Conveying sheath tube with flexibility and pushing performance

Abstract

The invention relates to the field of medical instruments, in particular to a conveying sheath tube with both flexibility and pushing performance, which comprises an inner membrane layer, a reinforcing layer and an outer layer which are sequentially arranged from inside to outside, and the inner membrane layer and the outer layer are tube layers made of high polymer materials; the reinforcing layer comprises a plurality of latticed pipe bodies which are arranged in the axial direction, and each latticed pipe body comprises a plurality of chain link units which are sequentially connected side by side in the circumferential direction; the far end of each chain link unit is provided with a spherical connector, the near end of each chain link unit is provided with a pivot joint groove matched with the spherical connector, and every two axially adjacent chain link units are movably connected in the mode that the spherical connector of one chain link unit is rotatably meshed with the pivot joint groove of the other chain link unit. The reinforcing layer can realize bending deflection and transmit pushing force in the axial direction at the same time; according to the scheme, the spherical connector is creatively used for being matched with the pivoting groove, so that the conveying sheathing canal can be well pushed in a bent state, and bending of the conveying sheathing canal is avoided.

Description

Technical Field

[0001] This application belongs to the field of medical devices, specifically relating to a delivery sheath that combines flexibility and delivery performance. Background Technology

[0002] In minimally invasive surgeries such as vascular and neurointerventional procedures, delivery sheaths are crucial instruments used to deliver therapeutic devices such as stents, coils, and filters to complex target locations within the body. An ideal delivery sheath needs to simultaneously satisfy two seemingly contradictory properties: on the one hand, in order to traverse tortuous and narrow physiological and anatomical pathways (such as intracranial blood vessels), the distal portion of the sheath must possess extremely high flexibility, conforming to the natural curvature of the blood vessels without damage; on the other hand, in order to accurately push the device to the target location, the sheath body needs sufficient pushing force transmission performance (i.e., "pushing capability") to avoid energy dissipation, tube bending, or loss of control during long-distance delivery.

[0003] To resolve this contradiction, a common approach in the prior art is to use a metallic material in the middle reinforcing layer of the sheath and design it to be composed of multiple axially arranged sheet-like or annular small units that are interlocked and connected. For example, patent application CN201911300548.7 discloses a delivery sheath and a medical device. The delivery sheath includes a tube body and a support member disposed in the tube body. The support member includes multiple hollow sub-components spliced ​​end to end. The proximal end of each hollow sub-component includes multiple proximal protrusions distributed along the circumference of the hollow sub-component, and a proximal groove is formed between two adjacent proximal protrusions. The distal end of each hollow sub-component includes multiple distal protrusions distributed along the circumference of the hollow sub-component, and a distal groove is formed between two adjacent distal protrusions. The number of proximal protrusions of the hollow sub-component is equal to the number of distal protrusions of the same hollow sub-component. A distal groove on a hollow sub-component is aligned with a proximal protrusion on the same hollow sub-component. Multiple proximal protrusions on one hollow sub-component engage with multiple distal grooves of another hollow sub-component. While this patented solution utilizes the interplay of protrusions and grooves to provide good axial pushing force, the sheet-like protrusions and grooves can misalign when the delivery sheath is bent. If the delivery sheath needs to be pushed at this time (i.e., pushed while in a bent state), the contact surfaces between the sheet-like units will slide or tilt relative to each other. Since these contact surfaces are typically planar or have sharply defined edges, stress concentration is easily generated under bending stress, potentially leading to unintended misalignment or locking of adjacent units. This misalignment not only drastically increases local bending stiffness, making the operation feel harsh, but also, during repeated bending or sharp bends, structural instability can cause irreversible bending or twisting of the sheath, resulting in surgical failure or even vascular damage.

[0004] In summary, while existing delivery sheaths offer good pushing performance, continued pushing during bending can lead to sheath breakage. There is an urgent clinical need for a novel delivery sheath that balances flexibility and pushing performance, minimizing stress and enabling flexible steering during bending, while simultaneously providing an immediate and rigid transmission of axial thrust during pushing. Summary of the Invention

[0005] This application is made in view of the above and other ideas.

