title: Development of titanium fixation screw for hydroxyapatite osteosynthesis (APACERAM).
abstract: BACKGROUND
  Cranioplasty 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.
  
  
  METHODS
  Hydroxyapatite blocks (porosity, 40%; thickness, 5 mm) were prepared. Holes were created using a phi 1.4-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.
  
  
  RESULTS
  Based on this evaluation, the most effective screws were cylindrical style in shape, 4.8 mm in effective length, phi 1.6 mm in effective diameter, and 0.2 mm in edge height.
  
  
  CONCLUSIONS
  A novel screw with high fixation potential for the miniplate technique was developed in this study.
authors.affiliation: Department of Neurosurgery, Yokosuka Kyousai Hospital, Yokosuka, Kanagawa 2380011, Japan. yoshihidet@aol.com
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D001672:Biocompatible Materials; D001860:Bone Plates; D001863:Bone Screws; D003399:Craniotomy / Q000295:instrumentation*; D017886:Durapatite; D004867:Equipment Design; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D008422:Materials Testing; D008954:Models, Biological; D016062:Porosity; D013718:Tensile Strength; D014025:Titanium
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite; D014025:Titanium