U.S. patent application number 13/487015 was filed with the patent office on 2012-09-20 for rod reducer.
Invention is credited to Laszlo Garamszegi.
Application Number | 20120239097 13/487015 |
Document ID | / |
Family ID | 38791264 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120239097 |
Kind Code |
A1 |
Garamszegi; Laszlo |
September 20, 2012 |
ROD REDUCER
Abstract
A rod reducer is adapted for inserting a rod into position
within an orthopedic device. The rod reducer is configured for use
with one hand and does not obstruct the surgeon's view of the
surgical field during use.
Inventors: |
Garamszegi; Laszlo; (Mission
Viego, CA) |
Family ID: |
38791264 |
Appl. No.: |
13/487015 |
Filed: |
June 1, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11804723 |
May 18, 2007 |
8192438 |
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13487015 |
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60801339 |
May 18, 2006 |
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Current U.S.
Class: |
606/86A |
Current CPC
Class: |
A61B 17/7086 20130101;
A61B 17/7001 20130101 |
Class at
Publication: |
606/86.A |
International
Class: |
A61B 17/56 20060101
A61B017/56 |
Claims
1. A surgical instrument for reducing a rod toward a bone fastener,
comprising: an engaging member extending between a proximal end and
a distal end, a distal portion of the engaging member adapted to
receive a portion of the rod therein and further adapted to engage
a coupling element coupled to the bone fastener; a reducing member
movably disposed about the engaging member, the reducing member
having a distal end; an actuator assembly mechanically coupled to
both the engaging member and to the reducing member, wherein the
actuator assembly actuates to move the reducing member distally
with respect to the engaging member such that the distal end of the
reducing member contacts the rod to move the rod toward the bone
fastener; and a handle adapted to actuate the actuator assembly,
wherein the engaging member and the reducing member extend along a
longitudinal axis and wherein the entire handle is offset from the
longitudinal axis.
2. An instrument as in claim 1, wherein the entire handle is offset
to one side of the longitudinal axis.
3. An instrument as in claim 1, wherein the handle comprises a
first trigger element and a second trigger element that are
pivotally coupled to the engaging member and pivotally coupled to
the reducing member.
4. An instrument as in claim 1, wherein the engaging member defines
an internal shaft that extends along the longitudinal axis, the
internal shaft sized to receive a portion of a pedicle screw
assembly.
5. An instrument as in claim 1, wherein the handle includes a
ratchet mechanism adapted to fix the position of the engaging
member relative to the reducing member.
6. An instrument as in claim 1, wherein the actuator assembly is
pivotally coupled to the engaging member and pivotally coupled to
the reducing member.
Description
REFERENCE TO PRIORITY DOCUMENT
[0001] This application claims priority of U.S. patent application
Ser. No. 11/804,723, filed May 18, 2007, titled "Rod Reducer", now
U.S. Pat. No. 8,192,438, which in turn claims priority to U.S.
Provisional Patent Application Ser. No. 60/801,339 filed May 18,
2006. Priority of the aforementioned filing date is hereby claimed
and the disclosure of the Provisional Patent Application is hereby
incorporated by reference in its entirety.
BACKGROUND
[0002] Disclosed is an instrument for moving a part of a surgical
implant into position or contact with another surgical implant
part. More particularly, disclosed is an instrument for securing a
spinal rod to a coupling element.
[0003] Spinal fixation surgical techniques use surgical implants
and/or mechanical immobilization to fuse two or more vertebral
bodies of the spinal column. Spinal fixation may also be used to
alter the alignment of adjacent vertebral bodies relative to one
another so as to change the overall alignment of the spinal
column.
[0004] One spinal fixation technique involves immobilizing the
spine using orthopedic stabilizing rods, or spine rods. A fixation
element, such as a spinal screw, can be threaded into a pedicle of
a vertebral body. The spinal screws are generally placed two per
vertebra on opposite sides of the spine and serve as anchors for
the spine rods. These rods are positioned generally parallel along
the length of the spine. Coupling elements adapted for receiving a
spine rod therethrough are then used to join the spine rods to the
pedicle screws. The spine rod is then held into a seat of the
coupling element by way of a set screw or fastener. This process is
also known as rod "reduction."
