U.S. patent application number 12/697950 was filed with the patent office on 2010-06-03 for adjustable rod and connector device.
Invention is credited to Stephen RITLAND.
Application Number | 20100137914 12/697950 |
Document ID | / |
Family ID | 32930544 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100137914 |
Kind Code |
A1 |
RITLAND; Stephen |
June 3, 2010 |
ADJUSTABLE ROD AND CONNECTOR DEVICE
Abstract
A low-profile surgical rod implant device is provided that
allows the length of a rod spanning two bone screws to be adjusted
at the time of implantation. In a separate aspect of the invention,
the rod implant device can be secured by tightening and securing an
end of the rod implant device at one of the bone screws.
Embodiments are provided for use with polyaxial pedicle screws and
substantially straight shank pedicle screws in spinal applications.
In a separate aspect of the invention, a bone screw connector
having an interference type fit is also provided. A method for
implanting the device is also provided.
Inventors: |
RITLAND; Stephen;
(Flagstaff, AZ) |
Correspondence
Address: |
HOLME ROBERTS & OWEN LLP
1700 LINCOLN STREET, SUITE 4100
DENVER
CO
80203
US
|
Family ID: |
32930544 |
Appl. No.: |
12/697950 |
Filed: |
February 1, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11069390 |
Mar 1, 2005 |
7655025 |
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12697950 |
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10788172 |
Feb 25, 2004 |
6991632 |
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11069390 |
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10262574 |
Sep 30, 2002 |
7207992 |
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10788172 |
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60325809 |
Sep 28, 2001 |
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60450179 |
Feb 25, 2003 |
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60460195 |
Apr 4, 2003 |
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Current U.S.
Class: |
606/258 ;
606/264 |
Current CPC
Class: |
A61B 17/7004 20130101;
A61B 17/7014 20130101; Y10T 403/7077 20150115; A61B 17/7037
20130101; A61B 17/7007 20130101 |
Class at
Publication: |
606/258 ;
606/264 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Claims
1.-19. (canceled)
20. In subcombination, a rod member for use with a bone stabilizing
rod, the rod member comprising: a. an upper arm; b. a lower arm
interconnected to said upper arm, wherein at least a portion of
said lower arm is separated from said upper arm by a slot and a
hollow chamber, said hollow chamber sized to receive at least a
portion of the bone stabilizing rod; wherein said upper arm is
moveable to compress and secure the portion of the bone stabilizing
rod between an interior surface of said upper arm and an interior
surface of said lower arm.
21. The subcombination of claim 20, wherein the rod member further
comprises a distal opening for receiving at least a portion of the
bone stabilizing rod, wherein said distal opening is formed within
a hoop structure connected to the upper arm and separated from said
lower arm by a notch.
22. The subcombination of claim 21, wherein said lower arm further
comprises an end connector adapted for interconnection to a bone
screw.
23. In subcombination, a deformable connector for use with a
stabilizing rod clamp, the deformable connector securing a portion
of a substantially cylindrical member within a cavity in the
stabilizing rod clamp, the deformable connector comprising: a. a
disc having a passageway adapted to receive the substantially
cylindrical member; b. a groove along an exterior surface of said
disc and extending to said passageway; wherein said disc is
compressible to secure the substantially cylindrical member within
said passageway upon application of a compressing force to said
disc.
24. The subcombination of claim 23, wherein at least a portion of
said disc comprises a skeletonized structure.
25. The subcombination of claim 23, wherein at least a portion of
said disc has a truncated exterior surface.
26. The subcombination of claim 23, wherein said disc comprises an
indentation along a portion of said exterior surface.
27. A connector device for a bone screw, comprising: a clamp
including an upper section and a lower section separated by a slot,
said upper section including a first aperture and said lower
section including a second aperture substantially aligned with said
first aperture, said first and second apertures sized to
accommodate a shank of the bone screw; and a tightening member
operatively connected to said upper section and said lower section,
wherein upon advancing said tightening member, said tightening
member reduces the size of said slot between said upper section and
said lower section, thereby securing the shank of the bone screw
within the connector device.
28. The connector device as claimed in claim 27, wherein said
tightening member is a screw or a bolt.
29. The connector device as claimed in claim 27, wherein said clamp
is substantially C-shaped.
30. The connector device as claimed in claim 27, further comprising
a beam interconnected to said clamp.
Description
CROSS REFERENCE AND PRIORITY CLAIMS TO RELATED APPLICATION
[0001] This application is a continuation application of U.S.
patent application Ser. No. 10/788,172 filed on Feb. 25, 2004,
which is a continuation-in-part application of U.S. patent
application Ser. No. 10/262,574 filed Sep. 30, 2002, entitled
"Connection Rod For Screw or Hook Polyaxial System And Method of
Use", which claimed priority to U.S. Provisional Patent Application
No. 60/325,809 filed Sep. 28, 2001, entitled "Connection Rod For
Screw or Hook Polyaxial System And Method of Use"; U.S. patent
application Ser. No. 10/788,172 filed on Feb. 25, 2004 also claimed
priority to U.S. Provisional Patent Application No. 60/450,179
filed Feb. 25, 2003 entitled "Connection Rod For Screw or Hook
Polyaxial System And Method of Use", and to U.S. Provisional Patent
Application No. 60/460,195 filed Apr. 4, 2003 entitled "Sliding
Connector". The entire disclosures of these applications are
considered to be part of the disclosure of the present application
and are hereby incorporated by reference in their entirety. Cross
reference is also made to U.S. Pat. No. 6,736,816 entitled
"Polyaxial Connection Device and Method" that issued on May 18,
2004, which is also incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates generally to an adjustable rod and
connectors for stabilizing a portion of the spine or stabilizing
two or more bone segments, and a method of using the same.
BACKGROUND OF THE INVENTION
[0003] The use of fixation devices for the treatment of vertebrae
deformities and injuries is well known in the art. Various fixation
devices are used in medical treatment to correct curvatures and
deformities, treat trauma and remedy various abnormal spinal
conditions.
[0004] The prior art fails to provide a low-profile device that
allows the rod length to be easily adjusted during implantation
with a minimal amount of effort by the installing surgeon. More
particularly, where at least two bones or bone segments are
involved, such as a first vertebra and a second vertebra, the rod
typically extends beyond the connector, and needs to be
specifically chosen or otherwise cut to accommodate the dimensions
of the subject patient. Therefore, a need exists to provide an
adjustable length rod implantation assembly and component parts
that can be installed relatively easily by a surgeon, and that has
the ability to be adjusted at the moment of implantation to thereby
accommodate the geometry requirements of the patient.
[0005] The prior art also fails to provide pedicle screw to rod
connectors that can be easily adjusted at the time of implantation.
Such devices are needed to further accommodate the individual
patient's requirements that exist and that are encountered upon
performing and incision and encountering in situ conditions.
[0006] In view of the above, there is a long felt but unsolved need
for devices and methods that avoid the above-mentioned deficiencies
of the prior art and that are relatively simple to employ and
require relatively minimal displacement or removal of bodily
tissue.
