U.S. patent application number 11/852379 was filed with the patent office on 2007-12-27 for apparatus and method for connecting spinal vertebras.
This patent application is currently assigned to SPINEFRONTIER LLS. Invention is credited to KINGSLEY R. CHIN.
Application Number | 20070299446 11/852379 |
Document ID | / |
Family ID | 38874436 |
Filed Date | 2007-12-27 |
United States Patent
Application |
20070299446 |
Kind Code |
A1 |
CHIN; KINGSLEY R. |
December 27, 2007 |
APPARATUS AND METHOD FOR CONNECTING SPINAL VERTEBRAS
Abstract
An orthopedic implantable device articulately connecting a first
spinal vertebra to an adjacent second spinal vertebra includes a
pair of first components adapted to be attached to locations left
and right of a midline of the first vertebra, respectively and a
pair of second components adapted to be attached to locations left
and right of a midline of the second vertebra, respectively. Each
of the first components includes a body and a male articulation
member attached to the first component body and each of the second
components includes a body and a female articulation member
attached to the second component body. The first components are
articulately connected to the second components by engaging the
male articulation members to the female articulation members,
thereby articulately connecting the first vertebra to said second
vertebra along lines left and right of the midlines and without
crossing the midlines, respectively.
Inventors: |
CHIN; KINGSLEY R.;
(PHILADELPHIA, PA) |
Correspondence
Address: |
AKC PATENTS
215 GROVE ST.
NEWTON
MA
02466
US
|
Assignee: |
SPINEFRONTIER LLS
PHILADELPHIA
PA
|
Family ID: |
38874436 |
Appl. No.: |
11/852379 |
Filed: |
September 10, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10669927 |
Sep 24, 2003 |
7282064 |
|
|
11852379 |
Sep 10, 2007 |
|
|
|
Current U.S.
Class: |
606/276 |
Current CPC
Class: |
A61B 2017/00004
20130101; A61F 2310/00359 20130101; A61F 2/28 20130101; A61B
17/00234 20130101; A61F 2/4405 20130101; A61B 17/7025 20130101;
A61B 17/7071 20130101; A61F 2002/30062 20130101; A61F 2310/00071
20130101; A61B 90/39 20160201; A61B 17/7007 20130101; A61B 17/7059
20130101; A61F 2310/00179 20130101; A61F 2310/00023 20130101; A61F
2210/0004 20130101; A61B 17/7062 20130101; A61B 17/7064 20130101;
A61F 2310/00017 20130101 |
Class at
Publication: |
606/061 ;
606/073 |
International
Class: |
A61B 17/58 20060101
A61B017/58 |
Claims
1. An orthopedic implantable device articulately connecting a first
spinal vertebra to an adjacent second spinal vertebra comprising: a
pair of first components adapted to be attached to locations left
and right of a midline of said first vertebra and without crossing
said first vertebra midline, respectively; a pair of second
components adapted to be attached to locations left and right of a
midline of said second vertebra and without crossing said second
vertebra midline, respectively; wherein said pair of first
components engages and articulately connects to said pair of second
components without crossing said first and second vertebra
midlines, respectively; and wherein each of said first components
comprises a body and a male articulation member attached to said
first component body and each of said second components comprises a
body and a female articulation member attached to said second
component body and wherein said first components are articulately
connected to said second components by engaging said male
articulation members to said female articulation members, thereby
articulately connecting said first vertebra to said second vertebra
along lines left and right of said midlines and without crossing
said first and second vertebra midlines, respectively.
2. The orthopedic implantable device of claim 1 wherein said male
articulation member comprises a hook and said female articulation
member comprises a loop.
3. The orthopedic implantable device of claim 1 wherein each of
said first component bodies further comprises a female articulation
member.
4. The orthopedic implantable device of claim 1 wherein each of
said second component bodies further comprises a male articulation
member.
5. The orthopedic implantable device of claim 1 wherein said
locations of said first and second vertebrae comprise one of a
pedicle, transverse processes, facets, pars interarticularis,
intervertebral disc, lamina, or vertebral body.
