Endoscopic extraction devices, wire basket stone extractors, stent retrievers, snares and method of constructing the same

• US 5,330,482 A
• Filed: 09/27/1993
• Issued: 07/19/1994
• Est. Priority Date: 06/17/1991
• Status: Expired due to Term

• Current Assignee: Cook Medical Incorporated (Cook Group Incorporated)
• Original Assignee: Wilson-Cook Medical Incorporated (Cook Group Incorporated)
• Inventors: Gibbs, Rebecca C., Fremund, Zdenek A., Martel, Mark C.
• Primary Examiner(s): Thaler, Michael H.
• Application Number:
  US08/127,446
• Time in Patent Office: 295 Days
• Field of Search: 606/78, 606/106, 606/113, 606/127, 606/128, 606/108, 228/262.31, 428/960, 428/660, 428/680, 428/685, 428/679
• 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 2017/2212 having a closed distal end, e.g. a loop
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2210/0019 operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation
• CPC Class Codes: D07B 1/0693 having a strand configuration
• CPC Class Codes: D07B 2201/2006 characterised by a value or range of the dimension given
• CPC Class Codes: D07B 2201/2023 with core
• CPC Class Codes: D07B 2201/2029 Open winding
• CPC Class Codes: D07B 2201/2051 characterised by a value or range of the dimension given
• CPC Class Codes: D07B 2201/2059 comprising wires
• CPC Class Codes: D07B 2201/2066 characterised by the materials used
• CPC Class Codes: D07B 2201/2067 characterised by the elongation or tension behaviour
• CPC Class Codes: D07B 2205/3085 Alloys, i.e. non ferrous
• CPC Class Codes: D07B 2801/12 Strand
• CPC Class Codes: D07B 2801/14 Core
• CPC Class Codes: D07B 5/00 Making ropes or cables from special materials or of particular form
• CPC Class Codes: Y10T 428/12806 Refractory [Group IVB, VB, or VIB] metal-base component
• CPC Class Codes: Y10T 428/12979 Containing more than 10% nonferrous elements [e.g., high alloy, stainless]

Abstract

Disclosed herein is an endoscopic extraction device which retains its operative usefulness for longer periods of time, and therefore need to be replaced less frequently. This extended instrument life is accomplished through the use of a composite wire construction, which includes, an inner monofilament wire of nitinol material surrounded by six stranded stainless steel wires. A wire construction in which a nitinol wire is surrounded by five stranded stainless steel wires is also disclosed. After constructing a wire basket in the normal manner using this material, heat is applied to the formed basket in its pre-formed shape to set the memory characteristics of the inner nitinol core.

Claims

1. In a medical extraction device, said device including a retaining cannula and an extraction assembly including at least one extraction wire extendable from said retaining cannula into a pre-formed configuration for removing a foreign body from within a patient, the improvement comprising said extraction wire being constructed out of a composite construction which includes an inner monofilament wire of shape memory material surrounded by a plurality of at least five outer stranded wires stranded together about said inner monofilament wire of shape memory material, said outer stranded wires being made of material which is readily solderable as compared to said shape memory material, and

wherein said extraction wire is attached to the rest of said extraction assembly by the soldering of said outer stranded wires to each other and to the rest of said extraction assembly.

2. The improvement in a medical extraction device according to claim 1 in which said stranded wires are made of stainless steel.

3. The improvement in a medical extraction device according to claim 2 in which said stranded stainless steel wires includes five wires.

4. The improvement in a medical extraction device according to claim 2 in which said stranded stainless steel wires includes six wires.

5. The improvement in a medical extraction device according to claim 1 in which said shape memory material is nitinol.

6. The improvement in a medical extraction device according to claim 4 in which said shape memory material is nitinol.

7. The improvement in a medical extraction device according to claim 5 in which said shape memory material is nitinol.

8. The improvement in a medical extraction device according to claim 6 in which said inner wire has a diameter of about 0.005" and said surrounding wires each have a diameter of about 0.0055".

9. The improvement in a medical extraction device according to claim 7 in which said inner wire has a diameter of about 0.005" and said surrounding wires each have a diameter of about 0.0004".

10. An improvement in the method for constructing a medical extraction device, said medical extraction device including a retaining cannula, and an extraction assembly including at least one extraction wire extendable from said retaining cannula into a pre-formed configuration for removing a foreign body from within a patient, the improvement comprising the steps of:

constructing said extraction wire out of a composite construction which includes an inner monofilament wire of shape memory material surrounded by a plurality of at least five outer stranded wires stranded together about said inner monofilament wire of shape memory material, said outer stranded wires being made from a material which is readily solderable as compared to said shape memory material;

joining said extraction wire to the rest of said extraction assembly by soldering said stranded wires to each other and to the rest of said extraction assembly;

forming said extraction wire into a desired configuration for use in said medical extraction device; and

applying heat to said formed extraction wire to set the shape memory characteristics of said inner monofilament wire of shape memory material.

11. The improvement in the method for constructing a medical extraction device according to claim 10 in which said stranded wires are made of stainless steel.

12. The improvement in the method for constructing a medical extraction device according to claim 10 in which said shape memory material is nitinol.

13. The improvement in the method for constructing a medical extraction device according to claim 11 in which said stranded stainless steel wires includes five wires.

14. The improvement in the method for constructing a medical extraction device according to claim 11 in which said stranded stainless steel wires includes six wires.

15. The improvement in the method for constructing a medical extraction device according to claim 13 in which said shape memory material is nitinol.

16. The improvement in the method for constructing a medical extraction device according to claim 14 in which said shape memory material is nitinol.

17. The improvement in the method for constructing a medical extraction device according to claim 15 in which said inner wire has a diameter of about 0.005" and said surrounding wires each have a diameter of about 0.0055".

18. The improvement in the method for constructing a medical extraction device according to claim 16 in which said inner wire has a diameter of about 0.005" and said surrounding wires each have a diameter of about 0.0004".

19. An improvement in the method for constructing a medical extraction device, said medical extraction device including a retaining cannula and an extraction assembly including a plurality of extraction wires extendable from said retaining cannula into a pre-formed configuration for removing a foreign body from within a patient, the improvement comprising the steps of:

constructing a plurality of extraction wires of approximately equal length out of a composite construction which includes an inner monofiliment wire of shape memory material surrounded by a plurality of at least five outer stranded wires stranded together about said inner monofilament wire of shape memory material, said outer stranded wires being made of material which is readily solderable as compared to said shape memory material;

joining the ends of said extraction wires by soldering said outer standard wires together at said ends;

joining said extraction wires at a set position a set distance from the distal end of said extraction wires by soldering said outer stranded wires together at said set position;

forming said extraction wires in the area between said set position and the distal end of said extraction wires into a desired configuration for use in said medical extraction device; and

applying heat to said formed extraction wires to set the shape memory characteristics of said inner monofilament wire of shape memory material.

20. The improvement in the method for constructing a medical extraction device according to claim 19 in which said stranded wires are made of stainless steel.

21. The improvement in the method for constructing a medical extraction device according to claim 20 in which said stranded stainless steel wires includes five wires.

22. The improvement in the method for constructing a medical extraction device according to claim 20 in which said stranded stainless steel wires includes six wires.

23. The improvement in the method for constructing a medical extraction device according to claim 19 in which said shape memory material is nitinol.