WO2025014780A1

WO2025014780A1 - Containment devices for bone graft

Info

Publication number: WO2025014780A1
Application number: PCT/US2024/036809
Authority: WO
Inventors: Keyvan Behnam; Joseph M. Hernandez
Original assignee: Biomet Biologics LLC
Current assignee: Biomet Biologics LLC
Priority date: 2023-07-12
Filing date: 2024-07-03
Publication date: 2025-01-16
Anticipated expiration: 2026-01-12

Abstract

A containment device (102, 104) may include one or more filaments formed as a mesh (126) having a Leno weave, wherein the mesh forms a plurality of pores (128). The containment device may include a bone graft material (108) having a substantially uniform shape and size contained by the mesh. Each of the plurality of pores formed by the mesh has a maximum opening that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material.

Description

CONTAINMENT DEVICES EOR BONE GRAFT

CLAIM OF PRIORITY

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/526,346, filed on July 12, 2023, the benefit of priority of which is claimed hereby, and which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to bone grafts and, more specifically, to bone grafts containing synthetic material such as particles.

BACKGROUND

[0003] In orthopedic applications, it can be important to improve or create bone for implantation of orthopedic devices such as orthopedic implants. Bone loss can occur such that bone must be improved for fixation of the orthopedic implants. Conventionally, bone regeneration is achieved by filling a site that has bone loss with a bone graft. Over time, the bone graft is incorporated by the host and new bone remodels the bone graft. Existing methods of improving bone include using a bone graft material such as allografts, autografts and synthetic grafts. Carriers can be added to bone graft material. However, most carriers are added by direct mixing with the bone graft material and are designed to give the bone graft material a thicker consistency. Such carriers include lecithin, collagen, carboxymethylcellulose and other hydrogels Recently, bone grafts using a biocompatible resorbable mesh have been developed but these designs can be improved.

OVERVIEW

[0004] It is desirable from an osteointegration standpoint that bone graft material be substantially uniform in size and shape. However, there exists a need for a bone graft containment device that can accommodate substantially uniformly sized and shaped bone graft material such as substantially spherical synthetic particles. Typically, allograft based products are manufactured by milling and have a wide distribution of particle sizes (e.g., 100 microns to 850 microns). As such, the particles when placed inside a mesh container aggregate in a way where larger irregular particles tend to migrate outward and can close off the pores of the container. This closure of the pores keeps the smaller particles contained.

However, closing off the pores can discourage infiltration of autograft cells. Alternatively, if larger particles shift position, smaller particles can migrate from the mesh bag such as during manufacturing, packaging or interoperative handling. The present inventors propose a bone graft with a mesh container that effectively contains substantially uniformly sized and shaped bone graft material such as spherical synthetic particles.

[0005] Additionally, the present inventors propose the mesh container can be configured (shaped and sized) to allow for more effective and efficient mixing of autograft with the contents within the container. More particularly, the present bone grafts do not require the physician to open and/or seal compartments of the container. Additionally, the physician does not have to fill the graft with material during the procedure. The result is reduced procedure times and more effective mixing of the autograft with the contents of the container. More particularly, the bone graft of the present application can have the container with one or more infiltration features such as invaginations formed by spot welds or otherwise features in desired locations along its length. These infiltration features for the container can form reservoirs or receptacles for initial placement of autograft on the outside of the container in a way that allows the autograft to more effectively infiltrate and mix with the bone graft material within the container.

[0006] The present inventors propose the bone graft with the mesh carrier can have a bone conforming yet semi-rigid shape. The carrier can be formed of polymer or other filaments woven as a mesh that forms pores. The present inventors have determined that the size of each the pores can have a maximum opening of that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material that is contained within the carrier. As an example, for spherical particles having a 750 micron diameter, the mesh carrier can form pores of substantially 400 microns (e.g., 55% smaller) in size. This pore size to bone graft material size percentage has been found to effectively contain the allograft material with a uniform shape and size during manufacturing, packaging and interoperative transport.

[0007] The present inventors propose the mesh forming the container be woven according to the Leno technique. This type of weave (Leno weave) has been determined to effectively reinforce individual pores to prevent them from stretching further such as when tensile force is applied to the container. The mesh carrier can be formed of individual filaments or groups of filaments that are woven according to other technique, are braided or knitted. Portions of the container may not be woven or can have a modified weave according to some examples.

