Hidden Blood Loss in Adolescent Idiopathic Scoliosis Patients Undergoing Posterior Spinal Fusion Surgery: A Retrospective Study of 765 Cases in a Single Center

Abstract

\n Purpose: To investigate Hidden blood loss (HBL) and its potential risk factors in adolescent idiopathic scoliosis patients undergoing posterior spinal fusion surgery and elucidate the influence of HBL on postoperative blood transfusion. Methods: We retrospectively studied 765 patients undergoing posterior spine fusion for adolescent idiopathic scoliosis from January 2014 to December 2018. The patient’s demographics, blood loss related parameters, operation and blood loss information were extracted. The association between patient’s characteristics and HBL was analyzed by Pearson or Spearman correlation analysis. Multivariate linear regression analysis was used to determine independent risk factors associated with HBL. Binary logistic regression analysis was used to analyze the influence of HBL on postoperative blood transfusion.Results: A total of 765 patients including 128 males and 637 females (age range 10-18 years) were included in this study. The mean amount of HBL was 693.5±473.4 ml, accounting for 53.9% of the total blood loss. In multivariate linear regression analysis, we found that preoperative Hct (p=0.003) and allogeneic blood transfusion (p<0.0001) were independent risk factors for HBL, while tranexamic acid (p=0.003) was negatively related to HBL. Binary logistic regression analysis showed that HBL > 850 ml ( P < 0.001, OR: 8.845, 95%CI: 5.806-13.290) was the independent risk factor for postoperative blood transfusion.Conclusion: a large amount of HBL was incurred in adolescent idiopathic scoliosis patients undergoing posterior spinal fusion surgeries. Allogeneic blood transfusion and preoperative Hct were independent risk factors for HBL, while tranexamic acid was negatively related to HBL. HBL and its influential factors should be taken into account when considering the perioperative transfusion management. These patients with HBL greater than 850 ml should be paid more attention in case of postoperative anemia.Level of evidence: Level III