Predictive factors for intraoperative blood loss in surgery for adolescent idiopathic scoliosis

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is a common spinal deformity. Posterior spinal fusion remains an important surgical treatment for AIS. This study aims to determine the predictive factors for intraoperative blood loss in AIS surgery. METHODS: Patients who had undergone posterior spinal fusion for adolescent idiopathic scoliosis in a single university hospital were reviewed over a 7-year period. Predictive factors for intra-operative blood loss were studied by multivariate analysis to derive a regression model. Receiver operating characteristic analysis was performed to determine the cut-off values of factors contributing to significant intraoperative blood loss (≥500 ml). RESULTS: Two hundred and twelve patients were included. Intraoperative blood loss was found to be correlated with gender (r(s) = 0.30 (0.17–0.43)), preoperative hemoglobin level (r(s) = 0.20 (0.04–0.31)), preoperative Cobb angle (r(s) = 0.20 (0.02–0.29)), number of fused levels (r(s) = 0.46 (0.34–0.58)), operation duration (r(s) = 0.65 (0.54–0.75)), number of anchors (r(s) = 0.47 (0.35–0.59)), and p-value ranged from < 0.001 to < 0.05. Significant intraoperative blood loss was influenced by the male gender, operation duration greater than 257.5 min and more than 10 anchors used. CONCLUSIONS: Male gender, increased operation duration and higher number of anchors predicted higher intra-operative blood loss.