The chance of a postoperative complication of epidural hematoma after spine surgery is not significant; according to incomplete statistics, the probability of a symptomatic postoperative epidural hematoma in all spine surgeries is approximately 0.10% to 0.24%. However, if it occurs and is not detected and treated promptly, it can lead to serious complications.Gregory et al. conducted a literature review on the epidemiology, etiology, diagnosis, and treatment of postoperative epidural hematomas, which was published in J Spinal Disord Tech. Overview: Asymptomatic epidural hematomas are very common in lumbar spine surgery and can be found by MRI: 89% of patients without drainage after lumbar spine surgery develop an asymptomatic epidural hematoma. Conversely, symptomatic epidural hematomas are rare, occurring in 0.10% to 0.24% of patients, and thus have been studied only to a limited extent. In one study, elevated preoperative diastolic blood pressure, covering the dura with gelatin sponge, and high postoperative drainage were found to be three risk factors for postoperative symptomatic epidural hematoma, and other studies besides this one have identified several other risk factors, such as NSAID use, RH-positive blood, and age over 60 years. Closed drainage is performed after all orthopedic procedures, and our routine use of drainage in lumbar spine surgery, while not reducing the incidence of symptomatic hematomas, will reduce the incidence of postoperative asymptomatic epidural hematomas. In a prospective study, MRI on day 1 after lumbar spine surgery in 50 patients showed a statistically significant decrease in the incidence of asymptomatic epidural hematoma after drainage from 89% to 36%. In addition, only 1 patient developed a moderate sized hematoma after drainage, while 8 patients without drainage developed a hematoma. In the study of postoperative anticoagulation and the use of antiplatelet agents, postoperative anticoagulation did not increase the risk of postoperative epidural hematoma as long as the international normalized rate (INR) was <2.0, whereas it increased the risk of postoperative epidural hematoma if the INR was >2.0. Antiplatelet agents did not increase the incidence of postoperative epidural hemorrhage after spinal surgery. Diagnosis: Typically, epidural hematomas occur within 24 hours postoperatively, but some authors have reported that the onset of lumbar hematoma can be delayed until after drainage tube removal or even 3 days after surgery. Almost all patients with epidural hematoma have evidence of neurological damage, and Kao reported that approximately 80% of patients with lumbar epidural hematoma have progressive loss of muscle strength, 76% have saddle numbness, and 56% have sudden onset of severe pain. When either symptom is present, the patient needs an MRI to evaluate for an epidural hematoma. Treatment: Once symptoms are present and confirmed by MRI, the patient requires urgent reoperation for hematoma removal, and Kao et al. showed a significant correlation between time to hematoma removal and postoperative neurological recovery. The mean time to hematoma clearance was 7.4 hours in patients with full neurological recovery, compared with 17.9 hours in patients with residual neurological deficits. It has been shown that the severity of symptoms and the time to hematoma clearance are the two main factors affecting neurological recovery from epidural hematoma, and that patients who undergo surgical removal of the hematoma within 12 hours of symptom onset are most likely to recover completely. In conclusion, the development of a symptomatic epidural hematoma is a rare postoperative complication of spine surgery, but if not detected and treated promptly, it can lead to a long-term neurological damage that can have serious consequences. If postoperative numbness, weakness, or severe pain occurs, MRI should be performed to further clarify the diagnosis, and once found, the epidural hematoma should be surgically removed to facilitate neurological recovery.