Manufacturing method of shape memory alloy artificial nucleus pulposus prosthesis

Abstract

The invention provides a method for manufacturing a shape memory alloy artificial nucleus prosthesis, which comprises the following steps of: manufacturing a shape memory alloy wire from a shape memory alloy plate based on a metal drawing process, winding the shape memory alloy wire into a shape memory alloy spring through a spring manufacturing process, and manufacturing the shape memory alloy artificial nucleus prosthesis. A shape memory alloy spring is wound into a cylinder-like elastic body in a cylindrical cavity of a first mold in a tiling, stacking and winding mode, the cylinder-like elastic body is sequentially pressed, heated and subjected to heat preservation to form a solid cylinder-like elastic body, and the solid cylinder-like elastic body is sequentially pressed, heated and subjected to heat preservation to form a second elliptic cylindrical nucleus pulposus prosthesis; the porosity of the second elliptic cylindrical nucleus pulposus prosthesis is greater than 80%, and after the second elliptic cylindrical nucleus pulposus prosthesis is cooled, the second elliptic cylindrical nucleus pulposus prosthesis is pressed into the shape memory alloy artificial nucleus pulposus prosthesis with the deformation quantity not less than 30%. The technical problems that in the prior art, an artificial nucleus pulposus prosthesis is large in elastic modulus, poor in mechanical performance, poor in oxidation resistance, poor in abrasion resistance and large in size are solved.

Description

Technical Field

[0001] The invention relates to the technical field of medical implant devices, and in particular to a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis. Background Art

[0002] In modern society, most people need to sit in front of computers for a long time, which leads to an increasing incidence of lumbar disc herniation. Lumbar disc herniation mainly refers to a series of signs caused by the rupture of the lumbar annulus fibrosus and the protrusion of the nucleus pulposus, which compresses and stimulates the sciatic nerve on one or both sides at the corresponding level.

[0003] Nucleus pulposus replacement is an effective method for treating lumbar disc herniation, and the ideal artificial nucleus pulposus must meet the following requirements: 1. It has good biocompatibility and biodurability, will not degrade or produce rejection reactions in the body, and has low wear and low consumption; 2. The stiffness and mobility of the prosthesis are within the normal physiological range, and can withstand endurance fatigue tests and will not be squeezed out in the body; 3. It can resist stress, maintain the height of the intervertebral space and have a buffering effect; 4. It has good compliance, moderate hardness, and can maintain its shape while evenly transmitting stress; 5. It is easy to insert and has a shape and size that matches the normal nucleus pulposus space; 6. It has a liquid pump function, which can increase the nutrient supply to the remaining nucleus pulposus and the inner annulus fibrosus, so that the annulus fibrosus maintains its biomechanical strength.

[0004] At present, artificial nucleus pulposus prostheses still have the following problems: first, the elastic modulus is too high, which affects the patient's daily life; second, the manufacturing material is high molecular polymer, which leads to poor mechanical properties, antioxidant ability and wear resistance of the artificial nucleus pulposus prosthesis. Long-term use cannot guarantee the effectiveness of use and easily produces debris, causing pain to patients; third, the artificial nucleus pulposus prosthesis is large in size and easily damages the annulus fibrosus during surgical implantation. Summary of the invention

[0005] The purpose of the present invention is to provide a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis, so as to manufacture an artificial nucleus pulposus prosthesis of shape memory alloy, which can solve the technical problems of artificial nucleus pulposus prosthesis in the prior art, such as large elastic modulus, poor mechanical properties, poor oxidation resistance, poor wear resistance and large volume.

[0006] To achieve the above objectives, the present application embodiment adopts the following technical solutions:

[0007] A method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis is used to manufacture a shape memory alloy artificial nucleus pulposus prosthesis, and the method comprises the following steps:

[0008] Based on the metal drawing process, the shape memory alloy sheet is made into a shape memory alloy wire with a desired diameter;

[0009] Through a spring making process, the shape memory alloy wire is wound into a shape memory alloy spring;

[0010] A shape memory alloy spring is wound into a quasi-cylindrical elastic body in a cylindrical cavity of a first mold by a flat-laying and superimposed winding method, wherein the flat-laying and superimposed winding method is as follows: the first end of the shape memory alloy spring is flat-laid on the center of the bottom surface of the cylindrical cavity, and the second end of the shape memory alloy spring is wound toward the cavity wall of the cylindrical cavity in a quasi-helical shape with the central axis of the cylindrical cavity as the center, until the shape memory alloy spring covers the bottom surface of the cylindrical cavity to form a first flat-laid spring layer, the second end of the shape memory alloy spring is raised and wound inwardly toward the central axis of the cylindrical cavity in a quasi-helical shape along the cavity wall of the cylindrical cavity until a second flat-laid spring layer is formed, and the above-mentioned winding process is repeated until the shape memory alloy spring is wound to form an Nth flat-laid spring layer, wherein N is a natural number greater than 1, and the plurality of coils of the upper flat-laid spring layer are all located in the middle of the plurality of pitch spaces of the lower flat-laid spring layer, and the N layers of the flat-laid spring layers constitute the quasi-cylindrical elastic body;

