U.S. patent application number 15/136615 was filed with the patent office on 2016-10-27 for system for sacroiliac joint fusion.
This patent application is currently assigned to Camber Spine Technologies, LLC. The applicant listed for this patent is Camber Spine Technologies, LLC. Invention is credited to Kenan Aksu, MICHAEL BLACK, Damian Heinz.
Application Number | 20160310197 15/136615 |
Document ID | / |
Family ID | 57146614 |
Filed Date | 2016-10-27 |
United States Patent
Application |
20160310197 |
Kind Code |
A1 |
BLACK; MICHAEL ; et
al. |
October 27, 2016 |
SYSTEM FOR SACROILIAC JOINT FUSION
Abstract
A system for preparing the sacroiliac (SI) joint for an SI joint
fusion, and optionally delivering an implant to the SI joint, is
described herein. The implant is inserted via an inferior inlet
approach. A sliding joint finder is inserted into the joint,
followed by insertion of a working cannula. The working cannula is
operatively coupled to the sliding joint finder, in that it is
configured to fit over the sliding joint finder, allowing
subsequent removal of the sliding joint finder, and providing a
hollow cavity for joint fusion preparation, decortication and
insertion of an implant. This system and method provides a less
invasive and safer approach for fixing an SI joint or delivering an
implant to the SI joint than currently available methods.
Inventors: |
BLACK; MICHAEL;
(Phoenixville, PA) ; Aksu; Kenan; (Exton, PA)
; Heinz; Damian; (Wayne, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Camber Spine Technologies, LLC |
Wayne |
PA |
US |
|
|
Assignee: |
Camber Spine Technologies,
LLC
|
Family ID: |
57146614 |
Appl. No.: |
15/136615 |
Filed: |
April 22, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62151842 |
Apr 23, 2015 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/1659 20130101;
A61F 2002/30995 20130101; A61F 2002/3093 20130101; A61B 17/1604
20130101; A61B 17/17 20130101; A61B 2017/922 20130101; A61B 17/1671
20130101; A61B 17/92 20130101; A61B 17/1757 20130101 |
International
Class: |
A61B 17/92 20060101
A61B017/92; A61F 2/30 20060101 A61F002/30 |
Claims
1. A surgical system for preparing the sacroiliac (SI) joint for a
fusion, comprising a sliding joint finder and a working cannula a)
wherein the sliding joint finder comprises i) a central axis with a
hole that runs the length of the sliding joint finder; ii) a
unilateral shelf located on the outer surface of the sliding joint
finder; and b) wherein the working cannula comprises a body having
a central axis that runs the length of the body, wherein the body
comprises a distal end, a proximal end and a cavity that is
positioned along the central axis and has suitable dimensions for
sliding the working cannula over the sliding joint finder.
2. The surgical system of claim 1, further comprising an implant
insertion tool, wherein the implant insertion tool comprises an
elongated body and a slidable insertion ram, wherein the body of
the insertion tool comprises an insertion region and an insertion
end, and a central cavity that runs along a central axis, wherein
the slidable insertion ram comprises a body portion located in the
central cavity and in slidable relation thereto, and wherein the
insertion region and insertion end have suitable dimensions for
insertion of a spacer into the working cannula.
3. The system of claim 1, wherein the hole that runs the length of
the sliding joint finder has suitable dimensions to slide over and
allow for removal of wire or pin.
4. The system of claim 1, wherein the sliding joint finder has two
lateral sides, and wherein the unilateral shelf of the sliding
joint finder is located on only one of the lateral sides at a
suitable location for contacting a shelf on the ilium, when it is
inserted into the SI joint with the lateral side facing the
ilium.
5. The system of claim 1, wherein the working cannula further
comprises a unilateral shelf at its proximal end.
6. The system of claim 5, wherein the longer of the two protrusions
of the working cannula is configured to fit into the superior end
of the SI Joint and the shorter of the two protrusions is
configured to fit into the inferior end of the SI joint.
7. The system of claim 1, wherein the insertion end of the body of
the insertion tool comprises a flexible tab that can be deformed to
retain one or more implants within the insertion end.
8. The system of claim 7, wherein the slidable insertion ram of the
implant insertion tool is configured to push the implant(s) out of
the insertion end and into the joint, when the insertion ram moves
from a retracted position to an operative position.
9. The system of claim 7, wherein the insertion end of the implant
insertion tool comprises a cavity configured to retain an implant,
when the tab is deformed.
10. The system of claim 6, further comprising one or more
spacers.
11. The system of claim 10, wherein the one or more spacers is
formed from a material selected from the group consisting of
allograft, autograft bone, biocompatible metal, polymers, ceramics,
and other synthetic materials.
12. The system of claim 1, wherein the cavity of the working
cannula has a substantially straight lateral walls.
13. The system of claim 1, further comprising one or more tools for
preparing the SI Joint selected from the group consisting of drill
guides and joint box chisels, wherein each of the tools has a
proximal end, and wherein each of the tools has suitable dimensions
for the proximal end of the tool to be inserted into the working
cannula.
14. The system of claim 1, wherein the distal end of the working
cannula is configured to receive a lateral guide for fixation
elements.
15. A method of guiding an implant into the SI joint using the
system of claim 1, comprising: a) accessing the joint with a wire
or pin; b) orienting the sliding joint finder over the wire or pin
and sliding it into the joint until the unilateral shelf contacts
the shelf of the ilium; c) inserting the working cannula over the
sliding joint finder until the distal end of the working cannula
reaches the distal end of the sliding joint finder; and d) removing
the sliding joint finder and wire or pin, wherein the working
cannula remains in the SI joint.
16. The method of claim 15, wherein the method further comprises
after step (d), e) inserting into the cavity of the working
cannula, an implant insertion tool comprising one or more implants
in its insertion end, wherein the implant insertion tool comprises
an elongated body and a slidable insertion ram, wherein the body of
the insertion tool comprises an insertion region and an insertion
end, and a central cavity that runs along a central axis, and
wherein the slidable insertion ram comprises a body portion located
in the central cavity and in slidable relation thereto.
17. The method of claim 16, further comprising pushing the slidable
insertion ram from a retracted position to an operative position,
wherein the slidable insertion ram comprises a proximal end that
contacts a posterior surface of the implant, and wherein the
implant pushes the tab and the proximal end of the ram pushes the
implant into the prepared SI joint.
