Bipolar electrosurgical snare and operating method thereof

Abstract

A bipolar electrosurgical snare and an operating method thereof. The bipolar electrosurgical snare comprises a sheath and a snare loop, the snare loop having a deployed position and a retracted position, the snare loop comprising a first electrode wire, a second electrode wire, and an insulating member, and a cutting space is formed between the first electrode wire and the second electrode wire.

Description

Bipolar electric coil device and its operation method

[0001] Related applications

[0002] This application claims priority to Chinese patent applications filed on March 25, 2025, with application number 202510362142.0, entitled "Bipolar Electric Snag and its Operating Method", and on April 29, 2025, with application number 202510559009.4, entitled "Bipolar Electric Snag", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of endoscopy technology, and in particular to a bipolar electric snare and its operating method. Background Technology

[0004] Polyps may grow in the pores and cavities of organisms. To remove polyps, a monopolar electric snare can be used, which includes an electrode patch that is attached to the outside of the organism and a snare. After the snare is placed over the polyp, an electric current is applied, and the snare can cut the polyp.

[0005] Electrode patches are cumbersome to apply and use, and high-frequency current flows through a large number of tissue structures within the body. Therefore, bipolar electric snares have been developed. The snare of a bipolar electric snare consists of two insulated coils that are joined together and cut directly by the bipolar electric snare itself under the action of high-frequency current.

[0006] However, the effectiveness of bipolar electric snares still needs to be improved. Summary of the Invention

[0007] According to various embodiments of this application, a bipolar electric coil device and a method of operating the same are provided.

[0008] This application provides a bipolar electric snare, comprising: a sheath having a conduit; and a snare disposed on the sheath and capable of sliding along the conduit. The snare has an extended position and a retracted position. The snare includes a first electrode wire, a second electrode wire, and an insulating member. The distal ends of the first electrode wire and the second electrode wire are connected to the insulating member. A cutting space is formed between the first electrode wire and the second electrode wire. A first working section of the first electrode wire is used to contact the tissue to be cut, and a second working section of the second electrode wire is used to contact the tissue to be cut. The contact area of ​​the first working section is smaller than the contact area of ​​the second working section.

[0009] This application provides a bipolar electric snare, comprising: a sheath having a conduit; and a snare disposed on the sheath and capable of sliding along the conduit. The snare has an extended position and a retracted position. The snare includes a first electrode wire, a second electrode wire, and an insulating member. The distal ends of the first electrode wire and the second electrode wire are connected to the insulating member, and a cutting space is formed between the first electrode wire and the second electrode wire. A first working section of the first electrode wire is used to contact the tissue to be cut, and a second working section of the second electrode wire is used to contact the tissue to be cut. An insulating portion is provided on the sheath, and the first working section and the second working section are separated by the insulating portion during the process of the snare retracting into the sheath.

[0010] This application provides a bipolar electric snare, comprising: a sheath having a conduit; and a snare disposed on the sheath and capable of sliding along the conduit, the snare having an extended position and a retracted position, the snare comprising: an insulating element; a first electrode wire distally connected to the insulating element, a first working section of the first electrode wire for contacting the tissue to be cut; and a second electrode wire distally connected to the insulating element, a second working section of the second electrode wire for contacting the tissue to be cut, a cutting space being formed between the second electrode wire and the first electrode wire; wherein at least one of the first and second working sections comprises an internal structure and an external structure, the external structure at least covering a portion of the surface of the internal structure, and the melting point of the material of the external structure being higher than or equal to the melting point of the material of the internal structure.

[0011] This application provides a method for operating a bipolar electric snare, wherein the bipolar electric snare is the aforementioned bipolar electric snare. The method includes: extending the snare from a sheath to an unfolded position; placing the snare around the root of the tissue to be cut; adjusting the snare from the unfolded position to a retracted position, wherein a first working section and a second working section contact the tissue to be cut; and during the adjustment process, applying a high-frequency working voltage to the first electrode wire and the second electrode wire to cause the first working section to cut the tissue to be cut.

[0012] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0013] To better describe and illustrate embodiments and / or examples of the inventions disclosed herein, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed inventions, the currently described embodiments and / or examples, or the best mode of these inventions as currently understood.

[0014] Figure 1 is a schematic structural diagram of a bipolar electric snare according to one or more embodiments;

[0015] Figure 2 is a schematic diagram of the structure of a bipolar electric coil according to one or more embodiments;

[0016] Figure 3 is a schematic cross-sectional view of a bipolar electric snare according to one or more embodiments;

[0017] Figure 4 is a schematic diagram of the structure of a snare according to one or more embodiments;

[0018] Figure 5 is a schematic diagram of the structure at section AA in Figure 4;

[0019] Figure 6 is a structural schematic diagram of an insulating member according to one or more embodiments;

[0020] Figure 7 is a schematic structural diagram of an insulating member with a flat structure according to one or more embodiments;

[0021] Figure 8 is a schematic cross-sectional view of an insulating member according to one or more embodiments;

[0022] Figure 9 is a schematic diagram of the structure of the connecting tube in a bipolar electric coil according to one or more embodiments;

[0023] Figure 10 is a schematic diagram of the structure of the connecting tube in another bipolar electric coil according to one or more embodiments;

[0024] Figure 11 is a schematic diagram of the rotating fit between the multi-cavity tube segment and the sheath in a bipolar electric snare according to one or more embodiments;

[0025] Figure 12 is an exploded view of the multi-lumen tube segment, sheath, distal limiting part, and proximal limiting part in Figure 11;

[0026] Figure 13 is a schematic diagram of another structure for the rotational engagement of the multi-cavity tube segment and sheath in a bipolar electric snare according to one or more embodiments;

[0027] Figure 14 is an enlarged structural diagram of part A in Figure 13;

[0028] Figure 15 is a structural schematic diagram of the first rotating connector in a bipolar electric coil according to one or more embodiments;

[0029] Figure 16 is a structural schematic diagram of the second rotating connector in a bipolar electric coil according to one or more embodiments;

[0030] Figure 17 is a schematic cross-sectional view of the first electrode wire in a bipolar electric coil according to one or more embodiments;

[0031] Figure 18 is a schematic cross-sectional view of the second electrode wire in a bipolar electric coil according to one or more embodiments;

[0032] Figure 19 is a cross-sectional schematic diagram of a snare according to one or more embodiments;

[0033] Figure 20 is a cross-sectional schematic diagram of another loop according to one or more embodiments;

[0034] Figure 21 is a schematic assembly structure diagram of the rotating connection structure according to one or more embodiments;

[0035] Figure 22 is a schematic exploded view of a rotating connection structure according to one or more embodiments;

[0036] Figure 23 is a schematic diagram of the structure of the operating mechanism according to one or more embodiments;

[0037] Figure 24 is a schematic structural diagram of an operating mechanism according to one or more embodiments;

[0038] Figure 25 is a schematic diagram of the structure of the second operating part in a bipolar electric snare according to one or more embodiments;

[0039] Figure 26 is a cross-sectional schematic diagram of the second operating part in a bipolar electric snare according to one or more embodiments;

[0040] Figure 27 is a schematic diagram of the pin structure in a bipolar electric coil according to one or more embodiments;

[0041] Figure 28 is a schematic top view of a second operating unit according to one or more embodiments;

[0042] Figure 29 is a schematic diagram of the pin structure in another bipolar coil according to one or more embodiments;

[0043] Figure 30 is a schematic structural block diagram of an endoscope system according to one or more embodiments;

[0044] Figure 31 is a schematic flowchart of a method for operating a bipolar electric snare according to one or more embodiments;

[0045] Figure 32 is a structural schematic diagram of a bipolar electric coil in a first state according to one or more embodiments;

[0046] Figure 33 is a schematic diagram of the working principle of a bipolar electric snare in a first state according to one or more embodiments;

[0047] Figure 34 is a structural schematic diagram of a bipolar electric coil device in a second state according to one or more embodiments;

[0048] Figure 35 is a schematic diagram of the working principle of a bipolar electric snare according to one or more embodiments;

[0049] Figure 36 is a schematic diagram of the working principle of another bipolar electric snare according to one or more embodiments;

[0050] Figure 37 is a schematic diagram of the working principle of another bipolar electric snare according to one or more embodiments;

[0051] Figure 38 is a schematic diagram of the working principle of another bipolar electric snare according to one or more embodiments;

[0052] Figure 39 is a structural schematic diagram of a bipolar electric coil in a third state according to one or more embodiments;

[0053] Figure 40 is a structural schematic diagram of a bipolar electric snare in a fourth state according to one or more embodiments;

[0054] Figure 41 is a schematic diagram of a bipolar electric snare used to cut tissue in an ex vivo experiment according to one or more embodiments.

