CN113908344B - Degradable sheathed interface screw assembly and manufacturing process thereof - Google Patents
Degradable sheathed interface screw assembly and manufacturing process thereof Download PDFInfo
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- CN113908344B CN113908344B CN202111160010.8A CN202111160010A CN113908344B CN 113908344 B CN113908344 B CN 113908344B CN 202111160010 A CN202111160010 A CN 202111160010A CN 113908344 B CN113908344 B CN 113908344B
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- A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
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- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
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- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/84—Fasteners therefor or fasteners being internal fixation devices
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
- A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws, setting implements or the like
- A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
- A61B17/84—Fasteners therefor or fasteners being internal fixation devices
- A61B17/86—Pins or screws or threaded wires; nuts therefor
- A61B17/8685—Pins or screws or threaded wires; nuts therefor comprising multiple separate parts
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
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- A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
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- A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
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- A61L31/148—Materials at least partially resorbable by the body
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- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B9/00—Making granules
- B29B9/08—Making granules by agglomerating smaller particles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
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- B29K2071/00—Use of polyethers, e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof, as moulding material
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Abstract
The invention relates to a degradable sheathed interface screw assembly and a manufacturing process thereof. The interface screw and the matched nail sheath raw materials in the manufacturing process are as follows: polylactic acid, hydroxyapatite and beta-tricalcium phosphate. The invention also relates to a specific manufacturing method of the degradable sheathed interface screw assembly, and a screw body of the degradable sheathed interface screw assembly and a matched nail sheath structure thereof. The degradable sheathed interface screw assembly and the manufacturing process thereof solve the problems that the existing titanium alloy interface screw and PEEK interface screw are required to be implanted into a human body for a long time or are required to be taken out by secondary operation to cause product residues or secondary injuries to patients, and the degradable sheathed interface screw assembly can be absorbed by the human body to eliminate the product residues and the secondary injuries, and the secondary operation is not required to be taken out, so that the secondary injuries are avoided; the body and the nail sheath of the interface nail body are designed to form an expansion and compression structure combination, so that the interface nail body has the effects of preventing the screw from breaking and preventing the tendon from being cut in the process of implantation.
Description
Technical Field
The invention relates to the field of medical consumables, in particular to a degradable sheathed interface screw assembly and a manufacturing process thereof.
Background
The interface screw is a medical consumable for treating anterior and posterior cruciate ligament injury and is used for a doctor to reconstruct the cruciate ligament under an arthroscope. Specifically, a doctor weaves autologous tendons of a patient, drills bone tracts for fixing ligaments at the tibia and femur parts of the knee joint respectively, then presses the ligaments on the inner wall of the bone tracts by using interface screws, and finally grows on the bone tracts after the tissue of the human body is repaired, so that the cruciate ligaments of the patient recover functions.
The interface screw applied in China at present mainly takes import, the interface screw which is marketed in China at present also mainly takes titanium alloy materials, and a small amount of PEEK material interface screw begins to appear in China in 2019. Because the titanium alloy interface screw and the PEEK interface screw are implanted into a human body, the titanium alloy interface screw and the PEEK interface screw can stay in the human body for a long time or be taken out by a secondary operation, and the long-time stay and the operation are taken out, the subsequent injury can be brought to a patient. By 2021, 2 months ago, absorbable interface screws were still monopolized by foreign large medical equipment companies, while autonomously produced absorbable interface screws still did not appear in the domestic market.
Disclosure of Invention
The invention aims to solve the technical problems that: the problem that the existing titanium alloy interface screw and PEEK interface screw are required to be implanted into a human body for a long time or are required to be taken out by secondary operation to cause product residues or secondary injuries to patients is solved, and the degradable interface screw assembly with the sheath and the manufacturing process thereof are provided, so that the product residues and the harm can be eliminated, the secondary operation is not required to be taken out, and the secondary injuries are avoided; in addition, through the structural design of the interface nail body, the interface nail body has the effects of preventing the screw from breaking and preventing tendon from being cut in the process of implantation.
