U.S. patent application number 13/841158 was filed with the patent office on 2013-08-29 for systems, methods and devices for correcting spinal deformities.
This patent application is currently assigned to Reduction Technologies, Inc.. The applicant listed for this patent is Hiram Chee, Richard Ginn, Darin C. Gittings, Ivan Sepetka, Matthew Thompson, David White. Invention is credited to Hiram Chee, Richard Ginn, Darin C. Gittings, Ivan Sepetka, Matthew Thompson, David White.
Application Number | 20130226241 13/841158 |
Document ID | / |
Family ID | 43309193 |
Filed Date | 2013-08-29 |
United States Patent
Application |
20130226241 |
Kind Code |
A1 |
Thompson; Matthew ; et
al. |
August 29, 2013 |
SYSTEMS, METHODS AND DEVICES FOR CORRECTING SPINAL DEFORMITIES
Abstract
Provided herein are systems, devices and methods for the
correction of spinal deformities with the use one or more
implantable rods configured to apply a corrective force to the
spine. Methods of minimally invasive implantation of a corrective
system are provided, such as where the corrective system is
attached only to the spinous process of one or more vertebral
bodies. Various corrective systems as well as components thereof
are also provided, such as those that allow limited movement with
respect to the spinal column.
Inventors: |
Thompson; Matthew; (Corte
Madera, CA) ; Chee; Hiram; (Santa Cruz, CA) ;
Ginn; Richard; (Gilroy, CA) ; Gittings; Darin C.;
(Sunnyvale, CA) ; Sepetka; Ivan; (Los Altos,
CA) ; White; David; (Morgan Hill, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Thompson; Matthew
Chee; Hiram
Ginn; Richard
Gittings; Darin C.
Sepetka; Ivan
White; David |
Corte Madera
Santa Cruz
Gilroy
Sunnyvale
Los Altos
Morgan Hill |
CA
CA
CA
CA
CA
CA |
US
US
US
US
US
US |
|
|
Assignee: |
Reduction Technologies,
Inc.
Corte Madera
CA
|
Family ID: |
43309193 |
Appl. No.: |
13/841158 |
Filed: |
March 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12795975 |
Jun 8, 2010 |
8419772 |
|
|
13841158 |
|
|
|
|
61185079 |
Jun 8, 2009 |
|
|
|
Current U.S.
Class: |
606/254 |
Current CPC
Class: |
A61B 17/707 20130101;
A61B 2017/00867 20130101; A61B 17/7049 20130101; A61B 17/7004
20130101; A61B 17/7028 20130101; A61B 17/809 20130101; A61B 17/7019
20130101; A61B 17/70 20130101; A61B 17/7068 20130101; A61B 17/7025
20130101; A61B 17/701 20130101; A61B 17/7031 20130101 |
Class at
Publication: |
606/254 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Claims
1. A medical system configured to treat scoliosis, comprising: a
first strut-like member; a second strut-like member coupled with
the first strut-like member such that the first and second
strut-like members can slide with respect to each other and pivot
with respect to each other; wherein the first and second strut-like
members are each positionable adjacent a first and second vertebral
body, respectively, and at least one of the first and second
strut-like members is configured to apply a corrective force in the
coronal plane to at least one of the vertebral bodies when
implanted within a patient.
2. The medical system of claim 1, wherein the first and second
strut-like members comprise a material that exhibits a corrective
return force upon bending.
3. The medical system of claim 2, wherein the first and second
strut-like members comprise nitinol.
4. The medical system of claim 1, wherein the first strut-like
member has a longitudinal slot, the system further comprising a
guide element configured to couple the second strut-like member to
the first strut-like member through the longitudinal slot such that
the guide element is slidable within the longitudinal slot and the
first and second strut-like members can pivot with respect to each
other about the guide element.
5. The medical system of claim 4, further comprising a third
strut-like member having a longitudinal slot and a fourth
strut-like member, wherein the guide element is further configured
to couple the third strut-like member to the fourth strut-like
member through the longitudinal slot such that the guide element is
slidable within the longitudinal slot of the third strut-like
member and the third and fourth strut-like members can pivot with
respect to each other around the guide element.
6. The medical system of claim 5, further comprising a spacer
positioned on the guide element such that the first and second
strut-like members reside on one side of the spacer and the third
and fourth strut-like members reside on the second side of the
spacer.
7. The medical system of claim 6, wherein the spacer has a width
configured to match substantially the width of a spinous
process.
8. The medical system of claim 6, wherein the strut-like members
are slidable along a longitudinal axis of the guide element, the
system further comprising: a first bias element positioned between
a first end of the guide element and the first and second
strut-like members, the first bias element being configured to bias
the first and second strut-like members away from the first end of
the guide element; and a second bias element positioned between a
second end of the guide element and the third and fourth strut-like
members, the second bias element being configured to bias the third
and fourth strut-like members away from the second end of the guide
element.
9. The medical system of claim 6, wherein the guide element is
configured to be mounted to a spinous process.
10. The medical system of claim 4, wherein the strut-like members
are slidable along a longitudinal axis of the guide element, the
system further comprising: a bias element positioned between a
first end of the guide element and the first and second strut-like
members, the bias element being configured to bias the first and
second strut-like members away from the first end of the guide
element.
11. The medical system of claim 1, wherein the first and second
strut-like members are pivotally coupled together by way of at
least one intervening strut-like member.
12. The medical system of claim 1, further comprising: a first
engagement device configured to couple the first strut-like member
to the first vertebral body; and a second engagement device
configured to couple the second strut-like member to the second
vertebral body.
13. The medical system of claim 12, wherein the first and second
engagement devices are configured to couple with the spinous
processes of the first and second vertebral bodies,
respectively.
14. The medical system of claim 1, wherein the first and second
strut-like members are configured to be pivotable in the sagittal
plane when implanted within a patient.
15. The medical system of claim 1, wherein the system is configured
such that no corrective force is applied in the sagittal plane when
implanted within the patient.
16. The medical system of claim 1, wherein the first and second
strut-like members are plates.
17. A medical system for the treatment of scoliosis, comprising: a
strut-like member having first and second end portions and a
longitudinal slot in the first end portion, the strut-like member
being configured to exert a corrective force; a first engagement
device configured to couple the first end portion of the strut-like
member to a first vertebral body, the first engagement device
having an elongate element slidable within the longitudinal slot
such that the first end portion is retained with respect to the
first vertebral body and slidable and pivotable with respect to the
first vertebral body; and a second engagement device configured to
pivotally couple the second end portion of the strut-like member to
a second, adjacent vertebral body.
18. The medical system of claim 17, wherein the strut-like member
has a predetermined curvature.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 12/795,975, filed Jun. 8, 2010, which claims the benefit of
U.S. Provisional Application Ser. No. 61/185,079, filed Jun. 8,
2009, all of which applications are hereby incorporated by
reference in their entirety.
FIELD OF THE INVENTIONS
[0002] The subject matter described herein relates generally to the
correction of spinal deformities.
BACKGROUND OF THE INVENTIONS
[0003] Scoliosis, a disease that deforms the spine, affects more
girls than boys and manifests itself during the teen years when
significant growth is experienced. Scoliosis generally combines a
horizontal torsion and flexion in a frontal plane and develops in
three spatial dimensions. As noted, the disease generally begins
with the growth phase, as it is hypothesized that this is probably
due to the rotation of one or two vertebral bodies.
[0004] Sufferers of scoliosis are generally treated initially with
a rigid corset-like orthopedic brace. If this treatment proves
unsuccessful, another treatment option can include spinal fusion
through invasive surgery. Spinal fusion can oftentimes largely
correct a spinal deformity but can also result in complications,
such as when the patient advances into adult life. Spinal fusion
requires significant invasive surgery, oftentimes including the
dissection of the paraspinous muscles of the vertebral body and
exposure of the facet joints and laminae. Typical treatment devices
include one and oftentimes two rods mounted on either side of the
spinal column. If two rods are employed, anchoring means are
provided for positioning the rods in spaced-apart parallel
alignment. Hooks or screws are employed to anchor the rods along
the selected portion of the spinal column for treatment, typically
requiring relatively deep penetration of the cortical bone above
one or both of the pedicles. The anchors are rigidly locked to the
associated rod to prevent relative motion therebetween, and the
entire arrangement can be supplemented with bone grafts.
[0005] Similar systems have been proposed to treat scoliosis
without directly fusing adjacent vertebral bodies. However, because
the implantation procedure is so invasive, it can lead to increased
blood loss, generation of scar tissue and may induce the risk that
the vertebral bodies will still fuse through reaction of the body
itself, i.e., auto-fusion.
[0006] Others have suggested improvements to the orthosis described
above. For example, U.S. Pat. No. 6,554,831 suggests a system that
allows for may intraoperative correction and micro-movement of the
vertebrae despite implantation of a corrective rod. The '831 patent
teaches use of a rigid dual-rod arrangement with fixed and mobile
brackets that are anchored to the transverse process and, thus,
require significant invasive surgery and risk consequent fusion.
The '831 patent discloses attaching a curved rod to a connector
device that is, in turn, attached to a pedicle screw by way of a
ball-and-socket joint for the purpose of allowing articulation
between the rod and the screw. However, this configuration allows
the curved rod to rotate out of alignment with the spinal column
and, consequently, shifts the direction in which the corrective
force is intended to be applied. Use of the ball-and-socket joint
with a fixed bracket further causes the point of articulation to be
undesirably offset from the rod itself.
[0007] U.S. Pat. No. 5,672,175 suggests another approach that
theoretically provides a patient with close-to-normal range of
motion of the vertebrae by instrumenting the spine with elastic
members pre-curved to correct the spinal deformity. Anchoring to
the transverse process is also employed, which, again, is a major
drawback in performing the techniques suggested in the '175 patent.
Further, this device theoretically overcomes the deformity with
constant force applied by pre-curved correction members, but this
does not allow for resultant changes in the deformity or tissue
relaxation. Because of the use of these pre-curved rods, the
technique suggested in the '175 patent may actually result in a
final deformity completely opposite to the original deformity due
to tissue growth and relaxation. Furthermore, this device risks
alteration of the natural biomechanics of the spine by fixing the
distance between points of attachment. This prohibits any change in
distance between pedicles, which shifts the center of rotation of
each affected vertebral body anteriorly.
[0008] U.S. Pat. No. 4,697,582 suggests a correction apparatus that
employs an elastic rod or a pair of elastic rods exhibiting a
memory shape of the corresponding part of a normal rachis, the rods
being immobilized in rotation in each of the guidance openings.
However, the mechanical assembly suggested in the '582 patent is
appended to an area on each vertebrae between the spinal process
and transverse process, which, again, results in significant
invasive surgery, (as discussed earlier) and can result in fusion
of vertebral bodies in the to-be corrected region.
[0009] Therefore, a spinal correction system is needed to correct
spinal deformities while eliminating or significantly reducing the
drawbacks of conventional systems.
SUMMARY
[0010] Provided herein are systems, devices and methods for the
correction of spinal deformities with the use of one or more
implantable rods or other corrective devices, configured to apply a
corrective force to the spine. These systems, devices and methods
are provided herein by way of example embodiments, which are in no
way intended to limit the subject matter beyond that of the express
language of the appended claims.
[0011] Numerous minimally invasive implantation methods are
provided, including attachment of the spinal correction system to
the patient's spinal column without exposure of the vertebral facet
joints. In other embodiments, attachment occurs only to the spinous
process of one or more vertebral bodies with varying degrees of
invasiveness. Also, example embodiments of corrective systems and
devices and methods for attachment of the system are provided. For
instance, certain embodiments include connectors that couple with
the patient's spinal column and allow limited motion of the rod (or
other corrective device) in relation thereto.
[0012] Other systems, methods, features and advantages of the
subject matter described herein will be or will become apparent to
one with skill in the art upon examination of the following figures
and detailed description. It is intended that all such additional
systems, methods, features and advantages be included within this
description, be within the scope of the subject matter described
herein, and be protected by the accompanying claims. In no way
should the features of the example embodiments be construed as
limiting the appended claims, absent express recitation of those
features in the claims.
BRIEF DESCRIPTION OF THE FIGURES
[0013] The details of the subject matter set forth herein, both as
to its structure and operation, may be gleaned in part by the study
of the accompanying figures in which like reference numerals refer
to like parts. The components in the figures are not necessarily to
scale, emphasis instead being placed upon illustrating the
principles of the subject matter. Moreover, all illustrations are
intended to convey concepts where relative sizes, shapes and other
detailed attributes may be illustrated schematically rather than
literally or precisely.
[0014] FIG. 1A is a lateral view of an example spinal column.
[0015] FIG. 1B is a posterior view of an example spinal column.
[0016] FIGS. 1C-D are lateral views of example portions of a spinal
column.
[0017] FIG. 1E is a superior view of an example vertebral body.
[0018] FIG. 1F is a posterior view of an example portion of a
spinal column.
[0019] FIG. 2A is a posterior view depicting an example embodiment
of a spinal correction system implanted within a patient.
[0020] FIG. 2B is a lateral view depicting an example embodiment of
a spinal correction system implanted within a patient.
[0021] FIGS. 2C-D are cross-sectional views depicting example
embodiments of a spinal correction system.
[0022] FIG. 2E is a perspective view depicting an example
embodiment of a spinal correction system implanted within a
patient.
[0023] FIG. 2F is a cross-sectional view taken along line 2F-2F of
FIG. 2E.
[0024] FIGS. 2G-H are cross-sectional views of additional example
embodiments of a spinal correction system.
[0025] FIGS. 2I-J are perspective views of additional example
embodiments of a spinal correction system.
[0026] FIGS. 3A-B are cross-sectional views depicting example
embodiments of a rod for a spinal correction system.
[0027] FIG. 3C is a side view depicting an example embodiment of a
spinal correction system implanted within a patient.
[0028] FIGS. 4A-B are perspective views depicting example
embodiments of attachment devices.
[0029] FIGS. 4C-E are perspective views depicting example
embodiments of attachment devices during implantation.
[0030] FIG. 4F is a perspective view depicting an example
embodiment of a spinal correction system implanted within a
patient.
[0031] FIGS. 5A-E are perspective views depicting example
embodiments of attachment devices.
[0032] FIG. 5F is a posterior view depicting an example embodiment
of an attachment device.
[0033] FIG. 5G is an exploded cross-sectional view depicting an
example embodiment of an attachment device.
[0034] FIGS. 5H-L are perspective views depicting additional
example embodiments of attachment devices.
[0035] FIG. 6A is a perspective view depicting an example
embodiment of an attachment device.
[0036] FIGS. 6B-C are cross-sectional views depicting stages of
implantation of an example embodiment of an attachment device.
[0037] FIGS. 7A-C are perspective views depicting stages of
implantation of an example embodiment of an attachment device.
[0038] FIGS. 7D-E are cross-sectional views depicting example
embodiments of attachment devices.
[0039] FIGS. 8A-B are cross-sectional views depicting stages of
implantation of an example embodiment of an attachment device.
[0040] FIG. 9 is a perspective view depicting an example embodiment
of an attachment device.
[0041] FIGS. 10A-B are perspective views depicting stages of
implantation of an example embodiment of an attachment device.
[0042] FIGS. 11A-D are cross-sectional views depicting stages of
implantation of example embodiments of attachment devices.
[0043] FIG. 12A is a perspective view depicting an example
embodiment of a toroidal element.
[0044] FIG. 12B is a cross-sectional view depicting an example
embodiment of an attachment device.
[0045] FIGS. 12C-D are perspective views depicting example stages
of casting an example embodiment of an attachment device.
[0046] FIGS. 13-14 are flowcharts depicting example methods of
implantation of a spinal correction system.
[0047] FIGS. 15A-D are perspective views depicting example stages
of implantation of a spinal correction system.
[0048] FIG. 16 is a flowchart depicting an example method of
implantation a spinal correction system.
[0049] FIG. 17 is a lateral view depicting an example embodiment of
a spinal correction device.
[0050] FIG. 18 is a lateral view of a spinal column having an
example embodiment of a treatment system attached thereto.
[0051] FIG. 19A is a perspective view of an example embodiment of a
fixed connector coupled to a spinous process.
[0052] FIG. 19B is a side view of an example embodiment of a fixed
connector.
[0053] FIG. 19C is a top-down view of an example embodiment of a
fixed connector.
