U.S. patent application number 14/206508 was filed with the patent office on 2014-07-10 for expandable spinal rods and methods of use.
This patent application is currently assigned to WARSAW ORTHOPEDIC, INC.. The applicant listed for this patent is WARSAW ORTHOPEDIC, INC.. Invention is credited to Randall N. Allard, Kent M. Anderson, Aurelien Bruneau, Eric C. Lange.
Application Number | 20140194932 14/206508 |
Document ID | / |
Family ID | 37913677 |
Filed Date | 2014-07-10 |
United States Patent
Application |
20140194932 |
Kind Code |
A1 |
Bruneau; Aurelien ; et
al. |
July 10, 2014 |
EXPANDABLE SPINAL RODS AND METHODS OF USE
Abstract
A spinal rod having first and second end members. The end
members may be flexible or rigid. An expandable intermediate
section is positioned between the first and second end members. The
intermediate section may be axially expandable upon the
introduction of a substance into a port that may be located in
either of the first and second end members or the intermediate
section. The intermediate section may be expandable between a first
size, where the first and second end members are spaced a first
distance apart, and a second enlarged size, where the first and
second end members are spaced a second greater distance apart.
Inventors: |
Bruneau; Aurelien;
(Jacksonville, FL) ; Lange; Eric C.; (Pleasanton,
CA) ; Allard; Randall N.; (Issaquah, WA) ;
Anderson; Kent M.; (Mountain View, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WARSAW ORTHOPEDIC, INC. |
Warsaw |
IN |
US |
|
|
Assignee: |
WARSAW ORTHOPEDIC, INC.
Warsaw
IN
|
Family ID: |
37913677 |
Appl. No.: |
14/206508 |
Filed: |
March 12, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12836721 |
Jul 15, 2010 |
8728125 |
|
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14206508 |
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|
11343713 |
Jan 31, 2006 |
7776075 |
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12836721 |
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Current U.S.
Class: |
606/258 |
Current CPC
Class: |
A61B 2017/00557
20130101; A61B 17/7004 20130101; A61B 17/7008 20130101; A61B
2017/00535 20130101; A61B 17/7005 20130101; A61B 17/7014 20130101;
A61B 17/7052 20130101 |
Class at
Publication: |
606/258 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Claims
1-49. (canceled)
50. A spinal rod system comprising: first and second anchors having
a transverse member for receiving a first end member and a second
end member, the first end member having an axial end portion seated
into the first anchor such that the first end member is prevented
from moving beyond the first anchor; the second end member having
an axial end portion seated into the second anchor such that the
second end member is prevented from moving beyond the second
anchor; and an intermediate section connected to the first and
second end members; and a port operatively connected to the
intermediate section; the intermediate section being axially
expandable upon the introduction of a substance into the port, the
intermediate section being rigid before the introduction of the
substance into the port, the intermediate section being expandable
between a first size to space the first and second end members a
first distance apart and a second enlarged size to space the first
and second end members a second greater distance apart.
51. The spinal rod system of claim 50, wherein the intermediate
section is configured to apply a distraction force to vertebral
members after the axial end portion of the first end member is
fixed into the first anchor and the axial end portion of the second
end member is fixed into the second anchor upon introduction of the
substance into the port.
52. The spinal rod system of claim 50, wherein the first end member
engages the first anchor and the second end member engages the
second anchor such that the first and second anchors are disposed
to penetrate bone in a transverse orientation in relation to the
first and second end members.
53. The spinal rod system of claim 50, wherein the intermediate
section is rigid after the introduction of the substance into the
port.
54. The spinal rod system of claim 50, wherein the intermediate
section is flexible after the introduction of the substance into
the port.
55. The spinal rod system of claim 50, wherein the port is axially
disposed in one of the end members.
56. The spinal rod of claim 50, wherein the port is radially
disposed in one of the end members.
57. The spinal rod of claim 50, wherein the port is disposed in the
intermediate section.
58. The spinal rod of claim 50 wherein each of the first and second
end members have a width that is substantially equal to that of the
intermediate section when the intermediate section is expanded to
the second enlarged size.
59. The spinal rod of claim 50 wherein the intermediate section
comprises multiple concentric columns having widths that permit the
columns to collapse within one another when the intermediate
section is at the first size, the concentric columns extending
axially relative to one another when the intermediate section is
expanded to the second enlarged size.
