Cumulative risk factors for flap failure, thrombosis, and hematoma in free flap reconstruction for head and neck cancer: a retrospective nested case-control study

Background:Free flap construction enhances the quality of life for head and neck cancer (HNC) patients; however, complications, such as thrombosis and hematoma, threaten flap survival. This study aimed to identify factors influencing flap failure, thrombosis, and hematoma. Methods:A retrospective nested case-control study was conducted on HNC patients who underwent free flap reconstruction at a tertiary medical center between January 2019 and January 2022. All patients received antithrombotic prophylaxis consisting of prostaglandin E1, dextran, aspirin, and dipyridamole. Risk factors were analyzed using multivariate logistic regression. Results:Among 548 flaps analyzed, flap failure, thrombosis, and hematoma rates were 4.74%, 3.83%, and 9.65%, respectively. Risk factors for flap failure included thrombosis (OR 86.42, 95% CI 15.73-474.89), smoking (OR 49.44, 95% CI 1.28->1000), posteromedial thigh (PMT) flap usage (OR 14.05, 95% CI 2.48-79.54), hematoma (OR 9.68, 95% CI 2.35-39.79), and younger age (OR 0.93, 95% CI 0.87-0.99). Thrombosis risk factors included PMT usage (OR 11.45, 95% CI 2.60-50.38) and anastomosis with the superior thyroid vein (SThV) as the recipient vein after multiple reconstructions (OR 7.91, 95% CI 2.06-30.39). Hematoma risk factors included fibula osteocutaneous flap usage (OR 9.22, 95% CI 2.71-31.42), double-flap usage (OR 8.88, 95% CI 1.80-43.81), liver cirrhosis (OR 6.28, 95% CI 1.44-27.47), and post-surgery hypertension (OR 2.77, 95% CI 1.39-5.50), whereas ipsilateral recurrence (OR 0.14, 95% CI 0.03-0.73) and using the external jugular vein (EJV) as the recipient vein (OR 0.22, 95% CI 0.08-0.61) were protective factors. Conclusion:Thrombosis poses a greater risk than hematoma for flap failure. Utilization of the PMT flap and the SThV markedly increased the risk of thrombosis and flap failure. These findings highlight the importance of antithrombotic prophylaxis and the selection of flaps and recipient veins in recurrent HNC patients.