Disclosed herein are elongate flexible medical devices which are capable of axial elongation through the mechanism of eversion or toposcopic expansion. In general, this may be accomplished by providing a flexible tubular device having a proximal end and a distal end. Retraction of the distal end in a proximal direction through the tubular body inverts the tube upon itself, causing an axial shortening of the overall length of the device. The original length of the device can be restored by coupling a pressurized media to the proximal end of the sleeve. If the distal end of the sleeve is temporarily restricted or closed, the pressurized media causes the distal end of the sleeve to travel distally until the full length of the sleeve has been restored.