18. The method of claim 15, wherein the approach is an inferior
inlet approach.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to U.S. Provisional
Application No. 62/151,842, filed on Apr. 23, 2015, by Michael
Black, Kenan Aksu, and Damian Heinz, the disclosure of which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to surgical
procedures for a sacroiliac (SI) joint, and more specifically, to
systems for guiding and delivering SI joint implants in place.
BACKGROUND OF THE INVENTION
[0003] Sacroiliac (SI) joints are located between the sacrum and
the right and the left iliac bones, respectively. The sacrum is a
triangular bone in the lower back formed from fused vertebrae and
situated between the two hipbones of the pelvis. The ilium is the
largest and uppermost bone of the pelvis.
[0004] The SI joints provide support for the entire weight of the
upper body when a human stands erect, which creates a large amount
of stress on the SI joints. Therefore, these joints are susceptible
to injury and degeneration. Acute and chronic injury, degeneration,
and laxity of the supporting ligaments of the SI joint can result
in low back and radiating buttock and leg pain in afflicted
patients. Stabilization or immobilization (fixation) of the SI
joint is commonly advocated as a surgical treatment for many SI
joint disorders.
[0005] A significant problem with certain conventional methods for
SI joint fixation is that they require a surgeon to have direct
access and a view of the SI joint. Thus, some conventional SI joint
fixation techniques require the use of what is commonly referred to
as "open surgery," and result in significant trauma and disruption
to the tissues and skin surrounding the SI joint. Open procedures
increase the risk of damage to major nerves, blood vessels,
ligaments, and muscles around the incision site. Moreover, open
procedures increase operative, hospitalization, and recovery time
due to the extensive soft tissue damage resulting from open surgery
techniques.
[0006] In response to the problems related to open surgery for SI
joint fixation, minimally invasive surgical (MIS) procedures were
developed. Currently, one of two approaches is taken to access the
SI joint for fixation procedures: a lateral approach and a
posterior approach. In conventional MIS procedures employing the
lateral approach, screws, rods, or other fixation devices are
passed through a small incision (as compared to that in open
surgery) made on the lateral hip and inserted laterally through the
ilium, across the SI joint space, and into the sacrum. See, e.g.
U.S. Pat. No. 8,221,428 by Trieu.
[0007] Alternatively, a posterior approach may be used to access
the SI joint for delivery of SI joint implants. See, e.g. U.S.
Publication No. 2012/0316565 by Stark and U.S. Publication No.
2013/0035723 by Donner. In the posterior approach disclosed by
Stark and Donner a small (as compared to that in open surgery)
incision made in the patient's back, and the SI joint is accessed
through an extra-articular recess located between the sacrum and
the ilium.
[0008] Although the points of incision are different in current MIS
procedures for accessing the SI joint, neither is truly minimally
invasive. Conventional lateral MIS procedures still may result in
significant trauma to the major nerves, blood vessels, and muscle
groups of the hip. While current posterior MIS approaches eliminate
damage to the soft tissues and neurovascular system of the lateral
hip, they still carry a significant risk of trauma to the spinal
nerves and major back and hip ligaments.
[0009] There exists a need for improved MIS systems and procedures
that are less invasive and decrease soft tissue trauma and the risk
to neurovascular tissue during SI joint fixation procedures.
[0010] Therefore, it is an object of the invention to provide an
improved, less invasive system and method for stabilizing an SI
joint.
SUMMARY OF THE INVENTION
[0011] A system and method for preparing the sacroiliac (SI) joint
and delivering an implant to the SI joint is described herein. In
the methods, the SI joint is accessed using a sliding joint finder
and a working cannula, which are inserted into the space via an
inferior inlet approach. In some embodiments, the method includes
inserting an implant into the joint space. In these embodiments,
the system includes an implant insertion tool. The system and
method provide a less invasive and safer approach for repairing
and/or stabilizing an SI joint than currently available
methods.
[0012] Preferably, a sliding joint finder is inserted into the
joint, followed by insertion of a working cannula. The working
cannula is configured to fit over the sliding joint finder,
allowing subsequent removal of the sliding joint finder, and
provides a hollow cavity for joint fusion preparation,
decortication and insertion of an implant. Optionally, various
excavation tools, drill guides and implant insertion tools are
configured for insertion into the working cannula. After the SI
joint space is prepared, an implant may be inserted into the
prepared SI joint.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows an exemplary sliding joint finder (100)
including two large frontal radii (110a and 110b) and a unilateral
shelf (120). The side displayed is labeled (130) to indicate that
it should be inserted facing the ilium. The distal end (140) has an
expanded surface area.
[0014] FIG. 2 is a cross-sectional perspective view of the distal
half of an exemplary sliding joint finder (100). The side displayed
is labeled (130) to indicate that it should be inserted facing the
ilium. The distal end (140) has an expanded surface area. Also
shown is a hole (150) running down the central axis, allowing the
sliding joint finder to slide over a pin or wire, such as Kirschner
wire (K-Wire), and for the pin or wire to be removed.
[0015] FIG. 3A is a side view of an exemplary working cannula (200)
with a lateral slot (280) located in the handle portion (220) near
the distal end (210) of the working cannula. As shown in FIG. 3A,
optionally a lateral guide boom (300) can be inserted into the
lateral slot (280). The proximal end (240) of the working cannula
has two protrusions (242a and 242b) containing sharp edges (250a
and 250b). One protrusion is located on the superior side of the
cannula and the other is located on the inferior side of the
cannula. The side (228) of the working cannula shown in FIG. 3A is
marked (226a) to indicate that it should face the ilium. This side
of the working cannula contains a unilateral shelf (260), which is
located proximal to the two protrusions and, optionally, contains
one or more holes or slots (224, 232a, 232b). The lateral guide
boom has a curved L shape, the proximal end of which ends in a
substantially rectangular paddle-like structure (320) with one,
two, or more holes (310a, 310b, 310c). FIG. 3B shows a lateral
guide clamp (1200), which fits into the distal end of the working
cannula.
[0016] FIG. 4 is a partial cross-sectional perspective view of an
exemplary working cannula (200). The side shown is labeled (226b)
to face the sacrum. Also shown is a long rectangular slot (292)
running down its length.
