title: Lumbar intraspinal synovial cyst containing gas as a cause for low-back pain.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  The patient underwent surgical excision of the synovial cyst with remission of symptoms.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Radiology, Palmer College of Chiropractic, Davenport, IA 52803, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Firth
mesh_terms: D000368:Aged; D005740:Gases; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000473:pathology; D017116:Low Back Pain / Q000175:diagnosis / Q000209:etiology*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D010147:Pain Measurement; D013581:Synovial Cyst / Q000150:complications* / Q000175:diagnosis* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D005740:Gases