NONUNIFORM EMBROIDERED SOFT TISSUE IMPLANT STRUCTURE

Described herein are implants (e.g., medical textiles/biotextiles) that include nonuniform stitching patterns to reinforce and bolster the tensile strength of a substrate base and provide customized compliance characteristic to the implant. In some examples, the nonuniform stitching pattern does not substantially change the compliance of the implant relative to the substrate in directions along a plane of the substrate. In some examples, the nonuniform stitching pattern creates a nonuniform directional compliance characteristic to the implant. The implants may be configured as surgical grafts that may be used for soft tissue reconstruction, regeneration, or repair.

INCORPORATION BY REFERENCE

FIELD

The apparatuses and methods described herein relate generally to surgical grafts and medical textiles useful for soft tissue reconstruction, regeneration, or repair. More particularly, described herein are surgical implants for soft tissue repair that include nonuniform stitching pattern that imparts tensile strength and a customized compliance to the implant.

BACKGROUND

Soft tissues within a body may benefit from repair or reinforcement due to a variety of reasons such as disease, enhancement, or trauma.

An implant or medical textile may be used to repair or reinforce a soft tissue, such as an unhealthy or modified tissue in the body. The tissue may, for example, be tissue that is no longer able to maintain its shape or physiological function such as a hernia or a tissue for which a shape or size change is desired such as breast size or shape change due to breast enhancement or breast reconstruction. A hernia is a condition in which part of an organ or fatty tissue protrudes through the wall of a surrounding tissue. Abdominal wall hernia surgery is one of the most common surgical procedures, and according to the U.S. Food and Drug Administration, more than 1 million hernia repairs are performed in the United States alone. Common adverse events associated with hernia repair surgery include pain, infection, hernia recurrence, adhesion formation, obstruction, bleeding, and fluid build-up. Breast reconstruction may be performed to reconstruct a breast after a mastectomy has been performed to remove a diseased tissue due to cancer or as a prophylactic measure to prevent cancer. Common adverse events associated with breast reconstruction include infection, pain, delayed healing, and swelling.

There is a need for improved surgical repair materials and medical textiles.

SUMMARY OF THE DISCLOSURE

Described herein are surgical implants including grafts and medical textiles that include a nonuniform stitching pattern embroidered into a substrate. The substrate may include one or more layers of a biotextile (biologic) or medical textile (polymer based). The nonuniform stitching pattern may provide localized tensile strength to the implant yet allow the implant to deform in multiple directions with respect to a plane of the substrate, or provide the implant with unequal extents of compliance in different directions along the plane of the implant.

The implants may be used in the repair and/or plastic reconstruction of soft tissue. For example, the implants may be implemented as a surgical repair material, surgical repair mesh (or scaffold or patch), a hernia mesh (or scaffold or patch), etc. The surgical repair implant may be useful for supporting or repairing a body tissue such as for breast reconstruction, hernia repair, pelvic organ prolapse treatment, among other soft tissue repair and reconstruction uses.

According to one example, an implant for repairing or reconstructing soft tissue includes: a substrate comprising a biotextile or a medical textile having an upper surface and a lower surface; and a nonuniform stitching pattern embroidered into the substrate that increases a strength of the implant relative to the substrate without changing a compliance of implant relative to the substrate, wherein the nonuniform stitching pattern includes one or more filaments stitched into curved lines forming a plurality of adjacent cells having non-parallel sides across the upper surface of the substrate.

The one or more filaments stitched into curved lines may have a radius of curvature that varies along the curved lines. The absolute value of the radius of curvature may be greater than 3 millimeters.

The nonuniform stitching pattern may be configured so that the one or more filaments intersect at corners of the plurality of adjacent cells at a shared intersection stitching point. The plurality of adjacent cells may have a plurality of different shapes comprising two-sided, three-sided, four-sided, five-sided, and six-sided shapes. The plurality of adjacent cells may form an irregular pattern across the upper surface of the substrate.

