U.S. patent application number 16/242446 was filed with the patent office on 2019-09-12 for growing spine model.
The applicant listed for this patent is K2M, Inc.. Invention is credited to Michael Barrus, Clint Boyd, Larry McClintock, Brandon Moore.
Application Number | 20190279532 16/242446 |
Document ID | / |
Family ID | 53716330 |
Filed Date | 2019-09-12 |
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United States Patent
Application |
20190279532 |
Kind Code |
A1 |
McClintock; Larry ; et
al. |
September 12, 2019 |
Growing Spine Model
Abstract
A spinal surgery modeling system includes a spine model and a
spine movement device. The spinal surgery modeling system provides
a three-dimensional hands-on model that can be configured to have
any desired variation of spinal alignment of the spine model by
hydraulic actuation of the spine movement device to simulate the
biomechanical feel and behavior of a patient's spine. The spine
model may include various vertebral body or disc conditions and
allows a clinician to examine and/or adjust the model and observe
the three-dimensional outcome of such adjustments.
Inventors: |
McClintock; Larry; (Gore,
VA) ; Moore; Brandon; (Minneapolis, MN) ;
Boyd; Clint; (Winchester, VA) ; Barrus; Michael;
(Redondo Beach, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
K2M, Inc. |
Leesburg |
VA |
US |
|
|
Family ID: |
53716330 |
Appl. No.: |
16/242446 |
Filed: |
January 8, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14798591 |
Jul 14, 2015 |
10198970 |
|
|
16242446 |
|
|
|
|
62024127 |
Jul 14, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G09B 23/32 20130101;
G09B 23/30 20130101; G09B 23/00 20130101; G09B 23/34 20130101 |
International
Class: |
G09B 23/32 20060101
G09B023/32; G09B 23/34 20060101 G09B023/34 |
Claims
1. A spinal construct comprising: a plurality of screws; and an
adjustable rod including: a hollow member defining a bore
therethrough; and a first end member including a first segment in
direct slidable engagement with the bore of the hollow member and a
second segment securable to at least one screw of the plurality of
screws, the first segment having a first shape and the second
segment having a second shape different from the first shape, and
the bore of the hollow member having a complementary geometry to
that of the first segment.
2. The spinal construct according to claim 1, wherein the first
segment of the first end member is rotationally fixed relative to
the hollow member.
3. The spinal construct according to claim 1, wherein the first
shape of the first segment of the first end member is an I-beam
shape.
4. The spinal construct according to claim 1, wherein the second
shape of the second segment of the first end member is a compound
shape.
5. The spinal construct according to claim 4, wherein the compound
shape includes an elongate round portion, an elongate head portion,
and a neck portion connecting the elongate round portion with the
elongate head portion.
6. The spinal construct according to claim 3, wherein the bore of
the hollow member has an I-beam shape.
7. The spinal construct according to claim 1, wherein the hollow
member has a fixed axial length and the bore extends longitudinally
through the fixed axial length, and the bore is open at the first
and second ends of the hollow member.
8. The spinal construct according to claim 1, wherein the first end
member is freely extendable and retractable relative to the hollow
member.
9. The spinal construct according to claim 1, wherein the
adjustable rod further includes a second end member including a
third segment engageable with the bore of the hollow member and a
fourth segment securable to at least one screw of the plurality of
screws.
10. The spinal construct according to claim 9, wherein the third
segment of the second end member has a third shape different from a
fourth shape of the fourth segment of the second end member.
11. The spinal construct according to claim 9, wherein the first
and second end members are axially movable relative to the hollow
member.
12. The spinal construct according to claim 11, wherein the first
and second end members are freely extendable and retractable
relative to the hollow member.
13. The spinal construct according to claim 9, wherein the second
end member has a different range of travel relative to the hollow
member than the first end member.
14. The spinal construct according to claim 9, wherein the third
segment of the second end member has a third shape that is
different from the first shape of the first segment of the first
end member.
15. The spinal construct according to claim 14, wherein the first
segment of the first end member and the third segment of the second
end member are each in direct slidable engagement with the bore of
the hollow member.
