Tracheal stent

Abstract

Tracheal stents may include a plurality of wave form structures each extending radially about the support structure, a plurality of axial loop members extending axially between adjacent wave form structures and a polymeric covering disposed thereover. Tracheal stents may include an expandable metal structure and a plurality of spacer fins extending above an outer surface of the expandable metal structure. The plurality of spacer fins may be formed of a material different than that of the expandable metal structure.

What is claimed is: 
     
         1 . A medical stent extending from a first end to a second end, the medical stent comprising:
 a support structure extending from the first end to the second end, the support structure including a plurality of wave form structures each extending circumferentially about the support structure and a plurality of axial loop members extending axially between adjacent wave form structures; and   a polymeric covering disposed over the support structure;   wherein at least some of the plurality of axial loop members are configured to include an extended configuration in which the at least some of the plurality of axial loop members extend radially outward from an outer surface defined by the plurality of wave form structures.   
     
     
         2 . The medical stent of  claim 1 , wherein at least some of the wave form structures extend circumferentially about 360 degrees about the support structure and form closed rings. 
     
     
         3 . The medical stent of  claim 1 , wherein at least some of the wave form structures comprise a nickel-titanium alloy. 
     
     
         4 . The medical stent of  claim 1 , wherein at least some of the wave form structures are formed from nitinol wire. 
     
     
         5 . The medical stent of  claim 4 , wherein at least some of the wave structures are defined by a wire diameter that is in the range of about 0.2 to about 0.5 millimeters. 
     
     
         6 . The medical stent of  claim 1 , wherein at least some of the wave form structures are defined by a wave frequency in the range of about 0.5 to about 4 waves per centimeter and a wave amplitude in the range of about 0.25 to about 1 centimeters. 
     
     
         7 . The medical stent of  claim 1 , wherein at least some of the plurality of axial loop members extend from a peak, a valley or a transition region of a wave form structure of the plurality of wave form structures to a peak, a valley or a transition region of an adjacent wave form structure of the plurality of wave form structures. 
     
     
         8 . The medical stent of  claim 1 , wherein the plurality of axial loop members provide the only direct connection between adjacent wave form structures of the plurality of wave form structures. 
     
     
         9 . A method of forming a support structure for an endoprosthesis having a first end, a second end and a lumen extending therebetween, the method comprising:
 forming a first wave form structure from a first wire, the first wave form structure undulating side to side while extending circumferentially around to form a first closed ring;   forming a second wave form structure from a second wire, the second wave form structure undulating side to side while extending circumferentially around to form a second closed ring; and   securing an axial loop member having a first end and a second end, the first end secured to the first wave form structure and the second end secured to the second wave form structure.   
     
     
         10 . The method of  claim 9 , wherein the first wave form structure and the second wave form are formed on a mandrel. 
     
     
         11 . The method of  claim 9 , further comprising forming a plurality of additional wave form structures from a plurality of wires, each of the plurality of additional wave form structures undulating side to side while extending circumferentially around to form a plurality of additional closed rings. 
     
     
         12 . The method of  claim 11 , further comprising securing a plurality of axial loop members between adjacent wave form structures of the plurality of additional wave form structures. 
     
     
         13 . The method of  claim 9 , wherein the first wire and the second wire comprise a nitinol wire. 
     
     
         14 . The method of  claim 9 , wherein the first end of the axial loop member is secured to the first wave form structure via welding. 
     
     
         15 . A medical stent extending from a first end to a second end, the medical stent comprising:
 an expandable metal structure extending from the first end to the second end, the expandable metal structure convertible between a compressed configuration for delivery and an expanded configuration once deployed, the expandable metal structure including an inner surface defining a stent lumen and an outer surface; and   a plurality of spacer fins extending above the outer surface of the expandable metal structure;   wherein the plurality of spacer fins are formed of a material different than that of the expandable metal structure.   
     
     
         16 . The medical stent of  claim 15 , wherein the plurality of spacer fins are formed of a biodegradable or bioabsorbable material. 
     
     
         17 . The medical stent of  claim 15 , wherein the plurality of spacer fins are formed from a filament that is interlaced within the expandable metal structure. 
     
     
         18 . The medical stent of  claim 15 , wherein the plurality of spacer fins are separately formed each having an end, and the ends of the plurality of spacer fins are encapsulated in a polymeric coating that is disposed over the expandable metal structure. 
     
     
         19 . The medical stent of  claim 15 , wherein the plurality of spacer fins comprise a cap secured to high spots formed within the expandable metal structure. 
     
     
         20 . The medical stent of  claim 15 , wherein at least some of the plurality of spacer fins are triangular in shape, with a base secured relative to the expandable metal structure and an apex extending above the base.