The substrate may include a plurality of layers of material. The nonuniform stitching pattern may be stitched into two or more of the plurality of layers of materials. The substrate may include a sheet of extracellular matrix material (ECM). The implant may be configured as a graft for one or more of hernia repair and tissue reconstruction.

The plurality of adjacent cells may have a distribution of surface areas greater than 1 mm2. The plurality of adjacent cells may have a distribution of areas between about 1 mm2and 100 mm2. The plurality of adjacent cells may have approximately the same area.

The implant may further include a border stitch around a perimeter of the implant.

The one or more filaments may include a biocompatible material. The biocompatible material may be resorbable.

According to another example, an implant for repairing or reconstructing soft tissue includes: a substrate comprising a biotextile or a medical textile having an upper surface and a lower surface; and a nonuniform stitching pattern embroidered into the substrate, wherein the nonuniform stitching pattern includes one or more filaments stitched into curved lines forming a plurality of adjacent cells having non-parallel sides across the upper surface of the substrate, wherein the one or more filaments stitched into curved lines has a radius of curvature that varies along the curved lines, so that the implant has the same compliance in any direction in the plane of the substrate.

According to further example, a method for forming an implant for repairing or reconstructing soft tissue includes: stitching one or more filaments into a substrate to form a nonuniform stitching pattern in the substrate, the substrate comprising a biotextile or a medical textile, where the nonuniform stitching pattern increases a strength of the implant relative to the substrate without changing a compliance of implant relative to the substrate, wherein the nonuniform stitching pattern includes the one or more filaments stitched into curved lines forming a plurality of adjacent cells having non-parallel sides across an upper surface of the substrate, so that the implant has the same compliance in any direction in the plane of the substrate.

The method may further include testing the compliance in one or more directions along the plane of the substrate to confirm that the implant has the same compliance in any direction in the plane of the substrate. The method may further include determining the nonuniform stitching pattern. The substrate may include one or more layers of the biotextile or the medical textile, wherein stitching the one or more filaments into the substrate includes stitching the one or more filaments into the one or more layers of the biotextile or the medical textile. Stitching the one or more filaments into the substrate may include stitching the one or more filaments so that the curved lines have radius of curvature that varies along the curved lines. Stitching the one or more filaments into the substrate may include stitching the one or more filaments in a lock-stitch configuration. Stitching the one or more filaments into the substrate may include stitching one or more non-parallel lines, curved shapes, circles, ovals, irregular shapes, loops, dots, or any combination thereof into the substrate.

According to another example, a method of using an implant for repairing or reconstructing soft tissue includes: surgically implanting the implant with a patient's body, wherein the implant includes a nonuniform stitching pattern embroidered into a substrate that increases a strength of the implant relative to the substrate without changing a compliance of implant relative to the substrate, wherein the nonuniform stitching pattern includes one or more filaments stitched into curved lines forming a plurality of adjacent cells having non-parallel sides across an upper surface of the substrate.

Surgically implanting the implant may include orienting the upper surface of the substrate nearer to a particular tissue type of the patient's body relative to a lower surface of the substrate that is opposite the upper surface.

These and other examples are described further herein.

All of the methods and apparatuses described herein, in any combination, are herein contemplated and can be used to achieve the benefits as described herein.

DETAILED DESCRIPTION

Described herein are soft tissue implants including textiles (e.g., biotextiles and/or medical textiles) that include a substrate into which a filament (which may also be referred to as a thread, yarn, fiber, suture, or strand) is sewn and formed into a nonuniform stitch pattern. The nonuniform stitching pattern may be used to locally increase the strength of the substrate while controlling a degree of compliance of the substrate. In some variations, the nonuniform stitching pattern does not substantially decrease the overall compliance of the implant relative to the substrate, thus allowing the implant to deform and stretch in multiple directions. In other variations, the nonuniform stitching pattern nonuniformly increases the compliance of the implant such that the implant is more compliant in certain directions than others.

