[Treatment of a case of generalised dystonia using subthalamic stimulation].

INTRODUCTION Generalised dystonia is an entity that does not usually respond well to medical treatment. Different surgical targets have therefore been used in the treatment of dystonia, including several thalamic nuclei or the internal globus pallidus. The subthalamic nucleus plays a fundamental role in the physiology of the basal ganglia. It could therefore be considered to be a good potential target for stimulation. CASE REPORT A patient who was confined to a wheelchair and who had not responded to a number of different medical treatment protocols or to a bilateral thalamotomy was treated with bilateral deep brain stimulation in the subthalamic nucleus. Tetrapolar electrodes were placed in both subthalamic nuclei in two stages. The patient showed a significant improvement from the very beginning of the post-operative period. After six months' progression, the patient was able to walk unaided and the dystonic seizures diminished significantly. Unfortunately, the patient died from choking. We used a bipolar stimulation protocol at 50 Hz with 210 micros pulses, which do not reach the levels of maximum charge density that are considered to be harmful. CONCLUSION The subthalamic nucleus can be a good surgical target for deep brain stimulation in cases of generalised dystonia; it responds well to stimulation at intermediate frequencies with safe charge densities.