U.S. patent application number 15/938083 was filed with the patent office on 2019-01-03 for intervertebral implant device with lordotic expansion.
This patent application is currently assigned to Amendia, Inc.. The applicant listed for this patent is Amendia, Inc.. Invention is credited to Brion Daffinson, Austin Howell, Chase Thornburg.
Application Number | 20190000646 15/938083 |
Document ID | / |
Family ID | 62046550 |
Filed Date | 2019-01-03 |
![](/patent/app/20190000646/US20190000646A1-20190103-D00000.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00001.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00002.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00003.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00004.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00005.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00006.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00007.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00008.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00009.png)
![](/patent/app/20190000646/US20190000646A1-20190103-D00010.png)
View All Diagrams
United States Patent
Application |
20190000646 |
Kind Code |
A1 |
Daffinson; Brion ; et
al. |
January 3, 2019 |
INTERVERTEBRAL IMPLANT DEVICE WITH LORDOTIC EXPANSION
Abstract
An expandable interbody fusion implant device has a frame, two
ramp assemblies, a threaded drive shaft and at least one base
plate, preferably two. The frame has a first lateral side and a
second lateral side and a distal end and a proximal end. Each ramp
assembly has a translating ramp with a threaded opening, a first
pivoting hinged ramp and a second pivoting hinged ramp. Each base
plate is hinged to a first lateral side of the frame. Each base
plate is hinged to the distal ramp assembly and the proximal ramp
assembly at an end of one of said pivoting hinged ramps of each
ramp assembly. The drive shaft has a distal drive shaft component
having threads for translating the distal ramp assembly and a
proximal drive shaft component having threads for translating the
proximal ramp assembly.
Inventors: |
Daffinson; Brion; (Marietta,
GA) ; Howell; Austin; (Decatur, GA) ;
Thornburg; Chase; (Cumming, GA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Amendia, Inc. |
Marietta |
GA |
US |
|
|
Assignee: |
Amendia, Inc.
Marietta
GA
|
Family ID: |
62046550 |
Appl. No.: |
15/938083 |
Filed: |
March 28, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15635657 |
Jun 28, 2017 |
9962272 |
|
|
15938083 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2002/30265
20130101; A61F 2002/30538 20130101; A61F 2002/30556 20130101; A61B
17/7059 20130101; A61F 2/4611 20130101; A61F 2002/30507 20130101;
A61F 2002/30578 20130101; A61B 17/8042 20130101; A61F 2002/3054
20130101; A61F 2/30749 20130101; A61F 2002/30471 20130101; A61F
2002/30593 20130101; A61B 17/8057 20130101; A61F 2/447 20130101;
A61F 2002/30261 20130101; A61F 2002/30411 20130101; A61F 2002/4627
20130101; A61F 2002/30383 20130101 |
International
Class: |
A61F 2/46 20060101
A61F002/46; A61B 17/80 20060101 A61B017/80; A61B 17/70 20060101
A61B017/70; A61F 2/44 20060101 A61F002/44 |
Claims
1. An expandable interbody fusion implant device comprises: a frame
having a first lateral side and a second lateral side and a distal
end and a proximal end; two ramp assemblies, one being a distal
ramp assembly and the other a proximal ramp assembly, each ramp
assembly has a translating ramp with a threaded opening, a first
pivoting hinged ramp and a second pivoting hinged ramp, each
pivoting hinged ramp being pivotably movable about a pinned end by
a pivot pin oriented parallel to the second lateral side; a first
and a second base plate disposed between the distal end and the
proximal end of the frame, each base plate being hinged to a first
lateral side of the frame, the first base plate overlying the
second base plate, each base plate being hinged to the distal ramp
assembly and the proximal ramp assembly at the pivoting end of one
of said pivoting hinged ramps of each ramp assembly, each base
plate being pivotably affixed to and movable relative to the
pivoting hinged ramps, each base plate having pockets for holding
each pivoting hinged ramp at the pinned end transverse to the
second lateral side; a threaded drive shaft pinned to the proximal
end of the frame, the drive shaft having a distal drive shaft
component having threads for translating the distal ramp assembly
and a proximal drive shaft component having threads for translating
the proximal ramp assembly, each drive shaft component being
coupled to the other, the proximal drive shaft component being
affixed to the frame at the proximal end of the frame; and wherein
rotation of the drive shaft drives the translating ramp of the
distal ramp assembly and the translating ramp of the proximal ramp
assembly simultaneously in opposite directions as each of the first
pivoting hinged ramp and the second pivoting hinged ramp pivots
being moved by the translating ramps wherein each translating ramp
has an exterior lift surface to guide and support the pivoting
hinged ramps during expansion or contraction of the base plates,
and wherein each pivoting hinged ramp has a bearing support surface
configured to slide on the exterior lift surface of the translating
ramp as the pivoting hinged ramp is moved by the translating ramp
to selectively expand or contract a distance between the two base
plates laterally relative the second lateral side of the frame,
simultaneous rotation of both distal and proximal drive shaft
components drives the distal and proximal ramps to selectively
expand or contract a distance between both first and second base
plates to a selected inclination of the first and second base
plates relative to the frame over a range of lordotic angles.
