System and method for customizing crosslinking density in bioabsorbable materials

Abstract

The disclosed technology includes a bioabsorbable material configured to be delivered to tissue. The material includes a porous body comprising at least one polymer, which comprises a first zone having a first crosslinking density and a second zone having a second crosslinking density different from that of the first zone. At least the first and second zones form a compressive strength gradient along a portion of the porous body.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims priority under Section 119 of the United States Patent Act to U.S. Provisional Patent Application No. 63 / 522,660, filed on 22 June 2023, and to U.S. Non-Provisional Patent Application No. 18 / 484,988, filed on 11 October 2023, the entire contents of which are incorporated herein by reference.

[0002] (Field of Invention) The present invention relates, in general terms, to a system and method for embedding medical additives in bioabsorbable materials. [Background technology]

[0003] Surgical staplers are used in surgical procedures to close openings in tissues, blood vessels, conduits, shunts, or other objects or body parts related to a particular procedure. Openings may be naturally occurring, such as passages within blood vessels or viscera like the stomach, or they may be created by a surgeon during a surgical procedure, such as by forming a bypass or anastomosis by puncturing tissue or blood vessels, or by incising tissue during stapling.

[0004] Most staplers have a handle (some directly operated by the user, others via a robotic interface), and a slender shaft extends from the handle, with a pair of movable opposing jaws formed at one end, between which staples are held and formed. Staples are typically housed in a staple cartridge, which can hold multiple rows of staples and is often located within one of the two jaws for the release of staples to the surgical site. During use, the jaws are positioned so that the object to be stapled is placed between them, and when the jaws close and the device is activated, the staples are released and formed. Some staplers include a knife, which is configured to move between rows of staples in the staple cartridge, and between the stapled rows, to longitudinally incise and / or open the stapled tissue. [Overview of the Initiative] [Means for solving the problem]

[0005] According to an example of the present invention, a bioabsorbable material configured to be delivered to tissue is provided. The material comprises a porous body comprising at least one polymer having a first zone having a first crosslinking density and a second zone having a second crosslinking density different from that of the first zone. At least the first and second zones form a compressive strength gradient along a portion of the porous body.

[0006] According to an example of the present invention, a method for forming a bioabsorbable material is provided. This method may include the steps of: chemically reacting a polyol with an isocyanate to form a porous body; and adding a polymerizable compound to at least a portion of the porous body. The polymerizable compound may have crosslinkable units. The polymerizable compound may be configured to undergo crosslinking between crosslinkable units when exposed to a stimulus, thereby regulating the crosslinking density in the porous body. [Brief explanation of the drawing]

[0007] The present invention will be more fully understood by reading the following embodiments in conjunction with the accompanying drawings. [Figure 1] This is a perspective view of an exemplary embodiment of a conventional surgical staple fastening and cutting instrument. [Figure 2A] Figure 1 is a top view of a staple cartridge for use with surgical staple fastening and cutting instruments. [Figure 2B] Figure 2A is a side view of the staple cartridge. [Figure 3] Figure 2A is a side view of a staple in an unfired (pre-deployed) configuration, which may be placed inside the staple cartridge of the surgical cartridge assembly. [Figure 4] Figure 1 is a perspective view of the knife and launching bar ("E-beam") of a surgical staple fastening and cutting instrument. [Figure 5] Figure 1 is a perspective view of the wedge thread of the staple cartridge for a surgical staple fastening and cutting instrument. [Figure 6A] This is a longitudinal cross-sectional view of an exemplary surgical cartridge assembly having a compressible, non-fibrous auxiliary material attached to the top or deck surface of a staple cartridge. [Figure 6B] This is a longitudinal cross-sectional view of a surgical end effector having an anvil pivotably connected to an elongated channel, and a surgical cartridge assembly (Figure 6A) positioned within and connected to the elongated channel, showing the anvil in a closed position with no tissue between it and the auxiliary material. [Figure 7] Figure 7A is a schematic partial view showing the auxiliary material from Figures 6A-6B in its unfolded state. Figure 7B shows an enlarged portion of an exemplary auxiliary material having a porous structure. [Figure 8] This is a perspective view of an exemplary cartridge assembly. [Figure 9A] This is a perspective view of an exemplary surgical cartridge assembly in which a bioabsorbable material auxiliary is attached to the top or deck surface of the staple cartridge. [Figure 9B] FIG. 1 is a perspective view of an exemplary surgical cartridge assembly in which an auxiliary material of a bioabsorbable material is attached to the upper portion or the deck surface of a staple cartridge. [Figure 9C] FIG. 1 is a perspective view of an exemplary surgical cartridge assembly in which an auxiliary material of a bioabsorbable material is attached to the upper portion or the deck surface of a staple cartridge. [Figure 9D] FIG. 1 is a perspective view of an exemplary surgical cartridge assembly in which an auxiliary material of a bioabsorbable material is attached to the upper portion or the deck surface of a staple cartridge. [Figure 10A] FIG. 2 is a side view of an exemplary end effector having an auxiliary material of a bioabsorbable material in a delivery configuration. [Figure 10B] FIG. 3 is a side view of an exemplary end effector having an auxiliary material of a bioabsorbable material after firing and ejection from a cartridge. [Figure 11A] FIG. 4 is a top perspective view of an exemplary auxiliary material after use. [Figure 11B] FIG. 5 is a side view of an exemplary auxiliary material after use. [Figure 12] FIG. 6 is a flowchart showing an exemplary method of forming a surgical auxiliary material by spatial control of the mechanical properties of a bioabsorbable material. DETAILED DESCRIPTION

[0008] The following detailed description should be read with reference to the drawings, and like elements in different drawings are numbered the same. The drawings are not necessarily to scale and depict selected embodiments and are not intended to limit the scope of the invention. The detailed description is illustrative, not restrictive, and is intended to illustrate the principles of the invention. This specification enables those skilled in the art to make and use the invention and describes some embodiments, adaptations, variations, alternatives, and uses of the invention, including what is currently considered to be the best mode for carrying out the invention.

[0009] As used herein, the term "about" or "substantially" with respect to any numerical value or range indicates a reasonable dimensional tolerance that allows a component or collection to function for the intended purpose described herein. More specifically, "about" or "substantially" can refer to a range of values that are ±10% of the recited value. For example, "about 90%" can refer to a range of values from 81% to 99%.

[0010] As used herein, the term "polyurethane" refers to the polymer reaction product of an isocyanate and a polyol and is not limited to polymers containing only urethane bonds or polyurethane bonds. It is well understood by those skilled in the art that a polyurethane polymer may also contain bonds such as allophanate, carbodiimide, and other bonds described herein in addition to urethane bonds.

[0011] The expressions "reaction system", "reactive formulation", "reaction product", and "reactive mixture" are used interchangeably herein and all refer to combinations of reactive compounds used to produce the bioabsorbable materials according to the present disclosure.

[0012] The term "room temperature" refers to a temperature of about 20°C, which means it refers to a temperature range of 18°C to 25°C. Such temperatures include 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, and 25°C.

