Vacuum suction sheath

Abstract

The present application belongs to the field of medical device technology, and specifically relates to a negative pressure suction sheath. The negative pressure suction sheath includes a sheath tube and a blocking structure. The sheath tube is arranged at the distal end of the negative pressure suction sheath. The distal end of the sheath tube has a passive bending section that can bend following the active bending section of the endoscope. The side wall of the passive bending section is provided with a through-hole, and the through-hole extends along the extension direction of the passive bending section. The maximum depth of the through-hole is less than half of the outer diameter of the passive bending section. The blocking structure is connected to the sheath tube and seals the through-hole; the passive bending section includes an expandable portion arranged radially opposite to the through-hole. When the passive bending section is bent and the side of the expandable portion away from the through-hole is the stretching side, the expandable portion expands outward in a direction perpendicular to the plane where the bending direction of the passive bending section is located. The present application can solve the problem that the stone discharge is not smooth when the distal end of the sheath tube is driven to bend by the insertion part to aspirate the lateral stones.

Description

Technical Field

[0001] The present application belongs to the field of medical device technology, and specifically relates to a negative pressure suction sheath. Background Art

[0002] Negative pressure suction sheaths are often used in urological endoscopic examinations or surgeries. They can establish a surgical channel in 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 examinations and treatments.

[0003] When using a negative pressure suction sheath to remove kidney stones, the sheath of the negative pressure suction sheath can be placed into the kidney using a guide wire, and then the insertion portion of the endoscope can be inserted into the sheath to observe and break up the stones. When the stone is on the side of the sheath, the insertion portion can be used to drive the distal end of the sheath to bend, so that the sheath is directed toward the stone and the stone is sucked into the gap between the insertion portion and the sheath, thereby expelling the stone. However, in practice, when the insertion portion is used to drive the distal end of the sheath to bend to suck the lateral stone, the problem of unsmooth stone removal is prone to occur. Summary of the invention

[0004] The purpose of the present application is to provide a negative pressure suction sheath, which can solve the problem of poor stone removal when the distal end of the sheath tube is bent by the insertion part to aspirate lateral stones.

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

[0006] The present application provides a negative pressure suction sheath, comprising a sheath tube and a blocking structure, wherein the sheath tube is arranged at the distal end of the negative pressure suction sheath, the distal end of the sheath tube has a passive bending section that can bend following the active bending section of an endoscope, the side wall of the passive bending section is provided with a through opening, the through opening extends along the extension direction of the passive bending section, the maximum depth of the through opening is less than half of the outer diameter of the passive bending section, and the blocking structure is connected to the sheath tube and seals the through opening;

[0007] The passive bending section includes an expandable portion radially arranged opposite to the through opening. When the passive bending section is bent and the side of the expandable portion away from the through opening is the stretching side, the expandable portion expands outward in a direction perpendicular to the plane where the bending direction of the passive bending section is located.

[0008] The beneficial technical effects of this application are as follows:

[0009] In the present application, a through hole is provided on the passive bending section, which will destroy the continuity of the passive bending section, causing stress concentration near the through hole when the passive bending section is bent, and the stress concentration area will be more easily deformed due to excessive local stress, so that the expandable portion radially opposite to the through hole expands outward in a direction perpendicular to the plane where the bending direction of the passive bending section is located, so as to release the stress accumulated when the passive bending section is bent. After the expandable portion expands radially outward, the distance between the inner wall of the expandable portion and the active bending section will be increased, thereby increasing the flow area there and increasing the minimum value of each maximum distance, so that the target object can smoothly pass through the gap between the curved active bending section and the curved passive bending section, thereby solving the problem of unsmooth discharge of stones while waiting for suction.