[0008] To better illustrate the containers and methods disclosed herein, a non-limiting list of examples, is provided here:

[0009] In Example 1, a container configured to form a bone graft optionally including: one or more filaments formed as a mesh having a Leno weave, wherein the mesh forms a plurality of pores; a bone graft material having a substantially uniform shape and size contained by the mesh, wherein each of the plurality of pores has a maximum opening that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material.

[0010] In Example 2, the container of Example 1, wherein optionally the maximum opening is substantially 55% smaller than the minimum dimension of the bone graft material.

[0011] In Example 3, the container of any one or any combination of Examples 1-2, wherein optionally the bone graft material includes a plurality of spherical particles.

[0012] In Example 4, the container of Example 3, wherein optionally one or more of the plurality of spherical particles are hollow and have a hole therein configured to receive cells from autograft.

[0013] In Example 5, the container of any one or any combination of Examples 1-4, further optionally including one or more infiltration features having a desired position along the container relative to at least one of a first end or a second end thereof.

[0014] In Example 6, the container of Example 5, wherein optionally the first end and the second end are formed by at least one of a woven seal or an ultrasonic thermal seal.

[0015] In Example 7, the container of any one or combination of Examples

5-6, wherein optionally the one or more infiltration features are one or more spot welds of the one or more filaments.

[0016] In Example 8, the container of Example 7, wherein optionally the container at the one or more infiltration features has a thickness of between 0.001 mm and 1.0 mm.

[0017] In Example 9, the container of any one or combination of Examples

6-8, wherein optionally the one or more infiltration features contour a surface of the container to form one or more receptacles configured to receive autograft.

[0018] In Example 10, the container of any one or combination of Examples 6-8, wherein optionally the one or more infiltration features have a diameter of between 1.5 mm and 4.5 mm and are spaced in increments of between 20 mm and 40 mm from at least one of the first end or the second end.

[0019] In Example 11, a container configured to form a bone graft optionally including: a first end; a second end opposing the first end; one or more filaments formed as a mesh, wherein the mesh forms a plurality of pores; a bone graft material contained by the mesh; and one or more infiltration features having a desired position along the container relative to at least one of the first end or the second end.

[0020] In Example 12, the container of Example 11, wherein optionally the one or more infiltration features are one or more spot welds of the one or more filaments.

[0021] In Example 13, the container of any one or combination of Examples 11-12, wherein the container at the one or more infiltration features has a thickness of between 0.001 mm and 1.0 mm. [0022] In Example 14, the container of any one or combination of Examples 11-13, wherein optionally the one or more infiltration features contour a surface of the container to form one or more receptacles configured to receive autograft.

[0023] In Example 15, the container of any one or combination of Examples 11-14, wherein optionally the one or more infiltration features have a diameter of between 1.5 mm and 4.5 mm and are spaced in increments of between 20 mm and 40 mm from at least one of the first end or the second end.

[0024] In Example 16, the container of any one or combination of Examples 11-15, wherein optionally the one or more filaments formed as a mesh having a Leno weave and each of the plurality of pores has a maximum opening that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material.

[0025] In Example 17, the container of any one or combination of Examples 11-16, wherein optionally the bone graft material includes a plurality of spherical particles, and wherein one or more of the plurality of spherical particles are hollow and have a hole therein configured to receive cells from autograft.

[0026] In Example 18, a method of bone grafting optionally including: implanting onto bone a mesh container with a bone graft material carried thereby, wherein the mesh container includes one or more infiltration features having a desired position along the mesh container relative to at least one of a first end or a second end of the mesh container; and positioning autograft over a surface of the mesh container at and adjacent the one or more infiltration features in a receptacle created thereby.

[0027] In Example 19, the method of Example 18, wherein optionally the mesh container is formed with a Leno weave and has a plurality of pores, wherein the plurality of pores has a maximum opening that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material.

[0028] In Example 20, the method of any one or combination of Examples 18-19, wherein the mesh container at the one or more infiltration features has a thickness of between 0.001 mm and 1.0 mm, and wherein the one or more infiltration features have a diameter of between 1.5 mm and 4.5 mm and are spaced in increments of between 20 mm and 40 mm from at least one of the first end or the second end of the mesh container.

[0029] In Example 21 the container and the method of any one or any combination of Examples 1-20 can optionally be configured such that all elements, operations, or other options recited are available to use or select from.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

[0031] FIG. l is a plan view of a delivery system for forming a bone graft including a first container and a second container of differing sizes according to an example of the present application.

