Ectopic bone formation in rats: comparison of biphasic ceramic implants seeded with cultured red bone-marrow cells in a pedicled and a revascularized muscle flap (Master class in plastic surgery)

A series of studies have been carried out with the aim of developing a method for microsurgical reconstruction of bone defects with the help of tissue-engineering techniques. In this study we determined how microsurgery affects the bone-forming capacity of the final construct. Sixteen ceramic implants together with cultured cells were implanted into the adductor thigh muscle flap of the rat. The flap was enveloped by a silicone sheet. After 4 weeks, the pedicles of eight flaps were cut and directly anastomosed microsurgically. The other eight flaps were given a sham operation, in which all branches of the pedicle were cut and ligated, but the main pedicle was left intact. Four weeks after the second surgery, all implants were harvested and analyzed by histology and histomorphometry. The histological appearance of the bone was found to be similar in both groups. Histomorphometry did not reveal statistically-significant differences in bone formation. Thus, we conclude that in a rat model viable microsurgical bone flaps can be obtained by using a cell-based tissue-engineering approach.