U.S. patent application number 15/465143 was filed with the patent office on 2017-09-07 for transforaminal intersomatic cage for an intervertebral fusion graft and an instrument for implanting the cage.
The applicant listed for this patent is LDR Medical. Invention is credited to Reginald James Davis, Greg Hoffman, Jean Huppert, Kevin Kaufman, Alan McGee, Hugues Mousselard, Ludovic Rillardon.
Application Number | 20170252183 15/465143 |
Document ID | / |
Family ID | 37067404 |
Filed Date | 2017-09-07 |
United States Patent
Application |
20170252183 |
Kind Code |
A1 |
Davis; Reginald James ; et
al. |
September 7, 2017 |
Transforaminal intersomatic cage for an intervertebral fusion graft
and an instrument for implanting the cage
Abstract
This present invention concerns a transforaminal intersomatic
cage for an intervertebral fusion graft, and an instrument and
method for implanting the cage, an embodiment of the cage having a
body in the shape of a circular arc and comprising a lateral
concave surface, a lateral convex surface, a straight upper
surface, a straight lower surface and an end wall having at least
one hole, called the end hole, designed to receive a rod of an
instrument for implanting the cage between the vertebrae, wherein:
the end hole has an orientation that is more or less tangential to
the circular arc described by the body; the extremity opposite to
the end wall of the body includes a return part extending the body
toward the centre of the circle on which the circular arc described
by the body lies.
Inventors: |
Davis; Reginald James;
(Cockeysville, MD) ; Kaufman; Kevin; (Fort Worth,
TX) ; Hoffman; Greg; (Fort Wayne, IN) ; McGee;
Alan; (Fort Wayne, IN) ; Huppert; Jean;
(L'Etrat, FR) ; Mousselard; Hugues; (Paris,,
FR) ; Rillardon; Ludovic; (Le Raincy, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LDR Medical |
Sainte-Savine |
|
FR |
|
|
Family ID: |
37067404 |
Appl. No.: |
15/465143 |
Filed: |
March 21, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13854808 |
Apr 1, 2013 |
9597198 |
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15465143 |
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11378165 |
Mar 17, 2006 |
8409288 |
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13854808 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2230/0013 20130101;
A61F 2002/30594 20130101; A61F 2002/30579 20130101; A61F 2002/30795
20130101; A61F 2002/30879 20130101; A61F 2/4455 20130101; A61F
2230/0041 20130101; A61F 2002/30892 20130101; A61F 2/4611 20130101;
A61F 2002/30192 20130101; A61F 2002/30845 20130101; A61F 2002/3008
20130101; A61F 2002/30894 20130101; A61F 2002/4627 20130101; A61F
2002/30576 20130101; A61F 2250/0098 20130101; A61F 2002/30131
20130101; A61F 2002/2835 20130101; A61F 2002/30308 20130101; A61F
2002/30884 20130101; A61F 2230/0063 20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 15, 2006 |
FR |
FR0601315 |
Claims
1-17. (canceled)
18. An instrument for the implantation of an intersomatic cage for
an intervertebral fusion graft comprising a body generally defining
an arc, the body comprising a lateral concave surface; a lateral
convex surface; a substantially transverse upper surface; a
substantially transverse lower surface; an end wall at a first
longitudinal extremity of the body, the end wall comprising an end
hole oriented substantially tangential to the arc defined by the
body; said instrument comprising: a rod comprising a retaining end
configured for insertion in the end hole; a gripping end for
gripping the intersomatic cage, the gripping end comprising a
support spatula comprising a base and generally defining an arc
complementary to the arc defined by the body, a guide tube in which
the rod is slidably disposed and to which the base of the support
spatula is mounted, the guide tube comprising an opening through
which the retaining end of the rod can transit for insertion in the
end hole; and a handling end for manipulating the instrument.
19. An instrument according to claim 18, wherein the rod extends
substantially to the vicinity of the handling end of the
instrument.
20. An instrument according to claim 18, wherein the instrument
comprises a button attached to the rod and a groove through which
the button projects, the button being configured for sliding the
rod to adjust the position of the retaining end of the rod in
relation to the opening in the guide tube.
21. An instrument according to claim 18, wherein the guide tube
comprises a pin configured to engage a recess disposed on the end
wall of the intersomatic cage.
22. An instrument according to claim 18, wherein the support
spatula comprises an end portion distal from the base, the end
portion configured for insertion into a return hole disposed on an
incurvate return part of the intersomatic cage, which return hole
is oriented substantially tangential to the arc defined by the
body.
23. An instrument according to claim 22, wherein the guide tube
comprises a pin configured to engage a recess disposed on the end
wall of the intersomatic cage, the retaining end of the rod, the
pin, and the end portion of the implantation instrument being
configured to cooperate with, respectively, the end hole, the
recess, and the return hole, to secure a grip on the intersomatic
cage by the implantation instrument, and to facilitate the
withdrawal of the instrument following implantation of the
intersomatic cage by removing the retaining end of the rod from the
end hole.
24. An instrument according to claim 18, further comprising an
aiming tube that extends substantially to the vicinity of the
handling end of the instrument, wherein the guide tube comprises a
mobile portion that pivots in relation to the aiming tube at least
in a primary pivot direction, the primary pivot direction lying
substantially within a plane in which the arc defined by the
support spatula lies, and the position of the mobile portion in
relation to the aiming tube defining a pivot angle.
25. An instrument according to claim 24, wherein one of the mobile
portion or the aiming tube comprises a substantially spherical end,
and the other of the mobile portion or the aiming tube comprises a
recessed end having a shape and dimensions complementary to the
shape and dimensions of the spherical end, the spherical end and
the recessed end being configured, respectively, as a ball
component and a socket component of a ball and socket
connection.
26. An instrument according to claim 25, wherein the socket
component comprises opening edge portions, one of which portions is
proximal to the support spatula and is configured to encompass the
ball component less than the other opening edge portions to allow
further pivoting of the mobile portion in relation to the aiming
tube at least in the primary pivot direction.
27. An instrument according to claim 25, wherein the rod is
flexible and slidably transits the ball and socket connection
through a channel located at the centre of the ball component and
the socket component, the channel having a hollowed portion
proximal to the support spatula, the hollowed portion configured to
allow the rod to slide through the ball and socket connection even
when the mobile portion is pivoted in relation to the aiming
tube.
28. An instrument according to claim 24, the instrument further
comprising a lock slidably disposed along the aiming tube, the lock
having a forward position and being configured to fix the mobile
portion of the guide tube at a selected pivot angle when the lock
is disposed in the forward position.
