Sheath, introducer sheath, introducer sheath assembly, and endoscope kit

Abstract

The application discloses a sheath tube, a guide sheath, a guide sheath assembly and an endoscope kit, and relates to the technical field of medical devices. The sheath tube disclosed by the application is used for a guide sheath, and the sheath tube comprises an inner liner tube and an outer covering skin, and the outer covering skin is sleeved on the outer periphery of the inner liner tube, wherein: the outer covering skin comprises a first outer covering section and a second outer covering section, the first outer covering section is arranged on one side of the second outer covering section close to the distal end of the inner liner tube, and the rigidity of the first outer covering section is smaller than the rigidity of the second outer covering section. The above scheme can at least solve the problem that the guide sheath placement operation is blocked.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a sheath, a guide sheath, a guide sheath assembly, and an endoscope kit. Background Technology

[0002] Ureteral guide sheaths are used in endoscopic examinations or surgeries in urology. They can create an examination / surgery channel within the urinary system to assist endoscopes or surgical instruments in passing through cavities such as the urethra and ureter, thereby improving the effectiveness and safety of examinations and treatments.

[0003] In related technologies, the sheath of a guide sheath includes an inner liner. The distal section of the inner liner is typically constructed to have better bending performance than subsequent sections. For example, a larger bending slit is opened on the distal side of the inner liner to give the portion of the sheath closer to its distal end better flexibility, accommodating insertion operations into narrow or complex cavities. However, in practice, the aforementioned guide sheaths are still prone to causing obstruction during insertion. Utility Model Content

[0004] This application provides a sheath, a guide sheath, a guide sheath assembly, and an endoscope kit, which can at least solve the problem of obstructed guide sheath insertion.

[0005] In a first aspect, embodiments of this application provide a sheath tube for guiding the sheath.

[0006] The sheath includes an inner liner and an outer skin, with the outer skin covering the outer periphery of the inner liner. The outer skin includes a first outer section and a second outer section. The first outer section is located on the side of the second outer section near the distal end of the inner liner, and the stiffness of the first outer section is less than that of the second outer section.

[0007] In some embodiments, the first outer covering is made of thermoplastic polyurethane.

[0008] In some embodiments, the second outer covering is made of low-density polyethylene.

[0009] In some embodiments, the outer skin is a heat-shrinkable film.

[0010] In some embodiments, the inner liner is a stainless steel fitting.

[0011] In some embodiments, the stiffness of the first outer sheath gradually increases along the axial direction from the distal end to the proximal end of the sheath.

[0012] In some embodiments, the stiffness of the second outer sheath gradually increases along the axial direction from the distal end to the proximal end of the sheath.

[0013] In some embodiments, the outer skin includes a connecting segment for connecting the first outer skin segment and the second outer skin segment, wherein the stiffness of the connecting segment is greater than the stiffness of the first outer skin segment and less than the stiffness of the second outer skin segment.

[0014] In some embodiments, the inner liner includes a first pipe segment and a second pipe segment, the first pipe segment being located on the side of the second pipe segment near the distal end of the inner liner, a first outer covering segment covering the first pipe segment, and a second outer covering segment covering the second pipe segment; wherein: the pipe wall of the first pipe segment is provided with a first curved slit extending spirally in the circumferential direction, and the pipe wall of the second pipe segment is provided with a plurality of second curved slits spaced apart in the axial direction.

[0015] In some embodiments, the first bending seam divides the first pipe segment into multiple pipe section units along the axial direction. Multiple rotating grooves are provided on the opposite sides of the pipe section units, and a lug is defined between two adjacent pipe section units. In two adjacent pipe section units, the lug of one of them is correspondingly provided in the rotating groove of the other. In the circumferential direction of the first pipe segment, adjacent lugs are mutually restrictive and fitted.

[0016] In some embodiments, the rotating groove is a rotating groove, and the end face of the lug corresponding to the rotating groove is arc-shaped.

[0017] In some embodiments, the inner liner is an integrally cut curved tube.

[0018] Secondly, embodiments of this application provide a guide sheath, including a handle and the sheath tube described in the first aspect of this application, wherein the handle is connected to the sheath tube.

[0019] Thirdly, embodiments of this application provide a guide sheath assembly, including an expander and the guide sheath described in the second aspect of this application, wherein the expander can be inserted into the guide sheath.

[0020] Fourthly, embodiments of this application provide an endoscope kit, including an endoscope and the guide sheath assembly described in the third aspect of this application, wherein the insertion portion of the endoscope can be inserted into the guide sheath.

