Deep vein thrombosis detected after oral cancer reconstructive surgery: a single-center retrospective cohort study with routine postoperative ultrasonographic screening

Deep vein thrombosis detected after oral cancer reconstructive surgery may affect postoperative management, but procedure-specific factors associated with its detection remain incompletely defined. We retrospectively reviewed 201 patients who underwent oral cancer reconstructive surgery and routine lower-extremity ultrasonography within 7 days after surgery. Clinical factors associated with DVT detection were evaluated using multivariable logistic regression. As a secondary exploratory analysis, 20 preoperative laboratory markers and derived indices were evaluated using covariate-adjusted logistic regression with false discovery rate correction for multiple testing. DVT was detected in 49 patients (24.4%). In the primary multivariable model, older age (adjusted OR, 1.05; 95% CI, 1.01–1.09), higher BMI (adjusted OR, 1.17; 95% CI, 1.05–1.30), female sex (adjusted OR, 2.16; 95% CI, 1.02–4.60), and fibula flap reconstruction (adjusted OR, 2.29; 95% CI, 1.11–4.73) were associated with DVT detection. The association with fibula flap reconstruction remained consistent across sensitivity analyses. In the exploratory laboratory analysis, lower ALT showed the strongest nominal association with DVT detection, but no laboratory marker remained statistically significant after false discovery rate correction. DVT was frequently detected after oral cancer reconstructive surgery under routine postoperative ultrasonographic screening. Older age, higher BMI, female sex, and fibula flap reconstruction were associated with DVT detection. Because routine preoperative ultrasonography was not performed, the detected thrombi cannot be definitively classified as newly developed postoperative DVT.