Changes of D-dimer level after lumbar fusion surgery and its role in predicting deep venous thrombosis

Objective: To investigate the changes of D-dimer level after lumbar fusion surgery and its role in predicting deep vein thrombosis (DVT). Methods: 92 patients who underwent lumbar fusion surgery were selected based on inclusion and exclusion criteria. All patients underwent color duplex ultrasound of both lower extremities before surgery and 4d after surgery to determine whether there was DVT. All patients underwent serum D-dimer detection within 7d before operation and 2 h, 1, 2, 3, and 5 days after operation. Results: The incidence of DVT after lumbar fusion surgery was 20.6%, of which 78.9% occurred in the calf intermuscular vein and 21.1% occurred in the posterior tibial vein. All patients had no symptoms of DVT. There was no significant difference in D-dimer levels between the two groups before operation, and D-dimer levels increased after operation both two groups. D-dimer level in DVT group was significantly higher than that in non DVT group at 3 and 5 days after operation (P < 0.05). A receiver operating characteristic curve analysis showed that the cut-off value of D-dimer level for predicting DVT was 2.745 mg/L at 3d after operation, with a sensitivity of 78.9% and a specificity of 79.5%. Conclusion: Taking D-dimer 2.745 mg/L as the cut-off value at 3d after operation, it has a good predictive efficiency for the occurrence of DVT after lumbar fusion surgery.