Impact of Prolonged Operative Duration on Postoperative Symptomatic Venous Thromboembolic Events After Thoracolumbar Spine Surgery.

OBJECTIVE: To determine the effect of operative duration on the rate of postoperative symptomatic venous thromboembolic (VTE) events in patients undergoing thoracolumbar spine fusion. METHODS: We identified all thoracolumbar spine fusion patients between 2012 and 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 postoperative 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 1108 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 (odds ratio: 1.003, 95% confidence interval: 1.001-1.01, P = 0.021). For each additional hour of operative duration, the risk of VTE increased by 18%. A cutoff time of 218 minutes was identified (area under the curve [95% confidence interval] = 0.622 [0.533-0.712]) as an optimal predictor of increased risk for a VTE event. CONCLUSIONS: 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.

Demographics and Medical Comorbidities as Risk Factors for Increased Episode of Care Costs Following Lumbar Fusion in Medicare Patients.

The objective was to evaluate medical comorbidities and surgical variables as independent risk factors for increased health care costs in Medicare patients undergoing lumbar fusion. Care episodes limited to lumbar fusions were retrospectively reviewed on the Centers of Medicare and Medicaid Innovation (CMMI) Bundled Payment for Care Improvement (BPCI) reimbursement database at a single academic institution. Total episode of care cost was also collected. A multivariable linear regression model was developed to identify independent risk factors for increased total episode of care cost, and logistic models for surgical complications and readmission. A total of 500 Medicare patients were included. Risk factors associated with increased total episode of care cost included transforaminal interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) (ß = $5,399, P < 0.001) and ALIF+PLF (AP) fusions (ß = $24,488, P < 0.001), levels fused (ß = $3,989, P < 0.001), congestive heart failure (ß = $6,161, P = 0.022), hypertension with end-organ damage (ß = $10,138, P < 0.001), liver disease (ß = $16,682, P < 0.001), inpatient complications (ß = $4,548, P = 0.001), 90-day complications (ß = $10,012, P = 0.001), and 90-day readmissions (ß = $15,677, P < 0.001). The most common surgical complication was postoperative anemia, which was associated with significantly increased costs (ß = $18,478, P < 0.001). Female sex (OR = 2.27, P = 0.001), AP fusion (OR = 2.59, P = 0.002), levels fused (OR = 1.45, P = 0.005), cerebrovascular disease (OR = 4.19, P = 0.003), cardiac arrhythmias (OR = 2.32, P = 0.002), and fluid electrolyte disorders (OR = 4.24, P = 0.002) were independent predictors of surgical complications. Body mass index (OR = 1.07, P = 0.029) and AP fusions (OR = 2.87, P = 0.049) were independent predictors of surgical readmission. Among medical comorbidities, congestive heart failure, hypertension with end-organ damage, and liver disease were independently associated with a significant increase in total episode of care cost. Interbody devices were associated with increased admission cost.