CN210962216U - Snare for tissue excision - Google Patents

Abstract

A snare for tissue excision comprises a hollow outer tube with a near end and a far end, a pull cable and a ferrule, wherein the pull cable is located in the outer tube and can move in a reciprocating mode along the direction of a longitudinal axis of the outer tube, the ferrule is arranged at the far end of the pull cable and is of a single-strand flat wire structure, the ratio of the thickness P of the cross section of the flat wire structure to the height Q of the flat wire structure is 1: 4-1: 1.5, the ferrule is axially symmetrical along the direction of the longitudinal axis, and strong bending portions are axially and oppositely arranged on two axial sides of the ferrule. Through the design, the non-pedicle or sub-pedicle polyp can be effectively and completely sleeved into the ring sleeve, the technical effect that the diameter is changed and the deformation is not generated is basically achieved, and the effect that the ring sleeve catches the relatively flat polyp is greatly improved.

Description

Snare for tissue excision

Technical Field

The utility model relates to the field of medical equipment, especially, relate to a snare for tissue excision.

Background

Endoscopic Mucosal Resection (EMR) refers to a technique of injecting a drug into the submucosa of a lesion (e.g., sessile polyp, flat or superficial sunken polyp, leiomyoma, esophageal, gastric, colon early cancer, etc.) to form a liquid cushion and then cutting a large block of mucosal tissue. Its advantage is that the focus of infection can be cut off under endoscope without operation.

Polyps can be clinically classified into: guangdong sessile polyps, sub-sessile polyps and sessile polyps. Pedicles mean roots, pedicles mean relatively slender polyps, and pedicled polyps are generally benign and common; without pedicles, there are no obvious roots, the shape is flat, and generally malignant diseases are more common; the sub-pedicular polyp morphology is between the two, bulging but the root pedicles are relatively unnoticeable. The traditional snare loop material is formed by weaving a plurality of strands of stainless steel round wires, the loop material is soft, the deformation resistance is poor, and the loop material has advantages when pedicle-free or sub-pedicle polyps are cut.

In the process of removing polyps by using a traditional electric snare, snares with different specifications are often used according to different sizes of focuses of patients, and the specifications of the commonly used snares comprise seven types such as 40mm, 35mm, 30mm, 25mm, 20mm, 15mm and 10 mm. Based on the structural limitation of the ferrule of the traditional snare, the diameter of the ferrule (the maximum distance between two axially symmetrical sides of the ferrule) is rapidly reduced and the original shape of the ferrule is lost when the ferrule is shrunk to an outer tube, so that the original shape of the ferrule cannot be maintained under different diameters to snare the polyp, and the polyp can only be snatched under the original size. Doctors usually need to pre-judge the size of the focus of a patient in the operation process, and then select snares with different specifications and sizes to perform EMR operation under an endoscope. However, in the actual operation process, a doctor may make an erroneous prediction on the size of a lesion, or may find a new polyp when continuing to check after cutting off a first polyp (or other lesions), and the difference between the diameter of the new polyp and the diameter of the first polyp is larger than that of the first polyp, so that the defect that the same snare cannot meet the use of polyps or lesions with different diameters exists, the doctor has to replace a snare with a new specification, the operation time is increased, and the economic burden of a patient is greatly increased.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a: aiming at the defects that the rigidity of a ferrule is low, pedicle-free or sub-pedicle polyps cannot be effectively and completely sleeved in the ferrule and the edge of the ferrule cannot be completely grabbed, so that lesion can not be completely excised at one time, the performance of grabbing the pedicle-free or sub-pedicle polyps is poor, and the same snare cannot meet the requirements of excising polyps or focuses of different diameters, the snare with the ferrule capable of continuously reducing the diameter is provided, and the snares of different diameters can be obtained by the snare.

To achieve the above object, there is provided a snare for tissue resection:

at least comprises the following structure: a hollow outer tube having a proximal end and a distal end; the pull cable is positioned in the outer pipe and can move back and forth along the longitudinal axis direction of the pull cable; a loop arranged at the far end of the pull cable, and the loop is pulled into or pushed out of the outer tube by moving the pull cable along the longitudinal axis direction, so that the inner loop area of the loop is changed; the fixing part is used for fixedly connecting the proximal end of the ferrule with the distal end of the inhaul cable; the ferrule is of a single-stranded flat wire structure, the ratio of the section thickness P to the height Q of the flat wire structure is 1: 4-1: 1.5, the ferrule is axially symmetrical along the longitudinal axis direction, reinforced bending parts are axially oppositely arranged on two axial sides of the ferrule, and the reinforced bending parts are preferably symmetrically arranged.

