U.S. patent application number 15/901632 was filed with the patent office on 2019-08-22 for knitted tissue scaffolds.
The applicant listed for this patent is Ethicon LLC. Invention is credited to Victoria Dalessandro, Jason L. Harris, Frederick E. Shelton, IV, Michael J. Vendely.
Application Number | 20190254667 15/901632 |
Document ID | / |
Family ID | 67982210 |
Filed Date | 2019-08-22 |
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United States Patent
Application |
20190254667 |
Kind Code |
A1 |
Vendely; Michael J. ; et
al. |
August 22, 2019 |
KNITTED TISSUE SCAFFOLDS
Abstract
Staple cartridge assemblies for use with surgical stapling
instruments and methods for manufacturing the same are provided.
Scaffolds for use with a surgical staple cartridge and methods for
manufacturing the same are also provided.
Inventors: |
Vendely; Michael J.;
(Lebanon, OH) ; Dalessandro; Victoria; (Scotch
Plains, NJ) ; Harris; Jason L.; (Lebanon, OH)
; Shelton, IV; Frederick E.; (Hillsboro, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ethicon LLC |
Guaynabo |
PR |
US |
|
|
Family ID: |
67982210 |
Appl. No.: |
15/901632 |
Filed: |
February 21, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D04B 21/20 20130101;
D04B 21/16 20130101; A61B 2017/07257 20130101; A61B 2017/00367
20130101; A61B 2017/00862 20130101; A61L 31/148 20130101; D10B
2331/041 20130101; B29C 70/24 20130101; A61B 2017/00964 20130101;
A61L 31/14 20130101; D10B 2331/04 20130101; A61B 2017/07271
20130101; A61B 2017/07278 20130101; D10B 2509/00 20130101; A61B
2017/00004 20130101; A61L 31/041 20130101; D10B 2403/021 20130101;
A61B 17/0644 20130101; A61B 17/07292 20130101; A61B 2017/00526
20130101; A61B 2017/07285 20130101; A61B 17/115 20130101; D10B
2401/024 20130101; A61B 17/07207 20130101; D04B 23/10 20130101 |
International
Class: |
A61B 17/072 20060101
A61B017/072; A61B 17/064 20060101 A61B017/064; A61L 31/14 20060101
A61L031/14; A61L 31/04 20060101 A61L031/04; D04B 23/10 20060101
D04B023/10; D04B 21/16 20060101 D04B021/16; D04B 21/20 20060101
D04B021/20 |
Claims
1. A staple cartridge assembly for use with a surgical stapling
instrument, comprising: a staple cartridge having a plurality of
staples and a cartridge deck; and a knitted elastically deformable,
bioabsorbable scaffold attached to the cartridge deck and formed of
at least three distinct zones, each having a different
functionality, wherein the staples are deployable through the
scaffold into tissue captured against the scaffold, and wherein the
scaffold comprises: a first knitted zone that is configured to
promote tissue ingrowth, wherein the first knitted zone includes
first fibers made of a first bioabsorbable polymer and second
fibers made of a second bioabsorbable polymer, wherein each first
fiber has a fiber diameter that is less than a fiber diameter of
each second fiber; a second knitted zone that is configured to be
conformable so as to attach to the cartridge deck and includes the
first and second fibers of the first knitted zone; and a spacer
zone formed of the second fibers, wherein the spacer zone is
disposed between the first and second knitted zones and is
configured to support the first and second knitted zones, wherein
the second fibers are non-fixedly and slidably interconnected to
the first fibers of the first and second knitted zones, wherein
openings are present in the first and second knitted zones and
voids are present in the spacer zone, with the voids being larger
than the openings.
2. The staple cartridge assembly of claim 1, wherein the fiber
diameters of the first fibers are from about 1/5 to 1/20 of the
fiber diameters of the second fibers.
3. The staple cartridge assembly of claim 1, wherein the fiber
diameters of the first fibers are about 1/10 of the fiber diameters
of the second fibers.
4. The staple cartridge assembly of claim 1, wherein the second
fibers extend from the first knitted zone to the second knitted
zone such that the second fibers extend across the spacer zone,
wherein at least a portion of the second fibers within the spacer
zone are oriented substantially perpendicular to the first fibers
of the first and second knitted zones.
5. The staple cartridge assembly of claim 1, wherein the first type
of fibers are formed of at least one of poly-L-lactic acid, a
copolymer of glycolide and L-lactide, a copolymer of glycolic acid
and lactic acid, poly(lactic-co-glycolic acid), poly(lactic acid),
polyglycolide, and a copolymer of glycolide, caprolactone,
trimethylene carbonate, and lactide.
6. The staple cartridge assembly of claim 1, wherein the second
type of fibers are formed of at least one of polydioxanone, a
copolymer of polydioxanone and polyglycolide, a copolymer of
lactide and polycaprolactone), a copolymer of glycolide, dioxanone,
and trimethylene carbonate, poly(trimethylene carbonate),
polyhydroxyalkanoate, and polyglyconate.
7. The staple cartridge assembly of claim 1, wherein the scaffold
is configured to apply a stress of at least about 3 g/mm.sup.2 to
the captured tissue for at least 3 days when the scaffold is in a
tissue deployed state.
8. A staple cartridge assembly for use with a surgical stapling
instrument, comprising: a staple cartridge having a plurality of
staples and a cartridge deck; and a knitted elastically deformable,
bioabsorbable scaffold attached to the cartridge deck and formed of
at least three distinct zones, each having a different
functionality, wherein the staples are deployable through the
scaffold into tissue captured against the scaffold, and wherein the
scaffold comprises: a first zone having a knitted configuration and
that is configured to promote tissue ingrowth, wherein the first
zone includes first fibers made of a first bioabsorbable polymer;
and a second zone that is formed of second fibers made of a second
bioabsorbable polymer and is configured to vertically support the
first zone, wherein the second fibers are non-fixedly and slidably
interconnected to the first fibers of the first zone such that the
second fibers are substantially vertically oriented within the
second zone, wherein each first fiber has a fiber diameter that is
less than a fiber diameter of each second fiber, and wherein
openings are present in the first zone and voids are present in the
second zone, with the voids being larger than the openings.
9. The staple cartridge assembly of claim 8, wherein the scaffold
further comprises a third zone having a knitted configuration and
that is configured to be conformable so as to attach to the
cartridge deck, the third zone including the first fibers, and
wherein the second zone is located between the first and third
zones.
10. The staple cartridge assembly of claim 8, wherein the second
fibers are non-fixedly and slidably interconnected to the first
fibers of the third zone, and wherein the second fibers extend from
the first zone to the third zone such that at least a portion of
the second fibers are vertically oriented within the second
zone.
11. The staple cartridge assembly of claim 10, wherein the scaffold
is configured to apply a stress of at least about 3 g/mm.sup.2 to
the captured tissue for at least 3 days when the scaffold is in a
tissue deployed state.
12. The staple cartridge assembly of claim 8, wherein the fiber
diameters of the first fibers are from about 1/5 to 1/20 of the
fiber diameters of the second fibers.
13. The staple cartridge assembly of claim 8, wherein the fiber
diameters of the first fibers are about 1/10 of the fiber diameters
of the second fibers.
14. The staple cartridge assembly of claim 8, wherein the first
type of fibers are formed of at least one of poly-L-lactic acid, a
copolymer of glycolide and L-lactide, a copolymer of glycolic acid
and lactic acid, poly(lactic-co-glycolic acid), poly(lactic acid),
polyglycolide, and a copolymer of glycolide, caprolactone,
trimethylene carbonate, and lactide.
15. The staple cartridge assembly of claim 8, wherein the second
type of fibers are formed of at least one of polydioxanone, a
copolymer of polydioxanone and polyglycolide, a copolymer of
lactide and polycaprolactone), a copolymer of glycolide, dioxanone,
and trimethylene carbonate, poly(trimethylene carbonate),
polyhydroxyalkanoate, and polyglyconate.
16. A scaffold for use with a surgical staple cartridge,
comprising: a first knitted zone that is configured to promote
tissue ingrowth, wherein the first knitted zone includes first
fibers made of a first bioabsorbable polymer and second fibers made
of a second bioabsorbable polymer, wherein each first fiber has a
fiber diameter that is less than a fiber diameter of each second
fiber; a second knitted zone that is configured to be conformable
so as to attach to a cartridge deck and includes the first and
second fibers of the first knitted zone; and a spacer zone formed
of the second fibers, wherein the spacer zone is disposed between
the first and second knitted zones and is configured to support the
first and second knitted zones, wherein the second fibers are
non-fixedly and slidably interconnected to the first fibers of the
first and second knitted zones, wherein openings are present in the
first and second knitted zones and voids are present in the spacer
zone, with the voids being larger than the openings.