[0054] FIG. 19D is a perspective view of the upper side of an
example embodiment of the inner housing of a fixed connector.
[0055] FIGS. 19D-E are perspective views of the upper side of
example embodiments of the inner housing of a fixed connector.
[0056] FIG. 19F is a perspective view of the upper side of an
example embodiment of the outer housing of a fixed connector.
[0057] FIG. 19G is a perspective view of the lower side of an
example embodiment of the outer housing of a fixed connector.
[0058] FIG. 20A is a perspective view of an example embodiment of a
slidable connector coupled to a spinous process.
[0059] FIG. 20B is an end-on view of an example embodiment of a
slidable connector.
[0060] FIG. 20C is a perspective view of an example embodiment of
the outer housing of a slidable connector.
[0061] FIG. 20D is a perspective view of the upper side of an
example embodiment of the inner housing of a slidable
connector.
[0062] FIG. 20E is a perspective view of the lower side of an
example embodiment of the inner housing of a slidable
connector.
[0063] FIG. 20F is a perspective view of the upper side of another
example embodiment of the inner housing of a slidable
connector.
[0064] FIG. 20G is an end-on view of example embodiments of the
inner housing of a slidable connector.
[0065] FIG. 20H is a perspective view of an example embodiment of a
tubular housing of a slidable connector.
[0066] FIG. 20I is a longitudinal cross-sectional view of an
example embodiment of a tubular housing of a slidable
connector.
[0067] FIG. 21 is a perspective view of another example embodiment
of a slidable connector coupled to a spinous process.
[0068] FIGS. 22A-C are side views of another example embodiment of
a treatment system in various states.
[0069] FIG. 22D is a top-down view of another example embodiment of
a treatment system.
[0070] FIGS. 22E-F are posterior views depicting another example
embodiment of a treatment system coupled with a corrected and
deformed spinal column, respectively.
[0071] FIG. 22G is an exploded perspective view depicting another
example embodiment of a treatment system coupled with a spinal
column.
[0072] FIG. 22H is a posterior view depicting another example
embodiment of a treatment system coupled with a corrected spinal
column.
[0073] FIG. 22I is a side view depicting another example embodiment
of a treatment system coupled with a spinal column in a state of
extension.
[0074] FIG. 22J is a posterior view depicting another example
embodiment of a treatment system coupled with a corrected spinal
column.
[0075] FIG. 22K is a side view of another example embodiment of a
treatment system.
[0076] FIG. 23A is a bottom-up view of another example embodiment
of a treatment system.
[0077] FIGS. 23B-24 are perspective views of additional example
embodiments of a treatment system coupled to a spinal column.
DETAILED DESCRIPTION
[0078] To facilitate the description of the systems, devices and
methods provided herein, a discussion will first be set forth of
basic healthy spinal anatomy and deformities that can occur
thereto. FIG. 1A is a lateral view of a normal human spinal column
10. Spinal column 10 is divided into three principal regions. The
top, or superior, region 2 includes seven vertebral bodies 11 and
is referred to as the "cervical" region of the spine. These seven
bodies are consecutively labeled C1-C7. The intermediate region 3
includes twelve vertebral bodies 11 and is referred to as the
"thoracic" region of the spine. These twelve bodies are
consecutively labeled T1-T12. The bottom, or inferior, region 4
includes five vertebral bodies 11 and is referred to as the
"lumbar" region. These five bodies are consecutively labeled
L1-L5.
[0079] In a general sense, a typical healthy spinal column 10 has
curvature in the sagittal plane (depicted in FIG. 1A) but not in
the coronal plane (depicted in the posterior view of FIG. 1B).
Referring to FIG. 1A, from a lateral perspective, the curvature of
cervical region 2 and lumbar region 4 can be generally described as
concave (lordotic), while the curvature of thoracic region 3 can be
generally described as convex (kyphotic). Spinal deformities occur
when the curvature in any of regions 2-4 changes to an undesirable
degree, inhibiting the patient's appearance and/or ability to move
and possibly causing pain and/or dysfunction of the nervous system,
as well as other symptoms.
[0080] Spinal deformities can result from excessive curvature,
insufficient curvature or straightening ("flat-back") or even
reversal of the curvature of any or all of the spinal regions 2-4
in the sagittal plane, as well as the introduction of lateral
(i.e., side-to-side) curvature of any or all of the regions 2-4 in
the coronal plane. For instance, excessive kyphotic curvature of
thoracic region 3 of the spine is referred to as hyper-kyphosis and
excessive lordotic curvature of lumbar region 4 is referred to as
hyper-lordosis. Lateral curvature in any of regions 2-4 is
generally referred to as scoliosis. Particularly severe spinal
deformities, such as scoliosis, can also include pronounced
rotation of the vertebral bodies 11. These deformities can involve
complex variations from the alignment of a healthy spine in all
three spatial dimensions and can occur across the entire length of
the spine.
[0081] FIG. 1C is a lateral view of lumbar region 4 of a spinal
column 10 showing the five lumbar vertebral bodies 11 (labeled
L1-L5, respectively), each separated by an intervertebral disc 19.
Each vertebral body 11 includes a posterior portion 12 having
numerous bony features. The most prominent feature is spinous
process 14, which is an elongate, somewhat quadrilateral,
fin-shaped feature that is situated the farthest posteriorly from
each vertebral body 11. Located adjacent to spinous process 14 are
left and right transverse processes 15 and left and right mamillary
processes 16 (only the left side of each is shown here). These
processes 14-16 are connected to each vertebral body 11 by way of
left and right pedicles 17 (again, only left side shown).
[0082] FIG. 1D is a lateral view of three lumbar vertebrae L1-L3 of
spinal column 10 with the left side pedicles 17 and processes 15-16
omitted to allow depiction of the interspinous tissue 20. Located
adjacent each vertebral body 11 and generally anterior to spinous
process 14 (indicated as being obscured by dashed lines) is
ligamentum flavum 41, which is immediately adjacent the
intervertebral foramen 26. Posterior to ligamentum flavum 41, is
the wider interspinous ligament 42 which extends along each side of
each spinous process 14. Posterior to interspinous ligament 42 is
supraspinous ligament 43, which generally extends along the
posterior edge of each spinous process 14 and the interspinous
tissue 20.
[0083] FIG. 1E is a top-down view of a lumbar vertebral body 11.
Here, left and right pedicles 17-1 and 17-2 can be seen in greater
detail extending away from vertebral body 11. With regards to the
reference scheme used herein, generally, specific ones of a similar
element (e.g., left and right pedicles 17-1 and 17-2) will be
referred to using the appendix -#, where the # corresponds to a
specific one (e.g., 1, 2, 3 . . . N) of a similar element. When
general references are made to the elements such that
identification of the specific ones is not required, then the -#
appendix will be omitted.
[0084] Also shown is spinous process 14, left and right transverse
processes 15-1 and 15-2, mamillary processes 16-1 and 16-2 and left
and right laminae 18-1 and 18-2. The spinous process 14 converges
with each lamina 18-1 and 18-2 within a laterally disposed flaring
transitional region. This convergence occurs generally along the
apex 24-1 and 24-2 of each flaring transitional region,
respectively. Anterior to each lamina 18 is a space referred to as
the vertebral foramen 25. It is through the vertebral foramen 25
(shown in FIG. 1E) and intervertebral foramen 26 (shown in FIG. 1D)
that the spinal cord and other spinal nerves (not shown) are
routed.
[0085] FIG. 1F is a posterior view of two vertebral bodies 11,
specifically L3 and L4. Left transverse process 15-1 and right
transverse process 15-2 are shown extending laterally from each
side of bodies 11. Superior to transverse processes 15 are
mamillary processes 16-1 and 16-2 and superior articular processes
22-1 and 22-2. Posterior to transverse processes 15 are the left
and right laminae 18-1 and 18-2, respectively. At the base of each
vertebral body 11 are inferior articular processes 21-1 and 21-2.
The joint or interface between superior articular processes 22 and
inferior articular processes 21 of the adjacent vertebral body 11
is referred to as facet joint 29, of which a left facet joint 29-1
and a right facet joint 29-2 are depicted here between L3 and L4.
Each vertebral body 11 has two sets of facet joints 29, formed in
part by the superior articular process 22 at one end and the
inferior articular process 21 at the opposite end.
[0086] Facet joints 29 are hinge-like and link adjacent vertebral
bodies 11 together. Facet joints 29 are referred to as synovial
joints, which means that each joint 29 is typically surrounded by a
capsule of connective tissue and produces a fluid to nourish and
lubricate the joint. The joint surfaces are coated with cartilage
to allow smooth motion articulation between adjacent bodies.
Dissection of tissue from, and/or exposure of, the facet joint 29
can lead to auto-fusion, especially in younger patients.
Auto-fusion is the internal fusion of adjacent vertebral bodies 11
together by the patient's own body, and severely diminishes the
patient's freedom of motion. Auto-fusion can also be caused by
exposure of one or both of the laminae 18.
[0087] The systems, devices and methods provided herein are
configured to correct spinal deformities through the application of
corrective forces to the spinal column. Preferably, one or more
flexible, shape-memory rods are implanted in close proximity to the
spinal column. The rods are preferably formed from metals or metal
alloys such as nickel-titanium alloys (e.g., nitinol), titanium,
elgiloy, stainless steel, and the like, or polymeric materials such
as Liquid Crystal Polymers (LCP), polyetheretherketone (PEEK),
tert-butyl acrylate, poly(ethylene glycol) dimethacrylate,
polyetherurethane, and the like. The polymeric materials may be
modified to increase their strength and toughness with fillers,
such as fiber, graphite and the like. Unless otherwise noted, this
description will be of a system incorporating dual rods located on
opposite sides of the spinal column.
[0088] These rods are preferably preshaped or shape-set to a
curvature that when applied to a deformity results in a healthy
spine. For example, for treatment of each of the three regions of
the spinal column, the rods are configured with kyphotic curvature
in the portion corresponding to the thoracic region and lordotic
curvature in the portions corresponding to the cervical and lumber
regions. The rods are then distorted during placement over the
deformed portion of the spine such that the rods then apply a
corrective force to the spine. Thus, even if the spinal deformity
bridges into multiple regions of the spine (cervical, thoracic,
lumber), the rods are configured to correct for those corresponding
changes in lordosis and kyphosis.
[0089] Alternatively, one or more straight rods (or equivalent
corrective devices) can be used while preserving the proper
lordotic and kyphotic curvature. For instance, one rod that is
generally straight in the sagittal plane, but it has curvature in
the coronal plane, and can be coupled to the spinal column at
various vertebral bodies. The distance between the rod and
vertebral body can be varied to accommodate the proper lordotic and
kyphotic curvature. In another example, multiple individual rods
can be used, with each being generally straight in the sagittal
plane and curved in the coronal plane. These rods can be positioned
end-to-end along the portion of the spinal column to be corrected.
As opposed to the single-rod example, the distance between the ends
of each rod and the vertebral bodies can be generally fixed, but
each rod can be coupled at the appropriate angle to simulate the
lordotic and/or kyphotic curvature, effectively replacing a rod
with curvature in the sagittal plane with multiple straight rods
arranged to match the curvature in the sagittal plane.
[0090] Preferably, correction occurs by the use of only one set of
implanted rods over the course of treatment, although correction
can also be achieved by way of iterative replacement of the rods.
In such an embodiment, the first set of rods can be shaped to
correct some, but not all, of the deformity in the spinal column
(or can be shaped or sized to resemble a healthy spine but with
relatively less strength, such that it applies corrective force at
a relatively lower level). After that set of rods has been
implanted for a length of time sufficient to cause the incremental
correction, a new set of rods can be implanted with a shape (or
strength) that is configured to achieve incrementally more
correction. This process can be repeated as many times as needed
until the spinal column is corrected to the desired extent. The use
of an iterative process requires multiple surgeries, but can allow
for the use of rods that are relatively more flexible, thereby
allowing the patient greater freedom in movement. The iterative
process also allows the shape of the rods and location of
implantation to be fine-tuned to exert corrective forces where they
are needed to achieve the desired outcome.
[0091] FIG. 2A depicts an example embodiment of a spinal correction
(or corrective) system 100 implanted within a body 30 of a patient.
Here, system 100 includes tubular members 101, each having an inner
lumen 103 for slidably receiving a rod 102. Here, each rod 102 is
received within two tubular members 101, although it should be
noted that any number of one or more tubular members 101 can be
used for each rod 102. For ease of description, tubular members 101
will be referred to herein as sleeves.
[0092] There are at least several benefits for using sleeve 101
outside rod 102. Sleeve 101 facilitates the placement or
replacement of rods 102 by forming a readily accessible pathway for
rod 102 into the implantation space. The new rod would also not
require attachment to the spinous process, as the sleeve 101 is
preferably already attached.
[0093] Also, avoidance of rigid attachment to the bone can be
desired since fixing any member to bone can potentially put large,
localized forces on the bone in the areas of contact. As corrective
rods 102 can be long, they provide the opportunity to place large
moments on the rigid attachment. Allowing rods 102 limited lateral
and rotational freedom of movement within sleeves 101 reduces the
stress placed on the rigid attachment. Sleeves 101 also isolate
bone and tissue from frictional forces generated by the moving rod
102. Sleeves 101 can also contain and isolate any wear particles
that may be generated by movement of rods 102.
[0094] FIG. 2A is a posterior view of system 100 implanted along
spinal column 10. FIG. 2B is a lateral view of the embodiment of
FIG. 2A showing rod 102 and sleeve 101 on the left side of the
spinal column 10. As shown in FIG. 2A, this example of spinal
column 10 exhibits a scoliotic bend to the patient's right for
which correction is desired (patient's head is to the left as
shown). In this embodiment, system 100 includes four sleeves 101-1
through 101-4 and two rods 102-1 and 102-2. Sleeves 101 are shown
in cross section to show rod 102 within. Preferably, each sleeve
101 has an open end 104 for receiving rod 102 and a closed end 105.
Lumen 103 is sized to slidably receive rod 102 while at the same
time allowing limited rotational or lateral movement of rod 102
within lumen 103. Sleeves 101 are preferably formed from a
polymeric material such as polyethylene (PE), polypropylene,
polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE),
fluorinated ethylene/propylene copolymers (FEP), silicones,
hydrogels, hydrophilic coatings, polyurethane (PU), polyethylene
ptherethalate (PET), polyimide, styrene-ethylene-butadiene styrene
(SEBS), and the like.
[0095] Sleeves 101 can also be formed from coiled wire or ribbon or
can be configured as slotted tubes (either polymeric or metallic).
The pattern of the coil or slotted tube can be optimized for
flexibility and pushability. Sleeves 101 can be coated with
lubricious coatings, such as hydrophilic coatings to facilitate
advancement of the sleeve through the surrounding anatomy and to
facilitate introduction or removal of the rods within the
sleeves.
[0096] Here, rod 102-1 is received within superiorly located sleeve
101-1 and inferiorly located sleeve 101-2. Likewise, rod 102-2 is
received within superiorly located sleeve 101-3 and inferiorly
located sleeve 101-4. Sleeves 101 and rods 102 preferably extend a
sufficient amount past the most superiorly and inferiorly vertebral
bodies 11 to be treated in order to accommodate growth and the full
range of motion in any direction (i.e., flexion and extension,
rotation and bending). Sleeves 101 are arranged such that a gap
exists to expose rods 102 such that a rigid rod connector, or
coupling device, 106 can be coupled with each rod 102 to hold rods
102 in position relative to each other and prevent each rod from
rotating significantly with respect to each other and with respect
to the spinal column. For instance, prevention of rotation with
respect to the spinal column precludes the curved portion of the
rod from rotating out of the sagittal plane and into the coronal
plane to accommodate the deformity.
[0097] Although spaces are shown between sleeves 101-1 and 101-3 as
well as sleeves 101-2 and 101-4 to allow direct coupling of rod
connector 106 with each rod 102, this space can be omitted and
sleeves 101-1 and 101-3 can be one continuous sleeve (likewise for
sleeves 101-2 and 101-4). Direct connection to rods 102 can be
foregone with some other measure to prevent rod rotation applied.
Alternatively, apertures can be provided in the sleeves to allow
access to rods 102. Preferably, only one rigid rod connector 106 is
applied between rods 102-1 and 102-2, at a centrally located
position. However, if desired, any number of rigid rod connectors
106 can be applied at any location along the length of system
100.
