U.S. patent application number 16/003636 was filed with the patent office on 2018-10-11 for staples for generating and applying compression within a body.
The applicant listed for this patent is ARTHREX, INC.. Invention is credited to Alexander DelMonaco, Robert Devaney, Matthew Fonte, Daniel Morgan, Kaitlyn Nealon, Matthew Palmer.
Application Number | 20180289366 16/003636 |
Document ID | / |
Family ID | 53044398 |
Filed Date | 2018-10-11 |
United States Patent
Application |
20180289366 |
Kind Code |
A1 |
Morgan; Daniel ; et
al. |
October 11, 2018 |
STAPLES FOR GENERATING AND APPLYING COMPRESSION WITHIN A BODY
Abstract
Apparatus for generating, applying and maintaining compression
to a site in a human or animal body, the apparatus comprising: a
staple comprising: a bridge configured to be elastically bendable;
a first leg connected to the bridge by a first hinge region
configured to be elastically bendable; and a second leg connected
to the bridge by a second hinge region configured to be elastically
bendable; wherein the first hinge region comprises a first hole
configured to mate with a first element of a delivery device and
the second hinge region comprises a second hole configured to mate
with a second element of a delivery device; and wherein the first
and second legs are angled toward one another when they are in an
unstrained state; whereby, when the staple is mounted to a delivery
device so that the first hole of the first hinge region mates with
a first element of a delivery device and the second hole of the
second hinge region mates with a second element of a delivery
device, and when the delivery device applies a force to the bridge
of the staple so as to reconfigure the bridge of the staple, the
first and second legs are pivoted away from one another toward a
parallel disposition.
Inventors: |
Morgan; Daniel; (Salem,
MA) ; Palmer; Matthew; (Cambridge, MA) ;
Fonte; Matthew; (Concord, MA) ; Devaney; Robert;
(Auburndale, MA) ; Nealon; Kaitlyn; (Boston,
MA) ; DelMonaco; Alexander; (Billerica, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ARTHREX, INC. |
Naples |
FL |
US |
|
|
Family ID: |
53044398 |
Appl. No.: |
16/003636 |
Filed: |
June 8, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15079770 |
Mar 24, 2016 |
10016198 |
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16003636 |
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|
14540351 |
Nov 13, 2014 |
9855036 |
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15079770 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/0641 20130101;
A61B 17/7266 20130101; A61B 2017/00946 20130101; A61B 17/7291
20130101; A61B 2017/0645 20130101; A61B 17/0682 20130101; A61B
2017/00867 20130101; A61B 2017/00871 20130101; A61B 17/068
20130101; A61B 17/0642 20130101 |
International
Class: |
A61B 17/068 20060101
A61B017/068; A61B 17/064 20060101 A61B017/064 |
Claims
1. Apparatus for generating, applying and maintaining compression
to a site in a human or animal body, the apparatus comprising: a
staple comprising: a bridge configured to be elastically bendable;
a first leg connected to the bridge by a first hinge region
configured to be elastically bendable; and a second leg connected
to the bridge by a second hinge region configured to be elastically
bendable; wherein the first hinge region comprises a first hole
configured to mate with a first element of a delivery device and
the second hinge region comprises a second hole configured to mate
with a second element of a delivery device; and wherein the first
and second legs are angled toward one another when they are in an
unstrained state; whereby, when the staple is mounted to a delivery
device so that the first hole of the first hinge region mates with
a first element of a delivery device and the second hole of the
second hinge region mates with a second element of a delivery
device, and when the delivery device applies a force to the bridge
of the staple so as to reconfigure the bridge of the staple, the
first and second legs are pivoted away from one another toward a
parallel disposition.
2. Apparatus according to claim 1 wherein the bridge has a
non-linear configuration when it is in an unstrained state, and
further wherein when a delivery device applies a force to the
bridge of a staple, the bridge is reconfigured from a non-linear
configuration toward a linear configuration.
3. Apparatus according to claim 2 wherein the staple comprises a
shape memory material.
4. Apparatus according to claim 3 wherein the shape memory material
comprises Nitinol.
5. Apparatus according to claim 2 wherein the bridge has a curved
configuration when the bridge is in an unstrained state.
6. Apparatus according to claim 5 wherein the bridge is curved away
from the first and second legs when the bridge is in an unstrained
state.
7. Apparatus according to claim 2 wherein the bridge has a stepped
configuration when the bridge is in an unstrained state.
8. Apparatus according to claim 2 wherein the staple comprises more
than two legs.
9. Apparatus according to claim 2 further comprising a delivery
device, the delivery device comprising: a first element sized to be
received in the first hole of the first hinge region of the staple;
a second element sized to be received in the second hole of the
second hinge region of the staple; and a plunger adapted to apply a
force to the bridge of the staple so as to reconfigure the bridge
of the staple from a non-linear configuration toward a linear
configuration.
10. Apparatus according to claim 9 wherein the delivery device
comprises a body, the first element is mounted to a first arm which
is pivotally connected to the body, the second element is mounted
to a second arm which is pivotally connected to the body, and the
plunger is movably mounted to the body.
11. Apparatus according to claim 9 wherein the plunger is movably
mounted to the body so as to allow the user to control the amount
of force applied to the bridge of the staple.
12. Apparatus according to claim 9 wherein the staple and the
delivery device are packaged as a sterilized kit.
