Methods for forming bone grafts

Abstract

Disclosed are methods for forming a bone graft by rolling a bundle of demineralized bone fibers to form a bone graft material with increased flexural strength.

Description

090129-795625METHODS FOR FORMING BONE GRAFTSField of the Disclosure

[0001] This application relates to bone grafts and more specifically, to methods for forming a bone graft into a rolled bone fiber article to facilitate increased flexural strength.Background

[0002] Bone grafts are used to repair and replace damaged bone or fuse bones to reduce pain. The procedure of bone grafting promotes a body’s natural bone-making process by applying the grafts in weak, broken or deficient bones for added support. This can stimulate tissue growth, bridge gaps, and restore bone rigidity and strength. It can act as a scaffold for new bone growth, providing structure for cells to attach and migrate.

[0003] Bone grafts are used in procedures in numerous medical fields. These fields include dental surgery, orthopedic trauma surgery, spinal surgery, joint reconstruction, congenital surgery, and other corrective orthopedic procedures.

[0004] Bone grafts according to the current disclosure are composed of demineralized bone fibers and may be formed by a wet lay process in which the fibers are suspended in a fluid prior to being laid in a mold. However, the wet lay process may be inefficient and ineffective, particularly for bone grafts requiring significant bending strength that are long, narrow, and / or thin. A need exists for methods to form bone grafts with significant bending strength and to avoid breakage when formed into long, narrow, and / or thin shapes.Summary

[0005] Methods for forming a bone graft from a rolled bone fiber article, to provide improved flexural strength of the graft are provided. Further modifications to the rolled bone fiber article are also presented and allow creation of forms of various shapes and dimensions.1105656448 1090129-795625

[0006] In one aspect, the present disclosure provides a method of forming a bone graft. The method includes arranging a plurality of demineralized bone fibers in a substantially parallel orientation along a longitudinal axis to form a demineralized bone fiber arrangement having a length, positioning the length of the demineralized bone fiber arrangement in a fiber rolling device, and rolling the length of the demineralized bone fiber arrangement using the fiber rolling device to form a rolled bone fiber article. The method also includes maintaining the rolled bone fiber article for a time to allow it to be subjected to one or more conditions sufficient for the rolled bone fiber article to maintain its shape. The method may further include transferring the rolled bone fiber article into a cavity of a mold, the cavity defining a mold shape, moistening the rolled bone fiber article to induce expansion of the rolled bone fiber article within the cavity, and maintaining the rolled bone fiber article in the cavity for a time and one or more conditions sufficient for the rolled bone fiber article to conform to the mold shape and to maintain the mold shape when removed from the cavity of the mold.

[0007] In another aspect, a use of a fiber rolling device to prepare a plurality of demineralized bone fibers for formation as a bone graft is provided. The use includes preparing or having prepared a plurality of demineralized bone fibers by arranging the demineralized bone fibers in a substantially parallel orientation along a longitudinal axis, wherein the arrangement of demineralized bone fibers defines a length. The use also includes positioning the length of fibers in a fiber rolling device operable to roll the fibers into a rolled bone fiber article, thereby entangling the bone fiber fibers and preparing the rolled bone fiber article for molding in a form of a molded bone graft.

[0008] In another aspect, a method of repairing a bone defect or bone injury in a subject in need thereof is provided. The method includes implanting a bone graft including a plurality of entangling demineralized bone fibers.

[0009] In another aspect, any one or more aspects or features described herein may be combined with any one or more other aspects or features for additional advantage.2105656448 1090129-795625

[0010] Other aspects will be apparent from the detailed description and accompanying drawings.

[0011] Those skilled in the art will appreciate the scope of the present disclosure and realize additional aspects thereof after reading the following detailed description of the preferred aspects in association with the accompanying drawing figures.Brief Description of the Drawings

[0012] Figures 1A and 1 B are top and side views of schematics of bone grafts formed using a wet lay method as known in the prior art.

[0013] Figure 2 is a perspective view of a schematic of a bone graft as shown in Figures 1A and 1 B, the bone graft being subjected to applied forces.

[0014] Figure 3 is a top view of a schematic of molds including cavities for forming bone grafts using the wet lay method.

