[Deep brain stimulation of the ventral intermediate thalamic nucleus in the treatment of essential tremor]

Essential tremor (ET) is the most common movement disorder. In most patients the course of ET is mild and pharmacological therapy controls postural and kinetic components of tremor. The first-line treatment of ET is pharmacotherapy with propranolol, primidone and gabapentin. In patients with marked head and voice tremor, local botulinum toxin injections have been found to be very effective. Despite optimal drug therapies it is estimated that approximately 50% of patients with ET have medication-resistant tremor. ET can cause more functional impairment than parkinsonian resting tremor because most prominent components of ET are postural and kinetic ones. For patients with drug-resistant debilitating tremor, surgical therapy (thalamotomy) and more recently deep brain stimulation (DBS) of the ventral intermediate thalamic nucleus (VIM) is a viable treatment modality. Several long-term studies have confirmed the high effectiveness rate of ablative surgery and thalamic DBS in the treatment of ET. The most striking advantage of thalamic DBS is the possibility of performing bilateral surgery in one operative session with a significantly lower rate of side effects. Nowadays the bilateral staged thalamotomy is performed rarely because of unacceptable side effects. Moreover, many authors have observed that in bilaterally stimulated patients the head and voice tremor have diminished in postoperative course. Thalamic DBS is a very efficacious and safe procedure in the treatment of ET.