Does patient diagnosis predict blood loss during posterior spinal fusion in children?

STUDY DESIGN.: A retrospective review. OBJECTIVE.: To assess the relationship between diagnosis and blood loss in children undergoing posterior spinal fusion surgery for deformity correction. SUMMARY OF BACKGROUND DATA.: To our knowledge, this relationship is not well established. It has important implications for understanding the mechanisms for blood loss and planning for surgery. METHODS.: Clinical records were reviewed for all patients 10 to 18 years of age who underwent spinal fusion surgery (at least 5 levels) by the senior author from 2001 through 2011. Patients were excluded for antifibrinolytic use, vertebral column resections, history of spinal surgery, nonpedicle screw instrumentation, cervical spine fusion, or anterior approaches. The 617 patients (with 37 diagnoses) were categorized into 5 groups: idiopathic scoliosis (IS), Scheuermann kyphosis (SK), cerebral palsy, other neuromuscular disorders, and genetic and syndromic disorders. Analysis of covariance was used to assess differences in blood loss across the diagnostic groups. Normalized blood loss (NBL) was calculated by dividing blood loss by number of levels fused and by patient's weight; NBL differences between groups were analyzed using Bonferroni correction method. Significance was set at P < 0.05. RESULTS.: Blood loss differed significantly by diagnostic group, adjusting for extent of fusion and patient weight (P < 0.001). Patients with cerebral palsy had a significantly higher NBL than patients with IS (P < 0.001), SK (P < 0.001), other neuromuscular disorders (P = 0.049), or genetic and syndromic disorders (P = 0.006). Patients with other neuromuscular disorders had a significantly higher NBL than patients with IS (P < 0.001) or SK (P < 0.001). Patients with genetic and syndromic disorders also had a significantly higher NBL than patients with IS (P < 0.001) or SK (P < 0.001). CONCLUSION.: There is a significant relationship between patient diagnosis and blood loss during posterior spinal fusion surgery in children.