U.S. patent application number 14/026402 was filed with the patent office on 2014-08-14 for bone plate system and methods of using the same.
This patent application is currently assigned to Spinal USA, Inc.. The applicant listed for this patent is Spinal USA, Inc.. Invention is credited to John Franklin Cummins.
Application Number | 20140228892 14/026402 |
Document ID | / |
Family ID | 43497966 |
Filed Date | 2014-08-14 |
United States Patent
Application |
20140228892 |
Kind Code |
A1 |
Cummins; John Franklin |
August 14, 2014 |
BONE PLATE SYSTEM AND METHODS OF USING THE SAME
Abstract
A bone plate locking system including a threaded screw body
having a proximal end and a distal end and a plate with a
through-hole. The proximal end includes a head. The head includes
an upper portion, a groove adjacent the upper portion and a lower
portion adjacent the groove, wherein a center-axis of the groove is
off-axis to a center-axis of the threaded screw body. A locking
ring configured to reside within the groove of the head. The
through-hole includes an upper portion, a groove adjacent the upper
portion and a lower portion adjacent the groove. The head is
receivable in the through-hole. The locking ring is rotatably
positioned around the groove of the head such that in an unlocked
position the locking ring is outside the groove of the through-hole
and in a locked position the locking ring is at least partially
within the groove of the through-hole.
Inventors: |
Cummins; John Franklin;
(Kosciusko, MS) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Spinal USA, Inc. |
Parsippany |
NJ |
US |
|
|
Assignee: |
Spinal USA, Inc.
Parsippany
NJ
|
Family ID: |
43497966 |
Appl. No.: |
14/026402 |
Filed: |
September 13, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12842517 |
Jul 23, 2010 |
8535354 |
|
|
14026402 |
|
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|
61228521 |
Jul 24, 2009 |
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Current U.S.
Class: |
606/279 ;
606/246 |
Current CPC
Class: |
A61B 17/7059 20130101;
A61B 17/8047 20130101 |
Class at
Publication: |
606/279 ;
606/246 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Claims
1.-20. (canceled)
21. A spinal fixation system comprising: a fixation member having a
proximal end and a distal end, the proximal end comprising a head;
a locking ring configured to at least partially reside on the head,
wherein the locking ring is a non-continuous ring; and a spinal
implant comprising a through-hole, the through-hole comprising an
upper portion, a groove adjacent the upper portion and a lower
portion adjacent the groove, the head is receivable in the
through-hole; wherein the locking ring is adapted to be rotatably
positioned on the head such that in an unlocked position the
locking ring is outside the groove of the through-hole and in a
locked position the locking ring is at least partially within the
groove of the through-hole.
22. The spinal fixation system of claim 21, wherein the head
comprises an upper portion, a lower portion, and a groove adjacent
the upper portion and lower portion.
23. The spinal fixation system of claim 22, wherein the locking
ring is adapted to be rotatably positioned around the groove of the
head.
24. The spinal fixation system of claim 22, wherein the head of the
fixation member further comprises a first notch in at least a
portion of the upper portion of the head, the locking ring further
comprises a posterior surface and a first protrusion on at least a
portion of the posterior surface that is configured to reside
within the first notch in the upper portion of the head, and the
first protrusion is at one end of the first notch in the upper
portion of the head in the unlocked position and the first
protrusion is at another end of the first notch in the upper
portion of the head in the locked position.
25. The spinal fixation system of claim 24, wherein the head of the
fixation member further comprises a second notch in at least a
portion of the upper portion, the locking ring further comprises an
inner surface and a second protrusion on at least a portion of the
inner surface, and the second protrusion of the locking ring is
within the second notch in the groove of the head in the unlocked
position and the second protrusion is outside the second notch in
the groove of the head in the locked position.
26. The spinal fixation system of claim 22, wherein the head of the
fixation member further comprises a notch in at least a portion of
the upper portion, the locking ring further comprises an inner
surface and a protrusion on at least a portion of the inner
surface, and the protrusion of the locking ring is within the notch
in the groove of the head in the unlocked position and the
protrusion is outside the notch in the groove of the head in the
locked position.
27. The spinal fixation system of claim 21, wherein the locking
ring has a c-shape.
28. The spinal fixation system of claim 21, wherein the locking
ring comprises an outer curved surface and an inner curved surface,
at least a portion of the locking ring has a distance between the
outer curved surface and the inner curved surface that is greater
than at least another portion of the locking ring.
