Guiding sheath components, guiding sheath and its sealing structure

Abstract

This application belongs to the field of medical device technology, specifically relating to a guide sheath component, a guide sheath, and its sealing structure. The sealing structure includes a flexible head. The flexible head can be disposed at the distal end of the sheath, with its inner circumferential surface radially protruding beyond the inner circumferential surface of the sheath. The flexible head can be fitted over an expander and can be press-fitted with the expander to seal at least a portion of the gap between the distal end of the sheath and the expander; alternatively, the flexible head can be fitted at the distal end of the expander, with its outer circumferential surface radially protruding beyond the outer circumferential surface of the expander. The flexible head can contact the distal end of the sheath to seal at least a portion of the gap between the distal end of the sheath and the expander. The flexible head of this application can seal the gap between the distal end of the sheath and the expander, thereby preventing human body cavities from entering the gap and being clamped, thus solving the problem of tissue tearing leading to a stress response in the patient.

Description

Technical Field

[0001] This application belongs to the field of medical device technology, specifically relating to a guide sheath component, a guide sheath, and its sealing structure. Background Technology

[0002] Guide sheaths are commonly used in urological endoscopic examinations or surgeries. They can establish an examination / operative channel within the urinary system to assist endoscopes and surgical instruments in passing through cavities such as the urethra and ureters, thereby improving the effectiveness and safety of examinations and treatments.

[0003] However, from a clinical perspective, patients often exhibit significant stress responses when the surgeon inserts the guide sheath into the ureter. Therefore, how to avoid stress responses in patients during guide sheath insertion is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this application is to provide a guide sheath component, a guide sheath, and a sealing structure thereof, which can solve the problem that patients are prone to stress reactions when inserting current guide sheaths.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, embodiments of this application provide a sealing structure for a guide sheath, the sealing structure including a flexible head.

[0007] The flexible head can be located at the distal end of the sheath, with its inner circumferential surface protruding radially beyond the inner circumferential surface of the sheath. The flexible head can be fitted over the expander and can be interference-fitted with the expander to seal at least a portion of the gap between the distal end of the sheath and the expander; or...

[0008] The flexible head can be fitted onto the distal end of the expander, and the outer peripheral surface of the flexible head protrudes radially from the outer peripheral surface of the expander. The flexible head can contact the distal end of the sheath to seal at least a portion of the gap between the distal end of the sheath and the expander.

[0009] Secondly, embodiments of this application provide a guide sheath component, including the aforementioned sealing structure, wherein the guide sheath component is a sheath tube or an expander.

[0010] Thirdly, embodiments of this application provide a guide sheath, including the sealing structure described above.

[0011] In this embodiment, the sealing structure includes a flexible head. When using the sealing structure of this application, the flexible head can be placed at the distal end of the sheath or sleeved on the distal end of the expander. When the flexible head is placed at the distal end of the sheath, the inner circumferential surface of the flexible head protrudes radially from the inner circumferential surface of the sheath. Therefore, after the expander is inserted into the flexible head, the expander will be interference-fitted with the flexible head, thereby sealing the gap between the distal end of the sheath and the expander. This can prevent the body's cavity tissue from entering the gap and being clamped.

[0012] When the flexible head is fitted onto the distal end of the expander, the outer peripheral surface of the flexible head protrudes radially beyond the outer peripheral surface of the expander. The flexible head can contact the distal end of the sheath to seal the gap between the distal end of the sheath and the expander. This also prevents human body cavity tissue from entering the gap between the distal end of the sheath and the expander and being clamped.

[0013] As can be seen from the above analysis, the sealing structure of this application can prevent human body cavity tissue from entering the gap between the distal end of the sheath and the dilator. This can avoid the sheath and dilator clamping the cavity tissue, thereby solving the problem of the cavity tissue being torn and causing the patient to have a stress response. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the assembly of the sealing structure and the sheath tube disclosed in the embodiments of this application, and an enlarged schematic diagram of point A therein;

[0015] Figure 2 This is an explosion diagram of the sealing structure and sheath disclosed in the embodiments of this application;

[0016] Figure 3 This is a cross-sectional view of the sealing structure and sheath tube after assembly, as disclosed in the embodiments of this application;

[0017] Figure 4 This is a longitudinal sectional view of the sealing structure disclosed in the embodiments of this application;

[0018] Figure 5 This is a cross-sectional view of the sealing structure, sheath, and expander after assembly, as disclosed in the embodiments of this application;

[0019] Figure 6 This is a cross-sectional view of a sealing structure disclosed in another embodiment of this application;

[0020] Figure 7 This is a schematic diagram of the guide sheath disclosed in the embodiments of this application, and an enlarged schematic diagram of point B therein.