[0032] FIG. 1A is a cross-sectional view of the first container of FIG. 1, the cross-section passing through an infiltration feature that forms a receptacle of the first container.

[0033] FIG. 2 is an enlarged plan view of a portion of the second container of FIG. 1 showing a mesh of one or more filaments containing a bone graft material such as a plurality of spherical synthetic particles according to an example of the present application.

[0034] FIG. 3 is an enlarged plan view of the mesh of FIG. 2 showing a Leno weave utilized according to one example.

[0035] FIG. 4 is an example of one of the spherical synthetic particles according to an example of the present application.

[0036] FIG. 4A is a cross-sectional view of an interior of the spherical synthetic particle of FIG. 4 according to an example of the present application.

[0037] FIG. 5 is a perspective view of another example of a container for forming a bone graft according to another example of the present application.

[0038] FIG. 6 illustrates a method of bone grafting using a container such as those constructed in accordance with at least one example. [0039] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

DETAILED DESCRIPTION

[0040] Disclosed herein is a container and method for forming a bone graft. As outlined in the OVERVIEW section and described in further detail below, the container can include numerous configurations. These configurations are exemplary in nature and are not intended to limit the spirit and scope of the present disclosure. Thus, numerous other configurations are also contemplated.

[0041] FIG. 1 is a plan view of a delivery system 100 for forming a bone graft including a first container 102 and a second container 104. The first container 102 has a length LI that differs from a length L2 of the second container 104. The first container 102 and the second container 104 can have a similar widths W 1.

[0042] As shown in FIG. 1, the first container 102 and the second container 104 can include a carrier 106 such as by one or more filaments formed as a mesh (see FIGS. 2 and 3), a bone graft material 108, a first end 110, a second end 112 and one or more infiltration features 114.

[0043] As shown in FIG. 1, the carrier 106 can form a bag to receive and retain the bone graft material 108 therein. The bone graft material 108 can be synthetic particles that are substantially uniformly shaped and sized. Thus, the synthetic particles can have a same shape and size according to some examples. As used herein the terms “substantially”, “about”, “similar”, “approximately”, “adjacent” and similar terms mean ± 10% or less of the value provided such as ± 10% or less of a size dimension, ± 10% or less of a shape, etc. Thus, some small variation in the particle size and shape due to manufacturing tolerances is contemplated. However, the intent of the present carrier 106 is to receive and retain particles of a similar size and shape. This should be contrasted with traditional bone graft material, which has a wide distribution of particle sizes (e g., 100 microns to 850 microns).

[0044] The first container 102 and the second container 104 can have particular functions or forms such as porosity, flexibility, strength, or stiffness as desired. The carrier 106 can be treated with films or coatings to produce a desired surface chemistry, texture, or drug elution to promote, speed up, slow down, or inhibit soft tissue and/or bone tissue growth. The coatings can be formulated to provide wear resistance, non-stick, hydrophilic/hydrophobic, low friction, dielectric/conductive or corrosion resistant surface properties.

[0045] The bone graft material 108 can be synthetic, being formed of a biodegradable polymer such as but not limited to: poly(ethylene glycol) (PEG), biodegradable polyester (poly(lactic acid) (PLA), poly(glycolic acid) (PGA), poly(lactic-co-glycolic acid) (PLGA), polylactide, or polyhydroxyalkanoate (polyhydroxybutyrates and polyhydroxyvalerates and copolymers). Other synthetic materials include composites, ceramics, ceramics with calcium, phosphates with calcium sulfates, coated metal particles, or the like are also contemplated.

Additionally, the bone graft material 108 can be derived from naturally occurring materials, and therefore, can be a bone derived material such as allograft bone, processed bone fragments, collagen, or the like. The bone graft material 108 can also include one morphogenic proteins (BMPs), growth factors, antibiotics, angiogenesis promoting materials, bioactive agents, or other actively releasing materials as known in the art.

[0046] The first end 110 can oppose the second end 112 along the longitudinal length. The second end 112 or the first end 110 can be formed after filling of the carrier 106 with the bone graft material 108. The first end 110 and/or the second end 112 can be formed by ultrasonic thermal sealing, woven sealing or another suitable technique. The length LI can be between 90 mm and 110 mm, for example. The length L2 can be between 40 mm and 60 mm. The width W 1 can be between 20 mm and 30 mm. However, other dimensions as suitable to address bone loss needs in different areas of the body are contemplated. Because every bone graft procedure can have different containment needs, the size and shape of the first and second containers 102, 104 is merely exemplary and not intended to be limiting. Because the first container 102 and the second container 104 can be utilized in different anatomical locations, they can be configured with the carrier 106 to be semi-rigid to allow for some degree of flexing/shape change to conform to the bone at the surgical site.