29. An instrument according to claim 28, wherein the mobile portion
comprises a serration configured to increase the maximum pivot
angle at which the mobile portion of the guide tube can be fixed by
the lock and to provide a pre-determined pivot angle.
30. An instrument according to claim 29, wherein the serration is
configured for engagement with the lock without disposing the lock
in the forward position, said engagement establishing a
pre-determined pivot angle and preventing pivoting of the mobile
portion.
31. An instrument according to claim 18, wherein the handling end
of the instrument comprises a handle configured to allow the
manipulation of the instrument and to facilitate the implantation
of the intersomatic cage between the vertebrae.
32. A method for implanting an intersomatic cage for an
intervertebral fusion graft into the disc space between adjacent
vertebrae of a vertebral column, said disc space comprising an
annulus and a nucleus, said method comprising the steps of:
providing an intersomatic cage for an intervertebral fusion graft
comprising a body generally defining an arc, the body comprising: a
lateral concave surface, a lateral convex surface, a substantially
transverse upper surface, a substantially transverse lower surface,
an end wall at a first longitudinal extremity of the body, the end
wall comprising an end hole configured to receive a retaining end
of a rod of an implantation instrument and oriented substantially
tangential to the arc defined by the body, and an incurvate return
part at a second longitudinal extremity of the body opposite the
end wall, the return part comprising a return hole oriented
substantially tangential to the arc defined by the body and
configured to receive an end portion of an implantation instrument;
providing an instrument comprising: a rod comprising a retaining
end configured for insertion in the end hole, a gripping end for
gripping the intersomatic cage, the gripping end comprising a
support spatula comprising a base and generally defining an arc
complementary to the arc defined by the body, the support spatula
comprising an end portion distal from the base configured for
insertion into the return hole of the intersomatic cage, and a
guide tube in which the rod is slidably disposed and to which the
base of the support spatula is mounted, the guide tube comprising
an opening through which the retaining end of the rod can transit
for insertion in the end hole, and a handling end for manipulating
the instrument; making an incision to access the vertebral column;
incising the annulus and removing the nucleus from the disc space;
inserting the end portion of the spatula into the return hole of
the intersomatic cage; disposing the arc defined by the body
proximal to the arc defined by the spatula; fixing the intersomatic
cage onto the instrument by inserting the retaining end of the rod
into the end hole; disposing the intersomatic cage in the disc
space in an arcing movement; releasing the intersomatic cage from
the instrument by removing the retaining end of the rod from the
end hole; removing the instrument from the disc space; and suturing
the annulus and the skin.
33. A method according to claim 32, wherein the step of disposing
the intersomatic cage in the disc space is preceded or accompanied
by a step of articulating a mobile portion of the instrument to a
selected angle, said step of articulating the mobile portion being
followed by a step of locking the mobile portion at the selected
angle.
34. A method according to claim 32, wherein the step of disposing
the intersomatic cage in the disc space is followed by the steps of
determining the position and orientation of the intersomatic cage
in the disc space by detecting a radio-opaque marker comprised in
the body of the intersomatic cage with x-rays and, if such position
or orientation is improper, adjusting the position or orientation
of the intersomatic cage in the disc space.
35. A method according to claim 32, wherein the steps of inserting
the end portion of the spatula into the return hole of the
intersomatic cage and disposing the arc defined by the body
proximal to the arc defined by the spatula are followed by, and the
step of fixing the intersomatic cage onto the instrument by
inserting the retaining end of the rod into the end hole is
preceded by, a step of engaging a pin of the instrument with a
recess disposed on the end wall of the intersomatic cage.
36. A method according to claim 32, wherein the step of disposing
the intersomatic cage in the disc space is preceded by a step of
distraction of the adjacent vertebrae.
37. An intersomatic cage for an intervertebral fusion graft
comprising: an elongated, curved body with first and second ends; a
lateral concave surface defining a lateral arc congruent with the
lateral concave surface and extending past the first and second
ends of the body, with the lateral concave surface configured to
mate with a complementary support of an insertion instrument; a
lateral convex surface; a substantially transverse upper surface; a
substantially transverse lower surface; and an incurvate return
part located at the second end of the body and protruding from the
body across the lateral arc, with the incurvate return part
disposed on the concave side of the lateral arc and the rest of the
body lying on the convex side of the lateral arc.
Description
CROSS REFERENCE TO RELATED APPLICATIONS:
[0001] This application claims priority under 35 U.S.C. 119 to
French Patent Application No. FR0601315, filed in FRANCE on Feb.
15, 2006, which in incorporated herein by reference for all
purposes.
BACKGROUND:
[0002] This present invention concerns the area of intervertebral
arthrodeses (fusion of two vertebrae) and in particular of
intersomatic cages implanted between two adjacent vertebrae to
allow the insertion and the growth of grafts of osseous tissue (or
of substitute) in the disc space. In fact, after the insertion of
the cage or implant, the intervertebral space is filled with
autologous spongy bone or suitable bone substitutes. The invention
also concerns an instrument for implanting the cage between the
vertebrae, in particular through the transforaminal approach. The
intersomatic cages are designed to be positioned between two
vertebrae, in order to restore and/or maintain the disc space by
replacing the intervertebral disc, and the grafts of osseous tissue
or of substitute are designed to allow fusion between the two
adjacent vertebrae between which they are inserted.
[0003] Various types of intersomatic cage are known from prior art.
Some intersomatic cages known from prior art are machined from
bone, most often cortical bone, so as to fuse with the graft
inserted into the disc space. These cages composed of bone have the
disadvantage to being capable of causing illness in the event of
imperfect sterilisation.
[0004] Different intersomatic cages in solid materials of various
types are also known from prior art. These cages include openings
on their lower surface, their upper surface and on at least one of
their lateral surfaces. One of these cages, in particular known
from patent application WO0187194 (A1) submitted by the present
applicant, has the shape of an open ring and can be used in
combination with another cage of the same type by placing the open
lateral surfaces of the two cages opposite to each other. Whatever
the type of cage in question, spongy bone is compacted inside the
cage, in order to finally achieve an osseous fusion (or
arthrodesis) of the two vertebrae separated by a suitable disc
space. Other cages known from previous designs are of
parallelepiped shape, with the top and the bottom of the cage being
completely open, and the top and bottom openings being designed to
be positioned facing two vertebrae which have to be kept apart from
each other. Openings created in the lateral faces of the
parallelepipeds allow the graft to grow toward the exterior of the
cage and possibly to reach a graft implanted in another cage also
inserted into the disc space. These intersomatic cages have the
disadvantage, firstly, of requiring a relatively large incision in
the annulus (the outer part of the intervertebral disc), secondly,
of requiring a relatively long time before achieving an
arthrodesis, because of the confinement of the graft within a
chamber at the centre of the cage and, thirdly, of having
dimensions that are too large to be implanted through the
transforaminal approach without partial or total ablation of the
articular processes located posterior to the foramen through which
the transforaminal approach runs.