Biotextile or medical textile material are typically used for soft tissue repair or reconstruction and may be surgically implanted within the body. Such soft tissue implants may serve, for example, to replace or reinforce diseased or damaged soft tissue, or to hold internal organs in place in the case of a hernia repair. In some cases, these soft tissue implants are intended to be a permanent fixture within the body, for example, medical textile implants comprising permanent polymeric threads. In other cases, the soft tissue implants are intended to be a temporary fixture within the body such that they are made of a material that is gradually resorbed by the body as it is replaced by the body's own tissue, for example, biotextile implants comprising an extracellular matrix. Regardless, patients do not all heal at the same rate, owing to the particular condition in need of repair, and the physical characteristics and conditions of the patient. Accordingly, it is desirable to control the inherent base properties of such implants to accommodate the conditions of individual patients. In addition, it is desirable to compensate for premature breakdown or resorption of the implant.

The nonuniform stitching pattern may be used to locally increase the strength of a substrate while controlling the degree of compliance of the resulting implant. As used herein, a nonuniform stitching pattern refers to a stitching pattern that has a varied geometric characteristic. For example, a nonuniform stitching pattern may include stitches that form nonuniform shapes, such as curved lines (e.g., wavy lines, looped lines), geometric shapes with curved sides, irregular geometric shapes or lines, complex geometric shapes, or other nonuniform shapes. Alternatively or additionally, a nonuniform stitching pattern may include shapes (uniformly shaped or nonuniformly shaped) that are distributed in a nonuniformly arrangement on the substrate. For example, a nonuniform stitching pattern may include a nonuniform arrangement of lines (e.g., non-parallel lines or irregularly arranged lines) and/or a nonuniform arrangement of geometric shapes (e.g., circles, ovals, dots). A nonuniform stitching pattern may include nonuniform shapes that are nonuniformly arranged on the substrate. In some variations the shapes intersect with each other on the substrate. In other variations the shapes do not intersect with each other on the substrate. In some variations, the nonuniform stitching pattern includes a pattern of smooth lines that do not meet at sharp angles so as to avoid stress concentrators.

In some variations, the nonuniform stitch pattern does not change (or does not substantially change) the overall compliance of the implant relative to the substrate. Compliance refers to the ability of an implant or substrate to or deform or stretch in response to certain load forces and is a function of, among other things, strength, stress, elongation, rebound, deformability, and elasticity properties of the particular materials or combination of materials. Compliance and tensile strength may be measured along a plane of the implant or substrate in one or more directions. In some examples, not substantially changing the compliance means changing the compliance of the substrate by no more than 10% (e.g., by no more than 10%, 8%, 7%, 6%, 5%, 4%, 3%, 2% or 1%). In some variations, the nonuniform stitch pattern may be configured not to substantially change the overall compliance of the implant in multiple directions (e.g., all directions) compared to the substrate without the nonuniform stitch pattern. In other variations, the nonuniform stitch pattern may be configured to change the compliance of the substrate such that the implant is more compliant in one or more predetermined directions along the plane of the substrate compared to the substrate without the nonuniform stitch pattern.

FIG.1shows an example implant100having a uniform stitching pattern. The implant100includes a substrate102that includes a filament104that is stitched into the substrate in a pattern of parallel lines (crosshatched pattern). The crosshatched pattern includes a first series of parallel stitch lines108that intersects with a second series of parallel stitch lines110. In this example, the crosshatched pattern forms squares having sides of length D1and diagonal distances D2. Also in this example, the implant100includes a border stitch106, which includes a line stitch112that follows the perimeter edge of the substrate102, and a zig-zag stitch114that is stitched over the line stitch112in a zig-zag pattern. In addition to strengthening the substrate102, the uniform stitching pattern may increase the compliance of the implant100relative to the substrate102.