[0047] The one or more infiltration features 114 can be invaginations along a top surface of the carrier 106 and can have a desired position along the first container 102 and the second container 104 relative to at least one of the first end 110 or a second end 112 thereof. As an example, the one or more infiltration features 114 can be one or more spot welds 116 of the one or more filaments that form the carrier 106. However, other examples contemplate that the one or more infiltration features 114 can be a woven seal, ultrasonic thermal seal, one or more apertures, areas of having a different weave or filament type from a remainder of the carrier 106, or the like. The one or more infiltration features 114 can form regions of reduced thickness in the first container 102 and the second container 104 as further discussed and illustrated in reference to FIG. 1A. The one or more infiltration features 114 can be circular in shape. However, other geometry is contemplated. The one or more infiltration features 114 can have a diameter of between 1.5 mm and 4.5 mm and can be spaced in increments of between 20 mm and 40 mm from one another and/or from at least one of the first end 110 or the second end 112. The one or more infiltration features 114 can be generally centrally located with regard to the width W 1.

[0048] FIG. 1A shows a cross-section of the first container 102 along one of the one or more infiltration features 114. FIG. 1 A shows a thickness of the first container 102 including an edge thickness Tl. As shown in FIG. 1A, the first container 102 at the infiltration feature 114 has a thickness of between 0.001 mm and 1.0 mm. A thickness of zero at the infiltration feature 114 is also contemplated where the infiltration feature 114 is an aperture, according to other examples. The one or more infiltration features 114 act to contour a top surface 118 and a bottom surface 120 of the first container 102 to form a receptacle 122 or bowl configured to receive autograft or other material that can be layered or positioned on the top surface 118 and/or the bottom surface 120 by the physician during the procedure. The receptacle 122 can have a generally concave shape, for example. The thickness T1 can be between 5 mm and 15 mm, according to one example.

[0049] FIGS. 2 and 3 show enlarged views of a portion of the second container 104. As shown in FIGS. 2 and 3, the carrier 106 is shown as including one or more filaments 124 (best shown in FIG. 3) formed as a mesh 126. The one or more filaments 124 can be polymers such as poly ether ether ketone (PEEK), polyethelene, poly(methyl methacrylate) (PMMA), polyester, polytetrafluoroethylene (PTFE), resorbable materials such as poly-L-lactide (PLLA), polyglycolic acid (PGA), hydrogels or metals, such as stainless steels, titanium, titanium alloys, and nitinol. However, other materials such as collagen based suture, biocompatible textile, and/or tissue derived filaments or the like are also contemplated. The one or more filaments 124 described above can be coated with other materials either before being formed or after the weaving takes place. The coatings can perform functions such as inducing bone growth or retarding soft tissue growth. In various examples, the coatings can add strength, increase durability and bioabsorbability, provide a desired porosity, or allow for setting of a desired flexible containment device shape. In one exemplary application, one or more coatings inducing bone growth can be located on a bone facing surface of the flexible containment device and one or more coatings inducing soft tissue or bone growth.

[0050] As shown in FIG. 3, the mesh 126 can have a Leno weave according to the example of FIGS. 2 and 3. The mesh 126 can form a plurality of pores 128, which are formed by gaps between the mesh 126. One or more or substantially all of the plurality of pores 128 can have a maximum opening MOD that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material 108 (FIG. 2). Thus, the maximum opening MOD can be substantially 55% smaller than the minimum dimension of the bone graft material 108 (FIG. 2). Because of the uniform shape and size of the bone graft material 108, the percentage range of the maximum opening MOD to the minimum dimension of the bone graft material 108 (FIG. 2) can retain the bone graft material 108 within the carrier 106. [0051] FIG. 2 shows the bone graft material 108 as synthetic spherical particles 108A. However, other shapes such as, but not limited to: oval, cube, rectangular, cone, and cylinder, square, prism, pyramid, etc. are contemplated.