SUMMARY OF THE INVENTION
[0007] The present invention addresses the shortcomings of the
prior art. More specifically, implant assemblies and/or components
of an implant are provided that allow a surgeon to adjust the
implant for the patient's requirements as they are encountered
during surgery, and/or which allow the surgeon to use low-profile
implant components that result in minimal displacement of bodily
tissue.
[0008] The above and other aspects of the invention are realized in
specific illustrated embodiments of the invention, and components
thereof. Thus, in one aspect of the present invention, a spinal rod
implant for spanning at least one intervertebral disc is provided.
The implant is interconnectable to a first vertebra using a first
pedicle screw, and to a second vertebra using a second pedicle
screw. The first pedicle screw is separated from the second pedicle
screw by a bridge distance. The implant comprises a first rod
member for interconnecting to the first vertebra, where the first
rod member includes a beam having an effective length shorter than
the bridge distance. The implant also includes a second rod member
for interconnecting to the second vertebra, where the second rod
member includes a clamp sized to receive at least a portion of the
beam. The clamp also has an effective length shorter than the
bridge distance. In addition, the implant includes a means for
tightening the clamp to create a force to secure the beam within
the clamp.
[0009] In a separate aspect of the invention, a surgical implant is
provided, where the implant comprises a first rod member including
a beam and a second rod member including an opening sized to
circumferentially receive the beam. The second rod member also
includes an interior hollow chamber for longitudinally receiving at
least a portion of the beam. In addition, the second rod member
includes an upper arm and an opposing lower arm spaced apart by a
slot, wherein the slot is contiguous with the interior hollow
chamber. The upper arm is moveable to contact the beam and compress
the beam between the upper arm and the lower arm. In addition, the
implant includes a means for tightening the second rod member to
secure the beam within the second rod member.
[0010] A component of the assembly also has application to devices
other than a rod implant that is parallel to the spine and that
spans an intervertebral disc. For example, the clamp component
could be used in bone stabilization unrelated to the spine.
Alternatively, it could be used in rod extensions, or it could be
adapted for use in cross-link assemblies that are used to
structurally interconnect right and left stabilization assemblies
that are implanted on either side of a spinous process. Thus, it is
one aspect of the present invention to provide a rod member for use
with a bone stabilizing rod, the rod member comprising and an upper
arm and a lower arm interconnected to the upper arm. At least a
portion of the lower arm is separated from the upper arm by a slot
and a hollow chamber, where the hollow chamber is sized to receive
at least a portion of the bone stabilizing rod. The upper arm is
moveable to compress and secure the portion of the bone stabilizing
rod between an interior surface of the upper arm and an interior
surface of the lower arm.
[0011] One embodiment of the present invention features a rod
clamping component that can be used in conjunction with a TSRH 3D
pedicle screw known to those skilled in the art. The clamping
component includes a deformable connector that preferably resides
within a cavity in the rod clamping component. The deformable
connector has potential application to being used with structures
other than pedicle screws. For example, the deformable connector
can be used with a properly adapted stabilizing rod that is used
for bones other than the spine. Thus, it is one aspect of the
present invention to provide a deformable connector for use with a
stabilizing rod clamp, the deformable connector capable of securing
a portion of a substantially cylindrical member, such as a shank of
a TSRH 3D pedicle screw or a stabilizing rod, within a cavity in
the stabilizing rod clamp. The deformable connector preferably
comprises a disc having a passageway adapted to receive the
substantially cylindrical member. In addition, the deformable
connector preferably includes a groove along an exterior surface of
the disc and extending to the passageway. When compressed within
the stabilizing rod clamp, the disc secures the cylindrical member
within the passageway.
[0012] It is further desirable to provide a low-profile connector
that can be easily used in combination with a shank of a bone
screw. In a separate embodiment, low profile connector is provided
that utilizes an interference-type fit to secure the connector to
the shank of the bone screw. Thus, it is one aspect of the present
invention to provide a connector device for a bone screw, the
connector device comprising a clamp that includes an upper section
and a lower section separated by a slot. The upper section includes
a first aperture and the lower section includes a second aperture
substantially aligned with the first aperture, where the first and
second apertures are sized to accommodate a shank of the bone
screw. The connector further includes a tightening member
operatively connected to the upper section and the lower section.
The tightening member tightens the clamp and reduces the size of
the slot between the upper section and the lower section. This
secures the shank of the bone screw within the device.
[0013] It is a further aspect of the present invention to provide a
bone stabilization assembly for securing a first bone segment to a
second bone segment. This has particular application to being used
to bridge an intervertebral disc between two vertebra. The assembly
comprises a first bone screw attachable to the first bone segment
and a second bone screw attachable to the second bone segment. In
addition, the assembly includes a first rod member including a beam
and an end connector, where the end connector is attachable to the
first bone screw. Also, the assembly includes a second rod member.
The second rod member includes an interior hollow chamber for
longitudinally receiving at least a portion of the beam of the
first rod member. The second rod member includes an upper arm and
an opposing lower arm, where the upper arm and the lower arm are
spaced apart by a slot, and wherein the slot is contiguous with the
interior hollow chamber. The upper arm is moveable and/or
deformable to contact the beam and compress the beam between the
upper arm and the lower arm. In addition, the second rod member
includes a connector attachable to the second bone screw. The
assembly also includes a means for tightening the second rod member
to secure the beam within the second rod member.
[0014] The present invention also includes various methods for
using the devices presented herein. One such method concerns
stabilizing one or more vertebra using an assembly. Thus, it is one
aspect of the present invention to provide a method of stabilizing
a first vertebra to a second vertebra. The method comprises the
steps of attaching a first pedicle screw to the first vertebra and
a second pedicle screw to the second vertebra. In addition, the
method includes a step of inserting a beam of a first rod member
into a second rod member, where the second rod member includes an
interior hollow chamber for longitudinally receiving at least a
portion of the beam of the first rod member. The second rod member
also includes an upper arm and an opposing lower arm, where the
upper arm and the lower arm spaced apart by a slot, and wherein the
slot is contiguous with the interior hollow chamber. The upper arm
is moveable to contact the beam and compress the beam between the
upper arm and the lower arm. In addition, the second rod member
includes an integral connector for attaching the second rod member
to the second pedicle screw. The method also includes the step of
connecting the first rod member to the first pedicle screw using a
connector interconnected to the beam. In addition, the method
includes the step of advancing a single tightening mechanism to
secure (a) the second rod member to the beam of the first rod
member, and (b) the second rod member to the second pedicle
screw.
[0015] Various embodiments of the present invention are set forth
in the attached figures and in the detailed description of the
invention as provided herein and as embodied by the claims. It
should be understood, however, that this Summary of the Invention
may not contain all of the aspects and embodiments of the present
invention, is not meant to be limiting or restrictive in any
manner, and that the invention as disclosed herein is and will be
understood by those of ordinary skill in the art to encompass
obvious improvements and modifications thereto.