The utility model discloses an adopt the single strand flat filament structure and with this special design of thickness P and height Q ratio control in 1:4 ~ 1:1.5 this within range of lasso flat filament structure, for this defect of traditional stranded winding silk thread lasso easy deformation, the anti deformability of single strand flat filament structure is stronger, also can bear bigger power and not warp in the flat filament direction of height to push down polyp tissue edge more easily, effectively embolia the lasso completely with organizing, improve the efficiency of snatching the tissue. A large number of clinical tests show that when the P/Q value of the flat wire is less than 1:4, the snare is not sharp enough, and a doctor feels large resistance when cutting polyp; when the P/Q value of the flat wire is larger than 1:1.5, the thickness P in the flat wire structure is too large relative to the height Q, the deformation resistance of the bearing force in the height direction is greatly reduced, and the polypus cutting force is insufficient.

Further, the reinforced bending part is formed by pre-bending a ferrule flat wire structure, and the flat wire structure at the reinforced bending part has a strength enhancing structure.

Further, strengthen kink by the lasso flat filament structure and strengthen forming intensity reinforcing structure after handling through the fifty percent discount kink after certain angle of subtend bending in the coplanar, intensity reinforcing structure covers the material including the reinforcing, and the reinforcing covers the material and can be reinforcing solder and/or reinforcing coating, certainly the utility model discloses well intensity reinforcing structure can not contain the reinforcing and cover the material, only through strengthening bending the processing formation, and cover the material through adopting the reinforcing, like reinforcing solder, reinforcing coating can improve the anti deformation performance of strengthening the kink, improves the technical effect that the whole reducing of snare is indeformable. Compare in the present lasso structure that does not possess the kink of strengthening, the utility model provides a lasso slows down the trend that the form was considered to the center pin rapidly at the recovery in-process based on this kink of strengthening in the recovery process to the effect of the indeformable of reducing has basically been realized. Compare and do not set up strong kink or flat filament among the prior art and twist reverse the structure of buckling, the utility model discloses in with the flat filament in the coplanar opposite direction buckle the strong structure furthest of buckling who obtains ensure to bend position, form relatively stable at the recovery lasso in-process, the racket shape is maintained basically to the whole form of lasso.

Further, the ratio of the axial distance d1 between the strong bending part and the far end to the extension distance value L2 of the ferrule along the longitudinal axis direction is less than 1/2, wherein the axial distance d1 between the strong bending part and the far end of the ferrule is the length of the strong bending part between the axial projection position of the ferrule and the far end of the ferrule, and the extension distance value L along the longitudinal axis direction is the distance between the far end of the ferrule and the far end of the outer tube.

Further, the ratio of the diameter L1 of the loop of the snare to the extension distance value L2 of the loop along the longitudinal axis direction is 1: 4-1: 1.5, wherein the diameter L1 of the loop of the snare is the maximum distance between two axially symmetrical sides of the loop, and the extension distance value L2 of the loop along the longitudinal axis direction is the distance between the farthest end of the loop and the farthest end of the outer tube.

When the snare cuts off tissues, the ferrule is pulled into the outer tube from the far end to the near end, when the ferrule continuously enters the outer tube, the diameter of the ferrule of the snare is gradually reduced, the shape of the ferrule basically keeps a shape similar to a racket shape in the ratio gradual change process of L1 and L2 and before the ferrule sleeves the tissues, the shape of the ferrule is not deformed due to the fact that the reinforced bending part in the ferrule has the bending characteristic, and therefore the purpose that the diameter of the ferrule is not deformed is achieved.

Further, the ratio of L1 to L2 is 1: 3-1: 2.34, and the numerical range of L1 is 10 mm-40 mm.

Further, the two side flat wire structures with the axially symmetric ferrule are respectively provided with an arc-shaped section flat wire structure and a straight line section flat wire structure at least, and the reinforced bending part is located at the transition position of the arc-shaped section flat wire structure to the straight line section flat wire structure.

Further, the ratio of the cross-sectional thickness P to the height Q of the ferrule flat wire structure is 1: 3-1: 2.

Further, the cross section of the flat wire structure is rectangular or sector-shaped with an opening facing the longitudinal axis direction of the ferrule.

