Movement maintenance system and apparatus

Abstract

A system, apparatus, and method for maintaining movement in an intervertebral disc are provided. Modular intervertebral disc implant segments can be constructed from a relatively rigid material configured to exhibit the properties of a compressible solid, such as an elastomer. The material may be configured to include one or more structural voids, including a leaf spring design, thereby enhancing the compressive capacity of the modular intervertebral disc implant segments. As a result, the entire intervertebral disc constructed from multiple modular intervertebral disc implant segments becomes compressible in response to the movement of the implant recipient.

Description

Technical Field

[0001] The present disclosure relates to medical motion retention systems, devices, and methods, including intervertebral disc nucleus replacement systems and devices such as implantable prostheses for intervertebral disc repair.

[0002] [Related Application] This application claims priority under 35 U.S.C. § 119(e) to Provisional Patent Application No. 63 / 521,495, filed on June 16, 2023, the entire content of which is incorporated herein by reference.

Background Art

[0003] The spinal motion unit is a spinal anatomical unit that includes two vertebral bodies, the intervertebral disc intervening therebetween, and the attached ligaments, muscles, and facet joints. The intervertebral disc consists of an end plate located at the upper and lower ends of the vertebral body, a soft inner core called the nucleus pulposus, and an annulus fibrosus that circumferentially surrounds the nucleus pulposus. In a normal intervertebral disc, the nucleus pulposus buffers the load applied thereto and protects the other components of the spinal motion unit. The normal intervertebral disc nucleus pulposus responds to compressive forces and transmits these forces to the vertebral end plates and the annulus fibrosus. The annulus fibrosus is composed of collagen fibers and a small amount of elastic fibers, both of which are excellent in resistance to tensile forces. However, the annulus fibrosus alone has low resistance to compressive shear forces and loses the ability to maintain the physiological intervertebral distance without a functioning nucleus pulposus. As a result, the nerve root exiting the intervertebral foramen is compressed and stimulated, causing low back pain.

[0004] As we age, intervertebral discs often undergo natural degenerative changes. Intervertebral disc degeneration is one of the most common diseases in our population that causes pain and dysfunction. Disc degeneration occurs when the nucleus pulposus becomes dehydrated. When the nucleus pulposus becomes dehydrated, its cushioning function deteriorates. Because the dehydrated nucleus pulposus can no longer support the load, the load shifts to the annulus fibrosus and facet joints. The annulus fibrosus and facet joints cannot withstand the increased compressive and torsional loads and gradually deteriorate. When the annulus fibrosus and facet joints degenerate, many secondary changes occur, including narrowing of the intervertebral space, osteophyte formation, fragmentation of the annulus fibrosus, rupture and degeneration of the cartilage endplate, and degeneration of the facet joint cartilage. The annulus fibrosus and facet joints lose structural stability, and subtle pathological movements occur between the vertebral bodies.

[0005] Decomposition products of the intervertebral discs (including visible fragments, microparticles, and harmful biochemicals) accumulate. These particles and fragments can cause nerve compression and sciatica, while harmful biochemicals irritate sensitive nerve endings within and around the intervertebral disc, leading to lower back pain. Affected patients may experience muscle spasms, decreased flexibility in the lower back, and pain when attempting normal trunk movements.

[0006] Disc degeneration is irreversible. In some cases, the body may eventually stiffen the joints of the kinetic segments, thereby re-stabilizing the disc. Even when re-stabilization occurs, the process takes many years, and patients often continue to experience pain accompanied by functional impairment. Generally, if pain persists for more than three months, patients tend to seek surgical treatment for the pain.

[0007] The following methods have been proposed to stabilize the spinal motor unit. 1) A method of heating the annulus fibrosus region to destroy nerve endings and strengthen the annulus fibrosus. 2) A method of placing a rigid or semi-rigid support member laterally to a motor unit or within the intervertebral disc space. 3) A method of removing the entire intervertebral disc and replacing it with a movable prosthesis, generally made of rigid plastic, or a method of permanently fixing the vertebral body adjacent to the affected intervertebral disc.

[0008] Until now, spinal fusion has been the most commonly used surgical treatment for lower back pain caused by intervertebral disc degeneration. While this treatment is often effective in relieving lower back pain, it completely eliminates intervertebral disc movement in the fixed spinal unit.

[0009] Loss of mobility in the affected spinal segment inevitably limits the overall mobility of the patient's spine. Furthermore, spinal fusion places excessive stress on the intervertebral discs adjacent to the fused segment, and these adjacent segments often cause premature degeneration of the adjacent discs as they try to compensate for the lack of mobility in the fused segment.

[0010] Recent developments have focused on treatments that can partially or completely preserve the mobility of the affected spinal segment. Total disc replacement has been proposed as one method to stabilize the spinal motor unit while avoiding the drawbacks of spinal fusion. Total disc replacement is a highly invasive and technically advanced surgery that accesses the disc from an anterior approach and involves cutting the anterior longitudinal ligament, removing the cartilaginous endplate located between the vertebral body and the disc, and completely removing most of the lateral annulus fibrosus and the medial nucleus pulposus. A total disc prosthesis is then placed in the removed disc cavity. Many of the artificial disc replacements currently available feature a core made of a rigid plastic material, such as ultra-high molecular weight polyethylene (UHMWPE), interposed between two metal plates that are fixed or bonded to the vertebral endplate.

[0011] A historical overview of the initial development and design of artificial intervertebral discs is described in "Ray, The Artificial Disc: Introduction, History and Socioeconomics," Chapter 21, "Clinical Effectiveness and Outcomes in the Diagnosis of Low Back Pain," Raven Press (1992), pp. 205-225.

[0012] These artificial disc replacements have several drawbacks. For example, because they are relatively large, their insertion requires significant surgical exposure. The greater the surgical exposure, the higher the risk of infection, bleeding, and even complications. Also, a large portion of the annulus fibrosus must be removed to implant the prosthesis, resulting in reduced stability of the motor segment, at least until healing around the artificial disc is complete. Furthermore, because these devices are made of rigid materials, they can cause serious damage if they displace from the intervertebral disc space and come into contact with local nerve or vascular tissue. In addition, rigid artificial disc replacements do not adequately replicate the biomechanical behavior of a normal intervertebral disc.

[0013] As an alternative to total disc replacement, nucleus pulposus replacement bodies, which are inert, non-rigid, and non-biological replacements similar to artificial disc prostheses, have been proposed. Some conventional nucleus pulposus replacement bodies utilize the water-absorbing properties of hydrogels to expand in the body, thereby more completely filling the removed nuclear cavity. However, there is a trade-off: the greater the hydrogel expansion, the less structural support the implant can provide. For this reason, many hydrogel-type nucleus pulposus replacement bodies use a jacket or fabric shell to restrain the hydrogel material. Without these restraints, the hydrogel's slippery nature makes it prone to movement or displacement. On the other hand, jackets and fabric shells are susceptible to wear and tear with long-term use, which may reduce their ability to restrain the hydrogel. As a result, there is a risk of the hydrogel dislodgeing.