60. The spinal rod of claim 50 further comprising a third member
and a second intermediate section, the third member having a
clamping portion to be operatively connected with a vertebral
member, and the third member positioned between the intermediate
section and the second intermediate section.
61. The spinal rod of claim 50 wherein the intermediate section is
a chamber disposed in at least one of the two end members.
62. The spinal rod of claim 50 wherein the first end member has a
perforated protrusion extending inwardly.
63. The spinal rod of claim 62 wherein the second end member has a
perforated protrusion extending inwardly.
64. A spinal rod system comprising: first and second anchors having
a transverse member for receiving a first end member and a second
end member, the first end member having an axial end portion seated
into the first anchor such that the first end member is prevented
from moving beyond the first anchor, the first end member having a
perforated protrusion extending inward; the second end member
having an axial end portion seated into the second anchor such that
the second end member is prevented from moving beyond the second
anchor, the second end member having a perforated protrusion
extending inward; and an intermediate section connected to the
first and second end members; and a port operatively connected to
the intermediate section; the intermediate section being axially
expandable upon the introduction of a substance into the port, the
intermediate section being rigid before the introduction of the
substance into the port, the intermediate section being expandable
between a first size to space the first and second end members a
first distance apart and a second enlarged size to space the first
and second end members a second greater distance apart, wherein the
intermediate section is configured to apply a distraction force to
vertebral members after the axial end portion of the first end
member is fixed into the first anchor and the axial end portion of
the second end member is fixed into the second anchor upon
introduction of the substance into the port, wherein the first end
member engages the first anchor and the second end member engages
the second anchor such that the first and second anchors are
disposed to penetrate bone in a transverse orientation in relation
to the first and second end members.
65. A spinal rod system comprising: first and second anchors having
transverse members for receiving a first coupling member and a
second coupling member, the first coupling member having an axial
end portion seated into the first anchor such that the first
coupling member is prevented from moving beyond the first anchor;
the second coupling member having an axial end portion seated into
the second anchor such that the second coupling member is prevented
from moving beyond the second anchor; an axial member operatively
connected to and extending between the first and second coupling
members; an interior section formed by the axial member, the
interior section being constructed to contain a substance
introduced into the interior section, the axial member constructed
to become elongated upon introduction of the substance into the
interior section; and a port operatively connected with the
interior section for introducing the substance, the port being
disposed in the axial member, wherein the axial member is
configured to apply a distraction force to vertebral members after
the axial end portion of the first coupling member is fixed into
the first anchor and the axial end portion of the second coupling
member is fixed into the second anchor, wherein the first coupling
member engages the first anchor and the second coupling member
engages the second anchor such that the first and second anchors
are disposed to penetrate bone in a transverse orientation in
relation to the first and second coupling members.
66. The spinal rod of claim 65 wherein the first coupling member
comprises an anchor feature extending into the interior section
from the first surface.
67. The spinal rod of claim 66 wherein the anchor feature comprises
a perforated protrusion.
68. The spinal rod of claim 66 wherein the anchor feature comprises
an enlarged head portion.
69. The spinal rod of claim 65 further comprising a third coupling
member and a second axial member, the third having a clamping
portion to be operatively connected with a vertebral member, and
the third member positioned between the intermediate section and
the second intermediate section.
Description
BACKGROUND
[0001] Spinal rods are often used in the surgical treatment of
spinal disorders such as degenerative disc disease, disc
herniations, scoliosis or other curvature abnormalities, and
fractures. Different types of surgical treatments are used. In some
cases, spinal fusion is indicated to inhibit relative motion
between vertebral bodies. In other cases, dynamic implants are used
to preserve motion between vertebral bodies. For either type of
surgical treatment, spinal rods may be attached to the exterior of
two or more vertebrae, whether it is at a posterior, anterior, or
lateral side of the vertebrae. In other embodiments, spinal rods
are attached to the vertebrae without the use of dynamic implants
or spinal fusion.
[0002] Spinal rods may provide a stable, rigid column that
encourages bones to fuse after spinal-fusion surgery. Further, the
rods may redirect stresses over a wider area away from a damaged or
defective region. Also, a rigid rod may restore the spine to its
proper alignment. In some cases, a flexible rod may be appropriate.
