Reduction trauma screws and related methods

Abstract

Provided herein are reduction trauma screws comprising a headless insert into a substrate that couples to a reduction cap via a chosen lock structure (e.g., narrow threads, finger-trap locking, or a spiral bayonet mechanism). The cap or screw can include scaffolds with triply periodic minimal surfaces or folded-sheet architectures to promote bone in-growth. Additionally, a trephine channel may harvest autograft during insertion. Methods of implantation include aligning a drill guide, forming a borehole, and advancing a headless screw with a driver. The reduction cap is then engaged through a counter-torque approach, thereby achieving bone compression without further rotating the screw. The designs enable improved stability, straightforward revision, and adaptability for patient-specific anatomy.

Description

REDUCTION TRAUMA SCREWS AND RELATED METHODSTECHNICAL FIELD

[0001] This disclosure relates to a reduction trauma screw and related methods for bone implantation, for example, with plates, for reduction, traction, and fixation.BACKGROUND

[0002] When a bone fractures, the fragments can lose alignment and require reduction — restoring the bone’s natural position — through procedures that may be done either openly (with surgical exposure) or closed (without exposing the bone fragments). Orthopedic methods often employ plates and screws for fixation, enabling stable alignment. Despite refinements in surgical techniques and hardware, challenges persist in achieving a secure, anatomically correct reduction and stable long-term fixation.

[0003] In particular, bacterial colonization, infection, stiffness, nonunion, deformities, and other complications can arise from implanted hardware. Even after clinical success, bone mineral density tends to decrease in the presence of implanted devices, potentially leading to implant backout, loosening, or rod failure before adequate healing occurs. Although some devices emphasize fusion in an interbody cage, adapting a scaffold to support bone mineral density specifically within and around the vertebra or other fracture site remains a significant challenge.

[0004] Moreover, certain implants have not fully addressed the common reasons for revision surgery, which include screw loosening and hardware breakage. Because bone structure differs considerably depending on its location (vertebral, long bones, cortical vs. cancellous regions), there is a need for implants that better accommodate these biological variations. Approaches that incorporate both innovative locking engagements and scaffold designs capable of supporting ingrowth may yield improved clinical outcomes.SUMMARY

[0005] The present disclosure provides a reduction trauma screw with a headless design and a specialized coupling mechanism for attaching a reduction cap after initial placement. This two- stage assembly is configured to promote reliable bone compression, encourage osteointegration through advanced scaffold features, and collect autograft material to support healing. Byaddressing bone-density concerns and facilitating stable reductions, the disclosed technology potentially reduces the risk of revision surgeries for hardware failures.

[0006] The present disclosure provides a reduction trauma screw that comprises: a headless screw having at least one coupling structure at a proximal end; and a reduction cap adapted to couple to the headless screw via the at least one coupling structure after the headless screw has been inserted into a substrate, wherein the at least one coupling structure is configured to provide a locking engagement.

[0007] The present disclosure further provides a method of implanting a reduction trauma screw, comprising: inserting a headless screw having at least one coupling structure at a proximal end into a borehole in a bone using a headless driver; and coupling a reduction cap to the inserted headless screw via a reduction driver loaded with the reduction cap, by using the headless driver to counter-torque against the reduction driver to engage the at least one coupling structure.

[0008] Additional embodiments and features are set forth in part in the following description. They will become apparent to those skilled in the art upon examination of the specification or may be learned by the practice of the embodiments discussed herein. A further understanding of the nature and advantages of certain embodiments may be realized by reference to the remaining portions of the specification and the drawings, which form a part of this disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 shows a reduction trauma screw as described herein, including coupling structures.

[0010] FIG. 2 shows a detailed view of an angled reduction cap having a diamond lattice surface.

[0011] FIG. 3 shows a detailed view of a straight reduction cap having a diamond lattice surface.

[0012] FIG. 4 shows a frontal view of the reduction cap.

[0013] FIG. 5 shows a reduction cap, highlighting right and left specificity and variable compression levels.

[0014] FIG. 6 shows another view of reduction caps which provide multiple compression options.

[0015] FIG. 7 shows the finger-trap locking mechanism, depicting the radial flex of lattice fingers upon engagement with a matching protrusion and the secure snap-back action.

[0016] FIG. 8 shows a side view of the screw shank, illustrating the scaffold structure along its length, the orientation of normal threads, and the stepped proximal threads.

[0017] FIG. 9 shows a device comprising the reduction cap of FIG. 5 and the headless screw of FIG. 8.

[0018] FIG. 10 shows a nut for use in the screw assembly, featuring a rough topography and threading for effective countersinking.

[0019] FIG. 11 depicts the full screw assembly with the nut, highlighting the threaded section and rough topography on the shank.

[0020] FIG. 12 shows a shank and nut, illustrating a pin traversing both components.

[0021] Table 1 shows the reference numerals used in the figures.Table 1 - Reference numerals

[0022] The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements. The drawings provide exemplary embodiments or aspects of the disclosure and do not limit the scope of the disclosure.DETAILED DESCRIPTION

[0023] The present disclosure provides a reduction trauma screw. This screw comprises a headless screw with narrow threads at the proximal end and a reduction cap. The cap is adapted to couple to the headless screw via the narrow threads after the headless screw has been inserted into a substrate.

[0024] As used herein, “reduction cap” refers to a specialized component adapted to engage a headless screw and provide compression or fixation once the screw is inserted into a substrate. In certain embodiments, reduction caps are designed to attach through locking engagements such as bayonet mechanisms or finger-trap elements, facilitating stable bone alignment. Suitable examples include, but are not limited to, caps with scaffolds that permit tissue in-growth or caps configured for quick removal during explantation.

[0025] In certain embodiments, a reduction trauma screw comprises a headless screw having at least one coupling structure at a proximal end and a reduction cap adapted to couple to the headless screw via the at least one coupling structure after the headless screw has been inserted into a substrate, wherein the at least one coupling structure is configured to provide a locking engagement.

[0026] As used herein, “locking engagement” refers to a secure interaction between two or more components that reduces or prevents unintended relative movement. In certain embodiments, locking engagements are formed through mechanical features such as threads, latches, or radial expansions that hold a screw and a cap in place. Suitable examples include, but are not limited to, tight interference fits relying on finger-trap locking mechanisms or spiral bayonet interfaces.

[0027] In certain embodiments, the screw comprises the at least one coupling structure chosen from narrow threads, a finger-trap locking mechanism, or a spiral bayonet mechanism.

[0028] As used herein, “finger-trap locking mechanism” refers to a design in which flexible prongs or lattice fingers radially flex or collapse to grip a mating component and lock it in place. In certain embodiments, finger-trap locking mechanisms are made from spring-like metallic or polymeric materials to provide resilient engagement when a screw or other element is inserted.Suitable examples include, but are not limited to, slender lattice sleeves that snap onto a proximally located feature of a headless screw.

[0029] As used herein, “lattice finger” refers to a slender, flexible projection or portion of a structure that extends from a lattice-like framework. In certain embodiments, lattice fingers are dimensioned to bend or compress when engaging a mating component, providing a secure fit. Suitable examples include, but are not limited to, multiple thin prongs arranged around a screw's proximal region in a 3D-printed titanium device.

[0030] In certain embodiments, the screw comprises the finger-trap locking mechanism, wherein each finger has a thickness between about 100 and 300 microns to provide sufficient resiliency in a metallic 3D-printed structure.

[0031] As used herein, “bayonet mechanism” refers to an engagement system in which a component is inserted and then rotated to lock in place, often via aligned grooves or protrusions. In certain embodiments, bayonet mechanisms are used for medical devices to provide a twistlock connection between a cap and a headless screw. Suitable examples include, but are not limited to, single-start or multiple-start spiral bayonet catches that distribute shear forces around a circular interface.

[0032] In certain embodiments, the screw comprises the spiral bayonet mechanism, wherein the spiral bayonet mechanism comprises a helical groove on the proximal region of the headless screw and a matching protrusion formed on an interior surface of the reduction cap.

[0033] In certain embodiments, the screw comprises four or more starts in the spiral bayonet mechanism, each located at a different circumferential position.

[0034] In certain embodiments, the screw further comprises at least one scaffold on the reduction cap, the scaffold being configured to promote bony in-growth.

[0035] In certain embodiments, the scaffold on the reduction cap comprises a triply periodic minimal surface having a repeating pattern.

[0036] In certain embodiments, the scaffold on the reduction cap is a pseudorandom folded-sheet structure comprising a continuous sheet of topological genus-n.

[0037] In certain embodiments, the reduction cap comprises one or more windows, fenestrations, or ports in fluid communication with the scaffold.

[0038] As used herein, “fenestration” or “window” refers to an opening or aperture formed in a medical device or implant. In certain embodiments, fenestrations are provided to enable fluidexchange, tissue in-growth, or controlled access to internal components. Suitable examples include, but are not limited to, small circular holes in a reduction cap or multiple ports around a cannulated screw.

