Bionic lumbar intertransverse fusion cage and manufacturing method thereof

Abstract

The application relates to the technical field of medical devices, in particular to a bionic intertransverse process lumbar fusion cage, which comprises a fusion cage main body, two ends of the fusion cage main body are provided with mounting parts, the two mounting parts are used for being detachably assembled on adjacent transverse processes respectively, and the inner side surface of the fusion cage main body is a bionic special-shaped curved surface which is adapted to be attached to the outer side of an articular process; the fusion cage main body comprises a metal solid frame and a porous filling part, the porous filling part is arranged in the metal solid frame so that the fusion cage main body is in a long strip structure as a whole, the metal solid frame is exposed at each edge of the outer surface of the fusion cage main body, and the middle part of the porous filling part is further provided with a bone graft material filling cavity; the pores of the porous filling part are configured to be used for loading bone formation growth factors, drugs or stem cells. The bionic intertransverse process lumbar fusion cage and the manufacturing method thereof can help to improve the intertransverse process bone graft fusion success rate, reduce the risk of postoperative pseudoarthrosis formation, and improve the long-term clinical curative effect of posterolateral fusion.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a bionic lumbar intertransverse process fusion device and its manufacturing method. Background Technology

[0002] Spinal fusion is currently the most fundamental intervention for restoring spinal stability in spinal surgery. Based on the location of fusion, lumbar fusion is mainly divided into two categories: anterior interbody fusion and posterior fusion. Posterior fusion, depending on the placement of the bone graft, can be further subdivided into various procedures such as interlaminar fusion, interspinous fusion, facet joint fusion, and intertransverse process fusion.

[0003] Posterolateral lumbar fusion (PLF) is a commonly used posterior fusion procedure and is widely applied in clinical practice. However, the interbody fusion cages currently widely used in clinical practice are designed for the intervertebral space anatomy, and their external shape and internal fixation methods are difficult to adapt to the anatomical characteristics of the intertransverse region. Furthermore, there are currently no standardized implants specifically designed for intertransverse bone grafting fusion. Therefore, PLF surgery still follows the traditional procedure: the transverse processes of the segment to be fused are extensively exposed during the operation, and the cortical bone is removed from their surface to prepare a bone graft bed. Subsequently, autologous bone, allogeneic bone, or artificial bone material is implanted into the intertransverse region in strip or granular form.

[0004] However, the aforementioned traditional surgical procedures have significant clinical and technical limitations: Because the intertransverse process region lacks an effective mechanical fixation structure, the implanted bone strips or bone fragments are easily compressed by the tension of the paravertebral muscles and soft tissues after surgery. At the same time, the shear stress generated by physiological activities such as spinal flexion, extension and rotation causes the bone graft material to move slightly or drift in spatial position, causing it to deviate from the effective range of the initially planned bone graft bed. This mechanical instability directly leads to a low success rate of intertransverse process bone graft fusion. Some patients even develop serious complications such as pseudoarthrosis due to bone graft nonunion after surgery, which significantly affects the long-term efficacy of the surgery. Summary of the Invention

[0005] This application provides a biomimetic lumbar intertransverse process fusion device and its manufacturing method to improve the following technical problems: PLF surgery still follows the traditional operating procedure, resulting in a low success rate of intertransverse process bone graft fusion. Some patients even experience serious complications such as pseudoarthrosis due to bone graft nonunion, which significantly affects the long-term efficacy of the surgery.

[0006] In the first aspect, this application provides a bionic lumbar intertransverse process fusion device, which adopts the following technical solution: A biomimetic intertransverse process fusion device for lumbar vertebrae and its manufacturing method are disclosed. The device includes a fusion device body, with mounting portions at both ends of the fusion device body. The two mounting portions are respectively detachably assembled onto adjacent transverse processes. The inner surface of the fusion device body is a biomimetic irregular curved surface adapted to fit the outer side of the articular processes. The fusion device body includes a metal three-dimensional frame and a porous filling part. The porous filling part is disposed in the metal three-dimensional frame so that the fusion device body has an overall elongated structure. The metal three-dimensional frame is exposed at each edge of the outer surface of the fusion device body. The middle part of the porous filling part also has a bone graft material filling cavity. The pores of the porous filling part are configured to load osteogenic growth factors, drugs or stem cells.

