Recyclable sheath assembly and method of processing

Abstract

The application discloses a recyclable sheath assembly and a processing method. The recyclable sheath assembly comprises a slidingly nested sheath and a sheath core assembly. The sheath core assembly comprises a core tube, a locking piece is arranged on a distal end of the core tube and used for connecting an interventional instrument. The sheath is arranged outside the sheath core assembly. The core tube comprises a compliant section adjacent to the locking piece and a second extension section opposite to the compliant section and extending towards a proximal end. The compliant section has smaller rigidity than the second extension section. The sheath is divided into a loading section, a bending section and a first extension section from a distal end to a proximal end in an axial direction. The loading section is used for accommodating the interventional instrument. The sheath adopts a multilayer structure.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and in particular relates to a retrievable sheath assembly for easy delivery of interventional devices and its processing method. Background Technology

[0002] Interventional device delivery systems generally include a sheath assembly, which consists of a sheath core assembly and a sheath that slides outside the sheath core assembly. The distal ends of both can enter the human vascular system, while the proximal ends are connected to the operating handle. Due to the tortuous nature of the human vascular system and the consideration of long-distance operation, it is necessary to take into account the axial support and compliance of the distal end of the sheath assembly. Summary of the Invention

[0003] This application provides a retrievable sheath assembly, including a slidingly nested sheath and a sheath core assembly. The sheath core assembly includes a core tube, with a locking element for connecting an interventional device installed at the distal end of the core tube. The sheath tube is located on the outer periphery of the sheath core assembly. The core tube includes a compliant section adjacent to the locking element and a second extension section that is connected to the compliant section and extends proximally. The compliant section has less stiffness than the second extension section.

[0004] The sheath is axially divided into a loading section, a bending section, and a first extension section from distal to proximal. The loading section is used to house interventional instruments. The sheath has a multi-layered structure, including:

[0005] The inner sheath is distributed axially in the bendable section and the first extension section;

[0006] The inner liner tube is connected to the distal end of the inner sheath tube, and the inner liner tube is distributed in the loading section in the axial direction.

[0007] A metal tube, which is wrapped around the distal portion of the inner sheath and the outer periphery of the inner liner, and the metal tube is distributed axially in the bending section and the loading section.

[0008] An outer film is wrapped around the outer periphery of the metal tube, and the outer film is distributed axially in the bending section and the loading section.

[0009] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0010] Optionally, the outer periphery of the locking member has a limiting groove for connecting an interventional device. The proximal part of the interventional device is engaged in the limiting groove in the loaded state, and its axial position is limited by the limiting groove.

[0011] Optionally, the outer periphery of the locking member is fixed with a pressure strip that mates with each limiting groove. The pressure strip is restrained by the sheath tube to restrict the proximal part of the interventional device within the limiting groove.

[0012] Optionally, the pressure strip is made of a flexible material. Optionally, the metal tube includes a head tube, a main tube, and an extension tube connected sequentially from the distal end to the proximal end, wherein, in the axial direction, the head tube and the main tube are both distributed in the loading section, and the extension tube is distributed in the bending section.

[0013] Optionally, the head tube includes a body section, 3-6 expansion plates arranged circumferentially at the distal end of the body section, a first connector at the proximal end of the body section, and a second connector at the distal end of the main body tube. The first connector and the second connector are interlocked and complementary in shape.

[0014] Optionally, each expansion piece has a hollow area, which is a plurality of through holes arranged at intervals along the axial direction of the sheath tube, and the total area of ​​the through holes on each expansion piece is less than 50% of the area of ​​the expansion piece.

[0015] Optionally, on the same expansion piece, the area of ​​the through hole is larger the closer it is to the far end.

[0016] Optionally, the through holes are circular or elliptical, and the number of through holes on the same expansion piece is 2 to 5.

[0017] Optionally, the expansion plates are evenly arranged circumferentially, with a quantity of 3 to 6.

[0018] Optionally, the first connector is T-shaped.

[0019] Optionally, the body segment is hollowed out to form a developing area for mounting developing points.

[0020] Optionally, both the body segment and the first connector have through holes, and the inner liner and the outer membrane are thermally fused together at the through holes.

[0021] Optionally, each expansion piece has a hollowed-out area; the hollowed-out area is a strip-shaped hole that extends axially along the head end tube.

[0022] Optionally, there are two strip holes on the same expansion piece.

[0023] Optionally, the strip-shaped holes extend to the same width.

[0024] Optionally, the two ends of the strip hole along its length are arc-shaped inner edges.

[0025] Optionally, there is a gap between two adjacent expansion pieces, and each expansion piece has a narrowing portion at its proximal end, and the gap has a widening portion at its proximal end corresponding to the narrowing portion.

[0026] Optionally, the inner edge of the widened portion is a smooth curve.

[0027] Optionally, the central region of the spaced opening extends with equal width along its length.

[0028] Optionally, the width of the equal-width extension portion of the interval opening is approximately the same as the width of the strip hole.

[0029] Optionally, the proximal side of the strip-shaped hole extends beyond the narrowing portion of the expansion piece.

[0030] Optionally, the proximal side of the strip hole extends 1–5 mm beyond the narrowed portion of the expansion piece.

[0031] Optionally, the distal end of the expansion piece has a smooth outer edge.

[0032] Optionally, the head tube is cut from a nickel-titanium alloy tube, and the main tube and the extension tube are cut from stainless steel tubes.

[0033] Optionally, the extension tube is a hyaluronic acid tube.