[0011] Putting the first mold and the quasi-cylindrical elastic body into a stamping device, pressing the quasi-cylindrical elastic body into a preliminary solid quasi-cylindrical elastic body, and putting the preliminary solid quasi-cylindrical elastic body and the first mold into an air furnace together, heating them to 37° C. and keeping them warm to shape them into a solid quasi-cylindrical elastic body;

[0012] Putting the solid cylindrical elastic body into the elliptical cylindrical cavity of the second mold, and using the punching equipment to press the solid cylindrical elastic body into a first elliptical cylindrical nucleus pulposus prosthesis;

[0013] Putting the first elliptical cylindrical nucleus pulposus prosthesis and the second mold together into the air furnace, heating to 37° C. and keeping the temperature to shape into a second elliptical cylindrical nucleus pulposus prosthesis, wherein the porosity of the second elliptical cylindrical nucleus pulposus prosthesis is greater than 80%;

[0014] The second elliptical cylindrical nucleus pulposus prosthesis is cooled by liquid nitrogen, and the second elliptical cylindrical nucleus pulposus prosthesis is pressed into a shape memory alloy artificial nucleus pulposus prosthesis with a set deformation amount by the punching equipment, and the set deformation amount is not less than 30%.

[0015] In a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, the process of manufacturing a shape memory alloy sheet into a shape memory alloy wire having an expected diameter based on a metal drawing process includes the following steps:

[0016] Placing the shape memory alloy plate in the air furnace, setting the temperature of the air furnace to 900° C., performing solution treatment for 2 hours, and performing wire cutting on the shape memory alloy plate after the solution treatment to obtain a first shape memory alloy wire with a diameter of 0.8 mm;

[0017] The first end of the first shape memory alloy wire is immersed in a corrosion solution at a uniform speed for 5-30 minutes to obtain a second shape memory alloy wire, wherein the corrosion solution is a mixed solution of hydrofluoric acid, nitric acid and water, and the ratio of the hydrofluoric acid, nitric acid and water is 1:4:20;

[0018] The second shape memory alloy wire is subjected to several cold drawing processes and slitting processes by using a drawing device to obtain a shape memory alloy wire having an expected diameter, wherein in each cold drawing process of the second shape memory alloy wire, the deformation amount of the second shape memory alloy wire is less than 20%, and after each cold drawing process, the second shape memory alloy wire is subjected to an annealing stress relief treatment at 400°C / 2min.

[0019] In a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, the drawing device includes a diameter reducing device, a front straightening device, a drawing die, a traction device, a rear straightening device and a slitting device;

[0020] The diameter-changing device is used to unify the diameter of the second shape memory alloy wire;

[0021] The front straightening device is used to perform a first straightening on the second shape memory alloy wire;

[0022] The drawing die is used to provide a die hole for the second shape memory alloy wire, and when the second shape memory alloy wire is subjected to a cold drawing process, the die hole is used to change the diameter of the second shape memory alloy wire;

[0023] The pulling device is used to clamp and pull one end of the second shape memory alloy wire passing through the drawing die;

[0024] The slitting device is used to cut the second shape memory alloy wire that has been subjected to multiple cold drawing processes to reach an expected diameter, so as to obtain the shape memory alloy wire that meets the expected diameter.

[0025] In the method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, the step of winding the shape memory alloy wire into a shape memory alloy spring through the spring making process includes the following steps:

[0026] Using an automatic spring winding machine, winding the shape memory alloy wire on a spring winding die to form a primary shape memory alloy spring;

[0027] The primary shape memory alloy spring and the spring winding mold are placed together in the air furnace and heated to 37° C. and kept warm to be formed into the shape memory alloy spring.

[0028] In the method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, before cooling the second elliptical cylindrical nucleus pulposus prosthesis by using liquid nitrogen and pressing the second elliptical cylindrical nucleus pulposus prosthesis into a shape memory alloy artificial nucleus pulposus prosthesis by using the stamping equipment with a set deformation amount, the method further includes:

[0029] The structural mechanical properties of the second elliptical cylindrical nucleus pulposus prosthesis were measured using a tensile testing machine.

[0030] In the method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, the diameter of the shape memory alloy wire that meets the expected diameter is defined as D, and D≤0.7 mm is satisfied.

[0031] In the method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, the spring pitch of the shape memory alloy spring is defined as h, and h satisfies 0.4 mm≤h≤0.6 mm.

[0032] In the method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, the height of the second elliptical cylindrical nucleus pulposus prosthesis is defined as H, and H satisfies 5mm≤H≤9mm.

[0033] In the method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, the short axis length of the elliptical cylindrical cavity of the second mold is 12 mm, and the long axis length of the elliptical cylindrical cavity of the second mold is 25 mm.

