U.S. patent application number 13/970346 was filed with the patent office on 2014-07-17 for posterior fixation system.
This patent application is currently assigned to WARSAW ORTHOPEDIC, INC.. The applicant listed for this patent is Robert A. Farris, Kevin T. Foley, Stephen M. Papadopoulos, Jeffrey W. Poyner, Ricardo Sasso. Invention is credited to Robert A. Farris, Kevin T. Foley, Stephen M. Papadopoulos, Jeffrey W. Poyner, Ricardo Sasso.
Application Number | 20140200617 13/970346 |
Document ID | / |
Family ID | 42668255 |
Filed Date | 2014-07-17 |
United States Patent
Application |
20140200617 |
Kind Code |
A1 |
Farris; Robert A. ; et
al. |
July 17, 2014 |
Posterior Fixation System
Abstract
A posterior fixation system includes a saddle member, an
anchoring member, an occipital plate, an occipital rod, and a
cross-link connector. The anchoring member anchors the saddle
member to bone. The saddle member includes a channel that is
adapted to receive an orthopedic rod. The saddle member and the
anchoring member can be coupled so as to allow multi-axial movement
of the members. Connection of individual rods can be accomplished
by connecting the rods with the cross-link connector. The occipital
plate secures the rods to the occipital bone of the skull.
Alternatively, the occipital rod can be secured to the occipital
bone.
Inventors: |
Farris; Robert A.; (Cordova,
TN) ; Foley; Kevin T.; (Germantown, TN) ;
Papadopoulos; Stephen M.; (Ann Arbor, MI) ; Poyner;
Jeffrey W.; (Atoka, TN) ; Sasso; Ricardo;
(Carmel, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Farris; Robert A.
Foley; Kevin T.
Papadopoulos; Stephen M.
Poyner; Jeffrey W.
Sasso; Ricardo |
Cordova
Germantown
Ann Arbor
Atoka
Carmel |
TN
TN
MI
TN
IN |
US
US
US
US
US |
|
|
Assignee: |
WARSAW ORTHOPEDIC, INC.
Warsaw
IN
|
Family ID: |
42668255 |
Appl. No.: |
13/970346 |
Filed: |
August 19, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12715049 |
Mar 1, 2010 |
8512380 |
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13970346 |
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|
10230781 |
Aug 28, 2002 |
7699872 |
|
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12715049 |
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09663638 |
Sep 15, 2000 |
6485491 |
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10230781 |
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Current U.S.
Class: |
606/278 |
Current CPC
Class: |
A61B 17/7037 20130101;
A61B 17/701 20130101; A61B 17/7041 20130101; A61B 17/7032 20130101;
A61B 17/7056 20130101; A61B 17/7055 20130101; A61B 17/7004
20130101; A61B 17/7049 20130101 |
Class at
Publication: |
606/278 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Claims
1. A multi-axial bone attachment assembly, comprising: a saddle
member having a plurality of upright portions that define a channel
through said saddle member, said saddle member further having a
hole therethrough bounded by an inner wall, said hole forming a
lower opening in said saddle member; a bone anchoring member
extending through said opening, said bone anchoring member
including a head portion and an anchoring portion; and a washer
having a recessed portion for accommodating an orthopedic rod and a
radially extending projection, said washer being fitted within said
hole of said saddle member and atop said bone anchoring member.
2. The assembly of claim 1, wherein said inner wall includes a
groove, and said assembly further comprises a snap-ring fitted in
said groove and over said washer to hold said washer in said hole
of said saddle member.
3. The assembly of claim 2, wherein said upright portions include
threaded portions, and said assembly further comprises a threaded
member for engagement with said threaded portions.
4. The assembly of claim 3, wherein said upright portions are
internally threaded, and said threaded member is an externally
threaded set screw.
5. The assembly of claim 4, wherein said set screw includes an
upper surface that is convexly rounded.
6. The assembly of claim 3, wherein said threaded portions have
reverse angle threads.
7. The assembly of claim 1, wherein said washer includes an upper
portion and a lower portion, said recessed portion being a part of
said upper portion and said projection being a part of said lower
portion.
8. The assembly of claim 7, wherein said inner wall includes a
groove, and said assembly further comprises a snap-ring fitted in
said groove and over said lower portion of said washer to hold said
washer in said hole of said saddle member.
9. The assembly of claim 7, wherein said upper portion of said
washer includes a plurality of recessed portions.
10. The assembly of claim 7, wherein said lower portion of said
washer includes a plurality of projections.
11. The assembly of claim 1, wherein said upright portions include
threaded portions, and said assembly further comprises a threaded
member for engagement with said threaded portions.
12. The assembly of claim 1, wherein said anchoring member is a
bone screw.
13. The assembly of claim 12, wherein said bone screw includes a
head portion having a convex underside.
14. The assembly of claim 13, wherein said convex underside is
spherical.
15. The assembly of claim 14, wherein said bone screw includes a
portion having a thread with a load flank and a root surface, and
the angle between said load flank and said root surface is
acute.
16. The assembly of claim 15, wherein said angle is about 86
degrees.
17. The assembly of claim 1, wherein said anchoring member is a
hook member.
18. The assembly of claim 17, wherein said anchoring portion
includes a curved portion connected to said head portion and a
straight portion connected to said curved portion, said head
portion including a plurality of spherical portions for coupling
said anchoring member to said saddle member.
19. The assembly of claim 1, wherein said upright portions each
have a trough defined therein, said washer including a plurality of
projections with each provided in one of said troughs.
20. The assembly of claim 1, wherein said lower opening includes a
concave wall portion and a conical wall portion for allowing
angular movement of said bone anchoring member.
21. A spinal implant system, comprising: a saddle member having a
plurality of upright portions that define a channel through said
saddle member, said saddle member further having a transverse hole
defined through said upright portions that is transverse with
respect to said channel; a bone anchoring member coupled to said
saddle member for anchoring said saddle member to bone; and an
offset member adapted to couple to an orthopedic rod, said offset
member having a body adapted to couple to said rod and a coupling
member extending from said body through said transverse hole in
said upright portions.
