Techniques of external monitoring of buried free flaps

Postoperative monitoring of free tissue transfer has proven to be crucial in enhancing the flap salvage rate in the event of thrombosis of the anastomosed vessels. Unfortunately, for buried flaps in the head and neck, direct monitoring of the flap can be extremely difficult, if not impossible. Utilizing various methods of flap exposure in a series of 55 buried free flaps of the head and neck, we demonstrate that we were able to provide a reliable means of direct postoperative assessment of the free flaps. Exteriorized components (indicator flaps) were established for 52 cases. An incision to create a skin window in the neck for monitoring was used for 3 cases. For the exteriorized flaps, in addition to clinical observation, adjunctive continuous monitoring using laser Doppler flowmetry was employed for 4-5 days. One free flap developed vascular thrombosis, which was re-explored and salvaged, giving a flap success rate of 100%. Fifty of 52 (96.2%) external components remained viable and therefore reliable for monitoring the main body of the flap. Two indicator flaps were unreliable after postoperative day 1 due to poor skin perfusion, while the subcutaneous component clinically remained viable. There was no return to the operating room for false-positive reexploration. This series reinforces the feasibility and reliability of direct monitoring of buried free flaps using the laser Doppler in practically all cases when modification is added to the flap design and inset.