Rare ligamentum flavum cyst causing incapacitating lumbar spinal stenosis: Experience with 3 Chinese patients.

Three Chinese patients suffered from severe lumbar spinal stenosis with debilitating symptoms due to a rare condition of ligamentum flavum cysts in the midline of the lumbar spine. This disease is distinct from synovial cyst of the facet joints or ganglion cysts, both intraoperatively and histopathologically. Magnetic Resonance imaging features of the ligamentum flavum cyst are also demonstrated. We share our surgical experiences of identification of the ligamentum flavum cysts, decompression and excision for two of the patients with demonstrably good recovery. This disease should be considered in the differential diagnosis of an extradural instraspinal mass in patients with lumbar spinal stenosis.