29. The spinal fixation system of claim 21, further comprising more
than one fixation member and more than one locking ring, wherein
the spinal implant comprises more than one through-hole.
30. The spinal fixation system of claim 21, wherein in the locked
position, the locking ring substantially limits the fixation member
from backing out of the spinal implant.
31. The spinal fixation system of claim 21, wherein the locking
ring is able to be in a locked position when the fixation member is
non-perpendicular to the spinal implant.
32. The spinal fixation system of claim 21, wherein the locking
ring is non-symmetrical.
33. The spinal fixation system of claim 21, wherein the locking
ring comprises a hole to rotate the locking ring.
34. The spinal fixation system of claim 21, wherein the fixation
member is a screw.
35. The spinal fixation system of claim 21, wherein the fixation
member has a linear center-axis.
36. A spinal fixation system comprising: a threaded screw body
having a center-axis, a proximal end, and a distal end, the
proximal end comprising a head; and a locking ring configured to be
rotatably positioned on the head, wherein the locking ring at least
partially resides on the head and is configured to rotate about an
axis that is off-axis to the center-axis of the screw body.
37. The spinal fixation system of claim 36, wherein the head
comprises an upper portion, a lower portion, and a groove adjacent
the upper portion and lower portion.
38. The spinal fixation system of claim 37, wherein the locking
ring is adapted to be rotatably positioned around the groove of the
head.
39. The spinal fixation system of claim 36, further comprising a
spinal implant configured to receive the threaded screw body.
40. The spinal fixation system of claim 39, wherein the spinal
implant is a plate.
41. The spinal fixation system of claim 39, wherein the spinal
implant comprises a through-hole having an upper portion, a lower
portion, and a groove adjacent the upper portion and the lower
portion, wherein the head of the threaded screw body is receivable
in the through-hole.
42. The spinal fixation system of claim 41, wherein the locking
ring is adapted to rotate from an unlocked position in which the
locking ring is outside the groove of the through-hole to a locked
position in which the locking ring is at least partially within the
groove of the through-hole.
43. The spinal fixation system of claim 36, wherein the axis about
which the locking ring rotates is substantially parallel to the
center-axis of the screw.
44. A method of securing a spinal implant, the method comprising:
positioning a spinal implant within a patient, the spinal implant
comprising a through-hole with a groove; inserting a threaded screw
body through the through-hole and into a vertebral body, the
threaded screw body having a center-axis, a proximal end, and a
distal end with a head positioned within the through-hole; and
rotating a locking ring positioned on the head of the threaded
screw body from an unlocked position to a locked position in which
the locking ring is positioned at least partially within the
groove.
45. The method of claim 44, wherein the locking ring rotates about
an axis that is off-axis to the center-axis of the screw.
46. The method of claim 44, wherein the locking ring is a
non-continuous ring.
47. The method of claim 46, wherein the locking ring has a c-shape.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Any and all applications for which a foreign or domestic
priority claim is identified in the Application Data Sheet as filed
with the present application, are hereby incorporated by reference
under 37 CFR 1.57. The present application is a continuation of
U.S. patent application Ser. No. 12/842,517, filed Jul. 23, 2010,
and issued as U.S. Pat. No. 8,535,354, which claims the priority
benefit of U.S. Provisional Application Ser. No. 61/228,521, filed
on Jul. 24, 2009, the entirety of each of which is hereby
incorporated by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] Disclosed herein are bone plate systems related to the field
of orthopedic surgery. More particularly, certain embodiments
disclosed herein relate to bone plate systems with a locking screw
and an anterior cervical spinal plate and methods of use.
[0004] 2. Description of the Related Art
[0005] Spinal fusion encompasses a surgical technique in which two
or more vertebrae are connected together. This technique may be
used for multiple indications, including abnormal spinal curvature
(e.g., scoliosis) and weakening or injuring of the vertebrae or
spinal disc.
[0006] In some instances, this process is accomplished and/or
supplemented using a plate to join together adjacent vertebrae. The
plate is affixed by implanting a plurality of screws through the
plate and into the vertebrae bodies of adjacent vertebrae. A screw
may have an enlarged head that interfaces with the plate having a
corresponding cavity, thus allowing for a range of polyaxial
articulation between the screw and the plate. A common risk with
prior bone plate system designs include backing out and loosening
of the screw after being implanted.
