U.S. patent application number 15/374578 was filed with the patent office on 2017-03-30 for systems and methods for manipulating and/or installing a pedicle screw.
The applicant listed for this patent is Alphatec Spine, Inc.. Invention is credited to Clark Hutton, Kai-Uwe Lewandrowski, Ketchen Smith.
Application Number | 20170086884 15/374578 |
Document ID | / |
Family ID | 38654537 |
Filed Date | 2017-03-30 |
United States Patent
Application |
20170086884 |
Kind Code |
A1 |
Hutton; Clark ; et
al. |
March 30, 2017 |
SYSTEMS AND METHODS FOR MANIPULATING AND/OR INSTALLING A PEDICLE
SCREW
Abstract
A nested dilation tube assembly for enabling implantation of a
spinal screw assembly into a vertebrae is provided. The dilation
tube assembly includes a plurality of dilation tubes. Each dilation
tube includes an elongated cylindrical shaft with an outer diameter
slightly larger than a preceding dilation tube. After being
inserting into a body, the plurality of dilation tubes form a
nested, concentric assembly enabling an opening placed in the
spinal area and/or vertebrae to be enlarged up to the outer
diameter of a last dilation tube. The inner dilation tubes are
capable of being removed from outer dilation tubes such that the
inner diameter of an inner most remaining dilation tube forms a
space for receiving instruments and/or assemblies.
Inventors: |
Hutton; Clark; (Delmar,
CA) ; Smith; Ketchen; (Escondito, CA) ;
Lewandrowski; Kai-Uwe; (Tucson, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Alphatec Spine, Inc. |
Carlsbad |
CA |
US |
|
|
Family ID: |
38654537 |
Appl. No.: |
15/374578 |
Filed: |
December 9, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14453058 |
Aug 6, 2014 |
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15374578 |
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11820312 |
Jun 18, 2007 |
8834527 |
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14453058 |
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60814406 |
Jun 16, 2006 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/7034 20130101;
A61B 17/8897 20130101; A61B 17/7079 20130101; A61B 17/7032
20130101; A61B 2017/0256 20130101; A61B 17/7004 20130101; A61B
17/0218 20130101; A61B 17/7011 20130101; A61B 17/7037 20130101;
A61B 17/708 20130101; A61B 2090/037 20160201; A61B 2017/3433
20130101 |
International
Class: |
A61B 17/70 20060101
A61B017/70; A61B 17/02 20060101 A61B017/02 |
Claims
1. A nested dilation tube assembly for opening a surgical site, the
nested dilation tube assembly comprising: a plurality of dilation
tubes having at least an inner dilation tube, a medial dilation
tube and an outer dilation tube, each of the plurality of tubes
have an elongated cylindrical shaft with a bore, each of the
elongated cylindrical shaft having an outer diameter, wherein the
outer diameter of the outer dilation tube is larger than the outer
diameter of the medial dilation tube, and the outer diameter of the
medial dilation tube is larger than the outer diameter of the inner
dilation tube so as to allow the plurality of dilation tubes to
form a nested, concentric assembly enabling an opening to be
enlarged up to the outer diameter of the outer dilation tube.
2. The nested dilation tube assembly as set forth in claim 1,
wherein the inner dilation tube is configured to be removed from
the outer dilation tube so as to provide a space for receiving
instruments and/or assemblies for implantation into the surgical
site.
3. The nested dilation tube assembly of claim 1, further including
a wire, the wire configured to slide within the bore of the inner
dilation tube so as to form an initial opening, wherein each of the
plurality of dilation tubes may be sequentially inserted into the
surgical site so as to progressively enlarge the surgical site.
4. The nested dilation tube assembly of claim 1, wherein the inner
dilation tube is longer than the medial dilation tube, and the
medial dilation tube is longer than the outer dilation tube.
5. The nested dilation tube assembly of claim 1, wherein the inner
dilation tube includes a first lip disposed on a proximal end of
the inner dilation tube.
6. The nested dilation tube assembly of claim 5, wherein the first
lip is a flared protrusion.
7. The nested dilation tube assembly of claim 1, wherein the medial
dilation tube includes a second lip disposed on a proximal end of
the medial dilation tube.
8. The nested dilation tube assembly of claim 7, wherein the second
lip is a flared protrusion.
9. The nested dilation tube assembly of claim 1, wherein each of
the plurality of dilation tubes a pointed head disposed on a distal
end of each of the elongated cylindrical shaft the a respective one
of the plurality of dilation tubes.
