Composite porous intervertebral body implant, and method for manufacturing it

Abstract

A method of forming a composite titanium body for use in forming a spinal interbody implant includes selecting a metal alloy body, cutting top and bottom sections from the metal alloy body, and bonding a porous material to the cut-out top and bottom sections. Multiple sections may be cut from the composite titanium body, each having an anterior surface formed of the metal alloy, top and bottom sections formed of the porous material, and a middle section extending from the anterior surface to the posterior surface and formed of the metal alloy. Methods and devices for spinal interbody implants with fixation mechanisms to prevent bone screw backout are also described.

Description

Technical Field

[0001] The present disclosure generally relates to implants for the spine. More specifically, without limitation, the present disclosure relates to intervertebral spinal implants and methods of manufacturing intervertebral spinal implants.

Background Art

[0002] Spinal surgery may be used to treat various abnormalities such as degenerative disc disease, recurrent disc herniation, spinal instability, spondylolisthesis, pseudoarthrosis, osteomyelitis / discitis, postlaminectomy syndrome, and trauma. Spinal fixation procedures are typically used for intractable low back pain caused by degenerative disc disease and / or spinal instability. Fixation includes fixation of the painful spinal segment and promotion of bone growth across the entire fixed level. Anterior decompression and fixation are typically used for the cervical spine.

[0003] Since the clinical results of lumbar fixation correlate with the achievement of bone fusion, spinal fixation implants are often configured to promote bone ingrowth. It is likely to promote fixation and improve the lifespan of the implant by achieving bone bonding with an intervertebral implant and limiting subsidence, stress shielding, and related complications. In fact, improving bone ongrowth and ingrowth with an intervertebral implant may enhance fusion and limit pseudoarthrosis, stress shielding, subsidence, and implant malfunctions.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Titanium and its alloys are often chosen for intervertebral implant structures due to their excellent biocompatibility, robust repassivation resulting from TiO2 formation which provides superior corrosion resistance, and low density. While titanium alloys possess desirable biocompatibility and mechanical properties, further modifications are often required to support osseointegration. For example, modifications include surface roughness, surface morphology modification, heat treatment, alkali treatment, Na ion removal, porous material conversion, and / or HA coating. These modifications can enhance the potential for osseointegration and bioactivity. Porous titanium can be useful for osseointegration, but it also has limitations. For example, porous titanium is not as strong or durable as solid titanium.

[0005] Another problem with spinal implants is that bone anchors are sometimes used to fix the implant in place between adjacent vertebrae. Over time, microscopic movements of the vertebrae relative to the implant can cause the bone anchor to loosen and begin to retract from the vertebrae. In some cases, in addition to the implant potentially loosening and moving within the intervertebral space, the bone anchor itself may protrude and cause damage to the patient's sensitive tissues and organs.

[0006] Improvements to the implant design are needed to further enhance both the short-term and long-term stability of the implant and promote fusion. [Means for solving the problem]

[0007] In one embodiment, a method for manufacturing a composite intervertebral implant is disclosed, in which a metal alloy body having an upper surface and an opposite bottom surface is selected, a portion of the upper surface of the metal alloy body is cut or hollowed out, a portion of the bottom surface of the metal alloy body is cut or hollowed out, a porous metal is bonded to the upper surface, a porous metal is bonded to the bottom surface to form a composite metal alloy block, and the composite intervertebral implant is separated from the composite metal alloy block. In one configuration, the metal alloy includes a titanium alloy, and the porous metal includes porous titanium. In another embodiment, fusion bonding may be used to fuse the porous material to the metal alloy body.

[0008] Further disclosures herein include composite interbody implants, such as interbody implants formed from composite metal alloy blocks formed in the manner described herein. For example, an ALIF composite interbody implant system may comprise a body having an anterior and an opposite posterior surface, an upper portion and a bottom portion, with an intermediate portion extending through the body from the anterior to the opposite posterior surface, the anterior surface being formed of a titanium alloy, the upper and bottom portions being formed of porous titanium, and the intermediate portion being formed of a titanium alloy. In one configuration, the anterior and intermediate portions are formed from a single titanium alloy.

[0009] In yet another embodiment, a fixation mechanism for preventing retraction of bone anchors from a composite interbody implant is described. The composite interbody implant system may comprise a body having an anterior and an opposite posterior surface, an upper portion and a bottom portion, the middle portion extending through the body from the anterior surface to the opposite posterior surface, the anterior surface being formed of a solid metal alloy, the upper and bottom portions being formed of a porous metal, the middle portion being formed of a solid metal alloy, the anterior surface having at least one hole for receiving a bone screw, and the composite interbody implant system comprising at least one fixation mechanism for preventing retraction of the bone screw.

[0010] The fixing mechanism may have an axial channel provided proximal to the hole, and the fixing mechanism has a cylinder with an outwardly projecting tab, the cylinder being receivable into the axial channel, and the outwardly projecting tab extending into at least one hole. In one configuration, the outwardly projecting tab of the fixing mechanism further has an angled surface such that when a bone screw is inserted into at least one hole, the bone screw can deflect the outwardly projecting tab. After the outwardly projecting tab has been deflected by the bone screw, the outwardly projecting tab may be biased and extend into at least one hole.

[0011] In one configuration, the composite intervertebral implant system may have a front surface having a first hole for receiving a first bone screw and a first inwardly extending channel provided proximal to the first hole for receiving a first fixation mechanism, the front surface having a second hole for receiving a second bone screw and a second inwardly extending channel provided proximal to the second hole for receiving a second fixation mechanism, the first fixation mechanism having a cylinder receivable into the first inwardly extending channel and having an inner end and an outer end, and a tab projecting outward from the outer end of the cylinder and at least partially projecting into the first hole, the second fixation mechanism having a cylinder receivable into a second inwardly extending channel, and a tab projecting outward from the cylinder and at least partially projecting into the second hole.

[0012] In another embodiment, the outer end of the cylinder of the fixing mechanism is cut off so that the pressure of the inwardly moving first bone anchor pushes the tab of the first fixing mechanism out of the first hole, and the pressure of the inwardly moving second bone anchor pushes the tab of the second fixing mechanism out of the second hole. The tabs of the first and second fixing mechanisms are biased to protrude at least partially into the first and second holes, respectively.

[0013] In another embodiment, a cervical composite interbody implant is described, which may comprise a body having an anterior and an opposite posterior surface, and an upper and a bottom portion, wherein an intermediate portion penetrates the body and extends from the anterior surface to the opposite posterior surface, separating the upper and bottom portions, the anterior surface being formed of a solid metal alloy, the upper and bottom portions being formed of a porous metal, and the intermediate portion being formed of a solid metal alloy, the anterior surface having a first hole for receiving a first bone anchor and a second hole for receiving a second bone anchor, and the cervical composite interbody implant comprises a fixation mechanism for preventing the retraction of the first and second bone anchors from the first and second holes, respectively.

[0014] In another embodiment, the anterior surface of the cervical implant has a molded cavity for receiving a fixation mechanism, provided between a first hole and a second hole, the fixation mechanism having a rotatable stopper positioned in the molded cavity between the first hole and the second hole, the rotatable stopper having a first open position into which a bone anchor can be inserted and a second closed position into which a bone anchor cannot be inserted. In one configuration, the molded cavity may further have a further notch for receiving / engaging with an insert.

[0015] In one configuration, the body of the cervical implant has a vertical opening, the fixation mechanism further has a vertical pin, and the rotatable stopper has an opening for receiving the vertical pin to hold the rotatable stopper in place in the body. The rotatable stopper may have a first outward-extending arm and a second outward-extending arm, and the molded cavity has a first slot for the first outward-extending arm to rotate internally, and a second slot for the second outward-extending arm to rotate internally.

[0016] In another embodiment, the implant described herein may be cut / formed from a composite metal block formed using the method described herein. The implant cut / formed from a composite metal block formed using the method described herein has a solid metal front, with a solid metal middle portion extending from the front to the rear, and an upper and lower portion formed of a porous material. The upper and lower portions may be diffusion-bonded to the middle portion.

