Rigidity-variable interventional medical access catheter

Abstract

The invention discloses a rigidity-variable interventional medical access catheter which comprises a catheter body and a handle, the catheter body comprises a lining tube, the lining tube is sleeved with a reinforcing tube, the reinforcing tube is sleeved with a supporting tube, and the supporting tube is covered with a flexible outer membrane layer capable of being filled and expanded; the handle comprises a first channel communicated with an inner hole of the lining pipe and a second channel communicated with a space between the supporting pipe and the flexible outer film layer, when a medium is filled through the second channel, the flexible outer film layer is attached to the outer surface of the supporting pipe, and when the medium is filled through the second channel, the flexible outer film layer is separated from the supporting pipe to form a separation space. Compared with the prior art, the separation space is formed between the outer membrane layer and the supporting tube to form buffering, so that the outer membrane layer has flexibility to reduce the rigidity of the catheter so as to facilitate conveying in a blood vessel, when the outer membrane layer is attached to the outside of the supporting tube, the separation space disappears, the rigidity of the catheter is increased, and the stability of the catheter is guaranteed; instruments such as embolism materials or supports can be accurately placed in place, and the treatment effect is improved.

Description

Technical Field

[0001] The present invention relates to a medical device, in particular to an interventional medical access catheter with variable stiffness. Background Art

[0002] Interventional surgery, as a minimally invasive treatment method, occupies an increasingly important position in modern medicine. Delivering the instrument to the target blood vessel location is the key to the success of interventional surgery. During interventional surgery, soft catheters can pass through tortuous and small blood vessels to reach more distal blood vessels. The harder catheters can provide sufficient support to maintain the stability of the lumen, avoid bends, and provide support for other instruments to pass through the lumen. However, the human vascular system has a complex anatomical structure, and there are great differences in the morphology, diameter, and degree of curvature of the blood vessels of different patients. When faced with a complex and changing vascular environment, catheters with fixed rigidity often find it difficult to pass smoothly through narrow, tortuous, or branched blood vessel segments. The position and direction of the catheter may need to be adjusted repeatedly, which increases the operation time and the patient's pain, and also increases the risk of complications such as vascular perforation and dissection. Fixed soft catheters cannot provide sufficient support, which will cause the lumen to retreat, shift, or be difficult to deliver when passing other instruments or preparations. The limitations of traditional fixed rigidity catheters in tortuous blood vessels are: 1. Rigid catheters have poor permeability. The tortuous vascular pathways are complex, and catheters with fixed stiffness are difficult to adapt to multi-angle bends, resulting in increased pushing resistance. This may cause the catheter to become stuck or unable to reach the target location, leading to surgical failure.

[0003] 2. Soft catheters lack support. During vascular interventional procedures, such as stent implantation and microsphere delivery, the catheter requires stable support. Access catheters that are too soft may not provide sufficient support for these procedures, potentially leading to inaccurate stent placement and microsphere delivery jams.

[0004] 3. The operation time is prolonged, and the surgeon needs to repeatedly adjust the catheter position according to the angiography, which prolongs the operation time.

[0005] 4. Increased risk of complications and vascular damage: Forced passage may damage the vascular lining, even causing perforation or dissection. Vasospasm: Mechanical friction between the catheter and the vessel wall may induce spasm. Summary of the Invention

[0006] The purpose of the present invention is to provide an interventional medical access catheter with variable stiffness, and the technical problem to be solved is to achieve variable stiffness of the catheter.

[0007] To solve the above problems, the present invention adopts the following technical solutions: a variable stiffness interventional medical access catheter, comprising a catheter and a handle arranged at the proximal end of the catheter, the catheter comprising an inner lining tube, a reinforcement tube for improving the structural strength of the catheter is arranged outside the inner lining tube, a support tube is arranged outside the reinforcement tube, and the support tube is covered with an inflatable and expandable flexible outer membrane layer, the handle comprises a first channel connected to the inner hole of the inner lining tube, and a second channel connected to the space between the support tube and the flexible outer membrane layer. When the medium is filled through the second channel, the flexible outer membrane layer is attached to the outer surface of the support tube. When the medium is filled through the second channel, the flexible outer membrane layer is separated from the support tube to form a separation space to reduce the stiffness of the catheter.

[0008] Furthermore, the flexible outer film layer is provided with at least one layer.

[0009] Furthermore, each layer of the flexible outer film has a thickness of 0.001-0.003 inches.

