title: Inlay cranioplasty: an experimental comparison of particulate graft versus bone dust.
abstract: BACKGROUND
  Cranioplasty in children is difficult because autologous bone is limited. To expand the calvarial donor site, surgeons have used bone dust harvested with a power drill and particulate bone taken with a bit and brace. The purpose of this study was to compare bone dust and particulate bone for inlay cranioplasty.
  
  
  METHODS
  A critical-size defect was made in the parietal bone of rabbits and managed in three ways: group I (n = 5), no implant; group II (n = 6), bone dust implant; and group III (n = 6), particulate graft implant. Bone dust and particulate graft were obtained using a power burr or brace and bit, respectively. Bone dust and particulate graft volume was calculated using a micrometer. Computed tomography was performed 4, 8, and 16 weeks after cranioplasty to determine ossification; histology also was studied.
  
  
  RESULTS
  The average volume of particulate bone fragments (6.2 × 10 mm) was 344-fold greater than bone dust particles (1.8 × 10 mm) (p < 0.0001). Four weeks postoperatively, the filled volume of the experimental defect was 6.8 ± 4.9 percent in group I, 8.4 ± 7.4 percent in group II, and 43.0 ± 7.2 percent in group III. Eight weeks postoperatively, the filled volume was 22.3 ± 3.9 percent in group I, 29.1 ± 6.7 percent in group II, and 80.0 ± 8.9 percent in group III. Sixteen weeks postoperatively, the defect was closed 38.6 ± 11.1 percent in group I, 41.3 ± 11.2 percent in group II, and 99.3 ± 1.5 percent in group III (p < 0.0001).
  
  
  CONCLUSIONS
  Particulate bone graft ossifies full-thickness cranial defects. Bone dust is ineffective and resorbs, possibly because of its smaller particle size and/or thermal injury during harvesting. Particulate graft, and not bone dust, is suitable for inlay cranioplasty.
authors.affiliation: Boston, Mass. From the Department of Plastic Surgery, Children's Hospital Boston, Harvard Medical School; the Department of Orthopedic Surgery, Brigham and Women's Hospital, Harvard Medical School; and the Program in Oral and Maxillofacial Pathology, Harvard School of Dental Medicine.
authors.forename: James E
authors.initials: JE
authors.lastname: Clune
authors.forename: John B
authors.initials: JB
authors.lastname: Mulliken
authors.forename: Julie
authors.initials: J
authors.lastname: Glowacki
authors.forename: Gary F
authors.initials: GF
authors.lastname: Rogers
authors.forename: Praveen R
authors.initials: PR
authors.lastname: Arany
authors.forename: Ann M
authors.initials: AM
authors.lastname: Kulungowski
authors.forename: Arin K
authors.initials: AK
authors.lastname: Greene
mesh_terms: D000818:Animals; D016025:Bone Transplantation / Q000379:methods*; D003399:Craniotomy; D004195:Disease Models, Animal; D008297:Male; D010012:Osteogenesis / Q000502:physiology*; D010316:Particle Size; D019736:Prostheses and Implants; D011817:Rabbits; D011897:Random Allocation; D019651:Plastic Surgery Procedures / Q000379:methods; D012016:Reference Values; D012886:Skull / Q000601:surgery*