Full-porous spine fusion cage with extremely-small curved surface structure
The fully porous spinal fusion cage with a minimally curved surface structure solves the problem of poor mechanical properties of lumbar/cervical fusion cages, achieving higher static compressive strength and fatigue strength, and enhancing bone fusion and implantation stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2026-04-07
AI Technical Summary
Existing lumbar/cervical fusion devices have poor mechanical properties and require the design of a solid frame to improve mechanical load-bearing capacity. However, the solid part cannot achieve bone ingrowth, which affects the fusion effect.
The fully porous spinal fusion device with a minimally curved surface structure uses a minimally curved porous structure formed by a three-cycle helical (Gyroid) surface, combined with a bone graft window and instrument clamping area. The materials selected are medical-grade pure tantalum, tantalum-containing alloys, titanium alloys and polyetheretherketone, and the porosity, pore size and wall thickness are optimized to increase the bone contact area and bone tissue ingrowth space.
It improves static compressive strength and fatigue strength by more than 50%, its elastic modulus matches that of human bones, and its stress load is evenly distributed, enhancing bone fusion and vascularization, and improving implantation stability and bone fusion effect.
Smart Images
Figure CN224085509U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of medical device technology, and in particular to a fully porous spinal fusion device with a minimal curved surface structure. Background Technology
[0002] Currently, lumbar / cervical fusion surgery is one of the commonly used methods for treating lumbar / cervical spine diseases in clinical practice. Lumbar / cervical fusion surgery involves surgically implanting a lumbar / cervical fusion device into the body. After implantation, the device forms bone fusion with the vertebrae above and below it to maintain the height and physiological curvature of the intervertebral space, stabilize the spine, reduce nerve compression, and relieve pain.
[0003] In existing technologies, lumbar / cervical fusion devices are commonly made of materials such as polyetheretherketone (PEEK), titanium alloys, and tantalum metal. These materials have a dense solid structure, and their mechanical properties, such as elastic modulus, do not match those of human bones. The limited bone contact area leads to poor implantation stability and unsatisfactory bone fusion results.
[0004] With the development of advanced manufacturing technologies such as additive manufacturing (3D printing), spinal fusion devices are gradually upgrading from dense to porous types. However, most existing porous structures are pillar-type porous structures, which have poor mechanical properties and require the design of solid frames to improve mechanical load-bearing capacity. However, the solid parts cannot achieve bone ingrowth, affecting the fusion effect. Utility Model Content
[0005] In view of this, to address the technical problem of poor mechanical performance of existing spinal fusion devices, the need for a solid frame design to improve mechanical load-bearing capacity, and the inability of the solid part to achieve bone ingrowth, thus affecting the fusion effect, this utility model provides a fully porous spinal fusion device with a minimally curved surface structure. It employs a minimally curved porous structure formed by a three-period gyroid surface, resulting in superior comprehensive mechanical properties, with static compressive strength and fatigue strength increased by more than 50%. Its elastic modulus matches the human skeleton well, stress load is evenly distributed, mechanical reliability is high, and fatigue resistance is strong. The fully porous structure, without dense solid parts, increases the contact area with bone and the space for bone tissue ingrowth. Through capillary effect, blood is rapidly drawn into the channels, which is beneficial for bone fusion and vascularization, resulting in outstanding bone conduction, bone fusion, and bone ingrowth performance.
[0006] To achieve the above objectives, this utility model provides the following technical solution:
[0007] A fully porous spinal fusion device with a minimally curved surface structure includes:
[0008] The minimal surface porous structure, which is a three-period helical (Gyroid) surface, has porous structure parameters that follow the mathematical formulas below:
[0009]
[0010] In the formula, a represents the cell size parameter, t represents the porosity parameter, and x, y, and z represent the spatial positions in the Cartesian coordinate system, which determine the pore wall thickness and the number of cells.
[0011] Bone graft windows are set on a pair of arc surfaces of the extremely small curved, porous structure and are used in conjunction with bone grafting.