[0021] Explanation of reference numerals in the attached figures:

[0022] 100. Flexible head; 110. First part; 120. Second part; 130. Guide surface; 140. Clearance space; 200. Support; 210. Recess; 220. Clearance notch; 300. Sheath; 310. Main body; 320. Bending part; 330. Skin; 400. Expander; 500. Gap; 600. Operating handle. Detailed Implementation

[0023] 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, not all, of the embodiments of this application. 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.

[0024] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] The guide sheath component, guide sheath, and its sealing structure provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0026] In various embodiments of this application, "proximal end" and "distal end" refer to the relative positions of the guide sheath and its components 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".

[0027] Typically, a guiding sheath consists of a sheath tube and a dilator. When inserting the guiding sheath, the sheath tube is fitted over the dilator so that the sheath tube is inserted into the ureter under the guidance of the dilator. After the guiding sheath reaches the predetermined position, the dilator can be withdrawn from the sheath tube. The inventors discovered that after the sheath tube is fitted over the dilator, a gap exists between the distal end of the sheath tube and the dilator. Therefore, during the insertion of the guiding sheath, the body's cavities may be squeezed into this gap and thus clamped by the sheath tube and dilator. Further insertion of the guiding sheath can cause tearing of this part of the cavity tissue, which obviously causes a stress response in the patient.

[0028] like Figures 1 to 6As shown in the embodiment of this application, a sealing structure for a guide sheath is disclosed, the sealing structure including a flexible head 100. Optionally, the flexible head 100 may be made of a soft polymer medical-grade material such as silicone rubber.

[0029] The flexible head 100 is located at the distal end of the sheath 300. The inner circumferential surface of the flexible head 100 protrudes radially from the inner circumferential surface of the sheath 300. The flexible head 100 can be fitted over the expander 400 and can be interference-fitted with the expander 400 to seal at least a portion of the gap 500 between the distal end of the sheath 300 and the expander 400. In other words, the flexible head 100 can seal at least a portion of the gap 500 in its circumferential direction. In this embodiment, the inner circumferential surface of the flexible head 100 protrudes radially from the inner circumferential surface of the sheath 300. Therefore, after the expander 400 is inserted into the flexible head 100, the expander 400 will be interference-fitted with the flexible head 100, thereby sealing the gap 500 between the distal end of the sheath 300 and the expander 400. This prevents human body cavity tissue from entering the gap 500 and being clamped.

[0030] Optionally, after the expander 400 passes through the entire assembly of the flexible head 100 and the sheath 300, at least a portion of the flexible head 100 may be located within the gap 500 between the expander 400 and the sheath 300. In this case, at least a portion of the flexible head 100 is sleeved inside the sheath 300, and the distal end face of the flexible head 100 is flush with or extends beyond the distal end face of the sheath 300, thereby sealing the gap 500; or, all portions of the flexible head 100 may be located outside the gap 500 between the expander 400 and the sheath 300 (e.g., Figure 5 As shown in the diagram, at this time, the proximal end face of the flexible head 100 is in contact with the distal end face of the sheath 300, and the flexible head 100 can also seal the gap 500. This application does not limit the placement of the flexible head 100, as long as it can satisfy the following: after the expander 400 passes through the entire assembly of the flexible head 100 and the sheath 300, the flexible head 100 can seal at least a portion of the gap 500 between the distal end of the sheath 300 and the expander 400. At this time, the flexible head 100 can prevent at least a portion of the gap 500 in its circumferential direction from communicating with the space outside the gap 500.

[0031] Alternatively, the flexible head 100 can be fitted onto the distal end of the expander 400, with its outer peripheral surface protruding radially beyond the outer peripheral surface of the expander 400. In other words, the flexible head 100 is fitted onto the outside of the distal end of the expander 400, and can contact the distal end of the sheath 300 to seal at least a portion of the gap 500 between the distal end of the sheath 300 and the expander 400. That is, the flexible head 100 can seal at least a portion of the gap 500 in its circumferential direction. In this embodiment, the outer peripheral surface of the flexible head 100 protrudes radially beyond the outer peripheral surface of the expander 400, and the flexible head 100 can contact the distal end of the sheath 300 to seal the gap 500 between the distal end of the sheath 300 and the expander 400. This also prevents human body cavities from entering the gap 500 and being clamped.