10. The nested dilation tube assembly as set forth in claim 9,
wherein the pointed head of the inner dilation tube is narrower
than the pointed head of the medial dilation tube, and the pointed
head of the medial dilation tube is narrower than the pointed head
of the outer dilation tube.
11. A method of making a surgical opening in a surgical site, the
method comprising the steps of: providing a plurality of dilation
tubes having at least an inner dilation tube, a medial dilation
tube and an outer dilation tube, each of the plurality of tubes
have an elongated cylindrical shaft with a bore, each of the
elongated cylindrical shaft having an outer diameter, wherein the
outer diameter of the outer dilation tube is larger than the outer
diameter of the medial dilation tube, and the outer diameter of the
medial dilation tube is larger than the outer diameter of the inner
dilation tube; providing a wire, the wire disposed within the inner
dilation tube; inserting the wire into the surgical site; inserting
the inner dilation tube into the surgical site; sliding the medial
dilation tube over the inner dilation tube so as to enlarge the
surgical site; sliding the outer dilation tube over the medial
dilation tube so as to enlarge the surgical site, wherein the inner
dilation tube, the medial dilation tube and the outer dilation tube
form a nested, concentric assembly.
12. The method as set forth in claim 11, further including the
following steps in sequence: removing the wire from the surgical
site; removing the inner dilation tube from the surgical site; and
removing the medial dilation tube from the surgical site.
13. The method as set forth in claim 12, further including the step
of inserting a screw into the surgical site within the bore of the
elongated cylindrical shaft of the outer dilation tube.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional of U.S. application
Ser. No. 14/453,058 filed on Aug. 6, 2014 which is a continuation
of U.S. application Ser. No. 11/820,312 filed on Jun. 18, 2007, now
issued as U.S. Pat. No. 8,834,527, which claims the benefit of U.S.
Provisional Application Ser. No. 60/814,406, filed on Jun. 16,
2006, the entire contents of which are herein incorporated herein
by reference.
FIELD OF THE INVENTION
[0002] The present invention is generally directed to installing
and adjusting a spinal screw assembly and, more specifically, to
systems and methods for providing an adjustable securement of a
fixation rod to or across one or more vertebrae.
BACKGROUND OF THE INVENTION
[0003] The spinal column is a highly complex system of bones and
connective tissues that provides support for the body and protects
the delicate spinal column and nerves. The spinal column includes a
series of vertebrae stacked one atop the other, whereby each
vertebral body includes a relatively strong bone portion forming
the outside surface of the body and a relatively weak bone portion
from the center of the body. Situated between each vertebral body
is an intervertebral disc formed from a non-bony, fibro-cartilage
material that provides for cushioning and dampening of compressive
forces applied to the spinal column. The vertebral canal containing
the delicate spinal cords and nerves is located just posterior to
the vertebral bodies.
[0004] Various types of spinal column disorders are known and
include scoliosis (abnormal lateral curvature of the spine),
kyphosis (abnormal forward curvature of the spine, usually in the
thoracic spine), excess lordosis (abnormal backward curvature of
the spine, usually in the lumbar spine), spondylolisthesis (forward
displacement of the one vertebra over another, usually in a lumbar
or cervical spine) and other disorders caused by abnormalities,
disease or trauma, such as ruptured or slipped discs, degenerative
disc disease, fractured vertebra, and the like. Patients suffering
from such conditions usually experience extreme and debilitating
pain as well as diminished nerve function.
[0005] Certain spinal conditions as mentioned above, including a
fracture of a vertebrae and a herniated disc, indicate treatment by
spinal immobilization. Several methods of spinal joint
immobilization are known, including surgical fusion and the
attachment of pins and bone plates to the affected vertebras.
[0006] In an attempt to effectively treat the above-described
conditions and, in most cases to relieve pain suffered by the
patient, there have been numerous spinal fixation techniques
developed to remedy such issues. Nonetheless, as will be set forth
in more detail below, there are some disadvantages associated with
current fixation techniques and devices. U.S. Pat. No. 6,030,388
(granted Feb. 29, 2000 to Yoshimi, et al.) discusses prosthetic
devices used in bone fixation systems, such as those used to treat
degenerative and trauma related spinal deformities. This patent
discusses a bone fixation element, a linking member and a coupling
member having a first channel for receiving a portion of the bone
fixation element and a second channel for receiving a portion of
the linking member. The channels are oriented within the coupling
member such that the central longitudinal axes of the first and
second channels are offset with respect to one another.
Furthermore, the first and second channels are configured within
the coupling member so as to provide for communication of a
securing force between the bone fixation element and the linking
member such that the bone fixation element is rigidly secured with
respect to the linking member.