Description
FIELD
[0001] Knitted tissue scaffolds and methods for manufacturing the
same are provided.
BACKGROUND
[0002] Surgical staplers are used in surgical procedures to close
openings in tissue, blood vessels, ducts, shunts, or other objects
or body parts involved in the particular procedure. The openings
can be naturally occurring, such as passageways in blood vessels or
an internal organ like the stomach, or they can be formed by the
surgeon during a surgical procedure, such as by puncturing tissue
or blood vessels to form a bypass or an anastomosis, or by cutting
tissue during a stapling procedure.
[0003] Some surgical staplers require a surgeon to select the
appropriate staples having the appropriate staple height for the
tissue being stapled. For example, a surgeon could select tall
staples for use with thick tissue and short staples for use with
thin tissue. In some instances, however, the tissue being stapled
does not have a consistent thickness and, thus, the staples cannot
achieve the desired fired configuration at each staple site. As a
result, a desirable seal at or near all of the stapled sites cannot
be formed, thereby allowing blood, air, gastrointestinal fluids,
and other fluids to seep through the unsealed sites.
[0004] Further, staples, as well as other objects and materials
that can be implanted in conjunction with procedures like stapling,
generally lack some characteristics of the tissue in which they are
implanted. For example, staples and other objects and materials can
lack the natural flexibility of the tissue in which they are
implanted, and therefore are unable to withstand the varying
intra-tissue pressures at the implantation site. This can lead to
undesirable tissue tearing, and consequently leakage, at or near
the staple site, and/or leakage between the apposed implant and
tissue.
[0005] Accordingly, there remains a need for improved instruments
and methods that address current issues with surgical staplers.
SUMMARY
[0006] Staple cartridge assemblies for use with a surgical stapling
instrument are provided.
[0007] In one exemplary embodiment, the staple cartridge assembly
can include a staple cartridge having a plurality of staples and a
cartridge deck, and a knitted elastically deformable, bioabsorbable
scaffold attached to the cartridge deck and formed of at least
three distinct zones, each having a different functionality, where
the staples are deployable through the scaffold into tissue
captured against the scaffold. The scaffold can include a first
knitted zone that can be configured to promote tissue ingrowth, a
second knitted zone that can be configured to be conformable so as
to attach to the cartridge deck, and a spacer zone that is disposed
between the first and second knitted zones and can be configured to
support the first and second knitted zones, where openings are
present in the first and second knitted zones and voids are present
in the spacer zone, with the voids being larger than the openings.
The first knitted zone can include first fibers made of a first
bioabsorbable polymer and second fibers made of a second
bioabsorbable polymer, where each first fiber has a fiber diameter
that is less than a fiber diameter of each second fiber. The second
knitted zone can include the first and second fibers of the first
knitted zone. The spacer zone can be formed of the second fibers in
which the second fibers are non-fixedly and slidably interconnected
to the first fibers of the first and second knitted zones. In one
aspect, the scaffold can be configured to apply a stress of at
least about 3 g/mm.sup.2 to the captured tissue for at least 3 days
when the scaffold is in a tissue deployed state.
[0008] In some aspects, the fiber diameters of the first fibers can
be from about 1/5 to 1/20 of the fiber diameters of the second
fibers. In other aspects, the fiber diameters of the first fibers
can be about 1/10 of the fiber diameters of the second fibers.
[0009] In one aspect, the second fibers can extend from the first
knitted zone to the second knitted zone such that the second fibers
extend across the spacer zone and at least a portion of the second
fibers within the spacer zone can be oriented substantially
perpendicular to the first fibers of the first and second knitted
zones.
[0010] The first and second type of fibers can be formed of a
variety of materials. In one aspect, the first type of fibers can
be formed of at least one of poly-L-lactic acid, a copolymer of
glycolide and L-lactide, a copolymer of glycolic acid and lactic
acid, poly(lactic-co-glycolic acid), poly(lactic acid),
polyglycolide, and a copolymer of glycolide, caprolactone,
trimethylene carbonate, and lactide. In another aspect, the second
type of fibers can be formed of at least one of polydioxanone, a
copolymer of polydioxanone and polyglycolide, a copolymer of
lactide and polycaprolactone), a copolymer of glycolide, dioxanone,
and trimethylene carbonate, poly(trimethylene carbonate),
polyhydroxyalkanoate, and polyglyconate.
[0011] In another embodiment, a staple cartridge assembly is
provided and can include a staple cartridge having a plurality of
staples and a cartridge deck, and a knitted elastically deformable,
bioabsorbable scaffold attached to the cartridge deck and formed of
at least three distinct zones, each having a different
functionality, where the staples are deployable through the
scaffold into tissue captured against the scaffold. The scaffold
can include a first zone that can have a knitted configuration and
that can be configured to promote tissue ingrowth, where the first
zone includes first fibers made of a first bioabsorbable polymer.
The scaffold can also include a second zone that can be formed of
second fibers made of a second bioabsorbable polymer and that can
be configured to vertically support the first zone, where the
second fibers are non-fixedly and slidably interconnected to the
first fibers of the first zone such that the second fibers are
substantially vertically oriented within the second zone. Each
first fiber can have a fiber diameter that is less than a fiber
diameter of each second fiber, and wherein openings are present in
the first zone and voids are present in the second zone, with the
voids being larger than the openings.
[0012] In some aspects, the scaffold can also include a third zone
that can have a knitted configuration and that can be configured to
be conformable so as to attach to the cartridge deck, where the
third zone can include the first fibers and the second zone can be
located between the first and third zones. In such instances, the
second fibers can be non-fixedly and slidably interconnected to the
first fibers of the third zone in which the second fibers can
extend from the first zone to the third zone such that at least a
portion of the second fibers are vertically oriented within the
second zone. The scaffold can be configured to apply a stress of at
least about 3 g/mm.sup.2 to the captured tissue for at least 3 days
when the scaffold is in a tissue deployed state.
[0013] In some aspects, the fiber diameters of the first fibers can
be from about 1/5 to 1/20 of the fiber diameters of the second
fibers. In other aspects, the fiber diameters of the first fibers
can be about 1/10 of the fiber diameters of the second fibers.
[0014] The first and second type of fibers can be formed of a
variety of materials. In one aspect, the first type of fibers can
be formed of at least one of poly-L-lactic acid, a copolymer of
glycolide and L-lactide, a copolymer of glycolic acid and lactic
acid, poly(lactic-co-glycolic acid), poly(lactic acid),
polyglycolide, and a copolymer of glycolide, caprolactone,
trimethylene carbonate, and lactide. In another aspect, the second
type of fibers can be formed of at least one of polydioxanone, a
copolymer of polydioxanone and polyglycolide, a copolymer of
lactide and polycaprolactone), a copolymer of glycolide, dioxanone,
and trimethylene carbonate, poly(trimethylene carbonate),
polyhydroxyalkanoate, and polyglyconate.
[0015] Scaffolds for use with a surgical staple cartridge are also
provided and can include a first knitted zone that is configured to
promote tissue ingrowth, a second knitted zone that is configured
to be conformable so as to attach to a cartridge deck, and a spacer
zone that is disposed between the first and second knitted zones
and is configured to support the first and second knitted zones,
where openings are present in the first and second knitted zones
and voids are present in the spacer zone, with the voids being
larger than the openings. The first knitted zone can include first
fibers made of a first bioabsorbable polymer and second fibers made
of a second bioabsorbable polymer, where each first fiber has a
fiber diameter that is less than a fiber diameter of each second
fiber. The second knitted zone can include the first and second
fibers of the first knitted zone. The spacer zone can be formed of
the second fibers, where the second fibers can be non-fixedly and
slidably interconnected to the first fibers of the first and second
knitted zones.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office
upon request and payment of the necessary fee.
[0017] This invention will be more fully understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0018] FIG. 1 is a perspective view of one exemplary embodiment of
a conventional surgical stapling and severing instrument;
[0019] FIG. 2 is a perspective view of a wedge sled of a staple
cartridge of the surgical stapling and severing instrument of FIG.
1;
[0020] FIG. 3 is a perspective view of a knife and firing bar
("E-beam") of the surgical stapling and severing instrument of FIG.