[0010] Furthermore, the flexible outer membrane layer is made of polyurethane, polytetrafluoroethylene, expanded polytetrafluoroethylene, or polypropylene.

[0011] Furthermore, the support tube is a metal cutting tube with a cutting through hole provided on the tube body.

[0012] Furthermore, the support tube is made of stainless steel or nickel-titanium alloy.

[0013] Furthermore, the reinforcement tube is a spring tube.

[0014] Furthermore, the reinforcement tube is made of one or more of stainless steel, nickel-titanium alloy, tungsten wire or polymer fiber.

[0015] Furthermore, the inner diameter of the liner tube is 0.016-0.074 inches and the wall thickness is 0.0005-0.003 inches.

[0016] Furthermore, the inner liner tube is made of polytetrafluoroethylene, polyethylene or a composite material with a biochemical coating.

[0017] Compared with the prior art, the present invention sequentially arranges a reinforcing tube, a support tube and an outer membrane layer outside the inner lining tube. When the space between the support tube and the outer membrane layer is filled with a medium, the outer membrane layer can be separated from the support tube to form a separation space, and the separation space is filled with the medium. At this time, there is a separation space between the outer membrane layer and the support tube to form a buffer. Therefore, the outer membrane layer has softness to reduce the rigidity of the catheter to facilitate intravascular delivery. When the outer membrane layer is attached to the outside of the support tube, the separation space disappears and the rigidity of the catheter increases to ensure the stability of the catheter, ensure that embolic materials or devices such as stents can be accurately placed in place, and improve the treatment effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of the working mode 1 of the present invention.

[0019] Figure 2 yes Figure 1 Schematic diagram of the structure in the AA direction.

[0020] Figure 3 It is a structural diagram of the second working mode of the present invention.

[0021] Figure 4 yes Figure 3 Schematic diagram of the structure in the B-B direction.

[0022] Figure 5 It is a structural schematic diagram of the first support tube of the present invention.

[0023] Figure 6 It is a structural schematic diagram of the second support tube of the present invention.

[0024] Figure 7 It is a schematic diagram of the connection between the handle and the catheter of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] In the present invention, the distal end refers to the end away from the surgical operator; the proximal end refers to the end close to the surgical operator.

[0027] In the present invention, the first working mode is a supporting mode, which is used for supporting the device in the blood vessel; the second working mode is a transporting mode, which is used for transporting the device in the blood vessel.

[0028] like Figure 1 、 Figure 2 and Figure 7 As shown, the present invention discloses a variable stiffness interventional medical access catheter, comprising a catheter 1 and a handle 2 arranged at the proximal end of the catheter 1, wherein the catheter 1 comprises an inner lining tube 3, a reinforcement tube 4 for improving the structural strength of the catheter 1 is provided on the outer surface of the inner lining tube 3, and a support tube 5 is provided on the outer surface of the reinforcement tube 4. In the present invention, the reinforcement tube 4 is fixed on the outside of the inner lining tube 3, and the support tube 5 is fixed on the outside of the reinforcement tube 4. The outside of the support tube 5 is covered with an inflatable and expandable flexible outer membrane layer 6, and there is a space between the outer membrane layer 6 and the support tube 5 that can be filled with a medium. The handle 2 comprises a first channel 7 connected to the inner hole of the inner lining tube 3, and a second channel 8 connected to the space between the support tube 5 and the flexible outer membrane layer 6. When the medium is filled through the second channel 8, the flexible outer membrane layer 6 is attached to the outer surface of the support tube 5. When the medium is filled through the second channel 8, the flexible outer membrane layer 6 is separated from the support tube 5 to form a separation space 10 to reduce the stiffness of the catheter 1.

[0029] In the present invention, the medium may be physiological saline.

[0030] like Figure 7 As shown, in the present invention, the first channel 7 is formed on the axis of the handle 2, and the second channel 8 is formed outside the first channel 7, which is annular. The proximal ends of the lining tube 3, the reinforcing tube 4 and the support tube 5 are all connected and fixed to the distal end of the first channel 7, so that the inner hole of the lining tube 3 is connected with the first channel 7, and the proximal end of the outer film layer 6 is connected and fixed to the distal end of the second channel 8, so that the medium can enter between the outer film layer 6 and the support tube 5 from the second channel 8. A second interface 9 connected to the second channel 8 is provided on the outside of the handle 2, and the first channel 7 passes through the handle 2 axially.