[0010] In addition, when the passive bending section of the present application does not follow the active bending section to bend, the portion of the blocking structure located at the through-hole will not be squeezed, so the blocking structure will not bulge toward the outside of the through-hole. That is to say, when the passive bending section is in a straight state, the outer diameters of various portions of the passive bending section in its own extension direction are relatively small, which is conducive to inserting the sheath into the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is an exploded schematic diagram of a partial structure of the guide sheath disclosed in the first embodiment of the present application;

[0012] Figure 2 It is an exploded schematic diagram of a part of the structure of the guide sheath when the passive bending section disclosed in the first embodiment of the present application is bent;

[0013] Figure 3 It is an exploded schematic diagram of a partial structure of the guide sheath disclosed in the second embodiment of the present application;

[0014] Figure 4 For this application Figure 3 The enlarged schematic diagram of point A in the middle;

[0015] Figure 5 It is an exploded schematic diagram of a part of the structure of the guide sheath when the passive bending section disclosed in the second embodiment of the present application is bent;

[0016] Figure 6 It is an exploded schematic diagram of a partial structure of the guide sheath disclosed in the third embodiment of the present application;

[0017] Figure 7 It is an exploded schematic diagram of a part of the structure of the guide sheath when the passive bending section disclosed in the third embodiment of the present application is bent;

[0018] Figure 8 This is a schematic diagram of the cooperation between the guide sheath and the insertion portion when the passive bending section disclosed in the third embodiment of the present application is bent;

[0019] Fig. 9 It is a schematic diagram of the cooperation between the curved sheath tube and the curved active bending section in the related art, and a schematic diagram of the cross section along the line a to the line g.

[0020] Description of reference numerals:

[0021] 100, sheath; 101, first section; 102, second section; 110, passive bending section; 111, through-hole; 1111, arc-shaped portion; 1112, connecting portion; 112, expandable portion; 113, supporting tongue; 200, blocking structure; 300, insertion portion; 310, active bending section. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0023] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0024] The negative pressure suction sheath provided in the embodiment of the present application is described in detail below through specific embodiments and their application scenarios in combination with the accompanying drawings.

[0025] In each embodiment of the present application, "proximal" and "distal" refer to the position of the negative pressure suction sheath and its components relative to the user in the use environment, wherein the end closer to the user is designated as the "proximal" and the end farther from the user is designated as the "distal".

[0026] like Fig. 9As shown, during the operation in which the insertion portion 300 and the sheath tube 100 are used together to remove stones and wait for the suction material, there is a suction gap between the endoscope insertion portion 300 and the inner wall of the sheath tube 100, so that the stones are discharged from the suction gap; of course, in order to facilitate the doctor to obtain the location of the stones, especially in the operation of kidney stone removal, the endoscope needs to be inserted into the renal calyx through the natural cavity or percutaneous kidney to remove stones in various areas of the renal calyx. Therefore, in order to avoid causing great trauma to the patient's kidneys, most endoscopes have a controllable bending function. Therefore, in order to adapt to the bending of the active bending section 310 of the endoscope insertion portion 300, the distal end of the sheath tube 100 adapted thereto in the prior art also has the ability of passive bending, that is, the active bending section 310 of the endoscope can drive the distal end of the sheath tube 100 to bend during the bending process.

[0027] The inventors discovered that, in actual surgical procedures, when the active bending section 310 drives the sheath tube 100 to be in a bent state, different parts of the active bending section 310 will press against specific positions of the sheath tube 100. Therefore, in the extension direction of the active bending section 310, the maximum distances between the various parts of the curved active bending section 310 in its own extension direction and the inner wall of the curved sheath tube 100 are unevenly distributed. In other words, the maximum distances between the various parts of the curved active bending section 310 in its own extension direction and the inner wall of the curved sheath tube 100 are constantly changing. Therefore, in the process of aspirating stones, stones whose size is equal to or slightly larger than the minimum value of the maximum distances may be blocked between the curved sheath tube 100 and the curved active bending section 310, resulting in poor stone removal.

