Delivery auxiliary sheath tube

Abstract

The invention provides a delivery auxiliary sheath tube, and belongs to the technical field of interventional medical instruments. The delivery auxiliary sheath tube comprises a main body catheter and an operating handle arranged at the near end of a catheter main body, the main body catheter is provided with a tube cavity extending in the axial direction, the delivery auxiliary sheath tube further comprises a supporting unit and a control mechanism, and the supporting unit is arranged at the far end of the main body catheter and is configured to have a radial expansion state and a radial contraction state; the control mechanism is arranged on the main body catheter and used for controlling the supporting unit to be switched between the expansion state and the contraction state. When the supporting unit is in the expanded state, the supporting unit is configured to support the far end of the main body catheter in the area, close to the center, of a blood vessel cavity so as to be far away from the blood vessel wall to eliminate step obstacles faced by subsequent instruments extending out of the far end of the catheter cavity; the technical problems that in the prior art, an auxiliary delivery instrument is tedious in operation, cannot be repeatedly used and is poor in self-in-place performance are mainly solved.

Description

Technical Field

[0001] This invention belongs to the field of interventional medical device technology, specifically relating to a delivery auxiliary external sheath. Background Technology

[0002] Occlusion distal to the ophthalmic segment of the internal carotid artery accounts for more than 65% of acute ischemic strokes (MR CLEAN statistics). Successfully reaching the occlusion site using a large-diameter reperfusion catheter that crosses the ophthalmic artery segment is crucial for vascular recanalization. However, anatomical obstacles and the tortuous nature of the vascular pathway—such as the ophthalmic artery's "step-windowsill effect"—make manipulating a large-diameter reperfusion catheter to reach the occlusion site extremely difficult, sometimes even resulting in failure, and carries the risk of damaging the vessel wall, leading to vascular dissection and subarachnoid hemorrhage.

[0003] One crucial aspect is how the aspiration catheter overcomes the "step-windowsill effect" of the ophthalmic artery. The aspiration catheter is typically delivered to the target location under the guidance of a guidewire. However, in cases of tortuous siphon pathways, the "tip" of the aspiration catheter often becomes stuck at the origin of the internal carotid artery and / or the ophthalmic artery (please refer to...). Figure 1 This makes it difficult for the suction catheter to be properly positioned.

[0004] To overcome the "windowsill effect" and assist in the placement of the aspiration catheter, existing technologies typically use dedicated intermediate or delivery catheters. These catheters, through their specific outer diameter design, match the inner lumen of the aspiration catheter to eliminate radial dimensional differences between the guidewire and the aspiration catheter, providing a smooth transition channel for the aspiration catheter. However, this approach has the following technical problems in practical use: First, this intermediate catheter has a single function, used only when the target catheter is in place. After the aspiration catheter is in place, it needs to be withdrawn from the lumen of the aspiration catheter to avoid affecting the aspiration effect. If the aspiration catheter needs to be readjusted or repeatedly inserted and removed, the intermediate catheter must also be repeatedly inserted and removed, which greatly increases the number of operation steps and delays valuable recanalization time.

[0005] Secondly, many intermediate catheters have high overall rigidity to provide sufficient support for the inner diameter of the aspiration catheter, resulting in insufficient flexibility. This makes it difficult to pass through more proximal tortuous blood vessels and reach the ideal auxiliary position.

[0006] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0007] The purpose of this invention is to provide a delivery auxiliary outer sheath to solve the technical problems of existing auxiliary delivery devices, such as cumbersome operation, inability to be reused, and poor self-positioning.

[0008] To achieve the above objectives, the delivery-assisted outer sheath of the present invention provides the following technical solution: A delivery assistance outer sheath includes a main catheter and an operating handle disposed proximal to the main catheter body, the main catheter having an axially extending lumen, and further includes: A support unit is disposed at the distal end of the main conduit, and the support unit is configured to have a radially expanded state and a contracted state. A control mechanism, which is mounted on the main guide tube, is used to control the support unit to switch between an expanded state and a contracted state. When the support unit is in the expanded state, it is configured to support the distal end of the main catheter in a region near the center of the blood vessel lumen, away from the blood vessel wall, to eliminate step obstacles faced by subsequent instruments extending from the distal end of the lumen.

[0009] As a further optimized technical solution, the control mechanism includes a sliding component that slides along the axial direction of the main conduit. The sliding component is connected to the proximal end of the support unit via a connector. The sliding component is configured to pull or release the support unit by sliding along its axial direction, so that the support unit switches between a contracted state and an expanded state.

