Multi-segment pressure navigation three-ball braided cerebral sinus plug taking stent and preparation method thereof

Abstract

This application provides a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent and its fabrication method, relating to the field of thrombectomy stent technology. The stent features an integrally formed mesh framework with an occlusion tennis ball, an embedded tennis ball, and a control tennis ball. The occlusion tennis ball forms a physical barrier in front of the thrombus generated within the target cerebral venous sinus to prevent its forward movement. The embedded tennis ball provides radial support to embed the thrombus and achieve anchoring. The control tennis ball is pulled to control the direction of the mesh framework. A Fabry-Perot fiber optic pressure sensor is integrated into the mesh framework to monitor the tip pressure in real time during thrombectomy. The stent improves the anatomical adaptability and apposition of the venous sinus, exhibiting excellent flexibility, mechanical safety, and biocompatibility. Furthermore, by adjusting the thrombectomy morphology through pressure sensing, it avoids excessive pressure damage to the vessel wall caused by the stent tip during thrombectomy, thus improving the safety of the surgical procedure.

Description

Technical Field

[0001] This application relates to the field of thrombectomy stent technology, and in particular to a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent and its preparation method. Background Technology

[0002] Cerebral venous sinus thrombosis (CVST) is a rare but potentially fatal cerebrovascular disease, accounting for approximately 0.5%-1% of all stroke cases. It is more common in young patients, especially women. The clinical manifestations of CVST are diverse and often nonspecific, leading to delayed diagnosis. Without timely treatment, it can cause increased intracranial pressure, cerebral edema, hemorrhage, seizures, coma, and even death. Currently, anticoagulation therapy is the first-line treatment for CVST, but approximately 10%-20% of patients experience continued deterioration after standard treatment, necessitating more effective interventions. Endovascular thrombectomy has become an important strategy for treating refractory CVST, with its core objective being to restore cerebral venous outflow, reduce intracranial pressure, and prevent further neurological damage. However, the anatomical structure of the cerebral venous sinus system is extremely complex. Common thrombotic sites include the superior sagittal sinus, transverse sinus, and sigmoid sinus. These sinuses are not only large in diameter and irregular in shape (such as triangular cross-sections), but also have tortuous and varied paths with many near-right-angle bends. These structural characteristics place extremely high demands on the flexibility, vascular fit, and operational stability of thrombectomy instruments.

[0003] Currently, the thrombectomy stents widely used in clinical practice were originally designed for the arterial system using laser cutting. Their application in venous sinuses has significant limitations: the anatomical structure and thrombus load of the stent are mismatched with the venous sinus, leading to difficult manipulation, high thrombus escape rates, and even potential damage to the vessel wall. Compared to traditional laser-cut stents, self-expanding braided stents offer superior structural flexibility, vascular fit, and reversible deformation capabilities, making them more suitable for the multi-bend, multi-segment, and variable-diameter pathways of the venous system.

[0004] In recent years, studies have proposed using tennis ball-shaped stents woven from nickel-titanium alloy wires. These stents, with their Z-shaped structure, enhance thrombus capture and vascular adaptability, demonstrating good performance in in vitro models and animal experiments. However, existing tennis ball-shaped structures lack sufficient regulatory capacity when dealing with larger thrombi and more complex vascular pathways, and also lack the ability to monitor the mechanical state in real time during thrombectomy. This results in serious shortcomings such as low thrombus capture efficiency, high risk of vascular injury, strong reliance on surgical experience, and poor controllability. Summary of the Invention

[0005] To address the aforementioned problems, one objective of this invention is to provide a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent, thereby solving the problems of poor wall apposition, limited functionality, easy thrombus migration and escape leading to low clearance efficiency, and high risk of vascular injury during operation associated with traditional thrombectomy devices. A second objective of this invention is to provide a method for preparing the multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent.

[0006] To achieve one of the objectives, in the first aspect, the present invention provides a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent, the technical solution of which is: A multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent, the stent comprising: The mesh skeleton is fabricated from shape memory alloy using three-dimensional weaving technology. From distal to proximal, the mesh skeleton is sequentially woven with occlusion tennis balls, embedding tennis balls, and control tennis balls. When the mesh skeleton is implanted into the target cerebral venous sinus, the occlusion tennis balls form a physical barrier in front of the thrombus generated within the target cerebral venous sinus to prevent its forward movement. The embedding tennis balls provide radial support to embed the thrombus and achieve anchoring. The control tennis balls are pulled to achieve directional control of the mesh skeleton. An optical fiber pressure sensor is mounted on the mesh skeleton to collect pressure signals from the mesh skeleton during the thrombectomy process.

[0007] As one preferred embodiment, the stent is used to connect to a control system, which includes a control handle and multiple microguidewires. One end of each microguidewire is connected to the control handle, and the other end is connected to each tennis ball in a corresponding manner. Each microguidewire is used to adjust the shape parameters of the corresponding tennis ball so that each tennis ball can be independently adapted to the anatomical structure of different segments of the target cerebral venous sinus.

[0008] As one preferred embodiment, the blocking tennis ball, the embedded tennis ball, and the control tennis ball together form a gradient functional zone; the gradient functional zone is composed of a breaking basket zone, a capture / breaking combination zone, and a capture basket zone; wherein... The broken basket area includes the blocking tennis ball, the embedded tennis ball, and the area between the two, and is used to break up adhesive thrombi. The capture / fragmentation combination zone includes the area where the embedded tennis ball is located, used to anchor the thrombus, and at the same time to perform secondary fragmentation on the thrombus after initial fragmentation by the fragmentation basket zone; The capture basket area includes a connection area between the control tennis ball and the embedded tennis ball, used to dynamically wrap the thrombus.

[0009] As one preferred embodiment, the connecting region is connected to the microguidewire so that the degree of closure of the connecting region can be adjusted by the microguidewire, thereby forming the dynamically shrinkable capture basket area.

[0010] As one of the preferred options, the net deployment area of ​​the blocking tennis ball, the embedded tennis ball, and the control tennis ball increases from small to large.

[0011] As one preferred embodiment, the blocking tennis ball, the embedded tennis ball, and the control tennis ball are arranged end-to-end, and adjacent tennis balls are naturally transitioned between each other through the mesh framework; and, The fiber optic pressure sensor is located at the far end of the mesh skeleton near the blocking tennis ball.

[0012] As one of the preferred embodiments, the shape memory alloy comprises nickel-titanium alloy wire, and the nickel-titanium alloy wire is heat-set after weaving to give the nickel-titanium alloy wire shape memory characteristics and low ion release characteristics.

[0013] To achieve the second objective, the present invention provides a method for preparing a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent, the technical solution of which is as follows: A method for preparing a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent, the method comprising: Nickel-titanium alloy wire is selected as the braiding material. Through three-dimensional braiding technology, a mesh skeleton with functions of blocking, embedding, and controlling tennis balls is formed in an integrated manner along the braiding direction. The mesh skeleton is heat-set to give it shape memory properties and low ion release properties. By integrating an optical fiber pressure sensor onto the mesh framework, a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent is obtained.

[0014] As one of the preferred solutions, the method also includes: Multiple microguidewires are connected to the occlusion tennis ball, the embedded tennis ball, and the control tennis ball respectively, and the microguidewires are connected to the control handle to complete the combination of the thrombectomy bracket and the control system.

[0015] As one preferred embodiment, the sensing head of the fiber optic pressure sensor is fixed to the far end of the mesh frame, and the transmission fiber of the fiber optic pressure sensor is extended along the mesh frame.

[0016] Compared with the prior art, this application has the following advantages: The stent provided in this application embodiment has a three-tendon structure that can expand in multiple coordinated segments. Combined with a wide range of adjustable aspect ratios, each tennis ball can independently adapt to the diameter and shape of the blood vessel segment it is located in, achieving dynamic compliant apposition to the vessel wall. It can stably expand in venous segments ranging from narrow to thick and in curved segments exceeding 120°, ensuring full contact with the blood vessel wall and laying the foundation for effective thrombectomy.