[0007] In one feasible technical solution of this application, the mounting part is fixed by screws and includes two bone graft screws. The two ends of the fusion device body are provided with perforations, and the bone graft screws pass through the perforations and are threaded into the transverse protrusion.

[0008] In one feasible technical solution of this application, metal sleeves are fixed inside both ends of the metal three-dimensional frame, the perforation is formed in the metal sleeve, and the metal sleeve has a groove for receiving the cap of the bone graft screw.

[0009] In one feasible technical solution of this application, the three-dimensional metal frame and the two metal sleeves are both titanium metal parts or titanium alloy parts and are welded and fixed. The porous filling part is integrally solidified and formed in the three-dimensional metal frame by biodegradable magnesium alloy or polylactic acid-hydroxyapatite composite material through 3D printing technology.

[0010] In one feasible technical solution of this application, the mounting part is fixed by hook fixing and includes two locking hooks. The two locking hooks are respectively hinged to both ends of the metal three-dimensional frame. The outer surface and hook tip of the locking hook are both set as arc transition structure.

[0011] In one feasible technical solution of this application, the bone graft material filling cavity is a plurality of spaced circular holes, a single elliptical through hole, a single rectangular through hole or a single oval through hole, and the inner wall of the bone graft material filling cavity is provided with a rough surface or a microporous structure to increase the bonding force with the bone graft material.

[0012] In one feasible technical solution of this application, the width of the fusion body gradually decreases from the middle to both ends, the length of the fusion body is 28-36mm, the width of the fusion body is 8-15mm, and the thickness of the fusion body is 5-10mm.

[0013] In one feasible technical solution of this application, the porosity of the porous filling part is 50% to 80% and the pore size is 100 to 600 μm.

[0014] In one feasible technical solution of this application, the porosity of the porous filling part is 60% to 75% and the pore size is 200 to 400 μm.

[0015] Secondly, this application provides a method for manufacturing the bionic lumbar intertransverse process fusion device as described above, employing the following technical solution: A method for manufacturing a biomimetic lumbar intertransverse process fusion device includes the following steps: Based on the patient's lumbar spine CT or MRI image data, a three-dimensional model of the lumbar spine is reconstructed to obtain the anatomical morphological parameters of the transverse process. The three-dimensional model of the fusion device body and mounting part is designed based on the anatomical morphological parameters of the transverse process. The inner side of the fusion device body is a biomimetic irregular curved surface. The fusion device body includes a metal three-dimensional frame and a porous filling part. First, a three-dimensional metal frame is formed by welding titanium metal or titanium alloy. Then, a biodegradable magnesium alloy or polylactic acid-hydroxyapatite composite material is integrally solidified in the three-dimensional metal frame using 3D printing technology to obtain a fusion device body with a long strip structure and a bone graft material filling cavity. The fusion unit body undergoes the following surface treatments: sandblasting, acid etching, anodizing, or coating. Osteogenesis-promoting growth factors, drugs, or stem cells are loaded into the pores of the fusion device body. The methods for loading growth factors or drugs include physical adsorption, impregnation, microsphere embedding, or layer-by-layer self-assembly. The methods for loading stem cells include direct seeding or hydrogel embedding.

