branch sheath

Abstract

This invention provides a branch sheath, comprising: a covered cannula, a first connecting tube, a control wire, and a restraint coil. The covered cannula has several drainage holes on its wall to mitigate the impact of blood flow resistance on the delivery and positioning of the branch stent during stent introduction and release, while also reducing complications caused by poor blood flow. The covered cannula is located distal to the first connecting tube; the control wire passes through the first connecting tube, with its distal end located within the covered cannula; the proximal end of the restraint coil is connected to the distal end of the first connecting tube, and the distal end of the restraint coil passes through and extends out of the bare end opening of the branch stent; the portion of the control wire passing through the bare end opening of the restraint coil pulls and fixes the bare end of the branch stent, thereby allowing the branch stent to be pulled back into the branch vessel at any time after it has detached from its predetermined position during the procedure, preventing displacement of the branch stent due to the pull of the main stent, and achieving precise control of the release position.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a branch sheath. Background Technology

[0002] With the development of endovascular devices and minimally invasive interventional therapy, endovascular stenting has become a common treatment for aneurysm vascular diseases. The principle is to use a special delivery system to deliver a covered stent to the lesion site and then open it up to isolate the aneurysm, rupture or dissection from the blood, thus avoiding the risk of death caused by aneurysm rupture or dissection expansion and bleeding.

[0003] While minimally invasive stent grafting offers the advantage of less trauma compared to open-chest surgery, it also presents some challenges, particularly regarding the management of branch vessels. Currently, the Castor stent employs an integrated design of the branch stent and the main stent. Before implantation of the main stent, a guiding catheter and guidewire are inserted via a branch vessel in the upper limb. The guidewire from the branch sheath can then smoothly enter the branch vessel through this guiding channel, eliminating the need to select a branch vessel after the main stent has entered the vessel. However, this integrated design can lead to the branch stent being pulled along by the main stent, causing branch stent displacement. During the main stent deployment process, a corresponding branch stent guiding channel is established, and after the main delivery device is withdrawn, the branch stent is implanted. During this process, the main stent has lost the support of the main delivery device and requires an additional fixation point to prevent displacement during branch stent deployment. Simultaneously, the integrated branch stent also requires traction to prevent displacement into the aortic lumen.

[0004] Furthermore, during stent placement and deployment, the stent delivery device inevitably comes into contact with the deployed main stent, especially in the highly curved aortic arch, where the conical head of the delivery device may scrape against the main stent. The friction of the stent itself is insufficient to ensure its fixation to the vessel wall. If the main stent is moved, the positioning of the branch stent may be inaccurate. Stent movement can also damage the vessel wall, and may even cause the branch stent, already inside a branch vessel, to slip out of the unnamed branch vessel and enter the aortic lumen, leading to blockage of the unnamed branch vessel. This situation is extremely dangerous and requires emergency open surgery. Simultaneously, the resistance to blood flow in the vessel during placement also affects the positioning of the branch stent, and obstructed blood flow can cause various serious complications. Summary of the Invention

[0005] The purpose of this invention is to provide a branch sheath to solve at least one of the following problems: how to prevent branch stent displacement during stent delivery, how to avoid blood flow obstruction, and how to mitigate the impact of blood flow resistance on branch stent positioning.

[0006] To solve the above-mentioned technical problems, the present invention provides a branch sheath, comprising: a coated sleeve, a first connecting tube, a control wire, and a restraint coil;

[0007] The membrane sleeve has several drainage holes on its wall and is located at the distal end of the first connecting tube; the control wire passes through the first connecting tube and the distal end of the control wire is located inside the membrane sleeve.

[0008] The proximal end of the restraint coil is connected to the distal end of the first connecting tube. The distal end of the restraint coil is used to pass through and protrude from the bare end aperture of the branch support located inside the covered sleeve. The distal end of the control wire passes through the portion of the restraint coil that protrudes from the bare end aperture to pull and fix the bare end of the branch support.

[0009] Optionally, in the branch sheath, the control wire is configured to be retractable from the restraint coil, the covered sleeve, and the first connecting tube to release the branch support; wherein the proximal end of the control wire is fixedly connected to the second connecting tube to prevent the proximal end of the control wire from sliding.