[0017] This application's embodiment relies on a three-tendon multi-segment synergistic structure (distal occlusion, mid-segment embedding, and proximal control) along with an internal dynamic capture-contraction structure (capture basket area) and a high-density fragmentation basket. Through a sequential "lock-slide-remove" operation, the proximal occlusion tennis ball physically blocks the thrombus from moving forward, the mid-segment embedding tennis ball stably embeds itself inside the thrombus, and the distal control tennis ball provides directional guidance. Combined with the "capture-contraction" structure at the connection interface of the proximal occlusion tennis ball, it can dynamically tighten and encapsulate the thrombus, forming multiple layers of protection. The internal high-density mesh further mechanically fragments adhesive chronic thrombi, thereby achieving efficient and complete removal of high-load, strongly adhesive thrombi. Simultaneously, it significantly improves the overall capture capability for long and complex-shaped thrombi, effectively reducing the risk of thrombus escape and distal migration, thus enhancing the stability and safety of the thrombectomy process.

[0018] This application integrates a fiber optic miniature pressure sensor based on the Fabry-Perot interference principle. Relying on the optical multi-beam interference principle, it can accurately calculate and provide real-time feedback on the pressure on the stent tip by monitoring the wavelength shift of the reflected interference spectrum caused by changes in the length of the Fabry-Perot cavity. This avoids excessive pressure damage to the blood vessel wall caused by the stent tip during thrombectomy, further improving the accuracy and safety of the surgical procedure.

[0019] The preparation method described above has the same advantages over existing technologies as the system described above, and will not be repeated here. Attached Figure Description

[0020] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the composition of a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent provided in one embodiment of this application; Figure 2This is a schematic diagram of the aspect ratio change of a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent provided in an embodiment of this application; wherein, 2(a) is a three-dimensional view of the stent in a preset configuration, and 2(b) is an adaptive configuration diagram after the preset configuration undergoes controllable deformation after adjusting the shape parameters of the stent; Figure 3 This is a combined graph of the diameter trend and aspect ratio trend of the multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent provided in an embodiment of this application at different lengths; wherein, the solid line represents the curve of length versus diameter, and the dashed line represents the curve of length versus aspect ratio; Figure 4 These are experimental photographs of the finished stent provided in Embodiment 1 of this application being inserted into a cerebral vein model for experimental testing; wherein, 4(a) on the left is the superior sagittal sinus of the cerebral vein model with the finished stent inserted, 4(b) in the middle is the sigmoid sinus of the cerebral vein model with the finished stent inserted, and 4(c) on the right is the transverse sinus of the cerebral vein model with the finished stent inserted. Figure 5 These are multi-condition displacement cloud diagrams of the finished bracket provided in Embodiment 1 of this application after finite element simulation analysis under different working conditions; wherein, 5(a) is the displacement cloud diagram of the finished bracket under axial tensile loading, 5(b) is the displacement cloud diagram of the finished bracket under axial torsional loading, 5(c) is the displacement cloud diagram of the finished bracket under unilateral compression loading, and 5(d) is the displacement cloud diagram of the finished bracket under three-point bending loading. Figure 6 These are multi-condition mechanical response curves of the finished bracket provided in Embodiment 1 of this application after displacement-stress testing under different working conditions; wherein, (1) is the stress-displacement relationship diagram of the finished bracket under axial torsional loading, (2) is the stress-displacement relationship diagram of the finished bracket under axial tensile loading, (3) is the stress-displacement relationship diagram of the finished bracket under left-side compression loading, and (4) is the stress-displacement relationship diagram of the finished bracket under three-point bending loading. Figure 7 This is a schematic diagram of the device used in the process of performing a flat plate compression test and a three-point bending test on the finished bracket provided in Embodiment 1 of this application; wherein, A is the flat plate compression test and B is the three-point bending test; Figure 8 This is a load-displacement curve diagram of the finished bracket provided in Embodiment 1 of this application during the flat plate compression test and the three-point bending test; wherein, the solid line represents the load-displacement curve during the flat plate compression test, and the dashed line represents the load-displacement curve during the three-point bending test; Figure 9 This is a structural assembly diagram of the finished bracket provided in Embodiment 2 of this application; wherein, the arrow represents the direction of optical signal transmission.

[0022] Explanation of reference numerals in the attached figures: 1. Nickel-titanium alloy wire; 11. Ball plugging device; 12. Ball embedding device; 13. Ball control device; 14. Fiber optic pressure sensor; 141. Single-mode fiber; 142. Capillary glass tube; 143. Pressure-sensitive diaphragm; 144. Interference cavity; 145. Transmission fiber; 2. Control handle; 3. Microguidewire; 4. Demodulation system. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Among existing cerebral venous sinus thrombectomy devices, the traditional tennis ball-shaped thrombectomy stent improves vascular fit to some extent by incorporating two spherical expansion segments and utilizing the self-expanding properties of the braided structure. However, in practical applications, this type of double-sphere structure still relies on a fixed geometry to achieve radial support and thrombus capture. When dealing with long, continuous thrombi, large-volume thrombi, complex tortuous paths, and structures with varying vessel diameters, it is prone to problems such as insecure anchoring, thrombus "plowing" forward, or escaping from the stent mesh. Furthermore, during the thrombectomy procedure, there is a lack of effective means to sense the contact state between the stent and the vessel wall and the mechanical forces acting on the stent, resulting in operational dependence on experience and insufficient safety and controllability.

[0025] The fiber optic pressure sensor 14, based on an optical signal transmission mechanism, features no risk of discharge and strong resistance to electromagnetic interference, making it particularly suitable for complex environments such as within blood vessels. Simultaneously, the fiber optic body is highly flexible and miniature, easily allowing for flexible integration and deployment along the device structure to achieve a pre-defined configuration. Furthermore, signal input and output can be achieved through a single optical path, which helps reduce system structural complexity and improve system stability. Therefore, this fiber optic pressure sensor 14 can achieve highly sensitive detection of minute pressure changes, providing an effective technical approach for acquiring the contact state between the stent and the vessel wall, as well as the mechanical changes during thrombectomy.

[0026] Based on the combination of the above-mentioned structural adaptability and mechanical sensing requirements, in order to meet the clinical needs of cerebral venous sinus thrombectomy devices for high adaptability and high reliability, it is urgent to develop a new type of braided thrombectomy stent with multi-segment adjustment capability, real-time sensing capability, gradient functional zoning, excellent mechanical compatibility and axial controllability, to improve the efficiency and safety of CVST thrombectomy.

[0027] Reference Figure 1 and Figure 9 As shown, this invention provides a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent. The stent includes: a mesh skeleton, which is formed by shape memory alloy through three-dimensional braiding technology; wherein, the mesh skeleton is sequentially braided from the distal end to the proximal end with occlusion tennis balls 11, embedding tennis balls 12, and control tennis balls 13, so that when the mesh skeleton is implanted into the target cerebral venous sinus, the occlusion tennis balls 11 are used to form a physical barrier in front of the thrombus generated in the target cerebral venous sinus to prevent the thrombus from moving forward, the embedding tennis balls 12 are used to provide radial support force to embed the thrombus and achieve anchoring, and the control tennis balls 13 are pulled to achieve directional control of the mesh skeleton; and an optical fiber pressure sensor 14 is set on the mesh skeleton to collect the pressure signal of the mesh skeleton during the thrombectomy process.

