U.S. patent application number 12/244781 was filed with the patent office on 2010-04-08 for fastener assembly that fastens to polyaxial pedicle screw.
Invention is credited to Assaf Klein, Eyal Zilberberg.
Application Number | 20100087864 12/244781 |
Document ID | / |
Family ID | 42076354 |
Filed Date | 2010-04-08 |
United States Patent
Application |
20100087864 |
Kind Code |
A1 |
Klein; Assaf ; et
al. |
April 8, 2010 |
FASTENER ASSEMBLY THAT FASTENS TO POLYAXIAL PEDICLE SCREW
Abstract
A fastener assembly including an existing polyaxial pedicle
screw that has been previously installed in a spinal structure, the
polyaxial pedicle screw including a polyaxial head to which a
prosthetic member is secured, a fastening portion fastened to the
polyaxial head over the prosthetic member, and a connector element
that extends from the fastening portion, the connector element
being connected to another spinal structure.
Inventors: |
Klein; Assaf; (Kibbutz
Hama'apil, IL) ; Zilberberg; Eyal; (Kfar Yona,
IL) |
Correspondence
Address: |
DEKEL PATENT LTD., DAVID KLEIN
BEIT HAROF'IM, 18 MENUHA VENAHALA STREET, ROOM 27
REHOVOT
76209
IL
|
Family ID: |
42076354 |
Appl. No.: |
12/244781 |
Filed: |
October 3, 2008 |
Current U.S.
Class: |
606/264 ;
606/246; 606/278; 606/301 |
Current CPC
Class: |
A61B 17/7091 20130101;
A61B 17/7049 20130101; A61B 17/7037 20130101; A61B 17/7043
20130101; A61B 17/7007 20130101; A61B 17/7055 20130101 |
Class at
Publication: |
606/264 ;
606/301; 606/246; 606/278 |
International
Class: |
A61B 17/70 20060101
A61B017/70; A61B 17/04 20060101 A61B017/04 |
Claims
1. A fastener assembly comprising: an existing polyaxial pedicle
screw that has been previously installed in a spinal structure,
said polyaxial pedicle screw comprising a polyaxial head to which a
prosthetic member is secured; a fastening portion fastened to said
polyaxial head over said prosthetic member; and a connector element
that extends from said fastening portion, said connector element
being connected to another spinal structure.
2. The fastener assembly according to claim 1, wherein said
fastening portion comprises a wedge ring and said connector element
comprises a conical ring into which said wedge ring fits, said
connector element comprising a connecting member that extends from
said conical ring, wherein said wedge ring is sized to fit over
said polyaxial head and said conical ring wedges said wedge ring
onto said polyaxial head.
3. The fastener assembly according to claim 2, wherein said wedge
ring has a conical periphery with a top surface that has a larger
outer diameter than a bottom surface thereof, and said conical ring
has a top surface with a larger inner diameter than a bottom
surface thereof, said larger outer diameter not being greater than
said larger inner diameter.
4. The fastener assembly according to claim 3, wherein a plurality
of grooves are formed in said conical periphery of said wedge
ring.
5. The fastener assembly according to claim 4, wherein at least one
of said grooves is open at the top surface and closed at the bottom
surface and at least another groove is closed at the top surface
and open at the bottom surface.
6. The fastener assembly according to claim 1, wherein said
fastening portion comprises a closed ring and said connector
element comprises a connecting member that extends from said closed
ring, and wherein said existing polyaxial pedicle screw comprises a
first mechanical fastener fastened to the polyaxial head, wherein
said closed ring is placed over said first mechanical fastener such
that said first mechanical fastener protrudes through said closed
ring, and further comprising a second mechanical fastener that
fastens to said first mechanical fastener and is tightened against
said closed ring.
7. The fastener assembly according to claim 6, wherein said closed
ring is not flush with said connecting member.
8. The fastener assembly according to claim 1, wherein said
fastening portion comprises an open ring that fits over said
polyaxial head and a mechanical fastener that fastens end portions
of said open ring towards each other so as to clamp said open ring
onto said polyaxial head, and said connector element comprises a
connecting member that extends from said open ring.
9. The fastener assembly according to claim 8, wherein said end
portions of said open ring are angled at an acute angle with
respect to a top surface of said open ring.
10. A method comprising: fastening a fastening assembly to a
polyaxial head of an existing polyaxial pedicle screw that has been
previously installed in a spinal structure, a prosthetic member
being secured to said polyaxial head, wherein said fastening
assembly comprises a fastening portion fastened to said polyaxial
head over said prosthetic member and a connector element that
extends from said fastening portion; and connecting said connector
element to another spinal structure.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to polyaxial fasteners,
such as a polyaxial pedicle screw assembly, and particularly to a
fastener assembly that fastens to polyaxial pedicle screws that
have already been installed in spinal structure.
