U.S. patent application number 15/872549 was filed with the patent office on 2019-07-18 for expandable interbody spinal fusion device capable of being deployed endoscopically.
The applicant listed for this patent is Loubert S. Suddaby. Invention is credited to Loubert S. Suddaby.
Application Number | 20190216613 15/872549 |
Document ID | / |
Family ID | 66996671 |
Filed Date | 2019-07-18 |
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United States Patent
Application |
20190216613 |
Kind Code |
A1 |
Suddaby; Loubert S. |
July 18, 2019 |
EXPANDABLE INTERBODY SPINAL FUSION DEVICE CAPABLE OF BEING DEPLOYED
ENDOSCOPICALLY
Abstract
An expandable interbody spinal fusion device, including a
superior component an inferior component and an expansion
mechanism. The expansion mechanism including a threaded rod, a
threaded collar operatively arranged to engage with the threaded
rod and axially translate in a first axial direction, a fixed
collar secured about the threaded rod, a first arm pivotably
secured to the fixed collar, and a first strut pivotably secured to
the first arm and the threaded collar.
Inventors: |
Suddaby; Loubert S.;
(Orchard Park, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Suddaby; Loubert S. |
Orchard Park |
NY |
US |
|
|
Family ID: |
66996671 |
Appl. No.: |
15/872549 |
Filed: |
January 16, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/4455 20130101;
A61F 2/4425 20130101; A61F 2/442 20130101; A61F 2002/30329
20130101; A61F 2002/30579 20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. An expandable interbody spinal fusion device, comprising: a
superior component; an inferior component; an expansion mechanism
comprising: a threaded rod; a threaded collar operatively arranged
to engage with the threaded rod and axially translate in a first
axial direction; a fixed collar secured about the threaded rod; a
first arm including a first end and a second end, the first end
pivotably secured to the fixed collar; and, a first strut pivotably
secured to: the first arm at a point intermediate the first and
second ends; and, the threaded collar.
2. The expandable interbody spinal fusion device of claim 1 wherein
the first arm is pivotably secured to a superior plate.
3. The expandable interbody spinal fusion device of claim 1 wherein
the expansion mechanism further comprises: a second arm pivotably
secured to an inferior plate and the fixed collar; and, a second
strut pivotably secured to the second arm and the threaded
collar.
4. The expandable interbody spinal fusion device of claim 3 wherein
the expansion mechanism further comprises: a superior plate
arranged to pivotably connect with the first arm, wherein the
threaded rod is rotated in a first rotational direction to displace
the superior plate in a first direction orthogonal an axis of
rotation of the threaded rod, and displace the inferior plate in a
second direction orthogonal to the axis of rotation and opposite
the first direction.
5. The expandable interbody spinal fusion device of claim 4 wherein
the superior plate has a first surface arranged to contact and
displace the superior component, and the inferior plate has a first
surface arranged to contact and displace the inferior
component.
6. The expandable interbody spinal fusion device of claim 1 wherein
the first arm comprises a first recess operatively arranged to
receive the first strut when the expandable interbody spinal fusion
device is in a collapsed state.
7. The expandable interbody spinal fusion device of claim 6 wherein
the second arm comprises a second recess operatively arranged to
receive the second strut when the expandable interbody spinal
fusion device is in a collapsed state.
8. The expandable interbody spinal fusion device of claim 1 wherein
a locking mechanism is positioned on the threaded rod adjacent to
the fixed collar in the first direction or second direction such
that the fixed collar is prevented from being displaced in the
first direction or second direction, respectively.
9. The expandable interbody spinal fusion device of claim 8 wherein
the locking mechanism is a lock washer, a crimp ring retainer, or a
serrated lock washer.
10. An expandable interbody spinal fusion device, comprising: a
superior component; an inferior component; a first expansion
mechanism comprising: a threaded rod; a superior plate; an inferior
plate; a first threaded collar operatively arranged to engage with
the threaded rod; a first fixed collar fixedly arranged about the
threaded rod; a first arm pivotably secured to the superior plate
and the first fixed collar, the first arm comprising a first
recess; a first strut pivotably secured to the first arm and the
first threaded collar, the first recess operatively arranged to
receive the first strut; a second arm pivotably secured to the
inferior plate and the first fixed collar, the second arm
comprising a second recess; and, a second strut pivotably secured
to the second arm and the first threaded collar, the second recess
operatively arranged to receive the second strut, wherein the
threaded rod is rotated about a first axis of rotation in a first
rotational direction to displace the superior component in a first
direction orthogonal to the first axis of rotation.
11. The expandable interbody spinal fusion device of claim 10
wherein the first expansion mechanism further comprises: a second
threaded collar operatively arranged to engage with the threaded
rod; a second fixed collar arranged about the threaded rod; a third
arm pivotably secured to the superior plate and the second fixed
collar; a third strut pivotably secured to the third arm and the
second threaded collar; a fourth arm pivotably secured to the
inferior plate and the second fixed collar; and, a fourth strut
pivotably secured to the fourth arm and the second threaded
collar.
12. The expandable interbody spinal fusion device of claim 11
wherein the third arm comprises a third recess operatively arranged
to receive the third strut, the fourth arm comprises a fourth
recess operatively arranged to receive the fourth strut.
13. The expandable interbody spinal fusion device of claim 10
wherein a locking mechanism is positioned on the threaded rod
adjacent to the first fixed collar and the second fixed collar such
that the first fixed collar is prevented from being displaced in a
first axial direction and the second fixed collar is prevented from
being displaced in a second axial direction opposite the first
axial direction.
14. The expandable interbody spinal fusion device of claim 13
wherein the locking mechanism is a lock washer, crimp ring
retainer, or a serrated lock washer.
15. An expandable interbody spinal fusion device, comprising: a
superior component; an inferior component; and, an expansion
mechanism comprising: a superior plate; an inferior plate; a
threaded rod; a first threaded collar operatively arranged to
engage with the threaded rod; a second threaded collar operatively
arranged to engage with the threaded rod; a fixed collar arranged
about the threaded rod; a first arm pivotably secured to the
superior plate and the fixed collar; a first strut pivotably
secured to the first arm and the first threaded collar; a second
arm pivotably secured to the inferior plate and the fixed collar; a
second strut pivotably secured to the second arm and the first
threaded collar; a third arm pivotably secured to the superior
plate and the fixed collar; a third strut pivotably secured to the
third arm and the second threaded collar; a fourth arm pivotably
secured to the inferior plate and the fixed collar; and, a fourth
strut pivotably secured to the fourth arm and the second threaded
collar, wherein the threaded rod is rotated in a first rotational
direction about an axis of rotation to displace the first threaded
collar in a first axial direction and displace the second threaded
collar in a second axial direction, and displacing the superior
component in a first radial direction orthogonal to the first axial
direction, and displace the inferior component in a second radial
direction orthogonal to the first axial direction and opposite the
first radial direction.
16. An expandable interbody spinal fusion device of claim 15
wherein the threaded rod has a first end and a second end, the
first end threaded in a first rotational direction and the second
end of the threaded rod is threaded in a second rotational
direction.
17. The expandable interbody spinal fusion device of claim 15
wherein the first arm further comprises a first recess operatively
arranged to receive the first strut when the expandable interbody
spinal fusion device is in a collapsed state, and the second arm
further comprises a second recess operatively arranged to receive
the second strut when the expandable interbody spinal fusion device
is in a collapsed state.
18. The expandable interbody spinal fusion device of claim 17
wherein the third arm further comprises a third recess operatively
arranged to receive the third strut when the expandable interbody
spinal fusion device is in a collapsed state, and the fourth arm
further comprises a fourth recess operatively arranged to receive
the fourth strut when the expandable interbody spinal fusion device
is in a collapsed state.
19. The expandable interbody spinal fusion device of claim 15
wherein a locking mechanism is positioned on the threaded rod
adjacent to the fixed collar in the first axial direction and the
second axial direction such that the fixed collar is prevented from
being displaced in the first axial direction and the second axial
direction.
20. The expandable interbody spinal fusion device of claim 19
wherein the locking mechanism is a lock washer, crimp ring
retainer, or a serrated lock washer.