[0010] Optionally, in the branch sheath, the radial dimension of the first connecting tube is the same as that of the second connecting tube, and the distal end of the second connecting tube is detachably connected to the proximal end of the first connecting tube.

[0011] Optionally, in the branch sheath, the detachable connection includes a heat-shrink tubing connection or a bio-adhesive bonding.

[0012] Optionally, in the branch sheath, the branch sheath further includes a third connecting tube; the third connecting tube is sleeved on the outer surface of the first connecting tube and the second connecting tube, and the distal end of the third connecting tube is connected to the proximal end of the coated sheath; the proximal end of the third connecting tube is provided with a limiting member, and the limiting member is also connected to the proximal end of the second connecting tube to prevent the sliding of the third connecting tube.

[0013] Optionally, in the branch sheath, the limiting element is a heat shrink tubing.

[0014] Optionally, in the branch sheath, the proximal end of the coated sleeve is connected to the distal end of the first connecting tube.

[0015] Optionally, in the branch sheath, the branch sheath further includes a connecting coil; the proximal end of the connecting coil is connected to the distal end of the first connecting tube, the distal end of the connecting coil is located inside the covered sleeve and is configured such that after the distal end of the binding coil extends out of the bare end aperture, it passes through and hooks onto the distal end of the connecting coil to form an extension, and the control wire passes through the extension.

[0016] Optionally, in the branch sheath, the axial length of the control wire extending beyond the distal end of the first connecting tube is greater than the axial length of the restraint coil extending beyond the bare end aperture; and the axial length of the coated sleeve is greater than or equal to the axial length of the branch support.

[0017] Optionally, in the branch sheath, the length range of the restraint coil is: a≥b+5; where a is the length of the restraint coil and b is the circumferential length at the location of the bare end of the branch support, in millimeters.

[0018] In summary, this invention provides a branch sheath, comprising: a covered cannula, a first connecting tube, a control wire, and a restraint coil. The covered cannula has several drainage holes on its wall, allowing blood to flow freely through these holes during the introduction and release of the branch stent, thus mitigating the impact of blood flow resistance on the delivery and positioning of the branch stent and reducing complications caused by poor blood flow. Furthermore, the covered cannula is located distal to the first connecting tube; the control wire passes through the first connecting tube, with its distal end located within the covered cannula; the proximal end of the restraint coil is connected to the distal end of the first connecting tube, and the distal end of the restraint coil passes through and extends beyond the bare end opening of the branch stent located within the covered cannula, thereby restraining the branch stent and preventing displacement due to the pull of the main stent after the main stent is released. Furthermore, the control wire passes through the portion of the bare end of the restraint coil that extends into the hole to pull and fix the bare end of the branch stent. Thus, after the branch stent is dislodged from the predetermined position during the operation, the branch stent can be pulled back into the branch blood vessel at any time by moving the first connecting tube under the pulling action of the control wire, thereby achieving precise control over the release position of the branch stent.

[0019] Therefore, the branch sheath provided by the present invention can not only prevent the branch stent from shifting and improve the accurate control of the branch stent release position, but also alleviate the influence of blood flow resistance on the branch stent input and positioning, and reduce complications caused by poor blood flow. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a branch sheath in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of a branch sheath after installation in one embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the constraint coil constraining the bare end in an embodiment of the present invention;

[0023] Figure 4This is a schematic diagram of the connection between the third connecting tube and the film-coated sleeve in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram showing the position of the limiting member in an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram showing the connection relationship between the connecting coil, the binding coil, the control wire, and the bare end in an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of the binding coil hooked on the connecting coil in an embodiment of the present invention;

[0027] Figure 8-10 This is a schematic diagram of the release of the branch support in an embodiment of the present invention;

[0028] The attached figures are labeled as follows:

[0029] 1-Control unit; 11-Control wire; 12-Second connecting pipe;

[0030] 2-Sheath section; 21-First connecting tube; 22-Covered sleeve; 23-Restraint coil; 231-Extension; 25-Connecting coil; 26-Third connecting tube; 27-Limiting element;

[0031] 3-Main support; 4-Branch support; 41-Bare end. Detailed Implementation

[0032] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clearly illustrate the objectives of the embodiments of the present invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and sometimes use different scales. It should also be understood that, unless specifically stated or indicated, the terms "first," "second," "third," etc., in the specification are only used to distinguish the various components, elements, steps, etc., in the specification, and are not used to indicate the logical or sequential relationships between the various components, elements, steps, etc.