[0013] Unless otherwise specified, the "weight percent" of a component in a composition (expressed as % weight or weight %) refers to the weight of the component relative to the total weight of the composition in which it is present and is expressed as a percentage.

[0014] The "glass transition temperature" and "T ,

[0015] " referred to herein refer to the temperature at which a reversible transition occurs from a hard glassy state to a rubbery state.

[0015] Surgical staple fastening assemblies, as well as methods for manufacturing and using the same, are provided. Generally, a surgical staple fastening assembly may include a staple cartridge in which staples are disposed, and an auxiliary material configured to be releasably held on the staple cartridge. As discussed herein, the various auxiliary materials provided may be configured to compensate for changes in tissue properties, such as changes in tissue thickness, and / or to promote tissue endografting when the auxiliary material is stapled to the tissue. As discussed herein, the auxiliary material may include bioabsorbable materials such as foams.

[0016] Exemplary staple fastening assemblies, as described herein and shown in the drawings, may include various features to facilitate the application of surgical staples. However, those skilled in the art will understand that staple fastening assemblies may include only some of these features, and / or various other features known in the art. The staple fastening assemblies described herein are intended to represent specific exemplary examples only. Furthermore, while auxiliary materials are described in relation to surgical staple cartridge assemblies, auxiliary materials can be used in relation to the reloading of staples that are not cartridge bases or any type of surgical instrument.

[0017] Figure 1 shows an exemplary surgical stapling and cutting device 100 suitable for use with implantable auxiliary materials. The illustrated surgical stapling and cutting device 100 includes an end effector 106 having an anvil 102 pivotally connected to an elongated channel 104. As a result, the end effector 106 can move between an open position, as shown in Figure 1, and a closed position in which the anvil 102 is positioned adjacent to the elongated channel 104 and engages tissue between them. The end effector 106 can be mounted at its proximal end on an elongated shaft 108 that forms a mounting portion 110. When the end effector 106 is closed, or at least substantially closed (for example, when the anvil 102 moves from the open position in Figure 1 toward the elongated channel), the mounting portion 110 can present a sufficiently small cross-section suitable for inserting the end effector 106 through a trocar. Device 100 is configured to staple and cut tissue, but surgical devices configured to staple tissue but not cut it are also contemplated herein.

[0018] In various cases, the end effector 106 can be operated by a handle 112 connected to an elongated shaft 108. The handle 112 includes a user control unit such as a rotary knob 114 that rotates the elongated shaft 108 and the end effector 106 around the longitudinal axis (Ls) of the elongated shaft 108, and an articulated axis (T) substantially crossing the longitudinal axis (Ls) of the elongated shaft 108. A The system may include an articulation control unit 115 that can articulate the end effector 106 around the pistol grip 118. Further control units may include a closing trigger 116 that can pivot relative to the pistol grip 118 to close the end effector 106. For example, when the closing trigger 116 is clamped, a closing release button 120 is presented on the outside of the handle 112, and pressing the closing release button 120 releases the clamp on the closing trigger 116 and opens the end effector 106. The handle 112 may also take the form of an interface for connection to a surgical robot.

[0019] In some examples, the firing trigger 122 can pivot relative to the closing trigger 116, thereby allowing the end effector 106 to simultaneously cut and staple the tissue clamped inside it. The firing trigger 122 may be powered, require user force to engage, or be any combination of these. A manual firing release lever 126 allows the firing system to be retracted before completing its full movement for firing, if desired, and further allows a surgeon or other clinician to retract the firing system if it becomes immobile and / or malfunctions.

[0020] Further details relating to the surgical stapling and cutting device 100 and other surgical stapling and cutting devices suitable for use with the present disclosure are described, for example, in U.S. Patent No. 9,332,984 and U.S. Patent Application Publication No. 2009 / 0090763, which are incorporated herein by reference in their entirety. Furthermore, the surgical stapling and cutting device does not need to include a handle and instead may have a housing configured to be coupled to a surgical robot, as described, for example, in U.S. Patent Application Publication No. 2019 / 0059889, which are incorporated herein by reference in their entirety.

[0021] As further shown in Figure 1, the staple cartridge 200 can be used with the apparatus 100. During use, the staple cartridge 200 is positioned and connected within the elongated channel 104. The staple cartridge 200 can have various configurations, but in this illustrated example, the staple cartridge 200 shown in detail in Figures 2A-2B has a proximal end 202a and a distal end 202b, with the longitudinal axis (LC) of the cartridge extending between the proximal end 202a and the distal end 202b. As a result, when the staple cartridge 200 is inserted into the elongated channel 104 (Figure 1), the longitudinal axis (LC) is substantially or nearly parallel to the longitudinal axis (LS) of the elongated shaft 108. Furthermore, the staple cartridge 200 includes a longitudinal slot 210 defined by two opposing walls 210a, 210b and configured to receive at least a portion of a launching member of a launching assembly, such as the launching assembly 400 in Figure 4, as will be discussed further below. As shown, the longitudinal slot 210 extends from the proximal end 202a to the distal end 202b of the staple cartridge 200. It is also intended herein that in other examples the longitudinal slot 210 may be omitted.

[0022] The illustrated staple cartridge 200 includes defined staple cavities 212, 214, each configured to removably accommodate at least a portion of staples (not shown). The number, shape, and position of the staple cavities can vary and depend at least on the size and shape (e.g., mouth-like shape) of the staples to be removably placed inside. In this illustrated example, the staple cavities are arranged in two sets of three longitudinal rows, with the staple cavities 212 of the first set located on the first side of the longitudinal slot 210, and the staple cavities 214 of the second set located on the second side of the longitudinal slot 210. For each side of the longitudinal slot 210, and therefore for each set of rows, the first longitudinal row of staple cavities 212a, 214a extends along the longitudinal slot 210, the second row of staple cavities 212b, 214b extends along the first row of staple cavities 212a, 214a, and the third row of staple cavities 212c, 214c extends along the second row of staple cavities 212b, 214b. Each row may be substantially parallel, and the staple cavities constituting the row may be oriented substantially parallel to the longitudinal slot 210. As shown in Figure 2A, each staple cavity 212, 214 may include a maximum length SL of about 0.122 inches to about 0.124 inches and a maximum width SW of about 0.023 inches to about 0.027 inches. Furthermore, at least the centers of the two adjacent cavities 212 and 214 are separated by approximately 0.158 inches.

[0023] The staples, which are releasably stored within the staple cavities 212 and 214, can have various configurations. An exemplary staple 300, which can be releasably stored in each of the staple cavities 212 and 214, is shown in its un-launched (pre-deployed, unformed) configuration in Figure 3. The illustrated staple 300 includes a crown (base) 302 and two legs 304 extending from each end of the crown 302. In this example, the crown 302 extends linearly, and the staple legs 304 have the same unformed height. Furthermore, before the staple 300 is deployed, the staple crown 302 may be supported by a staple driver positioned within the staple cartridge 200, and at the same time, the staple legs 304 may be at least partially housed within the staple cavities 212 and 214. Furthermore, when the staple 300 is in the un-launched position, the staple legs 304 may extend beyond an upper surface such as the upper surface 206 of the staple cartridge 200. In certain cases, as shown in Figure 3, the tip 306 of the staple leg 304 may be pointed and sharp so as to be able to cut and penetrate tissue.

