Abstract
A 78-year-old woman was admitted to our hospital in October 1997 because of numbness of both her hands, defect of precision motion, and gait disturbance. At that time, the JOA Score (Ruling Standard for the Treatment of Cervical Myelopathy of Japan Orthopedics Association) was 7 out of 17. On epidural mass was found posterior to the odontoid, which showed low signal intensity in T1 and T2 weighted sagittal views. In a sagittal view with Gd-DTPA, we did not find contrast enhancement in the mass, and we discouered that the mass was severely compressing the spinal cord. We diagnosed that the myelopathy was caused by the epidural mass. Laminectomy of C1 and C2 and occipito cervical fusion were performed without removing the mass. After surgery, mR imaging showed a reduction in the sige of the mass, and the JOA score was improved from 7 to 11 out of 17. In the case of instability and arthrotic change of the atlanto-axial joint, fibrocartilage dysplasia could be caused by chronic and mechanical stimulation which repeatedly produced the fissure and restoration of the ligament transversum atlantis. The mass was histologically reactive hypertrophy of the ligament transversum atlantis ; therefore we could expect that the mass would be reduced in size by only fixing the atlanto-axial joint.
