CN112535560B - Super-soft smooth nickel-titanium alloy intracranial intravascular stent with micro-nano structure - Google Patents

Abstract

Translated fromChinese

本发明涉及一种具有微纳结构的超柔顺镍钛合金颅内血管支架，可用于辅助弹簧圈栓塞治疗颅内动脉瘤，属于医疗器械领域。颅内血管支架主体由开环结构与闭环结构组成，开环结构由沿周向排布的第一V字形单元与沿周向排布的第二V字形单元通过连接杆连接形成，闭环结构由沿周向排布的第二V字形单元通过连接杆连接形成，第二V字形单元开环自由端与第一V字形单元开环自由端的数量比为1：2；开环结构增强支架柔顺性和贴壁性，闭环结构提供支撑性能。本发明颅内血管支架具有超柔顺性能，能适用于辅助弹簧圈栓塞治疗颅内复杂血管处的动脉瘤(如：大曲率血管、变径血管)，达到良好的贴壁效果。The invention relates to a super-compliant nickel-titanium alloy intracranial vascular stent with a micro-nano structure, which can be used for assisting coil embolization in the treatment of intracranial aneurysms, and belongs to the field of medical devices. The main body of the intracranial vascular stent is composed of an open-loop structure and a closed-loop structure. The open-loop structure is formed by connecting a first V-shaped unit arranged in the circumferential direction and a second V-shaped unit arranged in the circumferential direction through a connecting rod. The closed-loop structure is formed by The second V-shaped units arranged in the circumferential direction are connected by connecting rods, and the number ratio of the open-loop free ends of the second V-shaped unit to the open-loop free ends of the first V-shaped unit is 1:2; the open-loop structure enhances the flexibility of the stent and adherence, the closed-loop structure provides supportive performance. The intracranial vascular stent of the present invention has super-compliant performance, can be used for assisting coil embolization in the treatment of aneurysms at complex intracranial blood vessels (eg, large-curvature blood vessels, variable-diameter blood vessels), and achieves a good wall-adhering effect.

Description

Super-soft smooth nickel-titanium alloy intracranial intravascular stent with micro-nano structure

Technical Field

The invention relates to a super-soft and smooth nickel-titanium alloy intracranial vascular stent with a micro-nano structure, which can be used for assisting a spring ring to embolize to treat intracranial aneurysm and belongs to the field of medical instruments.

Background

Intracranial aneurysm is abnormal expansion of intracranial arterial vessel wall caused by congenital abnormal defect of blood vessel or acquired lesion wound, and is the leading cause of subarachnoid hemorrhage. Compared with the operations of clamping, ligating and the like of the aneurysm, the endovascular interventional therapy is safer and has wider adaptability, is a main intracranial aneurysm treatment means at present, and can achieve aneurysm occlusion by an intracranial vascular stent to assist spring ring embolism.

However, intracranial vessels are complicated to detour, and intracranial aneurysms occur well at the bifurcation of the basilar artery ring and its main branches, often with varying degrees of curvature, and the diameters of the vessels may not be uniform. In addition, intracranial aneurysms have very large size differences, and the current interventional treatment of some wide-neck and fusiform aneurysms is still difficult. Aiming at the existing products, the intracranial stent structure is roughly divided into an open-loop structure and a closed-loop structure, each structural stent has respective advantages and disadvantages, for a blood vessel with higher curvature, the bending performance of the open-loop structural stent is better than that of the closed-loop structural stent, and the phenomena of folding, ovalization and the like can be avoided; in addition, for the open-loop structure stent with long unit span, the open-loop part of the open-loop structure stent can cause the non-adherence phenomenon or extend into aneurysm to cause the problems of thrombus and the like. Although the closed-loop structure stent can provide higher support performance, the whole stent is continuous and has higher rigidity, so the whole stent is hard, has poor adherence after implantation, even shifts, and finally causes complications such as thrombus, restenosis and the like.

Most of the existing products are of uniform structural design, and for intracranial complex blood vessels, especially for the conditions of large curvature and inconsistent change of blood vessel diameter, flexibility/adherence and supporting performance are rarely coordinated, local support is difficult to be provided for wide neck and fusiform aneurysm neck parts needing excessive embolism spring coils, and the problems of open-loop structural supporting performance, gaps, non-adherence and the like are not solved. In addition, it is reported that the micro-nano structure on the surface of the substrate is beneficial to the adhesion of protein, cells and the like, and if the micro-nano structure is introduced on the surface of the intracranial vascular stent, the micro-nano structure can play a beneficial role in reconstructing blood vessels after the stent is implanted.