[0052] FIGS. 4 and 4A show one of the synthetic spherical particles 108A in further detail. The spherical particle 108A can include a hole 130 therein. The hole 130 forms an opening between an interior and the exterior. The hole 130 can be sized to receive one or more cells from autograft, for example. As best shown in FIG. 4A, the spherical particle 108A can comprise a shell with a hollow interior 132 that communicates with the exterior via the hole 130. However, other examples contemplate the spherical particle 108A may not comprise a shell in configuration. [0053] FIG. 5 shows a third container 134 having a construction similar to that of the first container and the second container discussed previously. The third container 134 has an increased longitudinal length and at least three infiltration features 114A, 114B and 114C, which form the receptacles as previously discussed. [0054] FIG. 6 is a diagram of a method 200 of bone grafting. The method 200 at step 202 can include implanting onto bone a mesh container with a bone graft material carried thereby. The mesh container can include one or more infiltration features having a desired position along the mesh container relative to at least one of a first end or a second end of the mesh container. The method 200 at step 204 can include positioning autograft over a surface of the mesh container at and adjacent the one or more infiltration features in a receptacle created thereby.

[0055] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0056] In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls.

[0057] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0058] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

WHAT IS CLAIMED IS:

1. A container configured to form a bone graft comprising: one or more filaments formed as a mesh having a Leno weave, wherein the mesh forms a plurality of pores; a bone graft material having a substantially uniform shape and size contained by the mesh, wherein each of the plurality of pores has a maximum opening that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material.

2. The container of claim 1, wherein the maximum opening is substantially 55% smaller than the minimum dimension of the bone graft material.

3. The container of any one of claims 1-2, wherein the bone graft material comprises a plurality of spherical particles.

4. The container of claim 3, wherein one or more of the plurality of spherical particles are hollow and have a hole therein configured to receive cells from autograft.

5. The container of any one of claims 1-4, further comprising one or more infiltration features having a desired position along the container relative to at least one of a first end or a second end thereof.

6. The container of claim 5, wherein the first end and the second end are formed by at least one of a woven seal or an ultrasonic thermal seal.

7. The container of any one of claims 5-6, wherein the one or more infiltration features are one or more spot welds of the one or more filaments.

8. The container of claim 7, wherein the container at the one or more infiltration features has a thickness of between 0.001 mm and 1.0 mm.

9. The container of any one of claims 6-8, wherein the one or more infiltration features contour a surface of the container to form one or more receptacles configured to receive autograft.

10. The container of any one of claims 6-9, wherein the one or more infiltration features have a diameter of between 1.5 mm and 4.5 mm and are spaced in increments of between 20 mm and 40 mm from at least one of the first end or the second end.

11. A container configured to form a bone graft comprising: a first end; a second end opposing the first end; one or more filaments formed as a mesh, wherein the mesh forms a plurality of pores; a bone graft material contained by the mesh; and one or more infiltration features having a desired position along the container relative to at least one of the first end or the second end.

12. The container of claim 11, wherein the one or more infiltration features are one or more spot welds of the one or more filaments.

13. The container of any one of claims 11-12, wherein the container at the one or more infiltration features has a thickness of between 0.001 mm and 1.0 mm.

14. The container of any one of claims 11-13, wherein the one or more infiltration features contour a surface of the container to form one or more receptacles configured to receive autograft.

15. The container of any one of claims 1 1-14, wherein the one or more infiltration features have a diameter of between 1.5 mm and 4.5 mm and are spaced in increments of between 20 mm and 40 mm from at least one of the first end or the second end.

16. The container of any one of claims 11-15, wherein the one or more filaments formed as a mesh having a Leno weave and each of the plurality of pores has a maximum opening that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material.

17. The container of any one of claims 11-16, wherein the bone graft material comprises a plurality of spherical particles, and wherein one or more of the plurality of spherical particles are hollow and have a hole therein configured to receive cells from autograft.

18. A method of bone grafting comprising: implanting onto bone a mesh container with a bone graft material carried thereby, wherein the mesh container includes one or more infiltration features having a desired position along the mesh container relative to at least one of a first end or a second end of the mesh container; and positioning autograft over a surface of the mesh container at and adjacent the one or more infiltration features in a receptacle created thereby.

19. The method of claim 18, wherein the mesh container is formed with a Leno weave and has a plurality of pores, wherein the plurality of pores has a maximum opening that is substantially 45% - 65% smaller than a minimum dimension of the bone graft material.

20. The method of any one of claims 18-19, wherein the mesh container at the one or more infiltration features has a thickness of between 0.001 mm and 1.0 mm, and wherein the one or more infiltration features have a diameter of between 1.5 mm and 4.5 mm and are spaced in increments of between 20 mm and 40 mm from at least one of the first end or the second end of the mesh container.