[0015] Figures 4A-4D are top views of schematics of bone grafts formed using the mold cavities shown in Figure 3.

[0016] Figures 5 is a perspective view of rolled bone fiber articles formed using a rolling method then placed into a mold for use in forming a bone graft according to one or more aspects of the present disclosure.

[0017] Figures 6A and 6B are perspective views of rolled bone fiber articles formed using a rolling method then placed into a mold for use in forming a bone graft according to one or more aspects of the present disclosure.

[0018] Figure 7 is a schematic of a method for forming a bone graft by creating a rolled bone fiber article according to one or more aspects of the present disclosure.Detailed Description

[0019] The various aspects set forth below represent the necessary information to enable those skilled in the art to practice the disclosed methods. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and3105656448 1090129-795625 will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.

[0020] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0021] It will be understood that when an element such as a layer, region, or substrate is referred to as being "on" or extending "onto" another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or extending "directly onto" another element, there are no intervening elements present. Likewise, it will be understood that when an element such as a layer, region, or substrate is referred to as being "over" or extending "over" another element, it can be directly over or extend directly over the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly over" or extending "directly over" another element, there are no intervening elements present. It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0022] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element, layer, or region to another element, layer, or region as illustrated in the Figures. It will be understood that these terms and those discussed above4105656448 1090129-795625 are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures.

[0023] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0024] The term “fiber rolling device” refers to a device intended to roll bone graft material into a rolled bone fiber article, as disclosed herein. A fiber rolling device may be selected from any of various devices known to be useful for rolling other types of fibrous material, such as rolling devices used for rolling tobacco for cigarettes or cigars; textile rolling machines; devices customized for medical-grade bone fiber handling; or any other device configured in such a way as to be capable of rolling bone graft material into a rolled bone fiber article, as described herein.

[0025] As used herein, the term “demineralized bone fibers” refers to elongate, filamentous structures derived from cortical, cancellous, or corticocancellous bone that has been subjected to a demineralization process, such as treatment with an acid solution, sufficient to remove at least a substantial portion of the inorganic mineral content (e.g., calcium phosphates) while retaining collagen, non-collagenous proteins, and other organic components of the bone matrix. The fibers may be arranged in random, aligned, or substantially parallel orientations, and may be compacted, rolled, or otherwise formed into sheets, cylinders, plugs, strips, or molded constructs for use in bone graft applications.

[0026] The term “demineralized bone fibers” encompasses any processed bone-derived material that retains osteoinductive potential and that is suitable for implantation into a bone defect or surgical site to promote new bone5105656448 1090129-795625 formation. The term "substantially parallel orientation" is understood to mean an arrangement where the longitudinal axes of most of the demineralized bone fibers are aligned generally in the same direction, along a common longitudinal axis, such that the fibers collectively define a fiber arrangement having a length.

[0027] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0028] Demineralized bone fibers (DBF) are a variant of demineralized bone matrix (DBM) that offer improved handling characteristics. Compared to particulate DBM which is produced by grinding and sieving cortical bone, DBF are elongated particles produced by milling cortical bone. This processing imparts natural cohesion and entanglement capability to the graft material. DBF also demonstrate superior osteoconductive properties compared to DBM particulate in rabbit models of posterolateral spine fusion. Thus, DBF are highly useful in orthopedic and spine surgery to promote new bone formation. Without intending to be bound by theory, it is believed that DBF offer superior osteoconductivity by providing a scaffold for cell migration.

[0029] Any DBF can be used. Various DBF are known and commercially available from various companies such as Stryker, DePuy Synthes, and Medtronic. Typically DBF are created from allogeneic (donor) cortical bone, demineralized to expose bone morphogenetic proteins, and provide a physical scaffold for new bone growth while offering osteoconductive potential to recruit and stimulate bone-forming cells. DBF are typically moldable, rapidly rehydratable with a saline or biological fluid, and sterilized. Fibrant Fibers (FF) available from ISTO Biologies are an advanced DBF option, distinguished by the fiber geometry and a patented manufacturing process.6105656448 1090129-795625

[0030] Yet a challenge has remained for preparing DBF as bone grafting material. A wet lay process is not very inefficient and can be ineffective for providing bone grafts requiring significant bending strength that are long, narrow, and / or thin. The present disclosure addresses this need by providing methods for forming a bone graft from a rolled bone fiber article, to facilitate increased flexural strength.