6. The orthopedic implantable device of claim 1 wherein said bodies
of said pair of first components are attached to first and second
pedicles of said first vertebra, respectively, and said bodies of
said pair of second components are attached to first and second
pedicles of said second vertebra, respectively.
7. The orthopedic implantable device of claim 6 wherein said pairs
of first and second components are attached to said first and
second vertebrae, respectively, via at least one of screws, wires,
or hooks.
8. The orthopedic implantable device of claim 1 wherein said pair
of first components are articulately connected to said pair of
second component s via a hinge.
9. The orthopedic implantable device of claim 1 wherein said pairs
of first and second components have adjustable length.
10. The orthopedic implantable device of claim 9 wherein said
length of said first and second components can be adjusted between
10 and 200 millimeters.
11. The orthopedic implantable device of claim 1 wherein said
female articulation members are formed within said second component
bodies and comprise a bar connecting opposite sides of a cavity
formed within a surface of the body.
12. The orthopedic implantable device of claim 1 comprising at
least one of metal, plastic, ceramic, bone, polymers, composites,
absorbable material, biodegradable material, or combinations
thereof.
13. The orthopedic implantable device of claim 1 wherein said first
and second vertebrae comprise one of cervical, thoracic, lumbar or
sacrum vertebrae.
14. A spine stabilization method articulately connecting a first
vertebra to a second vertebra comprising: providing a pair of first
components wherein each of said first components comprises a body
and a male articulation member attached to said first component
body; attaching said pair of first components to locations left and
right of a midline of said first vertebra, respectively; providing
a pair of second components wherein each of said second components
comprises a body and a female articulation member attached to said
second component body; attaching said pair of second components to
locations left and right of a midline of said second vertebra,
respectively; and engaging said male articulation members of said
first components to said female articulation members of said second
components and thereby articulately connecting said pair of first
component to said pair of second components without crossing said
first and second vertebra midlines, respectively.
Description
CROSS REFERENCE TO RELATED CO-PENDING APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/669,927 filed on Sep. 24, 2003 and entitled APPARATUS AND
METHOD FOR CONNECTING SPINAL VERTEBRAS the contents of which are
expressly incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an apparatus and a method
for connecting spinal vertebrae, and more particularly to an
apparatus and a method that connects spinal vertebrae while
preserving spinal stability and mobility.
BACKGROUND OF THE INVENTION
[0003] The human spine 29 comprises individual vertebrae 30 that
interlock with each other to form a spinal column, shown in FIG.
1A. Referring to FIGS. 1B, 1C, and 1D, each vertebra 30 has a
cylindrical bony body (vertebral body) 32, two pedicles 48
extending from the vertebral body 32, a lamina 47 extending from
the pedicles 48, three winglike projections (two transverse
processes 33, 35 extending from the pedicles 48 and one spinous
process 34 extending from the lamina 47), pars interarticularis 36,
two superior facets 46 extending from the pedicles 48 and two
inferior facets 45 extending from the lamina 47. The pars
interarticularis 36 connects the superior 46 and inferior 45 facets
on either side of the spinous process 34. The bodies of the
vertebrae 32 are stacked one on top of the other and form the
strong but flexible spinal column. The spinous process 34, lamina
47, pars interarticularis 36, superior facets 46, inferior facets
45, transverse processes 33, and pedicles 48 are positioned so that
the space they enclose forms a tube, i.e., the spinal canal 37. The
spinal canal 37 houses and protects the spinal cord and other
neural elements. A fluid filled protective membrane, the dura 38,
covers the contents of the spinal canal. The spinal column is
flexible enough to allow the body to twist and bend, but sturdy
enough to support and protect the spinal cord and the other neural
elements.
[0004] The vertebrae 30 are separated and cushioned by thin pads of
tough, resilient fiber known as inter-vertebral discs 40.
