AIM: To compare the regional tissue oxygen saturation under general, spinal, and epidural anesthesias during the posterior lumbar discectomy procedures performed in the prone position. MATERIAL and METHODS: A total of 90 patients with an American Society of Anesthesiologists score I-III were evaluated. Using the research randomizer program, the patients were split into three groups: group of general anesthesia (GA, Group I), group of spinal anesthesia (SA, Group II), and group of epidural anesthesia (EA, Group III). Each patient received non-invasive peripheral arterial oxygen saturation (SpO2), three-lead electrocardiography, non-invasive mean arterial blood pressure (MAP), and the in Spectra TM StO2 Spot Check device with near-infrared spectroscopy (NIRS) technology. The group GA also received end-tidal CO2 monitoring and tissue hemoglobin index (THI), and StO2 monitoring. RESULTS: The data of 90 patients showed that age, weight, height, American Society of Anesthesiologists score, amount of bleeding, duration of surgery, and anesthesia were not statistically significant. Tissue oxygen saturations were detected between groups at the 15th, 30th, 45th, and 60th minutes. The values of group EA at the 15th, 30th, and 45th minutes were higher than group SA (p=0.001; p<0.05). CONCLUSION: This study shows that general anesthesia, as opposed to spinal and epidural anesthesia, offers superior thenar tissue oxygenation in a prone position during posterior lumbar discectomy surgery, despite the ongoing debate over the pros and cons of this position.