[0031] Figures 1 A and 1 B are top views of variations of a bone graft 100 formed using a wet lay method. Bone grafts are generally composed of fibers, such as bone fibers. Bone grafts may have a thickness of approximately 8 mm and a width of approximately 25 mm in order to minimize the risk of breakage of the bone graft.

[0032] The bone graft 100 is composed of demineralized bone fibers, a bone fiber suitable for bone grafts that are long, narrow, and / or thin. Figure 1A shows variations of the bone graft 100 having a thickness of approximately 7 mm and a width of approximately 8 mm. Figure 1 B shows variations of the bone graft 100 having a thickness of approximately 4 mm and a width of approximately 12 mm. The wet lay method includes suspending the fibers in a fluid prior to being laid in a mold. As shown in Figures 1A and 1 B, forming the bone graft 100 using the wet lay method may lead to increased breakage of the bone graft 100 due to misaligned fibers.

[0033] Figure 2 is a perspective view of the bone graft 100 being subjected to applied forces. As shown in Figure 2, the bone graft 100 formed using the wet lay method may be more flimsy and / or have frayed edges when subjected to applied forces. Additionally, the bone graft 100 formed using the wet lay method may lose integrity when rehydrated, leading to breakage.

[0034] Figure 3 is a top view of variations of a mold 150 including one or more cavities 152 for forming bone grafts, such as the bone graft 100, using the wet lay method as known in the prior art. The mold 150A has cavities 152A having a thickness of approximately 8 mm, a width of approximately 8 mm, and a length of approximately 15 cm. The mold 150B has cavities 152B having a thickness of7105656448 1090129-795625 approximately 5 mm, a width of approximately 12 mm, and a length of approximately 15 cm.

[0035] When wet laying the bone graft 100 into each of the cavities 152 of the mold 150, the fibers of adjacent bone grafts may overlap the bars separating the adjacent cavities 152 to create a misaligned fiber orientation. This fiber overlap may cause a drag effect that prevents the fibers from contouring evenly in the cavities 152 of the mold 150, resulting in bone grafts that have an increased brittleness. Additionally, inserting additional separators between adjacent cavities 152 may be time intensive, requiring liquid to be added separately to each cavity 152 as part of the wet lay method, and may still result in bone grafts with misaligned fibers and thereby an increased brittleness.

[0036] Figures 4A-4D are top views of variations of the bone graft 100 formed using the cavities 152 of the mold 150 in the wet lay method. As shown in Figures 4A-4D, the bone grafts 100 formed using the wet lay method have misaligned fibers (e.g., fibers with a random orientation). Additionally, as shown in Figure 4D, the bone grafts 100 formed using the wet lay method may be difficult to separate due to fiber overlap between adjacent cavities 152.

[0037] Figure 5 is a perspective view of variations of a rolled bone fiber article 200 formed using a rolling method for use in forming a bone graft. The rolled bone fiber article 200 may be formed using a fiber rolling device. For example, demineralized bone fibers may be arranged in a substantially linear orientation to form a demineralized bone fiber arrangement. The demineralized bone fiber arrangement may have a length to be positioned in the fiber rolling device for rolling the demineralized bone fiber arrangement into a rolled bone fiber article.

[0038] In some aspects, arranging a plurality of demineralized bone fibers in a substantially parallel orientation along a longitudinal axis to form a demineralized bone fiber arrangement having a length includes positioning the length of the demineralized bone fiber arrangement in a fiber rolling device; rolling the length of the demineralized bone fiber arrangement using the fiber rolling device to form a rolled bone fiber article; and maintaining the rolled bone fiber8105656448 1090129-795625 article for a time and subject to one or more conditions sufficient for the rolled bone fiber article to maintain its shape.