[0017] Other aspects of the disclosed subject matter, as well as the features and advantages of various aspects of the disclosed subject matter, should become apparent to those skilled in the art by considering the following description, the accompanying drawings and the accompanying claims. [Brief explanation of the drawing]

[0018] The following drawings show what are currently considered to be specific and typical configurations for carrying out the disclosed subject matter, and are not limited to embodiments that may be made in accordance with this disclosure. Components in the drawings are not necessarily shown to a relative scale. Similar reference numerals indicate corresponding parts across multiple drawings.

[0019] [Figure 1] This is a perspective view showing an example of a composite titanium body used to manufacture intervertebral body implants. [Figure 2] This is a cross-sectional view showing the titanium alloy body. [Figure 3] This is a cross-sectional exploded view showing the cut titanium alloy body and the porous materials on the upper and lower sides. [Figure 4] Figure 1 is a perspective cross-sectional view. [Figure 5] Figure 1 is a cross-sectional front view. [Figure 6] Figure 1 is a perspective view showing the composite titanium body, which has potential cutting marks for forming intervertebral implants from the composite titanium body. [Figure 7]A perspective view showing an exemplary ALIF intervertebral implant formed from a composite titanium body as described herein. [Figure 8] A side view showing the exemplary ALIF intervertebral implant of FIG. 7. [Figure 9] A perspective view showing the exemplary ALIF intervertebral implant of FIG. 7 with screws shown. [Figure 10] An exploded view of FIG. 9. [Figure 11] A front view showing the exemplary ALIF intervertebral implant of FIG. 8. [Figure 12] A cross-sectional view showing the exemplary ALIF intervertebral implant of FIG. 8 along line XII of FIG. 11. [Figure 13] A perspective view showing an exemplary fixation mechanism. [Figure 14] A perspective view showing an exemplary cervical intervertebral implant formed from a composite titanium body as described herein. [Figure 15] A side view showing the exemplary cervical intervertebral implant of FIG. 14. [Figure 16] A perspective view showing the exemplary cervical intervertebral implant of FIG. 14 with screws shown. [Figure 17] A plan perspective view showing the exemplary cervical intervertebral implant of FIG. 14 with screws shown. [Figure 18] A front view showing the exemplary cervical intervertebral implant of FIG. 14 with screws shown. [Figure 19] A cross-sectional view showing the cervical intervertebral implant of FIG. 14 along line XVIII of FIG. 18. [Figure 20] A perspective view showing another exemplary fixation mechanism. [Figure 21A] A perspective view showing an exemplary inserter. [Figure 21B] An enlarged view showing the distal end of the inserter of FIG. 21A. [Figure 21C] A cross-sectional view showing the distal end of the inserter of FIG. 21A. [Figure 22A]A perspective view showing another exemplary insert. [Figure 22B] This is an enlarged view showing the distal end of the insertion device in Figure 22A. [Figure 23A] This is an exploded perspective view showing another exemplary insert. [Figure 23B] This is an enlarged view showing the distal end of the insertion device in Figure 23A. [Figure 24] A perspective view showing an exemplary modular tip used with the insert shown in Figure 23A. [Figure 25] A perspective view showing another exemplary modular tip used with the insert in Figure 23A. [Figure 26] A perspective view showing another exemplary modular tip used with the insert in Figure 23A. [Figure 27] A perspective view showing another exemplary modular tip used with the insert in Figure 23A. [Modes for carrying out the invention]

[0020] Exemplary embodiments of the present disclosure are described below in detail with reference to the accompanying drawings. The advantages and features of the present disclosure and methods for achieving them will become apparent from the following description of the exemplary embodiments with reference to the accompanying drawings. Various embodiments described with reference to one drawing may coexist and / or be used together with embodiments shown in other drawings, and each element shown in multiple drawings may be described only once.

[0021] References to “one configuration,” “one embodiment,” “configuration,” or “embodiment” in the specification mean that certain features, structures, or characteristics described in relation to a configuration are included in at least one configuration, but it is not required that such features, structures, or characteristics be present in any particular configuration unless explicitly indicated in the claims that they are present. The expression “in one configuration” in various places does not necessarily limit the inclusion of certain elements of the present invention in one configuration; rather, the elements may be included in any other configuration or all of the configurations described herein.

[0022] The described features, structures, or properties of the configurations of the disclosed subject matter may be combined in any suitable manner in one or more configurations. As used herein and in the appended claims, singular nouns such as “a,” “an,” and “the” may include plural nouns unless clearly indicated in the context. Thus, for example, a reference to “blocks” of solid titanium may include one or more such blocks, and a reference to “pores” may include one or more such pores. Structural elements, components, and / or materials may be shown in common lists for convenience. However, these lists should be interpreted as if each element of the list were individually identified as a distinct and unique element.

[0023] In this specification, any component of a composite intervertebral implant is described as being joined or connected to one another, and such joining and connection may be achieved in any suitable way. Furthermore, such components may be integrated or dispersed in any suitable way. As used herein, “block” of a material means any mass of such material of any shape or size, such as brick-like bodies, sheets or other lumps of such material.

[0024] This disclosure generally relates to a method for manufacturing a composite interbody implant. The composite interbody implant may be formed of a first part comprising a metal alloy which may be completely or substantially non-porous, and a second part comprising a porous material. In one configuration, as shown in Figure 1 and described in more detail below, the composite interbody implant is formed from a composite material brick or body 10 comprising a metal alloy brick or body 10 to which a porous material 15 is bonded or otherwise attached, with portions of the apex and base removed.

[0025] Any suitable metal or metal alloy, including but not limited to stainless steel, cobalt-chromium, titanium (Ti), titanium alloys, shape memory alloys, such as NiTi, tantalum (Ta), niobium (Nb), zirconium (Zr), and platinum (Pt), may be used for the metal alloy body 10 of the composite intervertebral implant. Intervertebral implants are typically formed from metals and metal alloys, including titanium, tantalum, titanium alloys, cobalt-chromium, and alloys thereof. Exemplary cobalt-chromium materials include CoCrMo alloy. Exemplary titanium alloys for use in accordance with this disclosure include Ti6AI4V. Exemplary stainless steel materials for use in accordance with this disclosure include austenitic stainless steel, particularly types 316 and 316L, as well as nickel-free stainless steel. Titanium is a physiologically inert transition metal with corrosion resistance and high rigidity, thus enhancing its usefulness in intervertebral implants. Titanium also possesses unique osseointegration capabilities. Furthermore, the anatomical position of intervertebral implants made from titanium can be easily analyzed using conventional imaging methods.

[0026] The porous material 15 may be any suitable porous metal or metal alloy. For example, the porous metal or metal alloy may be selected from, but is not limited to, stainless steel, cobalt-chromium, titanium (Ti), titanium alloys, shape memory alloys, such as NiTi, tantalum (Ta), niobium (Nb), zirconium (Zr), and platinum (Pt). Typical metals and metal alloys may include titanium, tantalum, titanium alloys, cobalt-chromium, and their alloys. The porous material may be manufactured by any suitable method, and in one configuration, the porous material may be manufactured by bonding together thin sheets of metal or metal alloy, in which case the sheets are made porous using photolithography to form a uniform pore pattern in each sheet. The porous sheets may be bonded using methods such as diffusion bonding. Other methods may be used further, and the porous structure of the porous material 15 may have a randomized pore pattern or a repeating pore pattern. The porous material 15 may be characterized by interconnected pores or openings.

[0027] The porous material 15 may have pores with diameters in the range of, for example, about 100 μm to about 2 mm, about 100 μm to about 1 mm, about 200 μm to about 900 μm, or about 300 μm to about 800 μm. The pore diameter may have an average pore diameter of about 300 μm to about 800 μm, about 400 μm to about 700 μm, or about 500 μm to about 600 μm. The pore diameter distribution may be unimodal or bimodal. Any suitable pore shape and configuration may be used, such as spherical or partially spherical pores, cylindrical, cubic, conical, pyramidal, or polyhedral pores with repeating or random patterns. The porous material 15 may further have porosity suitable for promoting osseointegration. For example, the porous material may have an open area ratio of about 30% to about 80%. In some configurations, the porous material may have an open area ratio of more than 50%, more than 60%, more than 70%, or more than 75%.

