Stent Device with Multiple Helix Construction
An improved stent design is disclosed that employs a series of helically oriented expansion elements encircling the stent. Each of the expansion elements includes a stepped pattern employing two distinct pitch angles. The expansion elements are oriented to cooperate with each other to form a series of virtual radially expandable rings that provide suitable outward force for proper stent function, but which are not connected together to form a continuous coherent ring if separated from the stent as a whole. In this manner, a distinctive stent design is provided that has numerous functional benefits over stents described in the prior art.
1 . A stent having a longitudinal axis comprising
multiple undulated elements arranged around the longitudinal axis, each undulating element including a first pitch angle oriented helically around the longitudinal axis and a second pitch angle oriented essentially perpendicular to the longitudinal axis;
wherein the undulating elements are oriented relative to each other so that their second pitch angles are aligned with one another within a radial expansion zone; and
wherein the undulating elements are not connected to one another within the radial expansion zone.
2 . The stent of claim 1 wherein each undulating element is connected to an adjacent undulating element.
3 . The stent of claim 1 wherein the stent includes
a series of radial expansion zones oriented essentially perpendicular to the longitudinal axis; and
within each radial expansion zone there are at least two separate undulating elements.
4 . The stent of claim 3 wherein within each radial expansion zone there are at least three separate undulating elements.
5 . The stent of claim 1 wherein when the radial expansion zone is separated from the stent as a whole, each of the undulating elements in the expansion zone will readily separate from one another.
6 . The stent of claim 1 wherein the undulating elements in the radial expansion zone are not independently radial expandable from each other.