2. (canceled)
3. The expandable interbody fusion implant device of claim 1
wherein during expansion of the base plates the distal ramp
assembly moves directionally toward the distal end of the frame on
rotation of the distal drive shaft component as the proximal ramp
assembly simultaneously moves directionally toward the proximal end
of the frame on rotation of the proximal drive shaft component,
increasing the inclination of the base plates relative to the
frame.
4. (canceled)
5. The expandable interbody fusion implant device of claim 1
wherein each pivoting hinged ramp bearing support surface is
complimentary to the exterior lift surface.
6. The expandable interbody fusion implant device of claim 5
wherein the complimentary surface of both the pivoting hinged ramp
bearing support surface and the exterior lift surface being
inclined with a sloped flat feature.
7. The expandable interbody fusion implant device of claim 1
wherein each translating ramp has a pair of opposing sides, each
side has a pair of guide channels or grooves configured to receive
a projecting rail positioned inside the frame along each first and
second lateral side of the frame.
8. The expandable interbody fusion implant device of claim 7
wherein each base plate has pockets to which the pivoting hinged
ramps are pinned and each translating ramp has a hinge guide
channel or hinge guide groove for receiving and guiding one of the
pivoting hinged ramps, each pivoting hinged ramp has a lateral side
keyed into the hinge guide channel or hinge guide groove.
9. The expandable interbody fusion implant device of claim 1
wherein the distal end of the frame has a tapered end configured to
facilitate insertion between vertebral bodies.
10. The expandable interbody fusion implant device of claim 1
wherein the proximal end of the frame has an opening for receiving
an end of the threaded drive shaft and further has the first
lateral side with slotted channels to receive a hinge pin fixed to
the first or second base plates, the hinge pins configured to allow
the base plates to pivot relative to the frame during expansion or
contraction.
11. The expandable interbody fusion implant device of claim 10
wherein the first and second base plates each have at the proximal
end an end plate with a fastener opening for securing the implant
to a vertebral body, each end plate being integral to and movable
with the base plate during expansion or contraction.
12. The expandable interbody fusion implant device of claim 11
wherein each end plate further has a locking tab attached to the
end plate, the locking tab being rotatable to cover a portion of
the fastener from loosening after being affixed to a vertebral
body.
13. The expandable interbody fusion implant device of claim 1
wherein the base plates have a laterally inclined outer surface
configured to match or mimic a lordotic curvature of the lumbar
spine.
Description
[0001] The present invention is a division of co-pending U.S.
application Ser. No. 15/635,657 filed Jun. 28, 2017 entitled,
"Intervertebral Implant Device With Lordotic Expansion".
TECHNICAL FIELD
[0002] The present disclosure relates to an expandable interbody
fusion implant device with lordotic expansion and contraction for
implantation between vertebral bodies.
BACKGROUND OF THE INVENTION
[0003] Spinal stabilization can be achieved by providing an
interbody implant. Some of these implants are bone, PEEK (polyether
ether ketone), solid titanium or similar non-bone implant material
and some are hollow implants that provide for inclusion of a bone
graft or other suitable material to facilitate bony union of the
vertebrae.
[0004] Interbody implants can be inserted into the disc space
through an anterior, posterior or lateral approach. In some
systems, the implants are inserted into a bore formed between
adjacent vertebral bodies in the cortical endplates and can extend
into the cancellous bone deep to the cortical endplates. Implant
size is typically selected such that the implants force the
vertebrae apart to cause tensing of the vertebral annulus and other
soft tissue structures surrounding the joint space. Tensing the
soft tissues surrounding the joint space results in the vertebrae
exerting compressive forces on the implant to retain the implant in
place.
[0005] It has been found desirable to keep the surgical opening as
small as practical while still having sufficient room to insert the
implant device and the end of an elongated tool or insertion
instrument.
[0006] Advantageously, if the implant size could be reduced further
that would allow the surgical opening to be reduced; however, once
implanted the device needs to be expandable to provide sufficient
spacing of the vertebrae.