[0024] During use, the staple 300 can deform from an unfired position to a firing position so that the staple legs 304 move through the staple cavities 212, 214, penetrate the tissue positioned between the anvil 102 and the staple cartridge 200, and come into contact with the anvil 102. As the staple legs 304 deform relative to the anvil 102, the legs 304 of each staple 300 can capture a portion of the tissue within each staple 300 and apply compressive force to the tissue. Furthermore, the legs 304 of each staple 300 can deform downward toward the crown 302 of the staple 300 to form a staple capture region into which tissue can be captured. In various cases, the staple capture region may be defined between the inner surface of the deformed leg and the inner surface of the crown of the staple. The size of the staple capture region may depend on several factors, such as the length of the leg, the diameter of the leg, the width of the crown, and / or the degree of leg deformation.

[0025] In some examples, all staples placed within the staple cartridge 200 may have the same unfired (pre-deployed, unformed) configuration. In other examples, the staples may include at least two groups of staples, each having a different unfired (pre-deployed, unformed) configuration, such as differing in height and / or shape from one another.

[0026] Referring again to Figures 2A and 2B, the staple cartridge 200 extends from the top or deck surface 206 to the bottom surface 208, with the top surface 206 configured as the surface facing the tissue and the bottom surface 208 configured as the surface facing the channel. As a result, as shown in Figure 1, when the staple cartridge 200 is inserted into the elongated channel 104, the top surface 206 faces the anvil 102 and the bottom surface 208 (which is obscured) faces the elongated channel 104.

[0027] Referring to Figures 4 and 5, a launch assembly, such as the launch assembly 400, can be used in conjunction with a surgical stapling and cutting device, such as the device 100 in Figure 1. The launch assembly 400 may be configured to advance a wedge thread 500, which has a wedge 502 configured to deploy staples from a staple cartridge 200, into tissue trapped between an anvil, such as the anvil 102 in Figure 1, and a staple cartridge, such as the staple cartridge 200 in Figure 1. Furthermore, an E-shaped beam section 402 located in the distal portion of the launch assembly 400 can launch staples from the staple cartridge. During launch, the E-shaped beam 402 can also pivot the anvil toward the staple cartridge, and thus move the end effector from an open position to a closed position. The illustrated E-shaped beam 402 includes a pair of upper pins 404, a pair of intermediate pins 406 which may follow a portion 504 of the wedge thread 500, and a lower pin or foot 408. The E-shaped beam 402 may also include a sharp cutting edge 410 configured to cut captured tissue as the firing assembly 400 advances distally, and thus toward the distal end of the staple cartridge. In addition, integrally formed, proximal projecting upper guides 412 and intermediate guides 414, flanking each vertical end of the cutting edge 410, may further define a tissue staging area 416 to assist in guiding tissue to the sharp cutting edge 410 before cutting the tissue. The intermediate guides 414 may also function to engage with and fire staples in the staple cartridge by abutting a stepped central member 506 of the wedge thread 500, which results in staple formation by the end effector 106.

[0028] During use, the anvil 102 in Figure 1 moves to the closed position by pressing down the closing trigger in Figure 1, allowing the E-shaped beam 402 in Figure 4 to advance. The anvil 102 can position the tissue against at least the upper surface 206 of the staple cartridge 200 in Figures 2A-2B. Once the anvil is properly positioned, the staples 300 in Figure 3, which are positioned within the staple cartridge, can be deployed.

[0029] To deploy staples from the staple cartridge, as described above, the thread 500 in Figure 5 can be moved from the proximal end to the distal end of the cartridge body, and therefore from the proximal end to the distal end of the staple cartridge. As the firing assembly 400 in Figure 4 advances, the thread can contact the staple driver in the staple cartridge and lift the staple driver upward within the staple cavities 212, 214. In at least one example, the thread and staple driver may each include one or more inclined or beveled surfaces, which can work together to move the staple driver upward from its unfired position. Once the staple driver is lifted upward within its respective staple cavity, the staple advances upward, exiting the staple cavity and penetrating into the tissue. In various cases, the thread may move several staples upward simultaneously as part of the firing sequence.

[0030] As described above, the stapling device can be used in combination with a compressible auxiliary material. Although such auxiliary materials are shown and described below, those skilled in the art will understand that the auxiliary materials disclosed herein can be used with other surgical instruments and do not need to be connected to a staple cartridge as described. Furthermore, those skilled in the art will understand that the staple cartridge does not need to be replaceable.

[0031] As mentioned above, with some surgical staplers, surgeons are often required to select the appropriate staple with the appropriate staple height for the tissue being stapled. For example, surgeons use tall staples for thick tissue and short staples for thin tissue. However, in some situations, the stapled tissue does not have a consistent thickness, and therefore the staple cannot achieve the desired post-launch configuration for all parts of the stapled tissue (e.g., parts of thick tissue and parts of thin tissue). If staples of the same or substantially higher height are used due to the inconsistent thickness of the tissue, undesirable leakage and / or tearing of the tissue may occur at the staple site, especially if the staple site is exposed to internal pressure at and / or along the row of staples.

[0032] Therefore, to avoid the need to consider staple height when stapling tissue during surgery, various examples of auxiliary materials are provided that can be configured to compensate for the varying thicknesses of tissue captured within the fired (deployed) staples. That is, the auxiliary materials described herein can also be used in combination with the auxiliary material to provide sufficient tissue compression within and between fired staples, while enabling the use of a set of staples of the same or similar height when stapling tissue of varying thicknesses (e.g., from thin to thick tissue). Thus, the auxiliary materials described herein can maintain suitable compression for thin or thick tissue being stapled, thereby minimizing leakage and / or tearing of tissue at the staple site. In addition, the exemplary auxiliary materials described herein may be configured to be absorbed into the body over a period of 100 to 300 days, depending on the implantation site and the health of the tissue.

[0033] Alternatively or in addition, the implantable material may be configured to promote tissue endografting. In various cases, it is desirable to promote tissue endografting into the implantable material in order to promote the healing of the tissue being treated (e.g., stapled and / or incised tissue) and / or to accelerate the patient's recovery. More specifically, tissue endografting into the implantable material may reduce the incidence, severity, and / or duration of inflammation at the surgical site. Tissue endografting into and / or around the implantable material may, for example, control the spread of infection at the surgical site. For example, endografting of blood vessels, particularly leukocytes, into and / or around the implantable material may combat infection in and around the implantable material and adjacent tissue. Tissue endografting may also facilitate the acceptance of foreign bodies (e.g., implantable materials and staples) by the patient's body and reduce the likelihood of the patient's body rejecting foreign bodies. Rejection of foreign bodies can lead to infection and / or inflammation at the surgical site.

