U.S. patent application number 14/086118 was filed with the patent office on 2014-03-27 for bone plate with retainer and stop for screw lock.
This patent application is currently assigned to Spinal U.S.A.. The applicant listed for this patent is Spinal U.S.A.. Invention is credited to Cyrus Ghavam, Jeffrey Johnson, Adam Lewis, Morris Seymour, Lawrence Walker.
Application Number | 20140088653 14/086118 |
Document ID | / |
Family ID | 50072092 |
Filed Date | 2014-03-27 |
United States Patent
Application |
20140088653 |
Kind Code |
A1 |
Walker; Lawrence ; et
al. |
March 27, 2014 |
Bone Plate With Retainer and Stop for Screw Lock
Abstract
A bone plate, having a bone screw and a rotatable lock for
retaining the bone screw in place, includes a retainer element
and/or a stop element. The retainer element inhibits the lock from
being pushed off of the bone plate, while the stop element limits
the rotational range of motion of the lock.
Inventors: |
Walker; Lawrence; (Madison,
MS) ; Johnson; Jeffrey; (Flowood, MS) ;
Seymour; Morris; (Huntsville, AL) ; Lewis; Adam;
(Jackson, MS) ; Ghavam; Cyrus; (Huntsville,
AL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Spinal U.S.A. |
Pearl |
MS |
US |
|
|
Assignee: |
Spinal U.S.A.
Pearl
MS
|
Family ID: |
50072092 |
Appl. No.: |
14/086118 |
Filed: |
November 21, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12567978 |
Sep 28, 2009 |
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14086118 |
|
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61101737 |
Oct 1, 2008 |
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Current U.S.
Class: |
606/289 |
Current CPC
Class: |
A61B 17/8052 20130101;
A61B 17/8042 20130101; A61B 17/7059 20130101 |
Class at
Publication: |
606/289 |
International
Class: |
A61B 17/80 20060101
A61B017/80 |
Claims
1. A bone plate comprising: a plate formed of a biocompatible
material and having an upper surface; at least one screw hole
formed in the plate; and a stop element positioned on the plate
upper surface; wherein, when a rotatable screw lock is rotatably
mounted to the upper surface of the plate, at a position relative
to the at least one screw hole so that, in a first unlocked
position the screw lock does not impede passage of a bone screw
through the at least one screw hole, and in a second locked
position the screw lock does impede passage of a bone screw through
the at least one screw hole, the stop element prevents the screw
lock from complete rotation.
2. A bone plate according to claim 1, further comprising: a
rotatable screw lock mounted to the plate upper surface, the screw
lock including a central portion and a laterally extending flange,
the screw lock rotatable from said first unlocked position to said
second locked position.
3. A bone plate according to claim 2, further comprising: a
retainer element positioned adjacent to the screw hole and forming
a gap between the retainer and the plate upper surface; wherein,
when the rotatable screw lock is in the first unlocked position,
the screw lock does not impede passage of a bone screw through the
at least one screw hole, and, when the rotatable screw lock is in
the second locked position, the screw lock does impede passage of a
bone screw through the at least one screw hole, a portion of the
screw lock positioned in the gap when in the second position.
4. A bone plate according to claim 1, further comprising: a
retainer element positioned adjacent to the screw hole and forming
a gap between the retainer and the plate upper surface; wherein,
when the rotatable screw lock is in the first unlocked position,
the screw lock does not impede passage of a bone screw through the
at least one screw hole, and, when the rotatable screw lock is in
the second locked position, the screw lock does impede passage of a
bone screw through the at least one screw hole, a portion of the
screw lock positioned in the gap when in the second position.
5. A bone plate according to claim 4, wherein the stop is
positioned immediately adjacent to the retainer.
6. A bone plate according to claim 4, wherein the retainer includes
a laterally extending portion having a bottom surface, the bottom
surface spaced from the top surface of the plate, the gap located
between the laterally extending portion bottom surface and the
plate upper surface.
7. A bone plate according to claim 1, wherein the stop element
includes a vertically extending wall.
8. A bone plate according to claim 1, wherein the stop is
positioned remotely from the at least one screw hole.