[0021] The technical solution adopted in this application can achieve the following beneficial effects:

[0022] In the sheath disclosed in the embodiments of this application, by segmenting the outer skin, the stiffness of the first outer skin segment near the distal end of the sheath is set to be smaller, thereby weakening the deformation resistance of the distal end portion of the sheath, and the stiffness of the second outer skin segment near the proximal end of the sheath is set to be larger, thereby strengthening the deformation resistance of the proximal end portion of the sheath.

[0023] This layout reduces the overall stiffness of the first outer sheath section and the distal end of the inner liner tube, making it easier for the portion of the first outer sheath section corresponding to the sheath tube to bend and deform. At the same time, it reduces the constraint on the distal end of the inner liner tube and reduces the obstruction to the bending action of the distal end of the sheath tube. As a result, the portion of the sheath tube corresponding to the first outer sheath section has better bending performance, which can meet the bending performance requirements of narrow and complex cavities, thus enabling the guide sheath to be inserted smoothly.

[0024] In addition, this layout will make the overall rigidity of the second outer sheath section and the proximal side section of the inner liner tube stronger. The second outer sheath section and the corresponding inner liner tube section can provide reliable support performance in the rear section of the sheath tube, preventing the sheath tube from twisting or bending during the insertion of the guide sheath. It also facilitates the transmission of the thrust applied to the proximal end, making it easier to insert the guide sheath. Attached Figure Description

[0025] The accompanying drawings, which are provided to further illustrate this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application.

[0026] In the attached diagram:

[0027] Figure 1 This is a schematic diagram of the structure of the guide sheath assembly disclosed in some embodiments of this application;

[0028] Figure 2 This is a schematic diagram of the structure of the guide sheath disclosed in some embodiments of this application;

[0029] Figure 3 for Figure 2 A magnified view of a section at point A in the middle;

[0030] Figure 4 for Figure 2 A magnified view of a section at point B in the middle.

[0031] Explanation of reference numerals in the attached figures:

[0032] 100-Guide sheath, 110-Sheath tube, 111-Inner liner tube, 111a-First tube segment, 111a1-Tube section unit, 111a2-Rotating groove, 111a3-Lumber, 111b-Second tube segment, 111c-First curved slot, 111d-Second curved slot, 112-Outer skin, 112a-First outer cover section, 112b-Second outer cover section, 120-Handle

[0033] 200-Expander. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0035] In various embodiments of this application, "proximal end" and "distal end" refer to the position of the device (such as a guide sheath and its accessories) relative to the user in the usage environment. The end closer to the user is designated as the "proximal end", and the end farther from the user is designated as the "distal end".

[0036] To facilitate understanding of the sheath, guide sheath, guide sheath assembly, and endoscope kit provided in the embodiments of this application, the relevant technologies will first be introduced in conjunction with the application scenarios below.

[0037] Regarding the obstruction of guide sheath insertion in related technologies, the inventors discovered through research that the outer skin of the sheath in these technologies causes the aforementioned issues. Specifically, the outer skin of the guide sheath is typically a single, integral tube. Since the proximal portion of the sheath does not require high bending performance but still needs some support, the skin is chosen to have a certain degree of rigidity. However, as a closed tube, the skin constrains the distal segment of the inner liner, hindering the bending motion of the distal sheath. This makes it difficult for the guide sheath to pass through narrow or complex cavities (such as the ureter), resulting in obstructed guide sheath insertion.

[0038] In view of this, some embodiments of this application provide a sheath for guiding the sheath. The guiding sheath mentioned in the embodiments of this application is not limited to any specific type; exemplaryly, it can be a ureteral sheath used to establish an examination or surgical channel in the urinary system to assist in the entry of a uroscope or surgical instruments into the human body.

[0039] Please see Figures 1-4 The sheath 110 disclosed in this application includes an inner liner 111 and an outer skin 112. The outer skin 112 covers the outer periphery of the inner liner 111. The outer skin 112 includes a first outer section 112a and a second outer section 112b. The first outer section 112a is located on the side of the second outer section 112b near the distal end of the inner liner 111, and the stiffness of the first outer section 112a is less than the stiffness of the second outer section 112b.

[0040] In the sheath 110 disclosed in the embodiments of this application, the inner liner 111 is the main body of the sheath 110, and has an axially extending internal channel for the insertion part of an endoscope, etc. The outer skin 112 can provide protection around the inner liner 111 and also prevent external debris from entering the sheath 110.

