1422 www.spinejournal.com September 2015 DEFORMITY SPINE Volume 40, Number 18, pp 1422-1430 ©2015, Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/BRS.0000000000001019 Study Design. Retrospective cohort study. Objective. To determine predictors of and 30-day complications associated with blood transfusion volume after posterior spinal fusion for adolescent idiopathic scoliosis (AIS). Summary of Background Data. Posterior arthrodesis is a common procedure performed for AIS, and patients frequently require perioperative blood transfusions. Few studies, however, have examined the rates and potential complications associated with blood transfusion volume. Methods. Patients undergoing posterior arthrodesis for AIS were selected from the National Surgical Quality Improvement Program pediatric database from 2012 to 2013. Patients were stratified on the basis of blood transfusion volume and patient demographics and comorbidities, operative characteristics, and 30-day complications were recorded. Multivariate analyses were performed to determine predictors of transfusion as well as the effect of transfusion volume on 30-day complication rates. Results. A total of 1691 patients were included. Male sex ( P = 0.010), esophageal or gastrointestinal disease ( P = 0.016), cardiac risk factors ( P = 0.037), preoperative inotrope requirement ( P = 0.031), total operative time of 300 minutes or more ( P < 0.001), and posterior arthrodesis of 13 or more vertebral segments ( P < 0.001) were independent risk factors for requiring blood transfusion. Total transfusion volume of 20 mL/kg or more was the minimum volume independently associated with increased rates of total complications ( P = 0.018), with a complication rate of 5.9%. Conclusion. We present the first large, comprehensive analysis of complications related to blood transfusion events and transfusion volume on short-term postoperative complications after posterior From the *Center for Children, NYU Hospital for Joint Diseases, New York, NY; and †Northwestern University Feinberg School of Medicine, Chicago, IL. Acknowledgment date: January 19, 2015. Revision date: April 3, 2015. Acceptance date: June 3, 2015. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No relevant financial activities outside the submitted work. Address correspondence and reprint requests to Shobhit V. Minhas, BA, Northwestern University Feinberg School of Medicine, 441 East Erie St, Apt 2713, Chicago, IL 60611; E-mail: shobhitvishnoi2@gmail.com A dolescent idiopathic scoliosis (AIS) is a common struc- tural coronal deformity of the spine, affecting up to 3% of the at-risk pediatric population. 1–3 Although nonoperative treatment can be employed to prevent curve progression in certain situations, surgical intervention is often necessary for correction and maintenance in cases of severe disease. 4,5 These procedures are frequently complex, lengthy, and involve extensive soft-tissue exposure, placing patients at significant risk for blood transfusions. 6–9 Allogeneic transfusions are associated with an increased risk of surgical site and systemic infection, transmission of infectious agents, acute hemolytic reactions, and transfusion- related immune modulation. 10–13 Moreover, both autologous and allogeneic transfusions contribute to longer hospital stay and, consequently, increased hospital costs. 14,15 To decrease the likelihood of transfusion, surgeons employ a number of blood conserving strategies. These include tranexamic acid, cell salvage, and preoperative autologous blood donation, contributing to an overall reduction in blood loss and need for allogeneic transfusions after AIS surgery. 16–21 Transfusion of 25 mL/kg of red blood cells (RBCs) over a 24-hour period is widely accepted as a significant safety threshold and a marker of a “large volume transfusion” in pediatric medicine due to concern for potential metabolic, cardiovascular, and coagulopathic derangements after an excess of this volume. 22,23 Despite the prevalence of and pre- cautions taken after blood transfusions, there is a paucity of literature regarding blood transfusions with respect to AIS surgery. 8,9,24–28 Although these studies examined perioperative predictors of blood loss and transfusion requirement, they were limited to smaller, single-institutional cohorts with no data regarding transfusion volumes (TTVs) and their effect on subsequent surgical outcomes. The aims of our study are arthrodesis for AIS. Although transfusion in general is not associated with 30-day adverse events, a volume of 20 mL/kg was associated with higher complication rates. Key words: blood, transfusion, posterior, arthrodesis, spine, scoliosis, NSQIP, complications, fusion, AIS, mortality, pediatric. Level of Evidence: 4 Spine 2015;40:1422–1430 Assessing the Rates, Predictors, and Complications of Blood Transfusion Volume in Posterior Arthrodesis for Adolescent Idiopathic Scoliosis Shobhit V. Minhas, MD,* Ian Chow, BA,† Joseph Bosco, MD,* and Norman Y. Otsuka, MD* Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. SPINE150189_LR 1422 SPINE150189_LR 1422 17/08/15 2:06 PM 17/08/15 2:06 PM