[0005] Rod reduction is performed by a surgeon typically using a
rod reducing tool to create the necessary pushing and/or pulling
forces on the implanted screw and rod. Surgeons can encounter
considerable difficulty using these instruments. Many instruments
require the use of two hands or have cumbersome mechanisms for
urging rods into place. Other limitations of current rod reducing
tools include problems with visualization of the surgical field.
Handles and triggers used in some instruments block the surgeon's
view of the field leading to errors and time lost during the
procedure. Still other instruments have a multitude of moving parts
with numerous connection points, which can fail as well as add to
the cost of manufacturing.
SUMMARY
[0006] There is a need for a rod reducer for inserting a rod into
position within an orthopedic device that is easy to use with one
hand and does not obstruct the surgeon's view of the surgical
field. There is a further need for the instrument to be robust,
simple in design and have fewer connecting parts to maintain a low
cost of manufacturing.
[0007] In one aspect, there is disclosed a surgical instrument for
reducing a rod toward a bone fastener, comprising: an engaging
member extending between a proximal end and a distal end, a distal
portion of the engaging member adapted to receive a portion of the
rod therein and further adapted to engage a coupling element
coupled to the bone fastener; a reducing member movably disposed
about the engaging member, the reducing member having a distal end;
an actuator assembly mechanically coupled to both the engaging
member and to the reducing member, wherein the actuator assembly
actuates to move the reducing member distally with respect to the
engaging member such that the distal end of the reducing member
contacts the rod to move the rod toward the bone fastener; and a
handle adapted to actuate the actuator assembly, wherein the
engaging member and the reducing member extend along a longitudinal
axis and wherein the entire handle is offset from the longitudinal
axis.
[0008] In another aspect, there is disclosed a surgical instrument
for reducing a rod toward a bone fastener, comprising: an engaging
member extending between a proximal end and a distal end, a distal
portion of the engaging member adapted to receive a portion of the
rod therein and further adapted to engage a coupling element
coupled to the bone fastener; a reducing member movably disposed
about the engaging member, the reducing member having a distal end;
an actuator assembly mechanically coupled to both the engaging
member and to the reducing member, wherein the actuator assembly
actuates to move the reducing member distally with respect to the
engaging member such that the distal end of the reducing member
contacts the rod to move the rod toward the bone fastener; and a
handle adapted to actuate the actuator assembly, wherein the
engaging member and the reducing member extend along a longitudinal
axis and wherein the longitudinal axis does not intersect any
portion of the handle.
[0009] Other features and advantages should be apparent from the
following description of various embodiments, which illustrate, by
way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows a perspective view of an exemplary instrument
for urging a spinal rod into a coupling element in a retracted
position.
[0011] FIG. 2 shows an exploded view of the instrument of FIG.
1.
[0012] FIG. 3 shows an enlarged, perspective view of a working end
of the instrument of FIG. 1 in a partially reduced position.
[0013] FIG. 4 shows a side, cross-sectional view of the instrument
of FIG. 1 in a retracted position.
[0014] FIG. 5A shows a perspective view of a coupling element.
[0015] FIG. 5B shows an enlarged, perspective view of the working
end of the instrument of FIG. 3 engaged with a rod and coupling
element shown in a retracted position.
[0016] FIG. 6 shows a side view of another embodiment of the
instrument.
DETAILED DESCRIPTION
[0017] FIG. 1 shows a perspective view of an exemplary instrument
100 for persuading a rod into a seat recess of an orthopedic device
or coupling element, such as a pedicle screw assembly. The
instrument 100 includes an inner longitudinal body 200, an outer
longitudinal body 300 and a handle or grip made up of a first
trigger element 400 and a second trigger element 500. It should be
appreciated that the instrument 100 is not limited to the
particular mechanical configuration shown in FIG. 1 and that the
configuration of the instrument 100 can be modified.
