Microvascular free flaps are commonly used in reconstruction for head and neck defects. Failures of these flaps, however, are associated with a significant morbidity and mortality. Flap failures within the first 72 hours are commonly attributed to technical failure of the microvascular anastomosis. However, with standardisation of surgical technique, advanced fellowship training and improved optics and micro-instruments, the survival rates of free flaps have improved significantly.
The authors reviewed the outcomes of 2916 patients who underwent free-flap reconstruction over a 10-year period. There were 133 flap failures (4.6%). However, the majority (60%) of these occurred after 72 hours. A number of factors were found to be associated with flap failure, including intraoperative revision of the anastomosis, reconstruction following resection of a malignant lesion, reconstruction for a chronic fistula, and reconstruction with an osseocutaneous free flap.
Free flaps that failed after 72 hours were more likely to be due to arterial insufficiency, whilst failures within the first 72 hours were more likely due to venous congestion. This work highlights the importance of maintaining vigilance for flap failure beyond the 72 hours immediately postoperatively. It also highlights the need for further work to understand the factors affecting flap survival beyond surgical technique.