A preoperative vascular dilation training device for dialysis arteriovenous fistula surgery

Abstract

This invention discloses a preoperative vascular dilation training device for dialysis arteriovenous fistula surgery, comprising: a support base with a cylindrical cavity; a sealed fluid-filled sac disposed within the cavity of the support base, the inner surface of which is adapted to conform to the forearm skin; an incompressible fluid filling the cavity of the sealed fluid-filled sac; a grip force driving component, including a grip ball and a transmission structure linked to the grip ball, the transmission structure communicating with the fluid chamber of the sealed fluid-filled sac for converting the patient's grip force into hydrostatic pressure within the fluid chamber; and a shear stress simulator disposed on the inner surface of the sealed fluid-filled sac, which is a micro-protrusion array structure for converting hydrostatic pressure into an alternating shear strain field in the subcutaneous tissue. This invention generates uniform hydrostatic pressure through grip force driving, achieving directional vascular dilation, while simultaneously utilizing the micro-protrusion array to simulate the postoperative blood flow shear stress environment, promoting vascular adaptive remodeling.

Description

Technical Field

[0001] This invention specifically relates to a preoperative vascular dilation training device for dialysis arteriovenous fistula surgery. Background Technology

[0002] Arteriovenous fistulas (AVFs) are the "lifeline" for maintenance hemodialysis patients, and their postoperative maturation quality directly affects dialysis outcomes. Clinical studies have shown that pre-dilation training of the blood vessels on the limb intended for fistula creation before AVF formation can effectively increase the vessel diameter and blood flow, thereby improving the postoperative maturation rate of the fistula.

[0003] Currently, the commonly used preoperative vascular training methods in clinical practice mainly include the following: (a) Grip ball training method. Patients exercise their forearm muscles by repeatedly gripping an elastic ball, which indirectly promotes venous return. However, this method has the following drawbacks: the main target of stimulation is muscle tissue rather than the blood vessel wall, resulting in limited and unidirectional dilation stimulation of the blood vessels; the training intensity is difficult to quantify, leading to poor patient compliance; and it cannot simulate the shear stress environment of blood flow on the blood vessel wall after arteriovenous fistula surgery.

[0004] (II) Blood Pressure Cuff Inflation Method. This method involves periodically inflating the upper arm with a blood pressure cuff to induce venous dilation through external pressure. The drawbacks of this method are: the cuff expands in a cylindrical shape after inflation, resulting in uneven pressure distribution (higher pressure at the edges and lower pressure in the center), which can easily cause local tissue damage; it cannot achieve directional pressure transmission based on the anatomical shape of the forearm; and the constant pressure mode does not conform to vascular physiological adaptation, potentially leading to decreased vascular elasticity with long-term use. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the technical problem to be solved by this invention is to provide a preoperative vascular dilation training device for dialysis arteriovenous fistula surgery. This device allows patients to convert their grip strength into directional vascular dilation stimulation while simulating the postoperative blood flow shear stress environment, thereby achieving uniform, controllable, and physiologically relevant pre-dilation training of the vessels on the predetermined fistula side.

[0006] To achieve the above objectives, the present invention provides a preoperative vascular dilation training device for dialysis arteriovenous fistula surgery, comprising: The support base has a cylindrical cavity; A sealed liquid bladder is disposed in the cylindrical cavity of the support base. The sealed liquid bladder has an inner cavity, an inner surface, and an outer surface. The inner surface is used to fit against the skin surface of the forearm on the predetermined fistula side. An incompressible fluid is filled into the inner cavity of the sealed liquid bladder; A grip force actuation assembly includes a grip ball and a transmission structure linked to the grip ball. The grip ball is disposed outside a sealed liquid sac and has a hollow inner cavity and an elastic outer wall. The transmission structure communicates with the fluid chamber of the sealed liquid sac. The grip force actuation assembly is used to convert the patient's grip force into hydrostatic pressure within the fluid chamber. A shear stress simulator is disposed on the inner surface of the sealed liquid bladder. The shear stress simulator is a micro-protrusion array structure. The shear stress simulator is used to convert the static pressure applied to the skin surface by the sealed liquid bladder into an alternating shear strain field of the subcutaneous tissue.

