A test bench and method for testing the recoil force of a vascular stent graft

Abstract

The present invention relates to a test bench and method for testing the restoring force of a vascular stent graft. The test bench comprises: a fixing assembly for adjusting and fixing the vascular stent graft to be tested; a testing assembly for bending the vascular stent graft to be tested and measuring the angle and force; a constant temperature water bath (7) for simulating the real application environment of the vascular stent graft; and a platform bracket (8) for assembling, connecting and fixing the above components. Compared with the prior art, the present invention can dynamically test the restoring force of the vascular stent graft, accurately reflect the supporting performance of the stent graft, and has a simple equipment structure, low friction, and few factors affecting the experimental results, and can simulate the real application environment.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a test bench and method for testing the recoil force of a vascular covered stent. Background Art

[0002] Aortic vascular disease, especially vascular dissection and hemangioma, is a disease that seriously endangers the life safety of patients. Endovascular repair (EVAR) is the most widely used treatment for aortic aneurysm. Compared with traditional surgical operations, the most prominent feature of endovascular isolation is minimally invasive, without the surgical trauma of thoracotomy and laparotomy and the pathophysiological interference caused by blocking the aorta. Its principle: Cover the stent with autologous blood vessels, biomaterials or synthetic materials, implant the covered stent into the aortic aneurysm cavity through the delivery system, separate the hemangioma from the blood flow, rebuild a new blood flow channel, and make the hemangioma shrink and ossify after there is no blood flow in the hemangioma, thereby achieving the treatment purpose. EVAR has the characteristics of minimally invasive, high safety, low mortality and low morbidity. Patients recover quickly after surgery, providing more treatment opportunities for elderly and weak patients.

[0003] The vascular stent graft is the main part of the endovascular isolation treatment of aneurysms and arterial dissections. It is used to isolate the diseased segment from the normal blood flow, thereby avoiding the occurrence of serious consequences such as aneurysm rupture, increased congestion of arterial dissections and vascular rupture. When the vascular stent graft is placed in a vascular part with a large curvature in the human body, many complications may occur due to the large rigidity of the vascular stent graft itself. When Stanford B type aortic dissection occurs, it is usually necessary to place and fix one end of the vascular stent graft in the aortic arch with a large curvature. Clinical long-term results show that new ruptures may occur in the vascular wall at both ends of the vascular stent graft. The occurrence of this new rupture may be related to the vascular stent graft being in a curved state. The curved vascular stent graft has a tendency to rebound to a straightened state, and a straightening force acting vertically on the vascular wall is generated at both ends. In addition, during the surgical process of endovascular isolation treatment, when the vascular stent graft is transported in the curved vascular system of the human body, the stent graft also needs to have good bending performance, so as to improve the operability of the operation and ensure the smooth progress of the operation. Therefore, the vascular covered stent needs to have excellent bending performance, and the evaluation of its bending force and straightening force is essential.

[0004] Through the reference of domestic and foreign literature and data, it is found that the main work for the straightening force of vascular stent grafts is to establish a finite element model for numerical simulation or to test the static straightening force in vitro. However, there are still some problems with the existing evaluation methods. For example, the finite element simulation method is used to study the bending force and straightening force of the stent graft. It is necessary to first establish a model for the stent graft and give the material certain mechanical properties. Since the stent graft is fixedly combined by sutures, the metal stent part and the fabric coating part are relatively fixed, but there may also be some relative displacement under the action of force, which is difficult to achieve in finite element simulation. In addition, in order to obtain more realistic data results, it is also necessary to establish a structural and mechanical model of the host blood vessel outside the stent graft, and use a solid-solid coupling method for calculation and simulation, which will greatly increase the difficulty of calculation. In addition, the test method of the straightening force involved in the current literature is usually performed statically at a certain angle, that is, the stent graft is first artificially bent to a specific angle, and then the force value is measured by a dynamometer or other instrument. The defect of this test method is that the test stability is poor, it is greatly affected by the surrounding environment and human factors, and the efficiency is low. There is no report in the prior art on the literature of continuous dynamic testing of the recoil force of vascular covered stents in vitro. Therefore, there is an urgent need for a dynamic testing device for the recoil force of vascular covered stents to overcome the above-mentioned defects. Summary of the invention

[0005] The purpose of the present invention is to provide a test bench and method for testing the recoil force of a vascular covered stent.