[0014] Another undesirable technique in nucleus pulposus replacement involves implanting a container, such as a balloon, into the nucleus pulposus and filling it with biocompatible material, which is then cured in situ. This method generates a large amount of heat due to the exothermic chemical curing reaction, potentially damaging surrounding tissues. Furthermore, leakage of the material into the intervertebral disc cavity or surrounding tissues can lead to undesirable complications. Additionally, polymers that cure in situ often contain highly toxic monomers, and leakage of these monomers into the patient's tissues or bloodstream can cause serious adverse effects. Many of these monomers are known to be carcinogenic.

[0015] Another technique for nucleus pulposus replacement, as described in U.S. Patents 5,702,454 and 5,755,797, involves implanting numerous individual support members, such as beads, one by one until the intervertebral disc cavity is filled. Because these beads are small, they can potentially dislodge from the intervertebral disc cavity. Furthermore, from a mechanical standpoint, the positional relationships and interactions of the multiple beads or support members can change during and after implantation, making it difficult to obtain consistent and reproducible results.

[0016] Recent attempts at nucleus pulposus prostheses have included, for example, those described in U.S. Patent No. 8,100,977, which use multiple elastomer components to create a structure composed entirely of elastomer material. However, friction at the interfaces between polymers makes implantation extremely difficult for surgeons, often resulting in the inability to securely engage the module. Furthermore, elastomer materials shrink over time, losing some of their tensile strength. This undesirable behavior specific to elastomers is called compression set. In addition, other prior art has proposed a configuration that combines an elastomer outer shell with a rigid inner shell to enable sliding and fixing of the module, but this has the problem of biomechanical instability due to mismatch in elastic modulus. Moreover, in configurations combining a flexible inner shell (hydrogel) with a rigid outer shell, there is a risk of separation and dislocation.

[0017] Therefore, there is a need for a nucleus pulposus prosthesis that can be inserted by minimally invasive surgery and that mimics the properties of a natural intervertebral disc. This disclosure provides a system, apparatus, and method to address the shortcomings of the prior art and other challenges described above. [Overview of the project]

[0018] This disclosure relates to medical motion retention systems, devices, and methods. Embodiments include implantable spinal prostheses for repairing intervertebral discs. In some embodiments, such implantable prostheses include interconnected modular intervertebral disc nucleus pulposus implants.

[0019] In one embodiment, one or more modular intervertebral disc implant segments include a relatively rigid material that behaves similarly to, or substantially to, a solid material (e.g., an elastomer) that exhibits at least compressibility and elasticity. For example, the material includes one or more structural voids that can be occupied by air, liquid, gel, foam, or a more compressible material.

[0020] In a particular embodiment, at least one of the modular intervertebral disc implant segments comprises a solid material such as a biocompatible polymer or metal, which comprises one or more structural voids, allowing the solid material to be compressed into each structural void when pressure is applied. The solid material exhibits elastic recovery properties that, upon recovery from compression, allow each modular intervertebral disc implant segment to partially or completely return to the original shape of the structural void. In this way, the modular intervertebral disc implant segment mimics or simulates the natural elastic properties of a healthy nucleus pulposus and functions as an implantable prosthesis for repairing a damaged intervertebral disc.

[0021] One or more modular intervertebral disc implant segments can be used as implantable prostheses to repair damaged intervertebral discs. In one embodiment, multiple modular intervertebral disc implant segments are assembled as a single compressible and elastic replacement for the nucleus pulposus extracted within the annulus fibrosus. The modular intervertebral disc implant segments are inserted through an access opening formed in the intervertebral disc, such as by passing through the annulus fibrosus. Each modular intervertebral disc implant segment is sequentially inserted into the intervertebral disc cavity formed by the extracted nucleus pulposus, and the second through last inserted modular intervertebral disc implant segments are connected to the adjacent modular intervertebral disc implant segment inserted immediately before them.

[0022] With this configuration, the excised nucleus pulposus is ultimately replaced by appropriately configured modular intervertebral disc implant segments utilizing at least one structural void, resulting in a one-piece prosthesis with compressive and elastic properties similar to those of a healthy nucleus pulposus.

[0023] Thus, the embodiments described herein include representative examples of connectable (and in some cases engagable) modular intervertebral disc implant segments that are formed in situ and become nucleus pulposus mimetic devices that exhibit elastomeric-like properties substantially equivalent to a healthy nucleus pulposus, and that simulate the restoration of an intervertebral disc to its pre-injury state.

[0024] One embodiment relates to a modular connectable segment that is assembled in situ with one or more other modular connectable segments to ultimately provide an implantable intervertebral disc prosthesis. The modular connectable segment is composed of a generally non-elastic material that is compressible into one or more integrated spaces or voids. In certain embodiments, a modular intervertebral disc implant segment is provided that includes one or more structural gaps, openings, slits, or other structural voids to facilitate compression of the implant segment in response to an external force. The implant segment is configured to return to its original geometric shape in response to a decrease in the external force.

[0025] According to one embodiment, an intervertebral disc nucleus replacement device is provided that includes a plurality of modular intervertebral disc implant segments. At least one implant segment includes one or more structural voids that facilitate compression of the implant segment in response to an external force, and is configured to return to its original geometric shape in response to a decrease in the external force. Each implant segment is provided with a connection mechanism that facilitates connection to at least one other implant segment, and the intervertebral disc nucleus replacement device has an integrated structure composed of the connected implant segments.

[0026] In one embodiment of such an intervertebral disc nucleus replacement device, at least one structural void is configured as a leaf spring having a gap with one or more open ends.

[0027] In another embodiment, at least one structural void is configured as a leaf spring having one or more sealed internal spaces.

[0028] In such an embodiment of the intervertebral disc nucleus replacement device, each modular intervertebral disc implant segment may be composed of polyetheretherketone (PEEK). In still other embodiments, the modular intervertebral disc implant segment may be composed of a titanium alloy.

[0029] Such an intervertebral disc nucleus replacement device may further include an implant segment connection mechanism that can be coupled to the implant segment connection mechanism of at least one adjacent modular intervertebral disc implant segment. In one embodiment, the implant segment connection mechanism includes both a tongue-like element and a groove, and the groove is configured to enable a slip fit connection by receiving the tongue-like element of an adjacent modular intervertebral disc implant segment. In another embodiment, the implant segment connection mechanism includes either a tongue-like element or a groove, and a slip fit connection is enabled by the tongue-like element or groove provided in one modular intervertebral disc implant segment engaging with the corresponding tongue-like element or groove of an adjacent modular intervertebral disc implant segment.

