U.S. patent application number 14/370963 was filed with the patent office on 2015-01-01 for ratcheted spinal devices.
The applicant listed for this patent is APIFIX LTD.. Invention is credited to Uri Arnin.
Application Number | 20150005824 14/370963 |
Document ID | / |
Family ID | 48782067 |
Filed Date | 2015-01-01 |
United States Patent
Application |
20150005824 |
Kind Code |
A1 |
Arnin; Uri |
January 1, 2015 |
RATCHETED SPINAL DEVICES
Abstract
A spinal device (10) including a variable-length member (12)
including a ratchet mechanism (14) that has an operative
configuration that allows a change in length of the variable-length
member (12) in one direction and prevents a change in length of the
variable-length member (12) in an opposite direction, wherein the
variable-length member (12) includes polyaxial-joint attachment
members (32) for attachment to bone, which permit pivoting movement
of the attachment members (32) about more than one pivoting axis,
characterised by a force applicator (40) operative to adjust or
advance the ratchet mechanism (14).
Inventors: |
Arnin; Uri; (Tivon,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
APIFIX LTD. |
Misgav |
|
IL |
|
|
Family ID: |
48782067 |
Appl. No.: |
14/370963 |
Filed: |
January 7, 2013 |
PCT Filed: |
January 7, 2013 |
PCT NO: |
PCT/US2013/020453 |
371 Date: |
July 8, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61631667 |
Jan 9, 2012 |
|
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|
61690835 |
Jul 6, 2012 |
|
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61743418 |
Sep 4, 2012 |
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Current U.S.
Class: |
606/258 |
Current CPC
Class: |
A61F 2/4455 20130101;
A61B 17/7014 20130101; A61B 17/7001 20130101; A61B 17/7076
20130101; A61F 2/4425 20130101 |
Class at
Publication: |
606/258 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Claims
1. A spinal device comprising: a variable-length member comprising
a ratchet mechanism that has an operative configuration that allows
a change in length of said variable-length member in one direction
and prevents a change in length of said variable-length member in
an opposite direction, wherein said variable-length member
comprises polyaxial-joint attachment members for attachment to
bone, which permit pivoting movement of said attachment members
about more than one pivoting axis, and a force applicator operative
to adjust or advance said ratchet mechanism.
2. The spinal device to claim 1, wherein said force applicator
comprises a cam which has a tooth that engages a ratchet rack of
said ratchet mechanism.
3. The spinal device according to claim 1, comprising a pair of
said spinal devices and a connector assembly that forms a jointed
connection between said spinal devices that permits multiple
degree-of-freedom movement of said spinal devices.
4. A spinal device comprising: variable-length members each
comprising a ratchet mechanism that has an operative configuration
that allows a change in length of each of said variable-length
member in one direction and prevents a change in length of each of
said variable-length member in an opposite direction, wherein each
of said variable-length member comprises polyaxial-joint attachment
members for attachment to bone, which permit pivoting movement of
said attachment members about more than one pivoting axis, and a
connector assembly that forms a jointed connection between said
variable-length members that permits multiple degree-of-freedom
movement of said variable-length members.
5. The spinal device according to claim 4, wherein said connector
assembly comprises a bolt which passes through a first hinge member
and a second hinge member adjacent said first hinge member, and
pivot pins that pivotally connect said spinal devices to said first
hinge member and said second hinge member.
6. The spinal device according to claim 5, wherein said connector
assembly permits rotation about a longitudinal axis of said bolt,
and independently about a longitudinal axis of each pivot pin,
which are perpendicular to the longitudinal axis of said bolt.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to spinal implants
and prostheses, and particularly to spinal implants having ratchet
mechanisms, such as a spinal implant with joints that permit
movement in different degrees of freedom, or a spinal implant with
a force applicator to control a ratchet mechanism.
BACKGROUND OF THE INVENTION
[0002] Scoliosis is a spinal deformity affecting many people.
Current surgical treatment involves affixing long fusion rods to
the spine by pedicle screws. The rod system is intended to force
the deformed spine into a more healthy position. Other spinal
disorders which are often treated by fusion include hyperkyphosis
and hyperlordosis.
[0003] As an alternative to fusion, PCT Patent Application
PCT/US2011/035278 of the same inventor describes improved spinal
devices that can be lengthened or shortened using a ratchet
mechanism. The devices have a variable-length member that can be
connected to standard pedicle screws as well as to other spinal
rods, using appropriate connectors.
