Unilateral globus pallidus internus stimulation improves delayed onset post-traumatic cervical dystonia with an ipsilateral focal basal ganglia lesion. (Short Report).

Treatment with unilateral left globus pallidus internus (GPi) deep brain stimulation is reported in a patient with severe delayed onset post-traumatic cervical dystonia. He had sustained severe head trauma at the age of 17 and had developed a mild right hemiparesis. Three years after the head injury, cervical dystonia with head turning to the left side developed. Magnetic resonance imaging (MRI) showed a discrete GPi lesion on the left side. At the age of 23, he underwent unilateral left GPi deep brain stimulation. He experienced immediate but short lasting benefit from the microlesioning effect of the electrode. With activation of deep brain stimulation, there was significant improvement of the cervical dystonia, persisting for 12 months of follow up. This case underlines the importance of the globus pallidus internus in the generation and amelioration of cervical dystonia.

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The pathophysiology of cervical dystonia is not well understood, and the mechanism of improvement associated with stereotactic surgical procedures is not clear either. (1-3) The rationale for globus pallidus internus (GPi) stimulation in dystonia is partly based on the observation of an improvement in L-DOPA induced involuntary movements by pallidotomy or pallidal stimulation in patients with Parkinson's disease. Although a role of the GPi in the pathogenesis of dystonia is strongly suspected, presumably acting through alteration of thalamic inhibition, (4) focal traumatic lesions of the GPi have only rarely been reported to produce secondary dystonia.

In this paper, we describe a patient who sustained a motor vehicle accident that eventually led to a focally restricted lesion of the GPi with cervical dystonia, which was successfully treated by unilateral GPi stimulation.

CASE REPORT

A 23 year old man sustained a severe closed head injury in a car accident at the age of 17. He had a right hemiparesis and was obtunded for several weeks before recovering slowly over the next few months. Three years after the initial head injury, cervical dystonia developed, and this progressed in severity for six months. The cervical dystonia did not improve with medical treatment, which included clonazepam, L-DOPA, baclofen, and trihexyphenidyl. Two years later, he was treated with botulinum toxin injections to …