[0010] As a further optimized technical solution, the support unit is an expandable mesh support structure, with its distal end fixedly connected to the outer wall of the main conduit, and its proximal end moving towards or away from the distal end to control the degree of expansion of the support unit.

[0011] As a further optimized technical solution, the connector is a tubular component that is slidably sleeved on the outside of the main conduit.

[0012] As a further optimized technical solution, the sliding component includes: A push button, one end of which protrudes from the side wall of the tubular component, and the other end is located between the tubular component and the main conduit, and has a first limiting part facing the main conduit; A second limiting part is provided on the outer wall of the main conduit and cooperates with the first limiting part; The first limiting part and the second limiting part cooperate to limit the sliding distance of the tubular component.

[0013] As a further optimized technical solution, the first limiting part is a toothed structure with a triangular cross-section, and the second limiting part is adapted to the first limiting part.

[0014] As a further optimized technical solution, a spring-shaped buffer component is provided between the connector and the support unit.

[0015] As a further optimized technical solution, the support unit is an elastic bladder disposed on the outer wall of the main catheter, and the control mechanism is an inflatable channel arranged along the main catheter.

[0016] As a further optimized technical solution, the mesh support includes support arms spaced apart along the circumference of the main catheter, the support arms extending axially, the distal end of the support arm being fixedly connected to the catheter body, and the proximal end slidingly engaging with the catheter body.

[0017] As a further optimized technical solution, a developing element is provided on the support arm.

[0018] Beneficial effects: This invention, by setting a support unit on the outer wall of the outer sheath, can support the distal end of the main catheter in the area near the center of the blood vessel lumen when the support unit expands, away from the blood vessel wall. This avoids the subsequent instruments (such as aspiration catheters) from being stuck due to the step effect of the blood vessel wall when extending from the distal end of the outer sheath, significantly improving the efficiency of subsequent instrument placement. It is especially suitable for anatomical sites with a "windowsill effect," such as the ophthalmic segment of the internal carotid artery. At the same time, the expansion and contraction states of the support unit can be flexibly switched through the control mechanism, eliminating the need for repeated insertion and removal of the outer sheath. When the aspiration catheter needs to be adjusted or repeatedly inserted and removed, only the state of the support unit needs to be controlled, greatly simplifying the operation steps, saving recanalization time, and reducing the difficulty of the surgery. In addition, this outer sheath is sleeved on the outside of the aspiration catheter and does not occupy the inner lumen space of the aspiration catheter. Therefore, it does not affect the aspiration function of the aspiration catheter. When the aspiration catheter needs to be adjusted or repeatedly inserted and removed, only the state of the support unit needs to be controlled, eliminating the need to repeatedly insert and remove the outer sheath along with the aspiration catheter, greatly simplifying the operation steps, saving recanalization time, and reducing the difficulty of the surgery. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein: Figure 1 A schematic diagram of the "windowsill effect" at the ophthalmic artery; Figure 2 This is a schematic diagram of a working state of Embodiment 1 of the delivery auxiliary outer sheath of the present invention; Figure 3 This is a schematic diagram of another working state of Embodiment 1 of the delivery auxiliary outer sheath of the present invention; Figure 4 This is a schematic diagram of the push button structure in Embodiment 1 of the delivery auxiliary outer sheath of the present invention; Figure 5 This is a schematic diagram of the structure of embodiment 2 of the delivery auxiliary outer sheath of the present invention.

[0020] In the figure: 100, main conduit; 200, operating handle; 210, outer stress diffusion tube; 220, inner stress tube; 300, support unit; 400, control mechanism; 410, sliding component; 411, push button; 412, first limiting part; 413, second limiting part; 420, connector; 430, buffer component; 440, developing component. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0022] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. Furthermore, the term "proximal end" uniformly refers to the end closer to the operator, while "distal end" refers to the end farther from the operator.

[0023] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0024] The shapes and sizes of the components in the accompanying drawings do not reflect the actual proportions of the product; they are only intended to illustrate the content of the invention.