[0007] U.S. Publication No. 2005/0131408 (granted on Jun. 16, 2005
to Sicvol, Christopher W., et al.) discusses delivery and
implantation of bone anchors into bone, in particular, one or more
vertebral bodies of the spine. This patent discusses a bone anchor
having a distal bone engaging portion and a receiving member having
a recess for receiving a spinal fixation element. The proximal end
of the receiving member may have an arcuate groove formed on an
exterior surface thereof to facilitate connection of an instrument
to the receiving member.
[0008] U.S. Pat. No. 6,802,844 (granted on Oct. 12, 2004 to Ferree)
discusses bodies which connect to vertebra to be aligned, and
elongated elements that connect to the bodies, which are adjustable
relative to the bodies in multiple dimensions. The patent further
discusses locking mechanisms that allow the alignment to proceed in
an orderly fashion until a desired degree of correction is
achieved. Each elongated element has a shaped end terminating in
the first portion of the lockable coupling mechanism. The vertebral
connector bodies each include a feature for attaching the body to
respective vertebrae, and the second portion of the lockable
coupling mechanism.
[0009] U.S. Pat. No. 5,772,661 (granted on Jun. 30, 1998 to
Michelson) discusses a method and instrumentation for performing
spinal surgery, including discectomy, interbody fusion and rigid
internal fixation of the spine, from the lateral aspect of the
spine. This patent discusses a surgical procedure consisting of the
removal of spinal material across the disc, fusion, and rigid
internal stabilization via the implant may all be performed via the
closed space within the extended outer sleeve.
[0010] Thus, it is desirable to provide improved systems for
internal fixation of adjacent vertebral bodes of the spine.
Accordingly, some embodiments of the present invention provide an
extended range of motion (as compared to the prior art) for
allowing a surgeon additional freedom in locating the screws and
easing the assembly process by reducing the requirements for rod
contouring. Such embodiments of the present invention minimizes,
and in some aspects eliminates, the failures of the prior art, and
other problems, by utilizing the structural features described
herein. Thus, the result is a significantly improved system and
method for manipulating and installing a pedicle screw.
[0011] The features and advantages of the invention will be set
forth in the description which follows, and in part will be
apparent from the description, or may be learned by the practice of
the invention without undue experimentation. The features and
advantages of the invention may be realized and obtained by means
of the instruments and combinations particularly pointed out in the
drawings, subsequent detailed description and appended claims.
SUMMARY OF THE INVENTION
[0012] The foregoing and other features, aspects, and advantages of
the present invention will be more apparent from the following
detailed description, which illustrates exemplary embodiments of
the present invention. Some of the embodiments of the present
invention relate to a spinal screw assembly for providing an
adjustable securement of a stabilization rod between at least two
vertebrae. The assembly is preferably used with at least one other
such assembly to secure the fixation rod.
[0013] In an embodiment of the present invention, a spinal screw
assembly adapted to be secured to a vertebrae is provided. The
spinal screw assembly includes a pedicle screw having a head, a
threaded shaft portion, and an engagement surface in the head
portion for driving the screw into the vertebrae. The spinal screw
assembly also includes a body member for receiving the head portion
of the screw. The body member entails a base from which the
threaded shaft portion projects, a tower portion, and a pair of
opposed slots therein adapted to receive a portion of a fixation
rod therebetween. Provided between the base and the tower portion
is a break-away section which allows the tower portion to be
removed from the base.
[0014] In an embodiment, the spinal screw assembly further details
a securable setscrew for threading onto corresponding threads
provided adjacent the pair of opposed slots. The setscrew is
adapted to bear against a portion of the fixation rod disposed
between the pair of opposed slots to secure the fixation rod within
the assembly.
[0015] In an embodiment, the spinal screw assembly details at least
a portion of the break-away section including threads corresponding
to threads of the setscrew and threads of the base. The threads of
the break-away section allows the setscrew to traverse the
break-away section into the base.
[0016] In an embodiment of the present invention, a fixation rod is
provided. The fixation rod is adapted for securement between at
least two spinal screw assemblies. The fixation rod includes a rod
body having a predetermined length and one or more engagement
portions provided on at least one end of the rod.
[0017] In an embodiment, the fixation rod further details
engagement portions selected from a group consisting of a
depression, an opening, a nib, a protrusion, a clip, a snap ring, a
washer and a flared end. The flare portion includes at least a
portion of the perimeter of the end. Also, the nib, protrusion or
flared end may be integral with the rod. The clip, snap ring and/or
washer may be received by a groove machined into fixation rod.