SUMMARY
[0007] Described herein are bone plate locking systems that can
include a screw, a locking ring and a plate. Methods of assembling
and implanting the bone plate locking systems described herein are
also included. These bone plate locking systems and related methods
are described in greater detail below.
[0008] In certain embodiments, the bone plate locking system
includes a threaded screw body having a proximal end and a distal
end. The proximal end includes a head. The head includes an upper
portion, a groove adjacent the upper portion and a lower portion
adjacent the groove. In addition, a center-axis of the groove is
off-axis to a center-axis of the threaded screw body. The bone
plate system further includes a locking ring that is configured to
reside within the groove of the head, and a plate that includes an
anterior surface, a posterior surface and a through-hole through
the anterior surface and the posterior surface. The through-hole
includes an upper portion, a groove adjacent the upper portion and
a lower portion adjacent the groove. The head is receivable in the
through-hole. The locking ring is rotatably positioned around the
groove of the head such that in an unlocked position the locking
ring is outside the groove of the through-hole and in a locked
position the locking ring is at least partially within the groove
of the through-hole.
[0009] In some embodiments, the groove of the head defines an at
least partially circular surface. The locking ring further includes
an outer curved surface, an inner curved surface, an anterior
surface and a posterior surface. In certain embodiments, the bone
plate locking system includes a notch in at least a portion of the
upper portion of the head. The locking ring further includes a
first protrusion on at least a portion of the posterior surface of
the locking ring that is configured to reside within the notch in
the upper portion of the head. The locking ring is rotatably
positioned around the groove of the head such that in an unlocked
position the first protrusion is at one end of the notch in the
upper portion of the head, and in a locked position the first
protrusion is at another end of the notch in the upper portion of
the head.
[0010] In certain embodiments, the bone plate locking system
includes a notch in at least a portion of the groove of the head,
and the locking ring further includes a second protrusion on at
least a portion of the inner surface. The locking ring being
rotatably positioned around the groove of the head such that in an
unlocked position the second protrusion of the locking ring is
within the notch in the groove of the head, and in a locked
position the second protrusion of the locking ring is outside the
notch in the groove of the head.
[0011] In certain embodiments, a method of fixing adjacent
vertebrae includes providing a plate that includes an anterior
surface, a posterior surface and a plurality of through-holes
through the anterior surface and the posterior surface, and
positioning the plate on the anterior surface of at least two
adjacent vertebral bodies. At least one through-hole is positioned
over a first vertebral body and a second through-hole is positioned
over a second vertebral body. The method further includes inserting
a first screw through a first through-hole into the first vertebral
body and a second screw through a second through-hole into the
second vertebral body. The first and second screws include heads
positioned within first and second through-holes and threaded
bodies engaging the vertebral bodies. The method includes rotating
a locking ring positioned within a groove of the head of one of
said screws to a position where the locking ring is positioned at
least partially within a groove of one of the through-holes to
limit the screw backing out of the through-hole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is an exploded view of an embodiment of a bone plate
system.
[0013] FIG. 2 is a side view of an embodiment of a screw.
[0014] FIG. 3 is a top view of the screw illustrated in FIG. 2.
[0015] FIG. 4 is a top view of the screw illustrated in FIG. 3 and
an embodiment of a locking ring in an unlocked position.
[0016] FIG. 5 is a top view of the screw illustrated in FIG. 3 and
an embodiment of a locking ring in a locked position.
[0017] FIG. 6 is a bottom view of the screw and the locking ring in
the configuration illustrated in FIG. 5.
[0018] FIG. 7 is a cross-sectional view of an embodiment of a
plate.
[0019] FIG. 8 is a cross-sectional view of an embodiment of a bone
plate system wherein the locking ring on the left is in an unlocked
position and the locking ring on the right is in a locked
position.
[0020] FIG. 9 is a top view of the bone plate system illustrated in
FIG. 8 wherein the locking ring on the left is in an unlocked
position and the locking ring on the right is in a locked
position.
[0021] FIG. 10 is a perspective view of an embodiment of a locking
ring.
[0022] FIG. 11 is a perspective view of an embodiment of a
screw.
[0023] FIG. 12A is a top view of the screw illustrated in FIG. 11
and the locking ring illustrated in FIG. 10 in an unlocked
position.
[0024] FIG. 12B is a top view of the screw illustrated in FIG. 11
and the locking ring illustrated in FIG. 10 in a locked
position.