[0028] Specifically, the mesh framework serves as the main structure of the stent, preferably made of nickel-titanium alloy wire 1 with superelasticity and shape memory properties, integrally woven using a three-dimensional braiding process. The three-dimensional braiding process can employ a two-strand, four-strand, or multi-strand cross-weaving structure, with a braiding angle preferably around 30° to achieve a balance between radial support force and axial flexibility. The diameter of the shape memory alloy wire can be selected based on the size of the cerebral venous sinus vessels and the required radial force. A preferred example is the use of nickel-titanium alloy wire 1 with a diameter of 0.06 mm, woven using three-dimensional braiding technology at a braiding angle of 30°. The nickel-titanium alloy material possesses excellent superelasticity and biocompatibility; combined with the 30° braiding angle three-dimensional braiding structure, it endows the stent with extremely high flexibility and torsion, allowing it to adapt to the anatomical characteristics of the venous sinus, which is characterized by multiple bends, segments, and varying diameters. In some embodiments, the two ends of the stent are cylindrical connectors used to fix it to the delivery system and control system, ensuring a stable connection between the stent and the delivery system and preventing intraoperative dislodgement.

[0029] In a further preferred example of this embodiment, the nickel-titanium alloy wire 1 undergoes heat setting after three-dimensional braiding. By controlling the temperature, time, and cooling rate of the heat setting process, the mesh skeleton can self-expand and unfold after compression, adapting to the anatomical structure of the cerebral venous sinus. Specifically, the braided mesh skeleton can be placed in a pre-designed mold to maintain the geometric shape of the pre-designed three-sphere structure, and then heated in a protective atmosphere or vacuum environment, followed by cooling and setting. Through the above treatment, the nickel-titanium alloy wire 1 is in a pre-designed configuration before implantation into the blood vessel, constrained into a deployment configuration during implantation, and can automatically return to the pre-designed configuration in the released state after implantation, giving it good shape memory characteristics and superelasticity. In some cases, such as Figure 2As shown, the initial preset configuration of the mesh framework can be adjusted by manipulating the microguidewire 3, allowing for controllable deformation of the preset configuration to adapt to cerebral venous sinus segments of different diameters and shapes. Furthermore, the nickel-titanium alloy wire 1, after heat treatment, also possesses low ion release characteristics, and the entire scaffold exhibits no significant cytotoxicity, meeting the biocompatibility requirements for intracranial implantation. Through the above material selection and processing methods, the mesh framework not only possesses excellent shape recovery ability and flexibility but also low ion release characteristics, meeting the dual requirements of mechanical performance and biosafety for cerebral venous sinus thrombectomy.

[0030] The improvement in this embodiment lies in the fact that the mesh skeleton has three mesh units distributed in series along the axial direction. By controlling the weaving density and weaving angle, the mesh can be designed into rhomboid, hexagonal, or other regular or irregular polygonal structures to achieve a balance between blood flow permeability and thrombus capture capability. Specifically, the three mesh units can be a clogging tennis ball 11, an embedded tennis ball 12, and a control tennis ball 13 arranged sequentially from the distal end to the proximal end. The three tennis balls are a continuous structure and are connected by transition weaving sections. Two transition weaving sections connect the clogging tennis ball 11, the embedded tennis ball 12, and the control tennis ball 13 through a gradient structure along the axial direction, so that adjacent tennis balls can transition naturally through the weaving skeleton. Therefore, the three tennis balls are formed sequentially along the weaving direction without additional connecting parts to ensure the continuity and flexibility of the mesh skeleton. The axial length and weaving density of the two transition weaving sections can be set according to different functional requirements. Their lengths can be the same or different, and their weaving densities can also be the same or different, thereby forming specific gradient functional zones and mechanical property distributions.

[0031] By selecting different transition braiding designs, the three-tendon structure can form various spacing patterns. For example, in one embodiment, the occlusion tennis ball 11, the embedding tennis ball 12, and the control tennis ball 13 are arranged at equal intervals along the axial direction, and the lengths of each transition braiding segment are basically the same. In another embodiment, the transition braiding segment between the occlusion tennis ball 11 and the embedding tennis ball 12 is shorter and has a higher braiding density, while the transition braiding segment between the embedding tennis ball 12 and the control tennis ball 13 is longer and has a lower braiding density. In a preferred embodiment, the transition braiding segment between the occlusion tennis ball 11 and the embedding tennis ball 12 is longer, while the transition braiding segment between the embedding tennis ball 12 and the control tennis ball 13 is shorter, but the braiding density of the two transition braiding segments is basically the same. The two transition braiding segments and the three tennis balls together form gradient functional zones on the mesh framework. The gradient functional zones include a fragmentation basket area for breaking up adherent thrombi, a capture / fragmentation combination area that combines thrombus anchoring and secondary fragmentation functions, and a capture basket area where the degree of closure is adjusted by the microguidewire 3 to wrap the thrombus. The stent's internal design integrates gradient functional zones, enabling the three-tendon structure to not only achieve multi-segment synergistic effects of occlusion, embedment, and control, but also for the synergistic effect of each functional zone to form a sequential thrombectomy pattern of "lock-slide-removal," significantly improving thrombus capture and clearance efficiency. Further details regarding this specific feature will be provided later.

[0032] Following the previous section, three tennis balls are arranged sequentially from the distal to the proximal end of the mesh framework, with adjacent balls naturally transitioning through the woven framework. Taking the direction of use as an example, the proximal end is the direction closer to the operator, and the distal end is the direction opposite to the proximal end. The occlusion tennis ball 11 is located at the distal end of the mesh framework. Its outer diameter, in the released state, is slightly larger than or approximately equal to the inner diameter of the corresponding segment of the target cerebral venous sinus. After stent deployment, the occlusion tennis ball 11 adheres to the inner wall of the blood vessel due to the shape memory properties of the nickel-titanium alloy material, forming a physical barrier in front of the thrombus to prevent its forward / distal migration. The embedding tennis ball 12 is located between the occlusion tennis ball 11 and the control tennis ball 13. Its outer diameter can be basically matched with or slightly larger than the inner diameter of the corresponding segment of the blood vessel. After stent deployment, the embedding tennis ball 12 uses the supporting force generated by radial expansion to press the thrombus into the mesh structure, thereby achieving mechanical embedding and anchoring of the thrombus and improving the overall thrombus capture capability. The control tennis ball 13 is located at the proximal end of the mesh frame, and its structure can be used to connect with a conveying system or control system to achieve directional control and synchronous traction of the support.

[0033] The weaving density, mesh shape and size, and mesh structure of the blocking tennis ball 11, the embedded tennis ball 12, and the control tennis ball 13 can be the same or different. The distal end face of the three tennis balls is woven into a relatively closed mesh structure, or a semi-closed end cap structure is formed by increasing the local weaving density, so as to further achieve the blocking, embedding, and guiding effects of each tennis ball.

[0034] In a specific implementation, the blocking tennis ball 11, the embedded tennis ball 12, and the control tennis ball 13 are arranged end to end along the axial direction of the mesh skeleton, that is, each tennis ball is arranged continuously with a short distance between them. Adjacent tennis balls are connected by a short transition weaving section to form an integrated structure, so that the three tennis balls form a continuous action area along the vascular axis after being unfolded, thereby avoiding large discontinuities or gaps between the formed gradient functional zones, which is conducive to achieving continuous coverage treatment of thrombi.

