Lumbar intraspinal synovial cyst containing gas as a cause for low-back pain

Abstract

To discuss intraspinal synovial cysts caused by degenerative changes involving the posterior articular facets in the lumbar spine and to provide differential considerations for patients with low-back pain. A 70-year-old man with low-back and gluteal pain demonstrating eventual progression of radiating pain into the left thigh, calf, ankle, and foot over a 5-month period. Radiographs of the lumbar spine revealed mild degenerative disk disease at L5-S1 with associated vacuum phenomena of the L5 disk. Degenerative osteophytes were present at L3, L4, and L5. Moderate posterior joint arthrosis was evident at L4-L5 and L5-S1. Computed tomography and magnetic resonance imaging studies revealed an intraspinal gas-containing synovial cyst at the left lateral aspect of the central canal at the level of the left L4-L5 facet articulation. The patient underwent surgical excision of the synovial cyst with remission of symptoms. Gas-containing intraspinal synovial cysts can be a significant finding and a causative factor in patients with low-back pain and pain radiating into the lower extremities. Both computed tomography and magnetic resonance imaging are important in defining intraspinal synovial cysts as a cause of back pain in patients whose low-back pain does not respond to chiropractic care.