The interface screw and the matched nail sheath are manufactured by the following raw materials: polylactic acid, hydroxyapatite and beta-tricalcium phosphate. In the selection of raw materials, the absorbable screw at the interface of the pure polylactic acid is slowly degraded, so that a large amount of lactic acid is generated in middle and late stages, and inflammatory reaction is caused to a patient; polylactic acid/Hydroxyapatite (HA) composite interface screw can effectively solve the problems that degradation is too fast and lactic acid is neutralized due to the existence of alkaline inorganic bone induction materials, but HA is slow in absorption speed and cannot form a pore channel; the problem of polylactic acid/beta-tricalcium phosphate (TCP) composite interface screw is that the absorption rate of TCP is too high, and lactic acid cannot be neutralized in middle and late stages. By combining the reasons, the polylactic acid, the hydroxyapatite and the beta-tricalcium phosphate are mixed and modified, the advantages of the materials are taken, and the beta-tricalcium phosphate generates a pore canal in the early and middle degradation process, so that the dissolution of lactic acid is facilitated, the accumulation of lactic acid is reduced, and the influence of the screw body on the pH value of the whole external environment is reduced.
The raw materials are mixed in parts by weight: 60-80 parts of polylactic acid, 5-30 parts of hydroxyapatite and 5-20 parts of beta-tricalcium phosphate.
Specifically to the type of the main raw material, the polylactic acid is L-polylactic acid.
Specifically to the physical index of the raw materials, the number average molecular weight of the L-polylactic acid is 40-100 ten thousand, the particle size of the hydroxyapatite is 2-50 mu m, and the particle size of the beta-tricalcium phosphate is 60-1000 meshes.
Preferably, the weight portion ratio of the raw materials is as follows: 70 parts of polylactic acid, 20 parts of hydroxyapatite and 10 parts of beta-tricalcium phosphate.
The manufacturing process of the degradable sheathed interface screw assembly specifically comprises the following steps,
s1-mixing: putting millimeter-sized large-particle polylactic acid into a freeze grinder, performing freeze grinding until micron-sized small-particle polylactic acid is ground, and then putting into a vacuum dryer for high-temperature drying; respectively drying the hydroxyapatite and the beta-tricalcium phosphate, and then putting the hydroxyapatite and the beta-tricalcium phosphate into a mechanical stirrer according to the weight part ratio, and stirring until the hydroxyapatite and the beta-tricalcium phosphate are uniformly mixed; putting the dried polylactic acid powder into a mechanical stirrer according to the weight part ratio, and stirring again until the polylactic acid powder is uniformly mixed to obtain mixed raw material powder; after polylactic acid is ground, the particle sizes of the three raw materials tend to be consistent, so that the raw materials are mixed more uniformly, the dispersibility of the composite material is further improved, and the mechanical property of the screw with the cross section of the final product is finally improved;
s2-pressing: putting the mixed raw material powder obtained by mixing in the step S1 into a tablet press, and pressing the mixed raw material powder into composite particles; the pressing process does not heat the raw materials, so that the molecular weight of the raw materials is not reduced in the processing process;
s3-precision injection molding: and (3) putting the composite particles obtained by pressing in the step (S2) into a miniature screw type precise injection molding machine, heating the composite particles, pressurizing and injecting the composite particles into a mold, and respectively preparing the interface screw and the nail sheath after pressure maintaining and demolding. Specifically, an electric heating system of the micro screw type precise injection molding machine is started, the temperature is set between 180 and 260 ℃, and after the actual temperature and the set temperature of the micro screw type precise injection molding machine are consistent, materials are injected into a mold adopting a separated heating mode through the pressure of 200 to 300bar.
Specifically to the process conditions, the freezing temperature of the freeze grinding in the step S1 is-196+/-10 ℃ liquid nitrogen, the cooling time is 5-100 min, the grinding time is 10-120 min, and the vacuum drying temperature is 40-80 ℃ and the drying time is 0.5-8 h. The storage tank is arranged in the storage tank; and step S3, setting the heating temperature of the precise injection molding machine to be 180-260 ℃ and the pressurizing pressure to be 200-300 bar.
The degradable sheathed interface screw assembly comprises a screw body and a cutting-resistant ligament nail sheath screwed with the screw body, wherein a fracture-resistant structure is arranged inside the screw body, and the fracture-resistant structure is a core rod filling type driving structure arranged at the central axis of the screw body.
Specifically, the core rod filling type driving structure comprises a polygonal through groove arranged in the center of the screw body and a polygonal screwdriver penetrating through the polygonal through groove, and the polygonal screwdriver is tightly assembled with the polygonal through groove. In the core rod filling type driving structure, a high-strength core rod which penetrates through the whole interface screw and is completely matched is matched, so that the rotating force is uniformly dispersed to the whole screw, and the screw is prevented from being twisted and broken.