[0025] FIG. 12C is a perspective view of the screw and the locking
ring illustrated in FIG. 12A in an unlocked position.
[0026] FIG. 12D is a perspective view of the screw and the locking
ring illustrated in FIG. 12B in a locked position.
[0027] FIG. 13 is a cross-sectional view of an embodiment of a bone
plate system illustrating that certain embodiments of bone plate
systems are able to have the screw positioned at different angles
relative to the plate.
[0028] FIG. 14 is a perspective view of an embodiment of a bone
plate system implanted in vertebrae of a patient.
DETAILED DESCRIPTION
[0029] FIG. 1 shows an embodiment directed to a bone plate locking
system which can include one or more screws 10, a locking ring 12
and a plate 14. In certain embodiments, the screw 10 is inserted
into the plate 14 and the screw 10 is screwed into a vertebra. The
locking ring 12 can be rotated between an unlocked position and a
locked position so that in a locked position the screw 10 will
resist backing out of the plate 14.
[0030] FIG. 2 illustrates a side view of one embodiment of a screw
10. The screw 10 may be a threaded screw body. The screw 10 may
have a proximal end 22 and a distal end 20. The distal end 20 may
be at least partially threaded. In some embodiments, the distal end
20 of the screw body 10 may be adapted for implantation into the
spine of a patient. For example, the distal end 20 of the screw 10
can be adapted for implantation into a vertebral body of a
patient's lumber, cervical or thoracic spine. The proximal end 22
may include an enlarged head 24. The head 24 may have an upper
portion 26, a groove 28 adjacent the upper portion 26, and a lower
portion 30 adjacent the groove 28.
[0031] The groove 28 can define a curved surface, and preferably an
at least partially circular surface. FIG. 3 illustrates a top view
of the screw 10. The screw 10 can have a center of axis 34, and the
groove 28 can also have a center of axis 32. The center of axis 34
of the screw 10 can be substantially parallel to the length of the
screw 10 and preferably passes through the distal tip of the distal
end 20 of the screw 10. The center of axis 32 of the groove 28 can
be off-axis to the center of axis 34 of the screw 10. For example,
the center of axis 32 of the groove 28 can be different from the
center of axis 34 of the screw 10. In certain embodiments, the
center of axis 32 of the groove 28 and the center of axis 34 of the
screw 10 are substantially parallel. In other embodiments, the
center of axis 32 of the groove 28 and the center of axis 34 of the
screw 10 are non-parallel. In certain embodiments, at least a
portion of the upper portion 26 and/or the lower portion 30 of the
head 24 extend beyond an outer periphery of the groove 28. In
further embodiments, substantially all of the upper portion 26
and/or the lower portion 30 of the head 24 extend beyond an outer
periphery of the groove 28. As shown in FIG. 2, at least a portion
of the lower portion 30 extends beyond an outer periphery of the
upper portion 26 of the head 24. The lower portion 30 of the head
24 preferably has a planar surface on the proximal end of the lower
portion 30 and is oriented substantially perpendicular to the
center of axis 34 of the screw 10. The upper portion 26 of the head
can also have a planar surface on the distal end of the upper
portion 26 and is oriented substantially perpendicular to the
center of axis 34 of the screw 10. The planar surfaces can be
substantially flat. In other embodiments, other suitable screw head
features can be employed to facilitate coupling the screw head with
the locking ring. For example, the screw head may include one or
more grooves, slots, tracks, holes, ridges, indentations,
protrusions, pins, followers or other features to facilitate
holding a locking ring in a preferred configuration, or facilitate
moving the locking ring from a first position to a second position
relative to the screw head. Various shapes and geometries of the
screw head may facilitate holding or moving the locking ring in a
preferred manner.
[0032] FIGS. 4 and 5 illustrate top views of a head 24 of a screw
10 and a locking ring 12. The locking ring 12 preferably resides at
least partially within the groove 28 of the head 24. In certain
embodiments, the locking ring 12 is removable from the groove 28.
The locking ring 12 can be at least partially rotatable within the
groove 28 of the head 24. The locking ring 12 may include a means
to rotate the locking ring 12. For example, the locking ring 12 may
include a hole 40 so that a tool can be inserted into the hole 40
to rotate the locking ring 12. The position of the locking ring 12
in FIG. 4 illustrates an unlocked position. FIG. 5 illustrates the
locking ring 12 in a locked position. The locking ring 12 rotates
around the center of axis 32 of the groove 28. The locking ring 12
may be a continuous ring or may not be a continuous ring. For
example, the locking ring 12 can have a c-shape, as shown in FIGS.
