Delivery system for woven stents

Abstract

The utility model relates to a conveying system of a woven stent, and relates to the technical field of medical stents. The conveying system of the woven support comprises a push rod assembly and a sheath tube assembly, the push rod assembly comprises an inner tube, a supporting structure is arranged on the inner tube, and the sheath tube assembly comprises a conveying outer sheath. The friction force between the supporting structure arranged on the inner tube and the woven stent is larger than the friction force between the conveying sheath and the woven stent, so that when the conveying sheath moves towards the far end side, the woven stent is supported by the supporting structure and does not easily move along with the conveying sheath; therefore, the problem of pushing failure caused by stacking of the woven stent during pushing can be avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of medical stents, in particular to a conveying system of a braided stent. Background Art

[0002] As an implant, the braided stent is generally delivered to the target location in the patient's body through a delivery system. The push rod of the delivery system is fixed, and the delivery sheath moves toward the distal side to release the braided stent. Therefore, the braided stent is directly pushed out of the delivery sheath by the push rod. If a braided stent without an axial braided cross structure is pushed, stent stacking may occur during the pushing process, thereby increasing the pushing resistance and possibly causing implant failure. Utility Model Content

[0003] The utility model provides a conveying system of a braided stent, which is used to solve at least one of the above-mentioned technical problems.

[0004] The utility model provides a delivery system for a braided stent, comprising:

[0005] a push rod assembly comprising an inner tube; and

[0006] A sheath tube assembly, the sheath tube assembly comprising a delivery outer sheath, the delivery outer sheath being arranged outside the inner tube, and the space between the delivery outer sheath and the inner tube being used to accommodate the braided stent;

[0007] Wherein, a support structure is provided on the inner tube, and the support structure is used to support the braided stent to be transported. The friction force between the support structure and the braided stent is greater than the friction force between the transport outer sheath and the braided stent.

[0008] In one embodiment, the support structure is made of nylon elastomer, thermoplastic polyurethane elastomer or silicone; the delivery sheath includes an inner layer structure for contacting the braided stent, and the inner layer structure is made of polytetrafluoroethylene.

[0009] In one embodiment, the support structure is configured as a threaded strip spirally wound around the outer wall of the inner tube.

[0010] In one embodiment, the thread strip is wound around the outer wall of the inner tube in a double helix form, and the pitch of the thread strip is greater than 1 mm.

[0011] In one embodiment, the thread strip is wound around the outer wall of the inner tube in the form of a single thread or multiple threads.

[0012] In one embodiment, a conical guide head is further provided at the end of the inner tube, and the end of the delivery sheath abuts against the guide head.

[0013] In one embodiment, the push rod assembly further includes an outer tube covering a portion of the inner tube and a push rod connected to the outer tube, the outer tube is made of nylon, and the push rod is made of stainless steel.

[0014] In one embodiment, the thickness of the thread strip is less than (D1-D2) / 2, where D1 is the inner diameter of the outer tube and D2 is the outer diameter of the inner tube.

[0015] In one embodiment, the sheath tube assembly further comprises a Y-shaped valve connected to the delivery outer sheath, and the Y-shaped valve fixes the sheath tube assembly on the push rod via a locking cap thereon.

[0016] In one embodiment, the Y-valve is made of polycarbonate.

[0017] Compared with the prior art, the advantage of the present invention is that the friction between the support structure provided on the inner tube and the braided stent is greater than the friction between the delivery sheath and the braided stent. Therefore, when the delivery sheath moves toward the distal side, the braided stent will be supported by the support structure and will not easily move with the delivery sheath, thereby avoiding the problem of stacking of the braided stent during pushing and resulting in pushing failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings.

[0019] Figure 1 , Figure 2 and Figure 3 They are schematic diagrams of the unfolded structure of the braided stent;

[0020] Figure 4 It is a structural schematic diagram of a delivery system of a braided stent in an embodiment of the utility model;

[0021] Figure 5 yes Figure 4 An enlarged view of the front end side of the conveying system is shown;

[0022] Figure 6 yes Figure 4 A schematic diagram of the structure of the push rod assembly shown (wherein the supporting structure is not shown);

[0023] Figure 7 yes Figure 6 An enlarged view of the front end side of the push rod assembly is shown;

[0024] Figure 8 yes Figure 4 A schematic diagram of the structure of the push rod assembly combined with the support structure;

[0025] Fig. 9 yes Figure 8 an enlarged view of the support structure shown;

[0026] Fig.10 yes Figure 4 A schematic diagram of the structure of the sheath assembly shown;

[0027] Fig.11 yes Fig.10 An enlarged view of the front end side of the sheath assembly is shown;

[0028] Fig.12 It is a structural schematic diagram of a threaded strip forming device of the utility model;