[0006] The purpose of the present invention can be achieved by the following technical solution: A vascular stent graft straightening force test bench, comprising:

[0007] A fixing assembly for adjusting and fixing the blood vessel covered stent to be tested, comprising a balancing rotary block, a U-shaped cantilever rod and a slider, wherein the blood vessel covered stent to be tested is connected to the balancing rotary block, the balancing rotary block is arranged on the U-shaped cantilever rod, and the U-shaped cantilever rod is connected to the slider;

[0008] A test assembly for bending a vascular stent to be tested and measuring its angle and force, comprising a slide table, an angle scale and a dynamometer, wherein the slide table is connected to the dynamometer, the other end of the dynamometer is connected to a U-shaped cantilever rod, and the angle scale is arranged on the U-shaped cantilever rod;

[0009] A constant temperature water bath used to simulate the real application environment of vascular covered stents;

[0010] A platform bracket is used to assemble, connect and fix the above components.

[0011] Preferably, the slide is a double-track electric linear slide, the dynamometer is an electronic digital dynamometer, and the double-track electric linear slide can drive the electronic digital dynamometer to move slowly and uniformly.

[0012] Preferably, the fixing assembly includes two U-shaped cantilever rods, the slider includes a first slider and a second slider, the two U-shaped cantilever rods are respectively arranged on the first slider and the second slider, each U-shaped cantilever rod is provided with a balancing rotary block, and the two ends of the vascular coated stent to be tested are respectively connected to a balancing rotary block.

[0013] Further preferably, a force transmission rod is provided on the U-shaped cantilever rod located at one end of the blood vessel covered stent to be tested, and the force transmission rod is connected to a force gauge.

[0014] Preferably, the balancing rotating block has a protruding structure, and the blood vessel covered stent to be tested is sleeved on the protruding structure.

[0015] Preferably, the balancing rotating block has a symmetrical structure. The balancing rotating block has a symmetrical structure and can balance its own gravity.

[0016] Preferably, a pointer for reading the angle is provided on the balancing rotary block. Preferably, the pointer should be as slender and light as possible to reduce relative error.

[0017] Preferably, the balancing rotary block is provided with a through hole for allowing the liquid in the constant temperature water bath to freely flow in and out of the blood vessel covered stent to be tested.

[0018] Preferably, the slider is arranged on a slide rail, and the U-shaped cantilever rod realizes horizontal movement and fixation through the slider and the slide rail. Preferably, the slide rail is a controllable slide rail fixed on the platform bracket. The controllable slide rail includes an electric slide rail whose movement is controlled by a controllable stepping motor.

[0019] Preferably, a scale groove is provided on the U-shaped cantilever rod, and the angle scale is embedded in the scale groove.

[0020] Preferably, the U-shaped cantilever rod is provided with a through hole for connecting the balancing rotary block, and the balancing rotary block and the U-shaped cantilever rod are connected by a bearing. Preferably, the bearing should be as precise as possible to reduce friction, and a ball bearing can be used.

[0021] Preferably, the constant temperature water bath is a transparent and temperature-adjustable controllable constant temperature water bath, and the highest water level of the constant temperature water bath must completely cover the film-covered stent to be tested.

[0022] Preferably, the balancing knob is marked with a standard line for reference when the vascular covered stent to be tested is installed.

[0023] A method for testing the recoil force of a vascular stent graft, using the above-mentioned test platform, specifically includes:

[0024] S1: No-load zeroing: without placing the vascular covered stent to be tested, the dynamometer is driven to move at a constant speed by the slide table, the dynamometer reading is tested and recorded, and the dynamometer is zeroed;

[0025] S2: Place the vascular covered stent to be tested, respectively sleeve the two ends of the vascular covered stent to be tested on the balance rotary block, fix the first slider, and after the constant temperature water bath is filled with water and preheated, drive the dynamometer to approach the first slider at a uniform speed through the slide, and the dynamometer pushes the force transmission rod to approach the first slider, thereby driving the U-shaped cantilever rod and the balance rotary block to approach the first slider;

[0026] S3: Bend the stent graft to be tested to the required degree, record the reading of the dynamometer, and obtain F 测 , record the reading of the angle scale, recorded as θ;

[0027] S4: The restoring force F of the vascular covered stent is calculated according to the following formula 回 :

[0028]

[0029] Wherein, α is the angle between the midpoint of the contact part between the vascular covered stent and the balance block and the line connecting the rotation center and the midline of the balance block, and β is the difference between θ and α.