16. A spinal construct comprising: a plurality of screws; and an
adjustable rod including: a hollow member defining a bore
therethrough; and a first end member including a first segment in
direct slidable engagement with the bore of the hollow member and a
second segment securable to at least one screw of the plurality of
screws, the first segment having an I-beam shape and the second
segment having a compound shape including an elongate round
portion, an elongate head portion, and a neck portion connecting
the elongate round portion with the elongate head portion, wherein
the bore of the hollow member has an I-beam shape.
17. The spinal construct of claim 16, wherein the adjustable rod
further includes a second end member including a third segment
engageable with the bore of the hollow member and a fourth segment
securable to at least one screw of the plurality of screws.
18. The spinal construct of claim 17, wherein the first and second
end members are axially movable relative to the hollow member.
19. The spinal construct of claim 16, wherein the first segment of
the first end member is rotationally fixed relative to the hollow
member.
20. The spinal construct of claim 16, wherein the second end member
has a different range of travel relative to the hollow member than
the first end member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This present application is a continuation of U.S. patent
application Ser. No. 14/798,591, filed Jul. 14, 2015, which claims
the benefit of, and priority to, U.S. Provisional Patent
Application Ser. No. 62/024,127, which was filed on Jul. 14, 2014,
the entire contents of which are hereby incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present disclosure relates to orthopedic surgical
devices for stabilizing and fixing the bones and joints of a body.
Particularly, the present disclosure relates to a growing spine
model that simulates the effects of expanding vertebral bodies
apart and the three dimensional impact on a spinal column.
BACKGROUND
[0003] The spinal column is a complex system of bones and
connective tissues that provide support for the human body and
protection for the spinal cord and nerves. The human spine is
comprised of thirty-three vertebrae at birth and twenty-four as a
mature adult. Between each pair of vertebrae is an intervertebral
disc, which maintains the space between adjacent vertebrae and acts
as a cushion under compressive, bending, and rotational loads and
motions.
[0004] There are various disorders, diseases, and types of injury
that the spinal column may experience in a lifetime. The problems
may include, but are not limited to, scoliosis, kyphosis, excessive
lordosis, spondylolisthesis, slipped or ruptured disc, degenerative
disc disease, vertebral body fracture, and tumors. Persons
suffering from any of the above conditions typically experience
extreme and/or debilitating pain, and often times diminished nerve
function.
[0005] Conventionally, orthopedic surgeons receive training in the
use of orthopedic devices and the performance of surgical methods
to correct vertebral column injuries and diseases by the
application of methods and devices on cadavers. The amount of
training for each surgeon is limited by the expense, availability,
scheduling, and other logistic requirements associated with the use
of cadavers.
[0006] Further, spine surgeons, when planning for a surgical
procedure on a specific patient, are normally limited to a study of
two-dimensional radiographic data and a complete lack of hands-on
manipulation rehearsal of a method prior to operating on a patient.
In recent years there has been a growing number of orthopedic
practices and hospitals that have made the transition from film to
all digital environments. Software based tools for orthopedic image
review, analysis, and preoperative planning are becoming
conventional tools of the orthopedic surgeon. While advances in
surgical planning have been made, they are simply limited to
improvements in providing two-dimensional data for study and
planning. To receive hands-on training or to rehearse a surgical
method, a surgeon is still limited to the use of cadavers.
[0007] With such training and rehearsal limitations, it is not
uncommon during an actual surgical procedure for a surgeon to
encounter unforeseen anatomical or biomechanical conditions that
may require an immediate revision of the surgical plan as it
proceeds. The need to provide more, less expensive ways to train
surgeons or to permit hands-on surgery planning and rehearsal in
the use of spinal surgery methods and devices is particularly
needed in the treatment of spine conditions, such as scoliosis. It
is not uncommon in the surgical treatment of scoliosis that
forceful manipulation and realignment of the spinal column can be a
long, complicated mechanical effort that often includes a serious
threat of damage to the spinal cord.
[0008] Further, the biomechanical behavior and particularly soft
tissue forces on the spinal column when applying methods and
devices to a cadaver are far different from that which are normally
experienced in a surgical procedure on a living patient.
[0009] Thus, a need exists for a three-dimensional hands-on spinal
surgery modeling system that can be used by surgeons for training
in the use of devices and methods, and that can also be used in the
planning and manual rehearsal of surgical procedures for
patients.
