A 3D printed degradable costal cartilage implant

Abstract

A 3D printed degradable chest rib implant comprises a main body and a fixing port arranged on the main body, wherein the curvature of the main body is consistent with the curvature of a rib defect; the main body has a multi-layer structure, the inner layer is a mechanical support-bone fusion structure to provide initial strength required for maintaining the shape of the thoracic structure and respiratory expansion and space for growth of new bone tissue, and the outer layer is a porous structure to facilitate the growth of surrounding soft tissue and later biological fusion fixation; the fixing port on the main body is installed and fixed with a corresponding chest rib combination site; through the regulation of the degradable material components and macro-micro structure, the function of the degradable chest rib implant is programmed to realize the dynamic matching and transformation of mechanical stability and tissue regeneration, with the degradation of the degradable chest rib implant material, the autologous tissue gradually grows into and completely replaces the degradable chest rib implant; the present application can adapt to the repair requirements of congenital chest rib defects in children.

Description

Technical Field

[0001] This invention relates to the fields of tissue engineering, regenerative medicine and medical device technology, and specifically to a 3D-printed biodegradable rib implant. Background Technology

[0002] Rib loss is a congenital chest wall deformity characterized by the partial or complete absence of one or more ribs. The ribs are the main structures of the thoracic cavity, participating in various physiological functions. Rib loss affects the integrity of the thoracic cavity, seriously harming the shape of the spine, respiratory function, and aesthetic appearance, leading to scoliosis, paradoxical breathing, and chest deformities, and in severe cases, even endangering the patient's life.

[0003] Clinically, there are many methods for rib reconstruction, such as autologous / allogeneic bone grafting and repair using materials like steel plates and titanium mesh. However, bone transplantation is limited by the quality of the donor bone. For large-area rib repairs, the availability of donors is limited. Furthermore, good blood supply is a prerequisite for bone graft survival, and the graft must have sufficient fixation to eliminate relative movement and support the ingrowth of new blood vessels. Metallic materials such as steel plates and titanium plates face challenges in shaping and tailoring, their compatibility with the patient depends entirely on the surgeon's feel and experience, and they are difficult to fix and prone to loosening.

[0004] Currently, both domestically and internationally, 3D printing technology and titanium alloy materials have enabled the manufacture of personalized rib cages, successfully repairing chest wall structures. However, the strength of metal prostheses is far greater than that of autologous bone, making it impossible to fully realize the function of the thoracic cavity. Postoperatively, patients experience symptoms such as chest tightness and difficulty breathing. In addition, metal materials also cause difficulties in postoperative imaging examinations.

[0005] In recent years, significant progress has been made in the fabrication of rib and sternal prostheses using PEEK (polyetheretherketone) material. PEEK material has a modulus and strength close to that of bone tissue and exhibits good tissue compatibility. Furthermore, X-rays have good penetration through PEEK, and the reconstruction of the ribs and sternal prostheses does not affect X-ray detection. Existing studies have demonstrated that personalized design and 3D printing of PEEK prostheses have matched the morphology and mechanical properties of natural ribs and costal cartilage, which is beneficial for restoring the respiratory function of the thoracic cavity.

[0006] However, neither non-degradable metals nor PEKK materials can meet the reconstruction needs of children with congenital rib defects. Compared to adults, children's ribs are still in the process of gradual growth and expansion. The fixed-shape metal or PEEK prostheses used to maintain the shape of the chest cavity in the early stages will become new obstacles during the child's growth, seriously affecting the development and growth of the child's chest cavity and its internal vital organs such as the heart and lungs. Therefore, there is an urgent need for a rib implant specifically designed for children with congenital rib defects. Summary of the Invention

[0007] In order to overcome the shortcomings of the prior art, the present invention aims to provide a 3D-printed biodegradable rib implant that can meet the repair requirements of congenital rib defects in children.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] A 3D-printed biodegradable rib implant includes a main body and a fixing port thereon, wherein the curvature of the main body matches the curvature of the rib defect; the main body has a multi-layered structure, with an inner layer being a mechanical support-bone fusion structure to provide space for maintaining the thoracic structure morphology, initial strength required for respiratory expansion, and new bone tissue growth, and an outer layer being a porous structure to facilitate the ingrowth of surrounding soft tissue and subsequent biofusion fixation; the fixing port on the main body is installed and fixed at the corresponding rib junction; by controlling the composition and macro- and micro-structure of the biodegradable material, the function of the biodegradable rib implant is programmed to achieve dynamic matching and transformation between mechanical stability and tissue regeneration, and as the biodegradable rib implant material degrades, autologous tissue gradually grows and infiltrates and completely replaces the biodegradable rib implant.