22. The system of claim 21, wherein said upright portions include
threaded portions, and said system further comprises a threaded
member for engagement with said threaded portions.
23. The system of claim 22, wherein said upright portions are
internally threaded, and said threaded member includes an
externally threaded set screw.
24. The system of claim 22, wherein said threaded portions have
reverse angle threads.
25. The system of claim 21, wherein said anchoring member includes
a hook member.
26. The system of claim 21, wherein said offset member includes a
rod receiving channel defined in said body for receiving said
rod.
27. The system of claim 26, wherein said offset member includes a
threaded bore intersecting said rod receiving channel and a
threaded set screw provided in said threaded bore.
28. The system of claim 26, further comprising a slot defined in
said rod receiving channel.
29. The system of claim 21, wherein said body includes a pair of
body members that define a channel in said body for receiving said
rod.
30. The system of claim 29, wherein said offset member has a
longitudinal axis extending along said coupling member, and said
body members extend parallel to said longitudinal axis.
31. The system of claim 29, wherein said offset member has a
longitudinal axis extending along said coupling member, and said
body members extend perpendicular to said longitudinal axis.
32. The system of claim 29, wherein one of said body members has a
threaded bore defined therein and a threaded set screw provided in
said threaded bore.
33. The system of claim 21, further comprising a washer having a
recessed portion adapted to accommodate said orthopedic rod and a
radially extending projection, said washer being fitted within said
saddle member.
34. The system of claim 33, further comprising a snap ring provided
in said saddle for securing said washer in said saddle member.
35. The system of claim 21, further comprising said orthopedic rod
coupled to said offset member.
36. The system of claim 35, wherein said orthopedic rod includes an
occipital rod.
37. The system of claim 35, further comprising an occipital plate
coupled to said rod, said plate including: a cross-shaped member
having a longitudinal axis connecting first and second longitudinal
ends and a transverse axis connecting first and second transverse
ends, said cross-shaped member having a plurality of apertures
therethrough; and a plate saddle member coupled to said
cross-shaped member, said plate saddle member having a plurality of
upright portions that define a channel through said plate saddle
member, wherein said rod is coupled in said channel.
38. The system of claim 37, further comprising a cross-link
connector having a pair of coupling ends each adapted to couple to
a rod and a cylindrical member provided between said coupling ends,
one of said coupling ends being coupled to said rod.
39. An orthopedic fixation plate, comprising: a cross-shaped member
having a longitudinal axis connecting first and second longitudinal
ends and a transverse axis connecting first and second transverse
ends, said cross-shaped member having a plurality of apertures
therethrough; and a saddle member coupled to said cross-shaped
member, said saddle member having a plurality of upright portions
that define a channel through said saddle member.
40. The plate of claim 39, wherein said plate includes a plurality
of saddle members attached to said cross-shaped member, each of
said saddle members having a plurality of upright portions that
define respective channels through said saddle members.
41. The plate of claim 39, wherein said saddle member is integral
with said cross-member.
42. The plate of claim 39, wherein said saddle member is pivotally
coupled to said cross-member.
43. The plate of claim 39, wherein said saddle member is located at
one of said first and second longitudinal ends.
44. The plate of claim 39, wherein said channel of said saddle
member has an axis, and said channel axis is substantially
perpendicular to said longitudinal axis of said cross-shaped
member.
45. The plate of claim 39, wherein said cross-member has at least
one of said apertures at each of said first and second transverse
ends of said cross-member.
46. The plate of claim 39, wherein said apertures are bounded by a
surface having a conical portion.
47. The plate of claim 46, wherein said surface has an upper
conical portion and a lower conical portion.
48. The plate of claim 39, wherein said cross-shaped member is
curved.
49. The plate of claim 39, wherein said cross-shaped member is
curved so that said longitudinal axis has a curved portion and said
transverse axis is substantially straight.
50. A cross-link connector, comprising: a plurality of coupling
ends each adapted to couple to an orthopedic rod; and a cylindrical
member integrally connected to said coupling ends, said cylindrical
member having a cylindrical shape for permitting multi-axial
bending of said cylindrical member.
51. The cross-link connector of claim 50, wherein each of said
coupling ends includes a curved member that defines a cavity
adapted to receive said rod.
52. The cross-link connector of claim 51, wherein each of said
coupling ends includes a threaded bore and a set screw received in
said bore for securing said rod.
53. The cross-link connector of claim 50, wherein said cylindrical
member is arched between said coupling ends.
54. A multi-axial bone attachment assembly, comprising: a saddle
member having a plurality of upright portions that define a channel
through said saddle member, said saddle member further having a
hole therethrough bounded by an inner wall, said hole forming a
lower opening in said saddle member; a bone anchoring member
extending through said opening, said bone anchoring member
including a coupling portion provided in said hole for permitting
multi-axial movement of said anchoring member and an anchoring
portion; and an expansion member coupled to said anchoring member
for expanding said coupling portion to lock said anchoring member
into position.
55. The assembly of claim 54, wherein said anchoring portion
includes a hook member.
56. The assembly of claim 54, wherein said coupling portion has a
substantially spherical shape.
57. The assembly of claim 54, wherein said coupling portion
includes a plurality of part spherical members.
58. The assembly of claim 57, wherein said expansion member is
coupled to said anchoring member between said part spherical
members.
59. The assembly of claim 54, wherein said expansion member
includes a set screw.
60. The assembly of claim 54, wherein said expansion member
includes a tool engaging portion, a threaded portion engaged with
said coupling member, and a conically shaped expansion portion
provided between said tool engaging portion and said threaded
portion.
61. The assembly of claim 54, wherein said upright portions include
threaded portions, and said assembly further comprises a threaded
member for engagement with said threaded portions.
62. The assembly of claim 61, wherein said threaded portions have
reverse angle threads.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention generally relates to orthopedic
implants used for correction of spinal injuries or deformities, and
more specifically, but not exclusively, concerns apparatuses for
fixing a portion of the spine, such as the cervical spine, to allow
correction or healing thereof.