[0032] Similarly, after the expander 400 passes through the entire assembly of the flexible head 100 and the sheath 300, at least a portion of the flexible head 100 may be located within the gap 500 between the expander 400 and the sheath 300, at which point the flexible head 100 contacts the inner circumferential surface of the distal end of the sheath 300; or, all portions of the flexible head 100 may be located outside the gap 500 between the expander 400 and the sheath 300, at which point the proximal end face of the flexible head 100 fits against the distal end face of the sheath 300, which will not be described further in this application.

[0033] It should be noted that the flexible head 100 has an internal sleeve space that extends along its own axis, so it can be sleeved outside the expander 400; the flexible head 100 can be a ring structure, in which case the flexible head 100 can completely seal the gap 500, that is, it can seal all parts of the gap 500 in its own circumferential direction; or the flexible head 100 can also be an arc structure, in which case the flexible head 100 seals a part of the gap 500 in its own circumferential direction.

[0034] The axial direction mentioned above is Figure 3 The direction indicated by the x-arrow line is radial, which is perpendicular to the x-arrow line. For example... Figure 3 The directions indicated by the y-arrow and z-arrow lines.

[0035] In one optional embodiment, the flexible head 100 can be disposed at the distal end of the sheath 300, and the distal end face of the flexible head 100 axially protrudes beyond the distal end face of the sheath 300. In this embodiment, when the flexible head 100 is disposed at the distal end of the sheath 300, the distal end face of the flexible head 100 axially protrudes beyond the distal end face of the sheath 300. That is, at least a portion of the flexible head 100 is located on the distal side of the sheath 300. Since the flexible head 100 is relatively soft, it is not easy to puncture human tissue, thus preventing damage to human tissue at the distal end of the sheath 300.

[0036] In a further embodiment, the sealing structure also includes a support member 200, which is an elastic or rigid structural member. The distal end of the support member 200 is fixedly connected to the flexible head 100 and extends toward the distal end face of the flexible head 100. The proximal end of the support member 200 can be fixedly connected to the sheath 300. In this embodiment, since the flexible head 100 needs to be interference-fitted with the expander 400, its inner circumferential surface will be pressed against the outer circumferential surface of the expander 400. Therefore, the support member 200 is located outside the inner circumferential surface of the flexible head 100, that is, at least a part of the flexible head 100 is located inside the support member 200. When the expander 400 is inserted into the flexible head 100, it will compress the flexible head 100 to deform outward. Since the support member 200 is an elastic or rigid structural member, it has a certain rigidity. Therefore, the support member 200 can constrain the flexible head 100 and keep it always against the outer circumferential surface of the expander 400, preventing gaps from forming between the flexible head 100 and the expander 400 that could trap human tissue. Furthermore, when the support member 200 is an elastic structural member, the support member 200 can also apply a compressive force to the flexible head 100 through its own elasticity, keeping it always against the outer circumferential surface of the expander 400. In addition, the support member 200 can also support the flexible head 100, thereby preventing the flexible head 100 from deforming under the pressure of the human body cavity, and thus preventing the flexible head 100 from forming a gap with the expander 400 after deformation and clamping the human tissue.

[0037] Optionally, the proximal end of the support member 200 can be embedded within the sheath tube 300 or attached to the outer peripheral surface of the sheath tube 300; the proximal end of the support member 200 can be bonded or welded to the distal end of the sheath tube 300; the distal end of the support member 200 can be bonded to the flexible head 100, or the distal end of the support member 200 can be integrally injection molded with the flexible head 100. In the case where the sealing structure only includes the flexible head 100, the flexible head 100 can be bonded to the distal end of the sheath tube 300.

[0038] In one alternative embodiment, please refer to Figure 2The distal end of the support member 200 is embedded inside the flexible head 100, and there is a predetermined distance between the distal end face of the support member 200 and the distal end face of the flexible head 100. In this embodiment, the distal end of the support member 200 is embedded inside the flexible head 100, meaning that the distal end of the support member 200 is not exposed outside the flexible head 100, thus preventing the distal end of the flexible head 100 from scratching human tissue. Furthermore, the predetermined distance between the distal end face of the support member 200 and the distal end face of the flexible head 100 means that the distal end of the support member 200 does not extend to the distal end face of the flexible head 100, thus allowing the distal end of the flexible head 100 to have lower rigidity, preventing the support member 200 from extending to the distal end face of the flexible head 100 and making the distal end of the flexible head 100 too hard, thereby preventing damage to human tissue during insertion into the human body. Of course, the distal end of the support member 200 can also be attached to the outer surface of the flexible head 100; this application does not limit this.

