CN116687540A - Pressurized degradable bone screw and manufacturing method thereof - Google Patents
Pressurized degradable bone screw and manufacturing method thereof Download PDFInfo
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- CN116687540A CN116687540A CN202310987773.2A CN202310987773A CN116687540A CN 116687540 A CN116687540 A CN 116687540A CN 202310987773 A CN202310987773 A CN 202310987773A CN 116687540 A CN116687540 A CN 116687540A
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- degradable bone
- degradable
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- 210000000988 bone and bone Anatomy 0.000 title claims abstract description 176
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 18
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 59
- 230000035876 healing Effects 0.000 claims abstract description 22
- 241000587161 Gomphocarpus Species 0.000 claims abstract description 5
- 238000005553 drilling Methods 0.000 claims abstract description 5
- 230000000149 penetrating effect Effects 0.000 claims abstract description 5
- 229910052749 magnesium Inorganic materials 0.000 claims description 53
- 239000011777 magnesium Substances 0.000 claims description 53
- 229910052751 metal Inorganic materials 0.000 claims description 50
- 239000002184 metal Substances 0.000 claims description 50
- 238000000137 annealing Methods 0.000 claims description 46
- 230000006835 compression Effects 0.000 claims description 38
- 238000007906 compression Methods 0.000 claims description 38
- 238000005096 rolling process Methods 0.000 claims description 34
- 238000004321 preservation Methods 0.000 claims description 12
- 238000003780 insertion Methods 0.000 claims description 2
- 230000037431 insertion Effects 0.000 claims description 2
- 230000002349 favourable effect Effects 0.000 abstract description 3
- 208000010392 Bone Fractures Diseases 0.000 description 72
- 230000000694 effects Effects 0.000 description 18
- 230000015556 catabolic process Effects 0.000 description 17
- 238000006731 degradation reaction Methods 0.000 description 17
- 238000000034 method Methods 0.000 description 11
- 238000005452 bending Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- 239000007857 degradation product Substances 0.000 description 4
- 238000010030 laminating Methods 0.000 description 4
- 239000007769 metal material Substances 0.000 description 4
- 229910000531 Co alloy Inorganic materials 0.000 description 3
- 229910001069 Ti alloy Inorganic materials 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 2
- 229910000861 Mg alloy Inorganic materials 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 2
- -1 hydroxyl ions Chemical class 0.000 description 2
- 229910001425 magnesium ion Inorganic materials 0.000 description 2
- 230000004060 metabolic process Effects 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 239000011358 absorbing material Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
Abstract
The invention relates to the technical field of medical instruments, and discloses a pressurizing degradable bone screw and a manufacturing method thereof. The bone screw is made of magnesium metal and comprises a split screw rod and a nut, wherein a first external thread is arranged on the screw rod in a penetrating way along the length direction of the screw rod, and a nail head for drilling into a bone is arranged at the head of the screw rod; the nut is provided with second external screw thread, and the second external screw thread is used for threaded connection to the afterbody of screw rod, and the external diameter of the part of not setting up the second external screw thread on the nut is greater than the external diameter of screw rod, and the spiral direction of second external screw thread is opposite with the spiral direction of first external screw thread. The bone screw is favorable for being directly metabolized and absorbed by patients, and is not required to be taken out by secondary operation; simultaneously, the bone screw adopts a split type structure of the screw rod and the screw cap, ensures that under the double functions of forward screw drilling of the screw rod into the bone and reverse screw screwing of the screw cap into the screw rod, two bone surfaces at the fracture surface are mutually abutted and attached, and can improve the healing rate of the fracture surface.
Description
Technical Field
The invention relates to the technical field of medical instruments, in particular to a pressurizing degradable bone screw and a manufacturing method thereof.
Background
Bone screws are internal fixation devices for bone fractures, which can be used alone to align and stabilize the fracture surface. The existing bone screw is generally made of metal materials such as pure titanium, titanium alloy, cobalt-based alloy, stainless steel and the like, and the metal materials are difficult to degrade and absorb, so that the bone screw needs to be taken out through secondary operation, even some bone screws are difficult to be taken out smoothly due to long-time contact with bones, and the burden and pain of a patient can be increased; in addition, when the existing bone screw is screwed into the fracture surface, the existing bone screw is of an integrated structure, and the whole bone screw has only one acting force on the fracture surface, so that the close fit between two bone surfaces at the fracture surface can not be ensured, and the healing rate of the fracture surface is influenced.
In addition, the degradation rate is faster because of the poor mechanical property of the easily degradable bone screw; after the bone screw is implanted into the fracture part of a patient, the bone screw cannot be guaranteed not to be obviously degraded before the fracture surface heals, and the bone screw cannot be guaranteed to provide continuous and effective fixing and pressurizing effects on the fracture surface, so that the healing of the fracture surface is affected.
