Micro catheter with expandable far end

Abstract

The microcatheter comprises a protective tube, one end of the protective tube is fixedly connected with a tail tube, and the end, away from the tail tube, of the protective tube is provided with a catheter structure; the catheter structure comprises an outer tube fixedly connected with the protective tube, an inner tube is slidably connected into the outer tube, an elastic tube is fixedly connected to the end, away from the protective tube, of the inner tube, an expansion frame is embedded in the elastic tube, a driving sleeve is arranged on the protective tube, and the driving sleeve is fixedly connected with the inner tube. According to the endoscopic microcatheter, by arranging the catheter structure, when a reverse guide wire technology is started and a forward guide wire is introduced into the endoscopic microcatheter, the inner tube can be deduced to slide towards the forward guide wire, so that the inner tube extends out of the outer tube, then the expansion frame drives the elastic tube to expand, and the end face of the elastic tube can completely abut against the inner diameter of the forward guide wire; in this way, the forward guide wire can enter the reverse micro-catheter smoothly, and operation of medical staff is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of communication devices, and particularly to a distally expandable microcatheter. Background Art

[0002] In CTO interventional therapy, cases of chronic total occlusion of coronary arteries are often encountered. At this time, due to the proximal fibrotic cap of the lesion often becoming extremely hard due to long-term fibrosis and calcification, the antegrade guide wire (especially a hard guide wire) may be difficult to penetrate or prone to deviating from the true lumen, resulting in difficulty in passing the antegrade guide wire through the occluded segment. Also, because the distal fibrotic cap of the occluded segment is usually thinner or has a looser structure, the guide wire is more likely to penetrate into the true lumen. Therefore, operators often choose to initiate the retrograde guide wire technique through a good collateral circulation to form a passage.

[0003] In the prior art, when passing an antegrade guide wire into a retrograde microcatheter, operators often need to spend a lot of time inserting the antegrade guide wire into the retrograde microcatheter, which may significantly extend the operation time, increasing the physical consumption of medical staff during the operation and the operation risk. For this reason, we propose a distally expandable microcatheter to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems existing in the prior art, and to propose a distally expandable microcatheter.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: A distally expandable microcatheter, including a protective tube, one end of the protective tube is fixedly connected with a tail tube, and a catheter structure is arranged at the end of the protective tube away from the tail tube; The catheter structure includes an outer tube fixedly connected with the protective tube, an inner tube is slidably connected inside the outer tube, one end of the inner tube away from the protective tube is fixedly connected with an elastic tube, an expansion frame is embedded in the elastic tube, a driving sleeve is arranged on the protective tube, and the driving sleeve is fixedly connected with the inner tube.

[0006] Preferably, the elastic tube includes a superelastic silicone tube fixedly connected with the inner tube, a sinking groove is arranged on the superelastic silicone tube, the expansion frame is arranged in the sinking groove, a protective layer is further arranged on the outer wall of the superelastic silicone tube, the protective layer wraps the expansion frame, and a plurality of connection points are arranged between the protective layer and the superelastic silicone tube.

[0007] Preferably, the expansion frame includes a top rod, the top rod is fixedly connected with the inner tube, a clamping ring is fixedly connected to the end of the top rod away from the inner tube, and a plurality of driving rods arranged in a surrounding manner are fixedly connected to the clamping ring.

[0008] Preferably, the driving rod is made of nitinol alloy.

[0009] Preferably, the drive sleeve includes a push ring slidably connected to the inner wall of the protective tube. A connecting rod is fixedly connected to the push rod, and a clamping ring is fixedly connected to the connecting rod. The clamping ring is fixedly connected to the inner tube. A strip-shaped opening is formed in the protective tube, and a push block is slidably connected in the strip-shaped opening. The push block is fixedly connected to the clamping ring.

[0010] Preferably, symmetrically arranged retaining pieces are fixedly connected to the push block, and the length of the retaining piece is greater than the length of the strip-shaped opening.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In the present invention, by providing a catheter structure, when starting the reverse guide wire technique, when the forward guide wire is introduced into the inner micro catheter, it can be inferred that the inner tube slides towards the forward guide wire direction, causing the inner tube to extend out of the outer tube. Subsequently, the expansion frame drives the elastic tube to expand, and the end face of the elastic tube can completely abut against the inner diameter of the forward catheter, so that the forward guide wire can be smoothly introduced into the reverse micro catheter, facilitating the operation of medical staff.