13. A method for generating, applying and maintaining compression
to a site in a human or animal body, the method comprising:
providing a staple comprising: a bridge configured to be
elastically bendable; a first leg connected to the bridge by a
first hinge region configured to be elastically bendable; and a
second leg connected to the bridge by a second hinge region
configured to be elastically bendable; wherein the first hinge
region comprises a first hole configured to mate with a first
element of a delivery device and the second hinge region comprises
a second hole configured to mate with a second element of a
delivery device; and wherein the first and second legs are angled
toward one another when they are in an unstrained state; providing
a delivery device comprising: a first element sized to be received
in the first hole of the first hinge region of the staple; a second
element sized to be received in the second hole of the second hinge
region of the staple; and a plunger adapted to apply a force to the
bridge of the staple so as to reconfigure the bridge of the staple;
mounting the staple to the delivery device so that the first hole
of the first hinge region mates with the first element of the
delivery device and the second hole of the second hinge region
mates with the second element of the delivery device; applying a
force to the bridge of the staple with the plunger of the delivery
device so as to reconfigure the bridge of the staple such that the
first and second legs are pivoted away from one another toward a
parallel disposition; inserting the staple into a site in a human
or animal body; withdrawing the plunger of the delivery device from
the bridge of the staple so as to cause the staple to apply
compression to the site in a human or animal body as the staple
reconfigures; and releasing the staple from the delivery
device.
14. A method according to claim 13 wherein the bridge has a
non-linear configuration when it is in an unstrained state, and
further wherein when the delivery device applies a force to the
bridge of a staple, the bridge is reconfigured from a non-linear
configuration toward a linear configuration.
15. A method according to claim 14 wherein the staple comprises a
shape memory material.
16. A method according to claim 15 wherein the shape memory
material comprises Nitinol.
17. A method according to claim 14 wherein the bridge has a curved
configuration when the bridge is in an unstrained state.
18. A method according to claim 14 wherein the bridge is curved
away from the first and second legs when the bridge is in an
unstrained state.
19. A method according to claim 14 wherein the bridge has a stepped
configuration when the bridge is in an unstrained state.
20. A method according to claim 14 wherein the staple comprises
more than two legs.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This patent application:
[0002] (i) is a continuation of pending prior U.S. patent
application Ser. No. 15/079,770 filed on Mar. 24, 2016 by MX
Orthopedics, Corp. and Daniel Morgan et al. for STAPLES FOR
GENERATING AND APPLYING COMPRESSION WITHIN A BODY (Attorney's
docket No. 67486-025PUS4).
[0003] (ii) is a continuation-in-part of pending prior U.S. patent
application Ser. No. 14/540,351, filed Nov. 13, 2014 by MX
Orthopedics, Corp. and Matthew Palmer et al. for STAPLES FOR
GENERATING AND APPLYING COMPRESSION WITHIN A BODY (Attorney's
Docket No. FONTE-52);
[0004] (iii) claims benefit of pending prior U.S. Provisional
Patent Application Ser. No. 62/137,496, filed Mar. 24, 2015 by MX
Orthopedics, Corp. and Daniel Morgan et al. for STAPLES THAT DO NOT
NEED TO BE TAMPED TO BE FULLY SEATED FOR GENERATING AND APPLYING
COMPRESSION WITHIN A BODY (Attorney's Docket No. FONTE-55
PROV);
[0005] (iv) claims benefit of pending prior U.S. Provisional Patent
Application Ser. No. 62/137,570, filed Mar. 24, 2015 by MX
Orthopedics, Corp. and Daniel Morgan et al. for STAPLES THAT DO NOT
NEED TO BE TAMPED TO BE FULLY SEATED FOR GENERATING AND APPLYING
COMPRESSION WITHIN A BODY (Attorney's Docket No. FONTE-56 PROV);
and
[0006] (v) claims benefit of pending prior U.S. Provisional Patent
Application Ser. No. 62/238,472, filed Oct. 7, 2015 by MX
Orthopedics, Corp. and Matthew Palmer et al. for DEVICES FOR
CONTROLLING THE UNLOADING OF SUPERELASTIC AND SHAPE MEMORY
ORTHOPEDIC IMPLANTS (Attorney's Docket No. FONTE-69 PROV).
[0007] The five (5) above-identified patent applications are hereby
incorporated herein by reference.
FIELD OF THE INVENTION
[0008] The present invention relates to staples for generating,
applying, and maintaining compression to a site in a human or
animal body in order to facilitate healing of diseased or damaged
tissue. The invention finds particular utility in the field of
orthopedics and specifically for reducing fractures and maintaining
compression between bone fragments, and/or for reducing openings
and maintaining compression between bone segments in osteotomies,
and/or for inducing fusion across the bones of a joint in an
arthrodesis. While the invention has application throughout the
body, its utility will be illustrated herein in the context of the
repair of fractured or displaced bone tissue, such as during an
Akin Osteotomy of the foot or an Isolated Lunocapitate Arthrodesis
of the hand/wrist.
BACKGROUND OF THE INVENTION
[0009] In the field of orthopedic surgery it is common to rejoin
broken bones. The success of the surgical procedure often depends
on the ability to re-approximate the bone fragments, the amount of
compression achieved between the bone fragments, and the ability to
sustain that compression over a period of time. If the surgeon is
unable to bring the bone fragments into close contact, a gap will
exist between the bone fragments and the bone tissue will need to
fill that gap before complete healing can take place. Furthermore,
gaps between bone fragments that are too large allow motion to
occur between the bone fragments, disrupting the healing tissue and
thus slowing the healing process. Optimal healing requires that the
bone fragments be in close contact with each other, and for a
compressive load to be applied and maintained between the bone
fragments. Compressive strain between bone fragments has been found
to accelerate the healing process in accordance with Wolf's
Law.