SUMMARY OF THE INVENTION
[0004] The present invention seeks to provide further improved
spinal devices.
[0005] In one embodiment, the spinal device is in the form of a
spinal rod (the term rod, or rod assembly, refers to one or more
elongate components that together function as a rod and which do
not necessarily have a cylindrical shape but can also be bars and
other shapes) that can be lengthened or shortened using a ratchet
mechanism. The rod is a variable-length member that can be
connected to standard pedicle screws as well as to other spinal
rods, using appropriate connectors. The variable-length member can
also be directly connected to, or be supported by, bony elements of
the spine.
[0006] In one embodiment of the invention, the device can be set to
three different configurations:
[0007] a. Ratchet mechanism active and the variable-length member
(rod) can change in length (extend or contract) in one
direction.
[0008] b. Ratchet mechanism not active and the variable-length
member can move in opposite directions corresponding to the
extending and contracting directions.
[0009] c. Locked position, wherein the length of the
variable-length member is fixed.
[0010] In an embodiment of the invention, the selection of these
configurations can be done by rotating an internal element of the
assembly. For example, the rotation of the internal element can be
done using a worm gear mechanism. The worm gear can be activated by
a shaft, through a percutaneous procedure or by an implantable
mechanism such as an electric motor, magnet arrangement or other
means known to those skilled in the art.
[0011] In another embodiment of the present invention, the
variable-length member can have two portions with different
rigidity. For example, the variable-length member can have a
flexible portion (e.g., when the ratchet is built such that the rod
can be only shortened) like a flexible cable, a rope, a flexible
mechanical joint and other means known to those skilled in the
art.
[0012] In another embodiment of the invention, useful when the rod
is supported directly by bone structure of the spine, the hook
holding against the bone can have a second hook to fix it to the
optimal position.
BRIEF DESCRIPTION OF DRAWINGS
[0013] The present invention will be understood and appreciated
more fully from the following detailed description, taken in
conjunction with the drawings in which:
[0014] FIG. 1 is a simplified pictorial illustration of a ratcheted
spinal device, constructed and operative in accordance with a
non-limiting embodiment of the invention;
[0015] FIG. 2 is a simplified pictorial illustration of a ratchet
mechanism of the ratcheted spinal device of FIG. 1;
[0016] FIG. 3 is a simplified illustration of a force applicator
that can adjust or advance the ratchet mechanism of the ratcheted
spinal device of FIG. 1;
[0017] FIG. 4 is a simplified pictorial illustration of a spinal
device, including two rod assemblies that are connected between
three vertebrae with three bone screws, constructed and operative
in accordance with a non-limiting embodiment of the present
invention, wherein there are connector assemblies that permit
multiple degree-of-freedom movement;
[0018] FIG. 5 is a simplified top view illustration of one
preferred embodiment of the connector assembly, in accordance with
an embodiment of the present invention;
[0019] FIG. 6A is a simplified cross-sectional illustration of the
embodiment of FIG. 5; and
[0020] FIG. 6B is a simplified cross-sectional illustration of a
modified version of the embodiment of FIG. 5.
DETAILED DESCRIPTION OF EMBODIMENTS
[0021] Reference is now made to FIGS. 1-3, which illustrates a
ratcheted spinal device 10, constructed and operative in accordance
with another non-limiting embodiment of the invention.
[0022] The ratcheted spinal device 10 includes a variable-length
member 12. In the illustrated embodiment, the variable-length
member 12 is a rod. The term "rod" encompasses any slender element
of any size and cross-sectional shape, such as but not limited to,
a rod, bar, wire and the like.
[0023] As similarly described in PCT Patent Application
PCT/US2011/035278, spinal device 10 includes a ratchet mechanism 14
(FIG. 2), which has an operative configuration that allows a change
in length of variable-length member 12 in one direction and
prevents a change in length of the variable-length member 12 in an
opposite direction. Ratchet mechanism 14 has ratchet teeth 16 (FIG.