[0034] Optionally, the core tube includes a compliant section adjacent to the locking element and a second extension section opposite to the compliant section and extending proximally, the compliant section having less stiffness than the second extension section.

[0035] Optionally, the core tube is a single, continuous thiourea tube;

[0036] Alternatively, the compliant section may be made of a hygroscopic tube, and the second extension section may be made of a steel cable tube made of metal wire.

[0037] Optionally, the length of the compliant section is 120mm to 180mm.

[0038] Optionally, the compliant section has a first reinforcing rib extending axially.

[0039] Optionally, the inner sheath adopts a multi-layer structure, with a second reinforcing rib extending axially in the interlayer. There are two second reinforcing ribs, one of which is located at the same circumferential position as the first reinforcing rib, and the other is located 180 degrees away from the first reinforcing rib in the circumferential position.

[0040] Optionally, the inner sheath consists of an inner layer, a braided layer, and an outer layer from the inside out, wherein the second reinforcing rib is located within the braided layer.

[0041] Optionally, the core tube includes a compliant section adjacent to the locking element and a second extension section opposite to the compliant section and extending proximally; the compliant section has a first reinforcing rib extending axially.

[0042] The extension tube is provided with a third reinforcing rib extending axially. The third reinforcing rib is one and is located in the same circumferential position as the first reinforcing rib; or there are two third reinforcing ribs, one of which is located in the same circumferential position as the first reinforcing rib, and the other is located 180 degrees away from the first reinforcing rib in the circumferential position.

[0043] Optionally, the inner sheath includes a distal portion in a bendable section and a proximal portion in a first extension section, wherein the distal portion has less stiffness than the proximal portion.

[0044] This application also provides a method for processing a recyclable sheath assembly, comprising providing a sheath core assembly and a sheath tube respectively and assembling them, wherein the method for processing the sheath tube includes:

[0045] Step S100: Provide an inner sheath and process a flared portion at the distal end of the inner sheath;

[0046] Step S200: The inner liner tube is fitted and fixed around the outer periphery of the flared portion;

[0047] Step S300: A metal tube is fitted around the outer periphery of the distal end of the inner sheath and around the outer periphery of the inner liner.

[0048] In step S400, the outer surface of the metal tube is covered in sections using an outer material, and the outer material of each section is melted to form an outer film.

[0049] The sheath may be the sheath described in this application.

[0050] Optionally, in step S200, the proximal end of the inner liner tube has multiple ear pieces arranged at intervals along the circumference. The multiple ear pieces are overlapped and wrapped around the outer periphery of the flared part, and then the multiple ear pieces are wrapped with a fixing sleeve and then heat-fused to fix them.

[0051] Optionally, 3 to 6 ear pieces are evenly arranged circumferentially.

[0052] Optionally, the inner liner is made of polymer material.

[0053] Optionally, the inner liner is made of PTFE.

[0054] Optionally, the fixing sleeve is made of a different polymer material than the inner liner tube.

[0055] Optionally, the retaining sleeve is made of Pebax material.

[0056] Optionally, step S400 specifically includes:

[0057] Step S410: Wrap the first connecting sleeve around the joint between the main tube and the head tube, wrap the head tube with the head sleeve, and heat-melt the first connecting sleeve and the head sleeve together.

[0058] Step S420: Wrap the outer casing around the main tube and fix it with heat fusion;

[0059] Step S430: Wrap the second connecting sleeve around the inner sheath tube at the proximal end of the extension tube and the adjacent part, and fix the second connecting sleeve by heat fusion.

[0060] Step S440: Wrap the connecting sleeve around the outer circumference of the extension tube and fix it by heat fusion.

[0061] Optionally, the main tube has a hollowed-out area with intervals, and guide ribs are formed between adjacent hollowed-out areas. In step S420, before wrapping the main body jacket around the main tube, a liner is placed in each hollowed-out area and fixed by heat fusion.

[0062] Optionally, the liner is made of Pebax material.

[0063] Optionally, the head end jacket and the connecting sleeve are made of TPU material.

[0064] Optionally, the first connecting sleeve, the second connecting sleeve, and the main outer sleeve are all made of Pebax material.

[0065] In this application, improvements to the sheath structure enable the retrievable sheath assembly to better adapt to complex interventional pathways while maintaining good mechanical properties. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the conveying system of this application;

[0067] Figure 2a This is a schematic diagram of the core tube assembly in one embodiment of this application;

[0068] Figure 2b This is a schematic diagram of the core tube assembly in one embodiment of this application;

[0069] Figure 3a This is a schematic diagram of the structure of the lock element in one embodiment of this application;

[0070] Figure 3b This is a schematic diagram of the structure of the lock element in one embodiment of this application;

[0071] Figure 4 This is a schematic diagram of the locking mechanism of the core tube assembly using a wired control method in one embodiment of this application;

[0072] Figure 5 for Figure 4 Diagram showing the interaction between the locking mechanism and the access device;

[0073] Figure 6 This is a schematic diagram of the core tube (compliant section) in one embodiment of this application;

[0074] Figure 7 for Figure 6 A structural schematic diagram of the core tube (compliant section) from another angle;

[0075] Figure 8 This is a schematic diagram of the sheath structure in one embodiment of this application;

[0076] Figure 9 This is a schematic diagram of the recyclable sheath assembly in one embodiment of this application;

[0077] Figure 10 This is a cross-sectional view of a retrievable sheath assembly according to an embodiment of this application;

