U.S. patent application number 11/861551 was filed with the patent office on 2009-03-26 for devices and methods for positioning a spinal fixation element.
This patent application is currently assigned to DePUY SPINE, INC.. Invention is credited to David Greg Anderson, Paul G. Beaudoin, Sara Dziedzic, Shawn D. Stad, Tony Tannoury.
Application Number | 20090082811 11/861551 |
Document ID | / |
Family ID | 40472536 |
Filed Date | 2009-03-26 |
United States Patent
Application |
20090082811 |
Kind Code |
A1 |
Stad; Shawn D. ; et
al. |
March 26, 2009 |
DEVICES AND METHODS FOR POSITIONING A SPINAL FIXATION ELEMENT
Abstract
Methods for delivering a spinal fixation element to a surgical
site are provided herein. More specifically, the method includes
delivering a plurality of percutaneous access devices to a
corresponding number of spinal locations, inserting a spinal
fixation element through tissue, and manipulating the element
through opposed sidewall openings formed in each access device. In
an exemplary embodiment, the method can be optimized for position
of large-scale fixation elements (e.g., greater than about 95 mm in
length). In addition, a manipulation instrument configured to
position such spinal fixation elements is also provided herein.
Inventors: |
Stad; Shawn D.; (Fall River,
MA) ; Anderson; David Greg; (Moorestown, NJ) ;
Tannoury; Tony; (Andover, MA) ; Beaudoin; Paul
G.; (Derry, NH) ; Dziedzic; Sara; (Dorchester,
MA) |
Correspondence
Address: |
NUTTER MCCLENNEN & FISH LLP
WORLD TRADE CENTER WEST, 155 SEAPORT BOULEVARD
BOSTON
MA
02210-2604
US
|
Assignee: |
DePUY SPINE, INC.
Raynham
MA
|
Family ID: |
40472536 |
Appl. No.: |
11/861551 |
Filed: |
September 26, 2007 |
Current U.S.
Class: |
606/250 ;
606/103 |
Current CPC
Class: |
A61B 17/7085 20130101;
A61B 17/7011 20130101; A61B 17/7032 20130101 |
Class at
Publication: |
606/250 ;
606/103 |
International
Class: |
A61B 17/58 20060101
A61B017/58 |
Claims
1. A method for delivering a spinal fixation element to a surgical
site, comprising: engaging a plurality of percutaneous access
devices to a corresponding number of spinal locations, each access
device being delivered to the respective spinal location via a
respective incision such that at least a first access device is
delivered via a first incision, each percutaneous access device
having a distal end disposed adjacent to a spinal anchor and a
proximal end positioned outside a patient's body; releasably
engaging a proximal end of a spinal fixation element to a
manipulation instrument; delivering a distal portion of the spinal
fixation element through the first incision; manipulating the
distal portion of the spinal fixation element through opposed
sidewall openings of the first percutaneous access device; guiding
the distal portion of the spinal fixation element through opposed
side wall openings of each percutaneous access device; placing the
spinal fixation element within the plurality of spinal anchors such
that at least a portion of the spinal fixation element resides
within each of the plurality of spinal anchors; and releasing the
spinal fixation element from the manipulation instrument following
the placing step.
2. The method of claim 1, wherein the spinal fixation element is a
rod.
3. The method of claim 1, wherein the spinal fixation element has a
length configured to provide a three-level spinal fixation.
4. The method of claim 1, wherein the spinal fixation element has a
length configured to provide at least a four-level spinal
fixation.
5. The method of claim 1, wherein three percutaneous access devices
are utilized.
6. The method of claim 1, wherein at least four percutaneous access
devices are utilized.
7. The method of claim 1, wherein the proximal end of at least one
percutaneous access device is closed.
8. The method of claim 1, wherein the proximal end of at least one
percutaneous access device is open.
9. The method of claim 1, wherein the releasably engaging step
comprises: disposing the proximal end of the spinal fixation
element within an opening formed in a distal portion of the
manipulation instrument; and securing the spinal fixation element
to the manipulation instrument by engaging a distal end of an
engagement element to a notch formed in a proximal portion of the
spinal fixation element, the engagement element being disposed
within a distal portion of the manipulation instrument.
10. The method of claim 9, wherein the releasing step comprises:
applying an actuation force to an actuator coupled to the
manipulation instrument wherein the actuation force disengages the
distal end of the engagement element from the notch formed in the
proximal portion of spinal fixation element.
11. A minimally invasive method for delivering a spinal fixation
element to a surgical site, comprising: inserting a plurality of
access devices into a body through a percutaneous incision for each
access device such that a proximal end of each access device is
positioned outside the body and a distal end engages a spinal
anchor disposed in a vertebra; engaging a proximal portion of a
spinal fixation element to a distal portion of a manipulation
instrument; inserting the spinal fixation element through one of
the percutaneous incisions for one of the access devices such that
a distal portion of the spinal fixation element is positioned
adjacent an outer portion of a first percutaneous access device;
manipulating the spinal fixation element such that the spinal
fixation element passes through the opposed sidewall openings of
each percutaneous access device; placing the spinal fixation
element in the plurality of spinal anchors such that at least a
portion of the spinal fixation element resides within each bone
anchor; and disengaging the spinal fixation element from the
manipulation instrument following the placing step.
12. The method of claim 11, wherein the spinal fixation element is
a rod.
13. The method of claim 11, wherein the spinal fixation element has
a length configured to provide a three-level spinal fixation.
