Synovial cysts of the lumbar facet joints: a retrospective magnetic resonance imaging study investigating their relation with degenerative spondylolisthesis.

Patients with synovial cysts of the facet joints were compared with patients with degenerative spondylolisthesis (DS), based on the magnetic resonance imaging (MRI) findings of their spondyloses. The lumbar MRI of 30 patients with DS (group 1) 24 patients with synovial cysts of the facet joints (group 2) were studied. All patients were evaluated in terms of facet joint arthritis, disc degeneration, facet joint effusion, and the thickness of the flaval ligament. 54.1% of the patients with synovial cysts had associated DS. The mean grade of disc degeneration (2.43+/-0.50 and 2.13+/-0.68 in groups 1 and 2, respectively) and the mean thickness of the flaval ligament (3.20+/-1.22 mm and 3.83+/-1.46 mm in groups 1 and 2, respectively) did not differ between the groups (p=0.093 and p=0.097). The mean grade of facet joint osteoarthritis (2.53+/-0.51 and 2.08+/-0.72 in groups 1 and 2, respectively) was significantly higher in group 1 (p=0.18). The co-existance of synovial effusion was significantly higher in cases with synovial cysts. (p=0.008). Synovial cysts are associated with DS and facet joint osteoarthritis. The presence of synovial effusion and the high degree of disc degeneration are prominent features in patients with synovial cysts. Although osteoarthritis and DS are highly concomitant with facet joint synovial cysts, both conditions do not invariably lead to a cyst formation.