[0078] Figure 11 for Figure 10 A schematic diagram of the structure after the interventional device is loaded;

[0079] Figure 12 for Figure 11 A schematic diagram of the structure of the interventional device during partial release;

[0080] Figure 13 for Figure 11 A schematic diagram of the structure after the interventional device has been fully released;

[0081] Figure 14 This is a schematic diagram showing the relative axial segments of each pipe fitting in one embodiment of this application;

[0082] Figure 15 A diagram showing the components inside the sheath;

[0083] Figure 16a This is a schematic diagram of the head end tube structure;

[0084] Figure 16b This is a schematic diagram of the unfolded structure of the head end tube in another embodiment;

[0085] Figure 17 This is a schematic diagram of the remote portion of the conveying system of this application;

[0086] Figure 18 This is a cross-sectional view of the inner sheath.

[0087] Figure 19 for Figure 18 Enlarged view of part A in the middle;

[0088] Figures 20-30 This is a schematic diagram showing the components and related changes involved in the assembly process during sheath processing in one embodiment of this application.

[0089] The annotations in the figure are explained as follows:

[0090] 100. Operating handle;

[0091] 200. Catheter;

[0092] 300. Sheath; 310. Loading section; 320. Bending section; 330. First extension section; 340. Head end tube; 341. Spacing opening; 342. Developing area; 343. First connector; 344. Expander; 345. Hollowed-out area; 346. Body section; 347. Through hole; 348. Narrowing section; 349. Proximal side of the strip hole;

[0093] 350. Main tube; 351. Second connector; 352. Finishing part; 353. Hollowed-out area; 354. Hollowed-out area; 355. Guide rib;

[0094] 360. Extension tube; 3601. Reinforcing rib (third reinforcing rib); 3602. Reinforcing rib (third reinforcing rib);

[0095] 370, Inner sheath; 370A, Distal portion; 370B, Proximal portion; 3701, PTFE inner layer; 3702, Braided layer; 3703, Reinforcing rib (second reinforcing rib); 3704, Braided layer; 3705, Outer layer;

[0096] 371. Distal end; 372. Core rod; 373. Frustum section; 374. Flared end; 375. Inner liner tube; 376. Cutting area; 377. Fixing sleeve;

[0097] 380. Outer film; 381. First connecting sleeve; 382. Head end outer sleeve; 383. First liner; 384. Second liner; 385. Main body outer sleeve; 386. Second connecting sleeve; 387. Connecting sleeve;

[0098] 400. Sheath core assembly;

[0099] 420. Core tube assembly; 421. Guide head; 422. Locking element; 4221. Lock hole; 4222. Cable divider; 4223. Pull cable; 4224. Locking rod; 4225. Cable sleeve; 4226. Limiting groove; 423. Pressure strip; 424. Inner core; 425. Core tube; 4251. Compliant section; 4252. Second extension section; 4253. Reinforcing rib (first reinforcing rib);

[0100] 500. Interventional device; 501. Connecting ear. Detailed Implementation

[0101] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0102] It should be noted that when a component is said to be "connected" to another component, it can be directly connected to the other component or it can be connected to a component in between. When a component is said to be "set on" another component, it can be directly set on the other component or it may be set to a component in between.

[0103] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0104] See Figure 1 One embodiment of this application provides a retrievable sheath assembly that can be applied to a delivery system for delivering interventional devices. The delivery system has a distal end and a proximal end, and includes an operating handle 100 at the proximal end and a retrievable sheath assembly connected to the operating handle 100 and extending distally.

[0105] The retrievable sheath assembly of this embodiment includes a sheath 300 and a sheath core assembly 400, wherein the sheath 300 is slidably fitted onto the outer periphery of the sheath core assembly 400. The sheath core assembly includes a core tube, and a locking device is fixed to the distal end of the core tube for connecting to an interventional device.

[0106] In other embodiments, the delivery system may further include a catheter 200 fixed relative to the operating handle 100, the catheter 200 being used to establish a channel to prevent damage to internal tissues during the reciprocating motion of the sheath 300. The interventional device is loaded into the sheath core assembly 400 and, encased in the sheath 300, enters the body along with the catheter 200. The sheath 300 can then move axially relative to both the catheter and the sheath 300 to release the interventional device and, if necessary, retrieve it.

[0107] See Figures 2a-2b The core tube assembly 420 includes a core tube 425. A locking member 422 is installed at the distal end of the core tube 425 for connecting interventional instruments. The core tube 425 can be made of metal materials such as thiourea tube and is fixed to the locking member 422 by welding, bonding or fasteners.

[0108] The distal end of the core tube 425 extends further into a locking member 422 and is fixed with a guide head 421. The distal end of the guide head 421 has a converging round head structure to facilitate its insertion and movement within the body. The position between the guide head 421 and the locking member 422 serves as the loading position for the interventional device. The compressed interventional device is located in this position and is limited and engaged with the locking member 422.

[0109] In one embodiment, an inner core 424 is provided inside the core tube 425. The distal end of the inner core 424 extends out to form a locking member 422 and is fixed with a guide head 421. The proximal extension length of the inner core 424 is not strictly limited. The position on the outer periphery of the inner core and between the guide head and the locking member serves as the loading position for the interventional device. The interventional device in a compressed state is in this position and is limited and engaged with the locking member 422. Since the core tube 425 does not extend to the loading position, the inner core 424 has a smaller outer diameter than the core tube 425, thus expanding the radial space of the loading position.