[0041] In some embodiments, the inner liner 111 can be a stainless steel tube, which gives it superior strength and damage resistance, preventing breakage during insertion into the human body. Specifically, the inner liner 111 is made of 304 stainless steel. Of course, the embodiments of this application do not limit the specific material of the inner liner 111.

[0042] In some embodiments, the outer skin 112 can be a heat-shrinkable film, which can improve processing efficiency and reduce costs. Of course, the outer skin 112 can also be other forms of outer covering structure.

[0043] In the embodiments of this application, the outer skin 112 is segmented, including a first outer skin segment 112a corresponding to the inner liner tube 111 near the distal end and a second outer skin segment 112b corresponding to the inner liner tube 111 near the proximal end, wherein the stiffness of the first outer skin segment 112a is less than the stiffness of the second outer skin segment 112b. In this situation, when the outer covering 112 covers the outer periphery of the inner liner tube 111, the first outer covering segment 112a has relatively poor resistance to deformation. Firstly, this reduces the overall stiffness of the first outer covering segment 112a and the distal end segment of the inner liner tube 111. Therefore, during the insertion of the guide sheath 100 into the human body cavity, the sheath tube 110 is compressed, and the portion of the sheath tube 110 corresponding to the first outer covering segment 112a is more likely to bend and deform. Secondly, precisely because the stiffness of the first outer covering segment 112a is set to be smaller, its constraint effect on the distal end segment of the inner liner tube 111 is relatively reduced, and the mutual loss of internal forces within the sheath tube 110 is reduced, thus reducing the resistance to the bending action of the distal end segment of the sheath tube 110. As a result, the portion of the sheath tube 110 corresponding to the first outer covering segment 112a has better bending performance, which can meet the bending performance requirements of the sheath tube 110 in narrow and complex cavities, thereby enabling the guide sheath 100 to be inserted smoothly.

[0044] Furthermore, after the outer skin 112 covers the outer periphery of the inner liner tube 111, the second outer covering section 112b has a relatively stronger resistance to deformation. This makes the overall rigidity of the second outer covering section 112b and the proximal side section of the inner liner tube 111 stronger. The second outer covering section 112b and the corresponding inner liner tube 111 section can provide reliable support performance for the rear section of the sheath tube 110, preventing the sheath tube 110 from twisting or bending during the insertion of the guide sheath 100. It also facilitates the transmission of the thrust applied proximally, making it easier to insert the guide sheath 100. This arrangement also helps to improve the strength of the rear section of the sheath tube 110, thereby improving its damage resistance.

[0045] In some embodiments, the first outer covering 112a can be made of thermoplastic polyurethane (TPU). Thermoplastic polyurethane has a low modulus of elasticity, resulting in relatively low stiffness in the first outer covering 112a. However, it is important to note that thermoplastic polyurethane possesses excellent elastic properties, which makes the sheath 110 portion corresponding to the first outer covering 112a more prone to bending deformation, further improving the bending performance of the sheath 110. Simultaneously, the superior elasticity of the first outer covering 112a facilitates its adaptation to larger bending movements of the distal portion of the sheath 110, thereby preventing tearing.

[0046] It should be noted that the sidewall of the inner liner 111 is usually provided with a bending slot to enable the sheath 110 to bend. However, during the bending process of the sheath 110, the outer skin 112 is prone to getting stuck in the bending slot and being damaged, especially the distal part of the sheath 110, which has higher bending performance requirements and is more prone to this problem. In the embodiment where the first outer covering section 112a is made of thermoplastic polyurethane, the first outer covering section 112a has better elasticity. During the bending process of the sheath 110, when the first outer covering section 112a is about to get stuck in the bending slot, it can achieve faster deformation through its better elasticity, which can reduce the risk of getting stuck in the bending slot to a certain extent, thereby reducing the risk of being pinched and damaged.

[0047] In some embodiments, the second outer sheath 112b may be made of low-density polyethylene (LDPE). This is inexpensive and easier to process and assemble, thus reducing the overall cost of the sheath 110.

[0048] The embodiments of this application do not limit the specific materials of the first outer covering 112a and the second outer covering 112b.

