CN112040885A

CN112040885A - Knitted tissue scaffold

Info

Publication number: CN112040885A
Application number: CN201980027115.0A
Authority: CN
Inventors: M·J·温德里; V·达勒桑德罗; J·L·哈里斯; F·E·谢尔顿四世
Original assignee: Ethicon LLC
Current assignee: Ethicon LLC
Priority date: 2018-02-21
Filing date: 2019-01-21
Publication date: 2020-12-04
Also published as: BR112020017001A2; JP2021514250A

Abstract

Staple cartridge assemblies for use with surgical stapling instruments and methods of making the same are provided. The present invention also provides a stent for use with a surgical staple cartridge and a method of making the same.

Description

Knitted tissue scaffold

Technical Field

The invention provides a knitted tissue scaffold and a manufacturing method thereof.

Background

Surgical staplers are used in surgical procedures to close openings in tissues, vessels, ducts, shunts, or other objects or body parts involved in a particular procedure. These openings may be naturally occurring, such as blood vessels or passages in internal organs like the stomach, or they may be formed by the surgeon during surgery, such as by puncturing tissue or blood vessels to form bypasses or anastomoses or by cutting tissue during a stapling procedure.

Some surgical staplers require the surgeon to select the appropriate staple having the appropriate staple height for the tissue being stapled. For example, the surgeon may select long staples for thick tissue and short staples for thin tissue. However, in some cases, the tissue being stapled does not have a uniform thickness, and thus, the staples may not achieve the desired fired configuration at each staple site. Thus, the desired seal cannot be formed at or near all suture sites, allowing blood, air, gastrointestinal fluids, and other fluids to seep through the unsealed sites.

In addition, staples and other objects and materials that can be implanted in conjunction with a procedure similar to suturing often lack some of the characteristics of the tissue in which they are implanted. For example, staples and other objects and materials may lack the natural flexibility of the tissue in which they are implanted and therefore cannot withstand the varying intra-tissue pressures at the implantation site. This can lead to undesirable tissue tearing and thus leakage at or near the staple site and/or between the apposed implant and the tissue.

Accordingly, there remains a need for improved instruments and methods for addressing the current problems of surgical staplers.

Disclosure of Invention

A staple cartridge assembly for use with a surgical stapling instrument is provided.

In one exemplary embodiment, the staple cartridge assembly may comprise: a staple cartridge having a plurality of staples and a cartridge deck; and a knitted elastically deformable, bioabsorbable scaffold attached to the cartridge platform and formed of at least three distinct regions each having a different function, wherein the staples are deployable through the scaffold into tissue captured against the scaffold. The stent may include: a first tissue region, the first tissue region being configurable to promote tissue ingrowth; a second knitted zone that can be configured to be conformable (conformable) for attachment to the cartridge platform; and a spacer region disposed between the first and second knit regions and configurable to support the first and second knit regions, wherein there is an opening in the first and second knit regions and a void in the spacer region, wherein the void is larger than the opening. The first knitted zone may comprise first fibers made of a first bioabsorbable polymer and second fibers made of a second bioabsorbable polymer, wherein a fiber diameter of each first fiber is less than a fiber diameter of each second fiber. The second knitted zone may include the first fiber and the second fiber of the first knitted zone. The spacer regions may be formed by the second fibers, wherein the second fibers are non-fixedly and slidably interconnected to the first fibers of the first knitted region and the first fibers of the second knitted region. In one aspect, the stent may be configured to apply at least about 3g/mm to captured tissue when the stent is in a tissue deployed state²For at least 3 days.

In some aspects, the fiber diameter of the first fibers may be about 1/5 to 1/20 of the fiber diameter of the second fibers. In other aspects, the fiber diameter of the first fibers can be about 1/10 the fiber diameter of the second fibers.

In one aspect, the second fibers may extend from the first knit region to the second knit region such that the second fibers extend across the spacer regions, and at least a portion of the second fibers within the spacer regions may be oriented substantially perpendicular to the first fibers of the first knit region and the first fibers of the second knit region.

The first type of fibers and the second type of fibers may be formed from a variety of materials. In one aspect, the first type of fiber may be formed from at least one of: poly-L-lactic acid, copolymers of glycolide and L-lactide, copolymers of glycolic acid and lactic acid, poly (lactic acid) poly (lactic acid-glycolic acid copolymer), poly (lactic acid), polyglycolide, and copolymers of glycolide, caprolactone, trimethylene carbonate and lactide. In another aspect, the second type of fibers may be formed from at least one of: polydioxanone, copolymers of polydioxanone and polyglycolide, copolymers of lactide and polycaprolactone, copolymers of glycolide, dioxanone, and trimethylene carbonate, poly (trimethylene carbonate), polyhydroxyalkanoate, and polygluconate.

In another embodiment, a staple cartridge assembly is provided and can comprise: a staple cartridge having a plurality of staples and a cartridge deck; and a knitted elastically deformable, bioabsorbable scaffold attached to the cartridge platform and formed of at least three distinct regions each having a different function, wherein the staples are deployable through the scaffold into tissue captured against the scaffold. The stent may include a first zone that may have a knit structure and may be configured to promote tissue ingrowth, wherein the first zone comprises first fibers made of a first bioabsorbable polymer. The stent may further include a second zone, which may be formed of second fibers made of a second bioabsorbable polymer, and which may be 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. The fiber diameter of each first fiber may be less than the fiber diameter of each second fiber, and wherein there is an opening in the first zone and a void in the second zone, wherein the void is larger than the opening.

In some aspects, the stent can further comprise a third zone, which can have a knit structure and can be configured to conform for attachment to the cartridge platform, which can be a hollow structureThe third zone may comprise the first fibers, and the second zone may be located between the first zone and the third zone. In such cases, the second fibers may be non-fixedly and slidably interconnected to the first fibers of the third zone, wherein the second fibers may 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 stent may be configured to apply at least about 3g/mm to captured tissue when the stent is in a tissue deployed state²For at least 3 days.

A rack is provided for use with a surgical staple cartridge and may include: a first knit region configured to promote tissue ingrowth; a second knit region configured to conform to for attachment to a cartridge platform; and a spacer region disposed between the first and second knit regions and configured to support the first and second knit regions, wherein there is an opening in the first and second knit regions and a void in the spacer region, wherein the void is larger than the opening. The first knitted zone may comprise first fibers made of a first bioabsorbable polymer and second fibers made of a second bioabsorbable polymer, wherein a fiber diameter of each first fiber is less than a fiber diameter of each second fiber. The second knitted zone may include the first fiber and the second fiber of the first knitted zone. The spacer regions may be formed by the second fibers, wherein the second fibers may be non-fixedly and slidably interconnected to the first fibers of the first knitted region and the first fibers of the second knitted region.

Drawings

This patent or patent application document contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the U.S. patent and trademark office upon request and payment of the necessary fee.