[0018] In an embodiment of the present invention, a compressor tool
for compressing together at least two vertebrae is provided. The
compressor tool includes a shaft having a first end for engaging a
screw assembly, and a lever having a first end and a second end.
The first end of the lever is movably attached to the first end of
the shaft and includes an engagement portion for engaging an end of
a fixation rod positioned within the screw assembly when the lever
is in a first position prior to compression. The compressor also
includes a handle attached to the shaft at a second end opposite
the first end.
[0019] In an embodiment, the compressor tool further details the
lever including a first portion having a first length and being
provided adjacent the first end. The first portion is provided at
an angle relative to the remainder of the length of the lever. The
lever is movably attached to the shaft at a point where the angle
of the first portion begins relative to the remainder of the length
of the lever.
[0020] In an embodiment of the present invention, a nested dilation
tube assembly for enabling implantation of a spinal screw assembly
into a vertebrae is provided. The dilation assembly includes a
plurality of dilation tubes of increasing diameter. Each dilation
tube includes an elongated cylindrical shaft with an outer diameter
slightly larger than a preceding dilation tube. After being
inserting into a body, the plurality of dilation tubes form a
nested, concentric assembly enabling an opening placed in the
spinal area and/or vertebrae to be enlarged up to the outer
diameter of a last dilation tube. The inner dilation tubes are
capable of being removed from outer dilation tubes such that the
inner diameter of an inner most remaining dilation tube forms a
space for receiving instruments and/or assemblies for implantation
into a vertebrae.
[0021] In an embodiment, the nested dilation tube assembly further
includes a wire for forming an initial opening into the spine
and/or vertebrae. The plurality of nested dilation tubes fit over
the wire and enable an opening in the spine formed by the wire to
be enlarged up to the outer diameter of a last dilation tube.
[0022] In an embodiment of the present invention, a spinal screw
assembly system is provided. The spinal screw assembly system
includes a nested dilation tube assembly for enabling implantation
of a spinal screw assembly into a vertebrae. The dilation assembly
includes a plurality of dilation tubes of increasing diameter, each
comprising an elongated cylindrical shaft. Each dilation tube
includes an outer diameter slightly larger than a preceding
dilation tube. After insertion into a body, the plurality of
dilation tubes form a nested, concentric assembly enabling an
opening placed in the spinal area and/or vertebrae to be enlarged
up to the outer diameter of a last dilation tube. Inner dilation
tubes are capable of being removed from outer dilation tubes such
that the inner diameter of an inner most remaining dilation tube
forms a space for receiving a spinal screw assembly for
implantation into a vertebrae. The system also includes spinal
screw assembly is adapted to be secured to a vertebrae, which
includes a pedicle screw having a head, a threaded shaft portion,
and an engagement surface in the head portion for driving the screw
into the vertebrae. The spinal screw assembly further includes a
body member for receiving the head portion of the screw. The body
member includes a base from which the threaded shaft portion
projects, a tower portion, a pair of opposed slots therein adapted
to receive a portion of a fixation rod therebetween. A break-away
section provided between the base and the tower portion allowing
the tower portion to be removed from the base subsequent to
installation. A compressor tool for compressing together at least
two vertebrae is also provided within the system. The compressor
tool includes a shaft having a first end for engaging the screw
assembly, and a lever having a first end and a second end. The
first end being movably attached to the first end of the shaft and
including an engagement portion for engaging an end of a fixation
rod positioned within the screw assembly when the lever is in a
first position prior to compression.
[0023] Other objectives and advantages of the present invention
will become obvious to the reader and it is intended that these
objectives and advantages are within the scope of the present
invention.
[0024] To accomplish the above and related objectives, this
invention may be embodied in the form illustrated in the
accompanying drawings, attention being called to the fact, however,
that the drawings are illustrative only, and that changes may be
made in the specific construction illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] For a better understanding of the present invention,
reference is made to the following description, taken in
conjunction with the accompanying drawings, in which like reference
characters refer to like parts throughout, and in which:
[0026] FIG. 1A is a pedicle screw for the use in a spinal screw
assembly according to some embodiments of the present
invention.
[0027] FIG. 1B illustrates a perspective view of a spinal screw
assembly and its components according to an embodiment of the
present invention.
[0028] FIG. 1C illustrates a fragmented perspective view of the
spinal screw assembly and its components according to an embodiment
of the present invention.
[0029] FIGS. 1D-F are fragmented perspective views of the spinal
screw assembly according to an embodiment of the present
invention.