[0034] In the method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis described in an embodiment of the present application, the material of the shape memory alloy plate is one of titanium-nickel alloy, titanium-nickel-zirconium alloy, titanium-nickel-hafnium alloy, titanium-nickel-iron alloy, titanium-nickel-copper alloy, titanium-nickel-copper-aluminum alloy, copper-aluminum-manganese alloy, copper-aluminum-nickel alloy, copper-zinc-aluminum alloy, iron-nickel-cobalt-titanium alloy, iron-nickel-cobalt-aluminum alloy or iron-manganese-silicon alloy.

[0035] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0036] It can be seen from the above technical scheme that a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis provided in an embodiment of the present application solves the technical problem in the prior art that the artificial nucleus pulposus prosthesis is made of a high molecular polymer, by using a shape memory alloy to manufacture the artificial nucleus pulposus prosthesis, which leads to poor mechanical properties, oxidation resistance and wear resistance of the artificial nucleus pulposus prosthesis. The shape memory alloy spring is wound into a quasi-cylindrical elastomer in the cylindrical cavity of the first mold by a flat stacking winding method, and the quasi-cylindrical elastomer is made into a solid quasi-cylindrical elastomer by a stamping device and an air furnace. The solid quasi-cylindrical elastomer is made into a second elliptical cylindrical nucleus pulposus prosthesis by a stamping device, a second mold and an air furnace. The porosity of the second elliptical cylindrical nucleus pulposus prosthesis is greater than 80%, which solves the technical problem of too high elastic modulus of the artificial nucleus pulposus prosthesis in the prior art. The second elliptical cylindrical nucleus pulposus prosthesis is pressed into a smaller shape memory alloy artificial nucleus pulposus prosthesis by cooling and compressing, which solves the technical problem in the prior art that the annulus fibrosus is easily damaged during surgical implantation due to the large volume of the artificial nucleus pulposus prosthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. The drawings are not intended to be drawn to scale, and for the sake of clarity, not every component will be marked in each figure. The drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. Among them:

[0038] Figure 1 The present invention is a flowchart of a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to an embodiment of the present application.

[0039] Figure 2 This is a finished product picture of the shape memory alloy artificial nucleus pulposus prosthesis according to an embodiment of the present application.

[0040] Figure 3 Schematic diagram of the center connection lines of several spring coils of the flat spring layer according to an embodiment of the present application.

[0041] Figure 4 This is a schematic diagram of the structure of a shape memory alloy artificial nucleus pulposus prosthesis implanted into the annulus fibrosus of an intervertebral disc according to an embodiment of the present application.

[0042] Figure 5 This is a schematic diagram of the structure of the drawing equipment according to an embodiment of the present application.

[0043] Figure 6 This is a schematic structural diagram of the second mold of an embodiment of the present application.

[0044] Figure 7This is a load-displacement curve diagram of the second elliptical cylindrical nucleus pulposus prosthesis according to an embodiment of the present application.

[0045] Figure 8 Graph showing a stress-strain curve of a second elliptical cylindrical nucleus pulposus prosthesis according to an embodiment of the present application.

[0046] Description of reference numerals:

[0047] 110-Vertebral body 120-Annulus fibrosus 130-Shape memory alloy artificial nucleus pulposus prosthesis

[0048] 210-diameter reducing device 220-front straightening device 230-drawing die

[0049] 240-Post straightening device 250-Slitting device

[0050] 310- Center lines of several coils of the flat spring layer

[0051] 410- front of mold 420- rear of mold DETAILED DESCRIPTION

[0052] The embodiment of the present application provides a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis to manufacture an artificial nucleus pulposus prosthesis of a shape memory alloy, thereby solving the technical problems of artificial nucleus pulposus prosthesis in the prior art, such as large elastic modulus, poor mechanical properties, poor antioxidant ability, poor wear resistance and large size.

[0053] In view of this, the concept of the embodiment of the present application is to use shape memory alloy to make an artificial nucleus pulposus prosthesis, thereby solving the technical problem in the prior art that the artificial nucleus pulposus prosthesis is made of a high molecular polymer, resulting in poor mechanical properties, oxidation resistance and wear resistance of the artificial nucleus pulposus prosthesis. The shape memory alloy spring is wound into a quasi-cylindrical elastomer in the cylindrical cavity of the first mold by a flat stacking winding method, and the quasi-cylindrical elastomer is made into a solid quasi-cylindrical elastomer by a stamping equipment and an air furnace. The solid quasi-cylindrical elastomer is made into a second elliptical cylindrical nucleus pulposus prosthesis by a stamping equipment, a second mold and an air furnace. The porosity of the second elliptical cylindrical nucleus pulposus prosthesis is greater than 80%, which solves the technical problem of too high elastic modulus of the artificial nucleus pulposus prosthesis in the prior art. The second elliptical cylindrical nucleus pulposus prosthesis is pressed into a smaller shape memory alloy artificial nucleus pulposus prosthesis by cooling and compressing, which solves the technical problem in the prior art that the annulus fibrosus is easily damaged during surgical implantation due to the large volume of the artificial nucleus pulposus prosthesis.