[0035] Another improvement in this embodiment is that the fiber optic pressure sensor 14 is disposed on the mesh skeleton, preferably at the distal end near the occlusion tennis ball 11, to obtain pressure information between the stent tip and the blood vessel wall. The fiber optic pressure sensor 14 can be constructed using a fiber optic grating-based interferometric fiber optic sensing principle, which characterizes changes in external pressure through changes in optical signals. Optionally, the fiber optic pressure sensor 14 includes a sensing head, a transmission fiber 145, and a demodulation system 4; the sensing head includes a single-mode fiber 141, a capillary glass tube 142, and a pressure-sensitive diaphragm 143. The single-mode fiber 141 is fixed to one end of the capillary glass tube 142, and the pressure-sensitive diaphragm 143 is fixed to the other end of the capillary glass tube 142 and parallel to the end face of the capillary glass tube 142. The end face of the single-mode fiber 141 and the inner surface of the pressure-sensitive diaphragm 143 form a closed Fabry-Perot interferometer cavity 144; the transmission fiber 145 of the fiber optic pressure sensor 14 can extend along the braiding path of the mesh skeleton and be attached to the surface of the nickel-titanium alloy wire 1. The transmission fiber optic cable 145 is connected to the sensing head to transmit changes in optical signals. In use, the end of the transmission fiber optic cable 145 furthest from the sensing head is connected to the demodulation system 4. The demodulation system 4 emits incident light and receives reflected interference light signals to calculate pressure values. Therefore, when the stent contacts the blood vessel wall and generates pressure changes, this pressure is transmitted through the skeleton structure to the fiber optic pressure sensor 14, causing changes in the optical properties of the fiber optic pressure sensor 14. This allows for real-time acquisition and analysis of the pressure signal through an external optical signal demodulation device, providing mechanical feedback information for thrombectomy operations.

[0036] In summary, this application has the following significant advantages compared with the prior art: Compared to existing arterial stents (such as laser-cut stents) which have high rigidity but struggle to adapt to the diameter variations of venous sinuses (narrower at the front and wider at the back) and irregular shapes such as triangular cross-sections, leading to poor apposition or vascular damage, the three-tendon structure of this invention can perform multi-segment coordinated expansion. Combined with a wide range of adjustable aspect ratios (6.7–27.6), each tendon can independently adapt to the diameter and shape of its respective vascular segment, achieving dynamic compliant apposition. It can stably expand in venous segments ranging from narrow to thick and in bends exceeding 120°, ensuring sufficient contact with the vascular wall and laying the foundation for effective thrombectomy.

[0037] Compared to traditional single-segment or double-tendon stents, which are prone to problems such as insecure anchoring, thrombus "plowing" forward, or escape from the stent mesh during thrombectomy, this invention utilizes a three-tendon multi-segment synergistic structure (distal occlusion, mid-segment embedding, and proximal control) along with an internal dynamic capture-contraction structure (capture basket area) and a high-density fragmentation basket. Through a sequential "lock-slide-remove" operation, the distal occlusion tennis ball 11 physically blocks thrombus movement, the mid-segment embedding tennis ball 12 stably embeds itself within the thrombus, and the "capture-contraction" structure between the occlusion tennis ball 11 and the embedding tennis ball 12 tightens and encapsulates the thrombus, forming multiple layers of protection. The distal control tennis ball 13 provides directional traction and control, and the internal high-density mesh further mechanically fragments adhesive chronic thrombi, thereby achieving efficient and complete removal of high-load, strongly adhesive thrombi. Simultaneously, it significantly improves the overall capture capability for long and complex-shaped thrombi, effectively reducing the risk of thrombus escape and distal migration, thus enhancing the stability and safety of the thrombectomy process.

[0038] Compared to existing stents, which are prone to resistance, jamming, and even vascular perforation when navigating multiple right-angle bends in the venous sinuses (such as the superior sagittal-transverse sinus junction and bends within the sigmoid sinus), this invention features an integrated flexible skeleton based on a three-dimensional braided nickel-titanium alloy wire, along with a control system capable of axial extension, contraction, and rotation. The integrated braided structure and shape memory alloy material endow the stent with excellent flexibility. Mechanical simulations and experiments have demonstrated that the stent exhibits low stiffness (three-point bending reaction force of only 0.008N) and high compliance under bending, torsion, and compression. Combined with its axial controllability, the operator can precisely guide the stent through tortuous paths, significantly improving navigation success rates and minimizing the risk of damage to the venous sinus intima.

[0039] This invention integrates a fiber optic pressure sensor 14 based on the Fabry-Perot interference principle. The fiber optic pressure sensor 14 consists of a sensing head, a transmission fiber 145, and a demodulation system 4. Relying on the optical multi-beam interference principle, it can accurately calculate the pressure on the stent tip and provide real-time feedback by monitoring the wavelength drift of the reflection interference spectrum caused by the change in the length of the Fabry-Perot cavity. This avoids excessive pressure damage to the blood vessel wall caused by the stent tip during thrombectomy, and further improves the accuracy and safety of the surgical operation.

[0040] Furthermore, the stent exhibits good biocompatibility and manufacturing feasibility, facilitating clinical translation. By employing a biocompatible nickel-titanium alloy material and integrating it through three-dimensional braiding and heat treatment, in vitro biocompatibility assessments showed that the treated nickel-titanium alloy wire 1 exhibited low nickel ion release and no significant cytotoxicity, meeting the biosafety requirements for implantable medical devices. Simultaneously, three-dimensional braiding technology, as a mature textile process, easily enables the one-time molding of complex structures (such as three tennis balls), demonstrating good process repeatability and large-scale production potential, thus ensuring stable product quality and successful clinical application.

[0041] As a further explanation of this embodiment, based on the aforementioned principles and advantages, increasing the number of mesh units does not necessarily lead to improved clinical efficacy. On the contrary, under human vascular anatomy conditions, excessive spherical segments can significantly alter the overall mechanical properties of the mesh framework. In previous in vitro simulations and human model experiments, the applicant discovered that as the number of spherical mesh units increases, the overall flexibility of the stent decreases, its axial bending adaptability weakens, and it is more prone to local stress concentration when traversing the complex tortuous path of the cerebral venous sinus, even leading to excessive local stress on the woven structure, resulting in deformation inconsistencies or breakage risks. For example, if a four-spherical segmented structure is further adopted, although more multi-segment collaboration is achieved, the corresponding increase in transition woven segments between adjacent spherical segments leads to enhanced discontinuity in the overall structural stiffness distribution. This makes the stent more prone to jamming, uneven folding, or superimposed stress during push-out, deployment, and retrieval, thereby amplifying the aforementioned problems of insufficient flexibility and structural failure. Therefore, this implementation method takes into account vascular adaptability, mechanical properties and thrombectomy effect, and proposes a targeted optimization scheme of three tennis balls connected in series. It specifically combines the three functional segments of occlusion, embedding and control, and establishes gradient functional zoning. Under the premise of ensuring the overall flexibility and structural reliability of the stent, it realizes the multi-segment synergistic effect of thrombus blocking, anchoring and traction control.

[0042] This application further illustrates the gradient functional zoning. The occlusion tennis ball 11, the embedded tennis ball 12, and the control tennis ball 13 together form a gradient functional zoning; the gradient functional zoning is composed of a fragmentation basket area, a capture / fragmentation combination area, and a capture basket area; wherein, the fragmentation basket area includes the occlusion tennis ball 11, the embedded tennis ball 12, and the area between them, used to fragment adherent thrombi; the capture / fragmentation combination area includes the area where the embedded tennis ball 12 is located, used to anchor thrombi, and simultaneously perform secondary fragmentation on thrombi initially fragmented by the fragmentation basket area; the capture basket area includes the connection area between the control tennis ball 13 and the embedded tennis ball 12, used to dynamically encapsulate thrombi.

[0043] In this embodiment of the invention, to achieve efficient thrombus treatment, the stent is designed with integrated gradient functional zones. These zones work together to form a sequential thrombectomy pattern of "lock-slide-removal," significantly improving the efficiency of thrombus capture and removal, as detailed below: The broken net basket area: This area is located in the areas of the blocking net 11 and the embedded net 12, as well as the transition braided section between them, and integrates a high-density braided mesh. The structural design of the high-density braided mesh enables it to effectively cut and mechanically break up tightly adhered chronic white thrombi, breaking the strong adhesive properties of chronic thrombi and creating conditions for subsequent thrombus capture and removal.

[0044] Capture / Fragmentation Combination Zone: Located in the area where the embedded tennis ball 12 is situated, this zone combines anchoring and secondary fragmentation functions. While the embedded tennis ball 12 achieves stable anchoring by embedding into the thrombus, this zone can perform secondary fragmentation on the thrombus that has been initially fragmented by the fragmentation basket zone, further reducing the thrombus volume and lowering the probability of thrombus escape.