[0002] In the realm of orthopedic surgery, it is well known to use
implants to fix the position of bones. In this way, the healing of
a broken bone can be promoted, and malformations or other injuries
can be corrected. For example, in the field of spinal surgery, it
is well known to place such implants into vertebrae for a number of
reasons, including (a) correcting an abnormal curvature of the
spine, including a scoliotic curvature, (b) to maintain appropriate
spacing and provide support to broken or otherwise injured
vertebrae, and (c) perform other therapies on the spinal
column.
[0003] Typical implant systems include several pieces, which
commonly are useful and may be associated with only specific other
pieces. Bone screws, hooks, and clamps are well know as fixation
devices, which are connected or adjoined to a particular bone as a
connection between the remainder of the implant and the bone.
Specially formed plates or rods are commonly used as stabilization
and support members. Thus, in a common spinal implant system, a
spinal plate is implanted along one or more vertebrae by driving a
bone screw through the plate and into each of two vertebrae. The
vertebrae are thus supported and kept in a particular position by
the plate, so as to promote healing. One example of such an
instrumentation system is U.S. Pat. No. 5,735,853 to Olerud.
[0004] Alternatively, a rod can be used as the support and
stabilizing member. In such an implant, a series of two or more
screws are inserted into two or more vertebrae to be instrumented.
A rod is then placed within or coupled to the heads of the screws,
or is placed within a connecting device that links the rod and a
screw head, and the connections are tightened. In this way, a rigid
supporting structure is fixed to the vertebrae, with the rod
providing the support that promotes correction of the vertebral
malformation or injury.
[0005] Many varieties of bone fixation devices (e.g. screws and
hooks) are monoaxial in construction. That is, such devices are
connected to the rod or plate such that a longitudinal axis through
the rod or plate and a longitudinal axis through the fixation
device are capable of only a single position with respect to each
other. While useful in certain circumstances, in many therapeutic
situations the degree of precision required to use such an
inflexible device is impractical, or can lead to a longer duration
of surgery, potentially awkward angles for the surgeon and for the
patient, with the potential for attendant complications such as
pain and/or extended rehabilitation.
[0006] More recently, bone fixation devices having multi-axial
capability have been introduced. Examples of such constructs are
shown in U.S. Pat. Nos. 5,797,911, 5,954,725, and 5,810,818. These
devices help to reduce the required precision of placement of the
fixation device, since a head portion of the fixation device is
multi-axially positionable around the bone-threaded or hook
portion. The head can thus be positioned so as to easily receive
the rod, limiting or removing much of the positioning difficulty
inherent in prior devices.
[0007] Most such devices are designed for spinal fixation at the
thoracic and lumbar levels. Accordingly, there is a need in the art
for a comprehensive multi-axial spinal implant system, and
particularly one that is useful in the cervical region of the
spine.
SUMMARY OF THE INVENTION
[0008] One form of the present invention is a unique multi-axial
bone attachment assembly. Other forms concern a unique spinal
implant system, a unique orthopedic fixation plate, a unique
cross-link connector, and another unique multi-axial bone
attachment assembly.
[0009] A further form of the present invention is directed to a
unique multi-axial bone attachment assembly that includes a saddle
member, a bone anchoring member, and a washer (crown member). The
saddle member has a plurality of upright portions that define a
channel through the saddle member. The saddle member further has a
hole therethrough bounded by an inner wall, and the hole forms a
lower opening in the saddle member. The bone-anchoring member
extends through the opening. The bone-anchoring member includes a
head portion and an anchoring portion. The washer has a recessed
portion for accommodating an orthopedic rod and may include a
radially extending projection. The washer is fitted within the hole
of the saddle member and atop the bone-anchoring member.
[0010] Yet another form concerns a unique spinal implant system. A
saddle member has a plurality of upright portions that define a
channel through the saddle member. The saddle member further has a
transverse hole defined through the upright portions that is
transverse with respect to the channel. A bone-anchoring member is
coupled to the saddle member for anchoring the saddle member to
bone. An offset member is adapted to couple to an orthopedic rod,
and the offset member has a coupling member and a body adapted to
couple to the rod. The coupling member extends from the body and
through the transverse hole of the upright members.
[0011] Another form is directed to a unique cross-shaped orthopedic
plate. The plate includes a cross-shaped member. The cross-shaped
member has a longitudinal axis connecting first and second
longitudinal ends and a transverse axis connecting first and second
transverse ends. The cross-shaped member has a plurality of
apertures therethrough. At least one saddle member is attached to
the cross-shaped member, and the saddle member has a plurality of
upright portions that define a channel through the saddle
member.
[0012] A further form concerns a unique cross-link connector. The
connector includes a plurality of coupling ends each adapted to
couple to an orthopedic rod. A cylindrical member is integrally
connected to the coupling ends. The cylindrical member has a
cylindrical shape for permitting multi-axial bending of the
cylindrical member.
[0013] Still yet another form is directed to a unique multi-axial
bone attachment assembly. A saddle member has a plurality of
upright portions that define a channel through the saddle member.
The saddle member further has a hole therethrough bounded by an
inner wall, and the hole forms a lower opening in the saddle
member. A bone-anchoring member extends through the opening. The
bone-anchoring member includes a coupling portion provided in the
hole for permitting multi-axial movement of the anchoring member
and an anchoring portion. An expansion member is coupled to the
anchoring member for expanding the coupling portion in order to
lock the anchoring member into position.
[0014] The present invention provides a modular fixation system
that allows a surgeon multiple treatment options for patients,
allowing the surgeon to adapt the treatment to specific patient
anatomy. The concepts surrounding the present invention are
specifically designed for cervical vertebral fixation, but could be
extended to include thoracic, lumbar and sacral fixation. Other
advantages and objects of the present invention will be evident in
view of the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 shows a partial cross-sectional view of a bone anchor
assembly according to one embodiment of the present invention.
[0016] FIG. 2 shows a side view of a saddle member according to the
embodiment shown in FIG. 1.
