3D printing height-adjustable spinal tumor integrated reconstruction prosthesis

Abstract

This invention provides a 3D-printed, height-adjustable integrated reconstruction prosthesis for spinal tumors, belonging to the field of orthopedic medical device technology. It includes a support frame with two first prostheses symmetrically fixedly connected to its top and bottom. Each first prosthesis has a hollow internal structure. An adjusting ring is rotatably connected to the inner wall of the support frame, and an adjusting threaded rod is fixedly connected to the inner wall of the adjusting ring. The adjusting threaded rod is rotatably connected to the interior of the first prosthesis. A second prosthesis is threadedly connected to the outer wall of the adjusting threaded rod, and the second prosthesis is slidably connected to the inner wall of the first prosthesis. The support frame, first prosthesis, and second prosthesis are formed by 3D printing. The prosthesis as a whole is a porous titanium alloy structure with a porosity of 60%–80% and a pore size of 300μm–800μm. This invention has the advantages of strong adaptability, high surgical efficiency, structural stability, few complications, good biocompatibility, high safety, individualized customization, and strong clinical adaptability.

Description

Technical Field

[0001] This invention relates to the field of orthopedic medical device technology, and in particular to a 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis. Background Technology

[0002] Spinal tumors are common malignant or benign lesions in orthopedics. Clinical treatment primarily involves complete tumor resection combined with prosthetic reconstruction, with the core objective being to restore spinal stability and reduce postoperative complications. Currently used spinal tumor reconstruction prostheses have the following problems: 1. Fixed height and poor adaptability: Most existing prostheses are of fixed height specifications. The height of bone defects after spinal tumor resection varies greatly among different patients. Different sizes of prostheses need to be changed repeatedly during the operation, which not only prolongs the operation time (an average increase of 30-60 minutes), but also easily leads to prosthesis displacement and sinking due to insufficient matching accuracy. 2. Weak bone ingrowth: Traditional prostheses often have smooth surfaces or unreasonable porosity and pore size, making it difficult for bone tissue to ingrow in. This results in a low rate of fusion between the prosthesis and the vertebral body after surgery, and complications such as loosening and dislocation are prone to occur, with an incidence rate as high as 15%–20%. 3. Insufficient structural stability: Some prostheses use a spliced ​​structure, which is complicated to assemble during surgery and is prone to loosening and breakage at the splice points after surgery, affecting the stability of the spine; To address this, a 3D-printed, height-adjustable integrated spinal tumor reconstruction prosthesis is proposed. Summary of the Invention

[0003] In view of this, the present invention provides a 3D-printed height-adjustable integrated reconstructive prosthesis for spinal tumors to solve or alleviate one of the technical problems existing in the prior art, and at least provides a beneficial alternative.

[0004] The technical solution of this invention is implemented as follows: a 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis includes a scaffold. Two first prostheses are symmetrically fixedly connected to the top and bottom of the scaffold. The first prosthesis has an internal hollow structure. An adjustment ring is rotatably connected to the inner wall of the scaffold. An adjustment threaded rod is fixedly connected to the inner wall of the adjustment ring. The adjustment threaded rod is rotatably connected to the inside of the first prosthesis. A second prosthesis is threadedly connected to the outer wall of the adjustment threaded rod. The second prosthesis is slidably connected to the inner wall of the first prosthesis. The scaffold, the first prosthesis, and the second prosthesis are formed by 3D printing. The prosthesis as a whole has a porous titanium alloy structure with a porosity of 60%–80% and a pore size of 300μm–800μm.

[0005] The prosthesis consists of three parts: a central support, two end prostheses, and an internal second prosthesis 18. This design ensures overall stability after implantation while allowing for highly precise fine-tuning through internal mechanical adjustment structures. Compared to traditional fixed-size vertebral replacement prostheses, this design can more accurately match the individualized vertebral defect height resulting from tumor resection.