Specifically, the outer wall of the screw body is provided with external threads with smooth threads, and the inner wall of the anti-cutting ligament nail sheath is provided with thread grooves matched with the external threads; an expansion head is arranged at the upper part of the anti-cutting ligament nail sheath, and an anti-drop thread which is subjected to smooth treatment is formed on the outer wall of the expansion head; the edge of the lower end of the anti-cutting ligament nail sheath is provided with an arc smooth transition part. Punching holes on bones of a patient in the operation process of a doctor, taking autologous tendons of the patient to penetrate into bone tracts, reserving a part at the tail part, and combining the tendons with the bone tracts; the tendon reserved at the tail part is separated at the bone meatus, the ligament is extruded on the inner wall of the bone meatus by taking the anti-cutting ligament nail sheath in the deformation space, and then the screw body is screwed into the anti-cutting ligament nail sheath, and the expansion head is used for expanding the piece, so that the tendon is attached to the bone meatus. The edge of the front end of the nail sheath is provided with the arc smooth transition part, in the process of implanting the interface screw assembly, the screw body threads do not contact with tendons to generate friction, the upper part of the anti-cutting ligament nail sheath is propped open and then the tendons are tightly pressed by the similar expansion bolts in the screwing process, and the tendon cutting is effectively avoided.
The degradable sheathed interface screw assembly and the manufacturing process thereof solve the problems that the existing titanium alloy interface screw and PEEK interface screw are required to be implanted into a human body for a long time or are required to be taken out by secondary operation to cause product residues or secondary injuries to patients, can be absorbed by the human body, eliminate the product residue harm, do not need to be taken out by secondary operation, and avoid secondary injuries; in addition, the body and the nail sheath of the interface nail body are designed to form an expansion and compression structure combination, so that the screw has the effects of preventing the screw from breaking and preventing the tendon from being cut in the process of implantation.
Drawings
The invention is further described with reference to the drawings in which:
FIG. 1 is a schematic view of an exploded construction of the present degradable sheathed interface screw assembly;
FIG. 2 is a schematic top plan view of the present degradable sheathed interface screw assembly;
FIG. 3 is a scanning electron microscope image of the present degradable sheathed interface screw assembly;
FIG. 4 is a graph of in vitro degradation pH change for the present degradable sheathed interface screw assembly.
In the figure:
1-a screw body; 11-external threads;
2-cutting-preventing ligament nailing sheath; 21-expansion head, 22-anti-drop screw thread and 23-arc smooth transition part; 3-a fracture preventing structure; 31-polygonal through groove, 32-polygonal screwdriver.
Detailed Description
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the description of the present invention, it should be understood that the terms "left", "right", "front", "rear", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.
The technical solution of the present invention will be further described with reference to the following specific examples, but the scope of the present invention is not limited to the following examples and embodiments. As shown in figures 1 to 4 of the drawings,
example 1: taking 60 parts of levorotatory polylactic acid, 30 parts of hydroxyapatite and 10 parts of beta-tricalcium phosphate, putting millimeter-sized large-particle polylactic acid into a freezing grinder, carrying out freezing grinding until micron-sized small-particle polylactic acid is ground, wherein the freezing temperature is liquid nitrogen at minus 196+/-10 ℃, the cooling time is 5-100 min, the grinding time is 10-120 min, then putting into a vacuum dryer, carrying out high-temperature drying, and the vacuum drying temperature is 40-80 ℃ and the drying time is 0.5-8 h; respectively drying the hydroxyapatite and the beta-tricalcium phosphate, and then putting the hydroxyapatite and the beta-tricalcium phosphate into a mechanical stirrer according to the weight part ratio, and stirring until the hydroxyapatite and the beta-tricalcium phosphate are uniformly mixed; and (3) putting the dried polylactic acid powder into a mechanical stirrer according to the weight part ratio, and stirring again until the polylactic acid powder is uniformly mixed to obtain mixed raw material powder. And (3) putting the mixed raw material powder obtained by mixing into a tablet press, and pressing the mixed raw material powder into composite particles. And (3) putting the pressed composite particles into a micro screw type precise injection molding machine, heating the composite particles, pressurizing and injecting the composite particles into a mold, and maintaining pressure and demolding to obtain the interface screw and the sheath. Specifically, an electric heating system of the micro screw type precise injection molding machine is started, the temperature is set between 180 and 260 ℃, and after the actual temperature and the set temperature of the micro screw type precise injection molding machine are consistent, materials are injected into a mold adopting a separated heating mode through the pressure of 200 to 300bar.