[0028] The porous material 15 may be attached to the non-porous metal alloy body 10 in any suitable manner. In one configuration, the metal alloy body 10 may initially have one or more parts removed, for example by cutting or hollowing out a portion of the metal alloy body 10. Figure 2 is a cross-sectional view of a metal or metal alloy body 10 having a rectangular cross-section. In this configuration, a body 10 having a substantially brick-like shape is used, but other shapes and sizes of body 10 may be used. The body may have a top surface 18 and an opposite bottom surface 20.

[0029] As shown by the dashed line 24, a portion of the top surface 18 of the main body 10 may be cut out, hollowed out, or otherwise removed to form an upper cavity 27 (see Figure 3). Similarly, as shown by the dashed line 30 in Figure 2, a portion of the bottom surface 20 of the main body 10 may be cut out, hollowed out, or otherwise removed to form a bottom cavity 33 (see Figure 3). These cavities can then be filled with porous material. Figure 3 is an exploded cross-sectional view of the main body 10 having the upper cavity 27 and the bottom cavity 33 and the porous material 15 that fills each cavity.

[0030] The porous material 15 may be joined to the metal alloy body 10 in any suitable way. Diffusion bonding may be used, for example, without limitation. Because diffusion bonding is a solid bonding technique, the original bond line becomes undetectable. The metal parts being joined undergo only minute deformation, and the bonded area is homogeneous without secondary material or liquid phase. High temperature and high pressure are often used in diffusion bonding to achieve atomic-level welding between the metal parts. When two surfaces are joined under high temperature and high pressure, the material begins to diffuse over time beyond the boundary of the contacting surfaces, mixing the material boundaries to form a bonded area.

[0031] The composite metal alloy block 12 disclosed herein may be formed by diffusion bonding of an aggregate of a first portion of a metal alloy body 10 (with the top and bottom portions already removed), a porous material 15 in the upper cavity 27 of the metal alloy body 10, and a porous material 15 in the bottom cavity 33 of the metal alloy body 10 (see Figures 4-5). These layers of porous material 15, metal alloy body 10, and porous material 15 may be diffusion bonded by placing the layers in a die and applying heat and pressure. As described above, diffusion bonding at the atomic level promotes bonding of surfaces in contact with each other, resulting in nearly 100% bonding.

[0032] Diffusion bonding for forming the composite metal alloy block 12 may be performed before forming the intervertebral implant from the composite metal alloy block 12. A composite metal alloy block 12 of any suitable shape and size may be used, and a portion of any suitable shape and size may be cut from the body 10 to form the upper cavity 27. The porous material used to fill the upper cavity may have a depth greater than the depth of the upper cavity 27 so as to extend beyond the upper side 18 of the metal alloy body 10. In other configurations, the depth of the porous material 15 used to fill the upper cavity 27 may be the same as the depth of the upper cavity 27 or less than the depth of the upper cavity 27.

[0033] Similarly, the bottom cavity 33 may be cut out from the main body 10. The bottom cavity 33 may have any suitable shape and size. The porous material 15 used to fill the bottom cavity 33 may have a depth greater than the depth of the bottom cavity 33 so as to extend below the bottom surface 20 of the metal alloy main body 10. In other configurations, the depth of the porous material 15 used to fill the bottom cavity 33 may be the same as the depth of the bottom cavity 33 or less than the depth of the bottom cavity 33.

[0034] After the composite metal alloy block 12 is formed, one or more composite intervertebral implants may be cut from the composite metal alloy block 12. Alternatively, the portion (including the metal alloy body 10 and the porous material 15) may be cut first and then diffusion-bonded together. A single composite metal alloy block 12 can be cut into multiple parts, as shown in Figure 6, and each part can be used to form a composite intervertebral implant. When the composite metal alloy block 12 is cut as shown by the dashed lines in Figure 6, that is, when the composite metal alloy block 12 is cut continuously, each intervertebral implant has a front surface formed of the non-porous metal alloy body 10, and upper and lower portions formed of the porous material 15, and it is recognized that the middle portion of the metal alloy body 10 extends from front to back through the intervertebral implant.

[0035] After cutting the composite metal alloy block 12, each part of the composite metal alloy block may be further formed to enhance the functionality of the composite intervertebral body implant by adding features to form a desired type of intervertebral body implant. Any desired type of intervertebral body implant may be formed, and the size, shape, and other features of the intervertebral body implant may be customized.

[0036] For example, an anterior lumbar interbody fixation implant may be formed with a general trapezoidal shape. A specific example of such an implant 40 is shown in Figures 7-8. The implant body 42 is defined by a general rectangular front surface 45, a tapered rear surface 47, and a side wall extending between the front surface 45 and the rear surface 47. For example, if the front surface 45 is cut from a composite metal alloy block 12 as described above, the front surface 45 may be formed of a metal alloy. The front surface 45 may have one or more holes or openings extending through the front surface, so the holes may be reinforced by using a metal alloy (rather than porous metal or porous metal alloy). Compared with porous metal or porous metal alloy, a solid metal alloy front surface may be able to withstand the load applied during implantation more effectively.

[0037] The front surface 45 of the implant body 42 extends from the lower surface 49 to the upper surface 51 and from the front of the front surface 45 toward a tapered rear surface 47. A hollow internal chamber 52 is defined within the inner circumference of the implant body 42. The front surface 45 may extend posteriorly to partway to the hollow internal chamber 52, to the vicinity of the hollow internal chamber 52, or from the anterior end to at least partway to the hollow internal chamber 52. Furthermore, the hollow internal chamber 52 may be filled with spongy autogenous bone graft, allograft, DBM, porous synthetic bone graft substitute, BMP, or a combination of these materials (collectively referred to as bone graft material) to promote osseointegration. In other configurations, the body may be substantially solid and may not include the hollow internal chamber 52.

[0038] In one embodiment, the osseointegration capability of the implant 40 is further enhanced by coating at least a portion of its outer surface with a growth-promoting material, such as crystalline nanoparticles. Suitable crystalline nanoparticles include hydroxyapatite ("HA"), tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate, HA carbide, fluoroapatite, magnesium-doped apatite, strontium apatite, titanium dioxide, yttrium oxide, zirconium oxide, and / or combinations thereof. In one configuration, at least a portion of the outer surface of the implant 40 is coated with the growth-promoting material. In another configuration, all or substantially all of the outer surface of the implant 40 is coated with the growth-promoting material.

[0039] The implant 40 has an upper portion 55 and a lower portion 60, both of which taper toward the rear surface 47. Both the upper portion 55 and the lower portion 60 may be formed of a porous material 15. Other types of materials may be used further. Furthermore, an intermediate portion 64 of the implant body 42 may extend from the front surface 45 to the rear surface 47, penetrating the center of the implant body 42. In one configuration, the intermediate portion 64 is formed of a titanium alloy (such as titanium from the titanium body 10) and separates the upper portion 55 and the lower portion 60. The upper portion 55 may be connected to the upper surface of the intermediate portion 64, and the lower portion 60 may be connected to the bottom surface of the intermediate portion 64. For example, the upper portion 55 and the lower portion 60 may be connected to the intermediate portion 64 by diffusion bonding as described above. If the implant body 42 is formed of a composite metal alloy block 12 as described above, the porous upper portion 55 and the lower portion 60 may be diffusion bonded to the intermediate portion 64 of the metal alloy, respectively.

[0040] In the illustrated embodiment, the upper surface 51 and the lower surface 49 define a plurality of serrated notches 68. The serrated notches 68 are defined by both the solid front surface 45 and the porous upper portion 55 and lower portion 60. In other configurations, the upper and lower surfaces may be relatively smooth, or they may have other bone engagement features configured to reduce sliding or movement of the intervertebral implant 40 relative to the vertebral bone.

