Tiam Mana Saffari

63 THE SUPERFICIAL INFERIOR EPIGASTRIC ARTERY FASCIA FLAP IN RATS 3 DISCUSSION The surgical technique for the rat SIEF flap harvest was described and evaluated. While this flap has been reported previously in a few animal studies 17,19,20 , long-term viability has not been adequately assessed or determined. Additionally, a succinct and detailed description of this technique in rats has not been illustrated or reported. The main findings of this study were that the SIEF flap is an easy flap to raise and remains viable in all rats after either a 12 or 16 weeks survival period. Complications included two lymphoceles and one hematoma acutely, but no long term consequences at 12 and 16 weeks. The flap demonstrated to have 100 percent success rates after elevation without flap failure or necrosis at the donor site. One major advantage is that the SIE vessels of the rat are approximately 0.5 mm in diameter 30 , which categorizes it as relatively large andmakes them to be easily dissected under loupe magnification. By only including the lateral branch, necrosis at the donor site is prevented. This flap design can be applied to other rat strains as well as rats of different sizes as the anatomical branches are easily recognized. The pedicled flap eliminates the need for microvascular anastomosis and minimizes flap failures secondary to surgical techniques. This pedicled flap allows for a technically simple elevation without intramuscular dissection and a relatively short operation time. An additional benefit is that the transplanted adipofascial tissue can improve blood flow in adjacent tissues such as bone, nerve and muscles and be a readily applied pedicle flap for studies on vascularization 20,31 . The inclusion of adipofascial tissue in the flap decreases intravascular resistance of the bundle, resulting in improved blood flow in the flap which decreases the risk of thrombosis 20,31 . Immunohistochemical qualitative analysis of the nerve samples confirms the increase in vascularity in the SIEF group (vascularized flap wrapped around the processed nerve allograft) in both H&E and anti CD-34 sections at 12 weeks. Vasculature is known to play a crucial role in supporting nerve regeneration following injury 32 . A lack of blood supply could lead to nerve hypoxia and damage, leading to nerve fibrosis 33,34 . At time of a nerve injury, Wallerian degeneration is activated causing Schwann cell proliferation distal to the nerve injury 35,36 . This process causes blood vessels to precede Schwann cell migration and to stimulate axonal extension, describing