[0006] A further preferred embodiment: the outer wall of the adjusting ring is provided with anti-slip texture, and the anti-slip texture 14 is provided on the adjusting ring to increase friction and ensure that the doctor can rotate the adjusting ring stably and accurately when operating while wearing gloves.

[0007] A further preferred embodiment: two guide rods are symmetrically fixedly connected to the inner sidewall of the first prosthesis, and a limit block is fixedly connected to the top of the guide rod. The two symmetrical guide rods cooperate with the limit sliding sleeve to ensure the parallel fit between the upper and lower endplates of the prosthesis and the vertebral endplate.

[0008] A further preferred embodiment has a groove at the top of the second prosthesis.

[0009] A further preferred embodiment has screw fixing holes evenly distributed on the top of the second prosthesis. These screw fixing holes allow the surgeon to fix the prosthesis to the adjacent vertebrae using vertebral screws after the prosthesis has been implanted and adjusted to a suitable height.

[0010] A further preferred embodiment: the bottom of the second prosthesis is symmetrically provided with limiting sleeves, and the guide rod is slidably connected to the inner sidewall of the limiting sleeve.

[0011] A further preferred embodiment has a threaded hole at the bottom of the second prosthesis.

[0012] Further preferred: The prosthesis material is medical-grade Ti6Al4V titanium alloy, with an elastic modulus of 15–30 GPa, compressive strength ≥300 MPa, and the surface is anodized with an oxide layer thickness of 5 μm–10 μm. Medical-grade Ti6Al4V titanium alloy has excellent biocompatibility, high specific strength and excellent corrosion resistance. The titanium oxide film can not only further improve corrosion resistance, but also change the surface color by controlling the oxide layer thickness.

[0013] Further preferred embodiment: The surface of the prosthesis can be coated with an anti-infection and osteogenic bioactive coating with a thickness of 10μm–20μm. The coating material is a composite system of hydroxyapatite and gentamicin. Hydroxyapatite is the main inorganic component of human bone. The coating will slowly dissolve in the body, releasing calcium ions and phosphorus ions, inducing the differentiation of host mesenchymal stem cells into osteoblasts, accelerating bone integration, and shortening the rehabilitation period. By coating the surface of the prosthesis with a gentamicin-containing coating, local drug sustained release is achieved.

[0014] Further preferred: The prosthesis is individually 3D printed based on the patient's CT data. The 3D printing process is laser selective melting molding, with a printing accuracy of ±0.1mm. It is suitable for bone defect reconstruction after thoracic and lumbar spine tumor resection. The use of laser selective melting molding technology allows the integrated complex structure to be formed in one go without welding or assembly.

[0015] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions: I. High adaptability and high surgical efficiency: It can be continuously adjusted during the operation, without the need to repeatedly change the prosthesis model, which greatly shortens the operation time, reduces the surgical risk, and adapts to the bone defect height of different patients and the growth needs of children and adolescents. II. Stable structure and fewer complications: The integrated 3D printed structure has no splicing gaps, high strength and good stability. The porous structure design promotes bone tissue ingrowth, improves the fusion rate, and reduces the incidence of complications to below 5%. III. Good biocompatibility and high safety: It adopts medical-grade Ti6Al4V titanium alloy, with an elastic modulus close to that of the human vertebral body, reducing stress shielding. The surface anodizing treatment and optional drug-loaded coating further improve biocompatibility and clinical efficacy. IV. Personalized customization and strong clinical adaptability: Based on the patient's CT data, it is precisely printed to perfectly fit the shape of the bone defect, solving the problem of poor adaptability of traditional prostheses.

[0016] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced 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 structural diagram of the present invention; Figure 2 This is a structural diagram of the first and second prostheses of the present invention after disassembly; Figure 3 This is a structural diagram of the second prosthesis of the present invention; Figure 4 This is a structural diagram of the first prosthesis of the present invention.

