A randomized double-blind crossover trial comparing subthalamic and pallidal deep brain stimulation for dystonia

Abstract

Object The authors' aim was to compare the subthalamic nucleus (STN) with the globus pallidus internus (GPi) as a stimulation target for deep brain stimulation (DBS) for medically refractory dystonia. Methods In a prospective double-blind crossover study, electrodes were bilaterally implanted in the STN and GPi of 12 patients with focal, multifocal, or generalized dystonia. Each patient was randomly selected to undergo initial bilateral stimulation of either the STN or the GPi for 6 months, followed by bilateral stimulation of the other nucleus for another 6 months. Preoperative and postoperative ratings were assessed by using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and video recordings. Quality of life was evaluated by using questionnaires (36-item Short Form Health Survey). Supplemental Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) scores were assessed for patients with focal dystonia (torticollis) by examining the video recordings. Results On average for all patients, DBS improved the BFMDRS movement scores (p < 0.05) and quality of life physical scores (p < 0.01). After stimulation of the STN, the mean 6-month improvement in BFMDRS movement score was 13.8 points; after stimulation of the GPi, this improvement was 9.1 points (p = 0.08). Quality of life did not differ significantly regardless of which nucleus was stimulated. All 12 patients accepted 6 months of stimulation of the STN, but only 7 accepted 6 months of stimulation of the GPi. Among those who rejected stimulation of the GPi, 3 accepted concomitant stimulation of both the STN and GPi for 6 months, resulting in improved quality of life physical and mental scores and BFMDRS movement scores. Among the 4 patients who were rated according to TWSTRS, after 6 months of stimulation of both the STN and GPi, TWSTRS scores improved by 4.7% after stimulation of the GPi and 50.8% after stimulation of the STN (p = 0.08). Conclusions The STN seems to be a well-accepted, safe, and promising stimulation target in the treatment of dystonia, but further studies are necessary before the optimal target can be concluded. Simultaneous stimulation of the STN and GPi should be further investigated. Clinical trial registration no.: KF 01-110/01 (Committees on Biomedical Research Ethics of the Capital Region of Denmark).

Treatment of Dystonia

“…For example, the Vim nucleus of the thalamus has been reported to be effective for patients with dystonic tremor, although in small numbers (~30 cases) [82]. The subthalamic nucleus (STN) has been studied as an alternative target for primary and tardive dystonia [83][84][85][86]. Most of these studies have included small numbers of patients, that is, fewer than 10 patients.…”

“Rescue” of bilateral subthalamic stimulation by bilateral pallidal stimulation: case report

“…A third rationale for adding GPi DBS in our patient was the prominence of dystonia among his symptoms. Clinical observation has suggested that pallidal stimulation may be beneficial for dystonic symptoms, 28 although subthalamic stimulation has recently been shown to also be effective for primary generalized and segmental dystonia. 22,28 Prior reports have studied the possibility of co-targeting STN and GPi in patients with PD.…”

Understanding dystonia: diagnostic issues and how to overcome them

“…Other treatments have been studied for dystonia. Subthalamic nucleus stimulation and simultaneous GPi and subthalamic nucleus stimulation are emerging as promising in the surgical treatment of dystonia 105 . Apparently subthalamic nucleus stimulation does not impair working memory and attention, as has been reported in PD 106 .…”