[0030] The intervertebral disc nucleus replacement device may include modular intervertebral disc implant segments each having a tool connection mechanism that can be detachably connected to an installation tool.

[0031] In other embodiments of such an intervertebral disc nucleus replacement device, the structural voids are symmetrically arranged within at least one modular intervertebral disc implant segment. In other embodiments, the structural voids are asymmetrically arranged within at least one modular intervertebral disc implant segment. In one embodiment, the structural voids include an upper group of structural voids and a lower group of structural voids separated by a relatively less compressible central portion.

[0032] Another embodiment of such an intervertebral disc nucleus replacement device may further include a terminal modular intervertebral disc implant segment having a different arrangement of structural voids from other implant segments.

[0033] Another embodiment relates to a method for implanting a disc prosthesis in a patient. The method includes using a plurality of modular disc implant segments made of a material configured to be compressible in response to an external force and to return to its original geometric shape in response to a decrease in the external force. The method includes the steps of implanting a first modular disc implant segment and implanting a second modular disc implant segment, connecting it to the first modular disc implant segment via connecting mechanisms provided on each segment. The method further includes the step of forming an integrated disc prosthesis in the patient's body by implanting a final modular disc implant segment.

[0034] In other embodiments of this method, the process may further include the step of implanting one or more additional modular intervertebral disc implant segments between the first modular intervertebral disc implant segment and the last modular intervertebral disc implant segment via the respective connecting mechanisms of each modular intervertebral disc implant segment.

[0035] In other embodiments, each modular intervertebral disc implant segment is composed of polyetheretherketone (PEEK).

[0036] Another embodiment of such a method may further include the step of connecting an insertion tool to a connecting receptacle on a second modular intervertebral disc implant segment to facilitate insertion into the intervertebral disc space within the annulus fibrosus, and then removing the insertion tool from the connecting receptacle after the second modular intervertebral disc implant segment has been connected to the first modular intervertebral disc implant segment via its respective connecting mechanism.

[0037] In another embodiment, an intervertebral disc nucleus pulposus replacement implant is provided, which has a leaf spring configuration that provides the compressibility necessary to mimic the original nucleus pulposus in order to allow movement between adjacent vertebral bodies.

[0038] In other embodiments of intervertebral disc nucleus pulposus replacement implants, the spring plate elements in the implant's leaf spring configuration are retained connected to the implant body to form an open channel, while providing compressibility in flexion, extension, and lateral flexion of the vertebral movement segment via a series of arched spring structures.

[0039] In one embodiment, the leaf spring configuration includes a combination of open and closed leaf spring elements configured to optimize the flexibility of the implant in all vertebral movements.

[0040] In such embodiments of intervertebral disc nucleus pulposus replacement implants, materials having hardness or compressive modulus similar to bone may be used.

[0041] In another embodiment of such a disc nucleus pulposus replacement implant, the implant is composed of two or more modules, each of which can be individually inserted through a pathway within the annulus fibrosus.

[0042] In a more specific embodiment, one or more movable leaf springs are provided in a non-elastomer material, and these movable leaf springs are connected to and separated from the implant body via open channels, thereby making the entire implant compressible. In another embodiment, the compressibility of the leaf spring configuration is improved by the anterior open channel terminating in a substantially circular space that expands towards the rear. In yet another embodiment, the compressibility of the leaf spring configuration is improved by the posterior open channel terminating in a substantially circular space that expands towards the front.

[0043] In another embodiment of the intervertebral disc nucleus pulposus replacement implant using a movable leaf spring, each module has a Z-shaped channel in which the first open end of the upper channel faces posteriorly and the second open end of the lower channel faces anteriorly. In yet another embodiment, each module has a Z-shaped channel in which the first open end of the lower channel faces posteriorly and the second open end of the upper channel faces anteriorly.

[0044] In another embodiment of a disc nucleus pulposus replacement implant using movable leaf springs, each of the multiple modules connected to form the disc nucleus pulposus replacement implant is provided with two or more leaf springs.

[0045] In yet another embodiment of a disc nucleus pulposus replacement implant using a movable leaf spring, the material of the disc nucleus pulposus replacement implant is polyetheretherketone (PEEK). In another embodiment, the material includes a thermoplastic resin, and in yet another embodiment, it includes a composite material of an elastomer and a thermoplastic resin. In yet another embodiment, the material includes an elastomer, and in yet another embodiment, the material includes a metal. In yet another embodiment, the material includes a composite material of a metal and a polymer (elastomer or thermoplastic resin). These implants are applicable to posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), and insertion via a lateral approach. In yet another embodiment, the modules constituting the disc nucleus pulposus replacement implant are inserted using sequential expanders and traction devices.

[0046] In yet another embodiment, a device is provided for forming a space between two adjacent vertebral bodies. The device consists of several coaxially arranged members of progressively different sizes to expand the annulus fibrosus and apply force to the vertebral endplates to increase the separation amount. The final member of the member row provides the desired endplate separation amount and has an internal diameter dimension for passing the device and intervertebral implant module.

[0047] In yet another embodiment, an intervertebral disc nucleus pulposus replacement device is provided having one or more structural voids within a substantially inelastic component. These structural voids facilitate the compressibility of the component when it is placed within the intervertebral disc as a replacement for the original nucleus pulposus.

[0048] This summary provides a simplified and selective overview of some of the representative concepts and embodiments described or taught to those skilled in the art in this specification. This summary is not intended to represent all embodiments, scopes, or claims supported by this specification, nor is it intended to identify or limit the essential features of the claimed subject matter. [Brief explanation of the drawing]

[0049] [Figure 1] A first representative embodiment of a modular intervertebral disc implant system is shown, configured to utilize and interconnect multiple modular intervertebral disc implant segments to form an intervertebral disc prosthesis. [Figure 2A] A representative embodiment of a modular intervertebral disc implant segment is shown, which can form part of an intervertebral disc prosthesis containing multiple modular intervertebral disc implant segments. [Figure 2B] The images show typical isometric projections of various faces of modular intervertebral disc implant segments. [Figure 2C] Multiple cross-sectional views of a modular intervertebral disc implant segment 200 in isometric projection are shown. [Figure 2D] The image shows multiple cross-sectional views of the opposite side of the modular intervertebral disc implant segment 200 in isometric projection. [Figure 2E] This shows a typical method for connecting two (or more) modular intervertebral disc implant segments. [Figure 2F] This shows an example of a disc nucleus prosthesis formed by connecting multiple modular intervertebral disc implant segments. [Figure 2G] Several aspects of a typical intervertebral disc nucleus prosthesis 210 are shown. [Figure 2H] This diagram shows the terminal and internal modular intervertebral disc implant segments of a typical five-part intervertebral disc nucleus prosthesis. [Figure 2I]Another embodiment of a disc nucleus prosthesis formed by multiple interconnected modular disc implant segments is shown. [Figure 2J] This shows typical terminal modular intervertebral disc implant segments that can be used as end caps for intervertebral disc nucleus prostheses. [Figure 3A] Another embodiment of a disc nucleus prosthesis utilizing a leaf spring design in accordance with the principles of this disclosure is shown. [Figure 3B] Another embodiment of a disc nucleus prosthesis utilizing a leaf spring design in accordance with the principles of this disclosure is shown. [Figure 3C] Another embodiment of a disc nucleus prosthesis utilizing a leaf spring design in accordance with the principles of this disclosure is shown. [Figure 3D] Another embodiment of a disc nucleus prosthesis utilizing a leaf spring design in accordance with the principles of this disclosure is shown. [Figure 3E] Another embodiment of a disc nucleus prosthesis utilizing a leaf spring design in accordance with the principles of this disclosure is shown. [Figure 4] This describes a typical method for implanting modular intervertebral disc implant segments into the annulus fibrosus. [Figure 5] This document illustrates a typical procedure for a surgeon to implant an integrated disc prosthesis by performing the instructions described herein. [Modes for carrying out the invention]

