The application relates to a shaft (10) for medical devices comprising an inner tube (11) and an outer tube (12), wherein the inner tube (11) and the outer tube (12) extend concentrically with a common longitudinal axis from a proximal end (15) to a distal end (16) of the shaft (10), and a spiral wall (13) projecting radially outwards from the inner tube (11). Further, the application relates to a catheter having such a shaft (10).