Analysis of D-dimer levels for the detection of deep venous thrombosis for patients with spinal metastasis undergoing decompression with fixation.

Background: Deep venous thrombosis (DVT) after spinal surgery has recently attracted increasing attention. Patients with spinal metastases who undergo decompression with fixation are at a high risk of developing DVT. D-dimer levels indicate the risk of DVT, and the purpose of our study was to investigate D-dimer levels as a predictor of DVT perioperatively.

Methods: We prospectively evaluated 100 patients with spinal metastases. D-dimer tests were performed twice: once before surgery and one day postoperatively. DVT was diagnosed by duplex ultrasonographic assessment of both lower extremities. Pulmonary embolisms (PEs) were diagnosed using multidetector computed tomography and pulmonary angiography. Perioperative serum D-dimer levels were compared between the DVT (+) and DVT (-) groups. The cutoff value of the D-dimer level was calculated using receiver operating characteristic analysis.

Results: Preoperative and postoperative DVT prevalences were 8.0% (8/100) and 6.6% (6/91), respectively, and none of the patients developed PE. Before surgery, there was no significant differences in D-dimer levels between the pre-DVT (+) and pre-DVT (-) groups. After surgery, the D-dimer level one-day postoperatively for the post-DVT (+) group (17.6 ± 11.8 mg/L) was significantly higher than that of the post-DVT (-) group (5.0 ± 4.7 mg/L). The cutoff value of the postoperative D-dimer level was 9.51(mg/L), and the sensitivity and specificity for the optimum threshold were 83.3% and 89.4%, respectively.

Conclusions: Our findings suggest that preoperative D-dimer level may not be a predictor of DVT. Preoperative ultrasound examinations should be routinely performed in patients with spinal metastases. Postoperative D-dimer levels greater than 9.51(mg/L) are a predictive factor for the early diagnosis of DVT after spine surgery.

Trial Registration: Our study was registered on Chinese Clinical Trial Registry (No.ChiCTR2000029737). Registered 11 February 2020 - Retrospectively registered, https://www.chictr.org.cn/index.aspx.