[0029] Fig.13 yes Fig.12 A schematic diagram of the three-dimensional structure of the cutting assembly shown;

[0030] Fig.14 yes Fig.12 A side view of the cutting assembly is shown;

[0031] Reference numerals:

[0032] 1. Push rod assembly; 2. Sheath assembly; 3. Braided stent; 4. Support structure;

[0033] 11. Inner tube; 12. Outer tube; 13. Push rod; 14. Guide head; 15. Handle seat;

[0034] 21. Delivery sheath; 231. Locking cap; 23. Y-type valve; 141. Conical end; 142. Connector;

[0035] 100. Molding device;

[0036] 110, base; 120, cutting assembly; 130, slide rail; 140, driving assembly; 150, positioning seat; 160, hose;

[0037] 121, cutting blade; 122, base; 123, inclined groove; 124, groove;

[0038] 1401. Motor; 1402. Coupling; 1403. Chuck; 1404. Mandrel; 1405. Slider. DETAILED DESCRIPTION

[0039] The utility model will be further described below in conjunction with the accompanying drawings.

[0040] Figure 1 , Figure 2 and Figure 3 Three common braided stents 3 are shown respectively. Figure 1The braided stent 3 shown in FIG. 1 has a cross-interconnected structure in the axial direction, so it can withstand a certain tensile force but cannot be compressed. Figure 2 The braided stent 3 shown is a stent graft composed of wavy rings, which has no interconnected structure in the axial direction and is fixed only by the graft. Figure 3 The braided stent 3 shown is a coated stent woven from monofilaments, which also has no interconnected structure in the axial direction and is fixed only by the coating. The various braided stents 3 mentioned above cannot be compressed when being pushed axially, otherwise the braided stents 3 will be stacked, thereby increasing resistance and possibly causing the problem of pushing failure.

[0041] like Figure 4-Figure 11 As shown, the utility model provides a delivery system for a braided stent to solve the problem that the braided stent 3 is easily stacked and causes delivery failure during delivery. Specifically, the delivery system for a braided stent of the utility model includes a push rod assembly 1 and a sheath assembly 2, and the braided stent 3 is loaded between the push rod assembly 1 and the sheath assembly 2 and pushed at a designated position.

[0042] like Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, the push rod assembly 1 includes a guide head 14, an inner tube 11, an outer tube 12, a push rod 13 and a handle seat 15. The operator can grasp the handle seat 15 when pushing the braided stent 3. Herein, the side close to the handle seat 15 is defined as the distal side, and the side away from the handle seat 15 is defined as the proximal side.

[0043] like Fig.10 and Fig.11 As shown, the sheath tube assembly 2 includes a delivery sheath 21, which is arranged outside the inner tube 11, and the space between the delivery sheath 21 and the inner tube 11 is used to accommodate the braided stent 3 (the braided stent 3 is in a compressed state and loaded between the delivery sheath 21 and the inner tube 11). Therefore, the delivery sheath 21 can play a role in binding the braided stent 3. After reaching the specified position, the delivery sheath 21 moves toward the distal side, that is, the push rod assembly 1 and the braided stent 3 move relatively toward the proximal side, so that the braided stent 3 is pushed out of the delivery sheath 21 and can be released.

[0044] like Figure 4 , Figure 5 , Figure 8 and Fig. 9As shown, a support structure 4 is provided on the inner tube 11, and the support structure 4 is used to support the braided stent 3 to be transported, and the friction between the support structure 4 and the braided stent 3 is greater than the friction between the transport sheath 21 and the braided stent 3. Since the friction between the support structure 4 and the braided stent 3 is greater, when the transport sheath 21 moves toward the distal side, the braided stent 3 will be supported by the support structure 4 and will not easily move with the transport sheath 21, thereby avoiding the problem of stacking of the braided stent 3 during pushing and causing the pushing failure.

[0045] Specifically, the support structure 4 is made of soft materials such as nylon elastomer (pebax4533), thermoplastic polyurethane elastomer (TPU) or silicone, which can increase the friction between the support structure 4 and the braided stent 3; the delivery sheath 21 includes an inner layer structure for contacting the braided stent 3, and the inner layer structure is made of polytetrafluoroethylene, which can reduce the friction between the inner side of the delivery sheath 21 and the braided stent 3. Therefore, the friction between the support structure 4 and the braided stent 3 is greater, and when the delivery sheath 21 moves toward the distal side, the braided stent 3 will not move with it, but will be attached to the inner tube 11, thereby avoiding the phenomenon of stacking.

[0046] Furthermore, if Figure 5 As shown, the support structure 4 is constructed as a thread strip spirally wound on the outer wall of the inner tube 11, and the thread strip can be fixed to the outer wall of the inner tube 11 by an adhesive (such as glue). The thread strip is spirally distributed on the inner tube 11 and contacts the inner side of the braided stent 3 to provide adhesion so that the braided stent 3 is not easy to move with the delivery sheath 21.

