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

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.

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.