[0017] FIGS. 5A-5C show a side view (FIG. 5A) and two cross
sectional views (FIGS. 5B and 5C) of an exemplary implant insertion
tool (500). FIG. 5B shows the insertion end without an implant.
FIG. 5C shows the insertion end with an implant enclosed therein.
The insertion end (510) captures and encapsulates the implant
(600). The insertion end (510) contains a rectangular cavity (512),
into which the implant fits, and a tab (515). A slidable insert ram
(560), which is in slidable relation to the central cavity of the
body, is configured to push the implant out of the insertion
end.
[0018] FIGS. 6A-6D show exemplary allograft implants of various
sizes (600a, 600b, 600c, 600d). The implant may have one or a
plurality of holes (610, 620) of various sizes along its length,
allowing for insertion of bone graft. The corners of the implant
are rounded (630) and the upper and lower sides of the implant have
triangular projections (640).
[0019] FIG. 7 shows a side view of an exemplary joint box chisel
(900), with a sharp rectangular cutting edge (912), a long,
box-shaped cavity (920), lateral markings (930) facilitating
control of cutting depth, and a cylindrical head (940).
[0020] FIG. 8 is a side view of an exemplary joint rasp (1000),
with a proximal end having a rounded leading edge (1010), two flat
sides (1026, 1024), each of which has a pattern of sharp diamond
shaped structures (1022), lateral markings (1030) facilitating
control of cutting depth, and a cylindrical head (1040).
[0021] FIG. 9 shows a view of an exemplary drill guide (1100).
[0022] FIG. 10 shows a view of an exemplary working cannula (200)
inserted into the SI joint.
DETAILED DESCRIPTION OF THE INVENTION
I. Definitions
[0023] As used herein, the term "align" refers to the arrangement
of two or three, or more objects so that they form a substantially
straight line.
[0024] As used herein, the term "allograft" refers to a transplant
of tissue, typically with reference to bone, from one individual to
another of the same species.
[0025] As used herein, the term "cavity" refers to an empty space
within a solid object, such as an empty space in a tool, or in the
human body.
[0026] As used herein, the term "decortication" refers to the
removal of tissue in preparation for placement of an implant.
[0027] As used herein, the term "distal" refers to being situated
away from the center of the body or from the point of
attachment.
[0028] As used herein, the term "lateral" refers to of, at, toward,
or from the side or sides.
[0029] As used herein, the term "protrusion" refers to an object
that sticks out from another, such as a bump, lump, knob, ledge, or
other projection.
[0030] As used herein, the term "proximal" refers to being situated
nearer to the center of the body or the point of attachment.
[0031] As used herein, the term "shelf" refers to a protruding
ledge.
[0032] As used herein, the term "slot" refers to a long, narrow
aperture or slit.
[0033] As used herein, the term "superior" refers to the upper
surface of a structure (as opposed to the lower surface).
[0034] As used herein, the term "unilateral" refers to being
situated or positioned on one side of an object.
II. System
[0035] A system for guiding a joint implant system into place in a
minimally invasive manner, related components, and exemplary
methods of employing the implant system are described herein. In a
preferred embodiment, the system is employed to guide a sacroiliac
(SI) joint implant into place.
[0036] The system includes a sliding joint finder and a working
cannula. In some embodiments, the system also includes an implant
insertion tool. Optionally, additional components, such as specific
implants, implant insertion tools, joint box chisels, joint rasps,
and K-Wires are used in or with the system. The various components
of the SI implant system are fabricated from biocompatible
materials suitable for insertion in a human body, including but not
limited to, metals, synthetic polymers, ceramics, and/or their
combinations, depending on the particular application and/or
preference of a medical practitioner. Further, the components of
the implant system can be manufactured via various methods, such as
by injection-molding, insert-molding, co-extrusion, pultrusion,
transfer molding, overmolding, compression molding, 3-Dimensional
printing, dip-coating, spray-coating, powder-coating,
porous-coating, milling from a solid stock material and their
combinations.
[0037] A. Sliding Joint Finder
[0038] The sliding joint finder has a hollow central region that
runs down the central axis of its body. The width of the proximal
end of the sliding joint finder is configured for it to fit
directly into the SI joint. Optionally, the proximal end of the
sliding joint finder also contains large frontal radii to deflect
and dilate tissue encountered during insertion. The body of the
sliding joint finder has two distinct sides, one side is configured
for placement adjacent to the sacrum and the opposite side is
configured for placement adjacent to the ilium. Preferably each
side is labeled to distinguish one side from the other. Typically,
the side that is configured to be placed adjacent to the ilium
contains a shelf located adjacent to the proximal end at a suitable
length to contact the ilium and prevent over insertion of the
sliding joint finder. The shelf is adjacent to first end of each of
the protrusions.
[0039] Referring to FIGS. 1 and 2, the sliding joint finder (100)
is generally rectangular in its cross sectional shape, with the
height being about twice that of the width. While the Figures
illustrate a generally rectangular-shaped sliding joint finder, the
sliding joint finder can have any other shape that allows it to fit
inside the working cannula. It has a hole (150) that runs down the
central axis to allowing the sliding joint finder to slide over a
pin or wire, such as a Kirschner Wire (K-Wire), and for the pin or
wire to be removed through the sliding joint finder from the
patient's body. The width of the leading end (110) of the sliding
joint finder allows it to fit directly into the SI joint. In
certain embodiments the leading edge (110) has large frontal radii
(112a, 112b) that are approximately equal to the height of the
sliding joint finder, to deflect and dilate tissue encountered
during insertion.
[0040] Preferably, the sliding joint finder has two distinct sides
(one side, 130, is shown in FIG. 1, the other side is opposite it),
one configured to face the sacrum and the other configured to face
the ilium, preferably each side is labeled (132) to distinguish it
from the other side. In some embodiments a shelf (120) is located
on one of these sides to control the depth of insertion into the
joint.
[0041] The unilateral shelf (120) is located at a suitable distance
along one side (130) of the sliding joint finder to control the
depth of insertion into the joint, by contacting the edge of the
posterior inferior iliac spine. The unilateral shelf also
establishes two distinct sides of the sliding joint finder, so that
when inserted into the joint, one side of the sliding joint finder
faces the sacrum, while the other side faces the ilium. The side
that contains the unilateral shelf corresponds with the side that
should be adjacent to the ilium when the sliding joint finder is
inserted into the joint. The sliding joint finder is optionally
labeled on at least one side, optionally on both sides, to help a
user distinguish the two sides, for example, one side can be
labeled "S" for "sacrum", the other "I" (132) for "ilium".