14. The method of claim 11, wherein the spinal fixation element has
a length configured to provide at least a four-level spinal
fixation.
15. The method of claim 11, wherein the releasably engaging step
comprises: disposing the proximal end of the spinal fixation
element within an opening formed in a distal portion of the
manipulation instrument; and securing the spinal fixation element
to the manipulation instrument by engaging a distal end of an
engagement element to a notch formed in a proximal portion of the
spinal fixation element, the engagement element being disposed
within a distal portion of the manipulation instrument.
16. The method of claim 15, wherein the releasing step comprises:
applying an actuation force to an actuator coupled to the
manipulation instrument wherein the actuation force disengages the
distal end of the engagement element from the notch formed in the
proximal portion of spinal fixation element.
17. A method for delivering a spinal fixation element to a surgical
site, comprising: engaging a plurality of percutaneous access
devices to a corresponding number of spinal locations, each access
device being delivered to the respective spinal location via a
respective incision such that at least a first access device is
delivered via a first incision, each percutaneous access device
having a distal end disposed adjacent to a spinal anchor and a
proximal end positioned outside a patient's body; releasably
engaging a proximal portion of a spinal fixation element to a
distal portion of a manipulation instrument, the manipulation
instrument having a handle portion coupled to an elongate shaft via
an offset; delivering a distal portion of the spinal fixation
element through the first incision; manipulating the distal portion
of the spinal fixation element through opposed sidewall openings of
the first percutaneous access device; guiding the distal portion of
the spinal fixation element through opposed side wall openings of
each percutaneous access device; placing the spinal fixation
element within the plurality of spinal anchors such that at least a
portion of the spinal fixation element resides within the spinal
anchors; and releasing the spinal fixation element from the
manipulation instrument following the above placing step.
18. The method of claim 17, wherein a distal portion of the
elongate shaft is angled relative to a proximal portion of the
elongate shaft.
19. The method of claim 17, further comprising: contacting a distal
end of the manipulation instrument to a distal portion of a first
percutaneous access device, the distal end of the manipulation
instrument configured to prevent passage of the instrument through
the opposed side-wall openings, the contacting step performed prior
to the releasing step.
20. A device for releasably engaging a spinal fixation element and
positioning the element percutaneously into a spinal anchor,
comprising: a handle having a proximal end and a distal end; an
offset having a proximal end and a distal end, the proximal end of
the offset coupled to the distal end of the handle and the distal
end of the offset extending into an elongate shaft; and an opening
formed in the distal end of the elongate shaft, the opening being
configured to receive and releasably engage a proximal end of a
spinal fixation element.
21. The device of claim 20, wherein the distal portion of the
elongate shaft is configured to prevent passage of the shaft within
a sidewall opening of a percutaneous access device attached to a
spinal anchor.
22. The device of claim 20, further comprising: an actuator coupled
to the shaft, the actuator configured to release an engaged spinal
fixation element from the distal end of the device.
23. The device of claim 20, wherein a distal portion of the
elongate shaft is angled relative to a proximal portion of the
elongate shaft.
24. A device for releasably engaging a spinal fixation element and
positioning the element percutaneously into a plurality of spinal
anchors, comprising: a handle having a proximal end and a distal
end, the distal end of the handle being coupled to an elongate
shaft by an offset; a distal end of the elongate shaft having an
opening configured to receive a proximal end of a spinal fixation
element, the distal end also being configured to prevent passage of
the manipulation instrument through a side-wall opening of a
percutaneous access device; and an actuator coupled to the distal
shaft of the instrument, the actuator being in communication with
an engagement disposed within an inner lumen of the elongate shaft
and being capable of moving the engagement element into and out of
contact with a portion of the spinal fixation element disposed
within the opening of the elongate shaft thereby retaining or
releasing the spinal fixation element from the device upon
actuation.
25. The device of claim 24, wherein a distal portion of the
elongate shaft is angled relative to a proximal portion of the
elongate shaft.
Description
FIELD OF USE
[0001] Methods and devices are provided herein for use in spinal
surgery, and in particular to methods and devices for positioning a
spinal fixation element.
BACKGROUND
[0002] For a number of reasons, spinal fixation devices are used in
orthopedic surgery to align and/or fix a desired relationship
between vertebral bodies. Such devices typically include a spinal
fixation element, such as a relatively rigid fixation rod, that is
coupled to adjacent vertebrae by attaching the element to various
anchoring devices, such as hooks, bolts, wires, or screws. The
fixation elements can have a predetermined contour that has been
designed according to the properties of the target implantation
site, and once installed, the instrument holds the vertebrae in a
desired spatial relationship, either until desired healing or
spinal fusion has taken place, or for some longer period of
time.
[0003] Spinal fixation elements can be anchored to specific
portions of the vertebrae. Since each vertebra varies in shape and
size, a variety of anchoring devices have been developed to
facilitate engagement of a particular portion of the bone. Pedicle
screw assemblies, for example, have a shape and size that is
configured to engage pedicle bone. Such screws typically include a
threaded shank that is adapted to be threaded into a vertebra, and
a head portion having a rod-receiving element, usually in the form
of a U-shaped slot formed in the head. A set-screw, plug, or
similar type of fastening mechanism is used to lock the fixation
element, e.g., a spinal rod, into the rod-receiving head of the
pedicle screw. In use, the shank portion of each screw is threaded
into a vertebra, and once properly positioned, a rod is seated
through the rod-receiving member of each screw and the rod is
locked in place by tightening a cap or other fastener mechanism to
securely interconnect each screw and the fixation rod.