FIG.2shows an example soft tissue implant200having a nonuniform stitching pattern203, according to some embodiments. A filament204is stitched in a substrate202along one or more embroidery paths220that form the nonuniform stitching pattern203and a border stitch212. The embroidery path(s)220may include curved sections, straight sections, and angled direction changes. In this example, the nonuniform stitching pattern203includes a pattern of curved lines that intersect at intersections216. The curved lines may create a smooth path to avoid stress concentrators. As shown, none of the lines in the nonuniform stitching pattern203are parallel to each other. The border stitch212follows the perimeter edge of the substrate202and surrounds the area of the substrate202with the nonuniform stitching pattern203. In this example, the border stitch212includes a single line stitch. In other examples, the border stitch may alternatively or additionally include a different type of stitch, such as a zig-zag stitch similar to the zig-zag stitch114in the example ofFIG.1.

The nonuniform stitch pattern203can provide localized tensile strength to the implant200. In this way, the implant200can withstand localized tensile forces applied to when implanted within a patient's body. In the aggregate, the nonuniform stitch pattern203may not provide a particular directional compliance contribution. For example, the nonuniform stitch pattern203may cause the implant200not to deform more in any one direction along the plane of the substrate202. That is, the implant200can deform and stretch in multiple directions, and may not be biased to deform/stretch in any one particular direction. In this way, the nonuniform stitch pattern203may provide the implant200with more overall in-plane compliance (along the plane of the substrate202) compared to the uniform crosshatched stitch pattern of implant100.

The nonuniform stitch pattern203forms smooth lines that do not meet at sharp angles so as to avoid stress concentrators. In the example shown, the curved lines of the nonuniform stitch pattern203have a radius of curvature that varies along the curved lines. In some cases, the absolute value of the radius of curvature of the curved lines is greater than three (3) millimeters (mm). In some variations, the overall radius of curvature of the curved lines may be between one tenth ( 1/10th) and one one-hundredth ( 1/100th) of the overall area of the substrate202. In some variations, the radius of curvature of the curved lines ranges between one eighth (⅛th) of an inch to one tenth 1/10th) of an inch.

As shown in the close-up view201of a portion of the implant200, the filament204penetrates the substrate202multiple times to form multiple stitches222where the filament204is exposed on one side of the implant200(side shown inFIG.2). The nonuniform stitch pattern203may be chosen so as to reduce or minimize the exposure of the filament204on one side of the implant200(e.g., side shown inFIG.2). This may be advantageous in cases where it is preferable to limit or minimize contact of the material of the filament204to certain body tissues (e.g., bowels). For example, some polymer materials in which the filament204may be made from a polymer material that may tend to adhere to certain body tissues (e.g., as compared to the material of the substrate202). However, if the amount of filament204is reduced too much, the substrate202will not have sufficient tensile strength. Thus, the nonuniform stitch pattern203may be chosen based on a balance between providing sufficient tensile strength/compliance as and reducing exposure of the filament204to certain tissues (to at least an exposed side of the implant200). In this particular case, the nonuniform stitch pattern203may reduce exposure of the filament204on the front side of the implant200shown inFIG.2by 33.6% compared to exposure of the filament104in the crosshatched stitch pattern on the front side of implant100shown inFIG.1.

Also as shown in the close-up view201, the filament204passes through holes224in the substrate202created during the stitching process. At the intersections216of the curved lines, the filament204passes through shared holes226in the substrate202. This configuration may help to maintain the integrity (reduce weakening) of the substrate202compared to stitching arrangements where the substrate202has multiple holes for accommodating the filament204at each intersection216. In some variations, the hole226at each of the intersections216is the same size (e.g., diameter) as non-shared holes224, which may also help to maintain the integrity (reduce weakening) of the substrate202compared to larger holes to accommodate multiple passes of the filament204.