[0042] The sliding joint finder also has a long rail (160) running
down its length, which can serve as a guide for other tools, such
as the working cannula to ensure that they are placed at the
desired site and in the desired orientation in the patient's
body.
[0043] In some embodiments the sliding joint finder has holes or
slots on its sides which serve to reduce the weight of the
instrument and facilitate cleaning. In some embodiments the distal
end (140) of the sliding joint finder has an expanded surface area,
providing a larger surface for impaction, if needed, such as by
hitting the distal end with a mallet.
[0044] B. Working Cannula
[0045] The working cannula is an instrument that has a suitable
height and width for insertion into the SI Joint and to interact
with the other tools in the system. The working cannula contains a
cavity, which runs down the central axis. The cavity provides a
working space through which other tools in the system are inserted
and within which the other tools are used to prepare the SI Joint,
or insert the implant into the SI Joint. Typically, the height of
the working cannula is about twice that of its width. Preferably
the lateral walls of the cavity are substantially straight. The top
and bottom portions of the cavity may be straight or curved. As
shown in FIGS. 3A, 3B and 4, the working cannula may have a
rectangular shaped cavity. This is particularly useful for
inserting implants that are generally rectangular in shape.
However, the cavity of the working cannula can have any suitable
shape and size that allows the tools to fit inside of it, and
optionally, an implant, such as a spacer, to be inserted through
it. As shown in the Figures, the tools that are used with the
working cannula have a suitable shape and size to fit in the
working cannula. The tools described herein can be modified to have
any suitable shape that fits in the correspondingly shaped cavity
of the working cannula.
[0046] The proximal end of the working cannula contains two
protrusions, which terminate in sharp edges. When the working
cannula is inserted into the SI Joint, the sharp edges of the
protrusions of the working cannula hold the joint open and retain
the working cannula in position.
[0047] An exemplary working cannula is illustrated in FIGS. 3A and
4. Referring to FIG. 3A, the working cannula (200) has a generally
rectangular shaped body having a central axis that runs the length
of the body. The cannula body has a distal end (210), a proximal
end (240) and a substantially rectangular cavity (290) that is runs
along the central axis. The cannula also contains a handle portion
(220) and an insertion portion (230). Optionally, the distal end
(210) of the handle portion is configured to receive a lateral
guide clamp (1200) as illustrated in FIGS. 3A and 3B. The lateral
guide clamp contains a slot (1204) which is sized to receive
instrument for guiding fixation elements, such as a lateral guide
boom (300), via lateral insertion into the slot. A fastening device
such as a nut can be screwed onto the distal end (1202) of the
lateral guide clamp to secure the lateral guide boom to the handle
portion of the working cannula.
[0048] The proximal end (240) of the working cannula terminates at
the second ends (244a, 244b) of the two protrusions (242a and
242b), where the protrusions have different lengths. The distance
between the two protrusions is selected so that the protrusions fit
directly into the SI joint (FIG. 10). The distance between the
protrusions is selected to allow insertion of an implant, such as a
spacer, directly between them. In a preferred embodiment, the
protrusions allow insertion of an implant that has a height of 15
mm. The second ends (244a, 244b) of the protrusions typically have
sharp, pointy edges that deflect and dilate any tissues they
encounter during insertion.
[0049] When the working cannula is correctly oriented within a
patient, the longer protrusion 242a is located at the superior side
and shorter protrusion 242b at the inferior side of the SI joint,
thus preventing insertion of the cannula through the joint (see
FIG. 10). In a preferred embodiment, the working cannula has a
shelf (260) on one side, which controls the depth of insertion into
the joint. In these embodiments, the proximal end (240) of the
working cannula begins at the location of the shelf (260) and
terminates at the second ends (244a, 244b) of the protrusions (242a
and 242b). Typically the shelf (260) is on the side (228) of the
working cannula that should be located adjacent to the ilium, and
is positioned adjacent to the first end (243a, 243b) of each of the
protrusions. The distance from the longest protrusion (240a) to the
shelf is typically about 35 mm. The distance from the shortest
protrusion (240b) to the shelf is typically about 15 mm.
[0050] Referring to both FIGS. 3A and 4, the working cannula has
two distinct sides, a first side (228) configured to face the ilium
and the second, opposite side (229), configured to face the sacrum.
In a preferred embodiment, at least one of the side, and optionally
each of the sides is marked (226a and 226b) to identify whether it
should contact the sacrum (as shown in FIG. 4, marked with "S") or
the ilium (as shown in FIG. 3A, marked with "I"). These markings
are merely illustrative and it is understandable that other
markings may be included to distinguish one side from the
other.
[0051] The cavity (290) defines a working space into which other
tools in the system are placed and used to prepare the SI joint
and/or stabilize the joint, optionally using an implant.
Preferably, at least one wall inside the cavity (290) contains a
long slot (292) running down its length to act as a guide for other
tools. Tools that are inserted into the working cannula preferably
contain a rail along an outside surface of the tool, which runs the
length of the body of the tool, where the rail is configured to
align with the slot on the working cannula. This allows the tool to
slide along the rail and remain in the appropriate position within
the cavity.
[0052] The cavity has a suitable size and shape to retain an
implant, such as a spacer. In some preferred embodiments, the
cavity is rectangular in shape to accommodate and retain a
rectangular shaped spacer. Other sized cavities are envisioned to
accommodate larger, longer, or smaller implants, or implants with
different shapes.
[0053] In some embodiments, the working cannula has holes or slots
(224, 232a, 232b) along its insertion portion, handle portion, or
both, which serve to reduce its weight and facilitate cleaning.
Typically the insertion portion is slightly smaller than the handle
portion.
[0054] In some embodiments, the handle portion (220) is typically
rounded, at least on its superior and inferior surfaces with a
plurality of ridges (222a, 222b) giving the operator a solid grip
of the instrument. The handle portion terminates at the distal end
(210). The distal end (210) of the working cannula has a larger,
flat surface area due to a flange (202) that protrudes, making the
distal end wider than the rest of the handle portion (220). The
larger surface area of the distal end allows a user to more easily
impact the end of the working cannula, if needed, such as with a
mallet.
