Neuroradiological examination of thoracic radiculomyelopathy due to ossification of the ligamentum flavum.

Sixteen cases of thoracic radiculomyelopathy due to ossification of the ligamentum flavum (OLF) were analyzed. The patients ranged in age from 39 to 78 years (average 57 years). There were 13 men and 3 women. A significant predilection of OLF for the lower thoracic spine (T9/10, T10/11, T11/12) was noticed. Plain X-ray of the thoracic spine and multidirectional tomography could give important information about the site of ossification. Computed tomography with the intrathecal injection of the water-soluble contrast material clearly demonstrated the ossification and the degree of compression of the spinal cord. The disadvantages of using computed tomography for diagnosing OLF included the necessity for the scan level to be previously decided by other methods because computed tomography of the entire spine was impractical. Magnetic resonance imaging was performed in 14 patients and gave important information about OLF and the compression of the spinal cord. The combination of MRI and computed tomography seems the most useful for the precise diagnosis of OLF.