Disclosure of Invention

The invention aims to provide a super-soft cis-nickel-titanium alloy intracranial intravascular stent with a micro-nano structure, which is used for assisting a spring ring to embolize and treat intracranial aneurysm. The intracranial vascular stent comprises an open-loop structure and a closed-loop structure, and the flexibility/adherence of the stent is enhanced and the support performance is provided respectively; meanwhile, the supporting performance is enhanced by adding a closed loop structure unit in the middle part of the stent (such as a tumor neck opening), and the possibility of non-adherence of an open loop extending into a tumor and a blood vessel wall is reduced. In addition, a micro-nano structure is introduced on the surface of the intracranial vascular stent, so that the endothelialization of blood vessels after the stent is implanted is promoted.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the utility model provides an encephalic vascular support of super gentle cis-nickel titanium alloy with micro-nano structure, encephalic vascular support main part comprises open loop structure and closed loop structure, and the open loop structure is connected through first connecting rod by the first V font unit of arranging along circumference and the second V font unit of arranging along circumference and is formed, and closed loop structure is connected through the second connecting rod by the second V font unit of arranging along circumference and is formed, and the quantity ratio of second V font unit open loop free end and first V font unit open loop free end is 1: 2; the open loop structure enhances the flexibility and adherence of the stent, and the closed loop structure provides the support performance.

The super-soft cis-nickel-titanium alloy intracranial vascular stent with the micro-nano structure has the advantages that the surface of the intracranial vascular stent is provided with the porous micro-nano structure, and the pore diameter of the micro-nano structure reaches 50-300 nm.

The super-soft cis-nickel-titanium alloy intracranial intravascular stent with the micro-nano structure is prepared by the following steps: soaking the intracranial vascular stent in an acid solution system, and applying voltage at room temperature to perform dealloying treatment for 30-120 min; wherein the acid solution system is nitric acid, the concentration is 1-3 mol/L, and the voltage is 1.5-4.5V.

The open-loop structure of the intracranial vascular stent is formed by connecting a first V-shaped unit which is circumferentially arranged for 12 periods with a second V-shaped unit which is circumferentially arranged for 8 periods through a first connecting rod; the closed loop structure is formed by connecting second V-shaped units which are circumferentially arranged for 8 periods through a second connecting rod; the ratio of the length dimension to the width dimension of the first V-shaped unit is 0.84, and the filament width is 0.03-0.05 mm; the ratio of the length dimension to the width dimension of the second V-shaped unit is 0.6-0.7, and the filament width is 0.05-0.07 mm; the height a of the second connecting rod is 0.05 +/-0.01 mm, and the width b of the second connecting rod is 0.05 +/-0.01 mm; the height c of the first connecting rod is 0.06 +/-0.01 mm, and the width d of the first connecting rod is 0.0857 +/-0.01 mm.

The radius of a fillet at the free end of the open ring is 0.05-0.07 mm, and the radius of a transition fillet is 0.02 +/-0.01 mm.

The open-loop structure and the closed-loop structure of the intracranial vascular stent are uniformly distributed, namely, open-loop structural units are uniformly added on the surface of the intracranial vascular stent, and the open-loop structural units account for 20-40% of the surface area of the whole intracranial vascular stent.

In order to assist the spring ring embolism to treat intracranial aneurysm and improve the stability of the support, the middle part and two ends of the intracranial vascular support are provided with closed-loop structural units, and the size of the closed-loop structure in the middle part is 2.2-6.6 mm along the length direction of the support.

The length of the intracranial vascular stent is 15-40 mm, the nominal diameter of the intracranial vascular stent is 2.5-4.5 mm, and the wall thickness is 0.05-0.085 mm; the vertex of the two ends of the intracranial vascular stent is provided with a developing rod, the length of the developing rod is 0.5-1.0 mm, and the width of the developing rod is 0.15 +/-0.05 mm.

The intracranial vascular stent is characterized in that the basement of the intracranial vascular stent is made of super-elastic nickel-titanium alloy material, and the elastic range of the intracranial vascular stent is 10-15%; the intracranial intravascular stent developing rod is made of platinum-iridium alloy.