[0006] One of the purposes of this application is to overcome the shortcomings of the prior art, such as the problem that the delivery sheath is prone to bending when it continues to be pushed while bent in the prior art, and to provide a delivery sheath that takes into account both flexibility and pushing performance.

[0007] The technical solution adopted to solve the technical problem of the present invention is to provide a delivery sheath that takes into account both flexibility and pushing performance, including an inner membrane layer, a reinforcing layer and an outer layer arranged sequentially from the inside to the outside. The inner membrane layer and the outer layer are tubular layers made of polymer material. The reinforcing layer includes a plurality of axially arranged grid-like tubes, each grid-like tube including a plurality of chain link units connected in parallel in a circumferential direction. Each chain link unit has a spherical connector at its distal end and a pivot groove adapted to the spherical connector at its proximal end. Two axially adjacent chain link units are rotatably engaged with the pivot groove of the other through the spherical connector of one to form a movable connection, so that the reinforcing layer can transmit pushing force in the axial direction while bending and deflecting.

[0008] As a further improvement of the present invention, the ball head of the spherical connector is part of a sphere or an ellipsoid.

[0009] As a further improvement of the present invention, the pivot groove is a ball-and-socket groove or a partially spherical groove, the outline of which matches the surface of the spherical connector.

[0010] As a further improvement of the present invention, the inlet of the pivot groove is provided with a tapering structure, the size of which is smaller than the maximum diameter of the spherical connector, so as to prevent the adjacent link units from axially disengaging.

[0011] As a further improvement of the present invention, when the delivery sheath is bent, the spherical connector slides or rolls within the pivot groove, and the spherical connector always abuts against the pivot groove.

[0012] As a further improvement of the present invention, when the delivery sheath is subjected to axial pushing force, the spherical connector abuts against the axial force bearing surface of the pivot groove.

[0013] As a further improvement of the present invention, in at least a portion of the link unit, a connecting portion for guiding deflection and dispersing stress is provided between the spherical connector and the pivot groove; the longitudinal cross-sectional profile of the connecting portion is V-shaped, wavy, or arc-shaped.

[0014] As a further improvement of the present invention, the diameter of the spherical connector is greater than the wall thickness of the pipe wall in the region where the pivot groove is located on the chain link unit.

[0015] As a further improvement of the present invention, the reinforcing layer is made of nickel-titanium alloy or stainless steel.

[0016] As a further improvement of the present invention, the polymer material is selected from one or more combinations of polytetrafluoroethylene, high-density polyethylene, polyether block amide, or thermoplastic polyurethane.

[0017] According to a concept of this application, adjacent link units are connected by a ball joint and a ball socket in the pivot groove. This structure essentially constitutes a "flexible directional joint". When the sheath bends, the ball joint can slide and roll in multiple directions within the pivot groove, enabling smooth, low-friction pivoting between adjacent units. Compared to the planar sliding of a plate-like snap-fit, this point-to-surface contact rolling friction resistance is extremely small, thereby significantly reducing the stress required for bending. This allows the distal end of the sheath to pass through tortuous anatomical paths extremely smoothly. Furthermore, when the sheath bends, the ball joint always abuts against the pivot groove, ensuring that its reinforcing layer maintains good pushing performance. This balances the ability of the transport sheath to bend smoothly and maintain good pushing capability even when bent.

[0018] The embodiments of this application can achieve other advantageous technical effects not listed one by one. These other technical effects may be partially described below and can be expected and understood by those skilled in the art after reading this application. Attached Figure Description

[0019] The above-described features and advantages of these embodiments, as well as other features and advantages, and the ways in which they are implemented, will become more apparent and the embodiments of this application will be better understood by referring to the following description in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram of the overall delivery sheath of the present invention.

[0020] Figure 2 , Figure 3 , Figure 4 This is a schematic diagram of the mesh-like tube body and its detailed structure according to the present invention.