Flexible rods may provide some advantages over rigid rods, such as
increasing loading on interbody constructs, decreasing stress
transfer to adjacent vertebral elements while bone-graft healing
takes place, and generally balancing strength with flexibility. One
disadvantage with conventional rods is that their length, which may
span several vertebrae, may require large surgical incisions to
implant the rod. Therefore, surgical procedures requiring the
installation of an elongated rod have often required invasive open
procedures that are more costly to perform, and potentially more
dangerous and more painful for the patient.
SUMMARY
[0003] Illustrative embodiments disclosed herein are directed to a
spinal rod that has first and second end members. The first and
second end members may comprise a clamping portion for coupling
with a vertebral member. In different embodiments, the end members
may be flexible or rigid. An expandable intermediate section is
positioned between the first and second end members. The
intermediate section may be axially expandable upon the
introduction of a substance into a port that may be located in
either of the first and second end members or the intermediate
section. Further, the port may be axially or radially located on
the rod. The substance may be a fluid, such as a curable liquid.
The intermediate section may be expandable between a first size,
where the first and second end members are spaced a first distance
apart, and a second enlarged size, where the first and second end
members are spaced a second greater distance apart. The
intermediate section may be flexible or rigid. The rod may be
configured to span two or more vertebrae.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a perspective view of first and second assemblies
comprising spinal rods attached to vertebral members according to
one embodiment;
[0005] FIG. 2 is a lateral view of a spinal rod according to one
embodiment;
[0006] FIG. 3 is a cross section view of a spinal rod according to
one embodiment;
[0007] FIG. 4 is a cross section view of a spinal rod according to
one embodiment;
[0008] FIG. 5 is a cross section view of a spinal rod according to
one embodiment;
[0009] FIGS. 6A and 6B are lateral views of a spinal rod in
extended and compressed states according to one embodiment;
[0010] FIGS. 7A and 7B are lateral views of a spinal rod in
compressed and extended states according to one embodiment;
[0011] FIGS. 8A and 8B are lateral views of a spinal rod in
compressed and extended states according to one embodiment;
[0012] FIG. 9 is a lateral view of a spinal rod according to one
embodiment;
[0013] FIG. 10 is a lateral view of a spinal rod according to one
embodiment;
[0014] FIGS. 11-13 illustrate a surgical implantation process for a
rod according to one embodiment; and
[0015] FIGS. 14-15 illustrate a surgical implantation process for a
rod according to one embodiment.
DETAILED DESCRIPTION
[0016] The various embodiments disclosed herein are directed to
spinal rods that are characterized by at least one expandable
portion. The expandable portion may be compressed or left unfilled
during installation of the rod and may be filled with an injectable
substance once the rod is positioned within the body. Various
embodiments of a spinal rod may be implemented in a spinal rod
assembly of the type indicated generally by the numeral 20 in FIG.
1. FIG. 1 shows a perspective view of first and second spinal rod
assemblies 20 in which spinal rods 10 are attached to vertebral
members V1 and V2. In the example assembly 20 shown, the rods 10
are positioned at a posterior side of the spine, on opposite sides
of the spinous processes SP. Spinal rods 10 may be attached to a
spine at other locations, including lateral and anterior locations.
Spinal rods 10 may also be attached at various sections of the
spine, including the base of the skull and to vertebrae in the
cervical, thoracic, lumbar, and sacral regions. In one embodiment,
a single rod 10 is attached to the spine. Thus, the illustration in
FIG. 1 is provided merely as a representative example of one
application of a spinal rod 10.
[0017] In one embodiment as illustrated in FIG. 1, the spinal rods
10 are secured to vertebral members V1, V2 by pedicle assemblies 12
comprising a pedicle screw 14 and a retaining cap 16. The outer
surface of spinal rod 10 is grasped, clamped, or otherwise secured
between the pedicle screw 14 and retaining cap 16. Other mechanisms
for securing spinal rods 10 to vertebral members V1, V2 include
hooks, cables, and other such devices. Examples of other types of
retaining hardware include threaded caps, screws, and pins. Spinal
rods 10 are also attached to plates in other configurations. Thus,
the exemplary assemblies 12 shown in FIG. 1 are merely
representative of one type of attachment mechanism.