[0016] In summary, this application includes at least one of the following beneficial technical effects: By setting mounting parts at both ends of the fusion device body, it can be detachably assembled onto adjacent transverse processes, thereby providing stable mechanical anchoring for the bone graft area. The implanted bone material is thus constrained within the predetermined bone graft bed range between the transverse processes, effectively resisting the tension and compression of paravertebral muscles and soft tissues after surgery, and resisting the shear stress generated by physiological activities such as spinal flexion, extension, and rotation. This significantly reduces the risk of bone graft material displacement and provides a basic guarantee for the stability of bone grafts between transverse processes. The biomimetic irregular curved surface on the inner side of the fusion device is designed to fit the outer side of the articular process, so that the fusion device can closely match the local anatomical shape of the posterolateral lumbar spine. This increases the contact area between the fusion device and the autologous bone surface, which is conducive to the uniform transmission of stress between the fusion device and the host bone. It avoids bone resorption or implant loosening caused by local stress concentration, and also reduces the ineffective gap between the bone graft area and the surrounding soft tissue. This further restricts the bone graft particles from escaping outward or shifting inward, creating a stable local mechanical environment for bone graft fusion. The metal three-dimensional frame is exposed at each edge of the outer surface, forming a load-bearing skeleton. This ensures that the fusion device has sufficient compressive and bending strength when bearing spinal loads, preventing the implant from collapsing or breaking under long-term physiological loads. The porous filling part provides a three-dimensional through porous structure for bone tissue ingrowth, which is conducive to the inward ingrowth of host bone and realizes the bio-integration of the fusion device with autologous bone. Furthermore, the bone graft material filling cavity set in the middle of the porous filling part provides a concentrated space for autologous bone or allogeneic bone particles. Compared with the traditional scattered bone grafting method, this cavity structure allows the bone graft material to be concentrated in the core position of the fusion area, improving the local bone graft density and osteogenic efficiency. At the same time, the pores of the porous filling part also have the ability to load osteogenic growth factors, drugs or stem cells, which can exert active osteogenesis, anti-inflammation or promote angiogenesis biological functions through local sustained release effect in the early postoperative period. Thus, active biological stimulation is superimposed on the basis of dynamic fixation, and the process of intertransverse bony fusion is synergistically promoted. In summary, this fusion device systematically solves the problems of easy displacement of bone graft materials, unstable fusion environment, and insufficient osteogenic activity in traditional PLF procedures through the multi-level structural synergy of "mechanical fixation provided by the two-end mounting parts, anatomical fit achieved by the biomimetic curved surface, structural strength guaranteed by the three-dimensional frame, bone ingrowth supported by the porous filling part, concentrated placement of bone graft material in the bone graft filling cavity, and synergistic induction of osteogenic activity by loading active factors in the pores". This helps to improve the success rate of intertransverse process bone graft fusion, reduce the risk of postoperative pseudoarthrosis, and improve the long-term clinical efficacy of posterolateral spinal fusion. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the bionic lumbar intertransverse process fusion device according to Embodiment 1 of this application; Figure 2This is an exploded structural diagram of the bionic lumbar intertransverse process fusion device according to Embodiment 1 of this application; Figure 3 This is a schematic diagram of the installation of the bionic lumbar intertransverse process fusion device according to Embodiment 1 of this application; Figure 4 This is a flowchart illustrating the manufacturing method of the bionic lumbar intertransverse process fusion device in Embodiment 1 of this application; Figure 5 This is a schematic diagram of the structure of the bionic lumbar intertransverse process fusion device according to Embodiment 2 of this application; Figure 6 This is a schematic diagram of the structure of the bionic lumbar intertransverse process fusion device according to Embodiment 2 of this application.

[0019] Explanation of reference numerals in the attached figures: 1. Metal three-dimensional frame; 2. Porous filling part; 3. Bone graft material filling cavity; 4. Bone graft screw; 5. Metal sleeve; 6. Locking hook; 10. Bionic irregular curved surface. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0021] Definitions of terms that need to be explained in advance: When a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or indirectly on that other component; When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to that other component; The terms “length”, “width”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the attached drawings, and are only for the convenience of description, and do not indicate or imply that there must be a specific orientation. The terms “first” and “second” are used only to distinguish different components and do not indicate importance or quantity. Unless otherwise expressly defined, “multiple” means two or more.