[0021] The features represented by the numbers in the attached diagram are as follows: 1-Inner membrane layer, 2-Reinforcing layer, 21-Grid-like tube body, 22-Chain link unit, 23-Spherical connector, 24-Pivot groove, 25-Closing structure, 26-Connecting part, 3-Outer layer. Detailed Implementation

[0022] The details of one or more embodiments of this application will be set forth in the following description of the accompanying drawings and specific embodiments. Other features, objects, and advantages of this application will become clear from these descriptions, drawings, and claims.

[0023] It should be understood that the illustrated and described embodiments are not limited in application to the details of the construction and arrangement of the components set forth in the following description or illustrated in the accompanying drawings. The illustrated embodiments may be other embodiments and can be implemented or performed in various ways. The examples are provided by way of explanation rather than limitation of the disclosed embodiments. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of this application without departing from the scope or spirit of this disclosure. For example, features illustrated or described as part of one embodiment may be used with another embodiment to still produce another embodiment. Therefore, this disclosure covers such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0024] Similarly, it is understood that the phrases and terms used in this document are for descriptive purposes and should not be considered restrictive. The use of “including,” “contains,” or “has,” and their variations, in this document is intended to include, in an open-ended manner, the items listed thereafter, their equivalents, and any additional items.

[0025] The present application will now be described in more detail with reference to various embodiments and examples of several aspects thereof.

[0026] One of the objectives of the embodiments described below is to address the aforementioned deficiencies, as well as other problems.

[0027] Example 1: A delivery sheath that balances flexibility and pushing performance, such as Figure 1 , Figure 2 , Figure 3 , Figure 4As shown, the structure includes an inner membrane layer 1, a reinforcing layer 2, and an outer layer 3 arranged sequentially from the inside out. The inner membrane layer 1 and the outer layer 3 are tubular layers made of polymer materials. The reinforcing layer 2 includes a plurality of axially arranged grid-like tubes 21, each grid-like tube 21 including a plurality of circumferentially connected link units 22. Each link unit 22 has a spherical connector 23 at its distal end and a pivot groove 24 adapted to the spherical connector 23 at its proximal end. Two axially adjacent link units 22 can be rotatably engaged with the pivot groove 24 of the other through the spherical connector 23 of one to form a movable connection, so that the reinforcing layer 2 can transmit pushing force in the axial direction while bending and deflecting.

[0028] In this embodiment, when the delivery sheath is bent, the spherical connector 23 slides into the pivot groove 24 to maintain the flexibility of the delivery sheath. Furthermore, even when bent, the spherical connector 23 and the pivot groove 24 remain in contact. If the delivery sheath needs to be pushed at this time, the spherical connector 23 presses against the pivot groove 24 to transmit the pushing force, so that the delivery sheath can maintain both flexibility and good pushing performance.

[0029] In this embodiment, the ball head of the spherical connector 23 is part of a sphere or an ellipsoid.

[0030] In this embodiment, the inner surface of the inner membrane layer 1 is smooth to form a low-friction instrument delivery channel, effectively reducing the resistance of the treatment device (such as a coil or stent) during the pushing process.

[0031] In this embodiment, the outer layer is made of thermoplastic polyurethane (TPU) material and is tightly wrapped around the reinforcing layer 2 by heat shrinking or co-extrusion coating process; the outer layer encloses and fixes the link unit 22, while providing a blood biocompatible outer surface and additional structural integrity.

[0032] In this embodiment, the pivot groove 24 is a ball-and-socket groove or a partially spherical groove, the outline of which matches the surface of the spherical connector 23.

[0033] In this embodiment, a tapering structure 25 is provided at the entrance of the pivot groove 24. The size of the tapering structure 25 is smaller than the maximum diameter of the spherical connector 23 to prevent the adjacent link unit 22 from axially disengaging.

[0034] In this embodiment, when the delivery sheath is bent, the spherical connector 23 slides or rolls within the pivot groove 24, and the spherical connector 23 always abuts against the pivot groove 24.

[0035] In this embodiment, when the delivery sheath is subjected to axial pushing force, the spherical connector 23 abuts against the axial force bearing surface of the pivot groove 24.