[0034] Generally, the auxiliary materials provided herein are designed and positioned on top of a staple cartridge, such as a staple cartridge 200. When a staple is fired (deployed) from the cartridge, the staple penetrates the auxiliary material and enters the tissue. When the legs of the staples deform upon contact with an anvil positioned on the opposite side of the staple cartridge, the deformed legs capture a portion of the auxiliary material and a portion of the tissue within each staple. That is, when a staple is fired into the tissue, at least a portion of the auxiliary material is positioned between the tissue and the fired staple. While the auxiliary materials described herein may be configured to be attached to a staple cartridge, it is also intended herein that the auxiliary materials may be configured to mate with components of other instruments, such as an anvil for a surgical stapler. Those skilled in the art will understand that the auxiliary materials provided herein may be used for reloading staples that are not replaceable cartridges or cartridge-based.

[0035] In various embodiments, the auxiliary materials or bioabsorbable materials disclosed herein may consist of absorbent polymers. In certain embodiments, the auxiliary materials may consist of foams, films, fibrous fabrics, fibrous nonwoven polyurethanes, polyesters, polycarbonates, polyorthoesters, polyanhydrides, polyesteramides, polyoxaesters, polyphosphazenes, polyphosphoesters, polyether urethanes, polyester urethanes, polyester ureas, and / or polysaccharides. In other embodiments, the auxiliary materials may be copolymers including, for example, PGA (polyglycolic acid), PGA / PCL (poly(glycolic acid-co-caprolactone)), PLA / PCL (poly(lactic acid-co-polycaprolactone)), PLLA / PCL, PGA / TMC (poly(glycolic acid-co-trimethylene carbonate)), PDS, PEPBO, and the like. In various embodiments, the auxiliary materials may include, for example, organic materials such as carboxymethylcellulose, sodium alginate, hyaluronic acid, and / or oxidized regenerated cellulose. In various embodiments, the auxiliary material has a durohardness in the range of 3 to 7 Shore A (30 to 50 Shore 00) with a maximum stiffness of 15 Shore A (65 Shore 00). In certain embodiments, the auxiliary material can be subjected to, for example, 40% compression under a load of 3 lbf, 60% compression under a load of 6 lbf, and / or 80% compression under a load of 20 lbf. In certain embodiments, one or more gases such as air, nitrogen, carbon dioxide, and / or oxygen can be bubbled through and / or contained within the auxiliary material.

[0036] How to staple tissue Figures 6A and 6B show exemplary examples of a staple fastening assembly 600 including a staple cartridge 200 and an auxiliary material 604. For simplification, the auxiliary material 604 is shown in its entirety in Figures 6A and 6B, and various configurations of the auxiliary material are described in more detail below. As shown, the auxiliary material 604 is positioned relative to the staple cartridge 200. Although partially obscured in Figures 6A and 6B, the staple cartridge 200 includes staples 300 configured to unfold within the structure. The staples 300 can have any preferred unformed (pre-unfolded) height.

[0037] In the illustrated examples, the auxiliary material 604 may be fitted to at least a portion of the top surface or deck surface 206 of the staple cartridge 602. In some examples, the top surface 206 of the staple cartridge 200 may include one or more surface features that engage with the auxiliary material 604 and / or prevent premature release of the auxiliary material 604 from the staple cartridge 200. Exemplary surface features are described further below and are described in U.S. Patent No. 10,052,104, which is incorporated herein by reference in its entirety.

[0038] Figure 6B shows a staple fastening assembly 600 positioned within and connected to an elongated channel 610 of a surgical end effector 106. Anvil 102 is pivotally connected to the elongated channel 610 and is therefore movable between an open position and a closed position relative to the elongated channel 610, and thus to the staple cartridge 200. Anvil 102 is shown in the closed position in Figure 6B, and the interstitial gap T created between the staple cartridge 602 and anvil 612 is visible. G1 This shows that. More specifically, the interstitial space T G1The intercellular gap T is defined by the distance between the microstructure compression surface 102a of the anvil 102 (e.g., the microstructure engagement surface between staple-forming pockets in the anvil) and the microstructure contact surface 604a of the auxiliary material 604. In this illustrated example, both the microstructure compression surface 102a of the anvil 102 and the microstructure contact surface 604a of the auxiliary material 604 are planar or substantially planar (e.g., planar within manufacturing tolerances). As a result, when the anvil 102 is in the closed position, the intercellular gap T is as shown in Figure 6B. G1 When no tissue is present within it, it is generally uniform (for example, nominally identical within manufacturing tolerances). In other words, the inter-tissue gap T G1 The interstitial gap T is approximately constant across the end effector 106 (e.g., in the y-direction) (e.g., constant within manufacturing tolerances). In other examples, the microstructure compression surface of the anvil includes a stepped surface with longitudinal steps between adjacent longitudinal portions, thus creating a stepped profile (e.g., in the y-direction). In such examples, the interstitial gap T G1 It can fluctuate.

[0039] The auxiliary material 604 is compressible and can be compressed to various heights to compensate for different tissue thicknesses captured within the deployed staple. The auxiliary material 604 has an uncompressed (undeformed) or pre-deployment height and is configured to deform to one of several compressed (deformed) or deployed heights. For example, the auxiliary material 604 may have an uncompressed height that is higher than the post-launch height of the staple 300 placed in the staple cartridge 200 (e.g., the height (H) of the launched staple 300a in Figure 7A). That is, the auxiliary material 604 may have an undeformed state in which the maximum height of the auxiliary material 604 is higher than the maximum height of the launched staple (e.g., the staple in the formed configuration).

[0040] When a surgical stapling and cutting device, such as device 100 of FIG. 1, is oriented towards the surgical site during use, the anvil 102 is positioned adjacent to a first side of the tissue and the stapling assembly 600 is positioned adjacent to a second side of the tissue such that the tissue is positioned between the anvil 102 and the stapling assembly 600 (e.g., the tissue can be positioned relative to the tissue contact surface 604a of the bolster 604). When the tissue is positioned between the anvil 102 and the stapling assembly 600, the surgical stapler is actuated, for example as described above, thereby clamping the tissue between the anvil 102 and the stapling assembly 600 (e.g., between the tissue compression surface 102a of the anvil 102 and the tissue contact surface 604a of the bolster 604) and deploying staples from the cartridge through the bolster into the tissue to staple and attach the bolster to the tissue.

[0041] As shown in FIG. 7A, when the staple 300 is fired, a portion of the tissue (T) and the bolster 604 is captured by the fired (formed) staple 300a. The fired staple 300a defines a capture region therein, as described above, for accommodating the captured bolster 604 and tissue (T). The capture region defined by the fired staple 300a is at least partially limited by the height (H) of the fired staple 300a.

[0042] Referring to FIG. 7B, the bolster 604 can have holes 632 having a median pore size of, for example, about 0.022 mm 3 such as about 0.025 mm 3 to about 0.300 mm 3 In some examples, the bolster 604 can have one or more struts 634 between the holes 632 that provide support and strength to the bolster 604. Specifically, the bolster 604 can include a plurality of struts 634 having a median strut thickness ST of about 0.025 mm to about 0.300 mm, such as about 0.08 mm.