[0018] FIG. 2 shows an exploded view of the exemplary instrument
100 including the inner longitudinal body 200 (also referred to as
a reducing member), a spring 700, the outer longitudinal body 300
(also referred to as an engaging member), the first trigger element
400 and the second trigger element 500. The inner longitudinal body
200 is generally cylindrical and has a working end 210 and a
trigger end 212. In addition, the inner longitudinal body 200 is
generally hollow and defines a channel 215 extending longitudinally
through it from the working end 210 to the trigger end 212. The
trigger end 212 of the inner longitudinal body 200 includes an
aperture 217 through which an attachment element, such as a bolt or
screw or the like, may be inserted for attaching it to the second
trigger element 500 as described in more detail below. The working
end 210 is adapted to mate with a rod. In this regard, the working
end 210 can be forked and made up of a pair of opposing prongs 216,
218.
[0019] As best shown in FIG. 3, the prongs 216, 218 each have an
interior wall which define catches 205 that are adapted to mate
with at least a portion of a pedicle screw assembly. For example,
the catches 205 can have a shape that complements or corresponds to
the shape of the outer surface of a receiver element or coupling
element 220 (see FIG. 5A) of a pedicle screw assembly. The receiver
element is sometimes referred to as a yoke. The prongs 216, 218 can
be substantially identically configured. They are of a size, shape
and depth that allows insertion of a coupling element 220 between
them. The prongs 216, 218 are rigid, but sufficiently elastic such
that application of force can separate the prongs in order to
insert a coupling element 220 between them. The prongs 216, 218
grip the coupling element 220 via spring motion and also due to
interaction between the catches 205 and grooves 222 present on the
coupling element 220. The inner longitudinal body 200 need not have
prongs, but can also be formed from a substantially solid body
having an appropriately-shaped socket at its working end 210 for
engaging the coupling element 220. The inner longitudinal body 200
can be configured to mate with or couple with other portions of the
coupling element 220.
[0020] As best shown in FIG. 2, the outer longitudinal body 300 is
generally cylindrical and has a working end 310 and a trigger end
312. The working end 310 includes a pair of opposed notches 305.
Near the trigger end 312, the outer longitudinal body 300 includes
a flange 314. The outer longitudinal body 300 is generally hollow
and defines a channel extending longitudinally through it from the
working end 310 to the trigger end 312. The outer longitudinal body
300 is sized and shaped to receive the inner longitudinal body 200
therein.
[0021] As shown in FIG. 4, when assembled, the inner longitudinal
body 200 is encircled by the spring 700 or other biasing element
such that one end of the spring 700 abuts a flange 214 near the
working end 210 of the inner longitudinal body 200. The force of
the spring 700 results in the instrument 100 being biased toward a
retracted position. The spring 700 is disposed between the flange
214 near the working end 210 of the inner longitudinal body 200 and
the flange 314 near the trigger end 312 of the outer longitudinal
body 300. When not in use, the spring 700 is in the expanded
position such that the working end 310 of the outer longitudinal
body 300 is positioned away from the working end 210 of the inner
longitudinal body 200. For example, the working end 310 of the
outer longitudinal body 300 can be at a point furthest away from
the working end 210 of the inner longitudinal body 200.
[0022] With reference still to FIG. 4, the inner longitudinal body
200 is slidably disposed within the channel 315 of the outer
longitudinal body 300. The channel 215 of the inner longitudinal
body 200 and the channel 315 of the outer longitudinal body 300
together form a working channel of the instrument 100 which extends
along the longitudinal axis C between the trigger ends 212, 312 and
working ends 210, 310. The working channel can be used to feed
additional parts or tools to the site of the surgical implant.
Although the working channel of the instrument 100 is shown as
having a generally cylindrical shape, it is to be understood that
the instrument working channel can have any appropriate shape. The
inner longitudinal body 200 and outer longitudinal body 300 also
both extend along the axis C.
[0023] The length of the working channel as well as the reduction
distance of the instrument 100 can also vary. This allows the
surgeon to select an instrument 100 having an extension/passage of
appropriate length for the distance of rod reduction that is
desired. The inner and outer longitudinal bodies 200, 300 are also
shaped such that contact between them is appropriate for being in
slideable communication. However, the spacing between the inner and
outer longitudinal bodies 200, 300 is minimized to limit the amount
of wobble or play between the two.