Disclosure of Invention
One object of the present invention is to propose a compression degradable bone screw which is easily degraded to be directly metabolized and absorbed by the patient, and which is capable of making the two bone faces of the fracture face closely fit, accelerating the healing rate of the fracture face.
To achieve the purpose, the invention adopts the following technical scheme:
a compression degradable bone screw made of metallic magnesium, the compression degradable bone screw comprising:
the screw rod is provided with a first external thread in a penetrating manner along the length direction, and the head of the screw rod is provided with a nail head for drilling into bones;
the nut is provided with a second external thread which is used for being connected to the tail part of the screw rod in a threaded mode, the outer diameter of the part, on which the second external thread is not arranged, of the nut is larger than the outer diameter of the screw rod, and the spiral direction of the second external thread is opposite to the spiral direction of the first external thread; the compression degradable bone screw adopts a split structure of a screw rod and a screw cap, so that under the dual effects that the screw rod is positively screwed into a bone and the screw cap is reversely screwed into the screw rod, two bone surfaces at a fracture surface are mutually abutted and attached, and the healing rate of the fracture surface is improved.
Further, the pressurizing degradable bone screw is manufactured through multiple times of annealing and multiple times of rolling, so that the grain size of the pressurizing degradable bone screw is a preset grain size, the tensile strength of the pressurizing degradable bone screw is a preset tensile strength, and the bending strength of the pressurizing degradable bone screw is a preset bending strength; so as to refine the grain size of the pressurizing degradable bone screw and improve the mechanical properties of the pressurizing degradable bone screw such as tensile strength and bending strength.
Further, the preset grain size is matched with the healing period of the fracture surface; so as to ensure that the compression degradable bone screw does not have obvious degradation phenomenon before fracture surface healing, and prolong the degradation period of the compression degradable bone screw, thereby ensuring that the compression degradable bone screw can always provide fixing and compression effects on fracture surfaces.
Further, a plurality of rotation stopping grooves are formed in the first external thread, and the rotation stopping grooves are used for preventing the screw rod from reversely unscrewing relative to the bone; so as to avoid the problem that the screw rod is loosened reversely relative to the fracture surface due to the movement of a patient and the reverse screwing of the screw cap into the screw rod, and ensure the stability and fixation of the screw rod in the fracture surface.
Further, the rotation stopping groove is provided with an arc-shaped surface, the arc-shaped surface extends downwards in an inclined mode in the screwing direction of the screw rod, and an included angle between the arc-shaped surface and the horizontal plane is 25-35 degrees; so as to ensure that the anti-reverse loosening effect of the anti-rotation groove on the screw is better while ensuring that the anti-rotation groove does not interfere the operation of forward screwing the screw into the bone.
Further, in a direction from the head of the screw to the tail of the screw, the tooth thickness of the first external thread is gradually increased; the screw rod is provided with a certain pressure on the fracture surface when the screw rod is gradually screwed into the bone, so that two bone surfaces at the fracture surface can be mutually close to each other for lamination, and the healing rate of the fracture surface is further improved; and can ensure that the screw rod is firmly fixed in the fracture surface.
Further, a first rotating groove is formed in the inner side of the screw rod, the first rotating groove extends from the tail portion of the screw rod to the middle portion, and the first rotating groove is used for being inserted into a screwing device.
Further, a tail groove is formed in the inner side of the tail portion of the screw, an inner thread matched with the second outer thread is formed in the inner wall surface of the tail groove, the tail groove is communicated with the first rotating groove, the inner diameter of the tail groove is larger than that of the first rotating groove, and the depth of the tail groove is matched with the length of the portion, provided with the second outer thread, of the screw cap.
Another object of the present invention is to provide a method for manufacturing a compression degradable bone screw, which can make the compression degradable bone screw with a slower degradation rate, so as to ensure that the degradation period and the mechanical property of the compression degradable bone screw meet the requirements.
To achieve the purpose, the invention adopts the following technical scheme:
a method of manufacturing a compression degradable bone screw for manufacturing a compression degradable bone screw as described above, comprising the steps of:
s1: selecting a cylindrical metal magnesium bar;
s2: annealing and rolling the metal magnesium bar for multiple times; the annealing and rolling sequence is that the first-stage annealing and the second-stage annealing are sequentially carried out and then the rolling is carried out; the temperature of the first-stage annealing is 100-110 ℃, the heat preservation time is 5-6 min, the temperature of the second-stage annealing is 160-170 ℃, the heat preservation time is 8-10 min, and the deformation rate of the metal magnesium bar is 5-10% during each rolling;
s3: the metal magnesium bar obtained in the step S2 is manufactured into the screw rod and the screw cap of the pressurizing degradable bone screw in a core-moving processing mode; the pressurizing degradable bone screw with a split structure can be manufactured, and the degradation period and the mechanical property of the pressurizing degradable bone screw are good.
