ENDOPROSTHESIS STRUCTURES HAVING SUPPORTING FEATURES
An endoprosthesis includes a plurality of serpentine rings having supporting features which increase hoop strength, inhibit recoil, and provide an increased surface area. The supporting features may be formed between adjacent axial struts of the serpentine rings or may be positioned between axial lengths joining the serpentine rings together.
1 . An endoprosthesis comprising:
a plurality of circumferentially expandable serpentine rings, each serpentine ring including axial struts joined by crowns, wherein the crowns act as hinges allowing the struts to spread as the ring opens circumferentially;
axial links joining at least some crowns on adjacent rings; and
supporting features extending between at least some adjacent struts of at least some of the serpentine rings, wherein the supporting features elongate and the struts remain substantially undeformed as the rings circumferentially expand.
2 . An endoprosthesis as in claim 1 , at least partially comprising a biodegradable material.
3 . An endoprosthesis as in claim 1 , at least partially comprising a metal.
4 . An endoprosthesis as in claim 1 , wherein the serpentine rings are sufficiently elastic so that they can be constrained in a small cross-sectional area and released to assume a circumferentially expanded configuration.
5 . An endoprosthesis as in claim 1 , wherein the serpentine rings are sufficiently malleable so that they can be circumferentially expanded by applying a radially outward force from within the ring.
6 . An endoprosthesis as in claim 1 , wherein the supporting feature comprises a U-shaped connector.
7 . An endoprosthesis as in claim 1 , wherein the supporting feature comprises a V-shaped connector.
8 . An endoprosthesis as in claim 1 , wherein the supporting feature comprises an S-shaped connector.
9 . An endoprosthesis as in claim 1 , wherein the supporting feature comprises a spiral-shaped connector.
10 . An endoprosthesis as in claim 9 , wherein the spiral-shaped connector has a ring core.
11 . An endoprosthesis as in claim 9 , wherein the spiral-shaped connector has a disk core.
12 . An endoprosthesis as in claim 1 , wherein the supporting feature comprises a W-shaped connector.
13 . An endoprosthesis as in claim 1 , wherein the supporting feature comprises an N-shaped connector.
14 . An endoprosthesis as in claim 1 , further comprising at least one additional supporting feature extending between at least some of the adjacent struts.
15 . An endoprosthesis as in claim 1 , wherein the supporting features extend between midpoints on the adjacent struts.
16 . An endoprosthesis as in claim 1 , wherein the supporting features extend between points near the crowns on the adjacent struts.
17 . An endoprosthesis as in claim 1 , wherein said supporting features extend between two points on adjacent axial struts and one point on the crown which joins the struts.
18 . An endoprosthesis as in claim 1 , wherein said supporting features have a cross-sectional area which is less than the cross-sectional area of the axial struts.
19 . An endoprosthesis as in claim 1 , wherein at least some of the supporting features have deflection points which preferentially yield when the serpentine rings is circumferentially expanded.
20 . An endoprosthesis as in claim 19 , wherein the deflection points comprise notches.
21 . An endoprosthesis as in claim 1 , wherein the axial links comprise linear beams.
22 . An endoprosthesis as in claim 21 , wherein the linear beams are aligned axially.
23 . An endoprosthesis as in claim 21 , wherein the linear beams are aligned at an angle relative to the axis.
24 . An endoprosthesis comprising:
a plurality of circumferentially expandable serpentine rings, each serpentine ring including axial struts joined by crowns, wherein the crowns act as hinges allowing the struts to spread as the ring opens circumferentially;
axial links joining at least some crowns on adjacent rings; and
supporting features extending between at least some adjacent axial links between adjacent serpentine rings, wherein the supporting features elongate as the rings circumferentially expand.
25 . An endoprosthesis as in claim 24 , wherein the supporting feature comprises a serpentine connector.
26 . An endoprosthesis as in claim 24 , wherein the supporting feature comprises a box connector.