Intracranial vascular stent with excellent flexibility
Technical Field
The invention belongs to the technical field of medical instruments, and particularly relates to an intracranial vascular stent with excellent flexibility.
Background
Intracranial blood vessels are often positioned in the subarachnoid space and surrounded by cerebrospinal fluid, and the blood vessels are high in fragility and easy to break during conveying and placing of the stent; meanwhile, a plurality of physiological curves exist in the intracranial blood vessel, and the stent is placed at the curve section, so that the probability of occurrence of a blood vessel straightening effect and poor stent adherence is higher, and a thromboembolic event and in-stent restenosis are easily induced. The physiological characteristics of intracranial blood vessels require that the stent has extremely high flexibility.
The inventor uses the coronary artery drug eluting stent to treat intracranial artery stenosis, but the intracranial vertebral basilar artery has tortuous vessels, thin tube wall, poor elasticity and poorer flexibility than the bare stent. The stent system has poor trafficability, damages the intima of the blood vessel, and causes complications. In order to meet the requirements of patients, intracranial stents have come into use, and are mainly used for treating intracranial atherosclerosis or intracranial aneurysm. Like coronary stents, intracranial stents also have both balloon-expandable and self-expandable types, depending on the form of deployment.
From the clinical point of view, the ball expanding type bracket is hard, has slightly poor trafficability characteristic and is not suitable for cerebral vessels with serious tortuosity; but if the affected part can be reached smoothly, the effect is immediately realized. The self-expanding stent is soft and good in trafficability, but before the stent is implanted, a balloon needs to be used for pre-expanding a lesion part, the balloon and the stent need to be coaxially exchanged, so that the operation is more complicated, and meanwhile, the self-expanding stent has the defect of higher residual stenosis.
The saccule expanding intracranial vascular stent adopts a structure of a support ring and a connecting rib. The support is formed by cutting a thin-wall circular tube through laser hollow-out, and the support ring and the connecting ribs are integrated; after the blood vessel is implanted into a bent blood vessel, the bent shape of the blood vessel is adapted through the plastic deformation of the connecting ribs. The improvement of the flexibility of the product is always a bottleneck in the development and application of the product.
Therefore, the design of a novel intracranial vascular stent structure can improve the flexibility of the balloon expandable stent while keeping the advantages of the balloon expandable stent, and is urgent and significant work.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide an intracranial vascular stent with excellent flexibility, which has excellent flexibility and good biomechanical properties such as grippability, supportability, fatigue life, biocompatibility and the like.
The technical scheme is as follows: in order to achieve the purpose, the invention adopts the following technical scheme:
an intracranial vascular stent with excellent flexibility comprises a plurality of groups of support ring units which are longitudinally arranged, wherein adjacent support ring units are connected through connecting ribs; each support ring unit comprises a plurality of support rings, each support ring is omega-shaped, and the omega-shaped support rings are sequentially connected end to end; the top of each support ring and the joint of the adjacent support rings are round corners of the support ring unit, and through holes are formed in the round corners of the support ring unit; after the two sides of the connecting rib are inserted into the through holes, the connecting rib is deformed and locked with the through holes to form revolute pair connection.
Before assembly, the connecting rib comprises a connecting main body and two connecting end parts, wherein the connecting main body is S-shaped; during assembly, the connecting ribs and the support ring are arranged in an environment at-10 ℃, the connecting end parts are subjected to martensite phase transformation, and the two connecting end parts are inserted into the through holes; after assembly, in a normal temperature environment, the connecting end parts are transformed from martensite to austenite, and the two connecting end parts are excited to be transformed into the lock catches to form locking.
The diameter of the through hole is 0.04 mm-0.06 mm; the diameter of the connecting rib is equal to the reference size of the diameter of the through hole on the support ring unit body, and the matching mode is clearance fit.
The support ring unit is formed by laser hollow cutting of a thin-wall circular tube, and the connecting ribs are formed by shaping and processing shape memory alloy.
The axial length of the support ring unit is 0.5-2 mm; the length of the connecting rib is 0.5-1 mm; the rib width of the connecting rib is 60-200 μm, and the rib width of the support ring is 60-160 μm.
The intracranial vascular stent with excellent flexibility has the transverse length of 8-40 mm, the outer diameter of 1.60-2.00 mm and the wall thickness of 0.06-0.12 mm.
The number of the support rings included in each support ring unit is 6-16.