[0039] In certain embodiments, at least one of the headless screw or the reduction cap comprises a 3D-printed titanium alloy.

[0040] In certain embodiments, the headless screw further comprises a trephine channel configured to harvest autograft material during insertion into the substrate.

[0041] In certain embodiments, the at least one coupling structure is adapted so that the headless screw and the reduction cap can be removed together as a single unit for explantation.

[0042] As used herein, “explantation” refers to the removal of an implanted medical device or biological material from a patient's body. In certain embodiments, explantations are carried out after a healing period or when a device no longer meets the patient's clinical needs. Suitable examples include, but are not limited to, removing orthopedic screws once a fracture is stabilized and recovering vascular grafts for inspection or replacement.

[0043] FIG. 1 shows device 100 configured as a reduction trauma screw assembly, including headless screw 200 with optional threads 230, such as partially-threaded sections 234 and fully- threaded sections 236. Scaffold 280 is disposed along shaft 295. Various coupling structures 600 are depicted, including narrow thread 630, spiral bayonet mechanism 610, and finger-trap locking mechanisms 620 are depicted. Proximal end 210 is configured with a drive 215, and a cannulation 260 runs from the proximal end 210 to the distal end 220 of the headless screw 200.

[0044] FIG. 2 shows a detailed view of an angled reduction cap 500 having a diamond lattice 285 on the exterior surface between the cap top 510 and cap bottom 520.

[0045] FIG. 3 shows a detailed view of a straight reduction cap 500 having a diamond lattice 285 surface on the exterior surface between the cap top 510 and cap bottom 520.

[0046] FIG. 4 shows a frontal view of the cap top 510 of a reduction cap 500 having flanges 560 disposed around the periphery of the cap.

[0047] FIG. 5 shows a reduction cap 500 having a diamond lattice 285 and an external cap thread 535, highlighting right and left specificity and variable compression levels.

[0048] FIG. 6 shows another view of a reduction cap 500, having an angled cap top 510, a diamond lattice 285, and an external cap thread 535, thus providing multiple compression options.

[0049] FIG. 7 shows the finger-trap locking mechanism 620. Lattice fingers 622 engage with matching protrusions 626 when a push force 625 is applied. The push force 625 causes the lattice finger to flex 622a as it slides past the matching protrusions 626. Once the lattice finger relaxes 622b, it snaps back into place, forming a locking engagement 700 with the matching protrusion 626. These lattice fingers 622 can be disposed in radial rows 624 around the shaft 295 of the headless screw 200. Variables to consider in these embodiments are the lattice length, lattice thickness, the number of fingers per row, the radial row diameter, and the radial row spacing.

[0050] FIG. 8 shows a side view of a headless screw 200, illustrating the scaffold 280 along its length, the orientation of normal threads 230 at the distal end 220, and the stepped threads 212 at the proximal end 210.

[0051] FIG. 9 shows a device 100 comprising the reduction cap 500 of FIG. 5 and the headless screw of FIG. 8, detailing the integration of a diamond lattice 285, rough topography 270, cannulation 260, and fenestration 250.

[0052] FIG. 10 shows a nut 650 for use with a headless screw 200, featuring a rough topography 270 and threading 635 for effective countersinking.

[0053] FIG. 11 shows the full screw assembly 100 with the nut 650 and a headless screw 200, highlighting the threaded section 230 at the distal end 220 and rough topography 270 on the headless screw 200. Nut 650 is disposed on the proximal end 210 of the headless screw 200.

[0054] FIG. 12 shows a headless screw 200 and nut 650, illustrating a pin 660 traversing both components.Scaffold

[0055] In certain embodiments, the scaffold comprises a folded sheet scaffold. As used herein, “folded sheet scaffold” refers to a shellular porous structure with a pseudorandom orientable architecture derived from a continuous folded sheet of a topological genus-n. This architecture divides the three-dimensional space into two distinct, non-intersecting sub-volumes, or labyrinths, which, in certain embodiments, are incongruent. The pseudorandom orientation of this structure is influenced by a dimensionless three-dimensional noise field, the characteristics of which — including type, frequency, jitter, and magnitude — are adjustable. In certain embodiments, the folded sheet scaffold exhibits a continuous, perforated, or functionally graded sheet architecture. In various embodiments, the architecture is semi-regular or determined by specific modulating algorithms that control spatially-varying features.

[0056] “Dimensionless” refers to a characteristic, quantity, or property that does not have an associated physical or spatial dimension. It is a measure that is purely numerical and independent of any unit of measurement. In the case of a “dimensionless 3 -dimensional noise field,” the term “dimensionless” refers to the noise field being defined or characterized by numerical values that do not correspond to a specific physical dimension but rather serve to influence the properties or characteristics of the folded sheet scaffold.

[0057] “Functionally graded” refers to a characteristic of the sheet architecture where its properties vary gradually over volume due to a continuous change in structure or composition. This grading can be designed to meet specific requirements of different parts of the scaffold.

[0058] The term “genus-n” is a topological concept referring to the number of “holes” or “handles” in a given surface. In the context of a “continuous folded sheet of topological genus- n,” it denotes the complexity of the folded sheet's structure, with n indicating the number of such features.

[0059] “Labyrinth” refers to the complex network-like structure formed within the divided subvolumes of the three-dimensional space. These labyrinths result from the pseudorandom orientation of the folded sheet scaffold, creating intricate pathways or channels.

[0060] “Perforated” refers to the presence of a series of holes or openings in the sheet architecture of the scaffold. These perforations range in size and arrangement. They contribute to the porous nature of the scaffold, influencing its functional properties.

[0061] “ Semi-regular” refers to a characteristic of the sheet architecture where there is a degree of regularity or consistency in the structure but not absolute uniformity. In certain embodiments, “semi-regular” refers to patterns or features that repeat with some variation.

[0062] “ Shellular” refers to a specific type of porous structure that resembles a shell or a series of shells. This structure is characteristic of the folded sheet scaffold, contributing to its overall architecture and functional properties.

[0063] “Spatially-varying feature” refers to characteristics or properties of the folded sheet scaffold that change or vary across different points or regions in space. These features include, but are not limited to, variations in the structure, composition, or functional properties of the scaffold.

[0064] “ Statistical variation” in the context of a “dimensionless 3-dimensional noise field” refers to the fluctuations or changes in the noise field that follow a certain statistical distribution. This variation influences the pseudorandom orientation of the folded sheet scaffold.

[0065] “ Sub-volume” refers to separate or distinct portions of a three-dimensional space that do not share common points or intersect. These sub-volumes are created by dividing the three- dimensional space by the continuous folded sheet of topological genus-n.

[0066] In certain embodiments, bone screws were 3D-printed and tested with the diamond lattice structure. In certain embodiments, scoop features are located along a helical pattern, for example, corresponding to the helical pattern of the openings into the internal lattice structure.

[0067] The design was based on a triply periodic minimal surface (TPMS), a minimal surface in R3that is invariant under a rank-3 lattice of translations. These surfaces have the symmetries of a crystallographic group. Numerous examples of cubic, tetragonal, rhombohedral, and orthorhombic symmetries are known.

[0068] Specifically, a Schwartz Diamond TPMS was used for the lattice, formed from symmetry arguments, remapped from Cartesian coordinates to spherical polar coordinates about the central axis of the screw shaft, sheared to form a helical wrap, thickened, subtracted, and as intersected with the 3D geometry space for the scaffold.

[0069] The surfaces were generated using symmetry arguments: Given a solution to Plateau's problem for a polygon, reflections of the surface across the boundary lines also produce valid minimal surfaces that can be continuously joined to the original solution. If a minimal surface meets a plane at right angles, then the mirror image in the plane can also be joined to the surface. Hence, periodic surfaces can be constructed given a suitable initial polygon inscribed in a unit cell.

[0070] The equation 1 approximates the TPMS for these bone screws: cos(x) cos(j) cos(z) - sin(.r) sin(y) sin(z) = 0 (1) which is the specific base equation for this embodiment of the bone screw. The x, y, and z variables define the periodicity (i.e., pattern) in X / Y / Z, similar to how cubic lattices are defined. This surface is called a “diamond” because it has two intertwined congruent labyrinths, each having the shape of an inflated tubular version of the diamond bond structure. For the sake of discussion, a regularly repeating cell has been assumed, although TPMS geometry is influencedtopologically to be pseudo-random. An exact expression exists regarding elliptic integrals based on the Weierstrass-Ennepar parameterization.

[0071] As an equation, it defines the Schwarz D surface through infinite real space. Such a surface splits real space into two identical volumes — Positive space passes into negative space defines the iso- or mid-surface. A 2-dimensional slice through the Schwarz Diamond mathematical field shows “positive” and “negative” space. In certain embodiments, the cubic repeating pattern is 1.8 mm in SJ !Z.