[0031] In the present invention, the material of the inner liner 3 is a smooth material with a low friction coefficient, such as polytetrafluoroethylene, high-density polyethylene, a composite material coated with a chemical coating with good biocompatibility, such as polypropylene coated with silicone oil or polyvinyl pyrrolidone. It effectively reduces the friction of the guide wire or other instruments passing through the inner liner of the catheter, and reduces the difficulty of the catheter in place or the lack of catheter followability due to excessive friction. In order to reduce the outer diameter of the catheter as a whole, the inner liner usually has a wall thickness of 0.0005-0.003 inches, an inner diameter of 0.016-0.074 inches, and an outer diameter of 0.017-0.077 inches.

[0032] Reinforcement tube 4 utilizes a coiled spring tube made of stainless steel (such as 304 or 316 stainless steel), nickel-titanium alloy, tungsten wire, or high-strength polymer fiber. Its primary function is to enhance the catheter's structural strength. The wire diameter ranges from 0.0005 to 0.008 inches, ensuring the coiled spring's strength while ensuring a close fit to the inner lining, reducing the catheter's overall size and increasing its flexibility. During catheter insertion and manipulation, the vessel exerts various pressures and friction on the catheter. The coiled spring effectively enhances the catheter's resistance to pressure, preventing deformation or damage from these forces. When navigating narrow or tortuous vessels, the coiled spring helps maintain the catheter's shape, ensuring the lumen's patency and enabling smooth passage of a guidewire or other instrument.

[0033] The support tube 5 is a metal cutting tube (such as Figures 5 to 7 (As shown), the cutting holes are staggered throughout the tube body. This component is precision laser-cut. It is supported by stainless steel or nickel-titanium alloy, with the cutting holes formed in the tube body to control its rigidity. The inner diameter of the support tube matches the outer diameter of the reed tube, with a typical clearance of 0.001-0.002 inches. The laser cutting process produces cutting residues, such as tiny metal chips and oxides. These are treated with ultrasonic water washing, pickling, or sand and stone passivation.

[0034] The outer membrane layer 6 includes at least one layer, which is a thin-walled flexible polymer (single layer thickness is about 0.001-0.003 inches), which can be polyurethane, polytetrafluoroethylene, expanded polytetrafluoroethylene or polypropylene. When the syringe is connected to the second interface 9, it can be filled with a small amount of medium (physiological saline) and adjusted to the delivery mode. The outer membrane layer 6 is separated from the metal support tube (such as Figure 3 and Figure 4 As shown in the figure), at this time, a separation space is formed between the outer membrane layer 6 and the support tube 5 for buffering, thereby reducing the rigidity of the catheter, improving the flexibility of the catheter, and facilitating the placement of the catheter. When the liquid under the outer membrane layer 6 is withdrawn by the syringe, the outer membrane layer is attached to the support tube 6 and adjusted to the "support mode" (as shown in the figure). Figure 1 and Figure 2 As shown in the figure, at this time, the separation space disappears and the rigidity of the catheter increases, which is conducive to the stability of the catheter, ensuring that the embolic material or stent and other devices can be accurately placed in place, thereby improving the treatment effect.

[0035] like Figure 5 As shown, the support tube 5 in the present invention can be cut into the following structure, wherein a group of cutting holes 51 are cut on the tube body wall on opposite sides along the axial direction of the tube body, and the center lines of two adjacent groups of cutting holes 51 are arranged in a cross-staggered manner, so that the tube body of the support tube is connected by two opposite connecting parts 52 between a plurality of ring bodies. This structure, which is arranged in a straight line relative to the center line of the cutting holes, has the same bending force in all circumferential directions, so that the catheter can bend in any direction in the blood vessel with the same bending force, thereby making the catheter have better passability.

[0036] like Figure 6 As shown, the support tube 5 of the present invention can also be configured with staggered cutout holes 51 arranged along its axial direction, with adjacent cutout holes 51 arranged at a 180-degree angle, and with the cutout holes 51 occupying at least half of the circle of the plane in which they lie. This greater proportion of cutout holes enhances the flexibility of the support tube and improves its stability. When bent, it can more firmly maintain its target position, reducing catheter movement and displacement, and ensuring consistent and accurate treatment.

[0037] Of course, the support tube 5 in the present invention can also be a metal cutting tube in the prior art.

