TOKYO (AFP) - Japanese hospitals are running a clinical trial on the world's first custom-made bones which would fit neatly into patients' skulls and eventually give way to real bones.

If successful, the Japanese method could open the way for doctors to create new bones within hours of an accident so long as the patient has electronic data on file.

Doctors usually mend defective bones by transplanting real bones or ceramic substitutes. The Japanese implants use a powder of calcium phosphate, the substance that makes up real bones.

The new implants are called CT Bone as they are crafted using the patient's computer tomography (CT) data, a form of medical imaging.