[0072] After creating the Schwarz equation, it was remapped helically (i.e., twisted) to create the base of the final shape. To do this, the equation was mapped from Cartesian space to polar space using conventional methods. The periodicity was mapped cylindrically. That is, the number of “spokes” radially remained a multiple of the selected cell size. The remap was about the central axis of the screw shaft.

[0073] After remapping, the space was sheared to create the helical wrap, similar to how an inclined plane is wrapped around a cylinder to create a screw. To create the shear, the Schwarz D equation is remapped from X / Y / Z coordinate space by shearing one (or multiple of the coordinates): x -> x, y - y, and z -> z + x, where the Schwarz Diamond was sheared in the XZ plane. Such a shear operation maintained a continuous field.

[0074] After the field was sheared and remapped cylindrically, it was thickened using an absolute value operation, which converted the negative space of the equation into a positive in three dimensions. The helical wrap of the medical device is defined as a period three times the size of the cubic repeating pattern (5.4 mm), forming a single helix with a circumferential count of three for three radial spokes. After this, a subtract mathematical operation offsets the central geometry to create a sheet-like structure. In certain embodiments, the walls are about 0.50 mm thick. Once the thin-walled lattice field was intersected with the 3D geometry space that defines where the lattice exists, to model for the scaffold was produced.Screw

[0075] Screws are the basic elements for achieving interfragmentary compression. They can be used as lag screws, either individually or through plates, to bring two fragments together under compression. Screw are also used to fix plates to the bone. Screw sizes are named according to the outside diameter of their threaded portion. Cortex screws are sized for hard cortical bone, such as in the diaphysis of long bones. Typically, cortex screws are not self-cutting, and thethread has to be cut before insertion. Cancellous bone screws are applied to metaphyseal and epiphyseal regions, where the bone is softer and spongy and the cortex thin.

[0076] As used herein, “polyaxial” refers to a characteristic or property of an object or system that allows for rotation or movement along multiple axes. In certain embodiments, a polyaxial system or component can be oriented or adjusted in various directions without being confined to a single plane of rotation. For instance, a polyaxial screw in a surgical application may be adjusted to align with different anatomical structures, or a polyaxial joint in a mechanical system may allow for multi -directional movement.

[0077] In certain embodiments, the screw is cannulated. In certain embodiments, the screw is non-cannulated. When a fracture in the metaphysis or the epiphysis has been reduced and temporarily fixed with a Kirschner wire, a cannulated screw can be implanted into the site using the Kirschner wire as a guide wire.

[0078] As used herein, “borehole” refers to a passage created in a bone or other substrate for receiving or guiding a medical device. In certain embodiments, boreholes are formed using drilling or reaming procedures to accommodate headless screws or other implants. Suitable examples include, but are not limited to, a cylindrical hole in the femur for intramedullary nails and a smaller aperture in vertebral bone for screw insertion.The length and diameter of the screw are chosen for the needed application. In certain embodiments, the length is between 8 mm and 200 mm, such as between 34 mm and 60 mm, for example, 34 mm, 36 mm, 38 mm, 40 mm, 42 mm, 44 mm, 46 mm, 48 mm, 50 mm, 52 mm, 54 mm, 56 mm, 58 mm, or 60 mm. In certain embodiments, the length is greater than 8 mm. In certain embodiments, the length is less than 200 mm.

[0079] The diameter of the screw can be defined about the thread diameter, the drill bit diameter for a gliding hole or a threaded hole, or the tap diameter. In certain embodiments, the diameter is between 4 mm and 6.5 mm, such as 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, and 6.5 mm. In certain embodiments, the thread diameter is between 1.0 mm and 7.3 mm, such as 1.0 mm, 1.3 mm, 1.5 mm, 2.0 mm, 2.4 mm, 2.7 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 6.5 mm, 7.0 mm, 7.1 mm, and 7.3 mm. In certain embodiments, the diameter is greater than 1 mm. In certain embodiments, the diameter is less than 7.3 mm.

[0080] In certain embodiments, the screw is self-tapping. In certain embodiments, the screw is non-self-tapping. In certain embodiments, the screw is self-drilling.

[0081] The design of the screw thread affects the screw’s holding power. Because the strength of the bone is about ten times less than that of the metal of the screw, in certain embodiments, the threads have an asymmetrical buttress profile. For the screw to hold, the threads should engage the entire far cortex of the bone. The tip of the screw and one or two threads should protrude on the opposite of the bone.

[0082] In certain embodiments, the thread length of the screw is short. In certain embodiments, the thread length is long. In certain embodiments, the thread length is partial. In certain embodiments, the thread length is full. In certain embodiments, the thread length is a specified length, such as 16 mm or 32 mm.

[0083] The drive type for the screw and the cap can be different shapes and sizes, depending on the size of the screw and its application. In certain embodiments, the drive type is cruciform, hexagonal, star, or lobular (Torx). A common example of a cruciform drive type is the Phillips head screw. “Torx” is a trademark for a type of screw drive characterized by a 6-point starshaped pattern, The official generic name for Torx, standardized by the International Organization for Standardization as ISO 10664, is hexalobular internal.

[0084] When a star or lobular drive type, different numbers of points may be used, such as 5- pointed, 6-pointed, 7-pointed, 8-pointed, 10-pointed, or 12-pointed stars or lobular screw drives. Torx head sizes are described using the capital letter “T” followed by a number ranging from T1 to T100. A smaller number corresponds to a smaller point-to-point dimension of the screw head (the diameter of the circle circumscribed on the cross-section of the tip of the screwdriver). The “external” variants of Torx head sizes are described using the capital letter “E” followed by a number ranging from E4 to E44. See Table 2 for details.Table 2 - Properties of various Torx drives

[0085] In certain embodiments, the drive type is chosen from 1.0 mm cruciform, 1.3 mm cruciform, 1.5 mm cruciform, 2.0 mm cruciform, 2.4 mm cruciform, 3.0 mm cruciform, 2.5 mm hexagonal, 3.5 mm hexagonal, 4.0 mm hexagonal, T8, T15, and T25.

[0086] Built-in channels for autograft collection enhance the structural integrity of the implantation. This superiorly resisted bone mineral density loss and reduced micromotion. The randomized porosity pattern of scaffold was typical of native trabecular bone. In addition, built- in struts provided structural integrity.

[0087] As used herein, “autograft” refers to a tissue graft harvested from a patient's own body that is implanted at another site within that same patient. In certain embodiments, autografts are harvested from bone, muscle, or other tissues. Suitable examples include, but are not limited to, cancellous bone from the iliac crest and cortical bone from long bones.

[0088] In certain embodiments, the screw and cap are manufactured in cobalt chrome, titanium, and magnesium-infused titanium. In certain embodiments, the screw and cap comprise Ti-6A1- 7Nb, Ti6A14V-ELI (Grade 5 Titanium Alloy) per ASTM F136, 316L stainless steel per ASTM F138, 316LVM stainless steel per ASTM F138, Mg-PSZ per ASTM F2393-12, or Mg-Ti with 5- 35 wt.% Mg. 316L stainless teat typically contains 62.5% iron, 17.6% chromium, 14.5% nickel, 2.8% molybdenum and minor alloy additions. A low carbon content is specified to ensure that the material is free from susceptibility to intergranular corrosion. Titanium alloys have improved biocompatibility, functional performance, excellent corrosion resistance, and no allergic reactions. Other materials fabricating the screw included pre-packed demineralized bone matrix (DBM), pre-packed synthetic DBM, and unpacked DBM.

[0089] In certain embodiments, the internal core of the screw is a trephine to collect and harvest autograft upon and / or during insertion of the screw.

[0090] In certain embodiments, post-implantation options prevent revision surgery through polymer injection through the screw.

[0091] In certain embodiments, the screw does not exhibit screw loosening, screw backout, rod breakage, or lowered bone mineral density.

[0092] In certain embodiments, the screw comprises a shaft that is thicker than the core, thereby strengthening the point where rod breakage most frequently occurs during screw installation.

[0093] In certain embodiments, the screw has reduced one or more screw loosening, screw backout, rod breakage, and lowered bone mineral density.

[0094] The disclosed screws focus on bone growth throughout the core to minimize shear stresses on the distal tip and spread micromotion evenly throughout the screw to encourage bony ingrowth.

[0095] In certain embodiments, the scaffold of the screw provides options for simple to complex bone mineral densities and immunocompromised patients. In certain embodiments, the scaffold is impregnated with one or more biologies, antibiotics, demineralized bone matrices, nanotechnology, or regenerative medicine therapies.

