What makes a good flap go bad? A critical analysis of the literature of intraoperative factors related to free flap failure

Objective: To discuss the various factors related to poor outcome in free flap reconstructions of the head and neck. Study Design: Review of the relevant literature. Methods: A review of the contemporary literature (1995 to present) on free flap reconstruction of the head and neck was undertaken. A literature search on PubMed using the search terms head and neck, reconstruction, free flap, microvascular, failure, complications, fluids, intraoperative, hypertension, hypotension, nitrous oxide, temperature, and morbidity in various combinations was completed. Abstracts were evaluated for prospective and retrospective studies looking at free flap failures. Appropriate articles were selected and analyzed. Results: Evidence exists relating several intraoperative factors to free flap failure. These include greater than 7L intraoperative fluid administration, nitrate and bronchodilator treat, irradiated recipient site, prolonged operative time, and involvement of greater than 1 microvascular surgeon. There is no evidence supporting hypotension, pressors, colloids, and nitrous use in free flap failure. The most common cause of free flap problems relates to failure of using proper surgical technique. Conclusions: Although various dogmas related to the intraoperative care of free flap patients exist, including avoidance of hypotension and pressor use, there is no available clinical evidence to support these practices. Based on the best available evidence the most common cause of free flap complication is failure of proper surgical technique. Although free flap failure is increasingly uncommon, a better understanding of its causes is necessary to avoid this disastrous complication.