Paediatric cranial defect reconstruction using bioactive fibre-reinforced composite implant: early outcomes

In children, approximately half of cryopreserved allograft bone flaps fail due to infection and resorption. Synthetic materials offer a solution for allograft bone flap resorption. Fibre-reinforced composite with a bioactive glass particulate filling is a new synthetic material for bone reconstruction. Bioactive glass is capable of chemically bonding with bone and is osteoinductive, osteoconductive and bacteriostatic. Fibre-reinforced composite allows for fabricating thin (0.8 mm) margins for implant, which are designed as onlays on the existing bone. Bioactive glass is dissolved over time, whereas the fibre-reinforced composite serves as a biostable part of the implant, and these have been tested in preclinical and adult clinical trials. In this study, we tested the safety and other required properties of this composite material in large skull bone reconstruction with children. Eight cranioplasties were performed on seven patients, aged 2.5-16 years and having large (> 16 cm(2)) skull bone defects. The implant used in this study was a patient-specific, glass-fibre-reinforced composite, which contained a bioactive glass particulate compound, S53P4. During follow-up (average 35.1 months), one minor complication was observed and three patients needed revision surgery. Two surgical site infections were observed. After treatment of complications, a good functional and cosmetic outcome was observed in all patients. The implants had an onlay design and fitted the defect well. In clinical and imaging examinations, the implants were in the original position with no signs of implant migration, degradation or mechanical breakage. Here, we found that early cranioplasty outcomes with the fibre-reinforced composite implant were promising. However, a longer follow-up time and a larger group of patients are needed to draw firmer conclusions regarding the long-term benefits of the proposed novel biomaterial and implant design. The glass-fibre-reinforced composite implant incorporated by particles of bioactive glass may offer an original, non-metallic and bioactive alternative for reconstruction of large skull bone defects in a paediatric population.