Expandable slide and lock stent

1. An expandable slide and lock polymer stent, the stent comprising:

first and second helical backbones each comprising a plurality of slots, each slot having an axis extending in a circumferential direction, the first and second helical backbones extending in a helical path along an axis of the stent;

a first set of elongate members defining proximal and distal ends, the proximal ends of the first set of elongate members being coupled to the first helical backbone with the first set of elongate members extending in a circumferential direction from the first helical backbone through the slots of the second helical backbone, the first set of elongate members being axially offset from each other;

a first crossbar coupling the distal ends of the first set of elongate members;

a second set of elongate members defining proximal and distal ends, the proximal ends of the second set of elongate members being coupled to the second helical backbone and extending in a circumferential direction from the second helical backbone through the slots of the first helical backbone, the second set of elongate members being axially offset from each other and from the first set of elongate members; and

a second crossbar coupling the distal ends of the second set of elongate members;

wherein the first and second helical backbones and the first and second sets of elongate members and the first and second crossbars form first and second radial elements that can be interconnected to collectively form a tubular member having a circumference which is expandable between a collapsed diameter and an expanded diameter, the first and second radial elements configured to provide one-way expansion from the collapsed diameter to the expanded diameter.

2. A stent as in claim 1 , wherein the first crossbar has a recessed portion and the second crossbar has a recessed portion, the recessed portion of the first crossbar configured such that one of the elongate members of the second set can be at least partially disposed in the recessed portion of the first crossbar, the recessed portion of the second crossbar being configured to at least partially receive one of the elongate members of the first set therein.

3. A stent as in claim 2 , wherein the recessed portions of the first and second crossbars are recessed radially inwardly relative to the respective ones of the elongate members of the second and first sets.

4. A stent as in claim 2 , wherein the recessed portions of the first and second crossbars are recessed radially outwardly relative to the respective ones of the elongate members of the second and first sets.

5. A stent as in claim 1 , wherein the first set of elongate members is monolithically formed with the first helical backbone such that the coupling of the first crossbar to the distal ends of the first set of elongate members forms a tail-bond.

6. A stent as in claim 1 , wherein the second set of elongate members is monolithically formed with the second helical backbone such that the coupling of the second crossbar to the distal ends of the second set of elongate members forms a tail-bond.

7. A stent as in claim 1 , wherein the first crossbar is monolithically formed with the first set of elongate members.

8. A stent as in claim 1 , wherein the second crossbar is monolithically formed with the second set of elongate members.

9. A stent as in claim 1 , wherein the first set of elongate members are formed separately from the first helical backbone such that the coupling of the first set of elongate members with the first helical backbone forms one of a core-bond and a mid-rail bond.

10. A stent as in claim 9 , wherein the second set of elongate members are formed separately from the second helical backbone such that the coupling of the second set of elongate members with the second helical backbone forms one of a core-bond and a mid-rail bond.

11. A stent as in claim 1 , wherein the elongate members comprise one or more teeth for engaging respective slots to provide one-way expansion of the stent.

12. A stent as in claim 11 , wherein each slot comprises a central passage and at least one internal recess for engaging the teeth of the elongate member.

13. A method for forming the stent of claim 12 , comprising forming the central passage as a first through hole in the backbone in a circumferential direction of stent, and forming the at least one internal recess as a second through hole in the backbone in a direction transverse to the circumferential direction of the central passage such that the first and second through holes partially overlap.

14. An expandable stent, comprising a plurality of radial elements interconnected to form a tubular member, each radial element comprising a helical support member comprising a plurality of slots and a plurality of circumferential rails, wherein a first radial element is interconnected with a second radial element, such that the circumferential rails of the first radial element are received into the slots of the helical support member of the second radial element, wherein the expandable stent is made from a bioresorbable polymer and exhibits structural properties equivalent to a metal stent.

15. A radial element for forming an expandable slide and lock polymer stent, the radial element comprising:

a continuously-slotted helical backbone member having a plurality of engagement slots and a plurality of connection slots, at least one engagement slot being spaced between consecutive connection slots along the backbone, each helical backbone member generally defining a longitudinal axis;

a plurality of elongate rib elements having proximal and distal portions, the proximal portion being interconnectable with one or more connections slots of the continuously slotted backbone member, each rib element being positionable generally circumferentially about the longitudinal axis and having a fixed engagement at a non-perpendicular angle with respect to the helical backbone member;

wherein the plurality of elongate rib elements is arranged to interconnect with at least one other helical backbone member of another radial element so as to form an expandable tubular skeleton, the elongate rib elements having a one-way slidable engagement with the engagement slots of the helical backbone member of the other radial element, the tubular skeleton being configured to expand radially between a collapsed diameter and an expanded diameter upon circumferential motion of the slidable engagement of the rib elements to the helical backbone members; and

wherein the slidable engagement includes a mechanism restraining collapse of the tubular skeleton from the expanded diameter towards the collapsed diameter.

16. A radial element as in claim 15 , wherein the helical backbone comprises portions of reduced thickness for allowing at least partial nesting of an elongate rib element thereagainst.

17. A radial element as in claim 15 , wherein a pair of elongate rib elements are interconnected at their distal portions by a crossbar.

18. A radial element as in claim 17 , wherein the crossbar comprises an offset portion configured to at least partially receive an elongate rib of an adjacent radial element for reducing a passing profile of a stent formed using a plurality of radial elements.

19. A radial element as in claim 15 , wherein the helical backbone extends helically at a generally fixed radius and helix angle relative to the longitudinal axis.

20. A radial element as in claim 19 , wherein the engagement slot comprises a through slot that defines a central axis extending in a generally circumferential direction and within a plane that is perpendicular to the longitudinal axis of the radial element, the central axis of the engagement slot extending at a non-perpendicular angle relative to the helical backbone.