An extended dorsal island skin flap with multiple vascular territories in the rat: A new skin flap model

Background. The use of various animal skin flap models can lead to difficulty in the interpretation of experimental findings. Establishment of an axial-pattern flap model with predictable necrosis is desirable for the study of the flap pathophysiology. Materials and Methods. Twenty rats were injected with a lead oxide, gelatin, and water mixture through the carotid artery to investigate the cutaneous vascular anatomy. Each cutaneous perforator on the rat dorsum was dissected to its source artery. The skin was removed and radiographed to define its vascular architecture. On the basis of the initial angiographic data, an extended dorsal island skin flap (based on the unilateral deep circumflex iliac artery) measuring up to 8 x 9 cm was designed in 10 rats to assess the viability of the flap. The boundaries of the flap are defined by anatomical landmarks to standardize the flap for rats of different sizes. The upper margin was located at the level of the tip of the scapula and the lower margin at a level 2 cm below the iliac crest. All flaps were observed for 7 days postoperatively and the surviving flap area was calculated as a percentage of total flap dimensions using the paper template technique. Results. Most of the skin of the rat dorsum is supplied by three arteries: the deep circumflex iliac artery (DCIA), the posterior intercostal arteries (PIA), and the lateral thoracic artery (LTA). The DClA anastomoses with the ipsilateral PLA and the contralateral PIA and DCIA The average percentage survival of the skin flap is 70.5 +/- 4.8% (mean +/- SD). Conclusions. The extended dorsal island skin flap has a consistent vasculature and has a predictable distal necrosis area. This new model is felt to be appropriate for skin flap physiological studies, (C) 1999 Academic Press.