[0022] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0023] Example 1 Reference Figure 1-3This embodiment provides a biomimetic lumbar transverse process fusion device, including a fusion device body, with mounting parts at both ends of the fusion device body. The two mounting parts are used to be detachably assembled onto adjacent transverse processes. The inner side of the fusion device body is a biomimetic irregular curved surface 10 adapted to fit the outer side of the articular process. The fusion device body includes a metal three-dimensional frame 1 and a porous filling part 2. The porous filling part 2 is disposed in the metal three-dimensional frame 1 so that the fusion device body has an overall elongated structure. The metal three-dimensional frame 1 is exposed at each edge of the outer surface of the fusion device body. The middle part of the porous filling part 2 also has a bone graft material filling cavity 3. The pores of the porous filling part 2 are configured to load osteogenic growth factors, drugs or stem cells.

[0024] The beneficial effects of the bionic lumbar intertransverse process fusion device and its manufacturing method in this embodiment are as follows: By setting mounting parts at both ends of the fusion device body, it can be detachably assembled onto adjacent transverse processes, thereby providing stable mechanical anchoring for the bone graft area. The implanted bone material is thus constrained within the predetermined bone graft bed range between the transverse processes, effectively resisting the tension and compression of paravertebral muscles and soft tissues after surgery, and resisting the shear stress generated by physiological activities such as spinal flexion, extension, and rotation. This significantly reduces the risk of bone graft material displacement and provides a basic guarantee for the stability of bone grafts between transverse processes. The biomimetic irregular curved surface 10 on the inner side of the fusion device body is designed to fit the outer side of the articular process, so that the fusion device can closely match the local anatomical shape of the posterolateral lumbar spine, increasing the contact area between the fusion device and the autologous bone surface. This facilitates the uniform transmission of stress between the fusion device and the host bone, avoids bone resorption or implant loosening caused by local stress concentration, and reduces the ineffective gap between the bone graft area and the surrounding soft tissue. This further restricts the bone graft particles from escaping outward or shifting inward, creating a stable local mechanical environment for bone graft fusion. The metal three-dimensional frame 1 is exposed at each edge of the outer surface, forming a load-bearing skeleton, which ensures that the fusion device has sufficient compressive and bending strength when bearing spinal loads, and avoids the implant from collapsing or breaking under long-term physiological load; while the porous filling part 2 provides a three-dimensional through porous structure for bone tissue ingrowth, which is conducive to the inward crawling and ingrowth of host bone, realizing the bio-integration of the fusion device and autologous bone. Furthermore, the bone graft material filling cavity 3 set in the middle of the porous filling part 2 provides a concentrated space for autologous bone or allogeneic bone particles. Compared with the traditional scattered bone grafting method, this cavity structure allows the bone graft material to be concentrated in the core position of the fusion area, improving the local bone graft density and osteogenic efficiency. At the same time, the pores of the porous filling part 2 also have the ability to load osteogenic growth factors, drugs or stem cells. In the early postoperative period, it can exert the biological functions of actively inducing osteoogenesis, anti-inflammation or promoting angiogenesis through local sustained release effect. Thus, active biological stimulation is superimposed on the basis of dynamic fixation, and the process of intertransverse bony fusion is synergistically promoted. In summary, this fusion device systematically solves the problems of easy displacement of bone graft materials, unstable fusion environment, and insufficient osteogenic activity in traditional PLF procedures through the multi-level structural synergy of "mechanical fixation at both ends, anatomical fit achieved by biomimetic curved surface, structural strength guaranteed by three-dimensional frame, bone ingrowth supported by two porous filling parts, concentrated bone graft material contained in the bone graft filling cavity, and active factors loaded in the pores to synergistically induce osteoogenesis". This helps to improve the success rate of intertransverse process bone graft fusion, reduce the risk of postoperative pseudoarthrosis, and improve the long-term clinical efficacy of posterolateral spinal fusion.

[0025] In this embodiment, the mounting part is fixed by screws and includes two bone graft screws 4. The two ends of the fusion device body are provided with perforations. The bone graft screws 4 pass through the perforations and are threaded into the transverse protrusion.

