A method and a system for assisting a wire guide to cross obstructed ducts in mammalian body are described. The method and system is based on applying pulsed energy to occlusion obstructing the duct. The pulsed energy is applied by means of an auxiliary probe. The auxiliary probe is relatively displaceable with respect to the wire guide along a lumen provided within the probe. The distal region of the probe is provided with enhanced flexibility comparing with the reminder portion of the probe.