[0017] FIG. 3 shows a cross-sectional view of the saddle member
taken along line III-III in FIG. 2.
[0018] FIG. 4 shows a top view of the saddle member of FIG. 2.
[0019] FIG. 5 shows an enlarged cross-sectional view of the saddle
member taken along line V-V in FIG. 3.
[0020] FIG. 6 shows a side view of an anchor member according to
one embodiment.
[0021] FIG. 6a shows a side view of an anchor member according to
another embodiment.
[0022] FIG. 7 shows an enlarged cross-sectional view of threads of
the embodiment of the anchor member shown in FIG. 6.
[0023] FIG. 8 shows a top view of the anchor member of FIG. 6.
[0024] FIG. 9 shows a perspective view of a washer according to one
embodiment of the present invention.
[0025] FIG. 10 shows a top view of the washer of FIG. 9.
[0026] FIG. 11 shows a cross-sectional view of the washer of FIG.
9
[0027] FIG. 12 shows a top view of another embodiment of a washer
according to the present invention.
[0028] FIG. 13 shows a side view of a set screw according to one
embodiment of the present invention.
[0029] FIG. 14 shows a top view of the set screw of FIG. 13.
[0030] FIG. 15 shows a side view of a set screw according to
another embodiment of the present invention.
[0031] FIG. 16 shows a top view of the set screw of FIG. 15.
[0032] FIG. 17 shows a perspective view of a snap ring for use in
the present invention.
[0033] FIG. 17a shows a side view of an alternative embodiment of a
snap ring for use in the present invention.
[0034] FIG. 18 shows a top view of the snap ring of FIG. 17.
[0035] FIG. 19 shows a top view of an orthopedic plate according to
one embodiment.
[0036] FIG. 20 shows a side view of the orthopedic plate of FIG.
19.
[0037] FIG. 21 shows a cross-sectional view of the orthopedic plate
taken along line XXI-XXI in FIG. 19.
[0038] FIG. 22 shows a cross-sectional view of a portion of the
orthopedic plate taken along line XXII-XXII in FIG. 19.
[0039] FIG. 23 shows a cross-sectional view of a portion of the
orthopedic plate taken along line XXIII-XXIII in FIG. 20.
[0040] FIG. 24 shows a perspective view of a bone anchor assembly
according to another embodiment of the present invention.
[0041] FIG. 25 shows a perspective view of an embodiment of a hook
member of the assembly of FIG. 24.
[0042] FIG. 26 shows a front view of the hook member of FIG.
25.
[0043] FIG. 27 shows a perspective view of the bone anchor assembly
of FIG. 24 prior to assembly.
[0044] FIG. 28 shows a partial cross-sectional view of an offset
member according to another embodiment of the present
invention.
[0045] FIG. 28a shows a partial cross-sectional view of an offset
member according to a further embodiment of the present
invention.
[0046] FIG. 29 shows a side view of the offset member of FIG.
28.
[0047] FIG. 30 shows a top view of the offset member of FIG.
28.
[0048] FIG. 31 shows an end view of the offset member of FIG.
28.
[0049] FIG. 32 shows a cross-sectional view of the offset member of
FIG. 28.
[0050] FIG. 33 shows a side view of an offset member and a set
screw according to a further embodiment of the present
invention.
[0051] FIG. 34 shows a cross-sectional view of the offset member of
FIG. 33.
[0052] FIG. 35 shows a top view of the offset member of FIG.
33.
[0053] FIG. 36 shows an end view of the offset member of FIG.
33.
[0054] FIG. 37 shows an end view of the set screw of FIG. 33.
[0055] FIG. 38 shows a cross-sectional view of the set screw taken
along line XXXVIII-XXXVIII in FIG. 37.
[0056] FIG. 39 shows a cross-sectional view of the set screw of
FIG. 37.
[0057] FIG. 40 shows a side view of a cross-link connector
according to another embodiment of the present invention.
[0058] FIG. 41 shows a top view of the cross-link connector of FIG.
40.
[0059] FIG. 42 shows an enlarged view of a portion of the
cross-link connector of FIG. 40.
[0060] FIG. 43 shows a cross-link connector with an arched
cylindrical member.
[0061] FIG. 44 shows an end view of a set screw according to
another embodiment of the present invention.
[0062] FIG. 45 shows a cross-sectional view of the set screw taken
along line XLV-XLV in FIG. 44.
[0063] FIG. 46 shows a perspective view of a bone anchor assembly
according to a further embodiment of the present invention.
[0064] FIG. 47 shows an exploded view of the bone anchor assembly
of FIG. 46.
[0065] FIG. 48 shows a cross-sectional view of a hook member.
[0066] FIG. 49 shows a top view of an occipital-cervical rod.
[0067] FIG. 50 shows a side view of an occipital-cervical rod.
[0068] FIG. 51 shows a cross-sectional view of the
occipital-cervical rod taken along line LI-LI in FIG. 49.
[0069] FIG. 52 shows a cross-sectional view of the
occipital-cervical rod taken along line in FIG. 49.
[0070] FIG. 53 shows a partial cross-sectional view of a bone
anchor assembly according to another embodiment of the present
invention.
[0071] FIG. 54 shows a cross-sectional view of an embodiment of a
saddle member shown in FIG. 53.
[0072] FIG. 55 shows a top view of the saddle member of FIG.
54.
[0073] FIG. 56 shows a cross-sectional view of a washer shown in
FIG. 53.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0074] For the purpose of promoting an understanding of the
principles of the invention, reference will now be made to the
embodiments illustrated in the drawings and specific language will
be used to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended, such alterations and further modifications in the
illustrated device, and such further applications of the principles
of the invention as illustrated therein, being contemplated as
would normally occur to one skilled in the art to which the
invention relates.
[0075] In FIG. 1, there is shown an embodiment of a multi-axial
bone anchor assembly 20 according to the present invention. Bone
anchor assembly 20 includes a saddle member 22, a bone anchoring
member 24, and a washer (crown member) 26. In some embodiments,
assembly 20 will further include a C-shaped snap ring 28 and a set
screw 30, which are fitted with saddle member 22 as will be
described hereafter.