[0026] During the surgical procedure, the fusion cage body is first placed in the predetermined intertransverse process position, with the two perforations aligned with the predetermined entry points on the adjacent transverse processes. Then, the bone graft screws 4 are passed through the perforations and screwed into the transverse process bone. The threads of the bone graft screws 4 form a mechanical interlock with the cortical and cancellous bone of the transverse process, thereby anchoring both ends of the fusion cage body to the adjacent transverse processes. Through this screw fixation method, the fusion cage body obtains reliable rigid constraint in the intertransverse process region, effectively resisting the traction and compression of the fusion cage by the paravertebral muscles and soft tissues after surgery. It also resists the multi-directional shear stress generated during spinal flexion, extension, and rotation, preventing displacement or loosening of the fusion cage body and providing continuous mechanical stability for bone graft fusion.

[0027] The metal three-dimensional frame 1 has metal sleeves 5 fixed inside both ends, and perforations are formed in the metal sleeves 5. The metal sleeves 5 have grooves for the caps of the bone graft screws 4 to be accommodated.

[0028] When the bone graft screw 4 passes through the perforation in the metal sleeve 5, the screw head falls precisely into the recess. The inner wall of the recess provides radial constraint to the screw head, preventing the screw from swinging under stress. Simultaneously, the bottom surface of the recess can withstand the axial clamping force applied during screw tightening, ensuring that stress is evenly transmitted to the metal frame 1 via the metal sleeve 5, rather than concentrating at a localized point. This avoids the risk of fatigue cracks in the frame structure due to stress concentration. Furthermore, the metal sleeve 5 isolates the screw from the porous filling 2, preventing compression damage to the porous structure during screw insertion and ensuring the integrity and functional stability of the porous structure during surgical procedures.

[0029] Furthermore, the metal three-dimensional frame 1 and the two metal sleeves 5 are both made of titanium metal or titanium alloy and are welded and fixed. The porous filling part 2 is integrally solidified in the metal three-dimensional frame 1 by biodegradable magnesium alloy or polylactic acid-hydroxyapatite composite material through 3D printing technology.

[0030] Titanium metal or titanium alloy possesses excellent mechanical strength and biocompatibility. A three-dimensional metal frame 1 and two metal sleeves 5, made from titanium, are welded together to form an integral skeleton. This ensures that the entire fusion device possesses sufficient compressive, bending, and fatigue strength to withstand spinal loads, preventing fracture or plastic deformation during long-term in vivo service. The porous filling part 2, composed of biodegradable magnesium alloy or polylactic acid-hydroxyapatite composite material, provides a stable three-dimensional porous scaffold structure in the early stages of implantation, guiding host bone tissue ingrowth. As bone healing progresses, this biodegradable material gradually degrades in vivo, with its degradation products being metabolized and absorbed by the body. Simultaneously, newly formed bone tissue gradually replaces the space occupied by the filling part, ultimately achieving complete osseointegration between the fusion device and the host bone, avoiding the long-term potential risks associated with permanent implant residue.

[0031] In this embodiment, the bone graft material filling cavity 3 is a single rectangular through hole, and the inner wall of the bone graft material filling cavity 3 is provided with a rough surface or microporous structure to increase the bonding force with the bone graft material.

[0032] During the surgery, after autologous bone or allogeneic bone particles are compacted and filled into the rectangular opening, the rough surface or microporous structure of the cavity wall significantly increases the coefficient of friction and mechanical interlocking between the bone graft material and the cavity wall. When spinal movement or muscle contraction generates vibration or shear force, this binding force effectively resists the bone graft material from dislodging from the cavity or causing micromovement, keeping the bone graft material always confined to the core position of the fusion area, continuously exerting its osteogenic induction effect, and improving the utilization efficiency of the bone graft material.

[0033] In this embodiment, the width of the fusion body gradually decreases from the middle towards both ends, the length of the fusion body is 28-36mm, the width of the fusion body is 8-15mm, and the thickness of the fusion body is 5-10mm.