[0050] In the following descriptions of various embodiments, reference will be made to the accompanying drawings, which constitute part of this specification. The drawings illustrate representative embodiments that enable the features described herein. Other embodiments can be used without departing from the scope of this disclosure, even with structural and operational modifications.

[0051] Generally, systems, apparatus, and methods for providing implantable prostheses for repairing damaged intervertebral discs are disclosed. These include, but are not limited to, interconnected modular intervertebral disc nucleus implant devices. Embodiments include modular intervertebral disc implant segments comprising one or more internal portions having higher compressibility than the surrounding structure. This facilitates the compression / deformation of the surrounding structure into one or more internal portions having higher compressibility. In one embodiment, at least one of the higher compressibility portions is a structural void filled with air or fluid surrounding the surrounding structure when surgically placed in the human body. Such modular intervertebral disc implant segments can be sequentially inserted into the intervertebral disc space and interconnected to form a single structure capable of functioning as a replacement for the nucleus pulposus in a damaged intervertebral disc.

[0052] Embodiments of medical devices include intervertebral disc nucleus pulposus replacement devices having one or more structural cavities within substantially non-elastomer components. These structural cavities facilitate the compressibility of the substantially non-elastomer components near the one or more structural cavities when placed within the intervertebral disc and positioned as a replacement for the original nucleus pulposus. For example, in some embodiments, a leaf spring structure is used, which is compressible by a gap formed between the leaf spring and the other parts of the intervertebral disc implant segment.

[0053] In one embodiment, a connectable or interconnectable modular intervertebral disc nucleus implant system and apparatus are provided. Here, the connectable / interconnectable modular implant is made of a material that is compressible yet can withstand rigorous operation in the body. One such material is polyetheretherketone (PEEK). The PEEK material used in the embodiments described herein may exhibit heat resistance, chemical resistance, mechanical strength, abrasion resistance, and biocompatibility. These materials may also exhibit a compressive modulus equivalent to or similar to that of human bone.

[0054] As described above, one embodiment includes providing one or more structural voids in at least some or all of a plurality of modular intervertebral disc implant segments. This allows each modular intervertebral disc implant segment to be compressed within the structural void. For example, Figure 1 shows a typical first modular intervertebral disc implant segment 100A that is interconnectable or connectable to at least one adjacent modular intervertebral disc implant segment 100n. Here, any number of connectable implant segments 100A to 100n can be implemented.

[0055] In the example shown in Figure 1, at least one structural void 104A is included to facilitate the compression of modular intervertebral disc implant segments, such as PEEK modular intervertebral disc implant segments. Any number or configuration of structural voids can be implemented to obtain appropriate compressibility and elastic recovery, as exemplified by representative structural voids 104A, 104B, 104C, 104D and / or 104n, etc. Representative structural voids 104A, 104B, 104C, 104D, and 104n are merely illustrative examples, and those skilled in the art will readily understand other arrangements and embodiments from the teachings herein.

[0056] When multiple adjacent modular intervertebral disc implant segments 100A to 100n are connected to form a single compressible structure 102, the structure 102 functions as a movement-retaining device for replacing the extracted and damaged nucleus pulposus. In some embodiments, one or more end modular intervertebral disc implant segments 106A, 106B may have the same or different internal configuration as the intermediate modular intervertebral disc implant segments. As shown in Figure 1, the total number of modular intervertebral disc implant segments used is arbitrary (with or without end segments). In some embodiments, the number of modular intervertebral disc implant segments can range from a minimum of two to the maximum number that can be reasonably inserted and connected within a given intervertebral disc cavity, but from the viewpoint of practicality in sizing, a total of about 3 to 5 implant segments may be preferable.

[0057] The embodiments may provide any number of structural voids 104A to 104n (collectively referred to as structural voids 104) to provide the desired compressibility and required durability / safety profile. In one embodiment, a single structural void 104 is provided within the modular intervertebral disc implant segment, which can be positioned symmetrically or asymmetrically (e.g., offset to one side). Alternatively, the structural void 104 may be configured in a symmetrical or asymmetrical geometric shape. In other embodiments, multiple structural voids 104 are used, which can also be incorporated symmetrically or asymmetrically into the modular intervertebral disc implant segment. Multiple voids 104 within the same (or adjacent) modular intervertebral disc implant segment may have the same or different void 104 shapes.

[0058] An alternative embodiment of structural voids (e.g., open spaces) involves using a first material (e.g., PEEK) in close proximity to one or more adjacent portions with higher compressibility. This allows the first material to be compressed, bent, or otherwise flexed into a highly compressible receiving region. For example, in some embodiments, the structural voids 104A, 104B, 104C, 104D, and 104n may not simply be portions machined from the first material, but may be composed of a material with a higher compressibility than the material constituting the implant segments 100A to 100n.

[0059] Therefore, the overall compressibility is influenced by the material used in at least the highly compressible portion (pure void (e.g., air), fluid, gel, foam, and / or other material more compressible than the first material (e.g., PEEK)). The first material may be substantially incompressible (or at least negligibly compressible), or it may have some degree of compressibility itself. In some embodiments, the first material and / or the second more compressible material may each be made from a homogeneous material, or one or both may be made from a heterogeneous material.

[0060] In a specific example of the embodiment shown in Figure 1, a modular intervertebral disc implant segment structure made of PEEK is employed. In this structure, one or more structural voids 104A, 104B, 104C, 104D, and 104n are incorporated into each modular intervertebral disc implant segment 100A to 100n, which may include structural means to facilitate their interconnection during surgical implantation. Modular intervertebral disc implant segments can be manufactured by known methods including, but are not limited to, extrusion, molding (e.g., injection molding, compression molding, blow molding, etc.), 3D printing, casting, etc.