When the section of the flat wire structure is rectangular, the whole ferrule is similar to an I-steel structure, can bear larger force and is not easy to deform in the direction vertical to the plane of the ferrule, so that larger holding force can be provided, polyp tissues can be pressed more easily, and the tissues are effectively and completely sleeved in the ferrule. When the section of the flat wire structure is in a fan-shaped shape (similar to a C shape) with the opening facing the longitudinal axis direction of the ferrule, the polyp tissue in the ferrule can be easily fastened and grasped by the arc-shaped opening facing the inner side of the ferrule, and the upper end and the lower end of the flat wire in the height direction are arc-shaped curved surfaces, so that the ferrule is adaptive to the radian of the inner wall of the outer tube, and when the ferrule slides in the outer tube in a reciprocating manner, the smoothness is greatly improved.

Furthermore, scales are arranged on the ferrule. The fixing part is a riveting pipe which is arranged outside the fixed connecting end of the ferrule and the inhaul cable and is positioned inside the outer pipe. The ferrule is formed by shaping medical stainless steel, nickel-titanium alloy and cobalt-chromium alloy.

To sum up, owing to adopted above-mentioned technical scheme, the beneficial effects of the utility model are that:

1) the utility model discloses an optimize lasso silk material structure for doctor pushes down the polyp through this structure more easily in clinical, will feel the meat and carry completely and draw up, to flat no base of a fruit or sub base of a fruit polyp very much, overlaps the focus completely, thoroughly in the snare more easily, thereby guarantees the more thorough of polyp excision.

2) Further, the utility model provides a snare ware of tissue excision of similar racket type sets up strong kink structure through the lasso, realizes lasso diameter gear adjustable technological effect, when the different diameter focus tissues are got in the cover, the supporting role of strong kink is better in the lasso, deformation is more nimble. Meanwhile, due to the bending characteristic of the reinforced bending part, the shape of the ferrule is basically not changed due to the diameter change of the ferrule in the process of extracting tissues, and the shape of the ferrule is always similar to a racket shape, so that when the focuses of different diameters are cut, the snares of different specifications do not need to be repeatedly replaced, and the aim of cutting the focuses of different diameters by using one snare is fulfilled.

3) In addition, when the two ends of the ferrule are drawn into the outer tube, the two ends of the ferrule in the height direction are basically the same as the relative positions outside the outer tube, the two side edges of the ferrule are placed in parallel, the sum of the thicknesses of the flat wires on the two sides of the ferrule is smaller than the diameter of the outer tube, and when the ferrule is drawn in and drawn into the outer tube, the sliding process of the ferrule in the outer tube is smoother.

Drawings

FIG. 1 shows a schematic view of the ferrule in different gears;

FIG. 2 shows a schematic view of the distal end of a snare with a ferrule having a tail silver weld and a rivet tube;

FIG. 3 shows a schematic view of the construction of the reinforced bend 5 in the snare;

FIG. 4 shows a schematic of the ferrule noting the L1 and L2 positions;

FIG. 5 shows a perspective view of a flat filament configuration with a rectangular cross-section;

FIG. 6 shows a thickness and height plot for a flat wire structure having a rectangular cross-section;

FIG. 7 is a perspective view of a flat filament configuration with a cross-section in the shape of a fan ring;

FIG. 8 shows a thickness and height plot for a flat wire configuration with an arc-shaped cross-section;

FIG. 9 shows a schematic of the maximum travel of the handle;

FIG. 10 shows a snare loop pressure test tooling diagram;

figure 11 shows a cross-sectional view of 3 x 3 multi-strand braided wire in the prior art;

figure 12 shows a cross-sectional view of a prior art 1 x 7 multi-strand braided wire.

Reference numerals:

1-ferrule 2-tail silver welding spot 3-riveting tube 4-inhaul cable 5-reinforced bent part 6-outer tube

7-handle 8-control slide block

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The utility model discloses well snare's working process: as shown in figures 1, 2 and 9, firstly, a snare with an outer tube of a proper length is selected according to a focus position of a patient, then the snare is placed in a working channel of the endoscope, the distal end (the distal end is the end opposite to an external operation end and positioned in the human body) of the outer tube of the snare is placed on the focus position, according to the diameter of the polyp of the focus position, the diameter of a loop 1 of the snare is adjusted to be slightly larger than the diameter of the polyp by adjusting a control slide block 8 (shown in figure 9) on a handle 7 of the snare, then the loop 1 of the snare is sleeved on a pedicle of the focus, and the transverse plane of the loop 1 is ensured to be approximately parallel to the transverse plane of the focus. After the ferrule 1 is placed, the control slider 8 fixedly connected with the stay cable 4 on the sliding handle 7 pulls the stay cable 4 towards the near end, the stay cable 4 drives the ferrule 1 to retract into the outer tube 6, at the moment, the diameter of the ferrule 1 is reduced, but the shape of the racket of the ferrule 1 is basically kept unchanged. After the collar 1 is partially received in the outer tube 6, the polyp is tightened and protrudes above the collar 1. The high frequency current of the active device (not shown) coupled to the snare is now turned on and the polyp is cut off under the influence of the high frequency current. If the patient needs to continuously cut polyps or focuses with other diameters, the sliding block 8 on the sliding handle 7 can be used for driving the pull rope to further change the diameter of the loop of the snare, the loop 1 is placed at a new focus to be cut, tissue cutting is continuously carried out, and the new snare with other specifications does not need to be replaced.

