This pilot study aims to demonstrate the safety and effectiveness of using the patient's own mesenchymal stem cells in cranial reconstruction. The trial being conducted at the Royal Perth Hospital in Western Australia from January 2013 to December 2015 and expects to enrol 10 participants who require cranial reconstruction as a result of surgery or trauma. This trial proposes to use an implant that is customised to match the skull defect and is a sandwich of a scaffold embedded with mesenchymal stem cells that have been harvested from the patient and expanded in the laboratory. It is expected that the stem cells will multiply to occupy the scaffold with bone generating cells, which will eventually replace the entire scaffold with new bone. Participants will be assessed for complications. Bone formation will be monitored by CT scanning.