[0096] In certain embodiments, the screw is configured to help bone in-growth through the screw by using the scaffold, similar to native trabecular bone. In combination with the thread and the scaffold, the core aids autograft harvesting during the insertion process to push autograft into built-in channels within the core of the screw. The walls surrounding the pores harvest the autograft and act as trephines. This structure also aided the screw’s structural integrity, resisted bone mineral density loss, and reduced micromotion.

[0097] The screws disclosed herein overcome the many failures of the prior art screws. In certain embodiments, the screw lacks a windshield wiper effect. In certain embodiments, the screw resists back out. In certain embodiments, the screw does not exhibit excessive micromotion. In certain embodiments, the screw has a low frequency of low- virulent microorganisms detected by sonication, for example, due to individual screw sterilization and packaging. In certain embodiments, the head and shaft of the screw resist failure. In certain embodiments, the screw is adapted for each type of bone quality. In certain embodiments, the screw has adequate thread depth. In certain embodiments, the screw withstands insertion torque, particularly at the head-to- screw coupling. In certain embodiments, the fatigue lifespan of the screw does not decrease when the screw is fully inserted. In certain embodiments, the screw has good instrumentation. In certain embodiments, the screw achieves angulation for rod acceptance. In certain embodiments, the screw does not have cyclic loading based on physiological conditions during walking. In certain embodiments, the screw does not fail in long-segment posterior cervical fusion, not requiring concomitant C6 or T1 buttress pedicles. In certain embodiments, the screw distributes stress. In certain embodiments, the screw does not immunocompromise the patient. In certain embodiments, the screw does not comprise PEEK. In certain embodiments, the screw does not have tulip or locking cap stresses.

[0098] In some embodiments, the distal tip of the screw has a surface configuration chosen from angled, irregular, uniform, non-uniform, offset, staggered, tapered, arcuate, undulating, mesh, porous, semi-porous, dimpled, pointed, textured, or combinations thereof. In some embodiments, the distal tip includes a nail configuration, barbs, expanding elements, raised elements, ribs,and / or spikes to provide a fabrication platform for forming a portion thereon via additive manufacturing. In some embodiments, the distal tip has a cross-section configuration chosen from oval, oblong triangular, square, polygonal, irregular, uniform, non-uniform, offset, staggered, tapered, or combinations thereof.

[0099] In some embodiments, the leading surface and / or the trailing surface comprises at least one tissue-gathering member. In some embodiments, the tissue gathering member comprises a cutting edge. In some embodiments, the cutting edge is configured to be rasp-like. In some embodiments, the cutting edge is configured to engage tissue, for example, to cut, shave, shear, incise, or disrupt the tissue. In some embodiments, the cutting edge is configured to be cylindrical, round, oval, oblong, triangular, polygonal, having planar or arcuate side portions, irregular, uniform, non-uniform, consistent, variable, horseshoe shape, U-shape, or kidney bean shape. In some embodiments, the cutting edge is rough, textured, porous, semi-porous, dimpled, knurled, toothed, grooved, or polished to engage and cut the tissue. In some embodiments, the cutting edge forms a tunnel configured to guide, drive, or direct the cut tissue into the void, such as fusing the screw with the tissue.

[0100] In certain embodiments, the screw is a 3D-printed porous screw. Its porosity mimics native bone to attach and keep stem cells, growth factors, and other proteins within the structure of the screw and encourage bone growth through the screw, stabilizing the overall construct. During insertion into bone, the built-in trephines collect autograft and regenerative cells within the porous matrix. The disclosed topography attracts bone-forming stem cells within and around the device, reducing overall construct macromotion. In certain embodiments, this device enables surgeons to meet patient-specific needs, such as, but not limited to, spray ing / injecting regenerative products to stimulate the bone-forming osteogenic cascade, proactively injecting the screw scaffold with antibiotics for diabetic-prone infections, and the option to inject bone cement to further stabilize the construct in severely osteoporotic bone.

[0101] In certain embodiments, the screw reduces revision rates, improves bone mineral density, and / or addresses patient-specific needs during spine fusions. In certain embodiments, bone mineral density improves, constructs are stabilized, and the likelihood of revision is reduced.

[0102] In certain embodiments, a screw is a 3D-printed titanium porous screw having a pattern resembling native bone, configured to attach to surrounding bone, retain osteogenic stem cells, and collect autograft material within its porous structure. In certain embodiments, the porouspattern also permits the injection of polymers or regenerative therapies through the screw, reducing the likelihood of failure. In certain embodiments, stem cell therapies are injected through the screw implant, providing further support for bone healing.

[0103] In certain embodiments, the surgeon can inject or spray the screw with autologous concentrated stem cells. Without wishing to be bound by theory, as the screw turns during insertion into the bone, the screw’s pores collect an autograft / stem cell mixture internally using its built-in trephines. The osteogenic stem cells then bind with the concentrated blood stem cells and signal the process of mutation and replication, forming more osteogenic cells within the screw, followed by a healing cascade of bone directed within and around the screw. In these embodiments, the combination of (a) osteoconductive (bone grows on the surface), (b) osteoinductive (recruiter of cells for bone healing), and (c) osteogenic (development and formation of bone) healing cascade of the stem cells improve bone mineral density and support superior bone integration and pullout strength.

[0104] In certain embodiments, the patient is diabetic and prone to infection. In these embodiments, the surgeon can inject a mixture comprising a calcium sulfate product and antibiotics through the screw before or after insertion or on the screw within the pedicle to provide antibiotic delivery in the area. In certain embodiments, the antibiotics are delivered for between two and six weeks. As such, the likelihood of revision due to infection is reduced.

[0105] The present disclosure provides a device formed from a scaffold disclosed herein. In certain embodiments, the device is cannulated and fenestrated with the scaffold. In certain embodiments, the device comprises a threaded distal region, an optionally threaded central region, and an optionally threaded proximal region, depending on the compressive forces.

[0106] In some embodiments, the screw is configured with features that facilitate bone to grow through the structure of the screw from opposing sides allowing the bone to connect through the screw. In some embodiments, the structure is narrow, such as through the screw thread, thereby permitting rapid through growth. In some embodiments, the structure is deeper, such as through the minor diameter, thus bonding stronger. In some embodiments, the feature is a void in the screw or porous or structured to promote bone growth. In some embodiments, the structure collects autografts within the channels inside the device. In some embodiments, the feature is impregnated with one or more polymers.

[0107] In some embodiments, the device is configured to enhance the stabilization and fixation of bone screws within the bone and improve bone mineral density. In some embodiments, the device includes a spinal implant configured for engagement with cortical bone and cancellous bone. In some embodiments, the device is configured to resist and / or prevent toggling on a bone screw when the bone screw is engaged with dense cortical bone and a less dense cancellous bone resulting from a load on the bone screw. In some embodiments, the device is configured to resist and / or prevent the loosening of the bone screw from the cortical bone and, in some instances, pull it out from the bone. In some embodiments, the device is configured to facilitate bone through-growth to improve bone attachment to the bone screw. In some embodiments, the bone screw is anchored in the bone, thereby reducing pullout. In some embodiments, the bone screw is designed to spread micromotion and reduce shearing to strengthen bone mineral density.

[0108] In some embodiments, the device includes a bone screw having bone through-growth through the core of the screw to reduce toggle and potential failure of the screw. In some embodiments, the bone screw includes features that allow the bone to grow through the structure of the bone screw from opposing sides allowing bone to connect through those bone screw structures. In some embodiments, the bone screw includes features that may be narrow, such as through the bone screw thread, which would allow for rapid through-growth. In some embodiments, the bone screw includes features that may be deeper, such as through the minor diameter, which would provide a larger volume of bone through-growth. In some embodiments, the bone screw includes features that may be a void or cavity through opposite sides of the bone screw and / or a void or cavity that enters and exits from the same or adjoining surfaces. In some embodiments, the void or cavity may contain a scaffold for the bone to attach or a porous structure on the surface of the void.

[0109] In some embodiments, the bone screw includes features or structures that may be disposed along a core of the bone screw. In some embodiments, the bone screw includes features or structures that may be disposed continuously along a surface of the bone screw, such as, for example, along a distal end. In some embodiments, the bone screw includes features or structures that may be disposed discontinuously along a portion of the bone screw. In some embodiments, the bone screw includes features or structures that may include a scaffold or polymers.

[0110] In some embodiments, the device comprises a spinal implant having a hybrid configuration that combines a manufacturing method, such as, for example, one or more priormanufacturing features and materials, and a manufacturing method, such as, for example, one or more additive manufacturing features and materials. In some embodiments, additive manufacturing includes 3-D printing. In some embodiments, additive manufacturing includes fused deposition modeling, selective laser sintering, direct metal laser sintering, selective laser melting, electron beam melting, layered object manufacturing, and stereolithography. In some embodiments, additive manufacturing comprises one or more chosen from rapid prototyping, desktop, direct, digital, instant, and on-demand manufacturing. In some embodiments, the device comprises a spinal implant manufactured by a fully additive process and grown or otherwise printed.[OUl] In certain embodiments, the devices comprises one or more chosen from demineralized bone matrix (DBM), pre-packed DBM, pre-packed synthetic DBM, unpacked DBM, and magnesium-infused titanium.