[0049] In some embodiments, the stiffness of the first outer covering segment 112a gradually increases along the axial direction of the sheath 110 from the distal end to the proximal end. It should be understood that in the relevant skin covering schemes, the stiffness of the entire skin is approximately the same, which leads to a uniform bending performance of the entire sheath. However, during the insertion of the guide sheath into the human body cavity, the portion of the sheath closer to the distal end will produce a greater bending motion, while the subsequent portion of the sheath follows the motion of the forward portion to achieve adaptive bending. Therefore, the outer covering will hinder the bending performance of the forward portion of the sheath as a whole, creating an obstacle to the insertion operation of the guide sheath.

[0050] In this example, the stiffness of the first outer covering segment 112a is set to a gradient distribution, so that the portion of the first outer covering segment 112a closer to the distal end of the sheath 110 has a relatively poor resistance to deformation. In this way, it is equivalent to achieving a gradient distribution of stiffness in the portion of the sheath 110 corresponding to the first outer covering segment 112a. The closer to the distal end of the sheath 110, the smaller the overall stiffness. The portion of the sheath 110 corresponding to the first outer covering segment 112a that is further from its distal end will experience less resistance when bending. Therefore, the closer to its distal end, the easier it is for the sheath 110 to bend, thus making it more adaptable to narrow and complex cavity environments and enabling smooth insertion operations.

[0051] In one specific embodiment, the first outer covering section 112a includes a plurality of first skin units connected sequentially along the axial direction, and the stiffness of the first skin units gradually increases along the axial direction of the sheath tube 110 from the distal end to the proximal end.

[0052] In some embodiments, the stiffness of the second outer covering section 112b gradually increases along the axial direction from the distal end to the proximal end of the sheath 110. It should be understood that by setting the stiffness of the second outer covering section 112b to a gradient distribution, the portion of the second outer covering section 112b closer to the distal end of the sheath 110 has a relatively poor resistance to deformation. In this way, it is equivalent to achieving a gradient distribution of stiffness in the portion of the sheath 110 corresponding to the second outer covering section 112b, with the overall stiffness being smaller closer to the distal end of the sheath 110. The region of the portion of the sheath 110 corresponding to the second outer covering section 112b closer to its distal end will experience less resistance when bending. Therefore, the portion of the sheath 110 corresponding to the second outer covering section 112b closer to its distal end is more likely to achieve bending action, thereby better following the action of the forward portion to achieve adaptive bending, making the insertion operation of the guide sheath 100 smoother.

[0053] In one specific embodiment, the second outer covering 112b includes a plurality of second skin units connected sequentially along the axial direction, and the stiffness of the second skin units gradually increases along the axial direction of the sheath 110 from the distal end to the proximal end.

[0054] In some embodiments, the outer skin 112 includes a connecting section for connecting the first outer section 112a and the second outer section 112b. The stiffness of the connecting section is greater than that of the first outer section 112a and less than that of the second outer section 112b. It should be understood that, given the different bending performance requirements of different axial portions of the sheath 110, after the first outer section 112a and the second outer section 112b are fitted over the inner liner 111, a significant difference in stiffness can easily occur between the portion of the sheath 110 corresponding to the first outer section 112a and the portion corresponding to the second outer section 112b. This causes the portion of the sheath 110 corresponding to the first outer section 112a to bend during the insertion of the guide sheath 100, while the portion of the sheath 110 corresponding to the second outer section 112b cannot bend in time, thus hindering the insertion of the guide sheath 100.

[0055] In this example, a connecting section is provided between the first outer section 112a and the second outer section 112b. This section enables the sheath 110 to form a stiffness transition between the portion corresponding to the first outer section 112a and the portion corresponding to the second outer section 112b. As a result, the portion of the sheath 110 corresponding to the connecting section can quickly follow the bending action after the portion of the sheath 110 corresponding to the first outer section 112a bends, thereby avoiding obstruction of the insertion operation of the guide sheath 100.

[0056] In some embodiments, such as Figures 2-4 As shown, the inner liner 111 includes a first pipe section 111a and a second pipe section 111b. The first pipe section 111a is located on the side of the second pipe section 111b near the far end of the inner liner 111. A first outer covering section 112a covers the first pipe section 111a, and a second outer covering section 112b covers the second pipe section 111b. The pipe wall of the first pipe section 111a is provided with a first curved slit 111c that extends spirally in the circumferential direction, and the pipe wall of the second pipe section 111b is provided with a plurality of second curved slits 111d that are spaced apart in the axial direction.