[0033] In this article, "proximal" and "distal" are defined as follows: "distal" usually refers to the end of the medical device that first enters the patient's body during normal operation, while "proximal" usually refers to the end of the medical device that is closest to the operator during normal operation.

[0034] To address the aforementioned technical problems, this embodiment provides a branch sheath. Please refer to [link / reference]. Figure 1-2The system includes: a control wire 11, a first connecting tube 21, a covered sleeve 22, and a restraint coil 23; the covered sleeve 22 has a plurality of drainage holes 24 on its wall and is located at the distal end of the first connecting tube 21; the control wire 11 passes through the first connecting tube 21 and its distal end is located inside the covered sleeve 22; the proximal end of the restraint coil 23 is connected to the distal end of the first connecting tube 21, and the distal end of the restraint coil 23 is used to pass through the bare end aperture of the branch support 4 located inside the covered sleeve 22 and extend out of the bare end aperture, that is, the distal end of the restraint coil 23 is used to pass through all or part of the apertures of the bare end of the branch support 4 located inside the covered sleeve 22 and then extend out of the bare end aperture; the distal end of the control wire 11 passes through the portion of the restraint coil 23 that extends out of the bare end aperture to pull and fix the bare end 41 of the branch support 4.

[0035] As can be seen, the branch sheath provided in this embodiment has a drainage hole 24 on the wall of the covered cannula 22, so that blood can flow out smoothly through the drainage hole 24 during the introduction and release of the branch stent 4, thereby alleviating the influence of blood flow resistance on the delivery and positioning of the branch stent 4, and reducing complications caused by poor blood flow. Furthermore, the bare end 41 of the branch stent 4 is fixed by the traction of the restraint coil 23, preventing displacement of the branch stent 4 due to dragging of the main stent 3 during release. Moreover, the portion of the control wire 11 that extends through the bare end opening of the restraint coil 23 allows the branch stent 4 to be pulled back into the branch vessel at any time by moving the first connecting tube 21 after it has dislodged from its predetermined position during the procedure, under the traction of the control wire 11, thus achieving precise control over the release position of the branch stent 4.

[0036] The following is in conjunction with the appendix Figure 1-10 The branch sheath provided in this embodiment is described in detail below:

[0037] Please see Figure 1-3 The branch sheath includes a control section 1 and a sheath section 2. The control section 1 includes a control wire 11 and a second connecting tube 12. The control wire 11 controls the release of the branch support 4. That is, when releasing the branch support 4, the control wire 11 is pulled out of the restraint coil 23, the covered sheath 22, and the first connecting tube 21 to release the branch support 4. Before releasing the branch support 4, the distal end of the control wire 11 passes through the first connecting tube 21 and extends into the covered sheath 22, passing through the portion of the restraint coil 23 extending beyond the bare end opening, thereby enabling it to cooperate with the restraint coil 23 to control the release of the branch support 4.

[0038] Furthermore, since the branch stent 4 and the main stent 3 provided in this embodiment are an integrated structure, meaning that the branch stent 4 and the main stent 3 are interconnected, when the main stent 3 is released, it will exert a pulling force on the branch stent 4. This could not only cause the branch stent 4 to deviate from its target position, but also potentially cause it to slip into the aortic lumen, resulting in dangerous situations such as blockage of the branch vessel. Therefore, the distal end of the control wire 11 in the branch sheath provided in this embodiment, which extends through the bare end opening of the restraint coil 23, can also pull and fix the bare end 41 of the branch stent 4. This allows the branch stent 4 to be pulled back into the branch vessel at any time after it has dislodged from its predetermined position during the procedure. Under the pulling force of the control wire 11, the movement of the first connecting tube 21 can drive the movement of the control wire 11 and the bare end 41. This not only allows for precise control of the release position of the branch stent 4, but also prevents premature release of the branch stent 4.

