A method of making and using a bone fracture internal fixation bone pin system

Abstract

The application belongs to the technical field of medical devices, and particularly relates to a manufacturing and using method of a fracture internal fixation bone nail system; the second nail cap and the first nail cap are bonded together in a local dissolving or local melting mode, the bonding part comprises the whole upper plane and the side surface of the first top cap, the stress area is larger during use, the effect of holding the bone nail is better, the nail cap is thinner, and the nail cap is more suitable for clinical use.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to the manufacturing and use of an internal fixation bone screw system for fractures. Background Technology

[0002] In fracture surgery, absorbable bone screws can be used for treatment. These screws degrade within the body and are absorbed as the fracture heals, eliminating the need for a second surgery and making them popular with both doctors and patients. However, plastic absorbable bone screws are less strong than metal screws, and their heads are not suitable for internal drive connection structures. Internal drive connection structures, such as hexagonal, slotted, or Phillips head screws, are prone to damage to the screw head and render it unusable if resistance is encountered during screw insertion.

[0003] Currently, a major solution is to use a metal nail head, with one end connected to the drive connector and the other end gripping the nail body through several clamping claws with interference fit. This method only involves a few claws bearing force, resulting in a small force-bearing area and poor clamping effect on bone nails.

[0004] For bone screws made of absorbable materials to form a good connection with the drive connection tool, a larger screw head volume and a larger drive contact area are required; however, a large screw head is prone to protruding from the bone surface, causing irritation to the body.

[0005] Therefore, how to manufacture fracture internal fixation nails with larger nail heads and larger driving contact areas is an urgent problem to be solved in this field. Summary of the Invention

[0006] To overcome the above problems, the present invention provides a method for manufacturing and using an internal fixation bone screw system for fractures. The second screw cap and the first screw cap are bonded together by local dissolution or local melting. The bonded part includes the entire upper surface and side of the first screw cap, resulting in a larger force-bearing area, better retention of the bone screw, and a thinner screw cap, making it more suitable for clinical use.

[0007] A method of using an internal fixation bone screw system for fractures, wherein the internal fixation bone screw system includes a bone screw 1 and a second screw cap 2, the bone screw 1 includes a screw body 12 and a first screw cap 11, wherein the first screw cap 11 is disposed on the top of the screw body 12, the second screw cap 2 has a driving end 21 at the top and an adhesive end 22 at the bottom, the adhesive end 22 being fixed to the top of the first screw cap 11; the method of use includes:

[0008] Step 1: Clamp the driving end 21 at the top of the second nail cap 2 and insert the bone nail 1 into the required position in the body;

[0009] Step two, the bone nail 1 and the second nail head 2 are separated by applying opposing forces between the first nail head 11 and the second nail head 2.

[0010] The opposite force is applied by shaking outward, leftward, rightward, upward, and downward to break the connection between the bone nail 1 and the second nail cap 2, and then pulling out the second nail cap 2.

[0011] The application of the opposite force is as follows: an ejection hole 24 is provided inside the second nail head 2, which is achieved by using a driving tool. The driving tool extends an ejection rod through the ejection hole 24 of the second nail head 2 and presses it on the first nail head 11 of the bone nail 1. Then it holds the second nail head 2 and pulls it outward until the bone nail 1 and the second nail head 2 are separated.

[0012] A method for fabricating an internal fixation screw system for fractures includes the following three methods:

[0013] The internal fixation bone screw system for fractures includes a bone screw 1 and a second screw cap 2. The bone screw 1 includes a screw body 12 and a first screw cap 11, wherein the first screw cap 11 is disposed on the top of the screw body 12, and the second screw cap 2 has a driving end 21 at the top and an adhesive end 22 at the bottom. The manufacturing method includes fixing the adhesive end 22 to the top of the first screw cap 11 by adhesive bonding.

[0014] A method for manufacturing an internal fixation screw system for fractures includes heating the top of a first screw cap 11 and the bottom of the adhesive end 22 of a second screw cap 2, or simultaneously heating the top of the first screw cap 11 and the bottom of the adhesive end 22 of the second screw cap 2, so that the top of the first screw cap 11 and the bottom of the adhesive end 22 of the second screw cap 2 melt, or the top of the first screw cap 11 and the bottom of the adhesive end 22 of the second screw cap 2 melt simultaneously; then pressing the bottom of the adhesive end 22 of the second screw cap 2 onto the top of the first screw cap 11, so that the first screw cap 11 is bonded to the adhesive end 22 of the second screw cap 2; cooling and curing to achieve stable bonding of the screw 1 and the second screw cap 2.

