Abstract: An expandable structure comprising: a first shape memory (SM) portion which is in a strain-induced state; and a second portion which resists expansion of said structure due to said first portion, over a plurality of different expansion states of said first portion. Optionally, wherein said SM portion resists contraction of said structure due to forces applied by said second portion. Optionally or alternatively, said strain induced state is characterized by a SM portion expanding force decreasing as a function of strain of said SM portion, so as to have a difference of at least 10% in force between two strain states said structure is usable at.

Abstract: An expandable structure comprising: a first shape memory (SM) portion which is in a strain-induced state; and a second portion which resists expansion of said structure due to said first portion, over a plurality of different expansion states of said first portion. Optionally, wherein said SM portion resists contraction of said structure due to forces applied by said second portion. Optionally or alternatively, said strain induced state is characterized by a SM portion expanding force decreasing as a function of strain of said SM portion, so as to have a difference of at least 10% in force between two strain states said structure is usable at.

Abstract: A method of treatment of nasal conditions comprising: delivering an expandable structure in a crimped configuration to a nasal lumen; expanding the expandable structure within the nasal lumen to a stable expanded configuration; removing the structure from the nasal lumen, after a time period, where removing comprises causing the structure to self-crimp. The expandable structure optionally comprises: a first shape memory (SM) portion which is in a strain-induced state; and a second portion which resists expansion of said structure due to said first portion, over a plurality of different expansion states of said first portion. Optionally, the properties of the second portion vary over its cross section. For example an outer surface and/or peripheral layer may have desirable environmental resistance properties and/or a frame may have desirable mechanical properties, for example a high creep resistance.