Abstract
PURPOSE: This study compared hidden blood loss (HBL) among three different endoscopic spinal procedures and investigated its risk factors. PATIENTS AND METHODS: This single-centre retrospective analysis collected data from consecutive hospitalized patients with single-segment lumbar disc herniation (LDH) undergoing unilateral biportal endoscopic discectomy (UBE), percutaneous endoscopic transforaminal discectomy (PETD), or percutaneous endoscopic interlaminar discectomy (PEID) from December 2020 to October 2022. HBL was calculated using Nadler's and Gross's formulas. The authors used Pearson's or Spearman's correlation analysis to explore the relationship between patient characteristics and HBL. Multivariate linear regression analysis was used to identify independent risk factors for HBL. RESULTS: In total, 122 consecutive patients (68 females and 54 males) were enroled in this study. The average HBL was 381.87±218.01 ml in the UBE group, 252.05±118.44 ml in the PETD group and 229.63±143.9 ml in the PEID group (P<0.05). Pearson's or Spearman's correlation analysis showed that operative time, preoperative haemoglobin, preoperative haematocrit, and preoperative Albumin (ALB) were correlated with HBL in the UBE group, while sex, age, operative time, postoperative ALB, and patients' blood volume (PBV) were related to HBL in the PETD group (P<0.05). Operative time and preoperative activated partial thromboplastin time were related to HBL in the PEID group (P<0.05). Multiple linear regression analysis showed a positive correlation between HBL and operative time in all three groups (P<0.001, P<0.001, P<0.05). CONCLUSION: HBL was higher in the UBE group than in the PETD and PEID groups, and operative time may be a common risk factor for the three groups.