[0015] Apply a plastic solution to the top of the first nail head 11, then press the first nail head 11 with the plastic solution onto the bottom of the adhesive end 22 of the second nail head 2. After the solvent in the plastic solution evaporates, the bone nail 1 and the second nail head 2 are bonded together.

[0016] The plastic solution is in which plastic is dissolved as a solute in a benign solvent.

[0017] The top of the first nail head 11 is partially dissolved by a plastic solvent, forming a plastic solution on the top of the first nail head 11. The plastic solution formed on the top of the first nail head 11 is then used as an adhesive to press the adhesive end 22 at the bottom of the second nail head 2 onto the top of the first nail head 11. After the solvent in the plastic solution formed on the top of the first nail head 11 evaporates, the bone nail 1 and the second nail head 2 are bonded together.

[0018] The bone nail 1 is made of plastic, or a composite of metal, metal oxide, and inorganic salt in plastic material, wherein the mass percentage of plastic material is 10.0% to 99.9%.

[0019] The metals are stainless steel, titanium alloy, iron, tantalum, and magnesium-aluminum alloy; the metal oxides are iron carbide and iron nitride; the inorganic salts are hydroxyapatite and tricalcium phosphate; and the plastic material is absorbable or non-absorbable.

[0020] The beneficial effects of this invention are:

[0021] This invention relates to a method for manufacturing a bone screw with a double-head structure. The second head and the first head are bonded together by partial dissolution or partial melting, thereby creating a bone screw with a second head. This results in a larger head volume and a larger driving contact area, which is convenient for clamping and allows the first head to be thinner, smaller in size, and better fits the bone surface. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of the functional component of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of another embodiment of the active component of the present invention.

[0025] Wherein: 1-bone screw; 2-second screw cap; 11-first screw cap; 12-screw body; 13-bone screw hole; 21-driving end; 22-adhesive end; 23-claw; 24-ejection hole. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0027] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0029] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0030] Example 1

[0031] A method of using an internal fixation bone screw system for fractures, wherein the internal fixation bone screw system includes a bone screw 1 and a second screw cap 2, the bone screw 1 includes a screw body 12 and a first screw cap 11, wherein the first screw cap 11 is disposed on the top of the screw body 12, the second screw cap 2 has a driving end 21 at the top and an adhesive end 22 at the bottom, the adhesive end 22 being fixed to the top of the first screw cap 11; the method of use includes:

[0032] Step 1: Clamp the driving end 21 at the top of the second nail cap 2 and insert the bone nail 1 into the required position in the body;

[0033] Step two, the bone nail 1 and the second nail head 2 are separated by applying opposing forces between the first nail head 11 and the second nail head 2.

[0034] The opposite force is applied by shaking outward, leftward, rightward, upward, and downward to break the connection between the bone nail 1 and the second nail cap 2, and then pulling out the second nail cap 2.

[0035] The application of the opposite force is achieved by setting an ejection hole 24 inside the second nail head 2 and using a driving tool. The driving tool extends an ejection rod through the ejection hole 24 of the second nail head 2 and presses it on the first nail head 11 of the bone nail 1. Then it holds the second nail head 2 and pulls it outward until the bone nail 1 and the second nail head 2 are separated.

[0036] A method for fabricating an internal fixation screw system for fractures includes the following three methods:

[0037] The internal fixation bone screw system for fractures includes a bone screw 1 and a second screw cap 2. The bone screw 1 includes a screw body 12 and a first screw cap 11, wherein the first screw cap 11 is disposed on the top of the screw body 12, and the second screw cap 2 has a driving end 21 at the top and an adhesive end 22 at the bottom. The manufacturing method includes fixing the adhesive end 22 to the top of the first screw cap 11 by adhesive bonding.

[0038] A method for manufacturing an internal fixation screw system for fractures includes heating the top of a first screw cap 11 and the bottom of the adhesive end 22 of a second screw cap 2, or simultaneously heating the top of the first screw cap 11 and the bottom of the adhesive end 22 of the second screw cap 2, so that the top of the first screw cap 11 and the bottom of the adhesive end 22 of the second screw cap 2 melt, or the top of the first screw cap 11 and the bottom of the adhesive end 22 of the second screw cap 2 melt simultaneously; then pressing the bottom of the adhesive end 22 of the second screw cap 2 onto the top of the first screw cap 11, so that the first screw cap 11 is bonded to the adhesive end 22 of the second screw cap 2; cooling and curing to achieve stable bonding of the screw 1 and the second screw cap 2.

