| 摘要 |
A minimally invasive medical retrieval device (10) useful for the removal of objects such as stones, calculi, concretions, foreign bodies and the like from the urinary, biliary, vascular or other systems includes a sheath (12) containing at least three wires (14) adjacently disposed in the sheath (12). At least one of the wires (14), and preferably all of them, can be moved longitudinally with respect to the sheath (12). The wires (14) have distal portions (16) which are formed so as to allow the engaging and removal of the object or objects. The distal portions (16) of the wires (14) preferably form a helical basket (22 or 40) particularly adapted for engaging urinary stones, calculi and concretions. Other grasping and manipulating shapes are useful as well. The wires (14) are substantially wedge-shaped in cross-section and substantially fill the entire cross-sectional area of the interior (26) of the sheath (12). The wedge-shaped wires (14) can be partly contained within a stainless steel cannula (28) positioned in the sheath (12). The sheath (12) can be of very small diameter, significantly smaller than the diameters of existing retrieval or extraction devices, preferably from about 0.5 to about 6.0 French. Unexpectedly, despite these small diameters, the baskets, graspers and the like into which the wedge-shaped wires (14) are formed simultaneously exhibit good resistance to twisting and bending, while being capable of being formed into shapes (such as helical baskets) not normally achieved with flat wires.
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