Association Between Early Heparin Prophylaxis and Risk of Venous Thromboembolism Through Two Months After Spine Fusion for Spinal Metastasis: A Retrospective Cohort Study of United States Academic Health Centers

Study DesignRetrospective Cohort Study.ObjectiveEvidence on chemoprophylactic anticoagulation efficacy in preventing venous thromboembolism (VTE) after spine surgery for metastasis is scarce. We hypothesized that early heparin administration (0-2 days post-surgery) significantly reduces VTE risk post-arthrodesis. We also examined VTE incidence and risk over 2 months and severe postoperative bleeding (SPOB).MethodsWe conducted a retrospective cohort study using the TriNetX network, identifying adults who had a spinal arthrodesis for spinal metastasis in the past 20 years. Patients were grouped by anticoagulation use: a heparin cohort and a non-anticoagulated control. After propensity matching for key VTE risk factors, we examined VTE risk ratios (RR) with 95% confidence intervals (CI) up to 2 weeks post-surgery, and incidence and RR of VTE and SPOB over 2 months.ResultsThere were 847 patients per cohort after matching. There was no statistically significant difference in incidence of VTE in the heparin group compared to the no anticoagulation cohort through 2-weeks' (4.0% vs 2.7%; RR: 1.48; 95% CI: 0.88, 2.49; <i>P</i> = 0.1383) and 2 months' follow-up (9.4% vs 7.9%; RR: 1.2; 95% CI: 0.88, 1.63; <i>P</i> = 0.2619). Furthermore, there was no statistically significant difference in incidence of SPOB in the heparin group compared to the no anticoagulation group at 2-weeks' (1.5% vs 1.7%; RR: 0.93; 95% CI: 0.44, 1.96; <i>P</i> = 0.8462) and 2-months' follow-up (2.8% vs 2.5%; RR: 1.1; 95% CI: 0.64, 2.04; <i>P</i> = 0.6504).ConclusionEarly heparin administration did not significantly affect VTE or SPOB rates compared to controls. Future research should explore whether other anticoagulants lower VTE risk post-spinal metastasis fusion.