SUMMARY
[0010] The present disclosure is directed to a three-dimensional
modeling system for hands-on training and/or surgical rehearsal of
surgical methods, devices, and instruments that provides a
clinician with an anatomically and biomechanically realistic model
of a spine in a non-surgical environment. The system includes a
spine movement device that interacts with a spine model so as to
configure the spine in a desired alignment, with selected degrees
of force vectors biasing the spine in selected positions to provide
a modeling system that can be used as a surgeon training device or
as a spinal surgery rehearsal platform.
[0011] The spine movement device of the system of the present
disclosure may be used with any of a variety of spine models that
can be selected by size and conformation to simulate, for example,
pediatric, adult, and geriatric spinal columns.
[0012] The system can be prepared to simulate the anatomy and
biomechanics of a patient such that a three-dimensional hands-on
surgery rehearsal platform is provided.
[0013] The system of the present disclosure is useful for
simulating common deformities such as scoliosis, kyphosis, sagittal
imbalance, and other spinal abnormalities. In addition to the
training benefits provided by the system, manual rehearsal of
planned methods in the treatment of spinal deformities and
conditions may provide a faster, more effective, and safer surgical
correction for a patient.
[0014] The system of the present disclosure can simulate a spine as
it is growing, simulating the growth of vertebral bodies and
discs.
[0015] In accordance with an aspect of the present disclosure, a
spinal surgery modeling system includes a spine model including
vertebral bodies defining disc spaces between adjacent vertebral
bodies, and a spine movement device. The spine movement device
includes a plurality of cylinders, a plurality of pistons, and a
plurality of inflation members. Each cylinder of the plurality of
cylinders includes an elongate body defining a bore, and an inlet
and an outlet. Each piston of the plurality of pistons includes an
elongate body having a proximal end and a distal end, and the
distal end of each piston extends into the inlet and frictionally
engages the bore of one cylinder of the plurality of cylinders.
Each inflation member of the plurality of inflation members is
disposed within one of the disc spaces of the spine model and is
fluidly coupled to the outlet of one cylinder of the plurality of
cylinders. The plurality of pistons are movable with respect to the
plurality of cylinders to hydraulically inflate or deflate the
plurality of inflation members.
[0016] The spine movement device may further includes a plurality
of tubes. Each tube of the plurality of tubes may fluidly connect
the outlet of one cylinder of the plurality of cylinders with one
inflation member of the plurality of inflation members.
[0017] The spine movement device may further include a back plate
having plurality of openings extending therethrough, wherein each
cylinder of the plurality of cylinders is positioned through one
opening of the plurality of openings. In embodiments, the spine
movement device further includes a front plate positioned in spaced
relation relative to the back plate, and the proximal ends of the
plurality of pistons are secured to the front plate. In some
embodiments, the front plate includes a plurality of recesses
aligned with the plurality of openings of the back plate and
mechanically engaged with the proximal ends of the plurality of
pistons to lock the plurality of pistons to the front plate.
[0018] The spine movement device may further include a linear
actuating member having an elongated body extending through the
front and back plates for moving the plurality of pistons
proximally and distally with respect to the plurality of cylinders.
In embodiments, the elongated body of the linear actuating member
extends through central apertures defined in each of the front and
back plates, and each opening of the plurality of openings of the
front and back plates are disposed around the respective central
aperture. In some embodiments, the central aperture of the back
plate is a threaded aperture that engages a threaded portion of the
linear actuating member. In certain embodiments, the spine movement
device further includes a rotatable handle secured to a proximal
end of the linear actuating member.
[0019] In embodiments, the spine movement device further includes
an intermediate plate having plurality of opening extending
therethrough that are aligned with the plurality of openings of the
back plate, wherein the proximal end of each cylinder of the
plurality of cylinders includes a catch positioned between the
intermediate plate and the back plate.
[0020] The spinal surgery modeling system may further include at
least one spinal construct attached to the spine model. In
embodiments, the at least one spinal construct includes a plurality
of screws and an adjustable rod. The adjustable rod may include a
center member and first and second end members. Each of the first
and second end members may include a first segment slidably
engagable with an interior surface of the center member, and a
second segment including a connecting portion securable to at least
one of the plurality of screws. In some embodiments, the first
segment of each of the first and second end members has an I-beam
shape and the second segment of each of the first and second end
members has a compound shape including an elongate round portion,
an elongate head portion, and a neck portion connecting the
elongate round portion with the elongate head portion.