[0057] It should be understood that the spiral-shaped first curved slit 111c is an open circumferential slit. Compared to the spaced second curved slits 111d on the second tube segment 111b, the first tube segment 111a has lower stiffness and relatively weaker resistance to elastic deformation. In conjunction with the first outer covering segment 112a, it further optimizes the bending performance of the portion of the sheath 110 near the distal end. Furthermore, the spiral-shaped first curved slit 111c extends spirally upwards around the axial direction of the first tube segment 111a, resulting in more uniform dimensions for each segment unit 111a1, avoiding abrupt changes in size such as large or small segments. This ensures more uniform axial bending characteristics for the first tube segment 111a, improving the smoothness of bending of the sheath 110.

[0058] As for the second pipe section 111b, it is provided with multiple second bending slits 111d distributed along the axial direction. This arrangement can give the second pipe section 111b a certain bending performance, while not reducing the stiffness of the second pipe section 111b too much. The second pipe section 111b and the second outer cover section 112b cooperate with each other to more reliably maintain the support performance of the part of the sheath tube 110 near the proximal end.

[0059] In some embodiments, such as Figure 2 and Figure 3 As shown, the first curved joint 111c divides the first pipe segment 111a into multiple pipe section units 111a1 along the axial direction. Multiple rotating grooves 111a2 are provided on opposite sides of the pipe section units 111a1. A lug 111a3 is defined between two adjacent pipe section units 111a1. In two adjacent pipe section units 111a1, the lug 111a3 of one of them is correspondingly provided in the rotating groove 111a2 of the other. In the circumferential direction of the first pipe segment 111a, adjacent lugs 111a3 are mutually restrictive and fitted.

[0060] It should be understood that the first bending joint 111c penetrates the wall of the first pipe segment 111a, thereby forming a movable gap between the divided pipe section units 111a1. The pipe section units 111a1 can contract or expand through the movable gap, thus smoothly realizing the bending action. The opposite side of the pipe section unit 111a1 refers to the side of the pipe section unit 111a1 opposite to the adjacent pipe section unit 111a1.

[0061] The lug 111a3 corresponds to the mating relationship of the rotating groove 111a2, which not only realizes the relative rotation of adjacent tube segment units 111a1, but also forms a nested and snap-fit ​​mating relationship between the lug 111a3 and the groove wall of the rotating groove 111a2 in the early circumferential direction, so that the two can achieve mutual limiting and stopping. Since the lug 111a3 and the rotating groove 111a2 are both part of the tube segment unit 111a1, this ensures that there is also a limiting and stopping relationship between the tube segment units 111a1. Therefore, in the embodiment of this application, the sheath 110 is subjected to... When circumferential rotation is applied (e.g., the sheath 110 adjusts its circumferential posture within the patient's cavity by rotation), the rotation effect is transmitted in each tube segment 111a1 through the cooperation of the lug 111a3 and the rotation groove 111a2. Due to the circumferential limiting and stopping cooperation of the lug 111a3 and the rotation groove 111a2, the proximal and distal ends of the inner liner tube 111 and the sheath 110 have approximately the same rotation effect, thereby improving the coaxiality of the sheath 110. This can prevent the first tube segment 111a from changing diameter or deviating during rotation.

[0062] In some embodiments, such as Figure 2 and Figure 3As shown, the rotating groove 111a2 is a rotating groove 111a2, and the end face of the lug 111a3 corresponding to the rotating groove 111a2 is arc-shaped. With this arrangement, when the sheath 110 is compressed and the free end of the lug abuts against the groove surface of the corresponding rotating groove 111a2, the lug 111a3 can abut against the groove surface of the rotating groove 111a2 through its arc-shaped end face. The arc-shaped end face allows for a larger contact area between the free end of the lug 111a3 and the groove surface of the rotating groove 111a2. This avoids mechanical damage caused by an insufficient contact area and optimizes the stability of the free end of the lug 111a3 rotating within the rotating groove 111a2.

[0063] In some embodiments, a support protrusion may be constructed on the outer wall of the first tube segment 111a, between the lugs 111a3 on both sides of the same tube segment unit 111a1. This creates a certain height difference between the support protrusion and the lugs 111a3 in the tube segment unit 111a1. During the bending of the sheath 110 and the relative rotation of adjacent tube segment units 111a1, the support protrusion can provide a certain support for the outer first outer cover section 112a, preventing it from being caught in the gap between the lugs 111a3 and thus preventing damage.

