STIMULATION OF ANGIOGENESIS TO IMPROVE THE VIABILITY OF PREFABRICATEDFLAPS

The cutaneous area in a prefabricated myocutaneous flap surviving afte r elevation is dependent on the rate and amount of vascular ingrowth t hat occurs from the underlying muscle. Two modalities, basic fibroblas t growth factor and hyperbaric oxygen, were used separately and togeth er in a prefabricated myocutaneous flap animal model to improve flap s urvival. The semimembranous muscle, based on the saphenous vessels of 40 female Wistar rats weighing between 250 and 325 grams, was tunneled under the ipsilateral abdominal skin and sutured in place. A 3 x 5-cm silicone sheet was placed beneath the muscle flap, and the ipsilatera l epigastric vessels were ligated. Four groups of 10 animals each rece ived one of the following treatment regimes: a 1-ml normal saline infu sion into the saphenous arterial pedicle, a 1-ml infusion of basic fib roblast growth factor (1.0 mu-g/gm of muscle), a 1-ml normal saline in fusion and 14 hyperbaric oxygen treatments, or a 1-ml basic fibroblast growth factor infusion and 14 hyperbaric oxygen treatments. After 1 w eek, the muscle, still based on the saphenous vessels, was elevated wi th a 3 x 5-cm abdominal skin paddle. The flap was sutured back in plac e, leaving the silicone sheet intact. The surviving area of each flap was measured 1 week later after it had demarcated into viable and necr otic regions. Laser Doppler skin perfusion measurements were taken bef ore and after flap elevation and before animal euthanasia. Sixteen fla ps, 4 in each group, were examined histologically for vascularity by m eans of hematoxylin and eosin staining. There was a statistically sign ificant increase in flap survival area when either basic fibroblast gr owth or hyperbaric oxygen was used alone. Further improvement was note d with combination therapy. Histology confirmed improved vascularity i n the basic fibroblast growth factor and hyperbaric oxygen-treated fla ps. This study shows a significant and reliable increase in the area o f prefabricated myocutaneous flap survival using either basic fibrobla st growth factor or hyperbaric oxygen. There is further complementary effect when these two modalities are combined, leading to near complet e flap survival through improved vascularity.