Blood Transfusion Rates and Predictive Factors in Posterior-Based Minimally Invasive Scoliosis Surgery for Idiopathic Scoliosis: A LASSO-Based Prediction Model

Study Design Retrospective cohort study. Objectives To investigate blood transfusion rates in posterior-based minimally invasive scoliosis surgery (MISS) for idiopathic scoliosis (IS) and to develop a prediction model for perioperative blood transfusion. Methods We retrospectively reviewed data of 751 patients with IS who underwent posterior-based MISS between 2015 and 2026. The Least Absolute Shrinkage and Selection Operator (LASSO) regression model was applied to identify predictors of transfusion among demographics, perioperative metrics, radiographic measurements, and transfusion-related profiles. The model was constructed by development cohort March 2015 and February 2024 (development cohort, n = 595) and validated using the temporal data between March 2024 and February 2026 (validation cohort, n = 156). Results In the total cohort, 518 patients (69.0%) required a blood transfusion. Among them, 76 patients received only postoperative transfusions, with the majority administered within 3 days postoperatively. Post-LASSO multivariate regression analysis demonstrated that greater estimated blood loss, lower preoperative hemoglobin (Hb) levels, absence of tranexamic acid use, longer fusion levels, and a larger major preoperative Cobb angle were independently associated with perioperative transfusion. The perioperative model demonstrated good discrimination, with an area under the receiver operating characteristic curve of 0.89 in the development cohort and 0.94 in the validation cohort. Conclusions Postoperative transfusion was uncommon, and transfusion-free surgery may be feasible in selected lower-risk patients undergoing posterior-based MISS for IS. Based on our prediction model, strategies for blood transfusion-free surgery should be individualized, considering patient-specific profiles such as preoperative Hb levels, fusion level, and Cobb angle.