[0047] Optionally, the thread strip is wound on the outer wall of the inner tube 11 in the form of a single thread. It can be understood that the thread strip can also be wound on the outer wall of the inner tube 11 in the form of multiple threads.

[0048] Preferably, the thread strip is wound around the outer wall of the inner tube 11 in a double helix form, and the pitch of the thread strip is greater than 1 mm. The double helix thread strip has two supporting points symmetrical about the axis on the same radial section, so it can provide a more uniform supporting force for the braided stent 3, which is conducive to the braided stent 3 to expand and unfold along the expected shape after being pushed.

[0049] When the thread strip is wound on the outer wall of the inner tube 11 in the form of three or more spirals, there are multiple supporting points symmetrical about the axial direction on the same radial cross section.

[0050] If the width of the thread strip is too narrow, it will not play a supporting role, so the width of the thread strip is greater than 0.2 mm, for example, it can be 0.3 mm.

[0051] The thickness of the thread strip is less than (D1-D2) / 2, where D1 is the inner diameter of the outer tube 12 and D2 is the outer diameter of the inner tube 11. In addition, if the thickness of the thread strip is too thin, it will not play a supporting role, so the thickness of the thread strip can be set to be greater than 0.1 mm, for example, 0.2 mm.

[0052] The delivery sheath 21 includes an outer layer structure, an intermediate layer structure and an inner layer structure which are arranged in sequence from the outside to the inside. The outer layer structure can be formed of nylon material, and the intermediate layer structure is a woven mesh structure, which can have high flexibility.

[0053] like Figure 6 and Figure 7 As shown, a guide head 14 is provided at the proximal end of the inner tube 11. The guide head 14 is a conical structure, which plays a role in guiding and reducing resistance when entering the patient's blood vessels or tissues. The guide head 14 is made of thermoplastic polyurethane elastomer, and the outer tube 12 is made of nylon.

[0054] The delivery sheath 21 extends outside the outer tube 12 and extends to abut against the guide head 14. Figure 6 and Figure 7 Please combine Figure 4 The proximal end of the guide head 14 is configured as a tapered end 141, and the distal end thereof is configured as a connector 142 with a slightly smaller diameter. The connector 142 can be inserted into the transport sheath 21, so that the end of the transport sheath 21 can abut against the connection between the tapered end 141 and the connector 142.

[0055] The outer tube 12 is arranged outside the inner tube 11, and the front end side of the inner tube 11 extends out from the outer tube 12, that is, the outer tube 12 only covers the rear end side part of the inner tube 11, and the two can be fixedly connected by an adhesive (such as glue).

[0056] The distal end of the outer tube 12 is connected to a push rod 13, which is made of stainless steel to enhance the strength of the push rod assembly 1. A thin-walled boss may be provided on the push rod 13, which extends into the distal end of the outer tube 12, and the two are fixedly connected by an adhesive (such as glue).

[0057] The distal end of the push rod 13 is connected to a handle seat 15, which is a force-applying part for an operator. When the braided stent 3 is pushed to a designated position, it expands and unfolds by itself, and the braided stent 3 can be released.

[0058] like Fig.10As shown, the sheath tube assembly 2 also includes a Y-shaped valve 23 connected to the delivery outer sheath 21, and the Y-shaped valve 23 fixes the sheath tube assembly 2 on the push rod 13 through a locking cap 231 thereon. The Y-shaped valve 23 is made of polycarbonate (PC), and the locking cap 231 can be integrally formed with the Y-shaped valve 23. The contrast agent can be pushed to the target position through the Y-shaped valve 23, and the contrast agent can be, for example, iodixanol or iopromide.

[0059] After the braided stent 3 is loaded between the delivery sheath 21 and the inner tube 11, the sheath tube assembly 2 can be fixed on the push rod 13 by the locking cap 22. After the delivery system reaches the designated position, the locking cap 22 is released and the delivery sheath 21 can move toward the distal side.

[0060] It should be noted that the delivery system of the braided stent of the present invention can push stents including but not limited to the braided stent 3 described above, and can also push other types of stents. For example, it can also push stents that can withstand axial tension and axial pressure. When pushing such stents, it is particularly advantageous that the delivery system of the braided stent of the present invention can also retract such stents after a part of them are pushed out, thereby adjusting the release position of the stent. Fig.12 , Fig.13 and Fig.14 As shown, the present invention also provides a threaded strip forming device 100 as described above, which comprises a base 110, on which a driving assembly 140 and a cutting assembly 120 are respectively arranged.