The present invention will be more fully understood from the detailed description given below in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of an exemplary embodiment of a conventional surgical stapling and severing instrument;

FIG. 2 is a perspective view of a wedge sled of a staple cartridge of the surgical stapling and severing instrument of FIG. 1;

FIG. 3 is a perspective view of a knife and firing bar ("E-beam") of the surgical stapling and severing instrument of FIG. 1;

FIG. 4 is a longitudinal cross-sectional view of a surgical cartridge that may be disposed within the stapling and severing instrument of FIG. 1;

FIG. 5 is a top view of staples that can be disposed within a staple cartridge of the surgical cartridge assembly of FIG. 4 in an unfired (pre-deployed) configuration;

FIG. 6 is a longitudinal cross-sectional view of an exemplary embodiment of a surgical cartridge assembly having a bracket attached to a cartridge platform;

FIG. 7 is a schematic view showing the stent of FIG. 6 when sutured to tissue;

FIG. 8A is an enlarged top view of an exemplary embodiment of a bracket attachable to a cartridge platform of the surgical cartridge assembly of FIG. 6;

FIG. 8B is an enlarged cross-sectional view of the stent of FIG. 8A taken at B-B;

FIG. 8C is another enlarged cross-sectional view of the stent of FIG. 8A taken at C-C;

FIG. 9 is a Scanning Electron Micrograph (SEM) image of the stent of FIGS. 8A-8C at a 500 μm scale;

fig. 10A is a histopathological image of the implanted stent removed at day 60 as discussed in example 2.

FIG. 10B is an enlarged view of segment 10B of FIG. 10A;

fig. 11A is a histopathological image of an implanted stent removed at 90 days as discussed in example 2;

FIG. 11B is an enlarged view of segment 11B of FIG. 11A;

FIG. 12A is a perspective view of another exemplary embodiment of a stent;

FIG. 12B is another exemplary embodiment of a staple cartridge assembly having the stent of FIG. 12A attached to a cartridge deck; and is

Fig. 13 is a bottom view of another exemplary embodiment of a stent.

Detailed Description

Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices, 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. Features illustrated or described in connection with one exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.

Moreover, in the present disclosure, similarly named components in various embodiments typically have similar features, and thus, in particular embodiments, each feature of each similarly named component is not necessarily fully described. Further, 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 may be used in connection with such systems, instruments, and methods. Those skilled in the art will recognize that the equivalent dimensions of such linear and circular dimensions can be readily determined for any geometric shape. The size and shape of the systems and instruments and their components may depend at least on the anatomy of the subject in which the systems and instruments will be used, the size and shape of the components with which the systems and instruments will be used, and the methods and procedures in which the systems and instruments will be used.

It should be understood that the terms "proximal" and "distal" are used herein with respect to a user, such as a clinician, grasping a handle of an instrument. Other spatial terms such as "anterior" and "posterior" similarly correspond to distal and proximal, respectively. It will also be appreciated that, for convenience and clarity, spatial terms such as "vertical" and "horizontal" are used herein in connection with the illustrations. However, surgical instruments are used in many orientations and positions, and these spatial terms are not intended to be limiting and absolute.

Values or ranges can be expressed herein as "about" and/or from "about" one particular value to another particular value. When such values or ranges are expressed, other embodiments disclosed include the particular values recited and/or from one particular value to another particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the various values disclosed herein and the particular values form another embodiment. It will also be understood that numerous values are disclosed herein, and that each value is also disclosed herein as "about" that particular value in addition to the value itself. In embodiments, "about" can be used to indicate, for example, within 10% of the recited value, within 5% of the recited value, or within 2% of the recited value.

For the purposes of describing and defining the present teachings, it is noted that 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, unless otherwise specified. The term "substantially" may also be used 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.

The invention provides a surgical staple cartridge assembly and a method of making the same. In general, a staple cartridge assembly is provided having a staple cartridge that includes a cartridge deck having a plurality of staples disposed therein. The staple cartridge assembly also includes a knitted, elastically deformable, bioabsorbable stent configured to releasably mate with the cartridge deck and allow staples to be deployed through the stent into tissue. The scaffold is releasably matable with the cartridge deck such that at least a portion of the scaffold is attachable to tissue captured by the staples as the staples are deployed from the cartridge deck into the tissue. As described herein, a stent may be configured to compensate for changes in tissue properties, such as changes in tissue thickness, and/or to promote tissue ingrowth as the stent is sutured to the tissue. For example, the stent can be configured to apply at least about 3g/mm to tissue when in a tissue deployed state (e.g., when the stent is sutured to tissue in vivo)²For at least 3 days. An exemplary staple cartridge assembly may include a plurality of features to facilitate the application of surgical staples, as described herein and shown in the figures. However, those skilled in the art will appreciate that the staple cartridge assembly may include only some of these features and/or the staple cartridge assembly may include a variety of other features known in the art. The staple cartridge assemblies described herein are intended to be merely representative of certain exemplary embodiments. Further, while the cartridge is described in connection with a surgical staple cartridge assembly, the cartridge may be used in connection with any type of surgical instrument.

Fig. 1 illustrates an exemplary surgical stapling and severing instrument 100 suitable for use with an implantable adjunct, such as a stent. The surgical stapling and severing instrument 100 may include an anvil 102 that may be repeatedly opened and closed about its pivotal attachment to an elongate staple channel 104. The staple applying assembly 106 can include an anvil 102 and a channel 104, wherein the assembly 106 can be attached proximally to an elongate shaft 108 that forms a tool portion 110. When the staple applying assembly 106 is closed, or at least substantially closed, the tool portion 110 may present a sufficiently small cross-section that is suitable for insertion of the staple applying assembly 106 through a trocar. While the instrument 100 is configured to staple and sever tissue, surgical instruments configured to staple without severing tissue are also contemplated herein.

In various instances, the staple applying assembly 106 is manipulated by a handle 112 that is connected to the elongate shaft 108. The handle 112 may include: user controls such as a knob 114 that rotates the elongate shaft 108 and the staple applying assembly 106 about the longitudinal axis of the elongate shaft 108; and a closure trigger 116 that may pivot forward of the pistol grip 118 to close the staple applying assembly 106. For example, when the closure trigger 116 is clamped, the closure release button 120 resides outwardly on the handle 112 such that the closure release button 120 can be depressed to release the closure trigger 116 and open the staple applying assembly 106.

A firing trigger 122, which is pivotable in front of the closure trigger 116, causes the staple applying assembly 106 to simultaneously sever and staple tissue clamped therein. In various circumstances, multiple firing strokes may 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 may include one or more rotatable indicator wheels, such as a rotatable indicator wheel 124 that may indicate the progress of firing. If desired, a manual firing release lever 126 may allow the firing system to retract before full firing travel is complete, and further, in the event of a stuck and/or failed firing system, the firing release lever 126 may allow a surgeon or other clinician to retract the firing system.

Additional details regarding 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. patent No. 9332984 and 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 rather includes a housing configured to be coupled to a surgical robot, for example, as described in U.S. patent application No. 15/689198 to frederick e.shelton et al, filed on 29/8/2017, the disclosure of which is incorporated herein by reference in its entirety.