[0098] Each superiorly located sleeve 101-1 and 101-3 can be
optionally coupled together by way of a lateral coupling device
108-1. Similarly, the inferiorly located sleeves 101-2 and 101-4
can be coupled together by way of a lateral coupling device 108-2.
Coupling device 108 acts to maintain sleeves 101 in position with
respect to each other (e.g., so as to prevent sleeves 101 from
migrating laterally and also to allow the force applied from a rod
on the convex side to act on the deformity). Coupling device 108
can have any configuration suitable for the needs of the
application. Here, coupling device 108 is configured as a band. Any
number of coupling devices 108 can be applied at any location along
the length of system 100.
[0099] In addition, sleeves 101 can be coupled with spinal column
10 by way of a spinal coupling device 109. Here, a superiorly
located spinal coupling device 109-1 couples sleeves 101-1 and
101-3 to a spinous process 14-1. Specifically, spinal coupling
device 109-1 is routed through an iatrogenic, or man-made, opening
110-1, in spinous process 14-1. Opening 110 can be formed by a
piercing element (e.g., guidewire, trocar and the like) or a
drill-like element. An example instrument for piercing the spinous
process is described in the copending U.S. Patent Application Ser.
No. 60/988,432, filed Feb. 7, 2008, and entitled "Hand-held
Instruments That Access the Spinous Process of a Vertebrae," which
is fully incorporated by reference herein. Spinal coupling device
109 can also be configured to be secured partially or entirely
around the spinous process rather than through it. Spinal coupling
device 109 prevents sleeve 101-1 and 101-3 (and, likewise, superior
ends of rods 102-1 and 102-2) from migrating posteriorly away from
spinal column 10 during flexion of spinal column 10. In some
circumstances, spinal coupling device 109 can also prevent sleeves
101 from migrating anteriorly during spinal extension.
[0100] An inferiorly located spinal coupling device 109-2 couples
sleeves 101-2 and 101-4 together through iatrogenic opening 110-2
within an inferiorly located spinous process 14-2. Coupling device
109 can have any configuration suitable for the needs of the
application. Here, coupling device 109 is configured as a tether.
Although only coupling device 109 is shown coupled with the
patient's spinal column 10, rod coupling device 106 can be
optionally coupled to the patient's spinal column (e.g., spinous
process) as well.
[0101] Preferably, system 100 is only coupled to the spinal column
at one superiorly located position and one inferiorly located
position, in order to allow significant freedom of movement to the
patient. However, system 100 can be coupled with the spinal column
at additional locations (e.g., a central location) if desired. For
each location where system 100 is coupled with the spinal column,
the system can be configured to slide superiorly and inferiorly to
accommodate the patient's movement. Rigid rod connector 106 can be
implanted directly through the interspinous ligament and can act as
an anchor for the entire spinal correction system, preventing
significant movement superiorly and inferiorly.
[0102] Sleeves 101 are configured so that they can be tunneled
under the skin either on their own or with the help of an
instrument inserted into the sleeve lumen. The sleeves are
preferably configured to conform to the anatomy in the proximity of
the spinous processes and surrounding tissue as they are advanced.
The sleeves themselves preferably do not impart any corrective
forces, but rather serve as guides for the rods that are placed
through them. In an alternative embodiment, sleeves 101 are
configured with a shape similar to that of the desired healthy
spine. If iterative correction is applied, in order to prevent the
need for removal of sleeves 101 during rod replacement, sleeves 101
are preferably flexible to a degree sufficient to accommodate rods
102 of varying shapes and sizes.
[0103] Upon attachment of corrective system 100, corrective force
is applied to each vertebral body 11 lying adjacent to rods 102.
The force is transmitted to each body 11 through the connection of
the rods or sleeves directly to one or more vertebral bodies, as
well as by the proximity of rods 102 with the spinous processes 14,
the interspinous tissue 20 and/or the various other features of
vertebral bodies 11 within the treatment region.
[0104] The use of an inferiorly and superiorly located sleeve on
either side of the spinal column is also conducive to the use of
multiple rod segments on both sides of the spinal column. For
instance, rod 102-1 can include a first segment received within
superiorly located sleeve 101-1 and a second, separate segment
received within inferiorly located sleeve 101-3. Rigid rod
connector 106 can be configured to couple the rod segments together
as well as fix those segments with respect to rod 102-2 (or
segments thereof) and the spinal column. The use of rod segments
can facilitate the insertion procedure, as will be described in
more detail below.
[0105] It should also be noted that a bundle of two or more rods or
rod segments can be placed on either side of the spinal column. For
instance, in one example embodiment, instead of a superiorly placed
rod segment on the left side of the spinal column, a bundle of
three rod segments can be placed superiorly on the left side of the
spinal column. These three rod segments can couple with a similar
inferiorly placed bundle of three rod segments, or a different
number of inferiorly placed rod segments can be used. Preferably,
the bundle of rods or rod segments is banded or otherwise connected
together and placed within a sleeve, although each rod or rod
segment could be placed within its own sleeve, with the sleeves
then being coupled together.
[0106] FIG. 2C is a perspective view depicting an example
embodiment of spinal correction system 100 having multiple rods 102
arranged in a bundle. FIG. 2C depicts the superiorly located
portion of system 100 including sleeves 101-1 and 101-3. Sleeves
101-1 and 101-3 are shown to be transparent for ease of
illustration of the components therein. FIG. 2D is a
cross-sectional view taken along line 2D-2D of FIG. 2C.
[0107] Received within lumen 103-1 of sleeve 101-1 is a bundle of
three rods 102-1, 102-2 and 102-3, which are held in relation to
each other by coupling device 290-1. Similarly, received within
lumen 103-3 of sleeve 101-3 is a bundle of three rods 102-4, 102-5
and 102-6, which are held in relation to each other by coupling
device 290-3. Coupling devices 290 preferably allow rods 102 to
slide within the respective lumens in coupling devices 290. A
similar arrangement could be present in the inferiorly located
portion of system 100 within sleeves 101-2 and 101-4. Fixed
coupling device 106 is coupled with rods 102-3 and 102-6 of the two
respective bundles. Each rod 102 can include a keyed portion to
maintain the radial orientation of each rod with respect to the
others. Here, the keyed portion is formed by a rib 291 located
along the length of each rod. Ribs 291 are configured to interface
with a complementarily shaped lumen within coupling devices 106 and
290.
[0108] This configuration of system 100 allows the medical
professional to adjust the force applied while minimizing the
effort necessary to remove portions and implant new portions of
system 100. For instance, to lessen the force applied, the medical
professional can simply remove a rod from each bundle. Rods 102-1,
102-2, 102-4 and 102-5 are each preferably only slidably received
within coupling devices 290, making removal relatively simple. Rods
102-3 and 102-6 are preferably left in place to avoid the need to
remove and reattach coupling device 106. Similarly, if an open
lumen is present in coupling devices 290, a rod 102 can be added to
increase the force applied. Use of multiple small rods in a bundled
arrangement can also provide significant improvements in lifetime
and fatigue performance as compared to a single larger rod of the
same material. One of skill in the art will readily recognize that
any number of rods can be used within each bundle.
[0109] FIG. 2E is a perspective cutaway view depicting another
example embodiment of rod 102. Here, rod 102 is configured with
multiple components 141-143 to allow adjustment of the corrective
force applied. FIG. 2F is a cross-sectional view of rod 102 taken
along line 2F-2F of FIG. 2E. Included are an outer tubular
component 141, an inner tubular component 142 and a central core
component 143. Similar to the previous embodiment, this embodiment
allows the applied corrective force to be adjusted with minimal
effort during surgery. Outer tubular component 141 is preferably
coupled with a similar component on the other side of the spinal
column by way of a fixed coupling device (such as coupling device
106 described herein). Adjustment of the applied corrective force
can be accomplished by modification of the components present.
Preferably, the corrective force can be lessened by removal of
inner tubular component 142 or core component 143. Likewise, force
can be added through the addition of components. One of skill in
the art will readily recognize that any number of components can be
present.
[0110] FIG. 2G is a cross-sectional view of an example embodiment
of corrective system 100 where tubular member 101 includes two
through-holes 111 in opposing positions in the side wall through
which a coupling device (e.g., coupling devices 108 or 109
described earlier) can be routed. Through-holes 111 can be offset
to one side of tubular member 101 so as to not interfere with the
movement or location of rod 102 within inner lumen 103.
[0111] FIG. 2H is a cross-sectional view of another example
embodiment of corrective system 100 where tubular member 101
includes one or more (in this example four) raised portions 112
each having an aperture or through-hole 114. A coupling device
(e.g., coupling device 108 or 109) can be routed through one or
more of apertures 114 to couple tubular member 101 with another
tubular member 101 (not shown) or with a portion of the patient's
anatomy, such as spinous process 14 (also not shown).
[0112] The use of multiple raised portions provides the medical
professional with optional locations on tubular member 101 to use
for coupling. For example, the raised portion 112 located in the
most suitable position for coupling to the spinous process can be
selected. Alternatively, the medical professional can couple
through more than one aperture 114 for added security or strength.
For instance, a tether (e.g., braided wire) could be routed through
each of apertures 114 to distribute the load in a relatively
uniform fashion. Here, raised portions 112 are shown arranged in
series longitudinally along the tubular member 101, although it
should be understood that raised portions 112 can also be arranged
radially about the circumference of tubular member 101, or any
combination thereof. Also, instead of raised portions 112, tubular
member 101 can include recessed portions having a strut or hook
about which the coupling device can be routed, giving tubular
member 101 an overall lower profile.
[0113] FIG. 2I is a perspective view of an example embodiment of
system 100 where sleeve 101 includes longitudinal slots, or
cutouts, 247-1 and 247-2, which are configured to allow sleeve 101
and rod 102 to fit closely with the adjacent spinous processes.
Here, only a portion of sleeve 101 is depicted. Slots 247-1 and
247-2 are positioned according to the location of the spinous
processes of the portion of the patient's spinal column to be
treated. Each spinous process is received within the respective
slot 247, allowing rod 102 to be positioned relatively closer to
the spinous process. This can be desirable in applications where
close placement of rod 102 to the spinous process is desired for
increased accuracy or precision in the application of the
corrective force. Also, the close proximity of sleeves 101 and rods
102 to the surface of the vertebrae minimizes the stress placed on
the attachment device. This embodiment of sleeve 101 is
particularly suited to use with attachment devices such as those
embodiments described with respect to FIGS. 5H-L, although not
limited to such. It should be noted that instead of multiple slots
247, only one continuous slot can be present to more freely allow
sleeve 101 to slide back and forth across spinous processes 14, if
desired.
[0114] FIG. 2J is a perspective view of another example embodiment
of spinal correction system 100 where tubular members 101-2 and
101-4 are coupled together by connective portion 115, which is
routed through iatrogenic opening 110 in spinous process 14. Here,
a separate spinal coupling device (e.g., coupling device 109) can
be omitted since the functionality is integrated into tubular
members 101 themselves. To achieve the configuration depicted here,
tubular members 101 are preferably flexible enough to allow
distortion while the tubular member is passed or threaded through
opening 110. The attachment to spinous process 14 preferably occurs
at a superiorly located as an inferiorly located position. Again,
sleeves 101 are preferably formed from a polymeric material such as
polyethylene (PE), polyetheretherketone (PEEK),
polytetrafluoroethylene, fluorinated ethylene/propylene copolymers,
silicones, hydrogels, hydrophilic coatings, polyurethane (PU), and
the like.
[0115] Although spinal correction system 100 preferably includes
sleeves 101 for attachment to spinal column 10, it should be
understood that rods 102 can be directly attached to spinal column
10 with the omission of sleeves 101 altogether. Embodiments of
system 100 that attach to spinal column 10 without reliance on
sleeves 101 are described in the parent U.S. patent application
Ser. No. 11/656,314 and entitled "Orthosis to Correct Spinal
Deformities," which is fully incorporated by reference herein.
[0116] It should be noted that any number of corrective systems 100
can be coupled to spinal column 10 at multiple locations along the
length of spinal column 10. The use of multiple systems 100 allows
relatively more localized correction. Different systems 100 can be
configured to apply different degrees of corrective force in
different directions and can be placed contiguously, or at spaced
apart locations on spinal column 10 leaving vertebral bodies 11 to
which no corrective force is applied. For example, if a spinal
deformity bridged multiple regions (cervical and thoracic, thoracic
and lumbar, all three regions, etc.) of the spinal column, then
different systems 100 could each be targeted to treat those
different regions of the spinal column.
[0117] The use of multiple systems 100 can allow greater freedom of
movement to the patient. Also, in the case where the systems 100
are placed in a partially overlapping manner, less additional
length of each sleeve 101 and rod 102 is required in the regions
extending past the most superiorly and inferiorly located vertebral
bodies to be treated since extra length needed to accommodate full
range of motion and growth over time is distributed among the
multiple systems 100. Also, corrective systems 100 can be made to
overlap such that two sets of rods 102 can apply different amounts
of corrective forces in different directions on the region of the
spine in the overlapping portion. Furthermore, the use of multiple
corrective systems 100 can facilitate implantation and replacement,
depending on the anatomy and the desired strategy for correction.
For instance, with multiple systems 100, replacement can be limited
to only the necessary components to achieve the desired
correction.
[0118] In addition, more than one rod can be used along a single
side of the spinal column, either coupled directly to the spinal
column or placed within or through a sleeve 101. FIG. 11 of the
incorporated application Ser. No. 11/656,314 depicts an example of
a multiple rod configuration where each rod is slidable with
respect to the other. This allows two rods of varying stiffness to
be used as well as allowing the rods to change length during
flexion or extension of the patient's spine.
[0119] Alternatively, FIGS. 3A-B included herein depict an example
embodiment of a telescoping rod 102 for use in system 100. FIG. 3A
is a cross-sectional view showing an example embodiment of rod 102.
Here, rod 102 includes a first rod segment 119-1 and a second rod
segment 119-2 with a piston portion 120 located therebetween. Rod
119-2 includes a hollow portion having a side wall 124 configured
to receive rod 119-1. The hollow portion has a sealing member 123,
such as a gasket, that is configured to encompass rod 119-1 and
guide its movement into the hollow portion. Rod 119-1 includes a
sealing member 121 configured to compress the volume located within
region 122 in a piston-like manner. Depending on the substance
filling the volume of region 122, the amount of force necessary to
compress rods 119-1 and 119-2 toward each other can be varied.
[0120] FIG. 3B is a cross-sectional view depicting another example
embodiment similar to that of FIG. 3A. Here, rod 119-1 has an
enlarged end 125 that is configured to compress a bias element 126
located within chamber 122. In this embodiment, the volume within
chamber 122 does not need to be compressed since the biasing is
provided by bias element 126. Bias element 126 can be any
compressible and expandable structure. Here, bias element 126 is
configured as a spring.
[0121] FIG. 3C shows an example embodiment where three systems
100-1, 100-2 and 100-3, each having a rod 102-1, 102-2 and 102-3,
respectively, are coupled in series along patient's spinal column
10. Here, spinal column 10 is shown in full flexion. Each rod 102
has a fixed connector 128 that fixedly connects the rod to a first
spinous process 14. Each rod can also have one or more slidable
connectors 129 to one or more adjacent spinous processes 14 (only
one slidable connector 129 per rod 102 shown here). Slidable
connector 129 allows rod 102 to slide in relation to the spinous
process 14 to which the slidable connector 129 is attached. Example
slidable connectors are described herein as well as in the
incorporated parent application.
[0122] Turning now to the attachment of spinal correction 100 to
the spinal column, various methods and devices for attachment are
disclosed in the incorporated parent application. These include
U-shaped clamps that are fixedly screwed to the spinous process,
such as that described with respect to FIG. 2 of the parent
application. Also disclosed are opposing plate-like devices that
are screwed through the spinous process and include textured or
spiked surfaces that increase friction with the underlying bone,
such as that described with respect to FIG. 5 of the parent
application.
[0123] Additional attachment devices are provided herein having
various configurations and methods of attachment. It should be
noted that any of these devices can be fixedly screwed to the
patient's spinal column and can take advantage of the use of
textured surfaces or spiked surfaces such as described in the
parent application. Accordingly, those structures and methods of
attachment will not be repeated.