1;
[0021] FIG. 4 is a longitudinal cross-sectional view of a surgical
cartridge that can be disposed within the stapling and severing
instrument of FIG. 1;
[0022] FIG. 5 is a top view of a staple in an unfired
(pre-deployed) configuration that can be disposed within the staple
cartridge of the surgical cartridge assembly of FIG. 4;
[0023] FIG. 6 is a longitudinal cross-sectional view of an
exemplary embodiment of a surgical cartridge assembly having a
scaffold attached to a cartridge deck;
[0024] FIG. 7 is a schematic illustrating the scaffold of FIG. 6
when stapled to tissue;
[0025] FIG. 8A is a magnified top view of an exemplary embodiment
of a scaffold that can be attached to the cartridge deck of the
surgical cartridge assembly of FIG. 6;
[0026] FIG. 8B is a magnified cross-sectional view of the scaffold
of FIG. 8A taken at B-B;
[0027] FIG. 8C is another magnified cross-sectional view of the
scaffold of FIG. 8A taken at C-C;
[0028] FIG. 9 is a scanning electron micrograph (SEM) image of the
scaffold in FIGS. 8A-8C at 500 .mu.m scale;
[0029] FIG. 10A is a histopathology image of an implanted scaffold
removed at 60 days as discussed in Example 2.
[0030] FIG. 10B is a magnified view of section 10B in FIG. 10A;
[0031] FIG. 11A is a histopathology image of an implanted scaffold
removed at 90 days as discussed in Example 2;
[0032] FIG. 11B is a magnified view of section 11B in FIG. 11A;
[0033] FIG. 12A is a perspective view of another exemplary
embodiment of a scaffold;
[0034] FIG. 12B is another exemplary embodiment of a staple
cartridge assembly having the scaffold shown in FIG. 12A attached
to a cartridge deck; and
[0035] FIG. 13 is a bottom view of another exemplary embodiment of
a scaffold.
DETAILED DESCRIPTION
[0036] Certain exemplary embodiments will now be described to
provide an overall understanding of the principles of the
structure, function, manufacture, and use of the instruments and
methods disclosed herein. One or more examples of these embodiments
are illustrated in the accompanying drawings. Those skilled in the
art will understand that the instruments, systems, and methods
specifically described herein and illustrated in the accompanying
drawings are non-limiting exemplary embodiments and that the scope
of the present invention is defined solely by the claims. The
features illustrated or described in connection with one exemplary
embodiment may be combined with the features of other embodiments.
Such modifications and variations are intended to be included
within the scope of the present invention.
[0037] Further, in the present disclosure, like-named components of
the embodiments generally have similar features, and thus within a
particular embodiment each feature of each like-named component is
not necessarily fully elaborated upon. Additionally, to the extent
that linear or circular dimensions are used in the description of
the disclosed systems, instruments, and methods, such dimensions
are not intended to limit the types of shapes that can be used in
conjunction with such systems, instruments, and methods. A person
skilled in the art will recognize that an equivalent to such linear
and circular dimensions can easily be determined for any geometric
shape. Sizes and shapes of the systems and instruments, and the
components thereof, can depend at least on the anatomy of the
subject in which the systems and instruments will be used, the size
and shape of components with which the systems and instruments will
be used, and the methods and procedures in which the systems and
instruments will be used.
[0038] It will be appreciated that the terms "proximal" and
"distal" are used herein with reference to a user, such as a
clinician, gripping a handle of an instrument. Other spatial terms
such as "front" and "rear" similarly correspond respectively to
distal and proximal. It will be further appreciated that for
convenience and clarity, spatial terms such as "vertical" and
"horizontal" are used herein with respect to the drawings. However,
surgical instruments are used in many orientations and positions,
and these spatial terms are not intended to be limiting and
absolute.
[0039] Values or ranges may be expressed herein as "about" and/or
from/of "about" one particular value to another particular value.
When such values or ranges are expressed, other embodiments
disclosed include the specific value recited and/or from/of the one
particular value to another particular value. Similarly, when
values are expressed as approximations, by the use of antecedent
"about," it will be understood that here are a number of values
disclosed therein, and that the particular value forms another
embodiment. It will be further understood that there are a number
of values disclosed therein, and that each value is also herein
disclosed as "about" that particular value in addition to the value
itself. In embodiments, "about" can be used to mean, for example,
within 10% of the recited value, within 5% of the recited value or
within 2% of the recited value.
[0040] For purposes of describing and defining the present
teachings, it is noted that unless indicated otherwise, the term
"substantially" is utilized herein to represent the inherent degree
of uncertainty that may be attributed to any quantitative
comparison, value, measurement, or other representation. The term
"substantially" is also utilized herein to represent the degree by
which a quantitative representation may vary from a stated
reference without resulting in a change in the basic function of
the subject matter at issue.
[0041] Surgical staple cartridge assemblies and methods for
manufacturing the same are provided. In general, a staple cartridge
assembly is provided having a staple cartridge that includes a
cartridge deck with a plurality of staples disposed therein. The
staple cartridge assembly also includes a knitted elastically
deformable, bioabsorbable scaffold that is configured to releasably
mate with the cartridge deck and allow the staples to be deployed
therethrough into tissue. The scaffold can be releasably mated to
the cartridge deck such that when a staple is deployed from the
cartridge deck and into tissue, at least a portion of the scaffold
can attach to the tissue captured by the staple. As discussed
herein, the scaffold can be configured to compensate for variations
in tissue properties, such as variations in the tissue thickness,
and/or promote tissue ingrowth when the scaffold is stapled to
tissue. For example, the scaffold can be configured to apply a
stress of at least about 3 g/mm.sup.2 to tissue for at least 3 days
when in a tissue deployed state (e.g., when the scaffold is stapled
to tissue in vivo). An exemplary staple cartridge assembly can
include a variety of features to facilitate application of a
surgical staple, as described herein and illustrated in the
drawings. However, a person skilled in the art will appreciate that
the staple cartridge assembly can include only some of these
features and/or it can include a variety of other features known in
the art. The staple cartridge assemblies described herein are
merely intended to represent certain exemplary embodiments.
Moreover, while the scaffolds are described in connection with
surgical staple cartridge assemblies, the scaffolds can be used in
connection with any type of surgical instrument.
[0042] FIG. 1 illustrates an exemplary surgical stapling and
severing instrument 100 suitable for use with an implantable
adjunct such as, for example, a scaffold. The surgical stapling and
severing instrument 100 can include an anvil 102 which may be
repeatedly opened and closed about its pivotal attachment to an
elongate staple channel 104. A staple applying assembly 106 may
comprise the anvil 102 and the channel 104, wherein the assembly
106 can be proximally attached to an elongate shaft 108 forming an
implement portion 110. When the staple applying assembly 106 is
closed, or at least substantially closed, the implement portion 110
can present a sufficiently small cross-section suitable for
inserting the staple applying assembly 106 through a trocar. While
the instrument 100 is configured to staple and sever tissue,
surgical instruments configured to staple but not sever tissue is
also contemplated herein.
[0043] In various instances, the staple applying assembly 106 is
manipulated by a handle 112 connected to the elongate shaft 108.
The handle 112 can include user controls such as a rotation knob
114 that rotates the elongate shaft 108 and the staple applying
assembly 106 about a longitudinal axis of the elongate shaft 108
and a closure trigger 116, which can pivot in front of a pistol
grip 118 to close the staple applying assembly 106. A closure
release button 120 is outwardly presented on the handle 112 when
the closure trigger 116 is clamped such that the closure release
button 120 can be depressed to unclamp the closure trigger 116 and
open the staple applying assembly 106, for example.
[0044] A firing trigger 122, which can pivot in front of the
closure trigger 116, causes the staple applying assembly 106 to
simultaneously sever and staple tissue clamped therein. In various
instances, multiple firing strokes can be employed using the firing
trigger 122 to reduce the amount of force required to be applied by
the surgeon's hand per stroke. In certain embodiments, the handle
112 can comprise one or more rotatable indicator wheels such as,
for example, rotatable indicator wheel 124 which can indicate the
firing progress. A manual firing release lever 126 can allow the
firing system to be retracted before full firing travel has been
completed, if desired, and, in addition, the firing release lever
126 can allow a surgeon, or other clinician, to retract the firing
system in the event that the firing system binds and/or fails.
[0045] Additional details on the surgical stapling and severing
instrument 100 and other surgical stapling and severing instruments
suitable for use with the present disclosure are described, for
example, in U.S. Pat. No. 9,332,984 and in U.S. Patent Application
Publication No. 2009/0090763, the disclosures of which are
incorporated herein by reference in their entirety. Further, the
surgical stapling and severing instrument need not include a
handle, but instead a housing that is configured to couple to a
surgical robot, for example, as described in U.S. patent
application Ser. No. 15/689,198, filed on Aug. 29, 2017 to
Frederick E. Shelton et al., the disclosure of which is
incorporated herein by reference in its entirety.