In connection with fig. 2 and 3, a firing assembly (such as, for example, firing assembly 228) may be used with a surgical stapling and severing instrument (such as instrument 100 of fig. 1) to advance a wedge sled 230 comprising a plurality of wedges 232 configured to deploy staples from a staple applying assembly (such as staple applying assembly 106 of fig. 1) into tissue captured between an anvil (such as anvil 102 of fig. 1) and an elongate staple channel (such as channel 104 of fig. 1). In addition, an E-beam 233 at a distal portion of the firing assembly 228 can fire 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 that may follow a portion 238 of the wedge sled 230, and a bottom pin or foot 240, and a sharp cutting edge 242 that may be configured to sever captured tissue as the firing assembly 228 is advanced distally. In addition, integrally formed proximally projecting top guide 244 and middle guide 246 that cradle each vertical end of cutting edge 242 may further define a tissue staging area 248, thereby helping to guide tissue to sharp cutting edge 242 prior to severing the tissue. The middle guide 246 can also be used to engage and fire the staple applying assembly through a stepped central member 250 that abuts a wedge sled 230 that effects staple formation through the staple applying assembly.

Referring to FIG. 4, a staple cartridge 400 may be used with a surgical stapling and severing instrument (such as surgical stapling and severing instrument 100 of FIG. 1) and may include a cartridge deck 402 and a plurality of staple cavities 404. Staples 406 may, for example, be removably positioned in each staple cavity 404. The staples 406 are shown in greater detail in FIG. 5 in an unfired (pre-deployed) configuration. The staple cartridge 400 can further comprise a longitudinal channel that can be configured to receive a firing and/or cutting member, such as an E-beam, e.g., E-beam 233 of FIG. 3.

Each nail 406 may include a crown (base) 406_CAnd from crown 406_CExtended leg or legs 406_L. Before the staples 406 are deployed, the crowns 406 of the staples 406_CCan be formed by staples positioned within the staple cartridge 400The driver 408 supports, and at the same time, the legs 406 of the staples 406_LCan be at least partially received within the staple cavity 404. Additionally, when the staples 406 are in their unfired positions, the staple legs 406 of the staples 406_LMay extend beyond the tissue contacting surface 410 of the staple cartridge 400. In some cases, as shown in FIG. 5, the staple legs 406_LMay include a sharp point that can cut into and penetrate tissue.

The staples 406 may be deployed between unfired and fired positions such that 406_LMoves through the staple cavities 404, penetrates tissue positioned between and contacts an anvil (e.g., anvil 102 in fig. 1) and the staple cartridge 400. At the leg 406_LThe legs 406 of each staple 406 when deformed against the anvil_LA portion of tissue may be captured within each staple 406 and a compressive force applied to the tissue. In addition, the leg 406 of each staple 406_LTowards the crown 406 of the nail 406_CDeformed downwardly to form a staple entrapment zone in which tissue can be captured. In various instances, a staple entrapment area can be defined between an inner surface of the deformed leg and an inner surface of the crown of the staple. For example, the size of the staple entrapment area may depend on several factors, such as the length of the legs, the diameter of the legs, the width of the crown, and/or the degree of deformation of the legs.

In use, an anvil (e.g., anvil 102 in FIG. 1) may be moved to a closed position by depressing a closure trigger (e.g., closure trigger 116 in FIG. 1) to advance an E-beam (e.g., E-beam 233 in FIG. 3). The anvil can position tissue against the tissue contacting surface 410 of the staple cartridge 400. Once the anvil has been properly positioned, staples 406 may be deployed.

To deploy the staples 406, a staple firing sled (such as sled 230 in fig. 2) can be moved from the proximal end 400p toward the distal end 400d of the staple cartridge 400, as described above. When the firing assembly (e.g., the firing assembly 228 of FIG. 3) is advanced, the sled can contact the staple drivers 408 and lift the staple drivers 408 upward within the staple cavities 404. In at least one example, the sled and staple drivers 408 can each comprise one or more ramps or inclined surfaces that can cooperate to move the staple drivers 408 upwardly from their unfired positions. When the staple drivers 408 are lifted upward within their respective staple cavities 404, the staple drivers 408 can lift the staples 406 upward so that the staples 406 can emerge from their staple cavities 404 and penetrate into the tissue. In various instances, as part of the firing sequence, the sled can simultaneously move several staples upward.

One skilled in the art will appreciate that while a stent is shown and described below, the stents disclosed herein may be used with other surgical instruments and need not be coupled to a staple cartridge as described herein.

As noted above, with some surgical staplers, a surgeon typically needs to select the appropriate staples having the appropriate staple heights for the tissue to be stapled. For example, the surgeon may select long staples for thick tissue and short staples for thin tissue. However, in some cases, the tissue being stapled does not have a consistent thickness, and thus the staples may not achieve the desired firing configuration at each section of stapled tissue (e.g., thick and thin tissue sections). When staples having the same or substantially the same height are used, particularly when the staple sites are exposed to pressure within the tissue at the staple sites and/or along the staple line, the inconsistent thickness of the tissue can also lead to undesirable leakage and/or tearing of the tissue at the staple sites.

Accordingly, the present invention provides various embodiments of a stent configured to compensate for different thicknesses of tissue captured within fired (deployed) staples to avoid the need to consider staple height when stapling tissue during a surgical procedure. That is, the stents described herein may allow a set of staples having the same or similar height to be used to staple different thicknesses of tissue (i.e., from thin tissue to thick tissue), while also providing sufficient tissue compression within and between the firing staples in combination with the stents. Thus, the stents described herein can maintain suitable compression of thin or thick tissue stapled thereto, thereby minimizing leakage and/or tearing of the tissue at the staple site.

Alternatively or additionally, the scaffold may be configured to promote tissue ingrowth. In various instances, it is desirable to promote tissue ingrowth in an implanted stent to promote healing of the treated tissue (e.g., sutured and/or incised tissue) and/or to accelerate recovery of the patient. More specifically, tissue ingrowth in the implanted scaffold can reduce the incidence, extent, and/or duration of inflammation at the surgical site. Tissue ingrowth in and/or around the implanted scaffold may manage the spread of infection at, for example, the surgical site. The ingrowth of blood vessels, and in particular white blood cells, for example in and/or around an implantable stent can counteract infection in and/or around the implanted stent and adjacent tissues. Tissue ingrowth can also promote the acceptance of foreign objects (e.g., implantable stents and staples) by the patient's body and can reduce the likelihood of patient body rejection. Rejection of foreign material may result in infection and/or inflammation at the surgical site.

Generally, the stents provided herein are designed and positioned atop a staple cartridge (such as staple cartridge 400 in FIG. 4) such that when the staples are fired (deployed) from the staple cartridge deck of the staple cartridge, the staples penetrate the stent and into the tissue. When the legs of the staples are deformed against an anvil positioned opposite the cartridge assembly, the deformed legs capture a portion of the scaffold and a portion of the tissue within each staple. That is, at least a portion of the cradle is positioned between the tissue and the fired staples as the staples are fired into the tissue. While the brackets described herein are configured to attach to a staple cartridge of a staple cartridge assembly, it is also contemplated herein that the brackets may be configured to mate with other instrument components, such as jaws of a surgical stapler.