[0039] Furthermore, the proximal end of the control wire 11 is fixedly connected to the second connecting tube 12 to prevent the proximal end of the control wire 11 from sliding into the first connecting tube 21, or to prevent accidental premature pulling out of the control wire 11. The second connecting tube 12 can be understood as a handle for pulling out the control wire 11, which facilitates the operator's pulling action and avoids accidental premature release of the branch support 4; on the other hand, it prevents the proximal end of the control wire 11 from detaching from the control and sliding into the first connecting tube 21. The radial dimension of the first connecting tube 21 is the same as the radial dimension of the second connecting tube 12. To facilitate intraoperative operation, the connection between the second connecting tube 11 and the first connecting tube 21 is detachable. The detachable connection includes, but is not limited to, connection via heat-shrink tubing or adhesion via bio-adhesive. Specifically, the portion of the control wire 11 extending from the proximal end of the first connecting tube 21 is inserted into the second connecting tube 12 and fixed therein, which can be fixed by welding or adhesion. When it is necessary to remove the control wire 11, the connection between the second connecting tube 12 and the proximal end of the first connecting tube 21 is disrupted, for example, by severing the heat shrink tubing or the bio-adhesive, to extract the control wire 11 and release the branch support 4. Optionally, the control wire 11 and the second connecting tube 12 are made of nickel-titanium alloy.

[0040] Please continue reading. Figure 1-3The sheath portion 2 includes at least a first connecting tube 21, a covered sleeve 22, and a restraint coil 23. The first connecting tube 21 forms the basic framework of the branch sheath. In one embodiment, the first connecting tube 21 provides support and fixation for the covered sleeve 22 and the restraint coil 23. Furthermore, both the first connecting tube 21 and the covered sleeve 22 are hollow tubes, meaning they each have an inner cavity that communicates at both ends. The distal end of the first connecting tube 21 connects to the proximal end of the covered sleeve 22, thus their inner cavities are interconnected.

[0041] The covered cannula 22 is used to accommodate the branch stent 4, preventing damage to the blood vessel wall during stent insertion. The axial length of the covered cannula 22 is greater than or equal to the axial length of the branch stent 4 to ensure that the branch stent 4 is completely enclosed within it. Furthermore, the wall of the covered cannula 22 is provided with several drainage holes 24. These drainage holes 24 allow blood to flow freely during the insertion and release of the branch stent 4, mitigating the impact of blood flow resistance on the delivery and positioning of the branch stent 4, and reducing complications caused by poor blood flow. Further, this embodiment does not limit the number of drainage holes 24; one, two, three, or four can be selected. However, to ensure the strength of the covered cannula 22, the proportion of the drainage hole 24 to the outer surface area of ​​the covered cannula 22 should not be too large; therefore, the number of drainage holes 24 should be appropriately selected.

[0042] Please refer to Figures 4-5. Since the coated sleeve 22 has several drainage holes 24, these drainage holes 24 may reduce the strength of the coated sleeve 22. Therefore, it is preferable to control the coated sleeve 22 and the binding coil 23 separately, so that the coated sleeve 22 is pulled out first, and then the control wire 11 is pulled to release the control wire 11 and the bare end 41 from the binding coil 23. In another embodiment, the branch sheath further includes a third connecting tube 26. The third connecting tube 26 is sleeved on the outer surface of the first connecting tube 21 and the second connecting tube 12. The first connecting tube 21 is not connected to the coated sleeve 22, but rather the distal end of the third connecting tube 26 is connected to the proximal end of the coated sleeve 22. Optionally, the connection method between the third connecting tube 26 and the coated sleeve 22 includes, but is not limited to, using shrink tubing heat fusion connection, using glue bonding, or directly fusing the proximal end of the coated sleeve 22 into the distal end of the third connecting tube 26.