[0055] Reference numerals: 1. First electrode wire; 101. First distal end; 102. First proximal end; 103. Inner ring surface; 11. First working section; 111. First internal structure; 112. First external structure; 12. Proximal extension section; 2. Second electrode wire; 201. Second distal end; 202. Second proximal end; 20. Second working section; 210. Second internal structure; 220. Second external structure; 21. First section; 22. Second section; 3. Insulating component; 31. Blade; 100. Sleeve; 110. First insulating layer; 120. Connecting tube; 130. Wire body; 131. First wire body; 132. Second wire body; 133. Third wire body; 140. Coating; 1001. Cutting space; 200. Sheath; 2010. Receiving space; 2011. Distal limiting part; 2012. Proximal limiting part;

[0056] 300. Operating mechanism; 310. First connecting tube; 320. Second connecting tube; 330. Insulating sleeve; 340. Second insulating layer; 4. First operating wire; 41. Third distal end; 5. Second operating wire; 51. Fourth distal end; 6. First operating part; 7. Second operating part; 70. Base; 71. Pin; 711. First contact; 712. Second contact; 7121. First limiting part; 7122. Second limiting part; 713. Insulating tube body; 7131. Conductive channel; 7132. Groove; 72. Seat body; 73. First ring structure; 74. Connecting piece;

[0057] 400. Rotating connection structure; 410. Fixing element; 420. Fixing block; 430. Sheath; 500. Insulating part; 501. First chamber; 502. Second chamber; 600. First rotating connector; 601. Internal thread structure; 610. Protrusion; 700. Second rotating connector; 701. Barbed structure; 710. Recess;

[0058] 1000, Bipolar electric snare; 1100, Cutting section; 1200, Flexible section; 1300, Connecting section; 1400, Operating section; 2000, Endoscope; 3000, Endoscopic system; 4000, Power supply. Detailed Implementation

[0059] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0060] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0061] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0062] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. For example, a first electrode wire may also be referred to as a second electrode wire, and a second electrode wire may also be referred to as a first electrode wire. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0063] In this application, unless otherwise expressly specified and limited, the terms "connected," "linked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a flexible connection or a rigid connection along at least one direction; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium, or a direct connection with an intermediate medium present; and they can also refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. The terms "installed," "set," "fixed," etc., can be broadly understood as connection. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0064] As used in this application, the terms "layer" and "region" refer to a material portion comprising a defined area and having a defined thickness. A layer can extend horizontally, vertically, and / or along a conical surface. A layer can be a region of uniform or non-uniform continuous structure, and its thickness perpendicular to the direction of extension may not exceed the thickness of the continuous structure. A layer can comprise multiple layers, which can be stacked layers or discretely extending layers. The shapes of the various regions and layers in the accompanying drawings, as well as their relative sizes and positional relationships, are merely illustrative and may deviate from actual dimensions due to manufacturing tolerances or technical limitations, and the design can be adjusted according to actual needs.

[0065] It should be noted that, in this application, the terms "distal end" and "proximal end" are used with the operator as the reference point. The end closer to the operator is called the proximal end or proximal portion, and the end farther from the operator is called the distal end or distal portion. The side facing the operator is called the proximal side or proximal side, and the side farther from the operator is called the distal side or distal side. Furthermore, "distal direction" and "proximal direction" represent two directions; the proximal-distal direction is parallel to both the distal and proximal directions, and does not specifically refer to forward or reverse directions. "Proximal end" and "distal end" can also refer to portions or ends of structures located in the corresponding directions.

[0066] Referring to FIG1, FIG1 illustrates a bipolar electric snare according to an embodiment of this application. In an exemplary embodiment, the bipolar electric snare 1000 can be used in an endoscopic environment or in an open environment. In one aspect, the bipolar electric snare 1000 may include an operating section 1400, a connecting section 1300, a flexible section 1200, and a cutting section 1100 arranged sequentially from proximal to distal. In another aspect, the bipolar electric snare 1000 may include multiple components whose functions can cooperate and whose layout can be staggered.

[0067] Referring to Figures 2 and 3, the bipolar electric coil 1000 may include a sheath 200, which may be primarily located in the flexible section 1200 and partially located in the connecting section 1300. The sheath 200 has a conduit extending from the proximal end to the distal end of the sheath 200. The sheath may be designed to be insulated, such as being made of PTFE material.

[0068] The bipolar electric snare 1000 may include a snare 100. The snare 100 is disposed within a sheath 200 and is slidable along the conduit. The axial direction L1 at the distal end of the sheath 200 may be substantially parallel to the X-axis direction. The snare 100 has an extended position and a retracted position. Figure 3 shows the snare 100 in the extended position, in which the snare 100 may extend substantially or completely out of the sheath 200. The snare 100 may be structurally flexible to retain the cutting space 1001 for accommodating the tissue to be cut. The snare 100 may also have other positions between the extended and retracted positions, for example, when the tissue to be cut is slightly small, the snare 100 needs to retract a distance relative to the extended position so that the snare 100 covers and contacts the tissue to be cut; this position may be referred to as the first position.

[0069] The snare 100 may include a first electrode wire 1 and a second electrode wire 2. The proximal end of the first electrode wire 1, i.e., the first proximal end 102, and the proximal end of the second electrode wire 2, i.e., the second proximal end 202, can be inserted into the sheath 200, and the two can be controlled separately or together.

[0070] Both the first electrode wire 1 and the second electrode wire 2 can be metal wires, capable of withstanding high-frequency voltage. Through pre-formed shapes, both the first electrode wire 1 and the second electrode wire 2 can maintain a certain shape and be elastically deformable. As shown in Figure 3, for example, the first electrode wire 1 and the second electrode wire 2 are similar to arc shapes in the XY plane, forming a cutting space 1001 between the first electrode wire 1 and the second electrode wire 2. Furthermore, it is assumed that the sheath 100 has a cutting surface along the XY plane and a perpendicular direction L2 to the cutting surface. Referring to Figure 2, the perpendicular direction L2 to the cutting surface is approximately along the Z-axis direction and can be perpendicular to the axial direction L1 at the distal end of the sheath 200.

[0071] The snare 100 may also include an insulating element 3. The distal end 101 of the first electrode wire 1 and the distal end 201 of the second electrode wire 2 are connected to the insulating element 3, and the first distal end 101 and the second distal end 201 are insulated from each other. Referring to Figures 32 and 33, the first working section 11 of the first electrode wire 1 is used to contact the tissue to be cut, and the second working section 20 of the second electrode wire 2 is used to contact the tissue to be cut. The contact area of ​​the first working section 11 is smaller than the contact area of ​​the second working section 20.

[0072] The contact area is the area in which the first working section 11 and the second working section 20 directly contact the tissue to be cut; Lg1 and Lg2 are the lengths of the first working section 11 and the second working section 20 in contact with the tissue, respectively.

[0073] For example, in Figure 35, the electrode wire of the loop 100 has a circular cross-section. The first working section 11 and the second working section 20 are in contact with the tissue at the vertex, that is, 1 / 2 of the outer circumference of the electrode wire is in contact with the tissue. Then, the contact area S1 of the first working section 11 is π*H1*Lg1 / 2, and the contact area S2 of the second working section 20 is π*H2*Lg2 / 2.

[0074] For example, in Figure 36, the electrode wire of the loop 100 has a square cross-section. The first working section 11 and the second working section 20 each have three cross-sections that come into contact with the tissue. Therefore, the contact area of ​​the first working section 11 is S1 = 3H1*Lg1, and the contact area of ​​the second working section 20 is S2 = 3H2*Lg2.

[0075] For example, in Figure 37, the electrode wire of the loop 100 has a circular cross-section, and 9 / 10 of the outer circumference of the electrode wire is in contact with the tissue. Then, the contact area S1 of the first working section 11 is S1 = 9π * H1 * Lg1 / 10, and the contact area S2 of the second working section 20 is S2 = 9π * H2 * Lg2 / 10.

[0076] For example, in Figure 38, the electrode wire of the loop 100 has a square cross-section. Three sections of the first working section 11 and the second working section 20 are in contact with the tissue, and 2 / 3 of the fourth section is in contact with the tissue. Then, the contact area S1 of the first working section 11 is S1 = 11H1*Lg1 / 3, and the contact area S2 of the second working section 20 is S2 = 11H2*Lg2 / 3.

[0077] The above examples illustrate only a few embodiments. Factors such as the cross-section, working length, and tissue coverage of the bipolar electric looper 1000 electrode wire all affect the contact area between the first working section of the first electrode wire, the second working section of the second electrode wire, and the tissue being cut. For example, when used to cut polyp tissue, the current density at the first working section 11 can be increased to improve cutting efficiency.

[0078] The bipolar electric snare 1000 is used to remove tissue, such as polyps, from a living organism. During cutting, a circuit is connected to the first electrode wire 1 and the second electrode wire 2, which then applies a high-frequency operating voltage to the snare 100. The first electrode wire 1 forms a circuit with the second electrode wire 2 through the tissue to be cut. The first electrode wire 1 and the second electrode wire 2 have different surface areas for contacting the tissue being cut, resulting in a high current density at the first working section 11, enabling efficient cutting. As cutting progresses, the snare 100 needs to be continuously retracted to maintain contact. The bipolar electric snare 1000 has high resection efficiency, helps avoid prolonged surgical time, and minimizes prolonged exposure of the human body to high-frequency current, thus avoiding adverse effects.

[0079] The snare 100 may also include a first insulating layer 110. The first insulating layer 110 extends from the proximal end of the first electrode wire 1 to the distal end and wraps around a portion of the first electrode wire 1, specifically, it may wrap around the proximal extension 12 of the first electrode wire 1. Referring to Figures 2 and 3, at least a portion of the first electrode wire 1 is exposed from the first insulating layer 110 to form a first working section 11, which is located in the distal region of the first electrode wire 1 and is positioned at least toward the cutting space 1001. The surface of the first electrode wire 1 covered by the first insulating layer 110 is not in contact with electrical conductivity, and the ratio of the contact area between the first electrode wire 1 and the polyp tissue to the contact area between the second electrode wire 2 and the polyp tissue is smaller, which can improve the cutting efficiency at the first electrode wire 1.

[0080] Based on the circumferential direction of the first electrode wire 1, the first working segment 11 is fully exposed to the first insulating layer 110. The distal end of the first insulating layer 110 can be relatively flush, making it easy to manufacture. The full exposure of the first working segment 11 allows for smooth cutting into the tissue.

