An 82-year-old woman complained of severe back pain after a slight fall seven weeks earlier. She was transferred from a traditional oriental hospital to the emergency room of our hospital. Here, the patient was managed conservatively for multi-lev-J Korean Neurosurg Soc 49 : 231-233, 2011 10.3340/jkns.2011.49.4.231 Copyright © 2011 The Korean Neurosurgical Society Chronic spinal epidural hematoma related to Kummell's disease is extremely rare. An 82-year-old woman who had been managed conservatively for seven weeks with the diagnosis of a multi-level osteoporotic compression fracture was transferred to our institute. Lumbar spine magnetic resonance images revealed vertebral body collapse with the formation of a cavitary lesion at L1, and a chronic spinal epidural hematoma extending from L1 to L3. Because of intractable back pain, a percutaneous vertebroplasty was performed. The pain improved dramatically and follow-up magnetic resonance imaging obtained three days after the procedure showed a nearly complete resolution of the hematoma. Here, we present the rare case of a chronic spinal epidural hematoma associated with Kummell's disease and discuss the possible mechanism.

54ted to our institute with severe back pain and right thigh pain. Five years previously, he developed severe back pain after a light fall and the magnetic resonance imaging (MRI) revealed a fresh compression fracture at L1. The patient was diagnosed with AS at that time and underwent percutaneous vertebroplasty (Fig. 1). The lowest T-score on DEXA bone mineral density was -3.57 at that time. The patient presented with only mild back discomfort after the vertebroplasty. However, the back and thigh pain progressively worsened without any history of trauma for one month before re-admission. Ambulation was very limited and the patient was then admitted to the hospital again. On physical examination, there was no motor weakness but there was decreased sensation to pinprick in the right L2 dermatome. The results of the straight leg raising test and femoral stretch test were negative. Simple radiographs showed severe degenerative changes, spondylosis, aggravated kyphosis and a stress fracture through the ossified posterior segment, below the prior vertebroplasty ( Fig. 2A). Computed tomography scanning confirmed the stress fracture (Fig. 2B). The MRI revealed a right foraminal cystic mass at the L2-L3 level with effacement of the nerve root (Fig. 3). The cyst's interior signal was isointense with the cerebrospinal fluid on T1-weighted images and hyperintense on T2-weighted sequences. Administration of gadolinium resulted in little enhancement of the cyst's wall. A right L2-L3 total facetectomy and posterolateral fusion were performed to remove the lesion (Fig. 4). During surgery, a 1.6 cm cystic le- INTRODUCTIONSynovial cysts usually develop from the synovial capsule of the facet joints. Although their etiology is unclear, facet joint arthropathy and underlying spinal instability are known to be associated with the formation of synovial cysts and worsening symptoms 1,7) . Most intraspinal synovial cysts are located in the lower lumbar spine, where the greatest degree of movement is present 4) . In rare cases, they have also been described with inflammatory changes of the facet joints in association with rheumatoid arthritis and undifferentiated spondyloarthropathy 2,3,6) . However, there has been no report of intraspinal synovial cysts associated with ankylosing spondylitis (AS). We report a patient who developed a radiculopathy caused by foraminal synovial cyst associated with AS accompanying posterior element fracture. CASE REPORTA 55-year-old man with a five year history of AS was admit-J Korean Neurosurg Soc 50 : 54-56, 2011 10.3340/jkns.2011.50.1.54 Copyright © 2011 The Korean Neurosurgical Society Ankylosing spondylitis (AS) is frequently associated with inflammatory lesions of the spine and continuous fatigue stress fractures; however, an association with an intraspinal synovial cyst has not been previously reported. A 55-year-old man with a five year history of AS who presented with back pain and a right radiculopathy was admitted to the hospital. Five years previously, he underwent a percutaneous vertebrop...