Objective:

To determine the effect of operative duration on the rate of post-operative symptomatic venous thromboembolic (VTE) events in patients undergoing thoracolumbar spine fusion.

Methods:

We identified all thoracolumbar spine fusion patients between 2012-2021. Operative duration was defined as time from skin incision to skin closure. A 1:1 propensity match was conducted incorporating patient and surgical characteristics. Logistic regression was performed to assess predictors of post-operative symptomatic VTE events. A receiver operating characteristic curve was created to determine a cutoff time for increased likelihood of VTE.

Results:

We identified 101 patients with VTE and 1,108 patients without VTE. Seventy-five patients with VTE were matched to 75 patients without VTE. Operative duration (339 vs. 262 minutes, p=0.010) and length of stay (5.00 vs. 3.54 days, p=0.008) were significantly longer in patients with a VTE event. Operative duration was an independent predictor of VTE on multivariate regression (OR: 1.003, 95% CI: 1.001 – 1.01, p=0.003). For each additional hour of operative duration, the risk of VTE increased by 18%. A cutoff time of 218 mins was identified (AUC [95% CI] = 0.622 [0.533 – 0.712]) as an optimal predictor of increased risk for a VTE event.

Conclusion:

Operative duration significantly predicted symptomatic VTE, especially after surgical time cutoff of 218 minutes. Each additional hour of operative duration was found to increase VTE risk by 18%. We also identify the impact of VTE on 90-day readmission rates suggesting significantly higher costs and opportunity for hospital acquired conditions, in line with prior literature.