[0024] As mentioned, the instrument 100 has a grip that is made up
of a first trigger element 400 and a second trigger element 500
(best shown in FIG. 1). With reference to FIG. 1, the first trigger
element 400 includes a coupler, such as a ring 450, at one end that
couples or encircles the trigger end 312 of the outer longitudinal
body 300. The second trigger element 500 has a fork 520 in which
another coupler, such as a ring 550, is rotatably attached via an
attachment element 555. The ring 550 encircles the trigger end 212
of the inner longitudinal body 200 and is attached via the
attachment element 555 threaded through the aperture 217 located
near the trigger end 212 of the inner longitudinal body 200. The
ring 450 of the first trigger element 400 is disposed between the
flange 314 and the ring 550 of the second trigger element 400.
[0025] It should be noted that the use of attachment elements, such
as bolts and screws, in the construction of the instrument 100 are
at a minimum. This reduces the number of connection points and
thereby confers a more robust construction to the instrument. Most
parts are machined to connect and fit together as opposed to being
bolted or screwed together. The parts of the instrument 100 are
made of a sturdy, biocompatible material such as stainless steel
using standard fabrication techniques for medical grade
instruments. Other biocompatible materials are contemplated.
[0026] The second trigger element 500 is at an angle A from the
longitudinal axis C of the instrument 100. This offset of the
second trigger element 500 from the longitudinal axis C of the
instrument 100 allows for a substantially unimpeded view of the
surgical site by the operator during use. This is in contrast to
instruments commonly used in the art which are not offset from the
longitudinal axis of the instrument. Instruments where the handle
or actuator means are not offset block at least a part of the
surgeon's view of the surgical field. However, it should be
understood that angle A can be other angles such that the surgeon's
view of the surgical field is substantially unimpeded by the
instrument handles and trigger elements. In an embodiment, the
entire handle is offset from the axis C. The entire handle can be
offset to one side of the axis C. The handle can include an
elongate portion EP that extends laterally away from the axis C and
positions the entire handle in an offset position relative to the
axis C. The handle can be configures such that no portion of either
of the trigger elements 400 and 500 intersects the axis.
[0027] The instrument 100 can be used to urge a rod into a coupling
element, such as a coupling element of a pedicle screw assembly.
FIG. 5A shows an exemplary coupling element 220. The coupling
element 220 includes grooves 222 on its outer surface, threads 224
on its inner surface and an aperture 226 through which a fastener,
such as a pedicle screw, can be inserted. The fastener can be a
multi-axial or uni-axial screw, a hook, or other bone or tissue
engaging device. The coupling element 220 has slots in which the
rod can be positioned. The threads 224 are configured for a set
screw or the like (not shown) to be tightened over the rod securing
it in the coupling element 220.
[0028] FIG. 5B shows a rod R and coupling element 220 engaged at
the working end of the instrument 100 such as engaged to the member
200. The rod R rests within the notches 305 of the outer
longitudinal body 300. The coupling element 220 is shown within the
grip of the prongs 216, 218 of the inner longitudinal body 200. The
rod R can be any elongated implant element of any size or shape so
long as it can be secured to the coupling element 220.
[0029] With reference again to FIG. 1, the instrument 100 can
further include a ratchet mechanism 570. As described above, the
instrument 100 is biased in the retracted position such that the
working end 310 of the outer longitudinal body 300 is positioned
away from, such as at a point furthest away from, the working end
210 of the inner longitudinal body 200 by virtue of the force of
the spring 700 disposed between the flanges 314 and 214. As the
outer longitudinal body 300 slides longitudinally across the inner
longitudinal body 200 in the direction of arrow B (FIG. 4) to
reduce the rod, the spring 700 compresses between the flanges 314
and 214. The ratchet mechanism 570 is used to hold the instrument
100 in this reduced position.