[0030] The present invention provides a vascular covered stent recoil force test bench and method based on the defects of the existing vascular covered stent recoil force test experimental device, such as being unable to perform dynamic test on the vascular covered stent, only indirectly reflecting the supporting performance of the stent, having a complex equipment structure, having factors such as obvious friction that significantly affect the experimental results, and being unable to simulate the actual application environment.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. The test bench of the present invention can dynamically test the restoring force of the vascular covered stent, accurately reflect the supporting performance of the stent, and has a simple structure, small friction, and small factors affecting the experimental results, and can simulate the real application environment;

[0033] 2. The present invention can flexibly adjust and fix the vascular stent to be tested, as well as perform bending, angle and force tests through the cooperation of the fixing component and the testing component. The operation is simple, the repeatability is strong, and the results are accurate.

[0034] 3. The fixing assembly of the present invention can facilitate the installation, disassembly and testing of the vascular stent to be tested through the coordinated design of the balancing block, the U-shaped cantilever rod and the slider. The balancing block is connected to the U-shaped cantilever rod through a bearing, and overcomes its own gravity through a symmetrical structure, and eliminates the influence of the liquid on the stent through the through hole, which can accurately reflect the bending degree of the vascular stent to be tested and improve the accuracy of the straightening force test;

[0035] 4. The present invention can minimize the influence of the balancing block on the performance of the vascular stent graft itself by setting the protruding structure on the balancing block, while achieving the test process of fixing and bending the vascular stent graft to be tested, accurately reflecting the supporting performance of the vascular stent graft, and improving the accuracy of the experimental results;

[0036] 5. The test assembly of the present invention accurately tests the friction between the slider and the slide rail and the angle between the center line of the balance block and the horizontal plane through the coordinated design of the slide table, the dynamometer and the angle scale, so as to obtain the straightening force of the vascular stent graft;

[0037] 6. The constant temperature water bath of the present invention can simulate the actual temperature and liquid environment of the vascular covered stent applied in the human body, so as to improve the accuracy of the experimental results. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the overall structure of the test bench of the present invention;

[0039] Figure 2 This is a schematic diagram of the structure of the test bench of the present invention without the constant temperature water bath;

[0040] Figure 3 It is a structural schematic diagram of a U-shaped cantilever rod;

[0041] Figure 4 It is the structural schematic diagram of the balancing rotating block;

[0042] Figure 5 It is a schematic diagram of the connection between the U-shaped cantilever rod and the balancing rotating block;

[0043] Figure 6 This is a schematic diagram for deriving the formula for calculating the straight-back force;

[0044] In the figure: 1-balanced rotary block, 11-protrusion structure, 12-through hole, 2-U-shaped cantilever rod, 21-scale groove, 3-slider, 31-first slider, 32-second slider, 4-slide, 5-angle scale, 6-dynamometer, 7-constant temperature water bath, 8-platform bracket, 9-force transmission rod, 10-slide rail, 13-bearing, 100-vascular coated stent, A-midpoint of the contact part of the vascular coated stent 100 and the balancing rotary block 1, O-rotation center, LL-midline of the balancing rotary block 1. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0046] Example 1

[0047] A test bench for testing the recoil force of a vascular stent graft, such as Figures 1-2 As shown, it includes an electronic digital display dynamometer 6, a double-track electric linear slide 4, a U-shaped cantilever rod 2, a slide rail 10, a slider 3, an angle scale 5, a balancing rotary block 1, a platform bracket 8, a force transmission rod 9, a constant temperature water bath 7, and a ball bearing 13.

[0048] like Figure 1 As shown, after the platform bracket 8 is built, the platform bracket 8 is placed in the constant temperature water bath 7 to form the basic frame of this embodiment, and the following components are assembled on this basic frame.

