While you are awake and pain-free (using local anesthesia), bone marrow is removed from the top of the hip bone (iliac crest). The bone marrow is filtered, treated, and may be transplanted immediately. Other times it's frozen and stored for later use. The bone marrow is then transfused through a vein (IV line). It naturally transports itself back into the intended bone cavities, where it grows quickly to replace the old bone marrow.