Analyses of the factors influencing bone graft infection after delayed cranioplasty

Background. Several factors influencing bone graft infection after delayed cranioplasty are analyzed in order to reduce the occurrence of infection. Methods. For about 10 years, from March 1995 to February 2005, delayed cranioplasty was performed for 206 cases. The cases comprised 124 males and 82 females. Age distribution of the patients ranged from 6 months to 79 years old. The mean postoperative follow-up period was 1834 days. Autogenous bone, which was preserved in 100% ethanol at -20 degrees C and autoclaved before operation, was used in 54 patients. Polymethylmethacrylate (PMMA) was used in 55 patients. Custom-made PMMA was used in 3 patients. Custom-made titanium mesh was used in 77 patients. Custom-made ceramics (Alumina-ceramics 10 cases and hydroxyapatite 7 cases) was used in 17 patients. Findings. Autoclaved and autogenous bone graft and PMMA have a significantly high rate of graft infection. Titanium mesh has the significantly lowest rate of graft infection. Alumina-ceramic has a merit that it has sufficient strength, however the number of cases using custom-made ceramics including alumina-ceramic was relatively small, and thus we cannot find significant differences in infection rate compared with that of other materials. There was no statistically significant difference in the bone graft infection rate among four categories of preceding diseases; cerebrovascular diseases, head trauma, infectious diseases, and brain tumour. Conclusion. Autoclaved and autogenous bone grafts and PMMA have a significantly higher rate of graft infection. Titanium mesh has the significantly lowest rate of graft infection.