[0081] The length of the first insulating layer 110 along the axial direction of the first electrode wire 1 can account for about three-quarters of the length of the first electrode wire 1, and the length of the proximal extension section 12 can be approximately three times that of the first working section 11. For example, the first insulating layer 110 can be an insulating coating or a heat-shrinkable insulating tube.

[0082] The second electrode wire 2 is exposed to form the second working section 20. Referring to Figure 3, the exposed length of the second working section 20 along its axial direction is greater than the exposed length of the first working section 11 along its axial direction. The contact area of ​​the first working section 11 is smaller than the contact area of ​​the second working section 20, ensuring the cutting efficiency at the first working section 11.

[0083] The second working segment 20 includes a first section 21 and a second section 22. The snare 100 has a position where the second section 22 is retracted into the sheath 200, and the first section 21 and the first working segment 11 are outside the sheath 200. The contact area of ​​the first section 21 is larger than the contact area of ​​the first working segment 11. As shown in Figure 3, the virtual line N between the proximal end of the first section 21 and the proximal end of the first working segment 11 is substantially parallel to the direction Y in Figure 2. That is, when the proximal extension segment 12 is retracted into the sheath 200 while the first working segment 11 is still outside the sheath 200, the first section 21 of the second working segment 20 is outside, and the second section 22 can be retracted into the sheath 200. At this time, the snare 100 can be said to be in the second position, as shown in Figure 39. The contact area between the first section 21 of the second electrode wire 2 and the tissue is larger than the contact area between the first working segment 11 and the tissue, ensuring the cutting efficiency at the first working segment 11. The first electrode wire 1 has an inner ring surface 103 in the distal region, which is exposed. In other embodiments, the outer surface of the first electrode wire 1 may be covered by the first insulating layer 110.

[0084] In some embodiments, based on the perpendicular direction L2 of the cutting surface of the loop 100, the first characteristic dimension of the cross-section of the first working segment 11 along the perpendicular direction L2 of the cutting surface is smaller than the second characteristic dimension of the cross-section of the second working segment 20 along the perpendicular direction L2 of the cutting surface. This helps to effectively configure the contact area, for example, by configuring the contact area through the thickness of the first working segment and the second working segment.

[0085] In some embodiments, based on the vertical direction L2 of the cutting surface of the loop 100, the first characteristic dimension of the cross section of the first working segment 11 along the vertical direction L2 of the cutting surface is smaller than the second characteristic dimension of the cross section of the first section 21 in the second working segment 20 along the vertical direction L2 of the cutting surface.

[0086] When the snare 100 is in the second position, based on the perpendicular direction L2 of the cutting surface, the first characteristic dimension of the first working segment 11 is smaller than the second characteristic dimension of the first section 21. The first section 21 and the second section 22 may have cross-sections of the same shape and size. In other embodiments, the first section 21 and the second section 22 may have cross-sections of different but identical shapes and sizes. In other embodiments, the characteristic dimension of the first section 21 is referred to as the third characteristic dimension, and furthermore, the third characteristic dimension is larger than the fourth characteristic dimension of the second section 22, ensuring cutting efficiency during the retraction process of the snare 100.

[0087] Referring to Figure 35, in some embodiments, the cross-sectional shape of both the first working segment 11 and the second working segment 20 is circular. The diameter of the first working segment 11 is smaller than the diameter of the second working segment 20, resulting in better structural strength and easier dimensional control for the first electrode wire 1 and the second electrode wire 2. Referring to Figures 35, 2, and 3, the first electrode wire 1 and the second electrode wire 2 can be at the same height along the Z-axis, and the shortest path between them can be used as the cutting surface Q. Subsequently, along the perpendicular direction L2 of the cutting surface, the first working segment 11 of the first electrode wire 1 has a first characteristic dimension H1, and the second working segment 20 of the second electrode wire 2 has a second characteristic dimension H2. The circle can be a perfect circle or a near-circular shape.

[0088] Optionally, both the cross-sectional shape of the first working segment 11 and the cross-sectional shape of the second working segment 20 can be flat; or, one can be flat and the other circular, for example, the cross-sectional shape of the first working segment 11 is flat and the cross-sectional shape of the second working segment 20 is circular. This flat shape has a major axis and a minor axis, the major axis being along the cutting surface Q, and the minor axis being along the direction perpendicular to the cutting surface L2 of the loop 100. The first characteristic dimension H1 of the first working segment 11 along the direction perpendicular to the cutting surface is smaller than the second characteristic dimension H2 of the second working segment 20 along the direction perpendicular to the cutting surface, which helps to effectively configure the contact area.

[0089] Optionally, the cross-sectional shape of the first working segment 11 and / or the cross-sectional shape of the second working segment 20 can be polygonal or the like.

[0090] Optionally, the surfaces of the first working section 11 and the second working section 20 can also be spiral-shaped, and their cross-sections are approximately circular.

[0091] For example, the ratio of the first feature dimension to the second feature dimension is less than 0.90, for example, 0.89. This ensures a smaller contact area for the first working segment 11, achieving efficient cutting. Optionally, the ratio of the first feature dimension to the second feature dimension can be in the range of 0.5 to 0.9, for example, 0.55 to 0.90, which can better ensure the durability of the first working segment 11.

[0092] The ratio of the first feature dimension to the second feature dimension can be less than or equal to 0.75, for example, 0.7 or 0.6, and the ratio can be 0.5. When the snare 100 retracts into the sheath 200, and the first working segment 11 and the second working segment 20 extend from the sheath 200, the difference in contact area between the two working segments remains relatively large, enabling efficient cutting. Specifically, the feature dimension ratio of the first working segment 11 to the first section 21 can be less than 0.75. For cutting small tissues, this ratio can also be less than 0.5.

[0093] The cross-sectional shape of the first working section 11 can be circular or substantially circular, and the wire diameter of the first working section 11 is greater than or equal to 0.25 mm, ensuring the first electrode wire 1 has sufficient strength. The cross-sectional shape of the second working section 20 can be circular, and the wire diameter of the second working section 20 is less than or equal to 0.45 mm. The bipolar electric coil 1000 is small in size and can adapt to the endoscopic working environment. The wire diameter of the second working section 20 can range from 0.35 mm to 0.45 mm; the wire diameter of the first working section 11 can range from 0.25 mm to 0.35 mm. For example, the wire diameter of the first working section 11 is 0.28 mm, and the wire diameter of the second working section 20 is 0.4 mm.

[0094] Referring to Figures 3 and 4, the insulating member 3 includes a cutting edge 31. The cutting edge 31 is located between the first working section 11 and the second working section 20, and is used to form a cutting space 1001, potentially forming a portion of the cutting space 1001. Specifically, the cutting edge of the cutting edge 31 is positioned along the XY plane, continuing between the first working section 11 and the second working section 20. When the first working section 11 is substantially retracted into the sheath 200, the distance between the first working section 11 and the second working section 20 is difficult to reduce further; at this point, the snare 100 can be considered to be in a third position. The tissue to be cut often still has a connecting portion at this point. During the final stage of resection, the cutting edge 31 can be used to completely remove the polyp tissue, ensuring the surgical outcome.

[0095] Referring to Figure 5, the overall size of the insulating component 3 is relatively small, and the cutting edge of the blade 31 can be blunt. The material of the insulating component 3 can be, for example, ceramic. Along the Z-axis, the cutting edge is basically aligned with the central axis of the first working section 11; along the X-axis, the cutting edge is basically located at the inner side of the first working section 11.

[0096] When the snare 100 is in the retracted position, at least part of the insulating element 3 is located within the conduit of the sheath 200. For example, the cutting edge and even the cutting portion 31 are located within the conduit. This ensures that the tissue to be cut is severed. For example, the insulating element 3 is entirely located within the conduit of the sheath 200.

[0097] In some embodiments, the insulating member 3 includes a tapered portion located at the distal end that decreases in size toward the distal end; optionally, the tapered portion has an arcuate surface.

[0098] Referring to Figures 4, 5, and 7, the dimension of the insulating member 3 along the Z-axis is smaller than its dimension along the Y-axis. For example, the cross-section of the insulating member 3 based on the YZ plane has a flattened structure, improving the adhesion of the snare 100 to the wall, allowing the electrode wire and cutting edge to be closer to the root of the object being cut along the Z-axis, resulting in a more thorough cut. The dimension J below the cutting edge 31 of the insulating member 3 can range from 0.35 mm to 0.55 mm; for example, the dimension J ranges from 0.25 mm to 0.45 mm, which can be smaller than the second feature dimension of the second working section 20.

[0099] Referring to Figures 4 and 6, the distal ends of the first electrode wire 1 and the second electrode wire 2 can be fixed with protrusions respectively. The first electrode wire 1 and the second electrode wire 2 are respectively passed through the insulating member 3 and limited by their respective protrusions. The first electrode wire 1 and the second electrode wire 2 are close to the blade 31, for example, they can be close to each other.

[0100] Referring to Figures 7 and 8, a countersunk hole is provided at the distal end of the insulating component 3, which is then connected to the first electrode wire 1 and the second electrode wire 2 via adhesive injection. In some other embodiments, the first electrode wire 1 and the second electrode wire 2 are fused into a ball and then connected to the insulating component 3.

