The incidence and risk factors for perioperative allogeneic blood transfusion in primary idiopathic scoliosis surgery

Study design: Case–control study. Objectives: Evaluate the rate and risk factors for perioperative allogeneic blood transfusion (ABT) in primary idiopathic scoliosis surgery at a single institution. Summary of background data: Avoiding perioperative ABT is ideal as transfusions are associated with adverse reactions, increased rates of infection, prolonged hospitalization, additional laboratory testing, and increased cost. Risk factors identified in other studies have differed, and to our knowledge, few studies have identified clinical strategies to predict patients at high risk for ABT. Methods: We reviewed 402 idiopathic scoliosis patients who underwent primary posterior spinal fusion and instrumentation (PSFI) at a single institution from 2015 to 2017. Medical records and radiographs were reviewed for all patients. Transfused patients were compared to the remaining cohort to find significant differences and identify predictors of higher ABT risk. Results: ABT occurred in 73 patients (18.2%), with the majority of transfusions occurring intraoperatively (41%) or postoperatively on the day of surgery (25%). The seven surgeons involved varied significantly in incidence of ABT (2.4–35.8%, p = 0.002). Patients who had ABT were younger (13.3 vs. 14.1 years, p < 0.01), had lower BMI (48th vs. 61st percentile, p < 0.001), and lower preoperative hemoglobin (13.1 vs. 13.7 g/dL, p < 0.01). Greater preoperative major Cobb angle (69° vs. 61.5°, p < 0.001), number of fusion levels (11.8 vs. 10.3, p < 0.001), and estimated blood loss (770 vs. 448 mL, p < 0.001) also predicted ABT. Conclusions: ABT was associated with several risk factors, five of which are known preoperatively. Surgeons can use knowledge of these risk factors to assess transfusion risk preoperatively and plan surgery, blood management, and laboratory testing accordingly. The development of best practices for ordering ABT is possible given the variation amongst providers. Level of evidence: Level III.