[0046] With reference to FIGS. 2 and 3, a firing assembly such as,
for example, firing assembly 228 can be utilized with a surgical
stapling and severing instrument, such as instrument 100 in FIG. 1,
to advance a wedge sled 230 which comprises a plurality of wedges
232 configured to deploy staples from a staple applying assembly,
like staple applying assembly 106 in FIG. 1 into tissue captured
between an anvil, like anvil 102 in FIG. 1 and an elongate staple
channel, like channel 104 in FIG. 1. Furthermore, an E-beam 233 at
a distal portion of the firing assembly 228 may fire the staples
from the staple applying assembly as well as position the anvil
relative to the elongate staple channel during firing. The E-beam
233 includes a pair of top pins 234, a pair of middle pins 236
which may follow portion 238 of the wedge sled 230, and a bottom
pin or foot 240, as well as a sharp cutting edge 242, which can be
configured to sever the captured tissue as the firing assembly 228
is advanced distally. In addition, integrally formed and proximally
projecting top guide 244 and middle guide 246 bracketing each
vertical end of the cutting edge 242 may further define a tissue
staging area 248 assisting in guiding tissue to the sharp cutting
edge 242 prior to being severed. The middle guide 246 may also
serve to engage and fire the staple applying assembly by abutting a
stepped central member 250 of the wedge sled 230 that effects
staple formation by the staple applying assembly.
[0047] Referring to FIG. 4, a staple cartridge 400 can be utilized
with a surgical stapling and severing instrument, like surgical
stapling and severing instrument 100 in FIG. 1, and can include a
cartridge deck 402 and a plurality of staple cavities 404. A staple
406, for example, can be removably positioned in each staple cavity
404. The staple 406 in a unfired (pre-deployed) configuration is
shown in more detail in FIG. 5. The staple cartridge 400 can also
include a longitudinal channel that can be configured to receive a
firing and/or cutting member, e.g., an E-beam, like E-beam 233 in
FIG. 3.
[0048] Each staple 406 can comprise a crown (base) 406c and one or
more legs 406.sub.L extending from the crown 406c. Prior to the
staples 406 being deployed, the crowns 406c of the staples 406 can
be supported by staple drivers 408 positioned within the staple
cartridge 400 and, concurrently, the legs 406.sub.L of the staples
406 can be at least partially contained within the staple cavities
404. Further, the staple legs 406.sub.L of the staples 406 can
extend beyond the tissue-contacting surface 410 of the staple
cartridge 400 when the staples 406 are in their unfired positions.
In certain instances, as shown in FIG. 5, the tips of the staple
legs 406 can comprise sharp tips which can incise and penetrate
tissue.
[0049] The staples 406 can be deployed between an unfired position
and a fired position such that the legs 406.sub.L move through the
staple cavities 404, penetrate tissue positioned between an anvil,
like anvil 102 in FIG. 1, and the staple cartridge 400, and contact
the anvil. As the legs 406.sub.L are deformed against the anvil,
the legs 406.sub.L of each staple 406 can capture a portion of the
tissue within each staple 406 and apply a compressive force to the
tissue. Further, the legs 406.sub.L of each staple 406 can be
deformed downwardly toward the crown 406c of the staple 406 to form
a staple entrapment area in which the tissue can be captured
therein. In various instances, the staple entrapment area can be
defined between the inner surfaces of the deformed legs and the
inner surface of the crown of the staple. The size of the
entrapment area for a staple can depend on several factors such as
the length of the legs, the diameter of the legs, the width of the
crown, and/or the extent in which the legs are deformed, for
example.
[0050] In use, an anvil, like anvil 102 in FIG. 1, can be moved
into a closed position by depressing a closure trigger, like
closure trigger 116 in FIG. 1, to advance an E-beam, like E-beam
233 in FIG. 3. The anvil can position tissue against a
tissue-contacting surface 410 of the staple cartridge 400. Once the
anvil has been suitably positioned, the staples 406 can be
deployed.
[0051] To deploy staples 406, as discussed above, a staple-firing
sled, like sled 230 in FIG. 2, can be moved from a proximal end
400p toward a distal end 400d of the staple cartridge 400. As a
firing assembly, like firing assembly 228 in FIG. 3, is advanced,
the sled can contact the staple drivers 408 and lift the staple
drivers 408 upwardly within the staple cavities 404. In at least
one example, the sled and the staple drivers 408 can each include
one or more ramps, or inclined surfaces, which can co-operate to
move the staple drivers 408 upwardly from their unfired positions.
As the staple drivers 408 are lifted upwardly within their
respective staple cavities 404, the staple drivers 408 can lift the
staples 406 upwardly such that the staples 406 can emerge from
their staple cavities 404 and penetrate into tissue. In various
instances, the sled can move several staples upwardly at the same
time as part of a firing sequence.
[0052] A person skilled in the art will appreciate that, while
scaffolds are shown and described below, the scaffolds disclosed
herein can be used with other surgical instruments, and need not be
coupled to a staple cartridge as described.
[0053] As discussed above, with some surgical staplers, a surgeon
is often required to select the appropriate staples having the
appropriate staple height for the tissue that is to be stapled. For
example, a surgeon could select tall staples for use with thick
tissue and short staples for use with thin tissue. In some
instances, however, the tissue being stapled does not have a
consistent thickness and, thus, the staples cannot achieve the
desired fired configuration for every section of the stapled tissue
(e.g., thick and thin tissue sections). The inconsistent thickness
of tissue can also lead to undesirable leakage and/or tearing of
tissue at the staple site when staples with the same or
substantially height are used, particularly when the staple site is
exposed to intra-tissue pressures at the staple site and/or along
the staple line.
[0054] Accordingly, various embodiments of scaffolds are provided
that can be configured to compensate for varying thickness of
tissue that is captured within fired (deployed) staples to avoid
the need to take into account staple height when stapling tissue
during surgery. That is, the scaffolds described herein can allow a
set of staples with the same or similar heights to be used in
stapling tissue of varying thickness (i.e., from thin to thick
tissue) while also, in combination with the scaffold, provide
adequate tissue compression within and between fired staples. Thus,
the scaffolds described herein can maintain suitable compression
against, thin or thick tissue stapled thereto to thereby minimize
leakage and/or tearing of tissue at the staple sites.
[0055] Alternatively or in addition, the scaffold can be configured
to promote tissue ingrowth. In various instances, it is desirable
to promote the ingrowth of tissue into an implantable scaffold, to
promote the healing of the treated tissue (e.g. stapled and/or
incised tissue) and/or to accelerate the patient's recovery. More
specifically, the ingrowth of tissue into an implantable scaffold
may reduce the incidence, extent, and/or duration of inflammation
at the surgical site. Tissue ingrowth into and/or around the
implantable scaffold may manage the spread of infections at the
surgical site, for example. The ingrowth of blood vessels,
especially white blood cells, for example, into and/or around the
implantable scaffold may fight infections in and/or around the
implantable scaffold and the adjacent tissue. Tissue ingrowth may
also encourage the acceptance of foreign matter (e.g., the
implantable scaffold and the staples) by the patient's body and may
reduce the likelihood of the patient's body rejecting the foreign
matter. Rejection of foreign matter may cause infection and/or
inflammation at the surgical site.
[0056] In general, the scaffolds provided herein are designed and
positioned atop a staple cartridge, like staple cartridge 400 in
FIG. 4, such that when the staples are fired (deployed) from the
cartridge deck of the staple cartridge, the staples penetrate
through the scaffold and into tissue. As the legs of the staple are
deformed against the anvil that is positioned opposite the staple
cartridge assembly, the deformed legs capture a portion of the
scaffold and a portion of the tissue within each staple. That is,
when the staple is fired into tissue, at least a portion of the
scaffold becomes positioned between the tissue and the fired
staple. While the scaffolds described herein are configured to be
attached to a staple cartridge of a staple cartridge assembly, it
is also contemplated herein that the scaffolds can be configured to
mate with other instrument components, such as a jaw of a surgical
stapler.
[0057] FIG. 6 illustrates an exemplary embodiment of a staple
cartridge assembly 600 that includes a staple cartridge 602 and a
scaffold 604. Aside from the differences described in detail below,
the staple cartridge 602 can be similar to staple cartridge 400
(FIG. 4) and is therefore not described in detail herein. As shown,
the scaffold 604 is positioned against the staple cartridge 602.
The staple cartridge can include a cartridge deck 606 and a
plurality of staples 608, like staples 406 shown in FIGS. 4 and 5.
The staples 608 can be any suitable unformed (pre-deployed) height.
For example, the staples 608 can have an unformed height between
about 2 mm to 4.8 mm. Prior to deployment, the crowns of the
staples 608 can be supported by staple drivers 610.