[0025] This invention provides a delivery-assisted external sheath, primarily addressing the technical problems of existing delivery-assisted devices, such as cumbersome operation, lack of reusability, poor self-positioning, and interference with aspiration function. The external sheath includes a main catheter 100, an operating handle 200, a support unit 300, and a control mechanism 400. The main catheter 100 has an axially extending lumen. The support unit 300 is located at the distal end of the main catheter 100 and can switch between radial expansion and contraction states. The control mechanism 400 is used to regulate the state of the support unit. When the support unit 300 expands, it supports the distal end of the main catheter 100 near the central region of the blood vessel lumen, eliminating step obstacles faced by subsequent devices (such as aspiration catheters). This invention is fitted onto the outside of the aspiration catheter without affecting its aspiration function. Adjusting the position of the aspiration catheter eliminates the need for repeated insertion and withdrawal, simplifying the operation, saving recanalization time, and effectively reducing the risk of complications such as vascular injury. It is suitable for interventional procedures in complex anatomical locations such as the ophthalmic segment of the internal carotid artery.

[0026] Example 1 like Figure 2 , Figure 3 As shown, the delivery auxiliary outer sheath includes a main catheter 100, an operating handle 200, a support unit 300, and a control mechanism 400.

[0027] The operating handle 200 is located at the proximal end of the main conduit 100, making it easy for the operator to hold and adjust the working state of the main conduit 100.

[0028] The main catheter 100 has an axially extending lumen, and its wall is composed of a multi-layered composite structure, comprising, from the inside out, an inner liner, a central reinforcing layer, and an outer protective layer. The inner liner is made of polytetrafluoroethylene (PTFE), with a smooth inner lumen and a low coefficient of friction, facilitating the smooth passage of instruments (especially aspiration catheters). The central reinforcing layer is made of braided or wound-braided metal (stainless steel or nickel-titanium alloy) to enhance the pushing force and flexural strength of the main catheter 100 while maintaining its flexibility. The outer protective layer is made of polymer materials such as polyurethane, nylon, or polyether block amide (PEBAX), providing the main catheter 100 with kink resistance and mechanical protection.

[0029] The support unit 300 is located at the distal end of the main catheter 100 and is an expandable mesh stent structure cut from nickel-titanium alloy shape memory alloy tubing. Nickel-titanium alloy possesses excellent biocompatibility and shape memory properties, allowing it to stably maintain its set shape at body temperature. Specifically, the mesh stent includes six support arms evenly spaced along the circumference of the main catheter 100. These support arms extend axially along the main catheter 100, with the distal ends fixedly connected to the outer wall of the main catheter 100 via laser welding. The proximal ends of the support arms are connected to the control mechanism 400, allowing the support unit 300 to expand and contract by moving the proximal ends towards or away from the distal ends. Each support arm is embedded with a contrast agent 440, made of platinum-iridium alloy, which can be clearly visualized under DSA (digital subtraction angiography) equipment, facilitating real-time observation of the position and expansion status of the support unit 300 by the operator.

[0030] The control mechanism 400 includes a sliding component 410 and a connector 420. The connector 420 is a tubular component that slides around the outside of the main catheter 100. It is made of metal, specifically a nickel-titanium alloy or stainless steel, and has good force transmission properties. Its distal end is fixedly connected to the proximal end of the support unit 300, extending to a position near the operating handle 200. A spring-shaped buffer component 430 is also provided between the connector 420 and the support unit 300. The buffer component 430 is made of medical-grade stainless steel spring. By using the buffer component 430, the deformation speed of the support unit 300 is delayed, avoiding rigid impact on the blood vessel wall, thereby improving safety during use.

[0031] like Figure 3 , Figure 4As shown, the sliding component 410 includes a push button 411 and a second limiting part 413. One end of the push button 411 extends through a through hole in the side wall of the connector 420, and the other end is located between the connector 420 and the main guide tube 100. By driving the push button 411 to move axially, the connector 420 can be moved axially. The end of the push button 411 located inside the connector 420 has a first limiting part 412 integrally formed facing the main guide tube 100. The first limiting part 412 has a toothed structure with a triangular cross-section. The second limiting part 413 is disposed on the outer wall of the main conduit 100 and extends along the axial direction of the main conduit 100. The second limiting part 413 is a toothed groove adapted to the first limiting part 412. The toothed structures of the first limiting part 412 and the second limiting part 413 mesh with each other to achieve the limiting function, restricting the sliding distance of the connector 420 and avoiding excessive pulling or releasing of the support unit 300. Specifically, during movement, the operator pushes the button forcefully, causing the first limiting part 412 and the second limiting part 413 to undergo elastic deformation to generate relative displacement. In this embodiment, the second limiting part 413 is disposed on the operating handle 200 on the outer side of the main conduit 100. In other embodiments, it can also be directly disposed on the outer wall of the main conduit 100.