[0012] The instrument clamping area is located in the middle of the bottom surface of the minimally curved porous structure and communicates with the bone graft window, for the instrument to clamp the spinal fusion device.
[0013] Preferably, the instrument clamping area is a clamping groove.
[0014] Preferably, the porosity of the minimally curved porous structure is 30-90%.
[0015] Preferably, the average pore diameter of the micro-curved porous structure is 0.1 to 1 mm.
[0016] Preferably, the average wall thickness of the micro-curved porous structure is ≤1.5mm.
[0017] Preferably, the unit cell size of the extremely small curved porous structure is ≤10mm.
[0018] Preferably, the bone graft window is rectangular in shape.
[0019] Preferably, it also includes corrugated protrusions disposed on a pair of said arc surfaces to increase friction between the spinal fusion device and the spinal bones.
[0020] Preferably, the bone graft window is disposed on the corrugated protrusion.
[0021] Preferably, the material of the extremely small curved porous structure is one of medical-grade pure tantalum, tantalum-containing alloy, titanium alloy, and polyetheretherketone.
[0022] The minimally curved, fully porous spinal fusion device provided by this invention has the following advantages over existing technologies:
[0023] The extremely small curved surface fully porous structure adopted in this invention has superior comprehensive mechanical properties, with static compressive strength and fatigue strength increased by more than 50%. Its elastic modulus is highly compatible with human bone, there are no stress concentration points in the structure, stress load is evenly distributed, resulting in high mechanical reliability and strong fatigue resistance. The fully porous structure, without dense solid parts, increases the contact area with bone and the space for bone tissue ingrowth. Blood is rapidly drawn into the channels through capillary effect, which is beneficial for bone fusion and vascularization. It exhibits outstanding bone conduction, bone fusion, and bone ingrowth performance, solving the problems of mismatch between the mechanical properties of lumbar / cervical fusion devices and human bone, easy vertebral body subsidence, stress shielding effect, poor implantation stability, and unsatisfactory osteolysis and bone fusion effects caused by the mismatch between the material and the elastic modulus of human bone.
[0024] Furthermore, the spinal fusion device of this invention is designed with human anatomy in mind. Its rectangular bone graft window facilitates bone implantation and growth, while the corrugated protrusions effectively increase the friction between the fusion device and the spinal bone, thereby enhancing post-implantation stability. The optimized design of the porosity, pore size, wall thickness, and unit cell size of the minimally shaped porous structure not only ensures the mechanical strength of the device but also provides a favorable spatial environment for bone ingrowth. In terms of material selection, the use of medical-grade pure tantalum, tantalum-containing alloys, titanium alloys, and polyetheretherketone (PEEK) ensures the device's biocompatibility and corrosion resistance, further improving the safety and success rate of the surgery. Moreover, the elastic modulus and other mechanical properties of these materials match those of human bone. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the lumbar fusion device of this utility model;
[0026] Figure 2 This is a top view of the lumbar fusion device of this utility model;
[0027] Figure 3 This is the front view of the lumbar fusion device of this utility model:
[0028] Figure 4 This is a right-side view of the lumbar fusion device of this utility model;
[0029] Figure 5 This is a schematic diagram of the cervical fusion device of this utility model.
[0030] Figure 6 This is a front view of the cervical fusion device of this utility model;
[0031] Figure 7 This is a side view of the cervical fusion device of this utility model;
[0032] Figure 8 This is a right-side view of the cervical fusion device of this utility model;
[0033] In the figure, 1. Minimal curved porous structure; 2. Clamping groove; 11. Corrugated protrusion; 12. Side view; 13. Bottom surface; 3. Bone graft window. Detailed Implementation
[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.
[0035] In the description of this utility model, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0036] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0037] This utility model provides a fully porous spinal fusion device with a minimally curved surface structure, comprising:
[0038] Minimal surface porous structure 1, which is a three-period helical (Gyroid) surface, has porous structure parameters that follow the following mathematical formula:
[0039]
[0040] In the formula, a represents the cell size parameter, t represents the porosity parameter, and x, y, and z represent the spatial positions in the Cartesian coordinate system, which determine the pore wall thickness and the number of cells.