[0028] Here, the maximum distance between each part of the curved active bending section 310 in its own extension direction and the inner wall of the curved sheath tube 100 is explained. Fig. 9 In views a to g, since the diameter of the active bending segment 310 is smaller than the diameter of the sheath tube 100, there must be a gap between the curved active bending segment 310 and the curved sheath tube 100, and the gap surrounds the curved active bending segment 310. Therefore, the distances between various circumferential regions of a part of the curved active bending segment 310 in its own extension direction and the inner wall of the sheath tube 100 are not equal, and the maximum value of the distances between various circumferential regions of this part of the curved active bending segment 310 and the sheath tube 100 is: the maximum distance between this part of the curved active bending segment 310 and the curved sheath tube 100.

[0029] like Figures 1 to 8As shown, the embodiment of the present application discloses a negative pressure suction sheath, including a sheath tube 100 and a blocking structure 200. The sheath tube 100 is arranged at the distal end of the negative pressure suction sheath, and the distal end of the sheath tube 100 has a passive bending section 110 that can bend following the active bending section 310 of the endoscope. Exemplarily, the endoscope here can be a bronchoscope, a pyeloscope, an esophagoscope, a gastroscope, an enteroscope, an otoscope, a rhinoscope, a stomatoscope, a laryngoscope, a colposcope, a laparoscope, an arthroscope, etc., and the embodiment of the present application does not specifically limit the type of the endoscope.

[0030] The side wall of the passive bending section 110 is provided with a through hole 111, where the through hole 111 penetrates from the outer circumference of the passive bending section 110 to the inner circumference of the passive bending section 110, and the through hole 111 extends along the extension direction of the passive bending section 110, and the maximum depth of the through hole 111 is less than half of the outer diameter of the passive bending section 110, and the blocking structure 200 is connected to the sheath tube 100 and seals the through hole 111. Specifically, the blocking structure 200 covers and seals the through hole 111, thereby preventing the material to be sucked between the active bending section 310 and the sheath tube 100 from leaking from the through hole 111 to the outside of the sheath tube 100.

[0031] The passive bending section 110 includes an expandable portion 112 arranged opposite to the through opening 111 in the radial direction. Figure 1 Taking the perspective shown in FIG. 1 as an example, the above-mentioned expandable portion 112 can be formed after the through hole 111 is opened on the passive bending section 110. The expandable portion 112 is located below the through hole 111. When the passive bending section 110 is bent and the side of the expandable portion 112 away from the through hole 111 is the stretching side, the expandable portion 112 expands outward in a direction perpendicular to the plane where the bending direction of the passive bending section 110 is located. Specifically, the bending direction of the passive bending section 110 is Figure 2 The direction indicated by the y arrow line is perpendicular to the plane where the y arrow line is located, that is, the direction indicated by the x arrow line. Figure 2 The direction indicated by the x-arrow line expands radially outward.

[0032] It should be noted that when the passive bending section 110 is bent, one side of the passive bending section 110 is a stretching side and the other side is an extrusion side. Figure 2 Taking the perspective shown as an example, the lower side of the passive bending section 110 is the stretching side.

[0033] In the present application, a through hole 111 is provided on the passive bending section 110, and the through hole 111 will destroy the continuity of the passive bending section 110, resulting in stress concentration near the through hole 111 when the passive bending section 110 is bent, and the stress concentration area will be more easily deformed due to excessive local stress, so that the expandable portion 112 opposite to the through hole 111 in the radial direction expands outward in a direction perpendicular to the plane where the bending direction of the passive bending section 110 is located, so as to release the stress accumulated when the passive bending section 110 is bent. After the expandable portion 112 expands radially outward, the distance between the inner wall of the expandable portion 112 and the active bending section 310 will be increased, thereby increasing the flow area at that place and increasing the minimum value of each maximum distance, so that the target object (the stone stuck in the related art) can smoothly pass through the gap between the bent active bending section 310 and the bent passive bending section 110, thereby solving the problem of unsmooth discharge of stones waiting for suction.