[0010] The biodegradable rib implant has an inner mechanical support-bone fusion structure that is wrapped in a thin solid layer. The cross-section of the mechanical support-bone fusion structure is a proportionally scaled rib cross-section outline, a variable cross-section, or a circular, elliptical, or I-shaped cross-section. The cross-sectional area accounts for 30-100% of the cross-sectional area of ​​the implant body. Before or during implantation, the implant body has micropores that support bone tissue growth, with a pore size of 100μm to 2mm.

[0011] The porous structure of the outer layer of the biodegradable rib implant body is one or more of the following: through-pores, microrod-based lattice structure, porous structure based on minimal curved surfaces, and gradient structure with variable pore size, with pore size ranging from 500 μm to 2 mm.

[0012] The biodegradable rib implant described herein can be used independently or in combination in practical applications, with its inner mechanical support-bone fusion structure and outer porous structure being used as the main body.

[0013] The biodegradable rib implant is fixed using threaded connections, U-shaped clips on both sides of the corresponding defective rib, or sleeve or burr structures. The fixation ports are on both sides of the main body, or auxiliary fixation clamps are designed in the middle of the main body to fix it to the adjacent ribs. One or more of these fixation methods are selected according to the patient's actual situation. The fixation screws or sutures used in the fixation are made of medical biodegradable materials.

[0014] The materials used to prepare the biodegradable rib implants are medical biodegradable polymer materials, biodegradable ceramic materials, or osteoinductive materials, including one or more of polyhydroxyalkanoates (PHA), polycaprolactone (PCL), polyglycolic acid (PGA), polybutylene succinate (PBS) and its copolymers, polyvinyl alcohol (PVA), polylactic acid (PLA) and polylactic acid-glycolic acid copolymer (PLGA), hydroxyapatite (HA), tricalcium phosphate (TCP), calcium sulfate (CaSO3), and calcium carbonate (CaCO3).

[0015] The biodegradable rib implant is manufactured using 3D printing technology. By coating or doping the surface with functional materials such as gelatin, collagen, functional materials, and growth factors, the biocompatibility, osteoinductive ability, and osteointegration ability of the implant are improved.

[0016] The biodegradable rib implant has a total length of 30-100mm, with the main body accounting for 20-80% of the total length and the fixing port accounting for 80-20% of the total length.

[0017] The main shape of the biodegradable rib implant is obtained by extracting the patient's medical imaging data, mirroring the contralateral healthy rib, or extracting the feature contour from the normal rib. Its thickness can be adjusted to 100-200% of that of the healthy rib.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The biodegradable rib implant of the present invention adopts a multi-layer structure design, which can achieve the matching of mechanical stability and tissue regeneration process. The porous structure of the outer layer of the main body can guide the rapid ingrowth and shaping of autologous soft tissue and vascularized tissue, while the internal mechanical support-bone fusion structure provides strength for the implant as a whole. At the same time, its internal microporous structure supports bone tissue growth, so as to meet the patient's structural and physiological (respiratory) functional needs for thoracic reconstruction.

[0020] 2. The present invention provides a biodegradable rib implant with an inner mechanical support-bone fusion structure and an outer porous structure, which is suitable for the ingrowth of soft and hard tissues. It can then form a good interface fusion and biological fixation, replacing the function of screws and other connectors in the early stage, and effectively solving the problems of rib implant dislodgement and displacement.

[0021] 3. The biodegradable rib implant of the present invention has good biodegradability. As the child grows, the implant material continuously degrades, and autologous tissue can completely replace the implant, ultimately completing the reconstruction and repair of the thoracic cavity. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall and partial aspects of the biodegradable rib implant according to an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the main cross-section of five types of biodegradable rib implants.

[0024] Figure 3 This is a schematic diagram of a cross-section of a biodegradable rib implant based on its material, structure, and function.

[0025] Figure 4 This is a physical image of a 3D-printed biodegradable rib implant according to the present invention.

[0026] Figure 5 This study investigates tissue regeneration within biodegradable rib implants.

[0027] Figure 6 The degradation and mechanical transformation of biodegradable PCL rib implants were investigated. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0029] Reference Figure 1 A 3D-printed biodegradable rib implant includes a main body and a fixing port thereon. The curvature of the main body matches the curvature of the rib defect, allowing it to restore the shape of the thoracic cavity after implantation. The main body has a multi-layered structure: the inner layer is a mechanical support-bone fusion structure to provide initial strength for maintaining the thoracic cavity structure, respiratory expansion, and space for new bone tissue growth; the outer layer is a porous structure to facilitate the ingrowth of surrounding soft tissue and subsequent biofusion fixation. The fixing port on the main body is fixedly installed at the corresponding rib junction. By controlling the composition and macro- and micro-structure of the biodegradable material, the function of the biodegradable rib implant is programmed to achieve dynamic matching and transformation between mechanical stability and tissue regeneration. As the biodegradable rib implant material degrades, autologous tissue gradually grows, infiltrates, and completely replaces the biodegradable rib implant.