[0007] A whole class of expandable interbody implant devices have
been developed for this purpose. Some prior art devices use
hydraulic expansion or inflatable balloons. Some devices are
stackable elements piled on themselves to raise their height. Some
use rotatable screw jack designs. Some are wedges that have a fixed
hinged end and an opposite expandable end. Most of the rotatable
expandable devices using screw threads require the device to be
round cylinders or posts.
[0008] One of the problems of such devices is the amount of post
insertion manipulation required to reach a fully expanded properly
space height is tedious and time consuming. Secondly, additional
set screws or locking elements are often required to keep the
device at its proper size. Thirdly, the devices of a circular shape
are not the best fit for the adjacent vertebrae being spaced.
Fourth, most of the devices have the internal space occupied with
mechanisms limiting the amount of bone growth material available
for packing the implants.
[0009] The wedge type implants generally contact the bone on an
angle and expandable wedges when expanded simply expand on an angle
not parallel to the vertebrae surface. This places localized high
loading between the vertebrae because the wedge surfaces are not
parallel to the vertebrae.
[0010] In some cases of vertebral misalignment, a controlled
angulation of the implant device can be very beneficial to correct
a pre-existing condition. Accordingly, in those cases having a
wedge shape at a fixed angulation would mean the manufacturer would
be required to make many devices with pre-set angles to select
from. This simply is cost prohibitive.
[0011] Previous ramped methods of expansion limit the range of
expansion height, and therefore maximum angle, of the implant by
using ramped surfaces directly onto the base plate which contacts
the endplate of the vertebral body. Other expansion methods include
cylindrical gear drive features, hinged linkages, and cams/ramps
forcing base plate(s) apart through plastic deformation of the
material. The cylindrical gear drive features limit the amount of
bone graft space available within the interbody cage to promote
fusion, unsupported hinged linkages reduce load bearing surface
area and negatively affect the expansion strength and overall
strength of the interbody cage. Other devices use material
deformation which limits the amount of expansion capability and
reduces the structural integrity of the interbody cage. The present
invention overcomes all these deficiencies.
[0012] The present invention provides a device that can be expanded
angularly to allow the surgeon to choose the ideal lordotic angle
he wants to use to correct the spinal alignment.
[0013] These and other limitations in the prior art have been
corrected and solved by the present invention as disclosed
herein.
SUMMARY OF THE INVENTION
[0014] An expandable interbody fusion implant device has a frame,
two ramp assemblies, a threaded drive shaft and at least one base
plate, preferably two. The frame has a first lateral side and a
second lateral side and a distal end and a proximal end. The two
ramp assemblies include a distal ramp assembly and a proximal ramp
assembly. Each ramp assembly has a translating ramp with a threaded
opening, a first pivoting hinged ramp and a second pivoting hinged
ramp. The at least one, preferably two overlying base plates are
disposed between the distal end and the proximal end of the frame.
Each base plate is hinged to a first lateral side of the frame. A
first base plate overlies a second base plate. Each base plate is
hinged to the distal ramp assembly and the proximal ramp assembly
at an end of one of said pivoting hinged ramps of each ramp
assembly. The threaded drive shaft is pinned to the proximal end of
the frame. The drive shaft has a distal drive shaft component
having threads for translating the distal ramp assembly and a
proximal drive shaft component having threads for translating the
proximal ramp assembly. Each drive shaft component is coupled to
the other. The proximal drive shaft component is affixed to the
frame at the proximal end of the frame.
[0015] Rotation of the drive shaft drives the distal ramp assembly
and proximal ramp assembly simultaneously in opposite directions to
selectively expand or contract a distance between the two base
plates laterally relative the second lateral side of the frame.
This simultaneous rotation of both distal and proximal drive shaft
components drives the distal and proximal ramps selectively expands
or contracts a distance between both first and second base plates
to a selected inclination of the first and second base plates
relative to the frame over a range of lordotic angles.
[0016] Each translating ramp has an exterior lift surface to guide
and support the pivoting hinged ramps during expansion or
contraction of the base plates. During expansion of the base plates
the distal ramp assembly moves directionally toward the distal end
of the frame on rotation of the distal drive shaft component as the
proximal ramp assembly simultaneously moves directionally toward
the proximal end of the frame on rotation of the proximal drive
shaft component, increasing the inclination of the base plates
relative to the frame. This device stops expansion when each
translating ramp contacts the distal and proximal wall of the
frame. Each pivoting hinged ramp has a bearing support surface
configured to slide on the exterior lift surface of the translating
ramp. Each pivoting hinged ramp bearing support surface is
complimentary to the exterior lift surface, the complimentary
surface of each being inclined with a sloped flat feature.