[0043] To prevent the third connecting tube 26 from sliding, which could cause premature pulling out of the coated sleeve 22 or pushing the coated sleeve 22 toward the main support 3, a limiting member 27 is provided at the proximal end of the third connecting tube 26. The limiting member 27 is also connected to the proximal end of the second connecting tube 12. Furthermore, the limiting member 27 may include, but is not limited to, heat-shrink tubing, or a mechanical connection that is easy to disassemble. During the release process, the limiting member 27 is first separated from the second connecting tube 12 and the third connecting tube 26, then the third connecting tube 26 and the coated sleeve 22 are pulled out first, and finally the position of the branch support 4 is adjusted using the control wire 11, and the branch support 4 is released. Furthermore, the first connecting tube 21, the third connecting tube 26, and the coated sleeve 22 are made of nickel-titanium alloy.

[0044] Please continue reading. Figure 1 and 2 The proximal end of the restraint coil 23 is connected to the distal end of the first connecting tube 21. The distal end of the restraint coil 23 passes through all or part of the bare end holes of the branch bracket 4 and extends out of the bare end holes to restrain the bare end 41 of the branch bracket 4, preventing the branch bracket 4 from shifting due to the pull of the main bracket 3 after the main bracket 3 is released, thus ensuring the accuracy of the release position. The length of the restraint coil 23 can be greater than the axial length of the covered sleeve 22, that is, the distal end of the restraint coil 23 can extend out of the covered sleeve 22, or it can be less than or equal to the axial length of the covered sleeve 22, that is, the distal end of the restraint coil 23 is located in the covered sleeve 22. In this embodiment, the end of the branch bracket 4 away from the main bracket 3 is the free end, which is referred to as the bare end 41. Further, the branch bracket 4 can be a covered bracket, wherein, since the bare end holes are used for connection, the bare end 41 is not covered.

[0045] Furthermore, after the distal end of the binding coil 23 passes through the bare end aperture of the branch bracket 4 and extends out of the bare end aperture, as... Figure 2 As shown, the branch stent 4 is in a normal state, i.e., a non-compressed state. Furthermore, the bare ends 41 are not bound tightly but remain in a relaxed state. This is to maintain the gap between the bare ends 41, allowing blood to flow freely through the gap during the introduction and release of the branch stent 4, further mitigating the impact of blood flow resistance on the delivery and positioning of the branch stent 4, and ensuring smooth blood flow. Of course, as... Figure 8As shown, when adjusting the position of the branch stent 4, the control wire 11 and the restraint coil 23 are pulled by moving the first connecting tube 21. Given the intersection of the control wire 11 and the restraint coil 23, during the pulling process, the restraint coil 23 applies traction force to the bare segment through the constraint of the control wire 11, thereby tightening the bare segment and reducing the gap. However, the covered sheath 22 in the branch sheath provided in this embodiment is provided with several drainage holes 24, which is sufficient to ensure smooth blood flow and avoid complications caused by poor blood flow. When releasing the branch stent 4, the restraint coil 23 disengages from all the bare end gaps by pulling away the control wire 11 and applying slight external force, thus releasing the branch stent 4.

[0046] Furthermore, the binding coil 23 is made of polytetrafluoroethylene (PTFE). PTFE has a low coefficient of friction, which allows the binding coil 22 to quickly detach from the bare end aperture when the branch support 4 is released.

[0047] Please see Figure 6-7 Because the control wire 11 passes through the coated sheath 22 during the withdrawal process, and if the control wire 11 is too long, it can easily puncture the coated sheath 22 and the coating on the branch support 4 during the withdrawal process, causing damage to the coated sheath 22 and the branch support 4. Therefore, in order to shorten the length of the control wire 11 and ensure that the coated sheath 22 and the branch support 4 are not damaged, in one embodiment, the branch sheath further includes a connecting coil 25. The proximal end of the connecting coil 25 passes through the coated sheath 22 and connects to the distal end of the first connecting tube 21. The distal end of the connecting coil 25 is configured such that after the distal end of the restraint coil 23 extends out of the bare end aperture, it passes through and hooks onto the distal end of the connecting coil 25 to form an extension 231, through which the control wire 11 passes. Figure 7 As shown, the protrusion 231 is hook-shaped, making it easy to hook onto the connecting coil 25. Therefore, the restraining coil 23 bends upward and hooks onto the connecting coil 25, thus extending the restraining coil 23 upward. This allows the control wire 11 to pass through the restraining coil 23 at the position of the connecting coil 25, achieving the purpose of shortening the control wire 11 and avoiding damage to the film-coated sleeve 22 and the branch support 4 due to the control wire 11 being too long.