[0112] In some embodiments, the device comprises a spinal implant, such as, for example, a bone screw manufactured by combining traditional manufacturing methods and additive manufacturing methods. In some embodiments, the bone screw is manufactured by applying additive manufacturing material, where the bone screw can benefit from the materials and properties of additive manufacturing. In some embodiments, traditional materials are used where the benefits, such as physical properties and cost, are superior to those resulting from additive manufacturing features and materials.

[0113] In some embodiments, the device treats a spinal disorder chosen from degenerative disc disease, disc herniation, osteoporosis, spondylolisthesis, stenosis, scoliosis, other curvature abnormalities, kyphosis, tumor, and fractures.

[0114] “Treating” or “treatment” of a disease or condition refers to performing a procedure that may include administering one or more drugs to a patient, employing implantable devices, and / or employing instruments that treat the disease, such as microdiscectomy instruments to remove portions bulging or herniated discs, and / or bone spurs, to alleviate signs or symptoms of the disease or condition. Treating or treatment does not require complete alleviation of signs or symptoms, does not require a cure, and specifically includes procedures that have a marginal effect on the patient. For example, treatment can include inhibiting the disease, e.g., arresting its development, or relieving the disease, e.g., causing regression.

[0115] “Prevention” refers to alleviation before signs or symptoms of a disease or condition appear. Thus, prevention includes preventing the disease from occurring in a patient who may be predisposed to the disease but has not yet been diagnosed as having it.

[0116] “ Tissue” includes soft tissue, ligaments, tendons, cartilage, and / or bone. In certain embodiments, the tissue is cancellous bone, cortical bone, or corticocancellous bone.

[0117] In some embodiments, devices are used with other osteal and bone-related applications, including diagnostics and therapeutics. In some embodiments, devices are alternatively employed in surgical treatment with a patient in a prone or supine position and / or employ various surgical approaches to the spine, including anterior, posterior, posterior mid-line, lateral, posterolateral, and / or anterolateral approaches, and in other body regions such as maxillofacial and extremities. The devices may also be alternatively employed with procedures for treating the lumbar, cervical, thoracic, sacral, and pelvic regions of a spinal column. The devices may also be used on animals, bone models, and other non-living substrates, for example, in training, testing, and demonstration.

[0118] In certain embodiments, the device is a custom medical device. In certain embodiments, the device is adapted for sports medicine.

[0119] In certain embodiments, the device is temperature-sensing. In certain embodiments, the device is pH-balancing.

[0120] In certain embodiments, the devices are fabricated having a porosity with a porogen that is spheroidal, cuboidal, rectangular, elongated, tubular, fibrous, disc-shaped, platelet-shaped, polygonal, or a mixture thereof. In some embodiments, the porosity is based on a plurality of macropores, micropores, nanopores structures, and / or a combination thereof.

[0121] In certain embodiments, the device is fabricated from biologically acceptable materials suitable for medical applications, including metals, synthetic polymers, ceramics, bone material, and composites thereof. In certain embodiments, the device comprises one or more chosen from a metal, ceramic, rubber, hydrogel, rigid polymer, fabric, bone material, and composites thereof.

[0122] In certain embodiments, the device comprises a metal chosen from stainless steel alloys, aluminum, commercially pure titanium, titanium alloys, Grade 5 titanium, superelastic titanium alloys, magnesium-infused titanium, cobalt-chrome alloys, superelastic metallic alloys such as nitinol, super elastoplastic metals such as Gum Metal®. In certain embodiments, the device comprises a ceramic and composites thereof, such as calcium phosphate (e.g., Skelite™). Incertain embodiments, the device comprises a rubber chosen from poly aryl etherketone (PAEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketone (PEK), carbon- PEEK composites, PEEK-BaSCh rubber, polyethylene terephthalate (PET), silicone, polyurethane, silicone-polyurethane copolymer, and polyolefin rubber. In certain embodiments, the device comprises a hydrogel. In certain embodiments, the device comprises fabric. In certain embodiments, the device comprises a rigid polymer chosen from polyphenylene, polyimide, polyetherimide, polyethylene, and epoxy. In certain embodiments, the device comprises bone material chosen from autograft, allograft, xenograft, or transgenic cortical and / or corticocancellous bone. In certain embodiments, the device comprises tissue growth or differentiation factors. In certain embodiments, the device comprises resorbable materials, such as composites of metals and calcium-based ceramics, composites of PEEK and calcium-based ceramics, composites of PEEK with resorbable polymers, totally resorbable materials, such as calcium-based ceramics, for example, calcium phosphate, tri-calcium phosphate (TCP), hydroxyapatite (HA)-TCP, calcium sulfate, or other resorbable polymers, such as polyketide, polyglycolide, polytyrosine carbonate, polycaprolactone, and other combinations.

[0123] In certain embodiments, the device comprises a rubber chosen from poly aryl etherketone (PAEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketone (PEK), carbon-PEEK composites, PEEK-BaSCh rubber, polyethylene terephthalate (PET), silicone, polyurethane, silicone-polyurethane copolymer, polyolefin rubber, synthetic collagen, and collagen matrix. In certain embodiments, the device comprises synthetic collagen. In certain embodiments, the device comprises a collagen matrix.

[0124] In certain embodiments, the device comprises magnesium, vitamins, and minerals. “Vitamin” refers to an organic molecule (or a set of molecules closely related chemically, i.e., vitamers) that is an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism. Some sources list fourteen vitamins, including choline, but major health organizations typically list thirteen: vitamin A (as all-Zra / zs-retinol, all-Zrans-retinyl- esters, as well as all- / ra / / .s-beta-carotene and other provitamin A carotenoids), vitamin Bi (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin Bs (pantothenic acid), vitamin Be (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B12 (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (phylloquinone and menaquinones). In the context of nutrition, a “mineral” refers to achemical element required as an essential nutrient by organisms to perform functions necessary for life, including potassium, chlorine, sodium, calcium, phosphorous, magnesium, iron, zinc, manganese, copper, iodine, chromium, molybdenum, selenium, and cobalt.

[0125] In certain embodiments, the device comprises a metal chosen from iron, stainless steel alloys, aluminum, commercially pure titanium, titanium alloys, Grade 5 titanium, superelastic titanium alloys, magnesium-infused titanium, cobalt-chrome alloys, superelastic metallic alloys such as nitinol, super elastoplastic metals such as Gum Metal®. In certain embodiments, the device comprises titanium. In certain embodiments, the device comprises iron.

[0126] In certain embodiments, the device is manufactured or 3D-printed from materials such as titanium, titanium alloy, cobalt chrome, carbon fiber, magnesium-infused titanium, iron, or stainless steel. In certain embodiments, the device is manufactured from a shape memory alloy or shape memory polymer, allowing the device to conform to an anatomical shape of the patient’s body.

[0127] In certain embodiments, the device comprises magnesium-infused titanium. In certain embodiments, the device comprises an angiotensin receptor blocker coating. In certain embodiments, the device comprises a type-1 cartilage collagen coating. In certain embodiments, the device is infused with an antibiotic.

[0128] In certain embodiments, the device is used with surgical methods or techniques, including, but not limited to, open surgery, mini-open surgery, minimally invasive surgery (MIS), and percutaneous surgical implantation, whereby the injured bone is accessed through a miniincision or a sleeve provides a protected passageway to the area. Once access to the surgical site is obtained, surgical treatment can treat a disease or disorder, such as a reduction, traction, or installing plates and screws.

[0129] In certain embodiments, the surface of the devices comprises a non-solid configuration, such as a lattice. In some embodiments, the non-solid configuration comprises a porous structure or a trabecular configuration.

[0130] In various embodiments, the non-solid configuration is configured to provide one or a plurality of pathways to aid bone growth within and through from one surface to an opposite surface of the device. In some embodiments, the lattice comprises one or more portions, layers, or substrates. In some embodiments, one or more portions, layers, or substrates of the lattice are disposed side by side, offset, staggered, stepped, tapered, end to end, spaced apart, in series, orparallel. In some embodiments, the lattice defines a thickness, which may be uniform, undulating, tapered, increasing, decreasing, variable, offset, stepped, arcuate, angled, and / or staggered. In some embodiments, one or more lattice layers are disposed in a side-by-side, parallel orientation within a wall. In certain embodiments, the lattice comprises one or more layers of a material matrix.

[0131] In some embodiments, the lattice comprises a plurality of nodes and openings disposed in rows and columns or randomly. In some embodiments, the plurality of nodes and openings are disposed in series. In some embodiments, the plurality of nodes and openings are disposed in parallel.