The invention principle is as follows: the support ring + connecting rib structure is adopted as a main structure of the support, but the structure of the support is obviously different from that of the support with the existing support ring + connecting rib structure: traditional "support ring + splice bar" structural support forms through laser fretwork processing thin wall pipe, and support ring and splice bar are integrative, after implanting the crooked blood vessel, through the plastic deformation of splice bar, adapt to the crooked form of blood vessel. The intracranial vascular stent of the invention consists of n groups of support rings 1 and n-1 groups of connecting ribs, wherein the support rings and the connecting ribs are not integrally formed but are mutually independent. The end parts of the support rings are provided with through holes, and the connecting ribs form revolute pair connection with the through holes on the support rings on two sides through self geometric structures.
Has the advantages that: compared with the prior art, the intracranial vascular stent with excellent flexibility adopts a hinge connection mode, the support ring and the connecting ribs can flexibly and freely rotate, the advantages of the expansion type vascular stent are kept, the flexibility of the stent is greatly improved, and the problem that the flexibility of the existing expansion type intracranial vascular stent product is insufficient is solved.
Drawings
FIG. 1 is a sectional and expanded schematic view of an intracranial vascular stent;
FIG. 2 is a schematic view of the support ring unit and the connection rib unit;
FIG. 3 is a view showing the construction of the joint bars before locking;
FIG. 4 is a top view of a connector bar;
FIG. 5 is a front view of a connector bar;
fig. 6 is an isometric view of a connector bar.
Detailed Description
In order to further illustrate the present invention, the following detailed description is given with reference to examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention.
As shown in fig. 1-6, the reference numerals are as follows: the support ring unit comprises a support ring unit 1, connecting ribs 2, through holes 11, support ring unit round corners 12, connecting end parts 21, connecting bodies 22 and lock catches 23. Wherein, the axial length of the support ring unit 1 is A, and the range is 0.5-2 mm; the length of the connecting rib 2 is B, and the range is 0.5-1 mm; the rib width of the connecting rib 2 is C and ranges from 60 to 200 mu m, and the rib width of the support ring is D and ranges from 60 to 160 mu m.
According to different specifications of specific clinical application, the transverse length of the intracranial vascular stent is 8 mm-40 mm, the outer diameter (the diameter of the outer ring of the cylinder which is formed by curling the figure 1 into the cylinder by taking the transverse direction as the axis direction) of the intracranial vascular stent is 1.60-2.00 mm, and the wall thickness (the thickness of the support ring) of the intracranial vascular stent is 0.06 mm-0.12 mm.
An intracranial vascular stent with excellent flexibility comprises a plurality of groups of support ring units 1 which are longitudinally arranged, and adjacent support ring units 1 are connected through connecting ribs 2. In the longitudinal direction, the connecting ribs 2 are arranged at intervals.
Each support ring unit 1 comprises a plurality of support rings, each support ring is in an omega shape, the omega-shaped support rings are sequentially connected end to end, and adjacent support rings are combined in a mode that wave crests and wave troughs are opposite; the top of each support ring and the joint of the adjacent support rings are support ring unit round corners 12, and through holes 11 are arranged at the support ring unit round corners 12. Wherein, the number of the support rings included in each support ring unit 1 is 6-16.
The support ring unit 1 is formed by laser hollow cutting of a thin-wall circular tube, and the connecting ribs 2 are formed by shaping and processing shape memory alloy. After the two sides of the connecting rib 2 are inserted into the through hole 11, the connecting rib is deformed and locked with the through hole 11 to form revolute pair connection. The diameter of the through hole 11 is 0.04 mm-0.06 mm; the diameter of the connecting rib 2 is equal to the reference size of the diameter of the through hole 11 on the support ring unit body, and the matching mode is clearance fit.
Before assembly, the connecting rib 2 is structured as shown in fig. 3, and includes a connecting main body 22 and two connecting end portions 21, wherein the connecting main body 22 is S-shaped; during assembly, the two connecting ends 21 are inserted into the through hole 11; after assembly, the two connecting ends 21 are activated to deform by a change in temperature, the two connecting ends 21 deforming into the configuration of the catch 23, forming a locked, locked configuration, as shown in fig. 4-6. Two adjacent groups of connecting ribs 2 adopt a staggered arrangement form.
The connecting end portion 21 is subjected to shape change by austenite and martensite transformation under temperature excitation using a shape memory alloy. By the heat-setting process, the connective end 21 has the structure of fig. 3 in the martensite phase and the shackle 23 of fig. 4-6 in the austenite phase below the connective end 21. Therefore, during assembly, the connecting rib 2 and the support ring are placed in a low-temperature environment (-10 ℃ -10 ℃), and the connecting end part 21 undergoes martensite phase transformation to be in the state of fig. 3; in a normal temperature environment (20-40 ℃), the connecting end part 21 is transformed from martensite to austenite, and the connecting end part 21 is transformed into the lock 23 shown in the figures 4-6 to finish locking.