[0010] Broken bones can be rejoined using staples. Staples are
formed from a plurality of legs (typically two legs, although
sometimes more) connected together by a bridge. Staples are
typically manufactured from stainless steel alloys, titanium alloys
or Nitinol, a shape memory alloy. The legs of the staples are
inserted into pre-drilled holes on either side of the fracture
line, with the bridge of the staple spanning the fracture line.
[0011] Existing staples need to be impacted so as to make the
bottom of the staple bridge sit flush with the bone surface
following implantation of the staple legs into the pre-drilled
holes. This is because current staples and their associated
delivery devices are typically designed to grip the staples under
the bridge of the staple. After the staple has been deployed from
the delivery device, there is a gap between the bottom of the
bridge and the top surface of the bone. A tamp is typically used to
fully seat the staple bridge against the bone surface. Thus, an
additional step (i.e., the tamping step) is required. In addition,
the action of tamping can cause the bone fragments to move out of
position, impairing healing.
[0012] Furthermore, current staple systems do not allow the surgeon
to control the amount of compression that the staple will exert
when it is released from the delivery device. While the shape
memory and superelastic properties allow Nitinol staples to pull
together the opposing bone fragments, the recovery forces and
recoverable strain generated by these staples may be too great and
may result in the staples "tearing through" the bone tissue and
thus not providing a means to generate and maintain compression
between the bone fragments.
[0013] Additionally, current staple systems do not allow the
surgeon to control the rate at which the staple loads the bone when
it is removed from the delivery device. Current delivery devices
load the bone nearly instantaneously. This may result in a large
force impulse as the staple's legs rapidly undergo shape recovery.
This force impulse may damage the bone and result in impaired
healing.
[0014] Current staple systems also do not allow the surgeon to
control the extent to which the staple's legs are opened. This can
make it particularly difficult to implant the staple into the
pre-drilled holes if the holes were drilled slightly out of
position. More particularly, if the pre-drilled holes are slightly
too close together or slightly too far apart, it may be difficult
to fit the staple legs into the holes and may result in impaired
healing.
[0015] Finally, current staple systems do not allow for the staple
to be easily removed following implantation. Since the staples are
tamped flush with the bone surface, there is no easy way for
surgeons to grip and remove current staples. It is very
time-consuming for surgeons to pry out deployed staples and it is
difficult to cut deployed staples for removal. In addition, these
actions may damage the underlying bone, thus impairing healing and
may result in the patient needing to be under anesthesia for a
longer period of time.
[0016] Thus there exists a significant clinical need for a new
staple and a new associated delivery device to implant the staple
flush with the bone surface without the need for tamping to fully
seat the staple. Additionally, there is a significant clinical need
for a staple system that allows the surgeon to control the amount
of compression the staple will generate across the fracture line
after the staple has been implanted into bone, to control the rate
at which the staple loads the bone, to allow the surgeon to adjust
opening the staple legs for proper alignment with pre-drilled
holes, and to allow the staple to be easily removed from the bone
if desired.
SUMMARY OF THE INVENTION
[0017] Additionally, it is possible that where the staple comprises
a malleable bridge with two elastic legs, the staple can be
inserted into the fracture site prior to bending the bridge. The
bridge can be bent after implantation using a tamp-like device of
the sort known in the art.
[0018] The present invention provides a novel fixation device which
is able to bring bone fragments into close proximity with each
other, generate a compressive load across a fracture line and
maintain that compressive load across the fracture line while
healing occurs.
[0019] Among other things, the present invention comprises the
provision and use of a novel staple which is manufactured from a
shape memory material (e.g., a material capable of exhibiting
superelasticity and/or a temperature-induced shape change). The
shape memory material may comprise a metal alloy (e.g., Nitinol) or
a polymer (e.g., appropriately processed PEEK). Alternatively, the
novel staple may be manufactured from another suitable material,
e.g., stainless steel, titanium, etc. The staple is designed to
reduce fractures and generate and maintain compression across a
fracture line between the bone fragments to aid in fracture
healing. Note that in the preferred form of the invention, the
staple is designed to generate and maintain compression between
both the cortical bone and the cancellous bone of the bone
fragments so as to promote effective healing.
[0020] In one form of the invention, the staple comprises an
elastic bridge and two elastic legs. The bridge and the legs meet
at a pair of curved hinge regions which are also elastic. The hinge
regions comprise holes that run through the full thickness of the
hinge regions and are used to mate the staple to a delivery device.
In the unrestrained state, the legs of the staple are oriented
inwardly with an angle of less than 90.degree. (relative to the
bridge) and the bridge of the staple is bowed upward. Prior to
implantation, the bridge of the staple can be reversibly bent and
the legs of the staple can be reversibly pivoted (e.g., by bending
at the elastic hinge regions) so that the bridge is more linear and
the legs are substantially perpendicular to the longitudinal axis
of the bridge. This allows for insertion of the staple into a
prepared fracture site. A delivery device that mates with the holes
in the staple's hinge region may be used to strain the staple, or
the delivery device may act as a constraint, with the staple being
strained while not loaded on the delivery device and then loaded
onto the delivery device in the strained state. The constrained
staple can then be inserted into the prepared fracture site (e.g.,
by positioning the staple's legs into pre-drilled holes on either
side of the fracture line) and the staple can be released from the
delivery device. Since the delivery device engages the staple at
the holes in the hinge region, the staple can be fully seated
during implantation (i.e., the bottom of the bridge can sit on the
surface of the bone) and does not need to be tamped in order to
fully seat the staple. Releasing the staple from the delivery
device allows the bridge and legs of the staple to attempt to
return to their original unrestrained state, thereby generating and
maintaining a compressive load while healing occurs.
