Guide sheath component, guide sheath, and sealing structure thereof

Abstract

Provided are a guide sheath component, a guide sheath, and a sealing structure thereof. The sealing structure comprises a flexible head (100). The flexible head (100) can be arranged at a distal end of a sheath tube (300), an inner circumferential surface of the flexible head (100) radially protrudes from an inner circumferential surface of the sheath tube (300), and the flexible head (100) may sheathe a dilator (400) and is in interference fit with the dilator (400), so as to seal at least part of a gap (500) between the distal end of the sheath tube (300) and the dilator (400). Alternatively, the flexible head (100) may sheathe a distal end of the dilator (400), an outer circumferential surface of the flexible head (100) radially protrudes from an outer circumferential surface of the dilator (400), and the flexible head (100) can be in contact with the distal end of the sheath tube (300), so as to seal at least part of the gap (500) between the distal end of the sheath tube (300) and the dilator (400), thereby preventing the luminal tissue of a human body from entering the gap (500) and being clamped, and solving the problem of stress response of a patient due to the tearing of the luminal tissue.

Description

Guide sheath component, guide sheath and sealing structure thereof Technical Field

[0001] The present application belongs to the technical field of medical devices, and specifically relates to a guide sheath component, a guide sheath and a sealing structure thereof. Background Art

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

[0003] However, clinically, patients often experience significant stress reactions when the surgeon inserts the introducer sheath into the ureter. Therefore, how to prevent patients from experiencing stress reactions during the insertion of the introducer sheath is a technical issue that needs to be addressed urgently by those skilled in the art. Summary of the Invention

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

[0005] In order to solve the above technical problems, this application is implemented as follows:

[0006] In a first aspect, an embodiment of the present application provides a sealing structure of an introducer sheath, the sealing structure comprising a flexible head,

[0007] Wherein, the flexible head can be arranged at the distal end of the sheath tube, the inner circumference of the flexible head radially protrudes from the inner circumference of the sheath tube, the flexible head can be sleeved outside the dilator and can have an interference fit with the dilator to seal at least part of the gap between the distal end of the sheath tube and the dilator; or,

[0008] The flexible head can be sleeved on the distal end of the dilator, with its outer circumference radially protruding from that of the dilator. The flexible head can contact the distal end of the sheath to seal at least part of the gap between the distal end of the sheath and the dilator.

[0009] In a second aspect, an embodiment of the present application provides a guide sheath component, including the above-mentioned sealing structure, wherein the guide sheath component is a sheath tube or a dilator.

[0010] In a third aspect, an embodiment of the present application provides a guide sheath comprising the above-mentioned sealing structure.

[0011] In an embodiment of the present application, the sealing structure includes a flexible head. When the sealing structure of the present application is specifically used, the flexible head can be arranged at the distal end of the sheath or can be sleeved on the distal end of the dilator. When the flexible head is arranged at the distal end of the sheath, the inner circumference of the flexible head radially protrudes from the inner circumference of the sheath. Therefore, after the dilator is inserted into the flexible head, the dilator will have an interference fit with the flexible head, thereby sealing the gap between the distal end of the sheath and the dilator, thereby preventing the human body's cavity tissue from entering the gap and being clamped.

[0012] When the flexible head is sleeved on the distal end of the dilator, the outer peripheral surface of the flexible head radially protrudes from the outer peripheral surface of the dilator, and the flexible head can contact the distal end of the sheath to seal the gap between the distal end of the sheath and the dilator. This can also prevent the human body's cavity tissue from entering the gap between the distal end of the sheath and the dilator and being clamped.