[0043] Figure 8 shows a perspective view of a staple cartridge assembly 600 having an auxiliary material 604 and a staple cartridge 200. The auxiliary material 604 has a tissue contact surface 604a, a proximal end 604c, and a distal end 604b. The auxiliary material 604 may include a slot / slit 808 that separates or partially separates two parallel portions of the auxiliary material 604. In one example, the auxiliary material 604 may include a slot 808 that separates two parallel portions of the auxiliary material 604, while in another example, the auxiliary material 604 may include a slit 808 that separates two parallel portions of the auxiliary material 604, and one or more bridges (e.g., five bridges) 802 that connect the two parallel portions of the auxiliary material 604. At least one bridge has a longitudinal length of about 0.035 inches to about 0.046 inches. The auxiliary material 604 has a length L of approximately 40 mm to approximately 80 mm, such as approximately 60 mm to approximately 65 mm, approximately 66.04 mm to approximately 66.3 mm, approximately 45 mm to approximately 55 mm, or approximately 51.12 mm to approximately 51.38 mm. The auxiliary material 604 has a width W of approximately 8 mm to approximately 12 mm, such as approximately 9.75 mm to approximately 10.25 mm or approximately 10.025 mm to approximately 10.035 mm. The auxiliary material 604 may also have a thickness or height TH of approximately 2.5 mm to approximately 3.5 mm, such as approximately 2.85 mm to approximately 3.15 mm, or approximately 2.95 mm to approximately 3.05 mm.

[0044] Cartridge 200 has a height CH of approximately 6.3 mm to approximately 8.1 mm, a width CW of approximately 8.9 mm to approximately 14 mm, and a length CL of approximately 80 mm to approximately 90 mm, for example, approximately 86.7 mm.

[0045] The staple cartridge 200 may include one or more raised ledges 804 along one or more sides of the auxiliary material 604 to help align the auxiliary material 604 on the deck of the staple cartridge 200. Although not shown in Figure 8, the staple cartridge 200 may also include an adhesive or buttress adhesive material for attaching the auxiliary material 604. The auxiliary material 604 may be attached to the cartridge 200 using about 100 mg to about 120 mg of the adhesive or buttress adhesive material.

[0046] Spatial control of mechanical properties by selective crosslinking density As described above, the end effector 106 (shown in Figure 1), including the cartridge 200 and the auxiliary material 604, is closed or substantially closed for insertion into the delivery site through the trocar. During delivery, the surgical auxiliary material 604 must have mechanical properties such that the material is sufficiently compressible, but must also have increased strength to hold staples, sutures, and screws in place at the delivery site. The surgical auxiliary material 604 can be modified for specific purposes before, during, and after surgical procedures, and may have one or more of the following properties that modify its mechanical properties. In particular, the auxiliary material 604 described may have selective crosslinking density control in vivo and may also have specific compressibility when attached to the cartridge outside the body.

[0047] Referring to Figures 9A and 9B, exemplary staple cartridge assemblies 900a, 900b having spatial control of mechanical properties include an auxiliary material 604 having two or more zones, such as a first zone 636 and a second zone 638. In some examples, the first zone 636 and the second zone 638 may be separate. The first zone 636 of the porous material 634 contains a first crosslinking density, while the second zone 638 has a second crosslinking density different from that of the first zone 636. As shown in staple cartridge assembly 900a, the second zone 638 is along the longitudinal axis L of the porous material 634. p They can be positioned approximately in the center along the longitudinal axis. Another orientation of spatial control of the cartridge assembly 900b is provided in Figure 9B, where two or more second zones 638 are positioned along the longitudinal axis and provide a gradient of bridging density in the lateral direction. As shown in Figure 9B, the second zones 638 can be positioned in the center along each half of the auxiliary material 604. In some examples, the spatial control shown in Figure 9B may provide optional slots / slits 808 that separate or partially separate two parallel portions of the auxiliary material 604, as shown in Figure 8.

[0048] As those skilled in the art will understand, such spatial control may be more optimal for tissue endoplasmosis or hemostatic behavior. Furthermore, the gradient may also have a composition with a fluctuating bioabsorption profile. A short-term absorption profile may be preferred to address hemostasis, while a long-term absorption profile can address better tissue healing without leakage.

[0049] Figures 9C and 9D provide exemplary staple cartridge assemblies 900c, 900d having spatial control of mechanical properties, and include an auxiliary material 604 having a first zone 636 and a second zone 638 located at substantially opposite ends of the auxiliary material 604, such as the proximal end 604c and the distal end 604b. In some embodiments, the second zone 638 at the proximal end 604c and the distal end 604b of the auxiliary material 604 may be substantially equal in length, as shown in Figure 9C. Alternatively, the length of the second zone 638 may be substantially greater at the distal end 604b of the auxiliary material 604, which may be desirable to adjust the crosslinking density where compression between the anvil and the cartridge 200 begins. Although not depicted, orientations in which the length of the second zone is substantially greater at the proximal end 604c of the auxiliary material 604 are also conceivable. In some examples, the spatial control shown in Figures 9C and 9D may provide optional slots / slits 808 that separate or partially separate the two parallel portions of the auxiliary material 604, as shown in Figure 8.

[0050] In some embodiments, an exemplary staple cartridge assembly having spatial control of mechanical properties may include an auxiliary material 604 having a first zone 636 and a second zone 638, wherein the second zone 638 is located on at least a portion of one side of the first zone 636. For example, the second zone 638 may coat at least one side, two sides, or all sides of the first zone 636. The coating may be resistant or substantially resistant to absorption at a specific pH, such as acidic conditions (pH < 7), so that the coating can be used in the stomach or tissues near the stomach. In other examples, the coating may delay the absorption time over a given time frame, preventing the bulk material of the auxiliary material from coming into contact with the fluid.

[0051] The auxiliary material 604 has a porous body 634 made of at least one polymer that can be selectively crosslinked via a photocurable network, monomer incorporation, stimulus-responsive functional groups, etc. The polymer may include polyurethane, polyester, polycarbonate, polyorthoester, polyanhydride, polyesteramide, and / or polyoxaester.

[0052] To achieve control of the crosslinking density, the polymer of the porous body 634 may have a polymerizable compound having a functional group that acts as a crosslinking unit, or may be mixed with such compound.

[0053] In some embodiments, the polymerizable compound is a chain extender that does not contribute to crosslinking. The chain extender may be incorporated into the monomer backbone of the polymer or as a pendant group. In some examples, the chain extender is a carbon-carbon system and has a double bond incorporated into the polymer backbone. In a non-limiting example, fumaric acid may be added during the condensation reaction of the polymer backbone of a porous material. When a photoinitiator is added, the fumaric acid in the polymer backbone provides crosslinking sites that are specifically controlled by lithography via photocurable sites. Furthermore, dimethyl fumarate can be selectively generated from the polymer backbone during the degradation of porous materials in the body, such as after surgical procedures. Dimethyl fumarate is a known Nrf2 activator that can be used to secondarily treat inflammation and prevent nerve damage.

