Subthalamotomy in Treatment of Parkinsonian Tremor

Abstract

N THE neurosurgical treatment of parkinsonian tremor, a major question to be ,answered is, where is the optimum site of target for the lesion? The present study is an attempt to evaluate the posterior ventrolateral area of the thalamus, internal capsule, medial region of the globus pallidus and posterior subthalamus. The comparative value of lesions in these structures was determined by (1) noting differences in reduction of tremor associated with insertion of electrodes, and (~) a comparison of the amount of radio-frequency electrical energy (expressed as Boyle-time factor) necessary to obtain over 75 per cent reduction in tremor. The primary objective of this presentation is to demonstrate that lesions in the posterior subthalamus are the most efficient for reducing parkinsonian tremor. Technique Patients. From a group of 150 parkinsonian patients with varying degrees of tremor and rigidity, only those patients having unilateral or bilateral tremor as the major finding were utilized for this study. Tremor was bilateral in the majority of the 58 patients although usually it was more pronounced on one side. The mean age of the patients was 58 and ranged from 41 to 80 years. All patients had been receiving a variety of medications before operation which did not satisfactorily control the tremor. Patients with bilateral tremor were replaced on medication postoperatively. Since these observations were made in patients distributed over the past 7 years, the traditionally desired 5-year detailed follow-up was not possible. The shortest period of follow-up was 4 months (3 patients). Operation. A total of 7~ operations were performed in the 58 patients. Bilateral operations were done in 6 patients and in 1 it was repeated. Repeated unilateral operations were performed in 6 and the rest of the patients had unilateral procedures. Operations were done with patients

Deep brain stimulation in the subthalamic area is more effective than nucleus ventralis intermedius stimulation for bilateral intention tremor

“…Thus, our data corroborate the concept that the subthalamic area is superior to the ventralis intermedius nucleus in suppressing severe 754 intention tremor. This has been proposed almost since ablative procedures in the ventro-lateral thalamus had become an established treatment, and this is supported by the fact that the electrical energy required to excite myelinated fibre tracts is lower than that required for somata [3,5,10,30,46,47,57,58,61,62].…”

“…Efficient suppression of intention tremor may be mediated by different structures contained in the subthalamic area, e.g. the zona incerta known to harbour tremor cells, the fields of Forel H 2 , the prelemniscal radiation, and, possibly, dorsal parts of the subthalamic nucleus [5,10,30,36,38,46,47,57,58,61,62]. Notably, with DBS in the subthalamic area efferents from deep cerebellar nuclei will be modulated along their course through the prerubral field and along the zona incerta [24,44,54].…”

“…These favourable effects have been ascribed to the zona incerta, prelemniscal radiation (RAPRL), fields of Forel, but also the subthalamic nucleus [3,5,10,28,30,33,38,40,46,47,57,58,61,62]. Thus, clearly distinct stereotactic targets located several millimeters apart have been suggested to result in best tremor suppression.…”

The History and Future of Deep Brain Stimulation

“…Although the dorsal STN and the zona incerta had been targeted in the 1960s, 49 this region of the brain had been avoided by most stereotactic surgeons in the 1950s and 1960s due to fear of causing ballism, a well described movement disorder after strokes in this region. However, DeLong et al's 43 experiments led to an understanding of the importance of the STN in the brain circuitry involved in PD and a nonhuman primate model of PD was developed in which to test these ideas, the N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkey.…”

Deep Brain Stimulation for Obesity

“…While the precise mechanism of DBS remains unclear, it is well-established that high-frequency electrical stimulation clinically mimics the effects of neural ablative procedures [19][20]. However, the ability to titrate and/or reverse the effects of DBS make it the preferred method of neuromodulation [21][22][23][24]. Recent clinical trials of DBS in chronic cluster headache, Alzheimer's disease, and depression and obsessive-compulsive disorder have demonstrated the safety and efficacy of targeting the hypothalamus and reward circuitry of the brain with electrical stimulation, and thus provide the basis for a neuromodulatory approach to treatment-refractory obesity [16,[25][26][27].…”