title: Histological assessment of porous custom-made hydroxyapatite implants 6 months and 2.5 years after cranioplasty.
abstract: BACKGROUND
  In cranial reconstruction, the features of artificial bone differ. Custom-made porous hydroxyapatite (HAp) implants for cranioplasty have been used all over the world because of their good cosmetic, biocompatibility, and osteoconductive properties. Surgical techniques were analyzed, and histological assessment of new bone formation in the hydroxyapatite was performed.
  
  
  METHODS
  Over a 6-year time period, 41 patients underwent cranioplasty using a custom-made three-dimensional hybrid pore structured hydroxyapatite (3DHPoHAp) implant. The surgical techniques and histological evaluations of 3DHPoHAp in 2 cases, removed 6 months and 2.5 years after cranioplasty, are described.
  
  
  RESULTS
  Using 3DHPoHAp, cranioplasty was successfully performed for all patients. The implant fit the bone defect exactly, and surgical manoeuvres were simple and easy. All implants were firmly fixed using a titanium plate, and postoperative infection occurred in 1 patient (2.4%). New bone formation was seen in 2 cases 6 months and 2.5 years after cranioplasty. Osteoblasts were progressing to the stoma at various depths, and bone tissue had ripened. Furthermore, lamellar structure was observed in the case at 2.5 years.
  
  
  CONCLUSIONS
  In this study, there was a low infection rate, and new bone formation was seenin vivoafter cranioplasty. This study also demonstrated that the 3DHPoHAp implant is a good candidate for cranial bone implants because its good osteoconductivity and biocompatibility.
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Toyoko Hospital, Kawasaki City, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Ono
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Toyoko Hospital, Kawasaki City, Japan.
authors.forename: Taigen
authors.initials: T
authors.lastname: Sase
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kawasaki-shi, Kanagawa, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Department of Neurosurgery, St. Marianna University School of Medicine, Kawasaki-shi, Kanagawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takasuna
keywords: Cranioplasty; hydroxyapatite; osteoconductivity; osteointegration; traceability