Viability and vascularization of an expanded buttock island flap in the pig.

In 14 of 16 buttock island flaps, half of which had been expanded within their cranial arterial part before elevation, areas of skin necrosis were noted within the caudal random part. The mean area of necrosis on the expanded side did not differ from that on the control side. In vivo angiograms indicated that the circumflex iliac artery was more tortuous and wider on the expanded side than on the control side. The findings suggest that expanding the arterial part of the flaps has no apparent negative effects on the circulation. The concept of expanding skin to be used as a free flap, so that the size of the flap may fulfill demands in special circumstances, is supported.