[0039] Figures 6A and 6B are perspective views of variations of the rolled bone fiber article 200 formed using the rolling method. The rolled bone fiber article 200 may have a length of approximately 15 cm and a diameter between approximately 1 mm and 50 mm. In some aspects, the rolled bone fiber article 200 may have a diameter of approximately 7.5 mm. When molded into a bone graft, the rolled bone fiber article 200 may form a bone graft having a length of approximately 15 cm and a width of approximately 9 mm.

[0040] Following formation of the rolled bone fiber article 200, non- aligned fibers may be wrapped around the periphery of the rolled bone fiber article 200. The rolled bone fiber article 200 may be subjected to specific conditions, such as heat and / or freeze-drying, to maintain the rolled shape. When creating the rolled bone fiber article 200 to form a bone graft, the rolled bone fiber article 200 may be placed in a cavity of a mold, such as the cavities 152 of the mold 150. Once placed in the cavity, the rolled bone fiber article 200 may be rehydrated, such as by using a squirt bottle to spray the rolled bone fiber article 200 with water. As the rolled bone fiber article 200 rehydrates, it may swell to fit the shape of the cavity. The rolled bone fiber article 200 may then be manually molded into the shape of the cavity. In some aspects, the rolled bone fiber article 200 may be reworked once in the cavity of the mold if the fibers did not maintain the necessary structural integrity (e.g., the necessary linear alignment) when transferred to the cavity in order to better align the fibers.

[0041] Figure 7 is a schematic of a method 300 of rolling fibers to form a bone graft by creating a rolled bone fiber article, such as, but not limited to, the rolled fiber article 200. The method 300 includes arranging 302 a plurality of demineralized bone fibers in a substantially parallel orientation along a longitudinal axis to form a demineralized bone fiber arrangement having a length and positioning 304 the length of the demineralized bone fiber arrangement in a fiber rolling device. The method also includes rolling 306 the length of the demineralized bone fiber arrangement using the fiber rolling device to form a rolled bone fiber9105656448 1090129-795625 article and transferring 308 the rolled bone fiber article into a cavity of a mold, the cavity defining a mold shape. The method further includes moistening 310 the rolled bone fiber article to induce expansion of the rolled bone fiber article within the cavity and maintaining 312 the rolled bone fiber article in the cavity for a time and one or more conditions sufficient for the rolled bone fiber article to conform to the mold shape and to maintain the mold shape when removed from the cavity of the mold. When removed, the rolled bone fiber article as molded to the cavity of the mold may be used as an implantable bone graft at a bone defect site and / or a bone injury site to repair a bone defect and / or a bone injury.Methods of forming bone grafts

[0042] The methods described herein of rolling fibers to form a bone graft by creating a rolled bone fiber article, such as, but not limited, the method 300, may facilitate improved controllability of bone graft shape. For example, the rolling process may allow for controllability of the length, diameter, density, and / or shape of the bone graft. The density of the bone graft may be controlled based on the quantity of fibers used to form the rolled bone fiber article. Additionally, the diameter of the rolled bone fiber article, and therefore the size of the bone graft, may be controlled based on the rolling technique used by the fiber rolling device.

[0043] In some aspects, arranging a plurality of demineralized bone fibers in a substantially parallel orientation along a longitudinal axis to form a demineralized bone fiber arrangement having a length involves initially preparing the bone fibers such that their elongated axes are oriented generally in the same direction. This arrangement may be achieved manually or by using one or more tools or devices specifically designed for the purpose. In some aspects, demineralized bone fibers can be separated into groups by sifting, combing, or shaking, and then manually arrayed on a flat surface or within a channel, trough, or alignment jig that encourages parallel positioning. Optionally, the aligned fibers may be gently compacted or combed to further improve the parallel arrangement prior to further processing, such as insertion into a fiber rolling device. Arranging10105656448 1090129-795625 the bone fibers in this manner is important for maximizing the structural integrity of the resulting graft

[0044] In some aspects, after the demineralized bone fibers are in a substantially parallel orientation, positioning the length of the demineralized bone fiber arrangement in a fiber rolling device follows. Positioning the length of the demineralized bone fiber arrangement in the fiber rolling device may be performed by placing the aligned bundle of fibers onto the rolling surface or mechanism of the device such that the full length of the arrangement is supported and ready to be rolled. In some aspects, the fiber arrangement may be placed parallel to the main axis or plane of the rolling device to ensure simultaneous and consistent rolling along the entire length. Depending on the configuration of the fiber rolling device, the arrangement may be placed directly onto a rolling mat, within a channel or trough, or between two planar surfaces designed to facilitate even rolling.