[0018] FIG. 2 shows an isolated view of a spinal rod 10 of the type
used in the exemplary assembly 20 in FIG. 1. The exemplary rod 10
includes an expandable portion 30. A first rod end 32 is shown
attached to the left side of the expandable portion 30 in the view
provided. A second rod end 34 is also shown attached to the right
side of the expandable portion 30. The first and second rod ends
32, 34 further include a clamping portion 33 and an enlarged flange
portion 35. The clamping portion 33 may be sized to fit within
conventional rod securing devices such as those shown in FIG. 1 and
described above. For example, the clamping portion 33 may have a
diameter within a range between about 4 and 7 mm. The rod ends 32,
34 may be constructed from a variety of surgical grade materials.
These include metals such as stainless steels, cobalt-chrome,
titanium, and shape memory alloys. Non-metallic rods, including
polymer rods made from materials such as PEEK and UHMWPE, are also
contemplated. The spinal rod 10 may have rigid or flexible rod ends
32, 34.
[0019] The expandable portion 30 is axially expandable along the
longitudinal axis A of the rod 10 as indicated by the arrows
labeled X. In one or more embodiments, the rod 10 may be expanded
through the introduction of an injectable substance that contacts
the first and second rod ends 32, 34, thereby causing the first and
second rod ends 32, 34 to move opposite one another. Various
techniques may be used to introduce the injectable substance into
the expandable portion 30. For example, one embodiment of a rod 10a
depicted in FIG. 3 includes a cannulated second rod end 34a. The
duct 36 within the second rod end 34a connects an interior volume
38 with the exterior of the rod 10a. The interior volume 38 is
defined by the first and second rod ends 32a, 34a and an expandable
outer sheath 42. In the embodiment shown, the sheath 42 connects
the first and second rod ends 32a, 34a. In one embodiment, the
sheath 42 is constructed of a flexible biomedical grade material
including resins, polymers, and metals. An injectable substance may
flow through the duct 36 into the interior volume 38 of the
expandable portion 30 from an end 40 of the second rod end 34a. As
the injectable substance fills the interior volume 38, the
substance contacts surfaces 45 and 49, thus forcing the second rod
end 34a to separate from the first rod end 32a as indicated by the
arrow labeled X. In one embodiment, the rod 10a comprises a
self-sealing valve 42 that prevents the injectable substance from
escaping once the interior volume 38 is filled. In one embodiment,
the self-sealing valve 42 is a check valve that is incorporated
along the duct 36 to allow the injectable substance to flow towards
the interior volume 38, but not out of the duct 36.
[0020] A variety of injectable substances may be inserted into the
interior volume to cause the expandable portion 30 to expand. In
one embodiment, the injectable substance is a fluid, such as a gas
or a liquid. In one embodiment, the injectable substance is a
solid, such as a powder. In one embodiment, the injectable
substance is a curable liquid that solidifies after a predetermined
amount of time or under the influence of an external catalyst. For
instance, an injectable liquid may cure under the influence of heat
or light, including ultraviolet light. Some examples of in situ
curable liquids include epoxy, PMMA, polyurethane, and
silicone.
[0021] The exemplary rod 10a shown in FIG. 3 includes a first
perforated protrusion 44 coupled to the first rod end 32a and
extending inward from a surface 45. Similarly, the rod 10a includes
a second perforated protrusion 48 coupled to the second rod end 34a
and extending inward from a surface 49. The first perforated
protrusion 44 includes a plurality of holes 46 that allow the
injectable substance to flow into or out of the first perforated
protrusion 44. Similarly, the second perforated protrusion 48
includes a plurality of holes 50 that allow the injectable
substance to flow into or out of the second perforated protrusion
48. In embodiments where the injectable substance comprises a
curable liquid, the first and second perforated protrusions 44, 48
may provide an increased amount of surface area for a curable
liquid to adhere. This may provide a more secure bond between the
curable liquid and the first and second rod ends 32a, 34a.
[0022] In one embodiment, the first and second perforated
protrusions 44, 48 are cylindrical. In one embodiment, the first
perforated protrusion 44 is larger than the second perforated
protrusion 48. Thus, in the event the first and second rod ends
32a, 34a are pushed together as indicated by the arrow labeled Y,
the second perforated protrusion 48 may fit substantially within
the first perforated protrusion 44. In this scenario, the first
perforated protrusion 44 may contact the second rod end 34a.