[0061] Therefore, exemplary modular intervertebral disc implant segment structures may provide other designs that facilitate compression in the target area, while incorporating columns, arms, support layers, trusses, "leaf spring" designs, and / or structural supports as needed.

[0062] Figure 2A shows a specific embodiment of such a modular intervertebral disc implant segment. The embodiment in Figure 2A can be constructed from polymers, metals, and / or other biocompatible materials, but the following description will focus on the use of PEEK. PEEK may have a compressive modulus similar to that of human bone, thus providing a relatively natural structure for constructing a nucleus pulposus prosthesis. PEEK may also exhibit properties that promote smooth, or relatively unimpeded, movement and sliding between segments as adjacent modular intervertebral disc implant segments are sequentially implanted into the target intervertebral disc space. Furthermore, PEEK may exhibit excellent durability, so long-term benefits from the intervertebral disc prosthesis can be expected. The principles described herein are similarly applicable to other materials and compounds exhibiting all or some of these properties, such as metals and other polymers. For example, in one embodiment, a titanium alloy is used for the body of the modular intervertebral disc implant segment.

[0063] Figure 2A shows a representative embodiment of a modular intervertebral disc implant segment 200 that can form part of an intervertebral disc prosthesis comprising multiple modular intervertebral disc implant segments 200. The representative embodiment in Figure 2A comprises multiple structural voids with a degree of symmetry, including compression absorption spaces 202A, 202B, 202C, 202D, 202E, and 202F. These spaces or voids are strategically positioned, shaped, contoured, or otherwise arranged to appropriately balance the absorption and resistance of compression ultimately brought about by spinal movement in a human recipient.

[0064] A typical modular intervertebral disc implant segment 200 further includes an insertion assist mechanism 204 to assist in inserting the implant segment 200 into the target intervertebral disc space. In the illustrated embodiment, the insertion assist mechanism 204 guides the modular intervertebral disc implant segment into the target intervertebral disc space and includes a female threaded hole for receiving a screw-in device that can be used for fixation in some embodiments. The modular intervertebral disc implant segment may also be provided with an optional connection mechanism to facilitate surgical placement in the intervertebral disc within the annulus fibrosus.

[0065] A typical modular intervertebral disc implant segment 200 shown in Figure 2A also includes a connecting mechanism 206. In this embodiment, it consists of a slip-fit ​​component including a male connector 206A and a female connector 206B. Thus, a tool connected to the modular intervertebral disc implant segment 200 via a female screw hole 204 allows for easy connection of the male connector 206A to the female connector 206B of an adjacent modular intervertebral disc implant segment, thereby connecting two adjacent implant segments 200. The male connector 206A and female connector 206B also facilitate proper alignment of adjacent implant segments during connection. In some embodiments, “connection” refers to an interface or mating of physical elements, while in other embodiments, the connection is made stronger by functioning as a coupled coupling. In some embodiments, the interface, mating, or interconnection mechanism may be provided by intersecting physical components (e.g., tongue and groove), interconnecting physical components (e.g., slip-fit), etc. In one interconnected configuration, mating physical components may be configured to form an interlocking mating to provide a retaining force and thereby prevent unintended separation of adjacent parts.

[0066] In yet another embodiment, magnetism can be used to interlock adjacent modular intervertebral disc implant segments. For example, part or all of the upper half of the modular intervertebral disc implant segment 200 may include a magnetic material magnetized to a first polarity (e.g., north pole), and part or all of the lower half of the implant segment 200 may include a magnetic material magnetized to a second polarity (e.g., south pole). This can facilitate magnetic snap-fitting between two adjacent modular intervertebral disc implant segments (with or without additional physical interlocking or connecting components). In such embodiments, the magnetic material within the modular intervertebral disc implant segment may also function as a radiopaque marker to enhance visibility during surgery.

[0067] Figure 2B shows the various faces of a typical isometric modular intervertebral disc implant segment 200 shown in Figure 2A. The faces shown include the left side, front, right side, back, top, and bottom, and the reference numbers used in Figure 2A are also included in Figure 2B.

[0068] Figure 2C shows multiple cross-sectional views of the isometric modular intervertebral disc implant segment 200 shown in Figure 2A. In the illustrated embodiment, cross-sections are shown along the XY, YZ, and XZ planes.

[0069] Figure 2D shows multiple cross-sectional views of the opposite side of the isometric modular intervertebral disc implant segment 200 shown in Figure 2A. From this figure, one embodiment of the male connector 206A of the connection mechanism 206 can be seen.

[0070] Figure 2E shows a typical method for connecting two (or more) modular intervertebral disc implant segments 200A, 200B. In one embodiment, these segments 200A, 200B are connected as segment 200A is inserted into the intervertebral disc cavity formed by removing the existing nucleus pulposus, and then the adjacent segment 200B is inserted into the intervertebral disc cavity. In the illustrated embodiment, the male connector 206A of the first modular intervertebral disc implant segment 200A slides along the groove (female connector) 206B of the adjacent modular intervertebral disc implant segment 200B, for example, in a slip-fit ​​configuration. In one embodiment, the shape of the male connector 206A within the female connector 206B holds the two modular intervertebral disc implant segments 200A, 200B. In other embodiments, the two modular intervertebral disc implant segments 200A, 200B may be held in the desired relative position by frictional or interference mating instead or in addition.

[0071] Figure 2F shows an example of a disc nucleus prosthesis 210 formed by multiple connected modular disc implant segments 200. In this embodiment, five modular disc implant segments are used, including three internal modular disc implant segments 200 and first and second terminal modular disc implant segments 201A and 201B. In one embodiment, the terminal modular disc implant segments 201A and 201B are open on only one side in the illustrated embodiment, and therefore their structural arrangement may differ from that of the internal modular disc implant segments 200. A cross-sectional view 211 of a typical disc nucleus prosthesis 210 shows the interior of the assembly of modular disc implant segments, including the male connector 206A and female connector 206B of the connecting mechanism 206. As described above, the male connector 206A and female connector 206B of the connection mechanism 206 hold the modular intervertebral disc implant segments together to form an integrated intervertebral disc nucleus prosthesis 210, thereby functioning as a movement support device.

[0072] In one embodiment, the size of the intervertebral disc nucleus prosthesis 210 relative to the target intervertebral disc space is set to eliminate or limit migration of the excised nucleus pulposus. For example, in one embodiment, the size of the intervertebral disc nucleus prosthesis 210 is set to be equal to or larger than the target intervertebral disc space (at least in some dimensions). In other embodiments, the size of the intervertebral disc nucleus prosthesis 210 may be smaller than the target intervertebral disc space, but it is preferable that it is substantially held in place so as to minimize internal migration.