Inter-vertebral discs 40 provide flexibility to the spine and act
as shock absorbers during activity. There is a small opening
(foramen) 42 between each vertebra 30, through which nerves 44 pass
and go to different body parts. When the vertebrae are properly
aligned the nerves 44 pass through without a problem. However, when
the vertebrae are misaligned or a constriction 45 is formed in the
spinal canal, the nerves get compressed 44a and may cause back
pain, leg pain or other neurological disorders. Disorders of the
spine that may cause misalignment of the vertebrae or constriction
of the spinal canal include spinal injuries, infections, tumor
formation, herniation of the inter-vertebral discs (i.e., slippage
or protrusion), arthritic disorders, and scoliosis. In these
pathologic circumstances, surgery may be tried to either decompress
the neural elements and/or fuse adjacent vertebral segments.
Decompression may involve laminectomy, discectomy, or corpectomy.
Laminectomy involves the removal of part of the lamina 47, i.e.,
the bony roof of the spinal canal. Discectomy involves removal of
the inter-vertebral discs 40. Corpectomy involves removal of the
vertebral body 32 as well as the adjacent disc spaces 40.
Laminectomy and corpectomy result in central exposure of the dura
38 and its contents. An exposed dura 38 puts the neural elements
and spinal cord at risk from direct mechanical injury or scarring
from overlying soft tissues. Scarring is considered a major cause
for failed back syndrome in which patients continue to have back
and leg pain after spinal surgery. Current methods to decrease the
risk of developing this syndrome include covering the dura with fat
harvested from the patient's subcutaneous tissues or using a
synthetic material. However, no material as yet has been used that
completely or significantly prevents scarring of the dura and nerve
roots after spine surgery in humans.
[0005] Furthermore, laminectomy predisposes the patient to
instability through the facet joints and may lead to
post-laminectomy kyphosis (abnormal forward curvature of the
spine), pain, and neurological dysfunction. Therefore the surgeon
needs to stabilize the spine after laminectomy procedures and after
corpectomy. One spine stabilization method is fusion. Fusion
involves the fixation of two or more vertebrae. Fusion works well
because it stops pain due to movement of the intervertebral discs
40 or facets 45, 46, immobilizes the spine, and prevents
instability and or deformity of the spine after laminectomy or
corpectomy. However, spinal fusion limits spinal mobility.
Maintaining spinal mobility may be preferred over fusion in some
cases to allow more flexibility of the spine and to decrease the
risk of junction problems above and below the level of the fixation
due to increased stress.
[0006] An arthritic facet joint may also cause back pain. Since the
majority of the motion along the spine occurs at the facet joints,
fusing the diseased facet would often relieve pain but again at a
high cost of fusing across at least one spinal segment thus
preventing motion and effectively increasing stresses at the
adjacent facet joints. Increased stresses predispose facet joints
to accelerated arthritis, pain, and instability requiring
additional surgery to fuse these levels. This cyclic process
results in an overall decreased mobility of the spine. Therefore,
it is an attractive alternative to attempt to replace the diseased
facet without resorting to fusion, thus avoiding significant
limitation in mobility of the spine. The obvious solution would be
to replace the opposing surfaces of each facet to preserve motion
between the surfaces. However, any efforts to replace the facets at
their natural location necessitate destroying the facet capsule and
risks producing an unstable joint. Therefore, it is desirable to
achieve spine stabilization that preserves mobility, and does not
cause tissue scarring or destroy the facet capsule. It is also
desirable to be able to implant the stabilization device
percutaneously utilizing minimally invasive surgery.
SUMMARY OF THE INVENTION
[0007] In general, in one aspect, the invention features an
orthopedic implantable device articulately connecting a first
spinal vertebra to an adjacent second spinal vertebra. The
orthopedic implantable device includes a pair of first components
adapted to be attached to locations left and right of a midline of
the first vertebra without crossing the midline and a pair of
second components adapted to be attached to locations left and
right of a midline of second vertebra without crossing the midline.