[0012] 2. In the present invention, the elastic tube composed of the super-elastic silicone tube and the protective layer can ensure that the expansion frame can drive the elastic tube to expand. After the protective layer abuts against the inner diameter of the forward catheter, the super-elastic silicone tube will also deform as a whole, without hindering the guide wire from entering the reverse micro catheter. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of a distal expandable micro catheter proposed by the present invention; Figure 2 It is a schematic diagram of the first working state structure of a distal expandable micro catheter during docking proposed by the present invention; Figure 3 It is a schematic diagram of the second working state structure of a distal expandable micro catheter during docking proposed by the present invention; Figure 4 It is a schematic cross-sectional structure diagram of the protective tube of a distal expandable micro catheter proposed by the present invention; Figure 5 It is a schematic side cross-sectional structure diagram of the elastic tube of a distal expandable micro catheter proposed by the present invention; Figure 6 It is a schematic cross-sectional structure diagram of the elastic tube of a distal expandable micro catheter proposed by the present invention.

[0014] In the figure: 1. Protective tube; 2. Tail tube; 3. Outer tube; 4. Inner tube; 5. Super-elastic silicone tube; 6. Protective layer; 7. Connection point; 8. Thumb rod; 9. Connection ring; 10. Drive rod; 11. Push ring; 12. Connecting rod; 13. Clamping ring; 14. Retaining piece; 15. Push block; 16. Forward catheter. DETAILED DESCRIPTION OF THE INVENTION

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0016] Referring to Figure 1-6 , a distally expandable microcatheter includes a sheath 1. One end of the sheath 1 is fixedly connected to a tail tube 2, and a catheter structure is provided at the end of the sheath 1 away from the tail tube 2; The catheter structure includes an outer tube 3 fixedly connected to the sheath 1. An inner tube 4 is slidably connected inside the outer tube 3. One end of the inner tube 4 away from the sheath 1 is fixedly connected to an elastic tube. An expansion frame is embedded in the elastic tube. A drive sleeve is provided on the sheath 1, and the drive sleeve is fixedly connected to the inner tube 4; Among them, the outer tube 3 is a double-layer tube, the outer layer is made of pebax material with gradually changing hardness, and the inner layer is made of PTFE material. The inner tube 4 is a three-layer tube, the outer layer is pebax, the middle layer is made of stainless steel braided material, and the inner layer is made of pefe material. This expandable microcatheter is used as a reverse microcatheter. During use, after this microcatheter penetrates to a position near the forward catheter 16, align the elastic tube with the forward catheter 16, and then infer the drive sleeve to drive the inner tube 4 to move towards the forward catheter 16. At this time, the elastic tube is inserted into the forward catheter 16. At this time, the expansion frame deforms under the action of its own elasticity, driving the elastic tube to expand. The end face of the elastic tube can completely abut against the inner diameter of the forward catheter 16, so that the forward guide wire can enter this microcatheter, which greatly facilitates the operation of medical staff, shortens the operation time, reduces the physical consumption of medical staff, reduces the operation risk, and ensures that the guide wire can pass the instrument through the occluded end to reach the designated position.

[0017] Furthermore, the elastic tube includes a superelastic silicone tube 5 fixedly connected to the inner tube 4. A sink is provided on the superelastic silicone tube 5. The expansion frame is arranged in the sink. A protective layer 6 is further provided on the outer wall of the superelastic silicone tube 5. The protective layer 6 wraps the expansion frame, and a plurality of connection points 7 are provided between the protective layer 6 and the superelastic silicone tube 5; In this design, the superelastic silicone tube 5 will deform under the drive of the expansion frame, and the protective layer 6 ensures that the expansion frame drives the elastic tube to expand, and through a plurality of connection points 7, ensures that the superelastic silicone tube 5 can expand stably. In addition, the protective layer 6 is also used to fit with the inner tube 4 to prevent human tissues or body fluids from seeping between the inner tube 4 and the outer tube 3 during the insertion of this microcatheter.