9. A bone plate comprising: a plate formed of a biocompatible
material and having an upper surface; at least one screw hole
formed in the plate; and a retainer element positioned adjacent to
the screw hole and forming a gap between the retainer and the plate
upper surface; and wherein, when a rotatable screw lock is
rotatably mounted to the upper surface of the plate, at a position
relative to the at least one screw hole so that, in a first
unlocked position the screw lock does not impede passage of a bone
screw through the at least one screw hole, and in a second locked
position the screw lock does impede passage of a bone screw through
the at least one screw hole, the screw lock passes under the
retainer element when moving between the first and second
positions.
10. A bone plate according to claim 9, further comprising: a
rotatable screw lock mounted to the plate upper surface, the screw
lock including a central portion and a laterally extending flange,
the screw lock rotatable from said first unlocked position to said
second locked position.
11. A bone plate according to claim 9, wherein the retainer
includes a laterally extending portion having a bottom surface, the
bottom surface spaced from the top surface of the plate, the gap
located between the laterally extending portion bottom surface and
the plate upper surface.
Description
[0001] This application is a Continuation of, and claims priority
under 35 U.S.C. .sctn.120 to, U.S. patent application Ser. No.
12/567,978, filed 28 Sep. 2009, which claimed priority under 35
U.S.C. .sctn.119 to U.S. provisional patent application no.
61/101,737, filed 01 Oct. 2008, the entireties of which are
incorporated by reference herein.
BACKGROUND
[0002] 1. Field of Endeavor
[0003] The present invention relates to devices, systems, and
processes useful as bone plates, and more specifically to
improvements in such plates fitted with screw locks.
[0004] 2. Brief Description of the Related Art
[0005] U.S. Pat. No. D592,946 relates to a design of a rotatable
lock for the bone screws used to hold bone plates to a bone, such
as anterior cervical plates used in spinal surgeries. U.S. Patent
Application Publication No. 2008/0091206, "Bone Plate", describes
similar bone plates including rotatable screw locks. The entirety
of each of these documents is incorporated by reference herein.
[0006] While the bone plates described in these patent documents
perform well, in some circumstances the bone screws can back out of
the bone to such an extent that the bone screw lock, which had been
rotated over the head of the bone screw, is flexed upwards. Such
flexing can cause damage to the bone screw lock, risking fracture
of the lock. In addition, one difficulty that can arise with the
use of such rotatable bone screw locks is that the practitioner
does not have a way of knowing when the lock has been rotated the
correct amount to adequately block the underlying bone screw from
backing out, other than mere visual inspection.
[0007] There remains a need for improvements in bone screw locks
which can address these and other issues.
SUMMARY
[0008] According to a first aspect of the invention, a bone plate
comprises a plate formed of a biocompatible material and having an
upper surface, at least one screw hole formed in the plate, and a
stop element positioned on the plate upper surface, wherein, when a
rotatable screw lock is rotatably mounted to the upper surface of
the plate, at a position relative to the at least one screw hole so
that, in a first unlocked position the screw lock does not impede
passage of a bone screw through the at least one screw hole, and in
a second locked position the screw lock does impede passage of a
bone screw through the at least one screw hole, the stop element
prevents the screw lock from complete rotation.
[0009] According to another aspect of the present invention, a bone
plate comprises a plate formed of a biocompatible material and
having an upper surface, at least one screw hole formed in the
plate, and a retainer element positioned adjacent to the screw hole
and forming a gap between the retainer and the plate upper surface,
and wherein, when a rotatable screw lock is rotatably mounted to
the upper surface of the plate, at a position relative to the at
least one screw hole so that, in a first unlocked position the
screw lock does not impede passage of a bone screw through the at
least one screw hole, and in a second locked position the screw
lock does impede passage of a bone screw through the at least one
screw hole, the screw lock passes under the retainer element when
moving between the first and second positions.