[0004] Recently, the trend in spinal surgery has been moving toward
providing minimally invasive devices and methods for implanting
spinal fixation devices. One such method, for example, is disclosed
in U.S. Pat. No. 6,530,929 of Justis et al. and it utilizes two
percutaneous access devices for implanting an anchoring device,
such as a spinal screw, into adjacent vertebrae. A spinal rod is
then introduced through a third incision a distance apart from the
percutaneous access sites, and the rod is transversely moved into
the rod-engaging portion of each spinal screw. The percutaneous
access devices can then be used to apply closure mechanisms to the
rod-engaging heads to lock the rod therein. While this procedure
offers advantages over prior art invasive techniques, the
transverse introduction of the rod can cause significant damage to
surrounding tissue and muscle. Moreover, the use of three separate
access sites can undesirably lengthen the surgical procedure, and
increase patient trauma and recovery time.
[0005] In general, current minimally invasive procedures have been
limited to the use of relatively short spinal fixation elements
(e.g., less than about 95 mm) thereby limiting the availability of
minimally invasive surgery in some spinal fusion procedures. For
example, a 95 mm spinal fixation element is typically limited to a
maximum of a three level fusion. Thus, there remains a need for
devices and methods capable of providing increased treatment
options.
SUMMARY
[0006] Methods and instruments for delivering a spinal fixation
element to a surgical site are provided herein. More specifically,
the various embodiments enable surgeons to perform high level
spinal fusions (traversing three vertebra, four vertebra, five
vertebra, etc.) by means of minimally invasive surgical procedures.
Thus, the methods and instruments can be configured to allow for
positioning of a large spinal fixation element (e.g., greater than
about 95 mm in length) within a plurality of spinal anchors engaged
to various spinal locations. Additionally, the disclosed surgical
procedures can be configured to minimize the number of incisions
thereby minimizing any tissue damage (and resulting patient
discomfort) associated with the procedure.
[0007] Various aspects of the method are provided herein. For
example, in one aspect, the method includes engaging a plurality of
percutaneous access devices to a corresponding number of spinal
locations. Each access device can be delivered to the respective
spinal location via a respective incisions such that, for example,
at least a first access device is delivered via a first incision.
Thus, the method can be configured to limit the number of required
incisions to the number of percutaneous access devices being
utilized in any given procedure. Each percutaneous access device
can include a distal end disposed adjacent to a spinal anchor and a
proximal end positioned outside a patient's body. The method next
includes delivering a distal portion of a spinal fixation element
through the first incision, manipulating the distal portion of the
spinal fixation element through opposed sidewall openings of the
first percutaneous access device, and guiding the spinal fixation
element through opposed sidewall openings of each percutaneous
access device. As such, the spinal fixation element can be
delivered through the percutaneous access devices from the outside
of the first device thereby eliminating the need to pass the
fixation element longitudinally along an inner lumen of the access
device. The method can further include placing the spinal fixation
element within the plurality of spinal anchors such that at least a
portion of the spinal fixation element resides within each of the
plurality of spinal anchors, and releasing the spinal fixation
element from the manipulation instrument following the placing
step.
[0008] As known to those of skill in the art, the spinal fixation
element can include any such element capable of providing the
desired spinal fusion. For example, in an exemplary embodiment, the
spinal fixation element is a fixation rod. While the spinal
fixation element can be of any desired length, in exemplary
embodiments, the length of the spinal fixation element is greater
than about 95 mm, greater than about 100 mm, etc. In general, the
length of the spinal fixation element is selected so as to achieve
the desired level of spinal fusion (e.g., across three vertebrae,
across four vertebra, across five vertebra, etc.).
[0009] As indicated, the method includes delivering a plurality of
percutaneous access devices to a corresponding number of spinal
locations. The number of percutaneous access devices can vary
depending on the procedure. For example, the method can utilize two
such devices, three such devices, four such devices, or more than
four such devices. Thus, the method can allow for a large number of
such devices to be utilized thereby allowing fusions of greater
levels and further allowing fusions spanning across various regions
of the spine.
[0010] The percutaneous access devices can be configured in various
manners. Generally, the devices include a distal end configured to
releasably engage a spinal anchor, and a proximal end positioned
outside of a patient's body. In an exemplary embodiment, the
proximal end of at least one (or all) of the percutaneous access
devices can be closed because the spinal fixation element is not
being delivered axially along an inner lumen of the device but
rather being delivered laterally through opposed sidewall openings.
As will be discussed, the use of a percutaneous access device
having a closed proximal end facilitates various downstream
steps.
[0011] The spinal fixation element can be delivered and/or
manipulated through the opposed sidewall openings of the various
percutaneous access devices in various manners. For example, in one
aspect, the method can include releasably engaging a proximal
portion of the spinal fixation element to a distal portion of a
manipulation instrument. As discussed below, the manipulation
instrument can be configured in various manners so as to facilitate
the delivery and positioning of a relatively large-scale spinal
fixation element at the surgical site. The method can further
include disengaging the spinal fixation element from the
manipulation instrument after the spinal fixation element passes
through the opposed sidewall openings of each percutaneous access
device. In one such embodiment, the releasably engaging step of the
method can include disposing the proximal end of the spinal
fixation element within an opening formed in a distal portion of
the manipulation instrument, and securing the spinal fixation
element to the manipulation instrument by engaging a distal end of
an engagement element to a notch formed in a proximal portion of
the spinal fixation element wherein the engagement element is
disposed in a distal portion of the manipulation instrument. Also,
the releasing step of the method can include applying an actuation
force to an actuator wherein the actuation force can disengage the
distal end of the engagement element from the notch formed in the
proximal portion of the spinal fixation element.