[0034] After the expandable portion 112 is radially expanded, the flow path of the target object is as follows: Fig. 9 Taking the position shown in the middle a view as an example, the target first passes over the active bending section 310, and when the target flows to the narrow area ( Fig. 9 The target flows circumferentially to the side of the active bending section 310, thereby entering the expanded expandable portion 112, and then the target flows circumferentially again to the bottom of the active bending section 310 ( Fig. 9 e perspective in order to pass through narrow areas.

[0035] In addition, when the passive bending section 110 of the present application does not follow the active bending section 310 to bend, the portion of the blocking structure 200 located at the through-opening 111 will not be squeezed, and thus the blocking structure 200 will not bulge toward the outside of the through-opening 111. That is to say, when the passive bending section 110 is in a straight state, the outer diameters of various portions of the passive bending section 110 in its own extension direction are relatively small, which facilitates the insertion of the sheath 100 into the human body.

[0036] The operation methods of using the negative pressure suction sheath of the present application to solve the problem of unsmooth discharge of stones while waiting for the suctioned material include the following two methods:

[0037] 1. After the insertion portion 300 of the endoscope is inserted into the sheath tube 100 and the active bending section 310 drives the sheath tube 100 to bend, the expanded expandable portion 112 corresponds to the minimum value of each maximum distance of the sheath tube 100 in the prior art, that is, after the active bending section 310 is inserted into the sheath tube 100 and drives the sheath tube 100 to bend, the minimum value of each maximum distance is greater than the size of the target object, so that the target object can smoothly pass through the gap between the bent active bending section 310 and the inner wall of the tube section of the sheath tube 100 bent by the active bending section 310, thereby solving the problem of unsmooth discharge of stones while waiting for suction.

[0038] 2. After the insertion portion 300 of the endoscope is inserted into the sheath 100 and the active bending section 310 drives the sheath 100 to bend, the raised expandable portion 112 does not correspond to the minimum value of each maximum distance of the sheath 100 in the prior art. For example, the expanded expandable portion 112 is located proximal to the minimum value of each maximum distance of the sheath 100. At this time, it is only necessary to pull the active bending section 310 to move the active bending section 310 proximally until a part of the bent active bending section 310 enters the raised expandable portion 112, so that the minimum value of each maximum distance is larger than the size of the target object by utilizing the raised expandable portion 112, thereby introducing the target object stuck between the bent sheath 100 and the bent active bending section 310 into the raised expandable portion 112, so as to solve the problem of the target object being stuck between the bent sheath 100 and the bent active bending section 310.

[0039] See also Figures 3 to 5 In an optional embodiment, the depth of the middle portion of the through opening 111 along the extension direction of the passive bending section 110 is less than the depth of other portions of the through opening 111 .

[0040] In this embodiment, the expandable portion 112 is naturally formed after the through-hole 111 is opened, so the height dimension of the expandable portion 112 is related to the depth of the through-hole 111, and the sum of the two is equal to the outer diameter of the through-hole 111. In this embodiment, the depth of the middle part of the through-hole 111 is shallow, so the height of the middle part of the expandable portion 112 can be larger, and the larger the height of the middle part of the expandable portion 112, the larger the radial expansion dimension of the expandable portion 112 along the direction indicated by the x-arrow line. Therefore, after adopting the structure of this embodiment, the distance between the inner wall of the expandable portion 112 and the active bending section 310 can be further increased, so that larger stones waiting to be sucked can pass through the gap between the expandable portion 112 and the active bending section 310, so as to improve the passability of the sheath tube 100. In addition, since the depth of the through-hole 111 on both sides along its own extension direction is large, the height of the two sides of the expandable portion 112 is also small, which obviously makes the expandable portion 112 have a relatively low structural strength, so that the expandable portion 112 is more easily deformed.

[0041] See also Figure 4 In an optional embodiment, the bottom wall of the through opening 111 includes an arc-shaped portion 1111 , and the arc-shaped portion 1111 is located in the middle of the through opening 111 along the extension direction of the passive bending section 110 .

