A biodegradable spinal cage with osteoinductive microporous structure

Abstract

The application discloses a degradable spinal fusion cage with a bone inductive microporous structure and belongs to the technical field of orthopedic implant medical devices. The fusion cage is integrally made of a degradable polymer composite material, the inside of the main body is provided with a bionic gradient microporous structure which is interconnected, and the surface of the fusion cage is provided with an active coating layer with a slow-release function. The mechanical property of the product is adapted to the physiological bearing requirement of the spine, the product can be steadily degraded along with the bone tissue regeneration process after being implanted into the human body, can effectively guide the bone tissue and microvessels to grow in, and can improve the intervertebral fusion efficiency; meanwhile, the problems of stress shielding, postoperative infection and the need for secondary removal surgery existing in traditional metal implants are solved, the product has good biocompatibility, the structure is reasonable, the preparation process is simple, and the product is suitable for clinical intervertebral fusion surgery of the spine.

Description

Technical Field

[0001] This invention relates to the field of orthopedic implant medical device technology, specifically to a biodegradable spinal fusion device with a bone-inducing microporous structure. Background Technology

[0002] Spinal interbody fusion surgery is a common procedure used in clinical practice to treat conditions such as lumbar disc herniation, lumbar spondylolisthesis, spinal instability, and degenerative spinal diseases. The spinal fusion device is an indispensable core implantable device in this surgery. Currently, most spinal fusion devices used in clinical practice are made of metal materials such as titanium alloys. These metal fusion devices have high overall rigidity and are prone to stress shielding effects, which can inhibit the growth and remodeling of autologous bone to a certain extent, and easily lead to postoperative complications such as slow bone healing and nonunion. At the same time, the metal material cannot be absorbed by the human body, and patients often need to undergo a second surgery to remove the implant after surgery, which not only increases surgical trauma, but also increases the economic cost of treatment for patients and the risk of postoperative infection. Existing biodegradable fusion device products generally suffer from problems such as poor pore structure connectivity, weak bone induction ability, and poor antibacterial effect. Postoperative complications such as implantation site infection and fusion device displacement and subsidence are common. There is still considerable room for improvement in the overall user experience and clinical treatment effect. Summary of the Invention