[0012] In another aspect, a minimally invasive method for
delivering a spinal fixation element to a surgical site is provided
which includes inserting a plurality of access devices into a body
through a percutaneous incision for each access device such that a
proximal end of each access device is positioned outside the body
and a distal end engages a spinal anchor disposed in a vertebra.
Next, the method can include inserting a spinal fixation element
through one of the percutaneous incisions for one of the access
devices such that a distal portion of the spinal fixation element
is positioned adjacent an outer portion of a first percutaneous
access device. Further, the method can include manipulating the
spinal fixation element such that the spinal fixation element
passes through the opposed sidewall openings of each percutaneous
access device. Once the spinal fixation element has been positioned
through the opposed sidewall openings of each percutaneous access
device, the method can further include placing the spinal fixation
element in the plurality of spinal anchors such that at least a
portion of the spinal fixation element resides within each bone
anchor, and disengaging the spinal fixation element from the
manipulation instrument following the placing step.
[0013] In another aspect, a method for delivering a spinal fixation
element to a surgical site is provided which includes engaging a
plurality of percutaneous access devices to a corresponding number
of spinal locations with each access device being delivered to the
respective spinal location via a respective incision such that at
least a first access device is delivered via a first incision
wherein each percutaneous access device can include a distal end
disposed adjacent to a spinal anchor and a proximal end positioned
outside a patient's body. The method can also include releasably
engaging a proximal portion of a spinal fixation element to a
distal portion of a manipulation instrument wherein the
manipulation instrument includes a handle portion coupled to an
elongate shaft via an offset. Further, the method can include
delivering a distal portion of the spinal fixation element through
the first incision, and manipulating the distal portion of the
spinal fixation element through opposed sidewall openings of the
first percutaneous access device. The method can also include
guiding the distal portion of the spinal fixation element through
opposed side wall openings of each percutaneous access device, and
placing the spinal fixation element within the plurality of spinal
anchors such that at least a portion of the spinal fixation element
resides within the spinal anchors. Further, the method can also
include releasing the spinal fixation element from the manipulation
instrument following the above placing step.
[0014] In addition to the various aspects of the method provided
above, an instrument for releasably engaging a spinal fixation
element and positioning the element percutaneously into a spinal
anchor is provided herein. In one such aspect, the instrument can
include a handle having a proximal end and a distal end. The
instrument can also include an offset having a proximal end and a
distal end wherein the proximal end of the offset is coupled to the
distal end of the handle and the distal end of the offset can
extend into an elongate shaft. Further, the instrument can includes
an opening formed in the distal end of the elongate shaft wherein
the opening is configured to receive and releasably engage a
proximal end of a spinal fixation element. Optionally, the distal
portion of the elongate shaft can be configured to prevent passage
of the shaft within a sidewall opening of a percutaneous access
device attached to a spinal anchor.
[0015] The instrument can include various other components and/or
features capable of facilitating placement and positioning of a
spinal fixation element. For example, in one embodiment, the
instrument can include an actuator coupled to the shaft wherein the
actuator is configured to release an engaged spinal fixation
element from the distal end of the device. Additionally, the
instrument can include a distal portion of the elongate shaft which
is angled relative to a proximal portion of the elongate shaft. As
will be describe below, such an alignment can facilitate proper
positioning of the fixation element within the bone anchors.
[0016] In another aspect, the device for releasably engaging a
spinal fixation element and positioning the instrument can include
a handle having a proximal end and a distal end wherein the distal
end of the handle is coupled to an elongate shaft by an offset.
Further, a distal end of the elongate shaft can include an opening
which is configured to receive a proximal end of a spinal fixation
element. The distal end of the instrument can also being configured
to prevent passage of the manipulation instrument through a
side-wall opening of a percutaneous access device. The instrument
can also include an actuator coupled to the distal shaft of the
instrument wherein the actuator can be in communication with an
engagement element disposed within an inner lumen of the elongate
shaft and being capable of moving the engagement element into and
out of contact with a portion of the spinal fixation element
disposed within the opening of the elongate shaft thereby retaining
or releasing the spinal fixation element from the device upon
actuation.
[0017] These and other aspects of the presently disclosed methods
and devices are described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The various embodiments of the presently disclosed methods
and devices will be more fully understood from the following
detailed description taken in conjunction with the accompanying
drawings, in which:
[0019] FIG. 1A is a representation of a plurality of percutaneous
access devices engaged to a corresponding number of spinal
locations;
[0020] FIG. 1B is a representation of a spinal fixation element
being delivered to a surgical site wherein the element is external
and adjacent to a first percutaneous access device of the plurality
of such devices shown in FIG. 1A;
[0021] FIG. 1C is a representation of the spinal fixation element
of FIG. 1B being laterally passed through the opposed sidewall
openings of several of the percutaneous access devices of FIG.