[0019] Reference numerals: 11. Bracket; 12. First prosthesis; 13. Adjusting ring; 14. Anti-slip texture; 15. Adjusting threaded rod; 16. Guide rod; 17. Limiting block; 18. Second prosthesis; 19. Groove; 20. Screw fixing hole; 21. Limiting slide sleeve; 22. Threaded hole. Detailed Implementation

[0020] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0021] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] like Figures 1-4 As shown, this embodiment of the invention provides a 3D-printed height-adjustable integrated reconstruction prosthesis for spinal tumors, including a support 11. Two first prostheses 12 are symmetrically fixedly connected to the top and bottom of the support 11. The first prosthesis 12 has an internal hollow structure. An adjustment ring 13 is rotatably connected to the inner wall of the support 11. An adjustment threaded rod 15 is fixedly connected to the inner wall of the adjustment ring 13. The adjustment threaded rod 15 is rotatably connected to the inside of the first prosthesis 12. A second prosthesis 18 is threadedly connected to the outer wall of the adjustment threaded rod 15. The second prosthesis 18 is slidably connected to the inner wall of the first prosthesis 12. The support 11, the first prosthesis 12, and the second prosthesis 18 are formed by 3D printing. The entire prosthesis is a porous titanium alloy structure with a porosity of 60%–80% and a pore size of 300μm–800μm.

[0023] The prosthesis consists of three parts: a central support 11, two end prostheses 12 (fixed ends), and an internal second prosthesis 18 (movable end). This design ensures the overall stability of the prosthesis after implantation and allows for highly precise adjustment through internal mechanical adjustment structures. Compared to traditional fixed-size vertebral body replacement prostheses, this design can more accurately match the individualized vertebral defect height resulting from tumor resection.

[0024] Since the second prosthesis 18 is restricted in its circumferential rotation by the guide rod 16, the rotational motion of the threaded rod is converted into the linear extension and retraction motion of the second prosthesis 18 relative to the first prosthesis 12.

[0025] In this embodiment, specifically: the outer wall of the adjustment ring 13 is provided with anti-slip texture 14. Spinal surgery spaces are confined and often contain blood and tissue fluid. The anti-slip texture 14 on the adjustment ring 13 increases friction, ensuring that the surgeon can rotate the adjustment ring stably and accurately while wearing gloves, avoiding adjustment errors or tissue damage caused by slippage.

[0026] In this embodiment, specifically: two guide rods 16 are symmetrically fixedly connected to the inner sidewall of the first prosthesis 12, and a limiting block 17 is fixedly connected to the top of the guide rod 16. The two symmetrical guide rods 16 cooperate with the limiting sleeve 21 to form a precision sliding pair, which ensures that the second prosthesis 18 will not sway radially or rotate during the extension and retraction process, and ensures that the upper and lower endplates of the prosthesis are parallel and fit with the vertebral endplate, preventing stress concentration or prosthesis dislodgement caused by misalignment. The limiting block 17 limits the maximum extension length of the second prosthesis 18. If the adjustment is excessive, the limiting block 17 will jam the end face of the limiting sleeve 21 to prevent the second prosthesis 18 from completely dislodging from the first prosthesis 12.

[0027] In this embodiment, specifically: the top of the second prosthesis 18 is provided with a groove 19. The groove 19 increases the accommodating space between the prosthesis end face and the vertebral endplate. On the one hand, the groove 19 can accommodate part of the bone graft material to form a fit; on the other hand, the edge structure of the groove 19 helps to stimulate bone growth under the endplate, promote the fusion of the prosthesis and the host bone, and enhance the initial stability and long-term fusion rate.

[0028] In this embodiment, specifically: the top of the second prosthesis 18 is provided with screw fixing holes 20 evenly distributed. The evenly distributed screw fixing holes 20 allow the doctor to fix the prosthesis to the adjacent vertebrae above and below by means of vertebral screws after the prosthesis is implanted and adjusted to a suitable height.