[0007] Furthermore, the sealed liquid bladder is a composite structure, including an outer layer, a receiving cavity, and an inner layer; the outer layer is a polyurethane fabric layer; the inner layer is a microstructure layer, the inner layer and the outer layer are arranged opposite to each other and surround the receiving cavity; the micro-protrusion array structure is integrally formed on the inner surface of the inner layer, the incompressible fluid fills the receiving cavity, and the receiving cavity is connected to the transmission structure.

[0008] Furthermore, the transmission structure includes a cylinder, a first elastic reset member, a first piston plate, a first piston rod, a hydraulic cylinder, a second elastic reset member, and a second piston plate; the first piston plate is sealed inside the cylinder and can move along the axial direction of the cylinder, the first piston plate divides the inner cavity of the cylinder into two non-communicating chambers, and the first elastic reset member is connected between the first piston plate and the inner wall of the cylinder; the end of the cylinder near the grip ball is connected to the hollow inner cavity of the grip ball through an air pipe; The second piston plate is sealed inside the cylinder and can move along the axial direction of the cylinder. The second piston plate divides the inner cavity of the cylinder into two non-communicating chambers. The second elastic reset member is connected between the second piston plate and the inner wall of the cylinder. The chamber of the cylinder near the sealed liquid bladder is connected to the inner cavity of the sealed liquid bladder through an oil pipe. The first piston rod is slidably connected between the first piston plate and the second piston plate.

[0009] Furthermore, it also includes a frequency acceleration mechanism; the first piston rod is connected to the second piston plate through the frequency acceleration mechanism; the frequency acceleration mechanism is used to convert the reciprocating motion of the first piston rod into a rapid reciprocating motion and deliver it to the second piston plate.

[0010] Furthermore, the frequency acceleration mechanism includes a second piston rod, a rack, a gear, and a driven disc; the rack is fixedly mounted on the first piston rod; the gear meshes with the rack; the driven disc is sleeved and fixed on the central shaft of the gear, and the outer circumferential surface of the driven disc is provided with a plurality of arc-shaped protrusions spaced circumferentially; one end of the second piston rod is connected to the second piston plate, and the other end of the second piston rod extends out of the oil cylinder and abuts against the outer circumferential surface of the driven disc; when the driven disc rotates, the arc-shaped protrusions push the second piston rod to perform linear reciprocating motion.

[0011] Furthermore, a roller is provided at the end of the second piston rod, and the roller is in rolling connection with the arc-shaped protrusion.

[0012] Furthermore, the micro-protrusion array structure includes multiple micro-protrusions; the multiple micro-protrusions are distributed in an array along the inner surface of the sealed liquid bladder.

[0013] Furthermore, the plurality of micro-protrusions include a first group of micro-protrusions and a second group of micro-protrusions; the first group of micro-protrusions corresponds to the surface projection area of ​​the radial artery and cephalic vein in the human forearm; the second group of micro-protrusions is located in the edge area of ​​the inner surface of the sealed fluid sac and is arranged around the outer periphery of the first group of micro-protrusions; the height of the first group of micro-protrusions is 0.3 mm to 0.5 mm, and the spacing between the first group of micro-protrusions is 1 mm to 2 mm; the height of the second group of micro-protrusions is 0.1 mm to 0.2 mm, and the spacing between the second group of micro-protrusions is 2 mm to 3 mm.

[0014] Furthermore, the incompressible fluid is dimethyl silicone oil.

[0015] Furthermore, a buffer layer is provided between the inner wall of the columnar cavity of the support and the outer surface of the sealed liquid bladder; the buffer layer is a medical-grade sponge layer or a silicone layer.

[0016] The beneficial effects of this invention are: The aforementioned preoperative vascular dilation training device for dialysis arteriovenous fistula surgery has at least the following advantages: 1. This invention utilizes a grip strength driving component, including a grip ball and a transmission structure linked to the grip ball, with the transmission structure connected to the fluid chamber of a sealed fluid-filled bladder. When the patient grips the grip ball, the grip strength is converted into hydrostatic pressure of the fluid within the sealed bladder. This pressure is uniformly transmitted to the entire inner surface of the sealed bladder via the incompressible fluid, and then directly acts on the subcutaneous blood vessel walls through the skin. Compared to existing grip balls that only indirectly stimulate muscles, this invention achieves a directional conversion of grip strength energy from "muscle work" to "vasodilation," significantly improving energy utilization efficiency.

