Objective: Spontaneous spinal epidural hematoma is rare and therefore difficult to diagnose. This study evaluated the clinical features of this condition in patients admitted to our hospital.Patients and Methods: We evaluated 12 patients with spontaneous spinal epidural hematoma who were treated at our hospital. We investigated the following variables in these patients: underlying diseases, medications used, initial symptoms, spinal level affected, whether transported to the hospital by ambulance, department where first evaluated, mass lesion on computed tomography with soft tissue window settings, time interval between symptom onset and diagnosis, treatment received, and Frankel classification on arrival and when last observed.Results: Five patients reported the use of antiplatelet or anticoagulant drugs. All patients in this study reported acute onset of severe pain as the initial symptom, and 10 patients reported some degree of paralysis accompanying the pain. With respect to the morbidity level, the cervical region was the most common site of involvement (n=7). Ten patients were transported to the hospital at night via ambulance. Five patients first visited the Department of Internal Medicine. Seven patients presented with a mass lesion on computed tomography with soft tissue window settings. The time interval between symptom onset and diagnosis ranged from 2 hours to 6 days. Three and 9 patients received conservative and surgical treatments, respectively. No patient showed worsening of Frankel classification.Conclusion: Acute onset of severe pain was the most characteristic clinical symptom. Spontaneous spinal epidural hematoma should be included in the differential diagnosis. Computed tomography with soft tissue window settings may rule out cerebrovascular disease and cardiovascular disease, and specifically detect a hematoma. Subsequent magnetic resonance imaging can diagnose a spontaneous spinal epidural hematoma at an early stage.

Purpose: This study aimed to examine the characteristics of lumbar spondylolysis with acute lumbar spondylolysis on one side and pseudoarthrotic spondylolysis on the other, relative to acute lumbar spondylolysis on one side only.Patients and Methods: Short-tau inversion recovery images obtained through magnetic resonance imaging were used to diagnose 58 patients with acute lumbar spondylolysis with bone marrow edema on one side only. A total of 20 patients who had pars defects on the contralateral side (terminal-stage pseudoarthrotic spondylolysis) were included in the contralateral pseudoarthrosis group (P group). The remaining 38 patients with normal images for the contralateral pars interarticularis were included in the unilateral lesion group, in which the contralateral side was normal (U group). We investigated the union rate, age, sex, lesion laterality, vertebral level, pathological stage, and existing spina bifida occulta in both groups.Results: The P group was characterized by a higher proportion of right-side cases, L5 lesions, more progressed pathological stage, and spina bifida occulta and a significantly lower union rate than the U group.Conclusion: The union rate in patients with lumbar spondylolysis with acute lumbar spondylolysis on one side and pseudoarthrotic spondylolysis on the opposite side was only 15%. We should inform patients with acute unilateral spondylolysis lesions and contralateral pseudoarthrosis about this poor union rate and urge them to choose their therapy accordingly.