[0110] See Figures 3a-3b Locking components can have various structural forms, such as grooves connecting to connecting ears on the bracket, radially outward protruding heads, or wire control using long wires or wire loops to connect to the bracket. Regardless of the form, the purpose is to achieve connection with the connecting ears on the bracket.

[0111] In some embodiments, the locking member 422 has one or more limiting grooves 4226 on its outer periphery. The interventional device has a connecting ear 501 that is inserted into the limiting groove. The limiting groove 4226 is used for axial limiting of the interventional device, allowing the interventional device to be released and disengaged only after radial expansion. To prevent the connecting ear from accidentally disengaging or suddenly protruding outward and puncturing tissue during release, a pressure strip 423 that cooperates with each limiting groove 4226 is also fixed at the locking member 422. After loading, the pressure strip 423 is restrained by the sheath tube, restricting the connecting ear within the limiting groove 4226, further improving safety. During release, the flexible material pressure strip 423 flips outward, allowing the connecting ear to disengage from the locking member 422.

[0112] The inner core 424 and the core tube 425 are both tubular structures. Since there is no need for axial relative movement between the core tube 425 and the inner core 424, they are nested together and welded together. Welding points can be set at one or more locations. If necessary, bushings can be added at the welding points to fill the radial gap between the two. The inner core 424 and the core tube 425 are welded to the bushings respectively, and the bushings can be made of the same material as the core tube 425.

[0113] One end of the core tube 425 is directly or indirectly fixed to the proximal side of the lock 422, and the other end extends toward the operating handle.

[0114] In one embodiment, to facilitate bending and changing the distal orientation, the core tube 425 includes a compliant section 4251 adjacent to the locking member 422, and a second extension section 4252 that is opposite to the compliant section 4251 and extends proximally.

[0115] In one embodiment, the compliant section 4251 is a hysteresis tube with a length ranging from 120mm to 180mm, for example, 150mm.

[0116] The second extension section 4252 is made of steel cable tubing (made of braided or stranded metal wire); in other embodiments, the core tube 425 is a single piece of sodium hypochlorite tubing. The sodium hypochlorite tubing can ensure both axial support and radial bending. In order to control the bending direction of the compliant section 4251, the compliant section 4251 may have an axially extending reinforcing rib. The reinforcing rib is obtained by cutting the corresponding part of the sodium hypochlorite tubing (the uncut area or the area with relatively sparse cuts becomes the reinforcing rib). When the core tube 425 is a single piece of sodium hypochlorite tubing, the reinforcing rib may extend to the proximal end accordingly.

[0117] See Figure 4 and Figure 5 In some embodiments, the locking device is wire-controlled. The proximal end of the interventional device 500 has a connecting ear 501, which generally has a hanging hole or hook for threading the pull wire 4223. The locking device 422 has a locking hole 4221. The distal end of the locking rod 4224 engages with the locking hole 4221, and the proximal end can extend to the operating handle.

[0118] In the loaded state, the pull cable 4223 passes through the connecting lug 501 and is looped onto the locking bar 4224. Since the far end of the locking bar 4224 is inserted into the lock hole 4221, the pull cable 4223 can prevent the connecting lug 501 from disengaging from the lock 422. When release is required, the locking bar 4224 is pulled towards the near end and disengaged from the lock hole 4221, and the pull cable 4223 is also released, allowing the connecting lug 501 to disengage from the lock 422.

[0119] There are multiple connecting ears 501, and multiple pull wires 4223 can be configured. Each pull wire 4223 extends to the far end via a splitter 4222. In order to organize the wire bundle, a wire sleeve 4225 can be fitted around the core tube 425 to form an extension channel for the pull wire 4223.

[0120] The locking rod 4224 and the lock hole 4221 that work together form a locking mechanism. Multiple locking mechanisms can be configured as needed and arranged sequentially along the circumference of the lock 422.

[0121] See Figure 6 , Figure 7 When cutting section 4251, the cutting kerf width (i.e., laser spot diameter) is 0.1 to 1 mm, and the kerf spacing is 0.1 to 1 mm; among them, an uncut section extends along the axial direction to form a reinforcing rib 4253.

[0122] See Figures 8-9 To adapt to changes in distal orientation during bending or passage within the body, the outermost sheath 300 has varying degrees of hardness and softness at different axial locations. From distal to proximal, the sheath 300 includes a loading section 310, a bending section 320, and a first extension section 330. During use, it primarily bends near the proximal side of the loading area adjacent to the insertion device 500, i.e., where the bending section 320 is located.

[0123] See Figures 10-17 In one embodiment, the nesting relationship between the sheath 300 and the core tube assembly 420, as well as the release process of the interventional device, are illustrated. The figure also shows the approximate axial positional relationship of each segment of the sheath 300 and the core tube assembly 420. For each segment, the sheath 300 adopts a multi-layered composite structure, that is, for a certain segment, a multi-layered structure is adopted, and different components are included in the processing. The structure and process of the sheath 300 are also one of the improvements of this application. In this embodiment, the core tube assembly 420 includes a core tube 425, a locking member 422 is fixed on the core tube 425, and the locking member 422 extends further from the distal end of the core tube 425, with a guide head 421 fixed at the distal end. The distal end of the guide head 421 has a converging round head structure to facilitate its passage in the body. The position between the guide head 421 and the locking member 422 serves as the loading position for the interventional device. The compressed interventional device is in this position and is limited and engaged with the locking member 422.