[0017] 2. This invention utilizes a shear stress simulator with a micro-protrusion array structure on the inner surface of a sealed fluid-filled bladder. When the sealed bladder compresses the skin under fluid pressure, the micro-protrusion array creates local indentations on the skin surface and forms an alternating shear strain field in the subcutaneous tissue. The spatial distribution and frequency characteristics of this shear strain field are highly similar to the shear stress environment generated by blood flow on the vessel wall after arteriovenous fistula surgery, thereby activating the mechanotransduction pathways of vascular endothelial cells and promoting vascular adaptive remodeling in the preoperative stage.

[0018] 3. This invention employs a support base to accommodate a sealed fluid bladder, which is filled with incompressible fluid. The pressure applied to the sealed fluid is transmitted in all directions with a constant magnitude. Compared to the uneven pressure distribution problem of existing blood pressure cuff methods, which results in high pressure at the edges and low pressure at the center, this invention can generate uniform hydrostatic pressure dilation stimulation on the forearm vascular bed, avoiding the risk of local tissue damage.

[0019] 4. Synergistic Training of Directional Dilation and Shear Stress Simulation: This invention integrates a grip force driving component and a shear stress simulator, allowing patients to simultaneously complete both directional vascular dilation and shear stress simulation training through a single fist-clenching motion. Compared to existing technologies that require separate training methods, this invention simplifies the training process, improves patient compliance, and ensures that the two training effects synergistically promote the orderly optimization of vascular conditions, creating favorable vascular conditions for arteriovenous fistula surgery. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0021] Figure 1 This is a schematic diagram of a preoperative vascular dilation training device for dialysis arteriovenous fistula provided in an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram at point A in the middle; Figure 3 for Figure 1 The diagram shows the unfolded shear stress simulator in the preoperative vascular dilation training device for dialysis arteriovenous fistula. Figure 4 for Figure 1 The diagram shows a lateral view of the shear stress simulator in the preoperative vascular dilation training device for dialysis arteriovenous fistula. Figure label: 100, Support base; 200, Sealed liquid bladder; 400, Grip force drive assembly; 410, Grip force ball; 420, Transmission structure; 421, Cylinder; 422, First piston rod; 423, Hydraulic cylinder; 430, Frequency acceleration mechanism; 431, Second piston rod; 432, Rack; 433, Gear; 434, Driven disc; 435, Arc-shaped protrusion; 436, Roller; 500, Shear stress simulator; 510, First group of micro-protrusions; 520, Second group of micro-protrusions. Detailed Implementation

[0022] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention; therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Please see Figures 1 to 4 The present invention provides a preoperative vascular dilation training device for dialysis arteriovenous fistula surgery, including a support base 100, a sealed liquid sac 200, an incompressible fluid, a grip force driving component 400, and a shear stress simulator 500.

[0024] The support base 100 is cylindrical in shape, with a cylindrical cavity inside. The support base 100 can be made of medical-grade plastic or lightweight aluminum alloy, and has sufficient structural strength to accommodate and protect the internal components.

[0025] The sealed sac 200 is disposed within the cylindrical cavity of the support 100. The sealed sac 200 itself is a flexible, sealed container with an inner cavity, an inner surface, and an outer surface. During use, the inner surface directly adheres to the skin surface of the forearm on the intended stoma side, covering the area from near the wrist crease to below the elbow crease, focusing on covering the surface projection areas of the radial artery and cephalic vein. The outer surface of the sealed sac 200 contacts the inner wall of the cylindrical cavity of the support 100 or indirectly contacts it through a buffer layer. The sealed sac 200 is made of a biocompatible, flexible polymer material that can deform under external force and uniformly transmit pressure to the skin.

[0026] An incompressible fluid fills the inner cavity of the sealed liquid bladder 200. This fluid is medical-grade dimethyl silicone oil, which has an extremely low compressibility coefficient and can transmit externally applied pressure to the entire inner surface of the sealed liquid bladder 200 with almost no loss. The filling volume is generally 95% to 98% of the inner cavity volume, with a small amount of space reserved to accommodate volume expansion caused by temperature changes.