[0042] In this embodiment, the arcuate portion 1111 protrudes in the direction away from the expandable portion 112, and the bottom wall of the through-port 111 forms the arcuate portion 1111, which is located in the middle of the through-port 111. The arcuate portion 1111 itself is characterized by being high in the middle and low on both sides, that is, the middle depth of the middle of the through-port 111 is small, and the depths of both sides of the middle are large, which can further increase the height of the middle of the expandable portion 112, thereby further improving the passability of the sheath tube 100. At the same time, the depths of both sides of the middle of the through-port 111 are large, which can make the heights of both sides of the expandable portion 112 smaller, thereby making it easier for the expandable portion 112 to deform.

[0043] Please continue reading Figure 4 In an optional embodiment, the bottom wall of the through hole 111 further includes two connecting parts 1112, which are respectively located on both sides of the arc-shaped part 1111 and are both connected to the arc-shaped part 1111, and each connecting part 1112 is a plane. In this embodiment, the connecting part 1112 is a plane. Compared with a curved surface, the height of the plane is consistent. Therefore, the connecting part 1112 is a plane, which can make the two sides of the through hole 111 have a greater depth, and the depth will not decrease in the extension direction of the through hole 111, so that the passive bending section 110 is more conducive to bending.

[0044] See also Figure 1 and Figure 2 In some other optional embodiments, the depth of the through opening 111 may also remain unchanged along the extension direction of the passive bending section 110 .

[0045] In order to prevent the blocking structure 200 from deforming inwards during the bending of the passive bending section 110, please refer to Figures 6 to 8 In an optional embodiment, the inner wall of the through opening 111 has a profile of a supporting tongue 113 formed on the side wall of the passive bending section 110 , and the supporting tongue 113 is located at one end of the through opening 111 .

[0046] In this embodiment, a support tongue 113 is also formed on the passive bending section 110 while a through opening 111 is formed. When the passive bending section 110 bends, the two sides of the through opening 111 will approach each other, so the support tongue 113 will also approach the other end of the through opening 111. In this way, the support tongue 113 can provide support for a portion of the blocking structure 200 to prevent the blocking structure 200 from collapsing into the interior of the passive bending section 110, thereby increasing the distance between the blocking structure 200 and the active bending section 310, preventing stones waiting to be sucked from being stuck between the active bending section 310 and the blocking structure 200, thereby further improving the passability of the sheath 100.

[0047] See also Figure 6 In an optional embodiment, the direction in which one end of the supporting tongue portion 113 connected to the other portion of the passive bending section 110 extends toward the other end is the first direction ( Figure 6 The first direction is parallel to the extension direction of the passive bending section 110, so that the support performance of the supporting tongue 113 on the blocking structure 200 can be further improved, so as to further improve the passability of the sheath tube 100. Of course, the first direction can also be parallel to the extension direction of the passive bending section 110. Figure 2 Parallel to the direction shown by the x-arrow line.

[0048] Please continue reading Figure 6 In an optional embodiment, a first section 101 and a second section 102 are formed on the side wall of the passive bending section 110, the first section 101 and the second section 102 intersect, and the inner wall of the through-hole 111 includes the first section 101 and the second section 102; the first section 101 and the second section 102 are both inclined relative to the axial direction of the passive bending section 110, the angle between the first section 101 and the second section 102 is an acute angle, and the inclination directions of the first section 101 and the second section 102 are opposite, and the plane where the inner wall of the supporting tongue 113 is located coincides with the second section 102.

[0049] In this embodiment, the inclination directions of the first section 101 and the second section 102 are opposite, and the angle between the two is an acute angle, that is, the groove depth of the through-opening 111 at the intersection between the first section 101 and the second section 102 is the largest. Therefore, when the passive bending section 110 bends, the passive bending section 110 will bend at this point. In other words, the bending point of the passive bending section 110 is adjacent to the supporting tongue 113, and the portion of the blocking structure 200 located at the bending point has the largest degree of collapse. Therefore, the supporting tongue 113 can support the portion of the blocking structure 200 with the largest degree of collapse, which can further improve the passability of the sheath 100.