[0124] In one embodiment, an inner core 424 is provided inside the core tube 425. The distal end of the inner core 424 extends out to the locking member 422 and is fixed with a guide head 421. The distal end of the core tube 425 only extends to the locking member 422. The proximal extension length of the inner core 424 is not strictly limited. Since the core tube 425 does not extend to the loading position, the inner core 424 has a smaller outer diameter than the core tube 425, which expands the radial space of the loading position.

[0125] In conjunction with the above embodiments, in one embodiment of this application, the sheath is axially divided from distal to proximal into a loading section 310, a bending section 320, and a first extension section 330, wherein the loading section 310 is used to house the interventional device 500, and the sheath adopts a multi-layer structure, including:

[0126] The inner sheath 370 is distributed axially in the bendable section and the first extension section;

[0127] The inner liner tube 375 is connected to the distal end of the inner sheath tube 370, and the inner liner tube 375 is distributed in the loading section in the axial direction.

[0128] Metal tubes are wrapped around the distal part of the inner sheath and the outer periphery of the inner liner. The metal tubes are distributed axially in the bending section and the loading section.

[0129] The outer membrane 380 is wrapped around the outer periphery of the metal tube, and the outer membrane 380 is distributed in the bending section and the loading section in the axial direction.

[0130] Figure 15 The diagram illustrates some visible components of the sheath 300. The distal portion of the sheath 300 generally has at least three layers: the inner and outer layers are made of polymer materials, and the middle layer is a metal tube. The middle layer adopts a three-section docking structure, which includes a head tube 340, a main tube 350, and an extension tube 360 ​​docked sequentially from the distal end to the proximal end. In the axial direction, the head tube and the main tube are distributed in the loading section, and the extension tube is distributed in the bending section.

[0131] The bendable section can be bent to change the orientation of the distal end of the sheath during delivery, while the first extension section mainly provides sufficient axial pushing and pulling force and has sufficient length to connect the operating handle.

[0132] The tip tube 340 is cut from a nickel-titanium alloy tube, while the main tube 350 and extension tube 360 ​​are cut from stainless steel tubes. Because the tip tube 340 and main tube 350 need to enclose the interventional device, they have a larger diameter than the extension tube 360. Figure 14 The axial position relationship is such that the connection between the main tube 350 and the extension tube 360 ​​is also flared and the diameter is changed accordingly.

[0133] See Figure 16a In one embodiment, the distal end of the head tube 340 has a plurality of spaced openings 341 along the circumferential direction, and an expansion piece 344 is located between two adjacent spaced openings. Each expansion piece 344 has a hollow area 345. In a preferred embodiment, the expansion pieces 344 are evenly arranged along the circumferential direction, and the number is 3 to 6, for example, 5.

[0134] Overall, the head tube 340 preferably adopts an integral structure, the body section 346 forms a developing area 342 in a hollowed-out manner for installing developing points, and the first connector 343 is T-shaped for docking with the main tube 350 and axially limiting it. Both the body section 346 and the first connector 343 have through holes 347 distributed on them, which can better fuse the polymer materials that serve as the inner and outer layers of the sheath.

[0135] The septum opening 341 is a strip-shaped notch, open at the distal end and closed at the proximal end. Since the head tube 340 is made of an elastic metal material such as nickel-titanium alloy, each expansion piece 344 can be radially folded outward. This allows it to adapt to the gradual deformation of the interventional device during release and prevents the interventional device from suddenly popping out at the end of release. In addition, when it is necessary to retrieve it, each expansion piece 344 is radially folded outward to form a flared mouth, which facilitates the gradual radial compression of the interventional device and its retraction into the sheath 300.

[0136] The hollow area 345 of the expansion piece 344 facilitates the deformation of the expansion piece and reduces the outward resistance. In one embodiment, the hollow area 345 is a strip hole that extends along the axial direction of the head end tube 340. On the same expansion piece, there are one, two or more strip holes.

[0137] In a preferred embodiment, the strip-shaped holes extend to a uniform width. Both ends of the strip-shaped holes have arc-shaped inner edges along their length. This prevents cracking caused by excessive stress concentration during deformation.

[0138] In one embodiment, each expansion piece 344 has a narrowing portion 348 at its proximal end, and the spacer opening has a corresponding widening portion at its proximal end, that is, corresponding to the narrowing portion 348.

[0139] To distribute stress, the inner edge of the widened section is made of a smooth curve, such as the teardrop-shaped large head.

[0140] In one embodiment, the spacer opening itself extends at a generally uniform width, except for the distal side which accommodates the chamfer of the expansion piece and the proximal side which is widened.

[0141] The width of the equal-width extension of the interval opening is approximately the same as the width of the strip hole. For example, the width of the strip hole is taken as the reference width, and the width of the equal-width extension of the interval opening is ±20% of the reference width.

[0142] To facilitate the outward folding of each expansion piece 344 at the narrowing portion 348 and reduce the deformation resistance on the proximal side of the narrowing portion, in one embodiment, the proximal side 349 of the strip hole extends beyond the narrowing portion of the expansion piece. In a preferred embodiment, the proximal side 349 of the strip hole extends beyond the narrowing portion of the expansion piece by 1 to 5 mm, for example, 1.5 to 3 mm.

[0143] To avoid safety hazards, in one embodiment, the distal end of the expansion piece has a smooth outer edge, for example, by using rounded corners, or by using an arc shape that protrudes distally.