[0101] Referring to Figure 9 and in conjunction with Figures 2 and 3, the snare 100 may further include a connecting tube 120. The connecting tube 120 is fixed to the proximal ends of the first electrode wire 1 and the second electrode wire 2, thereby enabling synchronous control of the first electrode wire 1 and the second electrode wire 2. Exemplarily, the connecting tube 120 is a double-hole heat-shrinkable insulating tube to insulate the first electrode wire 1 and the second electrode wire 2. The connecting tube 120 is disposed within the sheath tube 200, allowing it to slide along the tube and rotate about its axis. The connecting tube 120 constrains the proximal ends of the first electrode wire 1 and the second electrode wire 2 to be arranged side-by-side; correspondingly, the insulating member 3 constrains the distal ends of the first electrode wire 1 and the distal ends of the second electrode wire 2 to be arranged side-by-side. The first electrode wire 1 and the second electrode wire 2 are constrained, preventing entanglement and knotting under their own elasticity, ensuring the shape of the cutting space 1001, and allowing adjustment of the spatial angle of the snare 100 to facilitate placement on polyps at different locations for cutting. Furthermore, the first electrode wire 1 and the second electrode wire 2 are aligned, resulting in a clean cut.

[0102] The bipolar electric snare 1000 also includes control wires. Specifically, the control wires may include a first control wire 4 and a second control wire 5, which can be used to form the control mechanism 300 of the bipolar electric snare 1000. The distal end, i.e., the third distal end 41, of the first control wire 4 is fixed to the proximal end of the first electrode wire 1. The first control wire 4 is electrically connected to the first electrode wire 1. The first control wire 4 can be soldered to the first electrode wire 1. The first control wire 4 can be fixed to the first electrode wire 1 through a first connecting tube 310, which, exemplarily, can be a metal tube. Similarly, the distal end, i.e., the fourth distal end 51, of the second control wire 5 is fixed to the proximal end of the second electrode wire 2, and the second control wire 5 is electrically connected to the second electrode wire 2. For example, the second control wire 5 is connected to the second electrode wire 2 through a second connecting tube 320, which can be a metal tube; for example, the second control wire 5 can be soldered to the second electrode wire 2. Both the first control wire 4 and the second control wire 5 are inserted into the sheath tube 200 to control the loop 100 on the proximal side of the sheath tube 200.

[0103] The bipolar electric coil 1000 may include a second insulating layer 340. The second insulating layer 340 wraps around a first operating wire 4, or around a second operating wire 5, or both the first operating wire 4 and the second operating wire 5, to insulate the first operating wire 4 from the second operating wire 5. This allows the coil 100 to be pushed and pulled along the conduit to different positions and shapes, and also allows for effective rotation of the coil 100 to different rotation angles. In other embodiments, the sheath 200 includes two mutually insulated conduits for respectively accommodating the first operating wire 4 and the second operating wire 5.

[0104] Referring to Figure 10, the bipolar electric coil 1000 may include an insulating sleeve 330, which is fitted onto the first connecting tube 310 or the second connecting tube 320 to prevent short circuits between the first electrode wire 1 and the second electrode wire 2, ensuring normal circuit operation. The second insulating layer 340 may be a heat-shrinkable textured tube or an insulating coating, and the insulating sleeve 330 may also be a heat-shrinkable tube or an insulating coating. In some embodiments, the first insulating layer 110 and the second insulating layer 340 may be connected.

[0105] In some embodiments, the second insulating layer 340 and the insulating sleeve 330 may be integrally formed.

[0106] In some embodiments, the connecting tube 120 is sleeved over the first connecting tube 310, the second connecting tube 320 and the insulating sleeve 330.

[0107] In some embodiments, the first connecting tube 310, the second connecting tube 320, the second insulating layer 340, and the insulating sleeve 330 in the bipolar electric coil 1000 belong to the operating mechanism 300. The first connecting tube 310 is sleeved on the first electrode wire 1 and the first operating wire 4, and the first electrode wire 1 and the first operating wire 4 can be reliably connected; the second connecting tube 320 is sleeved on the second electrode wire 2 and the second operating wire 5, and the second electrode wire 2 and the second operating wire 5 can be reliably connected.

[0108] In some embodiments, the sheath 200 is a multi-chamber structure including at least two chambers, with the first control wire 4 and the second control wire 5 slidably passing through one of the chambers in the sheath 200.

[0109] In some embodiments, the sheath 200 is a single-chamber structure including a chamber, and the first control wire 4 and the second control wire 5 are slidably inserted inside the sheath 200 to enable the loop 100 to rotate.

[0110] In some embodiments, the sheath 200 is provided with an insulating portion 500. During the process of the snare 100 retracting into the sheath 200, the first working section 11 and the second working section 20 are insulated by the insulating portion 500. Short circuits or creepage can easily occur between the first and second working sections as the snare gradually retracts into the sheath. The embodiment of this application avoids this phenomenon by providing the insulating portion 500 to isolate and insulate them. The specific structural form of the insulating portion 500 is not limited, as long as it ensures insulation between the first working section 11 and the second working section 20 during the process of the snare 100 retracting into the sheath 200.

[0111] In some embodiments, referring to Figures 11 and 12, the insulating portion 500 can be a multi-cavity tube segment. The multi-cavity tube segment includes at least two chambers, such as a first chamber 501 and a second chamber 502, and the chambers are mutually insulated. The first electrode wire 1 and the second electrode wire 2 are slidably inserted into one of the chambers. As the first electrode wire 1 and the second electrode wire 2 are gradually retracted into the sheath 200, the first working section 11 and the second working section 20 are insulated from each other by the insulating portion 500, such as the multi-cavity tube segment, to prevent short circuits or creepage.

[0112] In some embodiments, the length M1 of the insulating portion 500 is greater than or equal to the shorter of the first working segment 11 and the second working segment 20, M2. The length M1 is the length of the insulating portion 500 along its own axial direction, and the length M2 is the length of the first working segment 11 and the second working segment 20 along their own axial directions. For example, the first electrode wire 1 is exposed from the first insulating layer 110 to form the first working segment 11, and the second electrode wire 2 forms the exposed second working segment 20. The exposed length of the second working segment 20 along its axial direction is greater than the exposed length of the first working segment 11 along its axial direction. In this case, the length M1 of the insulating portion 500 is greater than or equal to the length M2 of the first working segment 11.

[0113] In some embodiments, the insulating portion 500 is disposed at the distal end of the sheath 200. The distal end of the sheath 200 may be the end of the sheath 200, for example, the multi-lumen tube segment shown in FIG13 is located at the distal end of the sheath 200; or it may be a distal portion, i.e., a distal region, on the sheath 200, having a certain length, for example, the multi-lumen tube segment shown in FIG11 passes through the end region of the sheath 200.

[0114] In some embodiments, a rotating structure is provided between the insulating portion 500 and the sheath 200, allowing the insulating portion 500 to rotate about the axis of the sheath 200. The first electrode wire 1 and the second electrode wire 2 are slidably threaded through the insulating portion 500; for example, the first electrode wire 1 is threaded through the first chamber 501 of the multi-cavity tube segment, and the second electrode wire 2 is threaded through the second chamber 502 of the multi-cavity tube segment. When the first electrode wire 1 and the second electrode wire 2 rotate, they can drive the insulating portion 500 to rotate around the sheath 200, ensuring smooth rotation and preventing the first electrode wire 1 and the second electrode wire 2 from tangling during rotation.

[0115] In some embodiments, as shown in Figures 11 and 12, the rotating structure includes a receiving space 2010 disposed within the sheath 200, and an insulating portion 500 is at least partially disposed within the receiving space 2010, and the insulating portion 500 rotates relative to the receiving space 2010; the receiving space 2010 has a distal limiting portion 2011 and a proximal limiting portion 2012, and the insulating portion 500 is disposed between the distal limiting portion 2011 and the proximal limiting portion 2012. The distal limiting portion 2011 and the proximal limiting portion 2012 restrict the axial displacement of the insulating portion 500; in order to ensure the circumferential rotation of the insulating portion 500 within the receiving space 2010, there is a certain axial clearance between the insulating portion 500 and the receiving space 2010 in the axial direction and a certain circumferential clearance between the insulating portion 500 and the receiving space 2010 in the circumferential direction. The axial clearance and the circumferential clearance form a rotational clearance to enable the insulating portion 500 to rotate, and the rotational clearance should not be too large to avoid shaking.

[0116] In some embodiments, the distal limiting portion 2011 is formed by radially contracting the distal end of the sheath 200, or it may be a distal limiting tube disposed at the distal end of the sheath 200; the proximal limiting portion 2012 may be a proximal limiting tube disposed on the inner wall of the sheath 200; the sheath 200 is fixedly connected to the distal limiting tube and the proximal limiting tube, and the connection method includes, but is not limited to, threaded connection, interference fit, integral molding, welding, bonding, snap-fit, etc.

[0117] The distal limiting portion 2011 can be configured as a distal limiting tube, and the proximal limiting portion 2012 can be configured as a proximal limiting tube. In some embodiments, the distal limiting tube is made of insulating material, and the proximal limiting tube is made of insulating material or non-insulating material.

[0118] In some embodiments, as shown in Figures 13 and 14, the rotating structure includes a first rotating connector 600 with a protrusion 610 and a second rotating connector 700 with a recess 710. One of the first rotating connector 600 and the second rotating connector 700 is disposed in the insulating portion 500, and the other is disposed in the sheath 200. The protrusion 610 and the recess 710 are embedded and rotatably engaged. When the protrusion 610 and the recess 710 engage, the axial movement between the insulating portion 500 and the sheath 200 is restricted, while allowing the insulating portion 500 to rotate circumferentially about the axis of the sheath 200. To ensure the rotation of the insulating portion 500, a rotational clearance similar to that described above is also provided between the protrusion 610 and the recess 710.

[0119] In some embodiments, when the second rotary connector 700 is connected to the insulating portion 500, a recess 710 is formed in an axially spaced gap (not shown) between the second rotary connector 700 and the proximal end of the insulating portion 500; in some embodiments, as shown in FIG14, when the second rotary connector 700 is connected to the sheath 200, a recess 710 is formed in an axially spaced gap between the second rotary connector 700 and the distal end of the sheath 200.

