Introduction

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), is a life-threatening complication that can occur after major surgery. Despite increasing rates of spinal fusions nationally, the optimal timing and efficacy of VTE chemoprophylaxis remain unknown, and chemoprophylaxis comes with the risk of bleeding, epidural hematoma, and possible reoperation. The current literature is limited by heterogeneous patient populations, surgical techniques, and inconsistent timing and dose of chemoprophylaxis^1,2. We therefore sought to synthesize the available evidence and construct a clinical decision tree model to better guide clinicians in the use of VTE prophylaxis following spinal fusion.

Methods

We constructed a decision analytic model representing potential outcomes after spinal fusions with and without VTE prophylaxis. Probabilities of outcomes (epidural hematoma, VTE event) were derived from a systematic review of randomized trials and observational studies. Five reviewers independently screened abstracts and full texts, with data extracted to derive probabilities and health utility values. A clinical decision tree was constructed using the weighted averages of each outcome probability and utility values among the studies collected. Weighted probabilities and utility values were combined to conduct a rollback analysis and subsequent sensitivity analysis to determine the strength of utilities.

Results

A total of 8 studies with 2,177 patients were included in the final analysis. The base-case analysis demonstrated that VTE Chemoprophylaxis yielded an expected utility of 0.79 compared to 0.89 for No VTE Chemoprophylaxis. Results from one-way sensitivity analyses indicated that the model conclusions were robust to plausible variations in key parameters, including utility values and probabilities associated with VTE and epidural hematoma events. Across tested ranges, the expected utility values varied minimally (range: 0.85-.94 for No VTE Chemoprophylaxis; 0.75-0.84 for VTE Chemoprophylaxis), and No VTE Chemoprophylaxis remained the preferred option at all threshold changes for both utility values and probabilities.

Conclusions

Similar to the current literature regarding VTE Chemoprophylaxis in spinal fusion surgery, our findings support that using VTE Chemoprophylaxis is not beneficial for the prevention of VTE and other bleeding complications in spinal fusion surgery.

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