[0013] From the above analysis, it can be seen that the sealing structure of the present application can prevent the body's cavity tissue from entering the gap between the distal end of the sheath and the expander, which can avoid the sheath and the expander clamping the cavity tissue, thereby solving the problem of the cavity tissue being torn and causing the patient to have a stress reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG1 is a schematic diagram of the assembly of the sealing structure and the sheath tube disclosed in an embodiment of the present application and an enlarged schematic diagram of point A therein;

[0015] FIG2 is an exploded schematic diagram of the sealing structure and sheath tube disclosed in an embodiment of the present application;

[0016] FIG3 is a cross-sectional view of the assembled sealing structure and sheath tube disclosed in an embodiment of the present application;

[0017] FIG4 is a longitudinal cross-sectional view of the sealing structure disclosed in an embodiment of the present application;

[0018] FIG5 is a cross-sectional view of the assembled sealing structure, sheath, and dilator disclosed in an embodiment of the present application;

[0019] FIG6 is a cross-sectional view of a sealing structure disclosed in another embodiment of the present application;

[0020] FIG7 is a schematic diagram of the structure of the guide sheath disclosed in an embodiment of the present application and an enlarged schematic diagram of point B therein.

[0021] Description of reference numerals:

[0022] 100. Flexible head; 110. First part; 120. Second part; 130. Guide surface; 140. Avoidance space; 200. Support member; 210. Recessed part; 220. Avoidance notch; 300. Sheath; 310. Main body; 320. Bend; 330. Skin; 400. Dilator; 500. Gap; 600. Operating handle. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0024] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0025] The guide sheath component, the guide sheath and the sealing structure thereof provided in the embodiments of the present application are described in detail below with reference to specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0026] In each embodiment of the present application, "proximal end" and "distal end" refer to the position of the guide sheath and its components relative to the user in the use environment, wherein 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] Generally speaking, an introducer sheath includes a sheath tube and a dilator. When inserting the introducer sheath, the sheath tube needs to be sleeved onto the outside of the dilator so that the sheath tube can be inserted into the ureter under the guidance of the dilator. After the introducer sheath reaches the predetermined position, the dilator can be withdrawn from the sheath tube. The inventors have discovered that after the sheath tube is sleeved onto the outside of the dilator, a gap exists between the distal end of the sheath tube and the dilator. Therefore, when the introducer sheath is inserted, the body's cavity tissue may be squeezed into this gap and thus clamped by the sheath tube and dilator. Further insertion of the introducer sheath will cause the part of the cavity tissue to be torn, which obviously causes a stress reaction in the patient.

[0028] As shown in Figures 1 to 6, the embodiment of the present application discloses a sealing structure of an introducer sheath, which includes a flexible head 100. Optionally, the flexible head 100 can be made of a polymer medical-grade soft material such as silicone rubber.

[0029] The flexible head 100 can be disposed at the distal end of the sheath 300, and the inner circumferential surface of the flexible head 100 radially protrudes from the inner circumferential surface of the sheath 300. The flexible head 100 can be sleeved outside the dilator 400 and can be interference-fitted with the dilator 400 to seal at least a portion of the gap 500 between the distal end of the sheath 300 and the dilator 400. In other words, the flexible head 100 can seal at least a portion of the gap 500 in its own circumferential direction. In this embodiment of the present application, the inner circumferential surface of the flexible head 100 radially protrudes from the inner circumferential surface of the sheath 300. Therefore, after the dilator 400 is inserted into the flexible head 100, the dilator 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 dilator 400, thereby preventing the body's cavity tissue from entering the gap 500 and being clamped.

[0030] Optionally, after the dilator 400 passes through the assembled whole of the flexible head 100 and the sheath 300, at least a portion of the flexible head 100 may be located in the gap 500 between the dilator 400 and the sheath 300. At this time, 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 exceeds the distal end face of the sheath 300, thereby sealing the gap 500; or, all portions of the flexible head 100 may also be located outside the gap 500 between the dilator 400 and the sheath 300 (as shown in Figure 5). 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 may also seal the gap 500. The present application does not limit the setting position of the flexible head 100, as long as the following conditions are met: after the expander 400 passes through the assembled whole of the flexible head 100 and the sheath 300, the flexible head 100 can seal at least part 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 part of the gap 500 in its own circumferential direction from being connected to the space outside the gap 500.

