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Background: This study set out to determine whether structural changes are present outside the thalamus after thalamotomy in patients with essential tremor (ET), specifically in the cerebellorubrothalamic tracts. We hypothesized that diffusion tensor imaging (DTI) would detect these changes., Methods: We collected DTI scans and analyzed differences in Fractional Anisotropy (FA) and Mean Diffusivity (MD) between the left and right superior and middle cerebellar peduncle in ET patients that have undergone unilateral, left, thalamotomy and ET patients that did not undergo thalamotomy (control group). We used classical ROI-based statistics to determine whether changes are present., Results: We found decreased FA and increased MD values in the right superior cerebellar peduncle leading to the left, lesioned thalamus, only in the thalamotomy group., Conclusions: Our study suggests long-term structural changes in the cerebellorubrothalamic tract after thalamotomy. This contributes to further understanding of the biological mechanism following surgical lesions in the basal ganglia., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The role of the motor thalamus as surgical target in stereotactic neurosurgery for different kinds of tremor is discussed. For tremor in Parkinson's disease, the subthalamic nucleus becomes more and more often the surgical target, because this target also gives relief of other and more incapacitating symptoms (hypokinesia, rigidity). Stimulation is as effective in tremor suppression as coagulation but has less adverse events and permits bilateral surgery. In selected cases, thalamotomy can still be indicated., (Copyright 2002 Movement Disorder Society)

Three target structures are available in stereotactic surgery for Parkinson's disease: the thalamus, the globus pallidus and the subthalamic nucleus. The subthalamic nucleus appears to be the most promising structure. However, the thalamus can be considered in the case of an incapacitating tremor presenting as a primary symptom. Surgery in the globus pallidus may be as effective as in the subthalamic nucleus, but in the latter it is often accompanied by a reduction in dopaminergic medication. The surgical technique of electrical stimulation causes fewer adverse effects than that of coagulation and can therefore be applied bilaterally, but does require more intense postoperative care. In the selection of patients for surgery, levodopa responsiveness plays an important role in predicting effectiveness, except in the case of tremor.

Background: Deep-brain stimulation through an electrode implanted in the thalamus was developed as an alternative to thalamotomy for the treatment of drug-resistant tremor. Stimulation is thought to be as effective as thalamotomy but to have fewer complications. We examined the effects of these two procedures on the functional abilities of patients with drug-resistant tremor due to Parkinson's disease, essential tremor, or multiple sclerosis., Methods: Sixty-eight patients (45 with Parkinson's disease, 13 with essential tremor, and 10 with multiple sclerosis) were randomly assigned to undergo thalamotomy or thalamic stimulation. The primary outcome measure was the change in functional abilities six months after surgery, as measured by the Frenchay Activities Index. Scores for this index can range from 0 to 60, with higher scores indicating better function. Secondary outcome measures were the severity of tremor, the number of adverse effects, and patients' assessment of the outcome., Results: Functional status improved more in the thalamic-stimulation group than in the thalamotomy group, as indicated by increases in the score for the Frenchay Activities Index (from 31.4 to 36.3 and from 32.0 to 32.5, respectively; difference between groups, 4.4 points; 95 percent confidence interval, 2.0 to 6.9). After adjustment for base-line characteristics, multivariate analysis also showed that the thalamic-stimulation group had greater improvement (difference between groups, 5.1 points; 95 percent confidence interval, 2.3 to 7.9). Tremor was suppressed completely or almost completely in 27 of 34 patients in the thalamotomy group and in 30 of 33 patients in the thalamic-stimulation group. One patient in the thalamic-stimulation group died perioperatively after an intracerebral hemorrhage. With the exception of this incident, thalamic stimulation was associated with significantly fewer adverse effects than thalamotomy. Functional status was reported as improved by 8 patients in the thalamotomy group, as compared with 18 patients in the thalamic-stimulation group (P=0.01)., Conclusions: Thalamic stimulation and thalamotomy are equally effective for the suppression of drug-resistant tremor, but thalamic stimulation has fewer adverse effects and results in a greater improvement in function.