[0039] And / or, in an alternative embodiment, please refer to Figure 2 , 4 The support member 200 has a recessed portion 210, and a portion of the flexible head 100 is embedded in the recessed portion 210, so that the support member 200 and the flexible head 100 are engaged at the upper limit of the axial direction of the flexible head 100. In this embodiment, the support member 200 has a recessed portion 210, and a portion of the flexible head 100 is embedded in the recessed portion 210. This portion of the flexible head 100 is engaged with the support member 200 at the upper limit of the axial direction, which can prevent the flexible head 100 from separating from the support member 200 when subjected to axial force. Optionally, the recessed portion 210 may penetrate the support member 200 or may not penetrate the support member 200.

[0040] After the sheath 300 is inserted into the human body, in some cases the surgeon may insert the endoscope insertion section through the sheath 300 and exit from the distal end of the sheath 300. Because the support 200 increases the stiffness of the flexible head 100, this can hinder the bending of the endoscope insertion section to some extent, thus limiting its flexibility. To solve this problem, and / or, in an alternative embodiment, please refer to... Figure 6The flexible head 100 is a ring structure. The support member 200 extends circumferentially along the flexible head 100. The support member 200 is provided with an avoidance notch 220. The avoidance notch 220 passes through the support member 200 along the axial direction of the flexible head 100. The avoidance notch 220 is located on the curved path of the endoscope insertion part. A part of the flexible head 100 is embedded in the avoidance notch 220. In this embodiment, the support member 200 is provided with an avoidance notch 220. The avoidance notch 220 penetrates the support member 200 along the axial direction of the flexible head 100, and extends from the outer surface of the support member 200 to the inner surface of the support member 200. Therefore, the portion of the support member 200 with the avoidance notch 220 does not increase the rigidity of the flexible head 100. This allows the portion of the flexible head 100 corresponding to the avoidance notch 220 to have better flexibility. The avoidance notch 220 is located on the bending path of the endoscope insertion part. That is to say, the endoscope insertion part will contact the portion of the flexible head 100 corresponding to the avoidance notch 220 during the bending process. Since this portion has better flexibility, it can ensure good bending flexibility when the endoscope insertion part contacts this portion. It should be noted that the number of clearance notches 220 can be one or at least two. When there are at least two clearance notches 220, the support member 200 is divided into at least two segments by the clearance notches 220. Of course, the support member 200 can also be a ring structure, and this application does not limit this.

[0041] In one alternative embodiment, please refer to Figure 3 The support member 200 is an elastic structural member. The proximal end of the support member 200 extends axially along the sheath 300. In the direction extending from the proximal end to the distal end of the support member 200, the length of the support member 200 extending on the flexible head 100 is 'a', and the total length of the support member 200 is 'b', where a ≤ 1 / 2b. In this embodiment, the proximal end of the support member 200 extends axially along the sheath 300, and the distal end of the support member 200 extends toward the distal end face of the flexible head 100. That is, the portion of the support member 200 extending beyond the distal end of the sheath 300 coincides with the flexible head 100, while the portion of the support member 200 not extending beyond the distal end of the sheath 300 coincides with the distal end of the sheath 300. The length of the portion of the support member 200 extending at the distal end of the sheath 300 is 'c', and the length of the support member 200 extending on the flexible head 100 is 'a'. The total length of 0 is b, and a + c = b. Since a ≤ 1 / 2b, a ≤ c. That is, the length of the portion of the support member 200 extending beyond the distal end of the sheath 300 is less than the length of the portion of the support member 200 not extending beyond the distal end of the sheath 300. This allows the portion of the support member 200 extending beyond the distal end of the sheath 300 to have greater rigidity, preventing the distal end of the support member 200 from warping outward under axial force, thereby preventing the support member 200 from causing the flexible head 100 to warp outward and create a gap between it and the expander 400. Of course, the relationship between a and b can also be a > 1 / 2b, and this application does not limit this.