The design idea of the invention is as follows:

based on the advantages of the open-loop structure support and the closed-loop structure support, the number of the periodic units is adjusted to form an open-loop structure unit and a closed-loop structure unit in a combined mode, and the proportion of the open-loop structure on the surface of the support and the position of the closed-loop structure on the surface of the support are further adjusted; finally, a micro-nano structure is introduced into the surface, and the ultra-soft smooth nickel-titanium alloy intracranial vascular stent with the micro-nano structure is designed, has sufficient supporting strength, good flexibility and adherence, reduces the extension of the free end of the open loop, and realizes the mechanical enhancement of a specific position; the promotion of vascular endothelialization after stent implantation is achieved in terms of biological properties. Closed loop structural units are additionally arranged at the middle part and the two ends of the intracranial intravascular stent, so that sufficient supporting strength is provided, the stability of the stent can be improved, higher supporting force can be provided at the middle part of the stent, and the spring ring is resisted at the neck opening of the wide neck, fusiform aneurysm and other complex pathological conditions, so that the stent is prevented from being crushed or collapsed. The open-loop structure has the advantages that due to the fact that part of connection points of the open-loop structure are disconnected, the flexibility of the stent can be improved, the phenomena of folding, ovalization and the like are avoided, and meanwhile the open-loop structure has better adaptability to blood vessels with uneven diameters; in addition, the open loop structure with a small length-width ratio has small unit span, the open loop part forms structures with different circumferential periods, and the free ends are staggered and not contacted, so that the possibility that the free ends of the open loop are not attached to the wall or extend into the aneurysm can be reduced. And finally, introducing a micro-nano structure on the surface of the intracranial vascular stent through dealloying treatment to promote vascular endothelialization after the stent is implanted.

Due to the adoption of the technical scheme, the invention has the following advantages and beneficial effects:

1. the design method of the mixed unit of the open-loop structure and the closed-loop structure can adjust the positions and the number of the open-loop structure and the closed-loop structure according to the bending use conditions of different blood vessels, and realize different mechanical properties of the intracranial intravascular stent.

2. According to the stent, on the basis of a closed-loop structure, an open-loop structure with a small length-width ratio and staggered free ends is added, so that the flexibility and the adherence of the stent are improved, the phenomena of folding, ovalization and the like of the stent are reduced, and the possibility of non-adherence of the free ends of the open-loop structure is reduced.

3. According to the invention, the closed-loop structure is added in the middle of the stent, so that good mechanical support can be provided at the neck of a large or wide-neck aneurysm and other complicated aneurysm lesions, the situation that more spring rings need to be implanted is effectively prevented, and the stent is prevented from collapsing; in addition, the likelihood of the open loop structure extending into the aneurysm may be reduced.

4. The surface of the stent is introduced into a micro-nano structure through dealloying treatment, so that the endothelialization of the blood vessel after the stent is implanted is promoted.

Drawings

Fig. 1(a) is a schematic structural view of an intracranial vascular stent unit, fig. 1(b) is a detailed enlarged view of a connecting rod part of a second V-shaped unit 2, and fig. 1(c) is a detailed enlarged view of connecting rod parts of a first V-shaped unit 1 and the second V-shaped unit 2. In the figure, 1 is a first V-shaped unit, 2 is a second V-shaped unit, 3 is a first connecting rod, 4 is a second connecting rod, a is the height of the second connecting rod, b is the width of the second connecting rod, c is the height of the first connecting rod, and d is the width of the first connecting rod.

Fig. 2 is a planar expansion schematic diagram of an intracranial vascular stent designed with a middle closed loop structure length l of 6.6 mm.

Figure 3 is a plan deployment cut view of the intracranial vascular stent designed in example 1.

Fig. 4 is a drawing of a processing object of the intracranial vascular stent designed in example 1.

FIG. 5 is a graph showing the results of the three-point bending test. Wherein, (a) is the bending degree of the bracket in the test process, and (b) is a load-deflection curve of the bracket.

FIG. 6 is a graph of radial support performance test results. Wherein, (a) is a curve of radial supporting force changing with diameter measured by a radial pressing and holding method, and (b) is a curve of flat supporting force changing with deformation measured by a flat plate method.