BACKGROUND OF THE INVENTION
[0002] Polyaxial pedicle screw assemblies are well known in the art
and may be used for connecting vertebrae or other spinal structure
to rods in spinal surgery. For example, polyaxial pedicle screw
assemblies are known that incorporate a ball joint at the
connection to the rod to allow the surgeon some flexibility in
placing the screws. Tightening a nut on the screw compresses the
ball joint components to lock the angular position of the ball
joint.
SUMMARY OF THE INVENTION
[0003] The present invention seeks to provide a fastener assembly
that fastens to polyaxial pedicle screws that have already been
installed in spinal structure, as is described more in detail
hereinbelow. The fastener assembly of the present invention may be
used to fasten different elements to the pedicle screws, such as
but not limited to, fusion rods between adjoining vertebrae or
crossbars and other connections from the pedicle screws to any
suitable portion of the spine in the patient.
[0004] The present invention provides the possibility of connecting
with cross connectors to fusion systems directly to the pedicle
screw and not between the fusion rods as in current prior art
systems.
[0005] There is thus provided in accordance with an embodiment of
the invention a fastener assembly including an existing polyaxial
pedicle screw that has been previously installed in a spinal
structure, the polyaxial pedicle screw including a polyaxial head
to which a prosthetic member is secured, a fastening portion
fastened to the polyaxial head over the prosthetic member, and a
connector element that extends from the fastening portion, the
connector element being connected to another spinal structure.
[0006] In accordance with an embodiment of the invention the
fastening portion includes a wedge ring and the connector element
includes a conical ring into which the wedge ring fits, the
connector element including a connecting member that extends from
the conical ring, wherein the wedge ring is sized to fit over the
polyaxial head and the conical ring wedges the wedge ring onto the
polyaxial head.
[0007] Further in accordance with an embodiment of the invention
the wedge ring has a conical periphery with a top surface that has
a larger outer diameter than a bottom surface thereof, and the
conical ring has a top surface with a larger inner diameter than a
bottom surface thereof, the larger outer diameter not being greater
than the larger inner diameter. A plurality of grooves may be
formed in the conical periphery of the wedge ring. One or more of
the grooves may be open at the top surface and closed at the bottom
surface and one or more other grooves may be closed at the top
surface and open at the bottom surface.
[0008] In accordance with another embodiment of the invention the
fastening portion includes a closed ring and the connector element
includes a connecting member that extends from the closed ring, and
wherein the existing polyaxial pedicle screw includes a first
mechanical fastener fastened to the polyaxial head, wherein the
closed ring is placed over the first mechanical fastener such that
the first mechanical fastener protrudes through the closed ring,
and further including a second mechanical fastener that fastens to
the first mechanical fastener and is tightened against the closed
ring.
[0009] In accordance with yet another embodiment of the invention
the fastening portion includes an open ring that fits over the
polyaxial head and a mechanical fastener that fastens end portions
of the open ring towards each other so as to clamp the open ring
onto the polyaxial head, and the connector element includes a
connecting member that extends from the open ring. The end portions
of the open ring can be angled at an acute angle with respect to a
top surface of the open ring.
[0010] There is also provided in accordance with an embodiment of
the invention a method including fastening a fastening assembly to
a polyaxial head of an existing polyaxial pedicle screw that has
been previously installed in a spinal structure, a prosthetic
member being secured to the polyaxial head, wherein the fastening
assembly includes a fastening portion fastened to the polyaxial
head over the prosthetic member and a connector element that
extends from the fastening portion, and connecting the connector
element to another spinal structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention will be understood and appreciated
more fully from the following detailed description taken in
conjunction with the drawings in which:
[0012] FIG. 1 is a simplified pictorial illustration of a fastener
assembly, constructed and operative in accordance with an
embodiment of the present invention, showing two such fastener
assemblies with wedge rings and connector elements secured to
polyaxial pedicle screw heads that have previously been installed
in the left and right sides of vertebra;
[0013] FIGS. 2A and 2B are partially sectional illustrations of the
wedge ring and connector element of FIG. 1;
[0014] FIG. 3A is an exploded illustration of the wedge ring, the
connector element and a fastening tool used to secure the fastener
assembly on an existing polyaxial pedicle screw, in accordance with
an embodiment of the present invention;
[0015] FIG. 3B is a pictorial illustration of the wedge ring and
connector element mounted in the fastening tool;
