Treatment of dystonic syndromes by chronic electrical stimulation of the internal globus pallidus.

AIM: Dystonia is a medically intractable condition causing twisting or myoclonic movements and abnormal postures. There is an important heterogeneity among etiologies of dystonia. The electrical stimulation of the globus pallidus has been used successfully in primary generalized dystonia. The aim of this study was to examine the long-term efficacy and safety of deep brain stimulation (DBS) in the treatment of primary and secondary generalized dystonia in children and adults. METHODS: Fifty-three patients were included. Electrodes were bilaterally implanted under stereotactic guidance and connected to neurostimulators, subcutaneously inserted. Efficacy was evaluated by comparing scores on the clinical and functional Burke-Marsden-Fahn dystonia rating scales (BMFDRS) before and after implantation. Patients were divided into 3 groups: group 1 comprised 15 patients with DYT1 dystonia; group 2, 17 patients with dystonia of unknown etiology and group 3, 21 patients with secondary dystonia. The mean follow-up was 26.6+/-12.3 months for primary dystonia and 23.1+/-11.8 for secondary dystonia. RESULTS: After 1 year, the improvement of the clinical score is 71% in group 1, 74% in group 2 and 31% in group 3. The functional score was improved by 63% in group 1, 49% in group 2 and 7% in group 3. We did not find any significant difference between children and adults. In secondary dystonia, efficacy of the stimulation is more limited. The efficacy of the stimulation improved with time for the 3 groups. COMCLUSION: Electrical stimulation of the internal globus pallidus proved to be an effective treatment for generalized dystonia and should be considered as first-line therapy.

Magnetic resonance imaging stereotactic target localization for deep brain stimulation in dystonic children.

OBJECT: The actual distortion present in a given series of magnetic resonance (MR) images is difficult to establish. The purpose of this study was to validate an MR imaging-based methodology for stereotactic targeting of the internal globus pallidus during electrode implantation in children in whom general anesthesia had been induced. METHODS: Twelve children (mean follow up 1 year) suffering from generalized dystonia were treated with deep brain stimulation by using a head frame and MR imaging. To analyze the influence of distortions at every step of the procedure, the geometrical characteristics of the frame were first controlled using the localizer as a phantom. Then pre- and postoperative coordinates of fixed anatomical landmarks and electrode positions, both determined with the head frame in place, were statistically compared. No significant difference was observed between theoretical and measured dimensions of the localizer (Student's t-test, ¿t¿ > 2.2 for 12 patients) in the x, y, and z directions. No significant differences were observed (Wilcoxon paired-sample test) between the following: 1) pre- and postoperative coordinates of the anterior commissure (AC) (deltax = 0.3+/-0.29 mm and deltay = 0.34+/-0.32 mm) and posterior commissure (PC) (deltax = 0.15+/-0.18 mm and deltay = 0.34+/-0.25 mm); 2) pre- and postoperative AC-PC distance (deltaL = 0.33+/-0.22 mm); and 3) preoperative target and final electrode position coordinates (deltax = 0.24+/-0.22 mm; deltay = 0.19+/-0.16 mm). CONCLUSIONS: In the authors' center, MR imaging distortions did not induce detectable errors during stereotactic surgery in dystonic children. Target localization and electrode implantation could be achieved using MR imaging alone after induction of general anesthesia. The remarkable postoperative improvement in these patients confirmed the accuracy of the procedure (Burke-Marsden-Fahn Dystonia Rating Scale score delta = -83.8%).

Treatment of DYT1-generalised dystonia by stimulation of the internal globus pallidus.

In seven selected patients with dystonia musculorum deformans-1 generalised dystonia (DYT1), continuous bilateral stimulation of the globus pallidus internus was associated with substantial improvement of dystonia and functional disability.

[Treatment of early-onset generalized dystonia by chronic bilateral stimulation of the internal globus pallidus. Apropos of a case]. / Traitement de la dystonie généralisée à début précoce par stimulation chronique bilatérale des globus pallidus internes. A propos d'un cas.

Dystonia musculorum deformans is an inherited severe disease, with a wide clinical polymorphism. The most severe clinical forms with early onset carry a high risk of life-threatening complications. In the absence of any efficient medical treatment, bilateral pallidotomy has previously been reported to be of value in the management of this disease. We report the first clinical case of a severe early-onset generalized dystonia dramatically improved by a bilateral stimulation of the internal globus pallidus. In November 1996, we proposed this neurosurgical procedure for a 8-year-old girl, who had suffered since the age of 3 from severe generalized dystonia, and who progressively became totally dependent and bedridden. She had been under sedation and permanent controlled respiratory assistance for the last two months. The etiology of the disease remained unknown (the DYT1 mutation was absent). Under general anesthesia, we bilaterally implanted a four-contacts electrode in the internal globus pallidus, using the Leksell's stereotactic frame and a 1.5 tesla MRI control. A dramatic improvement was noted 6 weeks later and led us to connect the two electrodes to neurostimulators inserted under the abdominal skin.