[0005] Also known from previous designs in prior art, in particular
from American patent application US 2005/0038511(A1), are
intersomatic cages of various shapes and dimensions, machined from
bone, and in particular an intersomatic cage of banana (or simple
bracket) shape defining a longitudinal axis of the cage and having
a lower surface and an upper surface, both straight, equipped with
serrations and more or less parallel to the longitudinal axis of
the cage, a concave lateral wall, a convex lateral wall, and two
straight end walls that are more or less perpendicular to the top
and bottom surfaces. One of the end walls of the cage includes a
hole oriented toward the centre of the cage and intended to receive
a rod of an instrument for insertion of the cage between the
vertebrae. This intersomatic cage has the disadvantage of being in
osseous tissue and therefore, as mentioned previously, of being
capable of causing illness in the event of imperfect sterilisation.
This cage may also have the disadvantage of eventually not being
sufficiently solid to reliably take the stresses which will be
applied to it when implanted in the disc space. Furthermore, this
cage has the disadvantage of having a hole oriented toward the
centre of the cage and in particular toward the centre of the
concave surface, the result of which is to make the cage even more
fragile. Moreover, the axis defined by this hole forms an angle, in
relation to an axis parallel to a tangent to one of the concave and
convex surfaces, that is too large to allow to an instrument for
insertion of the cage between the vertebrae to fit onto the cage in
an orientation that is more or less parallel to a tangent to one of
the concave and convex surfaces. Thus, the orientation of the hole
does not conform to the general curvature of the cage obtained by
its convex and concave surfaces and does not allow an effective
thrust to be applied to the cage on its axis of curvature. The
cage, which is made fragile by this hole, is therefore in danger of
breaking when pressure has to be applied at an angle that is too
large in relation to the axis of curvature of the cage, which
therefore proves difficult to implant by the transforaminal
approach. Finally, withdrawal of the instrument inserted into the
hole proves to be difficult due to the unsuitable orientation of
the latter.
[0006] In this context, it is of interest to propose an
intersomatic cage, preferably in a solid and sterile material, that
has a shape and dimensions that make it suitable to be implanted
through the transforaminal approach without an excessively large
lesion of the articular processes, and having resources to fit onto
an instrument for insertion of the cage between the vertebrae, with
an orientation that conforms to the general shape of the cage. It
is also of interest to propose an instrument for implanting the
cage, and which is designed for the shapes and dimensions of the
cage, allowing easy implantation of the cage between the vertebrae.
Also known from prior art are previous designs of instruments for
the implantation of intersomatic cages that have at least one rod
designed to be inserted into a hole in the cage in order to hold
the latter during passage through the foramen. However some of
these instruments known from prior art require an ablation of at
least one part of the articular processes impeding access to the
foramen when the cage and the instrument have excessively large
dimensions. Moreover, the transforaminal approach is relatively
obstructed and is not perfectly straight. It is therefore desirable
that the instrument should have an elbow (a curved or angled
portion) at the end holding the cage. Some instruments known from
prior art have dimensions that are small enough not to necessitate
ablation of the articular processes, and some of these instruments
have an angled portion that allows one to bypass the structure
obstructing access to the disc space, but the rod designed to hold
the cage, as well as the hole of the cage in which this rod is
designed to be inserted, have an orientation that it not very
compatible with the optimal thrust axis allowing insertion of the
cage between the vertebrae and not very compatible with easy
withdrawal of the rod when the cage has been implanted. It is
therefore desirable to propose an instrument whose shape and
dimensions are suitable for insertion using the transforaminal
approach, having an angled portion to bypass the structures
obstructing access to the disc space and having a rod designed to
be inserted into a hole in the cage with an orientation that is
optimal in order to facilitate the implantation of the cage between
the vertebrae, and then withdrawal of the instrument.
SUMMARY:
[0007] This present invention has as its objective to circumvent
some disadvantages of the previous designs by proposing an
intersomatic cage for an intervertebral fusion graft of suitable
shape and of limited dimensions to be implanted through the
transforaminal approach while also having adequate robustness to
effectively maintain a disc space that allows the growth of the
graft.
[0008] This objective is met by a transforaminal intersomatic cage
for an intervertebral fusion graft having a body in the shape of a
circular arc, comprising a lateral concave surface, a lateral
convex surface, a straight upper surface, a straight lower surface
and an end wall with at least one hole, called the end hole,
designed to receive a rod of an instrument for the implantation of
a cage between the vertebrae, wherein:
[0009] the end hole has an orientation that is more or less
tangential to the circular arc described by the body;
[0010] the extremity opposite to the end wall of the body includes
a return part extending the body toward the centre of the circle on
which the circular arc described by the body lies.
[0011] According to another feature, the end wall includes at least
one recess designed to receive at least one pin of a cage
implantation instrument.
[0012] According to another feature, the return part includes at
least one hole, called the return hole, whose orientation is more
or less tangential to a circular arc defined by the concave surface
of the body and designed to receive at least one end portion of a
cage implantation instrument.
[0013] According to another feature, the fitting together of the
end hole, the recess and the return hole with, respectively, the
rod, the pin and the end portion of the cage implantation
instrument ensures a good grip on the cage by the instrument when
one end of the rod is placed in the end hole, and facilitates the
implantation of the cage, with the rod sliding in the instrument so
that it can be removed from the end hole and allow freeing of the
cage and withdrawal of the instrument.
[0014] According to another feature, at least one of the upper and
lower surfaces of the body is endowed with serrations that oppose
the movement of the cage in relation to the adjacent vertebrae
between which it is implanted.
[0015] According to another feature, the return part includes upper
and lower surfaces extending, respectively, the upper and lower
surfaces of the body, with at least one of these upper and lower
surfaces of the return part also being equipped with serrations
that oppose the movement of the cage.
[0016] According to another feature, the return part includes upper
and lower surfaces extending, respectively, the upper and lower
surfaces of the body, with at least one of these upper and lower
surfaces of the return part having at least one chamfer
facilitating the insertion of the cage into the disc space.