[0076] As shown in FIGS. 1-4, saddle member 22 generally has a
U-shape, with two upright portions 32 defining a channel 34
extending through saddle member 22. Channel 34 is then configured
to accommodate an elongated member 36, such as a spinal rod. For
posterior cervical fixation, rod 36 may have one of a number of
desired lengths. As seen in FIG. 1, the width of channel 34 is
slightly larger than the diameter of rod 36, which allows easier
insertion of rod 36 into channel 34, also allows for compensation
for contouring of the rod, and allows use of a range of rod sizes
with the same saddle member 22. Saddle member 22 further includes a
hole 38 therethrough, hole 38 being in one particular embodiment
substantially perpendicular to channel 34 and substantially
parallel to upright portions 32.
[0077] In a particular embodiment of saddle member 22, illustrated
in FIGS. 2-5, upright portions 32 each have an outer surface 40 and
an inner surface 42. Inner surfaces 42 are parallel to hole 38,
along a longitudinal axis of saddle member 22. Outer surfaces 40
are angled with respect to inner surfaces 42 and the longitudinal
axis of saddle member 22. In one specific embodiment, outer
surfaces 40 have an inward taper 43, which taper allows for easier
handling of the saddle member 22 and reduced bulk of saddle member
22. Near the bottom of saddle member 22, hole 38 is narrowed by a
wall portion 44. Below wall portion 44, hole 38 opens outward by
virtue of a conical wall portion 46. Conical wall portion 46 allows
bone anchor member 24 to be positioned in any of an infinite number
of angular positions relative to saddle member 22 by reducing
interference of the lower portion of saddle member 22 with a shank
portion of bone anchor member 24.
[0078] The illustrated embodiment of saddle member 22 further
includes an inner groove 48 that extends around hole 38. Groove 48
is configured to accommodate snap ring 28 in a compressed
condition, i.e., the outer diameter of groove 48 is at least
slightly smaller than the normal uncompressed outer diameter of
snap ring 28. The illustrated embodiment of saddle assembly 22
further includes a trough 50 extending longitudinally within each
of upright portions 32. Trough 50 accommodates placement of washer
26, as further described below, and may have a rounded (e.g.
cylindrical), squared, or other appropriate shape to accommodate
washer 26. Upright portions 32 further include an internally
threaded portion 52, as shown in FIGS. 1 and 3. Internally threaded
portions 52 are configured to be threadedly coupled with set screw
30, as described hereafter.
[0079] As shown in FIGS. 6-8, one embodiment of the bone anchor
member 24 of the present invention has a threaded portion 56 and a
head portion 58. In a specific embodiment, threaded portion 56
includes a thread 60 having a forward or leading flank 62 and a
rearward or load flank 64 and a root surface 66, in which load
flank 64 and root surface 66 form an acute angle. Such an acute
angle between load flank 64 and root surface 66 may be termed a
"reverse angle" thread.
[0080] Head portion 58 of bone anchor member 24 includes a lower
head portion 68 and an upper head portion 70. Lower head portion 68
is generally convex, and in one embodiment forms part of a sphere.
In the illustrated embodiment, the lower head portion 68 extends
from a shank portion 72 in a direction away from threaded portion
56, and stops at/or before a tangent to lower head portion 68 would
be parallel to a longitudinal axis L of bone anchor member 24.
Upper head portion 70 is also generally convex, and forms a part of
a sphere in the illustrated embodiment. Upper head portion 70 is
diametrally smaller than lower head portion 68 and head portions 68
and 70 are connected by a lip 74. A tool-engaging recess 76 is
formed in upper head portion 70, and may extend into lower head
portion 68. In another embodiment shown in FIG. 53, head portion
58a of bone anchor member 24a does not have a lip 74.
[0081] Referring now to FIGS. 9-11, there is shown an embodiment of
washer 26 of the present invention. Washer 26 includes an upper
portion 80, a lower portion 82, and a hole 84 therethrough. Upper
portion 80 and lower portion 82 may be constructed integrally or
may be separately constructed and attached together in any known
manner. An upper surface 86 of upper portion 80 includes recessed
portions 88 in the illustrated embodiment, which recessed portions
88 form a part of a cylinder sized and configured to accommodate
placement of an elongated member (such as rod 36 of FIG. 1)
therein. Lower portion 82 further includes an upper surface 83 that
faces snap ring 28.
[0082] Referring now to FIG. 11, washer 26 has a hole 84 provided
through both upper portion 80 and lower portion 82. Hole 84
includes a lower concave surface 96 and a cylindrical surface 98.
Concave surface 96 in one specific embodiment has a spherical shape
so as to substantially coincide with a portion of upper head
portion 70 of anchoring member 24. Lower portion 82 is generally in
the shape of a circular disc, and includes two projections 90
extending radially therefrom. Projections 20 in conjunction with
troughs 50 align recessed portions 88 of washer 26 with channel 34
and prevent rotation of washer 26 so as to minimize misalignment
between rod 36 and recessed portions 88.
[0083] In one embodiment, shown in FIGS. 9-10, projections 90 each
include two substantially planar side surfaces 92, and an end
surface 94 that is rounded and may form a portion of a cylinder.
Projections 90 are sized and shaped so as to fit and slide easily
within the troughs 50 upright portions 32 of saddle member 22. In
another embodiment illustrated in FIG. 12, projections 90a each
include a rounded end surface 100.
[0084] Multi-axial bone anchor assembly 20 can further include a
set screw 30. As illustrated in FIGS. 13-16, set screw 30 is
generally cylindrical and has external threads 102. External
threads 102, in one embodiment, are buttress threads. In another
embodiment, threads 102 could be reverse angle threads so as to
minimize splaying between the two upright members 32. An example of
such reverse angle threading is disclosed in U.S. patent
application Ser. No. 09/188,825, which is hereby incorporated by
reference.