[0036] In this embodiment, in at least a portion of the link unit 22, a connecting portion 26 for guiding deflection and dispersing stress is provided between the spherical connector 23 and the pivot groove 24; the longitudinal cross-sectional profile of the connecting portion 26 is V-shaped; when the sheath bends, the V-shaped connecting portion 26 provides clear guidance and greater room for movement for the deflection of adjacent link units 22; its two inclined surfaces can smoothly disperse bending stress to a wider tube wall area, significantly avoiding stress concentration at the root of the connection point, thereby greatly enhancing fatigue resistance and bending resistance.

[0037] In this embodiment, the diameter of the spherical connector 23 is greater than the wall thickness of the pipe wall in the region where the pivot groove 24 is located on the link unit 22. The purpose of this design is that, regardless of whether the delivery sheath is being pushed or bent, or being pushed while bent, the spherical connector 23 and the pivot groove 24 can always abut against each other, so as to avoid misalignment between the spherical connector 23 and the pivot groove 24, which would cause the delivery sheath to bend.

[0038] In this embodiment, the reinforcing layer 2 is made of nickel-titanium alloy or stainless steel.

[0039] In this embodiment, the polymer material is selected from one or more combinations of polytetrafluoroethylene, high-density polyethylene, polyether block amide, or thermoplastic polyurethane.

[0040] The foregoing description of the embodiments described above is provided for illustrative purposes. This foregoing description is not intended to be exhaustive, nor is it intended to limit the application to the precise configurations, constructions, and / or steps disclosed. Clearly, many modifications and variations can be made in light of the teachings above. The scope of the invention and all its equivalents are intended to be defined by the appended claims.

Claims

1. A delivery sheath that balances compliance and pushability, comprising, in order from inner to outer, an inner film layer, a reinforcing layer, and an outer layer, characterized in that: The inner membrane layer and the outer layer are tubular layers made of polymer materials; the reinforcing layer includes a plurality of axially arranged grid-like tubes, each grid-like tube comprising a plurality of circumferentially connected link units; wherein, each link unit has a spherical connector at its distal end and a pivot groove adapted to the spherical connector at its proximal end, and two axially adjacent link units are rotatably engaged with the pivot groove of the other through the spherical connector of one to form a movable connection, so that the reinforcing layer can transmit pushing force in the axial direction while bending and deflecting.

2. The delivery sheath of claim 1, wherein: The spherical connector has a spherical head that is part of a sphere or ellipsoid.

3. The delivery sheath of claim 2, wherein: The pivot groove is a ball-and-socket groove or a partially spherical groove, the outline of which matches the surface of the spherical connector.

4. The delivery sheath of claim 1, wherein: The inlet of the pivot groove is provided with a tapering structure, the size of which is smaller than the maximum diameter of the spherical connector, to prevent adjacent link units from axially disengaging.

5. The delivery sheath of claim 1, wherein: When the delivery sheath is bent, the spherical connector slides or rolls within the pivot groove, and the spherical connector always abuts against the pivot groove.

6. The delivery sheath of claim 1, wherein: When the delivery sheath is subjected to axial pushing force, the spherical connector abuts against the axial force bearing surface of the pivot groove.

7. The delivery sheath of claim 1, wherein: In at least some of the link units, a connecting portion for guiding deflection and dispersing stress is provided between the spherical connector and the pivot groove; the longitudinal cross-sectional profile of the connecting portion is V-shaped, wavy, or arc-shaped.

8. The delivery sheath of claim 1, wherein: The diameter of the spherical connector is greater than the wall thickness of the pipe wall in the region where the pivot groove is located on the chain link unit.

9. The delivery sheath of claim 1, wherein: The reinforcing layer is made of nickel-titanium alloy or stainless steel.

10. A delivery sheath that combines flexibility and pushing performance according to claim 1, characterized in that: The polymer material is selected from one or more combinations of polytetrafluoroethylene, high-density polyethylene, polyether block amide, or thermoplastic polyurethane.

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