Correlation between perioperative total blood loss and paraspinal muscle metrics in patients undergoing single-level transforaminal lumbar interbody fusion

Abstract Background Research on blood loss after transforaminal lumbar interbody fusion (TLIF) is of great significance for peri‑operative management and postoperative rehabilitation. Most previous studies primarily focused on hidden blood loss and conventional clinical risk factors, while only limited paraspinal muscle parameters have been adopted for bleeding risk evaluation. The present study aimed to assess the relationship between paraspinal muscle metrics and perioperative total blood loss (TBL) in patients who underwent single-level TLIF. Methods This retrospective single-center study included patients who underwent single-level TLIF between 2023 and 2025 in our institution. Demographic, perioperative, hematological, and coagulation data were collected. Preoperative lumbar magnetic resonance imaging (MRI) was used to evaluate paraspinal muscle parameters. These parameters included total cross-sectional area (TCSA), functional cross-sectional area (fCSA), fat infiltration (FI), and mean signal intensity. TBL was calculated using established formulas. Correlation analyses were performed to screen relevant indicators preliminarily, and multivariable linear regression analyses were further conducted to identify independent predictors of TBL. Results A total of 170 patients (69 males and 101 females) were included in this study. Correlation analyses showed significant relationships between several paraspinal muscle parameters and TBL ( P < 0.05). TCSA and fCSA were positively correlated with TBL, while FI and mean signal intensity were negatively correlated. Multivariable regression identified L3 ES-TCSA as independent positive predictor, and L4 MF-FI as independent negative predictor of TBL (all P < 0.05). The regression model had a good predictive performance (R² = 0.571, P < 0.05). Conclusion Paraspinal muscle related parameters were significantly associated with TBL in patients who underwent single-level TLIF. Incorporating paraspinal muscle characteristics into routine preoperative assessment may enhance bleeding risk stratification and support individualized perioperative management.