Alternatively, the second perforated protrusion 48 may contact the
first rod end 32a. In either case, overcompression of the sheath 42
and damage thereto may be avoided.
[0023] An alternative embodiment of a rod 10b is depicted in FIG.
4. In this embodiment, the first and second rod ends 32b, 34b are
shown as solid members, though this is not expressly required. The
exemplary sheath 52 surrounding the interior volume 54 is an
accordion-style bellows. In one embodiment, the sheath 52 is
reinforced with a woven or braided structure. In one embodiment,
the sheath 52 is reinforced with coiled or concentric wires 56. The
concentric wires 56 may be comprised of a biocompatible metal such
as stainless steel, titanium alloys, or nitinol. The interior
volume 54 of the expandable portion 30b may be filled through a
self-sealing valve 58 that prevents an injectable substance from
escaping once the interior volume 38 is filled.
[0024] FIG. 5 shows an alternative embodiment of a rod 10c that is
similar to rod 10a. For instance, the second perforated protrusion
48 and the holes contained thereon 50 are substantially the same on
both embodiments of the rod 10a, 10c. In rod 10c, the expandable
portion 30c is defined in part by a folded sheath 142 having pleats
that overlap one another. When the expandable portion 30c expands
under the influence of an injected substance, the folded sheath 142
unfolds to an extended state, such as that shown in FIG. 1.
[0025] The first rod end 32c has a plurality of anchors 60
comprising a stem portion 62 and an enlarged head portion 64. In
embodiments where the injectable substance comprises a curable
liquid, the cured material may harden in the undercuts adjacent the
stem portion 62, between the head portion 64 and the first rod end
32c. The anchors 60 may provide a more secure bond between the
curable liquid and the first rod end 32c.
[0026] The exemplary rod 10c also has a cannulated second rod end
34c with a duct 66 connecting the interior volume 138 with an
injection port 68. In the embodiment shown, the injection port 68
is located at a side of the rod end 34c. In one embodiment, the
injection port 68 is radially disposed. This is in contrast to the
axially disposed port and valve 42 shown in FIG. 3. Injectable
materials may be introduced into the duct 66 through the port 68
and ultimately flow into interior volume to expand the expandable
portion 30c. In one embodiment, the rod 10c comprises a
self-sealing valve 70 that prevents the injectable substance from
escaping once the interior volume 38 is filled. In one embodiment,
the self-sealing valve 70 is a check valve that is incorporated
along the duct 66 to allow the injectable substance to flow towards
the interior volume 38, but not out of the duct 66. In an
alternative embodiment, the self-sealing valve 70 may be disposed
at the injection port 68.
[0027] FIGS. 6A and 6B illustrate an alternative embodiment of a
rod 10d that is characterized by a telescoping expandable portion
30d. In contrast with previous embodiments that use a flexible
sheath or bellows design, the illustrated rod 10d has a series of
concentric columns 72 that are able to collapse within one another
in the absence of an injectable material within the expandable
portion 30d. FIG. 6B illustrates the collapsed rod 10d. However,
upon filling the expandable portion 30d with the injectable
material, the concentric columns 72 expand or telescope to the
expanded position illustrated in FIG. 6A. In one embodiment, the
concentric columns 72 are substantially cylindrical. In one
embodiment, the concentric columns 72 have a substantially
non-circular cross section, including for example, square, oval,
star, or polygonal shapes. In one embodiment, the end portions 32,
34 may themselves form concentric columns 72 with the expandable
portion 30d being a cavity formed in one or both of the end
portions 32, 34. The concentric columns 72 may have seals (not
shown) to prevent the injectable substance from escaping once the
expandable portion 30d is filled.
[0028] FIGS. 7A and 7B illustrate an exemplary rod 10e having
different rod ends 32e, 34e than those provided on embodiments
described above. In this particular embodiment, the rod ends 32e
and 34e do not have an enlarged flange. Instead, the expanding
portion 30e is coupled directly to clamping portions 33.