The nonuniform stitch pattern203can form cells218, which correspond to areas of the substrate202having boundaries defined by the nonuniform stitch pattern203of the filament204. The cells218have non-parallel sides in accordance with the non-parallel curved lines of the nonuniform stitch pattern203. The filament204intersects at shared intersection stitching points216at corners of the cells218. As shown, the cells218may have different shapes and have a different number of sides (e.g., two-sided, three-sided, four-sided, five-sided, and six-sided shapes). The cells218themselves may form a nonuniform pattern across the surface of the substrate402.

The nonuniform stitch patterns described herein (including the nonuniform stitch pattern203) may be designed such the size (area) of each of the cells is the same or similar (e.g., differ in area by no more than 1% to 10% (e.g., 1%, 3%, 5%, 8%, or 10%). In some variations, the nonuniform stitch pattern203is designed such that the area of the cells varies (e.g., vary in area by more than 10% to 99% (e.g., 10%, 12%, 15%, 20%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 99%). In some variations, whether the area cells are the same or vary, the cells may have a consistent average cell area across the substrate. In some cases, the cells may have a distribution of surface areas greater than 1 mm2. In some cases, the cells have a distribution of surface areas between about 1 mm2and 100 mm2.

In some variations, the cells of any of the nonuniform stitch patterned implants described herein (such as cells218of implant200) may be configured to absorb fluid to form pockets of fluid within the implant. For example, if the substrate includes multiple layers of material, the fluid may enter the cells between adjacent layers. In some cases, this may advantageously increase the local strength of the implant without impacting the overall compliance of the implant. In some examples, the swelling of cells with fluid may the change the surface contour of the substrate. For example, such swelling of the cells may at least partially eclipse the filament such that less of the filament is exposed on the outer surface implant, which may be desirable in some cases.

Any of a number of suitable materials may be used for the filaments described herein, including polymeric materials and non-polymeric materials. For example, the filament may be a monofilament or include multiple sub-filaments. Examples of filaments polymer materials may include one or more permanent polymers (e.g., polyethylene terephthalate (PET), polypropylene, nylon, polytetrafluoroethylene (PTFE)). Other permanent materials (metals, organic materials, etc.) may additionally or alternatively be used. In some examples, the filament is made of a biodegradable (e.g., resorbable) polymer. In some variations the stitching is made from one or more filaments that include a mixture of permanent and biodegradable (e.g., resorbable) polymers.

The substrate in any of the examples described herein may be made of any of a number of materials. Non-limiting examples of substrate materials may include cloth or fabric, lace, leather, silk, linen, nylon, polyester, polypropylene, polyethylene, cotton, satin, wool, bamboo, cashmere, jute, burlap, fleece, felt, spandex, rayon, denim, and other suitable materials, or any combination thereof. In some cases, the substrate is made of a textile material, which may be obtained or derived from living tissue and/or be a synthetic material. Living tissue may include, for example, dermis/skin tissue, sub-tissue, extracellular matrices (ECMs), pericardium, peritoneum, intestine, stomach, forestomach, and other suitable tissues. The animal source may be any suitable animal, including a human, pig, cow, or sheep, or may be synthesized, for example, by recombinant expression. In some cases, the substrate material may be biodegradable or resorbable. Some non-limiting examples of biotextiles include extracellular matrix-derived tissue scaffolds, autograft tissue, allograft tissue, and xenograft tissue, as well as artificial skin, artificial heart valves, and other implantable prosthetics. Some non-limiting examples of synthetic materials include polypropylene, polyethylene, and/or other implantable polymer materials. The substrate may be woven or non-woven. In some cases, the substrate may be or include a mesh obtained or derived from living tissue and/or made of a synthetic material. Any of the substrates described herein may have a smooth surface, a textured surface, or a combination of smooth and textured surfaces.

Any of the substrates and/or filaments described herein may be coated and/or impregnated with one or more agents (e.g., antibiotics and/or anti-inflammatory agents). Any of the sewn textures may include (including as a filament or part of a filament) a radiopaque material such as, but not limited to, barium doped or metallic (gold, Pt, Pt Iridium, etc.).