[0041] The anterior surface 45 of the implant 40 has multiple holes through which threads (not shown in Figures 7-8) extend to secure the implant 40 to the vertebral body. Further voids / slots may be provided to receive instruments used to insert the implant 40 and may have a shape and size that engages with the insertion instruments. The implant 40 may further have a transverse opening 70 near the posterior surface 47. The transverse opening 70 can enhance the visibility of imaging of the implant 40 during surgical procedures, ensuring proper placement and insertion of the implant and further improving the postoperative evaluation of implant fixation.

[0042] The front surface 45 of the implant body 42 may have one or more holes for receiving screws to secure the implant body 42 in place. In the exemplary configuration shown in Figures 9-10, an angled first hole 73 and an angled second hole 75 may be provided for receiving bone anchors such as bone screws (bone screws 79, 81 are shown in Figures 9-10). Although bone screws are illustrated in this configuration, any type of bone anchor is conceivable. The first hole 73 and the second hole 75 may have any shape, size and opening suitable for receiving the desired type of bone anchor. In the configuration shown in Figures 9-10, the first hole 73 and the second hole 75 may be formed to penetrate the front surface 45 and extend to the outside of the upper surface 51 of the implant body 42 of the implant 40.

[0043] Similarly, a third hole 90 may be provided between the first hole 73 and the second hole 75. The third hole 90 may extend from the front of the front surface 45 to the outside of the lower surface 49 of the main body. In the exemplary configurations shown in Figures 7-8, the third hole 90 is larger than the first hole 73 and the second hole 75 and is configured to receive a cannula-type bone screw. In one configuration, only two holes may be provided in the main body 42 of the implant 40, while in another configuration, four or more holes may be provided as desired for fixing the implant 40 to the vertebral bone.

[0044] In one configuration, one or more holes in the front surface 45 may have further internal threads to engage with the threads of the bone screw. In other configurations, the holes may not have threads. In one particular configuration of the screw holes, the bone screws 79, 81 have heads that are at least partially threaded. The threaded heads of the bone screws 79, 81 and the threads of the first hole 73 and the second hole 75 may be configured to have a certain amount of clearance between the male and female threads. As shown in the cross-sectional view of Figure 12, the female thread 85 of the first hole 73 matches the pitch of the male thread 89 of the transverse screw 79. The clearance 92 between the female thread 85 and the male thread 89 allows the surgeon to control the angle of the transverse screw 79. By providing a gap between the male thread 89 and the female thread 85, the surgeon can further delay the screw, meaning that the surgeon can compress the implant 40 to the upper and / or lower vertebrae by rotating the bone screw 79 beyond the range necessary to reduce the distance between the implant 40 and the upper and / or lower vertebrae.

[0045] In some configurations, the implant may further have a fixation mechanism to prevent the retraction of the bone anchor. (Shown in Figures 9-10, which show two fixation mechanisms with respect to their placement in the implant 40, and in Figure 13, which shows the fixation mechanism alone.) One exemplary configuration has a fixation mechanism generally reference numbered 95, which has a cylinder 93 having an inner end 94 and an outer end 96, along with a tab 98 projecting outward from the outer end 96. The cylinder 93 of the fixation mechanism 95 extends through the axial channel 100 of the implant body 42 and may further be held in place in the axial channel 100 by a vertical pin 102 (Figure 10). Since the axial channel 100 is proximal to holes for the bone anchor (e.g., holes 73, 75), the tab 98 projecting outward from the fixation mechanism 95 extends into the holes, as will be described in more detail below. The axial channel 100 may extend rearward from the front surface 45, substantially perpendicularly from a line tangent to the front surface 45, or at an angle. The axial channel 100 may have a diameter slightly larger than the diameter of the cylinder 93 so that the cylinder 93 of the fixing mechanism 95 fits snugly into the axial channel 100. To ensure that the fixing mechanism 95 is securely held in place within the implant body 42, a pin 102 may be inserted perpendicularly through the upper surface 51 of the implant body 42 into a vertical hole 97 in the inner end 94 of the cylinder 93 of the fixing mechanism 95.

[0046] As shown in Figure 13, in an exemplary embodiment of the fixing mechanism 95, an outward-extending tab 98 is provided at the outer end 96. When the cylinder of the fixing mechanism 95 is positioned in the channel 100, the outward-extending tab 98 extends into the hole for receiving the bone screw. The tab 98 may further have an angled front surface. Furthermore, a portion of the cylinder 93 may be cut off proximal to the outer end 96. The angled surface and cut-off of the cylinder may allow the tab 98 to deform outward from the hole, and when the bone anchor is inserted (without the tab 98 blocking the hole), the bone anchor may pass through the tab 98. Once the head of the bone anchor has passed through the tab 98, the tab 98 is biased back into place in the hole and engages with the head of the screw, preventing the screw from retracting.

[0047] During use, the bone screw 79 is first introduced into the hole 73 until the head of the bone screw is pressed against the tab 98 projecting outward from the fixing mechanism 95. Due to the angled surface of the outwardly projecting tab 98, the head of the bone screw can push the tab 98 outward and move beyond it. Once the screw head has passed the tab 98, the tab 98 is biased back into place (now between the head of the bone screw and the entrance to the hole 73) and engages with the head of the bone screw, preventing the bone screw from retracting by physically preventing the bone screw 79 from retracting out of the hole 73. It is recognized that other types of fixing mechanisms may be used to further prevent the screw from retracting.

[0048] Referring to Figures 14-15, an exemplary configuration of a cervical implant 140 is shown, which may be formed from a composite metal alloy block 12 as described herein. The cervical implant 140 may comprise a general D-shaped body 142. The implant body 142 is defined by a general rectangular front surface 145, a tapered rear surface 147, and a side wall extending between the front surface 145 and the rear surface 147. For example, if the front surface 145 is cut from a composite metal alloy block 12 as described above, the front surface 145 may be formed from a titanium alloy. The front surface 145 of the implant body 142 extends from the lower surface 149 to the upper surface 151 and extends from the front of the front surface 145 toward the tapered rear surface 147. A hollow internal chamber 152 is defined within the inner circumference of the implant body 142. The metal alloy front 145 may extend partway into the hollow internal chamber 152, to the vicinity of the hollow internal chamber 152, or from the front end to at least partway into the hollow internal chamber 152. Furthermore, the hollow internal chamber 152 may be filled with spongy autologous graft, allograft, DBM, porous synthetic bone graft substitute, BMP, or a combination of these materials (collectively referred to as bone graft material) to promote osseointegration. In other configurations, the body is solid and does not include the hollow internal chamber 152.

[0049] The cervical spine implant 140 has an upper portion 155 and a lower portion 160, both of which taper toward the posterior surface 147. Both the upper portion 155 and the lower portion 160 may be formed of a porous material 15. Other types of materials may be used further. Furthermore, an intermediate portion 164 of the body 142 may extend from the front surface 145 to the posterior surface 147, passing through the center of the body 142. In one configuration, the intermediate portion 164 is formed of a metal alloy (such as titanium from the titanium body as described above) and separates the porous upper portion 155 and the porous lower portion 160. The upper portion 155 may be connected to the upper surface of the intermediate portion 164, and the lower portion 160 may be connected to the bottom surface of the intermediate portion 164. For example, the upper portion 155 and the lower portion 160 may be connected to the intermediate portion 164 by diffusion bonding as described above. If the implant body 142 is formed from a composite metal block 12 as described above, the porous upper portion 155 and lower portion 160 may be diffusion-bonded to the intermediate portion 164 of the metal alloy, respectively.

[0050] In the particular configuration shown, the lower surface 149 and upper surface 151 of the main body 142 define a number of recesses 168. The recesses 168 are defined by both the solid front surface 145 and the porous upper portion 155 and lower portion 160. In other configurations, the upper and lower surfaces may be relatively smooth, or they may have other bone engagement features configured to reduce sliding or movement of the cervical implant 140 relative to the vertebrae.