[0124] As will be discussed in more detail herein, attachment to
the patient's spinal column preferably occurs in a minimally
invasive manner to limit the amount of exposure of each vertebral
body attached to the spinal correction system. In a preferred
embodiment, the spinous process is the only portion of those
vertebral bodies in the region to be treated that is exposed during
surgery. Preferably, no tissue anterior to the base of the spinous
process is dissected and exposure of the laminae and facet joints
is avoided. This can prevent undesirable secondary effects (e.g.,
excessive blood loss, scarring, auto-fusion).
[0125] In another embodiment, the spinous process is exposed
without dissecting any portion of the ligamentum flavum coupled
with the vertebral body to which the spinal correction system is
coupled. In yet another embodiment, the spinous process is exposed
without exposing any portion of each lamina anterior to the flaring
transitional region of that lamina. While in yet another
embodiment, only the portion of the spinous process posterior to
the flaring transitions is exposed. Each of these embodiments will,
among other things, reduce the scarring that will occur on or near
the vertebral body of the patient. Accordingly, many of the
embodiments of attachment devices described herein are configured
to engage only the spinous process of each vertebral body,
preferably, posterior to the flaring transitional regions of the
spinous process and the laminae (although these devices can be
configured to attach to other portions of the vertebral body if
desired).
[0126] FIGS. 4A-B are perspective views of example embodiments of
an attachment device 201. Attachment device 201 can be used to
couple any portion of corrective system 100 to the patient's spinal
column 10, preferably the spinous process 14. For instance,
attachment device 201 can be used to couple one or more of tubular
members 101 or flexible rods 102 (neither shown) to spinous process
14. Also, attachment device 201 can be used to couple any other
portion of corrective system 100 to spinous process 14, such as
coupling devices 106, 108 or 109 (also not shown).
[0127] Here, attachment device 201 is generally U-shaped and
includes a first plate-like side portion 202 and a second
plate-like side portion 204 coupled together by an end portion 203.
Plate-like side portions 202 and 204 oppose each other and are
configured to attach to opposing sides of spinous process 14.
Plate-like side portions (or plates) 202 and 204 can be generally
flat, or can have a relatively slight degree of curvature. In FIG.
4A, end portion 203 is placed over the posterior side 27 of spinous
process 14, and in FIG. 4B, end portion 203 is placed over either
the superior or inferior side of spinous process 14. Located on
each plate-like side portion 202 and 204 is an engagement feature
205, which in this embodiment includes a raised portion 206 having
a threaded lumen 207 therein. Engagement feature 205 can be
configured in any manner desired to engage or interlock with the
designated portion of spinal correction system 100 (e.g., sleeve
101, rod 102, coupling device 109, etc.).
[0128] Attachment device 201 can be attached to spinous process 14
using numerous different methods. For instance, attachment device
201 can be advanced over spinous process 14 and crimped onto
spinous process 14 using a crimping tool. In this regard,
attachment device 201 is preferably formed from a crimpable
material such as nitinol, stainless steel, various rigid polymers
and the like. Additional embodiments of attachment device 201
configured to be attached to the spinous process are described in
FIGS. 5A-12B.
[0129] Attachment device 201 can also be configured to be
self-adjusting to attach with spinous process 14, as will be
described with respect to FIGS. 4C-E, 5A, 5D, 5F and 11A-D. FIGS.
4C-E depict an example embodiment of attachment device 201 where
platelike portions 202 and 204 are biased toward each other. FIG.
4C is a top-down view of this embodiment in an at-rest state where
plate-like portions 202 and 204 are in close proximity to each
other. Attachment device 201, in this embodiment, is preferably
formed from an elastic material, such as spring steel, or a
superelastic, shape-memory material, such as nitinol, and biased
toward the at-rest state depicted in FIG. 4C. In addition,
attachment device 201 can be formed from a polymeric material with
attached or integral metallic components configured to apply the
bias.
[0130] Attachment device 201 can then be deformed or deflected from
this at-rest state to an open state such as that depicted in the
top-down view of FIG. 4D. In this deflected state, attachment
device 201 can be advanced over spinous process 14 and released.
Once released, plate-like portions 202 and 204 deflect toward the
at-rest state and exert a clamping force on spinous process 14 as
depicted in FIG. 4E. Advancement and release of attachment device
201 can be facilitated with a delivery device (not shown).
[0131] Alternatively, attachment device 201 can be configured with
thermally dependent shape-memory characteristics. Configuration of
nitinol to exhibit thermally dependent shape-memory characteristics
is well known in the art and will not be discussed herein.
Generally, in such an embodiment, attachment device 201, at room
temperature (or cooler), would be deformed to a state similar to
that depicted in FIG. 4D and would exhibit only a minimal, if any,
bias toward a separate state. Once in place over spinous process
14, attachment device 201 can be deformed to place plate-like
portions 202 and 204 into contact with the opposing sides of
spinous process 14. After implantation, the patient's body heats
attachment device 201 and this heating activates the shape-memory
characteristics to cause attachment device 201 to exhibit a bias
toward a state similar to that depicted in FIG. 4C, thereby causing
attachment device 201 to clamp onto spinous process 14.
[0132] It should be noted that the use of adhesives, preferably
quick-drying adhesives, can also be used to facilitate engagement
of attachment device 212 to spinous process 14. In FIG. 4D, a
quick-drying resin 208 is placed on the inner surface of plate-like
portions 202 and 204. Adhesive 208 can be applied by the medical
professional to the interior of plate-like portions 202 and 204
prior to the implantation procedure or can be pre-placed on
portions 202 and 204 by a third party (e.g., the manufacturer).
Alternatively, or in addition to placement on the inner surfaces of
device 201, adhesive 208 can be applied to spinous process 14 by
the medical professional prior to implantation of attachment device
201.
[0133] FIG. 4F is a perspective view of an example embodiment of
spinal correction system 100 attached to spinous process 14 by way
of attachment device 201 and engagement feature 205 having threaded
lumen 207. Here, sleeve 101 is received within an outer tubular
member 266 which can be either slidably or fixedly coupled to an
outwardly extending strut 267 having an aperture 270 therein.
Aperture 270 is preferably aligned with lumen 207 in engagement
feature 205 such that a screw 268 can be inserted through aperture
270 and into threaded lumen 207. Screw 268 is tightened until
enlarged head portion 269 of screw 268 contacts strut 267 and
provides the desired amount of fastening.
[0134] One of skill in the art will readily recognize, based on the
description provided herein, that numerous types of engagement
features 205 configured for many different types of attachment can
be provided including, but not limited to, threaded (e.g., screw)
features, latch features, snapable features, hookable features,
crimpable features, clampable features, features for wired
attachment, features to facilitate attachment with adhesives, and
the like.
[0135] In another example embodiment, the surface of the spinous
process can be modified to create recesses in which the attachment
device 201 can be seated. For instance, with a U-shaped attachment
device, a U-shaped chisel can be used to create grooves or slots on
either face of the spinous process. The grooves could be sized to
receive the entire attachment device, or could complement keels or
spikes on the inner surface of the portions 202 and 204. Portions
202 and 204 can then be tapped onto the spinous processes to anchor
the keels or spikes into the grooves.
[0136] FIGS. 5A-F depict additional example embodiments of
attachment device 201 where device 201 is configured to surround
the periphery of spinous process 14. One advantage of these
configurations is that the devices 201 can be introduced laterally
as opposed to posteriorly, which lessens the disruption and
dissection of the interspinous ligament. An engagement feature 205
is shown on the near side of the spinous process 14 in FIGS. 5A-E,
and can also be included on the opposite side as well. In the
perspective view of FIG. 5A, attachment device 201 includes an
elastic band 210 with a relatively more rigid section 211 thereon.
Engagement feature 205 is located on rigid section 211, both of
which can also be present on the opposite side of spinous process
14. Elastic band 210 is preferably composed of a biocompatible,
polymeric material having sufficient life span to retain its
structural integrity and elasticity over the duration of
implantation, such as silicone or polyurethane, and the like.
[0137] FIG. 5B is a perspective view of another example embodiment
of attachment device 201 where device 201 includes a strap-like
member 212 having a first end 213 configured to slide into and be
received by an opposing, second end 215 having a lumen therein. End
213 preferably includes engageable elements 214, which in this case
are ribs or ridges in the surface of strap 212. Engageable elements
214 are preferably configured to interface with an opposing feature
within end 215, such that a tightening motion is allowed, but the
reverse motion (un-tightening) is prevented by the opposing
features. The embodiment can operate in a "zip-tie" fashion, that
is, the user advances end 213 through end 215, continually passing
engageable elements 214 through end 215 until the desired tightness
or compressive force is exerted, at which point reverse motion is
prevented. Here, engagement feature 205 is located on the outer
surface of end 215. Alternatively, strap 212 can be made of woven
fibers made from polymers such as polytetrafluoroethylene (PTFE),
polyethylene ptherethalate (PET) or ultrahigh molecular weight
polyethylene (UHMWPE) or metal filaments such as nitinol, stainless
steel, titanium alloys, and the like. The engagement feature 205
could be configured as a buckle.
[0138] In the perspective view of FIG. 5C, attachment device 201
includes a flexible band 218 having opposing ends that are coupled
together by a crimpable structure 219. Here, band 218 is placed
over spinous process 14 with the desired amount of tension or
compressive force, and crimpable structure 219 is then crimped over
the ends to fasten them with relation to each other. Instead of a
crimpable structure, a clamp, a snap or the like can also be used.
In addition, self-tightening fasteners can be used. Alternatively,
crimpable structure 219 can have two lumens to accommodate either
end of the flexible band.
[0139] In the perspective view of FIG. 5D, engagement feature 205
is located on a plate-like base 220. Base 220 is maintained in
place on spinous process 14 by a compressible coil 221. Adhesives
can be used to facilitate the attachment of plate-like base 220 to
spinous process 14 as well. Coil 221 is preferably deformed from a
relatively smaller state around spinous process 14 such that it
continues to exert a significant compressive force to hold
plate-like base 220 in place. Base plate 2220 can also include
features to facilitate attachment or placement of coil 221, such as
eyelets, hooks, guides, recesses, and the like. Coil 221 can be
formed from any elastic material including but not limited to
nitinol, stainless steel, polymers, elgiloy, and the like.
[0140] In the perspective view of FIG. 5E, attachment device 201
again includes a strap or band 212 having ends 213 and 215, with
end 215 configured to receive end 213 within an inner lumen. End
213 preferably includes ridged or otherwise ratchetable elements
222, which are configured to operate with a ratchet 223 located on
and within end 215. Here, ratchet (or screw drive) 223 is
configured to be turned (either in a clockwise or counterclockwise
fashion) to increase or decrease the tension on strap 212 by
interfacing with ratchetable elements 222. Again, engagement
feature 205 is located on end 215. In an alternative embodiment,
attachment device 201 can be configured such that ratchetable
elements 222 are grooves or holes in the center of band 212, as
opposed to ridges on the edge of each band 212. In the embodiments
of FIGS. 5B and 5E, an opposing engagement feature 205 can be
placed directly on strap 212 on the opposite side of spinous
process 14.
[0141] FIG. 5F is a posterior view of another embodiment of
attachment device 201 located on spinous process 14. Here,
attachment device 201 includes two bodies 224 and 225, each having
plate-like portions configured to oppose each other, as well as
interlocking features 226 and 227 on the opposing ends. Here, each
interlocking feature 226 and 227 is formed by complimentary
hook-like features on each body 224 and 225. These features are
preferably configured to maintain attachment device 201 in place
over spinous process 14 by inducing deflection in bodies 224 and
225 to compress the spinous process 14 located therebetween.
Alternatively, bodies 224 and 225 can be threaded or perforated at
one end so compression is achieved by tightening a screw or other
adjustable device disposed through both bodies 224 and 225.
[0142] FIG. 5G is an exploded cross-sectional view depicting
another example embodiment of an attachment device 201, including
cannulated elements configured to be positioned over a guidewire
156. Specifically, opposing plates 153 and 154, both having lumens
163 and 164, respectively, are positioned on opposing sides of
spinous process 14, having iatrogenic opening 110, which in this
embodiment need only be large enough to allow passage of guidewire
156 therethrough. Guide elements 152 and 155 have a washer-like
configuration and are placed over plates 153 and 154, respectively,
with the aid of guidewire 156. A coupling device 151, which is
configured as a screw having lumen 161, is then advanced over
guidewire 156 and through lumens 162 and 165 of guide elements 152
and 155, respectively. Lumens 162 and 165 are preferably configured
to closely fit screw 151, which is also advanced through lumens 163
and 164 as well as opening 110. Lumen 165 of guide element 155 is
preferably threaded to lockingly receive screw 151.
[0143] Guide elements 152 and 155 are preferably configured to
allow angulation of screw 151 with respect to plates 153 and 154
when the components are routed over guidewire 156. In this
embodiment, guide elements 152 and 155 have a convex surface
configured to interface with a concave surface in each of plates
153 and 154, respectively, to permit variations in angulation,
which can occur due to the variability in anatomy of spinous
processes 14.
[0144] Alternatively, a variation of this embodiment can be used in
the gap between adjacent spinous processes such that plates 153 and
154 compress against both sides of either or both of the superior
and inferior spinous processes. Preferably, the width of coupling
device 151 is small enough that it does not contact the opposing
surfaces of the spinous processes above and below.
[0145] FIGS. 5H-L are perspective views depicting additional
example embodiments of attachment devices 201, where each
embodiment allows sleeve 101 and/or rod 102 (not shown) to be
positioned relatively closer to the spinous process. FIG. 5H
depicts an example embodiment of attachment device 201 configured
as a U-shaped clamp having an engagement feature 205 configured as
a raised portion 216 offset from spinous process 14 to create a
lumen therein. FIG. 5I depicts this embodiment with sleeve 101
contained beneath raised portion 216. FIG. 5J depicts a similar
embodiment, except that attachment device 201 has a plate-like
configuration and is fixed to spinous process 14 with screws 217-1
and 217-2. FIG. 5K depicts an example embodiment where raised
portion 216 only partially encompasses sleeve 101.
[0146] FIG. 5L depicts an example embodiment where attachment
device 201 includes an engagement feature 205 formed by a tether
538 routed through two iatrogenic openings 110-1 and 110-2 in the
spinous process 14. Each iatrogenic opening 110-1 and 110-2 is
lined by a grommet-like structure 539-1 and 539-2, respectively, to
allow for reduced friction as tether 538 passes therethrough.
Tether 538 can be a monofilament or a braided structure as shown
here. Tether 538 is preferably formed from a biocompatible material
including, but not limited to, nitinol, stainless steel, polymeric
materials, and the like.
[0147] FIGS. 6A-C depict another example embodiment of attachment
device 201, where an expandable rivet-like structure is used to
attach a plate-like base 234 to the spinous process 14. FIG. 6A is
a perspective view showing an example embodiment of expandable
rivet 228 having a central lumen 230 and a plurality of bent struts
229 extending out over plate-like base 234. FIGS. 6B-C are partial
cross-sectional views showing a method of deployment of this
embodiment of device 201.
[0148] An iatrogenic opening 110 in spinous process 14 is first
formed to allow passage of device 201 therethrough. Attachment
device 201 includes a second plate-like base 237 coupled with rivet
228 having a plurality of slots located therein, the portions of
rivet 228 between slots forming struts 229. A pull rod 231 is
placed within lumen 230 (not shown in FIGS. 6B-C). Pull rod 231 has
an enlarged portion 232 at its distal end to abut with rivet 228.
Plate-like base 234 has a lumen 235 and is placed over iatrogenic
opening 110 with rivet 228 routed therethrough. Pull rod 231 is
pulled proximally while applying a force on base 237 to maintain
the apparatus in place.
[0149] The result is shown in FIG. 6C, where the proximal force has
caused struts 229 to deflect outwards into a rivet-like
configuration and engage plate-like base 234, thereby coupling base
234 and base 237 to the opposing sides of spinous process 14. Pull
rod 231 can then be removed by advancing distally in a direction
opposite to direction 233. Although not shown in FIGS. 6B-C, each
base 234 and 237 preferably includes engagement feature 205 for
coupling to corrective system 100.
[0150] In another embodiment, pull rod 231 can be omitted and rivet
228 can be expanded by applying compressive force to both sides of
device 201 on process 14 with an externally located tool. In yet
another example embodiment, rivet-like structures 228 can be
coupled on both sides of the spinous process. It should also be
noted that this embodiment can be positioned in the space between
adjacent spinous processes.
