The Impact of Hemoglobin on Outcomes in Multi-Level Spinal Fusion for Adult Degenerative Scoliosis

Introduction: Significant perioperative change in hemoglobin (dHgb) is an established predictor of worsened long-term outcomes following adult degenerative scoliosis (ADS) surgery. This study evaluates how dHgb predicts outcomes in multi-level spine fusion and factors that may reduce dHgb.

Methods: Patients who underwent long-segment thoracolumbar fusion (≥4 levels) for spinal deformity from 2016-2020 at our institution were included. Hemoglobin (Hgb) values within two weeks before and directly after surgery were used to calculate dHgb. A linear regression model assessed relationships between pre- and perioperative factors and outcomes in patients with ADS undergoing spinal fusion.

Results: 235 consecutive patients who underwent spinal fusion were included, of whom 80 were male and 155 female. Average dHgb was -3.45±2.25 in men and -3.13±1.86 in women (p=0.107). Low preoperative Hgb was associated with increased hospital length of stay (LOS) (Coefficient: -0.374, 95%CI: -0.667, -0.082, p=0.024) and intensive care unit (ICU) LOS (Coefficient: -6.97, 95%CI: -12.6, -1.32, p=0.017) in women, but not men (p=0.76 and p=0.82, respectively). A lower dHgb was associated with significantly reduced Oswestry Disability Index (ODI) scores following surgery in men (Coefficient: -2.51, 95%CI: -4.40, -0.61, p=0.012), but not women (p=0.14). Transfusion of fresh frozen plasma (FFP) was associated with improved dHgb in both men and women (p=0.024 and p< 0.005, respectively), while packed red blood cells were associated with improved dHgb in women but not men (p < 0.005 and p=0.13, respectively). Cryoprecipitate improved dHgb in men only (p=0.012).

Conclusion : Surgeons should consider delaying surgery in women with ADS until preoperative Hgb reaches higher values as decreased values may confer prolonged ICU and total LOS.