[0058] In the illustrated embodiment, the scaffold 604 can be mated
to an outer surface 612, for example a tissue-contacting surface,
of the cartridge deck 606. The outer surface 612 of the cartridge
deck 606 can include one or more attachment features. The one or
more attachments features can be configured to engage the scaffold
604 to avoid undesirable movements of the scaffold 604 relative to
the cartridge deck 606 and/or premature release of the scaffold 604
from the cartridge deck 606. Exemplary attachment features can be
found in U.S. Patent Publication No. 2016/0106427, which is
incorporated by reference herein in its entirety.
[0059] The scaffold 604 is elastically deformable to permit the
scaffold to compress to varying heights to thereby compensate for
different tissue thickness that are captured within a deployed
staple. The scaffold 604 has an uncompressed (undeformed), or
pre-deployed, height and is configured to deform to one of a
plurality of compressed (deformed), or deployed, heights. For
example, the scaffold 604 can have an uncompressed height which is
greater than the fired height of the staples 608 (e.g., the height
(H) of the fired staple 608a in FIG. 7). In one embodiment, the
uncompressed height of the scaffold 604 can be about 10% taller,
about 20% taller, about 30% taller, about 40% taller, about 50%
taller, about 60% taller, about 70% taller, about 80% taller, about
90% taller, or about 100% taller than the fired height of the
staples 608. In certain embodiments, the uncompressed height of the
scaffold 604 can be over 100% taller than the fired height of the
staples 608, for example.
[0060] The scaffold 604 can be releasably mated to the outer
surface 612 of the cartridge deck 606. As shown in FIG. 7, when a
staple is fired, tissue (T) and a portion of the scaffold 604 is
captured by the fired (formed) staple 608a. The fired staple 608a
defines the entrapment area therein, as discussed above, for
accommodating the captured scaffold 604 and tissue (T). The
entrapment area defined by the fired staple 608a is limited, at
least in part, by a height (H) of the fired staple 608. For
example, the height of a fired staple 608a can be about 0.130
inches or less. In some embodiments, the height of a fired staple
608a can be from about 0.025 inches to 0.130 inches. In some
embodiments, the height of a fired staple 608a can be from about
0.030 inches to 0.100 inches.
[0061] As described above, the scaffold 604 can be compressed
within a plurality of fired staples whether the thickness of the
tissue captured within the staples is the same or different within
each staple. In at least one exemplary embodiment, the staples
within a staple line, or row, can be deformed such that the fired
height is about 2.75 mm, for example, where the tissue (T) and the
scaffold 604 can be compressed within this height. In certain
instances, the tissue (T) can have a compressed height of about 1.0
mm and the scaffold 604 can have a compressed height of about 1.75
mm. In certain instances, the tissue (T) can have a compressed
height of about 1.50 mm and the scaffold 604 can have a compressed
height of about 1.25 mm. In certain instances, the tissue (T) can
have a compressed height of about 1.75 mm and the scaffold 604 can
have a compressed height of about 1.00 mm. In certain instances,
the tissue (T) can have a compressed height of about 2.00 mm and
the scaffold 604 can have a compressed height of about 0.75 mm. In
certain instances, the tissue (T) can have a compressed height of
about 2.25 mm and the scaffold 604 can have a compressed height of
about 0.50 mm. Accordingly, the sum of the compressed heights of
the captured tissue (T) and scaffold 604 can be equal, or at least
substantially equal, to the height (H) of the fired staple
608a.
[0062] As discussed in more detail below, the structure of the
scaffold can be configured such that when the scaffold and tissue
are captured within the fired staple, the scaffold can apply a
stress that can withstand the pressure of circulating blood through
tissue. High blood pressure is typically considered 210 mmHg, and
therefore it would be desirable for the scaffold to apply a stress
to the tissue that is equal to or greater than 210 mmHg (e.g., 3
g/mm.sup.2) for a predetermined time period (e.g., 3 days). As
such, in certain embodiments, the scaffold can be configured to
apply a stress of at least about 3 g/mm.sup.2 to the captured
tissue for at least 3 days. The scaffold is in a tissue deployed
state when the scaffold is stapled to tissue in vivo. In one
embodiment, the applied stress can be about 3 g/mm.sup.2. In
another embodiment, the applied stress can be greater than 3
g/mm.sup.2. In yet another embodiment, the stress can be at least
about 3 g/mm.sup.2 and applied to the captured tissue for more than
3 days. For example, in one embodiment, the stress can be at least
about 3 g/mm.sup.2 and applied to captured tissue for about 3 days
to 5 days.
[0063] In order to design a scaffold that is configured to apply a
stress of at least about 3 g/mm.sup.2 to the captured tissue for a
predetermined time, one can use the principles of Hooke's law
(F=kD). For example, when the force (stress) to be applied to the
captured tissue is known, one can design a scaffold to have a
stiffness (k). The stiffness can be set by tuning the materials
and/or the geometry of the scaffold (e.g., the type and/or diameter
of the fibers and/or the interconnectivity of the fibers). Further,
one can design the scaffold to have a maximum amount of compression
displacement for a minimum thickness of tissue, e.g., 1 mm, and
therefore the length of displacement D can be the combination of a
minimum thickness of tissue, e.g., 1 mm, plus a thickness of the
tissue when stapled to tissue for a given max staple height, e.g.,
2.75 mm. By way of example, in one embodiment, a scaffold can be
structured to have a height that is greater than a maximum formed
stapled height of 2.75 mm and to compress to a height of 1.75 mm
when stapled to tissue having a minimum thickness of 1 mm.
Therefore, the scaffold can vary in compressibility to maintain a
constant length of displacement D such that the stiffness (k) and
total thickness (D) of captured tissue and scaffold can apply a
stress of 3 g/mm.sup.2 to the captured tissue. It should be noted a
person of ordinary skill in the art will appreciate that the
foregoing formula can be modified to take into account variations
in temperatures, e.g., when the adjunct is brought from room
temperature to body temperature after implantation.
[0064] Additionally, the scaffold can be further developed to
provide a substantially continuous stress to the captured tissue
(e.g., 3 g/mm.sup.2) for a predetermined time (e.g., 3 days). To
achieve this, one would need to take into account the degradation
rate of the materials of the scaffold and the rate of tissue
ingrowth within the scaffold when designing the scaffold. In doing
so, one can design a scaffold such that the stiffness of the
scaffold and/or the total thickness of the captured tissue and
scaffold do not vary in a way that could effect an applied stress
that is less than 3 g/mm.sup.2.
[0065] A scaffold is stapled to tissue under various stapling
conditions (e.g., tissue thickness, height of formed staple,
intra-tissue pressure). Depending on the stapling condition, one
can determine an effective amount of stress that the scaffold needs
to be able to apply to the tissue to prevent tissue tearing and
leakage. For example, in one embodiment, an effective amount of
stress is at least about 3 g/mm.sup.2. In order for the scaffold to
provide an effective amount of stress to the tissue, the scaffold
can be designed to effectively compensate for the various stapling
conditions. As such, the scaffold can be tailored to assume
different compressed heights when stapled to tissue. As there is a
finite range of intra-tissue pressures, tissue thicknesses, and
formed staple heights, one can determine appropriate material
and/or geometric structures for the scaffold that can be effective
in applying a substantially continuous desired stress to the tissue
(e.g., 3 g/mm.sup.2) when stapled thereto for a given amount of
time (e.g., at least 3 days) over a range of stapling conditions.
That is, as described in more detail below, the present scaffolds
are formed of compressible materials and geometrically configured
so as to allow the scaffold to compress to various heights in
predetermined planes when stapled to tissue. Further, this varied
response by the scaffold can also allow the scaffold to maintain
its application of a continuous desired stress to the tissue when
exposed to fluctuations in intra-tissue pressure that can occur
when the scaffold is stapled to tissue (e.g., a spike in blood
pressure).
[0066] The scaffold can have a variety of configurations. For
example, in certain embodiments, the scaffold can include at least
one knitted layer and at least one support layer. As used herein,
"knitted layer" is used synonymously with "knitted zone," and
"support layer" is used synonymously with "spacer zone."
[0067] FIGS. 8A-8C and 9 illustrate an exemplary embodiment of a
scaffold 800 having first and second knitted layers 802, 804 with a
support layer 806 disposed therebetween. In this illustrated
embodiment, the first knitted layer 802 can be configured to be
positioned against tissue and the second knitted layer 804 can be
configured to be positioned against a cartridge deck, like
cartridge deck 606 in FIG. 6.