The utility model discloses well snare's theory of operation: as shown in figure 1, after the ferrule 1 is slowly pulled back and enters the outer tube 6, before a tight tissue (a pedicled polyp, a sessile polyp and the like) is held, the bendable and strong bending parts 5 which are symmetrically arranged on both sides of the racket-shaped ferrule 1 along the axial direction of the longitudinal axis are close to each other, and the ferrule 1 is synchronously reduced in the length direction and the radial direction, so that the overall appearance of the ferrule 1 basically keeps a shape similar to a racket, and polyps or focus tissues with different diameters can be easily picked up under different ferrule diameters. Wherein, strengthen kink 5 by 1 flat filament structure of lasso behind certain angle of subtend bending in the coplanar, strengthen through the fifty percent discount kink and form intensity reinforcing structure after handling, intensity reinforcing structure is reinforcing solder and/or reinforcing coating, 1 axial symmetry's of lasso both sides flat filament structure has an segmental arc flat filament structure and a straight line section flat filament structure respectively at least, strengthen kink 5 is located segmental arc flat filament structure is to straightway flat filament structure transition position. Based on the structure shown in fig. 1-4, the preferred structure of the present invention is a straight section located at the proximal end of the ferrule, and an arc section located at the distal end of the ferrule, wherein the proximal end of the straight section is fixedly connected with the distal end of the arc section to form a strong bending portion capable of bending.

In clinical practice, the doctor is when using the utility model provides a snare, pushes down the polyp with the lasso of flat filament shape more easily, and will feel the meat and carry completely and draw up, to flat polyp very much, more easily completely overlaps the focus in the snare completely to ensure that the polyp is amputated cleaner, prevent that the polyp excision is incomplete. The polyp can be tightly sleeved and then can be electrified for thermal cutting, and the polyp thermal resection of the snare under the endoscope is realized.

Example one

1-3, a snare for tissue resection includes at least the following: a hollow outer tube 6 having a proximal end and a distal end; a pulling cable 4 which is positioned in the outer tube 6 and can move back and forth along the longitudinal axis direction; the loop 1 arranged at the far end of the inhaul cable 4 pulls in or pushes out the loop 1 from the outer tube 6 by moving the inhaul cable 4 along the longitudinal axis direction, so as to change the loop area in the loop 1, the far end of the inhaul cable is provided with a fixing part for fixedly connecting the near end of the loop 1 and the far end of the inhaul cable 4, the fixing part is preferably a riveting tube 3 arranged outside the joint end of the loop 1 and the inhaul cable 4 and positioned in the outer tube 6, and other conventional fixed connecting means such as welding can be adopted. In addition, as shown in fig. 2, in order to improve the stability of the overall configuration of the ferrule and better realize the technical effect of non-deformation of variable diameter, a tail silver solder joint 2 of the ferrule is arranged at the far end position of a fixing part formed by the ferrule 1 and the cable 4 and used for pre-fixing the flat wire structures at two axially symmetrical sides of the ferrule, besides silver welding, other conventional fixed connection modes in the prior art can be adopted, the flat wires at two sides of the near end of the ferrule 1 are pre-fixed, and then the flat wires at two sides of the ferrule 1 are integrally and fixedly connected with the cable 4, so that the deformation resistance of the near end of the ferrule is improved, sufficient supporting force can be provided for the bending process of the reinforced bending part on the ferrule, and the technical effect of non-deformation of variable diameter of the ferrule is better.

