RETRIEVAL SNARE FOR EXTRACTING FOREIGN OBJECTS FROM BODY CAVITIES AND METHOD FOR MANUFACTURING THEREOF

• US 20080086149A1
• Filed: 10/02/2007
• Published: 04/10/2008
• Est. Priority Date: 10/06/2006
• Status: Active Grant

• Current Assignee: Cook Medical Technologies, LLC (Cook Group Incorporated), Nordson Corporation
• Original Assignee: Cook Incorporated (Cook Group Incorporated), Lithotech Medical Ltd. (Nordson Corporation)
• Inventors: Diamant, Valery, Yasko, Nadezka, Delaney, Kevin
• Granted Patent: US 9,271,746 B2
• Time in Patent Office: Days
• US Class Current: 606/113
• CPC Class Codes: A61B 17/221 Gripping devices in the form of loops or baskets for gripping calculi or similar types of obstructions surgical snare instruments A61B17/32056
• CPC Class Codes: A61B 2017/00526 Methods of manufacturing
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61B 2017/22035 for retrieving or repositioning foreign objects
• CPC Class Codes: A61B 2017/2215 having an open distal end
• CPC Class Codes: A61B 2090/3966 Radiopaque markers visible in an X-ray image
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: B21F 45/008 of medical instruments, e.g. stents, corneal rings medical science A61
• CPC Class Codes: Y10T 29/49874 Prestressing rod, filament or strand

Abstract

A retrieval snare for entrapping and retaining a foreign object located in a body and a method for manufacturing of the snare are provided. The snare comprises a structure having a proximal portion and a distal portion and includes a plurality of filaments. The filaments extend from an end of the proximal portion towards the distal portion and return to the end of the proximal portion to form a plurality of loops. The loops are not interconnected at the distal portion, but each side of each loop are connected to a side of an adjacent loop in the proximal portion at more than one point, thereby providing structural rigidity and dilatation ability to the snare.

Claims

1. A retrieval snare for entrapping and retaining a foreign object located in a body for its extraction therefrom, the snare comprising:

a structure having a proximal portion and a distal portion and including a plurality of filaments extending from an end of the proximal portion towards the distal portion and returning to the end to form a plurality of loops, each of the loops being free at the distal portion, each loop including a side connected along the proximal portion to a side of an adjacent loop at more than one connection point for structural rigidity and dilatation ability to the snare.

2. The retrieval snare of claim 1 wherein the sides of the loops along the proximal portion are connected by twisting each pair of the filaments forming the sides of the loops thereby creating twisted parts of the loops between the end and distal connection points.

3. The retrieval snare of claim 2 wherein the distal connection points of the adjacent loops are movable from the twisted parts of the loops toward the distal portion of the snare when the snare is retracted in a sheath thereby forming an intermediate portion between the proximal portion and the distal portion of the snare, the intermediate portion including convex cells formed between the distal connection points and the twisted parts of the loops where the corresponding pair of the filaments separate from each other.

4. The retrieval snare of claim 1 wherein the filaments are bound together at the end of the proximal portion to form a manipulation member.

5. The retrieval snare of claim 1 wherein the loops are selected from:

planar, bent into C-shaped configuration, and bent into S-shaped configuration.

6. The basket of claim 1 wherein the filaments are made of metallic material.

7. The retrieval snare of claim 6 wherein the metallic material has at least one of thermo-mechanical shape memory and superelastic characteristics.

8. The retrieval snare of claim 1 wherein the filaments are made of non-metallic material.

9. The retrieval snare of claim 6 wherein the metallic material includes a radiopaque material.

10. The retrieval snare of claim 1 wherein said filaments are made of a core tube containing an axially disposed radiopaque wire.