[0029] In this embodiment, specifically: the bottom of the second prosthesis 18 is symmetrically provided with a limiting sleeve 21, and the guide rod 16 is slidably connected to the inner side wall of the limiting sleeve 21.

[0030] In this embodiment, specifically: the bottom of the second prosthesis 18 is provided with a threaded hole 22, which is used to cooperate with the adjusting threaded rod 15 to complete the adjustment of the overall height of the prosthesis.

[0031] In this embodiment, specifically: the prosthesis material is medical-grade Ti6Al4V titanium alloy with an elastic modulus of 15–30 GPa and a compressive strength ≥300 MPa. The surface is anodized with an oxide layer thickness of 5 μm–10 μm. Medical-grade Ti6Al4V titanium alloy has excellent biocompatibility, high specific strength, and excellent corrosion resistance. The compressive strength ≥300 MPa ensures that the prosthesis can withstand the strong axial load of the spine. A dense titanium oxide film is formed on the surface of the titanium alloy, which not only further improves corrosion resistance but also changes the surface color by controlling the oxide layer thickness. At the same time, the oxide film has micron-level pores, which can serve as an anchoring layer for subsequent bioactive coatings, enhancing the coating adhesion.

[0032] In this embodiment, specifically: the surface of the prosthesis can be coated with an anti-infection, osteogenic bioactive coating with a thickness of 10μm–20μm. The coating material is a composite system of hydroxyapatite and gentamicin. Hydroxyapatite is the main inorganic component of human bone. The coating slowly dissolves in the body, releasing calcium and phosphorus ions, inducing the differentiation of host mesenchymal stem cells into osteoblasts, accelerating bone integration, and shortening the recovery period. Gentamicin is a broad-spectrum antibiotic. By coating the prosthesis surface with gentamicin, local drug sustained release is achieved. Compared with systemic intravenous administration, the local drug concentration is higher and the duration is longer, which can effectively prevent drug-resistant bacterial infections and avoid the hepatotoxicity and nephrotoxicity of systemic antibiotics.

[0033] In this embodiment, specifically: the prosthesis is individually 3D printed based on the patient's CT data. The 3D printing process is laser selective melting molding, with a printing accuracy of ±0.1mm. It is suitable for bone defect reconstruction after thoracic and lumbar spine tumor resection. The use of laser selective melting molding technology allows the integrated complex structure (including internal hollow cavities, threads, guide holes, and porous structures) to be formed in one go without welding or assembly, reducing stress concentration points and weak connection links in traditional processing methods.

[0034] Example 1: Fabrication of a 3D-printed, height-adjustable, integrated spinal tumor reconstruction prosthesis 1. Acquisition and processing of patient image data: CT image data (0.5mm slice thickness) of patients with thoracic spine tumors were acquired. The bone defect model after spinal tumor resection was reconstructed using three-dimensional reconstruction software (such as Mimics). The height of the bone defect was determined to be 22mm, and the width between the upper and lower vertebral bodies was determined to be 38mm.

[0035] Prosthesis Design: Based on the reconstruction model, the overall structure of the prosthesis is designed, and the standard height of the prosthesis is set at 25mm (adjustable range 10mm–40mm). The height of the upper fixation section and the lower support section are both 8mm, and the initial height of the middle height adjustment section is 9mm. The diameter of the pedicle screw fixing hole 20 is 4mm, and the center-to-center distance between the holes is 13mm. The anti-rotation groove is 3mm wide and 5mm deep. The porous structure has a porosity of 70% and a pore diameter of 500μm.

[0036] 3D printing molding: Medical-grade Ti6Al4V titanium alloy powder (particle size 15μm–53μm) is used for integrated printing through a laser selective melting 3D printing equipment (power 300W, scanning speed 1000mm / s, layer thickness 0.03mm). After printing, stress-relief annealing treatment is performed (temperature 700℃, holding for 2h) to remove printing stress.