[0132] In some embodiments, the lattice forms a rasp-like configuration. In some embodiments, the lattice is configured to engage tissue. In certain embodiments, the engagement of the lattice is to cut, shave, shear, incise or disrupt the tissue. In some embodiments, the lattice comprises a configuration chosen from cylindrical, round, oval, oblong, triangular, polygonal having planar or arcuate side portions, irregular, uniform, non-uniform, consistent, variable, horseshoe shape, U-shape, or kidney bean shape. In some embodiments, the lattice is rough, textured, porous, semi-porous, dimpled, knurled, toothed, grooved, or polished, for example, to engage and cut the tissue. In some embodiments, the lattice forms a tunnel configured to guide, drive, or direct the cut tissue into an opening, such as fusing the device to the tissue.

[0133] In certain embodiments, the screw 200 is injected or sprayed with a material, such as BMA concentrate, calcium phosphate, biologic, and / or antibiotics. The filled or coated screw rested for 10-15 minutes before insertion for the material to absorb.

[0134] In certain embodiments, an aperture in the proximal portion of the screw is configured for a syringe to pull or push cells into the screw structure pre- or post-implantation. In certain embodiments, an adapter connects the syringe to the screw. In certain embodiments, the aperture may be in fluid communication with the porous scaffold of the screw and / or one or more lumina. In certain embodiments, the screw comprises one lumen in fluid communication with the aperture and extends the length of the screw toward the screw tip.Plates

[0135] In certain embodiments, screws and caps disclosed herein are used with one or more plates having a plurality of holes to receive the screws and / or caps for fixation of the plate to a bone. Plates may be applied in various modes, including protection (neutralization),compression, bridging, and buttress (antiglide). The plate may be larger or smaller, thicker, or thinner as appropriate to various anatomic sites and loads. The holes in the plate are designed, for example, to receive locking screws or nonlocking screws or to aid dynamic compression.

[0136] Open Reduction Internal Fixation (ORIF) involves the implementation of implants to guide the healing process of a bone, as well as the open reduction, or setting, of the bone. Open reduction refers to open surgery to set bones, as is necessary for some fractures. Internal fixation refers to the fixation of screws and / or plates, intramedullary rods, and other devices to enable or facilitate healing. Rigid fixation prevents micro-motion across lines of fracture to enable healing and prevent infection, which happens when implants such as plates (e.g., dynamic compression plate) are used. ORIF techniques are often used in cases involving severe fractures, such as comminuted or displaced fractures, or where the bone would not heal correctly with casting or splinting alone.

[0137] The plate fits the shape of the bone. For example, the midshaft of many long bones is straight, so plates applied to these regions are not contoured. However, many bones flare towards their metaphysis, so plates applied in these regions are contoured. A flexible template aids plate contouring. Some plates reduce contact areas on the bone. Reconstruction plates contour easily in complex anatomic locations.

[0138] Anatomic plates are pre-contoured to fit the region. These plates are for an average patient, so adjustments may be needed to fit individual patients. A protection plate neutralizes bending and rotational forces to protect a lag screw fixation, whether locking or nonlocking screws are used. For implantation, the fracture is reduced and fixed with one or more lag screws. The appropriately contoured plate is applied to the bone. Screws are inserted in a neutral mode. Depending on the plate design, bone quality, implant availability, and surgeon’s preference, fixed angle locking head screws, variable angle locking head screws, or nonlocking screws may be inserted. Every hole need not be filled if enough screws are inserted to obtain sufficient hold to maintain the reduction until the fracture heals.

[0139] Compression plates provide stability at fracture sites. If possible, the fracture is reduced and temporarily fixed with clamps. Typically, compression plating is used in transverse and short oblique fractures (< 30°). Fracture stability from interfragmentary compression results in direct bone healing. In certain embodiments, self-compressing plates, such as dynamic compressionplates, limited contact dynamic compression plates, or limited contact plates, or axial compression results from eccentric screw (load screw) insertion.

[0140] In certain embodiments, an articulated tension device provides mechanical compression or distraction before fixation with screws inserted in a neutral mode. As in other procedures, the fracture is reduced approximately and securely attaches a plate to one fragment. The device is anchored to the bone with a screw inserted through the articulated footplate. The hook on the device is inserted into the hole at the end of the plate. As the tensioning screw is then tightened, the two limbs of the device are pulled together, achieving compression at the fracture site. In oblique fractures, the plate creates an axilla following the same principle as prebent dynamic compression plates.

[0141] Bridge plating is used for multifragmentary long bone fractures where intramedullary nailing or conventional plate fixation, such as compression or protective plating, is unsuitable. The plate provides relative stability by fixation of the two main fragments, achieving correct length, alignment, and rotation. The fracture site is left undisturbed. Callus formation promotes fracture healing.

[0142] Bridge plates, like other plates, are often inserted through a minimally invasive approach to leave the fracture site as undisturbed as possible. Screws are either inserted through a limited approach, only exposing the plate sufficiently for screw insertion, or through small stab incisions. The least surgical disturbance to the fracture site occurs when a minimally invasive percutaneous technique is used for plate insertion. Especially with multifragmentary fractures, using an external fixator or distractor can provide alignment and temporary stability for bridge plating without disturbing the soft tissues at the fracture zone. Proximal and distal pins are inserted carefully to not interfere with the later plating procedure.

[0143] Long plates with a long working length allow the distribution of bending stresses over a long plate segment, and the stress per unit area is correspondingly low. This prevents high stress over the fracture site and reduces the risk of plate failure. Long plates also allow for a long lever arm, reducing the risk of screw pullout.

[0144] Buttress plates are often used to supplement lag screw fixation of metaphyseal shear or split fractures into the metaphyseal regions. The lag screws may be inserted either through or outside the buttress plate. The fracture is reduced and fixed with one or more lag screws following the standard technique.

[0145] In certain embodiments, a washer is used, for example, with osteoporotic bone. When used, the washer has a flat side, which rests on the bone, and a counter sunk side which accepts the screw head of screw cap. The washer prevents the screw form breaking through the thin cortex in the metaphysis and epiphysis by spreading the load over a larger area.

[0146] Where locking screws are used, such as those described herein, the bone-plate construct remains stable even if the plate does not directly contact the bone. Therefore, contouring does not need to be as accurate.

[0147] Either conventional or locking head screws may be used. When using a nonlocking plate and screws, the plate is precisely adapted to the bone; otherwise, the tightening of the screws may lead to loss of reduction. In nonlocking plate systems, screw loosening may also lead to loss of reduction.

[0148] The locking head screws described herein provide more stability in osteoporotic bone by reducing the risk of screw pullout and over-tightening of the screws. Well-reduced fractures stay reduced. In certain embodiments, the screw is unicortical, engaging only one cortex of the bone. In certain embodiments, the screw is bicortical, engaging both cortices of the bone. The plate does not need to be perfectly contoured to the bone. The plate is not pressed against the bone, so the periosteum is not compromised.

[0149] Screws are unlikely to loosen from the plate. Similarly, if a bone graft is screwed to the plate, a locking head screw will not loosen during graft incorporation and healing. A locking plate / screw system decreases the risk of inflammatory complications due to hardware loosening. Locking plate / screw systems provide more stable fixation than conventional nonlocking plate / screw systems.

[0150] Locking head screws are engaged in the plate, and the plate is not pressed against the bone. This reduces interference to the blood supply to the bone underneath the plate. The plate and screws provide adequate rigidity and do not depend on the underlying bone buttressing (load-bearing osteosynthesis). On each side of the fracture, the screws are locked into the plate and the bone. The result is a rigid frame construct with high mechanical stability (internalexternal fixator).

[0151] When using a locking plate / screw system, the plate does not have to be precisely adapted to the bone. When tightening a locking head screw, the screw does not cause a direct loss ofreduction as it tightens into the threaded plate hole and does not draw the bone fragments to the plate. In a locking system, the screw rarely loosens because the screw head is locked to the plate.Manufacturing

[0152] The devices disclosed herein can be manufactured using various methods. In some embodiments, manufacturing comprises machining, such as subtractive, deformative, or transformative manufacturing. In some embodiments, manufacturing includes cutting, grinding, rolling, forming, molding, casting, forging, extruding, whirling, grinding, cold working, or combinations thereof. In some embodiments, manufacturing includes a portion of the device formed by a medical machining process. In some embodiments, machining uses computer numerical control (CNC) high-speed milling machines, Swiss machining devices, CNC turning with living tooling, wire EDM 4th axis, and combinations thereof. In some embodiments, the manufacturing for fabricating a portion of the devices includes a finishing process, such as laser marking, tumble blasting, bead blasting, micro blasting, powder blasting, or combinations thereof.