Description
FIELD
[0001] The disclosure relates to spinal surgery, more particularly
to intervertebral prosthesis, and, even more specifically, to a
minimally invasive expandable interbody spinal fusion device
capable of being deployed endoscopically.
BACKGROUND
[0002] The spinal column, or backbone, is one of the most important
parts of the body. It provides the main support, allowing us to
stand upright, bend, and twist. As shown in FIG. 1, thirty three
(33) individual bones interlock with each other to form the spinal
column. The vertebrae are numbered and divided into regions. The
cervical vertebrae (C1-C7) form the neck, support the head and
neck, and allow nodding and shaking of the head. The thoracic
vertebrae (T1-T12) join with the ribs to form the rib cage. The
five lumbar vertebrae (L1-L5) carry most of the weight of the upper
body and provide a stable center of gravity when a person moves.
Five vertebrae of the sacrum S and four of the coccyx C are fused.
This comprises the back wall of the pelvis. Intervertebral discs
are located between each of the mobile vertebra. Intervertebral
discs comprise a thick outer layer with a crisscrossing fibrous
structure annulus A that surrounds a soft gel-like center, the
nucleus N. Discs function like shock-absorbing springs. The annulus
pulls the vertebral bodies together against the elastic resistance
of the gel-filled nucleus. When we bend, the nucleus acts like a
ball bearing, allowing the vertebral bodies to roll over the
incompressible gel. Each disc works in concert with two facet
joints, forming a spinal motion segment. The biomechanical function
of each pair of facet joints is to guide and limit the movement of
the spinal motion segment. The surfaces of the joint are coated
with cartilage that helps each joint move smoothly. Directly behind
the discs, the ring-like vertebral bodies create a vertical tunnel
called the spinal canal, or neuro canal. The spinal cord and spinal
nerves pass through the spinal canal, which protects them from
injury. The spinal cord is the major column of nerve tissue that is
connected to the brain and serves as an information super-highway
between the brain and the body. The nerves in the spinal cord
branch off to form pairs of nerve roots that travel through the
small openings between the vertebrae and the intervertebral
foramens.
[0003] The repetitive forces which act on these intervertebral
discs during repetitive day-to-day activities of bending, lifting
and twisting cause them to break down or degenerate over time.
Overt trauma, or covert trauma occurring in the course of
repetitive activities disproportionately affect the more highly
mobile areas of the spine. Disruption of a disc's internal
architecture leads to bulging, herniation or protrusion of pieces
of the disc and eventual disc space collapse. Resulting mechanical
and chemical irritation of surrounding neural elements cause pain,
attended by varying degrees of disability. In addition, loss of
disc space height relaxes tension on the longitudinal ligaments,
thereby contributing to varying degrees of spinal instability such
as spinal curvature.
[0004] Neural irritation and instability resulting from severe disc
damage has been treated by removing the damaged disc and fusing
adjacent vertebral elements. Removal of the disc relieves the
mechanical and chemical irritation of neural elements, while
osseous union solves the problem of instability. For example, in
one surgical procedure, known as a discectomy (or diskectomy) with
interbody fusion, the surgeon removes the nucleus of the disk and
replaces it with an implant. As shown in FIG. 2, it may be
necessary, for example, for the surgeon to remove the nucleus of
the disc between the L3 and L4 vertebrae. Disc D.sub.L3-L4 is shown
in an enlarged view in FIG. 3. This figure also shows various
anatomical structures of the spine, including facets F3A and F4A,
facet joint FJ, spinous processes SP3 and SP4, transverse processes
TP3A and TP4A, and intervertebral foramen IF. FIG. 4 is a top view
of the section of the spinal column shown in FIG. 3, with the L3
vertebra removed to expose annulus A and nucleus N of disc
D.sub.L3-L4. Neural canal NC is also shown. FIG. 5 is an anterior
perspective view of the section of the spinal column shown in FIG.
4. FIG. 6 is a partial cross-sectional view of the section of the
spinal column shown in FIG. 5, but with vertebra L3 in place atop
disc D.sub.L3-L4.
[0005] While cancellous bone appears ideal to provide the biologic
components necessary for osseous union to occur, it does not
initially have the strength to resist the tremendous forces that
may occur in the intervertebral disc space, nor does it have the
capacity to adequately stabilize the spine until long term bony
union occurs. For these reasons, many spinal surgeons have found
that interbody fusion using bone alone has an unacceptably high
rate of bone graft migration or even expulsion or nonunion due to
structural failure of the bone or residual degrees of motion that
retard or prohibit bony union.
[0006] Intervertebral prosthesis in various forms have therefore
been used to provide immediate stability and to protect and
preserve an environment that fosters growth of grafted bone such
that a structurally significant bony fusion can occur.
[0007] Limitations of most present-day intervertebral implants are
significant and revolve largely around marked variation in the disc
space height and shape that results from either biologic
variability or pathologic change. For example, if a disc space is
20 mm in height, a circular implant bridging this gap requires a
minimum diameter of 20 mm just to contact the endplate of the
vertebral bone. Generally, end plate disruption must occur to allow
a generous bony union, meaning that an additional 2-3 mm must be
added on either side resulting in a final implant size of 24-26 mm.
During implantation from an anterior approach (from the front of
the body), excessive retraction (pulling) is often required on the
great blood vessels which greatly enhances the risk of devastating
complication such as vascular tears or thrombosis. On the other
hand, during a posterior approach, large implant diameters may
require excessive traction on neural elements for adequate
placement, even if all posterior bony elements are removed. In some
instances, and adequate implant size cannot be inserted
posteriorly, particularly if there is a significant degree of
distraction to obtain stability by tautening the annular
ligamentous tension band. Compromising implant size risks
sub-optimal stability or a loose implant, both of which create a
greater risk of migration within, or expulsion from, the disc
space.
[0008] While expandable interbody fusion devices are being
increasingly employed in interbody fusion, because of the desire to
use minimally invasive fusion techniques, few have reached the
capacity or capability of being deployed down the working channel
of an endoscope or endoscopic access tube and therefore have not
adequately achieved the ability to participate in true minimally
invasive surgery.
[0009] Thus, there is a long-felt need for a minimally invasive
expandable interbody spinal fusion device capable of easily being
deployed endoscopically.
SUMMARY
[0010] According to aspects illustrated herein, there is provided
an expandable interbody spinal fusion device, including a superior
component an inferior component and an expansion mechanism. The
expansion mechanism includes a threaded rod, a threaded collar
operatively arranged to engage with the threaded rod and axially
translate in a first axial direction, a fixed collar secured about
the threaded rod, a first arm pivotably secured to the fixed
collar, and a first strut pivotably secured to the first arm and
the threaded collar.
[0011] According to aspects illustrated herein, there is provided
an expandable interbody spinal fusion device, including a superior
component, an inferior component and a first expansion mechanism.
The first expansion mechanism includes a threaded rod, a superior
plate, an inferior plate, a first threaded collar operatively
arranged to engage with the threaded rod, a first fixed collar
fixedly arranged about the threaded rod, a first arm pivotably
secured to the superior plate and the first fixed collar, a first
strut pivotably secured to the first arm and the first threaded
collar, a second arm pivotably secured to the inferior plate the
first fixed collar, and a second strut pivotably secured to the
second arm and the first threaded collar, wherein the threaded rod
is rotated about a first axis of rotation in a first rotational
direction to displace the superior component in a first direction
orthogonal to the first axis of rotation.
[0012] According to aspects illustrated herein, there is provided
an expandable interbody spinal fusion device, including a superior
component, an inferior component, and an expansion mechanism. The
expansion mechanism includes a superior plate, an inferior plate, a
threaded rod a first threaded collar operatively arranged to engage
with the threaded rod, a second threaded collar operatively
arranged to engage with the threaded rod, a fixed collar arranged
about the threaded rod, a first arm pivotably secured to the
superior plate and the fixed collar, a first strut pivotably
secured to the first arm and the first threaded collar, a second
arm pivotably secured to the inferior plate and the fixed collar, a
second strut pivotably secured to the second arm and the first
threaded collar, a third arm pivotably secured to the superior
plate and the fixed collar, a third strut pivotably secured to the
third arm and the second threaded collar, a fourth arm pivotably
secured to the inferior plate and the fixed collar, and a fourth
strut pivotably secured to the fourth arm and the second threaded
collar, wherein the threaded rod is rotated in a first rotational
direction about an axis of rotation to displace the first threaded
collar in a first axial direction and displace the second threaded
collar in a second axial direction, and displacing the superior
component in a first radial direction orthogonal to the first axial
direction, and displace the inferior component in a second radial
direction orthogonal to the first axial direction and opposite the
first radial direction.