[0034] In terms of structural dimensions, this widened design allows the narrower ends of the fusion device, after installation in the intertransverse region, to better adapt to the gradually narrowing anatomical shape of the transverse root, while the wider middle section corresponds to the core area of ​​bone graft fusion, accommodating more bone graft material within a limited space. The specific dimensional ranges for length, width, and thickness mentioned above were determined based on anatomical measurements of the intertransverse region of the lumbar vertebrae, ensuring good anatomical fit of the fusion device in the vast majority of patients and avoiding problems such as implantation difficulties, excessive tissue traction, or insufficient fusion area due to improper dimensional changes.

[0035] Preferably, the porosity of the porous filling part 2 is 50% to 80% and the pore size is 100 to 600 μm.

[0036] This porosity range ensures sufficient three-dimensional interconnected space within the filling region, providing pathways for the ingrowth of new bone tissue while maintaining adequate solid wall thickness to preserve the mechanical stability of the scaffold structure. This avoids scaffold collapse due to excessive porosity or bone ingrowth being hindered by insufficient porosity. Furthermore, controlling the pore size within the range of 100–600 μm is, on the one hand, greater than the minimum pore size threshold required for cell migration, facilitating the migration and proliferation of osteoblasts, mesenchymal stem cells, and vascular endothelial cells into the filling region; on the other hand, this pore size range provides suitable physical space for angiogenesis, ensuring adequate nutrient supply and metabolic waste removal pathways for the ingrowth tissue, thereby accelerating the bone integration process.

[0037] More preferably, the porosity of the porous filling part 2 is 60% to 75% and the pore size is 200 to 400 μm.

[0038] Within this preferred parameter range, the combination of porosity and pore size achieves an optimal balance between mechanical support and biological induction. Experimental studies have shown that a pore size of 200–400 μm is most conducive to the physiological remodeling of osteoids, allowing newly formed bone tissue to form a structural arrangement similar to that of natural bone tissue. Meanwhile, a porosity of 60%–75% maximizes the specific surface area of ​​the filling portion under this pore size combination, providing sufficient attachment sites for subsequently loaded osteogenic growth factors or drugs. At the same time, it ensures that the scaffold degradation rate matches the ingrowth rate of new bone tissue, avoiding premature loss of mechanical support due to excessively rapid degradation or hindering the bone replacement process due to excessively slow degradation.

[0039] Reference Figure 1-4Embodiment 1 of this application also provides a method for manufacturing the bionic lumbar intertransverse process fusion device as described above, comprising the following steps: S1: Based on the patient's lumbar spine CT or MRI image data, reconstruct a three-dimensional model of the lumbar spine and obtain the anatomical morphological parameters of the transverse process; S2: Based on the anatomical morphological parameters of the transverse process, design a three-dimensional model of the fusion device body and the mounting part, wherein the inner side of the fusion device body is a biomimetic irregular curved surface 10, and the fusion device body includes a metal three-dimensional frame 1 and a porous filling part 2. S3: First, a three-dimensional metal frame 1 is formed by welding titanium metal or titanium alloy. Then, a biodegradable magnesium alloy or polylactic acid-hydroxyapatite composite material is integrally solidified in the three-dimensional metal frame 1 using 3D printing technology to obtain a fusion device body with a long strip structure and a bone graft material filling cavity 3. S4: Perform the following surface treatments on the fusion unit body: sandblasting, acid etching, anodizing, or coating. S5: Load osteogenic growth factors, drugs, or stem cells into the pores of the fusion device body. The method for loading growth factors or drugs is physical adsorption, impregnation, microsphere embedding, or layer-by-layer self-assembly. The method for loading stem cells is direct seeding or hydrogel embedding.