[0016] Additional advantages of the present invention will become
readily apparent from the following discussion, particularly when
taken together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a side elevation view of one assembly that
incorporates aspects of the present invention, wherein the assembly
includes a first embodiment of a first rod member, a first
embodiment of a second rod member, polyaxial pedicle screws,
tension links, and tension link nuts;
[0018] FIG. 2 is a side elevation view of one assembly of the
present invention shown after implantation into two vertebra;
[0019] FIG. 3 is a side elevation view of a first embodiment of a
first rod member including a beam and an end connector that
includes a socket;
[0020] FIG. 4 is a perspective view of the device shown in FIG.
3;
[0021] FIG. 5 is a perspective view of the device shown in FIG. 3
in combination with a polyaxial pedicle screw and a tension
link;
[0022] FIG. 6 is a side perspective view of a first embodiment of a
second rod member;
[0023] FIG. 7 is a reverse side elevation view of a one assembly of
the present invention;
[0024] FIG. 8a is a cross sectional view along line 8a-8a shown in
FIG. 1, wherein the beam has a circular cross section;
[0025] FIG. 8b is a cross sectional view along line 8a-8a shown in
FIG. 1, wherein the beam has an oblong-shaped cross section;
[0026] FIG. 9 is a side elevation view of a second rod member;
[0027] FIG. 10 is a bottom perspective view of a second rod
member;
[0028] FIG. 11 is a bottom perspective view of a first rod member
within a second rod member;
[0029] FIG. 12 is a top perspective view of a first rod member
within a second rod member;
[0030] FIG. 13 is a side elevation view of a second rod member
having a recess on its upper arm and projection on its lower
arm;
[0031] FIG. 14 is a side elevation view of a second embodiment of a
second rod member that includes a deformable connector;
[0032] FIG. 15 is a side elevation view of a second embodiment of a
first rod member that includes a deformable connector;
[0033] FIG. 16a is a side perspective view of one version of a
deformable connector or disc;
[0034] FIG. 16b is a side perspective view of a second version of a
deformable connector or disc, wherein the disc includes a side
grove;
[0035] FIG. 17 is a plan view of the device shown in FIG. 16b;
[0036] FIG. 18 is a side elevation view of the device shown in FIG.
16b in combination with a pedicle screw having a substantially
straight upper shank portion;
[0037] FIG. 19 is a side elevation view of a modified version of
the device shown in FIG. 16b;
[0038] FIG. 20 is a plan view of a yet a different version of the
device shown in FIG. 16b, wherein the device of FIG. 20 is
spherical in shape rather than disc shaped;
[0039] FIG. 21 is a side elevation view of the device shown in FIG.
20;
[0040] FIG. 22 is a side elevation view of one assembly that
incorporates aspects of the present invention, wherein the assembly
includes a third embodiment of a first rod member, a second
embodiment of a second rod member;
[0041] FIG. 23 is a plan view of the assembly shown in FIG. 22;
[0042] FIG. 24 is a side elevation view of the third embodiment of
a first rod member shown in FIG. 22;
[0043] FIG. 25 is a plan view of the device shown in FIG. 24;
[0044] FIG. 26 is a side elevation view of separate embodiment of
the device shown in FIG. 24;
[0045] FIG. 27 is a plan view of an assembly having a second
embodiment of the second rod member, wherein the deformable
connector of the second rod member has an indentation that
cooperates with the tightening member;
[0046] FIG. 28 is a side elevation view of one assembly that
incorporates aspects of the present invention, wherein the assembly
includes a first embodiment of a first rod member, a second
embodiment of a second rod member;
[0047] FIG. 29 is a plan view of a second embodiment of a
deformable connector, wherein the deformable connector has a
skeletonized structure;
[0048] FIG. 30 is a side elevation view of the deformable connector
shown in FIG. 29, in combination with a pedicle screw having a
substantially straight upper shank portion.
[0049] While the following disclosure describes the invention in
connection with those embodiments presented, one should understand
that the invention is not strictly limited to these embodiments.
Furthermore, one should understand that the drawings are not
necessarily to scale, and that in certain instances, the disclosure
may not include details which are not necessary for an
understanding of the present invention, such as conventional
details of fabrication.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0050] Referring to FIG. 1, a first embodiment of an adjustable rod
implant 10 is shown. The adjustable rod implant 10 is preferably a
multi-piece implant, and more preferably, a two-piece rod implant.
By way of example and without limitation, the adjustable rod
implant 10 can be used as a structural bridge to span a section of
bone, or to span a distance between two portions of bone, or to
span a distance between two different bones. As shown in FIG. 2, in
one anticipated use, the adjustable rod implant 10 can be used as a
vertebral bridge to span at least one intervertebral disc D between
two vertebra V.sub.1 and V.sub.2. Accordingly, by way of
illustration and without intending to limit the possible uses of
the present invention, the examples of usage presented herein are
generally directed toward spanning at least one intervertebral
disc.
[0051] The adjustable rod implant 10 is preferably attached to the
subject vertebrae using pedicle screws, with a connector
interconnecting the pedicle screws to the adjustable rod implant
10. The pedicle screws used with the adjustable rod implant 10 may
be of a type that allow for some rotational or polyaxial adjustment
prior to securing the adjustable rod implant 10, as discussed
further below, or the pedicle screws may be of the type that do not
allow rotational or polyaxial adjustment. The adjustable rod
implant could be used with other types of bone pedicle screws. For
example, although not shown, instead of pedicle screws, the rod
implant may be used with hook devices that attach to the vertebrae,
such hook devices being known to those skilled in the art.
[0052] Referring again to FIG. 1, the adjustable rod implant 10
includes a first rod member 12. The first rod member 12 includes a
rod or beam 14. As best shown in FIG. 3, the beam 14 has a
longitudinal axis LA.sub.b-LA.sub.b. Beam 14 has a first beam end
or distal beam end 16 and a second beam end or proximate beam end
18. The beam 14 also includes a posterior or top side 20 and an
anterior or bottom side 22. The beam 14 may have a solid interior
or it may have a hollow interior, depending upon the strength
requirements of the particular application in which it is being
used. For most spinal surgeries, it is anticipated that beam 14
will be solid.
[0053] First rod member 12 may be interconnected to a pedicle screw
using a separate connector that is not an integral part of first
rod member 12. Alternatively, an integral connector may be used.
For the embodiment shown in FIG. 1, first rod member 12 includes an
end connector 24 attached to the proximate beam end 18 of beam 14.
End connector 24 is used to interconnect beam 14 to a pedicle
screw. The end connector 24 is preferably incorporated directly
into the first rod member 12 in the form of a receptacle 26.
[0054] Referring to FIGS. 1 and 3-5, end connector 24 is shown
located at the proximate beam end 18 of a beam 14. In a preferred
embodiment, the end connector 24 is adjustable and includes a
receptacle 26 that is in the form of a socket that preferably
includes a socket exterior 28 and a socket interior 30. The socket
interior 30 essentially acts as a low-profile connector. The
receptacle 26 is sized to fit over and receivingly accept a
substantially spherical-headed pedicle screw, such as the enlarged
area 32 of a polyaxial pedicle screw 34. Accordingly, socket
interior 30 is preferably a recessed area at the proximate beam end
18 of a beam 14 that fits over the enlarged area 32 of the
polyaxial pedicle screw 34. As shown in FIGS. 1 and 3-5, the socket
interior 30 is preferably nearly spherical, to match a
spherical-type shape of enlarged area 32 of the polyaxial pedicle
screw 34. However, the socket interior 30 may be a variety of
shapes that match the head of the pedicle screw. Within the top
center area of the receptacle 26 is a tension link cavity 36 that
is sized to accommodate the shaft 38 of a tension link 40.