11. The retrieval snare of claim 1 wherein the filaments are covered by a coating layer, made of a radiopaque material.

12. The retrieval snare of claim 1 wherein parts of the filaments are covered by radiopaque coils.

13. The retrieval snare of claim 1 wherein the filaments are multiwire strands.

14. A retrieval snare apparatus for entrapping and retaining a foreign object located in a body for its extraction therefrom, the snare apparatus comprising:

a retrieval snare for entrapping and retaining a foreign object located in a body for its extraction therefrom, the snare comprising a structure having a proximal portion and a distal portion and including a plurality of filaments extending from an end of the proximal portion towards the distal portion and returning to the end to form a plurality of loops, each of the loops being free at the distal portion, each loop including a side connected along the proximal portion to a side of an adjacent loop at more than one connection point for structural rigidity and dilatation ability to the snare; and

a snare control assembly coupled to the snare structure, said snare control assembly comprising a sheath adapted to penetrate into the body for reaching the object, a manipulator for manipulating the snare for extraction of the object from the body, and a manipulation member arranged within the dilator sheath for connecting the snare to the manipulator, the snare control assembly being configured for retracting the snare within the sheath and protracting the snare therefrom for its opening.

15. The retrieval snare apparatus of claim 14 wherein the manipulation member includes at least a part of the plurality of filaments extending from said proximal end towards the manipulator.

16. The retrieval snare apparatus of claim 14 wherein the manipulation member includes a tube containing the part of the plurality of filaments axially disposed within a lumen of the tube along at least a portion of the length of the tube.

17. The retrieval snare apparatus of claim 14 wherein the part of the plurality of filaments extended from the end of the proximal portion towards the manipulator are cut off at a predetermined distance from the end, forming free ends of the plurality of filaments.

18. The retrieval snare apparatus of claim 17 wherein the manipulation member is made of a material including at least one of NiTi based alloy, stainless steel, and polymer.

19. A method for manufacturing a retrieval snare for entrapping and retaining a foreign object located in a body for its extraction therefrom, the method comprising:

selecting a predetermined number of filaments;

providing a weaving jig having a working surface, the working surface having a predetermined convex shape defining an opening angle of the snare and a predetermined pattern formed by radial channels configured on the surface, the working surface having a central portion and a peripheral portion, at least a part of the radial channels being formed in the form of a plurality of notches extending from a center of the surface towards the peripheral portion, the plurality of notches being not interconnected at the peripheral portion, and each radial channel includes at least one notch that shares a common part with at least one notch of an adjacent radial channel in the central portion of the working surface;

placing the filaments into the radial channels to form a plurality of filament loops with free parts of the filaments arranged in the center of the working surface;

fastening the filament loops to the jig at the peripheral portion of the working surface;

connecting each side of each filament loop disposed in the common part of the radial channels to a side of an adjacent filament loop at more than one point;

fastening the free parts of the filaments arranged in the center of the working surface together;

shape storing annealing the retrieval snare, thereby imparting structural rigidity and dilatation ability to the snare;

cooling the retrieval snare;

unfastening the parts of the filaments tied at least at the peripheral portion of the working surface;

removing the jig; and

binding the free parts of the filaments together.

20. The method of claim 19 wherein the sides of the filament loops disposed in the common part of the radial channels are connected by twisting each pair of the filaments forming the corresponding sides.

21. The method of claim 19 further including the step of forming a manipulation member.

22. The method of claim 21 wherein the forming of the manipulation member includes twisting the free parts of the filaments.

23. The method of claim 21 wherein the forming of the manipulation member includes:

providing a tube; and

cutting off a predetermined number of the free parts of the filaments and axially disposing the remaining filaments within a lumen of the tube along at least a portion of a length of the tube.

24. The method of claim 19 further comprising the step of attaching at least one radiopaque marker to at least one filament loop.

25. The method of claim 21 further comprising:

providing a sheath adapted to penetrate into the body for reaching the object;

providing a manipulator configured for manipulating the snare for extraction the object from the body,

arranging a manipulation member within the sheath; and

connecting the manipulation member to the manipulator.