Development of titanium fixation screw for hydroxyapatite osteosynthesis (APACERAM)

BackgroundCranioplasty using custom-made HAP ceramic implants is a common procedure for skull defects. However, miniplate fixation using commercially available screws to stabilize the HAP flap is associated with several problems due to characteristic brittleness. The authors have thus developed a suitable screw for this procedure.MethodsHydroxyapatite blocks (porosity, 40%; thickness, 5 mm) were prepared. Holes were created using a φ1.4-mm drill. Five types of screw were evaluated for HAP condition after insertion, fixation strength on pull-out test, and fasten plate strength based on maximum torque.ResultsBased on this evaluation, the most effective screws were cylindrical style in shape, 4.8 mm in effective length, φ1.6 mm in effective diameter, and 0.2 mm in edge height.ConclusionsA novel screw with high fixation potential for the miniplate technique was developed in this study.