[0054] In another example, a chain extender replaces one or more functional groups on the polymer backbone to reduce crosslinking. For example, in a polyurethane polymer backbone, a chain extender such as an acrylate or methacrylate can replace one of the hydroxyl groups from the polyol. The chain extender may be fumaric acid, succinic acid, maleic acid, and / or a combination thereof.

[0055] Returning to Figures 9A-9D, the polymerizable compound is added to either the first zone 636 or the second zone 638 only, so that the porous body 643 has different crosslinking densities around the central row of staples, or around the staple pockets and between the rows of staples. As those skilled in the art will understand, by utilizing a lower crosslinking density in the central row, where the pressure is lowest compared to the first and third rows, less force is required to launch the staples while maintaining the necessary compressive properties throughout the entire staple line.

[0056] Alternatively, polymerizable compounds can be added to both the first zone 636 and the second zone 638 at different concentrations. For example, a plasticizer (e.g., polyethylene glycol 200 (PEG-200)) may be included as a separate chemical additive or as part of the chemical backbone within the polymer. In another embodiment, polymerizable compounds having different functional groups and crosslinking densities can be added to either the first zone 636 or the second zone 638. In some embodiments, polymerizable compounds can be added before, during, or after the formation of the porous body.

[0057] In some embodiments, the change in crosslink density between the first zone 636 and the second zone 638 forms a gradient of compressive strength along a portion of the porous body 634. Generally, the auxiliary material 604 may have compressive strengths of about 30 kPa to about 70 kPa, such as about 30 kPa to about 60 kPa (e.g., about 42 kPa), about 30 kPa to about 50 kPa, and about 32.5 kPa to about 37.5 kPa. In some embodiments, the auxiliary material 604 may have compressive strengths of about 30 kPa to about 70 kPa in the first zone and about 15 to about 50 kPa in the second zone. To test the compressive strength, the auxiliary material 604 was placed in a humid, warm environment at about 37°C, compressed to a first height (e.g., about 1.75 mm), then compressed to a second height lower than the first height, and then released back to the first height when the compressive strength of the auxiliary material was measured.

[0058] In some cases, the auxiliary material 604 may have a tensile strength of approximately 30 kPa to 90 kPa, such as approximately 45 kPa to 85 kPa or approximately 55 kPa to 75 kPa. In some cases, the auxiliary material 604 may have a tensile strength of approximately 110 kPa to 150 kPa. Specifically, the tensile strength of the auxiliary material 604 may be measured after immersion in water at a temperature of approximately 37°C for less than one minute, followed by a tensile strength test.

[0059] In some embodiments, the polymerizable compound is a crosslinking monomer added to a polymer backbone that is particularly under-cured and retains reaction sites within a network. Additional crosslinking monomers can be deposited on or inside a porous body at patterned locations, or applied in other ways, to locally increase mechanical properties. In one non-limiting example, a polymer backbone having isocyanate functional groups, a polyol crosslinking monomer can be added to increase crosslinking at specific addition locations, for example, along only one of the first zone 636 or the second zone 638, as shown in Figures 9A and 9B. Monofunctional alcohols act as capping agents for isocyanate functional groups, so monofunctional alcohols can be added to zones intended to maintain crosslinking density. Crosslinking monomers may be arylboronic acids, styrylpyrene, styrene, and combinations thereof.

[0060] In some embodiments, direct crosslinking monomer addition can be carried out by any suitable technique, including but not limited to inkjet printing, direct deposition, thermal spraying, cold dynamic spraying, cold spraying, electrospraying, ultrasonic spray coating, dip coating, screen printing, and spin coating.

[0061] In yet another embodiment, the polymerizable compound is a stimulus-responsive functional group that can be reversibly crosslinked upon exposure to one or more of the following: heat, light, ultrasound, pH, counterion exchange, and combinations thereof. Examples of stimulus-responsive functional groups include o-nitrobenzyl, coumarin, anthracene, disulfide, diselenide, and Diels-alder (diene and dienophile). The stimulus-responsive functional group can enable a transition in crosslinking density from linear to complex structures such as star, cyclic, or hyperbranched. Stimulus-responsive functional groups may include vinyl acetate, acrylonitrile, vinylidene dichloride, isoprene, butadiene, chloroprene, and / or combinations thereof.

[0062] In any of the embodiments disclosed herein, polymerizable compounds can be used to adjust the crosslink density (and the mechanical properties of the porous body) over a predetermined time frame. For example, the change in crosslink density may occur over several seconds or minutes such that the porous body is easily compressible upon delivery, the end effector is easily inserted through the trocar, and after an induction period has elapsed, the mechanical strength of the porous body increases in a particular zone (e.g., zone 636 in the first zone of Figure 9A) as a function of spatial arrangement.

[0063] Figure 10A is a side view of the end effector 106 in a delivery configuration in which the auxiliary material 604 is compressible between the anvil 102 and the cartridge 200. As shown, the end effector 106 may include a staple cartridge 200 and an auxiliary material 604 containing a bioabsorbable material. In certain embodiments, the auxiliary material 604 is releasedly held on the cartridge 200. When the end effector 106 closes around the tissue T, the auxiliary material 604 can be compressed from the thickness of the uncompressed auxiliary material UT to the thickness of the compressed auxiliary material CT, depending on the variation in tissue thickness.

[0064] Figure 10B is a side view of the end effector 106 after firing of the staple 300, where the auxiliary material 604 is no longer compressed between the anvil 102 and the cartridge 200. As shown, the auxiliary material 604 is released from the cartridge 200 after firing. The auxiliary material 604 is shown to maintain the thickness CT of the compressed auxiliary material and the thickness UT of the uncompressed auxiliary material from before firing in Figure 10A. In some embodiments, the auxiliary material 604 may undergo a change in crosslink density before firing of the staple so that the auxiliary material height PH and the compressed portion CT are maintained after firing and release of the auxiliary material 604 and tissue T. In other embodiments, the auxiliary material 604 may undergo a change in crosslink density after a predetermined time frame, as described above. In such examples, the auxiliary material height PH and the compressed portion CT may expand or contract depending on the staple height and tissue thickness. As will be understood by those skilled in the art, a change in the crosslink density of the auxiliary material 604 may be advantageous in ensuring hemostatic sealing during changes in the tissue inflammatory response and throughout the healing process.

[0065] Figures 11A and 11B show a top and side view of the auxiliary material 604 after the staples 300 have been fired and the tissue T has been cut. As shown, the auxiliary material 604 may be split into two after firing. Where the auxiliary material 604 comes into contact with the tissue T, ridges 604e, 604f may be formed, corresponding to variations in the texture and thickness of the tissue. This means that the auxiliary material 604 can adapt to different heights and compressions depending on the application.

[0066] Figure 12 is a flowchart of a method 1200 for forming a surgical adjuvant 604 comprising a bioabsorbable material that itself contains a porous body. The techniques for spatial control of mechanical properties described herein may provide additional benefits, such as increasing the strength and durability of the adjuvant when the adjuvant is delivered to a tissue site, in combination with positive bio-interactions (e.g., biocompatibility, wound healing, tissue integration, chemotherapy, anti-inflammatory, bone growth and integration, ligament and tendon repair, etc.). Thus, the techniques described herein may enable the bioabsorbable material itself to assist in the healing process of surrounding tissues. Furthermore, the implantation techniques described herein may provide additional benefits, such as preventing fibrous encapsulation of foam cushions and / or providing an adjustable release profile of various medical additives delivered to the tissue site.