[0037] Post-processing: The printed prosthesis is ground and polished to remove surface burrs and ensure that there are no sharp edges; the surface of the prosthesis is anodized to form an oxide layer with a thickness of 8μm; finally, it is sterilized and packaged for later use.

[0038] Example 2: Intraoperative use of a 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis 1. Preoperative preparation: The prepared prosthesis is disinfected. The height adjustment section is adjusted in advance according to the actual bone defect height of the patient during the operation. The initial prosthesis height is set to 22mm.

[0039] Prosthesis implantation: After complete resection of the spinal tumor, the prosthesis is placed in the bone defect area, and the position of the prosthesis is adjusted to ensure that the upper fixation segment fits the upper vertebral body and the lower support segment fits the lower vertebral body.

[0040] Fine-tuning of height: By manually rotating the anti-slip knob on the middle height adjustment section, the height of the prosthesis can be finely adjusted to 23mm (adjustment accuracy 1mm / turn) according to the intraoperative fluoroscopy results, to ensure that the prosthesis fits tightly to the vertebral body without gaps.

[0041] Fixation: Pedicle screws are inserted through the pedicle screw fixation hole 20 to firmly fix the prosthesis to the superior and inferior vertebral bodies.

[0042] Postoperative observation: Regular follow-up examinations were conducted after the operation. The porous structure of the prosthesis can promote bone ingrowth. Preliminary bone fusion was achieved 3 months after the operation, and complete bone fusion was achieved 6 months after the operation. There were no complications such as displacement, loosening, or infection.

[0043] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis, including a scaffold (11), characterized in that: The top and bottom of the bracket (11) are symmetrically fixedly connected to two first prostheses (12). The first prosthesis (12) has an internal hollow structure. An adjustment ring (13) is rotatably connected to the inner side wall of the bracket (11). An adjustment threaded rod (15) is fixedly connected to the inner side wall of the adjustment ring (13). The adjustment threaded rod (15) is rotatably connected to the inside of the first prosthesis (12). A second prosthesis (18) is threadedly connected to the outer side wall of the adjustment threaded rod (15). The second prosthesis (18) is slidably connected to the inner side wall of the first prosthesis (12). The bracket (11), the first prosthesis (12) and the second prosthesis (18) are formed by 3D printing. The prosthesis as a whole is a porous titanium alloy structure with a porosity of 60%–80% and a pore size of 300μm–800μm.

2. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The outer wall of the adjusting ring (13) is provided with anti-slip texture (14).

3. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The inner wall of the first prosthesis (12) is symmetrically fixedly connected with two guide rods (16), and the top end of the guide rods (16) is fixedly connected with a limit block (17).

4. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The second prosthesis (18) has a groove (19) at its top.

5. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The top of the second prosthesis (18) is evenly provided with screw fixing holes (20).

6. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The second prosthesis (18) has a symmetrically provided limiting sleeve (21) at the bottom, and the guide rod (16) is slidably connected to the inner side wall of the limiting sleeve (21).

7. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The second prosthesis (18) has a threaded hole (22) at its bottom.

8. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The prosthesis material is medical-grade Ti6Al4V titanium alloy with an elastic modulus of 15–30 GPa, compressive strength ≥300 MPa, and an anodized surface with an oxide layer thickness of 5 μm–10 μm.

9. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The surface of the prosthesis can be coated with a bioactive coating that is anti-infective and promotes bone growth. The coating thickness is 10μm–20μm, and the coating material is a composite system of hydroxyapatite and gentamicin.

10. The 3D-printed height-adjustable integrated spinal tumor reconstruction prosthesis according to claim 1, characterized in that: The prosthesis is individually 3D printed based on the patient's CT data. The 3D printing process is laser selective melting, with a printing accuracy of ±0.1mm, which is suitable for bone defect reconstruction after thoracic and lumbar spine tumor resection.

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