[0010] Still other aspects, features, and attendant advantages of
the present invention will become apparent to those skilled in the
art from a reading of the following detailed description of
embodiments constructed in accordance therewith, taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention of the present application will now be
described in more detail with reference to exemplary embodiments of
the apparatus and method, given only by way of example, and with
reference to the accompanying drawings, in which:
[0012] FIG. 1 illustrates a top plan view of a first exemplary
embodiment of a bone plate in accordance with the present
invention;
[0013] FIG. 2 illustrates an enlarged, top plan view of right side
portions of the device illustrated in FIG. 1, taken at line F-F in
FIG. 3;
[0014] FIG. 3 illustrates a cross-sectional view of the device of
FIG. 1, taken at line A-A;
[0015] FIG. 4 illustrates a cross-sectional view of the device of
FIG. 1, taken at line C-C;
[0016] FIG. 5 illustrates a cross-sectional view of the device of
FIG. 1, taken at line D-D in FIG. 2;
[0017] FIG. 6 illustrates a cross-sectional view of the device of
FIG. 1, taken at line B-B in FIG. 3;
[0018] FIG. 7 illustrates a cross-sectional view of the device of
FIG. 1, taken at line E-E in FIG. 2;
[0019] FIG. 8 illustrates a top plan view of the embodiment of FIG.
1, showing screw locks;
[0020] FIG. 9 illustrates a cross-sectional view of the device of
FIG. 1, taken at line G-G in FIG. 8;
[0021] FIG. 10 illustrates a top, right, front perspective view of
right side portions of FIG. 11, of the device of FIG. 8;
[0022] FIG. 11 illustrates a top, right, front perspective view of
the device of FIG. 8;
[0023] FIG. 12 illustrates another top, right, front perspective
view of the device of FIG. 8, with the screw locks oriented in
their `unlocked` positions';
[0024] FIG. 13 illustrates the top, right, front perspective view
of the device of FIG. 8, with the screw locks oriented in their
`locked` positions';
[0025] FIG. 14 illustrates a top plan view of the device of FIG. 8,
with the screw locks oriented in their `locked` positions; and
[0026] FIG. 15 illustrates a top, right, rear perspective view of
right side portions of the device of FIG. 8, with the screw locks
oriented in their `locked` positions.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0027] Referring to the drawing figures, like reference numerals
designate identical or corresponding elements throughout the
several figures.
[0028] The aforementioned two patent document describe bone plates
and locks for the screws of bone plates; as those of ordinary skill
in the art are well familiar with bone plates, screws for bone
plates, and locks for the screws of bone plates, the details of
those devices will not be included herein.
[0029] In general terms, in addition to the various features
described in the two aforementioned patent documents, in accordance
with principles of the present invention, a bone plate can be
provided with a stop, a retainer, or both, for each one or more of
the bone screw locks (also called a `bow-tie rivet` herein). In
essence, the stop is sized and positioned so that, when the bow-tie
rivet is rotated in one direction, e.g., clockwise, the leading
edge of the rivet hits the stop and prevents further rotational
motion of the rivet. The lower surface of the retainer is spaced
from the surface of the plate a distance sufficient to permit
portions of the rivet to pass under the retainer as the rivet is
rotated (e.g., clockwise); when the rivet's rotational motion ends,
optionally because of the stop S, a portion of the rivet is still
under the retainer R, which thus inhibits the rivet from popping
off of the plate. Thus, by providing a stop to one side of the
plate, when the practitioner turns the rivet, e.g., to 90 degrees,
the rivet will hit against the stop and the practitioner thus knows
to stop turning the rivet. Furthermore, the retainer can be
provided so that when the rivet turns, it will stay under the
retainer, so the rivet is inhibited or prevented from coming off of
the plate.
[0030] The positions of the retainer and the stop, relative to the
rotatable lock and to the screw holes, can be tailored to the
particular application. Furthermore, the locations of the retainer
and the stop can be swapped, that is, can be moved to accommodate
clockwise or counterclockwise rotation of the lock. Furthermore,
while the lock is illustrated as being positioned so that its top
surface is above the upper surface of the bone plate, the lock can
alternatively be recessed in the plate; in this configuration, the
stop can be formed as a shoulder in the plate itself, rather than
as an element extending above the plate's surface, and the retainer
can be suitably lowered. Further optionally, the rotatable lock
itself can be made asymmetrical, so that one lateral side of the
lock is shorter than the other, so that the shorter side would not
be impeded by the stop, yet still restrained by the retainer. Yet
further alternatively, the stop and retainer can be either
co-located, or incorporated into a single element that both
overhangs the screw hole, including a space for a portion of the
lock to reside, yet also includes a portion that blocks further
rotational motion of the lock. All of the devices and components
described herein are formed of biocompatible, implantable materials
typically used for bone plates.