[0144] See Figure 16b In one embodiment, each expansion piece 344 has a hollow area 345, which consists of multiple through holes spaced apart along the axial direction of the sheath tube. The total area of ​​the through holes on each expansion piece is less than 50% of the area of ​​the expansion piece. As can be seen in the figure, the area of ​​the through holes closer to the far end on the same expansion piece is larger. The through holes are circular or elliptical, and the number of through holes on the same expansion piece is 2 to 5.

[0145] Similar to the previous embodiment, the body section 346 of the head tube forms a developing area 342 in a hollowed-out manner for installing developing points. The first connector 343 is T-shaped for docking with the main tube and axially limiting its position. Through holes 347 are distributed on both the body section 346 and the first connector 343, allowing for better fusion of the polymer materials in the inner and outer layers of the sheath. An interval opening 341 is formed between adjacent expansion pieces 344. The interval opening 341 is a strip-shaped notch, open at the distal end and closed at the proximal end. The expansion pieces 344 narrow towards the distal end, and an arc-shaped edge is used at the farthest end to improve safety.

[0146] To prevent the metal material in the middle layer from scratching the blood vessel wall, the outermost layer of the sheath must at least wrap the head tube 340, the main tube 350, and the extension tube 360. The outermost outer membrane 380 can be made of polymer material. Since the metal part has a multi-segment structure, the outer membrane 380 also adopts a multi-segment splicing structure during processing and then melts it into one piece.

[0147] The inner layer of the sheath includes an inner sheath 370 and an inner liner 375. The inner sheath 370 extends proximally on one side and extends to the junction of the main tube 350 and the extension tube 360 ​​on the other side. The inner sheath 370 extends further distally from the junction of the main tube 350 and the extension tube 360 ​​through the inner liner 375 until it reaches the distal end of the head tube 340. The inner liner 375 may be made of PTFE material.

[0148] Along the axial direction of the inner sheath, the inner sheath includes a distal portion 370A in a bendable section and a proximal portion 370B in a first extension section, wherein the distal portion 370A has less stiffness than the proximal portion 370B, i.e., better compliance.

[0149] The extension tube 360 ​​can also be cut to form reinforcing ribs.

[0150] See Figures 18-19 The inner sheath 370 itself adopts a multi-layer structure, consisting of a PTFE inner layer 3701, a braided layer 3702, a braided layer 3704, and an outer layer 3705 from the inside out. Two reinforcing ribs 3703 (second reinforcing ribs) extending axially are fixedly wrapped between the braided layers 3702 and 3704.

[0151] One of the two reinforcing ribs 3703 is located in the same circumferential position as the reinforcing rib 4253 in the conforming section 4251, while the other is located 180 degrees away from the reinforcing rib 4253 in the same circumferential position. The braided layers 3702 and 3704 do not require a distinct layered structure and can be braided together to hold the reinforcing rib. The outer layer 3705 can be made of Pebax material.

[0152] The extension tube 360 ​​may be provided with a reinforcing rib 3601, and the reinforcing rib 3601 and the reinforcing rib 4253 are located on the same side of the radial direction, that is, in the same circumferential position.

[0153] In other embodiments, the extension tube 360 ​​is provided with two reinforcing ribs, namely reinforcing rib 3601 and reinforcing rib 3602. Reinforcing rib 3601 and reinforcing rib 4253 are located on the same side of the radial direction, that is, at the same circumferential position. The circumferential positions of reinforcing rib 3602 and reinforcing rib 4253 are 180 degrees apart.

[0154] The inner sheath 370 exists in both the bending section 320 and the first extension section 330. Since the bending section 320 has a larger bending angle when bending, the inner sheath 370 has different strengths in the bending section 320 and the first extension section 330. The inner sheath 370 is softer in the bending section 320. For example, the outer layer 3705 of the inner sheath 370 in the bending section 320 uses 30-59D Pebax, while the outer layer 3705 of the inner sheath 370 in the first extension section 330 uses 60-90D Pebax. The braided layer and the PTFE inner layer 3701 at different parts of the inner sheath 370 can use the same configuration.

[0155] See Figures 20-30 One embodiment of this application provides a method for processing a recyclable sheath assembly. The sheath core assembly can be manufactured using existing technology in addition to the methods described in the embodiments of this application. The processing of the sheath 300 includes:

[0156] Step S100: A flared portion is formed at the distal end of the inner sheath.

[0157] The distal end 371 of the inner sheath tube can be heated and softened, and combined with the inserted mandrel 372, the distal end 371 is enlarged to form a flared portion 374. A portion of the outer periphery of the mandrel 372 can be machined into a frustum section 373 according to the expected shape of the flared portion 374. In step S200, the inner liner tube is fitted and fixed onto the outer periphery of the flared portion;

[0158] Take a PTFE inner tube 375. The end of the inner tube 375 has ear pieces arranged at intervals along the circumference. The area between the ear pieces is the cutting area 376. Wrap this end around the flared part 374, and then wrap it with a fixing sleeve 377 and heat-melt it to connect the inner tube 375 to the far end 371 of the inner sheath tube.

[0159] The fixing sleeve 377 and the flared part 374 are made of the same material, such as Pebax, while the cutting area 376 facilitates the fusion of the fixing sleeve 377 and the flared part 374, ensuring the connection strength of the inner liner tube 375.

[0160] Step S300: A metal tube is fitted around the outer periphery of the inner sheath and the inner liner.