Referring to FIGS. 1 and 4, the tension link cavity 36 can be seen
as an opening through the top of receptacle 26.
[0055] Referring now to FIG. 3, a side perspective view of the
first rod member 12 is shown. The first rod member 12 includes the
beam 14 and preferably includes an end connector 24 that is
integrally formed with the beam 14, where the end connector 24 is
positioned at the second end 18 of the rod member 14. As discussed,
the end connector 24 includes structural features the allow the
beam 14 to be interconnected to an appropriately configured pedicle
screw S.
[0056] Referring now to FIG. 4, a top perspective view of the first
rod member 12 is shown. For embodiments having an end connector 24,
this view illustrates the tension link cavity 36 positioned at
substantially the top of the end connector 24 at the proximate beam
end 18 of the first rod member 12. The tension link cavity 36 is
sized to accommodate the diameter of the shaft 38 of a tension link
40.
[0057] Referring now to FIG. 5, a bottom perspective view of the
first rod member 12 is shown with an end connector 24, a polyaxial
pedicle screw 34, a tension link 40, and a tension link nut 58. The
substantially spherical enlarged area 32 of the polyaxial pedicle
screw 34 and the substantially spherical socket interior 30 of the
end connector 24 allows the end connector 24 to be rotated and
adjusted over the enlarged area 32 of a polyaxial pedicle screw 34
before tightening using the tension link nut 58, thus providing
adjustability to the rod, connector, and pedicle screw
configuration.
[0058] When located at the proximate beam end 18 of beam 14, the
principal advantage of the integral end connector 24 is to shrink
the profile of the configuration as a system, and thereby reduce
the length of the rod implant 10 that is longitudinally exposed
beyond the pedicle screw location. In so doing, in spinal implant
applications, the adjacent vertebra beyond the end of the first rod
member 12 is not exposed to potentially impacting a rod section
that would have previously extended longitudinally beyond the
connector location. This can reduce patient pain and increase
patient mobility. A further advantage is that the smaller profile
results in less tissue displacement in the vicinity of end
connector 24. However, it is again noted that a separate rod to
pedicle screw connector known to those skilled in the art may be
used to attach a section of rod to a pedicle screw, and therefore,
although preferred, and end connector 24 is not required.
[0059] Referring again to FIG. 1 and also FIGS. 6 and 9, the second
rod member 42 of the adjustable rod implant 10 is shown. The second
rod member 42 functions as a clamp, and is preferably a one-piece
structure that is deformable to create a compressive force and
secure the first rod member 12 within the second rod member 42 when
a means for clamping or tightening the second rod member 42 is
applied. The second rod member 42 includes an interior hollow
chamber 44. The interior hollow chamber 44 is an elongated hollow
region having a longitudinal axis LA.sub.c-LA.sub.c. The interior
hollow chamber 44 is sized to accommodate at least a portion of the
beam 14 of the first rod member 12.
[0060] Referring now to FIG. 10, the second rod member 42
preferably includes a slot 46 that separates an upper arm 48 from a
lower arm 50. The lower arm 50 acts as a base for the second rod
member 42. The slot 46 forms a gap that can be selectively reduced,
whereby the slot 46 allows the upper arm 48 to be selectively
deflected toward the lower arm 50.
[0061] As best seen in FIG. 10, the second rod member 42 also
includes a distal opening 52 that leads to the interior hollow
chamber 44. The distal opening 52 is sized to receive the beam 14.
More particularly, the distal beam end 16 of beam 14 can be
inserted into the distal opening 52, and the beam 14 selectively
slid into the interior hollow chamber 44.
[0062] Referring to FIGS. 1 and 7, adjustment arrow A.sub.1 shows
that the beam 14 may be moved from right to left and from left to
right within the interior hollow chamber 44 of the second rod
member 42 prior to applying a clamping or tightening force to the
second rod member 42. The length of the beam 14 that is slid into
the interior hollow chamber 44 can be adjusted by the surgeon.
FIGS. 11 and 12 show two different perspective views of the beam 14
of the first rod member 12 positioned within the hollow chamber 44
of the second rod member 42. Since the overall length of the
implant 10 can be adjusted at the time of the implantation by the
surgeon, this allows the surgeon to readily accommodate a patient's
particular needs.
[0063] By application of a clamping or tightening force to the
second rod member 42, the upper arm 48 and lower arm 50 are
compressed toward each other, thereby securing the beam 14 within
the second rod member 42. In the preferred embodiment shown in FIG.
1, the base or lower arm 50 remains substantially immobile, and the
upper arm 48 is deflected toward the lower arm 50. Arrows A.sub.2
of FIGS. 1 and 7 show that the upper arm 48 is forced toward the
lower arm 50. That is, the upper arm 48 acts as a moveable and/or
deformable structure that is suspended over the interior hollow
chamber 44, and which can be forced toward the lower arm 50. In so
doing, at least a portion of the interior surface 54 of the upper
arm 48 applies a compressive force to the top side 20 of the beam
14. The beam 14 then presses downward such that the bottom side 22
of the beam 14 presses against the interior surface 56 of the base
or lower arm 50 of the second rod member 42. This interaction of
forces causes the beam 14 to be compressively secured within the
second rod member 42.
[0064] Referring again to FIG. 1, similar to first rod member 12,
the second rod member 42 preferably includes an end connector 24
attached to lower arm 50 of the second rod member 42. The end
connector 24 is used to interconnect the second rod member 42 to a
polyaxial pedicle screw 34. The end connector 24 is preferably
incorporated directly into the second rod member 42 in the form of
a receptacle 26. When located at the end of the second rod member
42, the principal advantage of the integral end connector 24 is to
shrink the profile of the configuration as a system, and thereby
reduce the length of the rod implant 10 that is longitudinally
exposed beyond the pedicle screw location. In so doing, in spinal
implant applications, the adjacent vertebra beyond the end of the
second rod member 42 is not exposed to potentially impacting a rod
section that would have previously extended longitudinally beyond
the connector location. This can reduce patient pain and increase
patient mobility. A further advantage is that the smaller profile
results in less tissue displacement in the vicinity of the end
connector 24.
[0065] The structure of the end connector 24 for the second rod
member 42 is similar to that for the first rod member 12. However,
both the upper arm 48 and lower arm 50 of the second rod member 42
include a tension link cavity 36 that is sized to accommodate the
shaft 38 of the tension link 40. Referring to FIG. 1, the tension
link cavity 36 can be seen as an opening through the top of the end
of the upper arm 48, where the tension link cavity 36 in the upper
arm 48 is aligned with the tension link cavity 36 in the lower arm
50. The pedicle screw to be connected to the second rod member 42
is preferably fitted with a tension link 40, and the tension link
shaft 38 is extended through the tension link cavity 36 in the
receptacle 26 and through the tension link cavity 36 in the upper
arm 48. A tension link nut 58 is then threaded onto the end of the
tension link shaft 38 and is tightened. The tension link nut 58
provides the tightening or clamping force for the second rod member
42, thereby deflecting the upper arm 48 toward the lower arm 50 and
securing the beam 14 within the second rod member 42.