[0017] Each translating ramp has a pair of opposing sides, each
side has a pair of guide channels or grooves configured to receive
a projecting rail positioned inside the frame along each first and
second lateral side of the frame. Each base plate has pockets to
which the pivoting hinged ramps are pinned and each translating
ramp has a hinge guide channel or hinge guide groove for receiving
and guiding one of the pivoting hinged ramps. Each pivoting hinged
ramp has a lateral side keyed into the hinge guide channel or hinge
guide groove.
[0018] The distal end of the frame has a tapered end configured to
facilitate insertion between vertebral bodies. The proximal end of
the frame has an opening for receiving an end of the threaded drive
shaft, and further has the first lateral side with slotted channels
to receive a hinge pin fixed to the first or second base plates,
the hinge pins configured to allow the base plates to pivot
relative to the frame during expansion or contraction.
[0019] In still another embodiment, the first and second base
plates each have at the proximal end an end plate with a fastener
opening for securing the implant to a vertebral body. Each end
plate is integral to and movable with the base plate during
expansion or contraction. Each end plate further has a locking tab
attached to the end plate, the locking tab being rotatable to cover
a portion of the fastener from loosening after being affixed to a
vertebral body. Preferably, the base plates have a laterally
inclined outer surface configured to match or mimic a lordotic
curvature of the lumbar spine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The invention will be described by way of example and with
reference to the accompanying drawings in which:
[0021] FIG. 1 is a perspective view of the expandable implant
device of a preferred embodiment made in accordance with the
present invention shown in a contracted non-expanded position.
[0022] FIG. 1A is an alternative embodiment of the present
invention without end plates and fasteners shown in a contracted
position.
[0023] FIG. 2 is a side view of the expandable implant device taken
from FIG. 1.
[0024] FIG. 3A is a perspective view of the device of FIG. 1 shown
expanded.
[0025] FIG. 3B is the side view taken from FIG. 3A with threaded
fasteners installed in the proximal end of each first and second
base plate.
[0026] FIG. 4A is a proximal end view of the device of FIG. 1 shown
contracted without fasteners.
[0027] FIG. 4B is a proximal end view taken from FIG. 4A with
fasteners.
[0028] FIG. 4C is a proximal end view taken from FIG. 4B with
threaded fasteners installed in the proximal end of each first and
second base plate with the device shown expanded.
[0029] FIG. 5A is a perspective exploded view of the device of FIG.
1 shown without the fasteners.
[0030] FIG. 5B is a side view of the device taken from FIG. 5A
showing the frame and the drive shaft and translating ramp
assemblies assembled.
[0031] FIG. 5C is a side view taken of the proximal end of the
drive shaft and proximal translating ramp and the frame.
[0032] FIG. 5D is an exploded perspective view of the device of
FIG. 5A with the proximal portion of the drive shaft prior
installed in the proximal end of the frame and the pins not yet
installed and the distal drive shaft component and distal ramp
shown above the frame.
[0033] FIG. 6A is an exploded side view of the device of the
present invention as a final assembly step showing hinge pins for
securing the base plates to the frame.
[0034] FIG. 7A is a side cross-sectional view of the device of the
present invention with the drive shaft rotated to a fully
contracted position.
[0035] FIG. 7B is a side cross-sectional view of the device of the
present invention with the drive shaft expanded.
[0036] FIG. 8A is an end cross-sectional view of the device of the
present invention with the ramp assembly shown with drive shaft
expanded.
[0037] FIGS. 9A, 9B and 9C are isometric views of the alternative
embodiment device with no end plates shown contracted partially
expanded and fully expanded.
[0038] FIGS. 10A and 10B are side views of the device of 1A shown
contracted and fully expanded, respectively.
[0039] FIGS. 11A and 11B are cross sectional views of the device of
FIG. 1A taken from FIGS. 10A and 10B, 11A from 10A and 11B from
10B.
[0040] FIGS. 12A and 12B are distal end views, 12A shown contracted
and 12B shown expanded.
[0041] FIGS. 13A and 13B are proximal end views, 13A shown
contracted and 13B shown expanded.
[0042] FIGS. 14A and 14B are top views, 14A shown contracted and
14B shown expanded.
[0043] FIG. 15A is a cross-sectional view of the device of the
present invention in a contracted position.
[0044] FIG. 15B is a cross-sectional view of the device of the
present invention in an expanded position.
[0045] FIG. 16 is a side view of a third embodiment of the
invention wherein only a single hinge base plate is shown attached
to the frame and the frame has a fixation end plate at the proximal
end.
