Local and regional spread of tumor cell-sized particles from a femur biopsy in a canine model

The study was designed to investigate the effect of various biopsy procedures on the spread of tumor cell-sized particles to the local tissue and regional lymph nodes. Adult mongrel dogs were anesthetized and the skin covering the distal one-third of the femur was opened from the vastus lateralis to expose the distal femur. A 6 mm diameter biopsy was made through the cortex. In one group, the cortical biopsy opening remained opened while in a separate group the biopsy opening was filled with methyl-methacrylate. A gelatin capsule containing 100,000 fifteen-micron radioactive microspheres was placed next to the biopsy site. A 5F Milar pressure-tipped catheter was placed near the cortical opening prior to closure of the soft tissue and used to monitor hematoma pressure. After the animals received a lethal drug injection, tissues were harvested from the skin and muscle surrounding the femur, from the regional lymph nodes, lung and kidney. The results suggested that hematoma pressure was greatest when the cortical biopsy opening was not plugged with methyl-methacrylate. Spread of the particles to the lymph nodes, lung, and kidney was minimal or nonexistent in both groups. Based on these results, it would appear that plugging the biopsy opening does not prevent the dissemination of cell-sized particles throughout the hematoma area once they have escaped the confines of the bone cortex. In addition, it appears that more than six hours are required for the particles to move to the lymph nodes