Analysis of measured D-dimer levels for detection of deep venous thrombosis and pulmonary embolism after spinal surgery.

STUDY DESIGN

A retrospective clinical study.

OBJECTIVES

To show the prevalence of deep venous thrombosis (DVT) and pulmonary embolism (PE) after spinal surgery using a D-dimer assay followed by screening with computed tomographic (CT) pulmonary angiography and CT venography.

SUMMARY OF BACKGROUND DATA

A few studies on DVT development after spinal surgery have been reported.

METHODS

A complete surveillance examination for DVT and PE was conducted in 88 patients who underwent spinal surgery [male patients, 48; female patients, 40; average age at operation, 62.4 y (range, 17 to 85 y)] through a D-dimer assay combined with CT pulmonary angiography and CT venography. The operation levels were the cervical spine (21 cases), the thoracic spine (16 cases), and the lumbar spine (51 cases). We adopted a D-dimer cut-off point of 10 μg/mL, and classified the patients into high D-dimer (HD; D-dimer level ≥10 μg/mL) and low D-dimer (LD; D-dimer level <10 μg/mL) groups.

RESULTS

Nine (10.2%) patients showed D-dimer levels of ≥10 μg/mL (HD group); of these, 5 patients (5.7%) had DVT. Two (2.2%) of the 5 DVT patients had PE. DVT was evident in 1 (6.2%) of the 16 patients who underwent thoracic procedures and 4 (7.8%) of the 51 patients who underwent lumbar procedures. Statistical comparison between the HD (excluding 5 patients with DVT or PE) and LD groups showed a significant difference in intraoperative blood loss between the groups (P=0.02).

CONCLUSIONS

The D-dimer assay was useful in predicting DVT development. A D-dimer level of ≥10 μg/mL is considered to be a risk factor for thromboembolic disease after spinal surgery. False-positive cases of thromboembolic disease preclude the use of this assay as a stand-alone test for DVT diagnosis. CT venography and CT pulmonary angiography are recommended to confirm thromboembolic disease.