[0030] The biodegradable rib implant features a mechanical support-bone fusion structure within its main body, encased in a thin solid layer to prevent the ingrowth of immature new bone tissue into the surrounding soft tissue during tissue repair. The cross-section of this mechanical support-bone fusion structure is a proportionally scaled rib profile, a variable cross-section, or a circular, elliptical, or I-shaped cross-section. During respiration, the biodegradable rib implant undergoes elastic deformation, allowing the thoracic cavity to expand and contract normally, thus preventing chest tightness, facilitating smooth breathing, and meeting the patient's physiological needs. The cross-sectional area accounts for 30-100% of the implant's main body cross-sectional area, providing the initial strength required to maintain the thoracic structure and for respiratory expansion. Before or during implantation, the main body contains micropores supporting bone tissue growth, with pore sizes ranging from 100 μm to 2 mm.

[0031] like Figure 2As shown, the main cross-section of the biodegradable rib implant includes, but is not limited to, a solid cross-section, an inner solid layer, an outer porous cross-section, an inner porous outer solid cross-section, and a porous-solid-porous cross-section from the inside out.

[0032] The porous structure of the outer layer of the biodegradable rib implant is one or more of the following: through-pore, microrod-based lattice structure, micro-surface-based porous structure, and variable porosity gradient structure, with pore size ranging from 500 μm to 2 mm, for growth infiltration and biological fixation of soft tissue around the rib.

[0033] The biodegradable rib implant described herein can be used independently or in combination with its inner mechanical support-bone fusion structure and outer porous structure. The inner mechanical support-bone fusion structure contacts the bone tissue at the fixed port, and its internal porous structure guides the growth of autologous bone tissue.

[0034] The biodegradable rib implant is fixed using threaded connections, U-shaped clips on both sides of the corresponding defective rib, or sleeve or burr structures. The fixation ports are on both sides of the main body, or auxiliary fixation clamps are designed in the middle of the main body to fix it to the adjacent ribs. One or more of these fixation methods are selected according to the patient's actual situation. The fixation screws or sutures used in the fixation are made of medical biodegradable materials.

[0035] The materials used to prepare the biodegradable rib implants are medical biodegradable polymer materials, biodegradable ceramic materials, or osteoinductive materials, including one or more of polyhydroxyalkanoates (PHA), polycaprolactone (PCL), polyglycolic acid (PGA), polybutylene succinate (PBS) and its copolymers, polyvinyl alcohol (PVA), polylactic acid (PLA) and polylactic acid-glycolic acid copolymer (PLGA), hydroxyapatite (HA), tricalcium phosphate (TCP), calcium sulfate (CaSO3), and calcium carbonate (CaCO3).

[0036] Because biodegradable rib implants are made from biodegradable materials, different structures can be created using materials with different degradation rates. Therefore, biodegradable rib implants can exhibit programmable performance changes after different implantation times; for example... Figure 3 As shown, by embedding a faster-degrading PLGA material into a slower-degrading PCL material, a porous structure can be spontaneously formed as the implantation time increases, effectively providing space for bone tissue growth. Furthermore, by doping the fast-degrading material with osteoinductive materials such as HA, the controlled release of functional materials can be achieved, thereby inducing bone regeneration and fusion. The structural and material combination design and matching of biodegradable sternal and rib implants can enable programmable performance changes as the repair process and stages evolve after implantation, promoting the functional regeneration of autologous tissue.

[0037] The biodegradable rib implant is manufactured using 3D printing technology. By coating or doping the surface with functional materials such as gelatin, collagen, functional materials, and growth factors, the biocompatibility, osteoinductive ability, and osteointegration ability of the implant are improved.

[0038] like Figure 4 As shown, Figure 4 This is a biodegradable rib implant made using 3D printing. The biodegradable rib implant is made of polycaprolactone (PCL), a medical biodegradable polymer material. This material has good ductility, tensile strength, biocompatibility and biodegradability. It can achieve good biofusion with human tissue and is eventually completely replaced and absorbed by the body's own tissue, thus achieving the repair and reconstruction of the ribs.