[0041] like Figure 1-8 The diagram illustrates lumbar and cervical fusion devices.
[0042] Among them, the fully porous spinal fusion cage with a minimal curved surface structure is applicable to lumbar and cervical fusion cages.
[0043] A three-period helical surface is a surface with a specific periodic structure, whose equation describes a specific form of helical motion. It possesses a series of helical shapes and textures, forming a unique spatial morphology and surface structure. These structural features give the surface unique optical properties and surface characteristics. Theoretically, a three-period helical (Gyroid) surface is a continuous surface without solid parts. The surface of this minimal porous structure 1 includes a pair of opposing arc surfaces, a pair of opposing side surfaces 12, and a bottom surface 13.
[0044] This invention does not have a dense solid framework; its overall structure is a three-dimensional interconnected, extremely small curved, fully porous structure, which has superior mechanical properties and bone fusion ability, as well as longer implantation stability and service life.
[0045] like Figure 1 As shown, the overall shape of the extremely curved porous structure 1 is symmetrical. Its surface has a pair of arc surfaces with corrugated protrusions 11 arranged opposite each other, a pair of side surfaces 12 arranged opposite each other, and a bottom surface 13, which is connected to the pair of corrugated protrusions 11 and the pair of side surfaces 12 respectively.
[0046] Bone graft window 3 is located on the arc surface of a pair of corrugated protrusions 11 in the minimally shaped porous structure. Bone graft window 3 refers to a window or channel created during orthopedic surgery to facilitate bone grafting and promote bone fusion. When placing a lumbar / cervical fusion cage, autologous bone graft material or artificial bone material needs to be injected into the minimally shaped porous structure to fill it and solidify it, thus enabling long-term placement and connection between the lumbar / cervical vertebrae. It can be understood that bone graft window 3 is the window for injecting bone material into the minimally shaped porous structure. It can be understood that autologous bone graft material is obtained from the patient's body and therefore will not cause rejection. Artificial bone material refers to artificial biomaterials that can replace human bone or repair bone tissue defects, including inorganic materials mainly composed of calcium and phosphorus and organic materials composed of collagen and other matrices.
[0047] The shape of the bone graft window 3 is rectangular. Based on the patient's bone characteristics, bone grafting needs and the overall design of the fusion device, the maximum size of the bone graft window 3 is 14mm×6mm and the minimum size is 0mm×0mm, that is, no bone graft window 3 is set.
[0048] The instrument clamping area is located in the middle of the bottom surface 13 of the minimally curved porous structure 1 and communicates with the bone graft window 3. It is used for the instrument to clamp the spinal fusion device, which facilitates the clamping and implantation of the spinal fusion device during surgery.
[0049] In this invention, the instrument clamping area is the clamping groove 2.
[0050] In this invention, the porosity of the minimally curved porous structure 1 is 30-90%, preferably 50-70%. Porosity refers to the percentage of pore volume to the total volume of a bulk material in its natural state. It is understood that when a spinal (lumbar / cervical) fusion device is placed on the lumbar / cervical vertebrae of different individuals or at different locations on the lumbar / cervical vertebrae, the required load-bearing capacity and bone condition differ. The porosity of the spinal fusion device determines its load-bearing capacity and bone condition. More specifically, the porosity of the spinal fusion device provided by this invention is 50%–70%. In broader applications, the porosity of the lumbar fusion device can be 30%–90%.
[0051] In this utility model, the average pore diameter of the extremely small curved porous structure 1 is 0.1-1 mm, preferably 0.3-0.8 mm, specifically:
[0052] The pores of the minimally shaped, fully porous structure are regular circular holes, and their diameter refers to the diameter corresponding to each porosity. More specifically, when a lumbar / cervical fusion device is installed behind the lumbar / cervical spine, the body's tissue fluid will infiltrate the minimally shaped, fully porous structure through its pores, thereby inducing osteoblast formation and promoting new bone growth. Therefore, the pore size cannot be too large or too small. In this invention, the average pore diameter of the minimally shaped, fully porous structure is 0.3–0.8 mm. In broader applications, the average pore diameter of the spinal fusion device can be 0.1–1 mm.
