RADIALLY EXPANDABLE NICKEL-TITANIUM SURGICAL STENT

摘要

A radially expandable surgical stent (10) is provided formed from a shape memory and/or superelastic material such as a nickel-titanium alloy. The stent (10) includes a series of wave-like struts (20) spaced apart by gaps (60). Each gap (60) is spanned by tie bars (70) at a maximum (64) width portion of the gap (60) or by an angled link (80) or a straight link (90) at a minimum (62) width portion of a gap (60). Hence, axial expansion or contraction of the stent (10) is avoided when the stent (10) is radially expanded or contracted. Each strut (20) is formed from a series of substantially linear legs (30) joined together by free bends (40) or attachment bends (50). The legs (30) and bends (40, 50) can be provided with an enhanced thickness (36) to augment resistance of the stent (10) to fracture when radially expanded or contracted. The stent (10) can be radially contracted to a diameter less than one-fourth of its radially expanded configuration when in a martensite phase. The stent (10) returns to a shape memory austenite phase when the stent (10) is unloaded or loaded below its yield strength and has a temperature above its transition temperature. The stent (10) can thus be easily collapsed and implanted within a body lumen for later radial expansion to support the body lumen.