1, 4 and 5. The locking ring 12 may have an outer curved surface 42
and an inner curved surface 44. In certain embodiments, at least a
portion of the locking ring 12 has a distance between the outer
curved surface 42 and the inner curved surface 44 that is greater
than at least another portion of the locking ring 12. For example,
the locking ring 12 can have a partial moon shape or crescent
shape. In the locked position, the locking ring 12 may at least
partially extend outwardly beyond the lower portion 30 of the head
24, as illustrated in FIG. 5. FIG. 6 illustrates a bottom view of
the locking ring 12 in a locked position. In certain embodiments,
the locking ring 12 does not extend beyond the lower portion 30 of
the head 24 in an unlocked position. In some embodiments, the
locking ring 12 is able to rotate completely around the center of
axis 32 of the groove 28. In other embodiments, the locking ring 12
is only able to partially rotate around the center of axis 32 of
the groove 28. In other embodiments, other suitable locking ring
features can be employed to facilitate coupling the screw head with
the locking ring. For example, the locking may include one or more
grooves, slots, tracks, holes, ridges, indentations, protrusions,
pins, followers or other features to facilitate holding a locking
ring in a preferred configuration, or facilitate moving the locking
ring from a first position to a second position relative to the
screw head. Various shapes and geometries of the locking ring may
facilitate holding or moving the locking ring in a preferred
manner. Additionally, locking rings can include any suitable shape
adapted for coupling the locking ring to the screw head and/or
adapted for movement relative to the screw head between an unlocked
configuration and a locked configuration. For example, movement of
locking ring relative to the screw head may include rotational
movement, translational movement, pivotal movement, and/or other
suitable movement. Additionally, locking rings can include any
suitable shape for facilitating screw insertion in a first position
and providing a blocking feature to limit screw backout in a second
position. For example, the shape of the locking rings can include
one or more of the following shapes: ring shaped, crescent shaped,
u-shaped, v-shaped, c-shaped, j-shaped, symmetrical,
non-symmetrical, elongated, oblong, curved, angled and/or any other
shape suitable for not interfering with screw insertion in a first
position and suitable for blocking the screw to limit back out in a
second position. In some embodiments the locking rings can be
movably fixed or attached to the screw head prior to insertion of
the screw in a patient. In other embodiments the locking rings can
be coupled to the screw head after insertion.
[0033] FIG. 7 illustrates a cross-sectional view through a plate
14. The plate includes a posterior surface 74, an anterior surface
72 and at least one through-hole 70 through the posterior surface
74 and the anterior surface 72. In certain embodiments, the plate
14 includes more than one through-hole 70. The through-hole 70 can
include an upper portion 76, a groove 78 adjacent the upper portion
76, and a lower portion 80 adjacent the groove 78. The embodiment
of FIG. 1 illustrates three pairs of openings or through-holes 70
that are configured to be aligned over adjacent vertebral bodies.
The plate 14 may be placed over a desired spinal location, such as
on in the lumbar, thoracic or cervical spine. For example, the
plate 14 may be configured to be placed over an anterior surface of
the spine, and in an embodiment, the posterior surface may be
concave along a longitudinal axis 82 of the plate 14.
[0034] FIG. 8 illustrates a cross-sectional view of screws 10
inserted in the through-holes 70 of a plate 14. The locking ring 12
within the screw 10 on the left 90 is in an unlocked position,
while the locking ring 12 within the screw 10 on the right 92 is in
a locked position. The head 24 of the screw 10 can be receivable in
the through-hole 70 of the plate 14. For example, the upper portion
76 of the through-hole 70 can be large enough to allow the screw 10
to pass through when the locking ring 12 is in an unlocked
position. For example, a diameter of the head 24 of the screw 10
can be smaller than a diameter of the upper portion 76 of the
through-hole 70. The lower portion 80 of the through-hole 70
preferably limits the screw 10 from passing completely through the
through-hole 70. For example, a diameter of the lower portion 80 of
the through-hole 70 can be smaller than a diameter of the lower
portion 30 of the screw 10.
