Cervical ligamentum flavum ossification. Two case reports.

A 58-year-old woman (Case 1) presented with disturbance of fine movement and gait. Magnetic resonance (MR) imaging and computed tomography (CT) demonstrated bilateral ossified ligamentum flava at the C3-4 and C4-5 levels and severe cervical canal stenosis. She underwent posterior decompression and despite strong adhesion to the dura mater, the ossified ligamentum flavum was removed without inducing liquorrhea. Her neurological symptoms improved postoperatively. A 63-year-old man (Case 2) was admitted with disturbance of fine movement and gait that had developed gradually. MR imaging and postmyelography CT demonstrated cervical canal stenosis via the ossified posterior longitudinal ligament at the C4-6 levels and ossified ligamentum flavum on the right at the C4-5 levels. He underwent right posterior decompression of C4-5. After right hemilaminectomy of C4-5, the ligamentum flavum was exposed. Neither the ligamentum flavum nor the ossification had adhered to the dura mater, so complete removal was successful and he recovered completely from his neurological symptoms. Diffuse-type ossified ligamentum flavum had adhesion to the dura mater, as in our Case 1, whereas focal-type ossified ligamentum flavum did not, as in our Case 2. This information is useful for treatment planning.