[0073] Figure 2G shows several views of a typical intervertebral disc nucleus prosthesis 210 shown in Figure 2F. Figure 2G shows isometric projections, lateral, top, front, and posterior views of each terminal modular intervertebral disc implant segment 201A, 201B. When external pressure is applied to such an intervertebral disc nucleus prosthesis 210 (e.g., pressure due to lateral, anterior, and / or posterior movement of the patient wearing the prosthesis), the pressure-receiving portion can flex inward to absorb and respond to the applied pressure.

[0074] Figure 2H shows exploded views of modular intervertebral disc implant segments 200, 201A, and 201B of an intervertebral disc nucleus prosthesis 210 consisting of five components. This figure shows typical methods for connecting the modular intervertebral disc implant segments, such as the male connector 206A of a connecting mechanism 206 (the receptive / female connector 206B is not shown in Figure 2H). In one embodiment, the male connector 206A may slide along a receptive groove (not shown) of an adjacent modular intervertebral disc implant segment. In one embodiment, adjacent modular intervertebral disc implant segments may be fixed, for example, by a set screw in an insertion assist mechanism 204, thereby reinforcing the connection between segments. In other embodiments, no such set screws or other additional connecting means are used in addition to the physical mating of the connecting elements.

[0075] Figure 2I shows another embodiment of a disc nucleus prosthesis 210B formed by a plurality of connected modular disc implant segments 200. In the illustrated embodiment, the disc nucleus prosthesis 210B includes fewer modular disc implant segments than the examples in Figures 2F and 2G. This illustrates that the disc nucleus prostheses described herein may have any size and any number of disc implant segments (whether or not they include terminal modular disc implant segments). In the illustrated embodiment, the total number of modular disc implant segments is three. In particular, this exemplary disc nucleus prosthesis 210B includes one internal modular disc implant segment 200 and two terminal modular disc implant segments 201A and 201B.

[0076] Figure 2J shows a typical terminal modular intervertebral disc implant segment 201A. In this embodiment, the insertion assist mechanism 204 (e.g., a female screw hole) is accessible through the access space 212 within the terminal modular intervertebral disc implant segment 201A. In the figure, the female connector 206B of the connection mechanism 206 is visible, ready to receive the male connector 206A from an adjacent modular intervertebral disc implant segment to interconnect the segments. Furthermore, the pivot hinges 212A and 212B can further facilitate flexion into the structural gap formed by the structure of the terminal modular intervertebral disc implant segment 201A, in addition to the structure itself.

[0077] Examples in Figures 2A–2J show typical modular connectable segments that provide an intervertebral disc prosthesis assembled in situ with one or more modular connectable segments. A modular connectable segment may be composed of a generally inelastic material that is compressible into one or more integrated spaces or voids. For example, in one embodiment, a modular intervertebral disc implant segment is provided that includes one or more structural gaps, openings, slits, or other structural voids to facilitate compression of the implant segment in response to external forces. Here, the implant segment is configured to return to its original geometric shape in response to a decrease in external forces.

[0078] Figure 3A shows another embodiment of the intervertebral disc nucleus prosthesis 310 based on the principles of this disclosure. This embodiment includes first and second terminal modular intervertebral disc implant segments 301A, 301B, and three intermediate modular intervertebral disc implant segments 300. Set screws 303 show a typical method for fixing the modular intervertebral disc implant segments to each other. When the modular intervertebral disc implant segments 300, 301A, and 301B are interconnected, the intervertebral disc nucleus prosthesis 310 shown in Figure 3B is formed.

[0079] Figure 3C shows another typical configuration of structural spaces in a modular intervertebral disc implant segment. In this embodiment, the structural spaces are represented by slits or opening channels terminating at the opposite end of the modular intervertebral disc implant segment 300. These structural spaces allow for flexion / flexion of arms 314A, 314B, promoting overall compression of the intervertebral disc nucleus prosthesis 310. As in other embodiments, this “leaf spring” structure appropriately balances the absorption and resistance of compression that may ultimately result from spinal movement in human recipients.

[0080] Figure 3D shows four views of a typical modular intervertebral disc implant segment 300 shown in Figures 3A-3C. Figure 3D shows the position of the gaps 302A and 302B (structural gaps) between the arms 314A and 314B relative to the internal body of the modular intervertebral disc implant segment 300 itself. Figure 3D also shows a connection mechanism including a male connector 306 that can be used for alignment and connection with another adjacent implant segment 300. Furthermore, Figure 3D shows another embodiment of an insertion assist mechanism 304 that assists in inserting the implant segment 300 into the target intervertebral disc space. In the illustrated embodiment, the insertion assist mechanism 304 has a female threaded hole that receives a screw-in device, which can be used to guide the modular intervertebral disc implant segment into the target intervertebral disc space and, in some embodiments, to fix it in place. Figure 3E shows additional details of the embodiments described in relation to Figures 3A-3D.

[0081] Figure 4 shows a typical embodiment in which modular intervertebral disc implant segments can be implanted within the annulus fibrosus 401. A typical implantation tool 400 is connected to the modular intervertebral disc implant segments 402 to guide them through access openings 404 formed in the annulus fibrosus 401, facilitating the interconnection and / or interconnection of adjacent modular intervertebral disc implant segments. In this way, the target intervertebral disc cavity 406 can be fitted with the integrated intervertebral disc nucleus prosthesis described herein.

[0082] Figure 5 shows a typical process by which a surgeon implants an integrated disc implant as described herein. In this embodiment, the surgeon can utilize modular disc implant segments. Each segment is made of a material configured to have structural voids that allow for compression in response to external forces and to return to its original geometric shape as the external force decreases. This process includes implanting a first modular disc implant segment. When implanting a second modular disc implant segment, the surgeon may connect the second modular disc implant segment to the first modular disc implant using the connecting mechanisms provided on each of the first and second modular disc implant segments. The final modular disc implant segment is then implanted to form an integrated disc implant within the patient's body.

[0083] This disclosure can solve many of the problems of the prior art, including problems related to insertion and biomaterials. In one embodiment, a solution is provided by using a single known biocompatible thermoplastic material and utilizing the excellent flexural fatigue properties of the material in a unique design that provides a compressive modulus similar to that of natural nucleus pulposus for the moving segment at all ranges of motion, while also making the compressive modulus of the material itself similar to that of bone.

[0084] In such embodiments, surgeons can restore normal disc height and re-tensile the annulus fibrosus fibers to establish a physiological load-shaping relationship between the annulus fibrosus and the nucleus pulposus.

[0085] Embodiments described herein may include a simple yet robust fixing system for enabling rapid, repeatable, easy-to-learn, and reliable module porting.

[0086] As described herein, the present invention includes various representative embodiments disclosed herein, and those skilled in the art will be able to understand other embodiments by teaching herein. Other representative / exemplary embodiments are also described herein.