Further, in step S2, before rolling the metal magnesium bar, the first-stage annealing and the second-stage annealing are performed in sequence each time, and the rolling time is 10min-11min each time; so as to ensure that annealing is required before each rolling, thereby ensuring that the obtained magnesium metal bar has finer grain size and better mechanical property.
The beneficial effects of the invention are as follows:
the whole pressurizing degradable bone screw is made of metal magnesium, namely the pressurizing degradable bone screw is made of pure magnesium, so that the pressurizing degradable bone screw has better biocompatibility, compared with the pressurizing degradable bone screw made of magnesium alloy, the pressurizing degradable bone screw is simple in component, and the degradation products are magnesium ions, hydroxyl ions and hydrogen, so that the pressurizing degradable bone screw is less in degradation products, is favorable for metabolism and absorption by patients, does not need to be taken out by secondary operation, and reduces the burden and pain of the patients; meanwhile, a first external thread is arranged on the screw rod of the pressurizing degradable bone screw in a penetrating way along the length direction of the screw rod, namely, a full thread structure is arranged on the screw rod, and a second external thread is arranged on the screw cap, wherein the second external thread is used for being connected to the tail part of the screw rod in a threaded way, and the spiral direction of the second external thread is opposite to that of the first external thread; when the screw is screwed into the fracture surface, the screw cap is screwed to the tail part of the screw in the direction opposite to the screwing direction of the screw, so that the screw cap can provide an upward lifting force for the screw in the process of reversely screwing the screw cap; simultaneously, because the screw rod can produce a decurrent pressure to the fracture face when forward screw in fracture face to can make the screw rod can promote two bone faces of fracture face department and draw close the laminating each other voluntarily under the effect of ascending pulling force and decurrent pressure, so that two bone faces can laminate comparatively closely, and then realize the pressurization laminating effect to the fracture face, and then can accelerate the healing rate of fracture face.
And, make the external diameter of the part not provided with the second external screw thread on the nut greater than the external diameter of the screw rod; so that the screw rod can be prevented from sinking into the bone, especially into cancellous bone, by the nut, and the use reliability of the pressurized degradable bone screw is ensured.
The metal magnesium bar is annealed and rolled for multiple times, namely, the metal magnesium bar is annealed for the first stage and annealed for the second stage in sequence, the temperature of the first stage is 100-110 ℃, the heat preservation time is 5-6 min, the temperature of the second stage is 160-170 ℃, the heat preservation time is 8-10 min, the deformation rate of the metal magnesium bar is 5-10% during each rolling, so that the metal magnesium bar subjected to multiple repeated annealing and multiple repeated rolling has better mechanical compatibility, the tensile strength of the manufactured pressurizing degradable bone screw is ensured to be preset tensile strength, and the problem that the pressurizing degradable bone screw is pulled out from a fracture surface due to the movement of a patient is avoided, so that the pressurizing degradable bone screw can be stably arranged at the fracture surface; meanwhile, the bending strength of the manufactured pressurizing degradable bone screw is preset, so that the problems that the pressurizing degradable bone screw is broken and bending cracks are caused to the pressurizing degradable bone screw due to movement of a patient are avoided, the pressurizing degradable bone screw is prevented from being bent and damaged in the movement process of the patient, and the pressurizing degradable bone screw can provide stable fixing effect on a fracture surface; moreover, as the crystal grains in the metal magnesium bar can be rolled when the metal magnesium bar is rolled, the crystal grains in the pressurizing degradable bone screw are smaller and more in quantity, so that the degradation rate of the pressurizing degradable bone screw in a patient body can be slowed down, the degradation period of the pressurizing degradable bone screw is prolonged, the pressurizing degradable bone screw is ensured not to be obviously degraded before the fracture surface heals, and the pressurizing degradable bone screw can provide continuous fixing and pressurizing attaching effects for the fracture surface.
Drawings
FIG. 1 is a schematic view of the structure of a pressurized degradable bone screw provided by the present invention;
FIG. 2 is a cross-sectional view taken along the A-A plane of FIG. 1;
FIG. 3 is a schematic view of the structure of the screw provided by the invention;
FIG. 4 is a cross-sectional view of the B-B plane of FIG. 3;
FIG. 5 is a schematic view of the structure of the nut provided by the present invention;
FIG. 6 is an elevation view of a nut provided by the present invention;
FIG. 7 is a cross-sectional view of the C-C plane of FIG. 6;
fig. 8 is a flow chart of a method of manufacturing a compression degradable bone screw according to the present invention.