FIG. 7 is a graph showing a distribution of reaction force in the displacement direction of the indenter (unit: N) as a result of the simulation of the holder in example 4. Wherein, (a) is without middle part reinforcing, (b) middle part 2.25mm length support, (c) middle part 4.75mm length support.

FIG. 8 is a graph of the support force at the middle of the bracket as a function of the displacement of the ram.

Fig. 9 is an enlarged view of the adherent state of a stent after implantation of a simulated stent. Wherein, (a) is the result of pure closed-loop stent implantation, and (b) is the result of stent model implantation in example 1.

FIG. 10 is a process chart for releasing the stent processed in example 1 into a bent silicone hose model having a centerline radius of 4mm and an inner diameter of 3 mm. Wherein, (a) is a stent release 1/4 diagram, (b) is a stent release 1/2 diagram, (c) is astent release 3/4 diagram, and (d) is a stent release profile.

FIG. 11 is a process chart for releasing the stent processed in example 1 into a bent silicone hose model having a centerline radius of 5mm and an inner diameter of 3 mm. Wherein, (a) is a map of stent release initiation, (b) is a map of stent release 1/4, (c) is a map of stent release 1/2, and (d) is a map of stent release overall.

FIG. 12 is a process chart for releasing the stent processed in example 1 into a bent silicone hose model having a centerline radius of 6mm and an inner diameter of 3 mm. Wherein, (a) is a map of stent release initiation, (b) is a map of stent release 1/4, (c) is a map of stent release 1/2, and (d) is a map of stent release overall.

FIG. 13 is a graph of the release of the stent processed in example 1 into an in vitro silica gel aneurysm vessel model with an inner diameter of 3 mm. Wherein, (a) is a map of the beginning of the release of the stent, and (b) is a map of the total release of the stent.

FIG. 14 is a Scanning Electron Microscope (SEM) image of a nickel titanium alloy cylinder after a surface dealloying process. Wherein, (a) is a micro-nano structure SEM image, and (b) is a micro-nano structure magnified SEM image.

Detailed Description

As shown in fig. 1(a), (b), and (c), the first V-shaped units 1 arranged in 12 periods along the circumferential direction and the second V-shapedunits 2 arranged in 8 periods along the circumferential direction are connected by 4 first connectingrods 3 to form an open loop structure, and the number ratio of the open loop free ends is 1: 2(8 cycles: 12 cycles), the flexibility and adherence of the stent are enhanced, the radius of a fillet at the free end of the open ring is 0.05-0.07 mm, so that the situation that the free end of the intracranial vascular stent is too sharp after being implanted to stab a blood vessel is prevented; the second V-shapedunits 2 which are circumferentially arranged for 8 periods are connected through 8 second connecting rods 4 to form a closed-loop structure, and support performance is mainly provided. Wherein, the ratio of the length dimension to the width dimension of the first V-shaped unit 1 is 0.84, and the filament width is preferably 0.03-0.05 mm; the ratio of the length dimension to the width dimension of the second V-shapedunit 2 is 0.6-0.7, and the filament width is preferably 0.05-0.07 mm. The height a of the second connecting rod is 0.05 +/-0.01 mm, the width b of the second connecting rod is 0.05 +/-0.01 mm, the height c of the first connecting rod is 0.06 +/-0.01 mm, and the width d of the first connecting rod is 0.0857 +/-0.01 mm. In order to avoid stress concentration in the process of pressing and holding the stent and fatigue damage caused by pulsation of blood vessels after implantation, the radius of the transition fillet is 0.02 +/-0.01 mm, so that the long-term service life of the stent is prolonged.

As shown in figure 2, in order to match the neck of an intracranial aneurysm, the middle part of the intracranial vascular stent is locally reinforced by adopting a closed loop structure, and the size of the closed loop structure in the middle part is preferably 2.2 mm-6.6 mm along the length direction l of the stent. In order to improve the stability of the intracranial vascular stent, closed loop structures are added at two ends of the stent at the same time. The open-loop structure and the closed-loop structure of the intracranial vascular stent adopt an evenly distributed mode, and the unit span and the position of the closed-loop structure and the open-loop structure are adjusted, so that different open-loop structures can be obtained, and the open-loop structures account for 20% -40% of the surface area of the whole intracranial vascular stent.