The pair of first components engages and articulately connects to
the pair of second components without crossing the midlines,
respectively. Each of the first components comprises a body and a
male articulation member attached to the first component body and
each of the second components comprises a body and a female
articulation member attached to the second component body. The
first components are articulately connected to the second
components by engaging the male articulation members to the female
articulation members, thereby articulately connecting the first
vertebra to the second vertebra along lines left and right of the
mentioned midlines and without crossing the midlines,
respectively.
[0008] Implementations of this aspect of the invention may include
one or more of the following features. The male articulation member
may comprise a hook and the female articulation member may comprise
a loop. The first component body may further comprise at least one
female articulation member and the second component body may
further comprise at least one male articulation member. The
locations left and right of the midlines of the first and second
vertebrae may be a pedicle, transverse processes, facets, lamina,
pars interarticularis, or vertebral body. The body of the first
component may be attached to first and second pedicles of the first
vertebra and the body of the second component may be attached to
first and second pedicles of the second vertebra, respectively. The
first and second components may be attached to the first and second
vertebrae, respectively, via screws, wires, or hooks. The first
component may be articulately connected to the second component via
a hinge. The first and second components may have adjustable length
and the length may be adjusted between 10 and 200 millimeters. The
first and second components may be made of metal, plastic, ceramic,
bone, polymers, composites, absorbable material, biodegradable
material, and combinations thereof. The female articulation members
may be formed within the second component bodies. The male
articulation member may be a hook and the female articulation
member may be a bar connecting opposite sides of a cavity formed
within a bottom surface of the body.
[0009] In general, in another aspect, the invention features a
spine stabilization method articulately connecting a first vertebra
to a second vertebra including the following steps. First providing
a pair of first components and attaching the first components to
locations left and right of the midline of the first vertebra,
respectively. Each first component comprises a body and a male
articulation member attached to the body. Next, providing a pair of
second components and attaching the second components to locations
left and right of the midline of the second vertebra, respectively.
Each second component comprises a body and a female articulation
member. Finally, engaging the male articulation members to the
female articulation members and thereby articulately connecting the
first component to the second component without crossing the
midlines, respectively.
[0010] Among the advantages of this invention may be one or more of
the following. The implantable spinal stabilization device
stabilizes the spine, while allowing the patient to retain spinal
flexibility by preserving motion between adjacent vertebras. This
spinal stabilization device may be implanted percutaneously along
the sides left and right of the spine utilizing minimally invasive
surgery, i.e., without the need to make a large midline incision
and stripping the erector spinae muscles laterally. There is also
no need to remove the posterior elements of the veretebrae such as
the spinous processes and lamina because the components do not
cross the vertebral midlines. The spinal stabilization device may
be used for the treatment of a multitude of spinal disorders
including facet arthritis and spinal stenosis. The implantable
device has a compact structure and low profile. The articulation
mechanism includes male and female articulation members attached to
the corresponding first and second components and provides a true
constrained articulation between the first and second components by
engaging the male articulation member with the female articulation
member. This constrained articulation mechanism prevents accidental
separation and slippage of the connected vertebrae during
motion.
[0011] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and description below. Other
features, objects and advantages of the invention will be apparent
from the following description of the preferred embodiments, the
drawings and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Referring to the figures, wherein like numerals represent
like parts throughout the several views:
[0013] FIG. 1A is a side view of the human spinal column;
[0014] FIG. 1B is an enlarged view of area A of FIG. 1A;
[0015] FIG. 1C is an axial cross-sectional view of a lumbar
vertebra;
[0016] FIG. 1D is a perspective view of a lumbar vertebra;
[0017] FIG. 2 is a schematic posterior view of an implantable spine
stabilization device according to this invention;
[0018] FIG. 3 is a posterior view of a spine stabilization
component of the implantable spine stabilization device of FIG.