The ferrule 1 is of a single-stranded flat wire structure, the ratio of the thickness P to the height Q of the flat wire structure is 1: 1.5-1: 4, the ferrule 1 is axially symmetrical along the longitudinal axis direction, and two sides of the axially symmetrical ferrule are respectively provided with a reinforcing bent part. The ferrule 1 is preferably formed of one or more of stainless steel, nitinol, cobalt-chromium alloy, and the like, although other materials that can be used in the body in the prior art can be used. In this embodiment, the overall rigidity of the ferrule of the single-strand flat wire structure is much higher than that of the ferrule structure formed by the conventional multi-strand round wires, mainly because: the traditional ferrule is usually formed by weaving a plurality of round wires, and 3 × 3 (three wires respectively formed by weaving three filaments, see fig. 11) or 1 × 7 (three wires formed by weaving a central filament and six filaments surrounding the central filament, see fig. 12) is adopted to weave the specification, the total outer diameter is controlled within 0.4mm, for example, the 1 × 7 multi-strand ferrule is formed by weaving 7 round wires, the diameter of each round wire is about 0.16mm, the diameter of each round wire is smaller, and the corresponding deformation resistance is smaller; and the utility model discloses well single strand flat filament lasso silk cross-section height is 0.18 ~ 0.48mm, and the thickness in flat filament cross-section is about 0.12 ~ 0.2mm, and wherein, thickness is about 0.2mm when preferred lasso silk cross-section height is about 0.4mm, and thickness is about 0.127mm when highly being about 0.381 mm. Compare in traditional stranded circle silk structure, the utility model discloses well single strand flat filament structure that adopts has more excellent anti deformability, can provide stronger gripping power to the focus tissue.

As shown in fig. 5 and 6, the cross section of the flat wire structure may be rectangular, and when the cross section of the flat wire structure is rectangular, the whole ferrule is similar to an i-steel structure, and can bear a larger force in a direction perpendicular to the plane of the ferrule without being easily deformed, so as to provide a larger holding force, so that the polyp tissue can be more easily pressed, and the tissue can be effectively and completely nested into the ferrule. As shown in fig. 7 and 8, the cross section of the flat wire structure can be in a fan-shaped ring shape with the opening facing the longitudinal axis direction of the ferrule, when the cross section of the flat wire structure is in a fan-shaped ring shape with the opening facing the longitudinal axis direction of the ferrule (similar to a C-shaped), the arc-shaped opening facing the inner side of the ferrule is easier to fasten and grasp the polyp tissue in the ferrule, and because the upper end and the lower end in the height direction of the flat wire are in arc-shaped curved surfaces, the ferrule is adapted to the radian of the inner wall of the outer tube, and when the ferrule slides back and forth in the outer.

As shown in fig. 10, a schematic diagram of a tool for testing the bearing pressure of a snare loop wire is shown, one end of a loop wire structure to be tested is fixed on a fixed tool structure, the other free end is used as a test point, the distance between the test point and the fixed point of the tool is 20mm, and after pressure is applied to the test point, the free end after the loop wire is deformed reaches a certain compression distance and the pressure required to be applied by the free end is recorded. The larger the pressure value is, the better the pressure holding performance is. Table 1 is a table of different parameters of the flat-wire structured ferrule and the existing 1 × 7 gauge ferrule, and a parameter comparison table of the strength percentages corresponding to the ferrules with different gauges.

TABLE 1

The abscissa values in the first 6 rows and 5 columns in table 1 represent the ratios of the thickness P to the height Q of the flat filament section, which are 1:1.5, 1:2, 1:3 and 1:4 (corresponding to specific dimensions of 0.12mm/0.18mm, 0.20mm/0.40mm, 0.127mm/0.381mm and 0.12mm/0.48mm, respectively), the ordinate values represent the compression distance of the free end at the time of testing the ferrule (deflection distance after the ferrule is stressed in the direction perpendicular to the thickness direction), the two-dimensional value of the intersection area between the abscissa and the ordinate refers to the pressure (in N) required to be exerted when the free end of the ferrule corresponding to the PQ value deviates from 2mm and 4mm … … 10mm, and the larger the same compression distance indicates the better pressure holding performance of the snare made of the ferrule filament with the size.

The 6 th column in the table is that the prior art adopts 7 round wires to weave a finished product of a 1 × 7 specification ferrule (the part of the end part of the snare which sleeves the polyp), and the total external diameter of the cross section of the wire of the ferrule is about 0.4 mm; column 6 specifically means that when the conventional multi-strand round wire ferrule is subjected to a pressure test, the applied pressure required for the free end to deviate by 2mm and 4mm … … 10mm is 0.04N, 0.07N, 0.10N, 0.12N, and 0.17N, respectively, when the ferrule wire is pressed by 2mm, 4mm, 6mm, 8mm, and 10mm (deflection distance perpendicular to the length direction). When the free end of the ferrule wire with the specification of 1 x 7 in the prior art deviates 10mm and the stressed pressure is 0.17N as a reference stress value, the strength percentage is set to be 100%, the deviation of the same free end of 10mm is obtained by reverse deduction, the applied pressures required by flat wires with different PQ sizes are respectively 0.15N, 1.05N, 0.30N and 1.10N, and compared with the strength percentage of the ferrule with the specification of 1 x 7 in the prior art, the strength percentages of the ferrule wires with the different specifications are respectively 88%, 618%, 176% and 647%. It can thus be seen that:

1) when the cross section P/Q value of the flat wire is 1:1.5, the strength of the looped wire is weak when P is less than 0.1mm, and taking the flat wire with P X Q of 0.12mm X0.18 mm as an example, compared with the looped wire of the prior art 1X 7, the strength percentage is 0.15N/0.17N-88%, which is close to 100%, and the larger the Q value is, the lower the P/Q ratio is, and the higher the strength percentage is.

