Chemoprophylactic Anticoagulation Following Lumbar Surgery Significantly Reduces Thromboembolic Events After Instrumented Fusions, Not Decompressions

Chemical prophylaxis and venous thromboembolism following elective spinal surgery: A systematic review and meta-analysis

Background

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a potentially devastating complication after surgery. Spine surgery is associated with an increased risk of postoperative bleeding, such as spinal epidural hematomas (SEH), which complicates the use of anticoagulation. Despite this dilemma, there is a lack of consensus around perioperative VTE prophylaxis. This systematic review investigates the relationship between chemoprophylaxis and the incidence rates of VTE and SEH in the elective spine surgical population.

Methods

A comprehensive literature search was performed using PubMed, Embase, and Cochrane databases to identify studies published after 2,000 that compared VTE chemoprophylaxis use in elective spine surgery. Studies involving patients aged < 18 years or with known trauma, cancer, or spinal cord injuries were excluded. Pooled incidence rates of VTE and SEH were calculated for all eligible studies, and meta-analyses were performed to assess the relationship between chemoprophylaxis and the incidences of VTE and SEH.

Results

Nineteen studies met our eligibility criteria, comprising a total of 220,932 patients. The overall pooled incidence of VTE was 3.2%, including 3.3% for DVT and 0.4% for PE. A comparison of VTE incidence between patients that did and did not receive chemoprophylaxis was not statistically significant (OR 0.97, p=.95, 95% CI 0.43-2.19). The overall pooled incidence of SEH was 0.4%, and there was also no significant difference between patients that did and did not receive chemoprophylaxis (OR 1.57, p=.06, 95% CI 0.99-2.50).

Conclusions

The use of perioperative chemoprophylaxis may not significantly alter rates of VTE or SEH in the elective spine surgery population. This review highlights the need for additional randomized controlled trials to better define the risks and benefits of specific chemoprophylactic protocols in various subpopulations of elective spine surgery.

Chemoprophylactic Anticoagulation After Spine Surgery Does Not Increase Epidural Hematoma Risk: A Propensity-matched Analysis

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

To calculate the magnitude of any increased risk of epidural hematoma (EDH) associated with chemoprophylactic anticoagulation (chemoprophylaxis), if any.

SUMMARY OF BACKGROUND DATA

Chemoprophylaxis for the prevention of venous thromboembolic events may be associated with an increased risk of EDH after spine surgery.

MATERIALS AND METHODS

A total of 6869 consecutive spine surgeries performed at our institution were identified, and clinical and demographic data were collected. We identified cases in which symptomatic EDHs were evacuated within 30 days postoperatively. Patients receiving chemoprophylaxis and controls were matched using K-nearest neighbor propensity score matching to calculate the effect of anticoagulation on the rate of postoperative EDH.

RESULTS

After propensity score matching, 1071 patients who received chemoprophylaxis were matched to 1585 controls. Propensity scores were well balanced between populations (Rubin B=20.6, Rubin R=1.05), and an 89.6% reduction in bias was achieved, with a remaining mean bias of 3.2%. The effect of chemoprophylaxis on EDH was insignificant ( P =0.294). Symptomatic EDH was independently associated with having a transfusion [odds ratio (OR)=7.30 (1.15, 46.20), P =0.035], having thoracic-level surgery [OR=41.19 (3.75, 452.4), P =0.002], and increasing body mass index [OR=1.44 (1.04, 1.98), P =0.028] but was not associated with chemoprophylaxis. Five out of 13 patients who developed EDH (38.5%) were receiving some form of anticoagulation, including 1 patient on therapeutic anticoagulation, 1 concurrently on aspirin and chemoprophylaxis, and 2 who were also found to have developed thrombocytopenia postoperatively. The median time on anticoagulation before EDH was 8.1 days. A higher proportion of patients who developed EDH also developed venous thromboembolic events than the general population [38.5% vs. 2.4%, OR=25.34 (9.226, 79.68), P <0.0001], and 1 EDH patient died from pulmonary embolism while off chemoprophylaxis.

CONCLUSIONS

Chemoprophylactic anticoagulation did not cause an increase in the rate of spinal EDH in our patient population.