[0151] FIGS. 7A-E depict additional example embodiments of an
attachment mechanism 201 for coupling with spinous process 14. FIG.
7A is a perspective view showing iatrogenic opening 110 through
spinous process 14. An inflatable member 240, such as a flexible
bag, balloon and the like, is provided with an optional inflation
port 241. Balloon 240 is threaded through opening 110 as depicted
in FIG. 7B. This can be performed manually or with the aid of a
guidewire routed through opening 110. An inflation medium is then
inserted into balloon 240 through inflation port 241. If no port is
provided, the inflation medium can be injected directly through the
wall of balloon 240. This inflation medium is preferably a cement
or resin or other liquid that will harden over time, although gels
and other viscous, semi-rigid, non-hardening materials can be used.
Examples of suitable hardening substances include, but are not
limited to, methyl-methacrylate (MMA), polymethyl methacrylate
(PMMA), epoxy resins, calcium phosphate, and the like.
[0152] Once inflated, balloon 240 forms anchor portions 242 and 243
on opposite sides of spinous process 14 as depicted in FIG. 7C.
These anchor portions 242 and 243 can then be relied upon as a
basis for coupling to spinous process 14. Balloon 240, among other
things, conforms to the surface profile of the spinous process 14,
distributing force evenly and eliminating or reducing the potential
of stress risers. FIGS. 7D-E are cross-sectional views depicting
two example embodiments of a through-rod 244 inserted through
opening 110 and balloon 240. Through-rod 244 preferably includes
engagement features on each opposing end to facilitate engagement
of spinal correction system 100 to spinous process 14. Here, the
engagement features of through-rod 244 are threaded portions 245 on
either end (as depicted in FIG. 7B) or enlarged portions 246 having
an eyelet (such as that depicted in FIG. 7E).
[0153] Through-rod 244 can be inserted into this configuration in
several ways. Balloon 240 can be provided with a through-aperture
(not shown) through which rod 244 can be inserted either before or
after curing of the resin. If a through-aperture is present, it can
also be used for threading balloon 240 through iatrogenic opening
110 prior to inflation. Alternatively, through-rod 244 can be
inserted through balloon 240 and the resin therein prior to full
curing of that resin. Or, after curing, a through-aperture can be
drilled by the user to create the opening in which to insert
through rod 244. Based on this description herein, one of skill in
the art will readily recognize that there are other methods of
inserting through-rod 244 that can also be used. Instead of
inserting through-rod 244 after inflation, balloon 240 can have
through-rod coupled thereto prior to threading through opening
110.
[0154] FIGS. 8A-B are cross-sectional views depicting another
example embodiment of attachment device 201, where attachment is
made by filling iatrogenic opening 110 with a cement or resin.
Preferably, this embodiment of device 201 includes a first side
plate 251 and a second side plate 252 configured to interface with
opposing sides of spinous process 14. Each plate 251 and 252
includes an internal chamber 253, which is preferably configured to
form an anchor once filled with the cement or resin. Here, chamber
253 has a width that is tapered or stepped to provide resistance to
detachment once filled with the cement or resin.
[0155] Plate 251 preferably includes an injection port 254 that
communicates with chamber 253-1. Chamber 253-1 has an open end that
is alignable with iatrogenic opening 110. Likewise, plate 252
includes an inner chamber 253-2 with an opening that is alignable
with iatrogenic opening 110. Plate 252 also includes one or more
(in this example, two) vent holes 255 that allow venting during
injection of the cement or resin. Both plates 251 and 252 can
include one or more engagement features 205 as well.
[0156] FIG. 8B depicts engagement device 201 after injection of
resin 256 into chamber 253-1, opening 110 and chamber 253-2 by an
injector 257. Injector 257 can then be removed. Plates 251 and 252
are preferably held in place until the cement or resin has cured
sufficiently to lock plates 251 and 252 in place on spinous process
14. Again, examples of cements or resins can include methyl
methacrylate (MMA), polymethyl methacrylate (PMMA), epoxy resins,
calcium phosphate, and the like.
[0157] FIG. 9 is a perspective view of another example embodiment
of attachment device 201 where the position of engagement feature
205 is adjustable. Here, adjustability is provided posteriorly and
anteriorly (up and down as depicted here), but superior and
inferior adjustment can also be provided as well as height
adjustment from the surface of spinous process 14. Attachment
device 201 includes a base 258 coupled with spinous process 14.
[0158] Base 258 preferably includes a housing 259 in which an
elongate member 260 is connected and allowed to slide both
posteriorly and anteriorly. Elongate member 260 includes an eyelet
261 for receiving rod 102 (not shown). It should be understood that
elongate structure 260 can take any configuration and be configured
to couple with any portion of corrective system 100, not limited to
rod 102.
[0159] Once properly positioned, elongate structure 260 is fastened
in place by a fastening device, such as set screw 264, which, in
this embodiment, is allowed to slide with structure 260 through
slot 263 in the side of housing 259. The ability to adjust position
in this manner is beneficial in that it allows for more precise
coupling of the spinal correction system 100 to the vertebral
bodies 11. Small changes in position can lead to the exertion of
large forces over the spinal column in the anterior and posterior
directions. These forces can be significant in the case of
segmental fixation, where every vertebral body in the treated
region is coupled directly with the spinal correction system 100.
These forces are generally undesirable since they are not
corrective and can lead to different spinal deformities and
potentially spinal stenosis. Thus, in these and other applications,
position adjustability can be highly desirable.
[0160] Alternatively, elongate structure 260 can be allowed to
freely slide (i.e., without fastening by set screw 264) according
to forces through natural motion of the spinal column. It should be
noted that base 258 can be configured and coupled with spinous
process 14 in any manner including each of those described herein
with respect to FIGS. 4A-8B and 10A-12B.
[0161] FIG. 10A is a perspective view depicting another example
embodiment of attachment device 201 where device 201 includes a
plate-like, base structure 248 having an engagement feature 205
located thereon. Base 248 is coupled with spinous process 14 by way
of a moldable material 249. Material 249 is preferably configured
to harden over time and can be methyl methacrylate (MMA),
polymethyl methacrylate (PMMA), epoxy resins, calcium phosphate,
and the like.
[0162] The use of moldable material 249 provides, among others, the
ability to manually form material 249 around base 248 to provide a
smooth, relatively atraumatic profile and limit any inflammatory
response by the body. FIG. 10B depicts base 248 after placement on
moldable material 249 and the forming, or molding, of material 249
around base 248 to provide a relatively atraumatic profile.
Moldable material 249 can also be fed or forced into one or more
iatrogenic recesses or through-openings in spinous process to
increase the anchoring with the spinous process.
[0163] It is also possible to configure attachment device 201 to
conform to the anatomy of the patient. For instance, FIGS. 11A-B
depict an example embodiment of attachment device 201 that has been
customized for a certain patient's spinous process 14. Here,
attachment device 201 has a U-shape (although it is not limited to
such) with first side 202 and second side 204 both having different
shaped configurations designed to complement and conform to the
features on the patient's spinous process 14.
[0164] FIG. 11A depicts attachment device 201 just prior to being
clamped on the spinous process 14, and FIG. 11B depicts attachment
device 201 after attachment. Mapping data as to the features of the
spinous process 14 can be obtained prior to surgery using any
visualization method (e.g., CT scans, MRI and the like). The data
can also be obtained during surgery using instruments such as a
laser profilometer. The mapping data can then be used to
manufacture portions 202 and 204 to complement the anatomy. The
mapping data can also be used to manufacture any portion of system
100 to fit the patient's anatomy in a customized fashion.
[0165] FIGS. 11C-D depict another example embodiment of attachment
device 201 where a compliant, or conforming, material 272 is
coupled to the inner surface of first portion 202 and second
portion 204. Compliant material 272 preferably conforms to the
shape of the patient's spinous process when attachment device 201
is attached (FIG. 11C depicts attachment device 201 prior to
attachment, and FIG. 11D depicts attachment device 201
post-attachment). Compliant material 272 can be formed from any
suitable material including, but not limited to, polymers, gels,
rubbers, elastics, silicones and the like.
[0166] FIG. 12A depicts an example embodiment of a compliant
toroidal element 273 having an inner aperture 274. Toroidal element
273 is preferably placed over spinous process 14 during attachment
of device 201 and acts, similar to material 272 described with
respect to FIGS. 11C-D, to conform to the features of spinous
process 14. Toroidal element 273 can be formed from a compliant
material such as those described with respect to FIGS. 11C-D, or
can be configured as a fillable structure (e.g., balloon, bag,
sheath and the like) that is placed between plate 275 (or 277) and
spinous process 14 and then filled with a biocompatible liquid or
gel, or a hardening resin such as epoxy or methyl methacrylate
(MMA).
[0167] FIG. 12B is a planar cross-sectional view showing attachment
device 201 in position over spinous process 14. Here, attachment
device 201 includes first and second toroidal elements 273-1 and
273-2 located between spinous process 14 and opposing plates 275
and 277, respectively. Plate 275 includes a threaded lumen 276 for
receiving a screw 279 which is inserted through lumen 278 in plate
277 and iatrogenic opening 110 in spinous process 14.
[0168] Based on the description provided herein, one of skill in
the art will readily recognize that the compliant elements (e.g.,
272 and 273) can be configured in other, non-toroidal manners to
allow conformance of attachment device 201 to spinous process 14.
Use of a moldable, compliant material allows for relatively
standardized rigid attachment structures to be used without the
need to pre-profile the patient's anatomy.
[0169] In addition to using prefabricated structures, attachment
device 201 (or any portion thereof) can be cast in place over
spinous process 14 during surgery. FIGS. 12C-D are perspective
views depicting an example embodiment of attachment device 201
during casting over spinous process 14. In FIG. 12C, a casting
device 287, having two molds 280 and 281 coupled with shafts 288
and 289, respectively, are placed on opposing sides of spinous
process 14 over an iatrogenic opening (not shown) extending
therebetween. Mold 280 includes an injection port 282 through which
the material to be cast is injected, and mold 281 preferably
includes a vent port 283 for venting during the injection of the
cement or resin. In an alternative embodiment, the cement or resin
can be injected into mold 280 through an inner lumen in shaft 288.
Venting can also occur through a lumen in shaft 289.
[0170] The inner surface of each mold 280 and 281 is shaped so as
to cast the desired attachment device configuration, an example of
which is depicted in FIG. 12D. Here, attachment device 201 includes
a plate-like base 284 with an elongate strut 285 extending
therefrom having an eyelet 286 through which a rod, sleeve spinal
coupling device or any other component of the spinal correction
system can be routed. A corresponding structure is preferably cast
on the opposing side, the two opposing structures being fastened to
each other and spinous process 14 by the presence of the resin or
cement within the iatrogenic opening (not shown) in spinous process
14.
[0171] Like the embodiments described with respect to FIGS. 7A-E,
the use of materials or configurations that conform to or match the
shape of the patient's spinous process, such as in the embodiments
described with respect to FIGS. 10-12D, provide for, among other
things, the distribution of force evenly across the engaged surface
and the elimination or reduction of the potential of stress
risers.
[0172] Numerous embodiments of attachment devices 201 have been
described, such as with respect to FIGS. 4A-12D. One of skill in
the art will readily recognize that the features of those
embodiments can be substituted for or combined with the features of
any other embodiment. For instance, various techniques and
configurations for attaching device 201 to the spinous process 14
are disclosed, and those techniques and/or configurations can be
used in place of or in combination with any other technique or
configuration disclosed.
[0173] As discussed earlier, provided herein are methods for
minimally invasive implantation of spinal correction systems within
the body of a patient. Preferably, the spinal correction system is
attached to a spinous process of a patient's vertebral body by
exposure of only the spinous process of that vertebral body,
although other variations of minimally invasive implantation
procedures have been described herein.
[0174] FIG. 13 is a flowchart depicting an example method of
implantation 400 of a spinal correction system in a minimally
invasive manner. In this embodiment, only the spinous process of
the vertebral bodies is exposed, but it should be noted that, in
other embodiments of this method, different amounts of the
vertebral body can be exposed, or tissue dissected therefrom,
including each of the variations of the minimally invasive methods
described herein.
[0175] At 401, an access opening is created in the skin of a
patient's back over the portion of the spinal column to be treated.
At 402, connective and surrounding tissue is removed from a
vertebral body of the patient, the tissue being removed such that
only a spinous process (or portion thereof) of the vertebral body
of the patient is exposed. At 403, an attachment device is coupled
with the exposed portion of the spinous process. The attachment
device is preferably configured to allow the transmission of a
corrective force from at least one elongate rod of the spinal
correction system to the patient's spinal column. At 404,
connective tissue can be removed from more vertebral bodies, if
desired, preferably occurring such that only the spinous process
(or a portion thereof) of the additional vertebral bodies is
exposed. Once exposed, at 405, other portions of the spinal
correction system can be coupled with those spinous processes. At
406, the implantation of the spinal correction system is completed
and, at 407, the access opening is closed.
[0176] In removing the connective tissue from the spinous process
of a patient's vertebral body, preferably, the medical professional
will first gain access to the supraspinous ligament and create an
incision through that ligament to gain access to the underlying
interspinous tissue. In this embodiment, any tissue connected with
the spinous process is then dissected from the spinous process,
taking care to avoid dissection from, at least, the anterior
portion of the flared transitional regions, and preferably the
entirety of the transitional regions. As noted above, preferably
the facet joints and the laminae are left unexposed as well. The
dissected tissue can include connective tissue such as the
interspinous ligament as well as surrounding muscular or fatty
tissue. The dissected tissue is pulled away to expose the spinous
process.
[0177] FIG. 14 is a flow diagram depicting another example method
410 of implantation of a spinal correction system. Here, the method
of implantation will be described with respect to implantation of
spinal correction system 100 described with respect to FIGS. 2A-B.
At 411, an incision is made through the skin of the patient's back
in the area generally centrally located along the portion of the
spinal column to be treated (e.g., a midpoint incision). At 412,
incisions are made at or over the spinous process of (preferably)
the uppermost and lowermost vertebral bodies of the patient's
spinal column to be treated. At 414, the tissue surrounding these
spinous processes are dissected to expose only the spinous process.
At 415, any desired attachment device (such as attachment devices
201 described herein) can be attached to these exposed spinous
processes.
[0178] At 416, an implantation space is preferably created between
the centrally-located incision and the uppermost incision. An
example of this is depicted in the perspective view of FIG. 15A,
where rod 102-1, contained within sleeves 101-1 and 101-3, is
advanced from centrally located incision 31, toward uppermost
incision 32 of the patient 30 to create a first implantation space
33-1 beneath the patient's skin. Implantation space 33 is depicted
as a raised portion of the patient's skin, although in practice a
raised appearance may not be present. Preferably, implantation
space 33 is created between each spinous process and the adjacent
interspinous tissue (e.g., the interspinous ligament). Accordingly,
spinous processes 14-3 and 14-4 are exposed through incision 31 to
allow access to implantation spaces 33.
[0179] The use of rod 102 or a similarly shaped instrument is
beneficial in that rod 102 is preferably shaped similarly to the
deformity of the patient's spinal column 10 and therefore is suited
to create implantation space 33 in the appropriate orientation and
shape. It should be noted that any shaped or unshaped instrument
can be used to create the implantation channel as desired for the
application.
[0180] Implantation space 33 is preferably created in a blunt
manner by advancing the distal end of rod 102-1 while within sleeve
101-1 along the spinal column 10 between each spinous process 14
and the adjacent interspinous ligament and other interspinous
tissue. The distal end of rod 102-1 and sheath 101-1 is preferably
relatively blunt in order to minimize the risk of inadvertently
damaging spinal column 10 or the tissue and ligaments adjacent
thereto. This advancement is continued until spinous process 14-1
of uppermost incision 32 is reached. One of skill in the art will
readily recognize that uppermost incision 32 (or the lowermost
incision) can be created before or after the rod is actually
advanced along spinal column 10.
[0181] At 418, implantation space 33-2 is created between incision
31 and lowermost incision 34, again, preferably by advancing rod
102-1 and sheath 101-3 in a blunt manner. This can occur in at
least several ways. First, as depicted in FIG. 15B, rod 102-1 is
bent in the midsection, and the opposite end is inserted from
central incision 31 toward incision 34. This is preferably possible
due to the high flexibility of rod 102-1. Alternatively, rod 102-1
can be composed of a biocompatible shape-memory material such as
nitinol, where it can first be cooled or chilled to allow it to be
easily deformed from its pre-curved shape to the bent configuration
depicted here. Once inserted into the body, rod 102-1 will warm to
the body's temperature and reenter the pre-curved
configuration.