[0030] FIG. 2 illustrates a perspective view of a plurality of
polyaxial screw assemblies according to an embodiment of the
present invention, with a rod traversing therethrough.
[0031] FIG. 3 is a perspective view of a plurality of polyaxial
screw assemblies according to an embodiment of the present
invention, with a rod having traversed therethrough.
[0032] FIGS. 4A-C illustrate extruded features at ends of the
fixation rod in accordance with some embodiments of the present
invention.
[0033] FIGS. 5A-E illustrate the features and assembly according to
a dilation instrument according to some embodiments of the present
invention.
[0034] FIGS. 6A-C illustrate the features and assembly according to
a compression instrument according to some embodiments of the
present invention
DETAILED DESCRIPTION
[0035] It is noted that in this disclosure and particularly in the
claims and/or paragraphs, terms such as "comprises," "comprised,"
"comprising," and the like can have the meaning attributed to it in
U.S. patent law; that is, they can mean "includes," "included,"
"including," and the like, and allow for elements not explicitly
recited. These and other embodiments are disclosed or are apparent
from and encompassed by, the following description.
[0036] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of other embodiments and of being practiced
and carried out in various ways where particular configurations,
process steps, and materials disclosed herein as such
configurations, process steps, and materials may vary somewhat. In
addition, it is to be understood that the phraseology and
terminology employed herein are for the purpose of the description
and should not be regarded as limiting. Furthermore, as will be
apparent to those skilled in the art, the present invention may be
embodied in other specific forms without departing from the
essential characteristics thereof.
[0037] For purposes of the description of the drawings and the
embodiments of the present invention, as mentioned for each
drawing, each figure may not drawn to scale. Some areas drawn may
be bigger and/or simpler in order to clearly portray the
improvement to what has already been established. It will
nevertheless be understood that no limitation of the scope of the
invention is thereby intended. Any alterations and further
modifications of the inventive features illustrated herein, and any
additional applications of the principles of the invention as
illustrated herein, which would normally occur to one skilled in
the relevant art and having possession of this disclosure, are to
be considered within the scope of the invention claimed. It is also
to be understood that the terminology employed herein is used for
the purpose of describing particular embodiments only and is not
intended to be limiting since the scope of the present invention
will be limited only by the appended claims and equivalents
thereof.
[0038] Referring now in detail to the drawings, the spinal screw
assembly 100 of the present invention comprises a pedicle screw
102, a body member 104, a bushing 114 and a setscrew 302 for
providing an adjustable securement of a stabilization rod 202
between at least two vertebrae (not shown). The spinal screw
assembly 100 is used with at least one other such assembly to
secure the fixation rod 202. The present invention allows a pedicle
screw 102 to be implanted in a minimally invasive or percutaneous
method.
[0039] FIGS. 1A-F illustrate perspective views of a spinal screw
assembly 100 and its components according to an embodiment of the
present invention. FIG. 1A details the pedicle screw 102 which is
employed in the assembly 100. The pedicle screw 102 is a canulated
screw (polyaxial or otherwise) design for the purpose of fusing the
thoracolumbar spine. The screw 102 is typically intended to
canulate the pedicle, be supplemented by a rod 202 construct, and
held in place with a setscrew 302, also referred to as top loaded
setscrew, as described below. Pedicle screw 102 is a polyaxial
pedicle screw, which typically includes a spherical head portion
105, a threaded shaft portion 103 and an engagement surface 107 in
the head portion 105 for use in driving the screw 102 into
vertebrae (not shown).
[0040] FIG. 1B details the interaction between the screw 102 and
body member 104 of the spine screw assembly 100. The body member
104 includes a high top or tower portion 106, base body 108, break
zone 110, threads 116, bushing 114, a pair of opposed parallel
slots 130 and additional features 119 for attachment of
supplemental devices, as described below. The tower 106 may enable
a fully seated (i.e., implanted) screw 102 to be manipulated or
aligned, in multiple directions. In particular, the tower 106
allows such functionality from outside the wound (not shown). The
tower 106 is constructed preferably of a breakable web of material,
which allows the tower 106 to be easily removed (e.g., the web of
materials are broken) from the body member 104 at the break zone
110. The break zone 110 is included at the transition of the tower
106 and the base body 108. The top tower 106 acts as a break-away
section in that, once the screw 102 has been fully assembled, in
which the spine screw assembly is locked via the setscrew 302, the
top portion 106 is removed or broken off. In a preferred
embodiment, after the tower 106 has been removed, or broken off,
the assembly 100 sit flush with the wound, where no protruding
components remain outside of the wound. Alternatively, the
components could remain below the wound as well, which is
understood by one of ordinary skill in the art.
