A Comparative Analysis of 4-, 12-, and 24-hour Intervals of Drain Clamping Reduces Postoperative Blood Loss Following Posterior Spinal Surgery in Adolescent Idiopathic Scoliosis: A Prospective Randomized Controlled Trial

Abstract The study was designed as a prospective randomized controlled trial. Posterior spinal fusion for adolescent idiopathic scoliosis (AIS) is frequently associated with substantial blood loss, often requiring blood transfusion. To reduce postoperative blood loss, drain clamping is considered a viable technique to enhance hemostasis; however, the optimal time intervals for applying postoperative drain clamping remain uncertain. The aim of the study is to analyze and compare the volume of postoperative blood loss following 4-, 12-, and 24-hour drain clamping intervals in AIS patients undergoing posterior spinal fusion. Patients diagnosed with AIS who underwent posterior spinal surgery between 2021 and 2024 were recruited for the study. The patients were allocated in a 1:1:1 ratio to 4-, 12-, or 24-hour intervals of drain clamping. The primary outcome was cumulative drain output until removal. Secondary outcomes included intraoperative blood loss, blood loss per fused level, transfusion rate, postoperative change in hemoglobin, Cobb angle correction, and complications. Analyses followed the intention-to-treat principle. Ninety patients were enrolled in this study. Mean cumulative drain output was 1,374 ± 339.8 mL in the 4-hour interval group, 1,325 ± 467.6 mL in the 12-hour interval group, and 1,472 ± 286.3 mL in the 24-hour interval group (p = 0.30). Intraoperative blood loss (p = 0.47), blood loss per fused level (p = 0.54), and transfusion rates (p = 0.63) were comparable. No hematomas, surgical site infections, or delayed wound healing were observed up to 24 months. Minor complications included one case of adhesive bandage irritation (12-hour interval group) and two cases of superficial wound dehiscence (24-hour interval group). Drain clamping at 4-, 12-, or 24-hour intervals did not significantly alter postoperative blood loss or transfusion requirements. A 4-hour interval drain clamping appears sufficient, balancing hemostatic benefit with safety.