Apparatus for entrapping and extracting objects from body cavities

• US 8,469,970 B2
• Filed: 07/11/2011
• Issued: 06/25/2013
• Est. Priority Date: 07/11/2011
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Great Aspirations Ltd. (Nordson Corporation)
• Inventors: Diamant, Valery, Lotan, Chaim, Danenberg, Haim
• Primary Examiner(s): Severson, Ryan
• Assistant Examiner(s): MILES, JONATHAN WADE
• Application Number:
  US13/179,750
• Publication Number:
  US 20130018387A1
• Time in Patent Office: 715 Days
• Field of Search: 606/110, 606/111, 606/112, 606/113, 606/114, 606/115, 606/127, 606/128, 606/200
• US Class Current: 606/127
• 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 2017/00862 elastic or resilient
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61B 2017/00871 polymeric
• CPC Class Codes: A61B 2017/22039 eccentric
• CPC Class Codes: A61B 2017/2215 having an open distal end

Abstract

A retrieval apparatus for entrapping and retaining an object located in a body for its extraction therefrom is described. The retrieval apparatus includes a snare and a snare control assembly. The snare has a proximal section and a distal section, and comprises a plurality of filaments extending from a proximal end of the proximal section towards the distal section, and then returning to the proximal end to form a plurality of loops. In the deployed state, the loops are interlaced to each other within the proximal section and are free and not interleaved within the distal section. Segments of the filaments of the distal section are bent with respect to segments of the filaments of the proximal section such that the retrieval snare in the contracted state forms a hollow cavity extending from the distal section towards the proximal section.

Claims

1. A retrieval apparatus for entrapping and retaining an object located in a body for its extraction therefrom, the apparatus comprising a retrieval snare formed by a plurality of filaments defining proximal and distal sections interconnected to each other;

the snare being changeable between its deployed state and contracted state;

wherein the filaments extend from a proximal end of the proximal section towards the distal section, and then return to the proximal end to form a plurality of loops, the loops are interlaced with each other only within the proximal section, while being free within the distal section in the deployed state, distal ends of the loops approach each other when the snare is in the contracted state;

wherein the filament loops are flat and planar along at least a portion of their length; and

wherein sides of at least a part of the filament loops are bent within the distal section and arcuate into arcs at a distal end of the distal section such that said retrieval snare in the contracted state forms a hollow cavity at least at the distal section, wherein the filaments forming sides of the loops are bent three times to define four straight wire segments angled with respect to each other at a sequence of three angles having predetermined values.

2. The retrieval apparatus of claim 1, further comprising a snare control assembly comprising:

a delivery catheter having at least one lumen, and configured to penetrate into the body for reaching the object; and

a manipulation member coupled to the snare, and configured to path within said at least one lumen of the delivery catheter, and to operate for (i) protracting the snare from the delivery catheter for opening the snare and (ii) retracting the snare within the delivery catheter for collapsing the retrieval snare inside of the delivery catheter.

3. The retrieval apparatus of claim 2, wherein the snare further includes a mesh formed by interweaved and/or overlapping wires weaved around a snare carcass structure formed by said plurality of filaments.

4. The retrieval apparatus of claim 2, wherein the snare further includes a cover film configured for coating a snare carcass structure formed by the filaments.

5. The retrieval apparatus of claim 4, wherein the manipulation member includes an aspiration tube coupled to the filament loops at the proximal end of the snare along an external surface circumference of the aspiration tube.

6. The retrieval apparatus of claim 5, wherein the manipulation member includes an aspiration lumen and a guide wire lumen, both lumens extending between the proximal and distal ends of the manipulation member.

7. The retrieval apparatus of claim 6, wherein the wire guide lumen is arranged within the aspiration lumen and separated from the aspiration lumen by a separation wall.

8. The retrieval apparatus of claim 6, further comprising a guiding catheter including a lumen configured for housing the delivery catheter, a guide wire extending within the guide wire lumen;

and a suction device coupled to the aspiration lumen at the proximal end of the manipulation member.

9. The retrieval apparatus of claim 5, wherein the delivery catheter includes a snare lumen and a guide wire lumen, both lumens extending between the proximal and distal ends of the delivery catheter.

10. The retrieval apparatus of claim 9, further comprising a guiding catheter including a lumen configured for housing the delivery catheter, a guide wire extending within the guide wire lumen;

and a suction device coupled to the aspiration lumen at the proximal end of the delivery catheter.

11. The retrieval apparatus of claim 5 configured for withdrawing thromboembolic material.

12. The retrieval apparatus of claim 4, wherein the cover film has radiopaque properties.

13. The retrieval apparatus of claim 2, wherein the manipulation member includes at least a part of the plurality of filaments extending from the snare proximal end.

14. The retrieval apparatus of claim 2, wherein the manipulation member includes a pushing tube containing at least a part of the plurality of filaments axially disposed within a lumen of the pushing tube along at least a portion of the tube'"'"'s length.