[0035] In certain embodiments, the lower portion 80 of the
through-hole 70 and/or the lower portion 30 of the screw 10 are
curved. The lower portion 30 of the screw 10 can rest against the
lower portion 80 of the through-hole 70 to press the plate 14
against the vertebrae when the screw 10 is screwed into the
vertebrae. At least a portion of the upper portion 76 and/or lower
portion 80 of the through-hole 70 can extend beyond the groove 78
of the through-hole 70 to form the groove 78. For example, a
diameter of the upper portion 76 and/or lower portion 80 of the
through-hole 70 can be smaller than a diameter of the groove 78 of
the through-hole 70. In certain embodiments, a diameter of the
lower portion 80 of the through-hole 70 is smaller than a diameter
of the groove 78 and/or the upper portion 76 of the through-hole
70. In the unlocked position, the locking ring 12 is outside the
groove 78 of the through-hole 70. In the locked position, the
locking ring 12 is at least partially within the groove 78 of the
through-hole 70. When the locking ring 12 is in the locked
position, the locking ring 12 substantially limits the screw 10
from backing out of the through-hole 70 of the plate 14. In certain
embodiments, the locking ring 12 does not touch a surface of the
through-hole 70, and in other embodiments, the locking ring 12 may
touch a surface of the through-hole 70. If the screw 10 at least
partially backs out of the plate 14, the locking ring 12 may
impinge on the upper portion 76 of the through-hole 70. By
impinging on the upper portion 76 of the through-hole 70, the
locking ring 12 substantially limits the screw 10 from backing out.
In certain embodiments, the locking ring 12 can be rotated between
the locked position and the unlocked position so as to allow the
screw 10 to be removable after the screw 10 has been inserted into
the plate 14.
[0036] FIG. 9 illustrates a top view of a plate 14 with screws 10
inserted into two through-holes 70. The locking ring 12 within the
screw 10 on the left 90 is in an unlocked position, while the
locking ring 12 within the screw 10 on the right 92 is in a locked
position. The locking ring 12 in an unlocked position is not within
the groove 78 of the through-hole 70. The locking ring 12 in a
locked position is at least partially within the groove 78 of the
through-hole 70. The locking ring 12 in a locked position is also
at least partially under the upper portion 76 of the through-hole
70. In some embodiments, the locking ring 12 is placed within the
groove 78 of the screw 10 prior to the screw 10 being inserted into
the through-hole 70. In other embodiments, the locking ring 12 is
placed within the groove 78 of the screw 10 when the screw 10 is at
least partially inserted into the through-hole 70. In even further
embodiments, the locking ring 12 is placed within the groove 78 of
the screw 10 after the screw 10 is fully inserted in the
through-hole 70.
[0037] FIGS. 10 and 11 illustrate additional embodiments of a
locking ring 12 and a screw 10, respectively. The locking ring 12
can include an anterior surface 46 and a posterior surface 48
(similar to that shown in FIG. 6). In certain embodiments, the
locking ring 12 has a first protrusion 102 on the anterior surface
46 and/or the inner curved surface 44 of the locking ring 12. The
first protrusion 102 can have a means to assist in rotation of the
locking ring 12 (e.g. a hole 40, etc.). At least a portion of the
upper portion 26 and/or the groove 28 of the head 24 can have a
first notch 114 to form a c-shape. The first protrusion 102 can
reside and/or be within the first notch 114 when the ring 12 is in
the groove 28. As illustrated in FIGS. 12A-D, the first protrusion
102 can restrict the rotational movement of the locking ring 12.
When the first protrusion 102 is at one end of the first notch 114,
the locking ring 12 can be in an unlocked position, as illustrated
in FIGS. 12A and 12C. When the first protrusion 102 is at the other
end of the first notch 114, the locking ring 12 can be in a locked
position, as illustrated in FIGS. 12B and 12D, extending outwardly
beyond the lower portion 30 of the head 24.
[0038] In certain embodiments, the locking ring 12 has a second
protrusion 104 on the inner curved surface 44. At least a portion
of the groove 28 of the head 24 can have a second notch 112 (see
FIG. 11). In an unlocked position, the second protrusion 104 is at
least partially within the second notch 112. When the second
protrusion 104 is at least partially within the second notch 112,
the locking ring 12 is at least partially restricted from rotating
out of the unlocked position. In certain embodiments, the torque
required to rotate the locking ring 12 when the second protrusion
104 is at least partially within the second notch 112 is greater
than the torque required to rotate the locking ring 12 when the
second protrusion 104 is not within the second notch 112.