[0039] Apply a plastic solution to the top of the first nail head 11, then press the first nail head 11 with the plastic solution onto the bottom of the adhesive end 22 of the second nail head 2. After the solvent in the plastic solution evaporates, the bone nail 1 and the second nail head 2 are bonded together.

[0040] The plastic solution is in which plastic is dissolved as a solute in a benign solvent.

[0041] The top of the first nail head 11 is partially dissolved by a plastic solvent, forming a plastic solution on the top of the first nail head 11. The plastic solution formed on the top of the first nail head 11 is then used as an adhesive to press the adhesive end 22 at the bottom of the second nail head 2 onto the top of the first nail head 11. After the solvent in the plastic solution formed on the top of the first nail head 11 evaporates, the bone nail 1 and the second nail head 2 are bonded together.

[0042] The bone nail 1 is made of plastic, or a composite of metal, metal oxide, and inorganic salt in plastic material, wherein the mass percentage of plastic material is 10.0% to 99.9%.

[0043] The metals are stainless steel, titanium alloy, iron, tantalum, and magnesium-aluminum alloy; the metal oxides are iron carbide and iron nitride; the inorganic salts are hydroxyapatite and tricalcium phosphate; and the plastic material is absorbable or non-absorbable.

[0044] The method described above utilizes an internal fixation system for fractures, comprising a bone screw 1 and a second screw cap 2. One end of the bone screw 1 is the screw body 12, and the other end is the first screw cap 11. One end of the second screw cap 2 is a driving end 21, and the other end is an adhesive end 22. The adhesive end 22 of the second screw cap 2 and the first screw cap 11 of the bone screw 1 are bonded together to form a fixation system. By twisting the driving end 21 of the second screw cap 2 with a tool, the bone screw 1 is rotated, thereby achieving implantation of the bone screw 1. After implantation, the second screw cap 2 can be separated from the first screw cap 11 of the bone screw 1 using a certain method.

[0045] The first nail head 11 and the second nail head 2 of the bone nail 1 are bonded together. To make the bonding stronger, the surface of the bonding surface 22 of the second nail head 2 should be rough or have a special texture that is conducive to bonding.

[0046] The first nail head 11 and the second nail head 2 of the bone nail 1 are bonded together. To make the bonding stronger, the bonding surface 22 of the second nail head 2 can have claws 23. The claws 23 penetrate into the first nail head 11 to achieve higher bonding strength and torsional strength.

[0047] The number of claws 23 is not less than 2. The claws 23 may extend into the first nail head 11 along the edge of the first nail head 11 or may not extend into the first nail head 11 along the edge of the first nail head 11.

[0048] The bone nail 1 is made of plastic, which may contain composites of metals, metal oxides, and inorganic salts, with the plastic material comprising 10.0% to 99.9%. Examples of metals include stainless steel, titanium alloys, iron, tantalum, and magnesium-aluminum alloys; examples of metal oxides include iron carbide and iron nitride; and examples of inorganic salts include hydroxyapatite and tricalcium phosphate. The plastic material can be absorbable or non-absorbable.

[0049] The bone screw 1 can be solid or hollow. A solid bone screw 1 means that the bone screw 1 has no holes, while a hollow bone screw 1 generally means that the bone screw 1 has axial bone screw holes 13.

[0050] After the bone screw 1 is implanted, it can be separated from the second screw cap 2 in a certain way. Opposite forces can be applied between the first screw cap 11 and the second screw cap 2 to tear them apart. Applying opposite forces can be, for example, by directly shaking outwards, left and right, up and down to pry open the connection between the bone screw 1 and the second screw cap 2, and then pulling out the second screw cap 2. Alternatively, the tool can have a device that extends an ejector rod through the ejector hole 24 of the second screw cap 2, presses against the first screw cap 11 of the bone screw 1, holds the second screw cap 2, and pulls it outwards until the bone screw 1 and the second screw cap 2 are separated.

[0051] The diameter of the nail body 12 of the bone nail 1 is 1-15mm, and the length is 5-150mm.