[0161] The extension tube 360, main tube 350, and head tube 340 are connected in sequence, and the adjacent tubes are axially limited by hooks, buckles, or other means. The head tube 340 is made of nickel-titanium alloy, while the extension tube 360 ​​and main tube 350 can be made of stainless steel.

[0162] The proximal end of the head tube 340 has a T-shaped first connector 343, and the distal end of the main tube 350 has a T-shaped second connector 351. The first connector 343 and the second connector 351 are complementary in shape and cooperate with each other for axial limiting.

[0163] The main tube 350 has a constriction section 352 on its proximal side, which connects to the extension tube 360 ​​via the constriction section 352. The connection can be made using conventional hooks or clips. The tube wall of the main tube 350 has hollowed-out areas 353 and 354, and between them are axially extending guide ribs 355. The guide ribs 355 can restrict the bending direction of the sheath tube 300. There are two guide ribs 355 arranged radially opposite each other.

[0164] The extension tube 360, main tube 350, and head end tube 340 are sequentially connected and then fitted onto the outside of the inner sheath tube 370 and inner liner tube 375. The position of the flared part 374 corresponds to the axial position of the constricted part 352. The inner liner tube 375 is slightly longer than the head end tube 340. The inner liner tube 375 is also cut at the position corresponding to the spacer opening 341 to accommodate the deformation of the expansion piece.

[0165] In step S400, the outer surface of the metal tube is covered in sections using an outer material, and the outer material of each section is melted to form an outer film.

[0166] Specifically, it includes:

[0167] Step S410: Wrap the first connecting sleeve 381 around the joint of the main tube 350 and the head tube 340, wrap the head tube 340 with the head sleeve 382, ​​and heat-melt fix the first connecting sleeve 381 and the head sleeve 382.

[0168] The head end sleeve 382 is also slightly longer than the head end tube 340 and roughly aligned with the inner liner tube 375. Then, the first connecting sleeve 381 and the head end sleeve 382, ​​together with the corresponding positions of the inner liner tube 375, are heat-fused to fix the joint between the main body tube 350 and the head end tube 340, as well as the inner and outer parts of the head end tube 340.

[0169] First lining piece 383 and second lining piece 384 are placed in the hollowed-out areas 353 and 354, and then heat-fused to the corresponding positions of the inner lining tube 375. The first lining piece 383 and second lining piece 384 are then inserted into and filled into the corresponding hollowed-out areas.

[0170] Step S420: Wrap the outer casing 385 around the main body tube 350 and fix it with heat fusion;

[0171] The distal end of the main body sleeve 385 is roughly aligned with the proximal end of the first connecting sleeve 381, and the proximal end of the main body sleeve 385 wraps around the joint of the extension tube 360 ​​and the main body tube 350.

[0172] The head end jacket 382 requires better flexibility and can be made of materials such as TPU. The first connecting sleeve 381, the first liner 383, the second liner 384, and the main body jacket 385 can be made of materials with better strength, such as Pebax. The first liner 383 and the second liner 384 can be thinner than the main body jacket 385. For example, the thickness of the first liner 383 and the second liner 384 is about 0.15mm, while the thickness of the main body jacket 385 can be increased to 0.35mm.

[0173] In addition, the first connecting sleeve 381 requires greater strength, so a relatively hard material can be selected, such as 60-72D. The main outer sleeve 385 mainly provides wrapping and protection, so the hardness can be appropriately reduced, such as 40-55D.

[0174] Step S430: Wrap the second connecting sleeve 386 around the inner sheath 370 at the proximal end of the extension tube 360 ​​and the adjacent part, and fix the second connecting sleeve 386 by heat fusion.

[0175] Step S440: Wrap the connecting sleeve 387 around the outer periphery of the extension tube 360 ​​and fix it by heat fusion.

[0176] The axial position of the connecting sleeve 387 is such that the proximal end is connected to the second connecting sleeve 386, and the distal end is connected to the main body outer sleeve 385.

[0177] The second connecting sleeve 386 uses Pebax or similar materials for higher strength. The connecting sleeve 387, located at the bend, requires better flexibility and can be made of materials such as TPU. Furthermore, the connecting sleeve 387 prevents the internal metal tube from directly contacting and scratching blood vessels, and also serves a sealing function.

[0178] The materials wrapped around the extension tube 360, the main tube 350, and the head tube 340 are eventually fused together to form an outer film 380. Finally, the part of the head tube 340 that extends beyond the end is heat-fused to close the opening. The part corresponding to the interval opening 341 can also be cut to accommodate the possible deformation of the interval opening 341, or to utilize the elasticity of the material of the head sleeve 382 itself.

[0179] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered to be within the scope of this specification. When technical features of different embodiments are embodied in the same drawing, it can be regarded as the drawing also disclosing examples of combinations of the various embodiments involved.

[0180] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A retrievable sheath assembly, comprising a slidingly nested sheath and a sheath core assembly, the sheath core assembly including a core tube, the distal end of which is fitted with a locking element for connecting an interventional device, the sheath tube being located on the outer periphery of the sheath core assembly, characterized in that, The core tube includes a compliant section adjacent to the locking element, and a second extension section opposite the compliant section and extending proximally, the compliant section having less stiffness than the second extension section; The sheath is axially divided into a loading section, a bending section, and a first extension section from distal to proximal. The loading section is used to house interventional instruments. The sheath has a multi-layered structure, including: An inner sheath, axially comprising a distal portion in a bendable section and a proximal portion in a first extension, wherein the distal portion has less stiffness than the proximal portion. The inner liner tube is connected to the distal end of the inner sheath tube, and the inner liner tube is distributed in the loading section in the axial direction. A metal tube, which wraps around the distal portion of an inner sheath and the outer periphery of an inner liner, is distributed axially in a bendable section and a loading section. The metal tube includes an extension tube, which is distributed in the bendable section and is made of thiohide tubing. An outer film is wrapped around the outer periphery of the metal tube, and the outer film is distributed axially in the bending section and the loading section.