FIG. 6 illustrates an exemplary embodiment of a staple cartridge assembly 600 including a staple cartridge 602 and a stent 604. Staple cartridge 602 may be similar to staple cartridge 400 (FIG. 4), except for the differences described in detail below, and therefore, is not described in detail herein. As shown, a carrier 604 is positioned against staple cartridge 602. The staple cartridge can include a cartridge deck 606 and a plurality of staples 608, such as staples 406 shown in fig. 4 and 5. The pins 608 may be of any suitable unformed (pre-deployed) height. For example, the pins 608 may have an unformed height of between about 2mm to 4.8 mm. Prior to deployment, the crowns of the staples 608 may be supported by staple drivers 610.

In the illustrated embodiment, the stent 604 can mate with an outer surface 612 (e.g., a tissue contacting surface) of the cartridge platform 606. The outer surface 612 of the cartridge platform 606 can include one or more attachment features. The one or more attachment features can be configured to engage the bracket 604 to avoid undesired movement of the bracket 604 relative to the cartridge deck 606 and/or premature release of the bracket 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.

The stent 604 is elastically deformable to allow the stent to compress to different heights to compensate for different tissue thicknesses captured within the deployed staples. The stent 604 has an uncompressed (undeformed) or pre-deployed height and is configured to be deformable to one of a plurality of compressed (deformed) or deployed heights. For example, the uncompressed height of the bracket 604 can be greater than the fired height of the staples 608 (e.g., the height (H) of the fired staples 608a in fig. 7). In one embodiment, the uncompressed height of the stent 604 can be about 10% higher, about 20% higher, about 30% higher, about 40% higher, about 50% higher, about 60% higher, about 70% higher, about 80% higher, about 90% higher, or about 100% higher than the fired height of the staples 608. In certain embodiments, the uncompressed height of the stent 604 can be more than 100% higher than the fired height of the staples 608, for example.

The bracket 604 can releasably engage the outer surface 612 of the cartridge platform 606. As shown in FIG. 7, when the staples are fired, the tissue (T) and a portion of the stent 604 are captured by the fired (formed) staples 608 a. As described above, the firing staples 608a define a trapped region therein for receiving the captured stent 604 and tissue (T). The entrapment area defined by the firing staples 608a is at least partially limited by the height (H) of the firing staples 608 a. For example, the height of the firing staples 608a can be about 0.130 inches or less. In some embodiments, the height of the firing staples 608a can be about 0.025 inches to 0.130 inches. In some embodiments, the firing staples 608a can have a height of about 0.030 inches to 0.100 inches.

As described above, the cradle 604 can be compressed within a plurality of firing staples regardless of 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 2.75mm, for example, wherein the tissue (T) and stent 604 can be compressed within this height. In some cases, the tissue (T) may have a compressed height of about 1.0mm, and the scaffold 604 may have a compressed height of about 1.75 mm. In some cases, the tissue (T) may have a compressed height of about 1.50mm, and the scaffold 604 may have a compressed height of about 1.25 mm. In some cases, the tissue (T) may have a compressed height of about 1.75mm, and the scaffold 604 may have a compressed height of about 1.00 mm. In some cases, the tissue (T) may have a compressed height of about 2.00mm, and the scaffold 604 may have a compressed height of about 0.75 mm. In some cases, the tissue (T) may have a compressed height of about 2.25mm, and the scaffold 604 may have a compressed height of about 0.50 mm. Thus, the sum of the compressed heights of the captured tissue (T) and the cradle 604 can be equal to, or at least substantially equal to, the height (H) of the firing staples 608 a.

As discussed in more detail below, the structure of the stent may be configured such that when the stent and tissue are captured within the firing staples, the stent may exert a stress that can withstand the pressure of circulating blood through the tissue. Hypertension is generally considered to be 210mmHg, so it is desirable that the stent apply 210mmHg or more (e.g., 3 g/mm) to the tissue²) For a predetermined period of time (e.g., 3 days). Thus, in certain embodiments, the scaffold can be configured to apply at least about 3g/mm to the captured tissue²For at least 3 days. The stent is in a tissue deployed state when the stent is sutured to tissue in vivo. In one embodiment, the applied stress may be about 3g/mm². In another embodiment, the applied stress may be greater than 3g/mm². In yet another embodiment, the stress may be at least about 3g/mm²And applied to the captured tissue for more than 3 days. For example, in one embodiment, the stress may be at least about 3g/mm²And applied to the captured tissue for about 3 to 5 days.

Configured to apply at least about 3g/mm to the captured tissue for design purposes²The principle of hooke's law (F ═ kD) can be used for stents stressed for a predetermined time. For example, when the force (stress) to be applied to the captured tissue is knownA stent with stiffness (k) can be designed. The stiffness can be set by adjusting the material and/or the geometry of the stent (e.g., type and/or diameter of the fibers and/or interconnectivity of the fibers). Additionally, a stent may be designed with a maximum amount of compressive displacement for a minimum tissue thickness (e.g., 1mm), so the displacement length D may be a combination of the minimum tissue thickness (e.g., 1mm) plus the tissue thickness when stapled to tissue at a given maximum staple height (e.g., 2.75 mm). By way of example, in one embodiment, a stent may be configured to have a height of 2.75mm greater than the maximum formed suture height, and configured to compress to a height of 1.75mm when sutured to tissue having a minimum thickness of 1 mm. Thus, the compressibility of the scaffold may be varied to maintain a constant displacement length D, such that the stiffness (k) and overall thickness (D) of the captured tissue and scaffold may impose 3g/mm on the captured tissue²Of the stress of (c). It should be noted that one of ordinary skill in the art will appreciate that the foregoing formula may be modified to account for temperature changes, for example, when bringing the adjunct from room temperature to body temperature after implantation.

Additionally, the scaffold may be further developed to provide substantially continuous stress (e.g., 3 g/mm) to the captured tissue²) For a predetermined time (e.g., 3 days). To achieve this, the degradation rate of the stent material and the rate of tissue ingrowth within the stent need to be considered when designing the stent. In doing so, the scaffold may be designed such that the stiffness of the scaffold and/or the total thickness of captured tissue and scaffold may not affect less than 3g/mm²The manner of the applied stress varies.

