Abstract: Background and purpose: Free flap has become the main way of reconstruction after surgery for head and neck tumor. Vascular crisis is easy to cause skin flap necrosis, and hypercoagulability is the main cause of vascular crisis. This study explored the factors influencing postoperative hypercoagulability of free flap reconstruction for head and neck tumor, and provided reference for the prevention and treatment of hypercoagulability. Methods: A retrospective analysis was conducted according to the medical records of 243 patients admitted to Department of Otolaryngology, Second Affiliated Hospital of Fujian Medical University from Apr. 2017 to Jul. 2020 who underwent free flap reconstruction for head and neck tumor. The patients were divided into the hypercoagulable group and the non-hypercoagulable group according to whether postoperative hypercoagulable state occurred, and the incidence of postoperative hypercoagulable state and related influencing factors were statistically analyzed. Results: Among the 243 patients, 128 patients had postoperative hypercoagulability, and the incidence was 52.7% (128/243), including 73.4% (94/128) of two postoperative coagulation abnormalities, 21.1% (27/128) of three abnormalities and 5.5% (7/128) of four abnormalities. Results of single factor analysis showed that gender, age, alcoholism, diabetes, tumor stage, surgical repair, intraoperative blood loss, intraoperative blood transfusion, operative time, postoperative leukocyte, postoperative triglyceride, postoperative high-density lipoprotein and postoperative Ca ²⁺ were the possible influencing factors of postoperative hypercoagulability (all P<0.05). Multivariate factor logistic regression analysis showed that diabetes mellitus (OR=1.823, 95% CI: 1.246-4.719), tumor stage (OR=2.155, 95% CI: 1.126-4.126), postoperative leukocyte (OR=1.346, 95% CI: 1.068-2.979) and postoperative triglyceride (OR=3.583, 95% CI: 1.539-8.343) were independent risk factors of postoperative hypercoagulability. Conclusion: Postoperative hypercoagulability of free flap reconstruction for head and neck tumor is more common. For patients with risk factors of diabetes, advanced tumor stage, postoperative high leukocyte and high triglyceride, comprehensive intervention measures should be taken actively.

Key words: Head and neck tumor, Free flap reconstruction, Postoperative hypercoagulability, Incidence, Influencing factors