15. The retrieval apparatus of claim 1, wherein said predetermined values of said sequence of three angles counted from the snare proximal end are in the range of 160-175 degrees, 125-165 degrees, and 95-170 degrees, respectively.

16. The retrieval apparatus of claim 1, wherein an opening angle of the loops in a fully deployed state is in the range of about 60 degrees to about 130 degrees.

17. The retrieval apparatus of claim 16, wherein the angle (δ

) between the first and second straight wire segments (L₁ and L₂) deviates from the opening angle (θ

) of the loops in the fully deployed state by 30 to 115 degrees.

18. The retrieval apparatus of claim 1, wherein the angle (ε

) between the second and third straight wire segments (L₂ and L₃) deviates from the angle (δ

) between the first and second straight wire segments (L₁ and L₂) by 0 to 50 degrees.

19. The retrieval apparatus of claim 1, wherein a relationship between said predetermined values of said sequence of three angles is such that a direction of the third segment counted from the snare proximal end is coaxial with the direction of the delivery catheter.

20. The retrieval apparatus of claim 1, wherein a length of the first segment counted from the snare proximal end is greater than the length of the second segment by two to six times.

21. The retrieval apparatus of claim 1, wherein a length of the second segment counted from the snare proximal end is equal to or longer than the length of the third segment by up to two times.

22. The retrieval apparatus of claim 1, wherein at least one loop has a side that is permanently connected along the proximal portion to an opposite side of an adjacent loop at more than one connection point.

23. The retrieval apparatus of claim 22, wherein the permanent connection is carried out by twisting each pair of the filaments.

24. The retrieval apparatus of claim 1, wherein each side of each loop is permanently connected to a side of an adjacent loop near the proximal end along a predetermined segment length.

25. The retrieval apparatus of claim 1, wherein the loops are permanently interconnected to each other at least at one additional joint point selected within the proximal section in places where one loop crosses another loop.

26. The retrieval apparatus of claim 1, wherein a part of the filament loops is made of a thicker wire than the wire of the remaining loops.

27. The retrieval apparatus of claim 1, wherein at least a part of the filament loops have dimensions and shapes different from the dimensions and shapes of the other loops.

28. The retrieval apparatus of claim 1, wherein the snare further includes a closing element arranged at a distal section and configured for binding the loops together at their distal ends.

29. The retrieval apparatus of claim 1 wherein the filaments are made of metallic material.

30. The retrieval apparatus of claim 29, wherein the metallic material has thermo-mechanical shape memory and supereleastic characteristics.

31. The retrieval apparatus of claim 29, wherein the metallic material is one of NiTi based alloy and stainless steel.

32. The retrieval apparatus of claim 29, wherein the metallic material includes a radiopaque material.

33. The retrieval apparatus of claim 32, wherein the radiopaque material is at least one of the following metals:

Pt, Au, Ag, Pd, Ta, W, Nb, Co, and Cu.

34. The retrieval apparatus of claim 1, wherein the filaments are made of non-metallic material.

35. The retrieval apparatus of claim 34, wherein the non-metallic material comprises one of Capron and Nylon.

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

37. The retrieval apparatus of claim 1, wherein the filaments are covered by a coating layer.

38. The retrieval apparatus of claim 37, wherein said coating layer is made of a radiopaque material.

39. The retrieval apparatus of claim 1, wherein parts of the filaments are covered by radiopaque coils.

40. The retrieval apparatus of claim 1, comprising at least one radiopaque, marker attached to at least one loop in said distal portion.

41. The retrieval apparatus of claim 40, wherein the radiopaque marker is a ferrule placed around the filament.

42. The retrieval apparatus of claim 1 wherein the filaments are multiwire strands.

43. The retrieval apparatus of claim 42 wherein said multiwire strands include a central core wire and at least one other wire twisted about said central core wire.

44. The retrieval apparatus of claim 43, wherein said other wire is made of a material having a level of radiopacity greater than the level of radiopacity of said central core wire.

45. A retrieval apparatus for entrapping and retaining an object located in a body for its extraction therefrom, the apparatus comprising a retrieval snare formed by a plurality of filaments defining proximal and distal sections interconnected to each other;

the snare being changeable between its deployed state and contracted state;

wherein the filaments extend from a proximal end of the proximal section towards the distal section, and then return to the proximal end to form a plurality of loops, the loops are interlaced with each other only within the proximal section, while being free within the distal section in the deployed state, distal ends of the loops approach each other when the snare is in the contracted state;

wherein the filament loops are flat and planar along at least a portion of their length; and

wherein sides of at least a part of the filament loops are bent within the distal section and arcuate into arcs at a distal end of the distal section such that said retrieval snare in the contracted state forms a hollow cavity at least at the distal section;

wherein an interlaced pattern of the proximal section is formed by interleaving each lateral side of the filament loops with three corresponding opposite sides of the three neighboring loops arranged in a series.