[0087] In one representative embodiment, an intervertebral disc nucleus pulposus replacement device is provided that incorporates a leaf spring structure that provides the compressibility necessary to mimic the original nucleus pulposus in order to enable movement between adjacent vertebrae.

[0088] In other specific embodiments, such a disc nucleus pulposus replacement device (also referred to herein as “implant”) is composed of a non-elastomer material with one or more movable leaves (connected to the implant body but separated by open channels), and the entire implant is compressible. In a more specific representative embodiment, two or more leaf springs are configured in each module. In other more specific embodiments, the material comprises polyetheretherketone (PEEK), and in some embodiments, the material is composed entirely of PEEK.

[0089] In yet another embodiment of such an intervertebral disc nucleus pulposus replacement device, the material may include a thermoplastic material. In yet another embodiment, the material may include an elastomer, and in yet another embodiment, the material may include a composite material of an elastomer and a thermoplastic material. In yet another embodiment, the material may include a metal, and in yet another embodiment, the material may include a composite material of a metal and a polymer (e.g., an elastomer or a thermoplastic material).

[0090] In other specific embodiments of such intervertebral disc nucleus pulposus replacement devices, the material may have a hardness similar to or comparable to bone, or a compressive modulus similar to or comparable to bone.

[0091] In other specific embodiments, the implant includes two or more modules so that it can be inserted through a path within the annulus fibrosus. In a more specific embodiment, the module includes a channel configured in a Z shape such that the opening end of the upper channel faces posteriorly and the opening end of the lower channel faces anteriorly. In an alternative, more specific embodiment, the module includes a channel configured in a Z shape such that the opening end of the upper channel faces anteriorly and the opening end of the lower channel faces posteriorly. In yet another embodiment, the implant may be inserted via a sequential expander and a traction device. In yet another embodiment, the anterior opening channel may terminate in a substantially circular space that expands posteriorly to improve the compressibility of the leaf element. In yet another embodiment, the posterior opening channel may terminate in a substantially circular space that expands anteriorly to improve the compressibility of the leaf element.

[0092] In other embodiments, the disc nucleus pulposus replacement device may be configured for insertion via posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), and lateral approach.

[0093] In another embodiment, an intervertebral disc nucleus pulposus replacement device is provided having one or more structural voids within a substantially non-elastomer component. These structural voids facilitate the compressibility of the substantially non-elastomer component near the one or more structural voids when placed within the intervertebral disc as a replacement for the original nucleus pulposus.

[0094] The above description of representative embodiments is provided for illustrative and explanatory purposes only. It is not exhaustive and is not intended to limit the disclosed forms themselves. In light of the above teachings, many modifications and variations are possible without departing from the broader scope and spirit of this disclosure. Accordingly, the teachings in this specification and drawings are illustrative and not limiting. The present invention encompasses substitutions, modifications, and equivalents that fall within the scope and spirit of the principles described herein and / or in the appended claims.

[0095] The accompanying drawings, which constitute part of this disclosure, illustrate, but do not limit, specific representative embodiments that can implement the disclosed concepts. Therefore, this detailed description should not be construed as restrictive, and the scope of the various embodiments is defined solely by the entire scope of the accompanying claims and their equivalents.

[0096] In this specification, for convenience, embodiments of the innovative subject matter may be collectively or individually referred to as "the Invention," but even if multiple concepts are disclosed, there is no intention to limit the scope of this application to a single invention or inventive concept. Accordingly, although specific embodiments are illustrated and described herein, any specific illustrated embodiment may be replaced by any configuration designed to achieve the same objective. This disclosure is intended to encompass all adaptations or variations of various embodiments. Those skilled in the art will be able to recognize, by considering the above description, combinations of the embodiments described above, as well as other embodiments not expressly described herein.

Claims

1. Intervertebral disc nucleus pulposus replacement device, Equipped with multiple modular intervertebral disc implant segments, At least one of the plurality of implant segments includes one or more structural voids that facilitate compression of the implant segment in response to an external force, and is configured to return to its original geometric shape in response to a decrease in the external force. Each of the plurality of implant segments is provided with a mounting mechanism for connecting the implant segment to at least one other implant segment. The system comprises an integrated structure consisting of a connector for the multiple implant segments, Intervertebral disc nucleus pulposus replacement device.

2. In the intervertebral disc nucleus pulposus replacement device according to claim 1, At least one of the structural gaps is configured as a leaf spring having a gap with one or more open ends. Intervertebral disc nucleus pulposus replacement device.

3. In the intervertebral disc nucleus pulposus replacement device according to claim 1, At least one of the structural gaps is configured as a leaf spring having one or more closed internal spaces. Intervertebral disc nucleus pulposus replacement device.

4. In the intervertebral disc nucleus pulposus replacement device according to claim 1, Each of the aforementioned modular intervertebral disc implant segments is composed of polyether ether ketone. Intervertebral disc nucleus pulposus replacement device.

5. In the intervertebral disc nucleus pulposus replacement device according to claim 1, Each of the aforementioned modular intervertebral disc implant segments is made of titanium alloy. Intervertebral disc nucleus pulposus replacement device.

6. In the intervertebral disc nucleus pulposus replacement device according to claim 1, The mounting mechanism further includes an implant segment connection mechanism that can be coupled to an implant segment connection mechanism of an adjacent modular intervertebral disc implant segment. Intervertebral disc nucleus pulposus replacement device.

7. In the intervertebral disc nucleus pulposus replacement device according to claim 6, The implant segment connection mechanism includes a tongue-shaped element and a groove, The groove is configured to facilitate slip-fit ​​connections by receiving the tongue-shaped elements of adjacent modular intervertebral disc implant segments. Intervertebral disc nucleus pulposus replacement device.

8. In the intervertebral disc nucleus pulposus replacement device according to claim 6, The implant segment connection mechanism includes either a tongue-shaped element or a groove, The tongue-shaped element or groove provided in the first modular intervertebral disc implant segment is configured to engage with a corresponding groove or tongue-shaped element provided in an adjacent modular intervertebral disc implant segment to facilitate a slip-fit ​​connection. Intervertebral disc nucleus pulposus replacement device.

9. In the intervertebral disc nucleus pulposus replacement device according to claim 1, Each of the aforementioned modular intervertebral disc implant segments is equipped with a tool connection mechanism that is detachably connected to the installation device. Intervertebral disc nucleus pulposus replacement device.

10. In the intervertebral disc nucleus pulposus replacement device according to claim 1, The one or more structural spaces are arranged symmetrically within at least one of the modular intervertebral disc implant segments. Intervertebral disc nucleus pulposus replacement device.

11. In the intervertebral disc nucleus pulposus replacement device according to claim 1, The one or more structural spaces are asymmetrically arranged within at least one of the modular intervertebral disc implant segments. Intervertebral disc nucleus pulposus replacement device.

