Deep brain stimulation in the management of neuropathic pain and multiple sclerosis tremor.

Deep brain stimulation (DBS) of the central gray matter was an important component of the surgical management of chronic, drug-refractory, central neuropathic pain until only a decade ago. However, in the recent past, this technique has been increasingly neglected and has been largely replaced by motor cortex stimulation (MCS). The results of MCS, however, are far from uniform, and the best reports quote a range of 50% to 75% success in providing satisfactory pain relief. In recent years, there has been considerable success in treating various movement disorders, particularly in Parkinson's disease (PD) and dystonia, by chronic high-frequency DBS of nuclear structures in the basal ganglia. This technique has also been shown to be relatively effective in some selected cases of tremulous conditions like essential tremor and posttraumatic tremor. However, when the same techniques have been applied to patients with multiple sclerosis tremor (MST), the results have been mixed. As a result, DBS for MST has often been perceived as an unreliable and inconsistent therapeutic intervention. The authors present their experience with the application of DBS in these two relatively unpopular areas for neuromodulation in the current practice of functional stereotactic neurosurgery. The results demonstrate that with careful patient selection, DBS can offer significant functional benefit in both of these difficult clinical conditions.