[0048] To ensure that the length of the restraining coil 23 is sufficient to hook onto the connecting coil 25, the length of the restraining coil 23 is within the range of: a ≥ b + 5; where the unit is millimeters; a is the length of the restraining coil 23, i.e., the axial length of the restraining coil 23 along the branch sheath before it passes through the bare end aperture; b is the circumferential length at the location of the bare end 41 of the branch support 4; wherein the circumferential length at the location of the bare end 41 of the branch support 4 is longer than the circumferential length of the middle section of the branch support 4, i.e., the bare end 41 of the branch support 4 is trumpet-shaped. Furthermore, to ensure that the control wire 11 can adjust the position of the branch support 4 and control its release, the axial length of the control wire 11 extending beyond the distal end of the first connecting tube 21 is greater than the axial length of the restraining coil 23 after it extends beyond the bare end aperture. In other words, along the axial direction of the first control tube 21, the length between the distal end of the straightened control wire 11 and the distal end of the first connecting tube 21 is greater than the axial length of the restraining coil 23 after it passes through the bare end 41.

[0049] For further details, please refer to Figure 4 , 8 -10, When conveying the branch support 4 and the main support 3, firstly, the branch support 4 is installed into the branch sheath, that is, the branch support 4 is housed in the covered sleeve 22, the binding wire 23 passes through the bare end hole of the branch support 4, and the control wire 11 passes through the binding coil 23. Then, after the compressed main support 3 is bundled, the compressed main support 3 and the branch support 4 are conveyed to the target position, and after the release position is determined, the main branch guide wire is pulled out to release the main support 3. Secondly, if the covered sleeve 22 is directly connected to the first connecting tube 21, the position of the branch support 4 can be adjusted by moving the first connecting tube 21 to drive the control wire 11 and the binding coil 23. After the release position is determined, if Figure 9 and 10 As shown, the connection between the first connecting tube 21 and the second connecting tube 22 is broken, the control wire 11 is pulled out, and the sheath portion 2 is moved as a whole to release the branch stent 4. Because the covered sheath 22 is provided with a drainage hole 24, blood can flow through the drainage hole 24 when the branch stent 4 is released, avoiding blood blockage and reducing complications caused by poor blood flow.

[0050] If the branch sheath is equipped with the third connecting tube 26 and the limiting member 27, the position of the branch bracket 4 can be adjusted by moving the third connecting tube 26 to drive the second connecting tube 12, the first connecting tube 21, the restraint coil 23, and the control wire 11. After determining the release position, the connection between the limiting member 27 and the third connecting tube 26 and the second connecting tube 12 is broken, and the third connecting tube 26 and the covered sleeve 23 are pulled out. Alternatively, the connection between the limiting member 27 and the third connecting tube 26 and the second connecting tube 12 is broken first, and the third connecting tube 26 and the covered sleeve 23 are pulled out. Then, the position of the branch bracket 4 is adjusted by moving the first connecting tube 21 to drive the control wire 11 and the restraint coil 23. Finally, the connection between the first connecting tube 21 and the second connecting tube 12 is broken, the control wire 11 is pulled out, and the first connecting tube 21 is pulled away to release the branch bracket 4.

