Predicting the survival of experimental skin flaps with a knowledge of the vascular architecture.

Experimental skin flaps have been utilized by researchers for almost a century to investigate many of the perplexing questions in plastic and reconstructive surgery, yet the underlying vascular anatomy of these flaps is addressed infrequently. The purpose of this study was to predict the survival of experimental skin flaps prior to their elevation in guinea pigs and rabbits, planned on a knowledge of the underlying vascular anatomy. On the basis of our previous anatomic studies, 17 guinea pigs and 15 rabbits were used in separate experiments. In experiment 1, two parallel flank flaps of identical dimensions were compared on one side of each guinea pig. The dorsal flap encompassed the vascular territories of multiple perforators, while the ventral flap embraced two perforators (two-territory flap). Viability was assessed on days 3 and 7 by inspection and fluorescein dye injection. All ventral flaps survived to a greater extent than the dorsal flaps. Whole-body fresh cadaver lead oxide injections were performed to provide cutaneous angiograms. It was found in each flap that the area of skin viability corresponded to the capture of one to two adjacent vascular territories on the artery at its base. In the second experiment, a multiple-territory osteocutaneous flap was designed on one side of the torso of the rabbit using the Doppler probe. It was based on the thoracodorsal artery and embraced the skin and a 1 x 2 cm segment of iliac crest bone in the adjacent deep circumflex iliac artery angiosome. Using the same criteria as in experiment 1, we found that one to two adjacent viable skin territories were captured on the thoracodorsal artery. In addition, viability of the iliac bone was confirmed in every case by angiography, fluorochrome labeling, and india ink injection studies indicating the capture of deep structures of the deep circumflex iliac artery angiosome. This study reinforces the angiosome concept and indicates that one adjacent vascular territory may be captured reliably in experimental guinea pig and rabbit skin flaps. In addition, we have described a reliable osteocutaneous flap model in the rabbit.