[0016] FIGS. 3C and 3D are pictorial illustrations of the fastening
tool with the wedge ring and connector element placed over the
existing polyaxial pedicle screw;
[0017] FIGS. 3E and 3F are pictorial illustrations of using the
fastening tool to secure the fastening assembly of FIG. 1 on to the
existing polyaxial pedicle screw;
[0018] FIG. 4 is a simplified pictorial illustration of a fastener
assembly, constructed and operative in accordance with another
embodiment of the present invention, showing two such fastener
assemblies with closed rings and connector elements secured to
polyaxial pedicle screw heads that have previously been installed
in the left and right sides of vertebra;
[0019] FIG. 5 is a partially sectional illustration of the closed
ring and connector element of FIG. 4;
[0020] FIG. 6A is a pictorial illustration of fastening a set screw
of the fastener assembly of FIG. 4 on an existing polyaxial pedicle
screw, in accordance with an embodiment of the present
invention;
[0021] FIG. 6B is a pictorial illustration of placing the connector
element of the fastener assembly of FIG. 4 on the set screw;
[0022] FIGS. 6C and 6D are pictorial illustrations of a nut of the
fastener assembly of FIG. 4 mounted in a fastening tool used to
secure the fastener assembly on an existing polyaxial pedicle
screw, in accordance with an embodiment of the present
invention;
[0023] FIG. 6E is a pictorial illustration of feeding a torque
handle through a counter torque handle of the fastening tool;
[0024] FIG. 6F is a pictorial illustration of using the fastening
tool to secure the fastening assembly of FIG. 4 on to the existing
polyaxial pedicle screw;
[0025] FIG. 7 is a simplified pictorial illustration of a fastener
assembly, constructed and operative in accordance with yet another
embodiment of the present invention, showing two such fastener
assemblies with open rings and connector elements secured to
polyaxial pedicle screw heads that have previously been installed
in the left and right sides of vertebra;
[0026] FIG. 8 is a more detailed illustration of the open ring and
connector element of FIG. 7;
[0027] FIG. 9A is a pictorial illustration of fastening a set screw
of the existing polyaxial pedicle screw while the fastener assembly
of FIG. 7 is mounted on the existing polyaxial pedicle screw, in
accordance with an embodiment of the present invention;
[0028] FIG. 9B is a pictorial illustration of a tool used to fasten
the set screw of the existing polyaxial pedicle screw;
[0029] FIG. 9C is a pictorial illustration of aligning the fastener
assembly of FIG. 7 on the existing polyaxial pedicle screw, in
accordance with an embodiment of the present invention;
[0030] FIG. 9D is a pictorial illustration of a tool used to align
the fastener assembly of FIG. 7 on the existing polyaxial pedicle
screw; and
[0031] FIG. 9E is a pictorial illustration of tightening a set
screw of the fastener assembly of FIG. 7 on the existing polyaxial
pedicle screw.
DETAILED DESCRIPTION OF EMBODIMENTS
[0032] Reference is now made to FIG. 1, which illustrates a
fastener assembly 10, constructed and operative in accordance with
a non-limiting embodiment of the present invention.
[0033] Fastener assembly 10 includes one or more existing polyaxial
pedicle screws 12 (in the illustrated embodiment left and right
screws are shown) that have been previously installed in a spinal
structure (e.g., pedicles, articular processes, etc.). The
polyaxial pedicle screw 12 includes a polyaxial head 14 to which a
prosthetic member 16 is secured. In the non-limiting illustrated
embodiment, prosthetic member 16 are the prongs of a TOPS (total
posterior spine implant) brand spinal prosthesis, commercially
available from the present assignee and described in US Patent
7011685, the disclosure of which is incorporated herein by
reference.
[0034] Reference is now made to FIGS. 2A and 2B. A set screw 22 is
screwed in the female threads of polyaxial head 14 and clamps down
on prosthetic member 16. A fastening portion 18 (described more in
detail below) is fastened to the polyaxial head 14 over the
prosthetic member 16. A connector element 20 extends from fastening
portion 18. As seen in FIG. 1, connector element 20 is connected to
another spinal structure (e.g., adjacent lumbar vertebra).
[0035] In accordance with an embodiment of the invention, fastening
portion 18 includes a wedge ring 24 and connector element 20
includes a conical ring 26 into which wedge ring 24 fits. Connector
element 20 includes a connecting member 28 that extends from
conical ring 26, such as a rod, bar, plate and the like. Wedge ring
24 is sized to fit over polyaxial head 14 and conical ring 26
wedges wedge ring 24 onto polyaxial head 14.
[0036] As seen in FIG. 2B, wedge ring 24 has a conical periphery
with a top surface that has a larger outer diameter than a bottom
surface thereof, and conical ring 26 has a top surface with a
larger inner diameter than a bottom surface thereof, the larger
outer diameter of wedge ring 24 not being greater than the larger
inner diameter of conical ring 26. As seen in FIG. 3A, a plurality
of grooves 30 may be formed in the conical periphery of wedge ring
24. One or more of the grooves 30 may be open at the top surface
and closed at the bottom surface and one or more other grooves 30
may be closed at the top surface and open at the bottom
surface.