[0052] Example 2

[0053] A profile made of 100% L-polylactic acid is machined into a bone nail 1 with a diameter of 3.5 mm. The first nail head 11 is hemispherical. The driving end 21 of the second nail head 2 has a cross groove, and the bonding end 33 has knurling with a depth of 0.1 mm. The second nail head 3 has no center hole.

[0054] Sample 1 is obtained by heating the second nail cap 3 to 230 degrees Celsius and then pressing the second nail cap 3 and the bone nail 1 together until they cool.

[0055] The first nail head 11 of the bone screw 1 is electrically heated until the surface turns red and softens. Then the second nail head 2 and the first nail head 11 of the bone screw 1 are pressed together until cooled to obtain sample 2.

[0056] Example 3

[0057] A profile is formed from a composite material of 90% L-polylactic acid and 10% hydroxyapatite, and machined into a bone nail 1 with a diameter of 4.5 mm. The first nail head 11 is hemispherical and has a groove that mates with the claws 23 of the adhesive end 22. The driving end 21 of the second nail head 2 has an internal hexagonal groove, and the adhesive end 22 has claws 23 with a height of 0.5 mm. The second nail head 2 has a central hole.

[0058] Select a heated and melted L-type polylactic acid (PLA) molten adhesive. Dip the first cap 11 of the bone screw 1 into the molten PLA, and quickly press the adhesive end 22 of the second cap 2 onto the first cap 11 of the bone screw 1 (with the claws 23 aligning with the grooves). Continue until cooling to obtain sample 3. The second cap 2 has two claws 23, which are symmetrically arranged on the second cap 2, not on the outer edge of the second cap 2.

[0059] Example 4

[0060] A profile is formed from a composite material of 90% L-polylactic acid and 10% hydroxyapatite, and machined into a bone nail 1 with a diameter of 4.5 mm. The first nail head 11 is hemispherical and has a groove that mates with the claws 23 of the adhesive end 22. The driving end 21 of the second nail head 2 has an internal hexagonal groove, and the adhesive end 22 has claws 23 with a height of 0.5 mm. The second nail head 2 has a central hole.

[0061] Using a chloroform solution of 20% L-polylactic acid and 2% hydroxyapatite as an adhesive, the adhesive end 22 of the second nail cap 2 and the first nail cap 11 of the bone nail 1 were pressed together. After the solvent chloroform completely evaporated, sample 4 was obtained. The second nail cap 2 has four claws 23, which are evenly arranged on the outer edge of the second nail cap 2.

[0062] Alternatively, the first nail head 11 of the bone screw 1 can be immersed in chloroform solvent until the surface of the first nail head 11 melts. Then, the second nail head 2 and the bone screw 1 are pressed together. After the chloroform solvent has completely evaporated, sample 5 is obtained. The second nail head 2 has three claws 23, which are evenly arranged on the outer edge of the second nail head 2.

[0063] Example 5

[0064] A profile is formed from polylactic acid (PLA) containing 6% dextrorotatory and 94% levorotatory components. This profile is then machined into a bone screw 1 with a diameter of 4.0 mm. The first screw head 11 is conical with threads on the conical surface for locking with the bone plate. The first screw head 11 does not have a groove for engaging with the claws 23 of the bonding end 22. The second screw head 2 has a drive end 21 with an internal hexagonal groove, and a 0.6 mm high claw 23 on the bonding end 22. The second screw head 2 also has a central hole.

[0065] The bone screw 1 is fixed by the conical surface of the first nail head 11, and the adhesive end 22 of the second nail head 2 is welded to the first nail head 11 of the bone screw 1 by ultrasonic waves to obtain sample 6. The second nail head 2 has four claws 23, which are evenly arranged on the second nail head 2 and not on the outer edge of the second nail head 2.

[0066] Example 6

[0067] The sample 7 is produced by injection molding, with the second nail cap 2 as an insert placed in the mold. The material is a 10% glycolide polymer, which is heated and melted before being injected into the mold. The second nail cap 2 has four claws 23, which are symmetrically arranged on the second nail cap 2.

[0068] test

[0069] Using a tensile testing machine, the maximum tensile force between bone screw 1 and the second screw cap 2 was tested, and the data in the table below were obtained.

[0070] Sample Name Average maximum tensile force (N) Remark Sample 1 29 The nail head is intact and undamaged. Sample 2 33 The nail head is intact and undamaged. Sample 3 36 The nail head is intact and undamaged. Sample 4 40 The nail head is intact and undamaged. Sample 5 35 The nail head is intact and undamaged. Sample 6 50 The nail head is intact and undamaged. Sample 7 44 The nail head is intact and undamaged.