[0054] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0055] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0056] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0057] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0058] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0059] The present application provides a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis. Figures 1 to 8 As shown, a method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis is used to manufacture a shape memory alloy artificial nucleus pulposus prosthesis, and the method comprises the following steps:

[0060] Step S10: Based on the metal drawing process, the shape memory alloy sheet is made into a shape memory alloy wire having a desired diameter.

[0061] In some embodiments, the process of making a shape memory alloy wire having a desired diameter from a shape memory alloy sheet material based on a metal drawing process comprises the following steps:

[0062] Step S101: placing the shape memory alloy plate in the air furnace, setting the temperature of the air furnace to 900° C., performing solution treatment for 2 hours, and performing wire cutting on the shape memory alloy plate after the solution treatment to obtain a first shape memory alloy wire with a diameter of 0.8 mm.

[0063] Among them, the material of the shape memory alloy plate is one of titanium-nickel alloy, titanium-nickel-zirconium alloy, titanium-nickel-hafnium alloy, titanium-nickel-iron alloy, titanium-nickel-copper alloy, titanium-nickel-copper-aluminum alloy, copper-aluminum-manganese alloy, copper-aluminum-nickel alloy, copper-zinc-aluminum alloy, iron-nickel-cobalt-titanium alloy, iron-nickel-cobalt-aluminum alloy or iron-manganese-silicon alloy. Preferably, the material of the shape memory alloy plate is titanium-nickel alloy, which has more stable performance. The titanium-nickel alloy includes the following components by mass percentage: titanium-44%, nickel-56%. The thickness of the shape memory alloy plate is 1.5 mm.

[0064] Step S102: immersing the first end of the first shape memory alloy wire into a corrosive solution at a uniform speed for 5-30 minutes to obtain a second shape memory alloy wire.

[0065] The corrosive liquid is used to corrode impurities on the surface of the first end of the first shape memory alloy wire and clean the surface. The corrosive liquid is a mixed solution of hydrofluoric acid, nitric acid and water. The ratio of hydrofluoric acid, nitric acid and water is 1:4:20. The length of the first end of the first shape memory alloy wire is 20 mm to 50 mm. Preferably, the immersion time is 20 minutes. The first end of the second shape memory alloy wire is the end cleaned by the corrosive liquid.

[0066] Step S103: using a drawing device to perform several cold drawing processes and a slitting process on the second shape memory alloy wire to obtain a shape memory alloy wire that meets the expected diameter, wherein in each cold drawing process of the second shape memory alloy wire, the deformation of the second shape memory alloy wire is less than 20%, and after each cold drawing process, the second shape memory alloy wire is subjected to an annealing stress relief treatment at 400°C / 2min.

[0067] Specifically, the drawing equipment includes a diameter reducing device 210, a front straightening device 220, a drawing die 230, a traction device, a rear straightening device 240 and a slitting device 250. The diameter reducing device 210, the front straightening device 220, the drawing die 230, the rear straightening device 240 and the slitting device 250 are arranged in a straight line. When in use, the first end of the second shape memory alloy wire passes through the diameter reducing device 210. The diameter reducing device 210 is used to unify the diameter of the second shape memory alloy wire. After the second shape memory alloy wire passes through the diameter reducing device 210, it enters and passes through the front straightening device 220. The front straightening device 220 is used to unify the diameter of the second shape memory alloy wire. The straightening device 220 is used to perform a first straightening on the second shape memory alloy wire. After the second shape memory alloy wire passes through the front straightening device 220, it passes through the through-die hole of the drawing die 230. The drawing die 230 is used to provide the through-die hole for the second shape memory alloy wire. When the second shape memory alloy wire is cold drawn, the through-die hole is used to change the diameter of the second shape memory alloy wire. The pulling device is used to clamp and pull the first end of the second shape memory alloy wire passing through the through-die hole of the drawing die 230 until the second shape memory alloy wire is completely straightened. The second shape memory alloy wire after drawing is passed through the drawing die 230, and the second shape memory alloy wire after drawing is passed through the rear straightening device 240. The rear straightening device 240 is used to perform a second straightening on the second shape memory alloy wire after drawing. The slitting device 250 is used to cut the second shape memory alloy wire that has reached the expected diameter after multiple cold drawing processes to obtain the shape memory alloy wire that meets the expected diameter. Each time the second shape memory alloy wire is cold drawn, it passes through the diameter reducing device 210, the front straightening device 220, the drawing die 230, the traction device and the rear straightening device 240, and the second After each cold drawing process of the second shape memory alloy wire, the second shape memory alloy wire is placed in the air furnace for annealing and stress relief treatment at 400°C / 2min to prevent the second shape memory alloy wire from generating microcracks in the next cold drawing process, which may lead to wire breakage. After the last cold drawing process is completed and the annealing and stress relief treatment at 400°C / 2min is performed to obtain the second shape memory alloy wire with the expected diameter, the slitting device 250 cuts the second shape memory alloy wire with the expected diameter to obtain a shape memory alloy wire that meets the expected diameter.