[0013] These, and other objects and advantages, will be readily
appreciable from the following description of preferred embodiments
and from the accompanying drawings and claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] The nature and mode of operation of the present disclosure
will now be more fully described in the following detailed
description of the embodiments taken with the accompanying figures,
in which:
[0015] FIG. 1 is an anterior perspective view of spinal column
10;
[0016] FIG. 2 is an anterior perspective view of the lumbar section
of spinal column 10;
[0017] FIG. 3 is a lateral perspective view of L3, L4 vertebrae and
disc D.sub.L3-L4 and related spinal anatomy;
[0018] FIG. 4 is a top view of a section of the spinal column,
taken generally along line 4-4 in FIG. 3;
[0019] FIG. 5 is an enlarged anterior perspective view of the
spinal column shown in FIG. 2, except with vertebra L3 and all
other structure above L3 removed;
[0020] FIG. 6 is a partial cross-sectional view of the L4 vertebra
and D.sub.L3-L4 disc shown in FIG. 5, including L3 in
cross-section;
[0021] FIG. 7 is a partial cross-sectional view of the L4 vertebra
and D.sub.L3-L4 disc shown in FIG. 5, showing the removal of the
disc nucleus post-discectomy;
[0022] FIG. 8 illustrates the introduction of an expandable
interbody spinal fusion device into the disc space in an unexpanded
state;
[0023] FIG. 9 is a perspective view of an expandable interbody
spinal fusion device with a first example embodiment of expansion
mechanisms in position therein, in a collapsed state;
[0024] FIG. 10 is a perspective view of an expandable interbody
spinal fusion device with a first example embodiment of expansion
mechanisms in position therein, in an expanded state;
[0025] FIG. 11 is a front elevational view of an expandable
interbody spinal fusion device with a first example embodiment of
expansion mechanisms in position therein, in a collapsed state;
[0026] FIG. 12 is a cross-sectional view of an expandable interbody
spinal fusion device taken generally along line 12-12 in FIG. 11
with a first example embodiment of expansion mechanisms in position
therein, in a collapsed state;
[0027] FIG. 13 is a front elevational view of an expandable
interbody spinal fusion device with a first example embodiment of
expansion mechanisms in position therein, in an expanded state;
[0028] FIG. 14 is a cross-sectional view of an expandable interbody
spinal fusion device taken generally along line 14-14 in FIG. 13
with a first example embodiment of expansion mechanisms in position
therein, in an expanded state;
[0029] FIG. 15 is a perspective view of a first example embodiment
of an expansion mechanism in a collapsed state;
[0030] FIG. 16 is a perspective view of a first example embodiment
of an expansion mechanism in an expanded state;
[0031] FIG. 17 is a perspective view of a second example embodiment
of an expansion mechanism in a collapsed state;
[0032] FIG. 18 is a perspective view of a second example embodiment
of an expansion mechanism in an expanded state;
[0033] FIG. 19 is a perspective view of a third example embodiment
of an expansion mechanism in a collapsed state;
[0034] FIG. 20 is a perspective view of a third example embodiment
of an expansion mechanism in an expanded state.
DETAILED DESCRIPTION OF EMBODIMENTS
[0035] At the outset, it should be appreciated that like drawing
numbers on different drawing views identify identical, or
functionally similar, structural elements. While the embodiments
are described with respect to what is presently considered to be
the preferred aspects, it is to be understood that the invention as
claimed is not limited to the disclosed aspect. The present
invention is intended to include various modifications and
equivalent arrangements within the spirit and scope of the appended
claims.
[0036] The term "Superior Component" as used in the present
disclosure is intended to mean the component of the body of the
implant located in the highest position relative to the other
components in first radial direction RD1.
[0037] The term "Inferior Component" as used in the present
disclosure is intended to mean the component of the body of the
implant located in the lowest position relative to the other
components in first radial direction RD1.
[0038] Moreover, as used herein, "and/or" is intended to mean a
grammatical conjunction used to indicate that one or more of the
elements or conditions recited may be included or occur. For
example, a device comprising a first element, a second element
and/or a third element, is intended to be construed as any one of
the following structural arrangements: a device comprising a first
element; a device comprising a second element; a device comprising
a third element; a device comprising a first element and a second
element; a device comprising a first element and a third element; a
device comprising a first element, a second element and a third
element; or, a device comprising a second element and a third
element.
[0039] Furthermore, it is understood that this disclosure is not
limited to the particular methodology, materials and modifications
described and, as such, may, of course, vary. It is also understood
that the terminology used herein is for the purpose of describing
particular aspects only, and is not intended to limit the scope of
the present invention, which is limited only by the appended
claims.
[0040] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood to one of
ordinary skill in the art to which this invention belongs. Although
any methods, devices or materials similar or equivalent to those
described herein can be used in the practice or testing of the
invention, the preferred methods, devices, and materials are now
described.
[0041] Adverting now to the Figures, and as described previously,
FIGS. 1-6 depict various parts and sections of spinal anatomy. FIG.
7 illustrates a partial cross-sectional view of the L3 and L4
vertebra with disc D.sub.L3-L4 removed (post discectomy) able to
receive expandable interbody spinal fusion device 100.
[0042] FIG. 8 illustrates a partial cross-sectional view of the L3
and L4 vertebra with expandable interbody spinal fusion device 100
in place within disc space 12 in an unexpanded state.
[0043] FIG. 9 is a perspective view of expandable interbody spinal
fusion device 100 with expansion mechanisms 106 (discussed infra)
in position therein, in a collapsed state. Device 100 comprises
superior component 102, inferior component 104, and expansion
mechanisms 106 arranged to displace superior component 102 in a
first radial direction RD1 relative to inferior component 104
giving device 100 an expanded height H.sub.2 (shown in FIG. 10)
greater than unexpanded height H.sub.1. Superior component 102 and
inferior component 104 further comprise at least one first aperture
108 arranged to allow fusion between bone fusing material and the
adjacent vertebra, and a second aperture 110 is located on the
front face of device 100 and arranged to allow the introduction of
bone fusing material into device 100 during surgery. Second
aperture 110 is illustrated as an arched slot as a non-limiting
example, however, it should be appreciated that second aperture 110
could be any suitable aperture that would allow for the
introduction of bone fusing material into device 100.
[0044] FIG. 10 is a perspective view of expandable interbody spinal
fusion device 100 with expansion mechanisms 106 in position
therein, in an expanded state. During surgery and after device 100
is implanted in disc space 12, a surgeon can apply torque to
expansion mechanisms 106 via any device that imparts rotational
force upon expansion mechanisms 106 (e.g., a screw driver or impact
driver). Although not illustrated, various means to engage a screw
driver or impact driver can be affixed to either end of rod 116
(discussed infra) of expansion mechanisms 106, e.g., the rod could
have an embedded cavity having the shape of various screw heads
known in the art, or an additional physical member having any of
the various screw heads known in the art could be affixed to rod
116. This rotational force causes expansion mechanisms 106 to
displace superior component 102 in radial direction RD1 relative to
inferior component 104 giving device 100 an expanded height
H.sub.2, greater than H.sub.1. It should be appreciated that
expansion mechanisms 106 can be expanded to any height between
unexpanded height H.sub.1 and expanded height H.sub.2. Although
device 100 is illustrated with expansion mechanisms 106 disposed
therein, it should be appreciated that device 100 can also include
other expansion mechanisms e.g., expansion mechanisms 206 and 306
discussed infra, and any combination of these expansion mechanisms
therein.
[0045] FIG. 11 is a front elevational view of expandable interbody
spinal fusion device 100 with expansion mechanisms 106 in position
therein, in a collapsed state. FIG. 12 is a cross-sectional view of
expandable interbody spinal fusion device 100, taken generally
along line 12-12 in FIG. 11 with expansion mechanisms 106 in
position therein, in a collapsed state.