[0021] In accordance with another aspect of the present disclosure,
a method of simulating a spine includes: positioning an inflation
member within a disc space between vertebral bodies of a spine
model, the inflation member fluidly coupled to a cylinder of a
spine movement device, the spine movement device including a piston
having a distal end frictionally engaged with a bore of the
cylinder; and moving the piston distally within the bore of the
cylinder to displace a fluid disposed within the cylinder into the
inflation member to expand the inflation member and increase a
distance between the vertebral bodies.
[0022] In embodiments, moving the piston distally includes rotating
a handle secured to a linear actuating member of the spine movement
device to impart linear motion to the piston.
[0023] The method may further include moving the piston proximally
within the bore of the cylinder to draw the fluid into the bore of
the cylinder to deflate the inflation member and decrease the
distance between the vertebral bodies.
[0024] The method may further include implanting a spinal construct
in the spine model. In embodiments, implanting the spinal construct
includes securing an adjustable rod to the spine model with screws
such that moving the piston distally exerts a force on the screws
moving the screws away from each other and moving end members of
the adjustable rod relative to a center member of the adjustable
rod.
[0025] In accordance with yet another aspect of the present
disclosure, a method of using an adjustable rod includes:
implanting a first screw and a second screw in spaced relation
relative to each other in vertebral bodies of a spine; and securing
a first end member of an adjustable rod to the first screw and a
second end member of the adjustable rod in the second screw, the
first and second end members being in slidable engagement with a
center member extending between the first and second screws.
[0026] Other aspects, features, and advantages will be apparent
from the description, drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a front, perspective view of a spinal surgery
modeling system in accordance with an embodiment of the present
disclosure;
[0028] FIG. 2 is a back, perspective view of the spinal surgery
modeling system of FIG. 1;
[0029] FIG. 3 is a front, perspective view of a spine movement
device of the spinal surgery modeling system of FIG. 1;
[0030] FIG. 4 is a back, perspective view of the spine movement
device of FIG. 3;
[0031] FIG. 5 is an exploded view of the spine movement device of
FIG. 3;
[0032] FIG. 6A is a side view of the spine movement device of FIG.
3 in a first position;
[0033] FIG. 6B is a side view of the spine movement device of FIG.
3 in a second position;
[0034] FIG. 7A is a side view of the spinal surgery modeling system
of FIG. 1 in a first position;
[0035] FIG. 7B is an enlarged view of a portion of a spine model of
the spinal surgery modeling system, shown in the area of detail 7B
identified in FIG. 7A;
[0036] FIG. 8A is a front view of the spinal surgery modeling
system of FIG. 7A;
[0037] FIG. 8B is an enlarged view of a portion of a spine model of
the spinal surgery modeling system, shown in the area of detail 8B
identified in FIG. 8A;
[0038] FIG. 9A is a side view of the spinal surgery modeling system
of FIG. 1 in a second position;
[0039] FIG. 9B is an enlarged view of a portion of a spine model of
the spinal surgery modeling system, shown in the area of detail 9B
identified in FIG. 9A;
[0040] FIG. 10A is a front view of the spinal surgery modeling
system of FIG. 9A;
[0041] FIG. 10B is an enlarged view of a portion of a spine model
of the spinal surgery modeling system, shown in the area of detail
10B identified in FIG. 10A;
[0042] FIG. 11A is a front, perspective view of a spinal construct
of the spinal surgical modeling system of FIG. 1;
[0043] FIG. 11B is an exploded view of the spinal construct of FIG.
11A;
[0044] FIG. 12A is a side view of a central member of the spinal
construct of FIG. 11A;
[0045] FIG. 12B is a cross-sectional view of the central member of
FIG. 12A, taken along line 12B-12B of FIG. 12A;
[0046] FIG. 13A is a side view of an end member of the spinal
construct of FIG. 11A;
[0047] FIG. 13B is a cross-sectional view of the end member of FIG.
13A, taken along line 13B-13B of FIG. 13A;
[0048] FIG. 13C is a cross-sectional view of the end member of FIG.
13A, taken along line 13C-13C of FIG. 13A;
[0049] FIG. 14A is a front, perspective view of a spinal construct
for use with the spinal surgery modeling system of FIG. 1 in
accordance with another embodiment of the present disclosure;
[0050] FIG. 14B is an exploded view of the spinal construct of FIG.
