the step of providing a cage that defines a trapezoid or
trapezium in a cross-sectional plane that is generally
perpendicular to a longitudinal axis; [0117] a method for fusing
bones wherein the method further comprises the step of providing a
cage having a first surface generally opposed to a second surface,
the first and second surfaces defining a compound angle and
cooperating to define a biplanar angulation; [0118] a method for
fusing bones wherein the method further comprises the step of
providing a cage with the first surface lying in a first plane and
the second surface lying in a second plane, the first and second
planes being non-parallel and defining a plurality of acute angles;
[0119] a method for fusing bones wherein the inserting step occurs
during a posterolateral approach; [0120] a method for fusing bones
wherein the method further comprises the step of providing a
plurality of different sized cages from which a user selects the
cage; [0121] a prosthetic implant system wherein the fusion cage
has a plurality of slots and the insertion tool comprises a
plurality of projections adapted for receiving in the plurality of
slots; [0122] a prosthetic implant system wherein the plurality of
slots have different dimensions and the plurality of projections
generally complement the shape of the plurality of slots; [0123] a
prosthetic implant system wherein the fusion cage comprises a
threaded aperture, the insertion tool comprising a threaded member
for screwing into the threaded aperture to secure the fusion cage
to the insertion tool; [0124] a prosthetic implant system wherein
the insertion tool comprises indicia to facilitate proper placement
of the fusion cage; [0125] a prosthetic implant system wherein the
fusion cage has a plurality of slots and the insertion tool
comprises a plurality of projections adapted for receiving in the
plurality of slots; [0126] a prosthetic implant system wherein the
plurality of slots have different dimensions and the plurality of
projections generally compliment the shape of the plurality of
slots; [0127] a fusion cage wherein the plurality of surfaces
cooperate to define a biplanar angulation; [0128] a fusion cage
wherein the cage body has a first surface generally opposed to a
second surface, the first and second surfaces cooperating to define
a compound angle and defining a biplanar angulation; [0129] a
fusion cage wherein the at least one of the first or second
surfaces are arcuate or convex in cross-section; [0130] a fusion
cage wherein a first surface and a second surface converge along a
longitudinal axis and in a direction generally perpendicular to the
longitudinal axis, the first and second surfaces cooperating to
define a compound angle; and [0131] a fusion cage wherein a first
surface lies in a first plane and a second surface lies in a second
plane, the first and second planes being non-parallel in
cross-section along a longitudinal axis and in cross-section along
an axis generally perpendicular to the longitudinal axis.
[0132] While the method herein described, and the form of apparatus
for carrying this method into effect, constitute preferred
embodiments of this invention, it is to be understood that the
invention is not limited to this precise method and form of
apparatus, and that changes may be made in either without departing
from the scope of the invention, which is defined in the appended
claims.
* * * * *