[0027] The grip force actuation assembly 400 includes a grip ball 410 and a transmission structure 420 linked to the grip ball 410. The grip ball 410 is located outside the closed fluid sac 200, typically at the proximal end of the support base 100 (closer to the patient's hand). The grip ball 410 has a hollow inner cavity and an elastic outer wall, which can be made of silicone or thermoplastic elastomer, allowing for elastic deformation when the patient or healthcare worker grips it with their palm. One end of the transmission structure 420 communicates with the hollow inner cavity of the grip ball 410 (through a trachea), and the other end communicates with the fluid chamber of the closed fluid sac 200. When the patient grips the grip ball 410, the gas inside the grip ball 410 is forced into the transmission structure 420, driving a piston to move and converting the grip force into hydrostatic pressure of the fluid inside the closed fluid sac 200. This hydrostatic pressure is evenly transmitted to the inner surface of the closed fluid sac 200 and then acts on subcutaneous blood vessels through the skin, achieving passive vasodilation.

[0028] A shear stress simulator 500 is disposed on the inner surface of the closed fluid sac 200. This shear stress simulator 500 is a micro-protrusion array structure, i.e., a thin layer composed of multiple tiny protrusions arranged in a specific pattern. When the closed fluid sac 200 compresses the skin under fluid pressure, the micro-protrusion array creates localized indentations on the skin surface. Due to the specially designed height and spacing of the micro-protrusions, they generate an alternating shear strain field in the subcutaneous tissue. The spatial distribution and frequency characteristics of this alternating shear strain field are highly similar to the shear stress environment generated by blood flow on the vessel wall after arteriovenous fistula surgery, thereby simulating postoperative hemodynamic stimulation before surgery and promoting adaptive remodeling of vascular endothelial cells.

[0029] This training device utilizes a support base 100 to provide stable external support, a sealed fluid-filled bladder 200 to achieve anatomical fit with the forearm, and an incompressible fluid to ensure uniform pressure transmission. The grip force drive component 400 converts the patient's active grip force into passive static pressure, and the shear stress simulator 500 converts macroscopic static pressure into microscopic shear strain. The patient achieves directional vasodilation through their own grip on the grip ball 410, while the static pressure applied to the skin surface by the sealed fluid-filled bladder 200 is converted into an alternating shear strain field in the subcutaneous tissue, achieving simulated training of vascular shear stress. Compared to traditional methods of simply using a grip ball to train muscles or using a blood pressure cuff to induce venous dilation, this training device allows for the synergistic implementation of directional dilation and shear stress simulation training, creating favorable vascular conditions for arteriovenous fistula surgery.

[0030] In this embodiment, the sealed liquid bladder 200 is a composite structure, including an outer layer, a receiving cavity, and an inner layer; the outer layer is a polyurethane fabric layer; the inner layer is a microstructure layer, and the inner layer and the outer layer are arranged opposite to each other to form the receiving cavity; the micro-protrusion array structure is integrally formed on the inner surface of the inner layer, and the incompressible fluid is filled in the receiving cavity, which is connected to the transmission structure 420.

[0031] Working principle: When fluid pressure is applied to the sealed liquid bladder 200, the outer layer provides structural support to prevent the bladder from over-expanding and rupturing, while the inner layer further converts the pressure into local indentations and subcutaneous shear strain on the skin through the micro-protrusions on its surface, thus achieving a composite function of "tear resistance, uniform pressure transmission, and micro-morphology".

[0032] In this embodiment, the transmission structure 420 adopts a two-stage gas-liquid linkage structure.

[0033] The transmission structure 420 includes a cylinder 421, a first elastic reset member, a first piston plate, a first piston rod 422, a hydraulic cylinder 423, a second elastic reset member, and a second piston plate. The cylinder 421 is cylindrical, with the first piston plate sealed inside. A sealing ring is installed on the outer periphery of the first piston plate, allowing it to slide axially along the cylinder 421 and dividing the inner cavity of the cylinder 421 into two non-communicating chambers: an air chamber near the grip ball 410 and a large air chamber away from the grip ball 410. The first elastic reset member is a helical compression spring connected between the first piston plate and the inner wall of the cylinder 421, specifically located on the side away from the grip ball 410, providing a reset force after the first piston plate is pushed away from its initial position. The end of the cylinder 421 near the grip ball 410 is connected to the hollow inner cavity of the grip ball 410 via an air pipe.