[0051] The anterior surface 145 of the cervical implant 140 has several cavities through which screws (not shown in Figures 14-15) extend to secure the implant to the cervical spine. Further cavities / slots may be provided for inserting the cervical implant 140 and / or for receiving instruments used to receive the fixation mechanism 195, as described below. In the exemplary configuration shown in Figures 14-15, a molded cavity 200 for receiving the fixation mechanism is provided, and a notch 211 for receiving the insertion instrument is provided.

[0052] The front surface 145 of the implant body 142 may have one or more holes for receiving screws to fix the implant body 142 in place. In the exemplary configuration shown in Figures 14-15, an angled first hole 173 and an angled second hole 175 may be provided for receiving cervical bone screws (cervical bone screws 179, 181 are shown in Figures 16-19). The first hole 173 and the second hole 175 may have any shape, size and opening suitable for receiving the bone screws or other desired types of bone anchors. In the configuration shown in Figures 14-15, the first hole 173 is formed to extend through the front surface 145 and outward from the bottom surface 149 of the implant 140. The second hole 175 is formed to extend through the front surface 145 and outward from the top surface 151 of the body 142 of the cervical implant 140. In one configuration, the first hole 173 and the second hole 175 may further have threads for engaging with the threads of the bone screws 179 and 181. In other configurations, the first hole 173 and the second hole 175 may not have threads.

[0053] If screw engagement between bone screws 179, 181 and the body 142 is desired, the engaging threads of bone screws 179, 181 may be provided at least partially on the respective heads of bone screws 179, 181. In one embodiment, the threaded heads of bone screws 179, 181 and the threads of the first hole 173 and the second hole 175 may be configured to have a certain amount of clearance between the male and female threads. By providing a clearance between the threads of bone screws 179, 181 and the threads of holes 173, 175, the surgeon can control the angle of the bone screws 179, 181 and further retard the bone screws, that is, the surgeon can compress the implant 140 against the upper and / or lower vertebrae by rotating the bone screws 179, 181 beyond the range necessary to reduce the distance between the implant 140 and the upper and / or lower vertebrae.

[0054] The cervical implant 140 may further comprise one or more fixation mechanisms to ensure that the bone anchor does not retract. A fixation mechanism 195 may be provided, as shown in Figures 16-20. In the particular configuration shown, the front surface 145 of the cervical implant body 142 may have a molded cavity 200 for receiving the fixation mechanism 195. The molded cavity 200 may be located between a first hole 173 and a second hole 175. The molded cavity 200 may have a first slot 204 proximal to the first hole 173 and extending at least partially into the first hole 173, and a second slot 208 proximal to the second hole 175 and extending at least partially into the second hole 175 (Figure 16). The first slot 204 and the second slot 208 may each receive the arms of the fixation mechanism 195, as described below. The molded cavity 200 may further have one or more additional notches 211 for receiving an insert (exemplary inserts are described below in relation to Figures 21A-27). The body 142 may further have a vertical opening 215 extending from the top surface 151 for receiving a vertical pin 218 to hold the fixing mechanism 195 in place.

[0055] The fixing mechanism 195 may consist of a rotatable stopper 220 that can be received into the molded cavity 200 of the implant body 142. The rotatable stopper 220 may have a first arm 224 extending outward and a second arm 227 extending outward. In one configuration, the first arm and the second arm may be directly opposite each other. In other configurations, one arm or three or more arms may be provided. The first arm 224 extending outward may rotate within a first slot 204 of the molded cavity 200, and the second arm extending outward may rotate within a second slot 208 of the molded cavity 200. The rotatable stopper 220 may have a first open position into which a bone anchor can be inserted, and a second closed position into which a bone anchor cannot be inserted. In the specific configuration shown in Figures 16-19, the first slot 204 allows the outward-extending first arm 224 to rotate from a closed position of approximately 180 degrees to an open position of approximately 270 degrees. Similarly, the second slot 208 allows the outward-extending second arm 227 to rotate from a closed position of approximately 0 degrees to an open position of approximately 45 degrees. The rotating stopper 220 extends into one or more holes in the second closed position, but not into one or more holes in the first open position. In the closed position, the outward-extending first arm 224 and the second arm 277 extend at least partially into the first hole 173 and the second hole 175, respectively. Due to this at least partial blocking of the holes, any bone anchors placed in the holes are physically blocked by the outward-extending arms of the rotating stopper 220 and cannot retract.

[0056] To hold the rotating stopper 220 in place on the body 142 of the cervical implant 140, the body 142 may have a vertical opening 215 extending downward from the upper surface 151 to receive a vertical pin 218. The rotating stopper may have an opening 225 or slot for receiving the vertical pin 218 (see Figure 20). The opening 225 may allow the rotating stopper 220 to be held in place even if it rotates between open and closed positions relative to the vertical pin 218.

[0057] During use, the surgeon may first position the cervical implant body 142. For example, an insert having a shape that engages with the notch 211 and / or a screw that engages with any threaded portion of the rotary stopper 220 may be used. Next, the surgeon may confirm that the rotary stopper 220 is in the released position with the first and second outward-extending arms each rotated outward from the hole. With the rotary stopper in the open position, the surgeon may introduce one or more bone anchors through the hole. Once the surgeon is confident that the bone anchors and the implant body are correctly positioned, the surgeon may then rotate the rotary stopper 220 to the closed position. Again, an insert may be used to rotate the rotary stopper. In the closed position, the outward-extending arms of the rotary stopper can prevent the bone anchor from retracting from the hole.

[0058] Figure 21A shows one aspect of the insert 300, which has a distal end 304 configured to engage with a suitable implant, such as the implant 40 described herein, by having an implant engagement mechanism 310 (shown in more detail in Figure 21B). The insert 300 further has a proximal end 313 having a handle engagement portion 317 and a knob 320 configured to engage with and disengage from an implant. An elongated shaft 325 is provided between the proximal and distal ends. The proximal end 313 further has a fixing mechanism 328 configured to optionally maintain the implant engagement mechanism 310 in a fixed configuration. The knob 320 is mechanically connected to the elongated shaft 325 such that the rotation of the knob 320 causes the inner shaft contained within the elongated shaft 325 to move parallel to the elongated shaft 325, so that the implant engagement mechanism 310 opens and closes in the direction of parallel movement of the inner shaft.

[0059] Figures 21B and 21C show in more detail some features of the implant engagement mechanism 310, including the lateral tongue-shaped body 332, which is defined by the base portion 335, the arm 338, and the internal projection 344 (Figure 21C), respectively. The implant engagement mechanism 310 is contained within the housing 337 and is mechanically connected to the internal shaft 340 as indicated above. Each base portion 335 has an angled or curved slot 349 that engages with a pin 354 located within the housing 337 and fixed to the housing 337. As the internal shaft 340 moves distally, each base portion 335 is pushed distally, and as the slot moves along the pin 354, each base portion 335 moves along the path defined by the slot 349. In this illustrated configuration, the distal movement of the inner shaft 340 opens the implant engagement mechanism 310, and opening the implant engagement mechanism 310 may be necessary to receive the implant.

[0060] The implant may be secured to the insert 300 by rotating the knob 320 to cause a proximal translation of the internal shaft 340, thereby closing the implant engagement mechanism 310 around at least a portion of the implant and engaging the internal projection 344 with the corresponding surface of the implant. Those skilled in the art will recognize that opening and closing the implant engagement mechanism 310 involves proximal and distal translation of the implant engagement mechanism, respectively. Such translation may be useful when removing the implant at a desired position in the patient's spine. In other words, once the desired position is reached, the implant engagement mechanism 310 is opened, and the implant engagement mechanism releases the implant, causing the implant engagement mechanism to push the implant slightly distally and the implant engagement mechanism to push proximal away from the implant, thereby removing the insert 300. Such a configuration is advantageous because it can assist the surgeon when removing the insert 300 while maintaining the implant in the desired position.