[0017] According to another feature, the extremities of the
circular arc described by the body define a longitudinal axis of
the cage, with at least one part of the serrations being oriented
parallel to this longitudinal axis of the cage.
[0018] According to another feature, the extremities of the
circular arc described by the body define a longitudinal axis of
the cage, with at least one part of the serrations being oriented
perpendicularly to this longitudinal axis of the cage.
[0019] According to another feature, the extremities of the
circular arc described by the body define a longitudinal axis of
the cage, with at least one part of the serration having the shape
of chevrons centred on an axis perpendicular to this longitudinal
axis of the cage.
[0020] According to another feature, the extremities of the
circular arc described by the body define a longitudinal axis of
the cage, with at least one part of the serrations describing
concentric circular arcs each having, together with the circular
arc described by the body, an axial symmetry whose axis of symmetry
is parallel to this longitudinal axis of the cage.
[0021] According to another feature, at least one part of the
serrations are oriented parallel to radii defined by the circle on
which the circular arc described by the body lies.
[0022] According to another feature, the serrations present on a
given surface of the cage have the same orientation.
[0023] According to another feature, the serrations present on a
given surface of the cage do not have the same orientation.
[0024] According to another feature, the serrations present on two
opposite surfaces of the cage have the same orientation.
[0025] According to another feature, the serrations present on two
opposite surfaces of the cage do not have the same orientation.
[0026] According to another feature, the body includes at least one
radio-opaque marker allowing the cage to be viewed by x-ray.
[0027] Another objective of this present invention is to propose an
instrument for implanting an intersomatic cage between the
vertebrae, facilitating access to the disc space and allowing a
good grip to be obtained on the cage.
[0028] This objective is met by an instrument for the implantation
of a transforaminal intersomatic cage for an intervertebral fusion
graft having a body in the shape of a circular arc, comprising a
lateral concave surface, a lateral convex surface, a straight upper
surface, a straight lower surface, and an end wall having at least
one hole, called the end hole, designed to receive one end of a rod
of the instrument, with the end hole having an orientation that is
more or less tangential to the circular arc described by the body,
wherein said instrument comprises an extremity for gripping the
cage, called the gripping end, and an extremity for manipulating
the instrument, called the handling end, wherein:
[0029] the gripping end comprises at least one tube, called the
guide tube onto one end of which is mounted, on one edge, a
spatula, called the support spatula, in a circular arc, designed to
at least partially fit onto the circular arc described by the body
of the cage,
[0030] the guide tube comprising, at the base of the support
spatula, an opening through which one end of the rod, mounted to
slide in the guide tube, has a shape and dimensions making it
suitable to be inserted into the end hole of the cage, so as to
allow the cage to be gripped.
[0031] According to another feature, the rod extends up to the
vicinity of the handling end of the instrument.
[0032] According to another feature, the rod includes at least one
button projecting through a groove on at least one edge of the
instrument, where this button allows the rod to be slid and its
position to be adjusted in relation to the opening present at the
end of the guide tube holding the support spatula.
[0033] According to another feature, the guide tube includes, at
the end on which the support spatula is mounted but on the opposite
edge, at least one pin whose shape and dimensions are suitable to
fit onto at least one recess present on the end wall of the
cage.
[0034] According to another feature, the support spatula includes,
at the end opposite to the guide tube, at least one end portion
whose shape and dimensions make it suitable to be inserted into at
least one hole, called the return hole, present on a return part
extending the body of the cage toward the centre of the circle on
which the circular arc defined by this body lies, at the end
opposite to the end wall of the body, this return hole having an
orientation that is more or less tangential to a circular arc
defined by the concave surface of the body.
[0035] According to another feature, the fitting together of the
rod, the pin and the end portion of the cage implantation
instrument with, respectively, the end hole, the recess and the
return hole of the cage, ensures a good grip on the cage by the
instrument when one end of the rod is placed in the end hole, and
facilitates the implantation of the cage, with the rod to slide in
the guide tube allowing withdrawal of the rod from the hole and
freeing of the cage, and facilitating the withdrawal of the
instrument once the cage has been implanted.
[0036] According to another feature, the guide tube includes, at
the end opposite to that holding the support spatula, a mobile
portion that pivots in relation to a tube, called the aiming tube,
extending up close to the handling end of the instrument, said
mobile portion pivoting in at least one direction that is more or
less parallel to the orientation of the circular arc defined by the
support spatula.
[0037] According to another feature, the mobile portion and the
aiming tube form a ball and socket connection, one of them having
one end in the form of a sphere and the other having a hollow end
forming a spherical recess whose shape and dimensions are
complementary to those of this sphere.
[0038] According to another feature, at least the edge of the
spherical recess located on the same side of the instrument as the
support spatula, in the ball and socket connection formed by the
mobile portion and the aiming tube, encompasses the sphere to a
lesser extent than the other edges of this recess, so as to allow
pivoting at least in a direction that is more or less parallel to
the orientation of the circular arc defined by the support
spatula.
[0039] According to another feature, the rod is flexible and
traverses the ball and socket connection at its centre, the sphere
having a channel at its centre to allow the rod to slide, where
this channel has a hollowed portion at least on its edge located on
the same side of the instrument as the support spatula, so as to
allow the rod to slide through the ball and socket connection even
when the instrument is in its angled position due to pivoting of
the ball and socket connection in a direction that is more or less
parallel to the orientation of the circular arc defined by the
support spatula.
[0040] According to another feature, a locking tube is screwed onto
the aiming tube and includes a locking ring that allows the locking
tube to be screwed in, so that screwing in and unscrewing results
in forward and reverse motion of the locking tube in relation to
the aiming tube, the forward motion of the locking tube resulting
in bringing the locking tube into contact with the mobile portion
and, as a consequence, preventing the pivoting of the mobile
portion of the guide tube in relation to the aiming tube, to any
angle between the guide tube and the aiming tube.
[0041] According to another feature, the mobile portion that pivots
in relation to the aiming tube includes at least one serration
which is used to obtain a given angle between the guide tube and
the aiming tube, where the maximum angle in the presence of this
serration is greater than in its absence because of the presence of
the locking tube.
[0042] According to another feature, at least one edge of one end
of the locking tube locks into the serration, when the guide tube
forms a given angle with the aiming tube, so as to prevent pivoting
and to maintain the instrument in at least one position, until it
is totally immobilised by screwing in the locking tube.