[0064] In some embodiments, the inner liner tube 111 is an integrally cut bent tube, that is, it adopts an integral cutting technology, which can improve processing efficiency and optimize the overall strength of the inner liner tube 111.

[0065] Please see Figures 1-4 Embodiments of this application also provide a guide sheath 100, which includes a handle 120 and a sheath tube 110 as mentioned in any of the foregoing solutions, with the handle 120 connected to the sheath tube 110. Thus, the guide sheath 100 possesses the beneficial effects of the aforementioned sheath tube 110, which will not be elaborated here.

[0066] Regarding the specific type of the guiding sheath 100, the embodiments of this application do not limit it. For example, the guiding sheath 100 can be a ureteral sheath, a percutaneous kidney sheath, a biliary drainage sheath, a neuroendoscopic sheath, a bronchial navigation sheath, etc.

[0067] Please see Figures 1-4 Embodiments of this application also provide a guide sheath assembly, which includes an expander 200 and a guide sheath 100 as mentioned in any of the foregoing schemes, wherein the expander 200 can be inserted into the guide sheath 100.

[0068] Please see Figures 1-4 Embodiments of this application also provide an endoscope kit, which includes an endoscope and the guide sheath assembly mentioned in any of the foregoing solutions, thus enabling the endoscope to possess the beneficial effects of the aforementioned guide sheath assembly, which will not be described in detail here. The insertion portion of the endoscope can be inserted into the guide sheath 100.

[0069] The endoscopes involved in the embodiments of this application may be bronchoscopes, pyeloscopes, esophagoscopes, gastroscopes, colonoscopes, otoscopes, rhinoscopes, oral endoscopes, laryngoscopes, colposcopes, laparoscopes, arthroscopes, etc. The embodiments of this application do not specifically limit the types of endoscopes.

[0070] The above embodiments of this application focus on describing the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be described in detail here.

[0071] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A sheath tube for guiding a sheath, characterized in that, The sheath includes an inner liner and an outer skin, the outer skin covering the outer periphery of the inner liner, wherein: The outer skin includes a first outer section and a second outer section. The first outer section is located on the side of the second outer section near the distal end of the inner liner tube, and the stiffness of the first outer section is less than that of the second outer section.

2. The sheath according to claim 1, characterized in that, The first outer covering is made of thermoplastic polyurethane; and / or the second outer covering is made of low-density polyethylene; and / or the outer skin is heat-shrinkable film; and / or the inner liner is a stainless steel pipe.

3. The sheath according to claim 1, characterized in that, Along the axial direction of the sheath from distal to proximal end, the stiffness of the first outer covering segment gradually increases; and / or, along the axial direction of the sheath from distal to proximal end, the stiffness of the second outer covering segment gradually increases; and / or, the outer covering skin includes a connecting segment for connecting the first outer covering segment and the second outer covering segment, the stiffness of the connecting segment being greater than the stiffness of the first outer covering segment and less than the stiffness of the second outer covering segment.

4. The sheath according to any one of claims 1 to 3, characterized in that, The inner liner includes a first pipe section and a second pipe section. The first pipe section is located on the side of the second pipe section near the far end of the inner liner. The first outer covering section covers the first pipe section, and the second outer covering section covers the second pipe section. The first pipe section has a first curved slit extending spirally in the circumferential direction, and the second pipe section has a plurality of second curved slits spaced apart in the axial direction.

5. The sheath according to claim 4, characterized in that, The first bending seam divides the first pipe segment into multiple pipe section units along the axial direction. Multiple rotating grooves are provided on the opposite sides of each pipe section unit, and a lug is defined between two adjacent pipe section units. In two adjacent pipe section units, the lug of one of them is correspondingly located in the rotating groove of the other. In the circumferential direction of the first pipe segment, adjacent lugs are mutually restrictive and fitted.

6. The sheath according to claim 5, characterized in that, The rotating groove is a rotating groove, and the end face of the lug corresponding to the rotating groove is arc-shaped.

7. The sheath according to claim 4, characterized in that, The inner lining tube is a one-piece cut curved tube.

8. A guiding sheath, characterized in that, It includes a handle and a sheath as described in any one of claims 1 to 7, wherein the handle is connected to the sheath.

9. A guide sheath assembly, characterized in that, It includes an expander and a guide sheath as described in claim 8, wherein the expander is insertable into the guide sheath.

10. An endoscope kit, characterized in that, It includes an endoscope and the guide sheath assembly of claim 9, wherein the insertion portion of the endoscope can be inserted into the guide sheath.

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