RETRIEVAL DEVICE MADE OF PRECURSOR ALLOY CABLE
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Abstract
A medical retrieval device for retrieving foreign objects from a patient and the method of constructing the device are disclosed. The device incorporates a wire cable composed of a precursor alloy to a superelastic material to improve durability of the device. Because precursor alloys exhibit, a linear stress-strain relationship and a yield point associated with a relatively high stress level, the device transfers greater stresses before experiencing deformation. Thus, greater crushing forces can be achieved using a device of this type. These crushing forces may be needed when the foreign object is too large to remove intact. This property also facilitates the device in dilating ducts to retrieve foreign objects. Using the precursor alloy additionally eliminates the need for heat treatment of the cables used in constructing the device. A retrieval device made of precursor alloy cable also is less susceptible to permanent deformation and unwinding during use.
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Citations
15 Claims
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1. (canceled)
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2. A medical device comprising:
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a coupling tube having a proximal end and a distal end; a nosepiece; and a plurality of cables having a first end and a second end, wherein said first end of each cable is fixedly attached to the nosepiece and the second end is operably coupled to the coupling tube, wherein each of the plurality of cables further comprises a plurality of wire strands at least one strand of which comprises a precursor to a superelastic alloy, said alloy having the property of having a substantially linear stress-strain curve in such that the strain increases in a reversible manner as stress increases up to a plastic yield at which stress permanent plastic deformation occurs; wherein each of the plurality of cables has a first configuration in which the cable is collapsed into a narrow space and a second configuration in which the cable is expanded such that the plurality of cables form a basket. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification