Risk Factors of Pulmonary Embolism in Long-Segment Posterior Thoracolumbar Fusion: Scoring System for Prophylactic Inferior Vena Cava Filter Placement

Objective: To investigate the factors for pulmonary embolism (PE) development and the necessity of inferior vena cava (IVC) filter placement. Specifically, propose a scoring system to identify patient populations who benefit from IVC filter placement. Methods: A single-institution retrospective cohort study was performed between 2010 and 2022. Inclusion criteria were open posterior thoracolumbar fusion, ≥7 segments, and adult patients ≥18 years old. Patients undergoing any surgical approach other than posterior were excluded. Risk factors such as smoking status, illicit drug use/type, body mass index, gender, age, anticoagulation history, and status on the presence of PE were reviewed. Results: A total of 365 patients were identified; 170 patients (46.6%) were male, and 195 (53.4%) were female. Twenty-four patients (6.6%) had IVC filters placed before the surgery. The overall rate of PE was 8 (2.2%), all in patients without IVC filter. Analysis showed that gender, age, and body mass index did not affect the incidence of PE. Smoking status, history of illicit drug use (cocaine/cannabis), and history of deep vein thrombosis/PE significantly increased the incidence of PE. Based on multivariate logistic regression, we developed a scoring system composed of the significant risk factors outlined earlier to determine the risk of developing PE. Our scoring system stratified risk to low risk (0–3 points), medium risk (4–6 points), and high risk (7 or 8 points). Conclusions: The risk of PE is relatively low after long-segment posterior thoracolumbar fusion. Smoking (former and current), history of cocaine/cannabis use, and history of venous thromboembolism are risk factors in such patients. We recommend prophylactic IVC filter use only in high-risk subgroups and under discretion between physician and patient in medium-risk subgroups.