Thrombectomy and other treatments are achieved using a catheter having a positioning cage and a macerator within the positioning cage. The catheter is introduced to a target body lumen, typically a blood vessel, and a positioning cage deployed at a treatment site. The macerator is then operated to disrupt thrombus, clot, or other occlusive materials at the treatment site, and the catheter is used to collect and remove the disruptive materials from the body lumen. In particular examples, the macerator may be radially expansible and optionally rotated and/or axially translated within the positioning cage to effect disruption of the occlusive material.