Risk Factors of Free Flap Outcomes After Head and Neck Cancer Surgery: A Multivariable Analysis From a Single Center Experience

Risk factors for unfavorable outcomes, such as surgical site infection (SSI) and flap loss, following free flap reconstruction in patients with head and neck cancer are repeatedly reported without a definitive conclusion. Institutional reviews and meta-analyses each have their advantages and limitations. Although this study is without a definitive answer to these questions, it contributes to the literature by identifying potential influencing factors. This single-center cohort study included 596 patients who underwent head and neck reconstruction between 2015 and 2017. Patients were initially divided into two groups based on the presence or absence of SSI, and a similar comparison was made for flap loss. Data were further analyzed using univariate and multivariate logistic regression. The overall SSI rate was 18.29%, with the age of patients (65-74 years, adjusted OR 2.41, p < 0.001; > 74 years, adjusted OR 3.53, p < 0.001) and segmental mandibulectomy (adjusted OR 1.81, p = 0.035) as independent risk factors. The overall flap failure rate was 4.4%, with medial sural flap (adjusted OR 6.89; p = 0.025) and prolonged operative time per hour (adjusted OR 1.38; p < 0.001) identified as significant influencing factors. Age should not be the sole determinant for excluding patients for free tissue transfer, though it may elevate the SSI rate. Special attention is potentially needed during postoperative care for patients who received segmental mandibulectomy, medial sural flap, or experienced prolonged operative time. Identifying these risk factors can assist surgeons in optimizing flap outcomes before head and neck reconstruction.