[Deep brain stimulation of the posterior subthalamic area (Zi/Raprl) for intractable tremor]

Tremor in the proximal arm muscle, trunk, or legs is often resistant to the standard stereotactic surgery of the thalamic ventrointermediate nucleus. We have performed deep brain stimulation (DBS) of the posterior subthalamic area for those intractable tremors. The white matter area between the red nucleus and the subthalamic nucleus was targeted on the T2-weighted MR-CT fused image. Inhibitory effect on the tremor was tested with macrostimulation. The somatosensory-evoked potential recorded through DBS contacts demonstrated characteristic biphasic pattern. Eight cases with severe essential tremor and 18 of tremor-dominant Parkinson disease were treated with unilateral DBS of the area including the zona incerta and the prelemniscal radiation (Zi/Raprl). Tremors including the proximal part have been well controlled for 24 months after the operation. The stimulation parameters have been almost stable during the follow-up period. There was no obvious adverse effect of stimulation. We conclude that Zi/Raprl-DBS is a safe and effective treatment on Parkinsonian and essential tremor.