12. In the intervertebral disc nucleus pulposus replacement device according to claim 1, The one or more structural voids include a superstructure void group and a substructure void group, The superstructure voids and the substructure voids are separated by a less compressible central portion. Intervertebral disc nucleus pulposus replacement device.

13. In the intervertebral disc nucleus pulposus replacement device according to claim 1, The terminal modular intervertebral disc implant segment further comprises having one or more structural gap arrangements different from at least one of the plurality of implant segments. Intervertebral disc nucleus pulposus replacement device.

14. A method of implanting a disc prosthesis into a patient, A step of preparing multiple modular intervertebral disc implant segments, wherein each modular intervertebral disc implant segment is made of a material configured to have multiple structural voids that facilitate compression in response to external forces, and to return to its original geometric shape in response to a decrease in external forces, The process involves implanting the first modular intervertebral disc implant segment, In connection with implanting a second modular intervertebral disc implant segment, the process involves connecting the second modular intervertebral disc implant segment to the first modular intervertebral disc implant segment using the connection mechanisms provided on each of the first and second modular intervertebral disc implant segments, The process includes implanting the final modular intervertebral disc implant segment to form a collective intervertebral disc prosthesis within the patient's body, method.

15. In the method according to claim 14, The process further includes implanting one or more additional modular intervertebral disc implant segments between the first modular intervertebral disc implant segment and the last modular intervertebral disc implant segment via the respective connecting mechanisms. method.

16. In the method according to claim 14, Each of the aforementioned modular intervertebral disc implant segments contains polyether ether ketone, method.

17. In the method according to claim 14, The procedure further includes connecting an insertion tool to the connection receiving portion of a second modular intervertebral disc implant segment to assist in the insertion of the second modular intervertebral disc implant segment into the intervertebral disc space within the annulus fibrosus, and then disconnecting the insertion tool from the connection receiving portion after the second modular intervertebral disc implant segment has been connected to the first modular intervertebral disc implant segment via the respective connection mechanisms. method.

18. Intervertebral disc nucleus pulposus replacement implant, It features a leaf spring structure that provides the necessary compressibility to mimic the original nucleus pulposus, enabling movement between adjacent vertebral bodies. Intervertebral disc nucleus pulposus replacement implant.

19. In the intervertebral disc nucleus pulposus replacement implant according to claim 18, The aforementioned intervertebral disc nucleus pulposus replacement implant is made of a non-elastomer material and includes one or more movable leaf springs that are separated from the main body by an open channel while being connected to the main body, thereby allowing the entire implant to be compressed. Intervertebral disc nucleus pulposus replacement implant.

20. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The open front channel terminates in a roughly circular space that expands towards the rear to improve the compressibility of the leaf spring structure. Intervertebral disc nucleus pulposus replacement implant.

21. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The open rear channel terminates in a roughly circular space that expands towards the rear to improve the compressibility of the leaf spring structure. Intervertebral disc nucleus pulposus replacement implant.

22. In the intervertebral disc nucleus pulposus replacement implant according to claim 18, The plate-shaped elements of the aforementioned leaf spring structure maintain their connection to the main body of the implant, forming an open channel, and the multiple arch-shaped spring structures provide compressibility during flexion, extension, and lateral flexion of the vertebral movement segment. Intervertebral disc nucleus pulposus replacement implant.

23. In the intervertebral disc nucleus pulposus replacement implant according to claim 18, The leaf spring structure includes a combination of open and closed leaf spring elements configured to optimize the flexibility of the implant during all movements of the vertebral body. Intervertebral disc nucleus pulposus replacement implant.

24. In the intervertebral disc nucleus pulposus replacement implant according to claim 18, The material of the intervertebral disc nucleus pulposus replacement implant has a hardness or compressive modulus similar to that of bone. Intervertebral disc nucleus pulposus replacement implant.

25. In the intervertebral disc nucleus pulposus replacement implant according to claim 18, The aforementioned intervertebral disc nucleus pulposus replacement implant is composed of two or more modules, so that each of the two or more modules can be individually inserted through a pathway within the annulus fibrosus. Intervertebral disc nucleus pulposus replacement implant.

26. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, Each module has a channel configured in a Z shape such that the first open end of the upper channel faces rearward and the second open end of the lower channel faces forward. Intervertebral disc nucleus pulposus replacement implant.

27. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The module has a channel configured in a Z shape such that the first open end of the lower channel faces rearward and the second open end of the upper channel faces forward. Intervertebral disc nucleus pulposus replacement implant.

28. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, Each of the multiple modules consists of two or more leaf springs. Intervertebral disc nucleus pulposus replacement implant.

29. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The material for the aforementioned intervertebral disc nucleus pulposus replacement implant is PEEK (polyether ether ketone). Intervertebral disc nucleus pulposus replacement implant.

30. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The material of the aforementioned intervertebral disc nucleus pulposus replacement implant includes a thermoplastic material. Intervertebral disc nucleus pulposus replacement implant.

31. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The material of the intervertebral disc nucleus pulposus replacement implant includes a composite material of metal and polymer, wherein the polymer includes an elastomer or thermoplastic material. Intervertebral disc nucleus pulposus replacement implant.

32. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The material of the aforementioned intervertebral disc nucleus pulposus replacement implant includes an elastomer. Intervertebral disc nucleus pulposus replacement implant.

33. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The material of the aforementioned intervertebral disc nucleus pulposus replacement implant includes metal. Intervertebral disc nucleus pulposus replacement implant.

34. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The material of the aforementioned intervertebral disc nucleus pulposus replacement implant includes a composite material of metal and an elastomer or thermoplastic polymer. Intervertebral disc nucleus pulposus replacement implant.

35. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, The aforementioned implant is configured for insertion via posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), and lateral approach. Intervertebral disc nucleus pulposus replacement implant.

36. In the intervertebral disc nucleus pulposus replacement implant according to claim 19, Each module forming the intervertebral disc nucleus pulposus replacement implant is sequentially inserted using a dilator and a traction device. Intervertebral disc nucleus pulposus replacement implant.

37. A device for creating a space between two adjacent vertebral bodies, It comprises multiple members that are arranged coaxially, expand the annulus fibrosus, and apply force to the vertebral endplate to increase the intervertebral distance, and which gradually increase in size. The final of the plurality of members is sized to provide a desired endplate spacing and has an inner diameter that allows the device and intervertebral implant module to pass through. Device.

38. A spinal disc nucleus pulposus replacement device, It has one or more structural voids substantially located within the non-elastomer component, The aforementioned structural voids, when positioned within the intervertebral disc as a replacement for the original nucleus pulposus, promote the compressibility of the non-elastomer component near one or more of the structural voids. Spinal disc nucleus pulposus replacement device.

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