[0053] In this invention, the average wall thickness of the minimally curved porous structure 1 is ≤1.5mm, preferably 0.3~0.6mm. Specifically:
[0054] Specifically, the shape of the minimally curved porous structure is a periodically repeating ordered porous structure, that is, the minimally curved porous structure 1 is formed by a large number of periodic plate-like connections. In this utility model, the average wall thickness of the minimally curved porous structure 1 is 0.3 to 0.6 mm. In a wider range of application scenarios, the average wall thickness of the spinal fusion device is ≤1.5 mm.
[0055] In this invention, the unit cell size of the extremely small curved porous structure 1 is ≤10mm, preferably 1~5mm.
[0056] In this invention, the bone graft window 3 is rectangular in shape. It is used to fill the porous structure 1 with autologous bone graft material or artificial bone material.
[0057] This invention also includes corrugated protrusions 11, which are disposed on a pair of said arc surfaces to increase the friction between the spinal fusion device and the spinal bones.
[0058] In this invention, the bone graft window 3 is disposed on the corrugated protrusion 11. The clamping groove 2 is preferably disposed in the middle of the rear side 12 for the instrument to clamp the spinal fusion device.
[0059] In this invention, the material of the extremely small curved porous structure 1 is one of medical-grade pure tantalum, tantalum-containing alloy, titanium alloy, and polyetheretherketone. Because this invention is an extremely small curved porous structure, the elastic modulus and other mechanical properties of these materials match those of human bone.
[0060] The above are merely preferred embodiments of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.
Claims
1. A fully porous spinal fusion device with a minimally curved surface structure, characterized in that, include: The minimal surface porous structure, which is a three-period helical (Gyroid) surface, has porous structure parameters that follow the mathematical formulas below: In the formula, a represents the cell size parameter, t represents the porosity parameter, and x, y, and z represent the spatial positions in the Cartesian coordinate system, which determine the pore wall thickness and the number of cells; The bone graft window is located on a pair of arc surfaces of the extremely small curved, fully porous structure; The instrument clamping area is located in the middle of the bottom surface of the minimally curved porous structure and communicates with the bone graft window, for the instrument to clamp the spinal fusion device.
2. The minimally curved surface structure fully porous spinal fusion device according to claim 1, characterized in that, The instrument clamping area is a clamping groove.
3. The minimally curved surface structure fully porous spinal fusion device according to claim 1, characterized in that, The porosity of the extremely small curved porous structure is 30-90%.
4. The minimally curved surface structure fully porous spinal fusion device according to claim 1, characterized in that, The average pore diameter of the extremely small curved porous structure is 0.1 to 1 mm.
5. The minimally curved surface structure fully porous spinal fusion device according to claim 1, characterized in that, The average wall thickness of the extremely small curved porous structure is ≤1.5mm.
6. The minimally curved surface structure fully porous spinal fusion device according to claim 1, characterized in that, The unit cell size of the extremely small curved porous structure is ≤10mm.
7. The minimally curved surface structure fully porous spinal fusion device according to claim 1, characterized in that, The bone graft window is rectangular in shape.
8. The minimally curved surface structure fully porous spinal fusion device according to claim 1, characterized in that, It also includes corrugated protrusions disposed on a pair of said arc surfaces to increase friction between the spinal fusion device and the vertebral bones.
9. The minimally curved surface structure fully porous spinal fusion device according to claim 8, characterized in that, The bone graft window is located on the corrugated protrusion.
10. A fully porous spinal fusion device with a minimally curved surface structure according to any one of claims 1-9, characterized in that, The material of the extremely small curved porous structure is one of medical-grade pure tantalum, tantalum-containing alloy, titanium alloy, and polyetheretherketone.