[0032] In practical use, during intracranial delivery, the sliding component 410 is positioned proximally. The connector 420 and buffer component 430 pull the proximal end of the support unit 300 proximally, causing the mesh stent to be axially stretched and radially compressed, tightly fitting against the outer wall of the main catheter 100, maintaining a minimum outer diameter. At this time, the outer sheath moves along the guidewire to the target position. When the sheath reaches the target tortuous area (such as the "windowsill" at the origin of the ophthalmic artery), it is observed under fluoroscopy. The sliding component 410 is then pushed forward (distally). The connector 420 moves forward accordingly, releasing the pulling force on the proximal end of the support unit 300. The superelasticity of the nickel-titanium alloy allows it to regain its shape memory, and the mesh stent expands radially. During the pushing process, the engagement of the first limiting part 412 and the second limiting part 413 provides a clear stopping sensation, limiting the maximum expansion stroke and preventing over-expansion. The expanded support unit 300 presses against the vessel wall, lifting the distal end of the main catheter 100 so that its opening is no longer attached to the vessel wall and is in a relatively suspended position. At this time, the distal end of the main catheter 100 is located in the region near the center of the vessel lumen (because the support unit 300 cannot be guaranteed to expand absolutely uniformly, it cannot be guaranteed that the distal end of the main catheter 100 is located in the absolutely central region of the vessel, thus the distal end of the main catheter 100 is located in the region near the center of the vessel lumen). At this time, the aspiration catheter can smoothly extend from the distal end through the lumen of the main catheter 100. Since there is no "step" formed by the vessel wall blocking its exit, the aspiration catheter can smoothly enter the vessel lumen and continue to advance towards the distal occlusion. If the position of the aspiration catheter needs to be adjusted, simply pull the sliding component 410 back to the proximal end, which will cause the support unit 300 to re-contract. After the sheath position is adjusted, it can expand again to provide support. Furthermore, the expansion degree of the support unit 300 can be adjusted by adjusting the moving distance of the sliding component 410 to adapt to the stepped structure at different positions, while the spring-shaped buffer component 430 can effectively relieve stress during operation.

[0033] Example 2 like Figure 5 As shown, the main difference between this embodiment and Embodiment 1 lies in the different structures of the support unit 300 and the control mechanism 400; the remaining structures are basically the same as in Embodiment 1. Specifically, in this embodiment, the operating handle 200 includes an outer stress diffusion tube 210 and an inner stress tube 220. The outer stress diffusion tube 210 and the inner stress tube 220 are composed of stainless steel, polyether block amide (PEBAX), polyolefin, polyurethane (PU), and thermoplastic elastomer (TPE), forming a stepped structure that is heat-shrinkably bonded to the proximal end of the main conduit 100 to reduce stress concentration and prevent the conduit from kinking or breaking.

[0034] The support unit 300 is an elastic bladder disposed on the outer wall of the main catheter 100. The elastic bladder is made of medical-grade silicone rubber and is bonded and fixed to the distal outer wall of the main catheter 100, forming a closed cavity. Both ends of the elastic bladder are equipped with radiopaque rings as radiopaque elements 440. The control mechanism 400 is an inflation channel arranged along the inner wall of the main catheter 100. The distal end of the inflation channel communicates with the cavity of the elastic bladder, and the proximal end extends to the operating handle 200 and is connected to a Luer connector. The Luer connector connects to the inflation channel to extract or fill gas or liquid within the elastic bladder, controlling the operating state of the support unit 300.

[0035] In practice, the elastic capsule is first attached to the main catheter 100 so that it is in a contracted state. Then, the main catheter 100 is moved along the guide wire until the distal end of the main catheter 100 is advanced to the target position, and the position is confirmed by DSA imaging equipment.