[0046] FIG. 13 is a front elevational view of expandable interbody
spinal fusion device 100 with expansion mechanisms 106 in position
therein, in an expanded state. FIG. 14 is a cross-sectional view of
expandable interbody spinal fusion device 100 taken generally along
line 14-14 in FIG. 13 with expansion mechanisms 106 in position
therein, in an expanded state.
[0047] FIGS. 15 and 16 illustrate perspective views of expansion
mechanism 106 in a collapsed and expanded state, respectively.
Expansion mechanism 106 includes superior plate 112, inferior plate
114, threaded rod 116 having first end 118 and second end 120,
first threaded collar 122, first fixed collar 124, first arm 126,
first strut 128, second arm 130, second strut 132, and locking
mechanism 134. Superior plate 112 and inferior plate 114 are
substantially planar members spanning a substantial portion of the
length of device 100 when in place therein. Superior plate 112 and
inferior plate 114 are arranged to contact and engage with the
inner surface of superior component 102 and inferior component 104
of device 100, respectively. Threaded rod 116 is arranged to run
along the length of device 100 and to rotate within device 100 in
either first rotational direction RO1 or second rotational
direction RO2. Threaded rod 116 has an outer circumferential
surface which contains helical threading. The helical threading can
be threaded in first rotational direction RO1 and/or second
rotational direction RO2.
[0048] First threaded collar 122 is a substantially toroidal member
with inner threading operatively arranged to receive and engage
with the helical threading on first end 118 of threaded rod 116. As
threaded rod 116 is rotated in first rotational direction RO1 or
second rotational direction RO2, the first threaded collar 122
translates about threaded rod 116 in first axial direction AD1 or
second axial direction AD2, dependent on the direction of rotation
of threaded rod 116. First fixed collar 124 is a substantially
toroidal member arranged about threaded rod 116 and arranged to
rotate freely in place and maintain position in first axial
direction AD1. This free rotation can be accomplished by leaving
the inner circumferential surface of first fixed collar 124 free of
threading, such that the threading of threaded rod 116 cannot
engage with and influence first fixed collar 124. Additionally, a
locking mechanism, i.e., locking mechanism 134, discussed infra,
can be used to prevent first fixed collar 124 from translating
about threaded rod 116 in first axial direction AD1 and/or second
axial direction AD2. Alternatively, and although not illustrated in
the figures, the inner circumferential surface of first fixed
collar 124 can contain an annular protrusion arranged to fit
within, and slidingly engage with, a corresponding annular recess
at a fixed axial position on the outer circumferential surface of
threaded rod 116.
[0049] First arm 126 is pivotably connected between first fixed
collar 124 and superior plate 112. One end of first arm 126 is
pivotably connected to a protrusion on the inner surface of
superior plate 112 which can comprise a pin arranged to allow first
arm 126 to pivot with respect to superior plate 112. The other end
of first arm 126 is pivotably connected to a protrusion on the
outer circumferential surface of first fixed collar 124 which can
comprise a pin arranged to allow first arm 126 to pivot with
respect to first fixed collar 124. First strut 128 is pivotably
connected between first threaded collar 122 and first arm 126. One
end of first strut 128 is pivotably connected to a protrusion on
the outer circumferential surface of first threaded collar 122
which can comprise a pin arranged to allow first strut 128 to pivot
with respect to first threaded collar 122. The other end of first
strut 128 is pivotably connected to first arm 126 which can
comprise a pin arranged to allow first strut 128 to pivot with
respect to first arm 126.
[0050] Second arm 130 is pivotably connected between first fixed
collar 124 and inferior plate 114. One end of second arm 130 is
pivotably connected to a protrusion on the inner surface of
inferior plate 114 which can comprise a pin arranged to allow
second arm 130 to pivot with respect to inferior plate 114. The
other end of second arm 130 is pivotably connected to a second
protrusion on the outer circumferential surface of first fixed
collar 124 which can comprise a pin arranged to allow second arm
130 to pivot with respect to first fixed collar 124. Second strut
132 is pivotably connected between first threaded collar 122 and
second arm 130. One end of second strut 132 is pivotably connected
to a second protrusion on the outer circumferential surface of
first threaded collar 122 which can comprise a pin arranged to
allow second strut 132 to pivot with respect to first threaded
collar 122. The other end of second strut 132 is pivotably
connected to second arm 130 which can comprise a pin arranged to
allow second strut 132 to pivot with respect to second arm 130.
[0051] Locking mechanism 134 is arranged about threaded rod 116 and
can be positioned axially adjacent to first fixed collar 124 in the
first axial direction AD1 and/or the second axial direction AD2. As
first fixed collar 124 does not have internal threading, locking
mechanism 134 prevents first fixed collar 124 from translating
about threaded rod 116 in first axial direction AD1 and/or second
axial direction AD2. In an example embodiment, locking mechanism
134 is a lock washer, a crimp ring retainer, or a serrated lock
washer. However, it should be appreciated that locking mechanism
134 can be any mechanism suitable for preventing axial translation
of fixed collar 124 about a rod.
[0052] During surgery, and after device 100 containing expansion
mechanisms 106 is implanted in situ within disc space 12, a surgeon
can apply torque to threaded rod 116 via any device that imparts
rotational force (e.g., a screw driver or impact driver). As
threaded rod 116 rotates in first rotational direction RO1, first
fixed collar 124 maintains a fixed axial position about threaded
rod 116 as it is confined by locking mechanism 134. Additionally,
as threaded rod 116 rotates in first rotational direction RO1, the
inner circumferential threading of first threaded collar 122
engages with the helical threading of threaded rod 116 causing
first threaded collar 122 to translate in first axial direction
AD1. The translational motion imparted to first threaded collar
122, in conjunction with the lack of translational motion of first
fixed collar 124, imparts a force upon first strut 128 and second
strut 132 which in turn impart a force upon first arm 126 and
second arm 130 in first radial direction RD1 and second radial
direction RD2, respectively.
[0053] Expansion mechanism 106 also includes second threaded collar
136, second fixed collar 138, third arm 140, third strut 142,
fourth arm 144, fourth strut 146, and locking mechanism 148. Second
threaded collar 136 is a substantially toroidal member with inner
threading operatively arranged to receive and engage with the
helical threading on second end 120 of threaded rod 116. As
threaded rod 116 is rotated in first rotational direction RO1 or
second rotational direction RO2, second threaded collar 136
translates about threaded rod 116 in first axial direction AD1 or
second axial direction AD2, dependent on the direction of rotation
of threaded rod 116. Second fixed collar 138 is a substantially
toroidal member arranged about threaded rod 116 and arranged to
rotate freely in place and maintain position in first axial
direction AD1. This free rotation can be accomplished by leaving
the inner circumferential surface of second fixed collar 138 free
of threading, such that the threading of threaded rod 116 cannot
engage with and influence second fixed collar 138. Additionally, a
locking mechanism, i.e., locking mechanism 148, discussed infra,
can be used to prevent second fixed collar 138 from translating
about threaded rod 116 in first axial direction AD1 and/or second
axial direction AD2. Alternatively, and although not illustrated in
the figures, the inner circumferential surface of second fixed
collar 138 can contain an annular protrusion arranged to fit within
and slidingly engage with a corresponding annular recess at a fixed
axial position on the outer circumferential surface of threaded rod
116.
[0054] Third arm 140 is pivotably connected between second fixed
collar 138 and superior plate 112. One end of third arm 140 is
pivotably connected to a protrusion on the inner surface of
superior plate 112 which can comprise a pin arranged to allow third
arm 140 to pivot with respect to superior plate 112. The other end
of third arm 140 is pivotably connected to a protrusion on the
outer circumferential surface of second fixed collar 138 which can
comprise a pin arranged to allow third arm 140 to pivot with
respect to second fixed collar 138. Third strut 142 is pivotably
connected between second threaded collar 136 and third arm 140. One
end of third strut 142 is pivotably connected to a protrusion on
the outer circumferential surface of second threaded collar 136
which can comprise a pin arranged to allow third strut 142 to pivot
with respect to second threaded collar 136. The other end of third
strut 142 is pivotably connected to third arm 140 which can
comprise a pin arranged to allow third strut 142 to pivot with
respect to third arm 140.
