Symptomatic Hematoma of Lumbar Facet Joint: Joint Apoplexy of the Spine?

STUDY DESIGN A case report. OBJECTIVES To report and discuss a rare case of epidural hematoma that was considered to be formed as a result of idiopathic bleeding occurring at the facet joint (joint apoplexy). SUMMARY OF THE BACKGROUND DATA Spontaneous spinal epidural hematoma is a relatively rare condition. According to a review article of 199 spontaneous spinal epidural hematomas in the last 2 decades, the majority of these conditions are thought to result from a rupture of the epidural vascular network. Recently, a hemorrhagic lumbar synovial cyst and a hematoma occurring from the ligamentum flavum were reported as rare types of epidural hematoma. METHODS The authors describe the treatment and the clinical, radiologic, surgical, and pathologic findings in one patient with a rare epidural hematoma. RESULTS Magnetic resonance imaging revealed that the extradural mass lesion was continuous with the right L4-5 facet joint; this was confirmed by surgery when the extradural hematoma was directly visualized. The joint cavity was also filled with the hematoma. There was no evidence of preceding cyst formation macroscopically or microscopically. The excised capsule of the left L4-5 facet joint revealed moderate hyperplasia of the synovium with an increased number of capillary vessels. CONCLUSIONS This is the first reported case of radiculopathy considered to be a result of facet joint apoplexy in the absence of any preceding synovial cyst formation. The pathomechanism of the hemorrhage at the lumbar facet joint is unclear, but it is speculated that there could be an association with degenerative change of the facet joint. Surgical excision of this mass was considered to be the definitive treatment.