[0031] Alternatively, the flexible head 100 can be sleeved on the distal end of the dilator 400, with the outer circumferential surface of the flexible head 100 radially protruding from the outer circumferential surface of the dilator 400. That is, the flexible head 100 is sleeved on the outside of the distal end of the dilator 400, and the flexible head 100 can contact the distal end of the sheath tube 300 to seal at least a portion of the gap 500 between the distal end of the sheath tube 300 and the dilator 400. That is, the flexible head 100 can seal at least a portion of the gap 500 in its own circumferential direction. In the embodiment of the present application, the outer circumferential surface of the flexible head 100 radially protrudes from the outer circumferential surface of the dilator 400, and the flexible head 100 can contact the distal end of the sheath tube 300 to seal the gap 500 between the distal end of the sheath tube 300 and the dilator 400. This can also prevent the body's cavity tissue from entering the gap 500 and being clamped.

[0032] Similarly, after the expander 400 passes through the assembled 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 circumference 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 the distal end face of the sheath 300, which will not be further elaborated in this application.

[0033] It should be noted that the interior of the flexible head 100 is provided with a sleeve space that penetrates along its own axial direction, so that it can be sleeved outside the expander 400; the flexible head 100 can be an annular structural part, in which case the flexible head 100 can completely seal the above-mentioned gap 500, that is: it can seal all parts of the above-mentioned gap 500 in its own circumferential direction; or the flexible head 100 can also be an arc-shaped structural part, in which case the flexible head 100 seals a part of the above-mentioned gap 500 in its own circumferential direction.

[0034] The axial direction mentioned above is the direction shown by the x-arrow line in FIG. 3 , and the radial direction is the direction perpendicular to the x-arrow line, such as the directions shown by the y-arrow line and the z-arrow line in FIG. 3 .

[0035] In an optional embodiment, the flexible head 100 can be disposed at the distal end of the sheath tube 300, and the distal end surface of the flexible head 100 axially protrudes from the distal end surface of the sheath tube 300. In this embodiment, when the flexible head 100 is disposed at the distal end of the sheath tube 300, the distal end surface of the flexible head 100 axially protrudes from the distal end surface of the sheath tube 300. In other words, at least a portion of the flexible head 100 is located on the distal side of the sheath tube 300. Since the flexible head 100 is relatively soft, it is not easy to pierce human tissue, thereby preventing the distal end of the sheath tube 300 from damaging human tissue.

[0036] In a further embodiment, the sealing structure also includes a support member 200, which is an elastic structural member or a 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, and the proximal end of the support member 200 can be fixedly connected to the sheath tube 300. In this embodiment, since the flexible head 100 needs to have an interference fit with the expander 400, its inner circumference will be squeezed and fitted with the outer circumference of the expander 400, so the support member 200 is located on the outside of the inner circumference of the flexible head 100, that is, at least part of the flexible head 100 is located on the inner side of the support member 200; when the expander 400 is inserted into the flexible head 100, it will squeeze the flexible head 100 to deform outward, and since the support member 200 is an elastic structural member or a rigid structural member, it has a certain rigidity, so the support member 200 can restrain the flexible head 100 and make it always stick to the outer circumference of the expander 400, preventing the formation of a gap between the flexible head 100 and the expander 400 to clamp human tissue; and, in the case that the support member 200 is an elastic structural member, the support member 200 can also apply an extrusion force to the flexible head 100 through its own elasticity, so that it always sticks to the outer circumference of the expander 400. In addition, the support member 200 can also support the flexible head 100, thereby preventing the flexible head 100 from being deformed under the squeeze of the human body cavity, thereby preventing the flexible head 100 from forming a gap with the expander 400 after deformation and clamping human tissue.

