OBJECTIVE: To (1) report the incidence of overall infection after surgery, (2) assess if allogenic red blood cell (RBC) transfusion and other clinical factors increase infection risk, and (3) explore if a safe transfusion dose exists.
SUMMARY OF BACKGROUND DATA: Open spinal metastasis surgery can involve significant blood loss and subsequent transfusion use. Although transfusion has been linked with increased infection rates in other settings, evidence within spinal metastasis surgery is limited.
METHODS: Adults with spinal metastasis undergoing open decompressive or stabilization surgery between 2017 and 2022 were included. The primary outcome was overall infection occurring within 30 days postoperatively. Multivariable logistic regression assessed transfusion and other risk factors for infection. Additional confounders (anemia, operative time, hospital stay, blood loss) were included in a sensitivity analysis.
RESULTS: Among 796 patients (mean age 62±12 y, 41% female), 127 (16%) developed infections. Transfusion was given in 329 (41%) of patients and was independently associated with increased risk of overall infection postoperatively (OR 2.28, P<0.001), which persisted in sensitivity analysis (P<0.012). A dose-dependent association was observed (250 mL increase: OR 1.10, P=0.014) without safe threshold (1-unit: OR 2.11, P=0.030). Higher BMI, COPD, elevated white blood cell count, fast-growing primary tumor, ≥3 spinal metastases, ≥4 levels operated, low serum albumin, and preoperative chemo-, immuno- or targeted therapy were also associated with infection (P<0.05).
CONCLUSION: Open spinal metastasis surgery carries high risk of both RBC transfusion and infection. Transfusion increased risk of infection in a dose-dependent manner. No safe volume threshold was identified in this cohort. Although often unavoidable, surgeons should strive for restrictive transfusion strategies and optimize perioperative protocols to reduce transfusion requirements. Higher comorbidity-, tumor-, and surgical burden further increased infection risk. These factors may aid in risk stratification and balancing the need for transfusion accordingly. Additionally, surgeons might optimize infection risk by favoring less invasive procedures over extensive (blood loss-prone) surgery and considering nutritional optimization (BMI, albumin levels).
STUDY DESIGN: Multi-institutional retrospective cohort study in the United States and United Kingdom.
LEVEL OF EVIDENCE: III.
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