[0018] Furthermore, the expansion frame includes a top rod 8, which is fixedly connected to the inner tube 4. One end of the top rod 8 away from the inner tube 4 is fixedly connected with a connecting ring 9, and a plurality of surrounding driving rods 10 are fixedly connected to the connecting ring 9; In this design, by setting the top rod 8 in cooperation with the connecting ring 9, it can be ensured that the plurality of driving rods 10 can all extend out of the outer tube 3 driven by the inner tube 4, avoiding the elastic deformation of the inner tube 4, resulting in only some of the driving rods 10 extending out together with the elastic tube, ensuring the docking effect between the micro catheter and the forward catheter 16, and also used to avoid the situation that the elastic tube made of highly elastic silicone material is difficult to be pushed out of the outer tube 3 due to its own deformation.

[0019] Furthermore, the driving rod 10 is made of nitinol, also known as shape memory alloy, which is the core component for driving the expansion of the elastic tube by utilizing its characteristics.

[0020] Furthermore, the driving sleeve includes a push ring 11 slidably connected to the inner wall of the protective tube 1. A connecting rod 12 is fixedly connected to the push rod, and a clamping ring 13 is fixedly connected to the connecting rod 12. The clamping ring 13 is fixedly connected to the inner tube 4. A strip-shaped opening is formed in the protective tube 1, and a push block 15 is slidably connected in the strip-shaped opening. The push block 15 is fixedly connected to the clamping ring 13; In this design, when the user needs to withdraw the elastic tube from the outer tube 3, push the push block 15 outside the protective tube 1 to drive the push ring 11 to move towards the outer tube 3. At this time, the connecting rod 12 drives the clamping ring 13 to move, and then uses the clamping ring 13 to drive the inner tube 4 to move towards the forward catheter 16, finally realizing the pushing out of the elastic tube from the outer tube 3, so that it expands under the drive of the expansion frame.

[0021] Furthermore, symmetrically arranged blocking pieces 14 are fixedly connected to the push block 15. The length of the blocking pieces 14 is greater than the length of the strip-shaped opening. The blocking pieces 14 are used to block the strip-shaped opening to prevent foreign objects from entering the inside of the protective tube 1, ensuring the safety of this kind of micro catheter.

[0022] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A distally expandable microcatheter, comprising a sheath tube (1), characterized in that, One end of the protective tube (1) is fixedly connected to a tail tube (2), and a conduit structure is provided at the end of the protective tube (1) away from the tail tube (2). The conduit structure includes an outer tube (3) fixedly connected to the protective tube (1). An inner tube (4) is slidably connected inside the outer tube (3). One end of the inner tube (4) away from the protective tube (1) is fixedly connected to an elastic tube. An expansion frame is embedded in the elastic tube. A drive sleeve is provided on the protective tube (1), and the drive sleeve is fixedly connected to the inner tube (4).

2. The distal-expandable microcatheter according to claim 1, wherein The elastic tube includes a super-elastic silicone tube (5) fixedly connected to the inner tube (4). A sunk groove is provided on the super-elastic silicone tube (5). The expansion frame is arranged in the sunk groove. A protective layer (6) is further provided on the outer wall of the super-elastic silicone tube (5). The protective layer (6) wraps the expansion frame, and a plurality of connection points (7) are provided between the protective layer (6) and the super-elastic silicone tube (5).

3. The distal-expandable microcatheter according to claim 1, wherein The expansion frame includes a top rod (8). The top rod (8) is fixedly connected to the inner tube (4). One end of the top rod (8) away from the inner tube (4) is fixedly connected to a connection ring (9). A plurality of driving rods (10) arranged in a surrounding manner are fixedly connected to the connection ring (9).

4. The distal-expandable microcatheter according to claim 3, characterized in that, The driving rod (10) is made of nitinol.

5. The distal-expandable microcatheter according to claim 1, wherein The drive sleeve includes a push ring (11) slidably connected to the inner wall of the protective tube (1). A connecting rod (12) is fixedly connected to the push rod, and a clamping ring (13) is fixedly connected to the connecting rod (12). The clamping ring (13) is fixedly connected to the inner tube (4). A strip-shaped opening is formed in the protective tube (1), and a push block (15) is slidably connected in the strip-shaped opening. The push block (15) is fixedly connected to the clamping ring (13).

6. The distal-expandable microcatheter according to claim 5, wherein, Symmetrically arranged retaining pieces (14) are fixedly connected to the push block (15). The length of the retaining piece (14) is greater than the length of the strip-shaped opening.

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