Harvesting blood stem cells from cranial bone at craniotomy--a preliminary study.

Primary brain tumors seldom infiltrate into the cranium, even if they are invasive in the central nervous system. In this study, we examined whether blood stem cells can be harvested from cranial bone at craniotomy. Bone marrow cells in cranial bone were counted in 181 craniotomy specimens after staining with hematoxylin and eosin. Marrow volume was measured in 37 specimens using three-dimensional computed tomography (CT). In 10 cases, viable cells collected from very small bone pieces at craniotomy were cultured to examine granulocyte/macrophage colony-forming units (CFU-GM). In 2 cases, bone marrow cells were practically harvested from removed bone at surgery. The weight of bone flap at craniotomy was 35.0 +/- 18.0 g. Bone flap marrow contained 1.5 x 10(9) cells/ml. CT examination showed that bone flap volume was 35.0 +/- 9.0 ml and marrow ratio was 65.1 +/- 13.5%. Thus, at craniotomy, a typical bone flap contained about 3.4 x 10(10) cells. Bone marrow cell count gradually decreased as subject age increased. The bone pieces obtained at craniotomy contained 3.1 +/- 3.4 x 10(6) cells/g, and CFU-GM count was 0.4 x 10(5) cells/g. In one case, we collected 3.4 x 10(8) cells, including 1.8 x 10(6) CFU-GM colonies. In another case, we collected 9.7 x 10(8) cells, including 4.8 x 10(6) CFU-GM colonies. These findings indicate that, at craniotomy, the number of blood stem cells in a typical bone flap is sufficient for autologous blood stem cell rescue.