[0061] Figure 22A shows another embodiment of the insert 400, which has a handle 417 and a knob 420 at its proximal end 413 and an implant engagement mechanism 410 at its distal end. An elongated shaft 425 connects the proximal and distal ends.

[0062] Figure 22B is an enlarged view showing the distal end 403 of the insert 400, indicating that the implant engagement mechanism 410 has a pair of distally extending projections 444 and an engagement rod 447. The engagement rod 447 is the distal end of a rod that extends proximally through an elongated shaft 425 for mechanical connection to the knob 420. Therefore, rotation of the knob 420 rotates the engagement rod 447, which has threads that engage with a threaded hole in the implant, such as the threaded hole of the rotatable stopper 220 of the cervical implant 140. The projections 444 are configured to engage with a corresponding shape of the implant to stabilize the implant so that the engagement rod 447 can screw into the implant. For example, the projections 444 may be configured to engage with a notch 211 of the implant 140 or a similar shape of a different implant.

[0063] In one embodiment, the projection 444 is configured to prevent rotation of the implant's fixation mechanism while the insert 400 is engaged with the implant. For example, Figure 18 shows that when the projection 444 is inserted into the notch 211, the rotating retainer 220 has a pair of corrugated edges aligned with the notch 211 so that rotation of the rotating retainer 220 is prevented or made more difficult. Such a configuration is advantageous because it can prevent the rotating retainer from unintentionally closing before the bone screws 179, 181 are inserted.

[0064] Figure 22B further shows that the distal end 403 of the insert 400 has a stopper 450, in this illustrated embodiment, the stopper 450 is provided such that its distal surface is continuous with the distal surface of the implant engagement mechanism 410. The stopper 450 may be used to guide the surgeon or other user when placing and positioning the implant in the intervertebral disc cavity. For example, the stopper 450 may be used to abut against the upper or lower vertebral body to prevent the implant from being inserted too far into the intervertebral disc cavity. Thus, those skilled in the art will understand that the stopper 450 may be located at the most distal position of the insert 400, or slightly proximal to the most distal position so that the surgeon can insert the implant slightly deeper into the intervertebral disc cavity. Those skilled in the art will further understand that the insert 400 may not include a stopper at all to maximize the maneuverability of the surgeon or user.

[0065] Figure 23A shows another embodiment of the insert 500, which, like the insert 400, has a proximal end 513 with a handle 517 and a knob 520, but the distal end 504 of the insert 500 is configured to receive various modular tips (see Figures 24-26), which are described in more detail below. Specifically, the insert 500 has an elongated shaft 525 extending from the handle 517, and the distal end of the elongated shaft 525 has an opening 554 configured to receive an extension of a modular tip. Figure 23B shows that the opening 554 has a pair of flexible members 558 that releasably receive the respective protrusions of the extension of the modular tip. Similar to the insert 400, the insert 500 has an engaging rod 547 that is mechanically connected to the knob 520 and extends distally through the elongated shaft 525. However, unlike the insert 400, the engaging rod 547 extends well beyond the distal end of the elongated shaft 525 so that its modular tip penetrates and extends beyond the portion that is fixed to the insert 500 at the opening 554.

[0066] Figure 24 shows an embodiment of the modular tip 560. The modular tip 560 resembles the distal end of the insert 400 in that it has a pair of distally extending projections 544, but the modular tip 560 does not include a stopper. Furthermore, the modular tip 560 has a pair of gripping surfaces 563 to facilitate attachment and detachment of the modular tip 560 to the opening 554 of the insert 500. The modular tip 560 further has an extension 566 having a pair of projections or protrusions 569 configured to receive the flexible member 558 of the insert 500. The modular tip 560 further has a lumen 572 extending from the distal end to the proximal end, the lumen 572 configured to receive the engagement rod 547 of the insert 500.

[0067] Figure 25 shows another embodiment of the modular tip 570, which, like the modular tip 560, has a pair of distally extending projections 544a, a pair of gripping surfaces 563a, an extension 566a with projections 569a, and a lumen 572a for receiving the engaging rod 547. However, the modular tip 570 has a stopper 550, which in this illustrated embodiment is at a slight angle to the imaginary line between the pair of distally extending projections 544a.

[0068] Figure 26 shows another configuration of the modular tip 580, which, like the modular tip 580, has a pair of distally extending projections 544b, a pair of gripping surfaces 563b, an extension 566b with projections 569b, and a lumen 572b for receiving the engaging rod 547. The modular tip 580 has a stopper 550a, which is angled slightly with respect to the imaginary line between the pair of distally extending projections 544b, similar to the stopper 550 shown in Figure 25. Furthermore, the stopper 550a is positioned slightly proximal to the most distal surface of the modular tip 580.

[0069] Figure 27 shows another configuration of the modular tip 590, which, like the other modular tips, has a distally extending projection 544c, an extension 566c with a projection 569c, and a lumen 572c for receiving an engagement rod 547. However, the modular tip 590 further has a pair of drill guides 594 configured to align with openings in the implant, such as the first hole 173 and the second hole 174 of the implant 140. The modular tip 590 is not shown to have a stopper like the stoppers of the other modular tips shown, but those skilled in the art will understand that such a feature may be included. Those skilled in the art will further understand that the size and shape of the drill guides 594 may be adjusted to the size of a particular implant, the size of the threads, the shape of the implant, etc.

[0070] The use of modular tips allows insertion kits to include a single insert with multiple tips, rather than multiple inserts. Another advantage of modular tips is that they allow for adjustment and customization of specific procedures.

[0071] Multiple embodiments are disclosed herein. For example, Embodiment 1 is a method for manufacturing a composite intervertebral implant, comprising: selecting a metal alloy body having an upper surface and an opposite bottom surface; cutting off a portion of the upper surface of the metal alloy body; cutting off a portion of the bottom surface of the metal alloy body; joining a porous metal to the upper surface; joining a porous metal to the bottom surface to form a composite metal alloy block; and separating a composite intervertebral implant from the composite metal alloy block.

[0072] Embodiment 2 is a method for manufacturing a composite intervertebral implant, comprising: selecting a solid titanium body having an upper and a bottom; cutting off a portion of the upper part of the solid titanium body to form an upper cavity; cutting off a portion of the bottom part of the solid titanium body to form a bottom cavity; diffusion bonding porous titanium to the upper cavity; diffusion bonding porous titanium to the bottom cavity; forming a composite titanium block by diffusion bonding of porous titanium to the upper and bottom cavities; and separating the composite intervertebral implant from the composite titanium block.

[0073] Embodiment 3 is a method for manufacturing a composite intervertebral implant, comprising: selecting a solid titanium body having an upper surface, an opposite bottom surface, and side surfaces; joining porous titanium to the upper surface; joining porous titanium to the bottom surface; joining a solid titanium block perpendicularly to the side surfaces to form a composite titanium block; and separating the composite intervertebral implant from the composite titanium block.

[0074] Embodiment 4 is a method for manufacturing a composite intervertebral implant, comprising: selecting a solid titanium body having an upper surface and a lower surface; cutting off a portion of the upper surface of the solid titanium body; cutting off a portion of the lower surface of the solid titanium body; joining a metal to the upper surface; joining a porous metal to the lower surface to form a composite titanium body; and separating the composite intervertebral implant from the composite titanium body.

[0075] Embodiment 5 comprises a composite intervertebral implant system having a main body having a front and a rear surface on the opposite side, an upper portion and a bottom portion, with an intermediate portion extending through the main body from the front to the rear surface on the opposite side, the front being made of titanium alloy, the upper and bottom portions being made of porous titanium, and the intermediate portion being made of titanium alloy.

[0076] Embodiment 6 comprises the composite intervertebral implant system according to Embodiment 5, wherein the front and middle portions are formed from a single titanium alloy. Embodiment 7 comprises the composite intervertebral implant system according to Embodiment 5 or 6, wherein the porous titanium comprises sheets of porous titanium that are diffusion-bonded together to form a porous titanium. Embodiment 8 comprises the composite intervertebral implant system according to any one of Embodiments 5 to 7, wherein the upper portion is diffusion-bonded to the upper surface of the middle portion and the bottom portion is diffusion-bonded to the bottom surface of the middle portion.