[0182] In another example, rod 102-1 is advanced from central
incision 31 through implantation space 33-1 and through incision
32, until the opposing end of rod 102-1 is capable of being
inserted into central incision 31. At this point, rod 102-1 can
then be advanced from uppermost incision 32 past central incision
31 and along spinal column 10 until position appropriately within
lowermost incision 34, as depicted in FIG. 15C.
[0183] In yet another example, as described earlier, two (or more)
rod segments can be used instead of a single continuous rod. In
this embodiment, a first rod segment can be inserted from the
central incision 31 toward the uppermost incision 32, and a second
rod segment can be inserted from the central incision 31 toward the
lowermost incision 34. The rod segments can be inserted while
within sleeves 101, or sleeves 101 can be inserted first. These rod
segments can then be joined by a connector, such as rigid rod
connector 106 at central incision 31, which also preferably couples
the rod segments to the rod (or rod segments) on the opposing side
of the spinal column.
[0184] At 420, implantation spaces 33-3 and 33-4 are created for
the second rod 102-2. At 422, uppermost spinal coupling device
109-1 can be coupled with attachment device 201-1 and sleeves 101-1
and 101-2. The process can be repeated, and lowermost spinal
coupling device 109-2 can be coupled with attachment device 201-2
and sleeves 101-3 and 101-4. At 424, rod connector device 106 is
preferably coupled to rods 102-1 and 102-2. This can occur through
the interspinous ligament between adjacent spinous processes 14. In
this embodiment, coupling bands 108 are not used. This generally
final configuration of system 100 is depicted in FIG. 15D. At 426,
the dissected tissue can then be reattached to the extent desired
by the medical professional, and the incisions 31, 32 and 34 in the
patient's back can be closed.
[0185] It should be noted that numerous variances from the
above-described method can be implemented. For instance, although
the uppermost and lowermost spinous processes 14-1 and 14-2 are
shown to be adjacent to the ends of system 100, system 100 can
extend past these spinous processes further along the spinal
column. In addition, the order in which system 100 is implanted can
vary. For instance, instead of inserting rods 102 and sleeves 101
together to create the implantation spaces, another instrument can
be first used. That instrument can be configured to create both
implantation spaces for both rods at the same time. Sleeves 101 can
then be placed within the implantation space followed by rods 102.
Alternatively, rod 102 can be implanted first (with or without the
aid of another instrument) and used as a guide over which sleeves
101 can be inserted. In this example, the sleeves can be inserted
from the uppermost or lowermost incisions (or both in the case of
more than one sleeve).
[0186] In another embodiment, no direct coupling is made to the
spinal column at upper and lower positions. Only one incision is
required to be made, preferably a centrally located one from which
system 100 can be implanted. A rod connector 106 is then preferably
applied to connect rods 102, either through the interspinous
ligament itself, such that the device is essentially
"free-floating," or coupled directly to a spinous process.
[0187] In yet another embodiment, to create the implantation space,
a thin, flexible guide instrument is first inserted along the
spinal column. Sleeve 101 and rod 102 can then be attached to an
end of the guide instrument and pulled through the channel created
by the instrument to route sleeve 101 and rod 102
appropriately.
[0188] In a further embodiment, only lowermost and uppermost
incisions are made and the centrally located incision is foregone.
In such an embodiment, the rigid connection of rods using coupling
device 106 preferably occurs at least the uppermost or lowermost
incisions, if not both. This implantation method can prove
desirable with the implantation of shorter systems 100.
[0189] FIG. 16 is a flowchart depicting another example method 440
of implanting a spinal correction system 100, where the
implantation of one or more attachment devices 201 occurs with the
aid of a guidewire. An example embodiment of an attachment device
201 configured for implantation with the aid of a guidewire is
described with respect to FIG. 5G, although it should be noted that
this example method is not limited to such an embodiment of the
attachment device.
[0190] At 442, the medical professional inserts a guidewire through
a percutaneous opening in the patient's back (created by the
guidewire or another instrument), in a lateral direction entirely
through a first spinous process to create an iatrogenic opening.
This can be accomplished with a guidewire having a sharp tip, such
as a Kirschner wire (K-wire), or with another piercing instrument.
Imaging, such as fluoroscopy, is also preferably employed to aid
the physician in piercing the spinous process in the desired
location. At 444, the guidewire is preferably passed through a
second opening in the patient's back on the opposing side.
[0191] At 446, the size of the iatrogenic opening can be expanded
appropriately. This can be accomplished by the iterative
application of one or more dilators, each being larger than the
previous dilator (or the guidewire). At 448, the attachment device
is preferably routed over the guidewire and into place on (one or
both sides of) the spinous process.
[0192] For instance, if using an embodiment similar to that
described with respect to FIG. 5G, the attachment device 201 is
placed sequentially on both sides of spinous process 14 starting
with the opposing base plates 153 and 154, each advanced into
position over guidewire 156 from the opening in the patient's back
on each respective side of spinous process 14. It should be noted
that the openings through the skin and tissue (e.g., fascia) to
spinous process 14 can be sized corresponding to the largest
portion of the attachment device 201 that must be advanced
therethrough, thereby allowing the size of these openings to be
minimized. Guide elements 152 and 155 are also advanced into place
over guidewire 156 and into position over each base plate 153 and
154, after which screw 151 is advanced and used to couple the
components together.
[0193] At 450, the guidewire can be removed. Then, at 452, the
medical professional can advance the portion of the spinal
correction system to be attached to the attachment device into
proximity with the attachment device such that it can be coupled
thereto. For instance, the medical professional can advance a rod
(or sleeve, or rod and sleeve, etc.) through a separate opening in
the patient's back and into proximity with the attachment
device.
[0194] At 454, the medical professional couples the attachment
device with the desired portion of the spinal correction system.
For instance, in one embodiment the attachment device includes an
eyelet or other housing for receiving the rod, and the rod can be
routed directly through the eyelet to couple the two together,
thereby requiring minimal access (and a minimal opening) for the
medical professional through the laterally placed openings in the
patient's back. Depending on the level of user access needed to
couple the rod or component with the attachment device, the opening
through which the attachment device is inserted can also be
minimized. Also, the opening through which the rod or other
component of the spinal correction system is inserted can be sized
minimally, generally the same as that rod or component. After
completion of the implantation of the spinal correction system,
which may include the implantation of multiple attachment devices,
then at 456, the medical professional closes the various openings
in the patient's back.
[0195] Of course, if desired, a single incision can be placed along
the length of the spinal column where system 100 is to be
implanted, to expose the entire implantation space. This can allow
for other configurations of system 100 to be implanted. FIG. 17 is
a lateral view depicting another example embodiment of spinal
correction system 100. Here, system 100 is configured to be
implanted along the edges of the posterior side 27 of one or more
spinous processes 14. Multiple attachment devices 201 are coupled
on each spinous process 14 to be treated, and include a tubular
portion configured to hold a rod 102. This embodiment provides the
benefit of restricting exposure of spinous processes 14 to only the
most posterior portion (e.g., less than 50% of the length of each
spinous process 14).
[0196] Any portion of system 100 can be coated with any material as
desired. Some example coatings that can be used include coatings
that are biodegradable, drug coatings (e.g., drugs can be released
from hydrogels or polymer carriers where the polymer itself is a
biodegradable material or elastomer, coatings that increase or
decrease lubricity, bioactive coatings, coatings that inhibit
thrombus formation, and coatings that speed the healing
response.
[0197] These coatings can be applied over the entire system 100 or
any portion thereof. Also, different portions of system 100 can be
coated with different substances. Furthermore, the surface
topography of the elements of system 100 can be varied or
configured to accelerate biodegradation of those elements (if
including biodegradable materials) and/or to promote tissue
encapsulation thereof.
[0198] FIG. 18 is a side view of a spinal column having another
example embodiment of a corrective treatment system 100 attached
thereto. This treatment system can be implanted with any of the
methods of implantation described herein. In this embodiment,
treatment system 100 includes rod 102 and three engagement devices
(or connectors) 301, 320-1 and 320-2 that couple rod 102 to
selected individual spinous processes 14 of the patient's spinal
column 10. Alternatively, system 100 can be connected to the
pedicles. Here, a connector 301 of a first type is coupled with
spinous process 14 of the L1 vertebral body and connectors 320-1
and 320-2 of a second type are coupled with the superiorly located
T9 vertebral body and the inferiorly located L5 vertebral body.
These locations are merely examples and it should be understood
that the number and placement of connectors 301 and 320 are
dependent on the condition of the patient and desired treatment
plan set forth by the administering medical professional.
[0199] Connector 301 is preferably secured to a spinous process 14
and configured to permit certain limited movement of rod 102 in
relation to connector 301 (and the vertebral body to which it is
connected). Preferably, connector 301 limits the degree to which
rod 102 can translate (or slide) longitudinally along the patient's
spinal column, i.e., in the inferior and superior directions, and
substantially prevents rod 102 from rotating about its longitudinal
axis. For this reason, connector 301 will be referred to herein as
a "fixed" connector, although connector 301 does allow rod 102 to
pivot (or tilt) in certain directions as will be explained in more
detail herein.
[0200] Connectors 320 are also preferably configured to allow rod
102 to pivot and rotate in certain directions, but connectors 320
also preferably allow rod 102 to translate (or slide)
longitudinally along the patient's spinal column. For this reason,
connector 320 will be referred to herein as a "slidable" connector.
Connectors 301 and 320 can also be referred to as housings,
retainers, fixation points or couplings.
[0201] In a preferred embodiment, at least one fixed connector 301
is present to limit the translation of rod 102 with respect to the
spinal column. However, if desired, more than one fixed connector
301 can be used at any point along the length of rod 102. In this
embodiment, two slidable connectors 320 are located at each end of
rod 102 to retain rod 102 in proper alignment with the spinal
column, however, any desired number of one or more slidable
connectors 320 can be placed at any vertebral body in the region to
be treated. If one slidable connector 320 and one fixed connector
301 are used, preferably they are placed on opposite ends of rod
102.
[0202] FIG. 19A is a perspective view depicting an example
embodiment of fixed connector 301 with rod 102 coupled thereto.
Here, rod 102 is fixed to an axle member 302 that extends on
opposite sides of rod 102 and interfaces with the fixed connector
301. Axle member can be coupled with the rod in any manner that
prevents rotation of rod 102 with respect to axle member 302
including, but not limited to, an interference fit, welding,
soldering, adhesives, clamps and the like. Preferably, axle member
302 has a through-lumen to receive rod 102 and is coupled with rod
102 using a press fit, such as a cryo-fit. Alternatively, axle
member 302 can be an integral part of the rod, e.g., the rod and
axle member are of uni-body construction. One such method of
manufacturing a uni-body construction can be grinding or otherwise
removing excess material from a larger piece of material to form
the desired diameter rod with one or more elongate projections that
act as the axle member.
[0203] Fixed connector 301 includes an inner housing 303 and an
outer housing 304, which together form two lumens 305 and 306 in
which rod 102 and axle member 302 are housed, respectively. Lumens
305 and 306 are preferably oversized to allow specific types of
movement by rod 102 and axle member 302. For example, fixed
connector 301 is configured to allow rod 102 to pivot within lumen
305 in the coronal plane of the vertebral body (indicated as the
X-Y plane) and to allow axle member 302 to pivot within lumen 306
in the sagittal plane (indicated as the X-Z plane). Fixed connector
301 is configured to allow a limited amount of longitudinal
translation. In this embodiment, the translation is limited to the
difference between the superior-to-inferior length of lumen 306 and
the diameter of axle member 302. Fixed connector 301 is also
configured to prevent rod 102 from substantial rotation about its
longitudinal axis 190. A negligible degree of rotation is possible
due to manufacturing tolerances and the like. By allowing pivoting
of rod 102 in the coronal and sagittal planes, fixed connector 301
is configured to alleviate, or at least reduce, any moments created
in those planes through movement of the patient. This can reduce
lateral and rotational stresses placed on spinous process 14.
Limiting the ability of rod 102 to rotate about its longitudinal
axis helps maintain the predetermined corrective shape of rod 102
in the proper radial alignment to apply a properly directed
corrective force (i.e., so as not to "correct" natural proper
curvature of the spine).
[0204] FIG. 19B is a side view of fixed connector 301 showing rod
102 therein. Rod 102 has the freedom to pivot or pivot about axle
member 302 in the coronal plane. Lumen 305 is preferably larger
than the diameter of rod 102 and sized and shaped to permit and not
obstruct the preferred range of motion for rod 102. Also shown are
engagement features 330, which in this embodiment are configured as
conical abutments or spikes that protrude from the base surface 341
of inner housing 303 and can be capable of acting as a bone anchor
to facilitate the securement of connector 301 to the spinous
process. These engagement features 330 will be discussed in more
detail herein.
[0205] FIG. 19C is a top-down view of fixed connector 301 with rod
102 housed therein and pivoted in the coronal and sagittal planes.
This pivoting occurs about axes that intersect rod 102, and thus
allow for efficient alleviation or reduction of moments on the
underlying vertebral body. Here, pivoting in the coronal plane
occurs about axis 377, which is the longitudinal axis of axle
member 302 and intersects rod 102. Pivoting in the sagittal plane
occurs about axis 378 (shown here as normal to FIG. 19C), which
intersects rod 102 at axle member 302.
[0206] Outer housing 304 includes upper and lower U-shaped or
concave recesses 307, which allow rod 102 to pivot as shown in FIG.
19B. The depth to which recesses 307 extend from the sides of
connector 301 can, at least partially, determine the degree to
which rod 102 can pivot in the coronal plane. Likewise, the width
of recesses 307 can, at least partially, determine the degree to
which rod 102 can pivot in the sagittal plane while simultaneously
pivoting in the coronal plane. The degree of pivoting in the
sagittal plane can also be determined by the shape of lumen 306 as
described below.
[0207] Referring back to FIG. 19A, the inner base surface of inner
housing 303 is tapered in region 308 to allow even greater freedom
to pivot in the coronal plane. FIG. 19B shows lumen 306 with axle
member 302 housed therein. Here, it can be seen that lumen 306
allows axle member 302 to rotate in the coronal plane. Lumen 306 is
oversized along the X-axis but has a width similar to the diameter
of axle 302 along the Z-axis. This allows limited pivoting of rod
102 in the sagittal plane while at the same time restricting the
rotation of rod 102 about its longitudinal axis. This also allows
rod 102 to slide by a limited amount along the X-axis.
[0208] As noted herein, system 100 can include a rod 102 or other
corrective device positioned on one or both sides of the patient's
spinous processes. The following figures describe an example
embodiment of system 100 where two separate rods are used, each
being positioned on a separate side of the patient's spinal
column.
[0209] FIG. 19D is a perspective view depicting an example
embodiment of inner housing 303-1, which is preferably configured
for placement on a first side of the patient's spinous process.
FIG. 19E is a perspective view depicting a second inner housing
303-2 configured for placement on the opposite side of the
patient's spinous process Inner housings 303-1 and 303-2 can each
be coupled with the spinous process separately or, as depicted
here, can be configured to couple together through one or more
surgically created lumens in the patient's spinous process Inner
housing 303-1 includes a through-hole 309 through which a retaining
element (not shown), such as a threaded bolt, can be placed. The
threaded bolt is preferably inserted into through-hole 309 and then
through the lumen in the patient's spinous process. The threaded
end of the retaining element is preferably screwed into a threaded
lumen 315 in the opposing inner housing 303-2 as shown in FIG. 19E.
The retaining element preferably has a retaining head larger than
through-hole 309 such as to reside in recess 314 and retain inner
housing 303-1. One of skill in the art will readily recognize that
multiple different types of retaining elements can be used
including but not limited to clamps, screws and the like.
[0210] It should be noted that through-hole 309 and threaded lumen
315 are preferably centrally located on inner housings 303-1 and
303-2. If multiple retaining devices are used, then the
corresponding apertures within inner housings 303 are preferably
positioned symmetrically. Configuration in these manners allows the
retaining force to be uniformly applied over the inner housing and
reduces the risk that a non-uniformly applied retaining force will
allow housing 303 to become dislodged in the region where the
retaining force is weakest.