Reference numerals:
1-a screw; 11-a first external thread; 111-tooth thickness; 12-a rotation stopping groove; 121-an arc surface; 13-a first swirl slot; 14-tail groove; 15-internal threads;
2-a nut; 21-a second external thread; 22-second rotating groove.
Detailed Description
In order to make the technical problems solved, the technical scheme adopted and the technical effects achieved by the invention more clear, the technical scheme of the invention is further described below by a specific embodiment in combination with the attached drawings.
In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; 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.
At present, bone screws are generally made of metal materials such as pure titanium, titanium alloy, cobalt-based alloy, stainless steel and the like, and because the metal materials are non-degradable absorbing materials, the bone screws need to be taken out through secondary operation, even some bone screws are difficult to be taken out smoothly due to long-time contact with bones, and the burden and pain feeling of patients can be increased.
Therefore, the embodiment provides a pressurizing and degradable bone screw which is made of metal magnesium, even if the pressurizing and degradable bone screw is made of pure magnesium, the pressurizing and degradable bone screw has better biocompatibility; compared with the pressurizing degradable bone screw made of pure titanium, titanium alloy, cobalt-based alloy, stainless steel and other materials, the pressurizing degradable bone screw can better promote fracture surface healing, does not need secondary operation to take out the pressurizing degradable bone screw, and reduces burden and pain of patients; in addition, compared with the pressurizing degradable bone screw made of magnesium alloy, the pressurizing degradable bone screw in the embodiment has the advantages that the components are simple, the degradation mechanism is clear and definite, the degradation products are magnesium ions, hydroxyl ions and hydrogen, the degradation products are few, and the pressurizing degradable bone screw is more favorable for being metabolized and absorbed by patients, so that the burden and pain of the patients can be further reduced, and in the embodiment, the pressurizing degradable bone screw is made of 99.98-99.99% of pure magnesium.
Because the existing pressurizing degradable bone screw is generally of an integrated structure, when the pressurizing degradable bone screw is screwed into a fracture surface, the whole pressurizing degradable bone screw has only one acting force on the fracture surface, so that the close fit between two bone surfaces at the fracture surface can not be ensured, and the healing rate of the fracture surface is influenced.
To this end, as shown in fig. 1, the compression degradable bone screw comprises a shank 1 and a nut 2; the screw rod 1 is provided with a first external thread 11 in a penetrating manner along the length direction, namely, the screw rod 1 is provided with a full thread structure so as to ensure the stability of screwing the screw rod 1 into a fracture surface; the head of the screw rod 1 is provided with a nail head for drilling into bones, so that the screw rod 1 is driven by the nail head to be smoothly screwed into a fracture surface; the second external thread 21 is arranged on the nut 2, the second external thread 21 is used for being connected to the tail part of the screw 1 in a threaded mode, the outer diameter of the part, on which the second external thread 21 is not arranged, of the nut 2 is larger than the outer diameter of the screw 1, the spiral direction of the second external thread 21 is opposite to that of the first external thread 11, the depth of the first external thread 11 relative to the outer wall surface of the screw 1 is 0.5mm, and the screw pitch is 1mm specifically.
In contrast to the prior art compression degradable bone screw of unitary construction, the compression degradable bone screw is provided in this embodiment as a split construction comprising a screw 1 and a nut 2; when the screw 1 is screwed into the fracture surface, the screw cap 2 is screwed to the tail of the screw 1 in the direction opposite to the screwing direction of the screw 1, so that the screw cap 2 can provide an upward lifting force for the screw 1 in the process of reversely screwing the screw cap 2; simultaneously, because screw rod 1 can produce a decurrent pressure to the fracture face when forward screw in fracture face to can make screw rod 1 can promote two bone faces of fracture face department and draw close the laminating each other voluntarily under the effect of ascending pulling force and decurrent pressure, so that two bone faces can laminate comparatively closely, and then realize the pressurization laminating effect to the fracture face, and then can accelerate the healing rate of fracture face. In this embodiment, the screw 1 is screwed into the fracture surface in the forward direction, and correspondingly, the nut 2 is screwed into the tail of the screw 1 in the reverse direction.
Wherein, as shown in fig. 1, the outer diameter of the portion of the nut 2 not provided with the second external thread 21 is made larger than the outer diameter of the screw rod 1, so that the screw rod 1 can be prevented from sinking into the bone, especially into the cancellous bone, by the nut 2, and the use reliability of the pressurized degradable bone screw is ensured.