[0046] FIG. 17 is an exemplary illustration of the device implanted
between two adjacent vertebral bodies.
DETAILED DESCRIPTION OF THE INVENTION
[0047] The purpose of the present invention is to promote spinal
fusion with distraction and/or alignment correction of vertebral
bodies by implanting the interbody device 10 and expanding the base
plates 20, 40 to the appropriate height and angle by controlling
fine height adjustment of one side of the implant (anterior side),
increasing the lordotic angle. The optional incorporated fixation
end plates which expand along with the base plates 20, 40 may be
used as in FIG. 1 or may not be used as in FIG. 1A to accept a
screw or fastener and lock for fixation of the interbody.
[0048] The intervertebral implant device with lordotic expansion of
the present invention, hereinafter described as an expandable
interbody fusion implant device 10, has a frame 60, two ramp
assemblies, 34A, 35A and two overlying base plates 20, 40 driven by
a threaded drive shaft 50 having two coupled drive shaft components
51, 52; as illustrated in FIGS. 1 and 1A. As illustrated in the
preferred embodiment of FIG. 1, each base plate 20, 40 has a
fixation end plate 21, 41 with an opening 25, 45 for receiving a
threaded fastener 100 for attachment to a vertebral body. A locking
tab 70 is provided. In FIG. 1A, an alternative embodiment 10A of
the device 10 is illustrated without fixation end plates 21, 41 or
threaded fasteners 100. In all other respects the devices 10, 10A
are the same.
[0049] With reference to FIGS. 1 and 2, the device 10, 10A shows
the frame 60 having a distal end 62 and a proximal end 61. The two
ramp assemblies 34A, 35A include a distal translating ramp 35 and a
proximal translating ramp 34 respectively, and further have a first
pivoting hinged ramp 31 and a second pivoting hinged ramp 33 held
by pins 85 in pockets or recesses in each base plate 20, 40. The
two overlying base plates 20, 40 are disposed between the distal
end 62 and the proximal end 61. The first base plate 20 overlies
the second base plate 40 with the frame 60 interposed between. Each
base plate 20, 40 is hinged to a distal ramp assembly 35A and the
proximal ramp assembly 34A at an end of one of the said pivoting
hinged ramps 31, 33 of each ramp assembly 34A, 35A by the pivoting
hinged ramps held by pins 85 in the pockets or recesses of each
base plate and further hinged with pins 82 along a first lateral
side of the frame 60. Each base plate 20, 40 being pivotally
moveable about the hinge of the frame 60. The drive shaft 50
include a distal drive shaft component 52 for translating the
distal ramp assembly 35A and a proximal drive shaft component 51
for translating the proximal ramp assembly 34A. The drive shaft 50
is affixed to the frame 60 at the proximal end with pins 53.
[0050] As shown in FIGS. 1 and 2, the implant device 10 is shown in
a fully contracted position, this position is most suitable for
insertion as it provides the lowest height between the opposing
base plates 20, 40. As shown, the distal end 62 has a chamfered
leading end surface further reducing the cross section as it enters
between the intervertebral spaces providing a nice leading nose end
for insertion. At the proximal end of the implant device 10, each
base plate 20, 40 respectively has fixation end plates 21 and 41.
These fixation end plates 21, 41 each are provided with a through
hole 25 for receiving a threaded fastener 100.
[0051] With reference to FIGS. 3A and 3B, the implant device 10 is
shown where the threaded drive shaft 50 has been rotated, the
distal drive shaft component 52 has threads 59 engage threads 95 in
the translating ramp 35 that cause the distal ramp assembly 35A to
be moved towards the distal end of the frame 62. When this occurs,
the translating ramp 35 of the distal ramp assembly 35A moves the
pivoting hinged ramps 31 and 33 along an outer surface of the
translating ramp 35 following the contour of the outer surface.
Simultaneously, when this drive shaft 50 is rotationally driven it
rotates the proximal drive shaft component 51 causing the base
plates 20, 40 both to be expanded increased in height from the
contracted state to an expanded state as the base plates 20, 40
pivot. The drive shaft 50 is assembled from two components 51, 52
and the proximal component 51 is pinned with pins 53 into the frame
60 at the proximal end of the interbody to maintain positioning and
prevent translation. The drive shaft 50 threads into both the
distal translating/expanding ramp 35 and the proximal
translating/expanding ramp 34 to drive both ramp assemblies
simultaneously. To accomplish this movement, the distal drive shaft
component 52 has threads 59 opposite to the proximal drive shaft
component 51 threads 58, one thread being left handed the other
thread right handed.