Example 2: taking 65 parts of L-polylactic acid, 30 parts of hydroxyapatite and 5 parts of beta-tricalcium phosphate, putting millimeter-sized large-particle polylactic acid into a freeze grinder, carrying out freeze grinding until micron-sized small-particle polylactic acid is ground, wherein the freezing temperature is liquid nitrogen at minus 196+/-10 ℃, the cooling time is 5-100 min, the grinding time is 10-120 min, then putting into a vacuum dryer, carrying out high-temperature drying, and the vacuum drying temperature is 40-80 ℃ and the drying time is 0.5-8 h; respectively drying the hydroxyapatite and the beta-tricalcium phosphate, and then putting the hydroxyapatite and the beta-tricalcium phosphate into a mechanical stirrer according to the weight part ratio, and stirring until the hydroxyapatite and the beta-tricalcium phosphate are uniformly mixed; and (3) putting the dried polylactic acid powder into a mechanical stirrer according to the weight part ratio, and stirring again until the polylactic acid powder is uniformly mixed to obtain mixed raw material powder. And (3) putting the mixed raw material powder obtained by mixing into a tablet press, and pressing the mixed raw material powder into composite particles. And (3) putting the pressed composite particles into a micro screw type precise injection molding machine, heating the composite particles, pressurizing and injecting the composite particles into a mold, and maintaining pressure and demolding to obtain the interface screw and the sheath. Specifically, an electric heating system of the micro screw type precise injection molding machine is started, the temperature is set between 180 and 260 ℃, and after the actual temperature and the set temperature of the micro screw type precise injection molding machine are consistent, materials are injected into a mold adopting a separated heating mode through the pressure of 200 to 300bar.
Example 3: taking 70 parts of L-polylactic acid, 25 parts of hydroxyapatite and 5 parts of beta-tricalcium phosphate, putting millimeter-sized large-particle polylactic acid into a freeze grinder, carrying out freeze grinding until micron-sized small-particle polylactic acid is ground, wherein the freezing temperature is liquid nitrogen at minus 196+/-10 ℃, the cooling time is 5-100 min, the grinding time is 10-120 min, and then putting into a vacuum dryer for high-temperature drying, and the vacuum drying temperature is 40-80 ℃ and the drying time is 0.5-8 h; respectively drying the hydroxyapatite and the beta-tricalcium phosphate, and then putting the hydroxyapatite and the beta-tricalcium phosphate into a mechanical stirrer according to the weight part ratio, and stirring until the hydroxyapatite and the beta-tricalcium phosphate are uniformly mixed; and (3) putting the dried polylactic acid powder into a mechanical stirrer according to the weight part ratio, and stirring again until the polylactic acid powder is uniformly mixed to obtain mixed raw material powder. And (3) putting the mixed raw material powder obtained by mixing into a tablet press, and pressing the mixed raw material powder into composite particles. And (3) putting the pressed composite particles into a micro screw type precise injection molding machine, heating the composite particles, pressurizing and injecting the composite particles into a mold, and maintaining pressure and demolding to obtain the interface screw and the sheath. Specifically, an electric heating system of the micro screw type precise injection molding machine is started, the temperature is set between 180 and 260 ℃, and after the actual temperature and the set temperature of the micro screw type precise injection molding machine are consistent, materials are injected into a mold adopting a separated heating mode through the pressure of 200 to 300bar.
