U.S. patent application number 10/769230 was filed with the patent office on 2004-12-16 for articulated anterior expandable spinal fusion cage system.
Invention is credited to Jackson, Roger P..
Application Number | 20040254643 10/769230 |
Document ID | / |
Family ID | 30443893 |
Filed Date | 2004-12-16 |
United States Patent
Application |
20040254643 |
Kind Code |
A1 |
Jackson, Roger P. |
December 16, 2004 |
Articulated anterior expandable spinal fusion cage system
Abstract
An articulated modular spinal fusion cage is implanted in the
intervertebral space and adjusted in situ from an anterior access
position to support adjacent vertebrae in normal curved alignment.
The cage includes a first leg having a cylindrical pivot member and
a second leg having a socket. The socket permits pivotal movement
of the first leg with respect to the second leg to an anteriorly
open, wedge-shaped orientation which may be selectively angularly
adjusted. The laterally elongated socket and pivot member form a
fulcrum that is positioned anteriorly from the posterior leg ends
to enhance torsional stability and increase anterior preload. A
driver is inserted through a bore in the socket and corresponding
groove in the flange and is operable to engage a sloped interior
surface of the first leg and to urge the anterior end upwardly by
rotating the pivot member within the socket.
Inventors: |
Jackson, Roger P.; (Prairie
Village, KS) |
Correspondence
Address: |
Marcia J. Rodgers, Esq.
Shughart, Thomson & Kilroy, P.C.
Suite 1500
120 W. 12th Street
Kansas City
MO
64105
US
|
Family ID: |
30443893 |
Appl. No.: |
10/769230 |
Filed: |
January 30, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10769230 |
Jan 30, 2004 |
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10292723 |
Nov 12, 2002 |
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6685742 |
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Current U.S.
Class: |
623/17.11 |
Current CPC
Class: |
A61F 2002/448 20130101;
A61F 2002/30774 20130101; A61F 2310/00131 20130101; A61F 2002/30405
20130101; A61F 2002/2835 20130101; A61F 2/30965 20130101; A61F
2002/2817 20130101; A61F 2/447 20130101; A61F 2002/30624 20130101;
A61F 2002/30538 20130101; A61F 2002/30777 20130101; A61F 2250/0006
20130101; A61F 2310/00017 20130101; A61F 2220/0025 20130101; A61F
2002/30507 20130101; A61F 2002/30579 20130101; A61F 2002/30904
20130101; A61F 2310/00023 20130101 |
Class at
Publication: |
623/017.11 |
International
Class: |
A61F 002/44 |
Claims
What is claimed and desired to be secured by Letters Patent is as
follows:
1. A spinal fusion cage apparatus for implanting between adjacent
vertebrae and comprising: a) an inferior leg with an inferior
support surface for supporting engagement with an inferior
vertebra; b) a superior leg with a superior support surface for
supporting engagement with a superior vertebra adjacent said
inferior vertebra; c) said superior leg being pivotally connected
to said inferior leg by a pivot joint having a lateral axis to form
an articulated spinal fusion cage having a posterior end and an
opposed anterior end; d) a threaded driver member adjustably
engaged between said inferior leg and said superior leg to position
said superior leg at a selected angle relative to said inferior
leg; e) said pivot joint being inset a selected distance anteriorly
from said posterior end of said cage to impart a selected spacing
and relative angular relationship between said inferior and
superior vertebrae; f) said pivot joint including a knuckle
positioned on said inferior leg and extending toward said superior
leg, said knuckle having an elongated cylindrical socket extending
laterally thereof; g) said knuckle having a threaded bore formed
therethrough and threadedly receiving said driver member; h) said
pivot joint including a cylindrical pivot member extending
laterally across said superior leg, said pivot member being
received in said knuckle to pivotally connect said superior leg to
said inferior leg; i) said pivot member having a notch formed
therein to enable clearance by said driver member; j) said notch in
said pivot member cooperating with said driver member to prevent
relative lateral displacement of said superior leg and said
inferior leg; k) said superior leg including a sloped inferior
bearing surface; l) said driver member including a head; m) said
driver member head engages said sloped inferior bearing surface to
position said superior leg at a selected angle relative to said
inferior leg; n) said sloped inferior bearing surface including a
groove for receiving said driver member; o) said inferior and
superior support surfaces including ports for permitting bone cells
to grow therethrough and fuse said inferior and superior vertebrae;
p) said inferior and superior support surfaces each including
serrations for preventing disengagement of said spinal fusion cage
from said inferior and superior vertebrae; and q) said superior leg
including a stop structure for abutting engagement with said
inferior leg.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 10/292,723 entitled ARTICULATED ANTERIOR
EXPANDABLE FUSION CAGE SYSTEM, now U.S. Pat. No. 6,685,742.