[0055] Optionally, the handle portion of the working cannula is
configured to allow a tool to be mounted onto it to guide the
insertion of fixation elements. For example, the handle portion may
contain a slot (280), which is sized to receive a guide instrument
and secure the guide instrument to the handle. An exemplary guide
instrument is a lateral guide boom (300). The guide instrument can
be inserted via lateral insertion into the slot. The slot runs from
a first side (228) to a second side (229) of the handle portion.
The slot (280) may be located proximal to the flange (202).
[0056] C. SI Implant Insertion Tool
[0057] In some embodiments, the system includes an implant
insertion tool. Typically fixation of the SI joint requires the use
of a particular type of implant, i.e. a spacer to ensure the
appropriate spacing between the sacrum and the ilium during bone
growth and fusion. Preferably the system includes an implant
insertion tool, which can be used to hold an appropriately sized
spacer while impacting it into the prepared SI joint. While the
insertion tool can be used with any spacer formed from any suitable
material, the insertion tool is particularly useful for allograft
spacers. The insertion tool is able to insert the spacer and impact
it into the SI joint without the use of tapped holes or similar
high-stress areas, which could overload the fragile material of an
allograft spacer.
[0058] FIG. 5A is a schematic of an exemplary implant insertion
tool. FIG. 5B shows a cross-sectional view of the same tool.
Referring to FIGS. 5A and 5B, the implant insertion tool (500) has
a hollow body with width and height suitable for insertion into the
working cannula and removal therefrom. The insertion tool is
designed to hold implants of up to 50 mm in length. Its length is
directly dependent on the length of the working cannula and is
selected so that the proximal end is even with the end of the
working cannula, giving the surgeon control of the depth of implant
insertion.
[0059] The insertion tool (500) contains two main parts: a body
(520) and a slidable insertion ram (560). The body (520) has a
proximal insertion end (510), a handling region (550), a distal end
(555), and a central cavity that runs along a central axis of the
body.
[0060] The handling region preferably contains a plurality of
ridges (552a, 552b), at least along its superior and inferior
surfaces, giving the operator a solid grip of the instrument. The
handling region terminates at the distal end (555) and its proximal
end (556). The proximal end (556) is adjacent to the inserting
region (570), which is configured to fit in the insertion portion
(230) of the working cannula. The handling region is wider than the
insertion portion (230), thus the proximal end (556) of the
handling region acts as a stop to prevent over insertion of the
implant insertion tool within the working cannula.
[0061] The insertion end (510) contains a cavity (512) with
suitable dimensions to retain an implant during insertion. A
flexible, thin tab (515) is located on the superior surface of the
insertion end (510) and is configured to firmly capture the implant
in the tool by friction until pressed out by the slidable ram. The
tab is formed from a flexible material, such as stainless steel,
which allows the tab to be bent slightly to contact the edge of the
spacer, thereby holding the spacer in the cavity with friction.
FIG. 5B shows the insertion end without an implant. FIG. 5C shows
the insertion end with an implant retained therein.
[0062] One or more holes and/or slots (530a, 530b) may be included
along the sides of the body to reduce weight and facilitate
cleaning of the tool.
[0063] The slidable insertion ram (560) contains a distal end with
a cap (565) and a long body portion (562) that terminates in a
proximal end (564). The long body portion (562) is capable of being
fully contained inside the insertion tool in slidable relation to
the central cavity of the body. The slidable insertion ram is
configured to push the implant out of the insertion end and into
the joint. The proximal end (564) terminates in a surface (566),
which has a greater surface area than the tip (567) of the proximal
end of the body portion (562) to distribute the implant load evenly
over the posterior surface of the implant. Typically, the surface
(566) has a substantially rectangular shape.
[0064] The distal end of the slidable insertion ram (560) typically
has a large cylindrical cap (565) suitable for impacting with a
mallet.
[0065] The slidable insertion ram slides from a retracted position,
where the cap is farthest from the distal end (555) of the body
(520) to an operative position, where the cap is adjacent to the
distal end of the body and the body portion (562) is fully
contained within the body (520) of the insertion tool. When the
slidable ram is in the operative position, the implant is pushed
out of the insertion end of the tool and into the SI Joint
[0066] In preferred embodiments, the system also includes one or
more tools for preparing the SI Joint. Suitable tools include but
are not limited to a drill guide, a box chisel, and a rasp. One or
more of these tools may be used to prepare the SI Joint.
[0067] D. Drill Guide
[0068] In a preferred embodiment, the system includes a drill
guide. The drill guide is configured to fit within the cavity in
the working cannula. The drill guide contains at least two holes
that run the length of the guide. The holes are of a suitable size
for a standard drill bit, and are based on the width of the
implant. In a preferred embodiment, the implant is 6 mm wide.
[0069] Referring to FIG. 9, the drill guide (1100) is a long
substantially flat rectangular tool, with two overlapping holes
(1110a, 1110b) that are joined together and run the length of the
drill guide. Each hole has a diameter that is slightly larger than
the diameter of the drill being used. At the distal end (1120), the
drill guide contains a flange (1130) configured to rest on the
distal end (210) of the working cannula.
[0070] E. SI Joint Box Chisel
[0071] Optionally, the system includes a box chisel. Any suitable
box chisel that fits inside the working cannula can be used to
prepare the SI Joint. Referring to FIG. 7, the box chisel (900) has
a height and width based on the size of the implant and allows
insertion of the implant with minimal force but also prevents
breakage during insertion. The box chisel contains a sharp
rectangular cutting edge (912) at its proximal end (910).
Typically, the box chisel contains a box-shaped cavity (920) with
one or more slots or windows to collect and remove bone fragments
from the chisel. The box chisel preferably contains a long rail
(950) running down the length of its body, located on its outer
surface that acts as a guide within the working cannula. The rail
is configured to fit inside the long slot (292) located on a wall
of the cavity (290) of the working cannula, allowing the box chisel
to slide up and down along the slot.
[0072] Preferably, the box chisel contains a plurality of graduated
markings (930) etched on its side which correspond to the depth at
which the proximal end is located, which, when aligned with the
distal end of the working cannula, gives a surgeon control over the
cutting depth.