Further, the pressurizing and degradable bone screw is manufactured through multiple annealing and multiple rolling, so that the grain size of the pressurizing and degradable bone screw is the preset grain size, namely, the pressurizing and degradable bone screw is rolled, so that the grains in the pressurizing and degradable bone screw are smaller and more in number, the degradation rate of the pressurizing and degradable bone screw in a patient body can be slowed down, the degradation period of the pressurizing and degradable bone screw is prolonged, the pressurizing and degradable bone screw is ensured not to be obviously degraded before fracture surface healing, and the pressurizing and degradable bone screw can provide continuous fixing and pressurizing fit effects on the fracture surface in the fracture surface healing period.
The healing period of the fracture surface can be specifically within 3-6 months, the preset grain size is matched with the healing period of the fracture surface, that is, the preset grain size is matched with the degradation period of the pressurizing degradable bone screw, correspondingly, the degradation period of the pressurizing degradable bone screw is more than 3-6 months, that is, the pressurizing degradable bone screw does not have obvious degradation within 3-6 months; in the healing period of the fracture surface, the pressurized degradable bone screw does not have obvious degradation phenomenon; after the healing period of the fracture surface has elapsed, the pressurized degradable bone screw begins to undergo significant degradation until it is completely degraded to be absorbed by the patient's metabolism.
In addition, the compression degradable bone screw is manufactured through multiple annealing and multiple rolling, and the tensile strength of the compression degradable bone screw is also the preset tensile strength, so that the problem that the compression degradable bone screw is pulled out from a fracture surface due to the movement of a patient can be avoided, and the compression degradable bone screw can be stably arranged at the fracture surface; meanwhile, the bending strength of the pressurizing degradable bone screw can be preset, so that the problems that the pressurizing degradable bone screw is broken and bending cracks are caused due to movement of a patient are avoided, the pressurizing degradable bone screw is prevented from being bent and damaged in the movement process of the patient, and the pressurizing degradable bone screw can provide stable fixing effect on a fracture surface. Wherein the preset tensile strength is 220N-240N, and the preset bending strength is 280N-300N.
Further, as shown in fig. 1 to 3, a plurality of rotation stopping grooves 12 are provided on the first external thread 11, the rotation stopping grooves 12 are used for preventing the screw 1 from reversely unscrewing relative to the bone, that is, the rotation stopping grooves 12 are a section of groove on the first external thread 11, when the screw 1 is screwed and fixed in a fracture surface, since the bone has a certain extrusion in the process of screwing in through the screw 1, at the rotation stopping grooves 12, the bone can rebound in a part of the groove due to the existence of the groove, so that the problem of preventing the screw 1 and the whole pressurizing degradable bone screw from reversely rotating in the bone can be played through the rotation stopping grooves 12, and the fixation effect of the screw 1 in the bone is ensured; and due to the arrangement of the rotation stopping groove 12, the screw 1 can not rotate reversely when the screw cap 2 is screwed into the tail part of the screw 1, the reliability of the screw 1 in the screwing process of the screw cap 2 is ensured, and the problem that the screw 1 loosens in a bone surface can not occur.
Specifically, as shown in fig. 1 to 3, the rotation stopping groove 12 is provided with an arc-shaped surface 121, the arc-shaped surface 121 extends downwards in an inclined manner towards the screwing direction of the screw 1, and an included angle between the arc-shaped surface 121 and a horizontal plane is 25 ° -35 °, so that on one hand, bone can be ensured to rebound on a part of the arc-shaped surface 121, and the reverse loosening prevention effect of the rotation stopping groove 12 on the screw 1 is ensured to be better; on the other hand, the screw 1 can be smoothly screwed into the bone by ensuring that the rotation stopping groove 12 does not interfere the operation of screwing the screw 1 into the bone, so that the pain of a patient caused by the rotation stopping groove 12 when the screw 1 is screwed into the bone can be avoided. In this embodiment, the angle between the arc-shaped surface 121 and the horizontal plane is 35 °.
In this embodiment, as shown in fig. 1 to 3, the number of the rotation stopping grooves 12 is three, and the three rotation stopping grooves 12 are respectively located at the head, the middle and the tail of the screw 1, so that the reverse rotation of the screw 1 in the bone can be limited from three positions of the screw 1, and thus the anti-loosening effect on the screw 1 can be better. Wherein, three anti-rotation grooves 12 are positioned on the same straight line, the cutting depth of the anti-rotation grooves 12 on the first external thread 11 is 0.5mm, and one anti-rotation groove 12 cuts at least one first external thread 11.
Further, as shown in fig. 1 to 3, the tooth thickness 111 of the first external thread 11 gradually increases in the direction from the head of the screw 1 to the tail of the screw 1 along the length of the screw 1, that is, the tooth thickness 111 of the first external thread 11 located at the head of the screw 1 is smaller and the tooth thickness 111 of the first external thread 11 located at the tail of the screw 1 is larger. In this embodiment, the tooth thickness 111 of the first external thread 11 gradually increases from 0.1mm to 0.3mm from the head to the tail of the screw 1.
