Treatment of extensive cranial bone defects using computer-designed hydroxyapatite ceramics and periosteal flaps.

We performed cranioplasty using hydroxyapatite ceramics and periosteal flaps in three patients with extensive cranial bone defects. These defects were left after post-brain surgery infection forced the removal of cranial bone. Hydroxyapatite ceramics made by using computer-aided design from three-dimensional computed tomographic image data were implanted in these patients. The defects were relatively large (the largest was 16.5 x 7.5 cm) and had a high degree of curvature. Three pieces were required in one patient, although one piece was sufficient in the other two patients. The surgical technique consisted of removal of the epidural granulation tissue, exposure of the cranial bone defect site, and shaping of the hydroxyapatite ceramics to fit the defect entirely, followed by the implantation of the hydroxyapatite ceramics. In anticipation of induction of the bone to hydroxyapatite, we covered the hydroxyapatite ceramics with periosteal flaps of cranial bones; however, based on only these three patients, our knowledge of the ossification-promoting effect is incomplete. More clinical cases should be investigated to evaluate further the clinical efficacy of this method for treatment. As we have reported here, the treatment of cranial bone defects by using computer-designed hydroxyapatite ceramics and a periosteal flap is safe and highly effective.