Any of the substrates described herein may include any number of layers (also referred to as sheets) of material. For example, a substrate may include one, two, three, four, five, six, seven or more layers of material. If the substrate includes two or more layers of material, the nonuniform stitching pattern may secure two or more of the layers together.

FIG.3shows an example substrate302that includes four layers302a,302b,302cand302dof material. The nonuniform stitching pattern may be stitched through one, two, three or all four of the layers302a,302b,302cand302d. In some variations all layers of a substrate are made of the same material, while in other variations the layers are made of one or more different materials.

The nonuniform stitch patterns described herein may be stitched in a substrate in a lock-stitch configuration/pattern where one side of the implant has a different stitch configuration than the opposite side of the implant.FIG.4shows a side view and a close-up view of an example implant400illustrating one example of a lock-stitch configuration. In this example, the substrate402includes multiple (i.e., four) layers of material. A first (e.g., upper) filament404is sewn through the substrate402such that a nonuniform stitching pattern403is formed on a first (e.g., upper) side420of the implant400(and substrate402). As shown, the first filament404forms a loop407and captures a second (e.g., lower) filament405on a second (e.g., lower) side422of the implant400(and substrate402), thereby forming the lock-stitch configuration. The loop407of the first filament404and the second filament405form a reverse stitch pattern409on the second side422of the substrate402.

In some examples, the first filament404and the second filament405are separate filaments. The first filament404may be made of the same material as the second filament405, or may be made of a different material than the second filament405. In other examples, the first filament404and the second filament405are continuous with each other and part of the same filament.

The lock-stitch configuration results in the first side420of the implant400generally having a smoother surface contour than the second side422of the implant400. In addition, the first side420of the implant400generally has less surface area taken by a filament (i.e., filament404) than the second side422of the implant400. Thus, the first side420and second side422of the implant400may have different surface properties that may dictate which side is preferentially placed next to certain tissues when implanted within a patient's body. For example, it may be preferable to place the smoother first side420, which includes the nonuniform stitching pattern403, against tissue areas closer to certain body organs relative to the rougher second side422. In some variations, the material (e.g., type of polymer) of the first filament404may be chosen to minimize biological response with body tissue, which may or may not be different than the material of the second filament405that may not be expected to interact with tissue to the same extent as the first filament404when implanted in the body.

As discussed previously, the first filament404passes through holes424of the substrate402to create the lock-stitch configuration. As illustrated in the close-up view401, the holes424may provide pathways (channels) for bodily fluid (e.g., blood) to transfer through the substrate402, which may promote absorption of bodily fluid during implantation of the implant400and enable cellular migration during healing.

The nonuniform stitching patterns described herein may form any of a number of various shapes and patterns on the surface of the implant. In some variations, the nonuniform stitching patterns form irregular shapes. In other variations, the nonuniform stitching patterns form uniform or nonuniform shapes that are nonuniformly distributed on the substrate.

FIGS.5A-5Hshow examples of different nonuniform stitching patterns.FIG.5Ashows an example nonuniform stitching pattern503in which a filament504forms a curved line that crosses itself. The nonuniform stitching pattern503is similar to the nonuniform stitching pattern203inFIG.2but with a different size distribution of cells518. In some variations, the filament504may enter the substrate shared holes at intersection points516, similar to the hole226of the substrate202discussed above with reference toFIG.2.

FIG.5Bshows an example nonuniform stitching pattern533in which a filament534forms a curved line that does not cross itself.

FIG.5Cshows an example nonuniform stitching pattern543in which a filament544forms a tightly curved (curly) line that crosses itself. In some variations, the filament544may enter the substrate shared holes at intersection points546, similar to the hole226of the substrate202discussed above with reference toFIG.2.