[0045] The length of the demineralized bone fiber arrangement positioned in the rolling device may be adjusted based on the intended final dimensions of the graft. For instance, longer arrangements may be used for producing strips intended for larger grafts or for subsequent segmentation into multiple smaller grafts after rolling. Also, the diameter and density of the resulting rolled article can be influenced by the amount of fiber introduced and the precision in positioning the arrangement within the rolling device. In some aspects, non- aligned or peripheral fibers may be positioned towards the outer edges of the arrangement prior to placement in the rolling device so that, upon rolling, they wrap around the core of the construct, further enhancing its cohesion and structural strength. Positioning the length of the demineralized bone fiber arrangement in the fiber rolling device is critical for achieving the desired form, mechanical strength, and workability of the rolled bone fiber article.

[0046] Rolling the length of the demineralized bone fiber arrangement using the fiber rolling device to form a rolled bone fiber article follows the positioning of the demineralized bone fibers. This rolling is an important aspect of the disclosed method for forming bone grafts, in which a pre-arranged length of demineralized bone fibers is loaded into a fiber rolling device and then rolled to11105656448 1090129-795625 produce a cohesive, entangled, and structurally robust rolled bone fiber article. The rolling device is designed to accept the longitudinally arranged bundle of demineralized bone fibers, and, through mechanical action, such as rotation or guided movement, roll the entire length to achieve the desired configuration. Device selection and adjustment, for example, control of rolling tightness or applied pressure, can further influence the density and diameter of the final product.

[0047] Once loaded, the fiber arrangement may be rolled along its length by the device, causing the fibers to become entangled and compacted into a cohesive mass. This rolling action may further align any stray or non-parallel fibers by wrapping them around the periphery of the cylindrical body, effectively binding the bundle and minimizing the presence of loose or fraying ends.

[0048] Next, maintaining the rolled bone fiber article for a time in order to subject to one or more conditions sufficient for the rolled bone fiber article to maintain its shape may involve maintaining the rolled bone fiber article in a mold. In some aspects, this mold usage is designed to ensure the structural integrity and desired form of the rolled bone fiber article. In some aspects, after the rolled bone fiber article is placed it the mold, it can be moistened to induce expansion. This may cause the fibers to swell and fill the mold cavity more effectively. In other aspects, the conditions of this step may include the application of heat and / or freeze-drying techniques. The heat treatment can facilitate the setting of the article’s shape by promoting the entanglement and bonding of the demineralized bone fibers. The freeze-drying can be employed to remove moisture from the rolled bone fiber article, preserving its form and preventing deformation during storage and handling. In other aspects, the rolled bone fiber article is not maintained in a mold, hydrated, heated, nor freeze-dried, but is subjected to other conditions.

[0049] Additionally, the methods described herein of rolling fibers to form a bone graft by creating a rolled bone fiber article, such as, but not limited, the method 300, may facilitate improved production efficiency. For example, the use of a fiber rolling device to form the rolled bone fiber articles may allow for simple assembly, disassembly, and cleaning (e.g., sanitization), such as for use in a clean room environment.12105656448 1090129-795625

[0050] The methods described herein of rolling fibers to form a bone graft by creating a rolled bone fiber article, such as, but not limited, the method 300, may allow for the formation of a bone graft that is long, narrow, and / or thin while maintaining significant bending strength to avoid breakage. For example, a rolled bone fiber article may be used to form a bone graft in a substantially rectangular shape with a defined thickness. That is, the bone graft may be formed in the shape of a strip. The strip may have a thickness of approximately 8 mm, a width of approximately 8 mm, and a length of approximately 15 cm. The strip may have a thickness of approximately 5 mm, a width of approximately 12 mm, and a length of approximately 15 cm. The strip may be used to repair a bone defect or injury at multiple locations within a body, such as, but not limited to, the spine for treatment of scoliosis. The rolled bone fiber article may also be used to form a bone graft having a different shape, such as, but not limited to, a rod and / or cylinder shape. This assists in maintaining the overall shape and reduces defects associated with fiber misalignment observed in wet lay methods