According to a stent plane unfolding cutting drawing, the nickel-titanium alloy intracranial vascular stent is processed and prepared by the steps of carrying out laser cutting, cleaning, mold expansion, heat treatment stress removal and shaping, electrolytic polishing, cleaning again and the like on a nickel-titanium alloy tube, wherein the length of the intracranial vascular stent is preferably 15-40 mm, the nominal diameter of the intracranial vascular stent is preferably 2.5-4.5 mm, and the wall thickness is preferably 0.05-0.085 mm; the vertex of the two ends of the intracranial vascular stent is provided with a developing rod, the length of the developing rod is 0.5-1.0 mm, and the width of the developing rod is 0.15 +/-0.05 mm.

The terms of relevance in the present invention are explained as follows:

the height dimensions of the first and second V-shapedcells 1 and 2 are: the length of the middle point of the two connecting rods of the single periodic V-shaped unit mesh along the circumferential direction of the bracket on the plane drawing of the bracket; the length dimensions of the first V-shaped unit 1 and the second V-shapedunit 2 are as follows: the length of the middle points of the two connecting rods of the single periodic V-shaped unit mesh wire along the axial direction of the bracket on the plane drawing of the bracket. The intracranial vascular stent filament width refers to: the minimum value of the length of a connecting line of any two points on the edges of the adjacent open-loop or closed-loop structures.

The technical solution of the present invention is further explained below with reference to the embodiments and the accompanying drawings.

Example 1

The embodiment designs a super-soft nickel-titanium alloy intracranial intravascular stent with a micro-nano structure, wherein the middle part of the design is locally reinforced by adopting a closed-loop structure, and the length of the stent is 2.25 mm; the open-loop structure accounts for 30% of the surface area of the whole intracranial vascular stent; the width of the second V-shapedunit 2 is 0.05mm, the width of the first V-shaped unit 1 is 0.0367mm, the height a of the connecting rod (b) is 0.05mm, the width b is 0.05mm, the height c of the connecting rod (c) is 0.06mm, and the width d is 0.0857 mm. The ratio of the length dimension to the width dimension of the first V-shaped unit 1 is 0.84, and the ratio of the height dimension to the width dimension of the second V-shapedunit 2 is 0.6-0.7.

As shown in fig. 3, the planar expansion cutting diagram of the intracranial vascular stent. And carrying out laser cutting, cleaning, mold expansion, heat treatment stress removal and shaping, electrolytic polishing, cleaning again and the like on the nickel-titanium alloy tube with the outer diameter of 2.8mm according to a design drawing to prepare the final intracranial vascular stent. As shown in FIG. 4, the intracranial vascular stent has a nominal diameter of 4.5mm, a length of 25mm, a shaft length of 0.7mm, a shaft width of 0.15mm, and a wall thickness of 0.05 mm.

Example 2

This example performed three-point bending test tests on the stent processed in example 1 to characterize the flexibility of the stent. The three-point bending experimental equipment consists of two lower fixed supporting parts (4mm diameter parallel cylinders) and an upper loading part (4mm diameter cylinder). A fixed span three-point bending method is adopted, and the span of the lower fixed supporting part is set to be 20 mm. The method comprises the following steps:

a) assembling and lofting: the sample is placed perpendicular to the fixed support members and the loading member is assembled parallel to the fixed support members and centered between the two fixed support members.

b) Starting a test: the load was applied at a constant rate of 0.05mm/s until a predetermined maximum deflection of 4.5 mm.

c) It was recorded whether the sample exhibited sufficiently uniform bending throughout the test and a curve of load versus deflection was plotted.

Fig. 5 shows the results of the three-point bending test. As shown in fig. 5(a), the stent was bent during the process, and the stent was bent sufficiently and uniformly during the entire test process, and was not folded or ovalized. As shown in fig. 5(b), the stent load-deflection curve, calculated to be 2.75mm, gave a bending moment of 0.149N mm for the stent of example 1, which was lower than the Enterprise (0.772N mm) closed loop stent, the Solitaire (0.428N mm) closed loop stent, and better than the Neuroform (0.235N mm) open loop stent.

