The use of autologous free fat tissue in prevention of calvarial bone regeneration: an experimental study

Autologous free fat grafts have been successfully used to limit ingrowth of postlaminectomy fibrous tissue and to prevent reossification after bone resection in long bones. This study was designed to test the effect of placing autologous adipose tissue in standardized craniotomy defects and also to determine the effect of the presence of periosteum and dura in the area of the fat augmented defects. In 18 immature rabbits, aged 18–21 days, two identical full-thickness defects were made bilaterally in the parietal bone. An autologous free fat graft was placed in one of the defects, the second being an internal control. The study groups were as follows: Group I: dura and periosteum left intact; Group II; periosteum removed; dura left intact; Group III; periosteum and dura removed. The animals were sacrificed after ten weeks. Histological examination of all groups demonstrated prevention of bone regeneration at the margins of the defect with some variations. In the first and second groups, new bone formation appeared over the dura, creating an incomplete plate of bone. On the periosteal side of the graft, a smaller amount of bone formation appeared close to the osteotomy line. The third group demonstrated a total prevention of bone regeneration. The use of free fat tissue graft can prevent calvarial bone regeneration and may be a useful adjunct for the treatment of craniosynostosis. Measures should be taken regarding the new bone formation over the dura, since this may cause reoccurrence of craniosynostosis.