[0068] As shown, the knitted layers 802, 804 includes fibers 808 of
a first type and fibers 810 of a second type, and the support layer
806 includes the second type of fibers 810. In this way, by having
the scaffold 800 formed of two different fibers 808, 810 the
scaffold can have a variable stiffness profile over time following
implantation. For example, the first type of fibers 808 can
function as a structural component of the knitted layers 802, 804,
and the stiffness profile can be a function of the degradation
profile of the first type of fibers 808 and the interaction between
the first type of fibers 808 with the second type of fibers 810 in
the knitted layers 802, 804.
[0069] Further, the knitted layers 802, 804 can be configured such
that when the scaffold 800 is attached to a cartridge deck, at
least a portion of the first type of fibers 808 are oriented in a
direction that is substantially parallel to the cartridge deck.
While the first and second type of fibers 808, 810 can have a
variety of sizes, in some implementations, the first type of fibers
808 has a fiber diameter that is less than a fiber diameter of the
second type of fibers 810.
[0070] While the fibers 808, 810 of the knitted layers 802, 804 and
of the support layer 806 can either be monofilament or
multifilament, in some implementations, the first type of fibers
808 are multifilament fibers and the second type of fibers 810 are
monofilament fibers, as shown in FIGS. 8A-8C and 9. As used herein,
the term "monofilament fibers" has its own ordinary and customary
meaning and can include fibers formed of a single filament. As used
herein, the term "multifilament fibers" has its own ordinary and
customary meaning and can include fibers formed of two or more
filaments that are associated with one another to form a unitary
structure. In one embodiment, the multifilament fibers are
non-bonded multifilament fibers. As used herein, a "non-bonded
multifilament fiber" has its own ordinary and customary meaning and
can include an assembly of two or more filaments that are in
contact with one another at least one point along their lengths but
are not physically attached to one another. Non-limiting examples
of non-bonded multifilament fibers include yarn (filaments twisted
about one another along their lengths) and tow (filaments not
twisted about one another along their lengths).
[0071] The multifilament fibers can have a variety of
configurations. For example, in some implementations, each
multifilament fiber includes from about 6 to 40 filaments. In one
aspect, each multifilament fiber includes from about 14 to 28
filaments. The increased surface area and voids that exist between
the filaments of the multifilament fibers can facilitate improved
tissue ingrowth within the scaffold (see e.g., Example 2).
[0072] The multifilament fibers can have a variety of sizes. For
example, each multifilament fiber can have an average diameter of
about 0.02 mm to 0.2 mm, of about 0.05 mm to 0.2 mm, or of about
0.15 mm to 0.2 mm. In some implementations, each filament of the
multifilament fibers has a diameter that is less than a fiber
diameter of the monofilament fibers. For example, where the knitted
layers 802, 804 include first type of fibers that are multifilament
fibers and second type of fibers that are monofilament fibers, each
filament of the multifilament fibers can have a diameter that is
about 1/5 to 1/20 the diameter of the monofilament fibers. In
certain embodiments, each filament of the multifilament fibers can
have a diameter that is about 1/10 the diameter of the monofilament
fibers.
[0073] The multifilament fibers can be formed of filaments formed
of the same material or filaments of different materials. For
example, in some implementations, the multifilament fibers can
include first filaments of a first material and second filaments of
a second material. In one embodiment, the second material degrades
at a faster rate than a degradation rate of the first material. In
this way, the degradation of the second material can activate, and
thus encourage accelerated attraction of, macrophages and
accelerate the inflammation phase of healing while not
substantially affecting the variable stiffness profile of the
scaffold over time following implantation. The activation of
macrophages can in turn cause increases in myofibroblast population
and neovascularization. Further, the degradation of the second
material can encourage tissue ingrowth within the scaffold. The
first material, for example, can be at least one of poly-L-lactic
acid, a copolymer of glycolide and L-lactide, a copolymer of
glycolic acid and lactic acid, poly(lactic-co-glycolic acid),
poly(lactic acid), polyglycolide, and a copolymer of glycolide,
caprolactone, trimethylene carbonate, and lactide. Non-limiting
examples of suitable first materials can be formed of polyglactin
910, Lactomer.TM. 9-1, 75:25 or 50:50 lactic acid/glycolic acid,
Polygytone.TM. 6211, or Caprosyn.TM.. The second material, for
example, can be a copolymer of glycolide and L-lactide, such as
Vicryl Rapide.TM..
[0074] While the multifilament fibers can include the second
filaments at various percentage ranges, in some implementations,
the multifilament fibers can each include second filaments at a
range of about 15% to 85% or at a range of about 25% to 45%. The
second filaments can have various fiber diameters. For example, in
some implementations, the second filaments can have a fiber
diameter from about 0.0005 mm to 0.02 mm. In one embodiment, the
second filaments have a fiber diameter of about 0.015 mm.
[0075] The monofilament fibers can have a variety of sizes. For
example, the monofilaments can have a diameter of about 0.2 mm to
0.35 mm. In some implementations, the monofilament fibers can each
have a diameter that is less than an average diameter of the
multifilament fibers. The average diameter (D) of a multifilament
fiber can be calculated using the following formula:
D = 4 W N .rho..pi. ##EQU00001##
[0076] where, [0077] W=weight of multifilament fiber (fiber bundle)
per unit length [0078] N=number of filaments [0079] .rho.=density
of fiber.
[0080] While the first and second type of fibers 808, 810 can have
various glass transition temperatures, in some implementations, the
first type of fibers 808 have a first glass transition temperature
and the second type of fibers 810 have a second glass transition
temperature that is less than the first glass transition
temperature. For example, the first glass transition temperature
can be greater than the second glass transition temperature by at
least about 30 degrees C. In other exemplary embodiments, the first
glass transition temperature can be greater than the second glass
transition temperature by at least about 45 degrees C. A difference
in glass transition of the first and second types of fibers 808,
810 can further facilitate a secure attachment of the scaffold to
the cartridge deck without adversely affecting the structural
integrity of the scaffold.
[0081] As discussed above, a portion of the scaffold is captured
with tissue within the fired staple and therefore it is desirable
that the scaffold be formed of suitable bioabsorbable materials. As
such, the first and second type of fibers 808, 810 can each be
formed of a variety of absorbable materials. Non-limiting examples
of suitable materials for the first type of fibers include at least
one of poly-L-lactic acid, a copolymer of glycolide and L-lactide,
a copolymer of glycolic acid and lactic acid,
poly(lactic-co-glycolic acid), poly(lactic acid), polyglycolide,
and a copolymer of glycolide, caprolactone, trimethylene carbonate,
and lactide. For example, the first type of fibers can be formed of
polyglactin 910, Lactomer.TM. 9-1, 75:25 or 50:50 lactic
acid/glycolic acid, Polygytone.TM. 6211, or Caprosyn.TM..
Non-limiting examples of suitable materials for the second type of
fibers include at least one of polydioxanone, a copolymer of
polydioxanone and polyglycolide, a copolymer of lactide and
polycaprolactone), a copolymer of glycolide, dioxanone, and
trimethylene carbonate, poly(trimethylene carbonate),
polyhydroxyalkanoate, and polyglyconate. For example, the second
type of fibers can be formed of 92:8 polydioxanone/Polyglycolide,
25:75 lactide/polycaprolactone, Glycomer.TM. 631, or Maxon.TM.. In
one embodiment, the first type of fibers is formed of polyglactin
910 and the second type of fibers is formed of polydioxanone.
[0082] In some embodiments, the first type of fibers 808 can be
coated with a bioabsorbable polymeric material. In this way, the
glass transition temperature of the first type of fibers 808 can be
modified, e.g., by either increasing or decreasing the glass
transition compared to the glass transition temperature of the base
material of the first type of fibers, which in certain instances
may be desirable for attaching the scaffold to the cartridge deck.
For example, decreasing the glass transition temperature of the
first type of fibers 808 can provide a more secure attachment of
the scaffold 800 to a cartridge deck, like cartridge deck 606 in
FIG. 6, and/or enhance the conformability of the scaffold 800 to
the cartridge deck and, when cooled, maintain a suitable shape.
Non-limiting examples of suitable coating materials include
polydioxanone or 25:75 lactide/polycaprolactone.
[0083] While the knitted layers 802, 804 can each have various
knitted patterns, in some implementations, like in FIGS. 8A-8C and
9, the knitted layers 802, 804 can each have a Rachel knit pattern
(e.g., as described in Example 1 below). A person skilled in the
art will appreciate that the knitted layers of the scaffold can
take the form of other warp knitted patterns.
[0084] As shown in FIGS. 8A-8C and 9, the second type of fibers 810
interconnect with the first type of fibers 808 of the first and
second knitted layers 802, 804 in a manner in which the first and
second fibers are non-fixedly attached and slidably interconnected.