[0051] The methods described herein of rolling fibers to form a bone graft by creating a rolled bone fiber article, such as, but not limited, the method 300, may allow the bone fibers to entangle to form the rolled bone fiber article in the absence of a wrapping sheath. The entangled fibers forming the bone graft may facilitate an increased breakage resistance as compared to a bone graft composed of non-entangling fibers.

[0052] In some aspects, the rolled bone fiber article may be separated into rolled bone fiber article segments prior to being placed in the cavities of the mold. The segmentation of the rolled bone fiber article into segments may facilitate improved production efficiency of smaller bone grafts. In the process of forming the rolled bone fiber article segments, the rolled bone fiber article may be formed to have a lower density (e.g., composed of less fibers) as compared to the longer rolled bone fiber article discussed herein. For example, the rolled bone fiber article segments may be more rapidly rehydrated, due to their smaller size, and thus may require a lower density to maintain sufficient breakage strength. Production efficiency may further be improved by using uniformly dense fibers to13105656448 1090129-795625 form the rolled bone fiber article, thereby removing the need to weigh individual rolled bone fiber article segments. The rolled bone fiber article segments may be formed into specific shapes using the cavities of the mold.

[0053] In some aspects, the rolled bone fiber article may not be molded into a specific shape to be used as a bone graft. That is, the rolled bone fiber article may not be placed in a cavity of a mold prior to being used as a bone graft. Creating the rolled bone fiber article to form a bone graft without further molding may facilitate improved malleability and cohesiveness of the bone graft. Creating the rolled bone fiber article to form a bone graft may allow for the rolled article to be delivered to a bone graft site via a delivery tube. For example, creating a rolled bone fiber article to form a bone graft may increase the number of available surgical sites for bone graft insertion, due to the rolled bone fiber article being able to move through a tube to the bone graft site without compressing or breaking. At the bone graft site, the rolled bone fiber article may be rehydrated by tissue fluids, which may include osteogenic cells from the bone graft site. Creating the rolled bone fiber article to form a bone graft may allow for the rolled article to be inserted into a delivery tube for placement adjacent to hardware at the bone graft site to provide a contiguous matrix to encourage bone to bridge the fusion site.

[0054] In some aspects, the rolled bone fiber article may be cut into various lengths such that multiple bone grafts can be produced simultaneously.

[0055] In some aspects, the demineralized bone fibers may be used alone or in combination with other osteoconductive, osteoinductive, or osteogenic materials. Such materials may include, without limitation: (i) particulate bone (cortical, cancellous, or corticocancellous), in mineralized or demineralized form; (ii) bone chips, shavings, or powders; (iii) collagen or collagen-based matrices; (iv) ceramics such as hydroxyapatite, tricalcium phosphate, or biphasic calcium phosphate; (v) bioactive glasses; (vi) synthetic polymers, natural polymers, or composites thereof; and (vii) viable or processed cellular materials including bone marrow aspirate, mesenchymal stem cells, or other osteogenic cells.

[0056] The operational steps described in any of the aspects herein are described to provide examples and discussion. The operations described may14105656448 1090129-795625 be performed in numerous different sequences other than the illustrated sequences. Furthermore, operations described in a single operational step may actually be performed in a number of different steps. Additionally, one or more operational steps discussed in the various aspects may be combined.Repairing a bone

[0057] Another aspect of the present disclosure encompasses methods for repairing a bone or osteochondral defect in a subject. The method comprises implanting the bone graft at the site of a bone defect in a subject. Methods for repairing a bone or osteochondral defect in a subject include implanting a bone graft at the site of repair.(i) Types of defects

[0058] In accordance with aspects of this disclosure, any type of bone defect known in the art may be corrected using the bone graft of the disclosure.