By forming the first external thread 11 into a gradual tooth thickness configuration, the first external thread 11 having the smaller tooth thickness 111 can be more easily screwed into the bone when the compression degradable bone screw is gradually screwed into the bone; on the other hand, as the tooth thickness 111 of the first external thread 11 at the tail part of the screw rod 1 is larger, even if the first external thread 11 with larger tooth thickness 111 gradually applies larger pressurizing force to the fracture surface, the first external thread 11 can gradually pressurize the fracture surface, so that the fracture surface can be driven to be mutually extruded and closed, the two bone surfaces are ensured to be better mutually attached, and the healing rate of the fracture surface is further improved; and can ensure a good fixing effect between the screw 1 and the bone.
Further, as shown in fig. 2 and 4, a first rotating groove 13 is provided on the inner side of the screw 1, the first rotating groove 13 extends from the tail portion of the screw 1 to the middle portion, and a matched screwing device is inserted into the first rotating groove 13, so that the screw 1 is screwed into the bone through the screwing device, and the screw 1 is screwed into the fracture surface easily and conveniently. The screw-in device is of a common screw-in structure in the prior art.
In order to ensure the stability of the screwing of the screw 1 by the screwing device, in this embodiment, the depth of the first rotary groove 13 is half of the length of the entire screw 1, and the diameter of the circumscribed circle of the first rotary groove 13 is 2mm. The cross-sectional shape of the first rotating groove 13 is quadrangular, and the cross-sectional shape of the first rotating groove 13 may be circular or other shapes, which is not limited herein, so long as the screwing device is ensured to be capable of being inserted into the first rotating groove 13 in a matching manner.
Specifically, as shown in fig. 2 and 4, a tail groove 14 is provided on the inner side of the tail portion of the screw 1, an internal thread 15 that matches the second external thread 21 is provided on the inner wall surface of the tail groove 14, and the depth of the tail groove 14 matches the length of the portion of the nut 2 on which the second external thread 21 is provided; the second external thread 21 is in threaded connection with the internal thread 15, so that the nut 2 can be fixedly arranged on the screw 1; the tail groove 14 is communicated with the first rotating groove 13, and the inner diameter of the tail groove 14 is larger than that of the first rotating groove 13. Wherein the arrangement depth of the tail groove 14 in the screw 1 is 4mm.
Specifically, when the fracture surface is fixed, the matched screw-in device is inserted into the first rotating groove 13 of the screw rod 1, and the screw rod 1 is screwed into the bone clockwise by screwing the screw-in device, and at the moment, the screw rod 1 penetrates through the whole fracture surface; after that, the screwing device is taken out again, and the screw cap 2 is screwed anticlockwise, so that the screw cap 2 is screwed into the tail groove 14 at the tail part of the screw rod 1, and the connection between the screw cap 2 and the screw rod 1 is realized. Wherein the length of the whole screw cap 2 is 7mm.
Further, as shown in fig. 5 to 7, a second rotating groove 22 is provided on the inner side of the end of the nut 2 far away from the screw 1, and the second rotating groove 22 is used for plugging in a matched instrument, so that the nut 2 is driven to rotate by rotating the instrument, and the nut 2 is easy and convenient to rotate. The apparatus may be a wrench, and the specific structure of the apparatus is not limited. The cross section of the second rotating groove 22 is in a hexagonal quincuncial shape, so that the insertion between the instrument and the second rotating groove 22 is relatively tight, and the instrument cannot rotate in the second rotating groove 22 in the screwing process. Here, the specific shape of the second whirling groove 22 is not limited.
Because the pressurizing degradable bone screw made of pure magnesium has poor mechanical property and high degradation rate; after the pressurizing degradable bone screw is implanted into the fracture part of a patient, the pressurizing degradable bone screw cannot be guaranteed not to be obviously degraded before the fracture surface heals, and the pressurizing degradable bone screw cannot be guaranteed to provide continuous and effective fixing and pressurizing effects on the fracture surface, so that the healing of the fracture surface is affected.
In order to solve the above problems, the present embodiment also provides a method for manufacturing the compression degradable bone screw, which is used for manufacturing the compression degradable bone screw, so that the manufactured compression degradable bone screw can have better fixing and compression fitting effects on the fracture surface in the whole fracture surface healing period.
