ABSTRACT
Restoration of the mandible after defects caused by ablative surgery remains challenging. Microvascular free flaps from the scapula, fibula or iliac crest remain the 'gold standard'. A drawback of these methods is donor-side morbidity, availability and the shape of the bone. Former cases have shown that prefabrication of a customized bone flap in the latissimus dorsi muscle may be successful; however, this method is still associated with high donor-side morbidity. Osteogenesis in the omentum majus of rabbits by wrapping the periosteum into it was confirmed recently and is particularly interesting for bone endocultivation. Twelve adult male New Zealand white rabbits were used. In each, two hydroxyapatite blocks were implanted in the greater omentum with autologous bone or autologous bone + rhBMP-2. Bone density measurements were performed by CT scans. Fluorochrome labelling was used for new bone formation detection. The animals were sacrificed at week 10, and the specimens were harvested for histological and histomorphometric analysis. In histological and fluorescence microscopic analysis, new bone formation could be found, as well as new blood vessels and connective tissue. No significant differences were found regarding the histological analysis and bone density measurements between the groups. It could be demonstrated that the omentum majus is a practical way to use one's own body as a bioreactor for prefabrication of tissue-engineered bony constructs. Regarding the influence and exact dose of rhBMP-2, further research is necessary. To establish and improve this method, further large-animal experimental studies are also necessary.
Subject(s)
Omentum , Osteogenesis , Animals , Bone Transplantation , Male , Periosteum , Rabbits , Surgical Flaps , Tissue EngineeringABSTRACT
The reconstruction of defects in the mandible are still challenging. Despite several adequate microvascular bone reconstruction techniques, there is a need for ectopic bone endocultivation without drawbacks by donor-site morbidity. The omentum majus is described as a good vascularized fleece with undifferentiated cells with potential for bone culturing. In the omentum majus of six rabbits, two hydroxyapatite blocks were incorporated for 12 weeks each. The blocks were prepared with recombinant human bone morphogenetic protein-2 (rhBMP-2) or VEGF165 + rhBMP-2 and wrapped into the omentum. For ectopic bone endocultivation observation computed tomography (CT) scans were performed, and fluorescence markers were applied. After harvesting the block, histological sections were performed with hematoxylin and eosin and toluidine blue staining. In the CT scans, the Hounsfield units of the blocks increased within the trail. In some sections, new bone formation was observed within the hydroxyapatite blocks, however, the histological staining showed soft-tissue invasion only, no gross bone formation was observed. The ectopic bone endocultivation in the omentum majus is technically a good approach. An adequate mixture of osteoinductive proteins is still missing.