BACKGROUND OF THE INVENTION
[0002] The present invention is broadly concerned with a spinal
fusion cage system. More particularly, it is directed to an
articulated implant which can be installed between a pair of
adjacent vertebrae and selectively expanded in situ to form a wedge
with an adjustable angle of inclination for supporting and
stabilizing the vertebrae in normal curved alignment in order to
promote fusion of the aligned vertebrae.
[0003] The spine is a column of stacked vertebrae which are
normally axially aligned along the median plane. When viewed from
the front or back, the spine appears to be straight. When viewed
from a lateral perspective, however, it is shown to be comprised of
four distinct curves. Each vertebra is angularly displaced in the
coronal plane in accordance with its position along one of the
respective curves.
[0004] The structure of each vertebra includes a rounded, weight
bearing anterior element, or vertebral body, which is separated
from the adjacent superior and inferior vertebral bodies and
cushioned by fibrocartilage pads or discs. These intervertebral
discs support the adjacent vertebrae in an appropriate angular
orientation within a respective spinal curve and impart flexibility
to the spine so that it can flex and bend yet return to its
original compound curvate configuration.
[0005] Aging, injury or disease may cause damage to the discs or to
the vertebrae themselves. When this occurs, it may be necessary to
surgically remove a disc and fuse the adjacent vertebral bodies
into a single unit. Such surgical arthrodesis is generally
accomplished by implanting a cage-like device in the intervertebral
or disc space. The cages are apertured, and include a hollow
interior chamber which is packed with live bone chips, one or more
gene therapy products, such as bone morphogenic protein, cells that
have undergone transduction to produce such a protein, or other
suitable bone substitute material. Following implantation, bone
from the adjacent vertebrae above and below the cage eventually
grows through the apertures, fusing with the bone of the adjacent
vertebral bodies and fixing the adjacent vertebrae as well as the
cage in position.
[0006] Once the disc has been removed from the intervertebral
space, the angular orientation of the adjacent vertebrae is
established and stabilized by the three dimensional geometry of the
implanted fusion cage, and the vertebrae will eventually fuse in
this orientation. The lumbar curve presents a region of normal
anterior convexity and posterior concavity or lordosis. There is a
need for an anterior implant for use in this region which can be
adjusted in situ to achieve and maintain normal lordosis of the
vertebrae.
[0007] Previous attempts to achieve normal spinal curvature with
fusion cages have involved trial insertion of cages of various
different sizes into the intervertebral space. The cage is
repeatedly removed and replaced with another unit of a slightly
different size until an optimal angular incline is achieved. There
is a need for a modular and articulated implant which can be
installed in a first configuration, and adjusted in situ into a
wedge configuration from an anterior access position.
[0008] Once installed in an intervertebral space, spinal implants
are subject to compressive forces exerted by gravity and movement
of the spinal column. Normal forward bending activity exerts
substantially greater compressive force on the vertebrae than
backward bending. Consequently, there is a need for an implant
which will accept an increased anterior preload to withstand
anterior compressive forces and to maintain the disc space
height.
[0009] Spinal implants are also subject to twisting forces caused
by unequal lateral distribution of weight on the adjacent vertebral
bodies. This may occur, for example, during normal sideward bending
and reaching activity. There is also a need for an implant which
will provide torsional stability to resist such twisting forces. In
particular, in order to withstand the greater compressive forces
associated with forward bending movements, there is a need for an
implant that will provide enhanced anterior torsional
stability.
[0010] The apparatus of the present invention is specifically
designed to provide a modular intervertebral implant which can be
both installed and selectively expanded in situ from an anterior
access position to form a wedge which stabilizes the adjacent
vertebrae in normal curved alignment while providing lateral
stability, increased anterior preload and enhanced anterior
torsional stability.
