Intraoperative Blood Loss in Lumbar Posterior Spinal Fusion for Degenerative Disorders: Prevalence, Risk Factors, and Associations with Perioperative Complications and Recovery Outcomes — A Retrospective Cross-sectional Study

Abstract

Background: Intraoperative blood loss (IOBL) remains a critical challenge in posterior spinal fusion (PSF) for degenerative lumbar disorders, influencing perioperative complications and long-term outcomes. Objectives: This study evaluated the prevalence of massive IOBL and its associations with patient prognosis in a single-center retrospective sample. Methods: In this retrospective cross-sectional study, 63 adult patients (aged 30 - 60 years) undergoing elective primary PSF at L3 - L5 levels (March 2022 - March 2023) were analyzed. Massive IOBL was defined as ≥ 30% of estimated blood volume (Nadler formula). Data on demographics, surgical factors, complications (Clavien-Dindo graded), transfusion needs, length of stay, and functional recovery (NRS pain, return to activities/work) were extracted from records and telephone follow-up (85% response). Associations were assessed using chi-square tests for categorical variables and Kendall's tau for continuous variables (SPSS v26; P < 0.05). Results: Massive IOBL occurred in 30.2% of cases and was significantly associated with two-level fusion (43.2% vs. 11.5%; P = 0.007) and intraoperative transfusion (67.9% vs. 0.0%; P < 0.001). It correlated with higher cardiac (100.0% vs. 0.0%; P < 0.001), renal (71.4% vs. 28.6%; P = 0.012), hematologic (85.7% vs. 14.3%; P < 0.001), and mortality (100.0% vs. 0.0%; P = 0.029) risks, but not with sex (P = 0.759), neurological (P = 0.816), or infectious (P = 0.790) complications. Continuous correlations included reduced postoperative hemoglobin (τ = -0.383; P < 0.001), prolonged operative duration (τ = 0.316; P = 0.003), increased transfusion units (τ = 0.397; P = 0.039), extended ICU stay (τ = 0.618; P < 0.001), delayed return to activities/work (τ = 0.465/0.397; both P < 0.001), and higher 30-day pain (τ = 0.384; P < 0.001). Conclusion: In the present study, massive intraoperative blood loss was associated with multilevel fusion, transfusion requirements, and higher rates of certain perioperative complications and delayed recovery outcomes. These preliminary associations are limited by sample size and design; further prospective studies are warranted to confirm and explore potential interventions.