Background and Goal of Study: Scoliosis is a three-dimensional deformity of the spine. Adolescent idiopathic scoliosis (AIS) is the most common type (1-3%). Surgical treatment involves exposure of a vast area of decorticated, raw and cancellous bone. Decreasing blood loss and transfusion requirements should improve patient’s safety and their post-operative recovery. Tranexamic acid (TXA) is recommended to reduce blood loss especially in cardiac surgery. The aim of this study was to assess the effect of TXA on blood loss and transfusion requirements in posterior arthrodesis in AIS.  
Materials and Methods: Retrospective cross section study of all patients with AIS that had undergone posterior arthrodesis. All perioperative records from January 2009 to December 2014 were reviewed. Patients over 21y, with other diagnosis and combined anterior/posterior spinal fusion were excluded. Blood loss was assessed by measuring suction content and weighing swabs at the end of surgery. We had two groups: TXA group and non-TXA group (NTXA). In the TXA group patients received a loading dose of 10 mg/kg TXA, followed by an infusion of 1 mg/kg/h. Absolute and relative frequencies were calculated for categorical variables, and mean and standard deviation were calculated for quantitative variables. Proportions were compared using chi-squared test (or Fisher’s test, as adequate) while student’s t-test and Mann-Whitney test were used to compare continuous variables. Statistical analyses were performed using Stata14. Significance level was set at 0.05. 
Results and Discussion: 220 posterior arthrodesis for AIS were analysed. Of these, 21 were excluded (missing information about blood loss, administration of TXA, over 21y). There was no significant difference in demographic data and Cobb angle in the 2 groups. The TXA group had a greater number of screws (p<0.001); there was no significant difference in the number of levels fused and duration of surgery. Intraoperative blood loss was 1649ml in NTXA group (95% CI: 1455-1843) and 1028ml in TXA group (95% CI: 881-1175); The number of patients transfused intraoperatively was significantly lower in the TXA group (n=12 vs n=69; p<0.001); in the postoperative period, there was no significant difference between the groups. No adverse events or TXA reactions were reported. 
Conclusion: The TXA dose used in this retrospective analysis reduced perioperative blood loss and transfusion requirement in intraoperative in patients undergoing posterior arthrodesis for AIS.


07 / Tranexamic acid reduces blood loss and transfusion requirements in adolescent idiopathic scoliosis