1A;
[0022] FIG. 1D is a representation of the spinal fixation element
of FIG. 1B being positioned through the opposed sidewall openings
of each percutaneous access devices and seated within spinal
anchors associated with the percutaneous access devices;
[0023] FIG. 2A is a perspective view of an exemplary embodiment of
a percutaneous access device releasably engaged to a spinal
anchor;
[0024] FIG. 2B is a side view of the percutaneous access device of
FIG. 2A;
[0025] FIG. 3A is a perspective view of an exemplary embodiment of
a manipulation instrument;
[0026] FIG. 3B is a side view of the manipulation instrument of
FIG. 3A;
[0027] FIG. 3C is a top view of another embodiment of a
manipulation instrument;
[0028] FIG. 4A is a view of a distal end of the manipulation
instrument of FIG. 3A;
[0029] FIG. 4B is a representation of an orientation between a
proximal portion of a spinal fixation element and the distal end of
the manipulation instrument of FIG. 4A prior to engagement;
[0030] FIG. 5 is an exploded view of the manipulation instrument of
FIG. 3A; and
[0031] FIG. 6 is a view of the distal end of the manipulation
instrument engaged to the spinal fixation element wherein the
distal end of the instrument is configured as a stop element.
DETAILED DESCRIPTION
[0032] Certain exemplary embodiments will now be described to
provide an overall understanding of the principles of the
structure, function, manufacture, and use of the devices and
methods disclosed herein. One or more examples of these embodiments
are illustrated in the accompanying drawings. Those skilled in the
art will understand that the devices and methods specifically
described herein and illustrated in the accompanying drawings are
non-limiting exemplary embodiments and that the scope of the
present disclosure is defined solely by the claims. The features
illustrated or described in connection with one exemplary
embodiment may be combined with the features of other embodiments.
Such modifications and variations are intended to be included
within the scope of the presently disclosed methods and
devices.
[0033] Methods and devices for positioning a spinal fixation
element at a surgical site are provided herein. In general, these
methods and devices facilitate minimally invasive spinal fusion
procedures that can span multiple levels of the spine (e.g., three
levels or more) while minimizing any associated tissue damage. For
instance, the method can include delivering a plurality of
percutaneous access devices to various spinal locations via a
corresponding number of incisions (e.g., four percutaneous access
devices would require four incisions). Next, a spinal fixation
element (e.g., a rigid rod, a polymer rod, a dynamic element, etc.)
can be delivered through tissue via one of the existing incisions
such that, for example, the spinal fixation element can be
positioned adjacent an outer portion of a first percutaneous access
device and delivered through the first incision into the patient.
Once so positioned, the fixation element can be manipulated (e.g.,
via a manipulation instrument) so as to pass laterally through
opposed sidewall openings of the first percutaneous access device
and subsequently through the remainder of the access devices via
similarly positioned opposed sidewall openings of each access
device. Thus, the fixation element passes from the outside of the
first percutaneous access device and transversely through the
remainder of the devices. As will be discussed, such a delivery
trajectory eliminates the need to introduce the fixation element
axially through a proximal opening of the first percutaneous access
device as such delivery and subsequent manipulation typically is
difficult, if not impossible, when utilizing a fixation element
having a length of greater than about 95 mm.
[0034] An exemplary embodiment of a method for delivering a spinal
fixation element to the spine in a minimally invasive surgical
technique is depicted in FIGS. 1A-1D. As shown in FIG. 1A, the
method includes engaging a plurality of spinal implant assemblies
10a, 10b, 10c, 10d, 10e to a plurality of spinal locations 20a,
20b, 20c, 20d, 20e. While a variety of such assemblies can be used
to perform the methods disclosed herein, FIGS. 2A and 2B illustrate
an exemplary embodiment of such an assembly 10 which includes a
percutaneous access device 12 mated to a spinal anchor 50 that is
embedded in a vertebral body. As shown, the percutaneous access
device 12 can be in the form of a generally elongate, cylindrical
tube having a longitudinal axis L that extends between proximal and
distal ends 12a, 12b. The size of the access device 12 can vary
depending on the intended use. In certain exemplary embodiments,
for example, the percutaneous access device 12 may have a length
1.sub.a that allows the proximal end 12a of the access device 12 to
be positioned outside the patient's body, while the distal end 12b
of the access device 12 is coupled to, or positioned adjacent to, a
spinal anchor 50 that is disposed in a vertebra in a patient's
spine. The exemplary percutaneous access device 12 may be implanted
through a minimally invasive percutaneous incision, which is a
relatively small incision that typically has a length that is less
than a diameter or width of the device 10 being inserted
therethrough. For example, a minimally invasive percutaneous
incision may be a stab or point incision through which the
percutaneous access device 12 is positioned. As will be discussed,
various embodiments of the method provided herein limit the number
of incisions to the number of percutaneous access devices 12
required for the procedure.
[0035] The percutaneous access device 12 can further include
opposed sidewall openings 14a, 14b (opening 14b is shown as dashed
lines in FIG. 2A). As will be described, the opposed side wall
openings 14a, 14b allow for a spinal fixation element 30 to pass
laterally through the access device 12 thereby allowing for an
optimized trajectory capable of facilitating the positioning of
relatively longer fixation elements. In general, the width (W) of
the sidewall openings 14a, 14b is generally sized in accordance
with an outer diameter of the spinal fixation element 30. Also, the
sidewall openings 14a, 14b typically begin at a location distal of
the proximal end 12a of the access device 12 and extend to the
distal end 12b of the device 12 thereby allowing the user to seat
the fixation element 30 within the plurality of spinal anchors 50
(discussed below). As will be apparent to those skilled in the art,
the opposed sidewall openings 14a, 14b can have virtually any
shape, width, length, etc. capable of allowing passage therethrough
of the spinal fixation element 30.