[0031] Turning now to the several drawing figures, exemplary bone
plates embodying principles of the present invention are
illustrated. In the top plan views of FIGS. 1 and 2, a bone plate
10 includes a generally flat body 12, which can include curvatures
depending on the particular use for which the plate will be
employed. The plate 10 includes at least one, and advantageously
numerous screw holes 14 which pass entirely through the body 12
from the top to the bottom surfaces, and are sized and otherwise
configured to receive a bone screw in each of the holes. Further
optionally, the plate 10 can include one or more (one being
illustrated) additional holes 16, for reducing the weight of the
plate, among other purposes. One or more holes or bores 18 are
formed in the body 12 to receive portions of a rotatable screw
lock, described elsewhere herein and in the aforementioned U.S.
patent documents; the holes 18 are positioned adjacent to at least
one of the screw holes 14 so that when a screw lock is mounted in
the hole 18, the screw lock can lock the head of a screw positioned
in the hole 14.
[0032] As discussed above, the plate 10 includes a stop 20, a
retainer 22, or both, in proximity to one or more of the holes 14.
In the embodiment illustrated in FIG. 1, for each of the two pairs
of bone screw holes on the left and right sides of the plate 10, a
stop 20 is positioned immediately adjacent to one screw hole and a
retainer 22 is positioned adjacent to the other screw hole of the
pair. As a single bone screw lock is used to secure the bone screws
in each pair of bone screw holes in this embodiment, the stop 20
and the retainer 22 are provided for each rotatable bone screw
lock. According to other exemplary embodiments, more than one
retainer, stop, or both, can be provided for each bone screw lock,
regardless of the number of bone screws the particular lock secures
to the plate 10.
[0033] FIGS. 3 and 4 illustrate a cross-sectional view, taken at
lines A-A and C-C in FIGS. 1, respectively, and show that the stop
20 need not extend far from the body 12 in order to prevent a
rotatable bone screw lock from moving. Additionally, FIGS. 3 and 4
illustrate the overhanging feature of the retainer, which can
inhibit or prevent a bone screw lock from popping off of the body
12.
[0034] FIG. 5 illustrates a cross-sectional view, taken at line D-D
of FIG. 2, of an exemplary retainer 22. The retainer 22 includes an
upstanding portion 24 which is attached to the body 12 of the plate
10, and a laterally extending portion 26 which is attached to the
upstanding portion 24. While the embodiment illustrated in FIG. 5
includes portions 24, 26 being integral with each other and with
the body 12, other exemplary embodiments include these portions
which are formed of one or more separate pieces which are joined
together and joined to the body 12. The laterally extending portion
has a bottom surface 28 which at least in part faces the top
surface of the body 12 and defines a gap 30 between the bottom
surface of the laterally extending portion and the top of the body
12. The gap 30 is sized and shaped to receive a portion of a bone
screw lock therein and to thus inhibit or prevent the bone screw
lock from moving vertically away from the body 12.
[0035] FIGS. 6 and 7 illustrate further cross-sectional views of
the plate 10. As illustrated in FIG. 7, the stop 20 advantageously
includes a vertically extending wall 32 which provides a
well-defined position at which a bone screw lock will stop when
rotated against the stop 20.