[0050] In an optional embodiment, the number of the through openings 111 includes two, the two through openings 111 are respectively arranged on opposite sides of the passive bending section 110 , and the two through openings 111 are spaced apart along the extension direction of the passive bending section 110 .

[0051] Generally speaking, the active bending section 310 of the endoscope has a bidirectional bending function. If only one through-hole 111 is provided, and when the passive bending section 110 bends following the active bending section 310, if the through-hole 111 is located just on the extrusion side of the passive bending section 110, the expandable portion 112 will not expand radially outward. In order to enable the negative pressure suction sheath of the present application to adapt to the bidirectional bending of the active bending section 310, the present embodiment provides through-holes 111 on opposite sides of the passive bending section 110, and the sealing structure 200 seals each through-hole 111. In this way, no matter which direction the active bending section 310 bends in, there is always a through-hole 111 located on the stretching side of the passive bending section 110, thereby causing the corresponding expandable portion 112 to expand radially outward. It can be seen that after adopting the structure of this embodiment, no matter in which direction the active bending section 310 bends, the expandable portion 112 will expand radially outward. In other words, no matter in which direction the active bending section 310 bends, when the negative pressure suction sheath is used to aspirate the stones, the stones will not be stuck between the active bending section 310 and the passive bending section 110.

[0052] In an optional embodiment, when the passive bending section 110 bends and squeezes the portion of the sealing structure 200 that seals the through-opening 111 , the squeezed portion of the sealing structure 200 bulges toward the outside of the through-opening 111 .

[0053] When the negative pressure suction sheath of the present application is used, the insertion portion 300 of the endoscope can be inserted into the sheath tube 100. When the active bending section 310 drives the passive bending section 110 to bend, the passive bending section 110 will squeeze the portion of the blocking structure 200 that blocks the through-opening 111, so that the two ends of this portion of the blocking structure 200 are close to each other, thereby causing this portion of the blocking structure 200 to bulge toward the outside of the through-opening 111, which can increase the cross-sectional area of ​​the passive bending section 110 at its own through-opening 111, thereby increasing the flow area there and increasing the minimum value of each maximum distance, so that the target object can smoothly pass through the gap between the curved active bending section 310 and the curved passive bending section 110, thereby solving the problem of unsmooth discharge of stones while waiting for suction.

[0054] It should be noted that the state of the blocking structure 200 bulging toward the outside of the through-opening 111 is not shown in the figure. Here, the direction in which the squeezed portion of the blocking structure 200 bulges is explained. This portion of the blocking structure 200 bulges in the direction away from the through-opening 111 ( Figure 2It bulges radially outward (in the direction indicated by the arrow line z).

[0055] In an optional embodiment, the blocking structure 200 includes a blocking film and a braided layer (not shown in the figure), the blocking film is connected to the braided layer, and when the passive bending section 110 bends and squeezes the portion of the blocking structure 200 that seals the through-hole 111, the squeezed portion of the braided layer bulges toward the outside of the through-hole 111. Further, the blocking structure 200 is an annular structural member.

[0056] In an optional embodiment, when the passive bending section 110 is in a straight state, the portion of the sealing structure 200 that seals the through-opening 111 pre-bulges toward the outside of the through-opening 111; when the passive bending section 110 bends and squeezes the pre-bulged portion of the sealing structure 200, the pre-bulged portion of the sealing structure 200 bulges toward the outside of the through-opening 111.

[0057] In this embodiment, the blocking structure 200 is initially pre-bulged outward, that is, the blocking structure 200 has a certain tendency to expand outward when not subjected to external force, which makes the outer side of the blocking structure 200 have a higher initial curvature. In this way, when the blocking structure 200 is subjected to extrusion force, the pre-bulged structure can better adapt to the bending deformation of the passive bending section 110, thereby making it easier for the blocking structure 200 to expand and bulge outward.

