Spontaneous Spinal Epidural Hematoma Associated with the Ossification of Ligamentum Flavum of the Thoracic Spine

ABSTRACT

Spontaneous Spinal Epidural Hematoma has been reported to be associated with vascular malformations, tumors, infections, pregnancy, ankylosing spondylitis, rheumatoid arthritis, artherosclerosis, and hypertension. Approximately half of the cases, however, have no apparent cause. The most widely accepted hypothesis of the source of bleeding is that epidural veins are torn by the variations of abdominal or thoracic pressure. The normal hemodynamic fluctuations during usual daily activities are not, however, enough to explain the rare incidence of the spontaneous spinal epidural hematoma, requiring further consideration of the pathogenic factors. The author experienced a case of spontaneous spinal epidural hematoma associated with the ossification of the ligamentum flavum at the lower portion of the hematoma. Venous bleeding from distended epidural veins was observed at the lateral sides of the dural sac after removal of the hematoma. In addition, no vascular malformation was not found in the operative field. Consequently, the auther cautiously suggests that the ossification of the ligamentum flavum may have resulted in the formation of an abnormally dilated vein which ultimately caused bleeding in the patient.