2) When the P/Q value of the cross section of the flat wire is 1:4, although the strength of the flat wire is enough, the height of the flat wire is too large (0.48mm), which is 0.4mm larger than the total outer diameter of the braided round wire of the ferrule with the specification of 1 x 7 in the prior art, and the flat wire is easy to cause large cutting wound in clinical operation and is not sharp in cutting, so the flat wire is not suitable for clinical use.

Therefore, the P/Q value range of the section of the flat wire in the utility model is preferably more than 1:4 and less than 1:1.5, and P, Q should satisfy 0.1mm < P < Q <0.48 mm.

Example two

As shown in figures 3 and 4, on the basis of the first embodiment, the ferrule structure further comprises a reinforced bending part 5 which is arranged along the longitudinal axis of the ferrule in an axially symmetrical manner, as shown in figure 4, the maximum distance between two axially symmetrical sides of the ferrule is defined as the ferrule diameter L1 of the snare, the distance between the farthest end of the ferrule and the farthest end of the outer tube is defined as the protrusion distance value L2 of the ferrule along the longitudinal axis direction, the ratio of L1 to L2 is preferably 1: 1.5-1: 4, and tables 2 and 3 are tables for different parameters of L1, L2 and L1/L2 in the invention.

TABLE 2

The abscissa in Table 2 is the ratio of L1 to L2 in four scales of 1:1.5, 1:2.34, 1:3, 1:4, respectively, and the ordinate represents the snare loop diameter L1 value, and the two-dimensional data of the intersection region in the table represents the L2 (in mm) value.

TABLE 3

In table 3, the abscissa represents the ratio of L1 to L2, the ordinate represents the value of snare loop diameter L1, the cross two-dimensional value represents L3 (in mm), where L3 represents the maximum travel of the control slider 8 on the handle 7 (see fig. 9), L3 generally corresponds to the human finger controllable size limit.

As can be seen from tables 2 and 3:

1) when the diameter of the ferrule L1 is 20, L2 corresponding to L1/L2 is 1:1.5, which results in a smaller stretching stroke and a too short variable stroke, which is clinically unsuitable, so that a ferrule L1/L2 smaller than 1:1.5 is not suitable.

2) When the diameter L1 of the ferrule is 40, the maximum movable stroke L3 of the slider is 240mm, and the stroke is large (the maximum stroke is not more than 120mm in practical use), so that the operation is not convenient for a human hand.

3) When the diameter L1 of the ferrule is set in the range of 20-40 mm, it can be seen that L1/L2 is more appropriate between 1:1.5 and 1:4 according to the corresponding parameters in the table.

In summary, according to the above tables 2 and 3, in clinic, the snare loop diameter L1 is 30mm, and when 40mm is used, L1/L2 is preferably 1: 1.5-1: 2.34, when L1 is 20mm, and when 30mm is used, L1/L2 is selected to be 1: 2.34-1: 4, and L1/L2 is not suitable for clinical use.

In the first or second embodiment, the reinforced bending portion 5 has a reinforced bending structure, so that a bending inflection point can be basically maintained in the deformation process of the ferrule, and the shape of the ferrule is basically kept unchanged in the shape of the racket in the tissue grasping process of the ferrule, thereby achieving the technical effect of reducing the diameter and preventing the deformation. The reinforced bending part 5 is formed by a ferrule flat wire structure in the same plane after oppositely bending for a certain angle and reinforcing the bent part, wherein the reinforced structure is preferably reinforced solder or a reinforced coating layer, the solder is preferably made of a metal material which is difficult to break and flexible, such as silver, so as to form a silver solder layer, and the reinforced bending part 5 has enough bending stability and is difficult to break in the deformation process.