[0211] If only one rod is used in system 100, then inner housing
303-1 can be coupled only to the spinous process and not an
opposing inner housing. Regardless of the number of housings, each
can be coupled to the spinous process in any desired manner
including, but not limited to, the manners of those other
embodiments described with respect to FIGS. 4A-12D herein.
[0212] Inner housings 303-1 and 303-2 each have a generally
platelike base from which four projections or projecting segments
extend, generally at each of the four corners of the plate. Each
inner housing 303 is preferably sized and configured according to
the dimensions of the vertebral body to which it is intended to be
attached. The underside of the planar base can be coated with a
cushioning material or a material designed to conform to the
surface texture of the spinous process. Each projection 311
includes a lumen 310, which is preferably used for coupling with
outer housing 304 (not shown in FIGS. 19D-E). As shown here, a
U-shaped, parabolic, or semicylindrical, recess 313 is positioned
laterally on opposite sides of inner housing 303 and form the lower
portion of lumen 306 through which axle member 302 is routed.
[0213] Spaced regions, or recesses, 319-1 and 319-2, which are
shown on the superior and inferior sides of inner housing 303-1 and
303-2, together form the lower portion of rod lumen 305.
Projections 311 each have a tapered surface 312 adjacent recess 319
that promotes pivoting of rod 102 (not shown) within lumen 305.
These tapered surfaces 312 are positioned near the periphery of
housing 303 and the degree to which surfaces 312 taper can, in
part, be used to adjust the desired amount of pivoting of rod 102.
Also shown here are tapered inner base surfaces 308-1 and 308-2
within recesses 319-1 and 319-2, respectively, which facilitate
pivoting of rod 102 in the coronal plane as previously
described.
[0214] FIGS. 19F-G are perspective views of outer housing 304,
which can be used with either embodiment of inner housing 303-1 and
303-2. Here, outer housing 304 includes a generally platelike base
portion with four projections 317 extending generally from the four
corners of the housing 304. The projections 317 and upper interior
surface of housing 304 together define the upper portion of lumen
305. Each projection 317 includes a lumen 316, which can be used to
receive a retaining device to couple outer housing 304 with either
of inner housings 303-1 and 303-2. For instance, lumen 310 can be
threaded and a screw-like or bolt-like retaining device can be
inserted through lumen 316 and into the corresponding lumen 310 of
inner housing 303 in order to screw the housings 303 and 304
together. One of skill in the art will readily recognize that many
different manners of attachment can be used to couple housings 303
and 304 together including, but not limited to, clamps, snaps,
clips, adhesives and the like. Similar to inner housing 303, outer
housing 304 also includes an inner tapered surface 318, which can
match the tapered surface 312 on inner housing 303. Outer housing
304 also includes U-shaped, parabolic or semicylindrical recesses
307-1 and 307-2. Also, outer housing 304 includes lateral U-shaped
or semicylindrical recesses 348-1 and 348-2, which end beneath the
upper surface of housing 304 and form the upper portion of axle
lumen 306.
[0215] FIG. 20A is a perspective view depicting an example
embodiment of slidable connector 320 coupled with a spinous process
14 and having rod 102 routed therethrough. Here, slidable connector
320 includes an inner housing 321 and an outer housing 322 with a
tubular housing, or bushing 323, coupled between both housings
Inner housing 321 includes a base portion 331 and a bushing support
portion 332. Inner housing 321 and outer housing 322 are connected
together with retaining devices (not shown) routed through lumens
324-1 and 324-2 of outer housing 322 and corresponding lumens (not
shown) in inner housing 321. As described above, the retaining
device can be, for instance, configured as a screw that is received
within a threaded lumen in inner housing 321. Bushing 323 includes
an inner lumen 336 having sloped surfaces that permit rod 102 to
pivot therein. Here, the sloped surface 325-1 present on the near
side of bushing 323 is shown. Bushing 323 also includes enlarged
diameter portions 338-1 and 338-2, which will be described in more
detail herein.
[0216] FIG. 20B is a side view of slidable connector 320 with rod
102 routed through lumen 336. As can be seen here, the diameter of
rod 102 is preferably undersized with respect to the inner diameter
of lumen 336. This intervening free space, in combination with
sloped surfaces 325, allows rod 102 to pivot in the coronal and
sagittal planes. It allows rod 102 to rotate about its longitudinal
axis, although this rotation is limited by fixed connector 301
(and/or limitations to the range of motion of the patient). This
free space also allows rod 102 to move laterally, e.g.,
side-to-side translation, in the coronal plane, by a limited
degree. In addition, this free space reduces the friction between
rod 102 and the inner surface of bushing 323, facilitating the ease
to which rod 102 can slide longitudinally through lumen 336. This
can improve the patient's mobility and can also facilitate initial
implantation of the rod and/or system itself. Additionally, this
can provide the advantage of reducing the risk that the rod will
become seized, caught or otherwise stuck in the slidable connector,
which can result in the loading of undesired moments on the spinous
process(es).
[0217] Sloped surfaces 325 are shown in greater detail in the
perspective view of bushing 323 depicted in FIG. 20H and in the
longitudinal cross section of FIG. 20I. Here, it can be seen that
lumen 336 includes a first sloped surface 325-1 that extends from a
first end 387 of bushing 323 toward the center of bushing 323, such
that lumen 336 decreases in diameter. An intermediate surface 340
is present in the central region of lumen 336 and has a generally
flat, unsloped surface. On the opposite side of bushing 323 is a
second sloped surface 325-2 that slopes from end 388 toward
intermediate surface 340 such that lumen 336 decreases in diameter.
The degree to which surfaces 325 slope, as well as the extent to
which the diameters of rod 102 and lumen 336 differ, determine the
degree to which rod 102 can pivot within slidable connector
320.
[0218] Although rod 102 can preferably freely rotate within lumen
336, slidable connector 320 and/or rod 102 can be configured, if
desired, to prevent or limit such rotation. For instance, rod 102
can have a fixed longitudinal feature that interfaces with a
complementary feature in slidable connector 320 that prevents rod
102 from rotating. It should be considered that prevention of all
rotation with respect to the slidable connector would load the
spinous process with a moment, which can be undesirable.
[0219] Bushing 323 formed or coated with a lubricious polymeric
material, such as PEEK and the like, or a polymer impregnated with
lubricious material, such as tetrafluoroethylene (TFE) and the
like. Bushing 323 can also be formed from ceramic materials. If
coated, bushing 323 can be formed from any rigid material such as
nitinol, stainless steel, titanium, elgiloy and the like. Other
coatings can include diamond-based coatings, titanium nitride and
the like. The surface of bushing 323 can also be treated to reduce
friction, such as by electro-polishing. These coatings and surface
treatments can likewise be applied to rod 102.
[0220] Bushing 323 is preferably held in a secure manner between
inner and outer housings 321 and 322 by enlarged diameter portions
338-1 and 338-2. An intermediate portion 339 of bushing 323, having
a smaller diameter than portions 338, is configured to be received
within recesses of inner and outer housings 321 and 322. FIG. 20C
is a perspective view depicting an example embodiment of outer
housing 322. Shown here is semicircular recess 326, which is
configured to receive the intermediate portion 339 of bushing 323.
Recess 326 can have any shape suitable to retain bushing 323.
[0221] FIG. 20D is a perspective view of inner housing 321 with
base 331 and bushing support portion 332. Base 331 can have flared
edges to provide an atraumatic interface with the surrounding
tissue Inner housing 321 includes a threaded lumen 329 configured
to receive a retainer device in a manner similar to that described
with respect to fixed connector 301. The retainer device can couple
directly to the spinous process 14 or to another inner housing 321
located on the opposite side of the spinous process. Also shown
here is semicircular recess 328, which is configured to align with
semicircular recess 326 of outer housing 322 to form a channel in
which intermediate portion 339 of bushing 323 can be retained. Also
shown are lumens 327-1 and 327-2, which preferably align with the
corresponding lumens 324 in outer housing 322. Lumens 327-1 and
327-2 are preferably threaded to accept a screw or other retainer
inserted through lumen 324.
[0222] FIG. 20E is a perspective view of the underside of inner
housing 321. Underside surface 337 includes multiple engagement
features, configured here as bone anchors 330-1 through 330-4. Each
bone anchor, in this embodiment, is configured as a conical
abutment, or spike, and is configured to be inserted into the
spinous process to facilitate the anchoring and securement of inner
housing 321 thereto.
[0223] FIG. 20F is a perspective view of an example embodiment of a
second inner housing 321 for slidable connector 320, for use in an
embodiment where two slidable connectors 320 are coupled to
opposite sides of a single spinous process. This embodiment is
generally similar to that described with respect to FIGS. 20D-E,
with the exception that a through-hole 333 is present instead of a
threaded lumen. Through-hole 333 can receive, for example, the head
of a retaining device such as a screw that is retained by the
sloped surfaces of through-hole 333 such that the retainer can
securely couple with this inner housing and extend through a
surgically created opening in the spinous process to the opposite
inner housing. Also shown here is semicircular recess 334, which
includes an optional cutaway portion configured to accommodate the
head of the retaining device.
[0224] FIG. 20G is a side view of the example embodiments of inner
housing 321 described with respect to FIGS. 20D-F positioned
opposite each other in a manner suitable for attachment to the
spinous process. Here, inner housing 321-1 corresponds to that
described with respect to FIGS. 20D-E, and inner housing 321-2
corresponds to that described with respect to FIG. 20F. It can be
seen that bone anchors 330 on inner housing 321-1 and bone anchors
335 on inner housing 321-2 are offset from each other so as to
evenly distribute the force applied by the anchors onto the spinous
process. This can minimize the risk that the spinous process will
fracture. Here, bone anchors 330-1 and 330-2 are two of the four
bone anchors that are visible (see FIG. 20E). Each bone anchor 330
and 335 is preferably located equidistant from each other bone
anchor on the same housing. Also, the bone anchors on one inner
housing are preferably positioned to achieve the maximum offset
from the points of contact of the bone anchors on the opposite
inner housing.
[0225] For instance, bone anchors 330 on inner housing 321-1 are
located near the outer edge of the underside surface and at
90-degree radial intervals (i.e., 45 degrees, 135 degrees, 225
degrees and 315 degrees about the periphery of inner housing
321-1). Bone anchors 335 are also preferably positioned near the
outer edge of the underside surface and at 90-degree radial
intervals, but offset by 45 degrees from the bone anchors 330
(i.e., bone anchors 335 are at 0 degrees, 90 degrees, 180 degrees
and 270 degrees about the periphery of inner housing 321-2). Of
course, the spacing and arrangement is dependent upon the number
and size of the anchors. Other nonuniform or asymmetric
configurations can also be used depending on the needs of the
application and/or the structure of the bone anchor or equivalent
feature. It should be noted that a textured surface can be used
instead of discrete bone anchors 330 and 335. That textured surface
can extend about the entirety of or any portion of the underside
surface 337 of each inner housing.
[0226] The embodiments of the fixed and slidable connectors 301 and
320 described herein generally include an inner and outer housing
where the outer housing is described as connecting to the inner
housing from a lateral (e.g., left-to-right, right-to-left)
direction. Lateral attachment requires the surgeon to have
relatively more access to the lateral side of the spinous process,
which requires relatively more invasive surgery. Alternatively,
each of these embodiments can be configured such that the outer
housing connects to the inner housing from a posterior-to-anterior
direction. Attachment of housing 343 to housing 342 in the
posterior-to-anterior direction allows the surgeon (or other
medical professional) to create a smaller surgical cavity around
the spinous process since the surgeon is not required to position
and attach the housings together laterally.
[0227] FIG. 21 is a perspective view of an example embodiment of
fixed connector 301 coupled with spinous process 14. Here, fixed
connector 301 includes an inner/lower housing 342 and an
outer/upper housing 343 that is configured to be coupled with lower
housing 342 in the posterior-to-anterior direction indicated here
by the arrows. Multiple lumens 344-1 through 344-3 are present to
accept a retaining device that couples with the inner edge plate
345 of lower housing 342. Similar lumens 346-1 and 346-2 are
present on the opposite side of the device and are configured to
allow a retaining device to couple with outer plate 347 of inner
housing 342. Similar to the embodiments described previously, a
suitable retaining device in this example can be a threaded screw
or a bolt, although one of the skill in the art will readily
recognize that other retaining devices can be used.
[0228] The embodiments described with respect to FIGS. 18-21
provide the advantage of allowing the rod (or other corrective
device) to move with respect to the spinous processes to alleviate
any moments that are created on the spinous processes as a result
of the patient's movement, iterative correction caused by the
device, or even during implantation. Because these embodiments
guide the motion of the rod itself, and preferably do not rely on
an intermediate moving device or mechanism to allow for motion, and
move with the rod, the efficiency of the system is greatly
enhanced. The elimination of any intermediate (or intervening)
moving part increases the efficiency and reliability of the system
and allows the system to achieve an overall lower profile, which
can translate into less discomfort to the patient and can require
less invasive surgery during implantation. Alternatively, the axle
member can be integrated directly into the connector such that the
axle member may be considered a moving part of the connector, with
the rod coupled to the axle member. In such an instance, the axle
member is shared between the rod and the connector. Nevertheless,
some or all of the advantages of these embodiments persist (e.g.,
as compared to Rivard U.S. Pat. No. 6,554,831). The operation and
configuration of the system can remain substantially the same, and
the system can still achieve an overall lower profile with
increased reliability.
[0229] These embodiments relieve moments centered (or focused)
about the rod itself, as opposed to introducing a fixed
intermediate connector to the rod and attempting to relieve moments
around that intermediate connector (see, e.g., Rivard U.S. Pat. No.
6,554,831). For instance, the slidable connector can allow the rod
to directly pivot a limited amount in the coronal plane as opposed
to pivoting about the end of an intermediate connector. Also, the
fixed connector can allow pivoting of the rod in both the coronal
and sagittal planes around the rod itself, as opposed to the end of
an intermediate connector.
[0230] FIGS. 22A-K depict example embodiments of a link-based
correction system 350. System 350 preferably includes a plurality
of links that interface with one or more adjacent links to provide
limited freedom of motion in the sagittal plane while at the same
time restricting motion and applying corrective force in the
coronal plane. FIGS. 22A-C are side views depicting a first example
embodiment of system 350. Here, system 350 includes multiple outer
links 351 (only one shown) each coupled to one or more inner links
352. Outer link 351 preferably includes a longitudinal slot 353 in
which an elongate guide element (e.g., a pin) 354 can be placed.
Guide element 354 is preferably routed through both outer link 351
and inner link 352-1, so as to couple the two links together and
serve as an axle for limited pivoting motion and as a guide for
translational motion through slot 353-1. Guide element 354
preferably has an enlarged head to retain element 354 with respect
to links 351 and 352. A similar arrangement is present with slots
355 and guide elements 356, which are used to couple inner link
352-1 with a second adjacent outer link 351 (not shown).
[0231] FIG. 22D is a top-down view of this chain-like system 350
showing outer links 351 coupled to inner links 352 by guide
elements 354. Here, outer links 351 include two plates 357 and 358
and, likewise, inner links 352 include two plates 359 and 360. Each
plate is preferably polygonal with rounded edges and, when viewed
from the perspective of being coupled alongside a spinous process,
generally has a length (measured superiorly inferiorly) that is
greater than a width (measured posteriorly anteriorly), which, in
turn, is greater than a thickness (measured laterally). The plates
202 and 204 can also be described as planar members, elongate
members or strut-like members. In this and the other embodiments of
link-based systems described herein, relatively short rods can be
used instead of plates.
[0232] Guide element 354 preferably includes enlarged head portions
380-1 and 380-2 located on the exterior surfaces of plates 357-1
and 358-1, respectively. Guide element 354 also preferably includes
an elongate shaft extending between head portions 380. Shaft 381
preferably has a relatively wider central section that retains the
opposing plates of links 351 and 352 in spaced relation to each
other. Alternatively, a central strut can be positioned between
plates 357 and 358 (or 359 and 360) to maintain those plates in
spaced relation to each other. Also, only one plate can be used
provided that the plate is sufficiently rigid to exert the desired
amount of corrective force in the coronal plane. The guide element
354 can also be routed through a similar longitudinal slot in inner
link 352 if desired, or, inner link 352 can include a round
aperture for holding the guide element 354 in a relatively fixed
position with relation thereto.