Advantageously, the rotational restriction of the locking ring 12
due to the second protrusion 104 being at least partially within
the second notch 112 at least partially limits the locking ring 12
from rotating during insertion of the screw 10 into the plate 14.
However, in certain embodiments, the rotational restriction of the
locking ring 12 due to the second protrusion 104 being at least
partially within the second notch 112 is less than the rotational
force that a tool can exert so that the locking ring 12 can be
rotated with the tool. In certain embodiments, the locking ring 12
has a second protrusion 104 while the groove 28 of the head 24 does
not have a second notch 112.
[0039] In a locked position, the second protrusion 104 is at least
partially within the first notch 114 and outside the second notch
112, as illustrated in FIGS. 12B and 12D. The second protrusion 104
at least partially restricts the locking ring 12 from rotating into
an unlocked position. In certain embodiments, the second protrusion
104 is at one end of the first notch 114 and the first protrusion
102 is at the other end of the first notch 114. Advantageously,
when the second protrusion 104 and the first protrusion 102 are at
opposite ends of the first notch 114, the locking ring 12 is at
least partially restricted from rotating in either direction. In
certain embodiments, the rotational restriction of the locking ring
12 due to the second protrusion 104 at least partially within the
first notch 114 is less than that required to rotate the locking
ring 12 with a tool. Advantageously, by being able to unlock the
locking ring 12 after the locking ring 12 has been placed into a
locked position, the screw 10 is able to be removed after the screw
10 and plate 14 have been installed. In certain embodiments, the
second protrusion 104 can be on the posterior surface 46 and/or the
anterior surface 48 of the locking ring 12, and the second notch
112 can be on the upper portion 26 and/or the lower portion 30 of
the head 24, respectively. In further embodiments, the groove 28
includes the second protrusion 104 and the locking ring 12 includes
the second notch 112. In some embodiments, the second protrusion
104 is within the second notch 112 when in a locked position. While
some preferred configurations have been described in detail above,
other configurations for releasably holding the locking ring in
unlocked and/or locked positions are possible and can be used.
[0040] In certain embodiments, the screw 10 can be at an angle
within the through-hole 70 of the plate 14, as illustrated in FIG.
13. For example, the screw 10 can be screwed into a vertebral body
at an angle non-perpendicular to the plate 14. Advantageously, this
allows more options of placement of screws 10 in the vertebrae. In
certain embodiments, a thickness of the groove 78 of the
through-hole 70 is large enough that when the locking ring 12 is
rotated into a locked position, the locking ring 12 can at least
partially be within the groove 78. The locking ring 12 in FIG. 13
is illustrated in a locked position. When the screw 10 is at an
angle, the locking ring 12 may also be at an angle. A larger
thickness of the groove 78 preferably allows a locking ring 12 at
an angle to at least partially reside within the groove 78. If the
thickness of the groove 78 is not large enough to accommodate the
locking ring 12 at a particular angle, the locking ring 12 may
impinge on the upper portion 76 and/or the lower portion 80 of the
through-hole 70 and not be able to be rotated into a locked
position.
[0041] The bone plate systems discussed above can be used to fix
adjacent vertebrae. FIG. 14 shows one embodiment of a bone plate
system implanted in vertebrae of a patient. For example, the plate
14 can be positioned on the anterior surface of at least two
adjacent vertebral bodies. At least one through-hole 70 can be
positioned over a first vertebral body and a second through-hole 70
can be positioned over a second vertebral body. A screw 10 can be
inserted through one of the through-holes 70 into the first
vertebral body and a second screw 10 can be inserted through
another through-hole 70 into the second vertebral body. The
threaded body of the screws 10 can engage with the vertebral
bodies. A locking ring 12 can be positioned into a locking
position. For example, the locking ring can be rotated so that the
locking ring 12 is within the groove 28 of the head 24 of at least
one of the screws 10, and the locking ring 12 is positioned at
least partially within a groove 78 of one of the through-holes 70
to limit the screw 10 backing out of the through-hole 70.
[0042] A number of surgical methods can be used to implant bone
plate systems. For example, several surgical methods are described
in U.S. Pat. No. 7,674,279, herein incorporated by reference in its
entirety. For example, the patient can be placed on the operating
room table in the supine position with the head in slight extension
and slight rotation opposite the side of incision.