3; also called ratchet rack 16) formed along an axial portion of
variable-length member 12, and a pawl 18 (FIGS. 2-3) arranged to
catch on one of the teeth 16. Pawl 18 extends from a controller
element 20 (FIG. 2) mounted about a pivot 22 (FIG. 2) and provided
with an eccentric cam 24 (FIGS. 2-3). Rotation of eccentric cam 24
moves pawl 18 to one of three positions: a) in ratchet engagement
with teeth 16 so that variable-length member 12 can incrementally
move in one direction, b) in locked engagement with teeth 16 so
that variable-length member 12 cannot move at all, and c) moved out
of engagement with teeth 16 so that variable-length member 12 can
move in both directions freely.
[0024] As seen in FIG. 1, one end 23 of variable-length member 12
is arranged to linearly move through an aperture 28 formed in a
housing 30. Variable-length member 12 includes two polyaxial-joint
attachment members 32. Both polyaxial-joint attachment members 32
are used to attach device 10 to available bone structure of the
spine.
[0025] In contradistinction to PCT Patent Application
PCT/US2011/035278, in the present invention, spinal device 10
includes a force applicator 40 to control ratchet mechanism 14.
Force applicator 40 includes, without limitation, a cam 42 which
has a tooth 44 (FIG. 3). The head 46 of cam 42 is shown in FIG. 2
(e.g., hexagonal head); head 46 is not shown for simplicity in FIG.
3. By turning head 46 with a suitable tool, such as a wrench (not
shown), in the clockwise direction of FIG. 3, the tooth 44 of cam
42 forcefully moves ratchet rack 16 (upwards in the sense of FIG.
3), so that the tooth in which pawl 18 is engaged moves out of
engagement with pawl 18 and the next lower tooth of ratchet rack 16
moves into engagement with pawl 18. Accordingly, force applicator
40 adjusts or advances the ratchet mechanism 14.
[0026] Reference is now made to FIG. 4, which illustrates a spinal
device 50, in accordance with an embodiment of the present
invention.
[0027] In the illustrated embodiment, spinal device 50 includes two
rod assemblies 52 that are connected between three vertebrae 49
with three bone screws 54. The rod assemblies 52 may be
constructed, without limitation, as ratcheted spinal devices 10 or
other spinal devices. Connector assemblies 56 form jointed
connections between rod assemblies 52. Connector assemblies 56
permit multiple degree-of-freedom movement of rod assemblies 52
(e.g., variable-length members 12), as will be explained below.
[0028] It is noted that any number of vertebrae can be selected,
since the design of the system is modular. It is also noted that
the middle jointed connection of the two rod assemblies 52 does not
have to be connected to any vertebra, meaning one or more vertebrae
can be skipped, depending on the application. In the drawing
figure, bone screws 54 are inserted in the pedicles, but other
insertion locations can be used.
[0029] Reference is now made to FIGS. 5 and 6A, which illustrate
one preferred embodiment of the connector assembly 56, in
accordance with an embodiment of the present invention.
[0030] Connector assembly 56 includes a bolt 58 (e.g., a central
threaded bolt) having a head 60, and which passes through a hole
formed in a first hinge member 62 and a second hinge member 64,
which may lie on top of, or be adjacent to, first hinge member 62.
Each hinge member is formed with a receiver 66 (FIG. 6A) for
receiving therein a pivot pin 68 (FIG. 5). One of the pivot pins 68
is pivotally received in an end 70 of one of the rod assemblies 52,
and the other pivot pin 68 is pivotally received in an end 72 of
another of the rod assemblies 52 (FIG. 5). Thus adjacent rod
assemblies 52 can pivot with respect to one another by means of
connector assembly 56. A locking element 74 (such as a nut) secures
pins 68 in place (FIG. 6A). Another locking element 76 (such as a
nut) is threaded on the end of threaded bolt 58 to complete the
assembly (FIG. 6A).
[0031] FIG. 6B illustrates a variation of the embodiment of FIG.
6A. Like elements are designated by like numerals. The main
differences are the shape of locking element 74 and the receiver 66
of the first hinge member 62 has a closed aperture instead of the
open aperture of FIG. 6A. Other variations are also possible within
the scope of the invention.
[0032] Connector assemblies 56 permit multiple degree-of-freedom
movement of rod assemblies 52. Rotation is permissible about the
longitudinal axis of central threaded bolt 58, and independently
about the longitudinal axis of each pin 68, which are perpendicular
to the longitudinal axis of central threaded bolt 58.
* * * * *