[0153] In certain embodiments, the device is fabricated per instructions from a computer and processor based on the digital rendering and / or data of a selected configuration via additive manufacturing.

[0154] In some embodiments, additive manufacturing comprises 3-D printing. In some embodiments, additive manufacturing is chosen from fused deposition modeling, selective laser sintering, direct metal laser sintering, selective laser melting, electron beam melting, layered object manufacturing, stereolithography, and combinations thereof. In some embodiments, additive manufacturing comprises rapid prototyping, desktop manufacturing, direct manufacturing, direct digital manufacturing, digital fabrication, instant manufacturing, on- demand manufacturing, or combinations thereof.

[0155] In some embodiments, a portion of the device is manufactured by additive manufacturing and then mechanically attached to a surface of the device, for example, by welding, threading, adhesives, or staking.

[0156] In one embodiment, the device is configured based on imaging from the patient's anatomy. Suitable imaging techniques include, but are not limited to, X-ray, fluoroscopy, computed tomography (CT), magnetic resonance imaging (MRI), surgical navigation, bone density (DEXA), or acquirable 2-D or 3-D images of patient anatomy. Selected configurationparameters for the device are collected, calculated, or determined. Examples of configuration parameters include, but are not limited to, patient anatomy imaging, surgical treatment, historical patient data, statistical data, treatment algorithms, implant material, implant dimensions, porosity, and manufacturing method. In some embodiments, the configuration parameters comprise implant material and device porosity based on patient anatomy and surgical treatment. In some embodiments, porosity is selected. In some embodiments, the configuration parameter of the device is patient specific. In some embodiments, the configuration parameter of the device is based on a generic configuration and is not patient specific.

[0157] For example, a digital rendering or data of a device is generated for display from a graphical user interface or storage on a database attached to a computer and a processor. In some embodiments, the computer display via a monitor saves, digitally manipulates, or prints a hard copy of the digital rendering or data. In some embodiments, the device is designed virtually with a CAD / CAM program on a computer display. In some embodiments, the processor executes code stored in a computer-readable memory medium to execute one or more computer instructions, for example, transmitting instructions to an additive manufacturing device. In some embodiments, the database or computer-readable medium comprises RAM, ROM, EPROM, magnetic, optical, digital, electromagnetic, flash drive, semiconductor technology, or combinations thereof. In some embodiments, the processor instructs motors to control the movement and rotation of device components.

[0158] The screw is tested in cobalt chrome and meets American Society for Testing and Materials (ASTM) standard 543. ASTM standard 543 evaluates plastic materials for resistance to chemical reagents, including cast, hot-molded, cold-molded, laminated resinous products, and sheet materials. Three procedures are presented, two under practice A (Immersion Test) and one under practice B (Mechanical Stress and Reagent Exposure under Standardized Conditions of Applied Strain). These practices report changes in weight, dimensions, appearance, color, strength, and other mechanical properties. Standard reagents are specified to establish results on a comparable basis without precluding other chemical reagents pertinent to specific chemical resistance requirements. Provisions are made for various exposure times, stress conditions, and exposure to reagents at elevated temperatures. The type of conditioning (immersion or wet patch / wipe method) depends upon the end-use of the material.Method of Implantation

[0159] In certain embodiments, a method of implanting a reduction trauma screw comprises inserting a headless screw having at least one coupling structure at a proximal end into a borehole in a bone using a headless driver, and coupling a reduction cap to the inserted headless screw via a reduction driver loaded with the reduction cap, by using the headless driver to counter-torque against the reduction driver to engage the at least one coupling structure.

[0160] As used herein, “borehole” refers to a passage created in a bone or other substrate for receiving or guiding a medical device. In certain embodiments, boreholes are formed using drilling or reaming procedures to accommodate headless screws or other implants. Suitable examples include, but are not limited to, a cylindrical hole in the femur for intramedullary nails and a smaller aperture in vertebral bone for screw insertion.

[0161] As used herein, “reduction driver” refers to a specialized instrument configured to engage and manipulate a reduction cap for compressing or securing a headless screw. In certain embodiments, reduction drivers are equipped with features that apply controlled torque or allow counter-torque during screw insertion. Suitable examples include, but are not limited to, drivers with a T-handle design or a cannulated shaft that aligns with a guide wire for precise placement.

[0162] As used herein, “counter-torque” refers to the act of applying an opposing rotational force to offset or stabilize a primary rotation, particularly during the insertion or removal of threaded components. In certain embodiments, counter-torque is provided by a specialized driver that holds a headless screw in place while another driver turns a cap or fixation element. Suitable examples include, but are not limited to, two-handed systems in which one hand holds a stabilizing instrument and the other hand rotates a second instrument.

[0163] In certain embodiments, the method comprises choosing the at least one coupling structure from narrow threads, a finger-trap locking mechanism, or a spiral bayonet mechanism.

[0164] In certain embodiments, the method comprises using a finger-trap locking mechanism having a plurality of lattice fingers dimensioned to flex radially upon insertion of the headless screw.

[0165] In certain embodiments, the method comprises using a spiral bayonet mechanism that includes a helical groove on the proximal region of the headless screw and a matching protrusion formed on an interior surface of the reduction cap.

[0166] As used herein, “helical groove” refers to a spiraling channel or path formed along a shaft or component, configured to engage with a matching protrusion for rotational or locking functionality. In certain embodiments, helical grooves are positioned on a headless screw's proximal region to provide a bayonet-style lock with a reduction cap. Suitable examples include, but are not limited to, single-start or multi-start threads on a titanium shaft that secure a mating part through rotation.

[0167] In certain embodiments, the method further comprises aligning a drill guide or tissue protector before drilling the borehole in the bone.

[0168] In certain embodiments, the method further comprises inserting a guide wire down the bone, drilling with a cannulated drill bit inserted around the guide wire, and then removing the cannulated drill bit and the guide wire to form the borehole before inserting the headless screw.

[0169] In certain embodiments, the method comprises using a headless screw that includes a scaffold configured to promote bony in-growth through the screw, wherein the scaffold is chosen from a triply periodic minimal surface or a folded sheet scaffold.

[0170] In certain embodiments, the method comprises using a headless screw that further comprises a trephine channel configured to harvest autograft material during insertion.

[0171] As used herein, “trephine channel” refers to an internal passage configured to collect or retain tissue, such as bone or marrow, during insertion of a medical device. In certain embodiments, trephine channels are formed through the central portion of a screw to aid autograft harvesting and promote bone in-growth. Suitable examples include, but are not limited to, hollow cores in headless screws designed for cannulated drilling or vacuum-assisted graft retrieval. In certain embodiments, the method comprises loading the reduction cap onto the reduction driver and advancing until bone compression is achieved without rotating the headless screw further into the bone.

[0172] In certain embodiments, the method comprises accessing the bone percutaneously to insert the headless screw.

[0173] The disclosed method of implantation has the advantage of preventing overdrilling because the borehole needs only be drilled once rather than twice as in the conventional procedure. The bone harvesting features of the threads on the screw permit single drilling for insertion. Moreover, using insertion, the locking screw head engages and locks into the threadedplate hole. If necessary, the threaded plate hole also accepts nonlocking screws, which permit angulation. Tightening the screws “lag” the bone to the undersurface of the plate.Regenerative medicine

[0174] “Regenerative medicine” refers to a branch of translational research in tissue engineering and molecular biology that deals with replacing, engineering, or regenerating human cells, tissues, or organs to restore or establish normal function. This field holds the promise of engineering damaged tissues and organs by stimulating the repair mechanisms within the patient’s body to functionally heal previously irreparable tissues or organs. For example, during bone regeneration, new bone formation is primarily affected by physicochemical cues in the surrounding microenvironment. Tissue cells reside in a complex scaffold physiological microenvironment.

[0175] In certain embodiments, regenerative medicine is incorporated with the scaffolds or devices disclosed herein. Autogenous graft incorporation occurs in five stages: inflammation, vascularization, osteoinduction, osteoconduction, and remodeling.

[0176] Inflammation lasts for about 7 to 14 days. Initial insult to the local blood supply and decortications results in hematoma around the bone graft, in which inflammatory cells invade. The fibroblast-like cells in the inflammatory tissue transform into the fibrovascular stroma. Perioperative anti-inflammatory medications decrease fusion rates because of the inflammatory process.

[0177] Vascular buds appear in the fibrovascular stroma, resembling scar tissue formation during vascularization. Primary membranous bone forms near the decorticated bone. Next, minimal cartilage and endochondral ossification occur.

[0178] During osteoinduction at weeks 4 to 5, reparation comprises increased vascularization, necrotic tissue resorption, osteoblasts, and chondroblasts differentiation. In particular, stem cells differentiate into osteoblasts. New bone extends towards the central zone of the fusion mass. The cortical portion of the graft continues to resorb.