[0036] Referring to FIG. 2A, the percutaneous access device 12 can
also be configured to releasably engage a spinal anchor 50. Thus,
the distal end 12b of the percutaneous access device 12 can include
one or more mating elements 18 formed thereon or therein for
engaging the anchor 50. In an exemplary embodiment, the mating
elements 18 are formed on opposed inner surfaces of the distal end
12b of the access device 12. As will be apparent to those skilled
in the art, a wide range of such mating element can be utilized
with the presently disclosed devices and methods. For example, the
mating elements can include threads, a twist-lock engagement, a
snap-on engagement, a dovetail coupling, or any other technique
known in the art. In an exemplary embodiment, a percutaneous access
device can be coupled to a corresponding bone anchor via a
break-off coupling as disclosed in assignee's co-pending U.S.
patent application Ser. No. 11/561,455, entitled "Break-off Screw
Extensions," filed on Nov. 20, 2006, the entirety of which is
incorporated herein by reference. Exemplary techniques for mating
the percutaneous access device 12 to an anchor 50 are disclosed in
commonly owned U.S. Pat. No. 7,179,261, entitled "Percutaneous
Access Devices and Bone Anchor Assemblies," which is incorporated
by reference in its entirety herewith. Those skilled in the art
will appreciate that a variety of other techniques can be used to
removably mate the percutaneous access device 12 to an anchor
50.
[0037] A variety of spinal anchors 50 can be used with the
presently disclosed percutaneous access device(s) 12, including,
for example, spinal screws, hooks, bolts, and wires. FIG. 2A
illustrates a spinal screw that includes a distal, bone-engaging
portion, e.g., a threaded shank 54, and a proximal, U-shaped
receiver member head 52 that is adapted to seat a spinal fixation
element 30, for example a fixation rod. The threaded shank 54 can
be fixedly attached to the receiver head 52 to form a monoaxial
screw, or alternatively the shank 54 can be configured as a
polyaxial screw, as shown, that is rotatably disposed through an
opening formed in the distal end of the receiver head 52 to allow
rotation of the shank 54 with respect to the receiver head 52. A
variety of techniques can be used to allow rotation of the head 52
with respect to the shank 54.
[0038] As indicated above, the method can include delivering any
number of spinal implant assemblies 10a, 10b, 10c, etc. to a
corresponding number of spinal locations 20a, 20b, 20c, etc. (e.g.,
vertebrae) as required by a given procedure. For example, the
method can include delivering two assemblies 10a, 10b, three
assemblies 10a, 10b, 10c, four assemblies 10a, 10b, 10c, 10d, etc.
In the exemplary embodiment of FIG. 1A, the method includes
engaging five assemblies 10a, 10b, 10c, 10d, 10e (i.e., spinal
anchor 50 and associated percutaneous access device 12) to five
respective spinal locations 20a, 20b, 20c, 20d, 20e thereby
allowing for a four-level spinal fusion.
[0039] Following placement of the various assemblies 10a, 10b, 10c,
etc., a spinal fixation element 30 can be delivered to the surgical
site along an optimized trajectory and manipulated so as to seat
the element 30 within the plurality of spinal anchors 50. The
spinal fixation element 50 can be delivered through the same
incision that accommodates one of the access devices 12, such as
the most cephalad or caudal access device. FIGS. 1B-1D illustrate
delivery of the spinal fixation element 30 from its point of
insertion along a trajectory which facilitates positioning of a
large-scale (e.g., greater than about 95 mm in length) spinal
fixation element 30. More specifically, FIG. 1B shows the plurality
of percutaneous access devices 12 engaged to a plurality of spinal
locations 20a, 20b, etc. wherein each access device 12 is delivered
via an individual incision and associated pathway. Once these
devices 12 are so positioned, a distal portion 30a of the spinal
fixation element 30 can be positioned adjacent an outer portion of
a first percutaneous access device 12 and subsequently inserted
through the corresponding first incision and delivered to a
position adjacent to the distal end 12b of the percutaneous access
device 12 as shown in FIG. 1B. Thus, the spinal fixation element 30
is delivered through the tissue via the same incision created for
the delivery of the first percutaneous access device 12 thereby
eliminating the need to create additional incision(s) to
accommodate the fixation element. The spinal fixation element 30
can be delivered at any angle capable of facilitating delivery and
placement of the element 30 relative to the plurality of access
device(s) 12. For example, the spinal fixation element 30 can be
delivered substantially parallel to a longitudinal axis (L) of the
percutaneous access device 12. In other embodiments, the spinal
fixation element 30 can be delivered at an angle of about
45.degree. or less relative to the longitudinal axis (L) of the
percutaneous access device 12.
[0040] Referring to FIG. 1C, the fixation element 30 can be further
be manipulated so as to insert the distal end 30a of the element 30
laterally through the opposed sidewall openings 14a, 14b of the
first percutaneous access device 30. Once the fixation element 30
has passed through the sidewall openings 14a, 14b of the first
percutaneous access device 12, the element 30 is further advanced
through the opposed sidewall openings of all additional
percutaneous access devices 12 of the remaining assemblies 10b,
10c, 10d, 10e. Finally, as shown in FIG. 1D, the spinal fixation
element 30 is positioned through the opposed sidewall openings 14a,
14b of each percutaneous access device 12 and placed within the
plurality of spinal anchors 50 disposed within the various spinal
locations 20a, 20b, 20c, 20d, 20e such that at least a portion of
the spinal fixation element resides within each of the plurality of
spinal anchors 50. Following this placing step, the spinal fixation
element 30 can then be detached from a manipulation instrument 40
(discussed below) and the instrument 40 can be withdrawn from the
treatment site. The ability to securely engage the fixation element
30 during placement and positioning of the element 30 within the
plurality of bone anchors 50 in contrast to releasing the fixation
element 30 and attempting to manually (or by means of additional
devices) position the element 30 can significantly improve the
efficiency and effectiveness of the stabilization procedure. The
method can further include a mechanism for securing the spinal
fixation element 30 to the plurality of spinal anchors 50, for
example, by threading a plurality of set screws (not shown) into
the plurality of spinal anchors 50.