[0085] Set screw 30, in the embodiment illustrated in FIGS. 13-14,
has at one end a tool-engaging portion 104. Tool-engaging portion
104 has a rounded end surface 106 and substantially planar
tool-engaging surfaces 108. Since end surface 106 is rounded,
internal trauma to a patient can be reduced. Tool-engaging surfaces
108, in one embodiment, are oriented in a hexagonal configuration.
Once set screw 30 is secured to saddle member 22, tool engaging
portion 104 can be sheared off or otherwise removed so as to
further reduce the profile of assembly 20. As illustrated in FIGS.
15-16, another embodiment of set screw 30a includes a substantially
flat end surface 110 in order to minimize the profile of assembly
20. Set screw 30a further includes a tool-engaging bore 112.
Tool-engaging bore 112 is used in conjunction with a tool for
introducing set screw 30a into saddle member 22.
[0086] In certain embodiments, multi-axial bone anchor assembly 20
includes snap ring 28 in order to secure washer 20 against
anchoring member 24. One embodiment of such a snap ring 28 is shown
in FIGS. 17-18. Snap ring 28 has a central opening 114 and a
compression slot 116 defined therein. Snap ring 28 further has a
first surface 118, an opposite second surface 120, an inner lateral
surface 122 defining opening 114, and an outer lateral surface 124.
Compression slot 116 allows snap ring 28 to compress and fit into
inner groove 48 of saddle member 22. The diameter of the entrance
of groove 48 is at least slightly smaller than the outer diameter
126 of an uncompressed snap ring 28. Opening 114 of snap ring 28
has an inner diameter, which allows snap ring 28 to fit around
upper portion 80 of washer 26. One of the surfaces 118 and 120
engage the upper surface 83 of lower portion 82 in order to secure
washer 26. Snap ring 28 can have a square cross-section, as shown
in FIG. 1, or a circular or other appropriate shape cross-section,
and in one particular embodiment is made of a shape memory alloy
such as nitinol.
[0087] Another embodiment of snap ring 28' is illustrated in FIG.
17a. Snap ring 28' is non-planar, and in one embodiment has a
series of undulations forming relative crests 129a and relative
troughs 129b therein. Alternatively, non-planar snap ring 28' could
have other curved configurations, or could have extending
finger-spring elements along it. When assembly 20 (or assembly 262
described below) is assembled, non-planar snap ring 28' allows less
play between saddle member 22, anchoring member 24 and washer 26
(or similar parts of assembly 262, described below) because
non-planar snap-ring 28' fills a greater portion of groove 48 of
saddle member 22.
[0088] An embodiment of an orthopedic fixation plate 130 according
to the present invention is illustrated in FIGS. 19-23. In one
form, orthopedic plate 130 is secured to the occipital bone of a
skull. However, it should be appreciated that plate 130 can be
secured to other bones. Orthopedic plate 130 includes a
cross-shaped member 132 having a first longitudinal arm (end) 134
to a second longitudinal arm (end) 136 along a longitudinal axis.
Cross-shaped member 132 further has a first transverse arm (end)
138 and a second transverse arm (end) 140 connected together along
an axis transverse with respect to the longitudinal axis.
Orthopedic plate 130 further includes a pair of saddle members 22a
integrally formed on or joined to longitudinal arms 134 and 136. It
should be appreciated that saddle members 22 can also be pivotally
coupled to cross-shaped member 132 so as to provide greater
positioning freedom. As illustrated in FIG. 22, saddle members 22a
each include a pair of upright members 32a and a channel 34a
defined between upright members 32a. Upright members 32a include
threaded portions 52a configured to be threadedly coupled to a set
screw 30 in a manner as described above.
[0089] Orthopedic plate 130, in one embodiment, includes a set of
apertures 142. Bone anchors 24b (FIG. 6a) are secured in apertures
142 in order to secure plate 130 to the occipital bone of the
skull. As shown in FIG. 6a, anchor 24b includes a head portion 58b
having a convex underside 59a, which may be spherical, and a
beveled top 59b around a tool-engaging recess 59c. Apertures 142
shown in FIGS. 19-23 for the particular embodiment are provided on
both the longitudinal arms 134, 136 and the transverse arms 138,
140 in a cross configuration in order to provide greater stability.
As shown in FIG. 23, aperture 142 includes a lower conical portion
144 and an upper conical portion 146. Lower conical portion 144
widens towards a lower surface 148 of orthopedic plate 130, and
upper conical portion 146 widens towards an upper surface 150 of
orthopedic plate 130. Upper and lower conical portions 144,146
allow a bone screw to be easily positioned at varying angular
positions relative to orthopedic plate 130. In one embodiment,
opposing walls of lower conical portion 146 are oriented at about
sixty degrees (60.degree.) with respect to one another, and
opposing walls of upper conical portion 146 are oriented at about
forty-five degrees (45.degree.) with respect to one another. Cross
member 130 further includes a beveled outer peripheral surface 152
between lower surface 148 and upper surface 150.
[0090] In one particular embodiment, cross member 132 is curved
along the longitudinal axis between longitudinal arms 134 and 136,
and is also slightly curved along the transverse axis. This
curvature of cross member 132 allows orthopedic plate 130 to better
match the contour of the occipital bone of the skull. It should be
understood that cross member 132 can also be curved along only one
of the axes or substantially flat along both axes or can be
otherwise contoured prior to or during surgery in order to match
specific patient anatomy.
[0091] In FIG. 24, there is shown another embodiment of a
multi-axial bone anchor assembly 160 according to the present
invention. Anchor assembly includes a saddle member 162 and an
offset connector 164 coupled to saddle member 162. As shown in
FIGS. 25-26, saddle member 162 essentially includes the same
features as described above in reference to saddle member 22.
Saddle member 162 includes two upright portions 32b defining
channel 34b. Channel 34b is configured to accommodate an elongated
member 36b. Upright portions 32b each has outer surface 40b that is
angled with respect to inner surface 42b. Upright portions 32b
further include an internally threaded portion 52b. Internally
threaded portions 52b are configured to be threadedly coupled with
set screw 30.