The stent is sutured to the tissue under various suturing conditions (e.g., tissue thickness, height of the formed staples, pressure within the tissue). Depending on the suturing conditions, the amount of effective stress that the stent needs to be able to apply to the tissue to prevent tissue tearing and leakage can be determined. For example, in one embodiment, the effective stress amount is at least about 3g/mm². In order for the stent to provide an effective amount of stress to the tissue, the stent may be designed to effectively compensate for various suturing conditions. Thus, the stent may be customized to assume different compressed heights when sutured to tissue. Due to the fact thatThere is a limited range of in-tissue pressures, tissue thicknesses, and formed staple heights, and thus a suitable material and/or geometry for the stent can be determined that is effective to apply a substantially continuous desired stress (e.g., 3 g/mm) to the tissue when the stent is sutured to the tissue under a range of suturing conditions²) For a given amount of time (e.g., at least 3 days). That is, as described in more detail below, the inventive stent is formed of a compressible material and is geometrically configured to allow the stent to compress to various heights in a predetermined plane when sutured to tissue. In addition, this varying response of the stent may also allow the stent to maintain its continuous desired stress on the tissue when exposed to pressure fluctuations within the tissue (e.g., blood pressure spikes) that may occur when the stent is sutured to the tissue.

The stent may have a variety of configurations. For example, in certain embodiments, the stent may comprise at least one knitted layer and at least one supporting layer. As used herein, "knit layer" is used synonymously with "knit regions" and "support layer" is used synonymously with "spacer regions".

Fig. 8A-8C and 9 show an exemplary embodiment of a stent 800 having a first knit layer 802 and a second knit layer 804 with a support layer 806 disposed between the first knit layer and the second knit layer. In this illustrated embodiment, the first layer of knitting 802 can be configured to be positioned against tissue and the second layer of knitting 804 can be configured to be positioned against a cartridge platform (e.g., cartridge platform 606 in fig. 6).

As shown, the

knitted layers

802, 804 include a first type of fibers 808 and a second type of fibers 810, and the support layer 806 includes a second type of fibers 810. Thus, by having the stent 800 formed from two

different fibers

808, 810, the stent may have a variable stiffness profile over time after implantation. For example, the first type of fibers 808 may be used as a structural component of the

knitted layers

802, 804, and the stiffness profile may be a function of the degradation profile of the first type of fibers 808 and the interaction between the first type of fibers 808 and the second type of fibers 810 in the

knitted layers

802, 804.

In addition, the

knitted layers

802, 804 can be configured such that at least a portion of the first type of fibers 808 are oriented in a direction substantially parallel to the cartridge platform when the stent 800 is attached to the cartridge platform. While the first type of fibers 808 and the second type of fibers 810 can have a variety of sizes, in some implementations, the fiber diameter of the first type of fibers 808 is smaller than the fiber diameter of the second type of fibers 810.

While the

fibers

808, 810 of the knit layers 802, 804 and the fibers 810 of the support layer 806 can 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 fig. 8A-8C and 9. As used herein, the term "monofilament fiber" has its own ordinary and conventional meaning and may include fibers formed from a single filament. As used herein, the term "multifilament fiber" has its own ordinary and customary meaning and may include fibers formed from two or more filaments associated with each other to form a unitary structure. In one embodiment, the multifilament fiber is a non-bonded multifilament fiber. As used herein, "unbonded multifilament fiber" has its own ordinary and customary meaning and may comprise an assembly of two or more filaments that contact each other at least one point along their length but are not physically attached to each other. Non-limiting examples of unbonded multifilament fibers include yarns (filaments twisted about one another along their length) and tows (filaments not twisted about one another along their length).

The multifilament fibers can have a variety of configurations. For example, in some implementations, each multifilament fiber includes about 6 to 40 filaments. In one aspect, each multifilament fiber comprises between about 14 and 28 filaments. The increased surface area and voids present between the filaments of the multifilament fiber may be beneficial for improving tissue ingrowth within the scaffold (see, e.g., example 2).

The multifilament fibers can have a variety of sizes. For example, each multifilament fiber may have an average diameter of about 0.02mm to 0.2mm, about 0.05mm to 0.2mm, or about 0.15mm to 0.2 mm. In some implementations, each filament in a multifilament fiber has a diameter that is less than the fiber diameter of a monofilament fiber. For example, where the

knitted layers

802, 804 include a first type of fiber that is a multifilament fiber and a second type of fiber that is a monofilament fiber, the diameter of each filament in the multifilament fiber may be about 1/5 to 1/20 of the diameter of the monofilament fiber. In certain embodiments, each filament in a multifilament fiber may have a diameter of about 1/10 a of the diameter of the monofilament fiber.

The multifilament fibers may be formed from filaments formed of the same material or filaments of different materials. For example, in some implementations, a multifilament fiber can include a first filament of a first material and a second filament of a second material. In one embodiment, the second material degrades at a rate faster than the degradation rate of the first material. In this way, degradation of the second material may activate macrophages and thus promote accelerated attraction of macrophages and accelerate the inflammatory phase of healing, while not substantially affecting the variable stiffness profile of the scaffold over time after implantation. Activation of macrophages in turn can lead to an increase in myofibroblast population and neovascularization. In addition, degradation of the second material may promote tissue ingrowth within the scaffold. The first material may for example be at least one of the following: poly-L-lactic acid, copolymers of glycolide and L-lactide, copolymers of glycolic acid and lactic acid, poly (lactic acid) poly (lactic acid-glycolic acid copolymer), poly (lactic acid), polyglycolide, and copolymers of glycolide, caprolactone, trimethylene carbonate and lactide. Non-limiting examples of suitable first materials may be made from Polyglactin 910, Lactomer^TM9-1, 75:25 or 50:50 lactic acid/glycolic acid, Polygytone^TM6211. Or Caprosyn^TMAnd (4) forming. The second material may be, for example, a copolymer of glycolide and L-lactide, such as Vicryl Rapide^TM。

While the multifilament fibers may include various percentage ranges of the second filaments, in some implementations, the multifilament fibers may each include second filaments in the range of about 15% to 85% or in the range of about 25% to 45%. The second filaments may have various fiber diameters. For example, in some implementations, the second filament can have a fiber diameter of about 0.0005mm to 0.02 mm. In one embodiment, the second filaments have a fiber diameter of about 0.015 mm.

Monofilament fibers can have a variety of sizes. For example, the monofilaments may have a diameter of about 0.2mm to 0.35 mm. In some implementations, the individual diameters of the monofilament fibers can be less than the average diameter of the multifilament fibers. The average diameter (D) of the multifilament fibers can be calculated using the formula:

wherein:

w is the weight of the multifilament fiber (fiber bundle) per unit length

Number of filaments

ρ is the density of the fiber.

While the first type of fibers 808 and the second type of fibers 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 may be at least about 30 ℃ higher than the second glass transition temperature. In other exemplary embodiments, the first glass transition temperature may be at least about 45 ℃ higher than the second glass transition temperature. The difference in glass transition of the first type of fibers 808 and the second type of fibers 810 can also facilitate the secure attachment of the stent to the cartridge platform without adversely affecting the structural integrity of the stent.

