Abstract: A perfusion bioreactor system has an inner chamber and scaffold with matching porosities to equalize fluid flow through a bioreactor. The scaffold can be fabricated using additive manufacturing or other fabrication techniques to match the geometrical shape of a defect, such as a facial bone anomaly. The inner chamber is fabricated in a similar manner and has an inner cavity matching the shape of the scaffold to create a unified structure when assembled together with the scaffold. By matching the shapes of the scaffold and inner chamber, free space is eliminated within the interior volume of the bioreactor. Stem cells can be flowed through the bioreactor and attached to the scaffold, which are then cultured to grow a tissue graft.