Lumbar synovial cysts: experience with nine cases.

Nine patients treated surgically for lumbar spinal synovial cyst were reviewed. Four patients had synovial, two had ganglion, one had posterior longitudinal ligament, and two had ligamentum flavum cyst. Synovial cysts had a single layer of epithelial cells in the inner layer of the cyst with continuity with the facet joint. Ganglion cyst had no continuity with the facet joint and epithelial lining was present in one and absent in one case. Posterior longitudinal ligament and ligamentum flavum cysts had no continuity with the facet joint and no epithelial lining. Magnetic resonance imaging showed the cysts better than computed tomography. All patients treated for nerve root compression or lumbar spinal canal narrowing. One patient suffered recurrence 1 year later and was reoperated. Operative results were excellent in six and good in three patients. Lumbar spinal synovial cysts should be considered in differential diagnosis of lumbar radiculopathy/neurogenic claudication and is surgically treatable.