[0043] According to another feature, the handling end of the
instrument is fitted with a handle allowing the manipulation of the
instrument and facilitating the implantation of the cage between
the vertebrae, by allowing effective thrust to be applied to the
instrument.
[0044] Another objective of the preset invention is to propose a
method for implanting a transforaminal intersomatic cage according
to the invention into the disc space with an instrument according
to the invention.
[0045] This objective is reached by a method for implanting a
transforaminal intersomatic cage for an intervertebral fusion graft
having a body in the shape of a circular arc, comprising a lateral
concave surface, a lateral convex surface, a straight upper
surface, a straight lower surface and an end wall with at least one
hole, called the end hole, having an orientation that is more or
less tangential to the circular arc described by the body and
designed to receive a rod of an instrument for the implantation of
a cage between the vertebrae, the extremity opposite to the end
wall of the body including a return part extending the body toward
the centre of the circle on which the circular arc described by the
body lies, said return part including at least one hole, called the
return hole, whose orientation is more or less tangential to a
circular arc defined by the concave surface of the body and
designed to receive at least one end portion of a cage implantation
instrument, said method comprising a step of insertion of the cage
in the disc space with an instrument comprising an extremity for
gripping the cage, called the gripping end, and an extremity for
manipulating the instrument, called the handling end, said gripping
end comprising at least one tube, called the guide tube onto one
end of which is mounted, on one edge, a spatula, called the support
spatula, in a circular arc, designed to at least partially fit onto
the circular arc described by the body of the cage, said spatula
including, at the end opposite to the guide tube, at least one end
portion whose shape and dimensions make it suitable to be inserted
into the return hole and said guide tube comprising, at the base of
the support spatula, an opening through which one end of the rod,
mounted to slide in the guide tube, has a shape and dimensions
making it suitable to be inserted into the end hole of the cage,
said method comprising the following steps:
[0046] incising the skin and muscles laterally to the vertebral
column,
[0047] incising the annulus, removing the nucleus and clearing the
disc space,
[0048] inserting the end portion of the spatula into the return
hole of the cage, moving the circular arc of the body in relation
to the spatula and locking the cage onto the instrument by sliding
the rod until it enters into the end hole,
[0049] impacting the cage in the disc space, in a circular
movement,
[0050] releasing the cage from the instrument by sliding the rod
until it exits from the end hole and removing the instrument,
[0051] suturing the annulus and the skin.
[0052] According to another feature, the step of impacting the cage
in the disc space is preceded or accompanied by a step of
articulating a mobile portion at a distal end of the instrument to
find the most appropriate angle for engagement of the cage in the
disc space, said step of articulating the mobile portion being
followed by a step of locking the mobile portion at the desired
angle by screwing a locking tube preventing the pivoting of the
mobile portion.
[0053] According to another feature, the step of impacting the cage
in the disc space is followed by a step of checking the position
and orientation of the cage in the disc space by applying x-ray
detecting at least one radio-opaque marker present in the body of
the cage, said step of checking being, if necessary, followed by a
step of adjusting the position and/or orientation of the cage in
the disc space, prior to release from the instrument.
[0054] According to another feature, the step of inserting the end
portion of the spatula into the return hole of the cage and moving
the circular arc of the body in relation to the spatula is
followed, when the guide tube of the instrument includes, at the
end on which the support spatula is mounted but on the opposite
edge, a pin whose shape and dimensions are suitable to fit onto at
least one recess present on the end wall of the cage, by a step of
locking said pin into said recess, prior to locking the cage onto
the instrument by sliding the rod until it enters into the end
hole.
[0055] According to another feature, the step of impacting the cage
in the disc space is preceded by a step of distraction of the
adjacent vertebrae by tools of known types, in order to facilitate
the access to the disc space
BRIEF DESCRIPTION OF THE DRAWINGS:
[0056] Other features and advantages of this present invention will
appear more clearly on reading the description that follows,
provided with reference to the appended drawings, in which:
[0057] FIGS. 1A, 1B, 1C and 1D are views in perspective of the
intersomatic cage according to various embodiments of the
invention;
[0058] FIGS. 2A and 2C are views in profile of one embodiment of
the instrument for implanting intersomatic cage between the
vertebrae, with the gripping end of the instrument in position,
respectively straight and angled, with FIGS. 2B and 2D showing the
detail of the portions indicated by circles 2B and 2D respectively
in FIGS. 2A and 2C respectively;
[0059] FIG. 3A provides a top view of one embodiment of the
instrument for implanting an intersomatic cage with a plane section
3B-3B, with FIG. 3B showing a view in section according to axis
3B-3B of this embodiment of the insertion instrument, and FIGS. 3C
and 3D showing the detail of the portions indicated, respectively,
by circles 3C and 3D in FIG. 3B;
[0060] FIG. 4A provides a view in profile of one embodiment of the
instrument for implanting an intersomatic cage with a method for
insertion of the intersomatic cage held at the gripping end of the
instrument, with FIG. 4B showing the detail of the portion
indicated by circle 4B in FIG. 4A, and FIG. 4C showing a top view
of this embodiment of the instrument holding the intersomatic cage,
with a plane section 4D-4D, where FIG. 4D provides a view in
section according to axis 4D-4D of this embodiment, and FIG. 4E
shows the detail of the portion indicated by circle 4E in FIG.
4D.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0061] This present invention concerns a transforaminal
intersomatic cage for an intervertebral fusion graft. This cage is
used to maintain a disc space that is sufficient to allow a graft
to be inserted into the disc space in order to grow and to allow an
osseous fusion (arthrodesis) of the adjacent vertebrae. This cage
is called transforaminal since it is particularly suitable to be
implanted through the transforaminal approach, although it can also
be implanted by any approach to suit the convenience of the surgeon
responsible for the implantation. In a manner which is already
known, this intersomatic cage has a body (1) in the shape of a
circular arc having a lateral concave surface (10), a lateral
convex surface (11), a straight upper surface (12), and a straight
lower surface (13). The body (1) therefore has more or less the
shape of a banana or simple bracket, and therefore does indeed
describe a circular arc.
[0062] This circular arc shape of the cage according to various
embodiments of the invention is particularly well-matched to the
shape of the edges of the vertebral plates, which allows the cage
to be positioned in the vicinity of the periphery of the vertebral
plates, that is to say on their most solid portion. A cage
according to various embodiments the invention will therefore be
implanted at the level of the anterior peripheral portion of the
vertebral plates, for example. This positioning of the cage close
to the edges of the vertebral plates also enables to obtain a large
initial surface for an osseous graft or a substitute. At one of the
extremities of the body (1), the cage includes an end wall (14)
having at least one hole (30), called the end hole, designed to
receive a rod (53) of an instrument (5) for implantation of the
cage between the vertebrae.