[0179] Osteoconduction is characterized by ingrowth into the host bone and creeping substitution. Osteoblasts create new bone while osteoclasts simultaneously resorb graft bone. A central zone of the endochondral interface is observed at the center of fusion mass, uniting the lower and upper halves of fusion. Pluripotent cells in this central zone differentiate into cartilaginous tissue with less vascularization.

[0180] During remodeling at weeks 6-10, a peripheral cortical rim forms around fusion. Bone marrow activity increases, forming secondary spongiosa. The cortical rim thickens. The trabecular process extends to the center of fusion. Remodeling typically completes one year after device implantation.

[0181] Pseudarthrosis (nonunion) was a leading cause of pain postoperatively and accounted for 45%-56% of revisions. Boney fusion directly correlates to successful clinical outcomes. Patients with pseudarthrosis were asymptomatic in about 30% of cases. Younger age has a significantly increased symptomatic pseudarthrosis rate (43.8 years vs. 52.1 years, p < 0.01).

[0182] In certain embodiments, bone marrow aspirate (BMA) with allograft substitutes autogenous bone graft in single-level revision posterolateral lumbar fusion (PLF). In certain embodiments, bone marrow aspirate with allograft is more cost-effective than recombinant human bone morphogenetic protein-2 (rhBMP). In certain embodiments, bone marrow-derived cell-enriched allografts compare to autografts in bone grafting and spinal fusion procedures. In certain embodiments, BMA increases the regenerative potential of corti cocancellous allogeneic bone grafts. When treating unicameral bone cysts, healing rates were high (98.7 %) for bone marrow with demineralized bone matrix injection.

[0183] When introducing elements of the present disclosure or the embodiments(s) thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.Example 1 - Finger-Trap Locking Mechanism

[0184] In certain embodiments, the reduction trauma screw comprises a finger-trap-style locking mechanism. A cap and a headless screw each comprise structures configured to lock together when axially press-fit. The cap has a perimeter or internal region with slender lattice “fingers,” printed or otherwise formed in a spring-like arrangement. These lattice fingers are dimensioned to flex radially outward or inward upon insertion of a complementary male portion of the screw shaft.

[0185] As the screw shaft is pushed in, the fingers temporarily deform, then snap back to a resting position, creating a press-fit interference. In some embodiments, each lattice finger measures about 100-300 microns thick. Sufficient resiliency can be provided in a metallic 3D- printed structure, such as titanium or a titanium alloy. When removal of only the cap is notneeded, the screw and cap combination can be extracted as a single unit, aiding explantation should revision be needed.

[0186] In some embodiments, the finger-trap locking mechanism may be combined with one or more scaffold features (e.g., a triply periodic minimal surface along the cap’s exterior) to promote osseointegration and bone in-growth. The internal geometry may include “windows,” fenestrations, or ports to simplify the delivery of biological agents into the screw or cap before or after installation.Example 2 - Spiral Bayonet Locking Mechanism

[0187] In another embodiment, the reduction trauma screw comprises a spiral bayonet mechanism configured to couple the reduction cap to the headless screw. A helical groove is formed on the screw’s proximal region, and a matching protrusion is formed on the interior surface of the reduction cap. During assembly, the reduction cap is pressed onto the screw’s proximal end and then rotated through a specific angular offset so that the matching features engage.

[0188] In certain embodiments, multiple repeats of the spiral groove may be formed around the cap-screw interface so that the shear forces are distributed over several interlocking regions. This arrangement can comprise four, six, eight, or more “starts” to the spiral, each located at a different circumferential position. Not wishing to be bound by theory, such a configuration may increase stability under load and reduce peak stresses at any single contact point.

[0189] As with other embodiments, the spiral bayonet locking mechanism may be printed or machined. A wide range of threads or lattice topographies can be combined with this approach, including, for example, diamond lattice or pseudorandom folded-sheet scaffolds, allowing the cap to incorporate open-porosity regions that encourage bony in-growth and minimize micromotion at the interface.

[0190] Any of the foregoing features described with respect to these examples (e.g., the latticebased finger-trap assembly or spiral bayonet mechanism) may be further combined, modified, or omitted to achieve the desired clinical performance. For instance, a hybrid arrangement may merge both finger-trap resiliency and a partial bayonet twist-lock interface. Some embodiments permit choosing from multiple geometries, angles, or lattice configurations so that a single type ofheadless screw can be used interchangeably with different caps, accommodating patient-specific anatomy and fixation requirements.

[0191] These examples are illustrative pathways by which the disclosed reduction trauma screws may achieve robust locking between screw and cap. Other designs, variants, or manufacturing techniques not explicitly described may similarly fall within the scope of the presently disclosed methods and devices.

[0192] Having described the disclosure in detail, it will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims.

[0193] Although the disclosure described herein is susceptible to various modifications and alternative iterations, specific embodiments thereof have been described in greater detail above. It should be understood, however, that the detailed description of the composition is not intended to limit the disclosure to the specific embodiments disclosed. Rather, it should be understood that the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the claim language.

[0194] All references, patents, or applications, US or foreign, cited in the application are because of this incorporated by reference as if written herein in their entireties. Where any inconsistencies arise, the material disclosed herein controls.

[0195] From the preceding description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

Claims

CLAIMSWhat is claimed is:

1. A reduction trauma screw, comprising: a headless screw having at least one coupling structure at a proximal end; and a reduction cap adapted to couple to the headless screw via the at least one coupling structure after the headless screw has been inserted into a substrate, wherein the at least one coupling structure is configured to provide a locking engagement.

2. The screw of claim 1, wherein the at least one coupling structure is chosen from narrow threads, a finger-trap locking mechanism, or a spiral bayonet mechanism.

3. The screw of claim 2, wherein the at least one coupling structure is a finger-trap locking mechanism, and each finger has a thickness between about 100 and 300 microns.

4. The screw of claim 2, wherein the at least one coupling structure is a spiral bayonet mechanism comprising a helical groove on the proximal region of the headless screw and a matching protrusion formed on an interior surface of the reduction cap.

5. The screw of claim 4, wherein the spiral bayonet mechanism comprises four or more starts, each located at a different circumferential position.

6. The screw of any one of claims 1-5, further comprising at least one scaffold on the reduction cap, the scaffold being configured to promote bony in-growth.

7. The screw of claim 6, wherein the scaffold comprises a triply periodic minimal surface having a repeating pattern.

8. The screw of claim 6, wherein the scaffold is a pseudorandom folded-sheet structure comprising a continuous sheet of topological genus-n.

9. The screw of claim 6, wherein the reduction cap further comprises one or more windows, fenestrations, or ports in fluid communication with the scaffold.

10. The screw of any one of claims 1-9, wherein at least one of the headless screw or the reduction cap is manufactured from a 3D-printed titanium alloy.11 . The screw of any one of claims 1-10, wherein the headless screw further comprises a trephine channel configured to harvest autograft material during insertion into the substrate.

12. The screw of any one of claims 1-11, wherein the at least one coupling structure is adapted so that the headless screw and the reduction cap can be removed together as a single unit for explantation.

13. A method of implanting a reduction trauma screw, comprising: inserting a headless screw having at least one coupling structure at a proximal end into a borehole in a bone using a headless driver; and coupling a reduction cap to the inserted headless screw via a reduction driver loaded with the reduction cap, by using the headless driver to counter-torque against the reduction driver to engage the at least one coupling structure.

14. The method of claim 13, wherein the at least one coupling structure is chosen from narrow threads, a finger-trap locking mechanism, or a spiral bayonet mechanism.

15. The method of claim 14, wherein the at least one coupling structure is a finger-trap locking mechanism comprising a plurality of lattice fingers dimensioned to flex radially upon insertion of the headless screw.

16. The method of claim 14, wherein the at least one coupling structure is a spiral bayonet mechanism comprising a helical groove on the proximal region of the headless screw and a matching protrusion formed on an interior surface of the reduction cap.

17. The method of any one of claims 13-16, further comprising aligning a drill guide or tissue protector before drilling the borehole in the bone.

18. The method of claim 17, further comprising inserting a guide wire down the bone, drilling with a cannulated drill bit inserted around the guide wire, and then removing the drill cannulated bit and the guide wire to form the borehole before inserting the headless screw.

19. The method of any one of claims 13-18, wherein the headless screw includes a scaffold configured to promote bony in-growth through the screw, and the scaffold is chosen from a triply periodic minimal surface or a folded sheet scaffold.

20. The method of any one of claims 13-19, wherein the headless screw further comprises a trephine channel configured to harvest autograft material during insertion.21 . The method of any one of claims 13-20, wherein the reduction cap is loaded onto the reduction driver and advanced until bone compression is achieved without rotating the headless screw further into the bone.

22. The method of any one of claims 13-21, wherein the bone is accessed percutaneously to insert the headless screw.

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