Venous thromboembolism after spine surgery: changes of the fibrin monomer complex and D-dimer level during the perioperative period.

OBJECT

The goal of this study was to determine the incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE) after spine surgery. Another purpose was to clarify the rapid changes of the fibrin monomer complex (FMC) and D-dimer levels during the perioperative period of spine surgery for early diagnosis of venous thromboembolism (VTE).

METHODS

The participants were 72 patients who underwent spine surgery between September 2007 and March 2008. The FMC and D-dimer levels were measured 6 times: 1) at induction of general anesthesia; 2) just after implantation or during surgery; 3) immediately following surgery; 4) 1 day after surgery; 5) 3 days postsurgery; and 6) 7 days after surgery. All patients received mechanical prophylaxis, including compression stockings and intermittent pneumatic compression devices, and all were examined with duplex ultrasonography assessments of both lower extremities and with lung perfusion scintigraphy 7-10 days after surgery. If DVT or PE was suspected, the patient underwent multidetector CT venography.

RESULTS

There were no patients with clinical signs of DVT and PE, but 6 (8.3%) showed VTE, among whom 5 had DVT and 3 had PE. Patients with VTE had significantly higher FMC levels 1 day after surgery, compared with those without VTE (55.9 ± 17.2 μg/ml vs 11.1 ± 2.89 μg/ml; p < 0.01). Patients with VTE had significantly higher D-dimer levels 7 days postsurgery, compared with those without VTE (12.5 ± 2.95 μg/ml vs 4.3 ± 0.39 μg/ml; p < 0.01). Receiver operating characteristic analysis showed that the FMC result was more useful than the D-dimer assay for diagnosis of VTE. When the cutoff value was set to 20.8 μg/ml for FMC, sensitivity was 100% and specificity was 86.3%.

CONCLUSIONS

In this study the prevalence of VTE after spine surgery was 8.3%. The FMC measured 1 day after spine surgery is considered to be useful as an indicator of VTE.