[0021] In one preferred form of the invention, there is provided
apparatus for generating, applying and maintaining compression to a
site in a human or animal body, the apparatus comprising: a staple
comprising: a bridge configured to be elastically bendable; a first
leg connected to the bridge by a first hinge region configured to
be elastically bendable; and a second leg connected to the bridge
by a second hinge region configured to be elastically bendable;
wherein the first hinge region comprises a first hole configured to
mate with a first element of a delivery device and the second hinge
region comprises a second hole configured to mate with a second
element of a delivery device; and wherein the first and second legs
are angled toward one another when they are in an unstrained state;
whereby, when the staple is mounted to a delivery device so that
the first hole of the first hinge region mates with a first element
of a delivery device and the second hole of the second hinge region
mates with a second element of a delivery device, and when the
delivery device applies a force to the bridge of the staple so as
to reconfigure the bridge of the staple, the first and second legs
are pivoted away from one another toward a parallel
disposition.
[0022] In another preferred form of the invention, there is
provided a method for generating, applying and maintaining
compression to a site in a human or animal body, the method
comprising: providing a staple comprising: a bridge configured to
be elastically bendable; a first leg connected to the bridge by a
first hinge region configured to be elastically bendable; and a
second leg connected to the bridge by a second hinge region
configured to be elastically bendable; wherein the first hinge
region comprises a first hole configured to mate with a first
element of a delivery device and the second hinge region comprises
a second hole configured to mate with a second element of a
delivery device; and wherein the first and second legs are angled
toward one another when they are in an unstrained state; providing
a delivery device comprising: a first element sized to be received
in the first hole of the first hinge region of the staple; a second
element sized to be received in the second hole of the second hinge
region of the staple; and a plunger adapted to apply a force to the
bridge of the staple so as to reconfigure the bridge of the staple;
mounting the staple to the delivery device so that the first hole
of the first hinge region mates with the first element of the
delivery device and the second hole of the second hinge region
mates with the second element of the delivery device; applying a
force to the bridge of the staple with the plunger of the delivery
device so as to reconfigure the bridge of the staple such that the
first and second legs are pivoted away from one another toward a
parallel disposition; inserting the staple into a site in a human
or animal body; withdrawing the plunger of the delivery device from
the bridge of the staple so as to cause the staple to apply
compression to the site in a human or animal body as the staple
reconfigures; and releasing the staple from the delivery
device.
[0023] In another preferred form of the invention, there is
provided a staple comprising: a bridge configured to be elastically
bendable; a first leg connected to the bridge by a first hinge
region configured to be elastically bendable; and a second leg
connected to the bridge by a second hinge region configured to be
elastically bendable; wherein the first hinge region comprises a
first hole and the second hinge region comprises a second hole; and
wherein the bridge has a non-linear configuration when it is in an
unstrained state, and wherein the first and second legs are angled
toward one another when they are in an unstrained state.
[0024] In another preferred form of the invention, there is
provided apparatus for securing tissue to a site in a human or
animal body, the apparatus comprising: a staple comprising: a
bridge configured to be elastically bendable; a first leg connected
to the bridge by a first hinge region configured to be elastically
bendable; and a second leg connected to the bridge by a second
hinge region configured to be elastically bendable; wherein the
first hinge region comprises a first hole and the second hinge
region comprises a second hole; and wherein the bridge has a
non-linear configuration when it is in an unstrained state, and
wherein the first and second legs are angled toward one another
when they are in an unstrained state; and at least one suture
extending through (i) at least one of the first hole and the second
hole, and (ii) the tissue to be secured to the site in a human or
animal body.
[0025] In another preferred form of the invention, there is
provided a staple comprising: a bridge configured to be plastically
deformable; a first leg connected to the bridge by a first hinge
region configured to be elastically bendable; and a second leg
connected to the bridge by a second hinge region configured to be
elastically bendable; wherein the first hinge region comprises a
first hole and the second hinge region comprises a second hole; and
wherein the bridge has a non-linear configuration when it is in an
unstrained state, and wherein the first and second legs are angled
toward one another when they are in an unstrained state.
[0026] In another preferred form of the invention, there is
provided a staple comprising: a bridge configured to be elastic; a
first leg connected to the bridge by a first hinge region
configured to be elastically bendable; and a second leg connected
to the bridge by a second hinge region configured to be elastically
bendable; wherein the first hinge region comprises a first hole and
the second hinge region comprises a second hole; and wherein the
first and second legs are angled toward one another when they are
in an unstrained state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] These and other objects and features of the present
invention will be more fully disclosed or rendered obvious by the
following detailed description of the preferred embodiments of the
invention, which is to be considered together with the accompanying
drawings wherein like numbers refer to like parts, and further
wherein:
[0028] FIG. 1 is a schematic view of a novel staple formed in
accordance with the present invention, wherein the staple comprises
a bridge which is capable of being elastically bent and legs which
are capable of being elastically pivoted about elastic hinge
regions, and further wherein the staple is shown in its unstrained
condition;
[0029] FIG. 2 is a schematic view of the novel staple shown in FIG.