[0071] Based on the experimental data, the maximum tensile force between the bone screw 1 and the second screw cap 2 in all samples was 29 to 50 N. After the bone screw 1 was implanted, the second screw cap 2 was pulled directly to separate the two, and the first screw cap 1 remained intact. The first screw cap 11 was not damaged due to excessive adhesive force, which proves that the adhesive method is feasible.

[0072] Of course, using a driving tool to apply an opposing force between the second nail cap 2 and the bone screw 1 would make it easier for doctors to use.

[0073] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the scope of protection of the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, any person skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention within the scope of the technology disclosed in the present invention. These simple modifications are all within the scope of protection of the present invention.

[0074] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0075] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for manufacturing an internal fixation screw system for fractures, characterized in that, The internal fixation bone screw system for fractures includes a bone screw (1) and a second screw cap (2). The bone screw (1) includes a screw body (12) and a first screw cap (11). The first screw cap (11) is located on the top of the screw body (12). The top of the second screw cap (2) is a driving end (21), and the bottom is an adhesive end (22). The manufacturing method includes fixing the adhesive end (22) to the top of the first screw cap (11) by adhesive bonding. The internal fixation screw system for fractures also includes a driving tool, which includes an ejector rod. The screw (1) and the second screw cap (2) are separated by applying opposite forces between the first screw cap (11) and the second screw cap (2). The opposite forces are applied as follows: an ejector hole (24) is provided inside the second screw cap (2). The driving tool extends the ejector rod through the ejector hole (24) of the second screw cap (2) and presses it on the first screw cap (11) of the screw (1). Then, it holds the second screw cap (2) and pulls it outward until the screw (1) and the second screw cap (2) are separated. The adhesive end (22) of the second nail head (2) is provided with claws (23), which penetrate into the first nail head (11).

2. The method for manufacturing a fracture internal fixation nail system according to claim 1, characterized in that, This includes heating the top of the first nail head (11) and the bottom of the adhesive end (22) of the second nail head (2), or simultaneously heating the top of the first nail head (11) and the bottom of the adhesive end (22) of the second nail head (2), so that the top of the first nail head (11) and the bottom of the adhesive end (22) of the second nail head (2) melt or the top of the first nail head (11) and the bottom of the adhesive end (22) of the second nail head (2) melt simultaneously; then pressing the bottom of the adhesive end (22) of the second nail head (2) onto the top of the first nail head (11), so that the first nail head (11) is bonded to the adhesive end (22) of the second nail head (2); cooling and solidification to achieve stable bonding of the bone nail (1) and the second nail head (2).

3. The method for manufacturing a fracture internal fixation nail system according to claim 1, characterized in that, The process involves applying a plastic solution to the top of the first nail head (11), then pressing the first nail head (11) with the plastic solution onto the bottom of the adhesive end (22) of the second nail head (2). After the solvent in the plastic solution evaporates, the bone nail (1) and the second nail head (2) are bonded together.

4. The method for manufacturing a fracture internal fixation nail system according to claim 3, characterized in that... The plastic solution is in which plastic is dissolved as a solute in a benign solvent.

5. The method for manufacturing a fracture internal fixation nail system according to claim 1, characterized in that, The process involves partially dissolving the top of the first nail head (11) with a plastic solvent to form a plastic solution on the top of the first nail head (11), using the plastic solution formed on the top of the first nail head (11) as an adhesive, pressing the adhesive end (22) at the bottom of the second nail head (2) onto the top of the first nail head (11), and bonding the bone nail (1) and the second nail head (2) together after the solvent in the plastic solution formed on the top of the first nail head (11) evaporates.

6. A method for manufacturing a fracture internal fixation screw system according to any one of claims 1-5, characterized in that... The bone nail (1) is made of plastic, or is made of plastic composite metal, metal oxide, or inorganic salt, wherein the mass percentage of plastic material is 10.0% to 99.9%.

7. The method for manufacturing an internal fixation bone screw system for fractures according to claim 6, wherein the metal is stainless steel, titanium alloy, iron, tantalum, or magnesium-aluminum alloy; the metal oxide is iron carbide or iron nitride; the inorganic salt is hydroxyapatite or tricalcium phosphate; and the plastic material is absorbable or non-absorbable.

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