[0073] The box chisel terminates at its distal end (940). The
distal end of the box chisel is preferably configured for
attachment to other tools to aid in inserting or removing the box
chisel from the site. For example, the distal end of the box chisel
may be configured to attach to a slap handle for insertion or
removal of the tool.
[0074] F. SI Joint Rasp
[0075] Optionally, the system includes an SI Joint rasp. Any
suitable rasp that fits inside the working cannula can be used to
prepare the SI Joint. The joint rasp has suitable dimensions to fit
in and operate inside the working cannula.
[0076] Referring to FIG. 8, the joint rasp (1000) has a suitable
width, allowing it to operate within the working cannula. It may
have a rounded leading edge (1010), facilitating its insertion into
an unprepared cavity within the joint. Its dimensions are selected
to prepare the joint for insertion of the implant. Its height and
width are based on the size of the implant and it allows for
insertion of the implant with minimal force, but also prevents
breakage during insertion.
[0077] The proximal end (1020) of the rasp contains two generally
flat sides (1024 and 1026), each of which has a pattern of sharp
rectangular or diamond shaped structures (1022) protruding
therefrom, creating an abrasive surface. The abrasive surfaces aid
in cutting away uneven areas and preparing the two surfaces of the
joint for the implant.
[0078] The rasp has a long rail (1050) running down the length of
its body, located on an outer surface, that acts as a guide within
the working cannula. The rail is configured to fit inside the long
slot (292) located on a wall of the cavity (290) of the working
cannula, allowing the rasp to slide up and down along the
rectangular slot.
[0079] In some embodiments, the rasp has a plurality of graduated
markings (1030) etched on its side which correspond to the depth at
which the proximal end is located.
[0080] The rasp terminates at its distal end (1040). The distal end
of the rasp is preferably configured for attachment to other tools
to aid in inserting or removing the rasp from the site. For
example, the distal end of the rasp may be configured to attach to
a slap handle for insertion or removal of the tool.
[0081] G. Lateral Guide Boom
[0082] Optionally, the system includes a lateral guide boom. The
lateral guide boom is configured to direct the placement of lateral
fixation devices. The arm of the lateral boom guide is preferably
configured to be insertable into and removable from a rectangular
slot (280) in the distal end of the working cannula.
[0083] Referring to FIG. 3A, the lateral guide boom (300) can have
a curved L shape, the proximal end of which ends in a paddle-shaped
structure (320) with one or more drill holes (310a, 310b, 310c),
configured to hold bone screws. The lateral arm (330) may be
inserted into the rectangular slot (280) of the working cannula,
such that it is in slidable relation thereto.
[0084] The lateral guide boom locks in place in the working cannula
using a threaded capture clip. Multiple holes may be used to align
with the implant or to locations directly around the implant. Other
holes in the lateral guide boom provide access for screws to
non-critical areas of the SI joint, facilitating adequate fixation.
In certain embodiments, the system includes lateral guide booms of
various sizes that may be required based on the anatomy of the
patient.
[0085] H. Materials for Components of the System
[0086] The various components of the system are fabricated from
biocompatible materials suitable for implantation in a human body,
including but not limited to, metals, synthetic polymers, ceramics,
and/or their combinations, depending on the particular application
and/or preference of a medical practitioner. Further, the
components of the implant system can be manufactured via various
methods. For example, the implant may be manufactured and assembled
via injection-molding, insert-molding, co-extrusion, pultrusion,
transfer molding, overmolding, compression molding, 3-Dimensional
printing, dip-coating, spray-coating, powder-coating,
porous-coating, milling from a solid stock material and their
combinations.
III. Methods of Use
[0087] The system disclosed herein may be used to deliver any SI
joint implant or other fixation device(s) to the SI joint or SI
joint region. In a preferred embodiment, the system disclosed
herein is used to deliver the SI joint implants disclosed herein to
an SI joint of a patient in need thereof. The inferior inlet
approach provides access to the inferior aspect of the SI joint
while avoiding the nerves exiting the sacrum, as well as the
majority of blood vessels, ligaments, and muscles supporting the
hip and lumbar region of a patient. Further, the inferior inlet
approach allows for smaller incisions than the current MIS
techniques for accessing the SI joint. Therefore, the inferior
inlet approach reduces recovery time, risk of complications from
surgery, and reduces visibility of the incision once healed.
[0088] The inferior inlet approach is disclosed herein. For
delivery of the SI joint implant, the patient is preferably placed
in a prone position. If desired, fluoroscopy is used to visualize
the SI joint according to methods well established in the field.
Preferably, the position of the fluoroscopy is an inlet view of the
pelvis with an approximately 10-15 degree angle to isolate the
affected SI joint. This view provides a medical practitioner with a
straight view of the SI joint.
[0089] A. Accessing the Joint
[0090] A medical practitioner can access the SI joint through an
incision in the skin and soft tissue of a patient. The incision may
be of any size, but preferably the incision is less than one inch.
The incision is made in a region below the back of a patient.
Preferably, the incision is made in alignment with the longitudinal
axis of the SI joint. After the incision is made, a guide wire,
such as a K-Wire, or guide pin, is inserted through the incision
and advanced until it reaches the SI joint. The guide wire is used
to guide the sliding join finder to the desired site.
[0091] The sliding joint finder (100) is oriented over the guide
wire (or pin) and slides over the wire and into the joint until the
unilateral joint finder shelf (120) contacts the edge of the
posterior inferior iliac spine, thereby preventing further
insertion.
[0092] B. Inserting the Working Cannula
[0093] The working cannula (200) is inserted over the sliding joint
finder. Preferably, the working cannula is configured such that
when it is properly inserted in the SI Joint, the longer protrusion
is located at the superior end, while the shorter protrusion is
located at the inferior end of the SI joint (FIG. 10). If
necessary, the distal end (210) of the working cannula is impacted
with a device, such as a mallet, to push it into the SI Joint. The
working cannula is inserted into the body until the unilateral
shelf (260), which is located in the proximal end of the working
cannula, contacts the edge of the posterior inferior iliac spine,
thereby preventing further insertion.
[0094] After insertion of the working cannula, the sliding joint
finder and the K-Wire are removed, leaving the working cannula
docked in the SI joint (FIG. 10).