[0041] In light of the above-described delivery trajectory, the
percutaneous access devices 12 can include closed proximal ends 12a
thereby providing various advantages. For example, closed end
devices are easier to manipulate and/or engage additional
instrumentation thereto as compared to open-ended devices. Further,
the use of such closed proximal end devices 12a allows for a single
percutaneous access device 12 to be employed as compared to common
procedures requiring both closed and open ended devices wherein the
use of a single type of access device 12 facilitates the user's
ability to determine the depth of the access device 12 relative to
the tissue and also facilitates the user's ability to determine if
any of the devices are misaligned. For at least these reasons, the
use of percutaneous access devices 12 having closed proximal ends
12a provides significant advantages over commonly known techniques
and devices.
[0042] As indicated above, the spinal fixation element 30 can
include virtually any element capable of providing the desired
spinal fixation. For example, the spinal fixation element 30 can be
a rigid rod (e.g., a titanium rod), a polymer rod, and/or a dynamic
element. In some embodiments, the fixation element can include a
variable diameter along a length of the element. Additionally, the
length and/or dimensions of the fixation element can be selected
and/or configured as required by a given procedure. For example, in
an exemplary embodiment, the spinal fixation element 30 can have a
length greater than about 95 mm. In other embodiments, the spinal
fixation element 30 can have a length greater than about 100 mm,
greater than about 105 mm, greater than about 110 mm, greater than
about 120 mm, etc. It will be apparent to those skilled in the art
that a spinal fixation element 30 can have any length as required
by a given procedure. For example, the fixation element can have a
length suitable for a 2-level procedure (i.e., a single construct),
3-level procedure, a 4-level procedure, a 5-level procedure, or
greater level procedure. Additionally, the spinal fixation element
can be straight, pre-contoured to match the desired curvature of
the spine in the appropriate region, or bendable by a surgeon to
achieve a desired contour.
[0043] In addition to the methods provided above, various
embodiments of a manipulation instrument 40 configured to
facilitate positioning and/or manipulation of the element 30 are
also provided herein. As described below, the manipulation
instrument 40 can be configured in various manners to facilitate
delivery of a large-scale fixation element 30 as well as proper
positioning of the element within the various spinal anchors. Such
a manipulation instrument, as well as other components described
herein, can be provided as part of a kit or system. FIGS. 3A-3C
provide various views of an exemplary embodiment of a manipulation
instrument 40 capable of releasably engaging and delivering a
spinal fixation element 30 to a desired surgical site. As shown,
the instrument 40 can include a shaft 44 having a proximal end
coupled to a handle 42 and a distal end coupled to a clamping
mechanism 46. In order to facilitate manipulation of large-scale
fixation elements 30, the shaft 44 of the instrument 40 can be
offset relative to the handle 42 such that the handle 42 is not
collinear with the clamping mechanism 46 thereby positioning the
handle 42 away from the patient which enhances maneuverability
and/or visibility as the user manipulates the spinal fixation
element 30 into a desired position (see FIG. 1C). Such an offset
configuration can be achieved in various ways. For example, as
shown in FIG. 3A the shaft 44 can include a first length L.sub.1, a
second length L.sub.2 and a third length L.sub.3 wherein the second
length L.sub.2 is oriented at an angle .theta..sub.a relative to
the first length L.sub.1. Also, as will be further described below,
the above-described configuration of the instrument 40 (e.g., the
offset and various curves) can allow for easier access to an
actuator 64b configured to release a spinal fixation element
engaged to the instrument 40. Additionally, the distal portion of
the clamping mechanism 46 can be configured to be at an angle
.theta..sub.b relative to the proximal end of the clamping
mechanism 46 thereby ensuring proper positioning of the fixation
element 30 within the spinal anchors. More specifically, angling
the clamping mechanism 46 as such ensures that the fixation element
is completely positioned within the first bone anchor as opposed to
over-insertion of the element 30 which could prevent a closure
mechanism from properly securing the fixation element 30 within the
first bone anchor.
[0044] The handle 42 of the instrument 40 can also be configured to
provide enhanced maneuverability and/or control over the fixation
element during delivery to the surgical site. For example, the
handle 42 can be oversized (e.g., large diameter and/or length) so
as to provide leverage to a user relative to the fixation element.
Such added leverage and enhanced control can be of increased
importance for those procedures requiring the use of large fixation
elements. Additionally, as illustrated in FIG. 3C, the handle 42
can be angled relative to the shaft thereby facilitating delivery
of the fixation element. As will be appreciated by those skilled in
the art, the handle can be configured in various other manners so
as to improve the user's ability to accurately deliver and/or
position the fixation element.
[0045] As indicated above, the instrument 40 can include a clamping
mechanism 46 having a distal portion 48 configured to releasably
engage the spinal fixation element 30. For example, as shown in
FIGS. 4A and 4B, the distal portion 48 of the clamping mechanism 46
can include an opening 48o configured to receive the proximal end
30a of the spinal fixation element 30. When the proximal end 30a of
the fixation element 30 is positioned within the opening 48o, the
element 30 can be secured therein by various mechanisms. For
example, as will be explained in greater detail in relation to FIG.