2;
[0019] FIG. 4 is a perspective view of a lumbar vertebra with
resected spinous process, lamina, and facet joints and the
stabilization component of FIG. 3 attached to its pedicles;
[0020] FIG. 4A is a cross-sectional view of FIG. 3 along AA'
plane;
[0021] FIG. 5 is a perspective view of the spine stabilization
component of FIG. 3;
[0022] FIG. 5A is a cross-sectional view of FIG. 3 along BB'
plane;
[0023] FIG. 6 is a cross-sectional side view of the spine
stabilization device of FIG. 2 along midline 102;
[0024] FIG. 7 is a posterior view of a spine stabilization
component without a tail segment;
[0025] FIG. 8 is a flow diagram depicting the method of applying
the implantable spine stabilization device of this invention;
and
[0026] FIG. 9 is a schematic posterior view of another embodiment
of an implantable spine stabilization device according to this
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Referring to FIG. 2, an implantable spine stabilization
device 100 connects vertebra 92 to adjacent vertebra 94 and
vertebra 94 to adjacent vertebra 96. The spine stabilization device
100 includes modular components 110, 120 and 130. Modular
components 110, 120 and 130 have circular ends 110a and 110b, 120a
and 120b, 130a and 130b, respectively, that attach to pedicles 92A,
92B, 94A, 94B, 96A, and 96B of vertebra 92, 94 and 96,
respectively, via pedicle screws 111a, 111b, 121a, 121b, 131a, and
131b, respectively. Modular components 110, 120 and 130 replace the
resected laminas, pars interarticularis, facets and spinous
processes of the vertebra 92, 94, and 96, respectively. Modular
component 110 is articulately connected to component 120 along the
midline 102 of the device 100 and the corresponding vertebrae 92
and 94, shown in FIG. 6. Similarly modular component 120 is
articulately connected to component 130. Additional modular
components may be added to extend the spine stabilization device
100 in either caudad 272 or cephalad 270 directions. The modular
structure of the spine stabilization device 100 allows a surgeon to
replace laminas, facets, pars interarticularis, and spinous
processes over any distance and orientation along the entire spine
29.
[0028] Referring to FIG. 3, modular component 110 comprises a
lamina 114, two circular ends 110a, 110b extending laterally from
opposite sides of the lamina 114, a tail segment 118 extending from
the lower portion of the lamina 114, and a spinous process 116
protruding posteriorly from the top surface of the lamina 114. The
lamina 114 has a width 81 and a length 82 that depend upon the
distance between the pedicles 92A and 92B and the length of the
vertebra 92, respectively. The length 83 of the tail segment 118
depends upon the intervertebral distances. In one example, the
width 81 is in the range between 20 millimeters and 80 millimeters,
length 82 is in the range of 10 millimeters and 80 millimeters,
length 83 is in the range of 4 millimeters and 60 millimeters and
height 84 is in the range of 4 millimeters and 30 millimeters.
Width 81, length 82, length 83 and height 84 have different values
for the different type of vertebrae, including lumbar, thoracic,
sacral and cervical.
[0029] Referring to FIG. 3 and FIG. 5, pedicle screw 111b comprises
a body portion 140, a first head portion 142, a second head portion
144, and a head 146. The body portion 140 of the pedicle screw 111b
has helical threads on its exterior surface and screws into the
vertebral body 32 through the pedicle 92B. A hexagonal screwdriver
(not shown) is inserted into a slot 148 formed on the head 146 of
the pedicle screw 111b and is used to drive the screw 111b into the
vertebral body 32. The first head portion 142 is directly above the
body portion 140 and has a smooth or serrated outer surface 143 for
receiving the circular end 110b of modular component 110. End 10b
has an aperture 152b that allows end 110b to slide over the pedicle
screw 111b. The second head portion 144 has a threaded outer
surface for receiving locking nut 112b. Locking nut 112b slides
over the head 146 of the pedicle screw 111b and screws around the
threaded outer surface of the second head portion 144, thus
securely attaching the circular end 110b to pedicle screw 111b. In
one example, pedicle screw 111a has a length 220 of 57 millimeters
and a diameter 222 of 6.5 millimeters.
