Trauma patients have the highest risk of VTE among hospitalised patients1, with a reported 13-fold increase of risk2. Due to the heterogeneity of injuries, the true incidence of VTE in trauma patients is difficult to obtain. This study examines the incidence of VTE and associated complications in trauma patients with lower limb injuries.

Between 2005 and 2009, patients over 18 years of age with lower limb injuries and/or fractures that were either isolated or a part of multi-systemic injuries were included in the study. Further stratification was performed according to the Injury Severity Score: an ISS greater than 15 was a major (trauma); less than 15, a minor. The mode of VTE prophylaxis, type of surgery, and bleeding complications were also examined.

There were 5528 patients in the minor trauma group, and 509 in the major trauma group. Minor trauma: the mean age was 58.1 years (range: 18 – 104). The VTE incidence was 1.2%: 0.67% for DVT, and 0.5% for PE. The readmission rate within a three-month period was 11%, of which 2.8% were due to VTE with 13 cases of DVT, and 5 cases of PE. The 30-day mortality rate was 2.2%. Seven patients died from PE during admission, while one died from PE within three months after discharge.

Major trauma: the mean age was 42.5 years (range: 18 – 95). The overall VTE incidence was 7.8%: 5.9% for DVT, and 0.9% for PE. The readmission rate within a three-month period was 7.6%, of which 5% were due to VTE with 2 cases of DVT. The overall 30-day mortality rate was 11.1%, and there was no formally-diagnosed fatal PE during admission or post-discharge.

Major trauma patients had a 7-fold increased risk of developing VTE during admission when compared to minor trauma patients, although minor trauma patients had more fatal PEs. Additionally, major trauma patients had a 10-fold increased risk for DVT, and a 3-fold risk for PE, when compared with minor trauma patients. No significant difference was detected between the two groups for the 30-day readmission rate due to VTE.

Introduction A prospective cohort study was conducted to assess the incidence of venous thromboembolism (VTE) in 300 patients undergoing elective spinal surgery. Although this subject has been extensively studied in patients undergoing joint replacement surgery, the true incidence of VTE related to spinal surgery remains unknown. We also sought to assess the efficacy of various forms of VTE prophylaxis, another area which has not been adequately studied.

Methods Bilateral lower extremity venous duplex scans were performed pre-operatively, within one week postoperatively and at 4 to 6 weeks post-operatively. Information was collected regarding age, gender, body mass index, type and duration of surgical procedure, intra-operative blood loss and blood transfusion, pre- and post-operative mobility and other risk factors for VTE. All patients received vigorous mechanical prophylaxis with 56% of patients receiving pharmacological prophylaxis (unfractionated or low molecular weight heparin) according to surgeon preference.

Results The overall incidence of post-operative deep vein thrombosis (DVT) was 3.4%. The incidence in those receiving pharmacological prophylaxis was 1.2% versus 6.3% in those who received mechanical prophylaxis alone (p< 0.05). Just under half of the post-operative DVTs (1.4%) occurred after hospital discharge with none of these patients receiving heparin. There were two cases of pulmonary embolism (0.7%), both occurring during hospitalization, and there were no deaths. There was no difference in blood loss or transfusion rates between patients receiving or not receiving pharmacological prophylaxis and there were no serious complications related to blood loss. There was a surprisingly high incidence of abnormalities detected on pre-operative scanning, with DVT occurring in 3.0% and superficial thrombophlebitis in 24.8%.

Discussion The incidence of DVT in patients after spinal surgery was 3.4% and was significantly lower (1.2 %) in patients who received pharmacological prophylaxis. Given that the rates of bleeding-related complications were not different between the two groups, we conclude that it is both efficacious and safe to use pharmacological prophylaxis in combination with mechanical prophylaxis routinely in patients undergoing spinal surgery. A 27.8% incidence of pre-operative venous abnormalities may reflect pre-operative immobility due to pain in this group of patients, and justifies the use of ultrasound scanning as an important pre-operative screening tool. In addition, the high incidence of late-onset DVT justifies the need for follow-up scanning several weeks after discharge. This study is the amongst the largest of its type to date, however a larger, randomized and controlled trial is now necessary to confirm these results and allow the formulation of unambiguous guidelines for spinal surgery and VTE prophylaxis.