SUMMARY OF THE INVENTION
[0011] The present invention is directed to an articulated modular
cage system for implantation in the intervertebral space and
adjustment in situ from an anterior access position to support the
adjacent vertebrae in a normal curved alignment while permitting
fusion of the adjacent bones. The fusion cage system of the present
invention includes a first leg having a pivot member, a second leg
having a socket for receiving the pivot member and a driver. The
socket permits movement of the first leg about an axis of pivotal
rotation from a closed, parallel insertion position to an
anteriorly open, wedge-shaped orientation which may be selectively
adjusted to provide appropriate angular support. The socket and
pivot member are laterally elongated to provide lateral support.
The pivot member includes a cylindrical notch or aperture, and the
socket includes a threaded bore which are aligned for receiving a
driver.
[0012] The driver is operable to engage a sloped interior surface
of the first leg and to urge the anterior end of the first leg
apart from the anterior end of the second leg while causing the
pivot member to rotate within the socket. Registry of the driver
within both the bore and the aperture serves to prevent lateral
displacement of the pivot member within the socket. The pivot
member and socket are inset or positioned anteriorly of the
posterior ends of the respective legs in order to enhance torsional
stability and to optimize the anterior preload. This is achieved by
decreasing a moment arm length between an effective area of
engagement of the adjacent vertebrae and the location of the
connection between the legs of the cage. Positioning the pivot axis
anterior of the posterior ends of the legs also helps to optimize
the intervertebral spacing and angular alignment of the adjacent
vertebrae to avoid undesirably stressing the next vertebrae beyond
the vertebrae engaged by the fusion cage.
[0013] Objects and advantages of this invention will become
apparent from the following description taken in conjunction with
the accompanying drawings wherein are set forth, by way of
illustration and example, certain embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a partially exploded perspective view of an
articulated expandable spinal fusion cage system in accordance with
the present invention, illustrating a threaded driver.
[0015] FIG. 2 is a fragmentary side elevational view of the cage of
FIG. 1 installed between adjacent vertebrae, showing a bore and
interior surfaces in phantom to illustrate the path of installation
of the driver.
[0016] FIG. 3 is a view similar to FIG. 2, illustrating the driver
installed between the bearing surfaces of the legs and the anterior
portions of adjacent vertebrae displaced to achieve lordosis.
[0017] FIG. 4 is a front elevational view taken along line 4-4 of
FIG. 3 showing an anterior end of the top leg with the driver
omitted.
[0018] FIG. 5 is a rear elevational view taken along line 5-5 of
FIG. 3 showing a posterior end of the top leg with the driver
omitted.
[0019] FIG. 6 is a bottom plan view taken along line 6-6 of FIG. 2,
showing a bottom side of the top leg of the cage with the driver
omitted.
[0020] FIG. 7 is a front elevational view taken along line 7-7 of
FIG. 3 showing an anterior end of the bottom leg with the driver
omitted.
[0021] FIG. 8 is a top plan view taken along line 8-8 of FIG. 2
showing a top side view of the bottom leg with the driver
omitted.
[0022] The drawings constitute a part of this specification and
include exemplary embodiments of the present invention and
illustrate various objects and features thereof.
DETAILED DESCRIPTION OF THE INVENTION
[0023] As required, detailed embodiments of the present invention
are disclosed herein; however, it is to be understood that the
disclosed embodiments are merely exemplary of the invention, which
may be embodied in various forms. Therefore, specific structural
and functional details disclosed herein are not to be interpreted
as limiting, but merely as a basis for the claims and as a
representative basis for teaching one skilled in the art to
variously employ the present invention in virtually any
appropriately detailed structure.
[0024] Certain terminology will be used in the following
description for convenience in reference only and is not intended
to be limiting. For example, the words "anterior", "posterior",
"superior" and "inferior" and "lateral" and their derivatives will
refer to the device as it may be installed in anatomical position
as depicted in FIGS. 2-3.
[0025] Referring now to the drawings, an articulated anterior
expandable spinal fusion cage system in accordance with the
invention is generally indicated by the reference numeral 1 and is
depicted in FIGS. 1-8. FIGS. 2 and 3 illustrate a partial side view
of a human spine showing an intervertebral region 2, which is the
functional location of implantation of the fusion cage system 1,
between the vertebral bodies of selected upper and lower adjacent
vertebrae 3 and 4.
