New insight into an old paradigm: wrapping and dangling with lower-extremity free flaps.

Flap edema can often compromise an otherwise successful lower-extremity microsurgical reconstruction. To train a flap toward maturity, various wrapping and dangling protocols have been described. Mixed tissue oxygenation of a myocutaneous free flap for lower-extremity reconstruction is examined as measured by ViOptix with wrapping and unwrapping during dangling at different postoperative time points. The results are compared with the nonaffected lower extremity and additional healthy controls. Upon dangling a reconstructed lower extremity, the tissue oximetry recording of a free flap descended rapidly until the leg was reelevated and then continued at this low level with a gradual return to the predangling baseline. The extent of this drop in tissue oxygenation depended upon positioning, and the length of time to reach its baseline upon reelevation decreased as flap matured postoperatively. In addition, wrapping of a reconstructed lower extremity also decreased the overall drop in tissue oxygenation level and the time to recovery while having no effect on the control. Results of this prospective study can lead to an increased understanding of free flap physiology in lower-extremity reconstruction and can further validate and refine our postoperative management strategies regarding dependency and edema control.