[0063] In a particularly advantageous embodiment of the cage
according to the invention, the end hole (30) has an orientation
that is more or less tangential to the circular arc described by
the body (1). This orientation of the end hole (30) tangentially to
the circular arc described by the body (1) facilitates the
thrusting of the cage by the cage implantation instrument (5) and
facilitates the insertion and withdrawal of the rod (53) of this
instrument (5), respectively, into and out of the end hole (30).
Moreover, this end wall (14) includes at least one recess (31)
designed to receive at least one pin (54) of a cage implantation
instrument (5). This recess (31) is used to provide an additional
surface for the gripping of the cage by the instrument. It can
consist of a simple shoulder or a recess of more complex shape such
as, for example, a recess with a groove in which a serration of the
pin (54) (thus having the shape of a spur, for example) of the
instrument (5) can be locked.
[0064] In a particularly advantageous embodiment of the cage
according to the invention, the extremity opposite to the end wall
(14) of the body (1) includes a return part (15) extending the body
(1) toward the centre of the circle on which the circular arc
described by the body (1) lies. This return part provides better
stability of the intersomatic cage between the vertebrae without
increasing its dimensions excessively. This return part is used to
prevent the intersomatic cage from tilting to one of its sides
under the effect of the stresses to which it is subjected when
implanted between two vertebrae of a patient. Moreover, this return
part (15) includes at least one hole (32), called the return hole,
whose orientation is more or less tangential to a circular arc
defined by the concave surface (10) of the body (1) and designed to
receive at least one end portion (55) of a cage implantation
instrument (5). Thus, the instrument (5) can include a spatula (56)
having a shape complementary to that of the circular arc described
by the body. This spatula (56) thus hugs the shape of the cage by
fitting its body (1). At one end of the spatula (56), an end
portion (55) can be designed for insertion into this return hole
(32). The fitting together of the end hole (30), the recess (31)
and the return hole (32) with the rod (53), the pin (54) and the
end portion (55) of the cage implantation instrument (5)
respectively, ensures a good grip on the cage by the instrument (5)
when one end of the rod (53) is placed in the end hole (30). This
complete gripping of the cage up to the most distal end facilitates
the implantation of the cage by providing good stability of the
cage at the end of the instrument (5). This good stability is also
particularly important in the case of implantation through the
transforaminal approach. The rod (53) is designed to slide in the
instrument (5) so that it can be withdrawn from the end hole (30)
and to allow freeing of the cage and withdrawal of the instrument
(5).
[0065] In a manner which is already known, at least one of the
upper and lower surfaces of the body (1) is equipped with
serrations (20) that oppose the movement of the cage in relation to
the adjacent vertebrae between which it is implanted. The invention
provides for different possible orientations of the serrations
(20). In an advantageous manner, in one embodiment of the
invention, the serrations (20) present on two opposite surfaces of
the cage may not have the same orientation, so as to oppose the
movement of the cage in different directions for each of the faces,
as can be seen particularly in FIGS. 1A to 1C. In another
embodiment, the serrations (20) present on two opposite surfaces of
the cage will have the same orientation, as can be seen
particularly in FIG. 1D. Likewise, serrations (20) present on one
surface of the cage can have an orientation that is different from
other serrations located on the same surface. Conversely, all the
serrations (20) present on a given surface of the cage can have the
same orientation. Depending on the embodiment, the intersomatic
cage can therefore include any combination of these orientations on
all or part of either of its surfaces. The extremities of the
circular arc described by the body (1) define a longitudinal axis
of the cage. The cage has larger dimensions on this longitudinal
axis than on the axis perpendicular to it. This longitudinal axis
will allow the different possible orientations of the serrations to
be defined. Thus in one embodiment, at least one part of the
serrations (20) can be oriented parallel, as can be seen
particularly in FIG. 1C, or perpendicular to this longitudinal axis
of the cage. In another embodiment, they can be oriented so as to
form an angle of between 0 and 90 degrees in relation to this
longitudinal axis of the cage. In another embodiment, at least one
part of the serrations (20) can describe chevrons that are centred
in relation to an axis perpendicular to this longitudinal axis, as
can be seen particularly in FIG. 1A. In another embodiment, at
least one part of the serrations (20) can describe concentric
circular arcs, each with, in relation to the circular arc described
by the body (1), an axial symmetry whose axis of symmetry is
parallel to this longitudinal axis of the cage. In another
embodiment, at least one part of the serrations (20) will be
oriented parallel to radii defined by the circle on which the
circular arc described by the body lies (1), as can be seen
particularly in FIGS. 1B and 1D.
[0066] Furthermore, the return part (15) includes upper and lower
surfaces extending the upper and lower surfaces respectively of the
body (1). In one embodiment, at least one of these upper and lower
surfaces of the return part (15) can also be equipped with
serrations (20) that oppose the movement of the cage. In another
embodiment, at least one of these upper and lower surfaces of the
return part (15) can include at least one chamfer (16) facilitating
the insertion of the cage in the disc space, as can be seen
particularly in FIG. 1A.
[0067] This present invention also concerns an instrument (5) for
the implantation of an intersomatic cage between the vertebrae.
This instrument according to the invention is particularly suitable
for implantation, through the transforaminal approach, of an
intersomatic cage for an intervertebral fusion graft, although it
could naturally be used for any approach that is convenient for the
surgeon responsible for the implantation. The instrument (5) is
designed to be particularly suitable for use in combination with
the intersomatic cage described previously. The instrument (5)
according to an embodiment of the invention includes an extremity
for gripping the cage allowing the cage to be held at the end of
the instrument and called the gripping end. The extremity of the
instrument opposite its gripping end allows the manipulation of the
instrument by the surgeon and is called the handling end. The
gripping end of the instrument (5) includes at least one tube (52),
called the guide tube. At the extremity of this guide tube (52), on
one edge of the latter, is mounted a spatula (56), called the
support spatula. This spatula (56) has the shape of a circular arc,
designed to at least partially fit onto the circular arc described
by the body (1) of the cage. By hugging the shape of the body (1),
this spatula provides the cage with solidity. The spatula will
therefore protect the cage in particular against impact, to which
it is sometimes less resistant than to pressures. At the base of
the support spatula (56), the guide tube (52) includes an opening
through which one end of the rod (53) passes to fit into the end
hole (30) of the cage. This rod (53) is mounted to slide in the
guide tube (52) and has a shape and dimensions that make it
suitable to be inserted into the end hole (30) of the cage, so as
to allow the cage to be gripped. In one embodiment, this rod (53)
extends up to the vicinity of the handling end of the instrument
(5). The rod (53) includes at least one button (61) projecting
through a groove (610) on at least one edge of the instrument (5),
this button (61) allowing the rod to be slid (53) and its position
to be adjusted in relation to the opening present at the end of the
guide tube (52) holding the support spatula (56). This button will
preferably be located at the extremity of the rod (53) and,
according to the embodiment, can therefore be located close to the
handling end of the instrument (5) or anywhere on the instrument,
although it would obviously be more practical, in principle, that
it should be close to the handling end.
