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.