As such, in this illustrated embodiment, the first and second type
of fibers 808, 810 can move relative to each other, thereby
allowing for movement and for expansion in the x-direction (e.g.,
stretch) and the y-direction (e.g., compression). Additionally, the
interconnection between the first and second type of fibers 808,
810 can affect, at least in part, the stiffness of the scaffold
800. For example, the tighter the interconnection, the stiffer the
scaffold 800.
[0085] Further, as shown in the FIGS. 8A-8C and 9, the first and
second knitted layers 802, 804 each include a plurality of openings
812 formed therein. The openings 812 of the first and second
knitted layers 802, 804 each have a perimeter formed of the first
and second types of fibers 808, 810. The openings 812 of the second
knitted layer 804 can have a size that is less than about 1/4 of a
width of a crown of a staple, like staple 406 in FIG. 5. As such,
in some implementations, the crown of the fired staple can span
over at least four openings 812 in the second knitted layer 804. In
one embodiment, the openings 812 can have a size that is about 1/8
of the width of the crown. While the crown of a staple can have a
variety of widths, in some implementations, the width of the crown
can be about 0.080 inches to 0.140 inches. In one embodiment, the
width of the crown is about 0.12 inches.
[0086] The plurality of openings 812 in the first and second
knitted layers 802, 804 can have a variety of sizes. For example,
the plurality of openings 812 in the second knitted layer 804 can
have a diameter from about 0.002 inches to 0.1 inches. As used
herein, "diameter" of an opening is the largest distance between
any pair of vertices of the opening.
[0087] As discussed above and shown in FIGS. 8A-8C and 9, the
scaffold 800 includes a support layer 806 that is positioned
between the first and second knitted layers 802, 804. The support
layer 806 is non-fixedly attached to first and second knitted
layers 802, 804. The support layer 806 can be configured such that
when the scaffold 800 is attached to a cartridge deck, like
cartridge deck 606 in FIG. 6, at least a portion of the second type
of fibers 810 of the support layer 806 are oriented in a direction
that is substantially non-parallel to the cartridge deck. While the
support layer 806 is shown in FIGS. 8A-8C and 9, to include only
the second type of fibers 810, which in this exemplary embodiment,
are monofilaments, it is also contemplated herein that the support
layer 806 can include additional types of fibers, including, for
example, the first type of fibers 808.
[0088] As shown, the fibers 810 of the support layer 806 are
arranged within the support layer 806 to form standing (spacer)
fibers 814 and a plurality of voids 816 therebetween. The standing
fibers 814 are non-fixedly attached to each other. Further, the
standing fibers 814 are non-fixedly and slidably interconnected to
the first type of fibers 808 of the first and second knitted layers
802, 804. In some implementations, the plurality of voids 816 can
be larger than the plurality of openings 812 in the first and
second knitted layers 802, 804.
[0089] The standing fibers 814 are configured to bend under force
applied to the scaffold 800 (e.g., when stapled to tissue). The
resilience of the standing fibers 814 permits, at least in part,
the scaffold to compress at various heights to thereby accommodate
tissue (T) with tissue portions of different thicknesses. That is,
independent of the particular tissue thickness, the sum of the
compressed heights of the captured tissue and scaffold within the
fired staple can be maintained, and thus can remain equal, or at
least substantially equal, to the height of the fired staple. In
this way, at least in part, the scaffold 800 can be configured to
apply a stress of at least about 3 g/mm.sup.2 to the captured
tissue for at least a predetermined period (e.g., at least about 3
days).
[0090] Generally, the material composition, the height, and/or the
transverse cross-sectional area of each standing fiber 814
controls, at least in part, its stiffness or ability to bend under
compression which, in turn, controls, at least in part, the
compressibility of the scaffold 800. Accordingly, the standing
fibers 814 can be configured to tune the compressibility of the
scaffold 800 to one or more desired values. For example, while the
standing fibers 814 in FIGS. 8B-8C and 9 are of the same material,
in some implementations, the support layer 806 can include standing
fibers of different materials with different stiffnesses.
Alternatively or in addition, in some implementations, the support
layer 806 can include standing fibers of different heights and/or
transverse cross-sectional areas. In one embodiment, the standing
fibers 814 can have a high length-to-diameter ratio, for example, a
ratio of about 25:1 to 6:1. In this way, the standing fibers 814
can further encourage tissue ingrowth and cell integration within
the implanted scaffold.
[0091] The amount of the standing fibers 814 within a certain
section of the support layer 806 can also affect, among other
things, the compressibility of such section, and thus the
compressibility of the scaffold 800. In certain instances, the
standing fibers 814 can be strategically concentrated in certain
sections of the support layer 806 to provide greater column
strength in such sections, for example. In at least one instance,
the standing fibers 814 can be concentrated in sections of the
support layer 806 that are configured to receive staples when the
staples are fired. Alternatively, the standing fibers 814 can be
concentrated in sections of the support layer 806 that do not
receive staples when the staples are fired.
[0092] The ratio of the voids 816 to the standing fibers 814 can
vary. In one implementation this ratio can be in the range of at
least about 3:1. In other implementations, the ratio of voids 816
to the standing fibers 814 can in the range of at least about 5:1
or of at least about 12:1. Further, at least a portion of the voids
816 in the support layer 806 can each have a different size. In
this way, the variable void sizes throughout the cross-section of
the scaffold 800 can promote extracellular remodeling. That is, the
variable void sizes can facilitate revascularization as well as
mobility of cells within the scaffold 800 when the scaffold is
implanted, thereby encouraging both tissue and cellular ingrowth.
Further the variable void sizes can also facilitate extraction of
byproducts and cellular waste from the implanted scaffold, and thus
the implantation site.
[0093] In some embodiments, the scaffold 800 can also include a
porous layer interconnected to the second knitted layer 804. In
this way, when the scaffold 800 is attached to a cartridge deck,
like cartridge deck 606 in FIG. 6, the porous layer would be
positioned between the cartridge deck and the second knitted layer
804. In one embodiment, the porous layer is fused or bonded to the
second knitted layer 804. The porous layer can be formed of a
material having a lower glass transition temperature than the
fibers 808, 810 of the scaffold 800. It is also contemplated herein
that the porous layer can be formed of a material having the same
or a higher glass transition temperature than at least one of the
fibers 808, 810 of the scaffold 800. The porous layer can have a
thickness that is less than about 0.003 inches. In one embodiment,
the porous layer has a thickness that is less than about 0.001
inches. The porous layer can also include pores that are greater
than about 0.0005 inches in diameter. For example, in some
implementations, the pores can vary in size from about 0.0005
inches to about 0.001 inches. Further, in some implementations, the
pores can make up at 50% of the surface area of the layer.
[0094] The scaffolds described herein, like scaffold 800 in FIGS.
8A-8C and 9, can be manufactured using any suitable methods. For
example, in one embodiment, the method can include forming a first
knitted layer, forming a second knitted layer, and interknitting
spacers with the first and second knitted layers. The first and
second knitted fibers can comprise fibers of a first polymer. The
first knitted layer can be configured to mate with a cartridge
deck. Interknitting the spacer fibers with the first and second
knitted layers can connect the first and second knitted layers
together in a spaced parallel relation. As used herein, a "spaced
parallel relation" means that the first and second layers extend
within planes that are distanced from and substantially parallel
with one another. The spacer fibers can be formed of only a second
polymer that is different than the first polymer. The first polymer
fibers can have a diameter that is different than a diameter of the
second polymer fibers. The spacer fibers can be integrated with and
extending between the first and second knitted layers. The method
can also include annealing the first and second knitted layers
interknitted with the spacer fibers.
[0095] The interknitting of the spacer fibers with the first and
second knitted layers can form a support layer therebetween. The
formation of the first knitted layer can include knitting the first
polymer fibers according to a predetermined pattern. The formation
of the second knitted layer can include knitting the first polymer
fibers according to a predetermined pattern. While the knitted
layers can each have various knitted patterns, in some
implementations, the knitted layers can each have a Rachel knit
pattern (e.g., as described in Example 1 below). A person skilled
in the art will appreciate that the knitted layers of the scaffold
can take the form of other warp knitted patterns.
[0096] FIG. 12A illustrates another exemplary embodiment of a
scaffold 1000. Aside from the differences described in detail
below, the scaffold 1000 can be similar in construction to the
scaffold 800 (FIGS. 8A-8C and 9) and is therefore not described in
detail herein. In this embodiment, the scaffold 1000 includes a
first knitted layer 1002 having a first portion 1004 and a second
portion 1006, each having outer and inner edges. The inner edges
1004a, 1006a define a channel 1008 that extends along the
longitudinal axis (L) of the scaffold 1000. The channel 1008 is
configured to receive a cutting member, such as a knife. As shown
in FIG. 12B, the channel 1008 does not extend completely through
the scaffold 1000. In particular, the channel 1008 does not extend
through the second knitted layer 1010. In this way, the scaffold
1000 is configured to have sufficient structural integrity to
thereby be effectively manipulated and attached to a cartridge
deck, like cartridge deck 2014 in FIG. 12B. In another embodiment,
as shown in FIG. 13, the scaffold 3000 can have a channel 3008 that
is perforated. In use, when the cutting member is initially fired
and travels along the scaffold 1000, the cutting member cuts
through the second knitted layer 1010, thereby separating the
scaffold 1000 into two pieces.