14A;
[0051] FIG. 15A is a side view of a central member of the spinal
construct of FIG. 14A;
[0052] FIG. 15B is a cross-sectional view of the central member of
FIG. 15A, taken along line 15B-15B of FIG. 15A;
[0053] FIG. 16A is a perspective view of a polyaxial pedicle
screw;
[0054] FIG. 16B is an exploded, perspective view of the polyaxial
pedicle screw of FIG. 16A;
[0055] FIG. 16C is a perspective view of a set screw usable with
the polyaxial pedicle screw of FIGS. 16A and 16B;
[0056] FIG. 17A is an end view of a spinal construct including a
taper lock screw and an adjustable rod in accordance with another
embodiment of the present disclosure;
[0057] FIG. 17B is a partial cross-sectional view of a portion of
the taper lock screw of FIG. 17A shown in a partially locked
position; and
[0058] FIG. 17C is an end, cross-sectional view of the taper lock
screw of FIG. 17A in an unlocked position with the adjustable
rod.
[0059] Corresponding reference characters indicate corresponding
parts throughout the drawings.
DETAILED DESCRIPTION
[0060] Detailed embodiments of the present disclosure are disclosed
herein; however, it is understood that the following description
and each of the accompanying figures are provided as exemplary
embodiments of the present disclosure. Thus, the specific
structural and functional details provided in the following
description are non-limiting, and various modifications may be made
without departing from the spirit and scope of the present
disclosure.
[0061] In this disclosure, the term "clinician" refers to a doctor,
nurse, or other care provider and may include support personnel. As
used herein, the term "proximal" refers to the portion of a
structure closer to a clinician, while the term "distal" refers to
the portion of the same structure further from the clinician. The
term "cephalad" indicates a direction toward a patient's head,
whereas the term "caudad" indicates a direction toward a patient's
feet. The term "lateral" indicates a direction toward a side of the
body of a patient, i.e., away from the middle of the body of the
patient, whereas the term "medial" refers to a position toward the
middle of the body of a patient. The term "posterior" indicates a
direction toward a patient's back, and the term "anterior"
indicates a direction toward a patient's front. Additionally, in
the drawings and in the description that follows, terms such as
front, rear, upper, lower, top, bottom, and similar directional
terms are used simply for convenience of description and are not
intended to limit the disclosure.
[0062] As shown in FIGS. 1 and 2, a spinal surgery modeling system
10 includes a spine model 20, a spine movement device 30, and
optionally, one or more spinal constructs, such an adjustable rod
60 and screws 70. The spine model 20 and the spine movement device
30 may each be removably or fixedly attached to a base 12, and the
adjustable rod 60 and screw 70 may be affixed to the spine model
20. The spine model 20 may be a cadaveric or synthetic anatomically
and mechanically correct spine model of a pediatric, adult, or
geriatric spine which may exhibit any of a variety of spine
pathologies.
[0063] Turning now to FIGS. 3-6B, in conjunction with FIGS. 1 and
2, the spine movement device 30 includes a main frame 32 including
a back plate 34 having a proximal surface 34a, a distal surface
34b, a threaded central aperture 34c, and a plurality of openings
34d disposed around the central aperture 34c. Cylinders 36 are
positioned through the openings 34d of the back plate 34. Each
cylinder 36 includes an elongated body 36a defining a bore 36b
which may have a substantially consistent diameters along the
length thereof, a proximal end 36c including an inlet 36d and a
catch 36e that engages the proximal surface 34a of the back plate
34, and a distal end 36f including an outlet 36g. The outlets 36g
of each cylinder 36 is fluidly connected to a tube or tubing 38
that is fluidly connected to an inflation member 40, such as a
balloon.
[0064] An intermediate plate 42 includes a central aperture 42a and
a plurality of openings 42b disposed around the central aperture
42a that are sized and positioned to correspond with the openings
34d of the back plate 34. The intermediate plate 42 is placed
adjacent to the proximal surface 34a of the back plate 34, with
openings 42b aligned with openings 34d and the catch 36e of each
cylinder 36 positioned between the intermediate plate 42 and the
back plate 34. The intermediate plate 42 is secured to the back
plate 34 with fixation members 44, such as screws.