1, wherein the bridge of the staple has been elastically bent
(i.e., made to be more linear) and the legs of the staple have been
elastically pivoted outwards (e.g., by bending at the elastic hinge
regions) so as to be perpendicular to the bridge;
[0030] FIG. 3 is a schematic view showing how the elastically bent
staple of FIG. 2 will have its legs "kick inward" when the strain
on the staple is removed;
[0031] FIGS. 4, 4A, 4B, 5, 6, 6A and 6B are schematic views showing
a novel delivery device which may be used with the novel staple
shown in FIG. 1 to strain and constrain the staple (e.g., with the
staple legs perpendicular to the staple bridge);
[0032] FIGS. 7 and 8 are schematic views showing the delivery
device of FIGS. 4, 4A, 4B, 5, 6, 6A and 6B being used with the
novel staple shown in FIG. 1 to elastically bend the bridge of the
staple and elastically pivot the legs of the staple (e.g., by
bending at the elastic hinge regions);
[0033] FIGS. 9 and 10 are schematic views showing how the novel
staple of FIG. 1 may be used to generate and maintain compression
between bone fragments so as to aid in fracture healing;
[0034] FIGS. 11-13 are schematic views showing another novel staple
formed in accordance with the present invention, wherein the novel
staple comprises a bridge which is capable of being elastically
bent and legs which are capable of being elastically pivoted about
elastic hinge regions--the novel staple of FIGS. 11-13 has a
concave bridge specifically engineered to match the anatomy of the
fracture site (e.g., an Akin Osteotomy site), where FIG. 11 shows
the staple in its unstrained condition, FIG. 12 shows the staple
strained with its bridge elastically bent (i.e., made to be more
concave) and its legs pivoted outwards (e.g., by bending at the
elastic hinge regions) so as to be perpendicular to the bridge, and
FIG. 13 is a schematic view showing how the elastically bent staple
of FIG. 12 will have its legs "kick inward" when the strain on the
staple is removed;
[0035] FIGS. 14-16 are schematic views showing still another novel
staple formed in accordance with the present invention, wherein the
novel staple comprises a sloped bridge which is capable of being
elastically bent and legs which are capable of being elastically
pivoted about elastic hinge regions--the novel staple of this
design has a slanted bridge specifically engineered to match the
anatomy of the fracture site (e.g., an Akin Osteotomy site), where
FIG. 14 shows the staple in its unstrained condition, FIG. 15 shows
the staple strained with its bridge elastically bent (i.e., made to
be more sloped) and its legs pivoted outwards (e.g., by bending at
the elastic hinge regions) so as to be parallel with each other,
and FIG. 16 is a schematic view showing how the elastically bent
staple of FIG. 15 will have its legs "kick inward" when the strain
on the staple is removed;
[0036] FIGS. 17-19 are schematic views showing yet another novel
staple formed in accordance with the present invention, wherein the
novel staple comprises a bridge which is capable of being
elastically bent and legs which are capable of being elastically
pivoted about elastic hinge regions--the staple of this design has
a stepped bridge specifically engineered to match the anatomy of
the fracture site (e.g., sliding calcaneal osteotomies,
calcaneocuboid fusions, Lapidus procedures, etc.), where FIG. 17
shows the staple in its unstrained condition, FIG. 18 shows the
staple strained with its bridge elastically bent (i.e., made to be
more linear) and its legs pivoted outwards (e.g., by bending at
elastic hinge regions) so as to be perpendicular to the bridge, and
FIG. 19 is a schematic view showing how the elastically bent staple
of FIG. 18 will have its legs "kick inward" when the strain on the
staple is removed;
[0037] FIGS. 20-22 are schematic views showing another novel staple
formed in accordance with the present invention, wherein the staple
comprises a malleable bridge which is capable of being plastically
bent (i.e., to take a set) and legs which are capable of being
elastically pivoted about elastic hinge regions--FIG. 20 shows the
staple in its unstrained condition, FIG. 21 shows the staple
strained with its malleable bridge plastically bent (i.e., made to
take a set so as to be concave to match the fracture site anatomy)
and its legs pivoted outwards (e.g., by bending at elastic hinge
regions) so as to be perpendicular to the bridge, and FIG. 22 is a
schematic view showing how the elastically bent staple of FIG. 21
will have its legs "kick inward" when the strain on the staple is
removed; and
[0038] FIG. 23 shows how the holes at the hinge region of the
staple may be used by the surgeon to attach sutures for tying down
tissue (e.g., ligaments, tendons, etc.).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Novel Staple Comprising Bridge with Two Elastic Hinge Regions
Incorporating Mounting Holes
[0039] Looking first at FIG. 1, there is shown a novel staple 5
which is able to bring bone fragments into close proximity with
each other, generate a compressive load across the fracture line,
and maintain a compressive load across the fracture line while
healing occurs. Staple 5 can be fully seated against the bone
fragments without needing to be tamped after being released from
the delivery device.
[0040] Novel staple 5 is preferably manufactured from a shape
memory material (e.g., a material capable of exhibiting
superelasticity and/or a temperature-induced shape change). The
shape memory material may comprise a metal alloy (e.g., Nitinol) or
a polymer (e.g., appropriately processed PEEK). Alternatively,
staple 5 may be manufactured from another suitable material, e.g.,
stainless steel, titanium, etc. Staple 5 is designed to reduce
fractures and generate and maintain compression between bone
fragments (e.g., across a fracture line) so as to aid in fracture
healing. Staple 5 comprises an elastic bridge 10 and two elastic
legs 15. Bridge 10 and legs 15 meet at a pair of curved hinge
regions 20 which are also elastic. Hinge regions 20 have holes 25
passing therethrough. Holes 25 may be round or may have other
configurations consistent with the present invention. Legs 15 may
have barbed teeth 30 to help the legs of the staple grip the bone
after implantation into the bone and prevent the legs of the staple
from working their way back out of the bone. In its unrestrained
state, bridge 10 is bowed upwardly in the manner shown in FIG. 1.
In the unrestrained state, legs 15 of staple 5 are elastically
pivoted inwardly at elastic hinge regions 20 with an angle of less
than 90.degree. (relative to bridge 10). By way of example but not
limitation, in one preferred form of the invention, legs 15 extend
at an angle of about 65.degree. to the longitudinal axis of bridge
10 when in their unrestrained state.
