Neovascularized bone, muscle, and myo-osseous free flaps: an experimental model

Different techniques for creating neovascularized bone, muscle, and myo-osseous free flaps were examined and evaluated in an experimental model. Sprague-Dawley rats (n = 40) were divided into four equal groups: 1) cortical bone flap (clam flap); 2) cortical bone and muscle flap (clam-muscle flap); 3) cortical and cancellous bone chip flap (Marlex-mesh flap); and 4) cortical and cancellous bone chip flap (silicone-cone flap). After 3 1/2 weeks, when neovascularization of the flaps developed, they were reliably transferred as free flaps based on their neopedicles. Post transfer, histologic and intravascular latex injections studies were performed, revealing significant differences in the character of neovascularization in the various flaps. The most abundant neovascularization was evident in the cortical bone and muscle (clam-muscle) flap, and the least in one of the cortical and cancellous bone (Marlex mesh) flap preparations. The silicone-cone flap (cancellous bone chips placed in a cone of silicone) neovascularized and maintained bony architecture. This preparation stimulates a hostile wound environment and may prove useful clinically, if similar techniques can be applied to augment vascularization of conventional bone grafts in situ, either as cancellous bone graft or as augmented iliac crest or fibular cortical bone graft. If clinically applicable, flaps created by these techniques may provide versatile alternatives to conventional free flaps.