[0065] Pistons 46 include an elongated body 46a that may be the
length of the elongated body 36a of the cylinders 36, a proximal
end 46b that is secured to a front plate 48, and a distal end 46c
that is dimensioned to frictionally engage the bore 36b of the
cylinders 36. The front plate 48 includes a proximal surface 48a, a
distal surface 48b, and a central aperture 48c extending through
the proximal and distal surfaces 48a, 48b. The distal surface 48b
includes a plurality of recesses 48d that are aligned with the
openings 34d of the back plate 34 and mechanically engage and lock
the proximal end 46b of the pistons 46 thereto. The front plate 48
is positioned in spaced relation with respect to the back plate 34
with the distal ends 46c of the pistons 36 disposed within the bore
36b of the cylinders 36.
[0066] A linear actuating member 50, such as a threaded screw,
includes an elongated body 50a having a proximal end 50b and a
distal end 50c. The elongated body 50a of the linear actuating
member 50 is positioned through the central apertures 34c, 42a, and
48c of the back, intermediate, and front plates 34, 42, and 48,
respectively. A handle 52 is secured to the proximal end 50b of the
linear actuating member 50 and a nut 54 is disposed on the distal
end 50c of the linear actuating member 50 adjacent the distal
surface 34b of the back plate 34 to secure the components of the
device 30 together.
[0067] Rotation of the handle 52 rotates the linear actuating
member 50, which in turn imparts linear motion to the linear
actuating member 50 as linear actuating member 50 engages the
threaded central aperture 34c of the back plate 34. The linear
motion thereby causes the front plate 48 to move proximally or
distally with respect to the back plate 34, and in turn, causes the
pistons 46 to move proximally or distally within the bores 36b of
the cylinders 36. A fluid (not shown), such as a liquid or gas, is
disposed within the bores 36b of the cylinders 36 such that distal
movement of the pistons 46 displaces the fluid and hydraulically
inflates/expands the inflation members 40, and proximal movement of
the pistons 46 draws the fluid back into the bores 36b of the
cylinders 36, hydraulically deflating the inflation members 40. The
amount of fluid contained within each of the cylinders 36 may be
the same or different.
[0068] In an exemplary method of use, each inflation member 40 is
positioned within the disc space between each of the vertebral
bodies 22 of the spine model 20, as shown in FIGS. 7A-8B. A user
rotates the handle 52 of the spine movement device 30 to drive the
linear actuating member 50 distally thereby displacing fluid from
the cylinders 36 into the inflation members 40. As shown in FIGS.
9A-10B, expansion of the inflation members 40 increases the
distance between the vertebral bodies 22 simulating, for example,
growth of a spine.
[0069] The vertebral bodies 22 of the spine model 20 are freely
accessible to a user of the system 10. Accordingly, various spinal
constructs, such as a rod 60 and screws 70, may be placed on the
vertebral bodies 22 to allow the user to practice methods of
placing such spinal constructs on a spine and/or to observe the
interaction of the spinal constructs with a spine.
[0070] As shown in FIGS. 11A-13C, in conjunction with FIGS. 7A-10B,
an adjustable rod 60 may include a center member 62 and end members
64. Each end member 64 includes a first segment 64a which slidably
engages an interior surface 62a of the center member 62 that
includes a complementary geometry to that of the first segment 64a.
While the interior surface 62a of the center member 62 is shown as
a continuous, closed square-shaped surface, it should be understood
that the interior surface 62a may have any shape suitable for
slidably engaging end members 64, such as tubular, ovular,
elliptical, or rectangular, for example, among other shapes that
are complementary to the shape of the first segment 64a of the end
members 64. As another example, the interior surface 62a' of a
center member 62' of an adjustable rod 60' may be a semi-continuous
surface, having, for example, a c-shaped profile, as shown in FIGS.
14A-15B. Each end member 64 also includes a second segment 64b that
includes a connecting portion 64c that may be secured to a screw
70.
[0071] It is contemplated that adjustable rod 60, center member 62,
and end members 64 may be used outside of the disclosed spine model
20 and used, in situ, as a standalone spinal implant. In use as a
spinal implant, adjustable rod 60 may be configured as follows.
Center member 62 may include one or more stops that function to
control the expansion and/or contraction of the adjustable rod 60.