[0043] After decompression and interbody grafting procedures have
been completed, anterior osteophytes can be removed to provide a
contoured contact surface for positioning the plate 14. The plate
14 can be selected so that the edges do not extend over adjacent
disc spaces. The plate 14 can be pre-contoured with lordotic
curvature to minimize the amount of intra-operative contouring
required. A plate bender can also used for contouring.
[0044] The plate 14 can then be positioned over vertebral bodies
using a plate holder, and then the plate 14 can be confirmed that
it is properly aligned in mediolateral and caudocranial position.
The position of the plate 14 can be temporary fixed using pins
(e.g., temporary pins, etc.). The pins can be inserted with a tool
(e.g., screwdriver, etc.). The pins can be inserted through any of
the screw holes and can provide stability during placement of the
screw 10.
[0045] An awl may be used to create a pilot hole before inserting
the screw 10. The awl is placed in one of the through-holes 70 of
the plate 14. In certain embodiments, the awl is placed at an angle
of up to about 14.degree. from a perpendicular axis to the plate
14. The awl is pressed and rotated in the bone until a depth has
been reached. For example, the awl can be inserted until it has
bottomed out. In certain embodiments, the awl can provide a depth
of about 10 mm. Alternatively, a drill guide and drill can be used
to create a pilot hole. The drill guide can be attached to the
plate 14 and the drill can create a pilot hole. In certain
embodiments, the drills are about 12, 14, or 16 mm in length. The
screws 10 can be self-tapping and/or self-drilling screws so that
tapping may not be used. In some cases, where the bone is hard
cortical bone, tapping may still be used. In certain embodiments,
the tap is provided at a depth of about 10 mm. In certain
embodiments, the self-tapping or self-drilling screws have a length
of about 12, 14, 16, or 18 mm with a diameter of about 4.0 mm. An
about 4.5 mm diameter screw can also be used if there is additional
bone purchase. The above screw lengths are measure from under the
head 24 of the screw 10 to the end of the distal end 20 of the
screw 10. In certain embodiments, the screws are inserted using a
hex screwdriver.
[0046] The plate 14 may vary in size. For example, the length and
level number of the plate 14 may vary. The level number of the
plate 14 indicates the number of vertebral body connections made by
plate 14. In some embodiments, a 1-level plate 14 preferably has a
length from about 20 mm to about 32 mm and connects two vertebral
bodies. In some embodiments, a 2-level plate 14 preferably has a
length from about 37 mm to about 55 mm and connects three vertebral
bodies. In some embodiments, a 3-level plate 14 preferably has a
length from about 54 mm to about 75 mm and connects four vertebral
bodies. In some embodiments, a 4-level plate 14 preferably has a
length from about 69 mm to about 89 mm and connects five vertebral
bodies.
[0047] The screw 10 can be inserted into vertebrae until it rests
firmly inside the through-hole 70 of the plate 14. Once the screws
10 have been seated, positioned and tightened, then locking ring 12
can be rotated to a locked position. If desired, the screws 10 can
be subsequently removed by rotating the locking ring 12 to an
unlocked position and removing the screws 10. In certain
embodiments, the screws 10 can be repositioned, tightened and then
locked again without mechanically weakening the locking mechanism.
Visual and radiographic confirmation of plate, screw and bone graft
placement can be done, and the incision can then be closed.
[0048] The various screws and methods described above provide a
number of ways to carry out some preferred embodiments of the
invention. Of course, it is to be understood that not necessarily
all objectives or advantages described may be achieved in
accordance with any particular embodiment described herein. Thus,
for example, those skilled in the art will recognize that the
devices and systems may be made and the methods may be performed in
a manner that achieves or optimizes one advantage or group of
advantages as taught herein without necessarily achieving other
objectives or advantages as may be taught or suggested herein.
[0049] Furthermore, the skilled artisan will recognize the
interchangeability of various features from different embodiments.
Similarly, the various components, features and steps discussed
above, as well as other known equivalents for each such component,
feature or step, can be mixed and matched by one of ordinary skill
in this art to make devices and systems and perform methods in
accordance with principles described herein.
[0050] Although the invention has been disclosed in the context of
some embodiments and examples, it will be understood by those
skilled in the art that the invention extends beyond these
specifically disclosed embodiments to other alternative embodiments
and/or uses and obvious modifications and equivalents thereof.
Accordingly, the invention is not intended to be limited by the
specific disclosures of preferred embodiments herein.
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