[0067] Specifically, with respect to Figure 12, Method 1200, used for spatial control of the mechanical properties of a bioabsorbable material (e.g., foam), may include chemically reacting a polyol with an isocyanate to form a porous body (Step 1202). In some examples, the bioabsorbable material may include polyurethane. Method 1200 also includes adding a polymerizable compound to at least a portion of the porous body (Step 1204). The polymerizable compound is at least one of a chain extender and a photoinitiator. After the introduction of the polymerizable compound, Method 1200 includes exposing the porous body and the polymerizable compound to at least one of heat, light, ultrasound, and pH (Step 1206). Method 1200 may end after Step 1206, or optionally include adding a medical additive to the porous body (Optional Step 1208). In such examples, the medical additive may include an agent for treating pain and / or for promoting wound healing, tissue growth, infection reduction, etc. In a similar manner, the crosslink density can be varied by other process parameters in addition to the addition of polymerizable compounds. For example, the chemical framework of a bioabsorbable material may vary from zone to zone, or its density may vary from zone to zone due to manipulated mechanical or other chemical properties when producing the bioabsorbable material.

[0068] As those skilled in the art will understand, the embodiments described above are by illustrative reference only, and the present invention is not limited to those specifically illustrated and described herein. Rather, the scope of the present invention includes both combinations and partial combinations thereof of the various features described herein, as well as variations and modifications thereof not disclosed in the prior art, which will be conceivable to those skilled in the art by reading the above description.

[0069] In some cases, the disclosed devices (e.g., end effectors, surgical aids, and / or staple cartridges), and methods involving one or more of the disclosed devices, may be subject to one or more of the following provisions.

[0070] Clause 1: A bioabsorbable material configured to be delivered to tissue, comprising a porous body containing at least one polymer including a first zone having a first crosslink density and a second zone having a second crosslink density different from that of the first zone, wherein at least the first and second zones form a gradient of compressive strength along a portion of the porous body.

[0071] Clause 2: The material according to Clause 1, wherein the porous body comprises polyurethane, and at least one of the first zone and the second zone comprises a polymerizable compound comprising crosslinkable units, wherein the polymerizable compound is configured to react with the polyurethane upon exposure to a stimulus and undergo crosslinking between the crosslinkable units.

[0072] Clause 3: The material described in Clause 2, wherein the stimulus includes at least one of heat, light, ultrasound, and pH.

[0073] Clause 4: The material according to Clause 2, wherein the polymerizable compound comprises at least one of a chain extender, a reactive monomer, a photoinitiator, and a stimulus-responsive functional group, and at least one of the chain extender, reactive monomer, photoinitiator, and stimulus-responsive functional group is configured to regulate the amount of crosslinking between crosslinking units.

[0074] Clause 5: The material described in Clause 4, wherein the chain extender comprises fumaric acid, succinic acid, maleic acid, or a combination thereof.

[0075] Clause 6: The material described in Clause 2, wherein the polymerizable compound includes acrylates, methacrylates, arylboronic acids, styrylpyrene, styrene, vinyl acetate, acrylonitrile, vinylidene dichloride, isoprene, butadiene, chloroprene, or a combination thereof.

[0076] Section 7: The material according to Section 2, wherein the polymerizable compound is further configured to decompose to form degradation products, the degradation products, when released in or near tissue, function as a drug.

[0077] Clause 8: The material according to Clause 1, wherein the second zone is located approximately in the center along the longitudinal axis of the porous body (LP).

[0078] Clause 9: The material according to Clause 1, wherein the second zone is located at both nearly opposite ends of the porous body.

[0079] Clause 10: The material according to Clause 1, wherein the second zone is coated on at least one side of the first zone.

[0080] Clause 11: The material described in Clause 10, the coating having a thickness of approximately 20 μm to approximately 100 μm.

[0081] Clause 12: The material according to Clause 1, wherein the foam has a compressive strength of approximately 30 to approximately 70 kPa in the first zone and a compressive strength of approximately 15 to approximately 50 kPa in the second zone.

[0082] Clause 13: The material described in Clause 1, wherein the second zone contains a lower crosslink density than the first zone.

[0083] Clause 14: A method for forming a bioabsorbable material, comprising the steps of: chemically reacting a polyol with an isocyanate to form a porous body; and adding a polymerizable compound to at least a portion of the porous body, wherein the polymerizable compound comprises crosslinkable units, and the polymerizable compound is configured to undergo crosslinking between the crosslinkable units upon exposure to a stimulus, thereby adjusting the crosslinking density of the porous body.

[0084] Clause 15: The method according to Clause 14, wherein the porous body contains polyurethane.

[0085] Clause 16: The method according to Clause 14, wherein the polymerizable compound comprises at least one of a chain extender, a reactive monomer, a photoinitiator, and a stimulus-responsive functional group, and at least one of the chain extender, reactive monomer, photoinitiator, and stimulus-responsive functional group is configured to regulate the amount of crosslinking between crosslinking units when exposed to a stimulus.

[0086] Clause 17: The method according to Clause 14, further comprising the step of applying a polymerizable compound to the vicinity center along the longitudinal axis of a porous body.

[0087] Clause 18: The method according to Clause 14, further comprising the step of applying a polymerizable compound to substantially opposite ends of a porous body.

[0088] Clause 19: The method according to Clause 14, further comprising the step of exposing the porous material and the polymerizable compound to at least one of heat, light, ultrasound, and pH.

[0089] Clause 20: The method according to Clause 14, further comprising the step of adding a medical additive to a porous body, wherein one or more medical additives are further configured to chemically bond with a polymerizable compound and be released in or near the tissue over a predetermined period of time.

[0090] Clause 21: A bioabsorbable material configured to be delivered to tissue, comprising a porous body containing at least one polymer including a first zone having a first crosslink density and a second zone having a second crosslink density different from that of the first zone, wherein the first and second zones form a gradient of compressive strength along a portion of the porous body.

[0091] Clause 22: The material according to Clause 21, wherein the porous body comprises polyurethane, and at least one of the first zone and the second zone comprises a polymerizable compound comprising crosslinkable units, wherein the polymerizable compound is configured to react with the polyurethane upon exposure to a stimulus and undergo crosslinking between the crosslinkable units.

[0092] Clause 23: The materials described in Clauses 21-22, wherein the irritant includes at least one of heat, light, ultrasound, and pH.

[0093] Clause 24: The material according to any one of Clauses 22 to 23, wherein the polymerizable compound comprises at least one of a chain extender, a reactive monomer, a photoinitiator, and a stimulus-responsive functional group, and at least one of the chain extender, reactive monomer, photoinitiator, and stimulus-responsive functional group is configured to regulate the amount of crosslinking between crosslinking units.

