DILATATION DEVICE

A dilatation device 10 includes a support 14 and at least one inflatable tube 16. The inflatable tube is wound helically around the support and also defines a series of inflatable zones 26 along its length, with successive inflatable zones spaced by an intermediate zone 28 that is more resistive to radial expansion than the inflatable zones. The inflatable tube further defines a fluid inlet 22, 24 for: introducing fluid to inflate the inflatable zones; and extracting fluid from the inflatable tube to deflate it, with each inflatable zone being in fluid communication with its successive inflatable zones via the intermediate zones. The axial critical buckling load of the inflatable zones is less than the radial critical buckling load of the inflatable zones, to cause the inflatable zones to concertina axially when the inflatable tube is depressurized, thereby causing the intermediate zones to displace towards each other.