[0120] For example, the protrusion 610 and / or the recess 710 can be a continuous ring structure or a broken ring structure formed by multiple protrusions, providing rotational fit between surfaces and between multiple points and surfaces, improving rotational stability, avoiding deformation, and preventing deflection.

[0121] In some embodiments, the first rotary connector 600 and the protrusion 610 are fixedly connected, and the second rotary connector 700 and the recess 710 are fixedly connected. The fixed connection methods include, but are not limited to, threaded connection, interference fit, integral molding, welding, bonding, snap-fit, etc.

[0122] The first rotary connector 600 is fixedly connected to either the insulating part 500 or the sheath 200, and the second rotary connector 700 is fixedly connected to the other insulating part 500 or the sheath 200. The fixed connection methods include, but are not limited to, threaded connection, interference fit, integral molding, welding, bonding, snap-fit, etc.

[0123] In some embodiments, as shown in Figures 13 and 15, the first rotary connector 600 is provided with an internal thread structure 601, and the insulating part 500 is provided with an external thread structure (not shown), and the first rotary connector 600 and the insulating part 500 are threadedly connected.

[0124] In some embodiments, as shown in Figures 13 and 16, the outer periphery of the second rotary connector 700 is provided with a barb structure 701, and the outer periphery of the second rotary connector 700 is interference-fitted with the inner wall of the sheath tube 200.

[0125] Referring to Figures 17 and 18, the first electrode wire 1 and the second electrode wire 2 may each include multiple wires 130. The wires 130 may be the same or different, for example, they may include a first wire 131 and a second wire 132 that are different from each other.

[0126] During operation, the fuse may melt due to excessive current or prolonged use.

[0127] In some embodiments, at least one of the first working segment 11 and the second working segment 20 includes an internal structure and an external structure. As shown in FIG17, the internal structure of the first working segment 11 is a first internal structure 111, and the external structure is a first external structure 112. As shown in FIG18, the internal structure of the second working segment 20 is a second internal structure 210, and the external structure is a second external structure 220.

[0128] The external structure at least covers a portion of the surface of the internal structure, and may completely cover it. Based on the cut surface, the external structure at least covers the surface of the internal structure facing the cut space 1001.

[0129] The melting point of the material of the outer structure is higher than or equal to that of the material of the inner structure. During the energization of the snare 100, the outer structure is subjected to current impact before the inner structure. Therefore, the high melting point of the outer structure allows it to better withstand high temperatures and protect the inner structure, preventing ablation or even breakage. Simultaneously, since the snare 100 needs to maintain its shape while being deformable during operation, the inner structure deforms more easily while maintaining its shape, ensuring that the snare 100 can smoothly retract into the sheath 200. Furthermore, when both the first working section 11 and the second working section 20 are retracted within the sheath 200 to completely sever the tissue, if there is no insulating portion between the two working sections, the high melting point material of the outer structure can also prevent melting due to breakdown or creepage.

[0130] Referring to Figure 17, the outer structure includes a plating 140 covering the inner structure. The first outer structure 112 may include only the plating 140; it may also include other structures, such as at least one filament 130.

[0131] In other embodiments, referring to FIG18, the internal structure includes at least one filament 130, and the external structure includes a plurality of other filaments 130 arranged sequentially along the circumference of the internal structure. The filament 130 included in the second internal structure 210 may be a first filament 131, and the filament 130 included in the second external structure 220 may be a second filament 132. The second external structure 220 may completely surround the second internal structure 210; or it may be used only to form the inner ring of the loop 100.

[0132] At least the outer structure is made of a high-melting-point material. The melting point of the high-melting-point material can be above 1800°C. Alternatively, the material of the outer structure may include at least one of tungsten, tantalum, rhenium, and molybdenum. Specifically, tungsten has a melting point of 3414°C, rhenium 3186°C, tantalum 3017°C, and molybdenum 2233°C. The material of the outer structure can be an alloy, such as a tungsten-rhenium alloy or a tungsten-tantalum alloy. The material of the inner structure may include iron, for example, 304 stainless steel. The first outer structure 112 and the second outer structure 220 may have the same material.

[0133] As shown in Figure 3, the proximal extension 12 at the first insulating layer 110 may consist only of the internal structure, or the distal end of the first insulating layer 110 may overlap with a section of the external structure.

[0134] When the external structure includes a coating 140, the coating 140 can be formed using physical vapor deposition or chemical vapor deposition. Exemplarily, the ratio of the thickness s of the coating 140 to the outer diameter d of the internal structure ranges from 0.005 to 0.015, for example, a ratio of 0.007, 0.009, 0.01, 0.012, or 0.014. This range can be from 0.008 to 0.01. The coating 140 can easily and completely cover the internal structure.

[0135] When the outer perimeter of the cross-section of the internal structure is approximately circular, the outer diameter can be the diameter of the smallest circumscribed circle. Referring to Figure 17, the outer surface of the first internal structure 111 is close to a cylindrical surface, and the radial difference δ is in the range of less than 0.09 mm, for example, it can be from 0.03 mm to 0.065 mm. Similarly, the outer perimeter of the coating 140 can be circular or approximately circular. The outer diameter of the working section can be equivalent to the characteristic dimension L2 along the perpendicular direction of the cutting surface, such as the first characteristic dimension of the first working section 11, and the second characteristic dimension of the second working section 20.

[0136] In some embodiments, the thickness of the plating layer 140 ranges from 1 μm to 5 μm. In some embodiments, the thickness of the plating layer 140 ranges from 2 μm to 4 μm. If the plating layer is too thin, it will be difficult to withstand high temperatures, which may cause the wire 130 to melt; if it is too thick, it will easily peel off from the internal structure when the electrode wire deforms. The thickness of the plating layer 140 may range from 2.5 μm to 3.5 μm, and exemplarily, from 3 μm to 3.5 μm.

[0137] The first internal structure 111 of the first working section 11 may include five to nine filaments 130. The outer diameter of the first internal structure 111 ranges from 0.25 mm to 0.35 mm. The second internal structure 210 of the second working section 20 may include ten to fourteen filaments 130, and the outer diameter of the second internal structure 210 ranges from 0.35 mm to 0.45 mm. Both external structures can be coated with a layer 140. When the polyp is cut by electricity, the filaments do not break, and the filaments retain their shape well.

[0138] For example, the first internal structure 111 of the first working section 11 includes seven filaments 130, for example, six filaments 130 may surround one filament 130, and the outer diameter of the first internal structure 111 is in the range of 0.3mm ± 0.02mm; the second internal structure 210 of the second working section 20 includes twelve filaments 130, and the outer diameter of the second internal structure 210 is in the range of 0.4mm ± 0.02mm.

[0139] Optionally, the first internal structure 111 of the first working section 11 includes ten to fourteen filaments 130, with an outer diameter ranging from 0.25 mm to 0.35 mm. The second internal structure 210 of the second working section 20 includes seventeen to twenty-one filaments 130, with an outer diameter ranging from 0.35 mm to 0.45 mm. When cutting polyps with electricity, the coiled filaments do not break, and the coiled filaments retain well.

[0140] For example, the first internal structure 111 of the first working section 11 includes twelve filaments 130, and the outer diameter of the first internal structure 111 is in the range of 0.3mm ± 0.02mm. The second internal structure 210 of the second working section 20 includes nineteen filaments 130, and the outer diameter of the second internal structure 210 is in the range of 0.4mm ± 0.02mm.

[0141] The cross-sections of the second working section 20 at different positions along the proximal and distal directions can be substantially the same. For example, the first section 21 may include a first internal section and a first external section, wherein the first internal section is at least a part of the second internal structure 210 and the first external section is at least a part of the second external structure 220.

[0142] Referring to Figures 19 and 20, the internal structure includes at least one filament 130, and the external structure includes a plurality of additional filaments 130 arranged sequentially along the circumference of the internal structure. Exemplarily, the filaments 130 of the external structure are wound and contact the internal structure in a left- or right-hand spiral according to the axial direction of the internal structure. The spiral directions of the filaments 130 of the internal structure and the filaments 130 of the external structure can be the same or different. The filaments 130 are easy to manufacture.

[0143] For example, two adjacent filaments 130 in the outer structure are in contact; they may also have a certain gap due to deformation or other reasons. The melting point of the filaments 130 in the outer structure is higher than or equal to the melting point of the filaments 130 in the inner structure. Optionally, the outer structure may include different filaments 130. For example, as shown in FIG20, in the first outer structure 112, the second filament 132 and the third filament 133 may be made of different kinds of materials.

[0144] When the first working section 11 and the second working section 20 have different outer diameters, the deformation state of the loop 100 may be unstable. By controlling the number and size of the wires 130, it is helpful to avoid the loop 100 from tilting. The number of wires 130 in the electrode wire can be between 3 and 38. Since the characteristic dimension of the second working section 20 is larger than that of the first working section 11, the second working section 20 is usually stiffer with the same number of wires 130. Based on the same outer diameter, increasing the number of wires 130 in the second working section 20 and decreasing the outer diameter of the wires 130 can reduce the stiffness of the second working section 20. For example, the number of wires 130 in the first working section 11 is less than the number of wires 130 in the second working section 20.

[0145] The first internal structure 111 of the first working section 11 may include two to four filaments 130, and the first external structure 112 of the first working section 11 may include eight to ten filaments 130. The outer diameter of the first working section 11 ranges from 0.25 mm to 0.35 mm. A second working section 20 can be designed accordingly. The second internal structure 210 of the second working section 20 includes six to eight filaments 130, and the second external structure 220 of the second working section 20 may include eleven to thirteen filaments 130. The outer diameter of the second working section 20 ranges from 0.35 mm to 0.45 mm. When the polyp is cut by electricity, the coiled filaments do not break. After cutting, the coils can be reopened to restore their original shape, exhibiting good retention.

[0146] Referring to Figure 20, the first internal structure 111 of the first working section 11 includes three filaments 130, and the first external structure 112 of the first working section 11 includes nine filaments 130. The outer diameter of the first working section 11 ranges from 0.3 mm ± 0.02 mm. The second internal structure 210 of the second working section 20 includes seven filaments 130, and the second external structure 220 of the second working section 20 includes twelve filaments 130. The outer diameter of the second working section 20 ranges from 0.4 mm ± 0.02 mm. The loop 100 provides good retention performance and increases the melting point of the electrode wire, preventing it from melting.

[0147] For example, the filament 130 of the outer structure is a tungsten wire. The diameter of the tungsten wire ranges from 0.05 mm to 0.12 mm. This prevents the tungsten wire from melting and also prevents the tungsten wire from being too stiff, thus avoiding poor retention of the sheath 100 and making it too difficult for the sheath 200 to retract.

[0148] Referring to Figures 3, 32, 34, 39, and 40, the diameter-to-length ratio of the cutting space 1001 ranges from 0.35 to 0.8, based on the cut surface of the snare 100 at its unfolded position until at least a portion of the snare 100 enters the sheath 200. Referring to Figure 32, the diameter-to-length ratio is the ratio of the radial dimension D1 of the cutting space 1001 to the axial dimension D2 of the cutting space 1001. The snare 100 maintains a good shape, fits snugly over the tissue to be cut, and maintains good cutting performance during the cutting process.

[0149] Referring to Table 1, which shows the product status of five working sections with coating 140, the outer diameter of the internal structure of each working section can be 0.25 mm. Furthermore, five sets of snares 100 are configured and the five working sections are used to test the cutting of the tissue, and the dimensions and cutting effect of the snares 100 at each stage are recorded.

[0150] Table 1: Control Group for the First Type of Internal Structure Test

[0151] Table 1-1, Test Record Table for Group 1.1

[0152] Table 1-2, Test Record Table for Group 1.2

[0153] Table 1-3, Test Record Table for Group 1.3

[0154] Table 1-4, Test Record Table for Group 1.4

[0155] Table 1-5, Test Record Table for Group 1.5

[0156] Referring to Table 2, which shows the product status of five additional working sections with coating 140, the outer diameter of the internal structure of these working sections can be 0.35 mm. Furthermore, five sets of snares 100 were configured and tested for cutting the tissue using these five working sections, recording the size and cutting effect of the snares 100 at each stage.

[0157] Table 2: Control Group for the Second Type of Internal Structure Test

[0158] Table 2-1, Test Record Table for Group 2.1

[0159] Table 2-2, Test Record Table for Group 2.2

[0160] Table 2-3, Test Record Table for Group 2.3

[0161] Table 2-4, Test Record Table for Group 2.4

[0162] Table 2-5, Test Record Table for Group 2.5

[0163] Referring to Table 3, which shows the product status of five additional working sections with coating 140, the outer diameter of the internal structure of these working sections can be 0.45 mm. Furthermore, five sets of snares 100 were configured and tested for cutting the tissue using these five working sections, recording the size and cutting effect of the snares 100 at each stage.

[0164] Table 3: Control Group for the Third Type of Internal Structure Test

[0165] Table 3-1, Test Record Table for Group 3.1

[0166] Table 3-2, Test Record Table for Group 3.2

[0167] Table 3-3, Test Record Table for Group 3.3

[0168] Table 3-4, Test Record Table for Group 3.4

[0169] Table 3-5, Test Record Table for Group 3.5

[0170] Test records show that because the coating 140 is thin, specifically between 1 μm and 5 μm, its thickness has almost no impact on the retention of the ring 100. However, when the coating 140 is too thin, for example, below 2 μm, it cannot provide sufficient heat resistance, leading to melting or cratering of the electrode wire. When the coating 140 is too thick, for example, s > 4 μm, the coating 140 is prone to detachment during the shrinkage and extension deformation of the electrode wire, resulting in melting or cratering of the electrode wire. A coating 140 thickness of 3 μm provides good temperature resistance, with no melting marks on the electrode wire and no detachment of the coating 140. Therefore, preferably, the coating 140 thickness is between 3 μm and 3.5 μm, and the thickness of the coating 140 can be 3 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, or 3.5 μm.

[0171] Referring to Figure 32, the axial dimension D3 of the first working section 11 is configured to correspond to the five embodiments shown in Table 4; and the axial dimension of the first section 21 is configured to be the same as D3.

[0172] Table 4: Control Group for the First Working Segment Test

[0173] The axial dimension D3 of the first working section 11 can be from 4 mm to 8 mm, preferably 6 mm.

[0174] Referring to Table 5, the outer diameter of the second electrode wire 2, i.e., the diameter of the coil, is 0.4 mm. First electrode wires 1 with different outer diameters are configured, and different numbers of wire bodies 130 with different diameters are designed. The second electrode wire 2 of group 5.4 can be configured with seven wire bodies 130, with three wire bodies 130 per wire body. The winding directions of the inner and outer wire bodies 130 can be different. Furthermore, the five groups of coils 100 are configured for tissue cutting tests, and the dimensions and cutting effects of the coils 100 at each stage are recorded.

[0175] Table 5: Control Group for Trap Test

[0176] Table 5-1, Test Record Table for Group 5.1

[0177] Table 5-2, Test Record Table for Group 5.2

[0178] Table 5-3, Test Record Table for Group 5.3

[0179] Table 5-4, Test Record Table for Group 5.4

[0180] Table 5-5, Test Record Table for Group 5.5

[0181] The external structure is made of tungsten wire. The more strands there are, the better the retention. However, the more strands there are, the thinner the diameter of each strand will be. When arcing occurs due to coiling, the temperature resistance will be insufficient, leading to melting.

[0182] Table 6: Contact Area Ratio Test Group

[0183] Referring to Table 6, the smaller the ratio of the contact area between the first working segment 11 and the tissue, i.e., the greater the difference in contact area, the higher the cutting efficiency. The contact area ratio can be further reduced by shortening the length of the first working segment 11. By setting the contact area ratio to be less than or equal to 0.14, cutting can be completed quickly.

[0184] Optionally, the contact area ratio ranges from 0.1 to 0.14, which is well-suited for cutting tissues of common sizes. A preferred contact area ratio range is 0.11 to 0.14, such as 0.12 or 0.13, to ensure the durability of the snare 100 when cutting large-diameter polyps.

[0185] Referring to Figures 1, 21, 22, and 23, the bipolar electric coil catcher 1000 may include a rotatable connection structure 400 and a handle. The handle may include a first operating part 6 and a second operating part 7. A sheath 200 is connected to the handle via the rotatable connection structure 400, and an operating mechanism 300 extends into the handle through the rotatable connection structure 400. The rotatable connection structure 400 may include a fixing member 410, a fixing block 420, and a sheath 430. The sheath 430 is fitted over the sheath 200, and the fixing block 420 is fixedly inserted inside the sheath 200. The fixing block 420 has a hole through which the first operating wire 4 and the second operating wire 5 can pass. The fixing member 410 is fitted over the sheath 430 and can be snapped and fixed to the first operating part 6. The proximal end of the sheath 430 may be configured as a T-shaped opening, axially confined by the fixing member 410 within the first operating part 6. The handle, operating mechanism 300, snare 100, and fixing member 410 are rotatable relative to the sheath 200. Subsequently, the first operating part 6 and the second operating part 7 in the handle are rotatably connected to the proximal end of the sheath 200, and the second operating part 7 is slidably connected to the first operating part 6.

[0186] Referring to Figures 23 and 24, the bipolar electric snare 1000 may further include a pin 71. Exemplarily, in the bipolar electric snare 1000, the second operating part 7 includes a base 70, a first ring structure 73, and a connecting piece 74. The base 70 may include the pin 71 and a seat 72. The pin 71 is disposed on the first operating part 6, the second operating part 7, or the sheath 200. The base 70 in Figure 23 is configured on the second operating part 7. Referring to Figure 24, the pin 71 includes a first contact 711 and a second contact 712 surrounding the first contact 711. An actuating wire is connected to the second operating part 7 and electrically connected to the pin 71. The proximal end of the first actuating wire 4 is fixed to the second operating part 7 and electrically connected to the first contact 711, and the proximal end of the second actuating wire 5 is fixed to the second operating part 7 and electrically connected to the second contact 712. The first contact 711 may be an active electrode contact, and the second contact 712 may be a passive electrode contact.

[0187] An injection-molded part may be provided between the first contact 711 and the second contact 712 for insulation and fixation. The bipolar electric coil 1000 may also include an active electrode tube and a passive electrode tube fixed to the injection-molded part. The first operating wire 4 is fixed to the active electrode tube and then electrically connected to the first contact 711, and the second operating wire 5 is fixed to the passive electrode tube and then electrically connected to the second contact 712.

[0188] The pin 71 is fixed to the base 72, which is connected to the first ring structure 73 via a connecting piece 74. The base 72 can slide synchronously with the first ring structure 73 and also rotates relative to the sheath 200. The base 72 and the first ring structure 73 can be directly connected or integrally formed. The user can smoothly operate the bipolar electric coil holder 1000. The base 70 is used to connect to the power supply 4000 (Figure 30). It can be connected to and limited to the power supply 4000 by the pin 71, or it can be detachably snapped into place by the base 72, with the pin 71 providing the electrical connection.