[0040] By reconstructing a three-dimensional model using individualized CT or MRI image data of the patient, the final fusion device is highly matched to the patient's own intertransverse process anatomy in terms of size and surface morphology, achieving a truly personalized biomimetic fit. Based on this model, a three-dimensional metal frame 1 is designed and formed by welding titanium alloy, ensuring the basic mechanical properties of the implantable component. Subsequently, biodegradable material is integrally solidified into the interior of the three-dimensional metal frame 1 using 3D printing technology. This process ensures the interfacial bonding strength between the three-dimensional metal frame 1 and the porous filling part 2, effectively eliminating the interface micro-movement and gap problems that may be caused by the separate assembly method.

[0041] Surface treatment steps improve the microstructure and chemical properties of the fusion device surface, enhancing its hydrophilicity and protein adsorption capacity, which is beneficial for the adhesion and spread of host osteocytes on the fusion device surface after implantation. In the final step of loading active factors, physical adsorption and impregnation methods are simple to operate and can maintain factor activity, while microsphere embedding and layer-by-layer self-assembly methods can achieve sustained and controlled release of factors. Direct seeding and hydrogel embedding methods can deliver live cells into the fusion device. Various methods can be selected according to clinical needs, collectively endowing the fusion device with the biological function of actively inducing osteogenic processes.

[0042] Example 2 This embodiment also provides a biomimetic lumbar intertransverse process fusion device, as shown in the reference. Figure 5The difference from Embodiment 1 is that the mounting part is fixed by hook fixing and includes two locking hooks 6. The two locking hooks 6 are respectively hinged to both ends of the metal three-dimensional frame 1. The outer surface and hook tip of the locking hook 6 are both set as arc transition structure.

[0043] In this hook fixation method, during surgery, the locking hook 6 is rotated around the hinge axis to a suitable angle and hooks onto the edge of the adjacent transverse process or the attachment point of the intertransverse ligament, thereby locking the position of the fusion device body relative to the transverse process. The hinge structure allows the hook to adjust its hooking direction and angle according to the actual anatomical situation during surgery, reducing the requirements for implantation precision and improving the convenience and fault tolerance of the surgical operation. The outer surface and hook tip of the locking hook 6 both adopt a rounded transition structure, effectively avoiding cutting and friction damage to surrounding soft tissues (such as paraspinal muscles, blood vessels, nerve roots, etc.) from sharp edges. At the same time, the rounded structure is less prone to stress concentration mechanically, reducing the risk of fatigue fracture of the hook under long-term cyclic load.

[0044] Example 3 This embodiment also provides a biomimetic lumbar intertransverse process fusion device, as shown in the reference. Figure 6 The difference from Embodiment 1 is that the bone graft material filling cavity 3 is a plurality of spaced circular cylindrical holes. In other embodiments, the bone graft material filling cavity 3 may also be a single elliptical through hole or a single oval through hole.

[0045] The multiple spaced-apart circular bore structure, while ensuring the total amount of bone graft material can be accommodated, increases the structural rigidity of the fusion device itself through the spacer walls between the bores. This allows the load to be effectively transferred to the metal three-dimensional frame 1 when the fusion device is subjected to spinal compression loads, rather than being entirely borne by the bone graft material alone. Simultaneously, each circular bore independently accommodates bone graft particles, and the bore walls provide separation and constraint for the bone graft material. When the bone graft material in one bore changes due to local micro-movement, the bone graft material in adjacent bores remains unaffected, reducing the risk of diffusion of fusion failure across the entire bone graft area. If a single elliptical or oval through-hole is used, its smooth channel contour facilitates the uniform filling and compaction of the bone graft material. The absence of sharp corners prevents loose filling or dead spaces at the corners of the channel, ensuring the uniformity of bone graft density throughout the entire bone graft material filling cavity 3.

[0046] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A biomimetic intertransverse process fusion device for lumbar vertebrae, characterized in that, Includes a fusion body, with mounting portions at both ends of the fusion body, the two mounting portions being detachably mounted on adjacent transverse processes respectively, and the inner surface of the fusion body being a biomimetic irregular curved surface adapted to fit the outer side of the articular processes (10); The fusion device body includes a metal three-dimensional frame (1) and a porous filling part (2). The porous filling part (2) is disposed in the metal three-dimensional frame (1) so that the fusion device body as a whole has an elongated structure. The metal three-dimensional frame (1) is exposed at each edge of the outer surface of the fusion device body. The middle part of the porous filling part (2) also has a bone graft material filling cavity (3). The pores of the porous filling part (2) are configured to load osteogenic growth factors, drugs or stem cells.

