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The success rate for free tissue transfer is now more than 95%1,2 because of improved pro-cedures and increased knowledge of vascular supply patterns of the flaps. Initial success rates are approaching 100%. Nevertheless, a transferred flap can be lost, and microsurgeons expend considerable effort to salvage the failing flap or at least manage the flap conservatively.3 The importance of postop-erative flap monitoring for early detection of circula-tory disturbance is therefore understood. Althoug