[0068] Among them, the diameter of the shape memory alloy wire that meets the expected diameter is D, and D≤0.7mm, so as to avoid the diameter of the shape memory alloy wire being too large, which will lead to too large elastic modulus of the shape memory alloy artificial nucleus pulposus prosthesis. Preferably, D can be 0.3mm, 0.5mm, or 0.7mm.

[0069] Step S20: winding the shape memory alloy wire into a shape memory alloy spring through a spring making process.

[0070] In some embodiments, the step of winding the shape memory alloy wire into a shape memory alloy spring through the spring making process comprises the following steps:

[0071] Step S201: using an automatic spring winding machine to wind the shape memory alloy wire on a spring winding die to form a primary shape memory alloy spring.

[0072] Step S202: placing the primary shape memory alloy spring and the spring winding mold together in the air furnace, heating them to 37° C. and keeping them warm to shape them into the shape memory alloy spring.

[0073] Wherein, the primary shape memory alloy spring is kept warm in the air furnace for 10-30 minutes, the spring middle diameter of the shape memory alloy spring is 5 mm, the spring pitch of the shape memory alloy spring is h, and the h satisfies 0.4 mm≤h≤0.6 mm. If the h is too small, the elastic modulus of the shape memory alloy artificial nucleus pulposus prosthesis is too large, and if the h is too large, the structure of the shape memory alloy artificial nucleus pulposus prosthesis is too loose. Preferably, the h can be 0.4 mm, 0.5 mm, or 0.6 mm. The number of coils of the shape memory alloy spring is M. This embodiment provides three preferred items of the shape memory alloy spring. When the D is 0.3 mm, the h is 0.4 mm, and the M is 100 coils. When the D is 0.5 mm, the h is 0.5 mm, and the M is 120 coils. When the D is 0.7 mm, the h is 0.6 mm, and the M is 140 coils.

[0074] Step S30: Winding a shape memory alloy spring into a cylindrical elastic body in the cylindrical cavity of the first mold by a flat-laying superposition winding method, wherein the flat-laying superposition winding method is: laying the first end of the shape memory alloy spring flat on the center of the bottom surface of the cylindrical cavity, and winding the second end of the shape memory alloy spring in a spiral shape toward the cavity wall of the cylindrical cavity with the central axis of the cylindrical cavity as the center, until the shape memory alloy spring covers the bottom surface of the cylindrical cavity to form a first layer of flat elastic body. The second end of the shape memory alloy spring is raised and wound inwardly in a spiral shape along the cavity wall of the cylindrical cavity toward the central axis of the cylindrical cavity until a second flat spring layer is formed. The above winding process is repeated until the shape memory alloy spring is wound to form an N-th flat spring layer, where N is a natural number greater than 1, and the plurality of spring coils of the upper flat spring layer are all located in the middle of the plurality of pitch spaces of the lower flat spring layer, and the N-layer flat spring layer constitutes the quasi-cylindrical elastomer.

[0075] The center line 310 of the plurality of coils of each layer of the flat spring layer is in a spiral shape, and the plane where the center line 310 is located is parallel to the bottom surface of the cylindrical cavity. The diameter of the cylindrical cavity is 20 mm. The pitch space refers to the space between any two adjacent coils in the shape memory alloy spring. In this embodiment, preferably, N can be 2 or 3. When the number of coils M of the shape memory alloy spring is 100, N is 2. The flat stacking winding method is specifically as follows: the first end of the shape memory alloy spring is flatly laid on the center of the bottom surface of the cylindrical cavity, and the second end of the shape memory alloy spring is flatly laid on the bottom surface of the cylindrical cavity. The central axis of the cylindrical cavity is taken as the center and is wound in a quasi-helical shape toward the cavity wall of the cylindrical cavity until the shape memory alloy spring covers the bottom surface of the cylindrical cavity to form a first flat spring layer, and the second end of the shape memory alloy spring is raised and wound inwardly in a quasi-helical shape along the cavity wall of the cylindrical cavity toward the central axis of the cylindrical cavity until a second flat spring layer is formed, and the plurality of spring coils of the second flat spring layer are all located in the middle of the plurality of pitch spaces of the first flat spring layer, and the first flat spring layer and the second flat spring layer constitute the quasi-cylindrical elastic body; when the spring coils of the shape memory alloy spring When the number M is 120 turns or 140 turns, N is 3, and the flat superposition winding method is specifically as follows: the first end of the shape memory alloy spring is flatly laid on the center of the bottom surface of the cylindrical cavity, and the second end of the shape memory alloy spring is wound in a spiral shape toward the cavity wall of the cylindrical cavity with the central axis of the cylindrical cavity as the center, until the shape memory alloy spring covers the bottom surface of the cylindrical cavity to form a first flat spring layer, the second end of the shape memory alloy spring is raised and wound inwardly toward the central axis of the cylindrical cavity in a spiral shape along the cavity wall of the cylindrical cavity until a second flat spring layer is formed, and the shape memory alloy spring is wound in a spiral shape toward the cavity wall of the cylindrical cavity to form a second flat spring layer. The second end of the shape memory alloy spring continues to be lifted upward, and is wound in a spiral shape toward the cavity wall of the cylindrical cavity from the central axis of the cylindrical cavity with the central axis of the cylindrical cavity as the center, until the shape memory alloy spring is wound to form a third flat spring layer, and the several spring coils of the third flat spring layer are all located in the middle of the several pitch spaces of the second flat spring layer, and the several spring coils of the second flat spring layer are all located in the middle of the several pitch spaces of the first flat spring layer, and the first flat spring layer, the second flat spring layer and the third flat spring layer constitute the quasi-cylindrical elastomer.

