Sensory abnormalities and dysaesthesias in the anterior spinal artery syndrome

We present three patients with a nontraumatic cervical anterior spinal artery syndrome, two of whom developed painful burning dysaesthesias below the level of spinal cord lesion, refractory to opiate, anticonvulsant and tricyclic antidepressant therapy. Quantitative sensory testing and neurophysiological assessment showed absence of pain and temperature sensation below the level of the lesion, with preservation of light touch, vibratory and position sensibilities and cortical somatosensory evoked potentials in all three patients. Dysaesthesias in both affected patients were exacerbated by somatosensory input attributed to intact posterior column function. Posterior column electrical stimulation worsened the dysaesthesias in one affected patient, and was ineffective in the other. Both patients affected with dysaesthesias showed significant improvement in motor function and developed clinical spasticity, while the third patient developed neither dysaesthesias nor spasticity, but remained flaccid without motor improvement, suggesting a more complete lesion of anterolateral spinal pathways. These cases illustrate that lesions of the anterolateral spinal cord may lead to the development of dysaesthesias, perhaps related in part to selective neospinothalamic deafferentation and preservation of the posterior columns.