[0036] FIG. 8 illustrates a top plan view of the bone plate 10,
with an exemplary rotatable bone screw lock 40 mounted to the body
12 at the hole 18. According to preferred embodiments, the lock 40
is configured and positioned on the body 12 in the manner described
in the aforementioned two U.S. patent documents. The lock 40
includes a narrow central portion 42 and at least one, preferably
two, and alternatively more than two, flared end portions 44 which
extend outward from the central portion 42. As will be described in
greater detail below, the configuration of the flared end
portion(s) 44, the stop 20, and the retainer 22 are mutually
dependent, and are constructed so that the lock 40 has at least two
alternative rotary positions: a first position at which at least
one of the adjacent bone screw holes 14 are unobstructed, so that a
bone screw can be positioned in the bone screw hole; and a second
position at which at least one of the flared end portions 42
overlies and obstructs the bone screw hole. In the second position,
one of the flared end portions bears against the stop 20, and/or
one of the flared end portions is at least partially under the
laterally extending portion of a retainer 22 and in the gap 30. The
lock 40 advantageously includes an opening 46 in the central
portion 42 which can be configured to accept a torque driving tool
(e.g., screwdriver, not illustrated) to assist the practitioner in
rotating the lock 40 between its various rotary positions.
[0037] FIG. 9, which is a cross-sectional view taken at line G-G in
FIG. 8, illustrates the top surface 50 the lock 40, a portion of
which will be trapped beneath the laterally extending portion 30
when in the aforementioned second position. While the top surface
50 is illustrated as being convex and slightly dome-shaped, the top
surface can be other shapes as well. The lock 40 optionally
includes a vertically extending post 48, optionally formed of a
deformable material, so that the lock can be rotatably secured to
the plate body 12.
[0038] FIGS. 10-15 illustrate several perspective and plan views of
the plate 10, with locks 40 in both the first (open) and second
(locking) positions, and illustrate exemplary positions of the
flanges 44 of the locks relative to the stop 20 and the retainer
22. FIGS. 10 and 11 illustrate perspective views of the plate 10
having both a stop 20 and a retainer 22, and a rotatable bone screw
lock 40 rotated into an unlocked positioned, that is, the flanges
44 of the lock do not obstruct a bone screw hole 14. FIG. 12
illustrates a similar view, with two locks 40 in the same, unlocked
orientation. FIG. 13 illustrates the same view as FIG. 12, but with
the locks 40 rotated clockwise (as seen from above) into locking
positions, that is, with the flanges 44 at least partially covering
a hole 14. As can be seen in FIGS. 13-15, at least one of the
flanges 44 is positioned under the laterally extending portion 26
of the retainer 22, and in the gap 30, when in the second position.
Additionally, when provided with a stop 20, one of the flanges 44
abuts against the stop, and more particularly against the wall 32
in this embodiment. The stop 20 is thus advantageously positioned
so that, when a flange 44 meets the stop, another portion of the
lock 40, e.g., a flange of the lock, is under the laterally
extending portion 26 and in the gap 30. The stop 20 can be
eliminated from the plate 10, if desired.
[0039] According to further embodiments, the stop 20 and the
retainer 22 can be located immediately adjacent to each other or
integrated into a single structure, and the combination can be
positioned as the retainers illustrated herein. Further optionally,
the bottom surface 28 can be angled so that a flange 44 can enter
into the gap 30, and upon further rotation of the lock 40 into the
gap, the top surface 50 of the lock bears against the bottom
surface 28 and locks the flange to the retainer 22. Yet further
optionally, the bottom surface 28 and top surface 50 can be formed
with cooperating snap-fit structures, such as one or more ridges
and grooves, so that when the flange 44 is rotated into the gap 30
and the top surface 50 and bottom surface 28 bear against each
other, the ridge(s) and groove(s) can snap together, thus forming a
releasable lock.
[0040] While the invention has been described in detail with
reference to exemplary embodiments thereof, it will be apparent to
one skilled in the art that various changes can be made, and
equivalents employed, without departing from the scope of the
invention. The foregoing description of the preferred embodiments
of the invention has been presented for purposes of illustration
and description. It is not intended to be exhaustive or to limit
the invention to the precise form disclosed, and modifications and
variations are possible in light of the above teachings or may be
acquired from practice of the invention. The embodiments were
chosen and described in order to explain the principles of the
invention and its practical application to enable one skilled in
the art to utilize the invention in various embodiments as are
suited to the particular use contemplated. It is intended that the
scope of the invention be defined by the claims appended hereto,
and their equivalents. The entirety of each of the aforementioned
documents is incorporated by reference herein.
* * * * *