Specifically, as shown in fig. 8, the method of manufacturing the pressurized degradable bone screw comprises the steps of: s1: selecting a cylindrical metal magnesium bar; s2: annealing and rolling the metal magnesium bar for multiple times to ensure that the grain size and the mechanical property of the metal magnesium bar can meet the requirements; the annealing and rolling sequence is that the first-stage annealing and the second-stage annealing are sequentially carried out and then the rolling is carried out; the annealing temperature in the first stage is 100-110 ℃, the heat preservation time is 5-6 min, the annealing temperature in the second stage is 160-170 ℃, the heat preservation time is 8-10 min, and the deformation rate of the metal magnesium bar is 5-10% during each rolling; s3: and (2) manufacturing the metal magnesium bar obtained in the step (S2) into a pressurizing degradable bone screw by adopting a core-moving processing mode, namely processing the annealed and rolled metal magnesium bar into a screw rod 1 and a screw cap 2 with a split structure.
The deformation rate of the metal magnesium bar is specifically calculated according to the formula (S1-S2)/S1, S1 is specifically the maximum cross-sectional area of the metal magnesium bar, and S2 is specifically the minimum cross-sectional area of the metal magnesium bar.
The number of times of annealing and rolling the metal magnesium bar is not limited, and the screw 1 and the screw cap 2 made of the metal magnesium bar can meet the requirements of grain size and mechanical property.
Specifically, in step S2, the first-stage annealing and the second-stage annealing are required to be performed in sequence each time before the metal magnesium rod is rolled, and the metal magnesium rod is required to be rolled immediately after the second-stage annealing, and the rolling time is 10min-11min each time.
Specifically, in the step S1, the length of the metal magnesium bar is specifically 1m, the diameter is 8.5mm, and the magnesium content of the metal magnesium bar is 99.98%; in the step S2, the annealing temperature in the first stage is specifically 100 ℃, the heat preservation time is specifically 5min, the annealing temperature in the second stage is specifically 160 ℃, and the heat preservation time is specifically 8min; also, in the four-pass rolling process, the diameter change of the metal magnesium rod is, in turn, 8.2mm from 8.5mm, 7.8mm from 8.2mm from 7.8mm, 7.3mm from 7.8mm, and 7.0mm from 7.3mm, that is, the maximum outer diameter of the screw 1 made in this embodiment is specifically 7.0mm±0.5mm, and the diameter of the portion of the screw 1 where the first external thread 11 is not provided is specifically 4.5mm. Wherein, through the repeated annealing and rolling processes, the tensile strength of the metal magnesium bar is 220-240N, the elongation of the metal magnesium bar is 12% -15%, and even if the bending strength of the metal magnesium bar is 280-300N.
The specific manufacturing process of the manufacturing method of the pressurized degradable bone screw in the embodiment is as follows:
firstly, providing a cylindrical metal magnesium bar, wherein the length of the metal magnesium bar is 1m, and the diameter of the metal magnesium bar is 8.5mm; and then sequentially carrying out first-stage annealing with the annealing temperature of 100 ℃ and the heat preservation time of 5min and second-stage annealing with the annealing temperature of 160 ℃ and the heat preservation time of 8min on the metal magnesium bar, and immediately rolling the metal magnesium bar for the first time after the second-stage annealing is finished, and rolling the diameter of the metal magnesium bar from 8.5mm to 8.2mm so as to finish the first annealing and the first rolling.
Then sequentially carrying out first-stage annealing and second-stage annealing on the metal magnesium bar subjected to the first rolling, and carrying out second rolling on the metal magnesium bar by a vertical horse after the second-stage annealing is finished, and rolling the diameter of the metal magnesium bar from 8.2mm to 7.8mm so as to finish the second annealing and the second rolling; the above-mentioned process was repeated until the diameter of the metal magnesium bar was rolled to 7mm, thereby completing the processes of multiple annealing and multiple rolling of the metal magnesium bar.
Finally, the metal magnesium bar subjected to the annealing and rolling for multiple times is subjected to numerical control processing, namely, a core walking machine is used for processing the metal magnesium bar into the screw rod 1 and the screw cap 2 with the split structures, so that the manufacturing process of the whole pressurizing degradable bone screw is completed.
The foregoing is merely exemplary of the present invention, and those skilled in the art should not be considered as limiting the invention, since modifications may be made in the specific embodiments and application scope of the invention in light of the teachings of the present invention.
Claims (10)
1. A compression degradable bone screw, characterized in that the compression degradable bone screw is made of metallic magnesium, the compression degradable bone screw comprising:
the screw rod (1), the screw rod (1) is provided with a first external thread (11) in a penetrating way along the length direction, and the head of the screw rod (1) is provided with a nail head for drilling into a bone;
the nut (2), be provided with second external screw thread (21) on nut (2), second external screw thread (21) are used for threaded connection to the afterbody of screw rod (1), the external diameter of the part of nut (2) not setting up second external screw thread (21) is greater than the external diameter of screw rod (1), just the spiral direction of second external screw thread (21) with the spiral direction of first external screw thread (11) is opposite.