[0092] Additionally, saddle member 162 includes a transverse hole
166 defined in both upright portions 32b. Transverse hole 166 is
oriented transverse with respect to channel 34b, and transverse
hole 166 is adapted to receive a rod (such as rod 36 in FIG. 1) or
offset connector 164. This configuration between channel 34b and
transverse hole 166 provides a physician with greater flexibility
during surgery, since offset connector 164 can be oriented at
different angles with respect to saddle member 162. Offset
connector 164 further can be laterally positioned at any of an
infinite number of distances from saddle member 162, because
transverse hole 166 passes through both upright portions 32.
Further, saddle member 162 is dually useful, because a rod (such as
rod 36 in FIG. 1) or offset connector 164 can be coupled to either
channel 34b or transverse hole 166.
[0093] Saddle member 162, in one embodiment, further includes a
hook member 168 for engaging bones in a generally known manner.
Hook member 168 has a curved portion 170 extending from upright
portions 32 and a substantially straight portion 172 extending from
curved portion 170. Straight portion 174 has a beveled bottom
surface 174, which reduces trauma when hook member 168 is attached.
It should be appreciated that hook member 168 could be replaced
with another anchoring member, such as anchoring members 24 or 24a
(FIGS. 6, 53) in order to attach saddle member 162 to a bone.
[0094] Referring now generally to FIGS. 27-32, offset connector 164
includes a coupling member 176 integrally formed or otherwise
joined to a body 178. In one form, coupling member 176 is a
cylindrical rod. Body 178 has a rod receiving bore 180 that is
adapted to receive rod 36 and a threaded bore 182 that intersects
rod receiving bore 180. A set screw 30 is screwed into threaded
bore 182 in order to secure rod 36 to offset connector 164. Body
178 further can include a beveled outer edge 184 (FIG. 27) in order
to minimize trauma to a patient. In another embodiment shown in
FIGS. 28-32, rod receiving bore 180 has a slot 186 defined therein.
Edges 187 are formed between slot 186 and rod receiving bore 180.
Edges 187 along with set screw 30 provide three lines of contact
with a rod 36 coupled to offset connector 164 so as to strengthen
the connection. In still yet another embodiment shown in FIG. 28a,
offset connector 164a has a pair of upright portions 32c defining a
channel 34c adapted to receive a rod. Upright portions 32c have
internally threaded portions 52c for engaging a set screw 30.
[0095] Referring now to FIG. 27, offset connector 164 is coupled to
saddle member 162 by inserting coupling member 176 in direction A
into transverse hole 166. Set screw 30 is used to secure coupling
member 176 to saddle 160. Offset connector 164 can be laterally
positioned with respect to saddle member 162 by moving coupling
member 176 within transverse hole 166.
[0096] An offset connector 188 along with a set screw 189 according
to still yet another embodiment of the present invention are shown
in FIGS. 33-39. As shown in FIGS. 33-36, offset connector 188
includes a coupling member 176, and a pair of laterally oriented
body members 190 and 192. A channel 194 is defined between body
members 190 and 192, and channel 194 is adapted to receive rod 36.
One of the body members 192 is slightly longer than the other and
has a threaded bore 196 defined therein. Set screw 189 is threaded
into bore 196 so as to secure rod R to offset connector 188. As
illustrated in FIGS. 37-39, set screw 189 is generally cylindrical
and has threads 198. Set screw 189 further has a tool engaging bore
defined in one end and a pointed tip 202 at the other end. Pointed
tip 202 engages rod 36 when rod 36 is coupled to offset connector
188.
[0097] A cross-link connector 204 according to one embodiment,
which is illustrated in FIGS. 40-42, is adapted to be bent about
multiple axes. Cross-link connector 204 has a pair of coupling ends
206 integrally connected together with a cylindrical member 208.
The cylindrical shape of cylindrical member 208 allows cross-link
connector 204 to be bent in any of an infinite number of
directions. In one particular embodiment shown in FIG. 43,
cylindrical member 208a is pre-formed with an arch so as to avoid
any obstructions between the two ends 206. Each coupling end 206
includes a threaded bore 210 with an opening 211 in which a set
screw 30 is threaded and a curved member 212 that defines a cavity
214 adapted to receive rod R. Opening 215 of cavity 214 is defined
in a side of cross-link connector 204 opposite opening 211 of
threaded bore 210. This configuration allows cross-link connector
204 to be secured to adjacent rods after the adjacent rods are
situated within the patient. In one embodiment, threaded bore 210
is positioned at about fifty-five degrees (55.degree.) relative to
a longitudinal axis that extends between the ends 206. Cross-link
connectors are used to link adjacent rods within a patient. An
obstruction (such as another rod or bone) may prevent a typical
cross-link connector from linking adjacent rods together. The
cross-link connector 204 of the present invention solves this
problem by being adapted to bend along multiple axes.
[0098] One embodiment of a set screw 216 that is adapted to be
threaded into threaded bore 210 is illustrated in FIGS. 44-45. Set
screw 216 has one end with a tool engaging bore 218, a rod engaging
end 222 and a threaded portion 220 provided between both ends. Rod
engaging end 222 has a frusto-conical portion 224 adjacent threaded
portion 220 and a flat portion 226, which frusto-conical portion
224 contacts rod 36. In one form, frusto-conical portion 224 has an
angle 228 of about forty degrees) (40.degree..
[0099] In FIG. 46, there is shown a multi-axial bone anchor
assembly 230 according to another embodiment of the present
invention. Assembly 230 has a generally U-shaped saddle member 22,
which was described above with reference to FIGS. 2-5, coupled to a
hook anchor member 168a. In this embodiment, saddle member 22 may
be formed without groove 48. As previously discussed, saddle member
22 has a pair of upright portions 32 that define channel 34. Set
screw 30 is threadedly secured to threaded portion 52 of saddle
member 22 in order to secure rod 36 to saddle member 22. As shown
in FIGS. 47-48, hook member 168a has a curved portion 170a and a
substantially straight portion 172a. In this embodiment, hook
member 168a further includes a coupling (head) portion 232 that is
coupled to saddle member 22. Coupling portion 232 includes coupling
members 234 and a threaded hole 236 adapted to receive expansion
member 238. In one form, coupling portion 232 includes four members
234 having a part-spherical outer surface and expansion member 238
is a set screw. In one form, expansion member 238 at one end has a
tool engaging portion 240 and a threaded portion 242 at the other
end for securing expansion member 238 into hole 236. Expansion
member 238 further includes an expansion portion 244 located
between tool engaging portion 240 and threaded portion 242.