[0030] Referring to FIG. 4 and FIG. 4A, the cross-section of lamina
114 along AA' has a U-shape and the roof 114c of the lamina (top of
U-shape) is elevated above the spinal canal 37. The sides 114a and
114b of the lamina 114 run first at a gentle slope downwards about
5 degrees and then drop more sharply at about 80 degrees to get to
the pedicles 92A and 92B, respectively. The U-shape form of the
lamina 114 provides space between the spine stabilization device
100 and the spinal canal 37 and is also designed to clear the
facets 46 laterally, in case they were not previously resected.
This arrangement covers the central spinal canal and protects the
neural elements from scar tissue formation or mechanical damage.
The lamina 114 has a flared lower portion that extends into the
tail segment 118.
[0031] In the embodiment of FIG. 4A the width 81 of the lamina 114
is extended or contracted via mechanism 90. In this embodiment the
lamina 114 comprises a first segment 92 and a second segment 94.
Segment 94 is allowed to slide in the lateral direction 86 and can
rotate around the axis 87. The lateral motion of segment 94 allows
the adaptation of the modular component 110 to vertebrae with
various pedicle distances. The rotation of segment 94 around the
axis 87 allows accurate positioning of the circular end 110b over
the pedicle screw 111b and accommodates pedicles that are not
perfectly aligned in the cephalo-caudad direction. Segments 94 and
92 have overlapping elongated slots 184A and 184B, respectively,
extending through the thickness of the corresponding segment. A
housing 182 slides over the overlapping segments 92 and 94. Housing
182 has an elongated slot 186 that runs through the thickness of
the housing 182 and is aligned with the elongated slots 184A and
184B. The position of the overlapping segments 92 and 94 and the
housing 182 is secured via a screw 188 that is threaded through the
elongated slots 184A, 184B, and 186. In one example, the width 81
of the lamina 114 is 40 millimeters and it can be increased or
decreased up to 8 millimeters via the two sliding mechanisms 90.
Circular ends 110a, 110b have apertures 152a, 152b, respectively.
Apertures 152a and 152b have serrated inner surfaces for receiving
a pedicle screw with matching longitudinal serrations 143, shown in
FIG. 5. The top and/or bottom surfaces of circular ends 110a, 110b
have radial extending grooves 88 that match the grooves 89 of the
locking nuts 112a, 112b.
[0032] Referring to FIG. 5 and FIG. 5A, the posteriorly protruding
spinous process 116 includes a cavity 115 formed in the bottom
surface of the lamina 114 within the spinous process 116. Inside
the cavity 115 there is a horizontally extending bar 117 attached
to opposite cavity walls 115a, 115b. Referring to FIG. 6, the end
of the tail segment 118 of modular component 110 forms a hook 119.
Hook 119 engages around the horizontal bar 117 of the adjacent
modular component 120 and forms an articulated connection between
the two modular components 110 and 120. The cavity 115 is contoured
to allow smooth gliding of the outer surface 118a of the tail
segment 118 around the horizontal bar 117.
[0033] Referring to FIG. 7, a modular component 140 without the
tail segment 118 is implanted to the pedicles on the vertebra that
is below but adjacent to the lowest (in the caudad direction 272)
level that underwent either a laminectomy or facetectomy. This
vertebra will still have its natural spinous process and
ligamentous attachment to the next lower vertebra. This vertebral
level will therefore provide stability to the end of the
stabilization assembly 100 since this vertebral level will have
preserved facets and ligamentous attachments.