Consequently, when the expandable portion 30e is filled with an
injectable substance as shown in FIG. 7B, the rod 10e has an outer
width D that is substantially uniform over the entire length of the
rod 10e. Also, the rod 10e (or other rods 10 described herein) may
have an extended length L that is sufficient to span at least one
vertebral pair. Thus, the length L may be in the range between
about 30-40 mm or greater as needed. Rod 10e may also have a
cannulated second rod end 34e. Other means of introducing an
injectable substance may be incorporated into rod 10e. This
includes variations described above such as the radial insertion
points in the rod end 32e, 34e or in the expandable portion
30e.
[0029] FIGS. 8A and 8B illustrate an alternative configuration
where rod 10f includes an expandable portion 30f constructed of a
non-compliant, flexible material 74. That is, the flexible material
74 is balloon-like in that it does not assume any particular shape
when unfilled as shown in FIG. 8A. Further, the flexible material
74 of the expandable portion 30f is capable of expanding to a width
that is larger than the width of the rod ends 32f, 34f as shown in
FIG. 8B.
[0030] In embodiments discussed above, the exemplary rods 10 have
generally comprised an expandable portion 30 disposed between two
rod ends 32, 34. In other embodiments, such as those illustrated in
FIGS. 9 and 10, the rods 10g, 10h are comprised of a plurality of
expandable portions 30 disposed in an alternating manner between
clamping portions 33. With this multi-level configuration, the rods
10g, 10h may be attached to several vertebrae. In the embodiments
shown, two expandable portions 30 are arranged in an alternating
manner between three clamping portions 33. Accordingly, these
embodiments may be attached at three points, possibly at three
different vertebrae. Rods 10 comprising a larger number of
expandable portions 30 and clamping portions 33 are certainly
feasible.
[0031] The embodiments illustrated in FIGS. 9 and 10 include
multiple expandable portions 30 with each portion 30 having
substantially the same size and construction. In some embodiments,
the portions 30 have different sizes. In some embodiments, each of
the portions 30 is a different type.
[0032] The various rods 10 disclosed herein may be surgically
implanted using a variety of techniques. Certainly, full-open
surgical procedures that are used to install conventional rods may
be used. However, the compressibility of the expandable portion 30
of the rods 10 described herein permits more minimally invasive
surgical procedures. FIG. 11 illustrates one such procedure where a
mini-open procedure (i.e., with a small surgical incision) is used.
FIG. 11 shows a segment of a spine that includes three vertebrae
V1, V2, V3 and two discs D1, D2. In this embodiment, the surgical
procedure may be necessary to repair a diseased or defective disc
D1. Accordingly, a vertebral implant I may be inserted between
vertebrae V1 and V2. Pedicle screws 14 similar to those shown in
FIG. 1 are inserted into vertebrae V1 and V2 in preparation for the
installation of a rod 10. Specifically, FIG. 11 shows rod 10b from
FIG. 4 in a compressed and folded condition to pass through a small
opening in the subject S. Rod 10b is shown in FIGS. 11-13 for
illustrative purposes. In other embodiments, one or more of the
other rod 10 embodiments may be inserted using this surgical
technique. The opening in the subject S may be widened as needed to
allow the rod 10b to pass. The widening may be accomplished using
retractors R. Alternatively, the opening may be maintained between
screw extenders that are coupled to the installed pedicle screws
14. A dashed-line representation of a portion of exemplary screw
extenders is shown in FIG. 11 and identified by the label SE.
[0033] The rod 10b is placed into the subject S using an insertion
tool, a representation of which is shown in dashed lines and
labeled T. Then, the rod 10b is positioned onto the pedicle screws
14 as shown in FIG. 12. At this point, the rod 10b, and
particularly the expandable portion 30b remain in a compressed
state. Once the rod 10b is positioned as shown, a needle N or other
injection instrument is used to inject the injectable substance
into the self-sealing valve 58 on the expandable portion 30b. Note
that with other embodiments, the injectable substance may be
injected into other portions of the rod 10 such as radially or
axially into the rod end 34.
[0034] As the injectable substance is placed into the expandable
portion 30b, the rod ends 32, 34 separate from each other until the
enlarged flanges 35 at each rod end 32, 34 contact the head of the
pedicle screws 14. The expanded rod 10b is illustrated in FIG. 13.
