Risk Factor Analysis of Hidden Blood Loss in Unilateral Biportal Endoscopy for Degenerative Lumbar Diseases

Background To explore the risk factors associated with hidden blood loss (HBL) during unilateral biportal endoscopy (UBE) for degenerative lumbar diseases, this study provides a theoretical foundation for the precise prevention and management of HBL and related complications in clinical practice. Methods A retrospective analysis was conducted on 87 patients who underwent single-segment UBE surgery for lumbar degeneration from June 2022 to June 2023. Detailed records were maintained for demographic characteristics, laboratory indicators and surgical data. HBL was calculated via the Sehat formula (HBL = total blood loss (TBL) - visible blood loss (VBL)). Pearson and Spearman correlation analyses were initially employed to identify factors associated with HBL, followed by multivariate linear regression modelling to identify independent risk factors. Results The mean HBL was 227.40 ± 232.92 mL. HBL was positively correlated with surgical time, postoperative drainage volume, and TBL (P < 0.05) but negatively correlated with postoperative haemoglobin (Hb), haematocrit (Hct), and total protein (P < 0.05). Multivariate linear regression analysis revealed that surgical time (P = 0.049), preoperative platelet count (P = 0.002), postoperative platelet count (P = 0.016), preoperative Hct (P = 0.045), preoperative albumin (ALB) level (P = 0.011), and postoperative total protein level (P = 0.003) were independent risk factors for HBL. Conclusion HBL in UBE surgery for degenerative lumbar diseases is a significant concern that should not be overlooked. Prolonged surgical time, elevated preoperative platelets, low preoperative ALB levels, and low postoperative total protein levels may exacerbate HBL. These risk factors should be closely monitored during the perioperative period to optimize patient management, reduce postoperative complications, and improve overall prognosis.