[0077] Embodiment 9 is a composite intervertebral implant system comprising a main body having an anterior and an opposite posterior surface, an upper portion and a bottom portion, the middle portion extending from the front to the opposite posterior surface through the main body, the front surface being made of a solid metal alloy, the upper and bottom portions being made of a porous metal, the middle portion being made of a solid metal alloy, the front surface having at least one hole for receiving a bone screw, and the composite intervertebral implant system comprising at least one fixation mechanism for preventing retraction of the bone screw.

[0078] Embodiment 10 further comprises the composite interbody implant system according to Embodiment 9, wherein the front surface further has an axial channel proximal to at least one hole, and the fixation mechanism has a cylinder with an outwardly projecting tab, the cylinder being receivable into the axial channel, and the outwardly projecting tab extending at least partially into at least one hole.

[0079] Embodiment 11 comprises a composite interbody implant system according to Embodiment 10, wherein the outwardly projecting tab further has an angled surface such that when the bone screw is inserted into at least one hole, the bone screw can deviate the tab projecting outward from the fixation mechanism. Embodiment 12 comprises a composite interbody implant system according to Embodiment 10 or 11, wherein after the outwardly projecting tab is deviated by the bone screw, the outwardly projecting tab is biased and extends into at least one hole.

[0080] Embodiment 13 further comprises the composite interbody implant system according to Embodiment 9, wherein the front surface further has an axial channel proximal to at least one hole, and the fixation mechanism has a stopper having at least one outwardly projecting arm, the stopper being receivable into the axial channel and rotatable within the axial channel between a fixed configuration and an open configuration. Embodiment 14 comprises the composite interbody implant system according to any one of Embodiments 9 to 13, wherein the body is cut from a composite metal alloy block formed by the method of Embodiment 1.

[0081] Embodiment 15 comprises a composite interbody implant system according to any one of Embodiments 9 to 14, wherein the body is cut from a composite titanium block formed by the method described in any one of Embodiments 2 to 4. Embodiment 16 comprises a composite interbody implant system according to any one of Embodiments 9 to 15, wherein at least one hole has at least partially threaded holes. Embodiment 17 comprises a composite interbody implant system according to Embodiment 16, wherein the threads of at least one hole are configured to engage with the corresponding threads of a bone screw. Embodiment 18 comprises a composite interbody implant system according to Embodiment 16 or 17, wherein the bone screw has a head having at least partially threaded holes. Embodiment 19 comprises a composite interbody implant system according to Embodiment 17 or 18, wherein a gap is provided between the threads of at least one hole and the corresponding threads of a bone screw.

[0082] Embodiment 20 comprises a main body having a front and a rear surface on the opposite side, an upper portion and a bottom portion, with an intermediate portion extending through the main body from the front to the rear surface on the opposite side, separating the upper portion and the bottom portion, the front surface being made of a solid metal alloy, the upper portion and the bottom portion being made of a porous metal, the intermediate portion being made of a solid metal alloy, the front surface having a first hole for receiving a first bone screw, and a first inwardly extending channel provided proximal to the first hole for receiving a first fixing mechanism, the front surface having a second hole for receiving a second bone screw, and provided proximal to the second hole The composite intervertebral implant system comprises a first fixation mechanism having a second inwardly extending channel for receiving a second fixation mechanism, the first fixation mechanism having a cylinder receivable into the first inwardly extending channel and having an inner end and an outer end, and a first tab protruding outward from the outer end of the cylinder and at least partially protruding into the first hole, and the second fixation mechanism having a cylinder receivable into the second inwardly extending channel, and a second tab protruding outward from the cylinder and at least partially protruding into the second hole.

[0083] Embodiment 21 comprises the composite interbody implant system according to Embodiment 20, wherein the first tab and the second tab are biased to protrude at least partially into the first and second holes. Embodiment 22 comprises the composite interbody implant system according to Embodiment 21, wherein the first tab and the second tab have angled surfaces. Embodiment 23 comprises the composite interbody implant system according to Embodiment 22, wherein the outer end of the cylinder is cut out so that the tab of the first fixation mechanism can be pushed out of the first hole by the pressure of the inwardly moving first bone anchor, and the tab of the second fixation mechanism can be pushed out of the second hole by the pressure of the inwardly moving second bone anchor. Embodiment 24 comprises the composite interbody implant system according to Embodiment 23, wherein the tab of the first fixation mechanism and the tab of the second fixation mechanism are biased to protrude at least partially into the first and second holes, respectively.

[0084] Embodiment 25 is a composite intervertebral implant system comprising a main body having a front surface and a rear surface on the opposite side, an upper portion and a bottom portion, an intermediate portion penetrating the main body and extending from the front surface to the rear surface on the opposite side, separating the upper portion and the bottom portion, the front surface being formed of a solid metal alloy, the upper portion and the bottom portion being formed of a porous metal, the intermediate portion being formed of a solid metal alloy, the front surface having a first hole for receiving a first bone anchor and a second hole for receiving a second bone anchor, and the composite intervertebral implant system comprising a fixing mechanism for preventing the retraction of the first bone anchor and the second bone anchor, respectively, from the first hole and the second hole.

[0085] Embodiment 26 further comprises the composite intervertebral implant system according to Embodiment 25, wherein the front surface has a molded cavity for receiving a fixing mechanism, which is provided between a first hole and a second hole, and the fixing mechanism has a rotatable stopper positioned in the molded cavity between the first hole and the second hole, the rotatable stopper having a first open position into which a bone anchor can be inserted and a second closed position into which a bone anchor cannot be inserted. Embodiment 27 comprises the composite intervertebral implant system according to Embodiment 26, wherein the rotatable stopper extends into the first and second holes in the second closed position, but does not extend into the first and second holes in the first open position.

[0086] Embodiment 28 comprises the composite interbody implant system according to Embodiment 27, wherein the main body has a vertical opening, the fixing mechanism further has a vertical pin, and the rotating stopper has an opening for receiving the vertical pin for holding the rotating stopper in a predetermined position on the main body. Embodiment 29 comprises the composite interbody implant system according to any one of Embodiments 26 to 28, wherein the rotating stopper has a first outwardly extending arm and a second outwardly extending arm, and the molded cavity has a first slot for the first outwardly extending arm to rotate internally and a second slot for the second outwardly extending arm to rotate internally.

[0087] Embodiment 30 comprises a composite interbody implant system according to Embodiment 29, wherein a second outwardly extending arm is rotatable from about 0 to about 45 degrees by a first slot, and the first outwardly extending arm is rotatable from about 180 to about 225 degrees by a second slot. Embodiment 31 comprises a composite interbody implant system according to any one of Embodiments 26 to 30, wherein the molded cavity further has at least one further notch for receiving an insert. Embodiment 32 comprises a composite interbody implant system according to any one of Embodiments 26 to 31, wherein the rotatable stopper further has threads for engaging with an insert.

[0088] Embodiment 33 comprises a composite intervertebral implant system according to any one of Embodiments 20 to 32, wherein the main body is cut from a composite metal alloy block formed by the method of Embodiment 1. Embodiment 34 comprises a composite intervertebral implant system according to any one of Embodiments 20 to 32, wherein the main body is cut from a composite titanium block formed by the method of Embodiment 2 or 3. Embodiment 35 comprises a composite intervertebral implant system according to any one of Embodiments 20 to 32, wherein the main body is cut from a composite titanium body formed by the method of Embodiment 4.

[0089] Although the method and device described herein are specifically described in relation to their use in spinal implants, other applications are possible and are considered herein. The various embodiments described above, including elements of the various embodiments described above, can be combined to provide further embodiments. Various parts and components of the apparatus within the scope of this disclosure, including structural components, can be formed by one or more various suitable manufacturing processes known to those skilled in the art. Similarly, various parts and components of the apparatus within the scope of this disclosure can be formed from suitable materials known to those skilled in the art.