[0041] Prior to implantation, bridge 10 of staple 5 can be
reversibly bent (i.e., bent to nearly linear) and legs 15 of staple
5 can be reversibly pivoted at elastic hinge regions 20 (e.g., by
bending at the elastic hinge regions 20) to a position
substantially perpendicular to bridge 10 (FIG. 2) so as to allow
for insertion of the legs of the staple into a prepared fracture
site, with the bridge of the staple spanning across the fracture
line (see below). Note that where staple 5 is formed out of
Nitinol, elastic deformations of up to approximately 8% are
achievable. A delivery device (see below) can be used to
elastically bend bridge 10 and pivot legs 15 at elastic hinge
regions 20 (e.g., by bending at the elastic regions 20), constrain
and hold the staple in its strained state prior to implantation,
and then insert the staple into the prepared fracture site.
[0042] Upon insertion of the strained staple 5 into the prepared
fracture site, the constraint on bridge 10 and legs 15 is removed,
whereupon staple 5 attempts to return to its original un-restrained
state (FIG. 3), thereby generating a compressive load across the
fracture line and maintaining that compressive load across the
fracture line while healing occurs.
[0043] Looking next at FIGS. 4, 4A, 4B, 5, 6, 6A, 6B, 7 and 8,
there is shown a novel delivery device 35 which may be used to
selectively bend bridge 10 and to selectively pivot legs 15 of
staple 5 at elastic hinge regions 20 (e.g., by bending at the
elastic hinge regions 20). Delivery device 35 comprises a body 40
having an internal threaded region 45 (FIG. 6) configured to mate
with threaded screw 50. Threaded screw 50 has a handle 55 mounted
to its proximal end. Advancing threaded screw 50 into body 40
(e.g., by selectively rotating handle 55 so as to selectively
rotate threaded screw 50 such that the threads of threaded screw 50
engage internal threaded region 45) causes the distal end of
threaded screw 50 to push against the proximal end of a plunger 60.
The distal end of plunger 60 engages elastic bridge 10 of staple 5.
When plunger 60 is moved distally (i.e., by moving threaded screw
50 distally by rotating handle 55), the distal end of plunger 60
engages elastic bridge 10 of stable 5 and elastically bends elastic
bridge 10 into a more linear configuration. Staple 5 is releasably
mounted to delivery device 35 by a pair of pins 65 which are
mounted to two arms 70 which are each pivotally mounted to body 40
of delivery device 35 by a pivot pin 75. Pins 65 are received
within holes 25 formed in staple 5. When plunger 60 is moved
distally against elastic bridge 10 of staple 5, the deforming
(i.e., straightening) bridge 10 of staple 5 causes arms 70 of
delivery device 35 to pivot outwardly, with elastic hinge regions
20 of staple 5 bending about pins 65 so as to pivot staple legs 15
outwardly.
[0044] More particularly, and looking now at FIGS. 7 and 8, when
staple 5 is mounted to pins 65 of delivery device 35 (i.e., with
pins 65 being received within holes 25 of staple 5) and handle 55
is rotated so as to advance threaded screw 50 distally, plunger 60
is also advanced distally, whereby to push against elastic bridge
10, causing elastic bridge 10 to bend and become more linear, and
causing arms 70 of delivery device 35 to articulate (i.e., pivot)
outwardly. As this occurs, elastic hinge regions 20 of staple 5
bend about pins 65, causing elastic legs 15 to be pivoted about
elastic hinge regions 20 so as to be oriented generally
perpendicular to elastic bridge 10 (FIG. 8).
[0045] Note that staple 5 is configured so that the force that is
generated as staple 5 reconfigures (i.e., as bridge 10 and legs 15
attempt to return back to their original disposition) is less than
the "tear through" force of the bone receiving legs 15, i.e.,
staple 5 is specifically engineered so as to not "tear through" the
bone tissue when staple 5 attempts to return to its original,
unbiased shape. The compressive forces generated by staple 5 as
staple 5 attempts to reconfigure (i.e., as bridge 10 contracts and
as elastic legs 15 of staple 5 attempt to pivot inboard toward one
another about elastic hinge regions 20) can be controlled by
modulating the material properties of staple 5 and/or the geometry
of staple 5.
[0046] By way of example but not limitation, the percentage of cold
work in the shape memory material forming staple 5 affects the
compressive force that is generated by the reconfiguring staple 5.
As the percentage of cold work increases, the compression force
that is generated decreases. In one preferred form of the present
invention, staple 5 has between about 15% and about 55% cold work
in order to control the recovery force (i.e., the compressive force
generated by bridge 10 and legs 15 as staple 5 reconfigures) of
staple 5; however, if desired, other degrees of cold work may be
used, and/or the material comprising staple 5 may not be cold
worked at all.
[0047] By way of further example but not limitation, another
material property that affects the compression force generated by
staple 5 as the staple reconfigures is the temperature differential
between the body that staple 5 will be implanted into (assumed to
be approximately 37.degree. C., which is the temperature of a human
body) and the austenite finish temperature of the shape memory
material forming staple 5. A smaller temperature differential
between the two will result in staple 5 generating a smaller
compressive load as staple 5 reconfigures; conversely, a larger
temperature differential between the two will result in staple 5
generating a larger compressive load as staple 5 reconfigures. The
shape memory material that staple 5 is made out of should,
preferably, have an austenite finish temperature of greater than
about -10.degree. C., resulting in a temperature differential of
about 47.degree. C. when the staple is implanted (assuming that the
staple is implanted in a human body).
