A new design of a dorsal flap in the rat to study skin necrosis and its prevention

SummaryBackgroundThe Mcfarlane flap or dorsal pedicled flap has become the standard model for pedicled rat skin flap study but its reliability has been called to question. In the past, there were possible confounding variable with the McFarlane flap and various methods were used to adjust these variables. We have developed a new model for studying skin flap necrosis and its prevention that eliminates these confounding variables.MethodsThe flap is a significant modification of the McFarlane flap where we form a blind ended pedicled tube using a 3 cm × 9 cm dorsal flap. Survival area is measured using digital photography and computer assisted analysis. This new flap is compared with the standard McFarlane flap with n = 25 in each group.ResultsThe mean survival area of the new flap (15.673 cm2 + SD3.37) is comparable with the McFarlane flap (18.904 cm2 + SD3.79). The relative merit lies in the elimination of the confounding variable of the graft bed influence on our flap without a significant reduction in the survival area.ConclusionA new rat model is presented that may be used in studying the effect of various treatment modalities on pedicled skin flaps. This model has the benefit of eliminating graft bed effect without the risk of flap and wound infection or desiccation that have been encountered using other models. The new flap also has better demarcation of necrosis area in this study.