[0233] Here, outer link 351-3 is shown coupled with an adjacent
spinous process 14. Only one such coupling is shown here although
it should be noted that any number of one or more outer links 351
can be coupled with the adjacent spinous processes 14. An aperture
383 is surgically created in spinous process 14 in which a
retaining (or engagement) device 386 can be routed. Retaining
device 386 is configured as a threaded bolt 390 with an enlarged
head 389. The threaded bolt 390 is coupled with an opposing nut 382
after bolt 390 is routed through the aperture 383 in the spinous
process 14, an optional annular spacer 384 and a through-hole 385
in plate 357-3. Alternatively, system 350 can be coupled directly
to another system 350 located on the opposite side of spinous
process 14.
[0234] Referring back to FIG. 22A, outer links 351 are each
preferably connected to an individual spinous process 14 with inner
links 352 extending therebetween. The patient can have separate
systems 350 implanted on either side of the spinal column or only
one system 350 can be used. Also, instead of implanting system 350
on a single side of the spinal column, system 350 can be coupled
directly on top of the spinous processes of the patient's spinal
column. For instance, although not shown here, outer link 351 can
be enlarged to fit on top of a spinous process 14 with sufficient
room to allow movement of inner link 352 in relation thereto. Outer
link 351 can then be secured to the spinous process in much the
same way as described with respect to FIG. 22D below, or with
respect to other embodiments discussed herein.
[0235] System 350 is preferably configured to allow translational
movement between each link such that system 350 can expand and
contract longitudinally, e.g., superiorly-inferiorly. FIG. 22A
depicts system 350 in a generally expanded state, and FIG. 22B
depicts system 350 in a contracted state where the ends of system
350 have been retracted toward each other as indicated by the
arrows. Each link 351 can rotate about guide element 354 with
respect to each adjacent link 352, allowing system 350 to bend in
sagittal plane as needed. System 350 can also be configured to
allow some twisting (e.g., between adjacent links) to follow a
twist in the spine. FIG. 22C depicts an exaggerated view of system
350 coupled to a patient's spinal column 10 while that spinal
column 10 is in a state of flexion. As can be seen here, the
ability of system 350 to bend and to expand and contract
longitudinally allows significant freedom of movement for the
patient during flexion, and likewise during extension. The rigidity
of system 350 in the coronal plane and the flexibility of system
350 in the sagittal plane allows the patient greater mobility while
continuing to apply the desired corrective force. Preferably, the
links are made of a bendable elastic material (e.g., polymeric
materials, stainless steel) or superelastic material (e.g., a NiTi
alloy such as nitinol), such that any deformation of the links in
the coronal plane enacts a return force that can be used to correct
the deformity. Alternatively, the links can be made fully rigid,
such that there is no flexibility in the coronal plane.
[0236] FIGS. 22E-G depict additional example embodiments of a
link-based corrective system 350. In the embodiment of FIGS. 22E-F,
system 350 is positioned over the spinous processes 14 such that
each spinous process 14 lies between an opposing pair of linkage
plates 357-358 or 359-360. Similar to the previous embodiment,
system 350 includes outer links 351 and inner links 352. Each inner
link 352 is coupled to one or more adjacent outer links 351 by an
elongate guide element 391 that is configured here as an axle and
is inserted through apertures and/or slots (such as those depicted
in FIG. 22G) in both plates 357/358 of outer link 351 and plates
359/360 of inner link 352. Preferably, guide element 391 resides in
at least one longitudinal slot present in both sides of the system
(i.e., one slot in at least one of the outer plate and inner plate
on both the left and right sides). The guide element can slide
along the longitudinal slot allowing the links 351 and 352 to pivot
laterally (in the coronal plane) and elongate to allow flexion and
extension of the spine.
[0237] A spacer 396 is positioned over guide element 391 and
located between the inner plates 359 and 360. Spacer 396 is
preferably configured to match the width of the adjacent spinous
processes 14 such that the plates are held in close proximity to,
or in contact with, the respective spinous process. The spacer
could be made from a metal alloy such as stainless steel or
titanium alloy. It could also be made from a plastic such as PEEK
or UHMWPE. Preferably, the spacer is substantially rigid to prevent
the plates from applying excessive lateral force on the spinous
processes. Spacer can be separate or integrated with guide
element.
[0238] Guide element 391 preferably includes a retaining element
392/393 on each end. Between each retaining element 392/393 and the
adjacent plate 357/358 is positioned a bias element 394/395,
respectively. The bias element 394/395 is shown here to be in the
form of a coil spring capable of exerting an expansive force
between the retaining element 392/393 and the respective adjacent
plate 357/358 (or 359/360). The coil spring is preferably conical
to allow the spring to achieve a lower profile upon collapse. It
should be noted that the type of bias element used can be varied
depending on the needs of the application. For instance, elastic
cylindrical members, multiple coils, expansive clips, leaf springs
and the like, can all be used instead of a spring-like member. The
bias element can also be integral to the guide element 391.
[0239] FIG. 22E depicts system 350 in position over a relatively
healthy portion of spinal column 10, for instance after the spinal
defect has been corrected. FIG. 22F depicts system 350 in position
over a defective spinal column upon implantation or during
treatment. Here, spinous process 14-2 is part of a vertebral body
that is deflected with respect to the adjacent vertebral body, and
this deflection is corrected by the use of system 350. Springs
394-1 and 395-1 create a compressive force against plates 357-1 and
358-1, respectively, and force those plates toward a more vertical
alignment. Here, plate 358-1 is forced against the left side of
spinous process 14-2, urging spinous process 14-2 to rotate and/or
translate toward a corrected vertical alignment directly inferior
to spinous process 14-1 (as depicted in FIG. 22E).
[0240] This configuration provides for a self-adjusting corrective
force that can take into account slow movement of the vertebral
bodies over the course of usage of system 350. For instance, as the
vertebral body of spinous process 14-2 moves toward a proper
alignment, the magnitude and direction of the corrective force
applied by plates 357-1 and 358-1 will likewise adjust to
compensate for this movement, yet continue to urge the vertebral
body toward the proper alignment.
[0241] The relative corrective force applied by each bias element
394 and 395 can be varied so as to apply relatively more force from
one side of the system if needed. Also, the force applied by the
bias elements on the superior side of the link can be relatively
greater or weaker than the force applied on the inferior side. For
instance, in this embodiment, bias elements 394-1 and 395 are
preferably stronger than bias elements 394-2 and 395-2,
respectively, to bias outer link 351 toward a more vertical
orientation, i.e., to force outer link 351-1 to rotate in a
clockwise direction about the inferior base of inner link 352-1.
The medical professional could choose to use more rigid springs
(i.e., configured to apply a relatively greater bias) directly
adjacent to vertebral bodies that have greater misalignment. The
medical professional may also choose to use springs that are
relatively weaker near the superior and inferior ends of the
construct to taper off the applied forces.
[0242] In the embodiment described with respect to FIGS. 22E-F,
insertion of system 350 over the spinous processes itself is
sufficient to maintain system 350 in place on the spinal column.
FIG. 22G is an exploded perspective view of another example
embodiment, where system 350 is directly attached to each of the
spinous processes in the region of the spine to be treated. It
should be noted that the system 350 can be coupled to any number of
spinous processes and it is not required to be connected to every
spinous process in the region to be treated.
[0243] Here, plates 357-1 and 358-1 of outer link 351 include a
superiorly located longitudinal slot 505-1 and 506-1, respectively.
The inferior side of each plate includes a rounded aperture 507-1
and 508-1, respectively. Likewise, plates 359 and 360 of the inner
links 352 each include superiorly located longitudinal slots 501
and 502 as well as inferiorly located rounded apertures 503 and
504, respectively. Preferably, a through-hole is created in each
spinous process 14 through which guide element 391 can be inserted,
though guide element 391 could be attached to the spinous process
in any manner as described with respect to FIGS. 4A-12D. Here,
guide element 391 also acts as an engagement device for coupling
system 350 to the spinal column Annular spacers 397 are preferably
positioned about guide element 391 on both sides of spinous process
14 and are used to provide spacing between the bone and the
corrective system as well as to provide cushioning and/or to more
evenly apply corrective force across the surface of the spinous
process 14.
[0244] Also shown here are bias members 394 and 395 for placement
on the guide element 391 after guide element 391 has been inserted
through the plates of the inner and outer links 351 and 352.
Attachable retaining elements 392 and 393 are coupled with the ends
of guide element 391 to retain bias element 394 and 395 on guide
element 391. In this embodiment, the ends of guide elements 391 are
threaded and retaining elements 392 and 393 are configured as nuts
that can be screwed thereon. One of skill in the art will readily
recognize that many different attachable configurations can be used
for retaining element 392 and 393.
[0245] A guide element with a circular cross section allows for
rotation of the plates about the guide element with relatively low
friction. The rounded apertures fix the respective plates with
respect to the guide element, while the slots allow for flexion and
extension of the spine. Additional longitudinal slots can be used
instead of the rounded apertures, if desired, so long as the plates
are prevented from excessive movement.
[0246] FIGS. 22H-J depict additional example embodiments of system
350. FIG. 22H is a posterior view of a patient's spinal column with
an example embodiment of system 350 having only one link 171
spanning the region between each vertebral body 11. These links 171
are coupled with transverse processes 15-1 of each vertebral body
as opposed to spinous process 14. As noted herein, there are
certain drawbacks to this approach; namely, the method of
implantation necessary to gain access to the transverse process is
relatively more invasive and risks excessive blood loss. However,
such a manner of attachment can be employed should it be
desired.
[0247] Both ends of each link 171 are coupled to a transverse
process 15. For instance, the upper end of the most superior link
171-1 shown here is coupled with a housing (or engagement device)
172 that attaches over transverse process 15-1. Link 171-1 is
preferably attached to housing 172 using guide element 174, which
is also routed through bias element 175 (similar to bias elements
394 and 395 described previously) and through a longitudinal slot
(not shown) in link 171-1. Housing 172 is, in turn, coupled with
transverse process 15-1 by a bone anchor 173. A similar
configuration is used to couple the remaining links to the adjacent
transverse processes with adjacent links connected in an
overlapping manner. The presence of bias elements 175 and
longitudinal slots allows deformation from the alignment shown here
to be corrected while at the same time allowing the patient to move
in the sagittal plane.
[0248] FIG. 22I depicts a similar embodiment to FIG. 22H coupled
with the lateral side of the main body portion of each vertebral
body 11 with guide element 174, which also serves as an engagement
device. Attachment in this manner allows system 350 to be placed
closer to the major axis of the patient's spinal column and
directly to the vertebral bodies to be corrected, as opposed to the
posteriorly positioned processes. Also shown here are longitudinal
slots 177 positioned to allow guide elements 174 to slide
therein.
[0249] FIG. 22J depicts another example embodiment of system 350
where multiple links 171 span the region between two adjacent
spinous processes 14. This or a similar configuration can be used
to couple with additional spinous processes of other vertebral
bodies as well. Here, the most superior link 171-1 is coupled
directly to spinous process 14-1 with an anchor element (or
engagement device) 176-1. Link 171-1 is also coupled to an
inferiorly located link 171-2 with a guide element 174-1 having a
bias element 175-1 placed between an enlarged end of guide element
174 and the adjacent link plate. Although not shown, guide element
174 is preferably placed through a longitudinal slot (similar to
slot 177 of FIG. 22I) in one of links 171-1 and 171-2. Similar
attachments are present for links 171-3, 171-4 and 171-5, which are
the most inferiorly located links. Link 171-5 is in turn coupled
with the spinous process 14-2 with anchor element 176-2.
[0250] FIG. 22K is a top-down view of another example embodiment of
system 350 where only one type of link 362 is used. Here, link 362
has a rigid uni-body construction with a multisided, stepped shape
that is complementary to the shape on the opposite side. This
configuration allows each link to interface with each adjacent link
to provide a closer fit and to allow each link to be coupled
together with a single guide element 363. Based on this disclosure,
one of ordinary skill in the art will readily recognize that many
similar shapes can be used instead of this multisided or stepped
shape. Although not shown, each guide pin 363 is preferably
contained within a longitudinal slot in one or both of each
adjacent links 352 to allow the same pivoting movement and
longitudinal translative movement as described with respect to
FIGS. 22A-C. Each link 362 can be a solid element or can include
multiple plates as described with respect to FIG. 22D.
[0251] The example embodiments of FIGS. 22A-H can each be used
instead of a rigid rod, as described with respect to the earlier
embodiments herein. For instance, one or more link-based systems
350 can be contained within tubular sleeves and used instead of the
rigid rods of FIGS. 2A-B and the rod bundles of FIGS. 2C-D. Also,
each link-based system 350 can be coupled directly to the adjacent
spinous processes as shown and described with respect to FIG.
22D.
[0252] FIGS. 23A-B depict an example embodiment of system 100
including one or more corrective sections 365. Each section 365
preferably includes a U-shaped or parabolic channel 366 with
opposing sidewalls 367-1 and 367-2. Section 365 is preferably
curved along its longitudinal axis or otherwise shaped to apply the
appropriate corrective force. FIG. 23A is a bottom-up view of
section 365, and a perspective view is shown in FIG. 23B. In this
example, section 365 is coupled over three adjacent spinal
processes 14. The middlemost spinous process 14-2 has a guide
element 368 routed through a man-made aperture therein. Guide
element 368 is also contained within two longitudinal slots 369-1
and 369-2 present on opposite sides of section 365. This
configuration allows section 365 to slide and pivot about element
368 as the patient's spinal column transitions through flexion and
extension. Multiple adjacent sections 365 can be used to treat
patients having deformities present over a larger span of the
spinal column. Section 365 can be configured to cover any number of
two or more spinous processes with the preferred configuration
being three as shown in FIG. 23B. If desired, additional slots 369
and guide elements 368 can be included for one or more other
spinous processes. In such an example, slots 369 can be offset
above and below each other to allow sufficient space between
them.
[0253] FIG. 24 is a side view of a patient's spinal column with
another example embodiment of a corrective treatment system 370.
Here, lumbar vertebrae L1 and L2 are shown having corrective system
370 attached thereto. System 370 includes two connectors (or
engagement devices) 371 and 372 securely coupled to the spinous
processes of vertebrae L1 and L2. Connectors 371 and 372 can each
be coupled with the spinous process in any desired manner,
including but not limited to the methods of attachment described in
the many embodiments herein. Connector 371 includes a base plate to
which a retaining guide element 375 is coupled. Similarly,
connector 371 also includes a base plate with a guide element 374
(e.g., a pin and the like) coupled thereto.
[0254] An elongate rigid strut (or plate) 373 is connected to each
of the opposing connectors 371 and 372. Strut 373 can be curved or
otherwise shaped to apply a corrective force on the adjacent
vertebral bodies. Strut 373 includes a longitudinal slot 376 in
which guide element 375 is retained by an enlarged head portion of
guide element 375. Strut 373 also includes an aperture (not shown)
that receives guide element 374 on connector 372. Again, guide
element 374 also preferably includes an enlarged head to retain
strut 373. Strut 373 can pivot around guide element 374 and guide
element 375. Strut 373 can also translate longitudinally with
respect to guide pin 375 but is held in position relative to guide
element 374 by the absence of a corresponding similar slot. This
configuration can be used on two or more adjacent vertebrae,
preferably with connectors 371 coupled to any additional vertebrae
and corresponding slots 376 present on strut 373 to allow sliding
translation with respect to each additional vertebral body. At
least one such connector 372 is preferably included to maintain
strut 373 in the proper position. This configuration allows the
application of corrective force in the coronal plane while at the
same time allowing the patient to enjoy significant freedom of
movement during flexion and extension.
[0255] It should be noted that various embodiments are described
herein with reference to one or more numerical values. These
numerical value(s) are intended as examples only and in no way
should be construed as limiting the subject matter recited in any
claim, absent express recitation of a numerical value in that
claim.
[0256] While the embodiments are susceptible to various
modifications and alternative forms, specific examples thereof have
been shown in the drawings and are herein described in detail. It
should be understood, however, that these embodiments are not to be
limited to the particular form disclosed, but to the contrary,
these embodiments are to cover all modifications, equivalents, and
alternatives falling within the spirit of the disclosure.
* * * * *