For the purpose of determining possible passive dissemination of tumor
cells from a bone biopsy site, we created an animal model. A cortical
window was placed in the canine femur and a measured quantity of
radioactive microspheres was placed in the medullary canal. Local and
distant spread of the microspheres were measured four days after the
simulated biopsy. In the animals in which the cortical window was left
open, spread of the microspheres was limited to the adjacent tissue and the
regional lymph nodes. In the animals in which the bone window was plugged
with methylmethacrylate, there was little or no local spread of the
microspheres; however, there was significant uptake of the microspheres in
the lung. In a separate trial, significant microsphere activity was present
in the lung within twenty minutes after placement of the methylmethacrylate
plug.