TABLE 4

As shown in table 4, the flat wire lasso product that does not possess the strong kink through the current conventionality of test, certain symmetry are equipped with the flat wire lasso product that has the angle of torsion and the utility model discloses in have the flat wire lasso of strong kink return back the in-process lasso diameter change value of contracting, further prove the utility model discloses well lasso realizes the indeformable beneficial effect of reducing basically. In the test process, the slider moves so that the lasso contracts the in-process to the near-end on the handle, and when the slider moved different distances, the lasso diameter in three kinds of products was measured respectively, can see out through the comparison, the utility model discloses well lasso diameter reduces the trend and compares and obviously slows down in two other products, and is especially obvious when the slider moved this distance of 5-20mm, and this displacement is just corresponding the lasso and snatchs the important node of organizational process, and this in-process lasso diameter reduces the reduction of speed, can provide sufficient time and space for the lasso and fully adjust and snatch the polyp tissue, promotes the gripping organizational ability of lasso greatly.

It is thus clear that compare in the present lasso structure that does not possess the kink of consolidating, the utility model provides a lasso slows down the trend that the form was drawn close to the center pin rapidly at the recovery in-process based on the characteristic of bending of this kink of consolidating at the recovery in-process to the effect of the indeformable of reducing has basically been realized. Compare and do not set up strong kink or flat filament among the prior art and twist reverse the structure of buckling, the utility model discloses in with the flat filament in the coplanar opposite direction buckle the strong structure furthest of buckling who obtains ensure to bend position, form relatively stable at the recovery lasso in-process, the racket shape is maintained basically to the whole form of lasso, effectively promotes the gripping tissue ability of lasso.

EXAMPLE III

Based on the first embodiment or the second embodiment, two axially symmetric sides of the ferrule respectively include at least one arc-shaped section flat wire structure and one straight-line section flat wire structure, and the reinforced bending portion 5 is used for fixedly connecting the end portions of the two sections of flat wire structures and forming a bendable structure, wherein any one of the two sections of flat wire structures is a straight line section or an arc-shaped section extending along the length direction of the flat wire, and the position of the reinforced bending portion 5 is preferably the transition position from the straight line section to the arc-shaped section. The ferrule can be kept before tissues such as polyps are taken out, the bending characteristic of the bent part is strengthened, the space between two flat wires which are axially symmetrical on two sides of the ferrule is not closed quickly when the ferrule enters the outer tube, and the overall shape of the ferrule is basically maintained stable. As shown in fig. 3 and 4, the utility model discloses distal end is straight section, near-end be the segmental arc in the preferred lasso, and the near-end of straight section constitutes strong kink 5 with the distal end transition region of segmental arc promptly, and the advantage of design like this lies in that the lasso structure is simple relatively, reliable and stable, and can realize that the lasso form is racket shape basically at gripping tissue in-process, reaches the technical effect that gripping tissue in-process reducing is indeformable.

In this embodiment, a ratio of a distance d1 (as shown in fig. 4) between the strong bending portion and the distal end of the ferrule to a protrusion distance L2 of the ferrule along the longitudinal axis direction is less than 1/2, wherein a distance d1 between the strong bending portion and the distal end of the ferrule is a length between an axial projection position of the strong bending portion and an axial projection position of the ferrule, and a protrusion distance L of the ferrule along the longitudinal axis direction is a distance between the distal end of the ferrule and the outer tube.

TABLE 5

As shown in table 5, the flat wire ferrules 1/2, 1/4 and 1/6 respectively have diameter variation values in the retraction process through testing d 1/L2, so as to compare the beneficial effect difference of the present invention that the strong bending portion in the ferrule realizes variable diameter and no deformation at different positions, during the testing process, the slider on the handle moves towards the near end to make the ferrule retract, when the slider moves different distances, the ferrule diameters at different positions of the three strong bending portions are respectively measured, it can be seen through comparison that the slow deformation effect of the strong bending portion is strongest when d 1/L2 is 1/4, the stronger bending portion is closer to the middle portion or the far end portion of the ferrule, the deformation resistance is correspondingly weakened, and through repeated testing, when 1/6< d 1/L2 <1/2, the slow deformation ability of the strong bending portion is strongest.

Example four

On the basis of the embodiment, the sleeve ring is provided with scales, the laser is used for marking the side face of the flat filament to serve as a measuring scale, a doctor can compare the size of polyp or lesion under an endoscope better conveniently, the size of the lesion is estimated accurately, the size of polyp is stored accurately by video screenshot, and original accurate data are provided for subsequent accurate treatment. When the lesion excision is carried out, the scales on the snare can help a doctor to estimate the size of the lesion, so that the doctor can accurately judge the volume of the lesion, and the judgment error is avoided.

EXAMPLE five

The height of the ferrule flat wire structure is 0.38mm, the thickness is 0.13mm, when the flat wires on the two sides of the ferrule are arranged in the outer tube in parallel from left to right, the sum of the thicknesses of the flat wires is 0.26mm, the diameter of the inhaul cable is 0.8mm, and the inner diameter of the outer tube is 1.5 mm.