[0052] This increase in height can occur in small increments
anywhere dependent on the amount of the rotation of the drive shaft
50 and this rotation achieves a maximum level when the translating
ramp 34, 35 contacts the distal or proximal wall of the frame 60.
In the fully expanded condition, the lateral side of each base
plate is shown elevated relative to the frame. This can best be
seen in FIG. 3B from a side view or 4C from a front view. Threaded
fasteners 100 can be inserted through the through holes 25 in both
the first fixation end plate 21 and the second fixation end plate
41 of the first base plate 20 and the second base plate 40
respectively at any selected angle or expansion. FIG. 4A best shows
the through holes 25 without the fasteners 100. FIGS. 4B and 4C
show the end view of the device 10 in the contracted and fully
expanded positions.
[0053] With reference to FIGS. 5A-5D, various exploded views of the
components of the implant device 10 are shown. With reference to
FIGS. 5A, 5B the ramp assemblies 34A, 35A are shown as individual
components, the translating ramps 34, 35 and the pivoting hinged
ramps 31, 33 respectively are illustrated. As shown the translating
ramps 34, 35 have an outer contour 38 on both an upper and a lower
surface of each translating ramp 34, 35 and have a dovetail key or
projection 37 on each ramp 34, 35. This key 37 allows lateral sides
of the pivoting hinged ramps 31 and 33 with a grooved keyway to
enter in a dovetail configuration and lock into the translating
ramps 34, 35 while maintaining an ability to slide relative to the
other. The inner bearing surface 39 of both the pivoting hinged
ramps 31, 33 ride on the outer lift surface 38 of the translating
ramps 34 and 35 respectively. In this fashion, during the elevation
of the implant 10 from contracted to expanded, the pivoting hinged
ramps 31, 33 rest securely on the lift surface 38 on both lateral
sides of the translating ramp 34, 35 and the base plates 20, 40
hinged to the pivoting hinged ramps 31, 33 at both lateral ends are
fully supported across the lateral width of the implant device 10
as the pivoting hinged ramps 31, 33 press against the respective
pockets of each base plate. In this construction, there are no gaps
between the base plates 20 and 40 as the lift surfaces 38 of the
translating ramps 34, 35 and bearing surfaces 39 of the pivoting
hinged ramps 31, 33 as well as upon expansion the hinged ramps
contact the pockets of the bases 20, 40 as shown best shown in FIG.
8D. All load supporting elements are moved into contact during
expansion. Accordingly, the device 10, 10A is extremely rigid
between the vertebral bodies and capable of supporting large loads
without deflection or deformation when expanded. The hinged lateral
side of the base plates 20, 40 being fully supported by the frame
60 and the expanding lateral side are both fully supported. With
reference to FIG. 5C, the frame 60, shown slightly below the
proximal translation ramp 34 and the proximal drive shaft component
51, the frame 60 is a singular piece having a distal end 62 that
has a tapered exterior surface to facilitate insertion.
[0054] The fixation end plates 21, 41 accept a locking tab 70 used
to lock the bone screws 100 to the fixation end plates 21, 41. The
base plates 20, 40 are pinned with pins 85 to all four pivoting
hinged ramps 31, 33 at the hinged points to maintain a bearing
surface between the pivoting hinged ramps 31, 33 and base plates
20, 40 as well as between the pivoting hinged ramps 31, 33 and
translating ramps 34, 35 at all interbody states. The base plates
20, 40 are also assembled to the frame 60 with a hinge pin 82 for
each top and bottom base plates 20, 40 as shown. The base plates
20, 40 feature a contoured surface 20C, 40C to match the surface of
the vertebral body endplates. The tangent planes of the base
plates' 20, 40 contoured surfaces can be either parallel or
intersecting. A bone screw or threaded fastener 100 can be inserted
into each fixation end plates 21, 41 through the screw holes 25, 45
located on the integrated fixation end plates 21, 41 as shown. The
alternative embodiment device 10A does not include an integrated
fixation plate, as shown in FIG. 1A.
[0055] Each translating ramp 34, 35 has a groove 37 on each side
that slides over the rails 67 on each lateral interior side of the
frame 60, as shown with a gap between the rails 67 is provided to
allow the assembly to the frame 60. These features increase the
support and rigidity of the device at all positions of expansion.
The base plates 20, 40 also have depressions or pockets into which
the pivoting hinged ramps 31, 33 fit and are pinned by the pins
85.