In particular, one end member 64 may be fixed relative to center
member 60, while the other end member 64 is slidable between a
minimum amount of extension and a maximum amount of extension with
respect to center member 62. Alternatively, both end members 64 may
be slidable with respect to center member 62 between a minimum
amount of extension and a maximum amount of extension. Further, one
end member 64 may have a different range of travel as compared to
the other end member 64. Further still, one or both end members 64
may be free to expand and inhibited from contracting relative to
center member 62.
[0072] Each end member 64 is shown having a combination
configuration with a portion having an I-beam shape (e.g., first
segment 64a) and a portion with a compound shape (e.g., second
segment 64b). The compound shape includes an elongate round
portion, an elongate head portion, and a neck portion connecting
the elongate round portion with the elongate head portion. It is
contemplated that the entire length of one or both end members 64
has the compound shape and that center member 62 may be configured
to receive the compound shape instead of the I-beam shape as shown
in FIGS. 11A and 11B. It is also contemplated that center member 62
may receive one end member 64 with an I-beam shape and another end
member 64 having a compound shape. It is also within the scope of
the present disclosure that adjustable rod 60 may be used with the
components and/or instruments (e.g., rod reducers, rod benders,
bone screws, etc.) disclosed in U.S. patent application Ser. No.
13/636,416, filed on Nov. 8, 2012 and which published as U.S.
Patent Application Publication No. 2013/0144342, and in U.S. Pat.
No. 8,882,817, both of which are herein incorporated by reference
in their entireties.
[0073] An embodiment of a screw usable with the end members 64 is
shown in FIGS. 16A-16C, generally, as a polyaxial pedicle screw 70'
including a housing 72', a compression ring or cap 74', an anvil
76', a bone screw member 78', and a set screw 80'. The housing 72'
includes opposing walls 72a' and 72b' that define a U-shaped
channel 71' therebetween. The internal surfaces of opposing walls
72a' and 72b' include threaded portions 75' that are threadably
engagable with external threads 82' of the set screw 80' (FIG. 16C)
to facilitate the securement of an end member 64 of an adjustable
rod 60 and 60' (see e.g., FIGS. 11A and 14A) within the channel 71'
of the housing 72' adjacent the anvil 76'. The housing 72' includes
a collar 77' extending therefrom that is adapted to facilitate the
securement of the compression ring or cap 74' to the housing 72'
once the bone screw member 78' is secured to the housing 72'. The
collar 77' has a cut out 77a' that provides a recess for the
reception of a portion of the bone screw member 78', namely a neck
78a', and facilitates the positioning of the bone screw member 78'
within the housing 72' from a distal end of the housing 72'.
[0074] The bone screw member 78' includes a head 78b' and a
threaded shaft 78c' extending from the head 78b'. The bone screw
member 78' may be a self-starting fastener or self-tapping
fastener. The compression ring or cap 74' may be slid over the
threaded shaft 78c' of the bone screw member 78' and affixed to the
collar 77' of the housing 72' to further secure the bone screw
member 78' to the housing 72'. Once inserted, the bone screw member
78' is selectively positionable at plurality of angles relative to
the housing 72' and may be fixedly securable relative to the
housing 72' at a cone angle .alpha. in the range of 60 to 80
degrees, preferably 70 degrees, from the longitudinal axis "L"
extending through the polyaxial pedicle screw 70'. The anvil 76' is
positionable within the housing 72' adjacent the head 78b' of the
bone screw member 78' to facilitate the securement of the end
member 64 within the housing 72'. The set screw 80' is positionable
within the housing 72', e.g., via threading engagement, to secure
the end member 64 within the housing 72' adjacent the anvil
76'.
[0075] As assembled, the pedicle screw 70' is fastenable to a bone
structure (e.g. vertebra) and the housing 72' is repositionable in
a plurality of directions with respect to the bone screw member 78'
as discussed above. To this end, the housing 72' is rotatable about
the longitudinal axis "L" extending through the polyaxial pedicle
screw 70' as well as pivotable relative to the longitudinal axis
"L" and the bone screw member 78'. A connecting portion 64c of an
end member 64 (see e.g., FIG. 13B) is positionable in the U-shaped
channel 71' of the housing 72' and is nested against the anvil 76'.
The end member 64 is then secured to the pedicle screw 70' using
the set screw 80'.
