Perioperative Hidden Blood Loss in Lumbar Disk Herniation Patients With Percutaneous Endoscopic Transforaminal Discectomy and Influencing Factors.

This was a retrospective study.This study aimed to evaluate hidden blood loss (HBL) and its influencing factors in lumbar disk herniation (LDH) patients treated with percutaneous endoscopic transforaminal discectomy (PETD).PETD is a minimally invasive spine surgery and is widely used to treat LDH. It is generally believed that there is less bleeding during PETD. However, HBL during the perioperative period is always ignored.From January 2018 to March 2021, 74 LDH patients treated with PETD was selected. The patient's sex, age, height, weight, previous medical history (hypertension and diabetes) and other basic information were recorded. The preoperative fibrinogen (FIB) level, activated partial thromboplastin time and prothrombin time were recoded. The hemoglobin, hematocrit, and platelet immediately after admission and the next day postoperative were recorded. The surgical time, intraoperative blood loss, intervertebral disk degeneration grade and soft tissue thickness of the PETD approach were recorded. The total blood loss was calculated according to the Gross formula, and then HBL was calculated based on total blood loss and visible blood loss (VBL). The influencing factors were analyzed by single factor correlation analysis and multivariate linear regression analysis.Among the 74 patients, there were 34 males (20-68 y old) and 40 females (26-75 y old). The mean amount of VBL was (85.04±26.53) mL and HBL was (341.04±191.15) mL. There were statistically significant differences between HBL and VBL (P=0.000). Multiple linear regression analysis showed that sex (P=0.000), disk degeneration grade (P=0.000), preoperative FIB level (P=0.022) and preoperative platelet (P=0.026) were independent risk factors that contributed to HBL, but age (P=0.870), BMI (P=0.480), hypertension (P=0.867), diabetes (P=0.284), soft tissue thickness (P=0.701), preoperative prothrombin time (P=0.248) and preoperative activated partial thromboplastin time (P=0.521) were not.There was a large amount of HBL during the perioperative period of PETD in patients with LDH. Sex, disk degeneration grade, preoperative FIB level and preoperative platelet are the independent risk factors of HBL in the perioperative period of PETD. More attention should be paid to the patients with risk factors to ensure perioperative safety.