[0049] like Figures 2-3 As shown, the blood vessel stent graft 100 to be tested is fixed by two left and right balancing blocks 1, and a scale groove 21 is designed on the U-shaped cantilever rod 2, and an angle scale 5 is placed in the groove. The left and right balancing blocks 1 are respectively arranged on the left and right U-shaped cantilever rods 2, and the slider 3 includes a first slider 31 and a second slider 32 on the left side. The left U-shaped cantilever rod 2 is fixed on the first slider 31, and the right U-shaped cantilever rod 2 is fixed on the second slider 32. The sliders 31 and 32 are both arranged on the slide rail 10, and the slide rail 10 is fixed on the platform bracket 8. A force transmission rod 9 is fixed on the top of the right U-shaped cantilever rod 2, and a dynamometer 6 is connected to the right side of the force transmission rod 9, and the dynamometer 6 is connected to the slide 4.

[0050] like Figure 4 As shown, the balancing block 1 is provided with a protrusion structure 11 for the tested blood vessel stent graft 100 to be sleeved thereon, and in order to balance its own gravity, the protrusion structure 11 is symmetrically arranged on both sides of the balancing block 1. The protrusion structure 11 is also provided with a through hole 12 for the liquid in the constant temperature water bath 7 to freely enter and exit the tested blood vessel stent graft 100.

[0051] like Figure 5 As shown, the U-shaped cantilever rod 2 and the balancing rotary block 1 are connected by a ball bearing 13 .

[0052] A method for testing the recoil force of a vascular stent graft comprises the following steps:

[0053] S1: No-load zeroing. When no vascular covered stent 100 to be tested is placed, the electronic digital dynamometer 6 is driven by the double-track electric linear slide 4 to move slowly and uniformly, and the friction force generated by the contact between the slider 32 and the slide rail 10 is tested and recorded. The dynamometer zeroing is completed.

[0054] S2: Place the vascular stent graft 100 to be tested, and respectively sleeve the two ends of the vascular stent graft 100 to be tested on the protruding structures 11 of the left and right balancing rotary blocks 1, fix the first slider 31, and after the constant temperature water bath 7 is filled with water and preheated, control the double-track electric linear slide 4 to move slowly and uniformly to the left, drive the electronic digital display dynamometer 6 to push the force transmission rod 9 and the U-shaped cantilever rod 2 at the bottom and the corresponding balancing rotary block 1 to bend the vascular stent graft 100 to the required degree, and record the reading F of the electronic digital display dynamometer 6 测 And the reading angle θ of the angle scale 5, and according to the function formula:

[0055]

[0056] Further calculate the support's straightening force F 回 , thereby determining the compliance of the vascular stent.

[0057] Among them, β = θ-α. Figure 6 As shown, θ is the angle between the center line LL of the balancing block 1 and the horizontal plane, and α is the angle between the line connecting the midpoint A of the contact part between the vascular covered stent 100 and the balancing block 1 and the rotation center O and the center line LL of the balancing block 1.

[0058] Example 2

[0059] A test bench for testing the recoil force of a vascular stent graft is provided, and a standard line is marked on a balancing block 1 for reference when the vascular stent graft 100 to be tested is sheathed. The standard line is used to determine the sheathing depth of the vascular stent graft 100 to be tested in each experiment (i.e., the length of the contact portion between the vascular stent graft 100 and the balancing block 1), so as to determine the position of the contact midpoint A between the vascular stent graft 100 to be tested and the balancing block 1 in the derivation of the calculation formula, thereby determining the angle α between the line connecting the contact midpoint A of the stent graft and the balancing block and the rotation center O and the midline LL of the balancing block, so as to simplify the experimental steps. The remaining structure is the same as that of Example 1.

[0060] A method for testing the restoring force of a vascular stent graft is provided. When placing a vascular stent graft 100, the two ends of the vascular stent graft 100 to be tested are respectively placed on the protruding structures 11 of the left and right balancing blocks 1, and the edge of the vascular stent graft 100 to be tested is aligned with the standard line on the balancing block 1. The remaining steps are the same as those in Example 1.