[0039] The degradation-tissue regeneration-mechanical transformation process of PCL-degradable rib implants in animals, such as... Figure 5 As shown: With prolonged implantation time, autologous fibrous tissue gradually grows and infiltrates into the implant along the porous structure. Six months after implantation, the molecular weight of the PCL implant gradually decreases, while the overall shape of the tissue-implant composite structure shows no significant change (e.g., Figure 6 (As shown in the figure). The above results demonstrate that biodegradable implants can support the growth and infiltration of autologous fibrous connective tissue to form good biofusion, and can achieve the transformation of artificial structures into autologous living tissue while maintaining their shape.

[0040] The biodegradable rib implant has a total length of 30-100mm, with the main body accounting for 20-80% of the total length and the fixing port accounting for 80-20% of the total length.

[0041] The main shape of the biodegradable rib implant is obtained by extracting the patient's medical imaging data, mirroring the contralateral healthy rib, or extracting the feature contour from the normal rib. Its thickness can be adjusted to 100-200% of that of the healthy rib.

Claims

1. A 3D printed degradable costal cartilage implant, characterized in that: The implant includes a main body and a fixed port thereon, wherein the curvature of the main body is consistent with the curvature of the rib defect; the main body has a multi-layer structure, with an inner layer being a mechanical support-bone fusion structure to provide space for maintaining the thoracic structure morphology, initial strength required for respiratory expansion, and new bone tissue growth; the outer layer is a porous structure to facilitate the ingrowth of surrounding soft tissue and subsequent biofusion fixation; the fixed port on the main body is installed and fixed at the corresponding thoracic rib junction; the biodegradable thoracic rib implant is made of materials with different degradation rates to create different structures, with materials with slower degradation rates intercalated into materials with faster degradation rates, and as the implantation time increases, a porous structure is spontaneously formed; by controlling the composition and macro- and micro-structure of the biodegradable material, the function of the biodegradable thoracic rib implant is programmed to achieve dynamic matching and transformation between mechanical stability and tissue regeneration; as the biodegradable thoracic rib implant material degrades, autologous tissue gradually grows, infiltrates, and completely replaces the biodegradable thoracic rib implant; The biodegradable rib implant body's inner mechanical support-bone fusion structure and outer porous structure are used in combination in practical applications. The biodegradable rib implant is fixed by U-shaped clips on both sides of the corresponding defect site, or by a sleeve or burr structure. The fixation ports are on both sides of the main body, or an auxiliary fixation clamp is designed in the middle of the main body to fix it to the adjacent ribs. One or more of these fixation methods are selected according to the patient's actual situation. The biodegradable rib implant has an inner mechanical support-bone fusion structure that is wrapped in a thin solid layer. The cross-section of the mechanical support-bone fusion structure is a proportionally scaled rib cross-section outline that is circular, elliptical, or I-shaped. The cross-sectional area accounts for 30%-100% of the cross-sectional area of ​​the implant body, but not 100%. Before or during implantation, the implant body has micropores that support bone tissue growth, with a pore size of 100μm to 2 mm. The biodegradable rib implants described herein are manufactured using 3D printing technology. By coating or doping the surface with gelatin, collagen, or growth factors, the biocompatibility, osteoinductive ability, and osteointegration ability of the implants are improved. The main shape of the biodegradable rib implant is obtained by extracting the patient's medical imaging data, mirroring the contralateral healthy rib, or extracting the feature contour from the normal rib. Its thickness can be adjusted to 100%-200% of the healthy rib.

2. The 3D printed degradable costal cartilage implant of claim 1, wherein: The porous structure of the outer layer of the biodegradable rib implant body is one or more of the following: through-pores, microrod-based lattice structure, porous structure based on minimal curved surfaces, and gradient structure with variable pore size, with pore size ranging from 500 μm to 2 mm.

3. The 3D printed degradable costal cartilage implant of claim 1, wherein: The materials used to prepare the biodegradable rib implants are medical biodegradable polymer materials, biodegradable ceramic materials, or osteoinductive materials, including one or more of polyhydroxyalkanoates (PHA), polycaprolactone (PCL), polyglycolic acid (PGA), polybutylene succinate (PBS) and its copolymers, polyvinyl alcohol (PVA), polylactic acid (PLA) and polylactic acid-glycolic acid copolymer (PLGA), hydroxyapatite (HA), tricalcium phosphate (TCP), calcium sulfate (CaSO4), and calcium carbonate (CaCO3).

4. The 3D printed degradable costal cartilage implant of claim 1, wherein: The biodegradable rib implant has a total length of 30-100 mm, with the main body accounting for 20%-80% of the total length and the fixed port accounting for 20%-80% of the total length.

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