[0048] By way of further example but not limitation, staple
geometry also affects the compression forces generated as staple 5
reconfigures. More particularly, the cross-sectional areas of
elastic bridge 10, elastic hinges 20 and elastic legs 15 affect the
compression forces generated by the reconfiguring staple 5. As the
cross-sectional areas increase, the compression forces that the
reconfiguring staple 5 generates also increase.
[0049] Elastic legs 15 of staple 5 are critical for transmitting
the compression force to the bone without "tearing through" the
bone. The height, width, and length of the staple legs, and the
geometry of the staple legs, are all significant factors relating
to the staple's ability to not "tear through" the bone. Elastic
legs 15 having greater surface area are better able to distribute
the compression force and thus resist "tearing through" the
bone.
[0050] FIG. 9 shows how staple 5 may be used to reduce a fracture
and generate and maintain compression between bone fragments 80 and
85.
[0051] More particularly, the fracture 90 which is to be fused is
first re-approximated and reduced. A drill guide (not shown) of the
sort well known in the art is used to drill two holes 95 the
correct distance apart to accommodate the legs 15 of staple 5.
Staple 5 is mounted to pins 65 of delivery device 35, and delivery
device 35 is used to bend bridge 10 and straighten legs 15 of
staple 5 in the manner discussed above (i.e., by turning handle 55
to advance plunger 60 which is used to bend bridge 10 and pivot
legs 15 at elastic hinge regions 20). While still mounted to pins
65 of delivery device 35, legs 15 of staple 5 are placed into the
pre-drilled holes 95. Staple 5 is then released from pins 65 of
delivery device 35, i.e., by turning handle 55 in the opposite
(e.g., counter-clockwise) direction and sliding staple 5 off of
pins 65. This allows the bent bridge 10 and pivoted legs 15 of
staple 5 to attempt to return (reconfigure) to their un-bent
configuration, thereby applying compression across fracture 90.
[0052] Note that in the preferred form of the invention, staple 105
is designed to generate and maintain compression between both the
cortical bone and the cancellous bone of the bone fragments so as
to promote effective healing. In this respect note also that, while
bridge 10, elastic hinges 20 and the proximal (i.e., bridge-side)
portions of legs 15 typically engage cortical bone, the pivoting
nature of the reconfiguring distal portions of legs 15 will help
apply enhanced compressive forces to the cancellous bone (i.e., the
interior bone) of the bone fragments.
[0053] Significantly, it should be appreciated that since staple 5
is mounted to delivery device 35 via pins 65 being inserted into
holes 25, staple 5 can be fully inserted into pre-drilled holes 95
with bridge 10 in direct contact with bone fragments 80 and 85.
Tamping is not needed in order to fully seat staple 5 (FIG.
10).
[0054] It should also be appreciated that, if desired, staple 5 can
be used to attach soft tissue to bone (e.g., to attach a rotator
cuff to bone).
[0055] In some circumstances it can be desirable to modify delivery
device 35 so as to ensure that legs 15 cannot be pivoted at hinge
regions 20 beyond 90 degrees (relative to the longitudinal axis of
bridge 10) when legs 15 of staple 5 are pivoted outboard. In other
circumstances, it may be desirable for delivery device 35 to allow
legs 15 of staple 5 to be pivoted outboard less than, or greater
than, 90 degrees to allow insertion into slightly mispositioned (or
angled) drill holes 95.
[0056] It should be appreciated that following implantation, if
desired, delivery device 35 can also be used to remove staple 5
from the bone. More particularly, delivery device 35 can be used to
re-engage staple 5 at the holes 25 (i.e., by inserting pins 65 of
delivery device 35 into holes 25 of staple 5) in the hinge regions
20 of staple 5. Turning handle 55 (e.g., clockwise) causes plunger
60 to bend staple bridge 10 and to reconfigure staple 5 such that
bridge 10 is substantially perpendicular to staple legs 15. Staple
5 can then be removed from the bone by pulling the staple out
perpendicular to the bone.
[0057] Additionally, staple delivery device 35 allows the surgeon
to "sense" how much compression staple 5 will exert on the bone
when it is released from delivery device 35 and attempts to
reconfigure. More particularly, as the surgeon turns handle 55 to
straighten bridge 10 and open staple legs 15 (e.g., by turning
handle 55 clockwise), handle 55 requires greater levels of torque
as staple 5 is opened (i.e, as bridge 10 is pushed down and legs 15
are pivoted outboard), thereby providing a degree of tactile
feedback to the surgeon. The torque that the surgeon applies to
handle 55 is proportional to the compression that staple 5 will
exert on the bone as the staple reconfigures.
[0058] Thus delivery device 35 also allows the surgeon to ascertain
and control how much compression staple 5 will exert when the
staple is released from delivery device 35. The greater the degree
to which bridge 10 is straightened and legs 15 of staple 5 are
opened (i.e., pivoted outboard), the more compressive force staple
5 will exert on the bone when it is released from delivery device
35.
[0059] Additionally, delivery device 35 also allows the surgeon to
control the rate at which staple 5 loads the bone as the staple is
removed from delivery device 35. More particularly, turning handle
55 of delivery device 35 counterclockwise releases the downward
(i.e., distal) force that plunger 60 exerts on bridge 10 of staple
5. This allows staple 5 to attempt to recover (i.e., reconfigure)
to its original shape and apply compression across the fracture
site. It may be desirable to allow the surgeon to be able to
control this "release rate" so that the bone is not damaged as
staple 5 reconfigures and so that staple 5 remains in the desired
location.
[0060] In one preferred form of the invention, staple 5 and
delivery device 35 are provided in the form of a sterilized kit.