[0026] Referring again to FIG. 1, the fusion cage system 1 broadly
includes a fusion cage 10 and a driver 11. The cage 10 includes a
first leg 12 depicted and normally installed in a superior
orientation and adjustably coupled with a second, normally inferior
leg 13 by a pivot joint or bearing 14 positioned posteriorly of a
centerline C, passing midway between the ends. The first leg 12 has
an anterior end 15, a posterior end 16 and a pair of opposed sides
20 interconnected by a central web portion 21. The sides of the
cage 20 are depicted as generally planar and orthogonal to the web
portion 21, although they may also be of curvate, angular or
compound curvate or angular construction. The legs 12 and 13 are
normally of the same width and length, but it is also foreseen that
either of the legs 12 and 13 may be of somewhat broader
construction in order to selectively enhance the superior or
inferior bone-supporting surface area.
[0027] The first leg 12 includes an outer, bone-supporting surface
22 and an inner surface 23, best shown in FIG. 6. The web 21 is
apertured by one or more ports or windows 24, which extend between
the outer and inner surfaces 22 and 23.
[0028] The leg inner surface 23 includes an anterior portion 30 and
a posterior portion 31. The anterior portion 30 has a linear cam or
bearing surface 32 that terminates posteriorly in a first abutment
surface or stop 33 that is generally orthogonal to the outer
surface 22. When viewed from the side (FIGS. 1-3), the bearing
surface 32 slopes downwardly at an angle as it approaches the
second end 16 in the configuration of a ramp or wedge having the
abutment surface 33 as its base. The posterior portion 31 extends
in generally parallel relationship with the web outer surface 22
except for a dependent, generally cylindrical pivot member 34
having a pivot axis P. The pivot member 34 depends the entire width
of the cage 10 between the sides 20 and includes a central notch,
aperture or groove 35 (FIGS. 4-6) for receiving the driver 11.
[0029] The leg outer surface 22 includes a series of serrations or
teeth 40 for engaging the surface of a respective adjacent vertebra
3 against slippage along an anterior-posterior axis within the
intervertebral joint 2. The leg inner surface 23 is generally
smooth. The anterior bearing surface 32 is axially grooved to form
a channel 41 (FIG. 6) adapted for sliding reception of the driver
11.
[0030] The second leg 13 has an anterior first end 42, a posterior
second end 43 and a pair of opposed sides 44 interconnected by a
central web portion 45. The leg 13 also includes an outer,
bone-supporting surface 50 and an inner surface 51, best shown in
FIG. 8. The web 45 is apertured by one or more ports or windows 52,
which extend between the outer and inner surfaces 50 and 51.
[0031] The leg inner surface 51 includes an anterior portion 53 and
a posterior portion 54. The anterior portion 53 has a support
surface 55 that extends in generally parallel relationship with the
leg outer surface 50. The posterior portion 54 also extends in
generally parallel relationship with the leg outer surface 50,
except for an upstanding, approximately rectangular knuckle 60. The
knuckle 60 is elongated laterally, so that it extends the full
width of the cage 10 between the sides 44.
[0032] The knuckle 60 includes anterior, posterior, and upper or
superior surfaces 61, 62 and 63 (FIG. 3). The superior surface 63
includes a laterally extending, generally cylindrical channel which
serves as a socket 64 for receiving the cylindrical pivot member 34
of the first leg 12 in pivoting relationship to form the pivot
bearing 14. The laterally elongated pivot member 34 and socket 64
cooperatively provide lateral support to the cage 10 against
sideward bending stresses which may be brought to bear following
installation.
[0033] The anterior and posterior knuckle surfaces 61 and 62 are
generally orthogonal to the outer surface 50, and the anterior
surface 61 serves as an abutment surface or stop for the first leg
abutment surface 33. The upper knuckle surface 63 is generally
parallel with the outer surface 50, except that the posterior
aspect is somewhat relieved so that it does not serve as a stop
when the first leg 12 pivots in the socket 64 of the second leg 13.
As shown in FIGS. 7 and 8, the knuckle 60 includes a central bore
65 having flighting or threads 70 for receiving and engaging the
driver 11.
