Risk Factors of Free Flap Complications in Reconstruction for Head and Neck Cancer

Background Although head and neck reconstruction using free flaps has become a common procedure, flap complications remain a concern. This study aimed to analyze the risk factors of free flap complications and to identify the causes of these complications. Methods We studied 97 patients with head and neck cancer with intraoral defects who underwent recon-struction using free flaps at Tottori University Hospital between 2011 and 2020. We used a retrospective cohort study design to investigate whether flap complications, including flap necrosis (total and partial) and flap dehiscence, were related to various factors, including the underlying disease condition, treatment status, and surgical factors.Results Of the 97 patients analyzed, total flap necrosis was observed in one patient (1.0%). The incidence rate of flap complications, including flap necrosis and flap dehiscence, was 29.9%. When the time taken to perform one vascular anastomosis, including preparation of the recipient vessel and flap vessel, exceeded 30 min, the incidence rates of flap necrosis (total and partial) (odds ratio, 8.30; 95% confidence interval, 1.91-36.00; P = 0.005) and flap dehiscence (odds ratio, 3.46; 95% confidence interval, 1.05-11.36; P = 0.041) increased significantly.Conclusion The time taken to perform one vessel anastomosis was the factor that contributed the most to the incidence of flap complications. Reconstructive sur-geons should reduce the incidence of flap complications by keeping the known risk factors of the surgery in mind and by aiming to complete a vascular anastomosis time, including the time taken for the preparation of vessels, of <= 30 min per vessel during surgery.