[0189] In some embodiments, the current starts from the first contact 711, passes through the first operating wire 4 to the first electrode wire 1, flows through the polyp to the second electrode wire 2, and then passes through the second operating wire 5 to the second contact 712.

[0190] Both the base 72 and the first ring structure 73 can be two-part snap-fit ​​structures, which clamp the first operating part 6, the pin 71, and the connecting piece 74 in the middle when snapped together. The handle structure of the bipolar electric coil device 1000 is simple and easy to assemble.

[0191] Referring to Figure 25, the base 72 and the first ring structure 73 can be an integral structure along the axial direction. A pin 71 is mounted on the second operating part 7. Referring to Figures 26 and 27, the pin 71 also includes an insulating tube 713. The insulating tube 713 can be an injection molded part. A first contact 711 is located at the distal end of the insulating tube 713. It should be understood that, based on the ring structure, the distal end of the insulating tube 713 in Figure 26 faces downwards. A second contact 712 is fitted onto the insulating tube 713, and the two contacts are insulated.

[0192] The insulating tube 713 has a conductive channel 7131 extending in the distal direction to the first contact 711 for inserting the first operating wire 4, which facilitates the electrical connection of the first operating wire 4 to the first contact 711.

[0193] The second operating wire 5 is electrically connected to the second contact 712 and can be welded in place. An insulating tube 713 is positioned on the base 72 in a limiting manner along its distal end. Exemplarily, the insulating tube 713 can be indirectly limited. The insulating tube 713 has a radially extending slot 7132 for inserting the second operating wire 5. Welding the second operating wire 5 to the second contact 712 helps to limit the position of the insulating tube 713.

[0194] Specifically, the second contact 712 includes a first limiting portion 7121 and a second limiting portion 7122 spaced apart, which can be used to clamp onto the mounting wall of the base 72. The limiting portion of the second contact 712 can be configured as a metal spring clip. The first limiting portion 7121 is compressed through the opening in the mounting wall and then springs open to achieve a snap-fit.

[0195] For example, referring to FIG28, the mounting wall has an elongated groove. The first limiting part 7121 can pass through the elongated groove along the long axis of the elongated groove, and after rotation, overlaps the mounting wall of the base 72 along the short axis of the elongated groove. Referring to FIG29, the second limiting part 7122 is also used to overlap the mounting wall of the base 72 along the short axis of the elongated groove.

[0196] Referring to Figure 30, the bipolar electric snare 1000 provided in this application can form an endoscope system 3000 together with an endoscope 2000 and a power supply 4000. The bipolar electric snare 1000 can be the aforementioned bipolar electric snare 1000, with the snare 100 within the field of view of the endoscope 2000. The power supply 4000 provides a high-frequency operating voltage to the snare 100. The endoscope system 3000 can efficiently remove, for example, polyp tissue.

[0197] Referring to FIG31, this application provides a method S100 for operating a bipolar electric snare. This method S100 may be based on the aforementioned bipolar electric snare 1000. Exemplarily, the bipolar electric snare 1000 utilized in this method S100 includes: a sheath 200 having a conduit and a snare 100. The snare 100 is disposed on the sheath 200 and is slidable along the conduit. The snare 100 has an extended position and a retracted position. The snare 100 includes a first electrode wire 1, a second electrode wire 2, and an insulating member 3. The distal ends of the first electrode wire 1 and the second electrode wire 2 are connected to the insulating member 3. A cutting space 1001 is formed between the first electrode wire 1 and the second electrode wire 2. A first working section 11 of the first electrode wire 1 is used to contact the tissue to be cut, and a second working section 20 of the second electrode wire 2 is used to contact the tissue to be cut. The contact area of ​​the first working section 11 is smaller than the contact area of ​​the second working section 20.

[0198] As shown in Figures 32 to 40, method S100 includes at least one of steps S110 to S160.

[0199] In step S110, the snare 100 is extended from the sheath 200 to the unfolded position. For smaller tissues to be cut, it may not be fully unfolded.

[0200] Step S120: Rotate the loop 100 based on the sheath 200. For example, the rotation can also be performed while the loop is retracted to a certain position, and the loop extends after the loop is in position.

[0201] Step S130: Place the loop 100 around the root of the tissue to be cut, as shown in Figure 32. This can be a combination of extension, rotation, and movement to ensure that the tissue to be cut passes through the cutting space 1001 and that the cutting surface lands at the root of the tissue.

[0202] In step S140, referring to Figures 32, 34, 39, and 40, the snare 100 is adjusted from the unfolded position to the retracted position. During the adjustment process, the tissue is cut.

[0203] Step S150: Apply a high-frequency working voltage to the first electrode wire 1 and the second electrode wire 2. The voltage can be applied after both the first electrode wire 1 and the second electrode wire 2 have contacted the tissue to be cut, and the high-frequency working voltage can be continuously applied during the adjustment process. During the adjustment process, the first working segment 11 and the second working segment 20 contact the tissue to be cut, so that the first working segment 11 cuts the tissue.

[0204] Referring to Figure 33, the current from the first electrode wire 1 passes through the tissue to the second electrode wire 2, forming a circuit loop.

[0205] Referring to Figure 35, current flows between the first working segment 11 and the second working segment 20. Based on the principle that current tends to flow along the path with lower resistance, the straight path between the first working segment 11 and the second working segment 20 is the shortest, meaning the current density is higher at the cutting surface Q, and decreases towards both sides. Since the inner surface 103 of the first working segment 11 and its direct contact area are smaller than the direct contact surface of the second working segment 20, the current is concentrated at the first working segment 11. Consequently, the dense current at the first working segment 11 can quickly generate heat, and the contacting tissue is vaporized and cut off more efficiently.

[0206] In step S160, the tissue is cut using the blade 31. Referring to FIG40, the insulating member 3 can also be retracted into the sheath 200. Inside the sheath 200, the first electrode wire 1 and the second electrode wire 2 can be spread out as much as possible based on their elasticity. On the one hand, insulation is achieved due to the first insulating layer 110, and on the other hand, the first electrode wire 1 and the second electrode wire 2 can maintain a substantial gap due to the constraint of the insulating member 3 and its own elasticity. In some embodiments, insulation between the first working segment 11 and the second working segment 20 in this working state can be ensured by providing an insulating portion 500.

[0207] During the process of the first electrode wire 1 and the second electrode wire 2 being retracted into the sheath 200 (refer to Figures 32, 35, and 39), the contact area between the first working section 11 and the tissue to be cut is always kept smaller than the contact area between the second working section 20 and the tissue to be cut.

[0208] The operation method of this application is easy to implement and the steps are simple; when used for cutting tissue, the cutting is efficient and thorough.

[0209] Referring to Figure 41, the diameter of the polyp tissue in Figure 41 is approximately 7 mm. For ease of measurement, an ex vivo polyp removal experiment can be performed. In one embodiment, the wire diameter of the first working segment 11 is 0.3 mm, and the wire diameter of the second working segment 20 is 0.41 mm. In the experiment, timing begins when the cutting starts with the application of electricity and ends when the polyp is completely removed. In this embodiment, the bipolar electric snare 1000 removes the polyp tissue in 3.5 seconds.

[0210] In a comparative example, the wire diameter of both the first working section 11 and the second working section 20 is 0.41 mm. The bipolar electric snare 1000 in this comparative example cuts a polyp of approximately 7 mm in size in 5 seconds. The cutting time of the embodiment of this application is shorter than that of the comparative example, and the cutting efficiency of the embodiment of this application is 43% higher than that of the comparative example. Furthermore, the cutting speed varies depending on the size of the polyp; the larger the polyp, the longer the total cutting time. The bipolar electric snare 1000 of this embodiment is faster than the comparative example in removing polyps of different sizes.

[0211] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0212] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A bipolar electric coil device, characterized in that, The bipolar electric coil includes: Sheath, having a conduit; and A snare, disposed on the sheath and capable of sliding along the pipe, has an extended position and a retracted position. The snare includes a first electrode wire, a second electrode wire, and an insulating member. The distal ends of the first electrode wire and the second electrode wire are connected to the insulating member. A cutting space is formed between the first electrode wire and the second electrode wire. A first working section of the first electrode wire is used to contact the tissue to be cut, and a second working section of the second electrode wire is used to contact the tissue to be cut. The contact area of ​​the first working section is smaller than the contact area of ​​the second working section.

2. The bipolar electric coil device according to claim 1, wherein, The snare has a cutting surface perpendicular to the direction, and the first characteristic dimension of the cross-section of the first working segment along the cutting surface perpendicular to the direction is smaller than the second characteristic dimension of the cross-section of the second working segment along the cutting surface perpendicular to the direction.

3. The bipolar electric coil device according to claim 1, wherein, The second working section includes a first section and a second section, and the snare also has a position where the second section is retracted into the sheath and the first section and the first working section are outside the sheath; the contact area of ​​the first section is greater than the contact area of ​​the first working section.

4. The bipolar electric coil device according to claim 3, wherein, The snare has a cutting surface perpendicular to the direction, and the first characteristic dimension of the cross-section of the first working section along the cutting surface perpendicular to the direction is smaller than the second characteristic dimension of the cross-section of the first section along the cutting surface perpendicular to the direction.

5. The bipolar electric coil device according to claim 2 or 4, wherein, The ratio of the first feature size to the second feature size is less than or equal to 0.

90.

6. The bipolar electric coil device according to claim 1, wherein, The ratio of the contact area of ​​the first working section to the contact area of ​​the second working section is less than or equal to 0.

14.