[0042] In one alternative embodiment, please refer to Figure 3 The distal end of the support member 200 is embedded inside the flexible head 100. The support member 200 divides the flexible head 100 into a first part 110 and a second part 120, which are distributed sequentially from the inside to the outside. The thickness of the first part 110 is greater than the thickness of the second part 120. In this embodiment, the thickness of the first part 110 is greater than the thickness of the second part 120. That is, the support member 200 is located on the outer part of the flexible head 100 from the inside to the outside. This allows a larger portion of the flexible head 100 to be distributed on the inner side of the support member 200, which gives the portion of the flexible head 100 located on the inner side of the support member 200 better deformability, thereby making the interference fit between the flexible head 100 and the expander 400 more reliable.

[0043] In one alternative embodiment, please refer to Figure 3 The flexible head 100 can be located at the distal end of the sheath 300. The proximal end of the inner surface of the flexible head 100 has a guide surface 130. In the direction extending from the proximal end to the distal end of the flexible head 100, the distance between the guide surface 130 and the axis of the flexible head 100 gradually decreases. The expander 400 can slide into the flexible head 100 through the guide surface 130. In this embodiment, generally speaking, the expander 400 is inserted from the proximal end of the flexible head 100 and exits from the distal end of the flexible head 100. Therefore, when the expander 400 is inserted, the distal end of the expander 400 will first contact the proximal end of the guide surface 130. The distance between the guide surface 130 and the axis of the flexible head 100 gradually decreases in the direction extending from the proximal end to the distal end of the flexible head 100. This allows the expander 400 to be gradually guided into the flexible head 100 for easy insertion. Optionally, the guide surface 130 can be an inclined surface, an arc surface, a frustum-shaped surface, etc.

[0044] In one alternative embodiment, please continue to refer to Figure 3The proximal end face of the flexible head 100 is in contact with the distal end face of the sheath 300. The guide surface 130 extends to the proximal end face of the flexible head 100 and extends circumferentially along the flexible head 100. An avoidance space 140 is formed between the guide surface 130 and the distal end face of the sheath 300. In this embodiment, the guide surface 130 extends to the proximal end face of the flexible head 100, and a clearance space 140 is formed between the guide surface 130 and the distal end face of the sheath 300. There is no solid part of the flexible head 100 in the clearance space 140. That is to say, a part of the solid part of the inner side of the proximal end of the flexible head 100 can be removed by the guide surface 130, thereby forming the aforementioned clearance space 140 on the inner side of the proximal end of the flexible head 100. In this way, when the distal end of the flexible head 100 is resisted, the flexible head 100 can be tilted and deformed from the outside to the inside, so that the flexible head 100 can hug the expander 400 to improve the sealing effect of the flexible head 100.

[0045] In one alternative embodiment, please refer to Figure 1 , 3 4, 5, 6. The flexible head 100 can be located at the distal end of the sheath 300. The distal end face of the flexible head 100 axially protrudes beyond the distal end face of the sheath 300, and the outer peripheral surface of the flexible head 100 radially protrudes beyond the outer peripheral surface of the sheath 300. In this embodiment, the outer peripheral surface of the flexible head 100 radially protrudes beyond the outer peripheral surface of the sheath 300. That is, in the direction extending from the flexible head 100 to the sheath 300, the flexible head 100 covers the sheath 300. In this way, during the insertion of the guide sheath, the distal end of the sheath 300 can be prevented from contacting the human tissue first, and instead, the flexible head 100 can contact the human tissue first. Since the flexible head 100 has good flexibility, this can prevent the guide sheath from damaging the human tissue. Of course, the outer peripheral surface of the flexible head 100 can also be flush with the outer peripheral surface of the sheath 300, or the outer peripheral surface of the sheath 300 can also radially protrude beyond the outer peripheral surface of the flexible head 100.

[0046] This application also discloses a guide sheath component, including the sealing structure described in any of the above embodiments. The guide sheath component is a sheath tube 300 or an expander 400. Optionally, the sheath tube 300 may include a curved portion 320, a main body portion 310, and a skin 330 sequentially sleeved from the inside out.

[0047] Since the guide sheath component of this application includes the sealing structure of any of the above embodiments, the guide sheath component of this application also has the function of the sealing structure described above. For the sake of brevity, this application will not elaborate further.

[0048] like Figure 7 As shown in the illustration, this application also discloses a guide sheath, including the sealing structure described in any of the above embodiments. Optionally, the guide sheath may further include an operating handle 600.

