Effects of different vascular patterns and the delay phenomenon on rat ventral island flap viability

The objective of the current study was to investigate flap viability and to determine optimal delay time by designing various blood flow patterns in the superficial inferior epigastric (SIE) artery (A) and vein (V) flap model. Flaps measuring 7 x 7 cm were created in 42 Sprague-Dawley rats, which were divided into six groups. In group I rats (AV-AV), the flap was elevated based on the bilateral SIE vessels. In group II rats (AV-A), the flap was elevated based on the right SIE vessels and the left artery. In group III rats (V-AV), the flap was elevated based on the left-side vein whereas the SIE artery and vein were the pedicle on the right side. In group IV rats (V-A), the flap was elevated as a venous flap on the left side and was SIE artery based on the right side. In group V rats (AV-) the flap was elevated based on the right SIE artery and vein. In group VI rats (delay), the SIA artery and vein on the left side were ligated without elevation during the first session. The flap was elevated on the right SIE artery and vein 7 days after the delay procedure. Percentages of viable flap surface area were measured in millimeters with acetate paper on day 5 after surgery. The highest viability was seen in group I rats (96.14%), and the delay group had the second highest viable area (88.56%). The area that remained viable in group II was larger than that of group III (87.41% vs. 72.84%; p < 0.05). The least viable areas were observed in group IV. The percentage of viable flap area was significantly higher in the delay group when compared with group V rats (88.56 +/- 1.06% vs. 60.01 2.58%; p < 0.05). In conclusion, if the contralateral pedicle is ligated 7 days before SIE vessel-based island flap elevation, the flap can be used safely in a manner that crosses the median. Artery inflow of the flap is more important than venous outflow for improvement of flap viability on the contralateral side.