[0090] The above description illustrates various features, functions, methods, and other aspects of this disclosure. The timelines and further development examples may change how the various aspects are carried out. The scope of protection defined by the claims is not intended to be limited to any particular size, shape, feature, or other aspect of the disclosed embodiments. The claimed invention may be carried out or embodied in other forms, while still remaining within the scope of the concept disclosed herein. Further equivalents of the elements of the claims are included below, which may be made without departing from the scope of the concept adequately protected by the claims.

[0091] Related applications This application claims priority to U.S. Provisional Application No. 63 / 082782, filed on 24 September 2020, the entirety of which is incorporated herein by reference.

Claims

1. A body having a front surface and an opposite rear surface having at least one hole for receiving a bone screw, an upper portion and a bottom portion provided between the front surface and the rear surface of the body, and at least one fixing mechanism for preventing the bone screw from retracting, wherein the intermediate portion extends from the front surface to the opposite rear surface through the central portion of the body, The front surface is made of titanium alloy, the upper and bottom portions are made of porous titanium, and the intermediate portion is made of titanium alloy. The aforementioned front surface further has a channel provided adjacent to the at least one hole, A composite intervertebral implant system comprising a fixing mechanism having a cylinder with an outwardly projecting tab, the cylinder being receivable into the channel, and the outwardly projecting tab extending at least partially into the at least one orifice when the cylinder is receivable into the channel.

2. The composite intervertebral implant system according to claim 1, wherein the front and intermediate portions are formed from a single titanium alloy.

3. The composite intervertebral implant system according to claim 1 or 2, wherein the porous titanium includes sheets of porous titanium that are diffusion-bonded together to form porous titanium.

4. The composite intervertebral implant system according to any one of claims 1 to 3, wherein the upper portion is diffusely bonded to the upper surface of the intermediate portion, and the bottom portion is diffusely bonded to the bottom surface of the intermediate portion.

5. A composite intervertebral implant system, It comprises a main body having a front and a rear on the opposite side, and an upper portion and a bottom portion provided between the front and rear surfaces of the main body, with the intermediate portion extending from the front to the rear on the opposite side, passing through the central portion of the main body. The front surface is formed of a solid metal alloy, the upper and bottom portions are formed of a porous metal, and the intermediate portion is formed of a solid metal alloy. The aforementioned front surface has at least one hole for receiving a bone screw, The aforementioned composite intervertebral implant system includes at least one fixation mechanism to prevent the bone screw from retracting. The aforementioned front surface further has an axial channel provided adjacent to the at least one hole, A composite intervertebral implant system comprising a fixing mechanism having a cylinder with an outwardly projecting tab, the cylinder being receivable into the axial channel, and the outwardly projecting tab extending at least partially into the at least one orifice when the cylinder is receivable into the axial channel.

6. The composite intervertebral implant system according to claim 5, wherein the tab protruding outward from the fixing mechanism further has an angled surface such that the bone screw can deflect the tab protruding outward when the bone screw is inserted into the at least one hole.

7. The composite intervertebral implant system according to claim 5 or 6, wherein the outwardly projecting tab is biased by the bone screw, and then the outwardly projecting tab is biased to extend into the at least one hole.

8. The aforementioned front surface further has an axial channel provided adjacent to the at least one hole, The composite intervertebral implant system according to claim 5, wherein the fixing mechanism has a blocking body having at least one outwardly projecting arm, the blocking body being receivable into the axial channel and rotatable within the axial channel between a fixed configuration and an open configuration.

9. The composite intervertebral implant system according to any one of claims 5 to 8, wherein the at least one hole has at least partially threaded holes.

10. The composite intervertebral implant system according to claim 9, wherein the threads of at least one hole are configured to engage with the corresponding threads of the bone screw.

11. The composite intervertebral implant system according to claim 9 or 10, wherein the bone screw has a head having at least partially threaded holes.

12. A composite intervertebral implant system according to claim 10 or 11, wherein a gap is provided between the threads of at least one hole and the corresponding threads of the bone screw.

13. It comprises a main body having a front and a rear on the opposite side, and an upper portion and a bottom portion provided between the front and rear surfaces of the main body, with the intermediate portion penetrating the central portion of the main body and extending from the front to the rear on the opposite side, separating the upper portion and the bottom portion. The front surface is formed of a solid metal alloy, the upper and bottom portions are formed of a porous metal, and the intermediate portion is formed of a solid metal alloy. The front surface has a first hole for receiving a first bone screw, and a first inwardly extending channel provided adjacent to the first hole on the front surface for receiving a first fixing mechanism. The front surface has a second hole for receiving a second bone screw, and a second inwardly extending channel provided adjacent to the second hole on the front surface for receiving a second fixing mechanism. The first fixing mechanism comprises a cylinder that is receivable into a first inwardly extending channel and has an inner end and an outer end, and a first tab that protrudes outward from the outer end of the cylinder and at least partially protrudes into the first hole when the cylinder is receivable into the first inwardly extending channel, A composite intervertebral implant system comprising: a second fixation mechanism having a cylinder receivable into a second inwardly extending channel; and a second tab protruding outward from the cylinder and at least partially protruding into the second opening when the cylinder is received into the second inwardly extending channel.

14. The composite intervertebral implant system according to claim 13, wherein the first tab and the second tab are biased to protrude at least partially into the first and second bores.

15. The composite intervertebral implant system according to claim 14, wherein the first tab and the second tab have angled surfaces.

16. The composite intervertebral implant system according to claim 15, wherein the outer end of the cylinder is cut out so that the pressure of the inwardly moving first bone anchor can push out the first tab of the first fixation mechanism from the first hole, and the pressure of the inwardly moving second bone anchor can push out the second tab of the second fixation mechanism from the second hole.

17. The composite intervertebral implant system according to claim 16, wherein the first tab of the first fixation mechanism and the second tab of the second fixation mechanism are biased to protrude at least partially into the first and second holes, respectively.

18. A method for manufacturing a composite intervertebral implant system according to any one of claims 5 to 12, The aforementioned main body, Select a metal alloy body having a top surface and a bottom surface on the opposite side. A portion of the upper surface of the aforementioned metal alloy body is cut off, A portion of the bottom surface of the aforementioned metal alloy body is cut off, A porous metal is bonded to the upper surface, A composite metal alloy block is formed by bonding a porous metal to the bottom surface. The composite intervertebral implant is separated from the aforementioned composite metal alloy block. A method of cutting from a composite metal alloy block formed by a certain method.

19. A method for manufacturing a composite intervertebral implant system according to any one of claims 5 to 12, The aforementioned main body, Select a solid titanium body having an upper and a bottom, A portion of the upper part of the solid titanium body is cut off to form an upper cavity, A portion of the bottom of the solid titanium body is cut off to form a bottom cavity, Porous titanium is diffuse-bonded to the aforementioned upper cavity. A composite titanium block is formed by diffusion bonding porous titanium to the bottom cavity, and by diffusion bonding of porous titanium to the upper cavity and the bottom cavity. A method for separating a composite intervertebral implant from the composite titanium block (a), Select a solid titanium body having a top surface, an opposite bottom surface, and sides. Porous titanium is bonded to the upper surface, Porous titanium is bonded to the bottom surface, A composite titanium block is formed by joining solid titanium blocks perpendicularly to the aforementioned side surfaces. A method for separating a composite intervertebral implant from the composite titanium block (b), and Select a solid titanium body having a top and bottom surface, A portion of the upper surface of the aforementioned solid titanium body is cut off, A portion of the bottom surface of the aforementioned solid titanium body is cut off, A metal is joined to the upper surface, A porous metal is bonded to the bottom surface to form a composite titanium body. (c) A method for separating the composite intervertebral implant from the composite titanium body. A method of cutting from a composite titanium block formed by any one of the methods described herein.

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