Risk Factors for Free Flap Failure in 2,846 Patients With Head and Neck Cancer: A National Database Study in Japan

The risk factors for an unfavorable outcome after microvascular free flap reconstruction in head and neck cancer are not fully understood. We sought to identify factors affecting the occurrence of free flap failure.This was a retrospective cohort study using data from the national inpatient database in Japan between 2010 and 2012. We identified patients diagnosed with head and neck cancer who underwent tumor resection and consecutive free flap reconstruction. Cox proportional hazards regression was used to assess risk factors for free flap failure. The threshold for significance was P < .05. Missing data were imputed by using multiple imputation.We identified 2,846 eligible patients. The overall proportion of free flap failure was 3.3%. Free flap failure was associated with diabetes mellitus (hazard ratio [HR], 1.80; 95% confidence interval [95% CI], 1.18 to 2.76; P = .007), peripheral vascular disease (HR, 4.49; 95% CI, 1.61 to 12.52; P = .004), renal failure (HR, 3.67; 95% CI, 1.45 to 9.33; P = .006), preoperative radiotherapy (HR, 2.14; 95% CI, 1.11 to 4.13; P = .022), and duration of anesthesia greater than 18 hours (compared with <12 hours; HR, 2.72; 95% CI, 1.19 to 6.22; P = .018).Diabetes mellitus, peripheral vascular disease, renal failure, preoperative radiotherapy, and a longer duration of anesthesia were significant predictors of the occurrence of free flap failure.