[0041] The tower 106 may be threaded 116, in which the thread 116
is clocked in time to the threaded shaft 103 of the screw 102.
Using a continuous thread allows for the setscrew 302 to reduce a
rod 202 from tower 106 to the base body 108 for stabilization of a
fixation rod 202. The tower 106 further includes an open top 118 to
aid in visualization and allow uninterrupted access down the body
member 104.
[0042] FIG. 1C illustrates a fragmented perspective view of the
spinal screw assembly and its components according to an embodiment
of the present invention. This fragmented view shows that the
threaded transition 116 exists between the transition of the tower
106 and the base 108 through the break zone 110. The threaded
transition 116 that exists between the tower 106, base 108 and
break zone 110 correspond to threads 304 of the setscrew 302. The
threads 116 of the break-away section 110 allow the setscrew 302 to
traverse the break-away section 110 into the base 106.
[0043] Additionally, as discussed below in relation to FIGS. 5A-E,
the tower 106 includes additional features 119 (e.g., threads) at
the top of the tower 106 to attach screwdrivers 504, alignment
jigs, and other supplemental devices to engage the spine screw
assembly into vertebrae.
[0044] FIGS. 1D-F illustrate the components of the base body 108 of
the body member 104 where the stabilization of the fixation rod 202
and screw 102 occurs. The outer or upper interior surface of side
walls 122 of the base body 108 both have radially projecting
serrations formed therein defining the plurality of axially aligned
threads 116. The base body 108 shows the pair of opposed parallel
slots 130 axially disposed in the side wall 122 thereof, which
terminate at their lower ends in curvilinear surfaces 126. The
parallel slots 130 are sized to receive the fixation rod 202
therein, as shown below, with the walls 124 defining the slots 130.
The slots 130 extending upwardly beyond the break zone 110 up to
the distal end of the tower portion 106 may be inclined slightly to
provide a slight holding force on the rod 202 prior to securing the
rod 202 with the setscrew 302. The pair of opposed parallel slots
130 are adapted to receive a portion of the fixation rod 202 as a
setscrew 302 bears against the fixation rod 202 to releasably
secure the rod 202 within the assembly 100, as described below.
Alternatively, a surgeon may exert a slight downward force on the
rod 202, snapping the rod 202 into the transverse channel defined
by the aligned slots 130.
[0045] The head portion 106 of the screw 102 is typically
positioned in a body member 104 adjacent a curvilinear surface 126
disposed about an aperture 109 in the end of the base body 106,
such that the threaded shaft portion 103 of the screw 102 extends
therethrough and the curvilinear inner surface 126 abuts and mates
with the head portion 105 of the screw 102 so as to define a ball
joint therewith. The rounded head surface of the head portion 105
rests upon and mates with a rounded interior surface formed in the
inner or lower end of the base body so as to form a modified ball
joint that provides the desired variable angular movement of the
body member with respect to an embedded pedicle screw 102. The
threaded shaft portion 103 of screw 102 extends therefrom through
the opening 112 in the lower end of base body 108, as pictured in
FIG. 1F.
[0046] A bushing 114 is preferably employed within the base body
108 adjacent to the side walls 122 to better distribute the
longitudinal forces exerted on the pedicle screw 102; thereby the
bushing 114 provides a seat for the fixation rod 202. The bushing
114 further provides flexibility therein and may provide tapered
end surfaces adapted to abut opposed sides of the head portion 105.
The bushing 114 is positioned within the base body 108 of the body
member 104 and outwardly adjacent to the head portion 105 of said
screw 102. The bushing 114 further abuts the head portion 105 of
the screw 102 upon the setscrew 302 pressing against a portion of
the fixation rod 202 whereby the force exerted on the head portion
105 is distributed about the head portion 105.
[0047] To provide a basic stability to the system during initial
assembly, the bushing 114 can be configured to provide a press
fitment about the head portion 105 so that the pedicle screw 102,
body member 104 and bushing 114 will not move freely prior to the
insertion and securement of the fixation rod 202.