[0034] Like the first leg 12, the second leg outer surface 50
includes a series of bone-engaging serrations or teeth 71 (FIG. 2).
The leg inner surface 51 is generally smooth. The first and second
leg anterior portions 15 and 42 cooperatively define an open-sided
chamber 72 when the cage 10 is assembled as depicted in FIGS.
1-3.
[0035] The driver 11 is depicted in FIG. 1 to include a radially
expanded head 73 and a shaft 74 terminating in a generally
flattened driving end 75. The shaft 74 is sized and shaped for
reception within channel 41, and preferably includes threads 80 for
operable reception within matingly threaded bore 65, with the
radially expanded driver head 73 engaging the angled bearing
surface 32 of the upper leg 12. It is also foreseen that in certain
applications the shaft 74 could be smooth and unthreaded. The
driver head 73 is coupled with the shaft 74 by a generally
frustoconical shank portion 81, and terminates in a narrow,
generally cylindrical bearing surface 82. The head 73 also includes
a non-round socket or receiver 83 configured for non-slip reception
of a driving tool such as a wrench (not shown). While the receiver
83 is depicted as being generally hexagonal in shape, it is
understood that it may be configured as a square, slot,
multi-lobular or any other shape corresponding to a preselected
driving tool.
[0036] The diameter of the driver head 73 and the length of the
shaft 74 are sized so that the driver 11 extends posteriorly
through the channel 41 of the upper leg 12 for driving registry of
the shaft 74 within the groove 35 of the first leg and central bore
65 of the lower leg 13 and engagement of the driver head bearing
surface 82 with the angled bearing surface 32 of the upper leg 12.
In this manner, the channel 41, groove 35 and bore 65 cooperate
with the shaft 74 of the driver 11 to effectively lock the legs 12
and 13 against lateral displacement.
[0037] The legs 12 and 13 and driver 11 may be constructed of a
non-metallic material such as carbon fiber reinforced composite or
tissue-derived polymer material, or of a strong, inert material
having a modulus of elasticity such as a metal, like stainless
steel or titanium alloy, or of porous tantalum or any other
biocompatible material or combination of materials. It is foreseen
that it may be desirable in certain applications to employ a
radiolucent material such as carbon fiber reinforced composite
which will not block post operative radiographic images of bridging
bone growth.
[0038] It is also foreseen that the fusion cage system 1 may also
include a pair of independently adjustable cages 10, installed in
generally side-by-side relationship within a single intervertebral
space 2, as set forth more fully in U.S. Pat. No. 6,454,807 and
incorporated herein by reference.
[0039] In use, the anterior surface of a selected intervertebral
region 2 of the spine of a patient is surgically exposed. The soft
tissues are separated, the disc space is distracted and the disc is
removed, along with any bone spurs which may be present. The disc
space is distracted to a predetermined height which serves to
decompress any affected nerve roots and to permit preparation of
the intervertebral region 2.
[0040] The fusion cage system 1 is assembled by a surgeon or
assistant by laterally aligning the cylindrical pivot member 34 of
the first leg 12 with the socket 64 of the second leg 13 and
sliding the pivot member 34 laterally into engagement with the
socket 64 until the groove 35 is aligned with the bore 65. The
driver 11 is next grasped and the threaded end 75 is introduced
into the bore 65 and rotated by hand or with the use of an
insertion tool until the threads 80 of the driver shaft 74 engage
the threads 70 of the bore 65. Registry of the driver 11 within
both the groove 35 of the first leg 12 and the bore 65 of the
second leg serves to prevent any lateral movement or play of the
pivot member 34 within the socket 64. The driver 11 may be rotated
a few additional turns in order to secure against disengagement
from the bore 65 during insertion. However, unless the
intervertebral space 2 is substantially larger than the cage 10,
rotation is generally stopped when the conical shank 81 engages the
bearing surface 32 of the first leg 12, so that the cage 10 can be
inserted in its smallest, or closed configuration.
[0041] The first and second leg anterior first ends 15 and 42 are
next grasped and pressed together until the first leg abutment
surface 33 comes to rest against the second leg abutment surface or
stop 61 and the cage 10 is maximally compressed. The assembled
fusion cage 10 presents a closed, overall rectangular
configuration, with the outer surfaces 22 and 50 of the legs 12 and
13 in a generally parallel orientation, as depicted in FIGS. 1 and
2 and the driver 11 projecting slightly anteriorly from the cage
10.