[0049] Since the guide sheath of this application includes the sealing structure of any of the above embodiments, the guide sheath of this application also has the function of the sealing structure described above. For the sake of brevity, this application will not elaborate further.

[0050] The foregoing embodiments of this application focus on describing the differences between various embodiments. As long as the different optimization features between embodiments are not contradictory, they can be combined to form better embodiments. For the sake of brevity, these differences will not be elaborated upon here. The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art, under the guidance of this application, can make many modifications without departing from the spirit and scope of the claims, all of which fall within the protection scope of this application.

Claims

1. A sealing structure for a guide sheath, characterized in that, The sealing structure includes a flexible head (100). The flexible head (100) can be disposed at the distal end of the sheath (300), the inner circumferential surface of the flexible head (100) protrudes radially from the inner circumferential surface of the sheath (300), the flexible head (100) can be sleeved outside the expander (400) and can be interference-fitted with the expander (400) to seal at least a portion of the gap (500) between the distal end of the sheath (300) and the expander (400); The sealing structure also includes a support member (200), which is an elastic or rigid structural member. The distal end of the support member (200) is fixedly connected to the flexible head (100) and extends toward the distal end face of the flexible head (100). The proximal end of the support member (200) can be fixedly connected to the sheath (300).

2. The sealing structure according to claim 1, characterized in that, The flexible head (100) can be disposed at the distal end of the sheath (300), and the distal end face of the flexible head (100) axially protrudes beyond the distal end face of the sheath (300).

3. The sealing structure according to claim 2, characterized in that, The distal end of the support member (200) is embedded inside the flexible head (100), and there is a preset distance between the distal end face of the support member (200) and the distal end face of the flexible head (100); and / or, The support member (200) has a recess (210), and a portion of the flexible head (100) is embedded in the recess (210) so that the support member (200) and the flexible head (100) are in axial upper limit engagement; and / or, The flexible head (100) is a ring structure. The support member (200) extends circumferentially along the flexible head (100). The support member (200) is provided with a clearance notch (220). The clearance notch (220) passes through the support member (200) along the axial direction of the flexible head (100). The clearance notch (220) is located on the curved path of the endoscope insertion part. A part of the flexible head (100) is embedded in the clearance notch (220).

4. The sealing structure according to claim 2 or 3, characterized in that, The support member (200) is an elastic structural member. The proximal end of the support member (200) extends along the axial direction of the sheath (300). In the direction extending from the proximal end of the support member (200) to the distal end, the length of the support member (200) extending on the flexible head (100) is a, and the total length of the support member (200) is b, where a ≤ 1 / 2b.

5. The sealing structure according to claim 2 or 3, characterized in that, The distal end of the support member (200) is embedded inside the flexible head (100). The support member (200) divides the flexible head (100) into a first part (110) and a second part (120). The first part (110) and the second part (120) are distributed from the inside to the outside. The thickness of the first part (110) is greater than the thickness of the second part (120).

6. The sealing structure according to any one of claims 1 to 3, characterized in that, The flexible head (100) can be disposed at the distal end of the sheath (300). The proximal end of the inner surface of the flexible head (100) has a guide surface (130). In the direction extending from the proximal end to the distal end of the flexible head (100), the distance between the guide surface (130) and the axis of the flexible head (100) gradually decreases. The expander (400) can slide into the flexible head (100) through the guide surface (130).

7. The sealing structure according to claim 6, characterized in that, The proximal end face of the flexible head (100) is in contact with the distal end face of the sheath (300), the guide surface (130) extends to the proximal end face of the flexible head (100), and the guide surface (130) extends circumferentially along the flexible head (100). A clearance space (140) is formed between the guide surface (130) and the distal end face of the sheath (300).

8. The sealing structure according to any one of claims 1 to 3, characterized in that, The flexible head (100) can be disposed at the distal end of the sheath (300), the distal end face of the flexible head (100) axially protrudes from the distal end face of the sheath (300), and the outer peripheral surface of the flexible head (100) radially protrudes from the outer peripheral surface of the sheath (300).

9. A guide sheath component, characterized in that, The sealing structure includes any one of claims 1 to 8, wherein the guiding sheath component is a sheath tube (300) or an expander (400).

10. A guiding sheath, characterized in that, Includes the sealing structure as described in any one of claims 1 to 8.

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