[0095] C. Preparing the SI Joint
[0096] An SI surface removal instrument is inserted into the
working cannula. In some embodiments, the instrument is a drill
guide (1100). In some embodiments, the instrument is a box chisel
(900). In some embodiments, the instrument is a rasp (1000).
[0097] When a drill guide is used, it is inserted in a first
position in the working cannula. The drill guide may have one, two,
three, or four overlapping holes (1110a, 1110b). In use, the drill
guide is inserted into the working cannula until it reaches the SI
joint. Then a suitable sized drill bit (attached to a drill) is
placed in the first hole and the bone is drilled to remove the
bone. Preferably a stop portion is provided along the drill bit at
the distal end of the drill guide to prevent over insertion of the
drill bit (and over drilling). The drill bit is then moved to the
second hole and the second hole is drilled. After both holes are
drilled, the drill guide is removed from the working cannula,
rotated 180 degrees axially, and reinserted into the working
cannula. The drilling procedure described above is repeated to
drill two additional holes in the bone.
[0098] Using above-mentioned tools, cartilaginous/fibrous tissue on
either side of the SI joint is removed. This results in a suitable
environment for bone growth to promote fusion of the SI joint. If
needed, a rasp or other suitable device is inserted into the
working cannula for additional preparation of the SI joint space.
The rasp may be used to roughen the bone surface to prepare for
fusion. An exemplary rasp is illustrated in FIG. 8.
[0099] D. Inserting the Implant
[0100] If necessary, after the SI Joint is prepared, an implant is
inserted and then fixed in the prepared SI Joint.
[0101] First the desired size and shape implant is selected and
placed in the insertion end (510) of the implant insertion tool
(500). An implant having the desired size and shape (600a, 600b,
600c, 600d) is loaded into the implant insertion tool. In some
embodiments, two or three implants are loaded at one time. In some
embodiments, the implants are of varying lengths.
[0102] The proximal end of the slidable insertion guide is inserted
into a hole at the end of the implant.
[0103] When the implant is placed in the insertion end (510) of the
implant insertion tool (500), the cap (565) of the slidable
insertion guide is in its retracted position.
[0104] Then the insertion tool (500) is inserted into the working
cannula until the proximal end (556) of the handling region (550)
contacts the flange (202) at the distal end (210) of the working
cannula. In this position, the insertion end (510) is located in
the proximal end (240) of the working cannula and is located
between the superior and inferior protrusions (240a, 240b).
[0105] Then a user pushes the cap (565) of the slidable ram into
its operative position to deliver the implant to the SI Joint. When
the cap is pushed, the body portion (562) slides along the cavity
until the rectangular surface (566) of the proximal end contacts
and pushes the posterior surface of the implant (560).
[0106] When the cap (565) is pushed into its operative position,
the cap is adjacent to the distal end of the body, and the implant
is pushed out of the insertion end of the tool and into the SI
Joint. The implant is located between the protrusions of the
working cannula.
[0107] The location of the implant can be confirmed by any suitable
imaging technique, such as X-Ray, CT scan, or MM.
[0108] 1. Implants
[0109] The implant can have any suitable shape for use in the SI
joint. Preferably the implant is a spacer. Referring to FIGS.
6A-6D, the spacer (600a, 600b, 600c, 600d) may be rectangular in
shape, with the height being more than twice the width. In some
embodiments the spacer is 6 mm wide, allowing it to fit into the
very small space between the bones of the sacrum and ilium. This
allows for minimal removal of cortical bone from each face of the
joint. In some embodiments the implant is 20 mm, 25 mm, 30 mm, 35
mm, or 40 mm in length, thus accounting for anatomical differences.
In some embodiments the upper and lower sides of the spacer have
triangular projections (640), which prevent posterior migration of
the spacer, once in the SI joint. In some embodiments the implant
has rounded corners (630), allowing for ease of insertion into the
joint, and allowing the implant to fit easily into the insertion
tool. The implant may also have a series of holes (610, 620) along
its length, allowing for insertion of bone graft or bone graft
substitute. In some embodiments the holes are circular, as shown in
FIGS. 6A-6D. In some embodiments the holes are rectangular.
[0110] a) Materials
[0111] The implant is fabricated from biocompatible materials
suitable for implantation in a human body, including but not
limited to, allograft or autograft bone, metals, synthetic
polymers, ceramics, and/or their combinations, depending on the
particular application and/or preference of a medical practitioner.
Further, the components of the implant system can be manufactured
via various methods. Alternatively, the implant may be manufactured
and assembled via injection-molding, insert-molding, co-extrusion,
pultrusion, transfer molding, overmolding, compression molding,
3-Dimensional printing, dip-coating, spray-coating, powder-coating,
porous-coating, milling from a solid stock material and their
combinations.
[0112] In the preferred embodiment, the implant is formed from
allograft bone. In other embodiments, the implant is fabricated
from another biocompatible material, such as commercially pure
titanium, titanium alloys, Grade 5 titanium, super-elastic titanium
alloys, cobalt-chrome alloys, stainless steel alloys, superelastic
metallic alloys (e.g. nitinol, Elgiloy (a Co--Cr--Ni Alloy)),
carbon fiber, thermoplastics such as polyaryletherketone (PAEK),
including polyetheretherketone (PEEK) and polyetherketone (PEK),
carbon fiber reinforced PEEK composites, PEEK-BaSO.sub.4
composites, ceramics and composites thereof, such as calcium
phosphate (e.g. SKELITE.TM.), rigid polymers including
polyphenylene, polyamide, polyimide polyetherimide, polyetherimide,
polyethylene, polyurethanes of any durometer, epoxy, or silicone.
Different components of the SI implant system may be fabricated
from a heterogeneous material, such as a combination of two or more
of the above described materials to achieve various desired
characteristics such as strength, rigidity, elasticity, compliance,
biomechanical performance, durability and radiolucency or imaging
preference.
[0113] ii) Cavity Filler
[0114] In certain embodiments the implant has a cavity. In these
embodiments, the implant cavity may be filled with suitable
biocompatible materials to facilitate joint fixation or fusion.
Suitable biocompatible materials include, but are not limited to
bone material including autograft, allograft, xenograft or
transgenic cortical and/or corticocancellous bone, and tissue
growth or differentiation factors, partially resorbable materials,
such as composite of metals and calcium based ceramics, composites
of PEEK and calcium based ceramics, composites of PEEK with
resorbable polymers, totally resorbable materials, such as calcium
based ceramics such as calcium phosphate, tri-calcium phosphate
(TCP), hydroxyapatite (HA)-TCP, calcium sulfate, or other
resorbable polymers such as polylactide, polyglycolide,
polytyrosine carbonate, and their combinations.