[0066] Referring again to FIG. 1, preferably, a notch 60 is
positioned in the second rod member 42 near the distal opening 52.
For those embodiments incorporating a notch 60, the distal opening
52 next to the notch 60 is essentially a hoop structure 62 through
which the beam 14 passes to enter the interior hollow chamber 44.
The notch 60 longitudinally separates the distal opening 52 from a
second opening or interior opening 64. The interior opening 64 is
formed by an arch 66 extending from and interconnecting the upper
arm 48 to the lower arm 50.
[0067] As shown in FIGS. 1, 2 and 7, in a side elevation view, the
notch 60 may be a variety of shapes, such as an inverted U-shape,
or an inverted V-shape. Although not required, the hoop structure
62 of the distal opening 52 aligns and supports the beam 14 when it
is positioned within the interior hollow chamber 44 prior to
tightening of the second beam member 42. The hoop structure 62 of
the distal opening 52 also functions to prevent the beam 14 from
rocking up and down prior to applying a clamping or tightening
force to the second rod member 42. More particularly, the hoop
structure 62 substantially maintains the alignment of the
longitudinal axis LA.sub.b-LA.sub.b of the beam 14 with the
longitudinal axis LA.sub.c-LA.sub.c of the hollow chamber 44 of the
second rod member 42 while sliding the beam 14 into the second rod
member 42 and implanting the rod implant 10, and through such time
as a clamping or tightening force is applied to the second rod
member 42. The notch 60 also serves to lighten the second rod
member 42 by reducing its mass.
[0068] The beam 14 and the second rod member 42 work in combination
to provide an adjustable rod segment that can be shortened or
lengthened during the implant procedure by the surgeon to
accommodate the specific spacial requirements of the patient. One
particular use of the implant is to span one level (one
intervertebral disc). Referring to FIG. 2, in use, the surgeon
first inserts a first pedicle screw 34 into a first vertebra
V.sub.1 of the patient, and then inserts a second pedicle screw 34
into a second vertebra V.sub.2 of the patient. Tension links 40 are
then inserted into the enlarged areas 32 of the pedicle screws 34.
Alternately, the tension links are preloaded into the pedicle
screws before they are implanted into the vertebrae. The beam 14 is
then interconnected to the first pedicle screw 34 using a first
connector, and the second rod member 42 is interconnected to the
second pedicle screw 34 using a second connector. To perform this
step, the beam 14 is preferably loosely inserted into the second
rod member 42 in advance of interconnecting the second rod member
42 to the second pedicle screw. That is, the surgeon pre-assembles
the beam 14 of the first rod member 12 inside the second rod member
42, but does not tighten the two members together. The surgeon then
lowers both the first rod member 12 and the second rod member 42 as
a unit over the pedicle screws. Referring again to FIGS. 1 and 2,
the surgeon then preferably tightens a link nut 58 over the tension
link shaft 38 that is associated with the first rod member 12.
Again, the surgeon may then adjust the length of the beam 14 inside
the second rod member 42 by sliding the beam 14 into or out of the
clamp to obtain the proper bridge distance needed between the first
pedicle screw and the second pedicle screw. Subsequently, the
surgeon can apply a tightening force to the second rod member 42 to
secure the beam 14 within the second rod member 42. The implant 10
provides the surgeon the ability to tighten the second rod member
42 to its associated pedicle screw and also clamp the second rod
member 42 to the first rod member 12 using one effort and one
structure. This is accomplished in the preferred assembly shown in
FIGS. 1 and 2 by applying and tightening a link nut 58 to the
tension link shaft 38 of the tension link 40, which is operatively
connected to the enlarged area 32 of the pedicle screw 34
associated with the second rod member 42. This action progressively
and selectively deflects the upper arm 48 toward the lower arm 50,
thereby compressively securing the beam 14 of the first rod member
12 within the second rod member 42.
[0069] Referring now to the preferred embodiment shown in FIG. 2,
and for purposes of this description, an effective beam length
L.sub.b of beam 14 is defined as the distance from the pedicle
screw to which it is attached to the distal beam end 16. The
effective clamp length L.sub.c of second rod member 42 is defined
as the distance from the pedicle screw to which it is attached to
the distal opening 52. For the assembly shown in FIG. 2, both the
effective beam length L.sub.b and the effective clamp length
L.sub.c are shorter than the bridge distance D.sub.B, which is the
distance between the first pedicle screw and the second pedicle
screw.
[0070] Referring now to FIG. 3, rotational adjustability of the
implant 10 can be provided by using a beam 14 that is rotatable
within the interior hollow chamber 44. For example, a beam 14
having a circular cross section like that shown in FIG. 8a can be
coupled with a second rod member 42 preferably having a circular
distal opening 52 and interior hollow chamber 44. In this example,
the circular cross section of beam 14 may be rotated within the
second rod member 42, thereby allowing the surgeon the ability to
rotate and angularly adjust the position of the first rod member 12
relative to the second rod member 42. Rotational adjustability is
permitted before applying a tightening force to the second rod
member 42 and securing the beam 14 within the interior hollow
chamber 44 of the second rod member 42. FIG. 8b illustrates that
beam 14 may have a cross section resembling an oblong shape. For
this variation, the distal opening 52 and interior hollow chamber
44 are also preferably substantially oblong in shape. This
modification provides an assembly that does not allow rotation of
the first rod member 12 relative to the second rod member 42, which
may be desirable in certain situations. Of course, other
configurations are possible, such as corresponding triangular,
rectangular, and polygonal shapes (not shown). In addition, the
beam cross-section may differ from the shape of the cross-section
of the interior hollow chamber. Thus, a variety of shapes and
combination of shapes are possible for the cross section of the
beam 14 and the interior hollow chamber 44, and such possible
different shapes for the structures are within the scope of the
present invention.
[0071] Referring now to FIG. 13, the upper arm 48 of the second rod
member 42 may optionally include a recess 68 for receiving a
cooperating projection 70 positioned on the edge of the slot of the
lower arm 50. The recess 68 and projection 70 may be a variety of
shapes, and may include means for interlocking. For example, the
projection 70 may include a barb (not shown) that interlocks with
one or more ridges (not shown) within the recess 68. The position
of the recess 68 and projection 70 may be reversed such that the
recess is located on the lower arm 50 and the projection is located
on the upper arm 48.
[0072] Referring to FIGS. 1-13, the socket exterior 28 of the end
connector 24 at one or both of the first rod member 12 and second
rod member 42 may be rounded to substantially mirror the socket
interior 30 as shown in FIG. 1. Alternatively, it may be have a
different shape, such as the block shape shown in FIG. 7.
Additionally, as shown in FIG. 1, the center of the enlarged areas
32 of the polyaxial pedicle screws 34 may be substantially aligned
with the longitudinal axis of the beam 14 of the first rod member
12, and aligned with the longitudinal axis of the hollow chamber 44
of the second rod member 42, or the centers may be offset, as shown
in FIG. 7.