[0058] 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 enlightenment of the present application, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present application and the claims, all of which are within the protection of the present application.

Claims

1. A negative pressure suction sheath, characterized in that: The invention comprises a sheath tube (100) and a blocking structure (200), wherein the sheath tube (100) is arranged at the distal end of the negative pressure suction sheath, the distal end of the sheath tube (100) has a passive bending section (110) capable of bending following the active bending section (310) of the endoscope, the side wall of the passive bending section (110) is provided with a through opening (111), the through opening (111) extends along the extension direction of the passive bending section (110), the maximum depth of the through opening (111) is less than half of the outer diameter of the passive bending section (110), and the blocking structure (200) is connected to the sheath tube (100) and seals the through opening (111); The passive bending section (110) comprises an expandable portion (112) arranged radially opposite to the through opening (111); when the passive bending section (110) is bent and the side of the expandable portion (112) facing away from the through opening (111) is a stretching side, the expandable portion (112) expands outwardly in a direction perpendicular to a plane where the bending direction of the passive bending section (110) is located; The depth of the middle portion of the through opening (111) along the extension direction of the passive bending section (110) is smaller than the depth of other portions of the through opening (111).

2. The negative pressure suction sheath according to claim 1, characterized in that: The bottom wall of the through opening (111) comprises an arc-shaped portion (1111), and the arc-shaped portion (1111) is located in the middle of the through opening (111) in the extension direction of the passive bending section (110).

3. The negative pressure suction sheath according to claim 2, characterized in that: The bottom wall of the through opening (111) further comprises two connecting portions (1112), the two connecting portions (1112) being respectively located on both sides of the arc-shaped portion (1111) and both being connected to the arc-shaped portion (1111), and each connecting portion (1112) being a plane.

4. The negative pressure suction sheath according to claim 1, characterized in that: The inner wall of the through opening (111) has a profile forming a supporting tongue (113) on the side wall of the passive bending section (110), and the supporting tongue (113) is located at one end of the through opening (111).

5. The negative pressure suction sheath according to claim 4, characterized in that: The direction in which one end of the supporting tongue (113) connected to the other part of the passive bending section (110) extends toward the other end is a first direction, and the first direction is parallel to the extension direction of the passive bending section (110).

6. The negative pressure suction sheath according to claim 5, characterized in that: A first cut surface (101) and a second cut surface (102) are formed on the side wall of the passive bending section (110), the first cut surface (101) and the second cut surface (102) intersect, and the inner wall of the through opening (111) includes the first cut surface (101) and the second cut surface (102); The first section (101) and the second section (102) are both arranged to be inclined relative to the axial direction of the passive bending section (110); the angle between the first section (101) and the second section (102) is an acute angle; the first section (101) and the second section (102) are inclined in opposite directions; and the plane where the inner wall of the supporting tongue (113) is located coincides with the second section (102).

7. The negative pressure suction sheath according to claim 1, characterized in that: The number of the through openings (111) includes two, the two through openings (111) are respectively arranged on opposite sides of the passive bending section (110), and the two through openings (111) are spaced apart along the extension direction of the passive bending section (110).

8. The negative pressure suction sheath according to claim 1, characterized in that: When the passive bending section (110) bends and squeezes the portion of the sealing structure (200) that seals the through-opening (111), the squeezed portion of the sealing structure (200) bulges toward the outside of the through-opening (111).

9. The negative pressure suction sheath according to claim 8, characterized in that: When the passive bending section (110) is in a straightened state, the portion of the blocking structure (200) that seals the through-opening (111) pre-bulges toward the outside of the through-opening (111); When the passive bending section (110) bends and presses the pre-bulged portion of the blocking structure (200), the pre-bulged portion of the blocking structure (200) bulges toward the outside of the through opening (111).

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