Inlay cranioplasty: an experimental comparison of particulate graft versus bone dust.
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.
Clune
James E
JE
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.
Mulliken
John B
JB
Glowacki
Julie
J
Rogers
Gary F
GF
Arany
Praveen R
PR
Kulungowski
Ann M
AM
Greene
Arin K
AK
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*