[0056] With reference to FIG. 5D, the frame 60 is shown with the
proximal drive shaft component 51 positioned into the proximal end
of the frame 60 with the proximal translation ramp 34 threaded onto
the proximal drive shaft component 51. Shown above the frame 60 are
a pair of pins 53 that are used to secure the proximal drive shaft
component 51 in grooves 53A to the frame 60. Also shown above the
frame 60 is the distal drive shaft component 52 with threads 59.
The distal drive shaft component 52 has a hexagonal head 56A. The
distal translating ramp 35 is shown adjacent the distal drive shaft
component 52. The distal translating ramp 35 is shown with each
lateral side having a groove 37. These grooves 37 fit onto rails 67
on the interior walls of the frame 60.
[0057] With reference to FIG. 6A, the distal drive shaft component
52 is shown connected to the female 12-point socket 56B of the
proximal drive shaft component 51 coupling the two drive shaft
components 51, 52 together to form the drive shaft 50. The base
plates 20, 40 are shown with openings to receive hinge pins 82,
each hinge pin 82 connects a base plate 20, 40 to the frame 60
allowing the base plates 20, 40 to pivotally move relative to the
frame 60 secured by the hinge pins 82.
[0058] With reference to FIGS. 7A and 7B, cross sectional views of
the device 10 are shown. In FIG. 7A, the device 10 is shown in the
contracted position with the translating ramps 34, 35 positioned
closer to the midline or center of the device or frame 60. In this
position, the pivoting hinged ramps 31, 33 are positioned on the
lower or contracted positon and therefore are shown hanging down
and bearing against the lift surfaces 38 of the translating ramps
34, 35 respectively. With reference to FIG. 7B, as the drive shaft
50 is rotated, the translating ramps 34, 35 move outwardly toward
the proximal and distal ends, respectively. As this occurs, the
bearing or support surface 38 is increasing in height forcing the
pivoting hinged ramps 31, 33 to elevate as they ride along this
surface 38 tending to push the base plates 20, 40 pivotally about
the pivot or hinge pin 82 and increasing the distance between the
base plates 20, 40. When this occurs, the distal end 62 is shown
exposed with the plates shown extended above that end of the device
10, 10A.
[0059] With reference to FIG. 8A, an end view of the device is
illustrated in the fully expanded position. As shown, the
translating ramp 34, 35 is shown positioned over the drive shaft 50
in an extended positon. When this occurs, the base plates 20, 40
pivot about the hinge pins 82 securely fixed to the frame 60. The
side opposite the hinge pins 82 has an increased expanded height
between the base plates 20, 40 relative to the frame 60. When this
occurs, the pivoting hinged ramps 31, 33 are shown almost
horizontal abutting the pocket of the base plates 20, 40. Hinge 31
shown in the upper position, 33 in a lower position pinned by pins
85 to the base plates. As shown, the pivoting hinged ramps 31, 33
are dovetailed and keyed onto the translating ramps 34, 35 in this
elevated position and during expansion, the translating ramps 34,
35 slide along the dovetail as the pivoting hinged ramps 31, 33
elevate increasing the expansion height of the device 10.
[0060] With reference to FIGS. 9A and 9B, the alternative device
10A without fixation end plates is illustrated. In FIG. 9A, the
device 10A is shown in the contracted position. In FIG. 9B, the
device 10A is shown in the expanded position. All the elemental
components are otherwise the same as in the device 10 previously
discussed. As shown in FIG. 9A, the translating ramps 34, 35 slide
along the rail 67 of the frame 60 by use of a groove 37 on each
side of the translating ramps 34, 35. When the device 10A is in the
contracted position, the translating ramps 34, 35 are moved towards
the center of the device 10A and the threads 58, 59 of the drive
shaft are basically covered by the translating ramps 34, 35. When
the device 10A is in the expanded position, as shown in FIG. 9B the
threads 58, 59 are exposed showing the translating ramps 34, 35
have moved outwardly, the distal translating ramp 35 towards the
distal end and the proximal translating ramp 34 towards the
proximal end of the device 10A. When this occurs, the device 10A is
in the elevated position. The surgeon can select any position from
fully contracted to fully expanded or anywhere in between to choose
the desired angle and increase in elevation of the device 10A as it
is expanded. FIG. 9C best illustrates how the base plates 20, 40 on
the side of the device 10A opposite the hinged side expand away
from the frame 60 in the expanded position.
[0061] With reference to FIG. 10A, a side view of the device 10A is
illustrated in the contracted position. With reference to FIG. 10B,
the same device 10A is shown in the expanded position.
[0062] With reference to FIG. 11A, the device 10A in the contracted
position is shown in cross section. In FIG. 11B, the device 10A is
shown in cross section in the expanded position.
