Hidden blood loss and risk factors in percutaneous endoscopic cervical discectomy.

Objectives: The study aimed to evaluate the hidden blood loss (HBL) and its possible risk factors in patients undergoing percutaneous endoscopic cervical discectomy (PECD) via posterior approach to better guide the management of perioperative anemia in patients.

Patients and methods: The study retrospectively analyzed the clinical data of 60 patients (33 males, 27 females; mean age: 55.3±7.9 years; range, 40 to 69 years) treated with PECD between March 2019 and January 2023. All patients had cervical disc herniation or radiculopathy. General information (age, sex, height, weight, body mass index, Visual Analog Scale pain score, and comorbidities), surgery-related data (surgical time, number of surgical segments, American Society of Anesthesiologists score, and blood transfusions), and laboratory-related results (hemoglobin, hematocrit, albumin, and blood glucose) of the patients were collected from the hospital database. The patients' HBL was calculated based on the patients' height, weight, and hematocrit levels, and then the risk factors were analyzed by multiple linear regression.

Results: Only five patients underwent two-segment PECD via a single channel. The mean surgical time and HBL were 110.3±34.0 min and 114.5±50.2 mL, respectively. Six patients who were not anemic preoperatively developed anemia postoperatively, and the difference in the incidence of anemia between preoperative and postoperative periods was statistically significant (p=0.013). Multiple linear regression analysis showed that HBL was associated with surgical time and the number of surgical segments (p<0.001).

Conclusion: Hidden blood loss after PECD may represent a significant issue, with a risk of causing anemia. The number of surgical segments and surgical time are independent risk factors for HBL. Spine surgeons should emphasize the adverse effects of HBL to ensure the safety of patients in the perioperative period.