[0045] Capture basket area: This area is located between the transition braided section between the control tennis ball 13 and the embedded tennis ball 12, and between the end faces of the two tennis balls. Specifically, it is the interface area formed by the control tennis ball 13 and the embedded tennis ball 12. By manipulating the microguidewire 3 connected to it, the degree of closure of this area / space can be adjusted, shortening the distance between the control tennis ball 13 and the embedded tennis ball 12, forming a dynamic "capture-contraction" structure. When a thrombus is pulled into this interface area, the area can tighten and firmly encapsulate the thrombus, for example, gathering up secondary fragmented thrombi as a whole, and sealing the distal blocking interface with the blocking tennis ball 11. This significantly enhances the embedding strength of the thrombus and the overall clearance efficiency, while effectively preventing the thrombus from escaping from the stent mesh during retraction.

[0046] Therefore, based on the multi-segmented collaborative division of labor formed by the occlusion tennis ball 11, the embedding tennis ball 12, and the control tennis ball 13, a gradient functional zoning is further formed, with gradient spacing and coordinated operation. By integrating different functional areas onto three tennis ball segments and achieving linkage through the control handle 2, the limitations of traditional single-tool thrombectomy devices are overcome, transforming the integrated device into a multi-functional workstation capable of dynamically adjusting its strategy according to the nature (e.g., fresh vs. chronic) and location of the thrombus. Utilizing a high-density mesh for fragmentation or a capture-contraction structure for complete removal, the gradient distribution of functions and the synergy of segmented operations enable physicians to adopt optimal, targeted treatment strategies for specific clinical scenarios, greatly improving treatment efficiency and success rate.

[0047] In this embodiment, please refer again. Figure 9 and Figure 2The stent is connected to the control system, which independently adjusts each tennis ball structure on the mesh framework to achieve multi-segment adaptive deployment and morphological control. The control system includes a control handle 2 and multiple microguidewires 3, preferably three, corresponding to the occlusion tennis ball 11, the embedded tennis ball 12, and the control tennis ball 13, respectively. One end of each microguidewire 3 is connected to the control handle 2, and the other end is connected to the corresponding tennis ball structure, thus forming a one-to-one independent control channel. By operating the control handle 2, the stent can be compressed or released, dynamically adjusting the total length of the stent within a preset range to adapt to cerebral venous sinus segments of different diameters and shapes. The distal end of the microguidewire 3 is fixedly connected to the distal end of each tennis ball on the framework, allowing each tennis ball to achieve independent radial size adjustment, morphological adjustment, and support force control, enabling the stent to be segmentally adapted according to the diameter changes and curvature of different vascular segments of the target cerebral venous sinus. During thrombectomy, the operator can dynamically adjust each tennis ball based on real-time imaging information and pressure feedback information, thereby achieving precise operation on complex vascular structures and different types of thrombi.

[0048] The control handle 2 is connected to three tennis ball functional segments of different mesh sizes via three independent microguidewires 3. By operating the control handle 2, the stent can be compressed or released, allowing the total length of the stent to be dynamically adjusted between 50mm and 66mm. The corresponding aspect ratio can vary within a wide range from 6.7 to 27.6, thus adapting to venous sinus segments of different diameters and shapes, solving the problem of mismatch between existing stents and the anatomical structure of venous sinuses. As the stent length increases, its diameter increases non-linearly, while the aspect ratio gradually decreases. Within the 56-62mm range, the stent simultaneously possesses a moderate diameter and a reasonable aspect ratio (approximately 4-5), achieving an optimal balance between axial support and radial wall adhesion. This length can be selected as the preferred structural design range (e.g., ...). Figure 3 (As shown).

[0049] In this embodiment, the control handle 2 can take the form of various clinically common interventional device operation control handles to achieve independent or coordinated control of multiple microguidewires 3. The specific form can be selected according to operating habits, control precision requirements, and structural integration needs; this embodiment will not elaborate further on these details.

[0050] In conjunction with the above embodiments, the capture basket area includes a transition braided section between the control tennis ball 13 and the embedded tennis ball 12. This transition braided section is connected to a microguide wire 3, allowing the microguide wire 3 to adjust the degree of closure of the interface area, thereby forming a dynamically shrinkable capture basket area. In this embodiment, by applying axial traction or release to the microguide wire 3, the degree of contraction of the transition braided section can be adjusted, causing the area to dynamically change between an expanded state and a tightened state, thereby forming a capture-contraction structure with dynamically adjustable opening size. Specifically, the transition braided section between the embedded tennis ball 12 and the control tennis ball 13 has a longer axial length than the transition braided section between the blocking tennis ball 11 and the embedded tennis ball 12. When the microguide wire 3 acts on this longer transition braided section, its axial displacement can be converted into a more significant deformation and contraction effect, thereby forming an effective wrapping and tightening structure without disrupting the overall mechanical continuity of the three-tennis structure.

[0051] During use, under image guidance, the stent is compressed and housed in the distal lumen of the delivery microcatheter. The mesh framework, under compression, converges axially, and each tennis ball structure is constrained into a deployment configuration. Subsequently, the delivery microcatheter is advanced along the vascular pathway to the target venous sinus (such as the superior sagittal sinus, transverse sinus, or sigmoid sinus), locating the distal end of the microcatheter distal to the thrombus. After positioning, the operator gradually withdraws the delivery microcatheter, releasing the mesh framework sequentially from distal to proximal. During release, the nickel-titanium alloy wire 1, freed from constraint, self-expands and returns to its preset configuration, and the stent gradually unfolds and conforms to the vessel wall. After the microcatheter is withdrawn, the operator uses the control handle 2 to adjust the axial position and tension of each microguidewire 3, finely adjusting the local length of the stent and the radial dimensions of each tennis ball. This ensures that the occlusion tennis ball 11, the embedded tennis ball 12, and the control tennis ball 13 are matched to different segments of the vessel, achieving gradient wall adhesion and segmental adaptation, providing a stable foundation for thrombectomy. For example, the expansion degree of the occlusion tennis ball 11 can be appropriately adjusted to enhance the distal blocking effect, the radial support force of the embedded tennis ball 12 can be enhanced to improve the thrombus embedding and anchoring ability, and the overall axial force and directional control can be optimized by controlling the shape adjustment of the tennis ball 13. Then, the thrombectomy stage begins. The three tennis balls work together in a multi-segment synergistic manner, combined with the functional zoning effect. The occlusion tennis ball 11 forms a physical barrier in front of the thrombus, preventing the thrombus from moving forward. The embedded tennis ball 12 embeds itself inside the thrombus, achieving anchoring and secondary fragmentation through the capture / fracture combination zone. The microguidewire 3 is controlled to dynamically adjust the proximal region of the occlusion tennis ball 11 to tighten and wrap the thrombus. Then, the traction and retraction of the control tennis ball 13 finally pulls the entire thrombus out to the retrieval catheter, completing the thrombectomy operation.

[0052] During the aforementioned adjustment and thrombectomy process, the fiber optic pressure sensor 14 synchronously collects the pressure signal between the stent and the vessel wall. The operator can dynamically correct the mesh skeleton based on the feedback information to avoid excessive local pressure leading to vessel damage or insufficient pressure leading to inadequate adhesion to the vessel wall. This ensures that the stent and the vessel wall form a stable and uniform contact state, providing a reliable basis for the thrombectomy operation.

