engleski

Vascularised Bone Created by Epigastric Flap Prefabrication with Bone Morphogenetic Protein 7

ABSTRACT Introduction Repair of large bone defects can still be a problem. Vascularized bone transfer has greatly expanded our options for reconstruction of such defects but the donor site morbidity and limited number of donor sites limit its use. If we could prefabricate the needed bone size and shape in any standard flap we would greatly expand our reconstructive options and reduce the donor site morbidity thus improving the overall functional and aesthetic result. In this study we investigated the possibility of prefabrication of bone in the epigastric flap of the rat using Bone morphogenetic protein 7 (BMP7) and the usefulness of the prefabricated vascularized bone in reconstructing long bone defects of the rat femur. Material and Methods Seventy two male Wistar rats were used in this study. They were divided into six groups. Collagen sponge or dematerialized bone was treated with a low (30mg) or high (120 mg) dose of BMP7 or with diluent only. The BMP7 or diluent treated carrier was then inserted under the epigastric flap in the rat groin. After six weeks, when the new bone was formed, a gap of 0.8 cm was formed in the ipsilateral femur of each rat. This defect was reconstructed with the bone in the prefabricated epigastric flap. The stabilization was performed with an intramedullary K-wire. Eight weeks after the defect was reconstructed the animals were sacrificed and the reconstructed femurs were harvested. The healing in different groups was assessed by X-ray, examination and histology. Results The examination and histological analysis of the bone in the prefabricated flaps showed that BMP-7 stimulated bone formation in both the collagen sponge and demineralized bone implants irregardless of the dose. Examination, X-ray and histology of the femur specimens showed healing of bone defect reconstructed with the vascularized prefabricated bone in the high dose BMP-7 groups (both collagen sponge and de mineralized bone matrix) Demineralized bone matrix was found to be superior to collagen sponge in supporting bone formation both in the epigastric flap and in the femur bone defect. Non-union was found in most femurs reconstructed with flaps that were prefabricated with low BMP-7 dose implants and all femurs reconstructed with flaps prefabricated with diluent treated implants. Conclusion The results of this study in rats suggest that bone can be successfully formed in a soft tissue flap using BMP7 and used to reconstruct long bone defects which would otherwise result in non union.

Flaps; Prefabrication; BMP7

nije evidentirano