[0037] Alternatively, the proximal end of the support member 200 may be embedded in the sheath tube 300 or attached to the outer circumference of the sheath tube 300, and the proximal end of the support member 200 may be bonded or welded to the distal end of the sheath tube 300; the distal end of the support member 200 may be bonded to the flexible head 100, or the distal end of the support member 200 may 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 may be bonded to the distal end of the sheath tube 300.

[0038] In an optional embodiment, referring to FIG2 , the distal end of the support member 200 is embedded in the interior of the flexible head 100, and a preset distance is provided between the distal end surface of the support member 200 and the distal end surface of the flexible head 100. In this embodiment, the distal end of the support member 200 is embedded in the interior of the flexible head 100, that is, the distal end of the support member 200 is not exposed outside the flexible head 100, thereby preventing the distal end of the flexible head 100 from scratching human tissue; in addition, a preset distance is provided between the distal end surface of the support member 200 and the distal end surface of the flexible head 100, that is, the distal end of the support member 200 does not extend to the distal end surface of the flexible head 100, thereby making the distal end of the flexible head 100 less hard, thereby preventing the support member 200 from extending to the distal end surface of the flexible head 100 and causing the distal end of the flexible head 100 to be too hard, thereby preventing the flexible head 100 from damaging human tissue during insertion into the human body. Of course, the distal end of the support member 200 may also be attached to the outer surface of the flexible head 100 , and this application is not limited to this.

[0039] And / or, in an optional embodiment, referring to Figures 2 and 4, a recessed portion 210 is provided on the support member 200, 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 cooperate at the axial upper limit position of the flexible head 100. In this embodiment, the recessed portion 210 is provided on the support member 200, and a portion of the flexible head 100 is embedded in the recessed portion 210. This portion of the flexible head 100 cooperates with the support member 200 at the axial upper limit position, thereby preventing the flexible head 100 from separating from the support member 200 when subjected to an axial force. Optionally, the recessed portion 210 may or may not penetrate the support member 200.

[0040] After inserting the sheath 300 into the human body, in some cases, the surgeon may insert the endoscope insertion portion through the sheath 300 and pass it out from the distal end of the sheath 300. Since the support member 200 increases the rigidity of the flexible head 100, this will hinder the bending of the endoscope insertion portion to a certain extent, thereby limiting the bending flexibility of the endoscope insertion portion. To solve this problem, and / or, in an optional embodiment, please refer to Figure 6, the flexible head 100 is an annular structural member, the support member 200 extends along the circumference of the flexible head 100, and 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 the avoidance notch 220 is located on the curved path of the endoscope insertion portion, and a portion of the flexible head 100 is embedded in the avoidance notch 220. In this embodiment, an avoidance notch 220 is provided on the support member 200, and the avoidance notch 220 penetrates the support member 200 along the axial direction of the flexible head 100, and the avoidance notch 220 passes through the support member 200 from the outer surface of the support member 200 to the inner surface of the support member 200. Therefore, the part of the support member 200 provided with the avoidance notch 220 does not increase the rigidity of the flexible head 100, which can make the part of the flexible head 100 corresponding to the avoidance notch 220 have better flexibility, and the avoidance notch 220 is located on the bending path of the endoscope insertion part, that is, the endoscope insertion part will contact the part of the flexible head 100 corresponding to the avoidance notch 220 during the bending process. Since this part has good flexibility, it can be guaranteed to have good bending flexibility when the endoscope insertion part contacts this part. It should be noted that the number of the avoidance notch 220 can be one or at least two. When there are at least two avoidance notches 220, the support member 200 is divided into at least two sections by the avoidance notches 220. Of course, the support member 200 can also be an annular structural member, which is not limited in this application.