[0068] In one embodiment, the guide tube (52), at the end on which
the support spatula is mounted (56) but on the opposite edge,
includes at least one pin (54) whose shape and dimensions are
suitable to fit onto at least one recess (31) present on the end
wall (14) of the cage. This embodiment is particularly suitable for
the one of the embodiments of the cage presented above and improves
the quality of the grip on the cage by the instrument (5).
[0069] In one embodiment, the support spatula (56), at the end
opposite to the guide tube (52), includes at least one end portion
(55) whose shape and dimensions make it suitable to be inserted
into at least one hole (32), called the return hole, present on a
return part (15) of the cage. This embodiment is particularly
suitable for the one of the embodiments of the cage in which a
return part (15) extends the body (1) toward the centre of the
circle on which the circular arc described by the body (1) lies.
Since this return hole (32) has an orientation that is more or less
tangential to a circular arc defined by the concave surface (10) of
the body (1), the end portion (55) at the end of the spatula (56)
in a circular arc will therefore have a shape that is particularly
suitable to fit into the return hole (32). In one embodiment that
combines the resources for fitting together the instrument and the
cage, described above, with the fitting together of the rod (53),
the pin (54) and the end portion (55) of the cage implantation
instrument (5) to the end hole (30), the recess (31) and the return
hole (32) respectively of the cage, ensures a good grip on the cage
by the instrument (5) when one end of the rod (53) is placed in the
end hole (30), and facilitates the implantation of the cage.
[0070] In a particularly advantageous embodiment and suitable for
the transforaminal approach, the guide tube (52), at the end
opposite to that holding the support spatula (56), includes a
mobile portion (57) that pivots in relation to a tube (59), called
the aiming tube, extending up close to the handling end of the
instrument (5). This mobile portion (57) pivots in at least one
direction that is more or less parallel to the orientation of the
circular arc defined by the support spatula (56). As can be seen
particularly in FIG. 3C, the mobile portion (57) and the aiming
tube (59) together can form a ball and socket connection (or swivel
link), one of them having one end in the form of a ball or sphere
(592) and the other having a hollow end forming a socket, called
spherical recess (571), whose shape and dimensions are
complementary to those of this sphere. In the embodiment
illustrated in FIG. 3C, one end of the aiming tube (59) has a shape
of sphere (592) and the corresponding end of the guide tube (52)
forms a spherical recess. In one embodiment of the invention, at
least the edge (575) of the spherical recess (571) located on the
same side of the instrument (5) as the support spatula (56), in the
ball and socket connection formed by the mobile portion (57) and
the aiming tube (59), encompasses the sphere to a lesser extent
than the other edges (576) of this recess (571), so as to allow
pivoting at least in a direction that is more or less parallel to
the orientation of the circular arc defined by the support spatula
(56).
[0071] In one embodiment, the rod (53) is flexible, and traverses
the ball and socket connection at its centre. The sphere (592) then
has a channel at its centre to allow the rod to slide (53). This
channel will be hollowed out at least on its edge located on the
same side of the instrument (5) as the support spatula (56). Thus,
the channel will include a hollowed out portion (593) allowing the
rod (53) to slide through the ball and socket connection even when
the instrument (5) is in its angled position due to pivoting of the
ball and socket connection, as illustrated in FIGS. 2C and 2D.
[0072] In one embodiment, a locking tube (58) is screwed onto the
aiming tube (59) and includes a locking ring (60) that allows the
locking tube to be screwed in (58). Screwing-in and unscrewing
allows the forward and backward motion of the locking tube (58) in
relation to the aiming tube (59). The forward motion of the locking
tube (58) results naturally in bringing the locking tube (58) into
contact with the mobile portion (57) and, as a consequence,
prevents the pivoting of the mobile portion (57). Thus, the guide
tube (52) can be locked in relation to the aiming tube (59), at any
angle between the guide tube (52) and the aiming tube (59). The
mobile portion (57) that pivots in relation to the aiming tube (59)
can also, in one embodiment, include at least one serration (574),
particularly visible in FIG. 3C. The presence of this serration
(574) allows pivoting of the mobile portion (57) through a larger
amplitude than if the mobile portion entered directly into contact
with the locking tube (58). This serration (574) allows to obtain a
particular angle formed by the angled portion between the support
tube (52) and the aiming tube (59). Moreover, in one embodiment,
this serration (574) can be designed so that when the guide tube
(52) forms a given angle with the aiming tube (59), one edge of one
end of the locking tube (58) locks into this serration (574), as
illustrated in FIGS. 2A to 2D. This serration (574) is therefore
used to stop the pivoting and to maintain the instrument in at
least one position until it is totally immobilised by screwing-in
of the locking tube (58).
[0073] In a manner which is already known, the handling end of the
instrument (5) can naturally be fitted with a handle (62) allowing
the manipulation of the instrument (5) and facilitating the
implantation of the cage between the vertebrae by allowing
effective thrust to be applied to the instrument (5).
[0074] As mentioned previously, the intersomatic cage and the
instrument according to this present invention are particularly
suitable for implantation of the cage between two adjacent
vertebrae using the transforaminal approach. This implantation can
be performed as described below, although other procedural variants
can naturally exist, and the surgeon can naturally adapt the
technique described here at his convenience, in accordance with any
changes in the techniques employed conventionally for example. In
particular, this present invention can be used in combination with
osseous anchor implants, connected together by immobilising bars,
allowing the movement of the two adjacent vertebrae, between which
the cage is designed to be inserted, to be eliminated or limited.