[0073] In general, amongst its possible uses, the rod implant 10
permits a length of rod to be adjusted at the surgical site without
having to cut the rod, or use a standardized rod length that may
not fit the patient. Furthermore, utilizing the components of the
present invention, the entire assembly can be tightened by securing
a link nut 58 at the second rod member 42. This greatly simplifies
the surgeon's efforts and serves to reduce operation time and
associated patient risk. In addition, as will be appreciated by
those skilled in the art, among its many potential uses the second
rod member 42 can be used to attach a new section of rod to an
existing section of rod, to extend a section of rod, to provide
length adjustability to a rod, to provide a means of attaching a
separate structure to the end of a new or existing rod, to provide
a means of attaching a separate structure to the end of a new or
existing rod while adjusting the length of the rod, or to reinforce
an existing section of rod.
[0074] Referring now to FIG. 14, a further embodiment of the second
rod member 42' is shown. Second rod member 42' includes a number of
structural features that are similar to the previously described
second rod member 42. That is, an interior hollow chamber 44 is
sized to receive a beam 14 of a first rod member 12, and the second
rod member 42' functions as a clamp to provide a compressive force
to secure the beam 14 of the first rod member 12 within the
interior hollow chamber 44. Second rod member 42' differs from
second rod member 42 in that it includes a deformable connector 72
that can be used to secure the second rod member 42' to a pedicle
screw, wherein the pedicle screw has a substantially straight upper
shank portion, such as a TSRH 3D pedicle screw 74 known to those
skilled in the art. More particularly, the deformable connector 72
acts as a clamp within a clamp, by providing a compressive force
around a portion of the shank 76 of a pedicle screw 74.
[0075] Referring still to FIG. 14, the deformable connector 72 is
situated within an open portion or cavity 78 of the second rod
member 42'. The upper arm 48 of the second rod member 42'
preferably includes a upper arm shoulder 80 against which a portion
of the deformable connector 72 is positioned. Similarly, the lower
arm 50 of the second rod member 42' preferably includes a lower arm
shoulder 82, also against which a portion of the deformable
connector 72 is positioned. In addition, the second rod member 42'
includes a tightening member 84 that serves as a means for
tightening the second rod member 42' such that the second rod
member 42' compresses and acts as a clamp to hold the beam 14 of
the first rod member 12 secure.
[0076] In one preferred embodiment, tightening member 84 is a screw
or bolt positioned on a substantially opposing side of the
deformable connector 72 relative to the positions of the upper arm
shoulder 80 and the lower arm shoulder 82. That is, the tightening
member 84 is preferably on one side of the shank 76 of the pedicle
screw 74, and the upper arm shoulder 80 and the lower arm shoulder
82 are on situated on an opposing side of the shank 76 of the
pedicle screw 74. When tightened, the tightening member 84 not only
draws the upper arm 48 and the lower arm 50 together, thereby
compressing the second rod member 42', but also necessarily shrinks
the size of the cavity 78 and consequently confines the deformable
connector 72 between the upper arm shoulder 80, the lower arm
shoulder 82 and a shank 86 of the tightening member 84. When fully
tightened, the tightening member 84 puts at least a first point 90
of the perimeter 92 of the deformable connector 72 in contact with
the upper arm shoulder 80. In addition, when fully tightened, the
tightening member 84 puts at least a second point 94 of the
perimeter 92 of the deformable connector 72 in contact with the
lower arm shoulder 82. In addition, the shank 86 of the tightening
member 84 contacts at least a third point 96 on the perimeter 92 of
the deformable connector 72. These at least three points 90, 94,
and 96 compress the deformable connector 72 such that it securely
holds the shank 76 of the pedicle screw 74. Preferably, at least
one of the upper arm shoulder 80 and the lower arm shoulder 82 are
not parallel to a side surface 88 of the shank 76 of the pedicle
screw 74.
[0077] Referring now to FIG. 15, the deformable connector 72 may
also be adapted for use in a first rod member 12', wherein the
first rod member 12' includes a beam 14 that is connected to a
pedicle screw 74 by way of the deformable connector 72 that is
situated within a cavity 78 of the first rod member 12'. Here, the
deformable connector 72 is again confined within the first rod
member 12' by a upper arm shoulder 80 and lower arm shoulder 82,
and further by the shank 86 of the tightening member 84.
[0078] Referring to FIGS. 14 and 15, one advantage to a
substantially cylindrical-shaped deformable connector 72 is that it
can be rotated within the cavity 78 prior to tightening to
accommodate the position of the pedicle screw 74. Therefore, second
rod member 42' with deformable connector 72 overcomes the problem
of where the pedicle screw 74 is not aligned sufficiently
perpendicular to the intend rod axis. A substantially
cylindrical-shaped deformable connector 72 can be rotated within
the cavity 78 and then slipped over the shank 76 of the pedicle
screw 74, and subsequently secured within the second rod member 42'
by tightening the tightening member 84. Thus, deformable connector
72 in combination with a clamping style first rod member 12' or
second rod member 42' is rotatably adjustable prior to tightening.
Rotation arrows A.sub.3 illustrate that the deformable connector 72
is rotatable within the cavity 78. This allows a surgeon to
accommodate a patient's particular needs during the surgical
procedure.
[0079] For the devices shown in FIGS. 14 and 15, and assuming that
at least one of either first rod member 12' or second rod member
42' is being used, in use, a surgeon first installs a bone screw
for general applications, or a pedicle screw if the device is to be
interconnected to the pedicle of a vertebra. Assuming the device is
used in an assembly for bridging an intervertebral disc, a second
pedicle screw is attached to the other vertebra, or an existing
second pedicle screw is used. Alternatively, the device could be
used where two existing pedicle screws were already in place. The
surgeon then preferably inserts the beam of the first rod member
into the second rod member. Subsequently, the surgeon preferably
lowers the first rod member and second rod member as a unit over
the pedicle screws. The shank 76 of the pedicle screw 74 associated
with first rod member 12' or second rod member 42' is slipped into
the passageway 98 of the deformable connector 72 that is positioned
in the cavity 78 of the respective first rod member 12' or second
rod member 42'. The deformable connector 72 is rotated as desired
by the surgeon to obtain the proper alignment in order to slip the
first rod member 12' or second rod member 42' over the pedicle
screw 74. If first rod member 12' is being used, then the surgeon
tightens first rod member 12' to its pedicle screw by advancing the
tightening member 84 associated with the first rod member 12'. If
first rod member 12' is not being used, then the rod member
opposite the second rod member 42' is preferably otherwise secured
to its pedicle screw. Subsequently, after adjusting the length of
the beam 14 within the second rod member, the second rod member is
then secured to the first rod member. If second rod member 42' is
being used, then the securing step is accomplished by advancing the
tightening member 84 associated with the second rod member 42'.