[0053] In a preferred embodiment, the mesh-like unfolded areas of the occlusion tennis ball 11, the embedded tennis ball 12, and the control tennis ball 13 in their unfolded state increase progressively along the axial direction. That is, the mesh-like unfolded area of ​​the occlusion tennis ball 11 is the smallest, followed by the embedded tennis ball 12, and the control tennis ball 13 is the largest. The mesh-like unfolded area can be understood as the projected area or envelope area of ​​the outer contour of each tennis ball in its freely unfolded state. For example, the axial lengths of the occlusion tennis ball 11, the embedded tennis ball 12, and the control tennis ball 13 can be the same, but their mesh diameters can be different; conversely, their axial lengths can be different, but their mesh diameters can be the same; or both their axial lengths and mesh diameters can be different. Through this gradient size design, the stent achieves a progressively enhanced encapsulation capacity from distal to proximal during thrombosis treatment, while avoiding stress concentration caused by excessive expansion of local structures. This helps improve overall mechanical stability and reduce the risk of fracture.

[0054] In one design configuration, the occlusion tennis ball 11, as a distal functional unit, measures 6 mm in diameter and 13.15 mm in length. Its main function is to form a physical barrier in front of the thrombus, effectively preventing the thrombus from migrating forward during the procedure and avoiding the risk of new vascular occlusion caused by thrombus displacement. The embedded tennis ball 12, as an intermediate functional unit, measures 8.65 mm in diameter and 13.15 mm in length. Its core function is to provide stable radial support, embedding itself within the thrombus for effective anchoring, providing stable support for subsequent thrombus fragmentation and capture, and preventing stent slippage during thrombectomy. The control tennis ball 13, as a proximal functional unit, measures 8.65 mm in diameter and 17.65 mm in length. This occlusion tennis ball 11 is connected to the control microguidewire 3 and is mainly responsible for the directional control and synchronous traction of the stent, facilitating precise adjustment of the stent's position and orientation within the venous sinus by the operator.

[0055] Correspondingly, in a second aspect, the present invention also provides a method for preparing a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent, used to prepare the multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent provided in the first aspect of the present invention. The method includes the following steps: S1. Nickel-titanium alloy wire 1 is selected as the braiding material. Through three-dimensional braiding technology, a mesh skeleton with blocking tennis balls 11, embedded tennis balls 12 and controlling tennis balls 13 is formed in an integrated manner along the braiding direction.

[0056] S2. The mesh skeleton is heat-set. By controlling the temperature, time and cooling rate of the heat-setting process, the mesh skeleton can be endowed with shape memory properties and low ion release properties.

[0057] S3. Select fiber optic pressure sensor 14, fix the sensing head of fiber optic pressure sensor 14 to the far end of the mesh skeleton, and extend the transmission fiber 145 of fiber optic pressure sensor 14 along the mesh skeleton to obtain a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent.

[0058] S4. Connect the multiple microguidewires 3 to the blocking tennis ball 11, the embedded tennis ball 12 and the control tennis ball 13 respectively, and connect the microguidewires 3 to the control handle 2 to complete the combination of the thrombectomy bracket and the control system.

[0059] It should be noted that, for the method embodiments, the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps may be performed in other orders or simultaneously.

[0060] The above method embodiments are basically similar to the stent embodiments, so the description is relatively simple. For relevant details, please refer to the description of the stent embodiments.

[0061] Example 1: A method for preparing a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent includes the following steps: Material preparation: Select nickel-titanium alloy wire 1 with a diameter of 0.06mm. This nickel-titanium alloy wire 1 must meet the requirements of biocompatibility and superelasticity to lay the foundation for the biosafety and mechanical properties of the subsequent stent.

[0062] Three-dimensional braiding: Using a three-dimensional braiding device, nickel-titanium alloy wire 1 is braided into a flexible mesh skeleton with three tennis balls connected in series at a braiding angle of 30°. After braiding, the size of tennis ball 13 is controlled to be 8.65mm in diameter and 17.65mm in length, the size of embedded tennis ball 12 is 8.65mm in diameter and 13.15mm in length, and the size of sealing tennis ball 11 is 6mm in diameter and 13.15mm in length. The three tennis balls are naturally transitioned between each other through the braided skeleton without any additional connecting parts, ensuring the continuity and flexibility of the structure.

[0063] Heat setting treatment: The woven mesh skeleton is subjected to precise heat setting treatment. By controlling the heat treatment temperature, time and cooling rate, the hyperelastic shape and recovery performance of the stent are set to ensure that the stent can self-expand and unfold after compression, and the unfolded shape is adapted to the anatomical structure of the venous sinus.

[0064] Connector processing: The two ends of the stent are processed to form cylindrical connectors, which are used to fix the stent to the delivery system and control components, ensuring a stable connection between the stent and the delivery system, and finally obtaining a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent.

[0065] Example 2: To achieve the pressure navigation function of the bracket, after the connecting part is processed, a fiber optic pressure sensor 14 based on the Fabry-Perot interferometry principle is integrated into the tip of the bracket. This sensor is connected to the demodulation system 4 at the back end via a transmission fiber optic cable 145, thus completing the integration of the pressure navigation function. Specifically: A method for fabricating a multi-segment pressure-guided three-sphere braided cerebral venous sinus thrombectomy stent includes material preparation, three-dimensional braiding molding, heat setting treatment, and integration of a fiber optic pressure sensor 14. The material preparation, three-dimensional braiding molding, and heat setting treatment are the same as in Example 1. In the fiber optic pressure sensor 14 integration step: 2.1 Overall structure of fiber optic pressure sensor 14; like Figure 1 and Figure 9 As shown, the fiber optic pressure sensor 14 mainly consists of three parts: a sensing head, a transmission fiber 145, and a demodulation system 4. The sensing head mainly consists of a single-mode fiber 141, a capillary glass tube 142, and a pressure-sensitive diaphragm 143. The specific structure is as follows: a single-mode optical fiber 141 with its end face cleaned and flattened is fixed to one end of a capillary glass tube 142 with an inner diameter slightly larger than the outer diameter of the optical fiber; a circular thin sheet made of silicon or stainless steel serves as a pressure-sensitive diaphragm 143, which is bonded to the other end of the capillary glass tube 142 by high-temperature fusion or special epoxy adhesive, and is strictly parallel to the end face of the capillary glass tube 142; a sealed micro air gap filled with a low expansion coefficient gas (such as nitrogen) or a vacuum is formed between the end face of the single-mode optical fiber 141 and the inner surface of the pressure-sensitive diaphragm 143, which constitutes the core sensing element - the interference cavity 144 (abbreviated as Fabry-Perot cavity, FP cavity). The end face of the optical fiber and the inner surface of the diaphragm serve as two parallel reflecting surfaces, and the distance between them is the initial cavity length L0 of the Fabry-Perot cavity.

[0066] Transmission fiber 145: The sensing head is connected to the demodulation system 4 at the back end via a standard single-mode communication fiber (up to several kilometers long). This transmission fiber 145 is responsible for transmitting the incident light from the demodulation system 4 to the sensing head and transmitting the reflected interference light signal containing cavity length information back to the demodulation system 4, realizing bidirectional transmission of optical signals. Moreover, because the fiber optic pressure sensor 14 has a compact overall structure, it will not affect the flexibility of the support or the operational flexibility.

[0067] Demodulation System 4: Demodulation System 4 includes a broadband light source, an optical fiber circulator, and a spectrometer. The output of the broadband light source is connected to the input (first port) of the optical fiber circulator; the output (second port) of the optical fiber circulator is connected to the sensor head via transmission fiber 145; and the return (third port) of the optical fiber circulator is connected to the spectrometer. Demodulation System 4 enables the transmission, reception, and analysis of optical signals, providing data support for pressure calculations.

[0068] 2.2 Working principle of fiber optic pressure sensor 14: The fiber optic pressure sensor 14 in this embodiment achieves pressure detection based on the principle of optical multi-beam interference. The specific principle is as follows: Light emitted from a broadband light source is transmitted to the sensing head through a fiber optic circulator; when the light reaches the fiber end face (the first reflecting surface, with a reflectivity of approximately R1=4%), part of the light is reflected back to the transmission fiber 145, and the other part of the light is transmitted into the Fabry-Perot cavity; when the transmitted light reaches the inner surface of the pressure-sensitive diaphragm 143 (the second reflecting surface, with a reflectivity R2 that can be adjusted by coating), it is partially reflected again; when these two reflected beams meet in the transmission fiber 145, they interfere due to their optical path difference (2nL, where n is the refractive index of the cavity medium and L is the instantaneous cavity length), forming a bright and dark reflection interference spectrum that varies with wavelength. The interference maxima (peaks) or minima (troughs) satisfy the condition: 2nL=mλ (where m is the interference order and λ is the wavelength).