These osseous anchor implants can consist, for example, of those
described in the international patent applications submitted by
this present applicant and published under the numbers
WO02/080788(A1), WO03/049629(A1) and WO2005/020829(A1) or by any
other type of resources for immobilisation of the adjacent
vertebrae. The procedure relating to the joining of the adjacent
vertebrae is specific to the resources used to immobilise the
adjacent vertebrae and therefore need not be described here.
[0075] Only the procedure used during an implantation through the
transforaminal approach will be detailed here, the implantation by
other approaches being relatively similar but easier, in particular
because of the fact that the transforaminal approach needs to
bypass the articular processes. The procedure for implantation
through the transforaminal approach begins naturally by at least
one incision laterally to the axis of the vertebral column.
Preferably, two intermuscular incisions will be made, along a path
that is well known to the professional surgeon for example, as
described by Dr Wiltse. According to the size of the cage chosen
and/or according to the space between the two vertebrae, a
resection, at least partial, of the articular processes can be
effected in order to improve access to the foramen and to the disc
space. These articular processes will then preferably be resected
laterally, on the side for insertion of the cage. If an
intra-articular graft is desired, an opening and an avivement
(withdrawal of the cartilage) of the articular processes, at least
on one side but possibly on both sides, will allow the insertion of
at least one intra-articular graft. The insertion of the osseous
anchor implants designed to immobilise the two adjacent vertebrae
can be effected at this stage of the procedure. These osseous
anchor implants screwed into each of the adjacent vertebrae and
connected together by a bar, here allow a first posterior
distraction in order to facilitate access to the disc space. A tool
of known type such as a nerve root retractor (or root spreader) can
be used to protect the roots of the vertebrae. A lateral incision
in the external layer of the annulus, between the transverse
articular processes for example, will provide access to the disc
space. In a manner which is already familiar, the formation of an
open flap, held by suspension ties for example, will facilitate the
following operations. Then the surgeon will proceed to the complete
removal of the nucleus and of the internal layers of the annulus.
Different tools of known types, such as an angled disc clamp,
curettes and rasps (straight and angled) will be used at this stage
to prepare the disc space and withdraw the cartilage from the
vertebral plates without damaging or weakening it.
[0076] At this stage of the procedure, the surgeon will have
cleared access to the disc space. The osseous anchor implants will
allow the surgeon to spread the vertebrae so as to facilitate
insertion of the cage. For example, the surgeon will use osseous
anchor implants screwed into the vertebrae and connected together
by a bar parallel to the axis of the vertebral column. The osseous
anchor implants generally include screws driven into the vertebrae
and defining a longitudinal securing axis. At this stage, these
longitudinal axes of the osseous anchor implants are not parallel
to each other but cross in front of the vertebral column. Together
with the axis of the bar, these axes form an inverted capital A.
The surgeon will then adjust the spread of the osseous anchor
implants. To this end, the surgeon can position spreader tubes on
the heads of the osseous anchor implants in order to spread these
as much as possible, and will then screw in the head of these
osseous anchor resources on the bar to fix their position along the
bar parallel to the axis of the vertebral column. The osseous
anchor implants thus implanted and held securely on the bar will
allow an anterior distraction to be performed. The surgeon applies
pressure to the spreader tubes so as to move them toward each
other, which tends to open the inverted capital A at its base, so
that it becomes a capital H. This operation can possibly be
repeated several times by unscrewing the heads of the osseous
anchor implants from the bar and separating the spreader tubes to
spread the heads and then screwing in the heads of the implants and
drawing together the spreader tubes to spread the feet of the
capital H, thus opening the disc at the front. This anterior
opening of the disc space can be accompanied by an adjustment of
the lordosis.
[0077] The surgeon will then proceed to the choice of the cage to
be implanted, using trial cages with the same dimensions as the
cages designed to be implanted. A trial cage is placed on the
instrument (5) and is then impacted into the disc space. Impaction
should be effected without excessive force in order not to weaken
(damage) the vertebral plates. The trial cage is removed using a
tool of known type such as an extraction masselotte (or extractor
or removal masselotte or bobweight), and this operation can be
repeated until a cage of satisfactory size has been found.
[0078] The definitive cage can then be placed on the implantation
instrument (5) by inserting the end portion (55) of the spatula
(56) into the return hole (32) of the cage and moving the circular
arc of the body (1) in relation to the spatula (56) until the pin
(54) locks into the recess (31) of the end wall (14). The cage is
then locked onto the instrument (5) by means of the sliding rod
(53) which enters into the end hole (30). Articulation of the
instrument at its distal part by means of the mobile portion (57)
allows the most appropriate angle to be found for engagement of the
cage in the intersomatic space. The angle can be locked by the
screwing in the locking tube (58) using the threaded ring (60) for
example by means of a tool of known type such as a pin wrench. The
cage thus held on the instrument and oriented in an optimal manner
can then be impacted between the vertebrae. The cage will
preferably be impacted as anteriorly as possible, in a circular
movement. In order to optimise the positioning of the cage, the
angle of the articulation formed by the mobile part (57) can be
adjusted during impaction, taking care to correctly lock this angle
by means of the locking ring (60). The position and the orientation
of the cage in the intersomatic disc space can then be verified by
means of an x-ray appliance of known type, such as a brightness
amplifier for example. In fact, in one embodiment the cage includes
at least one radio-opaque marker which will be detected by the
brightness amplifier. The surgeon can then adjust the positioning
of the cage according to the position and the orientation of the
marker or markers. When the cage has been correctly implanted, it
will be released from the instrument (5) by moving the sliding rod
(53) in the direction of the handling end. The surgeon then only
has to position the osseous graft(s) or substitute(s) between the
cage (preferably placed at the level of the anterior edges of the
vertebral plates) and the medulary cavity. To this end, the surgeon
will use a tool of known type, such as a spatula for example. The
flap formed in the external layer of the annulus can then be
re-closed and sutured, so as to maintain the graft in place. A
graft, of the posterolateral type for example, can be effected at
this stage in order to optimise the joining together of the
vertebrae. Graft will be then placed on the transverse articular
process for example. A redon drain can possibly then be put in
place, and a subcutaneous suturing followed by a cutaneous suturing
of the incisions will allow the surgical procedure to be
finalised.
[0079] It should be obvious to people well versed in these
techniques that this present invention allows embodiments in many
other specific forms without the moving outside the scope of the
invention as claimed. As a consequence, the present embodiments
should be considered as illustrations only, but can be modified
within the domain defined by the reach of the attached claims, and
the invention must not be limited to the details given above.
* * * * *