A cross stream thrombectomy catheter with a flexible and expandable cage preferably formed of nitinol for removal of hardened and aged thrombotic material stubbornly attached to the interior of a blood vessel. The cage, which can be mesh or of straight or spiral filament design, is located close to inflow and outflow orifices at the distal portion of a catheter tube and is deployed and extended at a thrombus site for intimate contact therewith and for action of a positionable assembly and subsequent rotation and lineal actuation to abrade, grate, scrape, or otherwise loosen and dislodge difficult to remove thrombus which can interact with cross stream flows to exhaust free and loosened thrombotic particulate through the catheter tube. An alternative embodiment discloses a mechanism involving a threaded tube in rotatable engagement with an internally threaded sleeve to incrementally control the deployment and expansion of the flexible and expandable cages.