[0041] In an optional embodiment, please refer to Figure 3, 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 tube 300, and 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, and a≤1 / 2b. In this embodiment, the proximal end of the support member 200 extends along the axial direction of the sheath tube 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 out of the distal end of the sheath tube 300 overlaps with the flexible head 100, and the portion of the support member 200 not extending out of the distal end of the sheath tube 300 overlaps with the distal end of the sheath tube 300, the length of the portion of the support member 200 extending at the distal end of the sheath tube 300 is c, the length of the support member 200 extending on the flexible head 100 is a, and the length of the support member 200 extending on the flexible head 100 is 0 is b, a+c=b. Since a≤1 / 2b, a≤c, that is, the length of the portion of the support member 200 extending from the distal end of the sheath tube 300 is less than the length of the portion of the support member 200 not extending from the distal end of the sheath tube 300. This allows the portion of the support member 200 extending from the distal end of the sheath tube 300 to have greater rigidity, thereby preventing the distal end of the support member 200 from warping outward when subjected to an axial force, thereby preventing the support member 200 from causing the flexible head 100 to warp outward and creating a gap between the support member 200 and the dilator 400. Of course, the relationship between a and b can also be: a>1 / 2b, and this application is not limited to this.

[0042] In an optional embodiment, referring to FIG3 , the distal end of the support member 200 is embedded within the flexible head 100. The support member 200 divides the flexible head 100 into a first portion 110 and a second portion 120. The first portion 110 and the second portion 120 are arranged sequentially from the inside to the outside, and the thickness of the first portion 110 is greater than the thickness of the second portion 120. In this embodiment, the thickness of the first portion 110 is greater than the thickness of the second portion 120. In other words, the support member 200 is arranged at a position closer to the outside 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. This allows the portion of the flexible head 100 located on the inner side of the support member 200 to have greater deformability, thereby making the interference fit between the flexible head 100 and the expander 400 more reliable.

[0043] In an alternative embodiment, referring to FIG3 , 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 includes a guide surface 130. The distance between the guide surface 130 and the axis of the flexible head 100 gradually decreases as it extends from the proximal end to the distal end of the flexible head 100. The dilator 400 can slide into the flexible head 100 through the guide surface 130. In this embodiment, generally, the dilator 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 dilator 400 is inserted, the distal end of the dilator 400 first contacts 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 as it extends from the proximal end to the distal end of the flexible head 100. This allows the dilator 400 to be gradually guided into the flexible head 100, facilitating insertion. Optionally, the guide surface 130 may be an inclined surface, a curved surface, a frustum surface, etc.

[0044] In an optional embodiment, please continue to refer to Figure 3, the proximal end face of the flexible head 100 is in contact with the distal end face of the sheath tube 300, the guide surface 130 extends to the proximal end face of the flexible head 100, and the guide surface 130 extends along the circumference of the flexible head 100, and an avoidance space 140 is formed between the guide surface 130 and the distal end face of the sheath tube 300. In this embodiment, the guide surface 130 extends to the proximal end surface of the flexible head 100, and an avoidance space 140 is formed between the guide surface 130 and the distal end surface of the sheath tube 300. There is no solid part of the flexible head 100 in the avoidance space 140. That is, a part of the solid body on the inner side of the proximal end of the flexible head 100 can be removed through the guide surface 130, thereby forming the above-mentioned avoidance 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 encounters resistance, the flexible head 100 can be tilted and deformed from the outside to the inside, so that the flexible head 100 can hold the expander 400 tightly to enhance the sealing effect of the flexible head 100.

[0045] In an alternative embodiment, referring to Figures 1, 3, 4, 5, and 6, the flexible head 100 can be disposed at the distal end of the sheath tube 300, with the distal end surface of the flexible head 100 axially protruding from the distal end surface of the sheath tube 300, and the outer circumference of the flexible head 100 radially protruding from the outer circumference of the sheath tube 300. In this embodiment, the outer circumference of the flexible head 100 radially protrudes from the outer circumference of the sheath tube 300. That is, in the direction extending from the flexible head 100 to the sheath tube 300, the flexible head 100 covers the sheath tube 300. In this way, during the insertion of the guide sheath, the distal end of the sheath tube 300 is prevented from contacting human tissue first, and the flexible head 100 is caused to contact human tissue first. Due to the good flexibility of the flexible head 100, this prevents the guide sheath from damaging human tissue. Of course, the outer circumference of the flexible head 100 can also be flush with the outer circumference of the sheath tube 300, or the outer circumference of the sheath tube 300 can also radially protrude from the outer circumference of the flexible head 100.