[0055] Fourth arm 144 is pivotably connected between second fixed
collar 138 and inferior plate 114. One end of fourth arm 144 is
pivotably connected to a protrusion on the inner surface of
inferior plate 114 which can comprise a pin arranged to allow
fourth arm 144 to pivot with respect to inferior plate 114. The
other end of fourth arm 144 is pivotably connected to a second
protrusion on the outer circumferential surface of second fixed
collar 138 which can comprise a pin arranged to allow fourth arm
144 to pivot with respect to second fixed collar 138. Fourth strut
146 is pivotably connected between second threaded collar 136 and
fourth arm 144. One end of fourth strut 146 is pivotably connected
to a second protrusion on the outer circumferential surface of
second threaded collar 136 which can comprise a pin arranged to
allow fourth strut 146 to pivot with respect to second threaded
collar 136. The other end of fourth strut 146 is pivotably
connected to fourth arm 144 which can comprise a pin arranged to
allow fourth strut 146 to pivot with respect to fourth arm 144.
[0056] A second locking mechanism, i.e., locking mechanism 148 can
be arranged about threaded rod 116 and be positioned axially
adjacent to second fixed collar 138 in the first axial direction
AD1 and/or the second axial direction AD2. As second fixed collar
138 does not have internal threading, locking mechanism 148
prevents second fixed collar 138 from translating about threaded
rod 116 in first axial direction AD1 and/or second axial direction
AD2. In an example embodiment, locking mechanism 148 is a lock
washer, a crimp ring retainer, or a serrated lock washer. However,
it should be appreciated that locking mechanism 148 can be any
mechanism suitable for preventing axial translation about a rod. It
should be appreciated that the opposing movement of first threaded
collar 122 and second threaded collar 136 can be achieved by having
opposing threading on their respective inner circumferential
surfaces (as can be seen in FIGS. 12 and 14), or the threaded
collars could have identical threading and first end 118 of
threaded rod 116 could comprise helical threading of a first
direction while second end 120 of threaded rod 116 could comprise
helical threading of a second direction opposite the first
direction.
[0057] During surgery, and after device 100 containing expansion
mechanisms 106 is implanted in situ within disc space 12, a surgeon
can apply torque to threaded rod 116 via any device that imparts
rotational force (e.g., a screw driver or impact driver). As
threaded rod 116 rotates in first rotational direction RO1, second
fixed collar 138 maintains a fixed axial position about threaded
rod 116 as it is confined by locking mechanism 148. Additionally,
as threaded rod 116 rotates in first rotational direction RO1, the
inner circumferential threading of second threaded collar 136
engages with the helical threading of threaded rod 116 causing
second threaded collar 136 to translate in second axial direction
AD2. The translational motion imparted to second threaded collar
136, in conjunction with the lack of translational motion of second
fixed collar 138, imparts a force upon third strut 142 and fourth
strut 146 which in turn impart a force upon third arm 140 and
fourth arm 144 in first radial direction RD1 and second radial
direction RD2, respectively.
[0058] First arm 126, second arm 130, third arm 140, and fourth arm
144, contain a recess, i.e., first recess 150, second recess 152,
third recess 154, and fourth recess 156, respectively. When
expansion mechanism 106 is in a collapsed state as illustrated in
FIG. 15, first recess 150 of first arm 126 is arranged to receive
first strut 128 such that first strut 128 is completely nested
within first recess 150. Similarly, second recess 152, third recess
154, and fourth recess 156 are arranged to receive second strut
132, third strut 142, and fourth strut 146, respectively, such that
each strut is completely nested within a respective recess.
Alternatively, each strut could contain a recess arranged to
receive each arm such that each arm is nested completely within the
recess of each respective strut.
[0059] FIGS. 17 and 18 illustrate perspective views of expansion
mechanism 206 in a collapsed and expanded state, respectively.
Expansion mechanism 206 includes superior plate 212, inferior plate
214, threaded rod 216 having first end 218 and second end 220,
first threaded collar 222, fixed collar 224, first arm 226, first
strut 228, second arm 230, second strut 232, and locking mechanism
234 (not shown). Superior plate 212 and inferior plate 214 are
substantially planar members spanning a substantial portion of the
length of a device when in place therein, e.g., device 100.
Superior plate 212 and inferior plate 214 are arranged to contact
and engage with the inner surface of superior component 102 and
inferior component 104 of device 100, respectively. Threaded rod
216 is arranged to run along the length of device 100 and to rotate
within device 100 in either first rotational direction RO1 or
second rotational direction RO2. Threaded rod 216 has an outer
circumferential surface which contains helical threading. The
helical threading can be threaded in first rotational direction RO1
and/or second rotational direction RO2.
[0060] First threaded collar 222 is a substantially toroidal member
with inner threading operatively arranged to receive and engage
with the helical threading on first end 218 of threaded rod 216. As
threaded rod 216 is rotated in first rotational direction RO1 or
second rotational direction RO2, the first threaded collar 222
translates about threaded rod 216 in first axial direction AD1 or
second axial direction AD2, dependent on the direction of rotation
of threaded rod 216. Fixed collar 224 is a substantially toroidal
member arranged about threaded rod 216 and arranged to rotate
freely in place and maintain position in first axial direction AD1.
This free rotation can be accomplished by leaving the inner
circumferential surface of fixed collar 224 free of threading, such
that the threading of threaded rod 216 cannot engage with and
influence fixed collar 224. Additionally, a locking mechanism,
i.e., locking mechanism 234 (not shown), discussed infra, can be
used to prevent fixed collar 224 from translating about threaded
rod 216 in first axial direction AD1 and/or second axial direction
AD2. Alternatively, and although not illustrated in the figures,
the inner circumferential surface of fixed collar 224 can contain
an annular protrusion arranged to fit within and slidingly engage
with a corresponding annular recess at a fixed axial position on
the outer circumferential surface of threaded rod 216.
[0061] First arm 226 is pivotably connected between fixed collar
224 and superior plate 212. One end of first arm 226 is pivotably
connected to a protrusion on the inner surface of superior plate
212 which can comprise a pin arranged to allow first arm 226 to
pivot with respect to superior plate 212. The other end of first
arm 226 is pivotably connected to a first protrusion on the outer
circumferential surface of fixed collar 224 which can comprise a
pin arranged to allow first arm 226 to pivot with respect to fixed
collar 224. First strut 228 is pivotably connected between first
threaded collar 222 and first arm 226. One end of first strut 228
is pivotably connected to a protrusion on the outer circumferential
surface of first threaded collar 222 which can comprise a pin
arranged to allow first strut 228 to pivot with respect to first
threaded collar 222. The other end of first strut 228 is pivotably
connected to first arm 226 which can comprise a pin arranged to
allow first strut 228 to pivot with respect to first arm 226.
[0062] Second arm 230 is pivotably connected between fixed collar
224 and inferior plate 214. One end of second arm 230 is pivotably
connected to a protrusion on the inner surface of inferior plate
214 which can comprise a pin arranged to allow second arm 230 to
pivot with respect to inferior plate 214. The other end of second
arm 230 is pivotably connected to a second protrusion on the outer
circumferential surface of fixed collar 224 which can comprise a
pin arranged to allow second arm 230 to pivot with respect to fixed
collar 224. Second strut 232 is pivotably connected between first
threaded collar 222 and second arm 230. One end of second strut 232
is pivotably connected to a second protrusion on the outer
circumferential surface of first threaded collar 222 which can
comprise a pin arranged to allow second strut 232 to pivot with
respect to first threaded collar 222. The other end of second strut
232 is pivotably connected to second arm 230 which can comprise a
pin arranged to allow second strut 232 to pivot with respect to
second arm 230.
[0063] Expansion mechanism 206 also includes second threaded collar
236, third arm 240, third strut 242, fourth arm 244, and fourth
strut 246. Second threaded collar 236 is a substantially toroidal
member with inner threading operatively arranged to receive and
engage with the helical threading on second end 220 of threaded rod
216. As threaded rod 216 is rotated in first rotational direction
RO1 or second rotational direction RO2, second threaded collar 236
translates about threaded rod 216 in first axial direction AD1 or
second axial direction AD2 dependent on the direction of rotation
of threaded rod 216.