[0059] Methods of bone grafts to repair a bone defect or an osteochondral defect are known in the art. It is appreciated that one skilled in the art would be able to select an appropriate method for implanting a bone graft for purposes of the present disclosure.

[0060] Suitable subjects may include animals in need of repair of a bone or osteochondral defect. In certain aspects, suitable subjects include humans. In other aspects, suitable subjects include companion animals or livestock animals.(ii) Possible Implantation Sites of a Bone Graft

[0061] The bone graft may be implanted at the site of a defect or an injury in a bone, cartilage, a ligament, a tendon, a meniscus, or a joint. In some aspects, a method of the present disclosure may encompass implanting bone graft as a scoliosis strip. The bone graft may also be implanted in order to fuse bones to reduce pain.

[0062] The devices described herein can also be used in spinal procedures and other orthopedic applications to deliver bone graft material to other locations in the body (for example, the femur or tibia).15105656448 1090129-795625

[0063] Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the principles and features disclosed herein. Various combinations and subcombinations of the various features described herein are possible.Examples

[0064] The following examples are included to demonstrate various aspects of the present disclosure. It should be appreciated by those of skill in the art that the techniques disclosed in the examples that follow represent techniques discovered by the inventors to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific aspects which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.Example 1:

[0065] Demineralized bone fibers were separated into longitudinally arranged fibers. These longitudinally arranged fibers were then placed into a fiber rolling device. By using the fiber rolling device to roll the longitudinally arranged fibers, the demineralized bone fibers were then further longitudinally arranged. This rolling process further wrapped any non-aligned fibers around the periphery of the then cylindrical shaped bone graft.

[0066] The rolling of the demineralized bone fibers resulted in the bone graft maintaining its shape more strongly than non-rolled bone grafts and allowed for easy placement directly into wet lay molds. The rolled demineralized bone fibers were placed into the mold cavities of various sizes, including 8 x 8 mm16105656448 1090129-795625 and 12 x 5 mm mold cavities. After being placed in the mold cavities, the rolled demineralized bone fibers may then be moistened by spraying with a liquid. As the rolled demineralized bone fibers became more hydrated, they swelled to fit within the cavity and were easily molded to the cavity shape. The bone grafts made during this method both simplified the mold loading process and improved the strength of the bone graft.Example 2:

[0067] The method of example 1 was performed to create rolled and molded bone grafts with increased structural strength. These bone grafts were then freeze dried. The freeze dried bone grafts herein disclosed exhibited surprising strength and allow for rehydration in the surgical site with tissue fluid. Example 3:

[0068] The method of example 1 was performed to create rolled and molded bone grafts with increased structural strength. In this process, the fiber rolling machine was configured to create low density rolled demineralized bone fibers. This lower density rolled demineralized bone fiber material is placed into long and thin mold, creating in one non-limiting aspect, a bone graft having approximately a 6 mm diameter. This bone graft is then segmented into a plurality of bone grafts, where in some non-limiting aspects, the segments are approximately 15 mm long by 6 mm in diameter.

[0069] Those skilled in the art will recognize improvements and modifications to the preferred aspects of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.17105656448 1

Claims

090129-795625ClaimsWhat is claimed is:1 . A method of forming a bone graft comprising: a. arranging a plurality of demineralized bone fibers in a substantially parallel orientation along a longitudinal axis to form a demineralized bone fiber arrangement having a length; b. positioning the length of the demineralized bone fiber arrangement in a fiber rolling device; c. rolling the length of the demineralized bone fiber arrangement using the fiber rolling device to form a rolled bone fiber article; and d. maintaining the rolled bone fiber article for a time and subject to one or more conditions sufficient for the rolled bone fiber article to maintain its shape.

2. The method of claim 1 , wherein the rolled bone fiber article comprises an implantable bone graft having increased flexural strength compared to a bone fiber article composed of unrolled demineralized bone fibers.

3. The method of claim 2, wherein the rolled bone fiber article can be cut into lengths such that multiple grafts can be produced simultaneously.

4. The method of claim 1 , wherein the rolled bone fiber article is rolled within a cover and maintained as a cylindrical article with a diameter of 1 -50 mm and a length of 1-1000 mm.