[0076] Step S40: Place the first mold and the cylindrical elastomer into a stamping device, press the cylindrical elastomer into a preliminary solid cylindrical elastomer, place the preliminary solid cylindrical elastomer and the first mold together in an air furnace, heat them to 37°C and keep them warm to shape them into a solid cylindrical elastomer.

[0077] Wherein, the preliminary solid cylindrical elastomer is kept warm in the air furnace for 10-30 minutes, preferably 20 minutes, and the stamping equipment is a precision press. When the D is 0.3mm, the h is 0.4mm, and the M is 100 turns, the height of the solid cylindrical elastomer is 8mm, when the D is 0.5mm, the h is 0.5mm, and the M is 120 turns, the height of the solid cylindrical elastomer is 10mm, and when the D is 0.7mm, the h is 0.6mm, and the M is 140 turns, the height of the solid cylindrical elastomer is 12mm.

[0078] Step S50: placing the solid cylindrical elastomer into the elliptical cylindrical cavity of the second mold, and using the punching equipment to press the solid cylindrical elastomer into a first elliptical cylindrical nucleus pulposus prosthesis.

[0079] Among them, the second mold includes a mold front part 410 and a mold rear part 420, and the mold front part 410 and the mold rear part 420 are detachably connected. The end of the mold front part 410 close to the mold rear part 420 and the end of the mold rear part 420 close to the mold front part 410 are both provided with semi-elliptical grooves. When the mold front part 410 and the mold rear part 420 are fitted together, the two semi-elliptical grooves form an elliptical cylindrical cavity of the second mold. The short axis length of the elliptical cylindrical cavity of the second mold is 12 mm, and the long axis length of the elliptical cylindrical cavity of the second mold is 25 mm. When in use, first separate the front part 410 of the mold and the rear part 420 of the mold, place the solid cylindrical elastomer in the middle of the front part 410 and the rear part 420 of the mold, close the front part 410 and the rear part 420 of the mold to form a first elliptical cylindrical nucleus pulposus prosthesis with an uncompressed height, put the first elliptical cylindrical nucleus pulposus prosthesis with an uncompressed height and the second mold into the stamping equipment to press it into the first elliptical cylindrical nucleus pulposus prosthesis.

[0080] Step S60: placing the first elliptical cylindrical nucleus pulposus prosthesis and the second mold together in the air furnace, heating to 37° C. and keeping the temperature to shape into a second elliptical cylindrical nucleus pulposus prosthesis, wherein the porosity of the second elliptical cylindrical nucleus pulposus prosthesis is greater than 80%.

[0081] Among them, the first elliptical cylindrical nucleus pulposus prosthesis is kept warm in the air furnace for 10-30 minutes, the height of the second elliptical cylindrical nucleus pulposus prosthesis is H, and the H satisfies 5mm≤H≤9mm. Preferably, when the height of the solid cylindrical elastomer is 8mm, the height of the second elliptical cylindrical nucleus pulposus prosthesis is 5mm, when the height of the solid cylindrical elastomer is 10mm, the height of the second elliptical cylindrical nucleus pulposus prosthesis is 7mm, and when the height of the solid cylindrical elastomer is 12mm, the height of the second elliptical cylindrical nucleus pulposus prosthesis is 9mm, to correspond to different patients with lumbar disc heights of 5mm-7mm, 7mm-9mm and above 9mm.

[0082] Step S70: using a tensile testing machine to measure the structural mechanical properties of the second elliptical cylindrical nucleus pulposus prosthesis.

[0083] Among them, in this embodiment, taking the second elliptical cylindrical nucleus pulposus prosthesis with a height of 7 mm as an example, the maximum recoverable strain of the second elliptical cylindrical nucleus pulposus prosthesis is 45%, the stiffness is 2.1N / mm~3.07N / mm, and the elastic modulus is 1.47MPa~2.16MPa. Subsequently, tests are performed when the strain amounts of the second elliptical cylindrical nucleus pulposus prosthesis are 15%, 25%, 35% and 45%, respectively. Combined with the experimental data, the following are obtained: Figure 7 The load-displacement curve of the second elliptical cylindrical nucleus pulposus prosthesis shown in FIG. Figure 8 The stress-strain curve diagram of the second elliptical cylindrical nucleus pulposus prosthesis is shown.

