Spinal cord compression by epidural metastases. Fibrosarcoma experiments in rats

Morphologic changes were studied in 43 rats that were paralyzed by an epidural fibrosarcoma inoculated through the spinous process. By this technique, of 29 rats examined radiographically, the tumor destroyed vertebral bone in 22. Changes of the cord in the early stage of paralysis were specially analyzed by Marchi's stain and microangiograms. In compromised cord segments in the early stage, extravasation of contrast medium was observed in the gray matter and the dorsal funiculus; and in the dorsal funiculus just proximal or distal to the compressed portion, hemorrhagic areas were present. Ascending degenerated fibers in the dorsal funiculus, which were derived from the degenerated posterior nerve root or the degeneration of the dorsal funiculus in the compressed segments, were characteristically detected in rats in the early stages. In the advanced stages a transverse cord lesion was observed at the involved level. Based on the present analyses, to prevent more advanced damage to the spinal cord, the tumor should be removed at an early stage that clinically coincides with the period when radicular signs appear.