As noted above, a portion of the stent is captured within the firing staples along with the tissue, and it is therefore desirable that the stent be formed from a suitable bioabsorbable material. Thus, the first type of fibers 808 and the second type of fibers 810 may each be formed from 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, copolymers of glycolide and L-lactide, copolymers of glycolic acid and lactic acid, poly (lactic acid) poly (lactic acid-glycolic acid copolymer), poly (lactic acid), polyglycolide, and copolymers of glycolide, caprolactone, trimethylene carbonate and lactide. For example, a first type of fiberVickers can be prepared from Polyglactin 910, Lactomer^TM9-1, 75:25 or 50:50 lactic acid/glycolic acid, Polygytone^TM6211. Or Caprosyn^TMAnd (4) forming. Non-limiting examples of suitable materials for the second type of fibers include at least one of: polydioxanone, copolymers of polydioxanone and polyglycolide, copolymers of lactide and polycaprolactone, copolymers of glycolide, dioxanone, and trimethylene carbonate, poly (trimethylene carbonate), polyhydroxyalkanoate, and polygluconate. For example, the second type of fiber may be made from 92:8 polydioxanone/polyglycolide, 25:75 lactide/polycaprolactone, Glycomer^TM631. Or Maxon^TMAnd (4) forming. In one embodiment, the first type of fibers is formed from Polyglactin 910 and the second type of fibers is formed from polydioxanone.

In some embodiments, the first type of fibers 808 may be coated with a bioabsorbable polymeric material. As such, the glass transition temperature of the first type of fibers 808 may be altered, for example, by increasing or decreasing the glass transition temperature as compared to the glass transition temperature of the matrix material of the first type of fibers, which may be desirable in certain circumstances for attaching the bracket to the cartridge platform. For example, lowering the glass transition temperature of the first type of fibers 808 can make the stent 800 more securely attached to a cartridge platform (such as cartridge platform 606 in fig. 6) and/or enhance the conformability of the stent 800 to the cartridge platform and maintain a suitable shape when cooled. Non-limiting examples of suitable coating materials include polydioxanone or 25:75 lactide/polycaprolactone.

While the knit layers 802, 804 can each have various knit patterns, in some implementations, as shown in fig. 8A-8C and 9, the knit layers 802, 804 can each have a Rachel knit pattern (e.g., as described in example 1 below). Those skilled in the art will appreciate that the knit layer of the stent may take the form of other warp knit patterns.

As shown in fig. 8A-8C and 9, the second type of fibers 810 may be interconnected with the first type of fibers 808 of the first and second layers of

knitting

802, 804 in a manner in which the first and second fibers are non-fixedly attached and slidably interconnected. Thus, in this illustrated embodiment, the first type of fibers 808 and the second type of fibers 810 can move relative to each other, thereby allowing movement and stretching in the x-direction (e.g., stretching) and the y-direction (e.g., compressing). In addition, the interconnection between the first type of fibers 808 and the second type of fibers 810 may at least partially affect the stiffness of the stent 800. For example, the tighter the interconnection, the stiffer the stent 800.

Further, as shown in fig. 8A-8C and 9, the first and second knit layers 802 and 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 by the first and second types of

fibers

808, 810. The size of the openings 812 of the second knitted layer 804 may be less than about 1/4 the width of the crowns of the staples (e.g., staples 406 in fig. 5). Thus, in some implementations, the crowns of the firing staples can span at least four openings 812 in the second layer of knitting 804. In one embodiment, the size of the opening 812 may be about 1/8 the width of the crown. While the crown of the staple can have a variety of widths, in some implementations, the width of the crown can be about 0.080 to 0.140 inches. In one embodiment, the crown has a width of about 0.12 inches.

The plurality of openings 812 in the first and second knit layers 802, 804 can have a variety of sizes. For example, the plurality of openings 812 in the second knitted layer 804 may have a diameter of about 0.002 inches to 0.1 inches. As used herein, the "diameter" of an opening is the maximum distance between any pair of vertices of the opening.

As discussed above and shown in fig. 8A-8C and 9, the stent 800 includes a support layer 806 positioned between the first and second knit layers 802, 804. The support layer 806 is non-fixedly attached to the first and second

knitted layers

802, 804. The support layer 806 can be configured such that when the stent 800 is attached to a cartridge platform (e.g., cartridge platform 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 platform. The support layer 806 is shown in fig. 8A-8C and 9 in order to contain only the second type of fibers 810 (which in this exemplary embodiment are monofilaments), while it is also contemplated herein that the support layer 806 may contain additional types of fibers, including, for example, the first type of fibers 808.

As shown, the fibers 810 of the support layer 806 are arranged within the support layer 806 to form upstanding (spaced) fibers 814 and a plurality of voids 816 therebetween. The upstanding fibers 814 are non-fixedly attached to each other. Further, the standing fibers 814 are non-fixedly and slidably interconnected to the fibers 808 of the first type 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 knit layers 802 and 804.

The upstanding fibers 814 are configured to bend under the force applied to the stent 800 (e.g., when sutured to tissue). The resiliency of the upstanding fibers 814 at least partially allows the scaffold to compress at various heights, thereby accommodating tissue (T) having tissue portions of different thicknesses. That is, regardless of the specific tissue thickness, the sum of the compressed height of the captured tissue and the scaffold within the firing staples can be maintained, and thus can be maintained equal to or at least substantially equal to the height of the firing staples. As such, at least in part, stent 800 may be configured to apply at least about 3g/mm to captured tissue²For at least a predetermined period of time (e.g., at least about 3 days).

In general, the material composition, height, and/or cross-sectional area of each upstanding fiber 814 at least partially controls its stiffness or ability to bend under compression, which in turn at least partially controls the compressibility of the stent 800. Thus, the upstanding fibers 814 can be configured to adjust the compressibility of the stent 800 to one or more desired values. For example, although the stand-up fibers 814 in fig. 8B-8C and 9 are the same material, in some implementations, the support layer 806 can include stand-up fibers of different materials having different stiffnesses. Alternatively or additionally, in some implementations, the support layer 806 can include standing fibers of different heights and/or cross-sectional areas. In one embodiment, the upstanding fibers 814 can have a high length to diameter ratio, such as a ratio of about 25:1 to 6: 1. In this way, the upstanding fibers 814 can further promote tissue ingrowth and cell integration within the implanted scaffold.

The amount of upstanding fibers 814 within a section of the support layer 806 may affect the compressibility of such section, thereby affecting the compressibility of the stent 800, among other things. In some cases, the standing fibers 814 may be strategically concentrated in certain sections of the support layer 806, for example, to provide greater column strength in such sections. In at least one instance, the standing fibers 814 can be concentrated in a section of the support layer 806 configured to receive the staples as they are fired. Alternatively, the standing fibers 814 can be concentrated in sections of the support layer 806 that do not receive staples as they are fired.

The ratio of voids 816 to upstanding fibers 814 can vary. In one implementation, the ratio may be in the range of at least about 3: 1. In other implementations, the ratio of voids 816 to upstanding fibers 814 can be in a range of at least about 5:1 or at least about 12: 1. Additionally, at least a portion of the voids 816 in the support layer 806 may each have a different size. In this way, variable void size throughout the cross-section of the stent 800 may promote extracellular remodeling. That is, the variable void size may facilitate revascularization and cell mobility within the stent 800 when the stent is implanted, thereby promoting both tissue and cell ingrowth. In addition, the variable void size may also facilitate extraction of byproducts and cellular waste from the implanted scaffold and, thus, from the implantation site.

