Risk of Venous Thromboembolism After Lumbar Spine Interbody Fusion: A Propensity-Matched Cohort Study

INTRODUCTION: Venous thromboembolism (VTE) is a feared complication after spine surgery, with limited data comparing approach-specific risk factors after lumbar interbody fusion. This study compared the rate of VTE complications after transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF). METHODS: A multi-institutional electronic medical record database was queried for patients aged older than 18 years undergoing single-level or multilevel TLIF and ALIF between 2004 and 2024. Patients were evenly divided into single-level (n = 9,618) and multilevel (n = 1,774) TLIF and ALIF cohorts. Propensity score matching (1:1) was conducted using demographics, comorbidities, and anticoagulation use. Odds ratios (95% confidence intervals) of VTE and postoperative bleeding complications were calculated at 30, 60, and 90 days. RESULTS: Compared with single-level TLIF, single-level ALIF was associated with higher odds of VTE events at 30 days (OR: 2.0, 95% CI, 1.4 to 2.9; P < 0.001), 60 days (OR: 1.8, 95% CI, 1.3 to 2.5; P < 0.001), and 90 days (OR: 1.7, 95% CI, 1.3 to 2.4; P < 0.001). Multilevel ALIF was also associated with higher odds of VTE events at 30 days (OR: 2.7, 95% CI: 1.2 to 5.1; P = 0.015), 60 days (OR: 2.0, 95% CI, 1.2 to 3.4; P = 0.010), and 90 days (OR: 1.9, 95% CI, 1.1 to 3.2; P = 0.015) when compared with multilevel TLIF. No significant differences were observed in postoperative bleeding complications between single-level and multilevel TLIF and ALIF cohorts at all study intervals (P > 0.05). DISCUSSION: ALIF was associated with increased VTE complications, with no differences in postoperative bleeding complications when compared with TLIF. These findings suggest that surgical approach should be considered in perioperative VTE risk stratification and patient counseling after lumbar interbody fusion surgery, highlighting the need for future prospective studies evaluating approach-specific VTE prevention strategies.