[0042] The cage 10 may be press-fit directly into the distracted
intervertebral region 2, or the vertebrae 3 and 4 may be predrilled
to receive the cage system 1. Although an anterior approach is
preferred, it is foreseen that a posterior or even lateral approach
could also be employed.
[0043] The surgeon next positions a tool (not shown) in the driver
head 73 and rotates the tool in a clockwise or posteriorly
advancing direction to drive or pull the threaded shaft 74 further
into the bore 52 and advance the head 73 in a posterior direction.
Continued rotation of the driver 11 simultaneously causes the end
75 to advance posteriorly, the pivot member 34 to rotate within the
socket 64, and the bearing surface 32 of the first leg 12 to ride
up over the beveled shank 81 until the bearing surface 82 of the
driver 11 engages the bearing surface 32 of the first leg 12. In
this manner, rotational advancement of the driver 11 causes it to
progressively wedge the bearing surface 32 apart from the support
surface 55 of the second leg 13 until the cage 10 begins to assume
a generally wedge shape when viewed from the side.
[0044] In this manner, the angle formed by the outer, bone
supporting surfaces 22 and 50 of the legs 12 and 13, is determined
by the displacement of the bearing surfaces 32 of the first leg 12
away from the support surface 55 of the second leg 13, which in
turn is determined by the posterior advancement of the driver
bearing surface 82 along the first leg bearing surface 32. The
driver 11 is of a preselected size to cause displacement of the
first leg 12 to form the cage 10 into an appropriate wedge shape
which will support the adjacent vertebrae 3 and 4 at the proper
height as well as the desired angular alignment to achieve normal
curvature of the respective spinal region.
[0045] Advantageously, the laterally elongate cylindrical
configuration and anteriorly inset or forward positioning of the
pivot bearing 14 cooperatively formed by the pivot member 34 and
socket 64, relative to the posterior ends 16 and 43 of the legs 12
and 13, enhance both the lateral and torsional stability of the
cage system 1 as well as its anterior preload. The configuration of
the channel 41 for receiving the driver shaft 74 and the anterior
preload also cooperate to enhance torsional stability.
[0046] The surgeon next transplants a quantity of packed bone cells
or a suitable bone substitute material into the chamber 72 by a
lateral approach through the open area between the first and second
legs 12 and 13. Alternatively, the bone cells may be introduced
into the chamber 72 by a posterior approach through the bore 65
prior to installation of the driver 11 or by any combination of
these methods. Bone for use in the graft may be harvested from the
patient as live bone, from a bone bank or from a cadaver.
Demineralized bone matrix, bone morphogenic protein or any other
suitable material may also be employed.
[0047] Following implantation, the bone grows between vertebrae 3
and 4, through the windows 24 and 52 with the bone in the chamber
72 and around the cage system 1 to fuse the bodies of vertebrae 3
and 4 together.
[0048] Those skilled in the art will appreciate that the fusion
cage 10 may also be assembled and installed into the intervertebral
space 2 prior to insertion of the driver 11 into the bore 65. In
addition, while a single exemplary driver 11 and cage 10 having a
wedge-shaped first leg 12 is depicted, a variety of drivers 11 and
cages 10, having variously configured bearing surfaces 32 of
different shapes, each producing a different degree of displacement
of the first leg 12 may be incorporated in a set to allow the
surgeon to preselect a cage system 1 to achieve a desired angle of
displacement and consequent positioning of the vertebrae 3, 4
relative to each other. It is foreseen that various other
configurations of the pivot bearing 14 could be advantageously
employed in the cage system 1.
[0049] The cage system 1 of the invention is designed to permit
adjustment by rotation of the driver 11 in situ until the desired
alignment between the vertebra 3 and 4 is achieved. However, if
necessary, the cage system 1 may also be removed and the
installation repeated using a cage 10 and driver 11 having
different configurations until the desired angular alignment is
achieved.
[0050] It is to be understood that while certain forms of the
present invention have been illustrated and described herein, it is
not to be limited to the specific forms or arrangement of parts
described and shown.
* * * * *