Histopathology of the spinal cord reveals wallerian degeneration, malacia and fibrosis at the site of compression. This is enhanced by measuring the sagittal ratio by comparing the width of the vertebral canal and comparing it to the width of the vertebral body. Confirmation of the compression can be accomplished by performing a myelogram. Clinical signs include symmetric ataxia, weakness and spasticity in all 4 limbs, usually worse in the rear limbs. Hyporeflexia over the neck and trunk may be present, particularly in severe or longstanding cases.
Gross pathology is unremarkable.
Histologic lesions are in the brainstem and spinal cord. Major lesions are diffuse neuronal dystrophy. Demyelination is usually significant. Low serum vitamin E levels may support a diagnosis. However, antemortem diagnosis is a diagnosis by exclusion.