[0064] Third arm 240 is pivotably connected between fixed collar
224 and superior plate 212. One end of third arm 240 is pivotably
connected to a protrusion on the inner surface of superior plate
212 which can comprise a pin arranged to allow third arm 240 to
pivot with respect to superior plate 212. The other end of third
arm 240 is pivotably connected to a third protrusion on the outer
circumferential surface of fixed collar 224 which can comprise a
pin arranged to allow third arm 240 to pivot with respect to fixed
collar 224. Third strut 242 is pivotably connected between second
threaded collar 236 and third arm 240. One end of third strut 242
is pivotably connected to a protrusion on the outer circumferential
surface of second threaded collar 236 which can comprise a pin
arranged to allow third strut 242 to pivot with respect to second
threaded collar 236. The other end of third strut 242 is pivotably
connected to third arm 240 which can comprise a pin arranged to
allow third strut 242 to pivot with respect to third arm 240.
[0065] Fourth arm 244 is pivotably connected between fixed collar
224 and inferior plate 214. One end of fourth arm 244 is pivotably
connected to a protrusion on the inner surface of inferior plate
214 which can comprise a pin arranged to allow fourth arm 244 to
pivot with respect to inferior plate 214. The other end of fourth
arm 244 is pivotably connected to a fourth protrusion on the outer
circumferential surface of fixed collar 224 which can comprise a
pin arranged to allow fourth arm 244 to pivot with respect to fixed
collar 224. Fourth strut 246 is pivotably connected between second
threaded collar 236 and fourth arm 244. One end of fourth strut 246
is pivotably connected to a second protrusion on the outer
circumferential surface of second threaded collar 236 which can
comprise a pin arranged to allow fourth strut 246 to pivot with
respect to second threaded collar 236. The other end of fourth
strut 246 is pivotably connected to fourth arm 244 which can
comprise a pin arranged to allow fourth strut 246 to pivot with
respect to fourth arm 244.
[0066] Locking mechanism 234 (not shown) can be arranged about
threaded rod 216 and be positioned axially adjacent to fixed collar
224 in the first axial direction AD1 and/or the second axial
direction AD2. As fixed collar 224 does not have internal
threading, locking mechanism 234 prevents fixed collar 224 from
translating about threaded rod 216 in first axial direction AD1
and/or second axial direction AD2. In an example embodiment,
locking mechanism 234 is a lock washer, a crimp ring retainer, or a
serrated lock washer. However, it should be appreciated that
locking mechanism 234 can be any mechanism suitable for preventing
axial translation about a cylindrical rod.
[0067] During surgery, and after device 100 containing expansion
mechanisms 206 is implanted in situ within disc space 12, a surgeon
can apply torque to threaded rod 216 via any device that imparts
rotational force (e.g., a screw driver or impact driver). As
threaded rod 216 rotates in first rotational direction RO1, fixed
collar 224 maintains a fixed axial position about threaded rod 216
as it is confined by locking mechanism(s) 234. Additionally, as
threaded rod 216 rotates in first rotational direction RO1, the
inner circumferential threading of first threaded collar 222 and
second threaded collar 236 engages with the helical threading of
threaded rod 216 causing first threaded collar 222 and second
threaded collar 236 to translate in first axial direction AD1 and
second axial direction AD2, respectively. The translational motion
imparted to first threaded collar 222 and second threaded collar
236, in conjunction with the lack of translational motion of fixed
collar 224, imparts a force upon first strut 228, second strut 232,
third strut 242, and fourth strut 246, which in turn impart a force
upon first arm 226, second arm 230, third arm 240, and fourth arm
244, displacing superior plate 212 and inferior plate 214 in first
radial direction RD1 and second radial direction RD2,
respectively.
[0068] Although not illustrated, first arm 226, second arm 230,
third arm 240, and fourth arm 244, contain a recess, i.e., first
recess 250, second recess 252, third recess 254, and fourth recess
256, respectively. When expansion mechanism 206 is in a collapsed
state as illustrated in FIG. 17, first recess 250 of first arm 226
is arranged to receive first strut 228 such that first strut 228 is
completely nested within first recess 250. Similarly, second recess
252, third recess 254, and fourth recess 256 are arranged to
receive second strut 232, third strut 242, and fourth strut 246,
respectively, such that each strut is completely nested within a
respective recess. Alternatively, each strut could contain a recess
arranged to receive each arm such that each arm is nested
completely within the recess of each respective strut.
[0069] FIGS. 19 and 20 illustrate perspective views of expansion
mechanism 306 in a collapsed and an expanded state, respectively.
Expansion mechanism 306 includes superior plate 312, inferior plate
314, threaded rod 316 having first end 318 and second end 320,
first threaded collar 322, first fixed collar 324, first arm 326,
first strut 328, second arm 330, second strut 332, fifth arm 358,
fifth strut 360, sixth arm 362, sixth strut 364, and locking
mechanism 33 (not shown). Superior plate 312 and inferior plate 314
are substantially planar members spanning a substantial portion of
the length of a device, e.g., device 100. Superior plate 312 and
inferior plate 314 are arranged to contact and engage with the
inner surface of superior component 102 and inferior component 104
of device 100, respectively. Threaded rod 316 is arranged to run
along the length of device 100 and to rotate within device 100 in
either first rotational direction RO1 or second rotational
direction RO2. Threaded rod 316 has an outer circumferential
surface which contains helical threading. The helical threading can
be threaded in first rotational direction RO1 and/or second
rotational direction RO2.
[0070] First threaded collar 322 is a substantially toroidal member
with inner threading operatively arranged to receive and engage
with the helical threading on first end 318 of threaded rod 316. As
threaded rod 316 is rotated in first rotational direction RO1 or
second rotational direction RO2, the first threaded collar 322
translates about threaded rod 316 in first axial direction AD1 or
second axial direction AD2, dependent on the direction of rotation
of threaded rod 316. First fixed collar 324 is a substantially
toroidal member arranged about threaded rod 316 and arranged to
rotate freely in place and maintain position in first axial
direction AD1. This free rotation can be accomplished by leaving
the inner circumferential surface of first fixed collar 324 free of
threading, such that the threading of threaded rod 316 cannot
engage with and influence first fixed collar 324. Additionally, a
locking mechanism, i.e., locking mechanism 334 (not shown),
discussed infra, can be used to prevent first fixed collar 324 from
translating about threaded rod 316 in first axial direction AD1
and/or second axial direction AD2. Alternatively, and although not
illustrated in the figures, the inner circumferential surface of
first fixed collar 324 can contain an annular protrusion arranged
to fit within and slidingly engage with a corresponding annular
recess at a fixed axial position on the outer circumferential
surface of threaded rod 316.
[0071] First arm 326 is pivotably connected between first fixed
collar 324 and superior plate 312. One end of first arm 326 is
pivotably connected to a protrusion on the inner surface of
superior plate 312 which can comprise a pin arranged to allow first
arm 326 to pivot with respect to superior plate 312. The other end
of first arm 326 is pivotably connected to a protrusion on the
outer circumferential surface of first fixed collar 324 which can
comprise a pin arranged to allow first arm 326 to pivot with
respect to first fixed collar 324. First strut 328 is pivotably
connected between first threaded collar 322 and first arm 326. One
end of first strut 328 is pivotably connected to a protrusion on
the outer circumferential surface of first threaded collar 322
which can comprise a pin arranged to allow first strut 328 to pivot
with respect to first threaded collar 322. The other end of first
strut 328 is pivotably connected to first arm 326 which can
comprise a pin arranged to allow first strut 328 to pivot with
respect to first arm 326.
[0072] Second arm 330 is pivotably connected between first fixed
collar 324 and inferior plate 314. One end of second arm 330 is
pivotably connected to a protrusion on the inner surface of
inferior plate 314 which can comprise a pin arranged to allow
second arm 330 to pivot with respect to inferior plate 314. The
other end of second arm 330 is pivotably connected to a second
protrusion on the outer circumferential surface of first fixed
collar 324 which can comprise a pin arranged to allow second arm
330 to pivot with respect to first fixed collar 324. Second strut
332 is pivotably connected between first threaded collar 322 and
second arm 330. One end of second strut 332 is pivotably connected
to a second protrusion on the outer circumferential surface of
first threaded collar 322 which can comprise a pin arranged to
allow second strut 332 to pivot with respect to first threaded
collar 322. The other end of second strut 332 is pivotably
connected to second arm 330 which can comprise a pin arranged to
allow second strut 332 to pivot with respect to second arm 330.