[0069] When external pressure P is applied to the pressure-sensitive diaphragm 143, the diaphragm undergoes a slight elastic bending deformation, causing the cavity length L of the Fabry-Perot cavity to decrease from the initial value L0 to L0-ΔL. The change in cavity length L directly alters the optical path difference between the two reflected beams, resulting in a phase shift in the reflected interference spectrum, manifested as a wavelength shift Δλ in the interference spectrum. By accurately measuring the wavelength shift Δλ using a spectral analyzer, the change in cavity length ΔL can be calculated based on the calibration relationship. Then, using the mechanical model of the diaphragm (ΔP=k×ΔL, where k is the diaphragm stiffness coefficient), the precise pressure value ΔP can be obtained, enabling real-time pressure detection.

[0070] 2.3 Working process of fiber optic pressure sensor 14: Under no-pressure (P=0) conditions, demodulation system 4 records the initial reflected interference spectrum (reference spectrum) of the sensor head and determines the wavelength λ0 of a certain characteristic valley. The sensor head is placed in the pressure environment to be measured (i.e., the area where the stent tip contacts the blood vessel wall or thrombus). Pressure P acts on the pressure-sensitive diaphragm 143, causing it to bend towards the end face of the single-mode fiber 141, reducing the cavity length by ΔL. At this time, the reflected interference spectrum shifts relative to the reference spectrum. The spectrometer monitors and captures the wavelength shift of the characteristic valley to λ1 in real time. The processing unit of demodulation system 4 calculates the wavelength shift according to the formula Δλ=λ1-λ0. The on-site pressure value is directly calculated using the sensor sensitivity coefficient S (unit: nm / kPa, determined by calibration experiments) pre-stored in the system: P=(Δλ) / S. Finally, the pressure value is displayed in real time or transmitted to the host computer to provide pressure navigation feedback for the operator and avoid excessive pressure damage to the blood vessel wall caused by the stent tip.

[0071] To verify the structural rationality and thrombectomy performance of the multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent provided in this application, the finished stent provided in Example 1 was subjected to mechanical performance tests, experimental tests, and biocompatibility tests, respectively, to verify that the provided stent structure meets the design requirements and its performance meets the standards, thus providing a guarantee for the stable quality of the product and its clinical application.

[0072] (a) Mechanical performance testing: To verify the reliability of the stent provided by this invention in complex vascular environments, the mechanical behavior of the stent was systematically evaluated through finite element simulation and in vitro experiments to ensure that the stent has sufficient mechanical safety margin and avoids intraoperative structural failure.

[0073] 1. Finite element simulation analysis; The ABAQUS software was used to simulate four load conditions on the support model (containing 41,832 secondary beam elements and 622,105 tetrahedral elements). The overall deformation characteristics under four typical loading conditions—axial torsion, axial tension, unilateral compression, and three-point bending—were tested. The material parameters of the nickel-titanium alloy wire 1 were set as follows: Young's modulus 67 GPa, Poisson's ratio 0.3, etc. Figure 5 and Figure 6 As shown, the specific simulation results are as follows: Axial tension condition: Figure 5 Figure 5(a) shows the displacement contour plot corresponding to the axial tensile test, which shows the overall elongation and stress concentration at the connection from the middle to the distal end of the airbag. Figure 6Figure (2) shows the stress-displacement curves of the proximal, middle, and distal airbags under axial tensile testing. An axial displacement of 8 mm was applied to the stent. Simulation results showed that the maximum von Mises stress was 80.2 MPa, occurring at the connection between the embedded tennis ball 12 and the sealing tennis ball 11; the maximum principal strain was 0.0048, and the maximum displacement was 7.68 mm. The stent exhibited uniform overall deformation without local instability, indicating that the stent was structurally stable under axial tensile load and could withstand the axial traction force during thrombectomy.

[0074] Single-sided compression condition: Figure 5 Figure 5(c) shows the displacement contour plot corresponding to the unilateral compression experiment, which shows that the deformation is concentrated in the distal airbag region. Figure 6 (3) in the figure demonstrates that the stent exhibits low stiffness and high compliance under vertical compression. With one end of the stent fixed and the other end subjected to a vertical displacement of 8 mm, the simulation results show that the maximum stress is 23.2 MPa, the maximum principal strain is 0.024 N, and the maximum reaction force is only 0.014 N. This result indicates that the stent has excellent flexibility and low stiffness response under compression, which can adapt to radial pressure changes in the venous sinus and avoid excessive compression damage to the vessel wall.

[0075] Axial torsion condition: Figure 5 Figure 5(b) shows the displacement contour plot corresponding to the axial torsion test, which shows the uniform deformation and torsion compatibility. Figure 6 Figure (1) shows the stress-displacement curve corresponding to the axial torsion test, which confirms the enhanced torsional resistance of the multi-bag structure. With one end of the stent fixed and the other end subjected to a 720° rotational displacement, simulation results show that the stress distribution is uniform, the maximum von Mises stress is 65 MPa, the maximum principal strain is 0.026, and the stress is mainly concentrated in the area occluding the tennis ball 11. This result indicates that the stent has strong resistance to torsional deformation, meeting the operational requirements of intraoperative longitudinal rotation adjustment and avoiding structural damage during torsion.

[0076] Three-point bending condition: Figure 5 Figure 5(d) shows the displacement contour plot corresponding to the three-point bending test, which shows the stress concentration phenomenon in the transition region. Figure 6 Figure (4) shows the stress-displacement curves corresponding to the three-point bending test, highlighting the cantilever deformation behavior of the support and the low reaction force under bending conditions. When an 8mm vertical downward displacement is applied at the mid-span of the support, the simulation results show that the maximum stress is 23.2MPa and the maximum principal strain is 3.79×10⁻⁶. -4 The reaction force is only 0.008N, with stress concentrated in the tennis ball connection transition zone. This indicates that the tennis ball connection transition zone is a key area for deformation control, and that the stent exhibits excellent compliance under bending loads, allowing it to smoothly pass through the right-angle bend of the venous sinus, reducing pushing resistance and the risk of jamming.

[0077] The maximum stress values ​​under all the above simulation conditions are much lower than the yield strength of nickel-titanium alloy wire 1, proving that the stent in this embodiment has a sufficient mechanical safety margin and can ensure the structural reliability during the operation.

[0078] 2. In vitro mechanical testing; The finished support obtained in Example 1 was subjected to overall mechanical performance testing to verify its structural consistency and functional reliability, such as... Figure 7 and Figure 8 As shown, Figure 8 The figure shows the load-displacement curves for the flat plate compression test (solid line) and the three-point bending test (dashed line).

[0079] Three-point bending test: This test simulates the working conditions of a stent passing through a curved area of ​​a blood vessel, such as... Figure 7 As shown in Figure B, the prefabricated stent is placed between two fixed stents, and a load is applied at the midpoint to simulate the bending stress at a vein bend. Figure 8 As shown, the test results indicate that the stent can withstand a peak load of 1.47 N at a maximum loading displacement of approximately 4.0 mm; the load-displacement curve exhibits a stable linear upward trend, with no structural instability, buckling, or suture breakage. This result demonstrates that the stent possesses excellent bending resistance and axial flexibility, adapting to the tortuous anatomy of the venous sinus and preventing stent breakage during surgery.