[0080] Referring now to FIGS. 16-19, in one preferred embodiment,
the deformable connector 72 is substantially cylindrical in shape,
and this shape allows the cylindrical deformable connector 72 to
rotate within the cavity 78 of the second rod member 42'. The
deformable connector 72 includes a passageway 98 for receiving the
shank 76 of the pedicle screw 74. More particularly, the passageway
98 is an opening through the deformable connector 72 that is sized
to accommodate the shank 76 of a pedicle screw 74. In addition, the
deformable connector 72 has a composition or structure allowing the
deformable connector 72 to compress around the shank 76 of the
pedicle screw 74 upon tightening of the second rod member 42'. More
particularly, as shown in FIG. 16a, the deformable connector 72 may
be made of a type of material that can be compressed, such as a
suitable resilient material. In use, upon tightening the tightening
member 84, the deformable connector 72 is squeezed and compressed
between the upper arm shoulder 80, lower arm shoulder 82 and the
shank 86 of the tightening member 84 such that the shank 76 of the
pedicle screw 74 is secured within the deformable connector 72,
which in turn, is secured within the second rod member 42'.
[0081] Alternatively, as shown in FIGS. 16b, 17, and 18, in a
preferred embodiment, the deformable connector 72 may include a
slit or groove 100 along a side that preferably intercepts the
passageway 98. The groove includes a first edge 102 and an opposing
and separated second edge 104. In use, upon tightening the
tightening member 84, the deformable connector 72 is squeezed and
compressed between the upper arm shoulder 80, lower arm shoulder 82
and the shank 86 of the tightening member 84. The first edge 102 of
the groove 100 is moved in a direction of arrow A.sub.4 toward the
second edge 104, which is being moved in a direction of arrow
A.sub.5 toward first edge 102. As a result of the tightening force,
the groove 100 allows the passageway 98 of deformable connector 72
to collapse around the shank 76 of the pedicle screw 74, such that
the pedicle screw 74 is secured within the deformable connector 72,
which in turn, is secured within the second rod member 42'.
[0082] The deformable connector 72 is anticipated to have a
diameter of approximately 10 to 13 mm, and the passageway 98 within
the deformable connector 72 is anticipated to have a diameter just
slightly larger than the diameter of the shank 76 of a pedicle
screw 74, which is typically on the order of about 5.2 mm in
size.
[0083] Referring now to FIG. 19, for the case of a substantially
cylindrical-shaped deformable connector 72, portions of the
deformable connector 72 may be truncated to reduce the weight and
displacement volume of the deformable connector 72. For example, a
truncated first end 106 and/or a truncated second end 108 of the
deformable connector 72 can be flattened or otherwise modified in
shape. Preferably, the truncated first end 106 and truncated second
end 108 are located at the passageway openings 110 and 112,
respectively.
[0084] Referring now to FIGS. 20 and 21, the deformable connector
72 may also take the form of a bead or sphere. A sphere-shaped
deformable connector 72 allows the deformable connector 72 to be
rotated in a multitude of directions to accommodate alignment with
the shank 76 of a pedicle screw 74.
[0085] Referring now to FIG. 22, in a separate aspect of the
invention, an interference fit connector 114 is presented. For
purposes of illustration, a second rod member 42' is shown in
combination with a first rod member 12'', wherein first rod member
12'' incorporates an interference fit connector 114. For the
embodiment shown in FIG. 22, the interference fit connector 114 is
integrally attached to the beam 14. More particularly, the
proximate beam end 18 of first rod member 12'' is attached to an
interference fit connector 114.
[0086] Referring now to FIGS. 22-25, interference fit connector 114
has a C-shaped section 116 having a slot 118 separating an upper
section 120 from a lower section 122. The first rod member 12''
includes a first aperture 124 through the upper section 120, and a
second aperture 126 through the lower section 122. In addition, the
C-shaped section 116 includes an interference tightening member
128, which serves as a means for tightening the C-shaped section
116 and drawing the upper section 120 and the lower section 122 in
closer proximity relative to each other, such that the shank 76 of
pedicle screw 74 is pinched or clamped within the C-shaped section
116 and secured to the first rod member 12''. As shown in FIGS. 22
and 24, the interference tightening member 128, or means for
tightening the C-shaped section 116, can preferably take the form
of a screw or a bolt. However, a band clamp, such as a worm-gear
band could also be used to compress the upper section 120 and lower
section 122 toward each other. Accordingly, a number of means for
tightening the C-shaped section 116 are possible and are within the
scope of the present invention.
[0087] One advantage of the C-shaped section 116 is that, when used
in a first rod member 12'', it provides a rod and connector
combination that is relatively easy for the surgeon to use. A
second advantage is that it limits the length of the connector and
implant structure that is longitudinally exposed beyond the pedicle
screw 74 location. In so doing, in spinal implant applications, the
adjacent vertebra beyond the end of the first rod member 12'' is
not exposed to potentially impacting a rod section that would have
previously extended longitudinally beyond the connector location.
This can reduce patient pain and increase patient mobility. A
further advantage is that the smaller profile results in less
tissue displacement in the vicinity of C-shaped section 116.
[0088] Referring now to FIG. 26, a modified version of the device
shown in FIG. 24 is presented. The first rod member 12''' shown in
FIG. 26 incorporates an integral connector that uses an
interference fit, but has a reverse orientation as compared to the
device shown in FIG. 24. More specifically, the proximate end 18 of
first rod member 12''' includes a reverse C-shaped section 130
having a slot 118 separating an upper section 120 from a lower
section 122. The first rod member 12''' includes a first aperture
124 through the upper section 120 and a second aperture 126 through
the lower section 122. In addition, the reverse C-shaped section
130 includes an interference tightening member 128, which serves as
a means for tightening the reverse C-shaped section 130 and drawing
the upper section 120 and the lower section 122 in closer position
relative to each other, such that the shank 76 of pedicle screw 74
is clamped or pinched within the reverse C-shaped section 130 and
secured to the first rod member 12'''. As shown in FIG. 26, the
interference tightening member 128, or means for tightening the
reverse C-shaped section 130, can preferably take the form of a
screw or a bolt. However, a band clamp, such as a worm-gear band
could also be used to compress the upper section 120 and lower
section 122 toward each other. Accordingly, a number of means for
tightening the C-shaped section 130 are possible and are within the
scope of the present invention.
[0089] One advantage of the reverse C-shaped section 130 is that,
when used in a first rod member 12''', it provides a rod and
connector combination that is relatively easy for the surgeon to
use. A second advantage is that it provides an interference type of
connector fitting where the tightening member 128 is positioned on
the opposite side of the pedicle screw 74 as that of the rod
portion. Therefore, one potential use is for short bridge
distances; that is, where the distance between pedicle screws is
relatively small, and does not lend itself to placing the
tightening member 128 in a position between the pedicle screws
being spanned.
[0090] In use, a surgeon first installs a pedicle screw, or
otherwise identifies an existing bone screw that the interference
fit connector is to be attached to. Depending upon the choice of
the device by the surgeon, the surgeon then slips the C-shaped
section 116 or the reverse C-shaped section 130 over the shank 76
of the pedicle screw 74. To tighten the type C-shaped section 116
or the reverse C-shaped section 130 to the pedicle screw 74, the
surgeon advances the tightening member 128. If a screw or bolt is
used as a tightening member 128, this last step comprises advancing
the screw or bolt until the C-shaped section 116 or the reverse
C-shaped section 130 is secured to the shank 76 of the pedicle
screw 74.