2. The compression degradable bone screw of claim 1, wherein the compression degradable bone screw is made by a plurality of anneals and a plurality of rolls such that the grain size of the compression degradable bone screw is a preset grain size, and such that the tensile strength of the compression degradable bone screw is a preset tensile strength, and the flexural strength of the compression degradable bone screw is a preset flexural strength.
3. The pressurized degradable bone screw of claim 2, wherein the predetermined grain size matches a healing cycle of the fracture surface.
4. A compression degradable bone screw according to any one of claims 1-3, characterized in that the first external thread (11) is provided with a plurality of rotation stopping grooves (12), the rotation stopping grooves (12) being adapted to prevent the screw (1) from unscrewing in opposite directions relative to the bone.
5. The compression degradable bone screw according to claim 4, characterized in that the rotation stopping groove (12) has an arc-shaped surface (121), the arc-shaped surface (121) extends obliquely downwards in the screwing direction of the screw (1), and the angle between the arc-shaped surface (121) and the horizontal plane is 25 ° -35 °.
6. A pressurized degradable bone screw according to any of claims 1-3, characterized in that the tooth thickness (111) of the first external thread (11) increases gradually in the direction from the head of the screw (1) to the tail of the screw (1).
7. A pressurized degradable bone screw according to any of claims 1-3, characterized in that the inner side of the screw (1) is provided with a first turning groove (13), the first turning groove (13) extending from the tail of the screw (1) towards the middle, the first turning groove (13) being intended for insertion into a screw-in device.
8. The pressurized degradable bone screw according to claim 7, characterized in that a tail groove (14) is provided on the inner side of the tail of the screw (1), an inner wall surface of the tail groove (14) is provided with an inner thread (15) matched with the second outer thread (21), the tail groove (14) is communicated with the first rotating groove (13), the inner diameter of the tail groove (14) is larger than the inner diameter of the first rotating groove (13), and the depth of the tail groove (14) is matched with the length of the portion of the nut (2) provided with the second outer thread (21).
9. A method of manufacturing a compression degradable bone screw according to any one of claims 1 to 8, comprising the steps of:
s1: selecting a cylindrical metal magnesium bar;
s2: annealing and rolling the metal magnesium bar for multiple times; the annealing and rolling sequence is that the first-stage annealing and the second-stage annealing are sequentially carried out and then the rolling is carried out; the temperature of the first-stage annealing is 100-110 ℃, the heat preservation time is 5-6 min, the temperature of the second-stage annealing is 160-170 ℃, the heat preservation time is 8-10 min, and the deformation rate of the metal magnesium bar is 5-10% during each rolling;
s3: and (2) manufacturing the screw rod (1) and the nut (2) of the pressurizing degradable bone screw by adopting a core-moving processing mode for the metal magnesium bar obtained in the step (2).
10. The method of manufacturing a compression degradable bone screw according to claim 9, wherein in step S2, the first stage annealing and the second stage annealing are sequentially performed each time before the metal magnesium rod is rolled, and each rolling time is 10min to 11min.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310987773.2A CN116687540A (en) | 2023-08-08 | 2023-08-08 | Pressurized degradable bone screw and manufacturing method thereof |
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| CN202310987773.2A CN116687540A (en) | 2023-08-08 | 2023-08-08 | Pressurized degradable bone screw and manufacturing method thereof |
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| CN202410155792.3A Division CN118000877A (en) | 2023-08-08 | Degradable bone screw for promoting fracture surface healing and preparation method thereof |
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| CN116687540A true CN116687540A (en) | 2023-09-05 |
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| CN2640426Y (en) * | 2003-06-24 | 2004-09-15 | 中南大学湘雅医院 | Locking partially threaded screw for spongy bone |
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| CN210749453U (en) * | 2017-07-25 | 2020-06-16 | 江苏百易得医疗科技有限公司 | Hollow bone screw |
| CN115916078A (en) * | 2020-04-09 | 2023-04-04 | 洛克因公司 | Bone anchoring implant with cortical stabilization |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5498265A (en) * | 1991-03-05 | 1996-03-12 | Howmedica Inc. | Screw and driver |
| CN2640426Y (en) * | 2003-06-24 | 2004-09-15 | 中南大学湘雅医院 | Locking partially threaded screw for spongy bone |
| CN104328318A (en) * | 2014-10-20 | 2015-02-04 | 东北大学 | Preparation method of high-corrosion-resistance biodegradable magnesium alloy |
| CN210749453U (en) * | 2017-07-25 | 2020-06-16 | 江苏百易得医疗科技有限公司 | Hollow bone screw |
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