Risk Factors for Blood Transfusion With Primary Posterior Lumbar Fusion

Study Design. Retrospective cohort study. Objective. To identify factors associated with blood transfusion for primary posterior lumbar fusion surgery, and to identify associations between blood transfusion and other postoperative complications. Summary of Background Data. Blood transfusion is a relatively common occurrence for patients undergoing primary posterior lumbar fusion. There is limited information available describing which patients are at increased risk for blood transfusion, and the relationship between blood transfusion and short-term postoperative outcomes is poorly characterized. Methods. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was used to identify patients undergoing primary posterior lumbar fusion from 2011 to 2013. Multivariate analysis was used to find associations between patient characteristics and blood transfusion, along with associations between blood transfusion and postoperative outcomes. Results. Out of 4223 patients, 704 (16.7%) had a blood transfusion. Age 60 to 69 (relative risk [RR] 1.6), age greater than equal to 70 (RR 1.7), American Society of Anesthesiologists class greater than equal to 3 (RR 1.1), female sex (RR 1.1), pulmonary disease (RR 1.2), preoperative hematocrit less than 36.0 (RR 2.0), operative time greater than equal to 310 minutes (RR 2.9), 2 levels (RR 1.6), and 3 or more levels (RR 2.1) were independently associated with blood transfusion. Interbody fusion (RR 0.9) was associated with decreased rates of blood transfusion. Receiving a blood transfusion was significantly associated with any complication (RR 1.7), sepsis (RR 2.6), return to the operating room (RR 1.7), deep surgical site infection (RR 2.6), and pulmonary embolism (RR 5.1). Blood transfusion was also associated with an increase in postoperative length of stay of 1.4 days (P < 0.001). Conclusion. 1 in 6 patients received a blood transfusion while undergoing primary posterior lumbar fusion, and risk factors for these occurrences were characterized. Strategies to minimize blood loss might be considered in these patients to avoid the associated complications. Level of Evidence: 3