[0073] Fifth arm 358 is pivotably connected between first fixed
collar 324 and superior plate 312. One end of fifth arm 358 is
pivotably connected to a protrusion on the inner surface of
superior plate 312 which can comprise a pin arranged to allow fifth
arm 358 to pivot with respect to superior plate 312. The other end
of fifth arm 358 is pivotably connected to a third protrusion on
the outer circumferential surface of first fixed collar 324 which
can comprise a pin arranged to allow fifth arm 358 to pivot with
respect to first fixed collar 324. Fifth strut 360 is pivotably
connected between first threaded collar 322 and fifth arm 358. One
end of fifth strut 360 is pivotably connected to a third protrusion
on the outer circumferential surface of first threaded collar 322
which can comprise a pin arranged to allow fifth strut 360 to pivot
with respect to first threaded collar 322. The other end of fifth
strut 360 is pivotably connected to fifth arm 358 which can
comprise a pin arranged to allow fifth strut 360 to pivot with
respect to fifth arm 358.
[0074] Sixth arm 362 is pivotably connected between first fixed
collar 324 and inferior plate 314. One end of sixth arm 362 is
pivotably connected to a protrusion on the inner surface of
inferior plate 314 which can comprise a pin arranged to allow sixth
arm 362 to pivot with respect to inferior plate 314. The other end
of sixth arm 362 is pivotably connected to a fourth protrusion on
the outer circumferential surface of first fixed collar 324 which
can comprise a pin arranged to allow sixth arm 362 to pivot with
respect to first fixed collar 324. Sixth strut 364 is pivotably
connected between first threaded collar 322 and sixth arm 362. One
end of sixth strut 364 is pivotably connected to a fourth
protrusion on the outer circumferential surface of first threaded
collar 322 which can comprise a pin arranged to allow sixth strut
364 to pivot with respect to first threaded collar 322. The other
end of sixth strut 364 is pivotably connected to sixth arm 362
which can comprise a pin arranged to allow sixth strut 364 to pivot
with respect to sixth arm 362.
[0075] Locking mechanism 334 (not shown) is arranged about threaded
rod 316 and be positioned axially adjacent to first fixed collar
324 in the first axial direction AD1 and/or the second axial
direction AD2. As first fixed collar 324 does not have internal
threading, locking mechanism 334 prevents first fixed collar 324
from translating about threaded rod 316 in first axial direction
AD1 and/or second axial direction AD2. In an example embodiment,
locking mechanism 334 is a lock washer, a crimp ring retainer, or a
serrated lock washer. However, it should be appreciated that
locking mechanism 334 can be any mechanism suitable for preventing
axial translation about a cylindrical rod.
[0076] During surgery, and after device 100 containing expansion
mechanisms 306 is implanted in situ within disc space 12, a surgeon
can apply torque to threaded rod 316 via any device that imparts
rotational force (e.g., a screw driver or impact driver). As
threaded rod 316 rotates in first rotational direction RO1, first
fixed collar 324 maintains a fixed axial position about threaded
rod 316 as it is confined by locking mechanism 334. Additionally,
as threaded rod 316 rotates in first rotational direction RO1, the
inner circumferential threading of first threaded collar 322
engages with the helical threading of threaded rod 316 causing
first threaded collar 322 to translate in first axial direction
AD1. The translational motion imparted to first threaded collar
322, in conjunction with the lack of translational motion of first
fixed collar 324, imparts a force upon first strut 328, second
strut 332, fifth strut 360, and sixth strut 364, which in turn
impart a force upon first arm 326 and fifth arm 358 in first radial
direction RD1, and second arm 330 and sixth arm 362 in second
radial direction RD2.
[0077] Expansion mechanism 306 also includes second threaded collar
336, second fixed collar 338, third arm 340, third strut 342,
fourth arm 344, fourth strut 346, seventh arm 366, seventh strut
368, eight arm 370, eight strut 372, and locking mechanism 348 (not
shown). Second threaded collar 336 is a substantially toroidal
member with inner threading operatively arranged to receive and
engage with the helical threading on second end 320 of threaded rod
316. As threaded rod 316 is rotated in first rotational direction
RO1 or second rotational direction RO2, second threaded collar 336
translates about threaded rod 316 in first axial direction AD1 or
second axial direction AD2, dependent on the direction of rotation
of threaded rod 316. Second fixed collar 338 is a substantially
toroidal member arranged about threaded rod 316 and arranged to
rotate freely in place and maintain position in first axial
direction AD1. This free rotation can be accomplished by leaving
the inner circumferential surface of second fixed collar 338 free
of threading, such that the threading of threaded rod 316 cannot
engage with and influence second fixed collar 338. Additionally, a
locking mechanism, i.e., locking mechanism 348 (not shown),
discussed infra, can be used to prevent second fixed collar 338
from translating about threaded rod 316 in first axial direction
AD1 and/or second axial direction AD2. Alternatively, and although
not illustrated in the figures, the inner circumferential surface
of second fixed collar 338 can contain an annular protrusion
arranged to fit within and slidingly engage with a corresponding
annular recess at a fixed axial position on the outer
circumferential surface of threaded rod 316.
[0078] Third arm 340 is pivotably connected between second fixed
collar 338 and superior plate 312. One end of third arm 340 is
pivotably connected to a protrusion on the inner surface of
superior plate 312 which can comprise a pin arranged to allow third
arm 340 to pivot with respect to superior plate 312. The other end
of third arm 340 is pivotably connected to a protrusion on the
outer circumferential surface of second fixed collar 338 which can
comprise a pin arranged to allow third arm 340 to pivot with
respect to second fixed collar 338. Third strut 342 is pivotably
connected between second threaded collar 336 and third arm 340. One
end of third strut 342 is pivotably connected to a protrusion on
the outer circumferential surface of second threaded collar 336
which can comprise a pin arranged to allow third strut 342 to pivot
with respect to second threaded collar 336. The other end of third
strut 342 is pivotably connected to third arm 340 which can
comprise a pin arranged to allow third strut 342 to pivot with
respect to third arm 340.
[0079] Fourth arm 344 is pivotably connected between second fixed
collar 338 and inferior plate 314. One end of fourth arm 344 is
pivotably connected to a protrusion on the inner surface of
inferior plate 314 which can comprise a pin arranged to allow
fourth arm 344 to pivot with respect to inferior plate 314. The
other end of fourth arm 344 is pivotably connected to a second
protrusion on the outer circumferential surface of second fixed
collar 338 which can comprise a pin arranged to allow fourth arm
344 to pivot with respect to second fixed collar 338. Fourth strut
346 is pivotably connected between second threaded collar 336 and
fourth arm 344. One end of fourth strut 346 is pivotably connected
to a second protrusion on the outer circumferential surface of
second threaded collar 336 which can comprise a pin arranged to
allow fourth strut 346 to pivot with respect to second threaded
collar 336. The other end of fourth strut 346 is pivotably
connected to fourth arm 344 which can comprise a pin arranged to
allow fourth strut 346 to pivot with respect to fourth arm 344.
[0080] Seventh arm 366 is pivotably connected between second fixed
collar 338 and superior plate 312. One end of seventh arm 366 is
pivotably connected to a protrusion on the inner surface of
superior plate 312 which can comprise a pin arranged to allow
seventh arm 366 to pivot with respect to superior plate 312. The
other end of seventh arm 366 is pivotably connected to a third
protrusion on the outer circumferential surface of second fixed
collar 338 which can comprise a pin arranged to allow seventh arm
366 to pivot with respect to second fixed collar 338. Seventh strut
368 is pivotably connected between second threaded collar 336 and
seventh arm 366. One end of seventh strut 368 is pivotably
connected to a third protrusion on the outer circumferential
surface of second threaded collar 336 which can comprise a pin
arranged to allow seventh strut 368 to pivot with respect to second
threaded collar 336. The other end of seventh strut 368 is
pivotably connected to seventh arm 366 which can comprise a pin
arranged to allow seventh strut 368 to pivot with respect to
seventh arm 366.
