Unilateral deep brain stimulation of the right globus pallidus internus in patients with Tourette's syndrome: two cases with outcomes after 1 year and a brief review of the literature.

Tourette's syndrome is a complex neuropsychiatric disorder, characterized by tics. Bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) has been considered to be an effective treatment for refractory Tourette's syndrome. Postoperative outcomes are described after 12 months' follow-up in a 41-year-old male patient and a 22-year-old male patient with Tourette's syndrome, both of whom underwent unilateral electrode implantations into the right GPi for DBS. These patients were diagnosed with Tourette's syndrome in childhood and, despite long-term therapy with a range of antipsychotic medications, continued to experience disabling tics in adulthood. Improvements in tic severity of 58.5% and 53.1% were observed at 12 months in the older and younger patient, respectively; improvements were determined by the Yale Global Tic Severity Scale. Both patients also experienced reductions in tic frequency and reported improvements in their health-related quality of life. Improvements in tics were similar to previous reports involving patients who underwent bilateral GPi DBS. These cases suggest that unilateral DBS of the right GPi is effective and might be a viable surgical choice for some patients with Tourette's syndrome.