[0063] FIG. 12A shows a front view of the device 10A showing the
distal end 62 and clearly showing the hinge pins 82 on the hinged
side of the device 10A. FIG. 12B is the same frontal view showing
the distal end 62 with the base plates 20, 40 shown in the expanded
position.
[0064] FIG. 13A shows the proximal end of the device 10A, as shown
the proximal end of the device has a torque driving element 57 to
which a torque driving insertion tool can be inserted to move the
drive shaft 50. The torque driving element 57 provides the ability
to rotate the drive shaft 50 to expand or contract the device. When
doing so, a torque driving insertion tool is inserted into the
torque driving element 57 to engage the drive shaft 50 and provide
rotational movement of the drive shaft 50. When the drive shaft 50
is rotated as shown in FIG. 13B, the device 10A is in the expanded
position.
[0065] FIG. 14A is a top view of the device 10A shown in the
contracted position with the threads 58, 59 not visible when the
translating ramps 34, 35 are in the contracted position. FIG. 14B
is a top view of the device 10A shown in the expanded position with
the threads 58, 59 clearly visible as the translating ramps 34, 35
are moved towards the ends of the device 10A.
[0066] In FIG. 15A a cross sectional view is shown wherein it is
clearly seen where the translating ramps 34, 35 are positioned
relative to the threads 58, 59 of the drive shaft 50. FIG. 15B,
when in an expanded position shows the translating ramps 34, 35 are
moved towards the ends of the device 10A.
[0067] Interestingly, as shown, the distal translating ramp 34 at
the distal end of the device fully supports the distal drive shaft
component 52 and the proximal drive shaft component 51 is pinned to
the frame 60 using pins 53. The pins 53 press through the groove
53A in the proximal drive shaft component 51 and are secured in
holes 63 passing into the frame 60.
[0068] A third alternative embodiment device 10B is illustrated in
FIG. 16. This third embodiment 10B has the same elements as the
first two embodiments 10, 10A with the exception that only one base
plate 20 is provided. In this embodiment 10B, there is only a frame
60. The frame 60 extends between a distal end 62 and a proximal end
61. Attached to the frame 60 is a fixation end plate 41 similar to
the fixation end plate 41 attached to the base plate 40. This
fixation end plate 41 is configured similar to the fixation end
plate 21 of the base plate 20. In this embodiment 10B, the
translating ramps 34, 35 only require the upper surface feature and
the pivoting hinged ramps 31 of the upper part of the device. In
such a case, the base plate 20 will move relative to the frame 60
as in the previous devices, but there is no underlying base plate
to move relative to the frame 60 as there is a single base plate.
The frame 60 provides the support for a lower adjacent vertebrae
and the base plate 20 is used to elevate the upper adjacent
vertebrae.
[0069] The device 10 generally is shown inserted within a spine 20
between adjacent vertebrae 2, 4 as illustrated in FIG. 17. The
interbody device 10 or 10A is inserted into the intervertebral body
disc space in the collapsed state with the base plates parallel to
one another so that the tangent planes of the base plates'
contoured surfaces are parallel. Another embodiment of the
interbody cage is where in the collapsed state the tangent planes
of the base plates' contoured surfaces intersect creating a
lordotic angle of various values. The expansion/contraction of the
anterior side of the interbody is controlled by rotation of the
drive shaft screw. As the drive shaft rotates, the ramp assemblies
will articulate the base plates by expanding the anterior side of
the base plates away from one another by translating the expanding
ramps away from the center of the interbody and pivoting the hinged
ramps. This operation distracts the spine vertebrae and adjusts the
alignment of the spinal column. The drive shaft has built in stops
using a shoulder to restrict movement of the expanding ramps
towards the center of the interbody once the interbody has fully
collapsed. The device is self-locking at any state allowing
complete freedom for anterior height/angle adjustment. The fixation
end plates incorporated into the base plates accept screws to
fixate the interbody device to the superior and interior spine
vertebrae. The locking tabs on the fixation end plates are rotated
to introduce a flat surface over the top of the screw holes to
prevent the screws from being removed from the fixation end plates
and vertebral bodies.
[0070] Variations in the present invention are possible in light of
the description of it provided herein. While certain representative
embodiments and details have been shown for the purpose of
illustrating the subject invention, it will be apparent to those
skilled in this art that various changes and modifications can be
made therein without departing from the scope of the subject
invention. It is, therefore, to be understood that changes can be
made in the particular embodiments described, which will be within
the full intended scope of the invention as defined by the
following appended claims.
* * * * *