Cervical myelopathy treated by canal-expansive laminaplasty. Computed tomographic and myelographic findings.

The operation known as canal-expansive laminaplasty has the following advantages over wide laminectomy: (1) osseous protection of the spinal cord is retained, (2) the invasion of the cord by scar tissue is minimized, and (3) the stability of the spine is retained. We are reporting the clinical, computed tomographic, and computed myelographic findings before and after this operation in twenty-four patients with cervical myelopathy due to cervical spondylosis, spinal stenosis, or ossification of the posterior longitudinal ligament. The clinical results were excellent in four patients, good in eighteen, and fair in two. Symmetrical expansion of the spinal canal was clearly demonstrated by computed tomograms, and the metrizamide ring on the myelograms had a normal rounded curvature.

Microangiographic study of spinal cord injury and myelopathy.

Post-mortem microangiography has been performed in 12 patients with traumatic cervical cord injury, 2 patients with myelopathy, and one patient with post-traumatic syringomyelia. Microangiography defined 4 zones in the injured spinal cord. In traumatic injury, the size and extent of the non-filling area (Zone 1) was directly related to the injury force. Subsequently these areas became cavitated. Surrounding the non-filling area, widely extending areas demonstrated filling of capillaries but showed damaged neurons and axons (Zone 2). In the chronic stage, Zone 2 replaced by gliomesenchymal tissue. The capillaries in the gliomesenchymal scars revealed a distorted abnormal arrangement (Zone 3). In a case with myelopathy, the hypervascular areas (Zone 4) were observed just around the chronically compressed area. The vascular increases were considered to be a reaction against chronic compression. In a patient with post-traumatic syringomyelia, the vascular network of the posterior grey matter disappeared and the central arteries were distorted by the distending forces of the syrinx. The microangiographs suggested that vascular factors might play a significant role in original cavity formation; but in cavity extension, these factors were not primary.