[0091] An interference fit connector can also be oriented at any
angle relative to the beam that is between the pedicle screws. More
particularly, FIG. 26 illustrates a reverse C-shaped section 130
that is situated at an angle of about 180 degrees relative to the
C-shaped section 116 shown in FIG. 24. That is, it is not on the
same side as the beam 14, but instead, it is on the opposite side
of the pedicle screw relative to the beam 14. However, the C-shaped
connector could be oriented at any angle, such as 30, 45, 60, 90,
135, etc. degrees (not shown) relative to the beam 14 to which it
is attached. These different orientations for the C-shaped
connector may be preferred depending upon a patient's needs, for
example, because of an injury that makes such an orientation
preferable.
[0092] Referring now to FIG. 27, an implant assembly is shown in
plan view that includes two pedicle screws with an interference fit
type of integral connector such as first rod member 12'' shown on
the left side, and a second rod member 42'' with a deformable
connector 72 shown on the right side. However, the deformable
connector 72 of FIG. 27 includes a modified shape in the form of an
indentation 132 that cooperates with the tightening member 84. The
indentation 132 in the deformable connector 72 extends down the
side of the deformable connector 72. The indentation 132 allows the
distance d.sub.2 between the right-most pedicle screw 74 and the
right-most tightening member 84 to be reduced relative to the
distance d.sub.1 between the right-most pedicle screw 74 and the
right-most tightening member 84 as shown in FIG. 23. Said
differently, distance d.sub.1 of FIG. 23 is less than distance
d.sub.2 of FIG. 27. This can be further reduced by using a screw as
a tightening member 84 that has no upper flange. As a result of the
indentation 132 feature, the distance d.sub.3 of the length of the
second rod member 42'' between the right-most pedicle screw 74 and
the right-most end of the second rod member 42'' is also reduced
relative to the distance d.sub.4 of the length of the second rod
member 42' between the right-most pedicle screw 74 and the
right-most end of the second rod member 42', as shown in FIG. 23.
For spinal implants, the adjacent vertebra beyond the end of the
second rod member 42'' is not exposed to potentially impacting a
rod section that would have previously extended longitudinally
beyond pedicle screw location. This can reduce patient pain and
increase patient mobility. A further advantage is that the smaller
profile results in less tissue displacement in the vicinity of
second rod member 42''.
[0093] Yet a separate aspect of the present invention is that
different possible assemblies are available to meet a particular
patient's needs. Referring now to FIG. 28, an implant assembly is
shown that includes first rod member 12 in combination with a
second rod member 42'. This combination allows for a polyaxial
pedicle screw 34 to be used with a pedicle screw having a straight
upper shank portion, such as pedicle screw 74 that is shown on the
right side of the figure.
[0094] Referring now to FIG. 29, a modified deformable connector
72' is shown wherein the deformable connector 72' has a
skeletonized structure to reduce its weight. As shown in FIG. 29,
in a preferred embodiment, the skeletonized structure of the
deformable connector 72' can take the form of one or more tie beams
134 that structurally tie together portions of the deformable
connector 72'. The tie beam 134 may include a textured surface 136
with, for example, a ridged, grooved or roughened surface for
allowing the tie beam 134 to be selectively adjusted during the
tightening process. The deformable connector 72' can be formed of a
structural frame that is partially compressible to lock the pedicle
screw 74 in place and prevent its rotation after a tightening force
is applied using a tightening member 84.
[0095] The exterior surface of the beam 14, such as the top side 20
and the bottom side 22 may possess surface features that interlock
and aid in securing the beam 14 to the inside of the second rod
member 42. Similarly, the inside surfaces of the second rod member
42, 42' and/or 42'', such as the interior surfaces 54 and/or 56 of
the upper arm 48 and lower arm 50, respectively, may also include
features that interlock and aid in securing the beam 14 within the
second rod member 42. For example, the various previously
identified surfaces may include detents or depressions that
receivingly accept other structural features. Surficial features
may include texturing, ridges, bumps, projections, protrusions,
indentations, adhesives, and coverings or coatings of alternate
materials. In addition, although not required, at least one set
screw could be used to interlock the beam 14 to the second rod
member 42, 42' and/or 42''.
[0096] In a separate aspect of the invention, although the second
rod members 42, 42', and 42'' are preferably a one-piece,
monolithic structure, they may be manufactured, assembled, or
implanted in plurality of pieces. By way of example and not
limitation, a multi-piece second rod member 42, 42', and 42'' can
include an upper arm 48 separately and/or hingedly connected to the
lower arm 50. Such a structure may be desirable to allow easy
insertion of a deformable connector 72 or 72' within a cavity 78 of
a second rod member 42' and 42'' during the manufacturing
process.
[0097] The devices and structural features described herein are
made from a material that possesses the appropriate strength
characteristics necessary to withstand loading from the human body
when used in medical applications. Tensile strength qualities of
the materials used is a key consideration. Preferably, materials
may include ceramics, plastics, metals, or carbon fiber composites.
More preferably, the materials are made from titanium, a titanium
alloy, or stainless steel.
[0098] Devices disclosed herein can also be made of thermal memory
materials or materials that possess different elastic properties at
varying temperatures. In this aspect of the invention, the subject
component(s) may be heated or cooled to a desired temperature,
implanted, then subsequently allowed to cool or warm to the
temperature of the ambient conditions that will exist during the
usage period for the subject device, namely, normal body
temperature.
[0099] The dimensions of the devices disclosed herein are expected
to vary depending upon the patient's needs. For example, a rod the
entire length of the spine, such as 2 feet in length, may be used.
Alternately, a rod only 10 to 40 mm long may be all that is
necessary to span and bridge a disc of the spine. Therefore, for
spinal applications, the preferable length of rod is simply an
adequate length to bridge the necessary vertebral disc or discs. As
a separate example, the beams of the first rod members described
herein are anticipated to have a diameter of about 3-7 mm if solid
and circular in cross section, and on the order of about 4-7 mm in
length in the long dimension if solid and oblong in cross section.
Again, the size of the dimensions of the devices is subject to the
material used to construct the subject device, the intend use, and
the specific characteristics of the patient. For example, a large
person may have larger sized components than a device implanted in
a child.
[0100] The curvature of the rod may also be variable depending upon
the desired final curvature sought for the patient. The curvature
may be established during manufacture of a given rod, and/or a
given rod segment may have its curvature adjusted at the of time
surgery prior to implantation.
[0101] The devices disclosed herein also have application to uses
other than those specifically discussed. For example, one or more
of the devices described herein have application to uses outside of
surgical stabilization. For example, the devices could be used to
connect framing of objects such as furniture. Even within the field
of medicine and spinal surgery, one anticipated use involves using
certain components described herein to cross-link or structurally
interconnect right and left stabilization assemblies that are
implanted on either side of a spinous process.
[0102] While various embodiments of the present invention have been
described in detail, it is apparent that modifications and
adaptations of those embodiments will occur to those skilled in the
art. However, it is to be expressly understood that such
modifications and adaptations are within the spirit and scope of
the present invention, as set forth in the following claims.
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