In some embodiments, the stent 800 may further comprise a porous layer interconnected to the second knitted layer 804. As such, when the stent 800 is attached to a cartridge platform (such as cartridge platform 606 in fig. 6), the porous layer will be positioned between the cartridge platform and the second layer of knitting 804. In one embodiment, the porous layer is fused or bonded to the second knitted layer 804. The porous layer may be formed of a material having a glass transition temperature lower than the glass transition temperature of the

fibers

808, 810 of the stent 800. It is also contemplated herein that the porous layer may be formed from a material having a glass transition temperature equal to or higher than the glass transition temperature of at least one of the

fibers

808, 810 of the stent 800. The porous layer may have a thickness of less than about 0.003 inches. In one embodiment, the porous layer has a thickness of less than about 0.001 inches. The porous layer may also include pores having a diameter greater than about 0.0005 inches. For example, in some implementations, the size of the holes may vary from about 0.0005 inches to about 0.001 inches. Additionally, in some implementations, the pores may constitute 50% of the surface area of the layer.

The stents described herein, such as stent 800 in fig. 8A-8C and 9, may be fabricated using any suitable method. For example, in one embodiment, the method can include forming a first knit layer, forming a second knit layer, and interlacing a space with the first knit layer and the second knit layer. The first and second knitted fibers may comprise fibers of a first polymer. The first layer of knitting can be configured to mate with the cartridge deck. Interlacing the spacer fibers with the first and second knit layers can join the first and second knit layers together in a spaced parallel relationship. As used herein, "spaced apart parallel relationship" means that the first and second layers extend in planes that are remote from and substantially parallel to each other. The spacer fibers may be formed only of a second polymer different from the first polymer. The diameter of the first polymer fibers may be different from the diameter of the second polymer fibers. The spacer fibers may be integral with and extend between the first and second knit layers. The method may further include toughening (knitting) the first and second knit layers interwoven with the spacer fibers.

The interlacing of the spacer fibers with the first and second knit layers may form a support layer between the first and second knit layers. The forming of the first knit layer can include knitting the first polymeric fibers according to a predetermined pattern. The forming of the second knitted layer may include knitting the first polymer fibers according to a predetermined pattern. While these knit layers can each have various knit patterns, in some implementations, these knit layers can each have a Rachel knit pattern (e.g., as described in example 1 below). Those skilled in the art will appreciate that the knit layer of the stent may take the form of other warp knit patterns.

Fig. 12A shows another exemplary embodiment of a stent 1000. Except for the differences described in detail below, stent 1000 may be similar in construction to stent 800 (fig. 8A-8C and 9) and therefore not described in detail herein. In this embodiment, the stent 1000 includes a first knit layer 1002 having a first portion 1004 and a second portion 1006, each having an outer edge and an inner edge. The

inner edges

1004a, 1006a define a channel 1008 that extends along the longitudinal axis (L) of the stent 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 stent 1000. In particular, the channel 1008 does not extend through the second knit layer 1010. As such, the stent 1000 is configured to be capable of sufficient structural integrity to be effectively manipulated and attached to a cartridge platform, such as the cartridge platform 2014 in fig. 12B. In another embodiment, as shown in fig. 13, stent 3000 may have a fenestrated channel 3008. In use, as the cutting member is initially fired and advanced along the stent 1000, the cutting member cuts through the second layer of knitting 1010, thereby separating the stent 1000 into two pieces.

In addition, as shown in fig. 12A, the bracket 1000 includes a flange 1012 that is configured to mate with a recessed channel (such as the recessed channel 2016 of the cartridge platform 2014 in fig. 12B), as described further below. While fig. 12A shows the stent 1000 having a flange 1012 on one side of the stent 1000, there is an additional flange 1012 positioned on the opposite side of the stent 1000. Those skilled in the art will appreciate that the number and arrangement of the flanges 1012 are not limited to the number and arrangement shown in FIG. 12A. While the flange 1012 can be made from a variety of materials, in some implementations, as shown in figure 12A, the flange 1012 is an extension of the second knit layer 1010. In other embodiments, the flanges 1012 may be formed of different materials and formed in the same line or out of line with other components of the bracket 1000. Those skilled in the art will appreciate that the flange may be formed of the same or different material as the first and/or second knitted layers of the stent and may be attached thereto by any suitable method.

FIG. 12B illustrates another exemplary embodiment of a staple cartridge assembly 2000. The cartridge assembly 2000 may be similar to the cartridge assembly 600 (fig. 6), except for the differences described in detail below, and therefore, is not described in detail herein. Moreover, for simplicity, certain components of the cartridge assembly 2000 are not shown in FIG. 12B.

The staple cartridge assembly 2000 includes the carriage 1000 of fig. 12A attached to a cartridge deck 2014 having a recessed channel 2016. The bracket 1000 may be attached to the cartridge platform using any suitable method, as described in more detail below. As shown, the recessed channel 2016 is configured to receive the flange 1012 such that the flange 1012 can be attached to the side of the cartridge deck. In this way, the stent 1000 may be more securely attached to the cartridge platform 2014, thereby preventing the stent 1000 from undesired movement during use.

The stent may be applied to the cartridge deck using any suitable method to form a staple cartridge assembly. For example, in some embodiments, the method can include heating a cartridge platform and positioning a stent against a surface of the cartridge platform. The scaffold may comprise a first type of fibres and a second type of fibres, wherein the first type of fibres is predominantly present. As used herein, "predominantly present" when used to describe the amount of a particular fiber in a layer refers to an amount greater than 50% of the total amount of fibers in that layer. The first type of fiber may have a first glass transition temperature and the second type of fiber may have a second glass transition temperature that is lower than the first glass transition temperature. The cartridge platform can be heated to a temperature of at least the second glass transition temperature. The method can further include cooling the cartridge platform and the scaffold applied to the cartridge platform to a temperature below the second glass transition temperature.

The stent may include first and second knit layers each having first and second types of fibers and a support layer disposed between the first and second knit layers. In such a case, the positioning of the scaffold against the surface of the cartridge platform can include placing the first layer of knitting against the surface and applying a force to the scaffold such that the first layer of knitting bonds and conforms to the shape of the surface. The support layer may be formed from the second type of fibers.

The devices disclosed herein may be designed to be discarded after a single use, or they may be designed to be used multiple times. In either case, however, the device may be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the instrument is detachable, and any number of particular parts or components of the instrument may be selectively replaced or removed in any combination. After cleaning and/or replacement of particular components, the instrument may 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 the prosthetic device may be disassembled, cleaned/replaced, and reassembled using a variety of techniques. The use of such techniques and the resulting prosthetic devices are within the scope of the present application.

The present teachings may be further understood by reference to the following non-limiting examples.

Examples

Example 1: manufacture of stents

A sample was prepared having two knitted layers and a support layer disposed between the two knitted layers. The two knitted layers are each formed from Vicryl fibers (multifilament fibers of Vicryl) and the support layer is formed from Polydioxanone (PDS) fibers (monofilament fibers of PDS), the details of which are provided in table 1 below.