Example 4: taking 80 parts of L-polylactic acid, 15 parts of hydroxyapatite and 5 parts of beta-tricalcium phosphate, putting millimeter-sized large-particle polylactic acid into a freeze grinder, carrying out freeze grinding until micron-sized small-particle polylactic acid is ground, wherein the freezing temperature is liquid nitrogen at minus 196+/-10 ℃, the cooling time is 5-100 min, the grinding time is 10-120 min, and then putting into a vacuum dryer for high-temperature drying, and the vacuum drying temperature is 40-80 ℃ and the drying time is 0.5-8 h; respectively drying the hydroxyapatite and the beta-tricalcium phosphate, and then putting the hydroxyapatite and the beta-tricalcium phosphate into a mechanical stirrer according to the weight part ratio, and stirring until the hydroxyapatite and the beta-tricalcium phosphate are uniformly mixed; and (3) putting the dried polylactic acid powder into a mechanical stirrer according to the weight part ratio, and stirring again until the polylactic acid powder is uniformly mixed to obtain mixed raw material powder. And (3) putting the mixed raw material powder obtained by mixing into a tablet press, and pressing the mixed raw material powder into composite particles. And (3) putting the pressed composite particles into a micro screw type precise injection molding machine, heating the composite particles, pressurizing and injecting the composite particles into a mold, and maintaining pressure and demolding to obtain the interface screw and the sheath. Specifically, an electric heating system of the micro screw type precise injection molding machine is started, the temperature is set between 180 and 260 ℃, and after the actual temperature and the set temperature of the micro screw type precise injection molding machine are consistent, materials are injected into a mold adopting a separated heating mode through the pressure of 200 to 300bar.
Embodiment 1: the degradable sheathed interface screw assembly comprises a screw body 1 and a cutting-resistant ligament nail sheath 2 screwed with the screw body 1, wherein an anti-fracture structure 3 is arranged inside the screw body 1, and the anti-fracture structure 3 is a core rod filling type driving structure arranged at the central axis of the screw body 1. The core rod filling type driving structure comprises a polygonal through groove 31 formed in the center of the screw body 1 and a polygonal screwdriver 32 penetrating the polygonal through groove 31, wherein the polygonal screwdriver 32 is tightly assembled with the polygonal through groove 31. In the core rod filling type driving structure, a high-strength core rod which penetrates through the whole interface screw and is completely matched is matched, so that the rotating force is uniformly dispersed to the whole screw, and the screw is prevented from being twisted and broken. The outer wall of the screw body 1 is provided with external threads 11 with smooth threads, and the inner wall of the anti-cutting ligament nail sheath 2 is provided with thread grooves matched with the external threads 11; the upper part of the anti-cutting ligament nail sheath 2 is provided with an expansion head 21, and the outer wall of the expansion head 21 is provided with a smooth anti-drop thread 22; the edge of the lower end of the anti-cutting ligament nail sheath 2 is provided with an arc smooth transition part 23. Punching holes on bones of a patient in the operation process of a doctor, taking autologous tendons of the patient to penetrate into bone tracts, reserving a part at the tail part, and combining the tendons with the bone tracts; the tendon reserved at the tail part is separated at the bone meatus, the ligament is extruded on the inner wall of the bone meatus by taking the anti-cutting ligament nail sheath in the deformation space, and then the screw body is screwed into the anti-cutting ligament nail sheath, and the expansion head is used for expanding the piece, so that the tendon is attached to the bone meatus. The edge of the front end of the nail sheath is provided with the arc smooth transition part, in the process of implanting the interface screw assembly, the screw body threads do not contact with tendons to generate friction, the upper part of the anti-cutting ligament nail sheath is propped open and then the tendons are tightly pressed by the similar expansion bolts in the screwing process, and the tendon cutting is effectively avoided.
Performance test:
the interfacial screw assemblies from examples 1 to 4, equipped with a screwdriver, were tested for pullout resistance, torque, molecular weight, and the results are given in the following table,
| examples | Anti-pull-out force N of phi 6.0mm screw assembly | Molecular weight | Phi 6.0mm screw assembly torque N/m |
| Example 1 | 840±30 | 22000±5000 | 1.3±0.1 |
| Example 2 | 836±30 | 22000±5000 | 1.3±0.1 |
| Example 3 | 823±30 | 22000±5000 | 1.3±0.1 |
| Example 4 | 783±30 | 22000±5000 | 1.3±0.1 |
In the table above, the N-screw assembly resists pullout force; n/m torque.
Conclusion: the test results show that the mechanical properties and molecular weight of the interface screw assembly obtained by the process are greatly increased compared with those of the existing medical screw products.