[0034] The hydraulic cylinder 423 is cylindrical, with a second piston plate sealed inside. The second piston plate also has a sealing ring and can slide axially along the cylinder 423, dividing the cylinder's interior into two non-communicating chambers: an oil chamber near the sealed liquid bladder 200 and an air chamber (or spring chamber) away from the sealed liquid bladder 200. A second elastic reset element, also a helical compression spring, is connected between the second piston plate and the inner wall of the cylinder 423, specifically located on the side away from the sealed liquid bladder 200, providing a reset force after the second piston plate is pushed away. The chamber (oil chamber) of the cylinder 423 near the sealed liquid bladder 200 is connected to the interior of the sealed liquid bladder 200 via an oil pipe.

[0035] The first piston rod 422 is slidably connected between the first piston plate and the second piston plate. One end of the first piston rod 422 is fixedly connected to or abuts against the first piston plate, and the other end is fixedly connected to the second piston plate or connected via the frequency acceleration mechanism 430. In the basic embodiment of this claim, the first piston rod 422 is directly connected to the first piston plate and the second piston plate, so that the two move synchronously.

[0036] Working principle: When the patient grips the grip ball 410, the air inside the hollow cavity of the grip ball 410 is compressed, increasing the pressure. This pressure enters the air chamber of the cylinder 421 through the air tube. The air pressure pushes the first piston plate to move away from the grip ball 410, compressing the first elastic reset member. The first piston plate pushes the second piston plate to move in the same direction via the first piston rod 422, compressing the second elastic reset member. When the second piston plate moves, the incompressible fluid (usually the same dimethyl silicone oil as the sealed liquid bladder 200) in the oil chamber of the cylinder 423 is squeezed and enters the inner cavity of the sealed liquid bladder 200 through the oil tube, causing the sealed liquid bladder 200 to expand. When the patient releases the grip ball 410, the elastic outer wall of the grip ball 410 returns to its original position, creating a negative pressure in the hollow cavity. At the same time, the first and second elastic reset members push the first and second piston plates to reset, increasing the volume of the oil chamber. The fluid in the sealed liquid bladder 200 flows back to the cylinder 423, reducing the pressure.

[0037] Action sequence: Clenching the fist → pneumatic pressure drives the first piston plate → the first piston rod 422 pushes the second piston plate → hydraulic pressure drives the sealed liquid bladder 200 to expand; relieving the fist → the elastic reset element pushes back → fluid flows back → the sealed liquid bladder 200 contracts. This creates a periodic pressure pulse that matches the frequency of clenching the fist.

[0038] Employing a two-stage air-liquid linkage, the air pressure of the grip ball 410 is converted into hydraulic pressure, avoiding pressure loss due to the compressibility of air and improving pressure transmission efficiency. An elastic reset component ensures automatic system reset after the fist is released, allowing the patient to complete the full pressurization-depressurization cycle without additional action. The entire transmission process is purely mechanical, without electronics or pneumatic pumps, ensuring safety and reliability.

[0039] To further improve the training effect, this embodiment adds a frequency acceleration mechanism 430. This frequency acceleration mechanism 430 is disposed between the first piston rod 422 and the second piston plate, that is, the first piston rod 422 is not directly connected to the second piston plate, but indirectly drives the second piston plate through the frequency acceleration mechanism 430.

[0040] The function of the frequency acceleration mechanism 430 is to convert the relatively slow reciprocating motion of the first piston rod 422 (the same frequency as the patient's fist clenching, approximately 30-60 times / minute) into a faster reciprocating motion and deliver it to the second piston plate. Specifically, when the patient clenches and unclenches their fist at a certain frequency, the movement speed of the first piston rod 422 is relatively slow, but after passing through the frequency acceleration mechanism 430, the reciprocating motion frequency of the second piston plate can be several times that of the first piston rod 422 (e.g., 3-5 times). This means that each time the patient clenches their fist, the fluid pressure within the sealed liquid bladder 200 generates multiple rapid pulses, rather than a single pulse.

[0041] Specifically, the frequency acceleration mechanism 430 includes a second piston rod 431, a rack 432, a gear 433, and a driven disc 434. The rack 432 is fixedly mounted on the first piston rod 422 and moves linearly synchronously with it. The length of the rack 432 should be greater than the maximum stroke of the first piston rod 422 to ensure that the rack 432 remains engaged with the gear 433 throughout the entire stroke. The gear 433 meshes with the rack 432. The module and number of teeth of the gear 433 are selected according to the required speed increase ratio. The central shaft of the gear 433 is mounted on a fixed bracket via bearings and can rotate freely.