[0048] In another embodiment of the invention, the bushing 114 may
not be employed. The opposed axial slots 130 in the side wall 122
of the body member 104 of the assembly 100 define a seat for the
fixation rod 202. When the setscrew 302 is pressed into the body
member 104 with the fixation rod 202 extending there across, the
planar bottom surface abuts the fixation rod 202 and, in this
instance, presses the rod 202 against the upper end of the head
portion 105 of the pedicle screw. For such applications, the body
member 104 and pedicle screw 102 would be sized such that the upper
part of the head portion 105 of the screw 102 would project above
the bottom of the seat defined by the axially opposed slots 130 so
as to enable the rod 202 to press against the screw 102 and create
a rigid, yet adjustable, securement between the body member 104 and
the pedicle screw 202.
[0049] FIG. 2 illustrates a perspective view of a plurality of
polyaxial screw assemblies 100 according to an embodiment of the
present invention, with a rod 202 traversing therethrough. The
fixation rod 202 enters the body member 104 through each pair of
slots 130. The fixation rod 202 traverses down the body member 104
until it becomes fully seated within the parallel slots 130 of each
body member 104, as pictured below in relation to FIG. 3. The
fixation rod 202 may traverse each body member 104 though force
applied by a surgeon, through force applied by a setscrew 302
pushing the rod 202 down the body member or other means, which
would be recognized by one with skill in the art.
[0050] FIG. 3 is a perspective view of a plurality of polyaxial
screw assemblies 100 according to an embodiment of the present
invention, with a rod 202 having traversed therethrough. After
affixation of the rod 202 within the screw assemblies 100,
setscrews or setscrews 302 are utilized to lock the fully seated
rod 202 in place within the body member 104. The setscrew 302
includes threads 304 to engage the threaded portion 116 of the body
member 104. Accordingly, the threaded portion 116 of the body
member may be just a portion of the body member 104 or the entire
body member 104. The interlocked threads 304 of the setscrew 302
may allow the surgeon to tighten the clamping force on the fixation
rod 202 by simply pressing downwardly on the setscrew 302. The
threads 304 will hold the component parts in place. To adjust or
remove the rod 202, the setscrew 302 is simply rotated 90 degrees
about its longitudinal axis, whereupon the threads 304 of the cap
302 are aligned with the open slots 130 in the body member 104,
allowing the cap 302 to be simply pulled upwardly away from the
fixation rod 202. An engagement slot is provided in the top portion
of cap 302 to facilitate the rotation of the setscrew with a
suitably sized mating tool (not shown), which is well known in the
art.
[0051] FIGS. 4A-C illustrate extruded features at ends of the
fixation rod in accordance with embodiments of the present
invention. The fixation rod 202 may embody extruded features at the
ends of the rod 202. These features are configured to receive a
corresponding engagement portion of a compression tool 600 for
moving the fixation rod 202 relative to a spinal screw assembly 100
when the spinal screw assembly 100 is affixed to the vertebrae, as
discussed below in relation to FIGS. 6A-6C. As illustrated in FIG.
4A, the fixation rod 202 includes pegs, short spikes, nibs,
washers, or flared portions 402 protruding on the distal ends. The
flared portions 402 may include at least a portion of the perimeter
of the end of the fixation rod 202. In FIG. 4B, the fixation rod
202 includes snap ring clips 404 sitting in grooves, depressions or
openings (not shown) machined into the distal ends at a proximal
portion of the rod 202. FIG. 4C depicts the features of FIG. 1, the
pegs or short spikes 402 being machined into the fixation rod 202
as one piece. The above identified machined and extruded features
appended to the fixation rod 202 provide the benefits for use by a
surgeon. The rod 202 is fully contained within the body member 104
by the setscrew 302. The rod 202 also need not be tilted or the
body member 104, including the towers 106, stretched to allow the
rod 202 to be placed into a fully seated position. Furthermore,
these above identified features of 402 and 404 allow other
instruments to interact with the spine screw assembly 100, as
discussed below in relation to FIGS. 6A-6B, as well as other
embodiments which would be recognized by one skilled in the
art.
[0052] FIGS. 5A-E illustrate the features and assembly according to
a nested dilation tube assembly 500. FIG. 5A illustrates the
components utilized in the nested dilation tube assembly 500 in
accordance with the spine screw assembly 100. As pictured the screw
driver 504 (or any other type of mating tool) engages the body
member 104 atop the tower portion 106 via the additional features
119 (e.g., threads). The screw 102 and body member 104 enter a
dilator 502 (or tube) and thereby engage the vertebrae in
accordance with the embodiments of the present invention. As shown
in FIG. 5B, the dilation assembly 500 allows the surgeon to use a
small wire 501 and progressively dilate the vertebrae (not shown)
with a plurality of dilation tubs 502a-502d, each of the dilation
tubs having an increasingly greater diameter than the other from
the inner to the outer dilation tube. As shown in FIG. 5C, once the
smaller diameter dilator 502a (referenced also as the inner
dilation tube) has been implanted, larger diameter dilators 502b
(also referenced as the medial dilation tube) and 502c (also
referenced as the outer dilation tube) are implanted, respectively.