FIG.5Dshows an example nonuniform stitching pattern553in which a filament554forms a series of circles (also referred to as bubbles) that cross each other. In the example shown, the circles are the same size (diameter). In other examples, the circles may be different sizes (diameters). In some examples, the stitching pattern includes closed curved shapes other than circles, such as ovals, irregularly shaped closed shapes, or a combination thereof. In some variations, the filament554may enter the substrate shared holes at intersection points556, similar to the hole226of the substrate202discussed above with reference toFIG.2.

FIG.5Eshows an example nonuniform stitching pattern563in which a filament564forms a series of circles that do not cross each other, thereby forming a series of islands. The circles may be equidistantly distributed or non-equidistantly distributed on the substrate surface. The circles may be randomly (or pseudo-randomly) distributed on the substrate surface, or distributed in a predetermined pattern on the substrate surface. In the example shown, the circles are the same size (diameter). In other examples, the circles may be different sizes (diameters).

FIG.5Fshows an example nonuniform stitching pattern573in which a filament574forms a series of circles577that are connected to each other by lines579, thereby forming a series of connected islands. In the example shown, the circles are the same size (diameter). In other examples, the circles may be different sizes (diameters). In some cases, each circle577is formed by forming a loop such that the filament574overlaps with itself as indicated by arrow571.

FIG.5Gshows an example nonuniform stitching pattern583in which a filament584forms a series of dots within the substrate, thereby forming a mattress-like surface to the implant. This stitching pattern may be useful in situations where it is desirable to minimize the amount of surface area of the implant that the filament584takes. The dots may be equidistantly distributed or non-equidistantly distributed on the substrate surface. The dots may be randomly (or pseudo-randomly) distributed on the substrate surface, or distributed in a predetermined pattern on the substrate surface. The dots may be the same size or be different sizes.

FIG.5Hshows an example nonuniform stitching pattern593in which a filament594forms a series of disconnected curved lines within the substrate. The disconnected curved lines may be equidistantly distributed or non-equidistantly distributed on the substrate surface. The disconnected curved lines may be randomly (or pseudo-randomly) distributed on the substrate surface, or distributed in a predetermined pattern on the substrate surface. The disconnected curved lines may be the same size (e.g., length) or be different sizes (e.g., lengths).

FIG.6is a flowchart indicating an example method of forming an implant having a nonuniform stitching pattern. At601, a nonuniform stitching pattern is determined for stitching into a substrate to form an implant with a greater local tensile strength than the substrate. As discussed, the nonuniform stitching pattern may not change (or not substantially change) an overall compliance of the implant relative to the substrate, or makes the implant more compliant in a particular direction in the plane of the substrate. The nonuniform stitching pattern may be chosen based on desired strength and compliance characteristics of the implant.

At603, one or more filaments are stitched into a substrate to form the nonuniform stitching pattern and form the soft tissue implant. If the substrate includes two or more layers of material, the filament(s) may be stitched into two or more of the layers. The substrate may be made of a biotextile or a medical textile, as described herein. The one or more filaments may be stitched in a lock-stitch configuration to form the nonuniform stitch pattern on a first side of the implant and a reverse stitch pattern on a second (opposite) side of the implant. The first side of the implant with the nonuniform stitch pattern may have a smoother surface contour and may include less filament surface area than the second side of the implant.

At605, the implant is optionally tested for strength and/or compliance. In some examples, a uniaxial tensile testing procedure is performed, an example of which is described in U.S. Pat. No. 10,426,587, which is incorporated by reference in its entirety herein. The testing may be used to verify that a particular nonuniform stitching pattern imparts desirable tensile strength and compliance characteristics to an implant. Once verified, the nonuniform stitching pattern may be used in the manufacturer of soft tissue implants.

Once the implant is fabricated, the implant may be implanted into a patient's body in a particular orientation. For example, the first side of the implant with the nonuniform stitching pattern may be positioned nearer to one or more tissue types (e.g., organs) compared to the opposing second side with the reverse stitching pattern. Once implanted, the substrate and the embroidered filament can bear the load of tensile forces applied by the patient's tissues and the implant can comply as needed.

It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.