[0080] Flat plate compression test: This test simulates radial compression conditions during catheter advancement and stent-vessel wall attachment, such as... Figure 7 As shown in Figure A, the prefabricated stent is placed between two rigid plates, and a progressive vertical load is applied to simulate the radial compression and vessel wall adhesion during catheter advancement. Figure 8 As shown, the test results indicate that within a displacement range of 0-0.65 mm, the maximum load borne by the stent does not exceed 0.0045 N; the load-displacement curve is smooth, with no obvious inflection point or hysteresis. This reflects the stent's excellent radial compliance and stable compressive response, ensuring that the stent provides effective support when attached to the vessel wall without causing excessive compression damage.

[0081] Therefore, in vitro mechanical tests all showed that the scaffold exhibited stable compliant mechanical behavior, with no signs of structural failure. The low reaction force and smooth curves indicate that, under simulated in vitro conditions, the scaffold possesses excellent radial compliance, flexural flexibility, and structural integrity.

[0082] (ii) Experimental testing; To further verify the practical application effect of the stent, this embodiment validated the stent deployment and thrombectomy capability in a 1:1 in vitro model of venous sinuses 3D printed based on head and neck CE-MRV data. The specific validation results are as follows: Navigability and controllability: such as Figure 4 As shown, in in vitro model testing, the stent can be successfully delivered to target venous sinus regions such as the superior sagittal sinus, sigmoid sinus, and transverse sinus, and allows for axial reciprocating motion and longitudinal rotation. This result indicates that the stent has good operability and controllability, allowing operators to precisely control the stent's movement and posture adjustment within the venous sinuses, meeting the delivery requirements under complex anatomical pathways.

[0083] Vascular adaptability: Within venous segments with a diameter of 7-10 mm, the stent achieves good apposition to the vessel wall through adaptive structural adjustment, ensuring full contact between the stent and the vessel wall. In curved sections with angles exceeding 120°, the stent maintains stable deployment without significant deformation. This demonstrates that the stent can adapt to the diameter variations and irregular cross-sectional shapes of the venous sinus (narrower anteriorly and wider posteriorly), solving the problem of poor apposition of existing stents.

[0084] Thrombus capture capability: Thrombectomy tests using thrombus analogues showed that the three-tendon design enables multi-segment coordinated expansion, effectively anchoring and encapsulating the thrombus, significantly reducing the risk of thrombus escape during retrieval. Compared to traditional single-segment or double-tendon stents, the three-tendon structure of this embodiment provides multiple layers of thrombus protection, improving the success rate of thrombus retrieval.

[0085] In summary, this invention, based on the finite element simulation-optimized braided configuration and the hyperelastic properties of nickel-titanium alloy wire 1, and through systematic mechanical performance evaluation (axial tension, compression, torsion, and bending), confirms that the maximum von Mises stress of the stent under various complex loads (such as 80.2 MPa under axial tension) is far lower than the yield strength of nickel-titanium alloy wire 1, possessing sufficient mechanical safety margin. This effectively avoids stent fracture or permanent damage caused by excessive deformation during surgery. The smooth, hysteresis-free load-displacement curves shown in in vitro mechanical tests further demonstrate that it has good structural consistency and fatigue resistance as a finished product, ensuring its reliability for repeated use in a single surgery.

[0086] (III) Biocompatibility testing: To ensure the scaffold's suitability for intracranial implantation, the biocompatibility of the finished scaffold provided in Example 1 was evaluated: the heat-set mesh framework was placed in simulated body fluid for ion release testing; the nickel ion release was low, meeting the ion release standards for implantable medical devices. Simultaneously, an in vitro cytotoxicity experiment was conducted, where the scaffold material was co-cultured with cells, and cell morphology and proliferation were observed; the results showed no significant cytotoxicity. These evaluation results indicate that the scaffold structure of this embodiment has good biocompatibility, is suitable for intracranial application, and can avoid triggering immune rejection or toxic reactions.

[0087] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0088] It should also be noted that, in this document, the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device.

Claims

1. A multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent, characterized in that, The support includes: The mesh skeleton is fabricated from shape memory alloy using three-dimensional weaving technology. From distal to proximal, the mesh skeleton is sequentially woven with occlusion tennis balls, embedding tennis balls, and control tennis balls. When the mesh skeleton is implanted into the target cerebral venous sinus, the occlusion tennis balls form a physical barrier in front of the thrombus generated within the target cerebral venous sinus to prevent its forward movement. The embedding tennis balls provide radial support to embed the thrombus and achieve anchoring. The control tennis balls are pulled to achieve directional control of the mesh skeleton. An optical fiber pressure sensor is mounted on the mesh skeleton to collect pressure signals from the mesh skeleton during the thrombectomy process.

2. The multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent according to claim 1, characterized in that, The stent is used to connect to a control system, which includes a control handle and multiple microguidewires. One end of each microguidewire is connected to the control handle, and the other end is connected to each tennis ball in a corresponding manner. Each microguidewire is used to adjust the shape parameters of the corresponding tennis ball so that each tennis ball can be independently adapted to the anatomical structure of different segments of the target cerebral venous sinus.

3. The multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent according to claim 2, characterized in that, The blocking tennis ball, the embedded tennis ball, and the control tennis ball together form a gradient functional zone; the gradient functional zone is composed of a breaking basket area, a capture / breaking combination area, and a capture basket area; wherein... The broken basket area includes the blocking tennis ball, the embedded tennis ball, and the area between the two, and is used to break up adhesive thrombi. The capture / fragmentation combination zone includes the area where the embedded tennis ball is located, used to anchor the thrombus, and at the same time to perform secondary fragmentation on the thrombus after initial fragmentation by the fragmentation basket zone; The capture basket area includes a connection area between the control tennis ball and the embedded tennis ball, used to dynamically wrap the thrombus.

4. The multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent according to claim 3, characterized in that, The connecting region is connected to the microguidewire so that the degree of closure of the connecting region can be adjusted by the microguidewire, thereby forming the dynamically shrinkable capture basket area.

5. A multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent according to claim 1, characterized in that, The net deployment area of ​​the blocking tennis ball, the embedded tennis ball, and the control tennis ball increases from small to large.

6. The multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent according to claim 1, characterized in that, The blocking tennis ball, the embedded tennis ball, and the control tennis ball are arranged end-to-end, and adjacent tennis balls are naturally transitioned between each other through the mesh framework; and, The fiber optic pressure sensor is located at the far end of the mesh skeleton near the blocking tennis ball.

7. A multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent according to any one of claims 1-6, characterized in that, The shape memory alloy includes nickel-titanium alloy wire, and the nickel-titanium alloy wire is heat-set after weaving to give it shape memory properties and low ion release properties.

8. A method for preparing a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent, characterized in that the method... include: Nickel-titanium alloy wire is selected as the braiding material. Through three-dimensional braiding technology, a mesh skeleton with blocking tennis balls, embedding tennis balls and control tennis balls is integrally formed along the braiding direction. The blocking tennis ball is used to form a physical barrier in front of the thrombus generated in the target cerebral venous sinus to prevent the thrombus from moving forward. The embedding tennis ball is used to provide radial support force to embed the thrombus and achieve anchoring. The control tennis ball is pulled to achieve directional control of the mesh skeleton. The mesh skeleton is heat-set to give it shape memory properties and low ion release properties. By integrating an optical fiber pressure sensor onto the mesh framework, a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent is obtained.

9. The method for preparing a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent according to claim 8, characterized in that, The method also includes: Multiple microguidewires are connected to the occlusion tennis ball, the embedded tennis ball, and the control tennis ball respectively, and the microguidewires are connected to the control handle to complete the combination of the thrombectomy bracket and the control system.

10. The method for preparing a multi-segment pressure-guided three-ball braided cerebral venous sinus thrombectomy stent according to claim 8, characterized in that, The sensing head of the fiber optic pressure sensor is fixed to the far end of the mesh frame, and the transmission fiber of the fiber optic pressure sensor is extended along the mesh frame.

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