[0084] Step S80: using liquid nitrogen to cool the second elliptical cylindrical nucleus pulposus prosthesis, and using the stamping equipment to press the second elliptical cylindrical nucleus pulposus prosthesis into a shape memory alloy artificial nucleus pulposus prosthesis with a set deformation amount, wherein the set deformation amount is not less than 30%.

[0085] Among them, in this embodiment, it is not necessary to take the second elliptical cylindrical nucleus pulposus prosthesis out of the second mold, the second elliptical cylindrical nucleus pulposus and the second mold are directly cooled to 15°C, the second elliptical cylindrical nucleus pulposus prosthesis and the second mold are placed in a stamping device, and the deformation amount of the second elliptical cylindrical nucleus pulposus prosthesis is set to 30%, the stamping device is started, the second elliptical cylindrical nucleus pulposus prosthesis is pressed into a shape memory alloy artificial nucleus pulposus prosthesis, and the shape memory alloy artificial nucleus pulposus prosthesis is stored in an environment below 37°C. Based on the one-way memory effect of the shape memory alloy, the second elliptical cylindrical nucleus pulposus is pressed into a smaller shape memory alloy artificial nucleus pulposus prosthesis by cooling and compressing. Reducing the volume of the artificial nucleus pulposus prosthesis is beneficial to not destroying the annulus fibrosus during surgical implantation. When the shape memory alloy artificial nucleus pulposus prosthesis is implanted into the human body, the temperature of the shape memory alloy artificial nucleus pulposus prosthesis gradually reaches the human body temperature of 37°C, the shape memory alloy artificial nucleus pulposus prosthesis is transformed from martensite to austenite parent phase, and the shape of the shape memory alloy artificial nucleus pulposus prosthesis is restored to the shape of the second elliptical cylindrical nucleus pulposus prosthesis, meeting the patient's use requirements.

[0086] In summary, the manufacturing method of a shape memory alloy artificial nucleus pulposus prosthesis provided in the embodiment of the present application solves the technical problem in the prior art that the artificial nucleus pulposus prosthesis is made of a high molecular polymer due to the poor mechanical properties, oxidation resistance and wear resistance of the artificial nucleus pulposus prosthesis caused by the material of the artificial nucleus pulposus prosthesis being a high molecular polymer. The shape memory alloy spring is wound into a quasi-cylindrical elastomer in the cylindrical cavity of the first mold by a flat stacking winding method, and the quasi-cylindrical elastomer is made into a solid quasi-cylindrical elastomer by a stamping device and an air furnace. The solid quasi-cylindrical elastomer is made into a second elliptical cylindrical nucleus pulposus prosthesis by a stamping device, a second mold and an air furnace. The porosity of the second elliptical cylindrical nucleus pulposus prosthesis is greater than 80%, which solves the technical problem in the prior art that the elastic modulus of the artificial nucleus pulposus prosthesis is too high. The second elliptical cylindrical nucleus pulposus prosthesis is pressed into a smaller shape memory alloy artificial nucleus pulposus prosthesis by cooling and compressing, which solves the technical problem in the prior art that the annulus fibrosus is easily damaged during surgical implantation due to the large volume of the artificial nucleus pulposus prosthesis.

[0087] The above is a detailed introduction to the method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis, which is used to manufacture a shape memory alloy artificial nucleus pulposus prosthesis, characterized in that: The method comprises the following steps: Based on the metal drawing process, the shape memory alloy sheet is made into a shape memory alloy wire with a desired diameter; Through a spring making process, the shape memory alloy wire is wound into a shape memory alloy spring; A shape memory alloy spring is wound into a quasi-cylindrical elastic body in a cylindrical cavity of a first mold by a flat-laying and superimposed winding method, wherein the flat-laying and superimposed winding method is as follows: the first end of the shape memory alloy spring is flat-laid on the center of the bottom surface of the cylindrical cavity, the second end of the shape memory alloy spring is wound in a quasi-helical shape toward the cavity wall of the cylindrical cavity with the central axis of the cylindrical cavity as the center, until the shape memory alloy spring covers the bottom surface of the cylindrical cavity to form a first flat-laid spring layer, the second end of the shape memory alloy spring is raised and wound inwardly toward the central axis of the cylindrical cavity in a quasi-helical shape along the cavity wall of the cylindrical cavity until a second flat-laid spring layer is formed, and the above-mentioned winding process is repeated until the shape memory alloy spring is wound to form an Nth flat-laid spring layer, wherein N is a natural number greater than 1, and the plurality of coils of the upper flat-laid spring layer are all located in the middle of the plurality of pitch spaces of the lower flat-laid spring layer, and the N layers of the flat-laid spring layers together constitute the quasi-cylindrical elastic body; Putting the first mold and the quasi-cylindrical elastic body into a stamping device, pressing the quasi-cylindrical elastic body into a preliminary solid quasi-cylindrical elastic body, and putting the preliminary solid quasi-cylindrical elastic body and the first mold into an air furnace together, heating them to 37° C. and keeping them warm to shape them into a solid quasi-cylindrical elastic body; Putting the solid cylindrical elastic body into the elliptical cylindrical cavity of the second mold, and using the punching equipment to press the solid cylindrical elastic body into a first elliptical cylindrical nucleus pulposus prosthesis; Putting the first elliptical cylindrical nucleus pulposus prosthesis and the second mold together into the air furnace, heating to 37° C. and keeping the temperature to shape into a second elliptical cylindrical nucleus pulposus prosthesis, wherein the porosity of the second elliptical cylindrical nucleus pulposus prosthesis is greater than 80%; The second elliptical cylindrical nucleus pulposus prosthesis is cooled by liquid nitrogen, and the second elliptical cylindrical nucleus pulposus prosthesis is pressed into a shape memory alloy artificial nucleus pulposus prosthesis with a set deformation amount by the punching equipment, and the set deformation amount is not less than 30%.

2. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 1, characterized in that: The method of manufacturing a shape memory alloy sheet into a shape memory alloy wire having an expected diameter based on a metal drawing process comprises the following steps: Placing the shape memory alloy plate in the air furnace, setting the temperature of the air furnace to 900° C., performing solution treatment for 2 hours, and performing wire cutting on the shape memory alloy plate after the solution treatment to obtain a first shape memory alloy wire with a diameter of 0.8 mm; The first end of the first shape memory alloy wire is immersed in a corrosion solution at a uniform speed for 5-30 minutes to obtain a second shape memory alloy wire, wherein the corrosion solution is a mixed solution of hydrofluoric acid, nitric acid and water, and the ratio of the hydrofluoric acid, nitric acid and water is 1:4:20; The second shape memory alloy wire is subjected to several cold drawing processes and slitting processes by using a drawing device to obtain a shape memory alloy wire having an expected diameter, wherein in each cold drawing process of the second shape memory alloy wire, the deformation amount of the second shape memory alloy wire is less than 20%, and after each cold drawing process, the second shape memory alloy wire is subjected to an annealing stress relief treatment at 400°C / 2min.

3. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 2, characterized in that: The drawing equipment includes a diameter reducing device, a front straightening device, a drawing die, a pulling device, a rear straightening device and a slitting device; The diameter-changing device is used to unify the diameter of the second shape memory alloy wire; The front straightening device is used to perform a first straightening on the second shape memory alloy wire; The drawing die is used to provide a die hole for the second shape memory alloy wire, and when the second shape memory alloy wire is subjected to a cold drawing process, the die hole is used to change the diameter of the second shape memory alloy wire; The pulling device is used to clamp and pull one end of the second shape memory alloy wire passing through the drawing die; The slitting device is used to cut the second shape memory alloy wire that has been subjected to multiple cold drawing processes to reach an expected diameter, so as to obtain the shape memory alloy wire that meets the expected diameter.

4. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 1, characterized in that: The step of winding the shape memory alloy wire into a shape memory alloy spring through the spring making process comprises the following steps: Using an automatic spring winding machine, winding the shape memory alloy wire on a spring winding die to form a primary shape memory alloy spring; The primary shape memory alloy spring and the spring winding mold are placed together in the air furnace and heated to 37° C. and kept warm to be formed into the shape memory alloy spring.

5. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 1, characterized in that: Before cooling the second elliptical cylindrical nucleus pulposus prosthesis by using liquid nitrogen and pressing the second elliptical cylindrical nucleus pulposus prosthesis into a shape memory alloy artificial nucleus pulposus prosthesis with a set deformation amount by using the stamping equipment, the method further includes: The structural mechanical properties of the second elliptical cylindrical nucleus pulposus prosthesis were measured using a tensile testing machine.

6. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 1, characterized in that: The diameter of the shape memory alloy wire that meets the expected diameter is defined as D, and D≤0.7 mm is satisfied.

7. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 1, characterized in that: The spring pitch of the shape memory alloy spring is defined as h, and h satisfies 0.4 mm ≤ h ≤ 0.6 mm.

8. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 1, characterized in that: The height of the second elliptical cylindrical nucleus pulposus prosthesis is defined as H, and H satisfies 5mm≤H≤9mm.

9. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 1, characterized in that: The minor axis length of the elliptical cylindrical cavity of the second mold is 12 mm, and the major axis length of the elliptical cylindrical cavity of the second mold is 25 mm.

10. The method for manufacturing a shape memory alloy artificial nucleus pulposus prosthesis according to claim 1, characterized in that: The material of the shape memory alloy plate is one of titanium-nickel alloy, titanium-nickel-zirconium alloy, titanium-nickel-hafnium alloy, titanium-nickel-iron alloy, titanium-nickel-copper alloy, titanium-nickel-copper-aluminum alloy, copper-aluminum-manganese alloy, copper-aluminum-nickel alloy, copper-zinc-aluminum alloy, iron-nickel-cobalt-titanium alloy, iron-nickel-cobalt-aluminum alloy or iron-manganese-silicon alloy.

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