5, the clamping mechanism 46 can be in communication with an
actuator 64b configured to allow a user to selectively engage or
disengage the fixation element 30. FIG. 5 provides an exploded view
of the manipulation instrument 40 to illustrate the inner workings
of the clamping mechanism 46. As shown, the instrument 40 is
comprised of various components such as the clamping mechanism 46,
the shaft 44, and the handle 42. In such an embodiment, the various
components can be coupled to one another via any well known method
(e.g., use of a ball plunger 66). In other embodiments, any or all
of these components 42, 44, 46 can be permanently mated to one
another or can be formed as a single component. Referring to the
clamping mechanism 46, a distal portion 47 (see FIG. 3B) of the
mechanism 46 can be angled (.theta..sub.b) so as to ensure proper
positioning of the fixation element 30 within the bone anchors.
Additionally, the clamping mechanism 46 can include a central bore
(not shown) extending therethrough and in communication with the
distal opening 48o thereby allowing an engagement element 60 and a
driver 64 to slide along the central bore so as to engage and/or
disengage the fixation element 30. As will be described, these
elements 60, 64 can be configured to slide along the central bore
in response to a force supplied to the actuator 64b. In this
example, the elements 60, 64 will be shown as distinct elements.
However, as will be clear to those skilled in the art, these
components could be a single element or more than two elements.
[0046] Thus, in the exemplary embodiment shown in FIG. 5, the
engagement element 60 can include a distal end 60a configured to
securely engage the proximal portion 30b of the fixation element
30. As illustrated in FIG. 4B, in a biased state, the distal
portion 60a of the engagement element 60 resides in a retracted
position within the clamping mechanism 46. Upon actuation
(described below), the distal portion 60a is advanced distally so
as to engage a corresponding groove 31 (FIG. 4B) of the fixation
element 30. The engagement element 60 further includes a proximal
end 60b configured to have a larger diameter as compared to the
remainder of the element 60 thereby allowing a resilient element
(e.g., a spring) 62 to be positioned over the element 60 and sized
to abut the enlarged distal portion 60b. When assembled, a distal
portion of the spring 62 can engage the surrounding walls of the
inner bore thereby resulting in the above-described biased,
retracted position. As will be shown below, in use, the user can
supply a force to the actuator 64b which results in the spring 62
being compressed and the distal end 60a of the engagement element
60 being brought into contact with the portion of fixation element
30 disposed within the distal opening 48o. Additionally, a slot 68
can be incorporated within the engagement component 60 such that
the slot 68 is configured to receive a set-pin 70 disposed through
a hole 72 in the distal portion of the clamping mechanism 46. Thus,
the set-pin 70 and the associated slot 68 can be configured to
limit movement of the engagement element 60 between the biased,
retracted position and the extended position.
[0047] As mentioned, in this exemplary embodiment, a driver 64 can
be in communication with the engagement element 60 such that the
driver 64 can translate a force from the actuator 64b to the
engagement element 60. Thus, as shown, the driver 64 can include a
distal end 64a configured to abut the proximal end 60b of the
engagement element 60, and the driver 64 can further include the
actuator 64b at the proximal end and accessible to a user. A
proximal portion of the driver 64 (distal of the actuator 64b) can
include a threaded portion 63 configured to engage a corresponding
threaded portion (not shown) incorporated into the clamping
mechanism 46. Thus, by rotating the actuator 64b in a first
direction (e.g., clockwise), the driver 64 can advance in a distal
direction via the threaded portions. As the driver 64 advances, a
force is supplied to the engagement element 60 thereby overcoming
the biasing force of the spring 62 and forcing the distal end 60a
of the engagement element 60 against the proximal end 30b of the
spinal fixation element 30. Upon rotating the actuator 64b in an
opposite direction (e.g., counter clockwise), the force is removed
and the engagement element 60 is free to return to the biased,
retracted position. Referring once again to FIG. 5, the clamping
mechanism 46 can also include a removable portion 74 thereby
allowing for maintenance, cleaning, and/or repair/replacement of
any of the various internal components. In other embodiments, the
portion 74 is welded in position.
[0048] In another embodiment, the manipulator instrument 40 can be
configured to facilitate proper positioning of the spinal fixation
element 30 relative to the plurality of percutaneous access devices
12 and corresponding spinal anchors 50. For example, as illustrated
in FIG. 6, a distal end 48 of the clamping mechanism 46 can be
configured to prevent passage of the distal portion 48 within
and/or through the sidewall opening of the first percutaneous
access device 12 thereby indicating to the user when the spinal
fixation element 30 has been delivered through each of the
assemblies 10a, 10b, etc. utilized by the given procedure. The
distal end 48 of the extension can include various configurations
capable of achieving the desired result. In an exemplary
embodiment, the distal portion 48 of the clamping mechanism 46 can
be substantially planar and has a diameter larger than of the
spinal fixation element 30. Those skilled in the art will
appreciate that the distal end 48 can include virtually any such
configuration capable of preventing passage of the distal end 48 of
the clamping mechanism 46 within and/or through the opposed
sidewall openings.
[0049] One skilled in the art will appreciate further features and
advantages of the presently disclosed methods and/or devices based
on the above-described embodiments. Accordingly, the disclosure is
not to be limited by what has been particularly shown and
described, except as indicated by the appended claims. All
publications and references cited herein are expressly incorporated
herein by reference in their entirety.
* * * * *