[0042] The driven disc 434 is mounted and fixed on the central shaft of the gear 433, coaxial with the gear 433 and rotating synchronously. Multiple arc-shaped protrusions 435 are spaced circumferentially on the outer circumferential surface of the driven disc 434. The number of arc-shaped protrusions 435 determines the number of pushes generated per revolution. For example, if three evenly distributed arc-shaped protrusions 435 are provided, the driven disc 434 will push the second piston rod 4313 times per revolution. The contour curve of the arc-shaped protrusions 435 is a smooth arc or an Archimedean spiral to ensure a smooth and impact-free pushing process.

[0043] One end of the second piston rod 431 is fixedly connected to the second piston plate, and the other end of the second piston rod 431 extends out of the end cap of the oil cylinder 423 and abuts against the outer circumferential surface of the driven plate 434. Specifically, a roller 436 or a sliding contact may be provided at the end of the second piston rod 431 to reduce friction with the arc-shaped protrusion 435. A return spring (not shown in the figure) is also sleeved on the axis of the second piston rod 431 to pull the second piston rod 431 back to the initial position after the arc-shaped protrusion 435 has rotated.

[0044] In operation, when the first piston rod 422 moves, the rack 432 drives the gear 433 to rotate, which in turn drives the driven disc 434 to rotate. The arc-shaped protrusions 435 on the outer circumference of the driven disc 434 sequentially contact the end of the second piston rod 431 and push it outwards (i.e., towards the inside of the cylinder 423), thereby pushing the second piston plate to compress the oil chamber. After the arc-shaped protrusions 435 have rotated past, the second piston rod 431 retracts under the action of its own return spring, and the second piston plate retracts accordingly. Due to the continuous rotation of the driven disc 434 and the sequential action of the arc-shaped protrusions 435, the second piston rod 431 produces continuous reciprocating motion. The number of reciprocating motions generated per revolution of the driven disc 434 is equal to the number of arc-shaped protrusions 435.

[0045] The specific action process is as follows: The patient slowly clenches their fist, the first piston rod 422 moves at a constant speed, the rack 432 drives the gear 433 to rotate at a constant speed, and the driven plate 434 rotates at a constant speed. The arc-shaped protrusion 435 on the driven plate 434 pushes the second piston rod 431 to extend rapidly, and the second arc-shaped protrusion 435 pushes immediately afterward, forming a series of continuous pulses. When the first piston rod 422 stops moving, the driven plate 434 stops rotating, and the pulses stop. When the first piston rod 422 moves in the opposite direction (opens the fist), the rack 432 moves in the opposite direction, the gear 433 rotates in the opposite direction, the driven plate 434 rotates in the opposite direction, and the arc-shaped protrusion 435 will also push the second piston rod 431, but at this time the oil chamber is under negative pressure, and the movement direction of the second piston rod 431 is opposite, generating negative pressure pulses.

[0046] The institution transforms patients' slow, natural fist-clenching movements into high-frequency pressure pulses, greatly enhancing the training effect.

[0047] Please see Figure 3 and Figure 4 In this embodiment, the micro-protrusion array structure includes multiple micro-protrusions. These micro-protrusions are distributed in an array along the inner surface of the sealed liquid bladder 200. The array can be a regular rectangular grid, a hexagonal grid, or a concentric ring distribution. Each micro-protrusion is conical, hemispherical, or pyramidal in shape, with a rounded tip to avoid puncturing the skin. The material of the micro-protrusions is the same as the inner layer of the sealed liquid bladder 200, which is medical-grade silicone or thermoplastic polyurethane, possessing a certain degree of elasticity, capable of deforming under pressure and returning to its original shape after pressure is released.

[0048] Working principle: When the sealed fluid bladder 200 compresses the skin under fluid pressure, the tips of the micro-protrusions first contact the skin, creating a local high-pressure zone. As the pressure increases, the micro-protrusions are partially flattened, and the surrounding skin tissue is subjected to radial stretching and shearing. Due to the gaps between the micro-protrusions, the skin experiences less pressure in the gap areas, thus forming periodic pressure and strain gradients on the skin surface and in the subcutaneous tissue. The spatial rate of change of this gradient (i.e., shear strain) is key to simulating postoperative blood flow shear stress.