Expansion portion 244 contacts and expands semispherical members
234 to anchor saddle member 22 to hook member 168 and prevents
further rotation. In one form, expansion portion 244 has a conical
shape.
[0100] In use, coupling portion 232 is inserted into hole 38
through the bottom of saddle member 22. When saddle member 22 is
coupled to hook member 168a, the spherical shape formed between
semispherical members 234 allows saddle member 22 to rotate about
multiple axes. Expansion member 238, once secured in hole 236
causes coupling members 234 to splay into contact with saddle
member 22, thereby fixing the relative position between saddle
member 22 and hook member 168.
[0101] An embodiment of an occipital-cervical rod 246, which can be
attached to the above-described assemblies, is illustrated in FIGS.
49-52. Occipital-cervical rod 246 includes a plate portion 246a,
through which a plurality of apertures 248 are formed, and a rod
portion 246b. Apertures 248 may be oblong in shape. Defined along
plate portion 246a are an upper surface 250, a curved lower surface
252, and a pair of beveled side surfaces 254 between upper surface
250 and lower surface 252. Each aperture 248 includes an upper
portion 256 that widens towards upper surface 250 and a lower
portion 258 that widens towards lower surface 252. Grooves 260 are
defined around plate portion 246a of occipital-cervical rod 246 and
between adjacent apertures 248. Bone screws 24b (FIG. 6a) are
inserted into apertures 248 in order to secure plate portion 246a
to the occipital bone of a patient. Rod portion 246b extends along
the spinal column and can be attached to the spinal column using
the above-described or other connectors. Alternatively, plate
portion 246a can be attached to one or more vertebrae using bone
screws 24b (FIG. 6a), and rod portion 246b can extend upward and be
attached to the occipital bone using screws, hooks, cable, or other
attachment members.
[0102] In FIG. 53, there is shown another embodiment of a
multi-axial bone anchor assembly 262 according to the present
invention. Bone anchor assembly 262 includes a saddle member 22d, a
bone anchoring member 24a, and a washer 26d. Bone anchoring member
24a does not have a lip 74. In some embodiments, assembly 262 will
further include a C-shaped snap ring 28 and a set screw 30, which
are fitted with saddle member 22d in a manner described below.
[0103] As shown in FIGS. 54-55, saddle member 22d generally has a
U-shape, with two upright portions 32d defining a channel 34d
extending through saddle member 22d. Channel 34d is then configured
to accommodate an elongated member 36 (as described above). Saddle
member 22d further includes a hole 38d therethrough, hole 38d being
in one particular embodiment substantially perpendicular to channel
34d and substantially parallel to upright portions 32d. Upright
portions 32d are angled in a manner similar to the one as described
above with reference to FIGS. 2-3. Near the bottom of saddle member
22d, hole 38d is narrowed by a wall portion 44d. Below wall portion
44d, hole 38d opens outward by virtue of a wall portion 46d. Wall
portion 46d allows bone anchor member 24a to be positioned in any
of an infinite number of angular positions relative to saddle
member 22d by reducing interference of the lower portion of saddle
member 22d with a shank portion of bone anchor member 24a.
[0104] The particular illustrated embodiment of saddle member 22d
further includes an inner groove 48d. As illustrated, groove 48d
extends around hole 38d, and in this particular embodiment, groove
48d is uniform between a top portion of groove 48d and the bottom
portion thereof. Groove 48d is configured to accommodate snap ring
28 in a compressed condition. Groove 48d has a thickness 264 that
is, in one form, thicker than snap ring 28. Further, the
illustrated embodiment of saddle assembly 22d in FIGS. 54-55 does
not include a trough 50 that extends longitudinally within each of
upright portions 32d. Upright portions 32d further include
internally threaded portions 52d, which are configured to be
threadedly coupled with set screw 30.
[0105] Referring now to FIG. 56, there is shown another embodiment
of washer 26d according to the present invention. Washer 26d
includes an upper portion 80d, a lower portion 82d, a snap ring
recess 266, and a hole 84d therethrough. Upper portion 80d, lower
portion 82d, and snap ring recess 266 may be constructed integrally
or may be separately constructed and attached together in any known
manner. Snap ring 28 fits within recess 266 in order to secure
washer 26d within saddle member 22d. In one embodiment, assembly
262 is assembled by inserting anchoring member 24a through hole 38d
in saddle member 22d. Washer 26d, with snap ring 28 in at least a
portion of recess 266, is then inserted into hole 38d. Snap ring 28
contracts into recess 266 as washer 26d goes through saddle member
22d, and expands into groove 48d to hold washer 26d within saddle
member 22d. An elongated member is then inserted in channel 34d,
and a set screw (such as those described above) is threaded into
internally threaded portions 52d, saddle member 22d to lock the
elongated member, washer 26d and anchoring member 24a together.
[0106] Washer 26d has a hole 84d provided through both upper
portion 80d and lower portion 82d. Hole 84d includes a lower
concave surface 96d and a cylindrical surface 98d. Lower concave
surface 96d is adapted to accommodate head portion 58a of anchor
member 24a. In the particular embodiment illustrated in FIG. 56,
lower portion 82d is generally in the shape of a circular disc. In
this particular embodiment, lower portion 82d does not have
projections 90.
[0107] While the invention has been illustrated and described in
detail in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character. It
should be understood that only the preferred embodiments have been
shown and described and that all changes and modifications that
come within the spirit of the invention are desired to be
protected.
* * * * *