Predictors of perioperative blood loss in primary posterior hemivertebra resection for pediatric patients with congenital scoliosis.

Several studies have elucidated the risk factors of intraoperative bleeding. However, the total blood loss (visible and hidden loss) and related risk factors were seldom reported. In this study, we aimed to identify predictors of massive blood loss in posterior hemivertebra resection for pediatric patients. Clinical records were retrospectively reviewed for 108 pediatric patients who underwent primary posterior hemivertebra resection and spinal fusion for congenital scoliosis from June 2017 to June 2019. Intraoperative blood loss was recorded and hidden blood loss was calculated by deducting the intraoperative loss from the total blood loss calculated using specific formula. Perioperative information was collected for multivariable linear regression analysis to determine the independent risk factors of the blood loss. The mean total blood loss was 575.0 ± 318.0 ml during the perioperative period, accounting for 42.1% of the estimated blood volume. The intraoperative and hidden loss were 337.6 ± 179.5 ml and 237.4 ± 204.8 ml, respectively, accounting for 58.7 and 41.3% of the total loss. Multivariable linear regression indicated that age, preoperative Cobb angle, operative time, and number of fused levels were independent risk factors of the total blood loss. Patients with operative time ≥145 minutes, fused levels ≥4, and preoperative Cobb angle ≥40° have an increased risk of massive blood loss. The perioperative blood loss of surgery for congenital scoliosis was considerable, with a high percentage of hidden blood loss. Patients with severe deformity, more fused levels, and longer operative time had higher risk of massive blood loss.