[0046] The present application also discloses a guide sheath component, including the sealing structure described in any of the above embodiments, wherein the guide sheath component is a sheath tube 300 or a dilator 400. Optionally, the sheath tube 300 may include a curved portion 320, a main body 310, and a skin 330 sequentially arranged from the inside to the outside.

[0047] Since the guide sheath component of the present application includes the sealing structure of any of the above embodiments, the guide sheath component of the present application also has the function of the above sealing structure, and for the sake of brevity, this application will not elaborate on it.

[0048] As shown in FIG7 , the present application also discloses an introducer sheath, comprising the sealing structure described in any of the above embodiments. Optionally, the introducer sheath may further comprise an operating handle 600 .

[0049] Since the guide sheath of the present application includes the sealing structure of any of the above embodiments, the guide sheath of the present application also has the functions of the above sealing structure, and for the sake of brevity, this application will not elaborate on it.

[0050] The above embodiments of the present application focus on 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. Considering the simplicity of the text, they will not be repeated here. The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of this application and the claims, all of which are within the protection of this application.

Claims

1. A sealing structure of an introducer sheath, characterized in that: The sealing structure comprises a flexible head (100), The flexible head (100) can be arranged at the distal end of the sheath tube (300), the inner circumferential surface of the flexible head (100) radially protrudes from the inner circumferential surface of the sheath tube (300), and the flexible head (100) can be sleeved outside the dilator (400) and can be interference-fitted with the dilator (400) to seal at least part of the gap (500) between the distal end of the sheath tube (300) and the dilator (400); or, The flexible head (100) can be sleeved on the distal end of the dilator (400), and the outer peripheral surface of the flexible head (100) radially protrudes from the outer peripheral surface of the dilator (400). The flexible head (100) can contact the distal end of the sheath (300) to seal at least part of the gap (500) between the distal end of the sheath (300) and the dilator (400).

2. The sealing structure according to claim 1, wherein: The flexible head (100) can be arranged at the distal end of the sheath tube (300), and the distal end surface of the flexible head (100) protrudes axially from the distal end surface of the sheath tube (300); The sealing structure further comprises a support member (200), wherein the support member (200) is an elastic structural member or a rigid structural member, wherein 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), and the proximal end of the support member (200) can be fixedly connected to the sheath tube (300).

3. The sealing structure according to claim 2, characterized in that: The distal end of the support member (200) is embedded in the interior of the flexible head (100), and a preset distance exists between the distal end surface of the support member (200) and the distal end surface of the flexible head (100); and / or, The support member (200) is provided with 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) cooperate with each other at the axial upper limit position of the flexible head (100); and / or, The flexible head (100) is an annular structural member, the support member (200) extends along the circumference of the flexible head (100), and a relief notch (220) is provided on the support member (200). The relief notch (220) penetrates the support member (200) along the axial direction of the flexible head (100), and the relief notch (220) is located on a curved path of an insertion portion of an endoscope, and a portion of the flexible head (100) is embedded in the relief 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 tube (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.

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

6. The sealing structure according to any one of claims 1 to 3, characterized in that: The flexible head (100) can be arranged at the distal end of the sheath (300), and 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, and the dilator (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 tube (300), the guide surface (130) extends to the proximal end face of the flexible head (100), and the guide surface (130) extends along the circumference of the flexible head (100), and an avoidance space (140) is formed between the guide surface (130) and the distal end face of the sheath tube (300).

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

9. A guide sheath component, characterized in that: It comprises the sealing structure according to any one of claims 1 to 8, wherein the guide sheath component is a sheath tube (300) or a dilator (400).

10. An introducer sheath, characterized in that: The invention comprises the sealing structure according to any one of claims 1 to 8.

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