7. The bipolar electric coil device according to claim 2 or 4, wherein, The cross-sectional shape of the first working section and the cross-sectional shape of the second working section are both circular, and the first feature dimension and the second feature dimension are both the diameter of the circle.

8. The bipolar electric coil device according to claim 1, wherein, The snare also includes a first insulating layer that extends from the proximal end to the distal end of the first electrode wire and wraps around a portion of the first electrode wire. At least a portion of the first electrode wire is exposed from the first insulating layer to form the first working segment, which is located in the distal region of the first electrode wire and is positioned at least toward the cutting space.

9. The bipolar electric coil device according to claim 8, wherein, The second electrode wire is exposed to form the second working segment, and the exposed length of the second working segment along the axial direction of the second working segment is greater than the exposed length of the first working segment along the axial direction of the first working segment.

10. The bipolar electric coil device according to claim 1, wherein, The insulating element includes a cutting edge located between the first working section and the second working section, the cutting edge forming part of the cutting space.

11. The bipolar electric coil device according to claim 1, wherein, When the snare is in the retracted position, at least a portion of the insulating element is located within the conduit of the sheath.

12. The bipolar electric coil device according to claim 1, wherein, At least one of the first working segment and the second working segment includes an internal structure and an external structure, wherein the external structure at least covers a portion of the surface of the internal structure, and the melting point of the material of the external structure is higher than or equal to the melting point of the material of the internal structure.

13. The bipolar electric coil device according to claim 1, wherein, The sheath is provided with an insulating part, and during the process of the snare being retracted into the sheath, the first working section and the second working section are insulated by the insulating part; a rotating structure is provided between the insulating part and the sheath, and the insulating part rotates around the axis of the sheath.

14. A bipolar electric coil device, characterized in that, include: Sheath, having a conduit; and A snare, disposed within the sheath and capable of sliding along the conduit, has an extended position and a retracted position. The snare includes a first electrode wire, a second electrode wire, and an insulating element. The distal ends of the first and second electrode wires are connected to the insulating element, forming a cutting space between them. A first working section of the first electrode wire contacts the tissue to be cut, and a second working section of the second electrode wire contacts the tissue to be cut. The sheath has an insulating portion, and during the snare's retraction into the sheath, the first and second working sections are separated by the insulating portion. A rotating structure is provided between the insulating portion and the sheath, allowing the insulating portion to rotate around the axis of the sheath.

15. The bipolar electric coil device according to claim 14, wherein, The insulating portion is located at the distal end of the sheath.

16. The bipolar electric coil device according to claim 14, characterized in that, The rotating structure includes a receiving space disposed within the sheath, the insulating portion being at least partially disposed within the receiving space, and the insulating portion rotating relative to the receiving space.

17. The bipolar electric coil device according to claim 14, wherein, The rotating structure includes a first rotating connector with a protrusion and a second rotating connector with a recess. One of the first rotating connector and the second rotating connector is located in the insulating part, and the other is located in the sheath. The protrusion and the recess are embedded and rotated together.

18. The bipolar electric coil device according to claim 14, wherein, The insulating part is a multi-cavity tube segment, which includes at least two cavities and is mutually insulated from each other. The first electrode wire and the second electrode wire are slidably inserted into one of the cavities.

19. The bipolar electric coil device according to claim 14, wherein, The snare has a cutting surface perpendicular to the direction, and the first characteristic dimension of the cross-section of the first working segment along the cutting surface perpendicular to the direction is smaller than the second characteristic dimension of the cross-section of the second working segment along the cutting surface perpendicular to the direction.

20. The bipolar electric coil device according to claim 14, wherein, The second working section includes a first section and a second section, and the snare also has a position where the second section is retracted into the sheath and the first section and the first working section are outside the sheath; the contact area of ​​the first section is greater than the contact area of ​​the first working section.

21. The bipolar electric coil device according to claim 14, wherein, At least one of the first working segment and the second working segment includes an internal structure and an external structure, wherein the external structure at least covers a portion of the surface of the internal structure, and the melting point of the material of the external structure is higher than or equal to the melting point of the material of the internal structure.

22. A bipolar electric coil device, characterized in that, The bipolar electric coil includes: Sheath, having a conduit; and A snare, disposed on the sheath and capable of sliding along the pipe, the snare having an extended position and a retracted position, the snare comprising: Insulating components; A first electrode wire, with its distal end connected to the insulating member, has a first working section for contacting the tissue to be cut; and The second electrode wire is connected at its distal end to the insulating member. The second working section of the second electrode wire is used to contact the tissue to be cut. A cutting space is formed between the second electrode wire and the first electrode wire. At least one of the first working section and the second working section includes an internal structure and an external structure. The external structure at least covers a portion of the surface of the internal structure. The melting point of the material of the external structure is higher than or equal to the melting point of the material of the internal structure.

23. The bipolar electric coil device according to claim 22, wherein, The external structure includes a coating that covers the internal structure.

24. The bipolar electric coil device according to claim 23, wherein, The ratio of the thickness of the coating to the outer diameter of the internal structure ranges from 0.005 to 0.

015.

25. The bipolar electric coil device according to claim 23, wherein, The thickness of the coating ranges from 2 μm to 4 μm.

26. The bipolar electric coil device according to claim 23, wherein, The first internal structure of the first working section includes five to nine filaments, and the outer diameter of the first internal structure ranges from 0.25 mm to 0.35 mm. The second internal structure of the second working section includes ten to fourteen filaments, and the outer diameter of the second internal structure ranges from 0.35 mm to 0.45 mm.

27. The bipolar electric coil device according to claim 26, wherein, The first internal structure of the first working section includes seven filaments, and the outer diameter of the first internal structure ranges from 0.3 mm ± 0.02 mm. The second internal structure of the second working section includes twelve filaments, and the outer diameter of the second internal structure ranges from 0.4 mm ± 0.02 mm.

28. The bipolar electric coil device according to claim 23, wherein, The first internal structure of the first working section includes ten to fourteen filaments, and the outer diameter of the first internal structure ranges from 0.25 mm to 0.35 mm. The second internal structure of the second working section includes seventeen to twenty-one filaments, and the outer diameter of the second internal structure ranges from 0.35 mm to 0.45 mm.

29. The bipolar electric coil device according to claim 28, wherein, The first internal structure of the first working section includes twelve filaments, and the outer diameter of the first internal structure ranges from 0.3 mm ± 0.02 mm. The second internal structure of the second working section includes nineteen filaments, and the outer diameter of the second internal structure ranges from 0.4 mm ± 0.02 mm.

30. The bipolar electric coil device according to claim 22, wherein, The internal structure includes at least one filament; the external structure includes a plurality of other filaments arranged sequentially along the circumference of the internal structure.

31. The bipolar electric coil device according to claim 30, wherein, The filaments of the outer structure are wound and contact the inner structure in a left- or right-hand spiral according to the axial direction of the inner structure; adjacent filaments in the outer structure are in contact. The melting point of the filaments in the external structure is higher than or equal to the melting point of the filaments in the internal structure.

32. The bipolar electric coil device according to claim 30, wherein, The first internal structure of the first working section includes two to four filaments, the first external structure of the first working section includes eight to ten filaments, and the outer diameter of the first working section ranges from 0.25 mm to 0.35 mm. The second internal structure of the second working section includes six to eight filaments, the second external structure of the second working section includes eleven to thirteen filaments, and the outer diameter of the second working section ranges from 0.35 mm to 0.45 mm.

33. The bipolar electric coil device according to claim 32, wherein, The first internal structure of the first working section includes three filaments, the first external structure of the first working section includes nine filaments, and the outer diameter of the first working section is in the range of 0.3mm ± 0.02mm. The second internal structure of the second working section includes seven filaments, the second external structure of the second working section includes twelve filaments, and the outer diameter of the second working section ranges from 0.4 mm to 0.02 mm.

34. The bipolar electric coil device according to claim 22, wherein, At least the material of the external structure is a high melting point material.

35. The bipolar electric coil device according to claim 22, wherein, The contact area of ​​the first working section is smaller than the contact area of ​​the second working section.

36. The bipolar electric coil device according to claim 35, wherein, The snare has a cutting surface perpendicular to the direction, and the first characteristic dimension of the cross-section of the first working segment along the cutting surface perpendicular to the direction is smaller than the second characteristic dimension of the cross-section of the second working segment along the cutting surface perpendicular to the direction.

37. The bipolar electric coil device according to claim 35, wherein, The second working section includes a first section and a second section, and the snare also has a position where the second section is retracted into the sheath and the first section and the first working section are outside the sheath; the contact area of ​​the first section is greater than the contact area of ​​the first working section.

38. The bipolar electric coil device according to claim 22, wherein, The number of filaments in the first working section is less than the number of filaments in the second working section.

39. The bipolar electric coil device according to claim 22, wherein, The sheath is provided with an insulating part. During the process of the snare being retracted into the sheath, the first working section and the second working section are separated by the insulating part. A rotating structure is provided between the insulating part and the sheath, and the insulating part rotates around the axis of the sheath.

40. The bipolar electric coil device according to claim 22, wherein, When the snare is in the retracted position, at least a portion of the insulating element is located within the conduit of the sheath.

41. A method for operating a bipolar electric snare, said bipolar electric snare being a bipolar electric snare as described in any one of claims 1 to 40, wherein, The method includes: Extend the snare from the sheath to the deployed position; The snare is placed around the root of the tissue to be cut; Adjust the snare from the deployed position to the retracted position, wherein the first working segment and the second working segment contact the tissue to be cut; and During the adjustment process, a high-frequency working voltage is applied to the first electrode wire and the second electrode wire so that the first working segment cuts the tissue to be cut.

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