Abstract
BACKGROUND: Hidden blood loss (HBL) is a notable complication in spinal endoscopic procedures. This study aims to compare tissue damage and hidden blood loss between two minimally invasive spinal techniques: unilateral biportal endoscopic lumbar discectomy (UBE) and percutaneous endoscopic interlaminar discectomy (PEID). Furthermore, the study examines the risk factors contributing to hidden blood loss in each procedure. PATIENTS AND METHODS: A single-center retrospective cohort study was conducted on 86 patients who underwent unilateral biportal endoscopic lumbar discectomy (UBE) and 73 patients who received percutaneous endoscopic interlaminar discectomy (PEID) between January 2021 and December 2023.Demographic data, blood loss parameters, and serum levels of creatine kinase (CK) and C-reactive protein (CRP) were recorded. Pearson or Spearman correlation analyses were conducted to evaluate associations between patient characteristics and HBL. Additionally, multiple linear regression analysis was used to identify independent risk factors for HBL. RESULTS: A total of 159 consecutive patients were included in this study, consisting of 83 females and 76 males. The average hidden blood loss (HBL) was 431.00 ± 160.52 ml in the UBE group and 328.40 ± 87.71 ml in the PEID group, showing a statistically significant difference (P < 0.05). Pearson or Spearman correlation analysis indicated that in the UBE group, HBL was associated with operation time, preoperative hematocrit (Hct), ASA classification, and paraspinal muscle thickness. In the PEID group, HBL was correlated with operation time, preoperative activated partial thromboplastin time (APTT), paraspinal muscle thickness, and the presence of diabetes (P < 0.05). Multiple linear regression analysis demonstrated a positive correlation between HBL and operation time in both groups (P < 0.05), identifying operation time as an independent risk factor for HBL. Furthermore, CRP and CK levels were generally lower in the PEID group compared to the UBE group, particularly on postoperative day 3 for CRP and postoperative day 1 for CK. Both total blood loss and hidden blood loss were significantly lower in the PEID group than in the UBE group. CONCLUSION: Compared to UBE, PEID shows superior results regarding surgical trauma, total blood loss, hidden blood loss (HBL), and postoperative hematocrit (Hct) reduction. Consequently, PEID is recommended as the treatment of choice for younger patients or those with compromised baseline perioperative conditions.Additionally, Hidden blood loss remains a critical factor, and surgical duration presents a shared risk in both procedures.