[0094] Clause 25: The material described in Clause 24, wherein the chain extender comprises fumaric acid, succinic acid, maleic acid, or a combination thereof.

[0095] Clause 26: The material according to any of Clauses 22 to 25, wherein the polymerizable compound includes acrylates, methacrylates, arylboronic acids, styrylpyrene, styrene, vinyl acetate, acrylonitrile, vinylidene dichloride, isoprene, butadiene, chloroprene, or a combination thereof.

[0096] Clause 27: A material according to any of Clauses 22-26, wherein the polymerizable compound is further configured to decompose to form degradation products, the degradation products, when released in or near tissue, function as a pharmacokinetic agent.

[0097] Clause 28: The material according to any of Clauses 21 to 27, wherein the second zone is located approximately in the center along the longitudinal axis of the porous body.

[0098] Clause 29: The material according to any of Clauses 21-27, wherein the second zone is located at both substantially opposite ends of the porous body.

[0099] Clause 30: The material according to any one of Clauses 21 to 27, wherein the second zone is coated on at least a portion of one side of the first zone.

[0100] Clause 31: The material described in any of Clauses 28 to 30, wherein the second zone includes a thickness of approximately 20 μm to approximately 100 μm.

[0101] Clause 32: A material according to any one of Clauses 21 to 31, wherein the material has a compressive strength of approximately 30 to approximately 70 kPa in the first zone and a compressive strength of approximately 15 to approximately 50 kPa in the second zone.

[0102] Clause 33: The material according to any of Clauses 21 to 32, wherein the second zone contains a lower crosslink density than the first zone.

[0103] Clause 34: The material according to any one of Clauses 21 to 33, further comprising one or more medical additives configured to remain chemically bonded with a polymerizable compound in at least one of the first or second zones.

[0104] Clause 35: The material described in Clause 34, further configured to release one or more medical additives in or near tissue over a specified period of time.

[0105] [Implementation Method] (1) A bioabsorbable material configured to be delivered to tissue, A first zone including the first crosslinking density, A porous body comprising at least one polymer, including a second zone having a second crosslink density different from that of the first zone, A bioabsorbable material wherein at least the first zone and the second zone form a compressive strength gradient along a portion of the porous body. (2) The material according to Embodiment 1, wherein the porous body comprises polyurethane, and at least one of the first zone and the second zone comprises a polymerizable compound comprising crosslinkable units, wherein the polymerizable compound is configured to react with the polyurethane and undergo crosslinking between crosslinkable units when exposed to a stimulus. (3) The material according to Embodiment 1 or 2, wherein the stimulus includes at least one of heat, light, ultrasound, and pH. (4) The polymerizable compound comprises at least one of a chain extender, a reactive monomer, a photoinitiator, and a stimulus-responsive functional group, The material according to any one of embodiments 2 to 3, wherein at least one of the chain extender, the reactive monomer, the photoinitiator, and the stimulus-responsive functional group is configured to adjust the amount of crosslinking between crosslinking units. (5) The material according to Embodiment 4, wherein the chain extender comprises fumaric acid, succinic acid, maleic acid, or a combination thereof.

[0106] (6) The material according to any one of Embodiments 2 to 5, wherein the polymerizable compound comprises acrylate, methacrylate, arylboronic acid, styrylpyrene, styrene, vinyl acetate, acrylonitrile, vinylidene dichloride, isoprene, butadiene, chloroprene, or a combination thereof. (7) The material according to any one of embodiments 2 to 6, wherein the polymerizable compound is further configured to decompose to form degradation products, the degradation products, when released in or near the tissue, function as a drug. (8) The material according to any one of embodiments 1 to 7, wherein the second zone is located substantially in the center along the longitudinal axis of the porous body or along the vertical plane. (9) The material according to any one of embodiments 1 to 7, wherein the second zone is located at substantially opposite ends of the porous body. (10) The material according to any one of embodiments 1 to 7, wherein the second zone is coated on at least a portion of one side of the first zone.

[0107] (11) The material according to any one of embodiments 8 to 10, wherein the coating has a thickness of about 20 μm to about 100 μm. (12) The material according to any one of embodiments 1 to 11, wherein the material has a compressive strength of about 30 to about 70 kPa in the first zone and a compressive strength of about 15 to about 50 kPa in the second zone. (13) The material according to any one of embodiments 1 to 32, wherein the second zone has a lower crosslinking density than the first zone. (14) The material according to any one of embodiments 1 to 13, further comprising one or more medical additives configured to remain chemically bonded with the polymerizable compound in at least one of the first zone or the second zone. (15) The material according to Embodiment 14, wherein one or more medical additives are further configured to be released in or near the tissue over a predetermined period of time.

Claims

1. A bioabsorbable material configured to be delivered to tissue, A first zone including a first crosslinking density, A porous body comprising at least one polymer, including a second zone having a second crosslinking density different from that of the first zone, A bioabsorbable material wherein at least the first zone and the second zone form a compressive strength gradient along a portion of the porous body.

2. The material according to claim 1, wherein the porous body comprises polyurethane, and at least one of the first zone and the second zone comprises a polymerizable compound comprising crosslinkable units, wherein the polymerizable compound is configured to react with the polyurethane and undergo crosslinking between crosslinkable units when exposed to a stimulus.

3. The material according to claim 1 or 2, wherein the stimulus includes at least one of heat, light, ultrasound, and pH.

4. The polymerizable compound comprises at least one of a chain extender, a reactive monomer, a photoinitiator, and a stimulus-responsive functional group. The material according to claim 2, wherein at least one of the chain extender, the reactive monomer, the photoinitiator, and the stimulus-responsive functional group is configured to adjust the amount of crosslinking between crosslinking units.

5. The material according to claim 4, wherein the chain extender comprises fumaric acid, succinic acid, maleic acid, or a combination thereof.

6. The material according to claim 2, wherein the polymerizable compound comprises acrylate, methacrylate, arylboronic acid, styrylpyrene, styrene, vinyl acetate, acrylonitrile, vinylidene dichloride, isoprene, butadiene, chloroprene, or a combination thereof.

7. The material according to claim 2, wherein the polymerizable compound is further configured to decompose to form degradation products, the degradation products, when released in or near the tissue, function as a drug.

8. The material according to claim 1, wherein the second zone is located substantially in the center along the longitudinal axis of the porous body or along a vertical plane.

9. The material according to claim 1, wherein the second zone is located at substantially opposite ends of the porous body.

10. The material according to claim 1, wherein the second zone is coated on at least a portion of one side of the first zone.

11. The material according to claim 8, wherein the coating has a thickness of about 20 μm to about 100 μm.

12. The material according to claim 1, wherein the material has a compressive strength of about 30 to about 70 kPa in the first zone and a compressive strength of about 15 to about 50 kPa in the second zone.

13. The material according to claim 1, wherein the second zone includes a lower crosslinking density than the first zone.

14. The material according to claim 1, further comprising one or more medical additives configured to remain chemically bonded with the polymerizable compound in at least one of the first zone or the second zone.

15. The material according to claim 14, wherein one or more medical additives are further configured to be released in or near the tissue over a predetermined period of time.

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