[0097] Further, as shown in FIG. 12A, the scaffold 1000 includes
flanges 1012 that are configured to mate with recessed channels,
like recessed channels 2016 of cartridge deck 2014 in FIG. 12B, as
further described below. While FIG. 12A illustrates the scaffold
1000 having flanges 1012 at one side of the scaffold 1000, there
are additional flanges 1012 positioned at the opposite side of the
scaffold 1000. A person skilled in the art will appreciate that the
number and placement of flanges 1012 are not limited to what is
shown in FIG. 12A. While the flanges 1012 can be made of a variety
of materials, in some implementations, as shown in FIG. 12A, the
flanges 1012 are an extension of the second knitted layer 1010. In
other embodiment, the flanges 1010 can be formed of different
material and formed in-line or offline with the other components of
the scaffold 1000. A person skilled in the art will appreciate that
the flanges can be formed of the same or different materials than
that of the first and/or second knitted layers of the scaffold and
can be attached thereto by any suitable method.
[0098] FIG. 12B illustrates another exemplary embodiment of a
staple cartridge assembly 2000. Aside from the differences
described in detail below, the staple cartridge assembly 2000 can
be similar to staple cartridge assembly 600 (FIG. 6) and is
therefore not described in detail herein. Further, for purposes of
simplicity, certain components of the staple cartridge assembly
2000 are not illustrated in FIG. 12B.
[0099] The staple cartridge assembly 2000 includes the scaffold
1000 in FIG. 12A attached to a cartridge deck 2014 having recessed
channels 2016. The scaffold 1000 can be attached to the cartridge
deck using any suitable methods, as described in more detail below.
As shown, the recessed channels 2016 are configured to receive the
flanges 1012 such that the flanges 1012 can attach to the side(s)
of the cartridge deck. In this way, the scaffold 1000 can be more
securely attached to the cartridge deck 2014, thereby preventing
undesired movement of the scaffold 1000 during use.
[0100] The scaffolds can be applied to a cartridge deck to form a
staple cartridge assembly using any suitable method. For example,
in some embodiments, the method can include heating a cartridge
deck and positioning a scaffold against a surface of the cartridge
deck. The scaffold can include first and second type of fibers in
which the first type of fibers are predominately present. As used
herein, "predominately present" when used to describe the amount of
particular fibers in a layer means an amount that is greater than
50% of the total amount fibers within that layer. The first type of
fibers can have a first glass transition temperature and the second
type of fibers can have a second glass transition temperature that
is less than the first glass transition temperature. The cartridge
deck can be heated to a temperature of at least the second glass
transitions temperature. The method can also include cooling the
cartridge deck and scaffold applied thereto to a temperature that
is less than the second glass transition temperature.
[0101] The scaffold can include first and second knitted layers
each having the first and second types of fibers and a support
layer disposed between the first and second knitted layers. In such
instance, the positioning of the scaffold against the surface of
the cartridge deck can include placing the first knitted layer
against the surface and applying force to the scaffold such that
the first knitted layer bonds and conforms to a shape of the
surface. The support layer can be formed of the second type of
fibers.
[0102] The instruments disclosed herein can be designed to be
disposed of after a single use, or they can be designed to be used
multiple times. In either case, however, the instrument can be
reconditioned for reuse after at least one use. Reconditioning can
include any combination of the steps of disassembly of the
instrument, followed by cleaning or replacement of particular
pieces and subsequent reassembly. In particular, the instrument can
be disassembled, and any number of the particular pieces or parts
of the instrument can be selectively replaced or removed in any
combination. Upon cleaning and/or replacement of particular parts,
the instrument can be reassembled for subsequent use either at a
reconditioning facility, or by a surgical team immediately prior to
a surgical procedure. Those skilled in the art will appreciate that
reconditioning of an instrument can utilize a variety of techniques
for disassembly, cleaning/replacement, and reassembly. Use of such
techniques, and the resulting reconditioned instrument, are all
within the scope of the present application.
[0103] The present teachings may be further understood with
reference to the following non-limiting examples.
EXAMPLES
Example 1: Manufacturing of a Scaffold
[0104] A sample having two knitted layers and a support layer
positioned therebetween was prepared. The two knitted layers were
each formed of Vicryl fibers (multifilament fibers of Vicryl) and
the support layer was formed of Polydioxanone (PDS) fibers
(monofilament fibers of PDS), details of which are provided in
Table 1 below.
TABLE-US-00001 TABLE 1 Vicryl and Polydioxanone Fiber Information
Fiber Diameter Ten Elongation Fiber (mils) (lbf) (%) 7-0 PDS, dyed
3.18 0.67 38.28 2 ply, 28 denier Vicryl, natural 1.17 0.58
20.34
[0105] The sample was warp knit using a 16 gauge double needle bar
Raschel knitting machine with a six guide bar (GB) construction.
Each guide bar was individually controlled using a pattern chain,
the patterns for which can be found in Table 2 below. PDS was used
in the support layer and Vicryl was used for the knitted
layers.
TABLE-US-00002 TABLE 2 Pattern Chain Guide Fiber Bars Guide Bar
Movement Threading Used 1 1-0; 0-0/1-2; 2-2/2-3; 3-3/2-1; 1-1//
Fully Vicryl 2 2-3; 3-3/2-1; 1-1/1-0; 0-0/1-2; 2-2// Threaded
Vicryl 3 (1-0; 2-3) X 4// PDS 4 (2-3; 1-0) X 4// PDS 5 2-2;
2-3/3-3; 2-1/1-1; 1-0/0-0; 1-2// Vicryl 6 1-1; 1-0/0-0; 1-2/2-2;
2-3/3-3; 2-1// Vicryl
[0106] Approximately 6.4 yards of 5 inch wide sample was produced.
The sample was scoured with isopropyl alcohol. The sample was
placed on a roll, sealed in a nitrogen purged foil bag, and kept
under nitrogen flow until further processing.
[0107] An approximate 5 inch.times.5 inch segment of the sample was
then annealed using cycle conditions as described in Table 3.
TABLE-US-00003 TABLE 3 Cycle Conditions N.sub.2 Purge Ramp Up
Annealing Cool Down Hours/ Minutes/ Hours/ Minutes/ Temperature
Temperature Speed Temperature Temperature (.degree. C.) (.degree.
C.) (.degree. C./min) (.degree. C.) (.degree. C.) 1/30 90/85 0.94/1
6/85 60/30
[0108] The annealed sample was then cut to produce approximately 5
mm.times.10 mm sample scaffolds. One of the scaffold samples was
examined by optical microscopy (OM) and SEM. Various OM images of
the sample scaffold is shown in FIGS. 8A-8C, and a cross-sectional
SEM image of the scaffold sample is shown in FIG. 9.
Example 2: Cellular Ingrowth and Limited Inflammation
[0109] Sample scaffolds as prepared in Example 1 were
subcutaneously implanted for up to 90 days into rabbits injected
with a hematoxylin and eosin stain (H&E) stain. Histopathology
images of an implanted scaffold removed at 60 days is illustrated
in FIGS. 10A-10B and an implanted scaffold removed at 90 days is
illustrated in FIGS. 11A-11B. The white ovals/circles shown in
these images are fibers of the scaffold cut either perpendicular or
slightly off. As shown, the black boxes illustrate some of the
portions of the scaffold in which tissue ingrowth occurred during
implantation. Additionally, the arrows in FIGS. 10B and 11B point
to inflammatory areas around the fibers, which are indicative of
the inflammation phase of healing.
[0110] One skilled in the art will appreciate further features and
advantages of the invention based on the above-described
embodiments. Accordingly, the invention is not to be limited by
what has been particularly shown and described, except as indicated
by the appended claims. All publications and references cited
herein are expressly incorporated herein by reference in their
entirety. Any patent, publication, or information, in whole or in
part, that is said to be incorporated by reference herein is
incorporated herein only to the extent that the incorporated
material does not conflict with existing definitions, statements,
or other disclosure material set forth in this document. As such
the disclosure as explicitly set forth herein supersedes any
conflicting material incorporated herein by reference.
* * * * *