[0038] This invention allows for adjustable modes based on the surgeon's needs. The tracking capabilities of a soft catheter and the supportive capabilities of a stiffer catheter enhance surgical safety, effectiveness, and precision. The unique variable stiffness design allows for better adaptation to clinical needs.

[0039] Improving surgical precision: Precise positioning is crucial in tortuous vascular interventions. The variable-stiffness catheter, in delivery mode, exhibits excellent flexibility, enabling it to nimbly navigate tortuous nerves and vessels and accurately reach the lesion site. Upon reaching the target location, the catheter switches to support mode, increasing its stiffness and providing stable support for interventional device manipulation, facilitating precise stent placement and drug delivery, and enhancing surgical precision.

[0040] Enhanced vascular adaptability: Human vascular structure is complex and variable, with vascular morphology, degree of tortuosity, and stenosis varying from patient to patient. Variable-stiffness catheters adjust their stiffness based on the specific conditions of the vessel. When encountering narrow or extremely tortuous vessels, the catheter's stiffness is reduced to facilitate smooth passage. In relatively straight segments, the stiffness is increased to maintain stability, minimize damage to the vessel wall, and reduce the risk of complications such as rupture and thrombosis.

[0041] Improved surgical safety: Traditional catheters, due to their fixed stiffness, can exert excessive pressure on the vessel wall during operation, leading to vascular damage. The variable stiffness catheter reduces pressure and friction on the vessel wall by adjusting stiffness at different stages. In delivery mode, the flexible catheter reduces mechanical irritation to the vessel wall; in support mode, the stable support structure effectively prevents catheter movement or displacement, thereby improving surgical safety.

[0042] Optimizing Treatment Outcomes: Variable stiffness catheters are ideally suited for use with interventional devices in the treatment of neurovascular diseases such as cerebral aneurysms and arteriovenous malformations. Their stable support ensures precise placement of embolic materials or stents, enhancing treatment outcomes. The catheter's flexibility also allows for a more comprehensive visualization of the lesion, supporting the development of more precise treatment plans.

Claims

1. A variable stiffness interventional medical access catheter, comprising a catheter (1) and a handle (2) disposed at the proximal end of the catheter (1), characterized in that: The catheter (1) comprises an inner lining tube (3), a reinforcement tube (4) for improving the structural strength of the catheter (1) is provided on the outer surface of the inner lining tube (3), a support tube (5) is provided on the outer surface of the reinforcement tube (4), and the support tube (5) is covered with an inflatable and expandable flexible outer membrane layer (6). The handle (2) comprises a first channel (7) connected to the inner hole of the inner lining tube (3), and a second channel (8) connected to the space between the support tube (5) and the flexible outer membrane layer (6). When a medium is filled through the second channel (8), the flexible outer membrane layer (6) is attached to the outer surface of the support tube (5). When a medium is filled through the second channel (8), the flexible outer membrane layer (6) is separated from the support tube (5) to form a separation space, so as to reduce the rigidity of the catheter (1).

2. The variable stiffness interventional medical access catheter according to claim 1, characterized in that: The flexible outer film layer (6) is provided with at least one layer.

3. The variable stiffness interventional medical access catheter according to claim 2, characterized in that: Each layer of the flexible outer film layer (6) has a thickness of 0.001-0.003 inches.

4. The variable stiffness interventional medical access catheter according to claim 4, characterized in that: The flexible outer membrane layer (6) is made of polyurethane, polytetrafluoroethylene, expanded polytetrafluoroethylene, and polypropylene.

5. The variable stiffness interventional medical access catheter according to claim 1, characterized in that: The support tube (5) is a metal cutting tube with a cutting through hole provided on the tube body.

6. The variable stiffness interventional medical access catheter according to claim 5, characterized in that: The support tube (5) is made of stainless steel or nickel-titanium alloy material.

7. The variable stiffness interventional medical access catheter according to claim 1, characterized in that: The reinforcing tube (4) is a spring-wound tube.

8. The variable stiffness interventional medical access catheter according to claim 7, characterized in that: The reinforcement tube (4) is made of one or more of stainless steel, nickel-titanium alloy, tungsten wire or polymer fiber.

9. The variable stiffness interventional medical access catheter according to claim 1, characterized in that: The inner diameter of the liner tube (3) is 0.016-0.074 inches and the wall thickness is 0.0005-0.003 inches.

10. The variable stiffness interventional medical access catheter according to claim 9, characterized in that: The inner lining tube (3) is made of polytetrafluoroethylene, polyethylene or a composite material with a biochemical coating.

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