Example 3

This example measured the relationship between the radial support force and the stent diameter of the stent fabricated in example 1 during release and compression to characterize the stent's support properties. Respectively adopting a radial pressing and holding method and a flat plate method:

1. radial press-holding method:

a) placing the holder into a device, the initial aperture of the device being set to 7 mm;

b) reducing the stent diameter to 0.5mm at a rate of 0.0156 mm/s;

c) the aperture then increased at a rate of 0.0156mm/s and the stent was slowly unloaded to 4.5 mm;

d) during stent crimping, the relationship between radial force and stent diameter was recorded.

2. Plate method:

a) placing the support between the two flat plates, positioning the support at the center of the component, and adjusting the pressure head to be just attached to the surface of the support;

b) applying load at a constant rate of 0.05mm/s until the displacement reaches 50% of the stent diameter (i.e. 2.25mm), and returning at the same speed;

c) load-displacement curves were recorded.

Fig. 6 shows the results of the radial support performance test of the stent. As shown in fig. 6(a), the radial holding method is adopted to test the curve of the radial supporting force along with the diameter change, and the radial supporting force of the stent in the embodiment 1 is 1.58N and 0.929N at the positions of 3.0mm and 4.0mm of the target blood vessel diameter respectively; as shown in FIG. 6(b), when the deformation reaches 50% of the scaffold diameter (i.e. 2.25mm), the open-loop scaffold force value reaches 0.01605N/mm, which is higher than Neuroflorm (0.0065N/mm) open-loop scaffold, Enterprise (0.0082N/mm) closed-loop scaffold and Solitaire (0.0106N/mm) closed-loop scaffold, and has enough radial support force.

Example 4

In the embodiment, the supports without middle reinforcement, middle 2.25mm length and middle 4.75mm length are respectively designed, and the reaction force of the pressure head on the supports is extracted by simulating the process of compressing the supports by the hemispherical pressure head so as to explore the effect of the middle closed loop structure local reinforcement of the intracranial vascular support.

And simulating a 5mm hemispherical pressure head, pressing downwards by the same displacement of 0.7125mm, and extracting the magnitude of the reaction force value of the support on the hemispherical rigid body reference point. As shown in FIG. 7, the bracket simulation results show that the reaction force distribution along the displacement direction of the pressure head (without middle reinforcement (a), middle 2.25mm length (b) and middle 4.75mm length (c)) is 0.0162N (a) < 0.0225N (b) < 0.0337N (c) respectively, and the middle force value of the bracket is larger along with the increase of the middle length, so that the supporting and reinforcing effect is better.

Further, the change curve of the middle support force with the displacement of the indenter was actually measured for the holder processed in example 1 using a 4mm indenter. The method comprises the following steps:

a) assembling and lofting: placing a sample on a flat plate perpendicular to an upper loading part (a cylinder with the diameter of 4mm), positioning the loading part at the center of a support, and adjusting a pressure head to be just attached to the surface of the support;

it is assembled parallel to the fixed support members and centered between the two fixed support members.

b) Applying load at a constant rate of 0.05mm/s until the displacement reaches 50% of the stent diameter (i.e. 2.25mm), and returning at the same speed;

c) load-displacement curves were recorded.

As shown in fig. 8, the support force at the center of the bracket varies with the displacement of the ram. When the displacement reaches 0.7125mm, the support supporting force is 0.0225N, which corresponds well to the simulation result.

Example 5

In the design of the embodiment, the stent structure model and the pure closed-loop structure model with the unit length-width ratio of 1.2-1.9 in the embodiment 1 are adopted to simulate and implant the model into blood vessels with different diameters, and the influence of the open-loop structure and the closed-loop structure on the adherence is researched. The stent is pressed to 1.8mm and delivered into a blood vessel to be released, so that the stent is expanded in a transition region of the blood vessel, a simulated stent model is implanted into the blood vessel with different diameters (the inner diameter of one end is 3.5mm, and the inner diameter of one end is 2mm), and the adherence degree of the simulated stent model is observed. As can be seen from fig. 9, the adherence of the stent model (b) to vessels of varying diameter in example 1 is superior to that of the pure closed-loop stent (a).

Example 6

In this embodiment, the stents processed in example 1 are released into the curved silicone hose models with a centerline radius of 4mm, 5mm, 6mm and an inner diameter of 3mm, and the releasing processes are shown in fig. 10 (centerline radius of 4mm), fig. 11 (centerline radius of 5mm) and fig. 12 (centerline radius of 6mm), respectively. In the three-time release process of different central line radiuses, the support can achieve good wall adhesion, the folding phenomenon is not generated, and excellent flexibility is achieved.