5. The method of claim 1 , further comprising: a. transferring the rolled bone fiber article into a cavity of a mold, the cavity defining a mold shape; b. moistening the rolled bone fiber article to induce expansion of the rolled bone fiber article within the cavity; and18105656448 1090129-795625 c. maintaining the rolled bone fiber article in the cavity for a time and one or more conditions sufficient for the rolled bone fiber article to conform to the mold shape and to maintain the mold shape when removed from the cavity of the mold.

6. The method of claim 5, wherein the mold shape is a substantially rectangular and defines a thickness, the method further comprising removing the rolled bone fiber article from the mold, wherein when removed the rolled bone fiber article has the form of a strip having about the thickness of the mold.

7. The method of claim 6, wherein the strip comprises a thickness of approximately 8 mm, a width of approximately 8 mm, and a length of approximately 15 cm.

8. The method of claim 6, wherein the strip comprises a thickness of approximately 5 mm, a width of approximately 12 mm, and a length of approximately 15 cm.

9. The method of claim 1 , wherein the rolling of the plurality of demineralized bone fibers is sufficient to cause the demineralized bone fibers to entangle and thereby form the rolled bone fiber article in absence of a wrapping sheath.

10. The method of claim 1 , wherein the rolled bone fiber article has a form of a cylinder having a diameter that is controllable based on a rolling technique used by the fiber rolling device.11 . The method of claim 10, wherein the diameter of the rolled bone fiber article is 1-50 mm.19105656448 1090129-79562512. A bone graft material comprising demineralized bone fibers, formed by the method of any preceding claim.

13. Use of a fiber rolling device to prepare a plurality of demineralized bone fibers for formation as a bone graft, the use comprising: a. preparing or having prepared a plurality of demineralized bone fibers by arranging the demineralized bone fibers in a substantially parallel orientation along a longitudinal axis, wherein the arrangement of demineralized bone fibers defines a length; and b. positioning the length of fibers in a fiber rolling device operable to roll the fibers into a rolled bone fiber article, thereby entangling the bone fibers and preparing the rolled bone fiber article for molding in a form of a molded bone graft.

14. The use of claim 13, further comprising moistening the rolled bone fiber article prior to molding.

15. The use of claim 13, further comprising disposing the rolled bone fiber article in a mold defining a cavity having a cavity shape.

16. The use of claim 15, further comprising maintaining the rolled bone fiber article in the mold for a time and under one or more conditions sufficient for the rolled bone fiber article to conform to the cavity shape of the cavity of the mold, wherein the rolled bone fiber article forms a bone graft having increased flexural strength compared to a bone fiber article composed of unrolled demineralized bone fibers.

17. The use of claim 13, wherein the rolled bone fiber article comprises an implantable bone graft having increased flexural strength compared to a bone fiber article composed of unrolled demineralized bone fibers.20105656448 1090129-79562518. The use of claim 13, wherein the rolled bone fiber article can be cut into various lengths such that multiple grafts can be produced simultaneously.

19. The use of claim 13, wherein the rolled bone fiber article is rolled within a cover and maintained as a cylindrical article with a diameter of 1 -50 mm and a length of 1-1000 mm.

20. A bone graft comprising a plurality of entangled demineralized bone fibers in a bundle defining a long axis, optionally further comprising at least one demineralized bone fiber wrapped around an exterior of the bundle along the long axis thereof.21 . The bone graft of claim 20, in a form of one of a strip, a rod, or a cylinder.

22. Use of the bone graft of any one of claims 12 or 21 , to repair a bone defect or bone injury in a subject in need thereof.

23. The use of claim 22, comprising implanting the bone graft at a bone defect site or bone injury site of the subject.

24. A method of repairing a bone defect or bone injury in a subject in need thereof, the method comprising implanting a bone graft comprising a plurality of entangled demineralized bone fibers.

25. The method of claim 24, wherein the entangled demineralized bone fibers demonstrate greater breakage resistance than non-entangled fibers.

26. The method of claim 24, wherein the entangled demineralized bone fibers are rolled to increase a flexural strength of the bone graft compared to a bone graft composed of unrolled demineralized bone fibers.21105656448 1

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