[0076] Another embodiment of a screw usable with the end members 64
is shown in FIGS. 17A-17C, generally, as a multi-planar taper lock
screw 70'' including a dual layered housing 72'' and a screw shaft
74'' having a spherically configured screw head 76'' rotatably
coupled with housing 72''. The taper lock screw 70'' enables
manipulation of the screw shaft 74'' about multiple axes, whereby
the taper lock screw 70'' is capable of releasably securing an end
member 64 of an adjustable rod with taper lock screws 70'' on
multiple vertebral bodies that are aligned in the spinal column on
different planes due to the natural curvature of the spine.
[0077] Dual layered housing 72'' includes an outer housing 72a''
and an inner housing 72b''. Outer housing 72a'' can be selectively
positioned relative to inner housing 72b'' to fully lock screw head
76'' and end member 64 in position within inner housing 72b'' (FIG.
17A), or alternatively to selectively partially lock screw head
76'' and/or end member 64 in position while permitting a sliding
and/or rotating motion of the end member 64 relative to screw head
76'', and the screw head 76'' relative to the housing 72'',
respectively (FIG. 17B). Specifically, outer housing 72a'' is
configured such that at least a portion of an inner surface of
outer housing 72a'' is capable of sliding over a portion of an
outer surface of inner housing 72b'' in upward and downward
directions along the longitudinal axis of taper lock screw 70''.
When outer housing 72a'' is slid upward in relation to inner
housing 72b'' an inner surface of outer housing 72a'' causes inner
housing 72b'' to impart compressive force radially inward to secure
end member 64 at least partially disposed therein.
[0078] Inner housing 72b'' defines a connecting rod slot 78'' that
is configured and dimensioned to accommodate and retain the end
member geometry of end member 64 in the inner housing 72b'' without
impairing the locking ability of the taper lock screw 70''. Inner
walls that define connecting rod slot 78'' imparts compressive
force to end member 64 disposed in connecting rod slot 78'',
whereby the inner walls serve to securely lock and hold end member
64 in its relative position to inner housing 72b''. This required
forced is provided by the operational engagement of a locking
device (not shown) with the taper lock screw 70'' that results in
an upward sliding motion of the outer housing 72a'' relative to the
inner housing 72b''. Inner housing 72b'' further defines a screw
head articulation recess 71'' in a lower portion of inner housing
72b'' that has a complementary surface configuration to the
generally spherical shape of screw head 76'' to facilitate
multi-planar rotational articulation of screw head 76'' within
articulation recess 71''. The lower-most portion of inner housing
72b'' defines a screw shaft exit portal 73'' that is sized small
enough to retain the spherical screw head 76'' within screw head
articulation recess 71'', but that is large enough to allow
multi-directional movement of screw shaft 74'' that extends
exterior to inner housing 72b''.
[0079] One suitable taper lock screw is commercially available from
K2M, Inc. (Leesburg, Va.) under the trade name MESA.TM.. In
addition, suitable multi-planar taper lock screws are shown and
described in U.S. Patent Application Publication No. 2008/0027432
and in U.S. Patent Application Publication No. 2007/0093817, both
of which are herein incorporated by reference in their entireties.
It is contemplated that other types of screws such as, e.g., a
fixed screw in which the head of the screw has no movement relative
to the screw shaft, a mono-axial screw such as that disclosed in
U.S. Patent Application Publication No. 2009/0105716, and a
uni-axial screw such as that disclosed in U.S. Patent Application
Publication No. 2009/0105769 may be utilized. Suitable mono-axial
and uni-axial screws are also commercially available under the
trade name MESA.TM..
[0080] With reference again to FIGS. 7A-10B, in conjunction with
FIGS. 11A-13C, in use, the screws 70 are implanted, in spaced
relation from each other, into vertebral bodies 22 of the spine
model 20. As the spine movement device 30 is actuated and the
distance between the vertebral bodies 22 increases (for example,
during movement from the first position of FIGS. 7A-8B to the
second position of FIGS. 9A-10B), a force is exerted on the screws
70 moving them away from each other, which in turn moves the end
members 64 relative to the center member 62.
[0081] A number of embodiments have been described. Nevertheless,
it will be understood that various modifications may be made
without departing from the spirit and scope of the disclosure.
* * * * *