Table 1: vicryl and polydioxanone fiber information

Optical fiber	Fiber diameter (mil)	Ten (pound force)	Elongation (%)
				7-0PDS, dyed	3.18	0.67	38.28
2ply, 28 denier Vicryl, Natural	1.17	0.58	20.34

A 16 gauge double needle bar Raschel knitting machine warp knit sample having a six bar (GB) configuration was used. Each guide bar was individually controlled using a pattern chain, the pattern of which can be seen in table 2 below. PDS was used in the support layer and Vicryl was used for the knit layer.

Table 2: pattern chain

Samples of approximately 6.4 yards and 5 inches wide were prepared. The sample was scrubbed with isopropanol. The samples were placed on rollers, sealed in nitrogen purged foil bags, and kept under a nitrogen flow until further processing.

The samples were then toughened in approximately 5 inch by 5 inch sections using cycling conditions as described in table 3.

Table 3: circulation conditions

The toughened sample was then cut to produce a sample holder of approximately 5mm x 10 mm. One of the stent samples was examined by Optical Microscopy (OM) and SEM. Various OM images of the sample holder are shown in fig. 8A to 8C, and cross-sectional SEM images of the holder samples are shown in fig. 9.

Example 2: cellular ingrowth and limited inflammation

The sample scaffolds prepared in example 1 were subcutaneously implanted into rabbits injected with hematoxylin and eosin (H & E) for up to 90 days. Histopathological images of the implant stent removed on day 60 are shown in fig. 10A-10B, and the implant stent removed on day 90 is shown in fig. 11A-11B. The white ovals/circles shown in these images are fibers of the stent that are either vertically or slightly cut. As shown, the black box shows some portions of the scaffold where tissue ingrowth occurred during implantation. In addition, the arrows in fig. 10B and 11B point to the inflammatory area around the fibers, which indicates the inflammatory phase of healing.

Those skilled in the art will recognize additional features and advantages of the present invention in light of 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 its entirety or 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.

Claims

1. A staple cartridge assembly for use with a surgical stapling instrument, comprising:

a staple cartridge having a cartridge deck and a plurality of staples; and

a knitted elastically deformable, bioabsorbable scaffold attached to the cartridge platform and formed of at least three distinct zones, each zone having a different function, wherein the staples are deployable through the scaffold into tissue captured against the scaffold, and wherein the scaffold comprises:

a first knitted region configured to promote tissue ingrowth, wherein the first knitted region comprises first fibers made of a first bioabsorbable polymer and second fibers made of a second bioabsorbable polymer, wherein the fiber diameter of each first fiber is less than the fiber diameter of each second fiber;

a second knit region configured to conform to for attachment to the cartridge platform and comprising the first fibers and the second fibers of the first knit region; and

a spacer region formed from the second fiber, wherein the spacer region is disposed between the first and second knit regions and is configured to support the first and second knit regions, wherein the second fiber is non-fixedly and slidably interconnected to the first fiber of the first knit region and the first fiber of the second knit region,

wherein there are openings in the first and second knit regions and voids in the spacer regions, wherein the voids are larger than the openings.

2. The staple cartridge assembly of claim 1, wherein said first fibers have a fiber diameter of about 1/5-1/20 of the fiber diameter of said second fibers.

3. The staple cartridge assembly of claim 1, wherein said first fiber has a fiber diameter that is about 1/10 times greater than a fiber diameter of said second fiber.

4. The staple cartridge assembly of claim 1, wherein said second fibers extend from said first knit region to said second knit region such that said second fibers extend across said spacer regions, wherein at least a portion of said second fibers within said spacer regions are oriented substantially perpendicular to said first fibers of said first knit region and said first fibers of said second knit region.

5. The staple cartridge assembly of claim 1, wherein said first type of fibers are formed from at least one of: poly-L-lactic acid, copolymers of glycolide and L-lactide, copolymers of glycolic acid and lactic acid, poly (lactic acid-glycolic acid copolymer), poly (lactic acid), polyglycolide, and copolymers of glycolide, caprolactone, trimethylene carbonate and lactide.

6. The staple cartridge assembly of claim 1, wherein said second type of fibers are formed from at least one of: polydioxanone, copolymers of polydioxanone and polyglycolide, copolymers of lactide and polycaprolactone, copolymers of glycolide, dioxanone, and trimethylene carbonate, poly (trimethylene carbonate), polyhydroxyalkanoate, and polygluconate.

7. The staple cartridge assembly of claim 1, wherein said scaffold is configured to apply at least about 3g/mm to captured tissue when said scaffold is in a tissue deployed state²For at least 3 days.

8. A staple cartridge assembly for use with a surgical stapling instrument, comprising:

a staple cartridge having a cartridge deck and a plurality of staples; and

a first zone having a knit structure and configured to promote tissue ingrowth, wherein the first zone comprises first fibers made of a first bioabsorbable polymer; and

a second zone formed of second fibers made of a second bioabsorbable polymer and 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 the fiber diameter of each first fiber is less than the fiber diameter of each second fiber, and wherein there is an opening in the first zone and a void in the second zone, wherein the void is larger than the opening.

9. The staple cartridge assembly of claim 8, wherein said scaffold further comprises a third zone having a knit structure and configured to conform for attachment to said cartridge deck, said third zone comprising said first fibers, and wherein said second zone is located between said first zone and said third zone.

10. The staple cartridge assembly of claim 8, wherein said second fibers are non-fixedly and slidably interconnected to said first fibers of said third zone, and wherein said second fibers extend from said first zone to said third zone such that at least a portion of said second fibers are vertically oriented within said second zone.

11. The staple cartridge assembly of claim 10, wherein said scaffold is configured to apply at least about 3g/mm to captured tissue when said scaffold is in a tissue deployed state²For at least 3 days.

12. The staple cartridge assembly of claim 8, wherein said first fibers have a fiber diameter of about 1/5-1/20 of the fiber diameter of said second fibers.

13. The staple cartridge assembly of claim 8, wherein said first fiber has a fiber diameter that is about 1/10 times greater than a fiber diameter of said second fiber.

14. The staple cartridge assembly of claim 8, wherein said first type of fibers are formed from at least one of: poly-L-lactic acid, copolymers of glycolide and L-lactide, copolymers of glycolic acid and lactic acid, poly (lactic acid-glycolic acid copolymer), poly (lactic acid), polyglycolide, and copolymers of glycolide, caprolactone, trimethylene carbonate and lactide.

15. The staple cartridge assembly of claim 8, wherein said second type of fibers are formed from at least one of: polydioxanone, copolymers of polydioxanone and polyglycolide, copolymers of lactide and polycaprolactone, copolymers of glycolide, dioxanone, and trimethylene carbonate, poly (trimethylene carbonate), polyhydroxyalkanoate, and polygluconate.

16. A rack for use with a surgical staple cartridge, comprising:

a second knit region configured to conform to for attachment to a cartridge platform and comprising the first fibers and the second fibers of the first knit region; and