| 摘要 |
A stent adapted for placing in the urethra so as to retain the urethra's diameter above a critical level is provided. The stent comprises: a spiral band made of a two-way shape memory alloy having two memory states consisting of a first state in which said alloy is soft and substantially deformable and a second state in which the alloy has super elastic properties and is substantially non-deformable, the alloy changes from the fast state to the second state at a first transition temperature being above physiological body temperature and changes from the second to the first state at a second transition temperature being below physiological body temperature; in the second state consecutive windings of the band are adjacent one another so that they form together essentially a continuous cylindrical tube of a diameter above said critical level; in the first state the band forms a coiled structure having a maximal external diameter such so as to allow deployment of stent within the urethra. |