Upon increasing the diameter of the dilators 502a-502c by
implanting a dilator 502 with a greater diameter, previously
implanted dilators 502 with smaller diameters may be removed,
thereby increasing the opening in the vertebrae; hence, once the
largest tube 502c is utilized, the inner dilation tubes 502a and
502b can be removed. The dilation tubes 502 after being inserted
into a body form a nested, concentric assembly 500 enabling an
opening placed in the spinal area and/or vertebrae to be enlarged
up to the outer diameter of a last dilation tube 502c. It can be
recognized that one skilled in the art, that the smaller diameter
tubes 502 may be removed after each increase in diameter, or all
together at the end, after the largest diameter tube is employed.
Interior dilation tubes 502a and 502b entail a lip area as flared
protrusions 503a and 503b from the distal end of each tube. The
protrusions 503a and 503b allow for removal of each tube
accordingly. The protrusions 503a and 503b also prevent the tubes
502a and 502b from entering the assembly 500 beyond a predetermined
point. It would also be recognized by one of ordinary skill in the
art that a variety of number of dilation tubes 502 could be
utilized with assembly 500. FIG. 5D depicts the components of the
tube 502, body member and screw 102 as discussed above. As
illustrated in FIG. 5E, upon employment of the largest diameter
tube 502, the screw assembly 100 is implanted through the tube 502
via the use of the screw driver 504.
[0053] FIGS. 6A-C illustrate the features and assembly according to
a compression embodiment of the present invention. FIG. 6A
illustrates the compressor 600 including a handle 602, body shaft
604 and lever 606. The lever 606 includes a first end being movably
attached to the first end of the shaft 604 and including an
engagement portion (not shown) for engaging an end of a fixation
rod 202 positioned within the screw assembly when the lever is in a
first position prior to compression, and a second end utilized for
compression 600. Lever 606 further includes a portion having a
first length and being provided adjacent the first end. The first
portion is provided at an angle relative to the remainder of the
length of the lever 606. The lever 606 is movably attached to the
shaft 604 at a point where the angle of the first portion begins
relative to the remainder of the length of the lever 606. The shaft
604 connects the handle 602 and the lever 606 and embodies a
cylindrical shape adapted to slide over and down the spinal screw
assembly 100. The shaft 604 may entail a substantially tubular
shape that allows the shaft 604 to receive at least a portion of a
screw assembly 100 therein.
[0054] FIG. 6B illustrates the compressor 600 including the handle
602 located in conjunction with the distal end of the body member
104 atop the tower portion 106 and the lever 606 positioned in
conjunction with the fixation rod 202 which is fully seated in the
screw assembly 100. The compressor 600 is positioned adjacent to
the body member 104 and above the fixation rod 202, therein the
compressor 600 grabs hold of a protrusion of the fixation rod 202,
as discussed above in relation to FIGS. 4A-4C and elements 402 and
404. As illustrated in FIG. 6C, a load is applied to the fixation
rod 202 by manipulating the level 606 of the compressor 600 and
thereby applying a load to the fixation rod 202. To provide balance
or leverage upon applying the load to the fixation rod 202, the
surgeon can grip onto the handle 602. The fixation rod 202 is
displaced within the assembly 100 a distance up to a 5 mm range
upon increasing the applied load by a lever depression 608, whereby
the distance between a screw assemblies is decreased. Once the
desired compression is achieved, the setscrew 302 is finally
tightened upon the fixation rod 202 whereby the displacement and
compression are preserved.
[0055] As described in FIGS. 5A-E and 6A-C, after dilation and
compression occurs, it would be understood by one of ordinary skill
in the art that the tower portion would be broken off, as described
above, thereby creating a fully seated and implanted assembly.
[0056] While illustrative embodiments of the invention have been
described above, it is, of course, understood that various
modifications will be apparent to those of ordinary skill in the
art. Such modifications are within the spirit and scope of the
invention, which is limited and defined only by the appended
claims.
[0057] Although illustrative embodiments of the invention have been
described in detail herein with reference to the accompanying
drawings, it is to be understood that the invention is not limited
to those precise embodiments, and that various changes and
modifications can be effected therein by one skilled in the art
without departing from the scope and spirit of the invention as
defined by the appended claims.
* * * * *