The stent processed in example 1 was then released into an in vitro silica gel aneurysm vascular model with an inner diameter of 3mm, as shown in fig. 13. For the curved vessel containing aneurysm, the stent can not only realize good adherence, but also the open loop free end does not appear to stretch into the aneurysm at the neck opening part of the aneurysm.

Example 7

The nickel-titanium alloy material which is the same as that of the processed bracket is cut into

The column is polished by 150#, 800#, 2000# sandpaper and SiO₂Polishing by using the polishing solution, and performing dealloying treatment to form a micro-nano structure surface.

Soaking intracranial vascular stent in 2mol/L HNO₃In the aqueous solution, 3V voltage is firstly applied at room temperature, dealloying treatment is carried out for 3min, then treatment is carried out for 30min at 1.9V voltage, the micro-nano surface shown in the figure 14 is obtained, and the micro-nano aperture reaches 50-300 nm.

The embodiment result shows that the intracranial vascular stent has super-soft performance, can be suitable for assisting the spring ring embolism to treat aneurysms (such as large-curvature blood vessels and variable-diameter blood vessels) at intracranial complex blood vessels, and achieves a good wall-adhering effect.

Claims (8)

Translated fromChinese

1.一种具有微纳结构的超柔顺镍钛合金颅内血管支架，其特征在于，颅内血管支架主体由开环结构与闭环结构组成，开环结构由沿周向排布12个周期的第一V字形单元与沿周向排布8个周期的第二V字形单元通过第一连接杆连接形成，闭环结构由沿周向排布的第二V字形单元通过第二连接杆连接形成，第二V字形单元开环自由端与第一V字形单元开环自由端的数量比为1：2；开环结构增强支架柔顺性和贴壁性，闭环结构提供支撑性能；1. a super-compliant nickel-titanium alloy intracranial vascular stent with micro-nano structure is characterized in that, the intracranial vascular stent main body is made up of an open-loop structure and a closed-loop structure, and the open-loop structure is composed of 12 cycles arranged along the circumferential direction. The first V-shaped unit and the second V-shaped unit arranged in the circumferential direction for 8 periods are connected by a first connecting rod, and the closed-loop structure is formed by connecting the second V-shaped units arranged in the circumferential direction through a second connecting rod, The number ratio of the open-loop free ends of the second V-shaped unit to the open-loop free ends of the first V-shaped unit is 1:2; the open-loop structure enhances the flexibility and adherence of the stent, and the closed-loop structure provides support performance;为了辅助弹簧圈栓塞治疗颅内动脉瘤并提高支架稳定性，颅内血管支架中部与两端增加闭环结构单元设计，中部闭环结构尺寸沿支架长度方向为2.2mm～6.6mm。In order to assist the coil embolization in the treatment of intracranial aneurysms and improve the stability of the stent, a closed-loop structural unit design was added in the middle and both ends of the intracranial vascular stent.2.按照权利要求1所述的具有微纳结构的超柔顺镍钛合金颅内血管支架，其特征在于，颅内血管支架表面具有多孔微纳结构，微纳结构孔径达到50～300nm。2 . The ultra-compliant nickel-titanium alloy intracranial vascular stent with a micro-nano structure according to claim 1 , wherein the surface of the intracranial vascular stent has a porous micro-nano structure, and the pore size of the micro-nano structure reaches 50-300 nm. 3 .3.按照权利要求2所述的具有微纳结构的超柔顺镍钛合金颅内血管支架，其特征在于，微纳结构的制备方式为：将颅内血管支架浸泡在酸溶液体系中，室温下加电压，进行脱合金处理30min～120min；其中，酸溶液体系为硝酸，浓度为1～3mol/L，电压为1.5V～4.5V。3. The ultra-compliant nickel-titanium alloy intracranial vascular stent with micro-nano structure according to claim 2, wherein the preparation method of the micro-nano structure is: the intracranial vascular stent is immersed in an acid solution system, and at room temperature Voltage is applied to carry out dealloying treatment for 30min-120min; wherein, the acid solution system is nitric acid, the concentration is 1-3mol/L, and the voltage is 1.5V-4.5V.4.