Apparatus comprising a tube sized to receive visualization apparatus a deformable helical thread disposed on the exterior surface of the tube, the deformable helical thread (i) being transformable between a first configuration wherein the deformable helical thread comprises a reduced profile and/or a reduced rigidity and a second configuration wherein the deformable helical thread comprises an expanded profile and/or an increased rigidity, and (ii) when in its second configuration, having a sufficient structural integrity, and a sufficient surface profile, such that when the tube is disposed in a bodily passageway so that the deformable helical thread engages the interior wall of the bodily passageway, rotation of the tube will induce a relative movement between the tube and the wall of the bodily passageway and a thread varying element dynamically varying at least one of the height of the deformable helical thread and the rigidity of the deformable helical thread.