[0081] Eighth arm 370 is pivotably connected between second fixed
collar 338 and inferior plate 314. One end of eighth arm 370 is
pivotably connected to a protrusion on the inner surface of
inferior plate 314 which can comprise a pin arranged to allow
eighth arm 370 to pivot with respect to inferior plate 314. The
other end of eighth arm 370 is pivotably connected to a fourth
protrusion on the outer circumferential surface of second fixed
collar 338 which can comprise a pin arranged to allow eighth arm
370 to pivot with respect to second fixed collar 338. Eighth strut
372 is pivotably connected between second threaded collar 336 and
eighth arm 370. One end of eighth strut 372 is pivotably connected
to a fourth protrusion on the outer circumferential surface of
second threaded collar 336 which can comprise a pin arranged to
allow eighth strut 372 to pivot with respect to second threaded
collar 336. The other end of eighth strut 372 is pivotably
connected to eighth arm 370 which can comprise a pin arranged to
allow eighth strut 372 to pivot with respect to eighth arm 370.
[0082] Locking mechanism 348 (not shown) can be arranged about
threaded rod 316 and be positioned axially adjacent to second fixed
collar 338 in the first axial direction AD1 and/or the second axial
direction AD2. As second fixed collar 338 does not have internal
threading, locking mechanism 348 prevents second fixed collar 338
from translating about threaded rod 316 in first axial direction
AD1 and/or second axial direction AD2. In an example embodiment,
locking mechanism 348 is a lock washer, a crimp ring retainer, or a
serrated lock washer. However, it should be appreciated that
locking mechanism 348 can be any mechanism suitable for preventing
axial translation about a rod. It should be appreciated that
although first threaded collar 322 and second threaded collar 336
are positioned such that each translates in the same axial
direction, they could be positioned such that they each translate
in opposing directions. The opposing movement of first threaded
collar 322 and second threaded collar 336 could be achieved by
having opposing threading on their respective inner circumferential
surfaces, or the threaded collars could have identical threading
and first end 318 of threaded rod 316 could comprise helical
threading of a first direction while second end 320 of threaded rod
316 could comprise helical threading of a second direction opposite
the first direction.
[0083] During surgery, and after device 100 containing expansion
mechanisms 306 is implanted in situ within disc space 12, a surgeon
can apply torque to threaded rod 316 via any device that imparts
rotational force (e.g., a screw driver or impact driver). As
threaded rod 316 rotates in first rotational direction RO1, second
fixed collar 338 maintains a fixed axial position about threaded
rod 316 as it is confined by locking mechanism 348. Additionally,
as threaded rod 316 rotates in first rotational direction RO1, the
inner circumferential threading of second threaded collar 336
engages with the helical threading of threaded rod 316 causing
second threaded collar 336 to translate in first axial direction
AD1. The translational motion imparted to second threaded collar
336, in conjunction with the lack of translational motion of second
fixed collar 338, imparts a force upon third strut 342, fourth
strut 346, seventh strut 368, and eighth strut 372, which in turn
impart a force upon third arm 340 and seventh arm 366 in first
radial direction RD1, and fourth arm 344 and eighth arm 370 in
second radial direction RD2.
[0084] Although not illustrated, First arm 326, second arm 330,
third arm 340, fourth arm 344, fifth arm 358, sixth arm 362,
seventh arm 366, and eighth arm 370, each contain a recess, i.e.,
first recess 350, second recess 352, third recess 354, fourth
recess 356, fifth recess 374, sixth recess 376, seventh recess 378,
and eight recess 380, respectively. When expansion mechanism 306 is
in a collapsed state as illustrated in FIG. 19, first recess 350 of
first arm 326 is arranged to receive first strut 328 such that
first strut 328 is completely nested within first recess 350.
Similarly, second recess 152, third recess 154, fourth recess 156,
fifth recess 374, sixth recess 376, seventh recess 378, and eight
recess 380, are all arranged to receive second strut 332, third
strut 342, fourth strut 346, fifth strut 360, sixth strut 364,
seventh strut 368, and eighth strut 372 respectively, such that
each strut is completely nested within a respective recess.
Alternatively, each strut could contain a recess arranged to
receive each arm such that each arm is nested completely within the
recess of each respective strut.
[0085] Thus it is seen that the objects of the invention are
efficiently obtained, although changes and modifications to the
invention should be readily apparent to those having ordinary skill
in the art, which changes would not depart from the spirit and
scope of the invention as claimed.
LIST OF REFERENCE NUMBERS
[0086] 10 Spinal column [0087] 12 Disc space [0088] C1-C7 Cervical
vertebrae [0089] T1-T9 Thoracic vertebrae [0090] L1-L5 Lumbar
vertebrae [0091] S Sacrum [0092] C Coccyx [0093] D.sub.L1-L2 Disc
[0094] D.sub.L2-L3 Disc [0095] D.sub.L3-L4 Disc [0096] D.sub.L4-L5
Disc [0097] F Facet [0098] FJ Facet joint [0099] H.sub.1 Collapsed
height [0100] H.sub.2 Expanded height [0101] SP Spinous process
[0102] TP Transverse process [0103] IF Intervertebral foramen
[0104] A Annulus [0105] AR Axis of rotation [0106] N Nucleus [0107]
NC Neural canal [0108] H.sub.1 Unexpanded height [0109] H.sub.2
Expanded height [0110] RD1 Rotational direction [0111] RD2
Rotational direction [0112] AD1 Axial direction [0113] AD2 Axial
direction [0114] RO1 Radial direction [0115] RO2 Radial direction
[0116] 100 Device [0117] 102 Superior component [0118] 104 Inferior
component [0119] 106 Expansion mechanism [0120] 108 First aperture
[0121] 110 Second aperture [0122] 112 Superior plate [0123] 114
Inferior plate [0124] 116 Threaded rod [0125] 118 First end [0126]
120 Second end [0127] 122 First threaded collar [0128] 124 First
fixed collar [0129] 126 First arm [0130] 128 First strut [0131] 130
Second arm [0132] 132 Second strut [0133] 134 Locking mechanism
[0134] 136 Second threaded collar [0135] 138 Second fixed collar
[0136] 140 Third arm [0137] 142 Third strut [0138] 144 Fourth arm
[0139] 146 Fourth strut [0140] 148 Locking mechanism [0141] 150
First recess [0142] 152 Second recess [0143] 154 Third recess
[0144] 156 Fourth recess [0145] 206 Expansion mechanism [0146] 212
Superior plate [0147] 214 Inferior plate [0148] 216 Threaded rod
[0149] 218 First end [0150] 220 Second end [0151] 222 First
threaded collar [0152] 224 Fixed collar [0153] 226 First arm [0154]
228 First strut [0155] 230 Second arm [0156] 232 Second strut
[0157] 234 Locking mechanism [0158] 236 Second threaded collar
[0159] 240 Third arm [0160] 242 Third strut [0161] 244 Fourth arm
[0162] 246 Fourth strut [0163] 250 First recess [0164] 252 Second
recess [0165] 254 Third recess [0166] 256 Fourth recess [0167] 306
Expansion mechanism [0168] 312 Superior plate [0169] 314 Inferior
plate [0170] 316 Threaded rod [0171] 318 First end [0172] 320
Second end [0173] 322 First threaded collar [0174] 324 First fixed
collar [0175] 326 First arm [0176] 328 First strut [0177] 330
Second arm [0178] 332 Second strut [0179] 334 Locking mechanism
[0180] 336 Second threaded collar [0181] 338 Second fixed collar
[0182] 340 Third arm [0183] 342 Third strut [0184] 344 Fourth arm
[0185] 346 Fourth strut [0186] 348 Locking mechanism [0187] 350
First recess [0188] 352 Second recess [0189] 354 Third recess
[0190] 356 Fourth recess [0191] 358 Fifth arm [0192] 360 Fifth
strut [0193] 362 Sixth arm [0194] 364 Sixth strut [0195] 366
Seventh arm [0196] 368 Seventh strut [0197] 370 Eighth arm [0198]
372 Eighth strut [0199] 374 Fifth recess [0200] 376 Sixth recess
[0201] 378 Seventh recess [0202] 380 Eighth recess
* * * * *