Deep brain stimulation of the centre median-parafascicular complex in patients with movement disorders

The centre median-parafascicular (CM-Pf) complex of the thalamus is considered to be a possible target for deep brain stimulation (DBS) in patients with movement disorders. In a prospective study on the effect of CM-Pf DBS versus somatosensory thalamic DBS on chronic neuropathic pain, three of 12 patients had additional movement disorders. Bifocal quadripolar electrodes were implanted by computed tomography guided stereotactic surgery under local anaesthesia contralaterally to the side of the pain for test stimulation. Two of the three patients with movement disorders had permanent implantation of CM-Pf electrodes. During test stimulation of the left CM-Pf complex for several days, a 67 year old woman received no benefit with respect to the neuropathic pain, but the choreoathetotic movements of her right foot ceased. As the pain syndrome was not improved, she decided not to have permanent implantation. A 74 year old man with postzoster neuralgia and allodynia enjoyed excellent relief from his pain with chronic CM-Pf DBS. In addition, improvement in the tremor at rest was noted. A 72 year old man had sustained reduction in his stump dyskinesias. Further evaluation of the possible role of the "forgotten" central and medial thalamic nuclei in the treatment of movement disorders may be warranted.