[0049] By employing a simple micro-protrusion array structure, macroscopic hydrostatic pressure is transformed into microscopic local shear strain, enabling low-cost, passive simulation of the postoperative blood flow shear stress environment. The micro-protrusions, ranging in size from micrometers to millimeters, do not cause patient pain or skin damage. Simultaneously, they effectively activate mechanoreceptors in the skin and subcutaneous tissue, transmitting signals to vascular endothelial cells and promoting adaptive vascular changes.

[0050] To further improve the targeting accuracy of shear stress simulation, this embodiment employs a partitioned design for the micro-protrusion array. The multiple micro-protrusions include a first group of micro-protrusions 510 and a second group of micro-protrusions 520.

[0051] The first set of micro-protrusions 510 is located in the central region of the inner surface of the sealed fluid sac 200, corresponding to the surface projection areas of the radial artery and cephalic vein in the forearm during use. In other words, when the trainer is correctly worn on the forearm, the first set of micro-protrusions 510 presses directly above the skin where the radial artery and cephalic vein run. The first set of micro-protrusions 510 has a relatively high height, ranging from 0.3 mm to 0.5 mm, and a relatively small spacing, ranging from 1 mm to 2 mm. The higher height and denser arrangement of the first set of micro-protrusions 510 result in stronger local pressure and greater shear strain on the skin in the vascular area.

[0052] The second group of microprotrusions 520 is arranged around the periphery of the first group of microprotrusions 510. The edge region corresponds to the non-vascular region of the forearm, such as the ulnar side and dorsal side. The second group of microprotrusions 520 has a lower height, ranging from 0.1 mm to 0.2 mm, and a larger spacing, ranging from 2 mm to 3 mm. The lower height and more sparse arrangement of the second group of microprotrusions 520 generate only mild background pressure on the non-vascular region, mainly for fixing the position of the bladder and preventing edge curling, without generating excessive shear stimulation.

[0053] Because vascular regions require stronger shear stress to promote endothelial cell activation, while non-vascular regions should avoid overstimulation to prevent tissue damage or discomfort, different microprotrusion parameters are used. Under the same hydrostatic pressure, higher, denser microprotrusions produce deeper local indentations and greater shear strain; while lower, sparser microprotrusions produce weaker stimulation. This zonal design achieves "targeted training"—concentrating the main energy in the vascular region while protecting surrounding tissues.

[0054] The zoned design avoids indiscriminate high-intensity compression across the entire area, improving training comfort and safety. Simultaneously, the increased shear stress in the vascular area significantly enhances training effectiveness. Furthermore, by adjusting the parameters (height, spacing, and arrangement direction) of the first group of micro-protrusions 510, personalized optimization can be performed for different patients based on their vascular depth and orientation.

[0055] To further improve patient comfort and safety, this embodiment provides a buffer layer between the inner wall of the columnar cavity of the support 100 and the outer surface of the sealed liquid bladder 200.

[0056] The buffer layer is a medical-grade sponge or silicone layer with a thickness of 2mm to 5mm. The buffer layer can be adhered to or embedded in the inner wall of the support base 100, or directly wrapped around the outer surface of the sealed liquid bladder 200. The buffer layer has a porous or elastic structure, capable of absorbing some vibration and impact. The buffer layer solves the stress mismatch problem between the rigid support base 100 and the flexible liquid bladder, resulting in a more uniform pressure distribution and avoiding discomfort or damage caused by excessive local pressure. The medical-grade sponge or silicone has good biocompatibility and breathability, and will not cause allergies with prolonged skin contact. Furthermore, the buffer layer can reduce noise and vibration generated by the trainer during operation, improving the user experience.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A preoperative vascular dilation training device for dialysis arteriovenous fistula surgery, characterized in that, include: The support base has a cylindrical cavity; A sealed liquid bladder is disposed in the cylindrical cavity of the support base. The sealed liquid bladder has an inner cavity, an inner surface, and an outer surface. The inner surface is used to fit against the skin surface of the forearm on the predetermined fistula side. An incompressible fluid is filled into the inner cavity of the sealed liquid bladder; A grip force driving assembly includes a grip ball and a transmission structure linked to the grip ball. The grip ball is disposed outside the sealed liquid sac and has a hollow inner cavity and an elastic outer wall. The transmission structure is connected to the fluid chamber of the sealed liquid sac. The grip force driving assembly is used to convert the patient's grip force into hydrostatic pressure in the fluid chamber. and A shear stress simulator is disposed on the inner surface of the sealed liquid bladder. The shear stress simulator is a micro-protrusion array structure. The shear stress simulator is used to convert the static pressure applied to the skin surface by the sealed liquid bladder into an alternating shear strain field of the subcutaneous tissue.

2. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 1, characterized in that: The sealed liquid bladder is a composite structure, including an outer layer, a receiving cavity, and an inner layer; the outer layer is a polyurethane fabric layer; the inner layer is a microstructure layer, the inner layer and the outer layer are arranged opposite to each other and surround the receiving cavity; the micro-protrusion array structure is integrally formed on the inner surface of the inner layer, the incompressible fluid fills the receiving cavity, and the receiving cavity is connected to the transmission structure.

3. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 1, characterized in that: The transmission structure includes a cylinder, a first elastic reset member, a first piston plate, a first piston rod, a hydraulic cylinder, a second elastic reset member, and a second piston plate; the first piston plate is sealed inside the cylinder and can move along the axial direction of the cylinder, the first piston plate divides the inner cavity of the cylinder into two non-communicating chambers, and the first elastic reset member is connected between the first piston plate and the inner wall of the cylinder; the end of the cylinder near the grip ball is connected to the hollow inner cavity of the grip ball through an air pipe; The second piston plate is sealed inside the cylinder and can move along the axial direction of the cylinder. The second piston plate divides the inner cavity of the cylinder into two non-communicating chambers. The second elastic reset member is connected between the second piston plate and the inner wall of the cylinder. The chamber of the cylinder near the sealed liquid bladder is connected to the inner cavity of the sealed liquid bladder through an oil pipe. The first piston rod is slidably connected between the first piston plate and the second piston plate.

4. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 3, characterized in that: It also includes a frequency acceleration mechanism; the first piston rod is connected to the second piston plate through the frequency acceleration mechanism; the frequency acceleration mechanism is used to convert the reciprocating motion of the first piston rod into a rapid reciprocating motion and deliver it to the second piston plate.

5. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 4, characterized in that: The frequency acceleration mechanism includes a second piston rod, a rack, a gear, and a driven disc; the rack is fixedly mounted on the first piston rod; the gear meshes with the rack; the driven disc is sleeved and fixed on the central shaft of the gear, and the outer circumferential surface of the driven disc is provided with multiple arc-shaped protrusions spaced circumferentially; one end of the second piston rod is connected to the second piston plate, and the other end of the second piston rod extends out of the cylinder and abuts against the outer circumferential surface of the driven disc; when the driven disc rotates, the arc-shaped protrusions push the second piston rod to perform linear reciprocating motion.

6. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 4, characterized in that: The end of the second piston rod is provided with a roller, which is in rolling connection with the arc-shaped protrusion.

7. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 1, characterized in that: The micro-protrusion array structure includes multiple micro-protrusions; the multiple micro-protrusions are distributed in an array along the inner surface of the sealed liquid bladder.

8. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 7, characterized in that: The plurality of micro-protrusions include a first group of micro-protrusions and a second group of micro-protrusions; the first group of micro-protrusions corresponds to the surface projection area of ​​the radial artery and cephalic vein in the human forearm; the second group of micro-protrusions is located in the edge area of ​​the inner surface of the sealed fluid sac and is arranged around the outer periphery of the first group of micro-protrusions; the height of the first group of micro-protrusions is 0.3 mm to 0.5 mm, and the spacing between the first group of micro-protrusions is 1 mm to 2 mm; the height of the second group of micro-protrusions is 0.1 mm to 0.2 mm, and the spacing between the second group of micro-protrusions is 2 mm to 3 mm.

9. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 1, characterized in that: The incompressible fluid is dimethyl silicone oil.

10. The vascular dilation training device for preoperative dialysis arteriovenous fistula surgery according to claim 1, characterized in that: A buffer layer is provided between the inner wall of the columnar cavity of the support and the outer surface of the sealed liquid bladder; the buffer layer is a medical-grade sponge layer or a silicone layer.

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