[0051] In summary, this embodiment provides a branch sheath, comprising: a covered sheath 22, a first connecting tube 21, a control wire 11, and a restraint coil 23. The covered sheath 22 has several drainage holes 24 on its wall, allowing blood to flow freely through these holes during the introduction and release of the branch stent 4, thus mitigating the impact of blood flow resistance on the delivery and positioning of the branch stent 4, and reducing complications caused by poor blood flow. The covered sheath 22 is located distal to the first connecting tube 21; the control wire 11 passes through the first connecting tube 21, with its distal end located within the covered sheath 22. The proximal end of the restraint coil 23 is connected to the distal end of the first connecting tube 21, and its distal end passes through and extends beyond the bare end opening of the branch stent 4 within the covered sheath 22, thereby restraining the branch stent 4 to prevent displacement due to the pull of the main stent after the main stent is released. Furthermore, the control wire 11 passes through the portion of the restraint coil 23 extending beyond the bare end aperture to pull and fix the bare end 41 of the branch stent 4. Thus, after the branch stent 4 displaces from its predetermined position during the procedure, under the traction of the control wire 11, the branch stent 4 can be pulled back into the branch vessel at any time by moving the first connecting tube, achieving precise control over the release position of the branch stent 4. Therefore, the branch sheath provided in this embodiment not only prevents displacement of the branch stent 4 and improves the accurate control of the release position of the branch stent 4, but also alleviates the influence of blood flow resistance on the input and positioning of the branch stent, reducing complications caused by poor blood flow.

[0052] Furthermore, it should be understood that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A branch sheath, characterized in that, include: Film-coated sleeve, first connecting tube, control wire, and restraint coil; The membrane sleeve has several drainage holes on its wall and is located at the distal end of the first connecting tube; the control wire passes through the first connecting tube and the distal end of the control wire is located inside the membrane sleeve. The proximal end of the binding coil is connected to the distal end of the first connecting tube. The distal end of the binding coil is used to pass through the bare end aperture of the branch support located in the covered sleeve and extend out of the bare end aperture. The distal end of the control wire passes through the portion of the binding coil that extends out of the bare end aperture to pull and fix the bare end of the branch support. The first connecting tube is configured to drive the control wire and the restraint coil to pull the branch support, thereby adjusting the position of the branch support.

2. The branch sheath according to claim 1, characterized in that, The control wire is configured to be removable from the restraint coil, the covered sleeve, and the first connecting tube to release the branch support; wherein the proximal end of the control wire is fixedly connected to the second connecting tube to prevent the proximal end of the control wire from sliding.

3. The branch sheath according to claim 2, characterized in that, The radial dimension of the first connecting tube is the same as that of the second connecting tube, and the distal end of the second connecting tube is detachably connected to the proximal end of the first connecting tube.

4. The branch sheath according to claim 3, characterized in that, The detachable connection includes heat shrink tubing or bio-adhesive bonding.

5. The branch sheath according to claim 2, characterized in that, The branch sheath further includes a third connecting tube; the third connecting tube is sleeved on the outer surface of the first connecting tube and the second connecting tube, and the distal end of the third connecting tube is connected to the proximal end of the film-coated sheath; the proximal end of the third connecting tube is provided with a limiting member, and the limiting member is also connected to the proximal end of the second connecting tube to prevent the sliding of the third connecting tube.

6. The branch sheath according to claim 5, characterized in that, The limiting component is a heat shrink tubing.

7. The branch sheath according to claim 1, characterized in that, The proximal end of the coated sleeve is connected to the distal end of the first connecting tube.

8. The branch sheath according to claim 1, characterized in that, The branch sheath further includes a connecting coil; the proximal end of the connecting coil is connected to the distal end of the first connecting tube, the distal end of the connecting coil is located inside the covered sleeve and is configured such that the distal end of the binding coil extends out of the bare end aperture, passes through and hooks onto the distal end of the connecting coil to form an extension, and the control wire passes through the extension.

9. The branch sheath according to claim 1, characterized in that, The axial length of the control wire extending beyond the distal end of the first connecting tube is greater than the axial length of the restraint coil extending beyond the bare end aperture; and the axial length of the coated sleeve is greater than or equal to the axial length of the branch support.

10. The branch sheath according to claim 1, characterized in that, The length range of the binding coil is: a≥b+5; where a is the length of the binding coil and b is the circumferential length at the location of the bare end of the branch support, in millimeters.

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