Early Globus Pallidus Internus Stimulation in Pediatric Patients With Generalized Primary Dystonia: Long-Term Efficacy and Safety

Abstract

Primary generalized dystonia presents mainly at a young age and commonly is severely disabling. The authors report the long-term follow-up (mean, 73 months; range, 50-101 months) of 5 pediatric patients (mean age at surgery 13 years; range, 8-16 years) undergoing globus pallidus internus deep brain stimulation. Mean improvement in the Burke-Fahn-Marsden movement score was 67.4% (range, 47.0%-87.5%), 75.4% (range, 61.5%-91.7%), and 83.5% (range, 72.0%-93.3%) at 3 months, 12 months, and long-term follow-up (>36 months), respectively. Hardware problems (electrode dislocation/breakage of extension cable, and imminent perforation of extension cable) were observed in 2 patients (operative revision without sequelae). Except for mild dysarthria in 2 patients, no other therapy-related morbidity was observed. The authors found globus pallidus internus stimulation to offer a very effective and safe therapy in pediatric patients with primary dystonia. Early neurosurgical intervention seems to be crucial to prevent irreversible impairment of motor function.

Interventional MRI–guided deep brain stimulation in pediatric dystonia: first experience with the ClearPoint system

“…1,4,6,8,16,18 All of these studies used frame-based stereotaxy with targeting performed on MR images acquired prior to surgery and computationally registered to the frame axes. Improvements in the BFMDRS movement score from baseline to 12 months postimplantation ranged from 62% to 85%, except for one outlier study reporting substantially less benefit.…”

“…1,4,6,8,18,21 Clinical outcome is critically dependent on exact lead placement in the posterior (motor) area of the internal pallidum, 26,28 but surgical methods to achieve excellent lead placement have not been standardized. In adults, the traditional method for DBS lead implantation involves physiological localization while patients are awake.…”

Tolerance of early pallidal stimulation in pediatric generalized dystonia

“…The therapeutic benefit of pallidal DBS has been widely established in the dystonic syndrome irrespective of primary, 1,[5][6][7]10,12,14,16,19,20,22,29 secondary, or heredodegenerative dystonia. 15,39,41 Some studies found the DYT1 mutation to be a prognostic factor of a successful outcome of pallidal DBS, [3][4][5]13,37,42 while others did not.…”

“…The clinical results of pallidal DBS in pediatric patients (≤ 10 years of age) who underwent pallidal DBS are summarized in Table 1. As in adult cases, marked improvements of over 80% in dystonic symptoms, according to the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) for movement, were documented in some early pediatric cases; 1,5,16,29,33 on the other hand, there also exist improvements below 30% on the BFMDRS, 26,32,46 suggesting that a careful evaluation is necessary before attempting surgical intervention in the brain of a patient who is too young. 26 To date, there have been few reports of dystonia recurrence, which may reflect a possible bias that poor outcomes were not published.…”

“…However, there is little evidence to prove that surgery performed at an earlier age results in a better outcome in primary generalized dystonia. 6 Although an early neurosurgical intervention is recommended to prevent irreversible impairment of motor function 29 or secondary spinal deformities 6,12 in dystonic children, the long-term data on early pallidal DBS in pediatric cases are limited, especially in the population aged 15 years or younger. In this paper, we report on 2 pediatric cases treated with early pallidal DBS in which initial clinical benefits were lost over time.…”