The degradable sheathed interface screw assembly and the manufacturing process thereof solve the problems that the existing titanium alloy interface screw and PEEK interface screw are required to be implanted into a human body for a long time or are required to be taken out by secondary operation to cause product residues or secondary injuries to patients, and the degradable sheathed interface screw assembly can be absorbed by the human body to eliminate the product residues and the secondary injuries, and the secondary operation is not required to be taken out, so that the secondary injuries are avoided; in addition, the body and the nail sheath of the interface nail body are designed to form an expansion and compression structure combination, so that the screw has the effects of preventing the screw from breaking and preventing the tendon from being cut in the process of implantation.
The foregoing description illustrates the major features, principles, and advantages of the invention. It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments or examples, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing implementations or examples should be regarded as illustrative rather than limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.
Claims (5)
1. A manufacturing method of a degradable sheathed interface screw assembly is characterized in that: the interface screw and the matched nail sheath are manufactured by processing the following raw materials: polylactic acid, hydroxyapatite, beta-tricalcium phosphate; the manufacturing method comprises the following steps,
s1-mixing: putting millimeter-sized large-particle polylactic acid into a freeze grinder, performing freeze grinding until micron-sized small-particle polylactic acid is ground, and then putting into a vacuum dryer for high-temperature drying; respectively drying the hydroxyapatite and the beta-tricalcium phosphate, and then putting the hydroxyapatite and the beta-tricalcium phosphate into a mechanical stirrer for stirring until the hydroxyapatite and the beta-tricalcium phosphate are uniformly mixed; putting the dried polylactic acid powder into a mechanical stirrer, and stirring again until the polylactic acid powder is uniformly mixed to obtain mixed raw material powder;
s2-pressing: putting the mixed raw material powder obtained by mixing in the step S1 into a tablet press, and pressing the mixed raw material powder into composite particles;
s3-injection molding: putting the composite particles obtained by pressing in the step S2 into a miniature screw type precise injection molding machine, heating the composite particles, pressurizing and injecting the composite particles into a mold, and respectively preparing the interface screw and the sheath after pressure maintaining and demolding;
the degradable sheathed interface screw assembly comprises a screw body (1) and a cutting-resistant ligament nail sheath (2) which is screwed with the screw body (1), wherein an anti-fracture structure (3) is arranged inside the screw body (1), and the anti-fracture structure (3) is a core rod filling type driving structure arranged at the central axis of the screw body (1); the core rod filling type driving structure comprises a polygonal through groove (31) arranged in the center of the screw body (1) and a polygonal screwdriver (32) penetrating into the polygonal through groove (31), wherein the polygonal screwdriver (32) is tightly assembled with the polygonal through groove (31); an external thread (11) with smooth threads is arranged on the outer wall of the screw body (1), and a thread groove matched with the external thread (11) is arranged on the inner wall of the anti-cutting ligament nail sheath (2); an expansion head (21) is arranged at the upper part of the anti-cutting ligament nail sheath (2), and an anti-drop thread (22) which is smoothly treated is formed on the outer wall of the expansion head (21); the edge of the lower end of the anti-cutting ligament nail sheath (2) is provided with an arc smooth transition part (23).
2. The method of manufacturing a degradable sheathed interface screw assembly of claim 1, wherein: the weight part ratio range of the raw materials is as follows: 60-80 parts of polylactic acid, 15-30 parts of hydroxyapatite and 5-20 parts of beta-tricalcium phosphate.
3. The method of manufacturing a degradable sheathed interface screw assembly of claim 2, wherein: the polylactic acid is L-polylactic acid.
4. A method of manufacturing a degradable sheathed interface screw assembly according to claim 3, characterized by: the number average molecular weight of the L-polylactic acid is 40-100 ten thousand, the particle size of the hydroxyapatite is 2-50 mu m, and the particle size of the beta-tricalcium phosphate is 60-1000 meshes.
5. The method of manufacturing a degradable sheathed interface screw assembly of claim 4, wherein: the weight portion ratio of the raw materials is as follows: 70 parts of polylactic acid, 20 parts of hydroxyapatite and 10 parts of beta-tricalcium phosphate.
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| CN209347110U (en) * | 2018-11-29 | 2019-09-06 | 北京天星博迈迪医疗器械有限公司 | Follow closely fixed system in a kind of band sheath interface |
| CN111359025B (en) * | 2020-04-15 | 2022-03-15 | 花沐医疗科技(上海)有限公司 | Orderly-absorbed composite absorbable interface screw system with sheath and preparation method thereof |
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