2. The recyclable sheath assembly as claimed in claim 1, characterized in that, The outer periphery of the locking member has a limiting groove for connecting interventional instruments. The proximal part of the interventional instrument is engaged in the limiting groove when loaded, and its axial position is limited by the limiting groove.

3. The recyclable sheath assembly as described in claim 2, characterized in that, The outer periphery of the locking member is fixed with pressure strips that cooperate with each limiting groove. The pressure strips are constrained by the sheath tube to restrict the proximal part of the interventional device within the limiting groove. The pressure strips are made of flexible material.

4. The recyclable sheath assembly as claimed in claim 1, characterized in that, The metal tube comprises, from distal to proximal end, a head end tube, a main body tube, and an extension tube connected sequentially, wherein, axially, the head end tube and the main body tube are both distributed in the loading section.

5. The recyclable sheath assembly as claimed in claim 4, characterized in that, The head end tube includes a body section, 3-6 expansion plates arranged circumferentially at the distal end of the body section, a first connector at the proximal end of the body section, and a second connector at the distal end of the main body tube. The first connector and the second connector are interlocked and complementary in shape.

6. The recyclable sheath assembly as claimed in claim 5, characterized in that, Each expansion piece has a hollow area, which is a plurality of through holes arranged at intervals along the axial direction of the sheath tube. The total area of ​​the through holes on each expansion piece is less than 50% of the area of ​​the expansion piece.

7. The recyclable sheath assembly as claimed in claim 6, characterized in that, On the same expansion piece, the area of ​​the through hole is larger the closer it is to the far end.

8. The recyclable sheath assembly as claimed in claim 6, characterized in that, The through holes are circular or elliptical, and the number of through holes on the same expansion piece is 2 to 5.

9. The recyclable sheath assembly as claimed in claim 5, characterized in that, Each expansion piece has a hollowed-out area, which is a strip-shaped hole that extends axially along the head end tube.

10. The recyclable sheath assembly as claimed in claim 9, characterized in that, There is a gap between two adjacent expansion pieces, and each expansion piece has a narrowing portion at the proximal end. The gap has a widening portion at the proximal end that corresponds to the narrowing portion.

11. The recyclable sheath assembly as claimed in claim 10, characterized in that, The proximal side of the strip-shaped hole extends beyond the narrowing section of the expansion piece.

12. The recyclable sheath assembly as claimed in claim 1, characterized in that, The core tube extends distally from the locking member, and a guide head is fixed at the distal end of the extension. The loading position is between the guide head and the locking member, and the compressed interventional device is located in this loading position and connected to the locking member.

13. The recyclable sheath assembly as claimed in claim 12, characterized in that, The core tube contains an inner core, and the distal end of the inner core extends out to form a locking element and is fixed with a guide head. The inner core is fixed relative to the core tube.

14. The recyclable sheath assembly as claimed in claim 1, characterized in that, The core tube is a complete sodium hypo hyaluronic acid tube; Alternatively, the compliant section may be made of a hygroscopic tube, and the second extension section may be made of a steel cable tube made of metal wire.

15. The recyclable sheath assembly as claimed in claim 1, characterized in that, The length of the compliant section is 120mm to 180mm; the compliant section has a first reinforcing rib extending along the axial direction.

16. The recyclable sheath assembly as claimed in claim 15, characterized in that, The inner sheath has a multi-layer structure, with two second reinforcing ribs extending axially in the interlayer. One of the second reinforcing ribs is located at the same circumferential position as the first reinforcing rib, while the other second reinforcing rib is located 180 degrees away from the first reinforcing rib in the circumferential direction.

17. The recyclable sheath assembly as claimed in claim 16, characterized in that, The inner sheath consists of an inner layer, a braided layer, and an outer layer from the inside out, wherein the second reinforcing rib is located within the braided layer.

18. The recyclable sheath assembly as claimed in claim 5, characterized in that, The core tube includes a compliant section adjacent to the locking element, and a second extension section opposite the compliant section and extending proximally; the compliant section has a first reinforcing rib extending axially. The extension tube is provided with a third reinforcing rib extending axially. The third reinforcing rib is one and is located in the same circumferential position as the first reinforcing rib; or there are two third reinforcing ribs, one of which is located in the same circumferential position as the first reinforcing rib, and the other is located 180 degrees away from the first reinforcing rib in the circumferential position.

19. A method for processing a recyclable sheath assembly as described in any one of claims 1 to 18, characterized in that, This includes providing and assembling a sheath core assembly and a sheath tube, wherein the processing method of the sheath tube includes: Step S100: Provide an inner sheath and process a flared portion at the distal end of the inner sheath; Step S200: The inner liner tube is fitted and fixed around the outer periphery of the flared portion; Step S300: A metal tube is fitted around the outer periphery of the distal end of the inner sheath and around the outer periphery of the inner liner. In step S400, the outer surface of the metal tube is covered in sections using an outer material, and the outer material of each section is melted to form an outer film.

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