Therefore, when the two ends of the ferrule are pulled into the outer tube, the two ends of the ferrule in the height direction are basically the same as the relative positions outside the outer tube, the two side edges of the ferrule are placed in parallel, the sum of the thicknesses of the flat wires on the two sides of the ferrule is smaller than the diameter of the outer tube, and when the ferrule is folded and pulled into the outer tube, the sliding process of the ferrule in the outer tube is smoother.

EXAMPLE six

On the basis of the embodiment, the utility model discloses a set up the strong kink, realized that lasso diameter L1 is by the snare of 10mm to the specification that 40mm varies, the snare of every specification increase and decrease the minimum scale of gear is 5mm or 10mm, can realize completely that the snare of same specification carries out the demand of excision to the polyp of different diameters, wherein the lasso diameter L1 of lasso ware indicates the biggest interval in both sides of lasso axial symmetry.

For example, during operation, the size of the provided snare is 40mm, when the snare enters the vicinity of an operation part, the difference between the diameter of the polyp and the expected size is found to be large, the diameter is only about 22mm, at this time, before the polyp is sleeved, the snare is operated in advance, the diameter L1 of the snare is changed to 30mm, at this time, the snare still keeps the original racket shape, then, the polyp is sleeved by the snare loop in the state at this time, the diameter of the snare loop at this time is reduced, and the process of grasping the polyp tissue is completed.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims (10)

1. A snare for tissue resection comprising at least the following:

a hollow outer tube having a proximal end and a distal end;

the pull cable is positioned in the outer pipe and can move back and forth along the longitudinal axis direction of the pull cable;

a loop arranged at the far end of the pull cable, and the loop is pulled into or pushed out of the outer tube by moving the pull cable along the longitudinal axis direction, so that the inner loop area of the loop is changed;

the fixing part is used for fixedly connecting the proximal end of the ferrule with the distal end of the inhaul cable;

the method is characterized in that:

the ferrule is of a single-stranded flat wire structure, the ratio of the section thickness P to the height Q of the flat wire structure is 1: 4-1: 1.5, the ferrule is axially symmetrical along the longitudinal axis direction, and reinforced bending parts are axially and oppositely arranged on two axial sides of the ferrule.

2. A snare according to claim 1, wherein:

the reinforced bending part is formed by pre-bending a ferrule flat wire structure, and the flat wire structure at the reinforced bending part has a strength reinforcing structure.

3. A snare according to claim 2, wherein:

the reinforced bending part is formed by a ferrule flat wire structure in the same plane after oppositely bending for a certain angle and reinforcing the bending part, and the strength reinforcing structure comprises a reinforcing cover material.

4. A snare according to claim 1, wherein:

the ratio of the axial distance d1 between the reinforced bending part and the far end to the extension distance L2 of the ferrule along the longitudinal axis direction is less than 1/2, wherein the axial distance d1 between the reinforced bending part and the far end of the ferrule is the length of the reinforced bending part between the axial projection position of the ferrule and the far end of the ferrule, and the extension distance L2 between the far end of the ferrule and the far end of the outer tube is the extension distance of the ferrule along the longitudinal axis direction.

5. A snare according to claim 4, wherein:

the ratio of the diameter L1 of the loop of the snare to the extension distance L2 of the loop along the longitudinal axis direction is 1: 4-1: 1.5, wherein the diameter L1 of the loop of the snare is the maximum distance between the two axially symmetrical sides of the loop, and the extension distance L2 of the loop along the longitudinal axis direction is the distance between the farthest end of the loop and the farthest end of the outer tube.

6. A snare according to claim 5, wherein the ratio of L1 to L2 is 1:3 to 1:2.34, and L1 has a value in the range of 10mm to 40 mm.

7. A snare according to claim 1, wherein:

the two side flat wire structures with the axially symmetrical ferrule are respectively provided with at least an arc-shaped section flat wire structure and a straight line section flat wire structure, and the reinforced bending part is located at the transition position of the arc-shaped section flat wire structure to the straight line section flat wire structure.

8. A snare according to any one of claims 1 to 7, wherein:

the ratio of the section thickness P to the height Q of the ferrule flat wire structure is 1: 3-1: 2.

9. A snare according to any one of claims 1 to 7, wherein: the section of the flat wire structure is rectangular or sector-shaped with an opening facing the longitudinal axis direction of the ferrule.

10. A snare according to any one of claims 1 to 7, wherein: the ferrule is provided with scales.

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