Rehabilitative neurosurgery: posttraumatic syndromes.

Distinct chronic posttraumatic syndromes, ascribed to neurological deficits of patients suffering severe head injuries and being in prolonged coma, are much less frequently encountered in the literature than acute traumatic syndromes. The major components of the posttraumatic midbrain syndrome, resulting from compressive necrosis or vascular infarction at the midbrain level, are ipsilateral cerebellar signs (the predominant one being intention tremor), contralateral pyramidal signs (the predominant one being a spastic-dystonic hemiparesis), dysarthria, and mild to moderate intellectual impairment. Significant bilateral cerebellar dysfunction following head injury, without pyramidal, extrapyramidal, or pseudobulbar signs, constitutes a posttraumatic cerebellar syndrome. Its most disabling component, namely posttraumatic intention tremor, may be alleviated by thalamotomy. Following severe closed head injury, an infrequently encountered posttraumatic entity of dystonic hemiplegia or hemiparesis, which may be alleviated by thalamotomy, can occur, but does not have a specific neuroanatomical basis. Intention tremors following severe head injuries, rarely associated with hydrocephalus and without other significant cerebellar findings, can develop as a dysfunction of the cerebellofugal outflow system. While chronic posttraumatic syndromes can be complex and difficult to treat, cerebellar stimulation has been utilized ipsilaterally to modulate limb spasticity, and bilateral ventrolateral cryothalamectomies staged 4-6 months apart have been successful in alleviating severe (intractable) intention tremors.