[0115] b) Active Agents
[0116] Optionally, a wide range of bioactive factors can be applied
in the form of a coating or otherwise integrated into the surface
of the implant to aid in SI joint fixation by inducing and
supporting healing, repair and regeneration of soft and hard
tissue, in particular, bone and cartilage. Suitable factors
include, but are not limited to, autologous bone from ipsilateral
posterior superior iliac spine, nucleotides, peptides, proteins,
antibodies, biocompatible chemical compounds, and other
pharmaceuticals. Preferred bioactive factors include parathyroid
hormones (PTHs), platelet-derived growth factors (PDGFs),
Transforming growth factor betas (TGF .beta.s), bone morphogenetic
proteins (BMPs), vascular endothelial growth factor (VEGFs),
Insulin-like growth factors (IGFs), Fibroblast Growth Factors
(FGFs), and variants having the same effect in the human or animal
body. Most preferred bioactive factors include autologous bone
graft, PDGF AB, PTH1-34, BMP2, BMP 7, TGF .beta.1, TGF .beta.3,
VEGF 121, and VEGF 110. Other suitable bioactive factors include,
but are not limited to, antibiotics, chemotherapeutics, analgesics,
anesthetics, anti-proliferating agents, and immunomodulators.
[0117] E. Fixation of Implant
[0118] Optionally, after the correct location of implant or
implants has been confirmed, one or more fixation elements may be
inserted. An SI joint implant may be secured within the SI joint by
one or more, typically two or more, fixation elements. Typically,
the fixation elements are inserted adjacent to the implant.
Optionally, the fixation elements can be inserted either through
the prepared holes of an implant, or through a new hole drilled
directly through the implant, which is intended to provide
compression and to fix the implant within the joint space.
[0119] For example, imaging techniques can be used to determine the
locations for fixation screws for fixation of the implant. Using
imaging techniques, K-wires may be inserted into the patient's body
until they reach the implant. Next cannulated screws are placed
over the K-wires and turned until they reach the desired location.
One or more of the screws typically pass through a portion of the
implant and into the adjacent bone to fix the implant in place.
[0120] Alternatively, after the correct location of implant or
implants has been confirmed, a lateral guide boom (300) can be used
to determine the exact location of the lateral fixation screws.
[0121] The lateral guide boom has a curved L-shape, that, once
inserted into the lateral rectangular slot (280) of the working
cannula, has an arm (330) running perpendicular, and a second arm
(340) located parallel to the working cannula. The arm (340)
running parallel to the working cannula ends in a paddle-like
structure (320) that aligns with the two protrusions (240a, 240b)
of the working cannula, as well as with the implant. The
paddle-like structure (320) has holes (310a, 310b, 310c) that align
with the location for screw holes for fixation of the implant.
[0122] The paddle structure is positioned outside the body,
directly above the location of the implant. Using imaging
techniques, K-wires are inserted through the holes and into the
patient's body until they reach the implant. Then, the lateral
guide boom is removed from the working cannula. Next cannulated
screws are placed over the K-wires and turned until they reach the
desired location. One or more of the screws typically pass through
a portion of the implant and into the adjacent bone to fix the
implant in place.
[0123] 1. Fixation Elements
[0124] A fixation element is any suitable element for attaching an
implant, such as a spacer, to a bone, such as a screw, nail, or
rod. Preferably, the fixation elements are titanium bone screws;
preferably the bone screws are cannulated.
[0125] The bone screws can be of any standard type, but are
preferably self-tapping, cannulated, low-profile, hexalobe or
hexagon drive, flat-head type of bone screw. In other embodiments,
the fixation elements are made of any suitable biocompatible
material, including non-biodegradable and biodegradable
materials.
[0126] In other embodiments the fixation elements are pins, rods,
or other suitable structures for fixating the implant within the
joint space.
[0127] Fixation elements can be fabricated from biocompatible
materials such as titanium, titanium alloys, Grade 5 titanium,
super-elastic titanium alloys, cobalt-chrome alloys, stainless
steel alloys, superelastic metallic alloys (e.g. nitinol, (e.g.
nitinol, Elgiloy (a Co--Cr--Ni Alloy)), stainless steel, carbon
fiber or combinations thereof.
[0128] Optionally, this SI joint system can be used in conjunction
with a separate system for inserting fixation elements.
IV. Kits
[0129] The system described herein may be provided in a kit for
preparing the SI joint and, optionally, delivering an implant to
the SI joint. In a preferred embodiment, the kit contains a sliding
joint finder and a working cannula. The kit may also contain an
implant insertion tool. The kit may also contain one or more tools
for preparing the SI Joint, such as a drill guide and/or an SI
joint box Chisel.
[0130] Optionally, the kit contains additional components, such as
an SI joint rasp, a guide for fixation elements, and/or one or more
fixation elements.
[0131] The kit typically contains instructions for care and use of
the system.
[0132] In one embodiment, the kit can include tools and materials
for inserting bone graft material. For example, the kit can include
a syringe or other apparatus for injecting bone graft material.
[0133] In some embodiments, one or more implants are provided in a
kit with the system described herein. Preferably, the implant is
provided separately from the tools used for preparing and
implanting the implants. In a preferred embodiment, an implant
provided separately is sterilely packed and preserved in a saline
solution, lyophilized, or preserved by some other means. A variety
of different sized implants are typically provided to allow for
selection of the properly sized implant for an individual due to
diversity in patients' anatomies.
[0134] While several embodiments are described in connection with
the figures described herein, there is no intent to limit the
disclosure to the embodiment or embodiments illustrated
therein.
[0135] Unless defined otherwise, all technical and scientific terms
used herein have the same meanings as commonly understood by one of
skill in the art to which the disclosed invention belongs.
Publications cited herein and the materials for which they are
cited are specifically incorporated by reference.
[0136] Those skilled in the art will recognize, or be able to
ascertain using no more than routine experimentation, many
equivalents to the specific embodiments of the invention described
herein. Such equivalents are intended to be encompassed by the
following claims.
* * * * *