[0061] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A test bench for testing the recoil force of a vascular stent graft, characterized in that: include: A fixing assembly for adjusting and fixing a covered stent of a blood vessel to be tested, comprising a balancing rotary block (1), a U-shaped cantilever rod (2) and a sliding block (3); the covered stent of the blood vessel to be tested is connected to the balancing rotary block (1); the balancing rotary block (1) is arranged on the U-shaped cantilever rod (2); and the U-shaped cantilever rod (2) is connected to the sliding block (3); A test assembly for bending a blood vessel covered stent to be tested and measuring its angle and force, comprising a slide table (4), an angle scale (5) and a dynamometer (6), wherein the slide table (4) is connected to the dynamometer (6), the other end of the dynamometer (6) is connected to a U-shaped cantilever rod (2), and the angle scale (5) is arranged on the U-shaped cantilever rod (2); A constant temperature water bath (7) for simulating the actual application environment of the vascular stent graft; A platform bracket (8) for assembling, connecting and fixing the above-mentioned components; The fixing assembly comprises two U-shaped cantilever rods (2), the slider (3) comprises a first slider (31) and a second slider (32), the two U-shaped cantilever rods (2) are respectively arranged on the first slider (31) and the second slider (32), each U-shaped cantilever rod (2) is provided with a balancing rotary block (1), and both ends of the blood vessel covered stent to be tested are respectively connected to a balancing rotary block (1); A force transmission rod (9) is provided on the U-shaped cantilever rod (2) located at one end of the blood vessel covered stent to be tested, and the force transmission rod (9) is connected to the force gauge (6); The experimental method for testing the recoil force of a vascular stent graft using the test experimental platform specifically includes: S1: no-load zeroing, without placing the vascular covered stent to be tested, driving the dynamometer (6) to move at a constant speed through the slide table (4), testing and recording the dynamometer reading, and zeroing the dynamometer; S2: placing the covered stent of the blood vessel to be tested, respectively sleeve the two ends of the covered stent of the blood vessel to be tested on the balancing rotary block (1), fixing the first sliding block (31), and after the constant temperature water bath (7) is filled with water for preheating, driving the dynamometer (6) to approach the first sliding block (31) at a uniform speed through the slide table (4), the dynamometer (6) pushes the force transmission rod (9) to approach the first sliding block (31), and then drives the U-shaped cantilever rod (2) and the balancing rotary block (1) to approach the first sliding block (31); S3: bend the stent graft to be tested to the required degree, record the reading of the dynamometer (6), and obtain F 测 , record the reading of the angle scale (5), denoted as θ; S4: The restoring force F of the vascular covered stent is calculated according to the following formula 回 : Wherein, α is the angle between the line connecting the midpoint (A) of the contact part of the vascular covered stent and the balancing block (1) and the rotation center (O) and the midline (LL) of the balancing block, and β is the difference between θ and α.

2. The vascular stent graft restoring force test bench according to claim 1 is characterized in that: The balancing rotary block (1) is provided with a protruding structure (11), and the blood vessel covered stent to be tested is sleeved on the protruding structure (11).

3. The vascular stent graft restoring force test bench according to claim 1 is characterized in that: The balancing rotating block (1) has a symmetrical structure.

4. The vascular stent graft straightening force test bench according to claim 1, characterized in that: The balancing rotary block (1) is provided with a pointer for reading the angle.

5. The vascular stent graft restoring force test bench according to claim 1, characterized in that: The balancing rotary block (1) is provided with a through hole (12) for allowing the liquid in the constant temperature water bath (7) to freely flow in and out of the blood vessel covered stent to be tested.

6. The vascular stent graft restoring force test bench according to claim 1, characterized in that: The sliding block (3) is arranged on the sliding rail (10), and the U-shaped cantilever rod (2) is horizontally moved and fixed through the sliding block (3) and the sliding rail (10).

7. The vascular stent graft restoring force test bench according to claim 1, characterized in that: The U-shaped cantilever rod (2) is provided with a scale groove (21), and the angle scale (5) is embedded in the scale groove (21); the U-shaped cantilever rod (2) is provided with a through hole for connecting the balancing rotary block (1), and the balancing rotary block (1) and the U-shaped cantilever rod (2) are connected by a bearing (13).

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