At this point, the rod 10b is fully seated and a suitable clamping
device (e.g., retaining cap 16 shown in FIG. 1) can be used to
secure the clamping portion 33 to the pedicle screws 14. In an
alternative approach, the clamping portions 33 may be secured to
the pedicle screws 14 prior to the insertion of some or all of the
substance. For example, inserting additional substance into the rod
10b after the clamping portions 33 are secured to the pedicle
screws 14 may provide some desired distraction of the vertebrae to
which the pedicle screws 14 are attached.
[0035] An alternative installation approach contemplates a
minimally invasive percutaneous procedure as shown in FIGS. 14 and
15. The procedure shown in FIG. 14 incorporates an installation
instrument 20. One example of an instrument suitable for this type
of installation is the Sextant Rod Insertion System available from
Medtronic Sofamor Danek in Memphis, Tenn., USA.
[0036] The installation instrument includes support arms 78 that
are coupled to pedicle screw extensions 76. The support arms 78 are
pivotally connected to a rod holder 82 about pivot P. As with the
previous method shown in FIGS. 11-13, this procedure may include
removing some or all of an intervertebral disc D1 from the space
between first V1 and second V2 vertebral bodies through one
percutaneous puncture in the subject. An implant I is introduced
into the disc space. Implant I may be an interbody fusion device or
the like as is known in the art. The first and second pedicle
screws 14 and pedicle screw extensions 76 are engaged to the first
and second vertebrae V1, V2, respectively, through second and third
percutaneous punctures in the subject S. If desired, a surgeon can
manipulate the pedicle screw extensions 76 to apply a load to
compress or distract the vertebrae V1, V2 prior to installing rod
10e. Rod 10e is shown for illustrative purposes. Any of the other
rod 10 embodiments may be inserted using this technique. The rod
10e is installed through a fourth percutaneous puncture in the
subject S using the installation instrument 20. The rod 10e is
brought into engagement with the pedicle screws 14 by rotating the
rod holder 82 about pivot P.
[0037] In one embodiment, the rod holder 82 is cannulated to allow
a surgeon to introduce an injectable substance through the rod
holder 82 and into the rod 10e. A needle or other injection
instrument is used to inject the injectable substance into the port
J in the rod holder 82. As the injectable substance is inserted
into the expandable portion 30e, the rod ends 32, 34 separate from
each other until the clamping portions 33 at each rod end 32, 34
lie within the head of the pedicle screws 14. This is illustrated
in FIG. 15. At this point, the rod 10e is fully seated and a
suitable clamping device (e.g., retaining cap 16 shown in FIG. 1)
can be used to secure the clamping portion 33 to the pedicle screws
14.
[0038] Since the rod 10 includes clamping surfaces 33 on either
side of an expandable portion 30, a surgeon may clamp down on the
rod ends 32, 34 regardless of the phase of the injectable material.
That is, regardless of whether the injectable substance is gaseous,
liquid, or an uncured liquid, the surgeon may secure the rod 10 to
the pedicle screws 14 or other clamping mechanism once the rod ends
32, 34 have expanded to the desired position. This aspect also
means a surgeon may be able to secure the rod ends 32, 34 without
having to wait for a curable injectable substance to set.
[0039] Spatially relative terms such as "under", "below", "lower",
"over", "upper", and the like, are used for ease of description to
explain the positioning of one element relative to a second
element. These terms are intended to encompass different
orientations of the device in addition to different orientations
than those depicted in the figures. Further, terms such as "first",
"second", and the like, are also used to describe various elements,
regions, sections, etc and are also not intended to be limiting.
Like terms refer to like elements throughout the description.
[0040] As used herein, the terms "having", "containing",
"including", "comprising" and the like are open ended terms that
indicate the presence of stated elements or features, but do not
preclude additional elements or features. The articles "a", "an"
and "the" are intended to include the plural as well as the
singular, unless the context clearly indicates otherwise.
[0041] The present invention may be carried out in other specific
ways than those herein set forth without departing from the scope
and essential characteristics of the invention. For example,
embodiments described above have contemplated end members 32, 34
that have a substantially similar overall shape. However, this is
not explicitly required. For instance, other embodiments may
include an end member at one end or an intermediate location having
a flange while end members in other locations do not have a flange.
The present embodiments are, therefore, to be considered in all
respects as illustrative and not restrictive, and all changes
coming within the meaning and equivalency range of the appended
claims are intended to be embraced therein.
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