Abstract:

Hidden blood loss (HBL) refers to blood seeping into tissue spaces or blood loss that cannot be directly observed due to causes such as haemolysis. It is common during percutaneous endoscopic lumbar discectomy (PELD) and unilateral bi-lateral endoscopic discectomy (UBE) procedures and can have a significant negative impact on postoperative recovery of patients. The occurrence of HBL is primarily associated with blood seeping into tissue spaces and haemolysis mediated by oxygen-free radicals. The anatomical characteristics of the Batson paravertebral venous plexus in the spinal region, the rich blood supply of the vertebral cancellous bone, the spaces within loose connective tissue and continuous intraoperative perfusion fluid constitute the specific basis for its occurrence. Key influencing factors include advanced age, increased thickness of the paraspinal muscles, high body mass index (BMI), diabetes, hypertension, osteoporosis, as well as fusion procedures, multi-segment operations and prolonged operative time. Whereas the use of tranexamic acid is a key protective factor. The prevention and control of HBL should run through the entire perioperative period, including the preoperative identification and management of modifiable risk factors.The intraoperative measures such as controlled hypotension, maintenance of normal body temperature and the appropriate use of tranexamic acid should be adopted. After the operation, haematological parameters need to be dynamically monitored. Blood transfusion or iron supplementation treatment should be given if necessary.

Key words: spinal diseases, blood loss, percutaneous discectomy, unilateral bi-portal endoscopic discectomy