2. The biomimetic lumbar intertransverse process fusion device according to claim 1, characterized in that, The mounting part is fixed by screws and includes two bone graft screws (4). The two ends of the fusion device body are provided with perforations. The bone graft screws (4) pass through the perforations and are threaded into the transverse process.

3. The biomimetic lumbar intertransverse process fusion device according to claim 2, characterized in that, Metal sleeves (5) are fixed inside both ends of the metal three-dimensional frame (1). The perforation is formed in the metal sleeve (5). The metal sleeve (5) has a groove for the cap of the bone graft screw (4) to be received.

4. The biomimetic intertransverse process fusion device for lumbar vertebrae according to claim 3, characterized in that, The metal three-dimensional frame (1) and the two metal sleeves (5) are both made of titanium metal or titanium alloy and are welded and fixed. The porous filling part (2) is integrally solidified in the metal three-dimensional frame (1) by 3D printing technology using biodegradable magnesium alloy or polylactic acid-hydroxyapatite composite material.

5. The biomimetic lumbar intertransverse process fusion device according to claim 1, characterized in that, The mounting part is fixed by hook fixing and includes two locking hooks (6). The two locking hooks (6) are respectively hinged to both ends of the metal three-dimensional frame (1). The outer surface and hook tip of the locking hook (6) are both set as arc transition structure.

6. The biomimetic intertransverse process fusion device for lumbar vertebrae according to claim 1, characterized in that, The bone graft material filling cavity (3) is a plurality of spaced circular holes, a single elliptical through hole, a single rectangular through hole or a single oval through hole. The inner wall of the bone graft material filling cavity (3) is provided with a rough surface or a microporous structure to increase the bonding force with the bone graft material.

7. The biomimetic intertransverse process fusion device for lumbar vertebrae according to claim 1, characterized in that, The width of the fusion device body gradually decreases from the middle towards both ends. The length of the fusion device body is 28-36mm, the width of the fusion device body is 8-15mm, and the thickness of the fusion device body is 5-10mm.

8. The biomimetic intertransverse process fusion device for lumbar vertebrae according to claim 1, characterized in that, The porosity of the porous filling part (2) is 50% to 80% and the pore size is 100 to 600 μm.

9. The biomimetic intertransverse fusion device for lumbar vertebrae according to claim 1, characterized in that, The porous filling part (2) has a porosity of 60% to 75% and a pore size of 200 to 400 μm.

10. A method for manufacturing a biomimetic intertransverse process fusion device for lumbar vertebrae as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Based on the patient's lumbar spine CT or MRI image data, a three-dimensional model of the lumbar spine is reconstructed to obtain the anatomical morphological parameters of the transverse process. The three-dimensional model of the fusion device body and the mounting part is designed based on the anatomical morphological parameters of the transverse process. The inner side of the fusion device body is a biomimetic irregular curved surface (10). The fusion device body includes a metal three-dimensional frame (1) and a porous filling part (2). First, a three-dimensional metal frame (1) is formed by welding titanium metal or titanium alloy. Then, a biodegradable magnesium alloy or polylactic acid-hydroxyapatite composite material is integrally solidified in the three-dimensional metal frame (1) by 3D printing technology to obtain a fusion device body with a long strip structure and a bone graft material filling cavity (3). The fusion unit body undergoes the following surface treatments: sandblasting, acid etching, anodizing, or coating. Osteogenesis-promoting growth factors, drugs, or stem cells are loaded into the pores of the fusion device body. The methods for loading growth factors or drugs include physical adsorption, impregnation, microsphere embedding, or layer-by-layer self-assembly. The methods for loading stem cells include direct seeding or hydrogel embedding.

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