Staple 5 may be "pre-loaded" (i.e, mounted) onto delivery device 35
(i.e., with pins 65 of delivery device 35 extending through holes
25 of staple 5). Staple 5 may be mounted on delivery device 35 in
an unconstrained or a constrained state. The kit may include
additional instruments to aid in the implantation of the staple
(e.g., k-wire, drill bit, staple size guide, etc.).
Example
[0061] The compressive force generated by staples of the present
invention formed out of Nitinol with greater than 20% cold work are
able to generate 50 to 100 Newtons of force depending on the staple
dimensions. This is more than twice the compression force able to
be generated by conventional staples of a similar size.
Alternative Configurations of Novel Staple Formed in Accordance
with the Present Invention
[0062] Looking now at FIGS. 11-19 it should be appreciated that
staple bridge 10 may be formed so as to have a different
configuration. By way of example but not limitation, it may be
beneficial for staple bridge 10 to have a concave geometry (FIGS.
11-13), such that when bridge 10 of staple 5 is reversibly bent
(i.e., so that legs 15 are pivoted so that they are parallel to
each other), bridge 10 can bend downwardly, i.e., so as to become
more concave (FIG. 12). Upon insertion of the strained staple 5
across the prepared fracture site, the constraint on bridge 10 and
hinges 20 is removed, whereupon staple 5 attempts to return (i.e.,
reconfigure) to its original un-restrained state (FIG. 13), thereby
generating a compressive load across the fracture line and
maintaining that compressive load across the fracture line while
healing occurs. By way of example but not limitation, it may be
beneficial to provide a staple 5 having a concave bridge 10 for the
treatment of fractures where the anatomy is "hour-glass" shaped
(e.g., in an Akin Osteotomy).
[0063] It may also be desirable to provide a staple 5 having a
bridge 10 formed with a sloped geometry (FIG. 14). In this form of
the invention, legs 15 can be elastically pivoted so as to be
parallel to one another (FIG. 15). Upon insertion of the strained
staple 5 into the prepared fracture site, the constraint on bridge
10 and hinges 20 is removed, whereupon staple 5 attempts to return
to its original un-restrained state (FIG. 16), thereby generating a
compressive load and maintaining that compressive load while
healing occurs. It may be desirable to provide staple 5 having this
configuration for the treatment of fractures where the anatomy is
non-linear (e.g., at the metaphyseal flares).
[0064] It may also be desirable to provide staple 5 with bridge 10
having a stepped geometry (FIG. 17). In this form of the invention,
when staple 5 is reversibly strained (i.e., so that legs 15 are
pivoted outboard so as to be parallel to each other), bridge
segments 10a and 10b are parallel to each other (FIG. 18). Upon
insertion of the strained staple 5 into the prepared fracture site,
the constraint on bridge 10 and hinges 20 is removed, whereupon
staple 5 attempts to return (i.e., reconfigure) to its original
un-restrained state (FIG. 19), thereby generating a compressive
load across the fracture line and maintaining that compressive load
across the fracture line while healing occurs. It may be desirable
to provide a staple 5 having this configuration for the treatment
of fractures where the anatomy is uneven (i.e., sliding calcaneal
osteotomies, calcaneocuboid fusions, Lapidus procedures, etc.).
Novel Staple Having a Malleable Bridge which is Plastically
Deformable to Take a Set
[0065] It may also be desirable to provide a staple 5 having a
malleable bridge 10 which is plastically deformable so as to be
able to take a set (FIG. 20). This allows the surgeon to shape
staple bridge 10 in order to conform to the anatomy of the patient.
With this form of the invention, delivery device 35 can be used to
deform/shape staple bridge 10. When a staple of this configuration
has a force applied to its bridge 10 so that staple legs 15 are
pivoted so as to be parallel to each other, malleable bridge 10 is
plastically deformed so as to take a set (FIG. 21). The more staple
legs 15 are opened (i.e., pivoted outboard), the more staple bridge
10 is plastically deformed. Upon insertion of the strained staple 5
into the prepared fracture site, elastic hinges 20 attempt to
return staple legs 15 to their original un-restrained state while
staple bridge 10 remains deformed (FIG. 22), thereby generating a
compressive load and maintaining that compressive load across the
fracture line while healing occurs. A staple of this configuration
may be beneficial for the treatment of fractures where the anatomy
is uneven (e.g., in an Akin Osteotomy).
Additional Use for Staple Mounting Holes
[0066] While holes 25 are primarily used for releasably mounting
staple 5 to delivery device 35 (i.e., via pins 65), holes 25 also
may be used after implantation to aid the surgeon with tying
ligaments and/or tendons directly down to the bone (FIG. 23).
Typically, a surgeon would use a suture anchor, bone tunnel or
other method/device known in the art to re-secure a ligament and/or
tendon to the bone. It should be appreciated that the staple of the
present invention provides the surgeon with holes 25 which may be
used to tie ligaments and/or tendons directly to the bone. This
allows the surgeon to avoid having to use an additional implant or
perform an additional procedure to achieve the same outcome.
Additional Applications
[0067] In the foregoing disclosure, novel staple 5 and novel
delivery device 35 are discussed in the context of rejoining a
broken bone. However, it should be appreciated that novel staple 5
and novel delivery device 35 may be used to promote joinder of
substantially any two (or more) bone segments, e.g., they may be
used to reduce openings and maintain compression between bone
segments in osteotomies, or they may be used for inducing fusion
across the bones of a joint in an arthrodesis, etc.
Modifications of the Preferred Embodiments
[0068] It should be understood that many additional changes in the
details, materials, steps and arrangements of parts, which have
been herein described and illustrated in order to explain the
nature of the present invention, may be made by those skilled in
the art while still remaining within the principles and scope of
the invention.
* * * * *