[0037] The fastener assemblies of the present invention may be
constructed of any suitable, rigid, medically safe material, such
as but not limited to, stainless steel alloy (e.g., AISI 316L),
titanium or titanium alloy or chrome cobalt alloy, PEEK, shape
memory alloys or polymers, and any combination thereof.
[0038] Reference is now made to FIGS. 3A-3F, which illustrate
installing wedge ring 24 and connector element 20 on the pedicle
screw 12.
[0039] A fastening tool 32 is used to secure the fastener assembly
on the existing polyaxial pedicle screw. FIGS. 3A and 3B show wedge
ring 24 and connector element 20 inserted in jaws of fastening tool
32. FIGS. 3C and 3D show fastening tool 32 with wedge ring 24 and
connector element 20 placed over the existing polyaxial pedicle
screw 14. The fastening tool 32 has an alignment indicator 34 that
indicates the proper alignment of connector element 20 with the
existing prosthetic member 16.
[0040] FIGS. 3E and 3F show using the fastening tool 32 to secure
fastening assembly 10 on to the existing polyaxial pedicle screw
10. Handles 36 of fastening tool 32 may be squeezed so that conical
ring 26 wedges wedge ring 24 onto polyaxial head 14 as described
above with reference to FIGS. 2A-2B.
[0041] The set screw of the existing pedicle screw may be left
loose or loosened somewhat during installation of the fastener
assembly on the existing polyaxial pedicle screw and afterwards
tightened to the recommended torque.
[0042] Reference is now made to FIGS. 4 and 5. In accordance with
another embodiment of the invention the fastening portion of the
fastening assembly includes a closed ring 40 and the connector
element includes a connecting member 42 that extends from closed
ring 40. The existing polyaxial pedicle screw 12 includes a first
mechanical fastener 44 (such as but not limited to, an elongate set
screw with a central through hole) fastened to polyaxial head 14.
Closed ring 40 is placed over the first mechanical fastener 44 such
that the first mechanical fastener 44 protrudes through closed ring
40. A second mechanical fastener 46 (such as but not limited to, a
nut) fastens to the first mechanical fastener 44 and is tightened
against closed ring 40, thereby securing the fastening portion of
the fastening assembly to the existing polyaxial pedicle screw
12.
[0043] Reference is now made to FIGS. 6A-6F. In FIG. 6A, a tool 45
is used to screw the first mechanical fastener 44 on the polyaxial
head 14 against the prosthetic member 16. In FIG. 6B, the closed
ring 40 of the connector element is placed over first mechanical
fastener 44 (first mechanical fastener 44 goes through the hole of
the closed ring 40). The first mechanical fastener 44 may be
further tightened a little at this time.
[0044] FIGS. 6C and 6D illustrate second mechanical fastener 46
mounted in a fastening tool (torque handle tool) 47 used to secure
the fastener assembly on the existing polyaxial pedicle screw. FIG.
6E illustrates feeding the torque handle tool 47 through a counter
torque handle 48. As seen in FIG. 6F, the counter torque handle 48
is used to hold the fastening assembly in proper alignment on the
existing polyaxial pedicle screw 12. Torque handle tool 47 is used
to tighten second mechanical fastener 46 against closed ring 40,
thereby securing the fastening portion of the fastening assembly to
the existing polyaxial pedicle screw 12.
[0045] Reference is now made to FIGS. 7 and 8. In accordance with
yet another embodiment of the invention the fastening portion
includes an open ring 50 that fits over the polyaxial head 14 and a
mechanical fastener 52 that fastens end portions 54 of the open
ring 50 towards each other so as to clamp the open ring 50 onto the
polyaxial head 14. The connector element includes a connecting
member 56 that extends from open ring 50. The end portions 54 of
the open ring 50 can be angled at an acute angle with respect to a
top surface of the open ring 50.
[0046] Reference is now made to FIGS. 9A-9E. In FIG. 9A, a
fastening tool 58 (also shown in FIG. 9B) is used to fasten the set
screw of the existing polyaxial pedicle screw while the fastener
assembly of FIG. 7 is mounted on the existing polyaxial pedicle
screw.
[0047] In FIG. 9C, a dedicated alignment tool 60 (also shown in
FIG. 9D) is used to align the fastener assembly of FIG. 7 on the
existing polyaxial pedicle screw 12.
[0048] In FIG. 9E, a tightening tool 62 is used to tighten the
mechanical fastener of the fastener assembly of FIG. 7 so as to
clamp the open ring 50 onto the polyaxial head 14.
[0049] It is appreciated that various features of the invention
which are, for clarity, described in the contexts of separate
embodiments, may also be provided in combination in a single
embodiment. Conversely, various features of the invention which
are, for brevity, described in the context of a single embodiment,
may also be provided separately or in any suitable
subcombination.
* * * * *