[0061] like Fig.13 As shown, the cutting assembly 120 includes a base 122 and a cutting blade 121 disposed above the base 122. The cutting blade 121 may be, for example, a combination of two blades, or a combination of multiple blades.

[0062] The upper end of the base 122 is provided with an inclined groove 123 extending along the height direction thereof, and the angle between the inclined groove 123 and the length direction of the base 122 is determined by the pitch of the support structure 4. The cutting blade 121 is arranged in the inclined groove 123.

[0063] The driving assembly 140 includes a motor 1401, a coupling 1402 connected to the motor 1401, a chuck 1403 connected to the coupling 1402, a spindle 1404 connected to the chuck 1403, and a slider 1405 disposed below the motor 1401. The slider 1405 is disposed on the slide rail 130 on the base 110, thereby driving the driving assembly 140 to slide on the slide rail 130.

[0064] The motor 1401 may be a precision N20 reduction motor, with a suitable voltage of 3V to 6V (36 to 72 revolutions), which is connected to a DC power supply, the voltage of which is adjustable from 3V to 12V, and the speed of the motor 1401 may be adjusted by adjusting the knob of the DC power supply. The coupling 1402 may achieve electrical isolation, for example, a coupling with an outer diameter of 14mm and a length of 22mm may be used.

[0065] The chuck 1403 may be a three-jaw chuck, which is used to clamp the mandrel 1404. The chuck 1403 may clamp the mandrel 1404 with a diameter of 0.3 mm to 3.4 mm. Fig.14 As shown, the mandrel 1404 passes through the upper side of the base 122, and the end of the mandrel 1404 is fixed on the positioning seat 150 on the base 110. The mandrel 1404 and the positioning seat 150 can be clearance fit.

[0066] The core shaft 1404 is provided with a hose 160 to be cut, and the hose 160 can be interference fit with the core shaft 1404, such as Fig.13 and Fig.14 As shown, the hose 160 is placed in the groove 124 on the base 122.

[0067] During cutting, the motor 1401 drives the core shaft 1404 to rotate, so that the hose 160 rotates through the cutting blade 121 and is cut, thereby forming a spiral structure.

[0068] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A delivery system for a braided stent, characterized in that: include: A push rod assembly (1), the push rod assembly (1) comprising an inner tube (11); as well as A sheath tube assembly (2), the sheath tube assembly (2) comprising a delivery outer sheath (21), the delivery outer sheath (21) being arranged outside the inner tube (11), and the space between the delivery outer sheath (21) and the inner tube (11) being used to accommodate a braided stent (3); A support structure (4) is provided on the inner tube (11), and the support structure (4) is used to support the braided stent (3) to be transported. The support structure (4) is constructed so that the friction force between the support structure (4) and the braided stent (3) is greater than the friction force between the transport outer sheath (21) and the braided stent (3).

2. The delivery system of the braided stent according to claim 1, characterized in that: The support structure (4) is made of nylon elastomer, thermoplastic polyurethane elastomer or silicone; the delivery sheath (21) includes an inner layer structure for contacting the braided stent (3), and the inner layer structure is made of polytetrafluoroethylene.

3. The delivery system of the braided stent according to claim 1 or 2, characterized in that: The support structure (4) is configured as a threaded strip spirally wound around the outer wall of the inner tube (11).

4. The delivery system of the braided stent according to claim 3, characterized in that: The thread strip is wound around the outer wall of the inner tube (11) in the form of a double helix, and the pitch of the thread strip is greater than 1 mm.

5. The delivery system of the braided stent according to claim 3, characterized in that: The thread strip is wound around the outer wall of the inner tube (11) in the form of a single thread or multiple threads.

6. The delivery system of the braided stent according to claim 1 or 2, characterized in that: The end of the inner tube (11) is also provided with a conical guide head (14), and the end of the transport outer sheath (21) abuts against the guide head (14).

7. The delivery system of the braided stent according to claim 1 or 2, characterized in that: The push rod assembly (1) further comprises an outer tube (12) covering a portion of the inner tube (11) and a push rod (13) connected to the outer tube (12), wherein the outer tube (12) is made of nylon and the push rod (13) is made of stainless steel.

8. The delivery system of the braided stent according to claim 7, characterized in that: The thickness of the thread strip is less than (D1-D2) / 2, wherein D1 is the inner diameter of the outer tube (12) and D2 is the outer diameter of the inner tube (11).

9. The delivery system of the braided stent according to claim 8, characterized in that: The sheath tube assembly (2) further comprises a Y-shaped valve (23) connected to the transport outer sheath (21); the Y-shaped valve (23) fixes the sheath tube assembly (2) on the push rod (13) via a locking cap (231) thereon.

10. The delivery system of the braided stent according to claim 9, characterized in that: The Y-shaped valve (23) is made of polycarbonate.

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