[0036] Then, a filling medium such as saline or medical gas is injected into the filling channel through the Luer connector. The filling medium enters the elastic bladder, causing it to expand in real time, supporting the distal end of the main catheter 100 in the region near the center of the blood vessel lumen (because the support unit 300 cannot be guaranteed to expand absolutely uniformly, it cannot be guaranteed that the distal end of the main catheter 100 is located in the absolutely central region of the blood vessel, thus placing the distal end of the main catheter 100 in the region near the center of the blood vessel lumen). During the filling process, the degree of expansion of the elastic bladder can be adjusted by the amount of filling medium injected to suit the specific blood vessel diameter and avoid over-expansion and compression of the blood vessel. Afterwards, the aspiration catheter is advanced along the lumen of the outer sheath to the target position. Because the outer sheath is placed outside the aspiration catheter, it does not occupy its inner space and will not affect the aspiration function of the aspiration catheter. After the delivery of the aspiration catheter and the surgical operation are completed, if it is necessary to adjust the position of the aspiration catheter, the aspiration catheter can be moved directly without repeatedly inserting and removing the outer sheath. After the adjustment is completed or the operation is completed, the filling medium in the elastic capsule is withdrawn through the Luer connector, the support unit 300 contracts, and the outer sheath is withdrawn.

[0037] In summary, the delivery assistance sheath provided by this invention, through the cooperation of the support unit and the control mechanism, can effectively enable the aspiration catheter to overcome step obstacles within blood vessels. At the same time, its design of being sleeved on the outside of the aspiration catheter does not affect the aspiration function, and there is no need to repeatedly insert and withdraw it when adjusting the position, which simplifies the operation steps, improves surgical efficiency and safety, reduces medical costs, and is suitable for interventional surgery in complex anatomical locations such as the ophthalmic segment of the internal carotid artery.

[0038] It is understood that the above description is merely exemplary and the embodiments of this application do not limit the scope of the application.

[0039] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are within the protection scope of the present invention.

Claims

1. A delivery assistance outer sheath, comprising a main catheter (100) and an operating handle (200) disposed proximal to the main catheter body, said main catheter (100) having an axially extending lumen, characterized in that, Also includes: A support unit (300) is disposed at the distal end of the main conduit (100), and the support unit (300) is configured to have a radially expanded state and a contracted state; A control mechanism (400) is provided on the main conduit (100) for controlling the support unit (300) to switch between an expanded state and a contracted state; When the support unit (300) is in the expanded state, it is configured to support the distal end of the main catheter (100) in a region near the center of the vascular lumen, away from the vascular wall, to eliminate step obstacles faced by subsequent instruments extending from the distal end of the lumen.

2. The delivery auxiliary outer sheath according to claim 1, characterized in that, The control mechanism (400) includes a sliding member (410) that slides axially along the main conduit (100), the sliding member (410) being connected to the proximal end of the support unit (300) via a connector (420); the sliding member (410) is configured to pull or release the support unit (300) by sliding axially to switch the support unit (300) between a contracted state and an expanded state.

3. The delivery auxiliary outer sheath according to claim 1, characterized in that, The support unit (300) is an expandable mesh support structure. Its distal end is fixedly connected to the outer wall of the main conduit (100), and its proximal end moves toward or away from the distal end to control the degree of expansion of the support unit (300).

4. The delivery auxiliary outer sheath according to claim 2, characterized in that, The connector (420) is a tubular component that is slidably sleeved on the outside of the main conduit (100).

5. The delivery auxiliary outer sheath according to claim 4, characterized in that, The sliding component (410) includes: Push button (411), one end of which protrudes through the side wall of the tubular component, and the other end is located between the tubular component and the main conduit (100), and has a first limiting part (412) provided toward the main conduit (100). A second limiting part (413) is provided on the outer wall of the main conduit (100) and cooperates with the first limiting part (412); The first limiting part (412) and the second limiting part (413) cooperate to limit the sliding distance of the tubular component.

6. The delivery auxiliary outer sheath according to claim 5, characterized in that, The first limiting part (412) is a toothed structure with a triangular cross-section, and the second limiting part (413) is adapted to the first limiting part (412).

7. The delivery auxiliary outer sheath according to claim 2, 4, 5, or 6, characterized in that, A spring-shaped buffer component (430) is provided between the connector (420) and the support unit (300).

8. The delivery auxiliary outer sheath according to claim 1, characterized in that, The support unit (300) is an elastic bladder disposed on the outer wall of the main conduit (100), and the control mechanism (400) is a filling channel arranged along the main conduit (100).

9. The delivery auxiliary outer sheath according to claim 3, characterized in that, The mesh support includes support arms spaced circumferentially along the main conduit (100), the support arms extend axially, the distal end of the support arm is fixedly connected to the conduit body, and the proximal end is slidably engaged with the main conduit (100).

10. The delivery auxiliary outer sheath according to claim 9, characterized in that, The support arm is provided with a developing element (440).

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