按照权利要求1所述的具有微纳结构的超柔顺镍钛合金颅内血管支架，其特征在于，颅内血管支架开环结构由沿周向排布12个周期的第一V字形单元与沿周向排布8个周期的第二V字形单元通过第一连接杆连接形成；闭环结构由沿周向排布8个周期的第二V字形单元通过第二连接杆连接形成；第一V字形单元长度尺寸与宽度尺寸比为0.84，丝宽为0.03～0.05mm；第二V字形单元长度尺寸与宽度尺寸比为0.6～0.7，丝宽为0.05～0.07mm；第二连接杆高度a为0.05±0.01mm，第二连接杆宽度b为0.05±0.01mm；第一连接杆高度c为0.06±0.01mm，第一连接杆宽度d为0.0857±0.01mm。4. The ultra-compliant nickel-titanium alloy intracranial vascular stent with a micro-nano structure according to claim 1, wherein the open-loop structure of the intracranial vascular stent is composed of the first V-shaped units arranged in the circumferential direction for 12 cycles The second V-shaped unit arranged in the circumferential direction for 8 cycles is connected and formed by the first connecting rod; the closed-loop structure is formed by connecting the second V-shaped unit arranged in the circumferential direction for 8 cycles through the second connecting rod; the first The ratio of the length and width of the V-shaped unit is 0.84, and the wire width is 0.03-0.05mm; the ratio of the length and width of the second V-shaped unit is 0.6-0.7, and the wire width is 0.05-0.07mm; the height of the second connecting rod is a is 0.05±0.01mm, the width b of the second connecting rod is 0.05±0.01mm; the height c of the first connecting rod is 0.06±0.01mm, and the width d of the first connecting rod is 0.0857±0.01mm.5.按照权利要求4所述的具有微纳结构的超柔顺镍钛合金颅内血管支架，其特征在于，开环自由端圆角半径为0.05～0.07mm，过渡圆角半径为0.02±0.01mm。5. The ultra-compliant nickel-titanium alloy intracranial vascular stent with micro-nano structure according to claim 4, wherein the open-loop free end fillet radius is 0.05-0.07mm, and the transition fillet radius is 0.02±0.01mm .6.按照权利要求1或4所述的具有微纳结构的超柔顺镍钛合金颅内血管支架，其特征在于，颅内血管支架开环结构与闭环结构采用均匀分布的方式，即在颅内血管支架表面均匀增加开环结构单元，开环结构单元占整个颅内血管支架表面积的20％～40％。6. The super-compliant nickel-titanium alloy intracranial vascular stent with a micro-nano structure according to claim 1 or 4, wherein the open-loop structure and the closed-loop structure of the intracranial vascular stent are uniformly distributed, that is, in the intracranial The surface of the blood vessel stent is uniformly increased with open-loop structural units, and the open-loop structural units account for 20% to 40% of the surface area of the entire intracranial blood vessel stent.7.按照权利要求1或4所述的具有微纳结构的超柔顺镍钛合金颅内血管支架，其特征在于，颅内血管支架长度为15～40mm，颅内血管支架标称直径为2.5～4.5mm，壁厚为0.05～0.085mm；颅内血管支架的两端顶点设置显影杆，显影杆长度为0.5～1.0mm，显影杆宽度为0.15±0.05mm。7 . The ultra-compliant nickel-titanium alloy intracranial vascular stent with a micro-nano structure according to claim 1 or 4, wherein the intracranial vascular stent has a length of 15 to 40 mm and a nominal diameter of the intracranial vascular stent of 2.5 to 2.5 mm. 4.5mm, the wall thickness is 0.05-0.085mm; the two ends of the intracranial vascular stent are provided with developing rods, the length of the developing rod is 0.5-1.0 mm, and the width of the developing rod is 0.15±0.05 mm.8.按照权利要求1或4所述的具有微纳结构的超柔顺镍钛合金颅内血管支架，其特征在于，颅内血管支架基底为超弹性镍钛合金材料，其弹性范围为10％～15％；颅内血管支架显影杆为铂铱合金。8. The ultra-compliant nickel-titanium alloy intracranial vascular stent with micro-nano structure according to claim 1 or 4, wherein the base of the intracranial vascular stent is a superelastic nickel-titanium alloy material, and its elasticity range is 10%～10% 15%; The imaging rod of the intracranial vascular stent is platinum-iridium alloy.

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