[0003] Technical solution The purpose of this invention is to overcome the shortcomings of the prior art and provide a biodegradable spinal fusion device with a bone-inducing microporous structure, which combines good mechanical support performance, bone-inducing growth performance and biodegradability. This fusion device is made of a biodegradable material composed of polylactic acid and hydroxyapatite. The material itself has excellent biocompatibility and will not cause rejection after implantation into the human body. Through additive manufacturing, an interconnected gradient biomimetic microporous structure is formed inside the main body of the fusion device. This structure can provide sufficient growth space for bone tissue adhesion and new blood vessel growth, effectively improve bone conduction and bone induction capacity, and accelerate the overall process of intervertebral bony fusion. The outer surface of the fusion device is equipped with an integrated active sustained-release coating, which can slowly release antibacterial and osteoinductive active ingredients, effectively reducing the probability of postoperative wound infection and further promoting rapid bone tissue healing. The fusion device is a one-piece molded structure with stable and reliable structure. The anti-slip texture on the upper and lower surfaces and the hollow channel design in the middle can effectively improve the fit and structural stability after implantation. After the fusion device is implanted in the human body, it will gradually degrade and be synchronous with the bone tissue as it regenerates. The degradation products are safe and non-toxic and can be absorbed by the human body through normal metabolism. Once the intervertebral bone fusion is completed, the implant will be almost completely degraded, eliminating the need for a second removal surgery and greatly reducing the patient's surgical pain and treatment burden. Beneficial effects Adopting a biomimetic gradient interconnected microporous structure design, it has excellent bone conduction and bone induction effects, which can effectively guide the ingrowth of bone tissue and microvessels, and significantly accelerate the speed of intervertebral bone fusion. The implant is fully biodegradable, eliminating the need for a second surgery to remove it, reducing surgical trauma, and lowering the risk of postoperative infection and overall treatment costs for patients. The surfactant sustained-release coating has both antibacterial and bone-growth-promoting effects, which can effectively inhibit bacterial growth, improve the postoperative healing environment, and increase the overall success rate of surgery. The overall mechanical properties are balanced and reasonable, avoiding the stress shielding problem of traditional metal implants, and are more in line with the normal biomechanical movement of the human spine. The material has excellent biocompatibility, and there is no obvious inflammatory reaction or release of toxic or harmful substances after implantation, making it safer for implantation. The one-piece molding structure is simple and regular, the manufacturing process is mature and convenient, and it has strong clinical adaptability. It can be widely used in multi-segment spinal interbody fusion surgery and has broad clinical application prospects. Detailed Implementation Polylactic acid raw material and nano-hydroxyapatite powder are uniformly mixed in an appropriate ratio to prepare a uniform and stable biodegradable composite substrate. The main body of the fusion device is prepared by selective laser sintering using appropriate additive manufacturing equipment. During the forming process, the internal gradient interconnected microporous structure, external anti-slip texture and central hollow through channel are simultaneously processed. Subsequently, a mild composite process was used to prepare an active sustained-release coating with both antibacterial and bone-inducing effects on the outer surface of the fusion device body, ensuring that the coating is firmly bonded to the substrate and that the release rate is slow and stable. After preparation, the finished product was tested for mechanical properties, biocompatibility, and degradation performance. After all indicators passed the tests, it was sterilized with ethylene oxide and aseptically packaged to finally obtain the finished spinal fusion device. When performing spinal interbody fusion surgery in clinical practice, this fusion device is simply implanted into the pre-set position in the intervertebral space. After the surgery, the coating slowly releases effective active ingredients, and the microporous structure guides bone tissue to grow in gradually. The fusion device degrades slowly as the bone heals, and finally, the autologous bone completes the permanent intervertebral fusion. The fusion device is then naturally metabolized and absorbed by the body.

Claims

1. A biodegradable spinal fusion device with a bone-inducing microporous structure, comprising a fusion device body, characterized in that: The fusion device body is integrally molded from a biodegradable composite polymer material. The interior of the fusion device body is provided with an interconnected gradient microporous structure, and the outer surface of the fusion device body is coated with an active sustained-release coating. The fusion device body has mechanical strength adapted to the stress on the spine and can be gradually degraded and absorbed after implantation into the human body.

2. The biodegradable spinal fusion device with a bone-inducing microporous structure according to claim 1, characterized in that: The biodegradable composite polymer material includes polylactic acid matrix and hydroxyapatite powder, which are uniformly blended to form a stable matrix system.

3. The biodegradable spinal fusion device with a bone-inducing microporous structure according to claim 1, characterized in that: The gradient microporous structure contains multi-level pores with different pore sizes that are interconnected. The pore structure is continuous and allows human bone tissue, new blood vessels, and body fluids to permeate and grow.

4. A biodegradable spinal fusion device with a bone-inducing microporous structure according to claim 1, characterized in that: The active sustained-release coating contains antibacterial components and osteoinductive active components. The coating can slowly and continuously release effective ingredients after implantation, thereby inhibiting bacterial growth in the wound and promoting bone cell proliferation and growth.

5. A biodegradable spinal fusion device with a bone-inducing microporous structure according to claim 1, characterized in that: The upper and lower contact surfaces of the fusion device body are provided with anti-slip textured structures, and a hollow through channel is provided in the middle of the fusion device body to improve the overall structural stability and reduce the probability of vertebral body subsidence and micro-movement after implantation.

6. A biodegradable spinal fusion device with a bone-inducing microporous structure according to claim 1, characterized in that: The fusion device is integrally printed using additive manufacturing technology, resulting in a complete one-piece structure without any splicing or assembly. After implantation into the human body, its degradation products are safe and non-irritating, and can ultimately be naturally metabolized and absorbed by the human body.