[0034] Referring to FIG. 8, a method 400 of using the spine
stabilization device 100 comprises the following steps. Opening an
incision in the patient's back, and exposing first and second
vertebrae, the vertebra that is immediately above but adjacent to
the first vertebra (cephalad direction), and the vertebra that is
immediately below but adjacent to the second vertebra (caudad
direction) (405). Performing laminectomy and/or facetectomy
posteriorly of the first and second vertebrae (410). Placing
pedicle screws within the pedicles of the first and second
vertebra, the vertebra immediately above the first vertebra, and
the vertebra immediately below the second vertebra (420). Engaging
a first modular component to a second modular component. In one
example, the modular components are as shown in FIG. 3. Placing the
apertures of the two circular ends 110a, 110b of the first modular
component over the two contralateral pedicle screws on the first
vertebra, and adjusting the length and orientation of the two end
segments 94 of the lamina (430). Placing the apertures of the two
circular ends 110a, 110b, of the second modular component over the
two contralateral pedicle screws on the second vertebra, and
adjusting the length and orientation of the two end segments 94 of
the lamina (440). Engaging a third modular component without a tail
segment, as shown in FIG. 7, to the tail of the second modular
component, placing the apertures of the two circular ends 110a,
11ab, of the third modular component over two contralateral pedicle
screws on the vertebra that is immediately below the second
vertebra, and adjusting the length and orientation of the two end
segments 94 of the lamina (450). Engaging a fourth modular
component to the first modular component, placing the apertures of
the two circular ends 110a, 110b, of this fourth modular component
over the two contralateral pedicle screws on the vertebra that is
immediately above the first vertebra, and adjusting the length and
orientation of the two end segments 94 of the lamina (455).
Tightening of the nuts over the pedicle screws down on the circular
ends (460) and closing of the incision in the patient's back
(470).
[0035] Referring to FIG. 9, an implantable spine stabilization
device 200 connects vertebra 92 to adjacent vertebra 94. The spine
stabilization device 200 includes modular components 210, 220, 230
and 240. Modular components 210, 220, 230 and 240 have circular
ends 211, 221, 231 and 241, respectively, that attach to pedicles
92B, 94B, 92A, 94A, of vertebrae 92 and 94, respectively, via
pedicle screws 212, 222, 232, and 242 respectively. Modular
component 210 is articulately connected to component 220 along a
line 201 left of the midline 202 of vertebrae 92 and 94. Modular
component 230 is articulately connected to component 240 along a
line 203 right of the midline 202 of vertebrae 92 and 94.
Additional modular components may be added left and/or right of the
midline 202 to extend the spine stabilization device 200 in either
caudad 272 or cephalad 270 directions. Modular components 210 and
230 are articulately connected to modular components 220 and 240,
respectively with an articulation mechanism similar to the one of
FIG. 2, and FIG. 6. Modular components 210, 230 have hook tail
segments 119 similar to the one described in FIG. 6. Modular
components 220 and 240 have a cavity 115 with a bar 117 extending
across opposite cavity walls, thereby forming a loop similar to the
one described in FIG. 5 and FIG. 5A. Hook-shaped tail segment 119
engages around bar 117 into the loop formed in cavity 115, thereby
articulately connecting modular component 210 and 230 to modular
components 220 and 240, respectively. Modular components 210, 220,
230 and 240 may have adjustable length. The length of the modular
components may be adjusted to be in the range of 10 millimeters to
200 millimeters.
[0036] Other embodiments are within the scope of the following
claims. For example, the articulation mechanism between the modular
components may be a hinge. There may be more than one articulation
mechanisms medial or lateral to the medial line 102 on a given
vertebra, and/or medial to both the natural facet joints. The ends
of the modular components may be secured to pedicle screws via
connectors. The ends of the modular components may be attached to
the vertebrae via hooks. Other locations where screws, wires, or
hooks may be anchored for attaching the stabilization device of
this invention include the transverse processes 33, 35, the
vertebral body 32, and the lamina 47. The modular components may be
solid without adjustable ends. Modular components 110,120,130 and
140 may be manufactured from a variety of materials including among
others stainless steel, titanium, nickel, composites, ceramics,
plastic, bone, bioabsorbable material or combination thereof.
Pedicle screws may be manufactured from a variety of materials
including among others stainless steel, titanium, gold, silver
ceramics, plastic, bioabsorbable material, or alloys thereof.
[0037] Several embodiments of the present invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *