A preliminary report of percutaneous craniofacial osteoplasty in a rat calvarium.
OBJECTIVES/HYPOTHESIS
To evaluate the potential for injectable, permanent bone augmentation by assessing the biocompatability and bioactivity of subperiosteal hydroxylapatite (Radiesse) deposition in a rat model.


STUDY DESIGN
Randomized controlled animal model.


METHODS
Fourteen adult Sprague Dawley rats were injected in the parietal skull with 0.2 ml of hydroxylapatite (10 animals) or 0.2 ml of a carrier gel control (4 animals), using a subperiosteal injection technique on the right and a subcutaneous injection technique on the left. At 1, 3, and 6 months, three rats (1 negative control, 2 variables) were sacrificed and the calvaria were harvested. At 12 months, the remaining five rats were sacrificed. After each harvest, the specimens were processed and then examined under both light and polarized microscopy for new bone growth at the injection sites.


RESULTS
The inflammatory response was limited with both hydroxylapatite and carrier injections. Injectables were still present 12 months after the injection. New bone formation was only observed when the injection was located deep to a disrupted periosteum The odds of new bone formation was 48.949 times higher (95% confidence intervals CI [2.637, 3759.961]; P=0.002) with subperiosteal hydroxylapatite injections compared to all other combinations of injection plane and injectable.


CONCLUSIONS
This preliminary report of subperiosteal hydroxylapatite (Radiesse) injection in a rat model has verified the biocompatibility of injectable hydroxylapatite at the bony interface and suggests the potential for new bone formation.


LEVEL OF EVIDENCE
N/A.
['Parkes|William J|WJ|', 'Greywoode|Jewel|J|', "O'Hara|Brian J|BJ|", 'Heffelfinger|Ryan N|RN|', 'Krein|Howard|H|']
D000818:Animals D001672:Biocompatible Materials D060826:Cementoplasty D004195:Disease Models, Animal D017886:Durapatite D007267:Injections D010294:Parietal Bone D051381:Rats D017207:Rats, Sprague-Dawley D012887:Skull Fractures
Osteoplasty hydroxylapatite