[0030] With reference still to FIG. 1, the second trigger element
500 has a ratchet mechanism 570 and the first trigger element 400
has a connector 470. The teeth 575 of the ratchet mechanism 570
cooperate with the connector 470 as the trigger element 400 is
squeezed toward the trigger element 500 in the direction of arrow A
and the two are brought together. The teeth 575 can be step-wise
engaged with the connector 470. The outer longitudinal body 300 is
advanced in the direction of arrow B as successive teeth 575 engage
with the connector 470. As this process continues and the notch 305
of the outer longitudinal body 300 contacts the rod R, the rod R is
urged into position in the coupling element 220. The ratchet
mechanism 570 locks the position of the outer longitudinal body 300
with respect to the inner longitudinal body 200 and prevents
regression of the rod R back away from the coupling element 220 in
the direction opposite of arrow B. The operator thus is not
required to continue applying pressure to the trigger elements to
maintain position of the rod.
[0031] In operation, the user grasps the instrument 100 in one hand
at the first and second trigger elements. The coupling element 220
is engaged between the prongs 216, 218 of the inner longitudinal
body 200. The rod R is resting between the notches 305 and the
coupling element 220. The first trigger element 400 is moved or
squeezed toward the second trigger element 500 in the direction of
arrow A (see FIG. 1) around pivot point 430. The process can be a
single, continuous movement or alternatively can be step-wise due
to the use of a ratchet mechanism 570 as described above. The
displacement of the first trigger element 400 around pivot point
430 causes movement of the outer longitudinal body 300 slidably
over the inner longitudinal body 200 in the direction of arrow B.
As the outer longitudinal body 300 slides forward, the notches 305
connect with the rod R and urge the rod R in the direction of arrow
B. The coupling element 220 is held or gripped between the prongs
216, 218 at the working end 210 of the inner longitudinal body 200.
The rod R is urged or advanced into the recess or seat of the
coupling element 220. Outward movement of the prongs 216, 218 is
prevented due in part to the presence of the outer longitudinal
body 300 over the working end 210 of the inner longitudinal body
200.
[0032] Once the desired rod reduction is achieved, the rod R is
secured in place. To secure the rod in place, a fastener, such as a
set screw, can be inserted through the working channel of the
instrument 100. The set screw is tightened into the threads 224 of
the coupling element 220 by a driver or other tool similarly fed
through the working channel of the instrument 100.
[0033] The instrument 100 can release its grip by rotation to
disengage the catches 205 from the grooves 222 in the outer surface
of the coupling element 220. Force can be applied to the instrument
100 in the direction opposite of the secured rod R. This frees the
instrument 100 from its grip on the coupling element 220 while
leaving the secured rod R in place.
[0034] FIG. 6 shows a side view of another embodiment of the
instrument 100. This embodiment of the instrument 100 is
substantially similar to the previous embodiment. For example, the
instrument 100 includes an inner longitudinal body 200, an outer
longitudinal body 300 and a handle or grip made up of a first
trigger element 400 and a second trigger element 500. The outer
longitudinal body 300 includes a plurality of apertures or holes
along its length that communicate with an internal, elongate
channel. Like numerals refer to like parts with respect to the
previous embodiment of the instrument 100.
[0035] The previous embodiment of the instrument 100 included a
biasing element comprised of a spring 700 (FIGS. 2 and 4) that
provided a biasing force that urged the instrument toward a
retracted position. In the embodiment of FIG. 6, the spring 700 is
replaced by a biasing element comprised of one or more leaf springs
605 that are positioned between the triggers 400 and 500. The leaf
springs 605 provide a biasing force that urges the triggers 400 and
500 away from one another. Thus, the leaf springs 605 urge the
instrument toward a retracted position. It should be appreciated
that any of a variety of mechanisms or other means can be used to
urge the instrument toward the retracted position. Alternately, the
instrument is urged toward a non-retracted position.
[0036] Although embodiments of various methods and devices are
described herein in detail with reference to certain versions, it
should be appreciated that other versions, embodiments, methods of
use, and combinations thereof are also possible. Therefore, the
spirit and scope of the instrument should not be limited to the
description of the embodiments contained herein.
* * * * *